text
stringlengths 105
19k
| label
int64 0
1
| label_text
stringclasses 2
values |
|---|---|---|
NaH can ignite spontaneously in air. It also reacts vigorously with water or humid air to release hydrogen, which is very flammable, and sodium hydroxide (NaOH), a quite corrosive base. In practice, most sodium hydride is sold as a dispersion in mineral oil, which can be safely handled in air. Although sodium hydride is widely used in DMSO, DMF or DMAc for SN2 type reactions there have been many cases of fires and/or explosions from such mixtures. | 1 | Solid-state chemistry |
In computational chemistry, a dangling bond generally represents an error in structure creation, in which an atom is inadvertently drawn with too few bonding partners, or a bond is mistakenly drawn with an atom at only one end. | 1 | Solid-state chemistry |
Sodium laureth sulfate, or sodium lauryl ether sulfate (SLES), is a detergent and surfactant found in many personal care products (soaps, shampoos, toothpastes, etc.). It is an inexpensive and effective foamer. Sodium lauryl sulfate (also known as sodium dodecyl sulfate or SDS) and ammonium lauryl sulfate (ALS) are commonly used alternatives to SLES in consumer products. | 0 | Colloidal Chemistry |
Acoustic foam is a lightweight material made from polyurethane (either polyether or polyester) or extruded melamine foam. It is usually cut into tiles. One surface of these tiles often features pyramid, cone, wedge, or uneven cuboid shapes. Acoustic foam tiles are suited to placing on sonically reflective surfaces to act as sound absorbers, thus enhancing or changing the sound properties of a room.
This type of sound absorption is different from soundproofing, which is typically used to keep sound from escaping or entering a room rather than changing the properties of sound within the room itself.
Acoustic foam panels typically suppress reverberations in the mid and high frequencies. To deal with lower frequencies, much thicker pieces of acoustic foam (often in metal or wood enclosures) can be placed in the corners of a room and are called acoustic foam bass traps. | 0 | Colloidal Chemistry |
Miguel A. García-Garibay is a professor of chemistry and biochemistry and the dean of physical sciences at University of California, Los Angeles (UCLA). His research focuses on solid state organic chemistry, photochemistry and spectroscopy, artificial molecular machines, and mesoscale phenomena. | 1 | Solid-state chemistry |
Biosurfactant usually refers to surfactants of microbial origin. Most of the biosurfactants produced by microbes are synthesized extracellularly and many microbes are known to produce biosurfactants in large relative quantities. Some are of commercial interest. As a secondary metabolite of microorganisms, biosurfactants can be processed by the cultivation of biosurfactant producing microorganisms in the stationary phase on many sorts of low-priced substrates like biochar, plant oils, carbohydrates, wastes, etc. High-level production of biosurfactants can be controlled by regulation of environmental factors and growth circumstances. | 0 | Colloidal Chemistry |
Asphalt modification through nanoparticles can be considered as an interesting low-cost technique in asphalt pavement engineering providing novel perspectives in making asphalt materials more durable. | 0 | Colloidal Chemistry |
In 1959, physicist Richard Feynman gave a talk titled “There’s Plenty of Room at the Bottom" to the American Physical Society. He imagined a world in which “we could arrange atoms one by one, just as we want them.” This idea set the stage for the bottom-up synthesis approach in which constituent components interact to form higher-ordered structures in a controllable manner. The study of self-assembly of nanoparticles began with recognition that some properties of atoms and molecules enable them to arrange themselves into patterns. A variety of applications where the self-assembly of nanoparticles might be useful. For example, building sensors or computer chips.
Definition
Self-assembly is defined as a process in which individual units of material associate with themselves spontaneously into a defined and organized structure or larger units with minimal external direction. Self-assembly is recognized as a highly useful technique to achieve outstanding qualities in both organic and inorganic nanostructures.
According to George M. Whitesides, "Self-assembly is the autonomous organization of components into patterns or structures without human intervention." Another definition by Serge Palacin & Renaud Demadrill is "Self-assembly is a spontaneous and reversible process that brings together in a defined geometry randomly moving distinct bodies through selective bonding forces."
Importance
To commemorate the 125th anniversary of Science magazine, 25 urgent questions were asked for scientists to solve, and the only one that relates to chemistry is“How Far Can We Push Chemical Self-Assembly?” Because self-assembly is the only approach for building a wide variety of nanostructures, the need for increasing complexity is growing. To learn from nature and build the nanoworld with noncovalent bonds, more research is needed in this area. Self assembly of nanomaterials is currently considered broadly for nano-structuring and nano-fabrication because of its simplicity, versatility and spontaneity. Exploiting the properties of the nano assembly holds promise as a low-cost and high-yield technique for a wide range of scientific and technological applications and is a key research effort in nanotechnology, molecular robotics, and molecular computation. A summary of benefits of self-assembly in fabrication is listed below:
*Self-assembly is a scalable and parallel process which can involve large numbers of components in a short timeframe.
*Can result in structural dimensions across orders of magnitude, from nanoscale to macroscale.
*Is relatively inexpensive compared to the top-down assembly approach, which often consumes large amounts of finite resources.
*Natural processes that drive self-assembly tend to be highly reproducible. The existence of life is strongly dependent on the reproducibility of self-assembly.
Challenges
There exist several outstanding challenges in self-assembly, due to a variety of competing factors. Currently self-assembly is difficult to control on large scales, and to be widely applied we will need to ensure high degrees of reproducibility at these scales. The fundamental thermodynamic and kinetic mechanisms of self-assembly are poorly understood - the basic principles of atomistic and macroscale processes can be significantly different than those for nanostructures. Concepts related to thermal motion and capillary action influence equilibrium timescales and kinetic rates that are not well defined in self-assembling systems.
Top-down vs bottom-up synthesis
The top-down approach is breaking down of a system into small components, while bottom-up is assembling sub-systems into larger system. A bottom-up approach for nano-assembly is a primary research target for nano-fabrication because top down synthesis is expensive (requiring external work) and is not selective on very small length scales, but is currently the primary mode of industrial fabrication. Generally, the maximum resolution of the top-down products is much coarser than those of bottom-up; therefore, an accessible strategy to bridge "bottom-up" and "top-down", is realizable by the principles of self-assembly. By controlling local intermolecular forces to find the lowest-energy configuration, self-assembly can be guided by templates to generate similar structures to those currently fabricated by top-down approaches. This so-called bridging will enable fabrication of materials with the fine resolution of bottom-up methods and the larger range and arbitrary structure of top-down processes. Furthermore, in some cases components are too small for top-down synthesis, so self-assembly principles are required to realize these novel structures.
Classification
Nanostructures can be organized into groups based on their size, function, and structure; this organization is useful to define the potential of the field.
By size
Among the more sophisticated and structurally complex nanostructures currently available are organic macromolecules, wherein their assembly relies on the placement of atoms into molecular or extended structures with atomic-level precision. It is now known that organic compounds can be conductors, semiconductors, and insulators, thus one of the main opportunities in nanomaterials science is to use organic synthesis and molecular design to make electronically useful structures. Structural motifs in these systems include colloids, small crystals, and aggregates on the order of 1-100 nm.
By function
Nanostructured materials can also be classed according to their functions, for example nanoelectronics and information technology (IT). Lateral dimensions used in information storage are shrinking from the micro- to the nanoscale as fabrication technologies improve. Optical materials are important in the development of miniaturized information storage because light has many advantages for storage and transmission over electronic methods. Quantum dots - most commonly CdSe nanoparticles having diameters of tens of nm, and with protective surface coatings - are notable for their ability to fluoresce over a broad range of the visible spectrum, with the controlling parameter being size.
By structure
Certain structural classes are especially relevant to nanoscience. As the dimensions of structures become smaller, their surface area-to-volume ratio increases. Much like molecules, nanostructures at small enough scales are essentially "all surface". The mechanical properties of materials are strongly influenced by these surface structures. Fracture strength and character, ductility, and various mechanical moduli all depend on the substructure of the materials over a range of scales. The opportunity to redevelop a science of materials that are nanostructured by design is largely open. | 0 | Colloidal Chemistry |
The structure consists of a peptide loop of seven amino acids (L-glutamic acid, L-leucine, D-leucine, L-valine, L-aspartic acid, D-leucine, and L-leucine) and a β-hydroxy fatty acid of variable length, thirteen to fifteen carbon atoms long. The glutamic acid and aspartic acid residues give the ring its hydrophilic character, as well as its negative charge. Conversely, the valine residue extends down, facing the fatty acid chain, to form a major hydrophobic domain. Below critical micellar concentrations (CMCs), the fatty acid tail can extend freely into solution, participating in hydrophobic interactions within micelles. This antibiotic is synthesized by a linear nonribosomal peptide synthetase, surfactin synthetase (). In solution, it has a characteristic "horse saddle" conformation (PDB: ) that explains its large spectrum of biological activity. | 0 | Colloidal Chemistry |
To calculate the bands including electron-electron interaction many-body effects, one can resort to so-called Greens function methods. Indeed, knowledge of the Greens function of a system provides both ground (the total energy) and also excited state observables of the system. The poles of the Greens function are the quasiparticle energies, the bands of a solid. The Greens function can be calculated by solving the Dyson equation once the self-energy of the system is known. For real systems like solids, the self-energy is a very complex quantity and usually approximations are needed to solve the problem. One such approximation is the GW approximation, so called from the mathematical form the self-energy takes as the product Σ = GW of the Greens function G and the dynamically screened interaction W. This approach is more pertinent when addressing the calculation of band plots (and also quantities beyond, such as the spectral function) and can also be formulated in a completely ab initio' way. The GW approximation seems to provide band gaps of insulators and semiconductors in agreement with experiment, and hence to correct the systematic DFT underestimation. | 1 | Solid-state chemistry |
Ostwald ripening is a process in which large particles grow at the expense of the smaller particles as a result of dissolution of small particles and deposition of the dissolved molecules on the surfaces of the larger particles. It occurs because smaller particles have a higher surface energy than larger particles. This process is typically undesirable in nanoparticle synthesis as it negatively impacts the functionality of nanoparticles. | 0 | Colloidal Chemistry |
Coppens was a corresponding member of the Royal Netherlands Academy of Arts and Sciences since 1979 and a fellow of the American Association for the Advancement of Science from 1993. Additionally, he was awarded the Gregori Aminoff Prize of the Royal Swedish Academy of Sciences in 1996, the Ewald Prize of the International Union of Crystallography in 2005, and Kołos Medal in 2013. | 1 | Solid-state chemistry |
Nanochemistry is an emerging sub-discipline of the chemical and material sciences that deals with the development of new methods for creating nanoscale materials. The term "nanochemistry" was first used by Ozin in 1992 as the uses of chemical synthesis to reproducibly afford nanomaterials from the atom "up", contrary to the nanoengineering and nanophysics approach that operates from the bulk "down". Nanochemistry focuses on solid-state chemistry that emphasizes synthesis of building blocks that are dependent on size, surface, shape, and defect properties, rather than the actual production of matter. Atomic and molecular properties mainly deal with the degrees of freedom of atoms in the periodic table. However, nanochemistry introduced other degrees of freedom that controls material's behaviors by transformation into solutions. Nanoscale objects exhibit novel material properties, largely as a consequence of their finite small size. Several chemical modifications on nanometer-scaled structures approve size dependent effects.
Nanochemistry is used in chemical, materials and physical science as well as engineering, biological, and medical applications. Silica, gold, polydimethylsiloxane, cadmium selenide, iron oxide, and carbon are materials that show its transformative power. Nanochemistry can make the most effective contrast agent of MRI out of iron oxide (rust) which can detect cancers and kill them at their initial stages. Silica (glass) can be used to bend or stop lights in their tracks. Developing countries also use silicone to make circuits for the fluids used in pathogen detection. Nano-construct synthesis leads to the self-assembly of the building blocks into functional structures that may be useful for electronic, photonic, medical, or bioanalytical problems. Nanochemical methods can be used to create carbon nanomaterials such as carbon nanotubes, graphene, and fullerenes which have gained attention in recent years due to their remarkable mechanical and electrical properties. | 0 | Colloidal Chemistry |
Foams can form naturally within a variety of living organisms. For example, wood, cork, and plant matter all can have foam components or structures. Fungi are generally composed of mycelium, which is made up of hollow filaments of chitin nanofibers bound to other components. Animal parts like cancellous bone, horseshoe crab shells, toucan beaks, sponge, coral, feathers, and antlers all contain foam-like structures which decrease overall weight at the expense of other material properties.
Structures like bone, antlers, and shells have strong materials housing weaker but lighter materials within. Bones tend to have compact, dense external regions, which protect the internal foam-like cancelous bone. The same principle applies to horseshoe crab shells, toucan beaks, and antlers. The barbs and shafts of feathers similarly contain closed-cell foam.
Protective foams can be formed externally by parent organisms or by eggs interacting with the environment: tunicate egg mix with sea water to create a liquid-based foam; tree frog eggs grow in protein foams above and on water (see Figure 1); certain freshwater fish lay eggs in surface foam from their mucus; deep sea fish produce eggs in swimbladders of dual layered foams; and some insects keep their larvae in foam. | 0 | Colloidal Chemistry |
Metallic nanofoams have seen a broad variety of applications, including catalysts, hydrogen storage, as well as fuel cells. Additionally, applications of metallic nanofoam as an electrocatalyst have been fruitful; a nickel-iron nanofoam catalyst has proven to exhibit exceptional electrocatalytic performance, as well as water-splitting to isolate hydrogen atoms. Applications to the clean energy industry, specifically for lithium-ion batteries and other fuel cells, have been discussed as well. | 0 | Colloidal Chemistry |
He was awarded by Chemical Society of Japan in 1999 and the Charles Petinos Award by the American Carbon Society in 2007. He is fellow of Chemical Society of Japan since 2011, Royal Society of Chemistry and International Adsorption Society since 2013, and a Senior Member of the AIChE. | 1 | Solid-state chemistry |
Boldyreva was awarded an additional Doctorate in Science in solid-state chemistry in 2000. She was promoted to Professor at the Novosibirsk State University in 2003. Her early work considered photomechanical effects in crystals of coordination complexes. She shifted into high pressure research, working with infrared spectroscopy at the Phillips University in Marburg. Boldyreva has investigated solid pharmaceutical compounds and biomimetic molecules. She also worked at Durham University as a Royal Society Fellow.
She uses high pressure measurements to investigate and control the inter- and intra-molecular interactions in crystals. She has shown you can use pressure to induce new crystalline forms, as well as interrogating chemical reactions. Alongside experimental science, Boldyreva works on Monte Carlo simulations for solid-state reactions.
She serves on the advisory council of the Russian Ministry of Education and Science.
She is an editor for Acta Crystallographica, International Union of Crystallography Research Journal, CrystEngComm Journal of Thermal Analysis and Calorimetry and Pharmalogica. | 1 | Solid-state chemistry |
An acid with higher Acid dissociation constant| value dominates the chemical reaction. It serves as a better contributor of protons (). A comparison between the and Base dissociation constant| indicates the acid–base property of the resulting solution by which:
# The solution is acidic if . It contains a greater concentration of ions than concentration of ions due more extensive of cation hydrolysis compared to that of anion hydrolysis.
# The solution is alkali if . Anions hydrolyze more than cations, causing an exceeding concentration of ions.
# The solution is expected to be neutral only when .
Other possible factors that could vary pH level of a solution are the relevant equilibrium constants and the additional amounts of any base or acid.
For example, in ammonium chloride solution, is the main influence for acidic solution. It has greater value compared to that of water molecules; of is , and of is . This ensures its deprotonation when reacting with water, and is responsible for the pH below 7 at room temperature. will have no affinity for nor tendency to hydrolyze, as its value is very low ( of is ).
Hydrolysis of ammonium at room temperature produces: | 1 | Solid-state chemistry |
A colloidal crystal is a highly ordered array of particles which can be formed over a long range (to about a centimeter). Arrays such as this appear to be analogous to their atomic or molecular counterparts with proper scaling considerations. A good natural example of this phenomenon can be found in precious opal, where brilliant regions of pure spectral color result from close-packed domains of colloidal spheres of amorphous silicon dioxide, SiO (see above illustration). The spherical particles precipitate in highly siliceous pools and form highly ordered arrays after years of sedimentation and compression under hydrostatic and gravitational forces. The periodic arrays of spherical particles make similar arrays of interstitial voids, which act as a natural diffraction grating for light waves in photonic crystals, especially when the interstitial spacing is of the same order of magnitude as the incident lightwave. | 0 | Colloidal Chemistry |
Dielectrophoresis (DEP) is a phenomenon in which a force is exerted on a dielectric particle when it is subjected to a non-uniform electric field. This force does not require the particle to be charged. All particles exhibit dielectrophoretic activity in the presence of electric fields. However, the strength of the force depends strongly on the medium and particles electrical properties, on the particles shape and size, as well as on the frequency of the electric field. Consequently, fields of a particular frequency can manipulate particles with great selectivity. This has allowed, for example, the separation of cells or the orientation and manipulation of nanoparticles and nanowires. Furthermore, a study of the change in DEP force as a function of frequency can allow the electrical (or electrophysiological in the case of cells) properties of the particle to be elucidated. | 0 | Colloidal Chemistry |
Cooled to very low temperatures, some materials experience a sudden transition where electrical resistance drops to zero and any magnetic fields are expelled. This phenomenon is called superconductivity. Superconductors have a host of applications including powerful electromagnets, fast digital circuits and sensitive magnetometers, but the very low temperatures needed make the applications more difficult and expensive. Until the 1980s, no superconductors existed above . Then in 1986 two IBM researchers, Georg Bednorz and K. Alex Müller, found a ceramic material with a critical temperature of . This set off a frenzied search for higher critical temperatures.
A group led by Paul Chu at the University of Houston explored some materials made of yttrium, barium, copper and oxygen (YCBO) and were the first to obtain a critical temperature above the boiling point of liquid nitrogen. The YCBO samples had a mixture of black and green minerals, and although the researchers knew the average composition, they did not know the compositions of the two phases. In February 1987, Chu turned to Mao and Hazen, because they could determine the composition of small mineral grains in rocks. It took Mao and Hazen a week to determine the compositions; the black phase, which turned out to be the superconductor, was YBaCuO.
Mao and Hazen determined that the crystal structure of the superconducting phase was like that of perovskite, an important mineral in Earths mantle. Subsequently, Hazens group identified twelve more high-temperature oxide superconductors, all with perovskite structures, and worked on organic superconductors. | 1 | Solid-state chemistry |
Nanoparticle drug delivery systems are engineered technologies that use nanoparticles for the targeted delivery and controlled release of therapeutic agents. The modern form of a drug delivery system should minimize side-effects and reduce both dosage and dosage frequency. Recently, nanoparticles have aroused attention due to their potential application for effective drug delivery.
Nanomaterials exhibit different chemical and physical properties or biological effects compared to larger-scale counterparts that can be beneficial for drug delivery systems. Some important advantages of nanoparticles are their high surface-area-to-volume ratio, chemical and geometric tunability, and their ability to interact with biomolecules to facilitate uptake across the cell membrane. The large surface area also has a large affinity for drugs and small molecules, like ligands or antibodies, for targeting and controlled release purposes.
Nanoparticles refer to a large family of materials both organic and inorganic. Each material has uniquely tunable properties and thus can be selectively designed for specific applications. Despite the many advantages of nanoparticles, there are also many challenges, including but not exclusive to: nanotoxicity, biodistribution and accumulation, and the clearance of nanoparticles by human body.
The National Institute of Biomedical Imaging and Bioengineering has issued the following prospects for future research in nanoparticle drug delivery systems:
# crossing the blood-brain barrier (BBB) in brain diseases and disorders;
# enhancing targeted intracellular delivery to ensure the treatments reach the correct structures inside cells;
# combining diagnosis and treatment.
The development of new drug systems is time-consuming; it takes approximately seven years to complete fundamental research and development before advancing to preclinical animal studies. | 0 | Colloidal Chemistry |
Wöhler's 1823 synthesis involved reducing sodium tungstate and tungsten trioxide with hydrogen gas at red heat. A more modern approach reduces a melt of the reactants with electricity rather than with hydrogen. Microwave synthesis is also possible, using tungsten powder as the reducing agent. Hydrothermal (both batch and flow) syntheses are also possible. | 1 | Solid-state chemistry |
Hydrogen passivation is one way to saturate these dangling bonds. This passivation process is carried out by one of the following mechanisms: deposition of a thin film from silicon nitride SiNx on the top of the polycrystalline silicon layer, or passivation by remote plasma hydrogen passivation (RPHP). In the latter method, hydrogen, oxygen, and argon gases react inside the chamber, then, the hydrogen is dissociating to the atomic hydrogen under the plasma condition to diffuse into the silicon interface to saturate the dangling bonds. This saturation reduces the interface defect state, where the recombination takes place. | 1 | Solid-state chemistry |
Elena Vladimirovna Boldyreva (born 4 February 1961) is a Russian chemist. Boldyreva is a leading researcher at the Boreskov Institute of Catalysis in the Siberian Branch of Russian Academy of Sciences, and is Professor and Head of the Section of Solid State Chemistry at Novosibirsk State University. | 1 | Solid-state chemistry |
ELS has been used to characterize the polydispersity, nanodispersity, and stability of single-walled carbon nanotubes in an aqueous environment with surfactants. The technique can be used in combination with dynamic light scattering to measure these properties of nanotubes in many different solvents. | 0 | Colloidal Chemistry |
Sodium tungsten bronze is a form of insertion compound with the formula NaWO, where x is equal to or less than 1. So named because of its metallic lustre, its electrical properties range from semiconducting to metallic depending on the concentration of sodium ions present; it can also exhibit superconductivity. | 1 | Solid-state chemistry |
According to the International Standards Organization (ISO) technical specification 80004, a nanoparticle is an object with all three external dimensions in the nanoscale, whose longest and shortest axes do not differ significantly, with a significant difference typically being a factor of at least 3. | 0 | Colloidal Chemistry |
Being smaller than the wavelengths of visible light, nanoparticles can be dispersed in transparent media without affecting its transparency at those wavelengths. This property is exploited in many applications, such as photocatalysis. | 0 | Colloidal Chemistry |
Inert-gas condensation is frequently used to produce metallic nanoparticles. The metal is evaporated in a vacuum chamber containing a reduced atmosphere of an inert gas. Condensation of the supersaturated metal vapor results in creation of nanometer-size particles, which can be entrained in the inert gas stream and deposited on a substrate or studied in situ. Early studies were based on thermal evaporation. Using magnetron sputtering to create the metal vapor allows to achieve higher yields. The method can easily be generalized to alloy nanoparticles by choosing appropriate metallic targets. The use of sequential growth schemes, where the particles travel through a second metallic vapor, results in growth of core-shell (CS) structures. | 0 | Colloidal Chemistry |
Emerging methods of drug delivery involving nanotechnological methods can be useful by improving bodily response, specific targeting, and non-toxic metabolism. Many nanotechnological methods and materials can be functionalized for drug delivery. Ideal materials employ a controlled-activation nanomaterial to carry a drug cargo into the body. Mesoporous silica nanoparticles (MSN) have increased in research popularity due to their large surface area and flexibility for various individual modifications while maintaining high-resolution performance under imaging techniques. Activation methods greatly vary across nanoscale drug delivery molecules, but the most commonly used activation method uses specific wavelengths of light to release the cargo. Nanovalve-controlled cargo release uses low-intensity light and plasmonic heating to release the cargo in a variation of MSN containing gold molecules. The two-photon activated photo-transducer (2-NPT) uses near infrared wavelengths of light to induce the breaking of a disulfide bond to release the cargo. Recently, nanodiamonds have demonstrated potential in drug delivery due to non-toxicity, spontaneous absorption through the skin, and the ability to enter the blood–brain barrier.
The unique structure of carbon nanotubes also gives rise to many innovative inventions of new medical methods. As more medicine is made at the nano level to revolutionize the ways for human to detect and treat diseases, carbon nanotubes become a stronger candidate in new detection methods and therapeutic strategies. Specially, carbon nanotubes can be transformed into sophisticated biomolecule and allow its detection through changes in the carbon nanotube fluorescence spectra. Also, carbon nanotubes can be designed to match the size of small drug and endocitozed by a target cell, hence becoming a delivery agent. | 0 | Colloidal Chemistry |
Copper(II) oxide dissolves in mineral acids such as hydrochloric acid, sulfuric acid or nitric acid to give the corresponding copper(II) salts:
: CuO + 2 HNO → Cu(NO) + HO
: CuO + 2 HCl → CuCl + HO
: CuO + HSO → CuSO + HO
In presense of water It reacts with concentrated alkali to form the corresponding cuprate salts:
: 2 MOH + CuO + HO → M[Cu(OH)]
: 2 NaOH + CuO + HO → Na[Cu(OH)]
It can also be reduced to copper metal using hydrogen, carbon monoxide, or carbon:
: CuO + H → Cu + HO
: CuO + CO → Cu + CO
: 2 CuO + C → 2Cu + CO
When cupric oxide is substituted for iron oxide in thermite the resulting mixture is a low explosive, not an incendiary. | 1 | Solid-state chemistry |
The 11 September 2001 collapse of the World Trade Center buildings in New York City resulted in the release of chemicals from the destruction of construction and electrical material and long-term chemical fires. This collapse caused the release of several toxic chemicals, including fluorinated surfactants used as soil- and stain-resistant coatings on various materials. First responders to this incident were exposed to PFOA, PFNA, and PFHxS through inhalation of dust and smoke released during and after the collapse of the World Trade Center.
Fire responders who were working at or near ground zero were assessed for respiratory and other health effects from exposure to emissions at the World Trade Center. Early clinical testing showed a high prevalence of respiratory health effects. Early symptoms of exposure often presented with persistent coughing and wheezing. PFOA and PFHxS levels were present in both smoke and dust exposure, but first responders exposed to smoke had higher concentrations of PFOA and PFHxS than those exposed to dust. | 0 | Colloidal Chemistry |
In general, the Gibbs free energy of micellization can be approximated as:
where is the change in Gibbs free energy of micellization, is the universal gas constant, is the absolute temperature, and is the critical micelle concentration. | 0 | Colloidal Chemistry |
Europium hydride is the most common hydride of europium with a chemical formula EuH. In this compound, europium atom is in the +2 oxidation state and the hydrogen atoms are -1. It is a ferromagnetic semiconductor. | 1 | Solid-state chemistry |
Cerebos is a brand of salt and, more recently, of other flavourings and nutritional supplements. Ownership of Cerebos brand is divided between Kraft Heinz in Asia Pacific, Australia and New Zealand, Premier Foods in UK, K+S in Western Europe, and Bud Group in South Africa. The product was developed by George Weddell, a Scottish chemist working at the British company Mawson & Swan, and sold under the Cerebos brand by a new partnership, Mawson, Swan & Weddell.
The company Cerebos Ltd was later registered in 1894. At the time of its introduction, salt was sold in large blocks from which the user would scrape what they needed. Free-running salt was a novelty because, left for any length of time, pure sodium chloride crystals would absorb sufficient moisture from the air to cause them to stick together, a phenomenon called caking. Its slogan was "See How It Runs", because the salt contained anti-caking agents. The slogan was echoed in the product branding of a small boy chasing a chicken, a reference to the superstition that birds might be caught by pouring salt onto their tail.
Ernest Shackleton lists Cerebos salt among the few precious stocks taken in the James Caird on his trip with five men from Elephant Island to South Georgia as he attempted to engineer a daring escape from the Antarctic.
From 1923 until the mid 1900s, Cerebos Ltd had a factory at the then 10 Victoria Road, in North Acton, northwest London, UK. The company was purchased by Rank Hovis McDougall (RHM) in 1968, and the site was redeveloped into the Shaftesbury Gardens housing development in the mid 1990's.
Cerebos salt is sold in Western Europe (including France where it is spelt Cérébos), Australia, New Zealand and South Africa. The Australian and New Zealand operations were part of Cerebos Pacific, and now owned by Kraft Heinz which acquired most of its assets from Suntory Holdings in 2018, and includes the well known local brands:
*Greggs (NZ)
*Robert Harris (NZ)
*Bisto (NZ)
*[http://www.cerebosfoodservice.co.nz/food/powdered-beverages/ Raro] (NZ)
*atomic (NZ)
*Whitlock's (NZ)
*L'affare (NZ)
*Bruno Rossi (NZ)
*Gravox (Australia)
*Fountain (Australia)
*Toby Estate (Australia)
*Saxa (Australia)
*Foster Clark's (Australia)
*Mocopan (Australia)
*Asian Home Gourmet (Australia) | 1 | Solid-state chemistry |
Hui Wu () is a Chinese materials chemist and engineer. She is a senior scientist at the National Institute of Standards and Technology Center for Neutron Research. Wu researches the synthesis, structure, solid state chemistry, and properties of complex oxides and hydrides. She received the Department of Commerce Bronze Medal for producing an entirely new route to synthesizing hydrogen-storage materials for fuel cells based on the complex chemistry of amines and boranes. | 1 | Solid-state chemistry |
A detergent similar to soap was manufactured in ancient China from the seeds of Gleditsia sinensis. Another traditional detergent is a mixture of pig pancreas and plant ash called zhuyizi (). Soap made of animal fat did not appear in China until the modern era. Soap-like detergents were not as popular as ointments and creams. | 1 | Solid-state chemistry |
The method of production influences the polymorph generated. For example, thin films of pure γ-InSe have been produced from trimethylindium (InMe) and hydrogen selenide via MOCVD techniques.
A conventional route entails heating the elements in a seal-tube: | 1 | Solid-state chemistry |
Potash (especially potassium carbonate) has been used in bleaching textiles, making glass, ceramic, and making soap, since the Bronze Age. Potash was principally obtained by leaching the ashes of land plants. | 1 | Solid-state chemistry |
Multilayer molybdenite flakes are semiconductors with an indirect bandgap. In contrast, monolayer flakes have a direct gap. In the early years of the 20th century, molybdenite was used in some of the first crude semiconductor diodes, called cat's whisker detectors, which served as a demodulator in early crystal radios. Monolayer molybdenite shows good charge carrier mobility and can be used to create small or low-voltage transistors. The transistors can detect and emit light and may have future use in optoelectronics. | 1 | Solid-state chemistry |
Estropipate has been discontinued in the United States. In the past, estropipate has also been marketed in Canada, the United Kingdom, Ireland, Switzerland, Australia, South Africa, Mexico, and Indonesia. | 1 | Solid-state chemistry |
In lipid polymorphism, if the packing ratio of lipids is greater or less than one, lipid membranes can form two separate hexagonal phases, or nonlamellar phases, in which long, tubular aggregates form according to the environment in which the lipid is introduced. | 0 | Colloidal Chemistry |
Natural swelling: in this method soluble lipids in chloroform are pipetted on a Teflon ring. The chloroform is allowed to evaporate and the ring is then placed under the vacuum for several hours. Next the aqueous buffer is added gently over the Teflon ring and lipids are allowed to naturally swell to form GUVs overnight. the disadvantage of this method is that a large amount of multilamellar vesicles and lipid debris are formed.
Electroformation: In this method lipids are placed on a conductive cover glass (indium tin oxide or ITO coated glass) or on Pt wires instead of a Teflon ring and after vacuuming, buffer is placed on the dried lipids and it is sandwiched using a second conductive cover glass. Next an electrical field with certain frequency and voltage is applied which promotes formation of GUVs. For polyunsaturated lipids, this technique can induce a significant oxidation effect on the vesicles. Nevertheless, it is a very common and reliable technique to generate GUVs. Modified approaches exist that employ gel-assisted swelling (agarose-assisted swelling or PVA-assisted swelling) for the formation of GUVs under more biologically relevant conditions.
A variety of methods exist to encapsulate biological reactants within GUVs by using water-oil interfaces as a scaffold to assemble lipid layers. This allows the use GUVs as cell-like membrane containers for the in vitro recreation (and investigation) of biological functions. These encapsulation methods include microfluidic methods, which allow for a high-yield production of vesicles with consistent sizes. | 0 | Colloidal Chemistry |
In chemistry, a salt or ionic compound is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a neutral compound with no net electric charge. The constituent ions are held together by electrostatic forces termed ionic bonds.
The component ions in a salt can be either inorganic, such as chloride (Cl), or organic, such as acetate (). Each ion can be either monatomic (termed simple ion), such as fluoride (F), and sodium (Na) and chloride (Cl) in sodium chloride, or polyatomic, such as sulfate (), and ammonium () and carbonate () ions in ammonium carbonate. Salt containing basic ions hydroxide (OH) or oxide (O) are classified as bases, for example sodium hydroxide.
Individual ions within a salt usually have multiple near
neighbours, so are not considered to be part of molecules, but instead part of a continuous three-dimensional network. Salts usually form crystalline structures when solid.
Salts composed of small ions typically have high melting and boiling points, and are hard and brittle. As solids they are almost always electrically insulating, but when melted or dissolved they become highly conductive, because the ions become mobile. Some salts have large cations, large anions, or both. In terms of their properties, such species often are more similar to organic compounds. | 1 | Solid-state chemistry |
In the Atacama Desert in northern Chile, vast deposits of a mixture, also referred to as caliche, are composed of gypsum, sodium chloride and other salts, and sand, associated to salitre ("Chile saltpeter"). Salitre, in turn, is a composite of sodium nitrate (NaNO) and potassium nitrate (KNO). Salitre was an important source of export revenue for Chile until World War I, when Europe began to produce both nitrates industrially in large quantities.
The deposits contain an average of 7.5% sodium nitrate, as well as sodium sulfate (18.87%), sodium chloride (4.8%), and smaller amounts of potassium, calcium, magnesium, borate, iodine, and perchlorate. About two-thirds of the deposits are insoluble gangue minerals. The caliche beds are from 2 cm to several meters thick in alluvial deposits, where the soluble minerals form a cement in unconsolidated regolith. Nitrate-bearing caliche is also found impregnating bedrock to form bedrock deposits. | 1 | Solid-state chemistry |
Magnetite has been found as nano-crystals in magnetotactic bacteria (42–45 nm) and in the beak tissue of homing pigeons. | 1 | Solid-state chemistry |
Miriam M. Unterlass studied chemistry, process engineering and materials science in Würzburg, Southampton, and Lyon. She then completed her PhD with the thesis "From monomer salts and their tectonic crystals to aromatic polyimides: development of neoteric synthesis routes" at the Max Planck Institute of Colloids and Interfaces and did a postdoc at the École supérieure de physique et de chimie industrielles de la ville de Paris. In 2013, she started as an independent group leader at the Vienna University of Technology and habilitated there in materials chemistry in 2018, becoming an assistant professor there with tenure in 2019. Since 2018, she has been a member of the Young Academy of the Austrian Academy of Sciences. In 2021, she became a full professor of solid state chemistry at the University of Konstanz. She has received several prizes and awards during this time, including the PHÖNIX Prize in the "Prototypes" category and being named a "Young Talent 2016" by the journal Marcomolecular Chemistry and Physics. In 2023, she received the Roy Somiya Award 2023 from the International Solvothermal and Hydrothermal Association (ISHA) for her contributions to solvothermal and hydrothermal research. | 1 | Solid-state chemistry |
Saline (also known as saline solution) is a mixture of sodium chloride (salt) and water. It has a number of uses in medicine including cleaning wounds, removal and storage of contact lenses, and help with dry eyes. By injection into a vein, it is used to treat dehydration such as that from gastroenteritis and diabetic ketoacidosis. Large amounts may result in fluid overload, swelling, acidosis, and high blood sodium. In those with long-standing low blood sodium, excessive use may result in osmotic demyelination syndrome.
Saline is in the crystalloid family of medications. It is most commonly used as a sterile 9 g of salt per litre (0.9%) solution, known as normal saline. Higher and lower concentrations may also occasionally be used. Saline is acidic, with a pH of 5.5 (due mainly to dissolved carbon dioxide).
The medical use of saline began around 1831. It is on the World Health Organization's List of Essential Medicines. In 2020, sodium was the 274th most commonly prescribed medication in the United States, with more than 1million prescriptions. | 1 | Solid-state chemistry |
Automotive engine oils contain both detergents and dispersants. Metallic-based detergents prevent the accumulation of varnish like deposits on the cylinder walls. They also neutralize acids. Dispersants maintain contaminants in suspension.
Dispersants added to gasoline prevent the buildup of gummy residues. | 0 | Colloidal Chemistry |
Many metal foam manufacturing techniques are accomplished by the introduction of a gaseous phase into a precursor matrix, which can occur in either molten metal or a powdered metal form. Due to titanium's high melting point (1670 °C) and high chemical affinity with oxygen, nitrogen, carbon and hydrogen (which dissolve rapidly either in liquid or solid titanium at a temperature above 400 °C), solid-state processes based on powder densification are the preferred method of fabrication.
Processing methods must also be designed to avoid exposure to air or moisture; vacuum or inert gas sintering processes are usually sufficient for preventing contamination. | 0 | Colloidal Chemistry |
The amount of suitable PAC isotopes required for a measurement is between about 10 to 1000 billion atoms (10-10). The right amount depends on the particular properties of the isotope. 10 billion atoms are a very small amount of substance. For comparison, one mol contains about 6.22x10 particles. 10 atoms in one cubic centimeter of beryllium give a concentration of about 8 nmol/L (nanomol=10 mol). The radioactive samples each have an activity of 0.1-5 MBq, which is in the order of the exemption limit for the respective isotope.
How the PAC isotopes are brought into the sample to be examined is up to the experimenter and the technical possibilities. The following methods are usual: | 1 | Solid-state chemistry |
NaH is a base of wide scope and utility in organic chemistry. As a superbase, it is capable of deprotonating a range of even weak Brønsted acids to give the corresponding sodium derivatives. Typical "easy" substrates contain O-H, N-H, S-H bonds, including alcohols, phenols, pyrazoles, and thiols.
NaH notably deprotonates carbon acids (i.e., C-H bonds) such as 1,3-dicarbonyls such as malonic esters. The resulting sodium derivatives can be alkylated. NaH is widely used to promote condensation reactions of carbonyl compounds via the Dieckmann condensation, Stobbe condensation, Darzens condensation, and Claisen condensation. Other carbon acids susceptible to deprotonation by NaH include sulfonium salts and DMSO. NaH is used to make sulfur ylides, which in turn are used to convert ketones into epoxides, as in the Johnson–Corey–Chaykovsky reaction. | 1 | Solid-state chemistry |
Teri W. Odom is an American chemist and materials scientist. She is the chair of the chemistry department, the Joan Husting Madden and William H. Madden, Jr. Professor of Chemistry, and a professor of materials science and engineering at Northwestern University. She is affiliated with the university's International Institute for Nanotechnology, Chemistry of Life Processes Institute, Northwestern Initiative for Manufacturing Science and Innovation, Interdisciplinary Biological Sciences Graduate Program, and department of applied physics. | 1 | Solid-state chemistry |
Calcium hexaboride is irritating to the eyes, skin, and respiratory system. This product should be handled with proper protective eyeware and clothing. Never put calcium hexaboride down the drain or add water to it. | 1 | Solid-state chemistry |
SnO is used in sensors of combustible gases including carbon monoxide detectors. In these the sensor area is heated to a constant temperature (few hundred °C) and in the presence of a combustible gas the electrical resistivity drops.
Room temperature gas sensors are also being developed using reduced graphene oxide-SnO composites(e.g. for ethanol detection).
Doping with various compounds has been investigated (e.g. with CuO). Doping with cobalt and manganese, gives a material that can be used in e.g. high voltage varistors. Tin(IV) oxide can be doped with the oxides of iron or manganese. | 1 | Solid-state chemistry |
In its 2012 proposed terminology for biologically related polymers, the IUPAC defined a nanoparticle as "a particle of any shape with dimensions in the 1 × 10 and 1 × 10 m range". This definition evolved from one given by IUPAC in 1997.
In another 2012 publication, the IUPAC extends the term to include tubes and fibers with only two dimensions below 100 nm. | 0 | Colloidal Chemistry |
Seeded supersonic nozzle Seeded supersonic nozzles are mostly used to create clusters of low-boiling-point metal. In this source method metal is vaporized in a hot oven. The metal vapor is mixed with (seeded in) inert carrier gas. The vapor mixture is ejected into a vacuum chamber via a small hole, producing a supersonic molecular beam. The expansion into vacuum proceeds adiabatically cooling the vapor. The cooled metal vapor becomes supersaturated, condensing in cluster form.
Gas aggregation Gas aggregation is mostly used to synthesize large clusters of nanoparticles. Metal is vaporized and introduced in a flow of cold inert gas, which causes the vapor to become highly supersaturated. Due to the low temperature of the inert gas, cluster production proceeds primarily by successive single-atom addition.
Laser vaporization Laser vaporization source can be used to create clusters of various size and polarity. Pulse laser is used to vaporize the target metal rod and the rod is moved in a spiral so that a fresh area can be evaporated every time. The evaporated metal vapor is cooled by using cold helium gas, which causes the cluster formation.
Pulsed arc cluster ion This is similar to laser vaporization, but an intense electric discharge is used to evaporate the target metal.
Ion sputtering Ion sputtering source produces an intense continuous beam of small singly ionized cluster of metals. Cluster ion beams are produced by bombarding the surface with high energetic inert gas (krypton and xenon) ions. The cluster production process is still not fully understood.
Liquid-metal ion In liquid-metal ion source a needle is wetted with the metal to be investigated. The metal is heated above the melting point and a potential difference is applied. A very high electric field at the tip of the needle causes a spray of small droplets to be emitted from the tip. Initially very hot and often multiply ionized droplets undergo evaporative cooling and fission to smaller clusters. | 0 | Colloidal Chemistry |
MgB is a multi-band superconductor, that is each Fermi surface has different superconducting energy gap. For MgB, sigma bond of boron is strong, and it induces large s-wave superconducting gap, and pi bond is weak and induces small s-wave gap.
The quasiparticle states of the vortices of large gap are highly confined to the vortex core.
On the other hand, the quasiparticle states of small gap are loosely bound to the vortex core. Thus they can be delocalized and overlap easily between adjacent vortices. Such delocalization can strongly contribute to the thermal conductivity, which shows abrupt increase above H. | 1 | Solid-state chemistry |
Several conditions are needed to produce foam: there must be mechanical work, surface active components (surfactants) that reduce the surface tension, and the formation of foam faster than its breakdown.
To create foam, work (W) is needed to increase the surface area (ΔA):
where γ is the surface tension.
One of the ways foam is created is through dispersion, where a large amount of gas is mixed with a liquid. A more specific method of dispersion involves injecting a gas through a hole in a solid into a liquid. If this process is completed very slowly, then one bubble can be emitted from the orifice at a time as shown in the picture below.
One of the theories for determining the separation time is shown below; however, while this theory produces theoretical data that matches the experimental data, detachment due to capillarity is accepted as a better explanation.
The buoyancy force acts to raise the bubble, which is
where is the volume of the bubble, is the acceleration due to gravity, and ρ is the density of the gas ρ is the density of the liquid. The force working against the buoyancy force is the surface tension force, which is
where γ is the surface tension, and is the radius of the orifice.
As more air is pushed into the bubble, the buoyancy force grows quicker than the surface tension force. Thus, detachment occurs when the buoyancy force is large enough to overcome the surface tension force.
In addition, if the bubble is treated as a sphere with a radius of and the volume is substituted in to the equation above, separation occurs at the moment when
Examining this phenomenon from a capillarity viewpoint for a bubble that is being formed very slowly, it can be assumed that the pressure inside is constant everywhere. The hydrostatic pressure in the liquid is designated by . The change in pressure across the interface from gas to liquid is equal to the capillary pressure; hence,
where R and R are the radii of curvature and are set as positive. At the stem of the bubble, R and R are the radii of curvature also treated as positive. Here the hydrostatic pressure in the liquid has to take in account z, the distance from the top to the stem of the bubble. The new hydrostatic pressure at the stem of the bubble is p(ρ − ρ)z. The hydrostatic pressure balances the capillary pressure, which is shown below:
Finally, the difference in the top and bottom pressure equal the change in hydrostatic pressure:
At the stem of the bubble, the shape of the bubble is nearly cylindrical; consequently, either R or R is large while the other radius of curvature is small. As the stem of the bubble grows in length, it becomes more unstable as one of the radius grows and the other shrinks. At a certain point, the vertical length of the stem exceeds the circumference of the stem and due to the buoyancy forces the bubble separates and the process repeats. | 0 | Colloidal Chemistry |
Published analytical test methods for turbidity include:
* ISO 7027 "Water Quality: Determination of Turbidity"
* US EPA Method No. 180.1, "Turbidity"
* "Standard Methods", No. 2130B. | 0 | Colloidal Chemistry |
The sponge bomb was developed by the Israel Defense Forces (IDF) to address the use of tunnels by Hamas in Gaza. | 0 | Colloidal Chemistry |
The widely used herbicide paraquat is a viologen. This application is the largest consumer of this class of compounds. The toxicity of the 2,2-, 4,4-, or 2,4'-bipyridylium-based viologens is related to their ability to form stable free radicals. This redox activity allows these species to interfere with the electron transport chain in the plant.
Viologens have been commercialized as electrochromic systems because of their highly reversible and dramatic change of color upon reduction and oxidation. In some applications, N-heptyl viologens are used. Conducting solid supports such as titania and indium tin oxide have been used. | 1 | Solid-state chemistry |
A hydrogel is a biphasic material, a mixture of porous, permeable solids and at least 10% by weight or volume of interstitial fluid composed completely or mainly by water. In hydrogels the porous permeable solid is a water insoluble three dimensional network of natural or synthetic polymers and a fluid, having absorbed a large amount of water or biological fluids. These properties underpin several applications, especially in the biomedical area. Many hydrogels are synthetic, but some are derived from nature. The term hydrogel was coined in 1894. | 0 | Colloidal Chemistry |
Metal halides are used in high-intensity discharge lamps called metal halide lamps, such as those used in modern street lights. These are more energy-efficient than mercury-vapor lamps, and have much better colour rendition than orange high-pressure sodium lamps. Metal halide lamps are also commonly used in greenhouses or in rainy climates to supplement natural sunlight.
Silver halides are used in photographic films and papers. When the film is developed, the silver halides which have been exposed to light are reduced to metallic silver, forming an image.
Halides are also used in solder paste, commonly as a Cl or Br equivalent.
Synthetic organic chemistry often incorporates halogens into organohalide compounds. | 1 | Solid-state chemistry |
Rao is one of the world's foremost solid state and materials chemists. He has contributed to the development of the field over five decades. His work on transition metal oxides has led to basic understanding of novel phenomena and the relationship between materials properties and the structural chemistry of these materials.
Rao was one of the earliest to synthesise two-dimensional oxide materials such as LaCuO. He was one of the first to synthesise 123 cuprates, the first liquid nitrogen-temperature superconductor in 1987. He was also the first to synthesis Y junction carbon nanotubes in the mid-1990s. His work has led to a systematic study of compositionally controlled metal-insulator transitions. Such studies have had a profound impact in application fields such as colossal magneto resistance and high temperature superconductivity. Oxide semiconductors have unusual promise. He has made immense contributions to nanomaterials over the last two decades, besides his work on hybrid materials.
He shares co-authorship of more than 1750 research papers and has co-authored or edited more than 54 books. | 1 | Solid-state chemistry |
Lauryldimethylamine oxide (LDAO), also known as dodecyldimethylamine oxide (DDAO), is an amine oxide–based zwitterionic surfactant, with a C (dodecyl) alkyl tail. It is one of the most frequently-used surfactants of this type. Like other amine oxide–based surfactants it is antimicrobial, being effective against common bacteria such as S. aureus and E. coli, however, it is also non-denaturing and may be used to solubilize proteins.
At high concentrations, LDAO forms liquid crystalline phases. Despite having only one polar atom that is able to interact with water – the oxygen atom (the quaternary nitrogen atom is hidden from intermolecular interactions), DDAO is a strongly amphiphilic surfactant: it forms normal micelles and normal liquid crystalline phases. High amphiphilicity of this surfactant can be explained by the fact that it forms not only very strong hydrogen bonds with water: the energy of DDAO – water hydrogen bond is about 50 kJ/mol, but it also has high experimental partition coefficient in non-polar medium, as characterized by experimental logP 5.284 | 0 | Colloidal Chemistry |
Localized surface plasmons are distinct from propagating surface plasmons. In localized surface plasmons, the electron cloud oscillates collectively. In propagating surface plasmons, the surface plasmon propagates back and forth between the ends of the structure. Propagating surface plasmons also need to have at least one dimension that is close to or longer than the wavelength of incident light. The waves created in propagating surface plasmons can also be tuned by controlling the geometry of the metal nanostructure. | 0 | Colloidal Chemistry |
Percobaltates are chemical compounds where the oxidation state of cobalt is +5. This is the highest established oxidation state of cobalt. The simplest of these are bi-metallic Group 1 oxides such as sodium percobaltate (NaCoO); which may be produced by the reaction of cobalt(II,III) oxide and sodium oxide, using oxygen as the oxidant:
: 4 CoO + 18 NaO + 7 O → 12 NaCoO
The potassium salt can be synthesized similarly; its magnetic moment has indicated the existence of cobalt(V). No crystallographic analysis has been reported for either material. Percobaltates can be stabilized by use of oxides or fluorides.
A number of organometallic Co(V) complexes have also been reported. | 1 | Solid-state chemistry |
As the Clarence B. Robinson Professor at George Mason University, Hazen developed innovative courses to promote scientific literacy in both scientists and non-scientists. With physicist James Trefil, he developed a course that they described as "science appreciation", aimed at non-scientists. It was organized around a total of 20 "Great Ideas of Science" that were later reduced to 18. In addition to writing about their ideas in several magazines, they turned the course into a book, Science Matters: Achieving Scientific Literacy. They used the principles to organize explanations of a "vast number of socially significant, fundamental, or environmentally crucial topics." This was published with an amount of advance publicity that was unusual for a popular science book, including an article they wrote for the New York Times Sunday Magazine, praise from prolific author Isaac Asimov and physics Nobelist Leon Lederman, and a publicity tour. For an article in Science about the book, they provided the author with the original list of 20 ideas and invited readers to send in their comments. About 200 readers responded, generally supporting the idea of such a list while vehemently criticizing many of the particulars, including an informal style and sometimes vague language. Particularly criticized were numbers 1 ("The universe is regular and predictable") and 16 ("Everything on the earth operates in cycles"). Hazen and Trefil argued, in defense of point 1, that it was not intended as a defense of determinism and that they covered unpredictable phenomena like chaos; but they also used the responses to modify the list of ideas in subsequent editions.
Hazen and Trefil went on to write three undergraduate textbooks: The Sciences: An Integrated Approach (1993), The Physical Sciences: An Integrated Approach (1995), and Physics Matters: An Introduction to Conceptual Physics (2004). Hazen used these as the basis for a 60-lecture video and audio course called The Joy of Science. | 1 | Solid-state chemistry |
Mycosubtilin is a natural lipopeptide with antifungal and hemolytic activities and isolated from Bacillus species. It belongs to the iturin lipopeptide family. | 0 | Colloidal Chemistry |
*Alfred P. Sloan Fellow (1973)
*Mineralogical Society of America Award and Fellow (1981)
*American Geophysical Union Fellow (1988)
*Member, National Academy of Sciences (1993)
*President, Mineralogical Society of America (1992–1993)
*Honorary doctorate from the Faculty of Science and Technology at Uppsala University, Sweden (1995)
*Ross Coffin Purdy Award, American Ceramic Society Fellow (1995)
*Geochemical Society Fellow (1997)
*Alexander M. Cruickshank Award, Gordon Research Conference (2000)
*Hugh Huffman Memorial Award, The Calorimetry Conference (2000)
*Ceramic Educational Council Outstanding Educator Award (2000)
*American Ceramic Society Fellow (2001)
*American Ceramic Society, Best Paper Award of the Nuclear and Environmental Technology Division (2001)
*Benjamin Franklin Medal in Earth Science (2002)
*Highly Cited Researchers Award, ISI Thomson Scientific (2002)
*Fellow, The Mineralogical Society (Great Britain) (2004)
*Urey Medal, European Association of Geochemistry (EAG) (2005)
*Spriggs Phase Equilibria Award, American Ceramic Society (ACerS)(2005)
*Rossini Award, International Association of Chemical Thermodynamics (IACT)(2006)
*Harry H. Hess Medal, American Geophysical Union (AGU)(2006)
*Roebling Medal, Mineralogical Society of America (2009) | 1 | Solid-state chemistry |
His research focuses on the following topics:
* solid-state chemistry
* quantum chemistry
* nitrides
* carbodiimides
* guanidinates
* intermetallics
* steel
* phase-change materials
* chemical bonding (e.g., Crystal Orbital Hamilton Populations)
* ab initio thermochemistry
* structural chemistry
* neutron diffraction | 1 | Solid-state chemistry |
The most popular biofoam in the use of biomedical devices is PLA as well. PLA's properties are also desirable in biomedical applications, especially in combination with other polymers. Specifically, its biocompatibility and biodegradability make it favorable in tissue engineering through the use of FDM-3D printing. PLA does well in these printing environments as its glass transition temperature as well as shape memory is small. In recent studies, PLA has been specifically combined with hydroxyapatite (HA) in order to make the modulus of the sample more favorable for its application in repairing bone failure. Specifically in tissue engineering, HA has also been shown to generate osteogenesis by triggering osteoblasts and pre-osteoblastic cells. HA is a strong material, which makes it ideal to add to PLA, due to the fact that PLA has weak toughness with a 10% elongation before failure. FFF-based 3D printing was used as well as compression tests demonstrated in Figure 5. The results showed that there was a self-healing capability of the sample, which could be used in certain biomedical practices. | 0 | Colloidal Chemistry |
Graphitic carbon nitride (g-CN) is a family of carbon nitride compounds with a general formula near to CN (albeit typically with non-zero amounts of hydrogen) and two major substructures based on heptazine and poly(triazine imide) units which, depending on reaction conditions, exhibit different degrees of condensation, properties and reactivities. | 1 | Solid-state chemistry |
In solid-state physics, the Poole–Frenkel effect (also known as Frenkel-Poole emission) is a model describing the mechanism of trap-assisted electron transport in an electrical insulator. It is named after Yakov Frenkel, who published on it in 1938, extending the theory previously developed by H. H. Poole.
Electrons can move slowly through an insulator by the following process. The electrons are generally trapped in localized states (loosely speaking, they are "stuck" to a single atom, and not free to move around the crystal). Occasionally, random thermal fluctuations will give an electron enough energy to leave its localized state, and move to the conduction band. Once there, the electron can move through the crystal, for a brief amount of time, before relaxing into another localized state (in other words, "sticking" to a different atom). The Poole–Frenkel effect describes how, in a large electric field, the electron doesn't need as much thermal energy to be promoted into the conduction band (because part of this energy comes from being pulled by the electric field), so it does not need as large a thermal fluctuation and will be able to move more frequently.
On theoretical grounds, the Poole–Frenkel effect is comparable to the Schottky effect, which is the lowering of the metal-insulator energy barrier due to the electrostatic interaction with the electric field at a metal-insulator interface. However, the conductivity arising from the Poole–Frenkel effect is detected in presence of bulk-limited conduction (when the limiting conduction process occurs in the bulk of a material), while the Schottky current is observed when the conductivity is contact-limited (when the limiting conduction mechanism occurs at the metal-insulator interface). | 1 | Solid-state chemistry |
Li completed her undergraduate studies in China, and received her master's degree from the State University of New York at Albany.
She obtained her PhD degree in January 1990 at Cornell University under the supervision of Professor Roald Hoffmann, the 1981 Nobel Prize laureate in Chemistry. She continued to work at Cornell as a postdoc for two years (1989–1991) with Professor Francis DiSalvo before taking an academic position at Rutgers University. | 1 | Solid-state chemistry |
The frequency of light scattered by particles undergoing electrophoresis is shifted by the amount of the Doppler effect, from that of the incident light, : .
The shift can be detected by means of heterodyne optics in which the scattering light is mixed with the reference light.
The autocorrelation function of intensity of the mixed light, , can be approximately described by the following damped cosine function [7].
where is a decay constant and A, B, and C are positive constants dependent on the optical system.
Damping frequency is an observed frequency, and is the frequency difference between scattered and reference light.
where is the frequency of scattered light, the frequency of the reference light,
the frequency of incident light (laser light),
and the modulation frequency.
The power spectrum of mixed light, namely the Fourier transform of , gives a couple of Lorenz functions at having a half-width of at the half maximum.
In addition to these two, the last term in equation (1) gives another Lorenz function at
The Doppler shift of frequency and the decay constant are dependent on the geometry of the optical system and are expressed respectively by the equations.
and
where is velocity of the particles, is the amplitude of the scattering vector, and is the translational diffusion constant of particles.
The amplitude of the scattering vector is given by the equation
Since velocity is proportional to the applied electric field, , the apparent electrophoretic mobility is define by the equation
Finally, the relation between the Doppler shift frequency and mobility is given for the case of the optical configuration of Fig. 3 by the equation
where is the strength of the electric field, the refractive index of the medium, , the wavelength of the incident light in vacuum, and the scattering angle.
The sign of is a result of vector calculation and depends on the geometry of the optics.
The spectral frequency can be obtained according to Eq. (2).
When , Eq. (2) is modified and expressed as
The modulation frequency can be obtained as the damping frequency without an electric field applied.
The particle diameter is obtained by assuming that the particle is spherical. This is called the hydrodynamic diameter, .
where is Boltzmann coefficient, is the absolute temperature, and the dynamic viscosity of the surrounding fluid. | 0 | Colloidal Chemistry |
Although electronic band structures are usually associated with crystalline materials, quasi-crystalline and amorphous solids may also exhibit band gaps. These are somewhat more difficult to study theoretically since they lack the simple symmetry of a crystal, and it is not usually possible to determine a precise dispersion relation. As a result, virtually all of the existing theoretical work on the electronic band structure of solids has focused on crystalline materials. | 1 | Solid-state chemistry |
X-ray diffraction is also used due to its imaging capabilities and speed of data generation. The latter often requires revisiting and refining the preparative procedures and that are linked to the question of which phases are stable at what composition and what stoichiometry. In other words, what the phase diagram looks like. An important tool in establishing this are thermal analysis techniques like DSC or DTA and increasingly also, due to the advent of synchrotrons, temperature-dependent powder diffraction. Increased knowledge of the phase relations often leads to further refinement in synthetic procedures in an iterative way. New phases are thus characterized by their melting points and their stoichiometric domains. The latter is important for the many solids that are non-stoichiometric compounds. The cell parameters obtained from XRD are particularly helpful to characterize the homogeneity ranges of the latter. | 1 | Solid-state chemistry |
Hard soaps (), also termed soda soaps in older terminology, are categorized under soaps and are typically sodium salts of fatty acids. They vary in color from white to brownish and have a fatty acid content ranging from 72 to 75%. These soaps are typically made from lower-quality fats. Hard soaps serve as the foundation for products frequently labeled as fine soaps, which are fortified with nourishing additives, perfumes, and dyes. | 0 | Colloidal Chemistry |
Some physicists have claimed that it is possible for spin-zero particles to travel faster than the speed of light when tunnelling. This appears to violate the principle of causality, since a frame of reference then exists in which the particle arrives before it has left. In 1998, Francis E. Low reviewed briefly the phenomenon of zero-time tunnelling. More recently, experimental tunnelling time data of phonons, photons, and electrons was published by Günter Nimtz.
Other physicists, such as Herbert Winful, disputed these claims. Winful argued that the wave packet of a tunnelling particle propagates locally, so a particle can't tunnel through the barrier non-locally. Winful also argued that the experiments that are purported to show non-local propagation have been misinterpreted. In particular, the group velocity of a wave packet does not measure its speed, but is related to the amount of time the wave packet is stored in the barrier. But the problem remains that the wave function still rises inside the barrier at all points at the same time. In other words, in any region that is inaccessible to measurement, non-local propagation is still mathematically certain.
A 2020 experiment, overseen by Aephraim M. Steinberg, showed that particles should be able to tunnel at apparent speeds faster than light. | 1 | Solid-state chemistry |
Michel Pouchard (born 23 January, 1938 in Avrillé-les-Ponceaux) is a French chemist specialising in the physico-chemistry of inorganic solids. | 1 | Solid-state chemistry |
Guloy completed his undergraduate studies at the University of the Philippines in 1985. He earned his doctoral degree at the Iowa State University in 1991. His thesis topic was studying the synthesis, structure, and properties of polar intermetallic tetrelides of the rare-earth and alkaline-earth metals. Guloy performed postdoctoral research at the IBM TJ Watson Research Center under the supervision of David Mitzi where he co-discovered conducting tin halides with a layered organic-based perovskite structure. These and similar materials are the basis of perovskite solar cells. | 1 | Solid-state chemistry |
The dipolar interaction yields the most direct information with respect to structure as it makes it possible to measure the distances between the spins. The sensitivity of this interaction is however lacking and even though dipolar-based NMR crystallography makes the elucidation of structures possible, other methods are necessary to obtain high resolution structures. For these reasons much work was done to include the use other NMR observables such as chemical shift anisotropy, J-coupling and the quadrupolar interaction. These anisotropic interactions are highly sensitive to the 3D local environment making it possible to refine the structures of powdered samples to structures rivaling the quality of single crystal X-ray diffraction. These however rely on adequate methods for predicting these interactions as they do not depend in a straightforward fashion on the structure. | 1 | Solid-state chemistry |
Wilfried Umbach (Hrsg.), Kosmetik und Hygiene von Kopf bis Fuß, Wiley-VCH Verlag GmbH & Co. KGaA, 3. vollst. überarb. u. erw. Auflage (27. Juli 2012), | 0 | Colloidal Chemistry |
Standard monolayer cell culturing on tissue culture plastic has notably improved the understanding of basic cell biology, but it does not replicate the complex 3D architecture of in vivo tissue, and it can significantly modify cell properties. This often compromises experiments in basic life science, leads to misleading drug-screening results on efficacy and toxicity, and produces cells that may lack the characteristics needed for developing tissue regeneration therapies.
The future of cell culturing for fundamental studies and biomedical applications lies in the creation of multicellular structure and organization in three dimensions. Many schemes for 3D culturing are being developed or marketed, such as bio-reactors or protein-based gel environments.
A 3D cell culturing system known as the Bio-Assembler uses biocompatible polymer-based reagents to deliver magnetic nanoparticles to individual cells so that an applied magnetic driver can levitate cells off the bottom of the cell culture dish and rapidly bring cells together near the air-liquid interface. This initiates cell-cell interactions in the absence of any artificial surface or matrix. Magnetic fields are designed to rapidly form 3D multicellular structures in as little as a few hours, including expression of extracellular matrix proteins. The matrix, protein expression, and response to exogenous agents of resulting tissue show great similarity to in vivo results. | 0 | Colloidal Chemistry |
Polyvinylcarbazole is soluble in aromatic hydrocarbons, halogenated hydrocarbons and ketones. It is resistant to acids, alkalis, polar solvents and aliphatic hydrocarbons. The addition of PVK to other plastic masses increases their temperature resistance. | 1 | Solid-state chemistry |
Terbium(III) oxide, also known as terbium sesquioxide, is a sesquioxide of the rare earth metal terbium, having chemical formula . It is a p-type semiconductor, which conducts protons, which is enhanced when doped with calcium. It may be prepared by the reduction of Terbium(III,IV) oxide| in hydrogen at 1300 °C for 24 hours.
It is a basic oxide and easily dissolved to dilute acids, and then almost colourless terbium salt is formed.
: TbO + 6 H → 2 Tb + 3 HO
The crystal structure is cubic and the lattice constant is a = 1057 pm. | 1 | Solid-state chemistry |
Francesco Selmi (7 April 1817 – 13 August 1881) was an Italian chemist and patriot, one of the founders of colloid chemistry.
Selmi was born in Vignola, then part of the Duchy of Modena and Reggio. He became head of a chemistry laboratory in Modena in 1840, and a professor of chemical pharmacology and toxicology at the University of Bologna in 1867. He published the first systematic study of inorganic colloids, in particular silver chloride, Prussian blue, and sulfur, in the period 1845–50.
He died in Vignola on 13 August 1881. | 0 | Colloidal Chemistry |
The force required to separate two colloid particles can be measured using optical tweezers. This method uses a focused laser beam to apply an attractive or repulsive force on dielectric micro and nanoparticles. This technique is used with dispersion particles by applying a force which resists depletion forces. The displacement of the particles is then measured and used to find the attractive force between the particles. | 0 | Colloidal Chemistry |
Griffin's method for non-ionic surfactants as described in 1954 works as follows:
where is the molecular mass of the hydrophilic portion of the molecule, and M is the molecular mass of the whole molecule, giving a result on a scale of 0 to 20.
An HLB value of 0 corresponds to a completely lipophilic/hydrophobic molecule, and a value of 20 corresponds to a completely hydrophilic/lipophobic molecule.
The HLB value can be used to predict the surfactant properties of a molecule:
* < 10 : Lipid-soluble (water-insoluble)
* > 10 : Water-soluble (lipid-insoluble)
* 1 to 3: anti-foaming agent
* 3 to 6: W/O (water in oil) emulsifier
* 7 to 9: wetting and spreading agent
* 13 to 16: detergent
* 8 to 16: O/W (oil in water) emulsifier
* 16 to 18: solubiliser or hydrotrope | 0 | Colloidal Chemistry |
A given JT problem will have a particular point group symmetry, such as T symmetry for magnetic impurity ions in semiconductors or I symmetry for the fullerene C. JT problems are conventionally classified using labels for the irreducible representations (irreps) that apply to the symmetry of the electronic and vibrational states. For example, E ⊗ e would refer to an electronic doublet state transforming as E coupled to a vibrational doublet state transforming as e.
In general, a vibrational mode transforming as Λ will couple to an electronic state transforming as Γ if the symmetric part of the Kronecker product [Γ ⊗ Γ] contains Λ, unless Γ is a double group representation when the antisymmetric part {Γ ⊗ Γ} is considered instead. Modes which do couple are said to be JT-active.
As an example, consider a doublet electronic state E in cubic symmetry. The symmetric part of E ⊗ E is A + E. Therefore, the state E will couple to vibrational modes transforming as a and e. However, the a modes will result in the same energy shift to all states and therefore do not contribute to any JT splitting. They can therefore be neglected. The result is an E ⊗ e JT effect. This JT effect is experienced by triangular molecules X, tetrahedral molecules ML, and octahedral molecules ML when their electronic state has E symmetry.
Components of a given vibrational mode are also labelled according to their transformation properties. For example, the two components of an e mode are usually labelled and , which in octahedral symmetry transform as and respectively. | 1 | Solid-state chemistry |
Local bans have been enacted elsewhere, including in many large and small cities within the US:
* Alaska — In Alaska, the towns of Bethel, Cordova, and Seward have enacted bans.
* California — At least 128 cities in California have an existing polystyrene ban in some form. As of 2023, 12 counties — namely Alameda, Contra Costa, Los Angeles, Marin, Mendocino, Monterey, San Francisco, San Luis Obispo, San Mateo, Santa Clara, Santa Cruz, and Sonoma have bans affecting the general public. Additionally, 27 municipalities in other counties, namely Arcata, Camarillo, Carlsbad, Carpinteria, Dana Point, Davis, Del Mar, Encinitas, Goleta, Imperial Beach, Laguna Beach, Newport Beach, Oceanside, Ojai, Oxnard, Palm Springs, Port Hueneme, San Clemente, San Diego, Santa Barbara, Solana Beach, South Lake Tahoe, Thousand Oaks, Truckee, Ventura, Vista, and Yountville have bans. Together these laws cover over 20.6 million people, or about 53% of the states population. The city of Berkeley passed the nations first polystyrene foodware ban in 1988, while also requiring all disposable foodware to be degradable or recyclable.
* Connecticut — Hamden, Groton, Norwalk, Stamford, and Westport have all enacted bans. Hamden enacted the state's first ban in 1989, and continues to retain its original ordinance.
* Georgia — South Fulton banned single-use plastics in 2019. Atlanta banned polystyrene at city-owned buildings, including Hartsfield–Jackson Atlanta International Airport.
* Illinois — Oak Park and River Forest have enacted bans. In 2023, the state legislature passed a ban affecting state agencies and universities.
* Massachusetts — At least 66 municipalities have bans on polystyrene, including Abington, Acton, Amherst, Andover, Arlington, Athol, Attleboro, Brookline, Buckland, Cambridge, Chatham, Chelmsford, Concord, Dennis, Eastham, Easthampton, Essex, Fairhaven, Falmouth, Georgetown, Gloucester, Grafton, Great Barrington, Greenfield, Hadley, Hamilton, Hanson, Ipswich, Lee, Lenox, Lexington, Lincoln, Manchester-by-the-Sea, Marblehead, Maynard, Medford, Melrose, Nantucket, Newton, Northborough, Northampton, Orleans, Pittsfield, Provincetown, Raynham, Reading, Revere, Rockport, Salem, Saugus, Shrewsbury, Somerville, South Hadley, Stockbridge, Sudbury, Swampscott, Upton, Wayland, Wellfleet, Westborough, Westfield, Westford, Whitman, Williamstown, Winthrop, and Yarmouth.
* Minnesota — Minneapolis enacted a ban in 1989, and amended the largely unenforced ban in 2015. In 2017, the city of St. Louis Park effectively banned single-use polystyrene after mandating compostable, reusable, or locally recyclable packaging. Saint Paul enacted a similar provision in 2022.
* New Hampshire — Portsmouth enacted the first ban in New Hampshire in 2020.
* New Mexico — Santa Fe County passed a ban on serving food, or packing eggs, baked goods, or produce in polystyrene containers, affecting unincorporated parts of the county.
* Pennsylvania — The Boroughs of Ambler, Newtown, Swarthmore, and Townships of Montgomery, Newtown, Solebury, Tredyffrin, Upper Merion, Upper Moreland, and Uwchlan enacted bans.
* South Carolina — The city of Charleston adopted an ordinance in 2018, with the surrounding Charleston County adopting a similar ordinance the year after. | 0 | Colloidal Chemistry |
In the history of semiconductor physics, CuO is one of the most studied materials, and many experimental semiconductor applications have been demonstrated first in this material:
*Semiconductor
*Semiconductor diodes
*Phonoritons ("a coherent superposition of exciton, photon, and phonon")
The lowest excitons in CuO are extremely long lived; absorption lineshapes have been demonstrated with neV linewidths, which is the narrowest bulk exciton resonance ever observed. The associated quadrupole polaritons have low group velocity approaching the speed of sound. Thus, light moves almost as slowly as sound in this medium, which results in high polariton densities.
Another unusual feature of the ground state excitons is that all primary scattering mechanisms are known quantitatively. CuO was the first substance where an entirely parameter-free model of absorption linewidth broadening by temperature could be established, allowing the corresponding absorption coefficient to be deduced. It can be shown using CuO that the Kramers–Kronig relations do not apply to polaritons. | 1 | Solid-state chemistry |
Titanium alloys are the choice material for a diverse range of biomedical implants.
Currently employed titanium alloy implants include: hip joints,
bone screws,
knee joints, spinal fusions, shoulder joints, and bone plates. These alloys range from high ductility, commercially-pure titanium foams with high formability, to heat-treatable alloys with high strength. Titanium is well-suited for use in magnetic resonance imaging (MRI) and computed tomography (CT),
which further enhances its applicability for biomedical implant applications. | 0 | Colloidal Chemistry |
The fabrication of magnetic nanochains with controlled aspect ratio, a uniform size, and a well-defined shape is the focus of many world-leading research groups and high-tech companies. The magnetic nanochains possess attractive properties which are significant added value for many potential uses including magneto-mechanical actuation-associated nanomedicines in low and super-low frequency alternating magnetic field. Such structures are used in a variety of applications, such as imaging and drug delivery. Other applications are shown below:
* Mechanical sensors for testing the elastic moduli of biomolecules and nanostructures.
* Microactuation
* MRI imaging
* Drug delivery
* Responsive coatings | 0 | Colloidal Chemistry |
In order to achieve high ionic conductivity, electrochemical measurements are conducted in the presence of excess electrolyte. In water the electrolyte is often a simple salt such as potassium chloride. For measurements in nonaqueous solutions, salts composed of both lipophilic cations and anions are employed, e.g., tetrabutylammonium hexafluorophosphate. Even in such cases potentials are influenced by ion-pairing, an effect that is accentuated in solvents of low dielectric constant. | 1 | Solid-state chemistry |
Bamboo salt (, ) is a Korean condiment and traditional remedy. It is prepared by packing sea salt in a thick bamboo stem, and baking it nine times at high temperature using pine firewood. During the baking processes, the impurities in the salt are claimed to be removed or neutralized while its inorganic contents, such as calcium, potassium, iron, copper, and zinc are increased. | 1 | Solid-state chemistry |
Sir Frederick Charles Frank, OBE, FRS (6 March 1911 – 5 April 1998) was a British theoretical physicist. He is best known for his work on crystal dislocations, including (with Thornton Read) the idea of the Frank–Read source of dislocations. He also proposed the cyclol reaction in the mid-1930s, and made many other contributions to solid-state physics, geophysics, and the theory of liquid crystals. | 0 | Colloidal Chemistry |