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Viologens are organic compounds with the formula (CHNR). In some viologens, the pyridyl groups are further modified.
Viologens are called so, because these compounds produce violet color on reduction [violet + Latin gen, generator of].
The viologen paraquat (R = methyl), is a widely used herbicide. As early as in the 1930s, paraquat was being used as an oxidation-reduction indicator, because it becomes violet on reduction.
Other viologens have been commercialized because they can change color reversibly many times through reduction and oxidation. The name viologen alludes to violet, one color it can exhibit, and the radical cation (CHNR) is colored intensely blue. | 1 | Solid-state chemistry |
Bengt Aurivillius is a member of the Aurivillius family, his father was the entomologist Christopher Aurivillius. His wife was crystallographer Karin Aurivillius. | 1 | Solid-state chemistry |
Douglas A. Keszler is a distinguished professor in the Department of Chemistry at Oregon State University, adjunct professor in the Physics Department at OSU and adjunct professor in the Department of Chemistry at University of Oregon. He is also the director of the Center for Sustainable Materials Chemistry, and a member of the Oregon Nanoscience and Microtechnologies Institute (ONAMI) leadership team. | 1 | Solid-state chemistry |
The PTC rubber can be rolled into thin sheets and laminated with copper. The copper is in turn connected to a voltage to provide the electrical field inside the material necessary to trigger the tunneling effect. The sheets can be formed into any shape and size.
PTC rubber sheets can be used as thin flexible PTC heaters. These heaters will provide high power when they are cold and rapidly heat up themselves to a constant temperature and remain there virtually unaffected by changes in the ambient conditions. They can be powered with any voltage between 5 and 230 V, AC or DC.
The PTC rubber material is a self-regulating heater. It produces the same amount of heat in each point of the heater as is conducted and radiated away from the heater to the object it is attached to, and its surroundings. It is in constant thermal equilibrium with the environment, point by point. A measure of the power produced by the heater is actually a measurement of the heat transfer between the heater and the object. Hence, it can be used as a heat transfer sensor. | 1 | Solid-state chemistry |
In 1976, Hazen joined the Carnegie Institutions Geophysical Laboratory as a research associate. After a brief stint measuring optical properties of lunar minerals with Peter Bell and David Mao, he started to do X-ray crystallography with Larry Finger. He later recalled, "It was a match made in mineralogical heaven: Larry loved to write code, build machines, and analyze data; I loved to mount crystals, run the diffractometers, and write papers." They collaborated for two decades and determined about a thousand crystal structures at variable pressures and temperatures, work summarized in their 1982 book Comparative Crystal Chemistry'.
Much of the work that Hazen was doing could be classified as mineral physics, a cross between geophysics and mineralogy. Although the field had pioneering contributions from the Nobel Prize winner Percy Bridgman and a student of his, Francis Birch, in the early- to mid-20th century, it did not have a name until the 1960s, and in the 1970s some scientists were concerned that a more interdisciplinary approach was needed to understand the relationship between interatomic forces and mineral properties. Hazen and Prewitt co-convened the first mineral physics conference; it was held on October 17–19, 1977 at the Airlie House in Warrenton, Virginia. | 1 | Solid-state chemistry |
; 60-series:
* 2NOR60, 2.NOR60 - Twin NOR (black)
* 4NOR60, 4.NOR60 - Quadruple NOR (black)
* 2.IA60, 2IA60 - Twin inverter amplifier for low power output (blue)
* LPA60 - Twin low power output
* 2.LPA60, 2LPA60 - Twin low power output (blue)
* PA60 - Medium power output (blue)
* HPA60 - High power output (black)
* 2.SF60, 2SF60 - Twin input switch filter (green)
* TU60 - Timer (red)
* FF60 - Flip-flop
* GLD60 - Grounded load driver (black)
; 61-series:
* TT61 - Trigger transformer
* UPA61 - Universal power amplifier
* RSA61 - Rectifier and synchroniser
* DOA61 - Differential operational amplifier
* 2NOR61, 2.NOR61 - Twin NOR
; 90-series:
* PS90 - Pulse shaper (green)
* FF90 - Flip-flop (red)
* 2TG90, 2.TG90 - Twin trigger gate (red)
; Accessories:
* PSU61 - Power supply
* PCB60 - Printed wiring board
* MC60 - Mounting chassis
* UMC60 - Universal mounting chassis
* MB60 - Mounting bar | 1 | Solid-state chemistry |
Rustum Roy (July 3, 1924 – August 26, 2010) was a physicist, born in India, who became a professor at Pennsylvania State University and was a leader in materials research. As an advocate for interdisciplinarity, he initiated a movement of materials research societies and, outside of his multiple areas of scientific and engineering expertise, wrote impassioned pleas about the need for a fusion of religion and science and humanistic causes.
Later in life he held visiting professorships in materials science at Arizona State University, and in medicine at the University of Arizona. | 1 | Solid-state chemistry |
*: Great Cross of the National Order of Scientific Merit (2002)
*: Chevalier de la Légion d'honneur (2005)
*: Gold and Silver Star of the Order of the Rising Sun (2015)
*: Order of Friendship (2009) | 1 | Solid-state chemistry |
The term solid-state became popular at the beginning of the semiconductor era in the 1960s to distinguish this new technology. A semiconductor device works by controlling an electric current consisting of electrons or holes moving within a solid crystalline piece of semiconducting material such as silicon, while the thermionic vacuum tubes it replaced worked by controlling a current of electrons or ions in a vacuum within a sealed tube.
Although the first solid-state electronic device was the cats whisker detector, a crude semiconductor diode invented around 1904, solid-state electronics started with the invention of the transistor in 1947. Before that, all electronic equipment used vacuum tubes, because vacuum tubes were the only electronic components that could amplify'—an essential capability in all electronics. The transistor, which was invented by John Bardeen and Walter Houser Brattain while working under William Shockley at Bell Laboratories in 1947, could also amplify, and replaced vacuum tubes. The first transistor hi-fi system was developed by engineers at GE and demonstrated at the University of Philadelphia in 1955. In terms of commercial production, The Fisher TR-1 was the first "all transistor" preamplifier, which became available mid-1956. In 1961, a company named Transis-tronics released a solid-state amplifier, the TEC S-15.
The replacement of bulky, fragile, energy-hungry vacuum tubes by transistors in the 1960s and 1970s created a revolution not just in technology but in people's habits, making possible the first truly portable consumer electronics such as the transistor radio, cassette tape player, walkie-talkie and quartz watch, as well as the first practical computers and mobile phones. Other examples of solid state electronic devices are the microprocessor chip, LED lamp, solar cell, charge coupled device (CCD) image sensor used in cameras, and semiconductor laser.
Also during the 1960s and 1970s, television set manufacturers switched from vacuum tubes to semiconductors, and advertised sets as "100% solid state" even though the cathode-ray tube (CRT) was still a vacuum tube. It meant only the chassis was 100% solid-state, not including the CRT. Early advertisements spelled out this distinction, but later advertisements assumed the audience had already been educated about it and shortened it to just "100% solid state". LED displays can be said to be truly 100% solid-state. | 1 | Solid-state chemistry |
In 1957, Davies suggested a method based on calculating a value based on the chemical groups of the molecule. The advantage of this method is that it takes into account the effect of stronger and weaker hydrophilic groups. The method works as follows:
where:
- Number of hydrophilic groups in the molecule
- Value of the hydrophilic groups (see tables)
- Number of lipophilic groups in the molecule | 0 | Colloidal Chemistry |
Nanoclusters potentially have many areas of application as they have unique optical, electrical, magnetic and reactivity properties. Nanoclusters are biocompatible, ultrasmall, and exhibit bright emission, hence promising candidates for fluorescence bio imaging or cellular labeling. Nanoclusters along with fluorophores are widely used for staining cells for study both in vitro and in vivo. Furthermore, nanoclusters can be used for sensing and detection applications. They are able to detect copper and mercury ions in an aqueous solution based on fluorescence quenching. Also many small molecules, biological entities such as biomolecules, proteins, DNA, and RNA can be detected using nanoclusters. The unique reactivity properties and the ability to control the size and number of atoms in nanoclusters have proven to be a valuable method for increasing activity and tuning the selectivity in a catalytic process. Also since nanoparticles are magnetic materials and can be embedded in glass these nanoclusters can be used in optical data storage that can be used for many years without any loss of data. | 0 | Colloidal Chemistry |
The surface tension at the border between the fluid lining and the inhaled gas (gas/fluid interface) in alveoli determines the motion of the alveoli as a whole. According to Lapace's Law, high surface tension in the gas/fluid interface of alveoli prevents the alveoli from inflating, which causes lung collapse. lipid arrangement in the fluid lining of alveoli is the primary determining factor of this surface tension since the lipids form a thin film (monolayer) on the surface of the fluid lining at the gas/fluid interface. Different lipids allow for different ranges of motion and can be compacted different.
SP-B plays a role in this by selected certain lipids and inserting them into the gas/fluid interface. The lipid shown to be most needed on this surface (Dipalmitoylphosphatidylcholine) does not easily move to the gas/fluid interface, but SP-B helps ease and speed up this process.
SP-B also indirectly reduces surface tension by organizing the lipids underneath the surface of the gas/fluid interface in structures called tubular myelin. Effectively, SP-B cuts and pastes pieces of the lipid bilayers to form the three dimensional structure of the tubular myelin. This structure is the support and lipid source for the gas/fluid interface, where surface tension is a critical factor in lung function. | 0 | Colloidal Chemistry |
As the nanotechnology industry has grown, nanoparticles have brought UFPs more public and regulatory attention. UFP risk assessment research is still in the very early stages. There are continuing debates about whether to regulate UFPs and how to research and manage the health risks they may pose. As of March 19, 2008, the EPA does not yet regulate or research ultrafine particles, but has drafted a Nanomaterial Research Strategy, open for independent, external peer review beginning February 7, 2008 (Panel review on April 11, 2008). There is also debate about how the European Union (EU) should regulate UFPs. | 0 | Colloidal Chemistry |
Dating back to the nineteenth century there are reports of these particles by authors such as Jacques-Louis Bournon in 1813 for marcasite, and Gustav Rose in 1831 for gold. In mineralogy and the crystal twinning literature they are referred to as a type of cyclic twins where a number of identical single crystal units are arranged in a ring-like pattern where they all join at a common point or line. The name comes from them having five members (single crystals). The older literature was mainly observational, with information on many materials documented by Victor Mordechai Goldschmidt in his Atlas der Kristallformen. Drawings are available showing their presence in marcasite, gold, silver, copper and diamond. New mineral forms with a fiveling structure continue to be found, for instance pentagonite, whose structure was first decoded in 1973, is named because it is often found with the five-fold twinning.
Most modern analysis started with the observation of these particles by Shozo Ino and Shiro Ogawa in 1966-67, and independently but slightly later (which they acknowledged) work by John Allpress and John Veysey Sanders. In both cases these were for vacuum deposition of metal onto substrates in very clean (ultra-high vacuum) conditions, where nanoparticle islands of size 10-50 nm were formed during thin film growth. Using transmission electron microscopy and diffraction these authors demonstrated the presence of the five single crystal units in the particles, and also the twin relationships. They also observed single crystals and a related type of icosahedral nanoparticle. They called the five-fold and icosahedral crystals multiply twinned particles (MTPs). In the early work near perfect decahedron (pentagonal bipyramid) and icosahedron shapes were formed, so they were called decahedral MTPs or icosahedral MTPs, the names connecting to the decahedral () and icosahedral () point group symmetries. Parallel, and apparently independent there was work on larger metal whiskers (nanowires) which sometimes showed a very similar five-fold structure, an occurrence reported in 1877 by Gerhard vom Rath. There was fairly extensive analysis following this, particularly for the nanoparticles, both of their internal structure by some of the first electron microscopes that could image at the atomic scale, and by various continuum or atomic models as cited later.
Following this early work there was a large effort, mainly in Japan, to understand what were then called "fine particles", but would now be called nanoparticles. By heating up different elements so atoms evaporated and were then condensed in an inert argon atmosphere, fine particles of almost all the elemental solids were made and then analyzed using electron microscopes. The decahedral particles were found for all face centered cubic materials and a few others, often together with other shapes.While there was some continuing work over the following decades, it was with the National Nanotechnology Initiative that substantial interest was reignited. At the same time terms such as pentagonal nanoparticle, pentatwin, or five-fold twin became common in the literature, together with the earlier names. A large number of different methods have now been published for fabricating fivelings, sometimes with a high yield but often as part of a larger population of different shapes. These range from colloidal solution methods to different deposition approaches. It is documented that fivelings occur frequently for diamond, gold and silver, sometimes for copper or palladium and less often for some of the other fcc metals such as nickel. There are also cases such as pentagonite where the crystal structure allows for five-fold twinning with minimal to no elastic strain (see later). There is work where they have been observed in colloidal crystals consisting of ordered arrays of nanoparticles, and single crystals composed on individual decahedral nanoparticles. There has been extensive modeling by many different approaches such as embedded atom, many body, molecular dynamics, tight binding approaches, and density functional theory methods as recently discussed by Francseca Baletto and Riccardo Ferrando and also discussed for energy landscapes later. | 1 | Solid-state chemistry |
This oxide of tin has been utilized as a mordant in the dyeing process since ancient Egypt. A German by the name of Kuster first introduced its use to London in 1533 and by means of it alone, the color scarlet was produced there. | 1 | Solid-state chemistry |
Carbon nanofoam is an allotrope of carbon discovered in 1997 by Andrei V. Rode and co-workers at the Australian National University in Canberra. It consists of a cluster-assembly of carbon atoms strung together in a loose three-dimensional web. The fractal-like bond structure consists of sp graphite-like clusters connected by sp bonds. The sp bonds are located mostly on the surface of the structure and make up 15% to 45% of the material, making its framework similar to diamond-like carbon films. The material is remarkably light, with a density of 2-10 x 10 g/cm (0.0012 lb/ft) and is similar to an aerogel. Other remarkable physical properties include the large surface area of 300–400 m/g (similar to zeolites). of nanofoam weighs about .
Each cluster is about 6 nanometers wide and consists of about 4000 carbon atoms linked in graphite-like sheets that are given negative curvature by the inclusion of heptagons among the regular hexagonal pattern. This is the opposite of what happens in the case of buckminsterfullerenes in which carbon sheets are given positive curvature by the inclusion of pentagons.
The large-scale structure of carbon nanofoam is similar to that of an aerogel, but with 1% of the density of previously produced carbon aerogels—or only a few times the density of air at sea level. Unlike carbon aerogels, carbon nanofoam is a poor electrical conductor. The nanofoam contains numerous unpaired electrons, which Rode and colleagues propose is due to carbon atoms with only three bonds that are found at topological and bonding defects. This gives rise to what is perhaps carbon nanofoam's most unusual feature: it is attracted to magnets, and below −183 °C can itself be made magnetic.
Carbon nanofoam is the only form of pure carbon known to be ferromagnetic which is unusual for a carbon allotrope. Ferromagnetism is an intrinsic property observed in the carbon nanofoam and may be accounted for by its complex structure. Impurities in the material are excluded as the source of magnetism as they are not sufficient for the strong magnetization observed. Researchers postulate that embedded carbon atoms with unpaired electrons carry enough of a magnetic moment to lead to strong magnetization. The sheet curvature localizes unpaired electrons by breaking up the π-electron clouds and sterically protects the electrons which normally would be too reactive to persist. The ferromagnetism of the carbon nanofoam is sensitive to time and temperature. Some magnetism is lost within the first few hours of synthesis, however most of it is persistent. Carbon nanofoam may have some application in spintronic devices which exploits electron spin as a further degree of freedom.
Carbon nanofoam may be suitable for hydrogen storage due to its low density and high surface area. Preliminary experimentation has shown that hydrogen can be stored in the nanofoam at room temperature in a reversible process.
Synthesis
Carbon nanofoam clusters can be synthesized through high-repetition-rate laser ablation in inert gases such as argon. Short (fs), low-energy (µJ) pulses delivered at high rates of repetition (10 kHz – 100 MHz) generate carbon vapors for deposition. Ambient gas is heated from room temperature with the atomized carbon which leads to an increase in the partial density of the carbon in the chamber. In optimal conditions, the inert gas does not cool down but maintains its high temperature between cycles of formation. Subsequent cycles in the chamber are carried out at temperatures above the formation threshold temperature initiating sp bonding. The increase in density and temperature promotes favorable conditions for the formation of carbonaceous clusters. The rate of consumption exceeds the rate of evaporation by laser ablation and thus the formation is in a non-equilibrium state. | 0 | Colloidal Chemistry |
The third case described by Asakura and Oosawa is two plates in a solution of polymers. Due to the size of the polymers, the concentration of polymers in the neighborhood of the plates is reduced, which result the conformational entropy of the polymers being decreased. The case can be approximated by modeling it as diffusion in a vessel with walls which absorb diffusing particles. The force, , can then be calculated according to:
In this equation is the attraction from the osmotic effect. is the repulsion due to chain molecules confined between plates. is on order of , the mean end-to-end distance of chain molecules in free space. | 0 | Colloidal Chemistry |
One of the challenges in generating in vivo like cultures or tissue in vitro is the difficulty in co-culturing different cell types. Because of the ability of 3D cell culturing by magnetic levitation to bring cells together, co-culturing different cell types is possible. Co-culturing of different cell types can be achieved at the onset of levitation, by mixing different cell types in before levitation or by magnetically guiding 3D cultures in an invasion assay format.
The unique ability to manipulate cells and shape tissue magnetically offers new possibilities for controlled co-culturing and invasion assays. Co-culturing in a realistic tissue architecture is critical for accurately modeling in vivo conditions, such as for increasing the accuracy of cellular assays as shown in the figure below.
Shown in the picture above is an invasion assay of magnetically levitated multicellular spheroids; fluorescence images of human glioblastoma (GBM) cells (green; GFP-expressing cells) and normal human astrocytes (NHA) (red; mCherry-labelled) cultured separately and then magnetically guided together (left, time 0). Invasion of GBM into NHA in 3D culture provides a powerful new assay for basic cancer biology and drug screening (right, 12h to 252h). | 0 | Colloidal Chemistry |
The characteristic shape of the JT-split APES has specific consequences for the nuclear dynamics, here considered in the fully quantum sense. For sufficiently strong JT coupling, the minimum points are sufficiently far (at least by a few vibrational energy quanta) below the JT intersection. Two different energy regimes are then to be distinguished, those of low and high energy.
* In the low-energy regime the nuclear motion is confined to regions near the "minimum energy points". The distorted configurations sampled impart their geometrical parameters on, for example, the rotational fine structure in a spectrum. Due to the existence of barriers between the various minima in the APES, like those appearing due to the warping of the , motion on the low-energy regime is usually classified as either a static JTE, dynamic JTE or incoherent hopping. Each regime shows particular fingerprints on experimental measurements.
:* Static JTE: In this case, the system is trapped in one of the lowest-energy minima of the APES (usually determined by small perturbations created by the environment of the JT system) and does not have enough energy to cross the barrier towards another minimum during the typical time associated to the measurement. Quantum dynamical effects like tunnelling are negligible, and effectively the molecule or solid displays the low symmetry associated with a single minimum.
:* Dynamic JTE: In this case, the barriers are sufficiently small compared to, for example, the zero-point energy associated to the minima, so that vibronic wavefunctions (and all observables) display the symmetry of the reference (undistorted) system. In the linear E ⊗ e problem, the motion associated to this regime would be around the circular path in the figure. When the barrier is sufficiently small, this is called (free) pseudorotation (not to be confused with the rotation of a rigid body in space, see difference between real and pseudo rotations illustrated [http://www.nottingham.ac.uk/~ppzjld/pseudorotate.htm here] for the fullerene molecule C). When the barrier between the minima and the saddle points on the warped path exceeds a vibrational quantum, pseudorotational motion is slowed down and occurs through tunnelling. This is called hindered pseudorotation. In both free and hindered pseudorotation, the important phenomenon of the geometric (Berry) phase alters the ordering of the levels.
:* Incoherent hopping: Another way in which the system can overcome the barrier is through thermal energy. In this case, while the system moves throughout the minima of the system, the state is not a quantum coherent one but a statistical mixture. This difference can be observed experimentally.
* The dynamics is quite different for high energies, such as occur from an optical transition from a non-degenerate initial state with a high-symmetry (JT undistorted) equilibrium geometry into a JT distorted state. This leads the system to the region near the conical intersection of the JT-split APES in the centre of the figure. Here the nonadiabatic couplings become very large and the behaviour of the system cannot be described within the familiar Born–Oppenheimer (BO) separation between the electronic and nuclear motions. The nuclear motion ceases to be confined to a single, well-defined APES and the transitions between the adiabatic surfaces occur yielding effects like Slonzcewsky resonances. In molecules this is usually a femtosecond timescale, which amounts to ultrafast (femtosecond) internal conversion processes, accompanied by broad spectral bands also under isolated-molecule conditions and highly complex spectral features. Examples for these phenomena will be covered in section .
As already stated above, the distinction of low and high energy regimes is valid only for sufficiently strong JT couplings, that is, when several or many vibrational energy quanta fit into the energy window between the conical intersection and the minimum of the lower JT-split APES. For the many cases of small to intermediate JT couplings this energy window and the corresponding adiabatic low-energy regime does not exist. Rather, the levels on both JT-split APES are intricately mixed for all energies and the nuclear motion always proceeds on both JT split APES simultaneously. | 1 | Solid-state chemistry |
Iron phosphide is a chemical compound of iron and phosphorus, with a formula of FeP. Its physical appearance is grey, hexagonal needles.
Manufacturing of iron phosphide takes place at elevated temperatures, where the elements combine directly. Iron phosphide reacts with moisture and acids producing phosphine (PH), a toxic and pyrophoric gas.
Iron phosphide can be used as a semiconductor. It has use in high power, high frequency applications, such as laser diodes.
Below a Néel temperature of about 119 K, FeP takes on an helimagnetic structure. | 1 | Solid-state chemistry |
Nuclear magnetic resonance crystallography (NMR crystallography) is a method which utilizes primarily NMR spectroscopy to determine the structure of solid materials on the atomic scale. Thus, solid-state NMR spectroscopy would be used primarily, possibly supplemented by quantum chemistry calculations (e.g. density functional theory), powder diffraction etc. If suitable crystals can be grown, any crystallographic method would generally be preferred to determine the crystal structure comprising in case of organic compounds the molecular structures and molecular packing. The main interest in NMR crystallography is in microcrystalline materials which are amenable to this method but not to X-ray, neutron and electron diffraction. This is largely because interactions of comparably short range are measured in NMR crystallography. | 1 | Solid-state chemistry |
Clay nanoparticles, when incorporated into polymer matrices, increase reinforcement, leading to stronger plastics, verifiable by a higher glass transition temperature and other mechanical property tests. These nanoparticles are hard, and impart their properties to the polymer (plastic). Nanoparticles have also been attached to textile fibers in order to create smart and functional clothing. | 0 | Colloidal Chemistry |
The electrical and thermal conductivity and magnetic property of metals enhance the electrical conductivity and antibacterial property of nanocomposite hydrogels when incorporated. The electrical conducting property is necessary for the hydrogels to start forming functional tissues and be used as imaging agents, drug delivery systems, conductive scaffolds, switchable electronics, actuators, and sensors. | 0 | Colloidal Chemistry |
After working as a lecturer at Madurai Kamaraj University for four years, he joined John B. Goodenough's lab as a Research Associate, first at Oxford University and then at the University of Texas at Austin. Manthiram joined the faculty of the University of Texas at Austin in 1991. | 1 | Solid-state chemistry |
The gold number is the minimum weight (in milligrams) of a protective colloid required to prevent the coagulation of 10 ml of a standard hydro gold sol when 1 ml of a 10% sodium chloride solution is added to it. It was first used by Richard Adolf Zsigmondy in 1901.
An electrical double layer is normally present on the gold sol particles, resulting in electrostatic repulsion between the particles. The sodium chloride ions disrupt this electrical double layer, causing coagulation to occur.
The coagulation of gold sol results in an increase in particle size, indicated by a colour change from red to blue or purple. The higher the gold number, the lower the protective power of the colloid, because a greater amount of colloid is required to prevent coagulation.
The gold number of some colloids are given below. | 0 | Colloidal Chemistry |
In chemistry, a suspension is a heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation. The particles may be visible to the naked eye, usually must be larger than one micrometer, and will eventually settle, although the mixture is only classified as a suspension when and while the particles have not settled out. | 0 | Colloidal Chemistry |
Commercial lecithin, as used by food manufacturers, is a mixture of phospholipids in oil. The lecithin can be obtained by water degumming the extracted oil of seeds. It is a mixture of various phospholipids, and the composition depends on the origin of the lecithin. A major source of lecithin is soybean oil. Because of the EU requirement to declare additions of allergens in foods, in addition to regulations regarding genetically modified crops, a gradual shift to other sources of lecithin (such as sunflower lecithin) is taking place. The main phospholipids in lecithin from soy and sunflower are phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylserine, and phosphatidic acid. They are often abbreviated to PC, PI, PE, PS and PA, respectively. Purified phospholipids are produced by companies commercially. | 0 | Colloidal Chemistry |
Although the nearly free electron approximation is able to describe many properties of electron band structures, one consequence of this theory is that it predicts the same number of electrons in each unit cell. If the number of electrons is odd, we would then expect that there is an unpaired electron in each unit cell, and thus that the valence band is not fully occupied, making the material a conductor. However, materials such as CoO that have an odd number of electrons per unit cell are insulators, in direct conflict with this result. This kind of material is known as a Mott insulator, and requires inclusion of detailed electron-electron interactions (treated only as an averaged effect on the crystal potential in band theory) to explain the discrepancy. The Hubbard model is an approximate theory that can include these interactions. It can be treated non-perturbatively within the so-called dynamical mean-field theory, which attempts to bridge the gap between the nearly free electron approximation and the atomic limit. Formally, however, the states are not non-interacting in this case and the concept of a band structure is not adequate to describe these cases. | 1 | Solid-state chemistry |
The underlying cause of the Jahn–Teller effect is the presence of molecular orbitals that are both degenerate and open shell (i.e., incompletely occupied). This situation is not unique to coordination complexes and can be encountered in other areas of chemistry. In organic chemistry the phenomenon of antiaromaticity has the same cause and also often sees molecules distorting; as in the case of cyclobutadiene and cyclooctatetraene (COT). | 1 | Solid-state chemistry |
Most surfactants are organic compounds with hydrophilic "heads" and hydrophobic "tails." The "heads" of surfactants are polar and may or may not carry an electrical charge. The "tails" of most surfactants are fairly similar, consisting of a hydrocarbon chain, which can be branched, linear, or aromatic. Fluorosurfactants have fluorocarbon chains. Siloxane surfactants have siloxane chains.
Many important surfactants include a polyether chain terminating in a highly polar anionic group. The polyether groups often comprise ethoxylated (polyethylene oxide-like) sequences inserted to increase the hydrophilic character of a surfactant. Polypropylene oxides conversely, may be inserted to increase the lipophilic character of a surfactant.
Surfactant molecules have either one tail or two; those with two tails are said to be double-chained.
Most commonly, surfactants are classified according to polar head group. A non-ionic surfactant has no charged groups in its head. The head of an ionic surfactant carries a net positive, or negative, charge. If the charge is negative, the surfactant is more specifically called anionic; if the charge is positive, it is called cationic. If a surfactant contains a head with two oppositely charged groups, it is termed zwitterionic, or amphoteric. Commonly encountered surfactants of each type include: | 0 | Colloidal Chemistry |
Nanogeoscience deals with structures, properties and behaviors of nanoparticles in soils, aquatic systems and atmospheres. One of the key features of nanoparticles is the size-dependence of the nanoparticle stability and reactivity. This arises from the large specific surface area and differences in surface atomic structure of nanoparticles at small particle sizes. In general, the free energy of nanoparticles is inversely proportional to their particle size. For materials that can adopt two or more structures, size-dependent free energy may result in phase stability crossover at certain sizes. Free energy reduction drives crystal growth (atom-by-atom or by oriented attachment ), which may again drive the phase transformation due to the change of the relative phase stability at increasing sizes. These processes impact the surface reactivity and mobility of nanoparticles in natural systems.
Well-identified size-dependent phenomena of nanoparticles include:
* Phase stability reversal of bulk (macroscopic) particles at small sizes. Usually, a less stable bulk-phase at low temperature (and/or low pressure) becomes more stable than the bulk-stable phase as the particle size decreases below a certain critical size. For instance, bulk anatase (TiO) is metastable with respect to bulk rutile (TiO). However, in air, anatase becomes more stable than rutile at particle sizes below 14 nm. Similarly, below 1293 K, wurtzite (ZnS) is less stable than sphalerite (ZnS). In vacuum, wurtzite becomes more stable than sphalerite when the particle size is less than 7 nm at 300 K. At very small particle sizes, the addition of water to the surface of ZnS nanoparticles can induce a change in nanoparticle structure and surface-surface interactions can drive a reversible structural transformation upon aggregation/disaggregation. Other examples of size-dependent phase stability include systems of AlO, ZrO, C, CdS, BaTiO, FeO, CrO, MnO, NbO, YO, and Au-Sb.
* Phase transformation kinetics is size-dependent and transformations usually occur at low temperatures (less than several hundred degrees). Under such conditions, rates of surface nucleation and bulk nucleation are low due to their high activation energies. Thus, phase transformation occurs predominantly via interface nucleation that depends on contact between nanoparticles. As a consequence, the transformation rate is particle number (size)-dependent and it proceeds faster in densely packed (or highly aggregated) than in loosely packed nanoparticles. Complex concurrent phase transformation and particle coarsening often occur in nanoparticles.
* Size-dependent adsorption on nanoparticles and oxidation of nanominerals.
These size-dependent properties highlight the importance of the particle size in nanoparticle stability and reactivity. | 0 | Colloidal Chemistry |
Bismuth telluride is a well-studied topological insulator. Its physical properties have been shown to change at highly reduced thicknesses, when its conducting surface states are exposed and isolated. These thin samples are obtained through either epitaxy or mechanical exfoliation.
Epitaxial growth methods such as molecular beam epitaxy and metal organic chemical vapor deposition are common methods of obtaining thin samples. The stoichiometry of samples obtained through such techniques can vary greatly between experiments, so Raman spectroscopy is often used to determine relative purity. However, thin samples are resistant to Raman spectroscopy due to their low melting point and poor heat dispersion.
The crystalline structure of allows for mechanical exfoliation of thin samples by cleaving along the trigonal axis. This process is significantly lower in yield than epitaxial growth, but produces samples without defects or impurities. Similar to extracting graphene from bulk graphite samples, this is done by applying and removing adhesive tape from successively thinner samples. This procedure has been used to obtain flakes with a thickness of 1 nm. However, this process can leave significant amounts of adhesive residue on a standard Si/SiO substrate, which in turn obscure atomic force microscopy measurements and inhibit the placement of contacts on the substrate for purposes of testing. Common cleaning techniques such as oxygen plasma, boiling acetone and isopropyl alcohol are ineffective in removing residue. | 1 | Solid-state chemistry |
Mercury(II) iodide is a chemical compound with the molecular formula HgI. It is typically produced synthetically but can also be found in nature as the extremely rare mineral coccinite. Unlike the related mercury(II) chloride it is hardly soluble in water (<100 ppm). | 1 | Solid-state chemistry |
Nanoparticles present possible dangers, both medically and environmentally. Most of these are due to the high surface to volume ratio, which can make the particles very reactive or catalytic. They are also thought to aggregate on phospholipid bilayers and pass through cell membranes in organisms, and their interactions with biological systems are relatively unknown. However, it is unlikely the particles would enter the cell nucleus, Golgi complex, endoplasmic reticulum or other internal cellular components due to the particle size and intercellular agglomeration. A recent study looking at the effects of ZnO nanoparticles on human immune cells has found varying levels of susceptibility to cytotoxicity. There are concerns that pharmaceutical companies, seeking regulatory approval for nano-reformulations of existing medicines, are relying on safety data produced during clinical studies of the earlier, pre-reformulation version of the medicine. This could result in regulatory bodies, such as the FDA, missing new side effects that are specific to the nano-reformulation. However considerable research has demonstrated that zinc nanoparticles are not absorbed into the bloodstream in vivo.
Concern has also been raised over the health effects of respirable nanoparticles from certain combustion processes. Preclinical investigations have demonstrated that some inhaled or injected noble metal nano-architectures avoid persistence in organisms. As of 2013 the U.S. Environmental Protection Agency was investigating the safety of the following nanoparticles:
*Carbon nanotubes: Carbon materials have a wide range of uses, ranging from composites for use in vehicles and sports equipment to integrated circuits for electronic components. The interactions between nanomaterials such as carbon nanotubes and natural organic matter strongly influence both their aggregation and deposition, which strongly affects their transport, transformation, and exposure in aquatic environments. In past research, carbon nanotubes exhibited some toxicological impacts that will be evaluated in various environmental settings in current EPA chemical safety research. EPA research will provide data, models, test methods, and best practices to discover the acute health effects of carbon nanotubes and identify methods to predict them.
*Cerium oxide: Nanoscale cerium oxide is used in electronics, biomedical supplies, energy, and fuel additives. Many applications of engineered cerium oxide nanoparticles naturally disperse themselves into the environment, which increases the risk of exposure. There is ongoing exposure to new diesel emissions using fuel additives containing CeO nanoparticles, and the environmental and public health impacts of this new technology are unknown. EPA's chemical safety research is assessing the environmental, ecological, and health implications of nanotechnology-enabled diesel fuel additives.
*Titanium dioxide: Nano titanium dioxide is currently used in many products. Depending on the type of particle, it may be found in sunscreens, cosmetics, and paints and coatings. It is also being investigated for use in removing contaminants from drinking water.
*Nano Silver: Nano Silver is being incorporated into textiles, clothing, food packaging, and other materials to eliminate bacteria. EPA and the U.S. Consumer Product Safety Commission are studying certain products to see whether they transfer nano-size silver particles in real-world scenarios. EPA is researching this topic to better understand how much nano-silver children come in contact with in their environments.
*Iron: While nano-scale iron is being investigated for many uses, including "smart fluids" for uses such as optics polishing and as a better-absorbed iron nutrient supplement, one of its more prominent current uses is to remove contamination from groundwater. This use, supported by EPA research, is being piloted at a number of sites across the United States. | 0 | Colloidal Chemistry |
Brominated vegetable oil (BVO) is a complex mixture of plant-derived triglycerides that have been modified by atoms of the element bromine bonded to the fat molecules. Brominated vegetable oil is used to help emulsify citrus-flavored soft drinks, preventing them from separating during distribution. Brominated vegetable oil has been used by the soft drink industry since 1931, generally at a level of about 8 ppm.
Careful control of the type of oil used allows bromination of it to produce BVO with a specific density of 1.33 g/mL, which is 33% greater than water (1 g/mL). As a result, it can be mixed with less-dense flavoring agents such as citrus oil to produce an oil which matches the density of water or other products. The droplets containing BVO remain suspended in the water rather than separating and floating to the surface.
Alternative food additives used for the same purpose include sucrose acetate isobutyrate (SAIB, E444) and glycerol ester of wood rosin (ester gum, E445).
Similar iodinated oils have been used as contrast agents and for goiter prophylaxis in populations with low dietary iodine intake.
Brominated vegetable oil has the CAS number 8016-94-2 and the EC number 232-416-5. | 0 | Colloidal Chemistry |
Hazen is a Fellow of the American Association for the Advancement of Science.
The Mineralogical Society of America presented Hazen with the Mineralogical Society of America Award in 1982 and the Distinguished Public Service Medal in 2009. In 2016, he received its highest award, the Roebling Medal. He also served as Distinguished Lecturer and is a Past President of the Society. A mineral that was discovered in Mono Lake was named hazenite in his honor by Hexiong Yang, a former student of his.
In 1986, Hazen received the Ipatieff Prize, which the American Chemical Society awards in recognition of "outstanding chemical experimental work in the field of catalysis or high pressure".
For the book The Music Men, he and his wife Margaret received the Deems Taylor Award from the American Society of Composers, Authors and Publishers in 1989.
For his popular and educational science writing, Hazen received the E.A. Wood Science Writing Award from the American Crystallographic Association in 1998,
In 2012, the State Council of Higher Education for Virginia presented Hazen with its Outstanding Faculty Award.
Hazen has presented numerous named lectures at universities. He gave a Directorate for Biological Sciences Distinguished Lecture at the National Science Foundation in 2007, and was named the Sigma Xi Distinguished Lecturer for 2008–2010.
In 2019, Hazen was named a Fellow of the American Geophysical Union.
In 2021, Hazen was awarded the Medal of Excellence in Mineralogical Sciences from the International Mineralogical Association. | 1 | Solid-state chemistry |
Education:
* 1969: Cand scient. Organic Chemistry, University of Copenhagen
* 1973: Lic.Scient. (Chemistry), University of Copenhagen.
Academic Appointments:
* 1974–1984: Lecturer at the University of Copenhagen.
* 1984–1989: Research Professor at the University of Copenhagen
* 1989–1993: Professor of Organic Chemistry at the University of Copenhagen.
* 1993–2000: Head of the Department of Condensed Matter Physics and Chemistry. Risø
* 2001–2003: In charge of the Interdisciplinary Nanotechnology Programme, Risø
* 2001–2003: Temporary Head of The Danish Polymer Centre and the Polymer Department Risø
* 2004–2017: Professor of Chemistry at the University of Copenhagen (May 2004 – March 2017). Deputy Head of Department
Other:
* 2004: A. J. Heeger Endowed Chair, UCSB, Santa Barbara
Honours:
* 1983: Elected member of the Danish Academy of Natural Sciences
* 1984: Elected member of the Royal Danish Academy.
* 2002: Elected member of the French Academy of Sciences
Publications:
* Approximately 370 peer reviewed papers in Chemistry and Solid State Physics, 7 patents
Awards:
* 1981: The HN-prize
* 1986: The B.S. Friedmann-prize, University of California
* 1987: The Director Ib Henriksen's Foundation Research award
* 1990: The Macintosh Research award
* 1991: EPS Europhysics Prize
* 1991: The Hewlett Packard Europhysics prize
* 1997: The NKT scientific prize
* 2000: The EU Descartes prize
* 2008: The Hartmann Foundation memorial prize | 1 | Solid-state chemistry |
Counterion condensation is a phenomenon described by Manning's
theory (Manning 1969), which assumes that counterions can condense
onto polyions until the charged density between neighboring monomer charges
along the polyion chain is reduced below a certain critical value. In the model the
real polyion chain is replaced by an idealized line charge, where the polyion
is represented by a uniformly charged thread of zero radius, infinite
length and finite charge density, and the condensed counterion layer is
assumed to be in physical equilibrium with the ionic atmosphere surrounding
the polyion. The uncondensed mobile ions in the ionic atmosphere are treated
within the Debye–Hückel (DH) approximation. The
phenomenon of counterion condensation now takes place when the dimensionless
Coulomb coupling strength
where represents the Bjerrum length and
the distance between neighboring charged monomers.
In this case the Coulomb interactions dominate over
the thermal interactions and counterion condensation is favored. For many standard
polyelectrolytes, this phenomenon is relevant, since the
distance between neighboring monomer charges typically ranges between 2 and 3 Å and
7 Å in water.
The Manning theory states that the fraction of "condensed" counter ions is , where "condensed" means that the counter ions are located within the Manning radius .
At infinite dilution the Manning radius diverges and the actual concentration of ions close to the charged rod is reduced (in agreement with the law of dilution). | 1 | Solid-state chemistry |
Synthesis of gold nanoparticles has been investigated utilizing Fusarium, Neurospora, Verticillium, yeasts, and Aspergillus. Extracellular gold nanoparticle synthesis was demonstrated by Fusarium oxysporum, Aspergillus niger, and cytosolic extracts from Candida albican. Intracellular gold nanoparticle synthesis has been demonstrated by a Verticillum species, V. luteoalbum, | 0 | Colloidal Chemistry |
A betaine () in chemistry is any neutral chemical compound with a positively charged cationic functional group that bears no hydrogen atom, such as a quaternary ammonium or phosphonium cation (generally: onium ions), and with a negatively charged functional group, such as a carboxylate group that may not be adjacent to the cationic site. Historically, the term was reserved for trimethylglycine (TMG), which is involved in methylation reactions and detoxification of homocysteine. This is a modified amino acid consisting of glycine with three methyl groups serving as methyl donor for various metabolic pathways. | 0 | Colloidal Chemistry |
NbCl is produced by reduction of niobium(V) chloride with hydrogen, or just by heating.
Salt-free reduction of dimethoxyethane solution of NbCl with 1,4-disilyl-cyclohexadiene in the presence of 3-hexyne produces the coordination complex NbCl(dimethoxyethane)(3-hexyne):
: NbCl + CH(SiMe) + CEt + dme → NbCl(dme)(CEt) + CH + 2 MeSiCl
An impure dimethoxyethane (dme) adduct of niobium trichloride was produced by reduction of a dme solution of niobium pentachloride with tributyltin hydride:
:NbCl + 2 BuSnH + MeOCHCHOMe → NbCl(MeOCHCHOMe) + 2 BuSnCl | 1 | Solid-state chemistry |
Rüdorff and Ulrich Hofmann's work on graphite intercalation compound and sulfuric acid became an ancestor of lithium ion battery.
Rüdorff's team discovered the ternary oxide series (including LiVO and NaVO) in 1954 with a unique structure. The compounds with the same structural type are called rudorffites for this reason.
Rüdorff's work in 1965 on hosting lithium in titanium disulfide (TiS) inspired early efforts into using metal chalcogenides as battery cathode material. | 1 | Solid-state chemistry |
* 1990 Otto Hahn Medal (Max Planck Society)
* 1996 Prize of Angewandte Chemie
* 1997 Chemistry Lecturer Prize (Fonds der chemischen Industrie)
* 2014 Distinguished Professorship (RWTH Aachen University)
* 2015 Innovation Award (RWTH Aachen University)
* 2017 Egon Wiberg Lecture (Ludwig Maximilian University of Munich) | 1 | Solid-state chemistry |
Iron sulfides occur widely in nature in the form of iron–sulfur proteins.
As organic matter decays under low-oxygen (or hypoxic) conditions such as in swamps or dead zones of lakes and oceans, sulfate-reducing bacteria reduce various sulfates present in the water, producing hydrogen sulfide. Some of the hydrogen sulfide will react with metal ions in the water or solid to produce iron or metal sulfides, which are not water-soluble. These metal sulfides, such as iron(II) sulfide, are often black or brown, leading to the color of sludge.
Pyrrhotite is a waste product of the Desulfovibrio bacteria, a sulfate reducing bacteria.
When eggs are cooked for a long time, the yolk's surface may turn green. This color change is due to iron(II) sulfide, which forms as iron from the yolk reacts with hydrogen sulfide released from the egg white by the heat. This reaction occurs more rapidly in older eggs as the whites are more alkaline.
The presence of ferrous sulfide as a visible black precipitate in the growth medium peptone iron agar can be used to distinguish between microorganisms that produce the cysteine metabolizing enzyme cysteine desulfhydrase and those that do not. Peptone iron agar contains the amino acid cysteine and a chemical indicator, ferric citrate. The degradation of cysteine releases hydrogen sulfide gas that reacts with the ferric citrate to produce ferrous sulfide. | 1 | Solid-state chemistry |
Girolami has received numerous awards for his research, including the Office of Naval Research Young Investigator Award, a Sloan Foundation Fellowship, a Dreyfus Teacher-Scholar Award, and a University Scholar Award. He has been honored by UIUC with a Campus Award for Excellence in Graduate and Professional Teaching, for the introduction of a graduate class in inorganic chemistry covering group theory and electronic correlation methods. | 1 | Solid-state chemistry |
Lipids are a broad category of mid-sized molecules that are hydrophobic or amphipathic. In surfactant, two subcategories of lipids are relevant: phospholipids and sterols. Sterols are represented by cholesterol, which has an important role in the overall structure and motion of the lipids as a whole, but is vastly outnumbered by the phospholipids in surfactant.
DPPC (dipalmitoylphosphatidylcholine), as mentioned above, is a lipid with very useful stabilizing and compacting attributes. SP-B works primarily with this lipid, and moves it to the gas/fluid interface where it minimized surface tension. Essentially, DPPC is so important for lung function because it can shrink or expand to fit the space necessary, and a continually shrinking and expanding lung requires components like this.
Other lipids found commonly in surfactant include phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylethanolamine (PE), and phosphatidylserine (PS). | 0 | Colloidal Chemistry |
Sodium hydride is the chemical compound with the empirical formula NaH. This alkali metal hydride is primarily used as a strong yet combustible base in organic synthesis. NaH is a saline (salt-like) hydride, composed of Na and H ions, in contrast to molecular hydrides such as borane, silane, germane, ammonia, and methane. It is an ionic material that is insoluble in all solvents (other than molten sodium metal), consistent with the fact that H ions do not exist in solution. | 1 | Solid-state chemistry |
* American Physical Society Fellow (2020)
* American Chemical Society (ACS) Fellow (2016)
* Fellow of the Royal Society of Chemistry (2015)
*Electrochemical Society Member
*Materials Research Society Fellow (2011)
*American Association for the Advancement of Science Fellow (2000) | 1 | Solid-state chemistry |
Carbides can be generally classified by the chemical bonds type as follows:
# salt-like (ionic),
# covalent compounds,
# interstitial compounds, and
# "intermediate" transition metal carbides.
Examples include calcium carbide (CaC), silicon carbide (SiC), tungsten carbide (WC; often called, simply, carbide when referring to machine tooling), and cementite (FeC), each used in key industrial applications. The naming of ionic carbides is not systematic. | 1 | Solid-state chemistry |
Addition of a complexant like crown ether or [[2.2.2-Cryptand|[2.2.2-cryptand]] to a solution of [Na(NH)]e affords [Na (crown ether)]e or [Na(2,2,2-crypt)]e. Evaporation of these solutions yields a blue-black paramagnetic solid with the formula [Na(2,2,2-crypt)]e.
Most solid electride salts decompose above 240 K, although [CaAlO](e) is stable at room temperature. In these salts, the electron is delocalized between the cations. Electrides are paramagnetic, and are Mott insulators. Properties of these salts have been analyzed.
ThI and ThI have also been reported to be electride compounds. Similarly, Cerium#Chemistry|, , , and are all electride salts with a tricationic metal ion. | 1 | Solid-state chemistry |
In the last ten years, many experiments have been conducted numerically and analytically to validate the importance of nanofluids.
From the table 1 it is clear that nanofluid-based collector have a higher efficiency than a conventional collector. So, it is clear that we can improve conventional collector simply by adding trace amounts of nano-particles.
It has also been observed through numerical simulation that mean outlet temperature increase by increasing volume fraction of nanoparticles, length of tube and decreases by decreasing velocity. | 0 | Colloidal Chemistry |
Her initial research interests include Heusler compounds and related filled tetrahedral structure types, the design, synthesis and physical investigation of new quantum materials, and materials for energy technologies (solar cells, thermoelectrics, catalysis, spintronics). The physical investigations are executed on bulk material, thin films and artificial superstructures.
Her current research focuses on relativistic materials science. Felser, along with collaborators, developed the field of topological quantum chemistry, which involves the design, synthesis, and realization of new multifunctional materials guided by theory. In particular, she focuses on new materials for quantum technologies such as topological insulators, Weyl and Dirac semimetals, skyrmions, superconductors, new fermions, and new quasiparticles (axions, majorana, parafermions, etc.). | 1 | Solid-state chemistry |
Saline lakes are declining worldwide on every continent except Antarctica, mainly due to human causes, such as damming, diversions, and withdrawals. One of the largest factors causing this decline is agricultural irrigation. Among the most commonly cited examples is the Aral Sea, which has shrunk 90% in volume and 74% in area, which is mainly because of irrigation.
Another anthropogenic threat is climate change. Human-caused climate change is increasing temperature in many arid regions, drying soil, increasing evaporation, and reducing inflows to saline lakes.
Decline of saline lakes leads to many environmental problems, including human problems, such as toxic dust storms and air pollution, disrupted local water cycles, economic losses, loss of ecosystems, and more. It can even be more costly. For example, in the case of the decline of Owens Lake, dust stirred up from the dry lakebed has led to air quality higher than allowed by US-air quality standards. This has resulted in the city of Los Angeles spending $3.6 billion over the next 25 years to mitigate dust from the desiccated lakebed, which is more than the value of the diverted water.
Solutions to the decline of saline lakes can be multifaceted, and include water conservation and water budgeting, and mitigating climate change. | 1 | Solid-state chemistry |
Throughout human history, fungi have been utilized as a source of food and harnessed to ferment and preserve foods and beverages. In the 20th century, humans have learned to harness fungi to protect human health (antibiotics, anti-cholesterol statins, and immunosuppressive agents), while industry has utilized fungi for large scale production of enzymes, acids, and biosurfactants. With the advent of modern nanotechnology in the 1980s, fungi have remained important by providing a greener alternative to chemically synthesized nanoparticle. | 0 | Colloidal Chemistry |
NaH reduces certain main group compounds, but analogous reactivity is very rare in organic chemistry (see below). Notably boron trifluoride reacts to give diborane and sodium fluoride:
:6 NaH + 2 BF → BH + 6 NaF
Si–Si and S–S bonds in disilanes and disulfides are also reduced.
A series of reduction reactions, including the hydrodecyanation of tertiary nitriles, reduction of imines to amines, and amides to aldehydes, can be effected by a composite reagent composed of sodium hydride and an alkali metal iodide (NaH⋅MI, M = Li, Na). | 1 | Solid-state chemistry |
Magnetic nanochains are a new class of magnetoresponsive and superparamagnetic nanostructures with highly anisotropic shapes which can be manipulated using magnetic field and magnetic field gradient. Such nanochains consist of self-assembled nanoparticle clusters which are magnetically assembled and fixated into a chain. Among the various linking methods used are silica coating, polyacrylic acid (PAA) coating, tetraethoxysilane condensation, biotinylation or glucose decomposition. Typically, the primary building blocks of these nanostructures are individual superparamagnetic iron oxide nanoparticles (SPIONs). Nanoparticle clusters which are composed of a number of individual magnetic nanoparticles (ca. 100 SPIONs) are known as magnetic nanobeads with a diameter of 50–200 nanometers.
The force exerted on a particle depends on the strength, direction, and dynamics of the applied magnetic field as well as the position and orientation of local magnetic dipoles. Dynamic magnetic fields allow for the greatest range of control over chain shape. Of principal interest is the force exerted on the ends of the chain as a result of a dynamic field. The effect of Larmor precession with a row of magnetic colloids results in dynamic interactions dependent on the field precession angle. In fact, sweeping through the magic angle flips sign of the dipole-dipole interaction. In a field precessing quickly around the z-axis, the force exerted on the end of the chain is given by
where is the dipole moment, is the bead diameter, is the angular frequency of the field precession, is the rate of change of the filament path, is the viscous drag coefficient and is the unit vector of the plane perpendicular to the tangent of the filament curve. This produces a periodic magnetic force. However, under fast precession, the second term remains non-zero and scales with . At low , the magnetic torque dominates and the chain winds around itself. With a high , the bending modulus dominates the energetic landscape and filaments form branched gels with a field-dependent bulk modulus.
The applied load on a filament is generally limited by the polymer linking method. The elastic strain regime for a simple covalently linked filament is short and are taken as inextensible under most conditions. If tensile forces become too large, plastic deformation can occur usually resulting in bond breaking and polymer disentanglement. These irreversible changes can result in the permanent change in the bending modulus which ultimately effects the filament performance. | 0 | Colloidal Chemistry |
Dispersants are used to prevent formation of biofouling or biofilms in industrial processes. It is also possible to disperse bacterial slime and increase the efficiency of biocides. | 0 | Colloidal Chemistry |
Quantum tunnelling is among the central non-trivial quantum effects in quantum biology. Here it is important both as electron tunnelling and proton tunnelling. Electron tunnelling is a key factor in many biochemical redox reactions (photosynthesis, cellular respiration) as well as enzymatic catalysis. Proton tunnelling is a key factor in spontaneous DNA mutation.
Spontaneous mutation occurs when normal DNA replication takes place after a particularly significant proton has tunnelled. A hydrogen bond joins DNA base pairs. A double well potential along a hydrogen bond separates a potential energy barrier. It is believed that the double well potential is asymmetric, with one well deeper than the other such that the proton normally rests in the deeper well. For a mutation to occur, the proton must have tunnelled into the shallower well. The proton's movement from its regular position is called a tautomeric transition. If DNA replication takes place in this state, the base pairing rule for DNA may be jeopardised, causing a mutation. Per-Olov Lowdin was the first to develop this theory of spontaneous mutation within the double helix. Other instances of quantum tunnelling-induced mutations in biology are believed to be a cause of ageing and cancer. | 1 | Solid-state chemistry |
At a Christmas party in 2006, the biophysicist Harold Morowitz asked Hazen whether there were clay minerals during the Archean Eon. Hazen could not recall a mineralogist ever having asked whether a given mineral existed in a given era, and it occurred to him that no one had ever explored how Earths mineralogy changed over time. He worked on this question for a year with his closest colleague, geochemist Dimitri Sverjensky at Johns Hopkins University, and some other collaborators including a mineralogist, Robert Downs; a petrologist, John Ferry; and a geobiologist, Dominic Papineau. The result was a paper in American Mineralogist' that provided a new historical context to mineralogy that they called mineral evolution.
Based on a review of the literature, Hazen and his co-authors estimated that the number of minerals in the Solar System has grown from about a dozen at the time of its formation to over 4300 at present. (As of 2017, the latter number has grown to 5300.). They predicted that there was a systematic increase in the number of mineral species over time, and identified three main eras of change: the formation of the Solar System and planets; the reworking of crust and mantle and the onset of plate tectonics; and the appearance of life. After the first era, there were 250 minerals; after the second, 1500. The remainder were made possible by the action of living organisms, particularly the addition of oxygen to the atmosphere. This paper was followed over the next few years by several studies concentrating on one chemical element at a time and mapping out the first appearances of minerals involving each element. | 1 | Solid-state chemistry |
John Bannister Goodenough ( ; July 25, 1922 – June 25, 2023) was an American materials scientist, a solid-state physicist, and a Nobel laureate in chemistry. From 1986 he was a professor of Mechanical, Materials Science, and Electrical Engineering at the University of Texas at Austin. He is credited with
identifying the Goodenough–Kanamori rules of the sign of the magnetic superexchange in materials, with developing materials for computer random-access memory and with inventing cathode materials for lithium-ion batteries.
Goodenough was born in Jena, Germany, to American parents. During and after graduating from Yale University, Goodenough served as a U.S. military meteorologist in World War II. He went on to obtain his Ph.D. in physics at the University of Chicago, became a researcher at MIT Lincoln Laboratory, and later the head of the Inorganic Chemistry Laboratory at the University of Oxford.
Goodenough was awarded the National Medal of Science, the Copley Medal, the Fermi Award, the Draper Prize, and the Japan Prize. The John B. Goodenough Award in materials science is named for him. In 2019, he was awarded the Nobel Prize in Chemistry alongside M. Stanley Whittingham and Akira Yoshino; at 97 years old, he became the oldest Nobel laureate in history. From August 27, 2021, until his death, he was the oldest living Nobel Prize laureate. | 1 | Solid-state chemistry |
Large surface-to-volume ratios and low coordination of surface atoms are primary reasons for the unique reactivity of nanoclusters. Thus, nanoclusters are widely used as catalysts. Gold nanocluster is an excellent example of a catalyst. While bulk gold is chemically inert, it becomes highly reactive when scaled down to nanometer scale. One of the properties that govern cluster reactivity is electron affinity. Chlorine has highest electron affinity of any material in the periodic table. Clusters can have high electron affinity and nanoclusters with high electron affinity are classified as super halogens. Super halogens are metal atoms at the core surrounded by halogen atoms. | 0 | Colloidal Chemistry |
Unlike elemental boron whose combustion is incomplete through the glassy oxide layered impeding oxygen diffusion, magnesium diboride burns completely when ignited in oxygen or in mixtures with oxidizers. Thus magnesium boride has been proposed as fuel in ram jets. In addition the use of MgB in blast-enhanced explosives and propellants has been proposed for the same reasons. Most recently it could be shown that decoy flares containing magnesium diboride/Teflon/Viton display 30–60% increased spectral efficiency, E (J gsr), compared to classical Magnesium/Teflon/Viton(MTV) payloads.
An application of magnesium diboride to hybrid rocket propulsion has also been investigated, mixing the compound in paraffin wax fuel grains to improve mechanical properties and combustion characteristics. | 1 | Solid-state chemistry |
A disadvantage of using nanocrystals for drug delivery is nanocrystal stability. Instability problems of nanocrystalline structures derive from thermodynamic processes such as particle aggregation, amorphization, and bulk crystallization. Particles at the nanoscopic scale feature a relative excess of Gibbs free energy, due to their higher surface area to volume ratio. To reduce this excess energy, it is generally favorable for aggregation to occur. Thus, individual nanocrystals are relatively unstable by themselves and will generally aggregate. This is particularly problematic in top-down production of nanocrystals. Methods such as high-pressure homogenization and bead milling, tend to increase instabilities by increasing surface areas; to compensate, or as a response to high pressure, individual particles may aggregate or turn amorphous in structure. Such methods can also lead to the reprecipitation of the drug by surpassing the solubility beyond the saturation point (Ostwald ripening).
One method to overcome aggregation and retain or increase nanocrystal stability is by use of stabilizer molecules. These molecules, which interact with the surface of the nanocrystals and prevent aggregation via ionic repulsion or steric barriers between the individual nanocrystals, include surfactants and are generally useful for stabilizing suspensions of nanocrystals. Concentrations of surfactants that are too high, however, may inhibit nanocrystal stability and enhance crystal growth or aggregation. It has been shown that certain surfactants, upon reaching a critical concentration, begin to self-assemble into micelles, which then compete with nanocrystal surfaces for other surfactant molecules. With fewer surface molecules interacting with the nanocrystal surface, crystal growth and aggregation is reported to occur at increased amounts. Use of surfactant at optimal concentrations reportedly allows for higher stability, larger drug capacity as a carrier, and sustained drug release. In a study using PEG as a stabilizer was found that nanocrystals treated with PEG enhanced accumulation at tumor sites and had greater blood circulation, than those not treated with PEG.
Amorphization can occur in top-down methods of production. With different intramolecular arrangements, amorphization of nanocrystals leads to different thermodynamic and kinetic properties that affect drug delivery and kinetics. Transition to amorphous structures is reported to occur through production practices such as spray drying, lyophilization, and mechanical mechanisms, such as milling. This amorphization has been reportedly observed with or without the presence of stabilizer in a dry milling process. Using a wet milling process with surfactant, however significantly reduced amorphization, suggesting that solvent, in this case water, and surfactant could inhibit amorphization for some top-down production methods that otherwise reportedly facilitate amorphization. | 0 | Colloidal Chemistry |
Berzelius stated in 1810 that living things work by some mysterious "vital force", a hypothesis called vitalism. Vitalism had first been proposed by prior researchers, although Berzelius contended that compounds could be distinguished by whether they required any organisms in their synthesis (organic compounds) or whether they did not (inorganic compounds). However, in 1828, Friedrich Wöhler accidentally obtained urea, an organic compound, by heating ammonium cyanate. This showed that an organic compound such as urea could be prepared synthetically and not exclusively by living organisms. Berzelius corresponded with Wöhler on the urea synthesis findings. However, the notion of vitalism continued to persist, until further work on abiotic synthesis of organic compounds provided substantial evidence against vitalism. | 1 | Solid-state chemistry |
Omar M. Yaghi published the first paper of covalent organic frameworks (COFs) in 2005, reporting a series of 2D COFs. He reported the design and successful synthesis of COFs by condensation reactions of phenyl diboronic acid (CH[B(OH)]) and hexahydroxytriphenylene (CH(OH)). Powder X-ray diffraction studies of the highly crystalline products having empirical formulas (CHBO)·(CH) (COF-1) and CHBO (COF-5) revealed 2-dimensional expanded porous graphitic layers that have either staggered conformation (COF-1) or eclipsed conformation (COF-5). Their crystal structures are entirely held by strong bonds between B, C, and O atoms to form rigid porous architectures with pore sizes ranging from 7 to 27 Angstroms. COF-1 and COF-5 exhibit high thermal stability (to temperatures up to 500 to 600 °C), permanent porosity, and high surface areas (711 and 1590 square meters per gram, respectively). The synthesis of 3D COFs has been hindered by longstanding practical and conceptual challenges until it was first achieved in 2007 by Omar M. Yaghi
Yaghi is also known for the design and production of a new class of compounds known as zeolitic imidazolate frameworks (ZIFs). MOFs, COFs, ZIFs are noted for their extremely high surface areas ( for MOF-177) and very low crystalline densities ( for COF-108). Yaghi also pioneered molecular weaving, and synthesized the world’s first material woven at the atomic and molecular levels (COF-505).
He has been leading the effort in applying these materials in clean energy technologies including hydrogen and methane storage, carbon dioxide capture and storage, as well as harvesting water from desert air.
According to a Thomson Reuters analysis, Yaghi was the second most cited chemist in the world from 2000–2010. | 1 | Solid-state chemistry |
The concept of lattice energy was originally applied to the formation of compounds with structures like rocksalt (NaCl) and sphalerite (ZnS) where the ions occupy high-symmetry crystal lattice sites. In the case of NaCl, lattice energy is the energy change of the reaction
: Na (g) + Cl (g) → NaCl (s)
which amounts to −786 kJ/mol.
Some chemistry textbooks as well as the widely used CRC Handbook of Chemistry and Physics define lattice energy with the opposite sign, i.e. as the energy required to convert the crystal into infinitely separated gaseous ions in vacuum, an endothermic process. Following this convention, the lattice energy of NaCl would be +786 kJ/mol. Both sign conventions are widely used.
The relationship between the lattice energy and the lattice enthalpy at pressure is given by the following equation:
where is the lattice energy (i.e., the molar internal energy change), is the lattice enthalpy, and the change of molar volume due to the formation of the lattice. Since the molar volume of the solid is much smaller than that of the gases, . The formation of a crystal lattice from ions in vacuum must lower the internal energy due to the net attractive forces involved, and so . The term is positive but is relatively small at low pressures, and so the value of the lattice enthalpy is also negative (and exothermic). | 1 | Solid-state chemistry |
Many superconductors are non-stoichiometric. For example, yttrium barium copper oxide, arguably the most notable high-temperature superconductor, is a non-stoichiometric solid with the formula YBaCuO. The critical temperature of the superconductor depends on the exact value of x. The stoichiometric species has x = 0, but this value can be as great as 1. | 1 | Solid-state chemistry |
One major disadvantage of phosphorene is its limited air-stability. Composed of hygroscopic phosphorus and with extremely high surface-to-volume ratio, phosphorene reacts with water vapor and oxygen assisted by visible light to degrade within the scope of hours. Through the degradation process, phosphorene (solid) reacts with oxygen/water to develop liquid phase acid bubbles on the surface, and finally evaporate (vapor) to fully vanish (S-B-V degradation) and severely reducing overall quality. | 1 | Solid-state chemistry |
The electrical resistivity increases abruptly at the phase transition point around 104 °C, with the precise temperature depending on the stoichiometry. | 1 | Solid-state chemistry |
In solid-state physics, the electronic band structure (or simply band structure) of a solid describes the range of energy levels that electrons may have within it, as well as the ranges of energy that they may not have (called band gaps or forbidden bands).
Band theory derives these bands and band gaps by examining the allowed quantum mechanical wave functions for an electron in a large, periodic lattice of atoms or molecules. Band theory has been successfully used to explain many physical properties of solids, such as electrical resistivity and optical absorption, and forms the foundation of the understanding of all solid-state devices (transistors, solar cells, etc.). | 1 | Solid-state chemistry |
The fluorinated surfactants or fluorosurfactants subgroup has a fluorinated "tail" and a hydrophilic "head" and are thus considered surfactants. These are more effective at reducing the surface tension of water than comparable hydrocarbon surfactants. They include the perfluorosulfonic acids, such as perfluorooctanesulfonic acid (PFOS), and the perfluorocarboxylic acids like perfluorooctanoic acid (PFOA).
Fluorosurfactants are surfactants containing fluorocarbon chains such as those in PFASs. Their hydrophobic nature can reduce the surface tension of water below what is attainable by using hydrocarbon surfactants, so fluorosurfactants tend to concentrate at the liquid-air interface. Fluorocarbons are both lipophobic and hydrophobic, which allows them to repel both oil and water. Their lipophobicity results from the relative lack of London dispersion forces when compared to hydrocarbons, a consequence of fluorines large electronegativity and small bond length, which reduce the polarizability of the surfactants fluorinated molecular surface. Fluorosurfactants are more stable and fit for harsher conditions than hydrocarbon surfactants because of the stability of the carbon–fluorine bond. Perfluorinated surfactants persist in the environment for the same reason. | 0 | Colloidal Chemistry |
Alivisatos is the founding scientist of Quantum Dot Corporation, a company that makes crystalline nanoscale tags that are used in the study of cell behavior. (Quantum Dot is now part of Life Technologies.) He also founded the nanotechnology company Nanosys, and Solexant, a photovoltaic start-up that has since restarted as Siva Power. His research has led to the development of applications in range of industries, including bioimaging (for example, the use of quantum dots for luminescent labeling of biological tissue); display technologies (his quantum dot emissive film is found in the Kindle Fire HDX tablet); and renewable energy (solar applications of quantum dots). | 1 | Solid-state chemistry |
In addition to gold and silver, Fusarium oxysporum has been used to synthesize zirconia, titanium, cadmium sulfide and cadmium selenide nanosize particles. Cadmium sulfide nanoparticles have also been synthesized by Trametes versicolor, Schizosaccharomyces pombe, and Candida glabrata. The white-rot fungus Phanerochaete chrysosporium has also been demonstrated to be able to synthesize elemental selenium nanoparticles. | 0 | Colloidal Chemistry |
Tin(IV) oxide can be used as a polishing powder, sometimes in mixtures also with lead oxide, for polishing glass, jewelry, marble and silver. Tin(IV) oxide for this use is sometimes called as "putty powder" or "jeweler's putty". | 1 | Solid-state chemistry |
Higher sulfur oxides are a group of chemical compounds with the formula SO where x lies between 0 and 1. They contain peroxo (O−O) groups, and the oxidation state of sulfur is +6 as in SO.
Monomeric SO can be isolated at low temperatures (below 78 K) following the reaction of SO and atomic oxygen or photolysis of SO–ozone mixtures. The favoured structure is:
Colourless polymeric condensates are formed in the reaction of gaseous SO or SO with O in a silent electric discharge. The structure of the polymers is based on β-SO (one of the three forms of solid SO) with oxide bridges (−O−) replaced randomly by peroxide bridges(−O−O−). As such these compounds are non-stoichiometric. | 1 | Solid-state chemistry |
Molybdenite is an important ore of molybdenum, and is the most common source of the metal. While molybdenum is rare in the Earths crust, molybdenite is relatively common and easy to process, and accounts for much of the metals economic viability. Molybdenite is purified by froth flotation, and then oxidized to form soluble molybdate. Reduction of ammonium molybdate yields pure molybdenum metal, which is used for fertilizer, as a catalyst, and in battery electrodes. By far the most common use of molybdenum is as an alloy with iron. Ferromolybdenum is an important component of high strength and corrosion-resistant steel. | 1 | Solid-state chemistry |
Anthony W. Czarnik (born 1957) is an American chemist and inventor. He is best known for pioneering studies in the field of fluorescent chemosensors and co-founding Illumina, Inc., a biotechnology company in San Diego. Czarnik was also the founding editor of ACS Combinatorial Science. He currently serves as an adjunct visiting professor at the University of Nevada, Reno. | 1 | Solid-state chemistry |
A unilamellar liposome is a spherical liposome, a vesicle, bounded by a single bilayer of an amphiphilic lipid or a mixture of such lipids, containing aqueous solution inside the chamber. Unilamellar liposomes are used to study biological systems and to mimic cell membranes, and are classified into three groups based on their size: small unilamellar liposomes/vesicles (SUVs) that with a size range of 20–100 nm, large unilamellar liposomes/vesicles (LUVs) with a size range of 100–1000 nm and giant unilamellar liposomes/vesicles (GUVs) with a size range of 1–200 µm. GUVs are mostly used as models for biological membranes in research work. Animal cells are 10–30 µm and plant cells are typically 10–100 µm. Even smaller cell organelles such as mitochondria are typically 1–2 µm. Therefore, a proper model should account for the size of the specimen being studied. In addition, the size of vesicles dictates their membrane curvature which is an important factor in studying fusion proteins. SUVs have a higher membrane curvature and vesicles with high membrane curvature can promote membrane fusion faster than vesicles with lower membrane curvature such as GUVs.
The composition and characteristics of the cell membrane varies in different cells (plant cells, mammalian cells, bacterial cells, etc). In a membrane bilayer, often the composition of the phospholipids is different between the inner and outer leaflets. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and sphingomyelin are some of the most common lipids most animal cell membranes. These lipids are widely different in charge, length, and saturation state. The presence of unsaturated bonds (double bonds) in lipids for example, creates a kink in acyl chains which further changes the lipid packing and results in a looser packing. Therefore, the composition and sizes of the unilamellar liposomes must be chosen carefully based on the subject of the study.
Each lipid bilayer structure is comparable to lamellar phase lipid organization in biological membranes, in general. In contrast, multilamellar liposomes (MLVs), consist of many concentric amphiphilic lipid bilayers analogous to onion layers, and MLVs may be of variable sizes up to several micrometers. | 0 | Colloidal Chemistry |
In conjunction with vanadium oxide, it is used as a catalyst for the oxidation of aromatic compounds in the synthesis of carboxylic acids and acid anhydrides. | 1 | Solid-state chemistry |
When is small in front of the size of the regular islands, the fine structure of the classical phase space plays a key role in tunnelling. In particular the two symmetric tori are coupled "via a succession of classically forbidden transitions across nonlinear resonances" surrounding the two islands. | 1 | Solid-state chemistry |
While at Parke-Davis Pharmaceutical Research, a division of Warner-Lambert Company, Czarnik directed research and reported the first use of automation for the synthesis of compound “libraries”—large, organized collections of compounds. He became founding editor of the American Chemical Society’s Journal of Combinatorial Chemistry and led research into the use of Rf ID tags for directed sorting for use in compound library synthesis. | 1 | Solid-state chemistry |
* 2023: EPS CMD Europhysics Prize
* 2022: Member of the Academy od Sciences and Literature
* 2002: Blaise Pascal Medal of the European Academy of Sciences
* 2022: Liebig commemorative coin of the GDCh (Gesellschaft Deutscher Chemiker)
* 2022: Max Born Medal and Prize of the German Physical Society (DPG) and the British Institute of Physics (IOP)
* 2021: International Member of National Academy of Science (NAS), US
* 2020: International Member of National Academy of Engineering (NAE), US
* 2019: APS James C. McGroddy Prize for New Materials with Bernevig and Dai
* 2018: Member of the German National Academy of Sciences Leopoldina
* 2016: Elected fellow of the IEEE (magnetic society)
* 2015: Tsungming Tu Award
* 2014: Alexander M. Cruickshank Lecturer Award
* 2013: Elected American Physical Society (APS) fellow (Division of Condensed Matter Physics)
* 2010: Nakamura Lecture Award of the University of California Santa Barbara
* 2001: Order of Merit (Landesverdienstorden) of the federal state Rhineland-Palatinate for the foundation of the first NAT-LAB for school students at the University Mainz with a focus in female school students
She is the chairwoman of a German Research Foundation research group. She was a member of the 13th Bundesversammlung (Germany). | 1 | Solid-state chemistry |
Polyvinylcarbazole (PVK) is a temperature-resistant thermoplastic polymer produced by radical polymerization from the monomer N-vinylcarbazole. It is a photoconductive polymer and thus the basis for photorefractive polymers and organic light-emitting diodes. | 1 | Solid-state chemistry |
* Bibliography:
* Goubeau, Josef. (1961) "Wilhelm Klemm." In Zeitschrift für Elektrochemie. Berichte der Bunsengesellschaft für Physikalische Chemie. 65, p. 105.
* King RB 2004, The metallurgists periodic table and the Zintl-Klemm concept', in DH Rouvray DH & RB King (eds), The periodic table: into the 21st century, Institute of Physics Publishing, Philadelphia, , pp. 189–206.
* Miller GJ, Schmidt MW, Wang F & You T-S 2011, Quantitative Advances in the Zintl-Klemm Formalism, in TF Fässler (ed), Zintl Phases: Principles and Recent Developments, Springer-Verlag, Berlin, pp. 1 56,
* Klemm W 1950, Einige probleme aus der physik und der chemie der halbmetalle und der metametalle, Angewandte Chemie, vol. 62, no. 6, pp. 133–42 | 1 | Solid-state chemistry |
Mercury(II) iodide is used for preparation of Nessler's reagent, used for detection of presence of ammonia.
Mercury(II) iodide is a semiconductor material, used in some x-ray and gamma ray detection and imaging devices operating at room temperatures.
In veterinary medicine, mercury(II) iodide is used in blister ointments in exostoses, bursal enlargement, etc.
It can appear as a precipitate in many reactions. | 1 | Solid-state chemistry |
The underlying principle is to merge pores of different sizes into a material with a large surface area (thanks to smaller pores), which in turn allows efficient molecular transport (which requires larger pores). The process used to produce these materials is a combination of the replication method, typically used to produce large-pore foams, and the selective dissolution method, generally used to manufacture small-pore foams.
Ag foams with hierarchical porous structures are prepared by the following three-step method:
(i) Packing large spherical NaCl particles to create a hard template, with a distinct perform network of negative space. Then this network is filled with liquid Al-25Ag.
(ii) Removing the NaCl template by water dissolution to form Al−25Ag macro-porous foam.
(iii) Dissolving the Al-rich phase by a chemical attack with aqueous solutions of HCl or NaOH to form the final Ag foam. This creates the nanoscale pores of the foam. | 0 | Colloidal Chemistry |
In 1945, Kê started research on internal friction and anelastic properties in metals at the University of Chicago where he accomplished advanced studies of grain-boundary relaxation and non-linear anelastic relaxation associated to interactions between point defects and dislocations. This work continued after he returned to China in 1949 where he made further progress. The Kê-type torsion pendulum bears his name, as well as the Kê grain-boundary internal friction peak. Kê also proposed the Kê grain-boundary model for disordered atomic groups. Kê also participated in the Manhattan Project and the Long-Range Radar projects. | 1 | Solid-state chemistry |
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are used as thickeners, components of some lubricants, and precursors to catalysts.
When used for cleaning, soap solubilizes particles and grime, which can then be separated from the article being cleaned. In hand washing, as a surfactant, when lathered with a little water, soap kills microorganisms by disorganizing their membrane lipid bilayer and denaturing their proteins. It also emulsifies oils, enabling them to be carried away by running water.
Soap is created by mixing fats and oils with a base. Humans have used soap for millennia; evidence exists for the production of soap-like materials in ancient Babylon around 2800 BC. | 1 | Solid-state chemistry |
*G. W. Scott Blair (1938) An Introduction to Industrial Rheology (Churchill, London)
*G. W. Scott Blair (1949) A Survey of General and Applied Rheology (Pitman, London)
*G. W. Scott Blair (1950) Measurements of Mind and Matter (Dobson, London)
*G. W. Scott Blair (1953) Foodstuffs : their plasticity, fluidity and consistency (Amsterdam)
*G. W. Scott Blair & M. Reiner (1957) Agricultural Rheology (Routledge & Kegan Paul, London)
*G. W. Scott Blair (1969) Elementary Rheology (Academic Press, London)
*G. W. Scott Blair (1974) An Introduction to Biorheology (Elsevier, Oxford) | 0 | Colloidal Chemistry |
Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogens melting point of . It was collected for the first time by James Dewar in 1899 and published with the title "Sur la solidification de lhydrogène" (English: On the freezing of hydrogen) in the Annales de Chimie et de Physique, 7th series, vol. 18, Oct. 1899. Solid hydrogen has a density of 0.086 g/cm making it one of the lowest-density solids. | 1 | Solid-state chemistry |
Tungsten disilicide can react violently with substances such as strong acids, fluorine, oxidizers, and interhalogens. | 1 | Solid-state chemistry |
The Michigan PFAS Action Response Team (MPART) was launched in 2017 and is the first multi-agency action team of its kind in the nation. Agencies representing health, environment, and other branches of state government have joined together to investigate sources and locations of PFAS contamination in the state, take action to protect people's drinking water, and keep the public informed.
Groundwater is tested at locations throughout the state by various parties to ensure safety, compliance with regulations, and proactively detect and remedy potential problems. In 2010, the Michigan Department of Environmental Quality (MDEQ) discovered levels of PFASs in groundwater monitoring wells at the former Wurtsmith Air Force Base. As additional information became available from other national testing, Michigan expanded its investigations into other locations where PFAS compounds were potentially used.
In 2018, the MDEQs Remediation and Redevelopment Division (RRD) established cleanup criteria for groundwater used as drinking water of 70 ppt of PFOA and PFOS, individually or combined. The RRD staff are responsible for implementing these criteria as part of their ongoing efforts to clean up sites of environmental contamination. The RRD staff are the lead investigators at most of the PFAS sites on the MPART website and also conduct interim response activities, such as coordinating bottled water or filter installations with local health departments at sites under investigation or with known PFAS concerns. Most of the groundwater sampling at PFAS sites under RRDs lead is conducted by contractors familiar with PFAS sampling techniques. The RRD also has a Geologic Services Unit, with staff who install monitoring wells and are also well versed with PFAS sampling techniques.
The MDEQ has been conducting environmental clean-up of regulated contaminants for decades. Due to the evolving nature of PFAS regulations as new science becomes available, the RRD is evaluating the need for regular PFAS sampling at Superfund sites and is including an evaluation of PFAS sampling needs as part of a Baseline Environmental Assessment review.
Earlier in 2018, the RRD purchased lab equipment that will allow the MDEQ Environmental Lab to conduct analyses of certain PFAS samples. (Currently, most samples are shipped to one of the few labs in the country that conduct PFAS analysis, in California, although private labs in other parts of the country, including Michigan, are starting to offer these services.) As of August 2018, RRD has hired additional staff to work on developing the methodology and conducting PFAS analyses.
In 2020 Michigan Attorney General Dana Nessel filed a lawsuit against 17 companies, including 3M, Chemours, and DuPont, for hiding known health and environmental risks from the state and its residents. Nessels complaint identifies 37 sites with known contamination. The Michigan Department of Environment, Great Lakes, and Energy introduced some of the strictest drinking water standards in the country for PFAS, setting maximum contaminant levels (MCLs) for PFOA and PFOS to 8 and 16 ppt respectively (down from previous existing groundwater cleanup standards of 70 ppt for both), and introducing MCLs for 5 other previously unregulated PFAS compounds, limiting PFNA to 6 ppt, PFHxA to 400,000 ppt, PFHxS to 51 ppt, PFBS to 420 ppt and HFPO-DA to 370 ppt. The change adds 38 additional sites to the states list of known PFAS contaminated areas, bringing the total number of known sites to 137. About half of these sites are landfills and 13 are former plating facilities.
In 2022 PFOS was found in beef produced at a Michigan farm: the cattle had been fed crops fertilized with contaminated biosolids. State agencies issued a consumption advisory, but did not order a recall, because there currently is no PFOS contamination in beef government standards. | 0 | Colloidal Chemistry |
Dipankar Das Sarma was born on 15 September 1955 in Kolkata, in West Bengal. He did a five-year integrated masters course in Physics from the Indian Institute of Technology, Kanpur in 1977 and enrolled for research at the Indian Institute of Science, (IISc) Bengaluru from where he secured his PhD in 1982 under the tutelage of renowned solid state chemist, C. N. R. Rao. He worked as a research associate at IISc for one year (1982–83), moved to Forschungszentrum Jülich, (Jülich Research Centre) Germany as a guest scientist in 1984 and returned to IISc as a lecturer in 1986. He stayed at IISc where he became the assistant professor in 1989, associate professor in 1993 and a professor in 1999. He remains a professor at Solid State and Structural Chemistry Unit at the institution. He also served as a visiting professor at the University of Tokyo (2001–02) and at the Istituto di Struttura della Materia, CNR at their Rome and Trieste centres in 2002. | 1 | Solid-state chemistry |
An example of an organic ferromagnetic polymer is presented in an article by Yuwei Ma et al.: by cutting with ceramic scissors or stretching a piece of Teflon tape, a network of strongly coupling dangling bonds arises on surfaces where the polymer was broken (from cutting or in strain-induced cavities). In the case of weak structural deformation, where only very few dangling bonds are formed, the coupling is very weak and a paramagnetic signal is measured in EPR analysis.
Annealing Teflon under an argon atmosphere at 100 °C to 200 °C results also in ferromagnetic properties. However, annealing close to the melting temperature of Teflon makes the ferromagnetism disappear.
Under longer air exposure, the magnetization is reduced due to adsorbed water molecules. It also appeared that no ferromagnetism would develop under annealing Teflon under water steam or cutting in a H environment. | 1 | Solid-state chemistry |
C12-15 pareth-12 (INCI name) is an emulsifier and surfactant commonly used in cosmetics formulations. It is a polyethylene glycol ether formed by combining synthetic C–C fatty alcohols with 12 moles of ethylene oxide.
According to the INCI, "the term Pareth applies to ethoxylated paraffinic alcohols containing both even- and odd-carbon chain length fractions." | 0 | Colloidal Chemistry |
Brock completed her undergraduate degree in chemistry at the University of Washington. She was a graduate student at the University of California, Davis, where she investigated structure-property relationships in pnictide oxide compounds under the supervision of Susan M. Kauzlarich. During her doctorate she made use of powder diffraction and magnetic susceptibility measurements. Brock was a postdoctoral research associate at the University of Connecticut where she worked with Steven Suib on the use of manganese oxide nanocrystalline materials. | 1 | Solid-state chemistry |
The main directions of scientific research are mechanochemistry of organic and inorganic substances, mineral and renewable raw materials, reactivity of solids, modification of new structures and materials, mechanisms of solid-phase transformations (including conditions of high pressures and temperatures, combustion and explosion), development of research methods for fast processes using synchrotron radiation etc. | 1 | Solid-state chemistry |
When the interfacial areas are large, the amount of surfactant at the interface cannot be neglected. If, for example, air bubbles are introduced into a solution of a surfactant above CMC, these bubbles, as they rise to the surface, remove surfactants from the bulk to the top of the solution creating a foam column and thus reducing the concentration in bulk to below CMC. This is one of the easiest methods to remove surfactants from effluents (see foam flotation). Thus in foams with sufficient interfacial area are devoid of micelles. Similar reasoning holds for emulsions.
The other situation arises in detergents. One initially starts off with concentrations greater than CMC in water and on adding fabric with large interfacial area, the surfactant concentration drops below CMC and no micelles remain at equilibrium. Therefore, the solubilization plays a minor role in detergents. Removal of oily soil occurs by modification of the contact angles and release of oil in the form of emulsion.
In petroleum industry, CMC is considered prior to injecting surfactant in reservoir regarding enhanced oil recovery (EOR) application. Below the CMC point, interfacial tension between oil and water phase is no longer effectively reduced. If the concentration of the surfactant is kept a little above the CMC, the additional amount covers the dissolution with existing brine in the reservoir. It is desired that the surfactant will work at the lowest interfacial tension (IFT). | 0 | Colloidal Chemistry |
* 1967: Marlow Medal by the Faraday Society of England
* 1968: Shanti Swarup Bhatnagar Prize for Science and Technology in Chemical Science
* 2000: Centenary Medal of the Royal Society of Chemistry, London
* 2000: Hughes Medal by the Royal Society
* 2004: India Science Award
* 2005: Dan David Prize from Tel Aviv University shared with George Whitesides and Robert Langer.
* 2008: Abdus Salam Medal by The World Academy of Sciences (TWAS)
* 2009: Royal Medal by the Royal Society
* 2010: August-Wilhelm-von-Hofmann Medal by the German Chemical Society
* 2017: The Von Hippel Award by the Materials Research Society
* 2021: International ENI award 2020 for research in renewable energy sources and energy storage, also called the Energy Frontier award | 1 | Solid-state chemistry |
Dispersants can be used to dissipate oil slicks. They may rapidly disperse large amounts of certain oil types from the sea surface by transferring it into the water column. They will cause the oil slick to break up and form water-soluble micelles that are rapidly diluted. Then effectively spread throughout a larger volume of water than the surface from where the oil was dispersed. They can also delay the formation of persistent oil-in-water emulsions. However, laboratory experiments showed that dispersants increased toxic hydrocarbon levels in fish by a factor of up to 100 and may kill fish eggs.
Dispersant Corexit 9527 was for example used to disperse an oil slick in the Gulf of Mexico in 1979 (Ixtoc) over one thousand square miles of sea. The same dispersant was also used in an attempt to clean up the Exxon Valdez oil spill in 1989, though its use was discontinued as there was not enough wave action to mix the dispersant with the oil in the water. During the Deepwater Horizon oil spill in 2010, unprecedented amounts of the dispersants Corexit 9500 and 9527 were used (approximately 7 million liters). | 0 | Colloidal Chemistry |
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