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* Georges Friedel (1904) "Étude sur les groupements cristallins", Extrait du Bulletin de la Société de lIndustrie minérale', Quatrième série, Tomes III e IV. Saint-Étienne, Société de l’Imprimerie Théolier J. Thomas et C., 485 pp.
* Georges Friedel (1920) "Contribution à létude géométrique des macles", Bulletin de la S... | 1 | Crystallography |
Thermometric titrations of silver nitrate with halides and cyanide are all possible. The reaction of silver nitrate with chloride is strongly exothermic. For instance, the reaction enthalpy of Ag with Cl is a high −61.2 kJ/mol. This permits convenient determination of chloride with commonly available standard 0.1 mol/L... | 0 | Chromatography + Titration + pH indicators |
A universal indicator is a pH indicator made of a solution of several compounds that exhibit various smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. A universal indicator can be in paper form or present in a form of a solution. | 0 | Chromatography + Titration + pH indicators |
* Conventional (C)TEM-CBED: In CTEM-CBED different shape condenser apertures are used to obtain the intensity distribution over the entire Brillouin zone.
* Large Angle (LA)CBED: (LA)CBED is performed with a large incident angle, ranging from 1˚ to 10˚. LACBED makes it possible to obtain non-overlapping disks with a l... | 1 | Crystallography |
The dyes are immobilized on the column matrix effectively, since usually the dyes link to a monochlorotriazine or dichlorotriazine ring (triazine dye). This type of dyes works especially well on a support matrix with hydroxyl group. The commonly used supporting matrix would be cross-linked agarose (sepharose), sephadex... | 0 | Chromatography + Titration + pH indicators |
A crystal cluster is a group of crystals which are formed in an open space environment and exhibit euhedral crystal form determined by their internal crystal structure. A cluster of small crystals coating the walls of a cavity are called druse. | 1 | Crystallography |
* 1925 – Laboratory of crystallography at the Mineralogical Museum (Leningrad).
* 1932 – Crystallographic section of the Lomonosov Institute of Geochemistry, Mineralogy and Petrography of the USSR Academy of Sciences.
* 1937 – Crystallographic Laboratory becomes part of the Geological Group of the USSR Academy of Scien... | 1 | Crystallography |
Countercurrent chromatography and centrifugal partition chromatography are two different instrumental realization of the same liquid–liquid chromatographic theory. Countercurrent chromatography usually uses a planetary gear motion without rotary seals, while centrifugal partition chromatography uses circular rotation w... | 0 | Chromatography + Titration + pH indicators |
Abnormal or discontinuous grain growth, also referred to as exaggerated or secondary recrystallisation grain growth, is a grain growth phenomenon in which certain energetically favorable grains (crystallites) grow rapidly in a matrix of finer grains, resulting in a bimodal grain-size distribution.
In ceramic materials,... | 1 | Crystallography |
The Goldschmidt tolerance factor () is a dimensionless number that is calculated from the ratio of the ionic radii:
In an ideal cubic perovskite structure, the lattice parameter (i.e., length) of the unit cell (a) can be calculated using the following equation: | 1 | Crystallography |
In coordination chemistry and crystallography, the geometry index or structural parameter () is a number ranging from 0 to 1 that indicates what the geometry of the coordination center is. The first such parameter for 5-coordinate compounds was developed in 1984. Later, parameters for 4-coordinate compounds were develo... | 1 | Crystallography |
Iodometry in its many variations is extremely useful in volumetric analysis. Examples include the determination of copper(II), chlorate, hydrogen peroxide, and dissolved oxygen:
Available chlorine refers to chlorine liberated by the action of dilute acids on hypochlorite. Iodometry is commonly employed to determine th... | 0 | Chromatography + Titration + pH indicators |
The "hard ionization" process of electron ionization can be softened by the cooling of the molecules before their ionization, resulting in mass spectra that are richer in information. In this method named cold electron ionization (cold-EI) the molecules exit the GC column, mixed with added helium make up gas and expand... | 0 | Chromatography + Titration + pH indicators |
The volumetric titration is based on the same principles as the coulometric titration, except that the anode solution above now is used as the titrant solution. The titrant consists of an alcohol (ROH), base (B), and a known concentration of . Pyridine has been used as the base in this case.
One mole of is consumed f... | 0 | Chromatography + Titration + pH indicators |
Racemic crystallography is a technique used in structural biology where crystals of a protein molecule are developed from an equimolar mixture of an L-protein molecule of natural chirality and its D-protein mirror image. L-protein molecules consist of left-handed L-amino acids and the achiral amino acid glycine, where... | 1 | Crystallography |
Robert Travis Kennedy is an American chemist specializing in bioanalytical chemistry including liquid chromatography, capillary electrophoresis, and microfluidics. He is currently the Hobart H. Willard Distinguished University Professor of Chemistry and the chair of the department of chemistry at the University of Mich... | 0 | Chromatography + Titration + pH indicators |
Since it is accepted that ion suppression has the potential to affect the other analytical parameters of any assay, a prudent approach to any LC-MS method development should include an evaluation of ion-suppression. There are two accepted protocols by which this may be achieved, described as follows. | 0 | Chromatography + Titration + pH indicators |
The extrusion of stationary phase from the column at the end of a separation experiment by stopping rotation and pumping solvent or gas through the column was used by CCC practitioners before the term EECCC was suggested. In elution-extrusion mode (EECCC), The mobile phase is extruded after a certain point by switching... | 0 | Chromatography + Titration + pH indicators |
In this approach, the sample is spiked with a species (internal standard) which is used to normalise the response of analyte, compensating for variables at any stage of the sample preparation and analysis, including ion suppression.
It is important that the internal standard displays very similar (ideally identical) pr... | 0 | Chromatography + Titration + pH indicators |
There are two simple regular lattices that achieve this highest average density. They are called face-centered cubic (FCC) (also called cubic close packed) and hexagonal close-packed (HCP), based on their symmetry. Both are based upon sheets of spheres arranged at the vertices of a triangular tiling; they differ in how... | 1 | Crystallography |
Several software graphic tools will let you create 2D patterns using wallpaper symmetry groups. Usually you can edit the original tile and its copies in the entire pattern are updated automatically.
* [http://www.madpattern.com/ MadPattern], a free set of Adobe Illustrator templates that support the 17 wallpaper groups... | 1 | Crystallography |
In contrast with crystals, liquids have no long-range order (in particular, there is no regular lattice), so the structure factor does not exhibit sharp peaks. They do however show a certain degree of short-range order, depending on their density and on the strength of the interaction between particles. Liquids are iso... | 1 | Crystallography |
The eluent (mobile phase) should be the appropriate solvent to dissolve the polymer, should not interfere with the response of the polymer analyzed, and should wet the packing surface and make it inert to interactions with the polymers. The most common eluents for polymers that dissolve at room temperature GPC are tetr... | 0 | Chromatography + Titration + pH indicators |
A RHEED system requires an electron source (gun), photoluminescent detector screen and a sample with a clean surface, although modern RHEED systems have additional parts to optimize the technique. The electron gun generates a beam of electrons which strike the sample at a very small angle relative to the sample surface... | 1 | Crystallography |
The ancient world lacked standardized forensic practices, which enabled criminals to escape punishment. Criminal investigations and trials relied heavily on forced confessions and witness testimony. However, ancient sources do contain several accounts of techniques that foreshadow concepts in forensic science developed... | 0 | Chromatography + Titration + pH indicators |
Nickel can be titrated thermometrically using di-sodium dimethylglyoximate as titrant. The chemistry is analogous to the classic gravimetric procedure, but the time taken for a determination can be reduced from many hours to a few minutes. Potential interferences need to be considered. | 0 | Chromatography + Titration + pH indicators |
Isometries of the Euclidean plane fall into four categories (see the article Euclidean plane isometry for more information).
*Translations, denoted by T, where v is a vector in R. This has the effect of shifting the plane applying displacement vector v.
*Rotations, denoted by R, where c is a point in the plane (the cen... | 1 | Crystallography |
Initial glance, forensic intelligence may appear as a nascent facet of forensic science facilitated by advancements in information technologies such as computers, databases, and data-flow management software. However, a more profound examination reveals that forensic intelligence represents a genuine and emerging incli... | 0 | Chromatography + Titration + pH indicators |
When a crystalline material that contains atoms with uncompensated electron spins is cooled down, ordering of these spins generally occurs once the thermal energy is small enough not to overrule the interactions between neighboring spins. If the ordering does not exhibit the same symmetry as the original unit cell of t... | 1 | Crystallography |
The discreteness condition means that there is some positive real number ε, such that for every translation T in the group, the vector v has length at least ε (except of course in the case that v is the zero vector, but the independent translations condition prevents this, since any set that contains the zero vector is... | 1 | Crystallography |
In macromolecular crystallography, the term additive is used instead of adjutant. An additive can either interact directly with the protein, and become incorporated at a fixed position in the resulting crystal or have a role within the disordered solvent, that in protein crystals constitute roughly 50% of the lattice v... | 1 | Crystallography |
Quinaldine red (pronounced , abbreviated QR) is a dark green–red or black solid that does not dissolve easily in water (it is partly miscible). In addition to being used as colored indicator, quinaldine red is also used as a fluorescence probe and an agent in bleaching. | 0 | Chromatography + Titration + pH indicators |
Ion exchange chromatography can be used to separate proteins because they contain charged functional groups. The ions of interest (in this case charged proteins) are exchanged for another ions (usually H) on a charged solid support. The solutes are most commonly in a liquid phase, which tends to be water. Take for exam... | 0 | Chromatography + Titration + pH indicators |
In physics, the terms order and disorder designate the presence or absence of some symmetry or correlation in a many-particle system.
In condensed matter physics, systems typically are ordered at low temperatures; upon heating, they undergo one or several phase transitions into less ordered states.
Examples for such an... | 1 | Crystallography |
Field-flow fractionation (FFF) can be considered as an alternative to GPC, especially when particles or high molar mass polymers cause clogging of the column, shear degradation is an issue or agglomeration takes place but cannot be made visible. FFF is separation in an open flow channel without having a static phase in... | 0 | Chromatography + Titration + pH indicators |
The intense color from which the compound gets its name results from irradiation and subsequent excitation and relaxation of the extended π electron system across the R-N=N-R linked phenols. Absorption of these electrons falls in the visible region of the electromagnetic spectrum. Azo violets intense indigo color (λ 43... | 0 | Chromatography + Titration + pH indicators |
The process of crystal identification involves comparing them to images of crystals in different solvents found in published sources. Although the shape of the crystals depends on the solvent and, to a certain degree, the substance concentration, it is usually possible to recognize the fundamental crystalline forms. Ca... | 1 | Crystallography |
pHydrion is the trademarked name for a popular line of chemical test products, marketed by Micro Essential Laboratory, Inc., the original manufacturer of Hydrion and pHydrion products. The trademarked pHydrion product line comprises chemical test papers, chemical indicators, chemical test kits, chemical indicator kits,... | 0 | Chromatography + Titration + pH indicators |
Forensic science, also known as criminalistics, is the application of science principles and methods to support legal decision-making in matters of criminal and civil law.
During criminal investigation in particular, it is governed by the legal standards of admissible evidence and criminal procedure. It is a broad fiel... | 0 | Chromatography + Titration + pH indicators |
The set of all lines through the origin in three-dimensional space forms a space called the real projective plane. This plane is difficult to visualize, because it cannot be embedded in three-dimensional space.
However, one can visualize it as a disk, as follows. Any line through the origin intersects the southern hemi... | 1 | Crystallography |
Another common method of converting between fractional and Cartesian coordinates involves the use of a cell tensor which contains each of the basis vectors of the space expressed in Cartesian coordinates. | 1 | Crystallography |
Since refinement depends on finding the best fit between a calculated and experimental pattern, it is important to have a numerical figure of merit quantifying the quality of the fit. Below are the figures of merit generally used to characterize the quality of a refinement. They provide insight to how well the model fi... | 1 | Crystallography |
Polymorphism in binary metal oxides has attracted much attention because these materials are of significant economic value. One set of famous examples have the composition SiO, which form many polymorphs. Important ones include: α-quartz, β-quartz, tridymite, cristobalite, moganite, coesite, and stishovite. | 1 | Crystallography |
Sir William Herschel was one of the first to advocate the use of fingerprinting in the identification of criminal suspects. While working for the Indian Civil Service, he began to use thumbprints on documents as a security measure to prevent the then-rampant repudiation of signatures in 1858.
In 1877 at Hooghly (near K... | 0 | Chromatography + Titration + pH indicators |
Perovskite structures are adopted by many oxides that have the chemical formula ABO. The idealized form is a cubic structure (space group Pmm, no. 221) which is rarely encountered. The orthorhombic (e.g. space group Pnma, no. 62, or Amm2, no. 68) and tetragonal (e.g. space group I4/mcm, no. 140, or P4mm, no. 99) phases... | 1 | Crystallography |
Kagome () is a traditional Japanese woven bamboo pattern; its name is composed from the words kago, meaning "basket", and me, meaning "eye(s)", referring to the pattern of holes in a woven basket.
The kagome pattern is common in bamboo weaving in East Asia. In 2022, archaeologists found bamboo weaving remains at the Do... | 1 | Crystallography |
Aurin (C.I. 43800), sometimes named rosolic acid or corallin is an organic compound, forming yellowish or deep-red crystals with greenish metallic luster. It is practically insoluble in water, freely soluble in alcohol. It is soluble in strong acids to form yellow solution, or in aqueous alkalis to form carmine red sol... | 0 | Chromatography + Titration + pH indicators |
A protocrystalline phase is a distinct phase occurring during crystal growth, which evolves into a microcrystalline form. The term is typically associated with silicon films in optical applications such as solar cells. | 1 | Crystallography |
Crystal structure is described in terms of the geometry of arrangement of particles in the unit cells. The unit cell is defined as the smallest repeating unit having the full symmetry of the crystal structure. The geometry of the unit cell is defined as a parallelepiped, providing six lattice parameters taken as the le... | 1 | Crystallography |
Because of her interest in nutrition and nutrients, Coward was one of the early adopters of chromatography following its introduction in 1906-1911 by M. S. Tswett.
Carotenoids, a class of structurally similar pigment molecules that include carotenes and xanthophylls, were of particular interest in nutritional research ... | 0 | Chromatography + Titration + pH indicators |
Yellow H-A or Reactive Yellow 3 has a formula of CHClNOS and a molecular weight of 593 g/mol, containing a monochlorotriazine ring. On agarose as supporting matrix, it was seen to purify cholesteryl ester transfer protein. | 0 | Chromatography + Titration + pH indicators |
There is compelling evidence that components within some UCMs are toxic to marine organisms. The clearance rate (also known as feeding feed) of mussels was reduced by 40% following exposure to a monoaromatic UCM derived from a Norwegian crude oil. The toxicity of monoaromatic UCM components was further evidenced by an ... | 0 | Chromatography + Titration + pH indicators |
Factors influencing habit include: a combination of two or more crystal forms; trace impurities present during growth; crystal twinning and growth conditions (i.e., heat, pressure, space); and specific growth tendencies such as growth striations. Minerals belonging to the same crystal system do not necessarily exhibit ... | 1 | Crystallography |
Sample thickness can be estimated using twoBeamGUI from a convergent beam electron diffraction pattern (CBED) in two beam approximation. The procedure is based on an automated extraction of the intensity profile across the diffracted disk in the following steps:
# diffraction disk radius is determined using multi-scale... | 1 | Crystallography |
Countercurrent chromatography (CCC, also counter-current chromatography) is a form of liquid–liquid chromatography that uses a liquid stationary phase that is held in place by inertia of the molecules composing the stationary phase accelerating toward the center of a centrifuge due to centripetal force and is used to s... | 0 | Chromatography + Titration + pH indicators |
Stereographic projection is also applied to the visualization of polytopes. In a Schlegel diagram, an -dimensional polytope in is projected onto an -dimensional sphere, which is then stereographically projected onto . The reduction from to can make the polytope easier to visualize and understand. | 1 | Crystallography |
The titration process creates solutions with compositions ranging from pure acid to pure base. Identifying the pH associated with any stage in the titration process is relatively simple for monoprotic acids and bases. The presence of more than one acid or base group complicates these computations. Graphical methods, s... | 0 | Chromatography + Titration + pH indicators |
In crystallography, the basis and lattice are treated separately. For a perfect crystal the lattice gives the reciprocal lattice, which determines the positions (angles) of diffracted beams, and the basis gives the structure factor which determines the amplitude and phase of the diffracted beams:
where the sum is over... | 1 | Crystallography |
An effective sample preparation protocol, usually involving either liquid-liquid extraction (LLE) or solid phase extraction (SPE) and frequently derivatisation can remove ion suppressing species from the sample matrix prior to analysis. These common approaches may also remove other interferences, such as isobaric speci... | 0 | Chromatography + Titration + pH indicators |
Dialysis is useful for many of the same desalting and buffer exchange applications performed with gel filtration chromatography, as both methods are based on similar molecular weight cut-off limits. Gel filtration has the advantage of speed (a few minutes vs. hours for dialysis) along with the ability to remove contami... | 0 | Chromatography + Titration + pH indicators |
Ion chromatography has advanced through the accumulation of knowledge over a course of many years. Starting from 1947, Spedding and Powell used displacement ion-exchange chromatography for the separation of the rare earths. Additionally, they showed the ion-exchange separation of 14N and 15N isotopes in ammonia. At th... | 0 | Chromatography + Titration + pH indicators |
A positive test is represented by the development of red color in 15 minutes or more after addition of the reagents, indicating the presence of diacetyl, the oxidation product of acetoin. The test should be red, after standing for 1 hour because negative VP cultures may produce copper-like colour potentially resulting ... | 0 | Chromatography + Titration + pH indicators |
The chemical components of orcein were elucidated only in the 1950s by Hans Musso. The structures are shown below. A paper originally published in 1961, embodying most of Musso's work on components of orcein and litmus, was translated into English and published in 2003 in a special issue of the journal Biotechnic & His... | 0 | Chromatography + Titration + pH indicators |
In crystallography, a Strukturbericht designation or Strukturbericht type is a system of detailed crystal structure classification by analogy to another known structure. The designations were intended to be comprehensive but are mainly used as supplement to space group crystal structures designations, especially histor... | 1 | Crystallography |
Azo violet (Magneson I; p-nitrobenzeneazoresorcinol) is an azo compound with the chemical formula CHNO. It is used commercially as a violet dye and experimentally as a pH indicator, appearing yellow below pH 11, and violet above pH 13. It also turns deep blue in the presence of magnesium salt in a slightly alkaline, o... | 0 | Chromatography + Titration + pH indicators |
Phase transitions (phase changes) that help describe polymorphism include polymorphic transitions as well as melting and vaporization transitions. According to IUPAC, a polymorphic transition is "A reversible transition of a solid crystalline phase at a certain temperature and pressure (the inversion point) to another ... | 1 | Crystallography |
The first representations of perfect quasicrystalline patterns can be found in several early Islamic works of art and architecture such as the Gunbad-i-Kabud tomb tower, the Darb-e Imam shrine and the Al-Attarine Madrasa. On July 16, 1945, in Alamogordo, New Mexico, the Trinity nuclear bomb test produced icosahedral qu... | 1 | Crystallography |
:Automated diffraction tomography (ADT) uses software to collect diffraction patterns over a series of slight tilt increments. In this way, a three-dimensional (tomographic) data set of reciprocal lattice intensities can be generated and used for structure determination. By coupling this technique with PED, the range a... | 1 | Crystallography |
Supercells are also commonly used in computational models of crystal defects to allow the use of periodic boundary conditions. | 1 | Crystallography |
For membrane proteins, the situation is more complicated because the system that is being crystallized is not the membrane protein itself but the micellar system in which the membrane protein is embedded.
The size of the protein-detergent mixed micelles are affected by both additives and detergents which will strongly ... | 1 | Crystallography |
To perform microcrystallization, a small piece of lichen is extracted using acetone or other solvents, filtered, and evaporated to yield a residue. The residue is transferred to a microscope slide, and a drop of microcrystallization reagent is added before capping with a cover glass. Commonly used reagents include GAW ... | 1 | Crystallography |
In mathematics and solid state physics, the first Brillouin zone (named after Léon Brillouin) is a uniquely defined primitive cell in reciprocal space. In the same way the Bravais lattice is divided up into Wigner–Seitz cells in the real lattice, the reciprocal lattice is broken up into Brillouin zones. The boundaries... | 1 | Crystallography |
The reciprocal lattice to an FCC lattice is the body-centered cubic (BCC) lattice, with a cube side of .
Consider an FCC compound unit cell. Locate a primitive unit cell of the FCC; i.e., a unit cell with one lattice point. Now take one of the vertices of the primitive unit cell as the origin. Give the basis vectors of... | 1 | Crystallography |
A chloridometer is a measuring instrument used to determine the concentration of chloride ions (Cl) in a solution. It uses a process known as coulometric titration or amperostatic coulometry, the accepted electrochemistry reference method to determine the concentration of chloride in biological fluids, including blood ... | 0 | Chromatography + Titration + pH indicators |
Isometries requiring an odd number of mirrors — reflection and glide reflection — always reverse left and right. The even isometries — identity, rotation, and translation — never do; they correspond to rigid motions, and form a normal subgroup of the full Euclidean group of isometries. Neither the full group nor the ev... | 1 | Crystallography |
Dozens of congenital metabolic diseases also known as inborn errors of metabolism (IEM) are now detectable by newborn screening tests, especially the testing using gas chromatography–mass spectrometry. GC–MS can determine compounds in urine even in minor concentration. These compounds are normally not present but appe... | 0 | Chromatography + Titration + pH indicators |
A comprehensive article on the modern trends and best practices of mobile phase selection in reversed-phase chromatography was published by Boyes and Dong. A mobile phase in reversed-phase chromatograpy consists of mixtures of water or aqueous buffers, to which organic solvents are added, to elute analytes from a rever... | 0 | Chromatography + Titration + pH indicators |
Similar to bromocresol green, the structure of bromocresol purple changes with pH. Changing the level of acidity causes a shift in the equilibrium between two different structures that have different colors. In near-neutral or alkaline solution, the chemical has a sulfonate structure that gives the solution a purple co... | 0 | Chromatography + Titration + pH indicators |
In October 2016, Christopher Monroe at the University of Maryland claimed to have created the worlds first discrete time crystal. Using the ideas proposed by Yao et al., his team trapped a chain of Yb ions in a Paul trap, confined by radio-frequency electromagnetic fields. One of the two spin states was selected by a p... | 1 | Crystallography |
The designations were established by the journal Zeitschrift für Kristallographie – Crystalline Materials, which published its first round of supplemental reviews under the name Strukturbericht from 1913-1928. These reports were collected into a book published in 1931 by Paul Peter Ewald and Carl Hermann which became V... | 1 | Crystallography |
Crystal violet can be used as an alternative to Coomassie brilliant blue (CBB) in staining of proteins separated by SDS-PAGE, reportedly showing a 5x improved sensitivity vs CBB. | 0 | Chromatography + Titration + pH indicators |
Sunset yellow is used in foods, condoms, cosmetics, and drugs. Sunset yellow FCF is used as an orange or yellow-orange dye. For example, it is used in candy, desserts, snacks, sauces, and preserved fruits.
Sunset yellow is often used in conjunction with E123, amaranth, to produce a brown colouring in both chocolates a... | 0 | Chromatography + Titration + pH indicators |
The point groups are named according to their component symmetries. There are several standard notations used by crystallographers, mineralogists, and physicists.
For the correspondence of the two systems below, see crystal system. | 1 | Crystallography |
The crystallographic point group or crystal class is the mathematical group comprising the symmetry operations that leave at least one point unmoved and that leave the appearance of the crystal structure unchanged. These symmetry operations include
*Reflection, which reflects the structure across a reflection plane
*Ro... | 1 | Crystallography |
The coupling of MS with LC systems is attractive because liquid chromatography can separate delicate and complex natural mixtures, which chemical composition needs to be well established (e.g., biological fluids, environmental samples, and drugs). Further, LC–MS has applications in volatile explosive residue analysis. ... | 0 | Chromatography + Titration + pH indicators |
Homoepitaxy is a kind of epitaxy performed with only one material, in which a crystalline film is grown on a substrate or film of the same material. This technology is often used to grow a more pure film than the substrate and to fabricate layers with different doping levels. In academic literature, homoepitaxy is ofte... | 1 | Crystallography |
Cerimetry or cerimetric titration, also known as cerate oximetry, is a method of volumetric chemical analysis developed by Ion Atanasiu. It is a redox titration in which an iron(II)–1,10-phenanthroline complex (ferroin) color change indicates the end point. Ferroin can be reversibly discolored in its oxidized form upon... | 0 | Chromatography + Titration + pH indicators |
Two-dimensional separations can be carried out in gas chromatography or liquid chromatography. Various different coupling strategies have been developed to "resample" from the first column into the second. Some important hardware for two-dimensional separations are Deans' switch and Modulator, which selectively transf... | 0 | Chromatography + Titration + pH indicators |
In March 1951, the British Tabulating Machine Company (BTM) sent a team to Andrew Booths workshop. They then used his design to create the Hollerith Electronic Computer 1 (HEC 1) before the end of 1951. The computer was a direct copy of Andrew Booths circuits with extra Input/output interfaces. The HEC 2 was the HEC 1 ... | 1 | Crystallography |
Rotations, denoted by R, where c is a point in the plane (the centre of rotation), and θ is the angle of rotation. In terms of coordinates, rotations are most easily expressed by breaking them up into two operations. First, a rotation around the origin is given by
These matrices are the orthogonal matrices (i.e. each i... | 1 | Crystallography |
The subgroup structure suggests another way to compose an arbitrary isometry:
: Pick a fixed point, and a mirror through it.
# If the isometry is odd, use the mirror; otherwise do not.
# If necessary, rotate around the fixed point.
# If necessary, translate.
This works because translations are a normal subgroup of the ... | 1 | Crystallography |
right|thumb|Example and diagram for p3
left|thumb|Cell structure for p3
* Orbifold signature:
* Coxeter notation: [(3,3,3)] or [3]
* Lattice: hexagonal
* Point group: C
* The group p3 has three different rotation centres of order three (120°), but no reflections or glide reflections.
Imagine a tessellation of the plan... | 1 | Crystallography |
In crystallography, a fractional coordinate system is used in order to better reflect the symmetry of the underlying lattice of a crystal pattern (or any other periodic pattern in space). In a fractional coordinate system the basis vectors of the coordinate system are chosen to be lattice vectors and the basis is then ... | 1 | Crystallography |
*Glucose – 5 g/L
*Dipotassium phosphate – 5 g/L
*Proteose Peptone – 5 g/L
*Distilled water – 1000 mL
pH – 6.9 | 0 | Chromatography + Titration + pH indicators |
There are seven different kinds of lattice systems, and each kind of lattice system has four different kinds of centerings (primitive, base-centered, body-centered, face-centered). However, not all of the combinations are unique; some of the combinations are equivalent while other combinations are not possible due to s... | 1 | Crystallography |
Initially these were described as ternary RE-B-Si compounds, but later carbon was included to improve the structure description that resulted in a quaternary RE-B-C-Si composition. REBCSi (RE=Y and Gd–Lu) have a unique crystal structure with two units – a cluster of B icosahedra and a Si ethane-like complex – and one b... | 1 | Crystallography |
A "strong" ion exchanger will not lose the charge on its matrix once the column is equilibrated and so a wide range of pH buffers can be used. "Weak" ion exchangers have a range of pH values in which they will maintain their charge. If the pH of the buffer used for a weak ion exchange column goes out of the capacity ra... | 0 | Chromatography + Titration + pH indicators |
In geophysics, a common assumption is that the rock formations of the crust are locally polar anisotropic (transversely isotropic); this is the simplest case of geophysical interest. Backus upscaling is often used to determine the effective transversely isotropic elastic constants of layered media for long wavelength ... | 1 | Crystallography |
The growth (starting materials, flux, and crucible) are heated to form a complete liquid solution. The growth is cooled to a temperature where the solution is fully saturated. Further cooling causes crystals to precipitate from the solution, lowering the concentration of starting materials in solution, and lowering the... | 1 | Crystallography |
Overshot titrations are a common phenomenon, and refer to a situation where the volume of titrant added during a chemical titration exceeds the amount required to reach the equivalence point. This excess titrant leads to an outcome where the solution becomes slightly more alkaline or over-acidified.
Overshooting the eq... | 0 | Chromatography + Titration + pH indicators |
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