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Previous analysis focused only on diffraction from a perfectly flat surface of a crystal surface. However, non-flat surfaces add additional diffraction conditions to RHEED analysis.
Streaked or elongated spots are common to RHEED patterns. As Fig 3 shows, the reciprocal lattice rods with the lowest orders intersect the... | 1 | Crystallography |
Time resolved crystallography utilizes X-ray crystallography imaging to visualize reactions in four dimensions (x, y, z and time). This enables the studies of dynamical changes that occur in for example enzymes during their catalysis. The time dimension is incorporated by triggering the reaction of interest in the crys... | 1 | Crystallography |
A thermometric titration is one of a number of instrumental titration techniques where endpoints can be located accurately and precisely without a subjective interpretation on the part of the analyst as to their location. Enthalpy change is arguably the most fundamental and universal property of chemical reactions, so ... | 0 | Chromatography + Titration + pH indicators |
Not only volume crystals can be imaged by topography, but also crystalline layers on a foreign substrate. For very thin layers, the scattering volume and thus the diffracted intensities are very low. In these cases, topographic imaging is therefore a rather demanding task, unless incident beams with very high intensiti... | 1 | Crystallography |
Environmental UCMs result from highly degraded petroleum hydrocarbons and once formed they can stay largely unchanged in sediments for many years. For example, in 1969 a diesel oil spill contaminated saltmarsh sediment within Wild Harbor River, US; by 1973 only a baseline hump was observed, which remained largely unch... | 0 | Chromatography + Titration + pH indicators |
Polytypes are a special case of polymorphs, where multiple close-packed crystal structures differ in one dimension only. Polytypes have identical close-packed planes, but differ in the stacking sequence in the third dimension perpendicular to these planes. Silicon carbide (SiC) has more than 170 known polytypes, altho... | 1 | Crystallography |
Transformation and annealing twinning takes place when a cooling crystal experiences a displacive polymorphic transition. For example, leucite has an isometric crystal structure above about , but becomes tetragonal below this temperature. Any one of the three original axes of a crystal can become the long axis when th... | 1 | Crystallography |
The micelle velocity is defined by:
where is the electrophoretic velocity of a micelle.
The retention time of a given sample should depend on the capacity factor, :
where is the total number of moles of solute in the micelle and is the total moles in the aqueous phase. The retention time of a solute should then be... | 0 | Chromatography + Titration + pH indicators |
In a highly basic solution, phenolphthalein's slow change from pink to colorless as it is converted to its Ph(OH) form is used in chemistry classes for the study of reaction kinetics. | 0 | Chromatography + Titration + pH indicators |
Another approach to evaluation of ion suppression is to make a comparison between:
* Detector response of calibration standard (either aqueous or in another suitable solvent) - This gives the best case scenario for detector response, i.e. under conditions of zero ion suppression
* Pre-prepared sample matrix spiked with... | 0 | Chromatography + Titration + pH indicators |
* [http://www.piercenet.com/method/desalting-gel-filtration#gelfiltration Animation of desalting using gel filtration chromatography] | 0 | Chromatography + Titration + pH indicators |
In the sintering of ceramic materials, abnormal grain growth is often viewed as an undesirable phenomenon because rapidly growing grains may lower the hardness of the bulk material through Hall-Petch-type effects. However, the controlled introduction of dopants to bring about controlled AGG may be used to impart fibre-... | 1 | Crystallography |
HPLC detectors fall into two main categories: universal or selective. Universal detectors typically measure a bulk property (e.g., refractive index) by measuring a difference of a physical property between the mobile phase and mobile phase with solute while selective detectors measure a solute property (e.g., UV-Vis ab... | 0 | Chromatography + Titration + pH indicators |
The basis vectors of unit cell U can be transformed to basis vectors of supercell S by linear transformation
where is a transformation matrix. All elements should be integers with (with the transformation preserves volume). For example, the matrix
transforms a primitive cell to body-centered. Another particular ... | 1 | Crystallography |
At the beginning of the run, a mixture of solutes to be separated is applied to the column, under conditions selected to promote high retention. The higher-affinity solutes are preferentially retained near the head of the column, with the lower-affinity solutes moving farther downstream. The fastest moving component ... | 0 | Chromatography + Titration + pH indicators |
A system is said to present annealed disorder when some parameters entering its definition are random variables, but whose evolution is related to that of the degrees of freedom defining the system. It is defined in opposition to quenched disorder, where the random variables may not change their values.
Systems with an... | 1 | Crystallography |
If the chromatographic separation can be modified to prevent coelution of suppressing species then other approaches need not be considered. The effect of chromatographic modification may be evaluated using the detector response monitoring under constant infusion approach described previously. | 0 | Chromatography + Titration + pH indicators |
A solution containing the analyte, A, in the presence of some conductive buffer. If an electrolytic potential is applied to the solution through a working electrode, then the measured current depends (in part) on the concentration of the analyte. Measurement of this current can be used to determine the concentration ... | 0 | Chromatography + Titration + pH indicators |
The (oral, mouse) is 80 mg/kg. Rats fed malachite green experience "a dose-related increase in liver DNA adducts" along with lung adenomas. Leucomalachite green causes an "increase in the number and severity of changes". As leucomalachite green is the primary metabolite of malachite green and is retained in fish muscl... | 0 | Chromatography + Titration + pH indicators |
In four dimensions, there are 64 Bravais lattices. Of these, 23 are primitive and 41 are centered. Ten Bravais lattices split into enantiomorphic pairs. | 1 | Crystallography |
An emulator for the APEXC series has been developed by MESS. They describe its functioning as follows:
<blockquote>The APEXC is an incredibly simple machine.
<br/>
Instruction and data words are always 32 bits long. The processor uses integer arithmetic with 2's complement representation. Addresses are 10 bits long. Th... | 1 | Crystallography |
The crystallographic restriction theorem can be formulated in terms of isometries of Euclidean space. A set of isometries can form a group. By a discrete isometry group we will mean an isometry group that maps each point to a discrete subset of R, i.e. the orbit of any point is a set of isolated points. With this termi... | 1 | Crystallography |
Grain boundaries are interfaces where crystals of different orientations meet. A grain boundary is a single-phase interface, with crystals on each side of the boundary being identical except in orientation. The term "crystallite boundary" is sometimes, though rarely, used. Grain boundary areas contain those atoms that ... | 1 | Crystallography |
CBED was first introduced in 1939 by Kossel and Möllenstedt. The development of the Field Emission Gun (FEG) in the 1970s, the Scanning Transmission Electron Microscopy (STEM), energy filtering devices and so on, made possible smaller probe diameters and larger convergence angles, and all this made CBED more popular. I... | 1 | Crystallography |
Before exploring Rietveld refinement, it is necessary to establish a greater understanding of powder diffraction data and what information is encoded therein in order to establish a notion of how to create a model of a diffraction pattern, which is of course necessary in Rietveld refinement. A typical diffraction patte... | 1 | Crystallography |
Long-range order characterizes physical systems in which remote portions of the same sample exhibit correlated behavior.
This can be expressed as a correlation function, namely the spin-spin correlation function:
where s is the spin quantum number and x is the distance function within the particular system.
This functi... | 1 | Crystallography |
Chloridometers are used to determine the concentration of chloride ions in biological fluids. For example, fish plasma chloride ion concentration is measured to gauge the effects of stress on osmoregulation in aquacultures. A small quantity of plasma (10 μL) combined with an acid reagent results in a chemical reaction ... | 0 | Chromatography + Titration + pH indicators |
A primitive cell is a unit cell that contains exactly one lattice point. For unit cells generally, lattice points that are shared by cells are counted as of the lattice points contained in each of those cells; so for example a primitive unit cell in three dimensions which has lattice points only at its eight vertice... | 1 | Crystallography |
The Le Bail method extracts intensities (I) from powder diffraction data. This is done in order to find intensities that are suitable to determine the atomic structure of a crystalline material and to refine the unit cell and has the added advantage of checking phase-purity. Generally, the intensities of powder diffrac... | 1 | Crystallography |
Due to their high photoluminescence quantum efficiencies, perovskites may find use in light-emitting diodes (LEDs). Although the stability of perovskite LEDs is not yet as good as III-V or organic LEDs, there is ongoing research to solve this problem, such as incorporating organic molecules or potassium dopants in pero... | 1 | Crystallography |
Aurin may cause eye, skin, and respiratory tract irritation. Ingestion and inhalation should be avoided.
Aurin was reported to have endocrine disruptor chemical (EDC) properties. | 0 | Chromatography + Titration + pH indicators |
Only the CHO+ ions formed from the ionization of carbon compounds are detected. Thus, the non-methane byproducts of the reactions are not detected by the FID.
Since every compound goes through the catalyst bed in the reactor, it can alter certain substances that might be harmful or negatively affect the efficiency and... | 0 | Chromatography + Titration + pH indicators |
The principle of the Rietveld method is to minimize a function which analyzes the difference between a calculated profile and the observed data . Rietveld defined such an equation as:
where is the statistical weight and is an overall scale factor such that . | 1 | Crystallography |
Certain nonlinear optical phenomena such as the electro-optic effect cause a variation of a medium's permittivity tensor when an external electric field is applied, proportional (to lowest order) to the strength of the field. This causes a rotation of the principal axes of the medium and alters the behaviour of light t... | 1 | Crystallography |
Tairus (, a portmanteau of Тайско (Thai) and Русский (Russian)) is a synthetic gemstone manufacturer. It was formed in 1989 as part of Mikhail Gorbachev's perestroika initiative to establish a joint venture between the Russian Academy of Sciences and Tairus Created Gems Co Ltd. of Bangkok, Thailand. Today Tairus is a m... | 1 | Crystallography |
Faster GC methods have shorter times but Kovats indexes of the compounds may be conserved if proper method translation is applied.
Temperatures of the temperature program stay the same, but ramps and times change when using a smaller column or faster carrier gas.
If column dimensions Length×diameter×film are divided ... | 0 | Chromatography + Titration + pH indicators |
Aqueous normal-phase chromatography (ANP) is a chromatographic technique that involves the mobile phase compositions and polarities between reversed-phase chromatography (RP) and normal-phase chromatography (NP), while the stationary phases are polar. | 0 | Chromatography + Titration + pH indicators |
The discovery of paper chromatography in 1943 by Martin and Synge provided, for the first time, the means of surveying constituents of plants and for their separation and identification. Erwin Chargaff credits in Weintraub's history of the man the 1944 article by Consden, Gordon and Martin. There was an explosion of ac... | 0 | Chromatography + Titration + pH indicators |
There are disadvantages to GPC, however. First, there is a limited number of peaks that can be resolved within the short time scale of the GPC run. Also, as a technique GPC requires around at least a 10% difference in molecular weight for a reasonable resolution of peaks to occur. In regards to polymers, the molecular ... | 0 | Chromatography + Titration + pH indicators |
The reds, purples, and their blended combinations responsible for autumn foliage are derived from anthocyanins. Unlike carotenoids, anthocyanins are not present in the leaf throughout the growing season, but are produced actively, toward the end of summer. They develop in late summer in the sap of leaf cells, resulting... | 0 | Chromatography + Titration + pH indicators |
By using CBED, the following information can be obtained:
*parameters of the crystal lattice, sample thickness
*strain distribution
*defects such as stacking faults, dislocations, grain boundaries, three-dimensional deformations, lattice displacements
*crystal symmetry information - by looking at the symmetries that a... | 1 | Crystallography |
In chemical ionization (CI) a reagent gas, typically methane or ammonia is introduced into the mass spectrometer. Depending on the technique (positive CI or negative CI) chosen, this reagent gas will interact with the electrons and analyte and cause a soft ionization of the molecule of interest. A softer ionization fr... | 0 | Chromatography + Titration + pH indicators |
Coward was born on 2 July 1885 in Blackburn, Lancashire. She studied Botany and graduated M.Sc. from University of Manchester. After a few years, she joined University College London to study biochemistry and perform research under J. C. Drummond on Vitamin A, paving the way for her to be nominated to the Fellow of the... | 0 | Chromatography + Titration + pH indicators |
Ordinarily, Miller indices are always integers by definition, and this constraint is physically significant. To understand this, suppose that we allow a plane (abc) where the Miller "indices" a, b and c (defined as above) are not necessarily integers.
If a, b and c have rational ratios, then the same family of planes c... | 1 | Crystallography |
The CRFs in thin layer chromatography characterize the equal-spreading of the spots. The ideal case, when the RF of the spots are uniformly distributed in <0,1> range (for example 0.25,0.5 and 0.75 for three solutes) should be characterized as the best situation possible.
The simplest criteria are and product (Wang e... | 0 | Chromatography + Titration + pH indicators |
Let be an orientation-preserving rigid motion of R. The set of these transformations is a subgroup of Euclidean motions known as the special Euclidean group SE(3). These rigid motions are defined by transformations of x in R given by
consisting of a three-dimensional rotation A followed by a translation by the vector ... | 1 | Crystallography |
The predecessor of modern countercurrent chromatography theory and practice was countercurrent distribution (CCD). The theory of CCD was described in the 1930s by Randall and Longtin. Archer Martin and Richard Laurence Millington Synge developed the methodology further during the 1940s. Finally, Lyman C. Craig introduc... | 0 | Chromatography + Titration + pH indicators |
The sublimation sandwich method (also called the sublimation sandwich process and the sublimation sandwich technique) is a kind of physical vapor deposition used for creating man-made crystals. Silicon carbide is the most common crystal grown this way, though others crystals may also be created with it (notably galliu... | 1 | Crystallography |
The primitive unit cell for the body-centered cubic crystal structure contains several fractions taken from nine atoms (if the particles in the crystal are atoms): one on each corner of the cube and one atom in the center. Because the volume of each of the eight corner atoms is shared between eight adjacent cells, each... | 1 | Crystallography |
It is used as a pH indicator and as a tracking dye for DNA agarose gel electrophoresis. It can be used in its free acid form (light brown solid), or as a sodium salt (dark green solid). It is also an inhibitor of the prostaglandin E transport protein. Additional applications include use in sol-gel matrices, the detecti... | 0 | Chromatography + Titration + pH indicators |
The primary goal of crystallography is to determine the three dimensional arrangement of atoms in a crystalline material. While historically, x-ray crystallography has been the predominant experimental method used to solve crystal structures ab initio, the advantages of precession electron diffraction make it one of th... | 1 | Crystallography |
Red HE-3B or Reactive Red 120 has a formula of CHClNOS and a molecular weight of 1338.1 g/mol, containing two monochlorotriazine rings. It is highly soluble in water. The dehydrogenases binding ability of Red HE-3B is greater to NADP+ dependent dehydrogenases than NAD+ dependent dehydrogenases, vice versa for Cibacron ... | 0 | Chromatography + Titration + pH indicators |
In chromatography, resolution is a measure of the separation of two peaks of different retention time t in a chromatogram. | 0 | Chromatography + Titration + pH indicators |
In the low- limit, as the system is probed over large length scales, the structure factor contains thermodynamic information, being related to the isothermal compressibility of the liquid by the compressibility equation: | 1 | Crystallography |
Ion-exchange chromatography (IEC) or ion chromatography (IC) is an analytical technique for the separation and determination of ionic solutes in aqueous samples from environmental and industrial origins such as metal industry, industrial waste water, in biological systems, pharmaceutical samples, food, etc. Retention i... | 0 | Chromatography + Titration + pH indicators |
Bilbao Crystallographic Server is an open access website offering online crystallographic database and programs aimed at analyzing, calculating and visualizing problems of structural and mathematical crystallography, solid state physics and structural chemistry. Initiated in 1997 by the Materials Laboratory of the Depa... | 1 | Crystallography |
In X-ray crystallography, a difference density map or Fo–Fc map shows the spatial distribution of the difference between the measured electron density of the crystal and the electron density explained by the current model.
A way to compute this map has been formulated for cyro-EM. | 1 | Crystallography |
Density functional theory seeks to solve for an approximate form of the electronic density of a system. In general, atoms are split into ionic cores and valence electrons. The ionic cores (nuclei plus non-bonding electrons) are assumed to be stable and are treated as a single object. Each valence electron is treated... | 1 | Crystallography |
Centrifugal partition chromatography does not uses any solid stationary phase, so it guarantees a cost-effective separation for the highest industrial levels. As opposed to countercurrent chromatography, it is possible to get very high flow rates (for example 10 liters / min) with active stationary phase ratio of >80%,... | 0 | Chromatography + Titration + pH indicators |
Ion-exchange chromatography separates molecules based on their respective charged groups. Ion-exchange chromatography retains analyte molecules on the column based on coulombic (ionic) interactions. The ion exchange chromatography matrix consists of positively and negatively charged ions. Essentially, molecules underg... | 0 | Chromatography + Titration + pH indicators |
The relationship between fractional and Cartesian coordinates can be described by the matrix transformation :
Similarly, the Cartesian coordinates can be converted back to fractional coordinates using the matrix transformation : | 1 | Crystallography |
Transition metal sulfates form a variety of hydrates, each of which crystallizes in only one form. The sulfate group often binds to the metal, especially for those salts with fewer than six aquo ligands. The heptahydrates, which are often the most common salts, crystallize as monoclinic and the less common orthorhomb... | 1 | Crystallography |
After the last solute has been eluted, it is necessary to strip the displacer from the column. Since the displacer was chosen for high affinity, this can pose a challenge. On reverse-phase materials, a wash with a high percentage of organic solvent may suffice. Large pH shifts are also often employed. One effective ... | 0 | Chromatography + Titration + pH indicators |
Columnar structures were first studied in botany due to their diverse appearances in plants. D'Arcy Thompson analysed such arrangement of plant parts around the stem in his book "On Growth and Form" (1917). But they are also of interest in other biological areas, including bacteria, viruses, microtubules, and the notoc... | 1 | Crystallography |
By 1982 the technology was sufficiently advanced for the technique to be called "high-speed" countercurrent chromatography (HSCCC). Peter Carmeci initially commercialized the PC Inc. Ito Multilayer Coil Separator/Extractor which utilized a single bobbin (onto which the coil is wound) and a counterbalance, plus a set of... | 0 | Chromatography + Titration + pH indicators |
Originally, n was held to have an integer value between 1 and 4, which reflected the nature of the transformation in question. In the derivation above, for example, the value of 4 can be said to have contributions from three dimensions of growth and one representing a constant nucleation rate. Alternative derivations e... | 1 | Crystallography |
Experimentally it was determined that extent of gas adsorption varies directly with pressure, and then it directly varies with pressure raised to the power until saturation pressure is reached. Beyond that point, the rate of adsorption saturates even after applying higher pressure. Thus, the Freundlich adsorption iso... | 0 | Chromatography + Titration + pH indicators |
With hexagonal and rhombohedral lattice systems, it is possible to use the Bravais–Miller system, which uses four indices (h k i ℓ) that obey the constraint
: h + k + i = 0.
Here h, k and ℓ are identical to the corresponding Miller indices, and i is a redundant index.
This four-index scheme for labeling planes in a hex... | 1 | Crystallography |
From 1943 on, Booth started working on the determination of crystal structures using X-ray diffraction data. The computations involved were extremely tedious and there was ample incentive for automating the process and he developed an analogue computer to compute the reciprocal spacings of the diffraction pattern.
In... | 1 | Crystallography |
Anthocyanins may be used as pH indicators because their color changes with pH; they are red or pink in acidic solutions (pH < 7), purple in neutral solutions (pH ≈ 7), greenish-yellow in alkaline solutions (pH > 7), and colorless in very alkaline solutions, where the pigment is completely reduced. | 0 | Chromatography + Titration + pH indicators |
There are several ways to retrieve the lost phases. The phase problem must be solved in x-ray crystallography, neutron crystallography, and electron crystallography.
Not all of the methods of phase retrieval work with every wavelength (x-ray, neutron, and electron) used in crystallography. | 1 | Crystallography |
The use of a solvent gradient is very well developed in column chromatography but is less common in CCC. A solvent gradient is produced by increasing (or decreasing) the polarity of the mobile phase during the separation to achieve optimal resolution across a wider range of polarities. For example, a methanol-water mob... | 0 | Chromatography + Titration + pH indicators |
The absorbance pattern responsible for the red color of anthocyanins may be complementary to that of green chlorophyll in photosynthetically active tissues such as young Quercus coccifera leaves. It may protect the leaves from attacks by herbivores that may be attracted by green color. | 0 | Chromatography + Titration + pH indicators |
The art of cutting a gem is an exacting procedure performed on a faceting machine. The ideal product of facet cutting is a gemstone that displays a pleasing balance of internal reflections of light known as brilliance, strong and colorful dispersion which is commonly referred to as "fire", and brightly colored flashes ... | 1 | Crystallography |
The word "titration" descends from the French word titrer (1543), meaning the proportion of gold or silver in coins or in works of gold or silver; i.e., a measure of fineness or purity. Tiltre became titre, which thus came to mean the "fineness of alloyed gold", and then the "concentration of a substance in a given sa... | 0 | Chromatography + Titration + pH indicators |
The spatial resolution achievable in topographic images can be limited by one or several of three factors:
the resolution (grain or pixel size) of the detector, the experimental geometry, and intrinsic diffraction effects.
First, the spatial resolution of an image can obviously not be better than the grain size (in the... | 1 | Crystallography |
In general, a geometric lattice is an infinite, regular array of vertices (points) in space, which can be modelled vectorially as a Bravais lattice. Some lattices may be skew, which means that their primary lines may not necessarily be at right angles. In reciprocal space, a reciprocal lattice is defined as the set of ... | 1 | Crystallography |
There was only one proven polymorph Form I of aspirin, though the existence of another polymorph was debated since the 1960s, and one report from 1981 reported that when crystallized in the presence of aspirin anhydride, the diffractogram of aspirin has weak additional peaks. Though at the time it was dismissed as mere... | 1 | Crystallography |
The fundamental resolution equation is used in chromatography to help relate adjustable chromatographic parameters to resolution, and is as follows:
R = [N/4][(α-1)/α][k/(1+k)], where
N = Number of theoretical plates
α = Selectivity Term = k/k
The [N/4] term is the column factor, the [(α-1)/α] term is the thermodynamic... | 0 | Chromatography + Titration + pH indicators |
By recording the ionic positions at each time step, one can observe how far, on average, each ion has moved from its original position. The mean squared displacement of each ion type is related to the diffusion coefficient for a particle undergoing Brownian motion. | 1 | Crystallography |
Geometric phase analysis is a method of digital signal processing used to determine crystallographic quantities such as d-spacing or strain from high-resolution transmission electron microscope images. The analysis needs to be performed using specialized computer program. | 1 | Crystallography |
In crystallography, atomic packing factor (APF), packing efficiency, or packing fraction is the fraction of volume in a crystal structure that is occupied by constituent particles. It is a dimensionless quantity and always less than unity. In atomic systems, by convention, the APF is determined by assuming that atoms a... | 1 | Crystallography |
Aqueous normal-phase chromatography (ANP) is also called hydrophilic interaction liquid chromatography (HILIC). This is a chromatographic technique which encompasses the mobile phase region between reversed-phase chromatography (RP) and organic normal phase chromatography (ONP). HILIC is used to achieve unique selectiv... | 0 | Chromatography + Titration + pH indicators |
Since the diameter of the probing convergent beam is smaller than in the case of a parallel beam, most of the information in the CBED pattern is obtained from very small regions, which other methods cannot reach. For example, in Selected Area Electron Diffraction (SAED), where a parallel beam illumination is used, the ... | 1 | Crystallography |
Euhedral crystals have flat faces with sharp angles. The flat faces (also called facets) are oriented in a specific way relative to the underlying atomic arrangement of the crystal: They are planes of relatively low Miller index. This occurs because some surface orientations are more stable than others (lower surface e... | 1 | Crystallography |
As a separation technique, GPC has many advantages. First of all, it has a well-defined separation time due to the fact that there is a final elution volume for all unretained analytes. Additionally, GPC can provide narrow bands, although this aspect of GPC is more difficult for polymer samples that have broad ranges o... | 0 | Chromatography + Titration + pH indicators |
In linear elasticity, the stress and strain are related by Hooke's law, i.e.,
or, using Voigt notation,
The condition for material symmetry in linear elastic materials is.
where | 1 | Crystallography |
Informally, a Euclidean plane isometry is any way of transforming the plane without "deforming" it. For example, suppose that the Euclidean plane is represented by a sheet of transparent plastic sitting on a desk. Examples of isometries include:
* Shifting the sheet one inch to the right.
* Rotating the sheet by ten de... | 1 | Crystallography |
A Euclidean graph in three-dimensional space is a pair (V, E), where V is a set of vertices (sometimes called points or nodes) and E is a set of edges (sometimes called bonds or spacers) where each edge joins two vertices. There is a tendency in the polyhedral and chemical literature to refer to geometric graphs as net... | 1 | Crystallography |
A post–September 11 development, explosive detection systems have become a part of all US airports. These systems run on a host of technologies, many of them based on GC–MS. There are only three manufacturers certified by the FAA to provide these systems, one of which is Thermo Detection (formerly Thermedics), which pr... | 0 | Chromatography + Titration + pH indicators |
An example of back titration, the Volhard method, named after Jacob Volhard, involves the addition of excess silver nitrate to the analyte; the silver chloride is filtered, and the remaining silver nitrate is titrated against ammonium thiocyanate, with ferric ammonium sulfate as an indicator which forms blood-red [[Thi... | 0 | Chromatography + Titration + pH indicators |
The translational invariance of a crystal lattice is described by a set of unit cell, direct lattice basis vectors (contravariant or polar) called a, b, and c, or equivalently by the lattice parameters, i.e. the magnitudes of the vectors, called a, b and c, and the angles between them, called α (between b and c),... | 1 | Crystallography |
RingGUI allows for an automated processing of ring diffraction images of polycrystalline or powder samples. It can be used to identify the diffraction rings, quantify the interplanar distances and thus characterize or identify the sample material. With known material, it can assist in microscope calibration. The input ... | 1 | Crystallography |
An amperostat delivers a constant current of about 6—8 mA to the generator electrodes for the titration of the solution, and a digital timer is started. A second pair of silver electrodes are used as a detector to measure the conductance of the solution. The same constant current is known to titrate a given number of ... | 0 | Chromatography + Titration + pH indicators |
Each of the groups in this section has two cell structure diagrams, which are to be interpreted as follows (it is the shape that is significant, not the colour):
On the right-hand side diagrams, different equivalence classes of symmetry elements are colored (and rotated) differently.
The brown or yellow area indicates ... | 1 | Crystallography |
In crystallography, the transition temperature is the temperature at which a material changes from one crystal state (allotrope) to another. More formally, it is the temperature at which two crystalline forms of a substance can co-exist in equilibrium. For example, when rhombic sulfur is heated above 95.6 °C, it change... | 1 | Crystallography |
In its earliest form, liquid chromatography was used to separate the pigments of chlorophyll by a Russian botanist. Decades later, other chemists used the procedure for the study of carotins. Liquid chromatography was then used for the isolation of small molecules and organic compounds like amino acids, and most recent... | 0 | Chromatography + Titration + pH indicators |
The following is an example of the algorithm for determining the axis/angle representation of misorientation between two texture components given as Euler angles:
:Copper [90,35,45]
:S3 [59,37,63]
The first step is converting the Euler angle representation, to an orientation matrix by:
where and represent and of ... | 1 | Crystallography |
The centrifugal partition chromatograph instrument is constituted with a unique rotor which contains the column. This rotor rotates on its central axis (while HSCCC column rotates on its planetary axis and simultaneously rotates eccentrically about another solar axis). With less vibrations and noise, the CPC offers a t... | 0 | Chromatography + Titration + pH indicators |
Because gas molecules diffract electrons and affect the quality of the electron gun, RHEED experiments are performed under vacuum. The RHEED system must operate at a pressure low enough to prevent significant scattering of the electron beams by gas molecules in the chamber. At electron energies of 10keV, a chamber pres... | 1 | Crystallography |
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