Crystal defined

A common feature of anorthite crystals in Allende Type B inclusions is large variations (up to a factor of -v 5) in Mg content on a scale of 10 to 50 pm. (Mg variability and its correlation with Na content and cathodoluminescence color are discussed extensively in [12].) Guided by cathodoluminescence micrographs, we used the microscopic spatial resolution of the ion-probe to measure the Mg isotopic composition at several points with distinct 27Al/24Mg ratios within individual crystals from TS-21 and TS-23. Data from each individual crystal define an... 

Solv=MeOH, EtOH and PrOH), and l,4-bis(4-pyridyl-butadiyne) (bpb, n= 0.5, Solv=MeOH). Like the btr derivative, compressed [FeN6] pseudo-octahedral sites define the knots of the square- or rhombus-shaped windows, which constitute the layered grid structure of the three compounds. Stacking of these layers in the crystal defines their most important structural differences, which are determined by the ligand size and crystal packing efficiency. In principle, the 2D grids are organised in a fashion similar to that described for the [Fe(btr)2(NCX)2]-H20 system the parallel layers are alternated so that the iron atoms of one layer lie vertically above and below the centres of the squares formed by the iron atoms of the adjacent layers. 

The molecular boundary for the formamide crystal, defined according to Eq. 

KcsA is a potassium channel protein from Streptomyces lividans that assembles as a tetramer.68 An X-ray diffraction study of a crystal defined the transmembrane and some extracellular portions of the structure but no structural information could be obtained for cytoplasmic domains. Since the protein assembles as a tetramer, when one spin label is present on each subunit, it is difficult to interpret the dipolar interactions because of the presence of adjacent... 

Monochromator crystals are monocrystalline blocks or multilayer structures in which the selective reflection of X-rays is determined by the periodic arrangement of the constituent atoms (inter-planar distance d). An X-ray will only be reflected (and thus detected), for a given position of the crystal (defined by the angle of incidence 0) if its wavelength A. meets the Bragg criteria ... 

The nearest neighbours of an atom in a molecule, complex ion, or crystal, define a polyhedral coordination group, the number of vertices of which is the coordination number (c.n.) of the atom. It is convenient to describe the structures of many essentially ionic crystals in terms of the coordination groups around the cations. It is to be expected that coordination polyhedra with triangular faces will be prominent because these are the most compact arrangements of atoms in a 60... 

Because an analyser crystal defines the diffractometer scattering angle 26 by its own true orientation with respect to the incident beam, several aberrations, which can affect diffractometers equipped with a simple receiving slit before the detector or a PSD, do not occur. (In reality for the latter diffractometers, the 26 scale is inferred from the position of the slit or the element of the PSD.) Thus, 26... 

Magnetic Structure Factor. From Equation (43) we can develop in a compact form the magnetic structure factor of the crystal defined as ... 

Frenkel and Schottky point defects in crystals defined. The effects they have on the density of a crystal... 

Some useful relationships for quiescent crystallization, defined as crystallization in the absence of any applied deformation, will be summarized in this section. These relationships cannot generally be used in a truly predictive manner at this time. Their practical utility is limited mainly to providing a framework within which to analyze and correlate data. The reader interested in very extensive further details, including many literature references and examples using polypropylene and polyethylene terephthalate), is referred to our review article [64],... 

A beam of radiation will only be diffracted when it impinges upon a set of planes in a crystal, defined by the Miller indices (hkl), if the geometry of the situation fulfils quite specific conditions, defined by Bragg s law ... 

The optical gain resulting from the stimulated emission process can be determined by evaluating the signal enhancement (SE) when the probe beam passes through the crystal, defined as follows... 

The Miller indices, (h kl), of plane in a lattice or a crystal define the positions where the plane cuts the unit cell edges, oq, and cq. A set of parallel planes has the same Miller indices. Negative intersections are represented by bar h, (h), bar k, (k), or bar l(J). 

Examining and describing crystals Defining crystal structures Expanding crystals into crystal systems Studying characteristics of crystals Recognizing how crystal defects are useful... 

Figure 6.20 Geometry of the slip plane and slip direction in a single crystal, defined with respect to a uniaxial applied stress.

A more common way of building an intensity modulator uses two LiNbOj crystals in tandem. The crystals are arranged in a set-up similar to that in an amplitude modulator and are positioned so that the external field is applied parallel to the optical axis and the light beam travels perpendicular to it. However, the crystals are positioned so that the x- and y-axes are arranged at an angle of 45° to each other. The entry beam is accurately polarised vertically so that its electric vector bisects the x-andy-directions (Figure 9.12). This will split into an ordinary and extraordinary ray, each with polarisation normal to the other as it enters the first crystal. The second crystal is oriented so that the ordinary and extraordinary rays in the first crystal, defined by their relative polarisation, swap and become the extraordinary and ordinary rays in the second crystal. In this way, the ordinary and extraordinary beams travel identical optical paths. On emerging, the ordinary and extraordinary waves will have a phase difference due to the imposed values of the external electric field and will be linearly polarised perpendicular to one another. 

A simple analysis of an irreversible first-order transition is the cold crystallization, defined in Sect 3.5.5. For polymers, crystallization on heating from the glassy state may be so far from equilibrium that the temperature modulation will have little effect on its rate, as seen in Fig. 4.122. The modeling of the measurement of heat capacity in the presence of large, irreversible heat flows in Fig. 4.102, and irreversible melting in Figs. 3.89 and 4.123, document this capability of TMDSC to separate irreversible and reversible effects. Little needs to be added to this important application. 

Line or crystallographic direction through the center of a crystal that is parallel to the intersection edges of the crystal defining the crystal zone. 

The dependence of the solubility of a solid on temperature varies considerably, as shown in Figure 9.9. For example, the solubility of KNO3, for example, increases sharply with temperature, while the solubilities of NaBr and NaCl change very little. This wide variation makes it possible to obtain pure substances from mixtures through the process of fractional crystallization, defined as the separation of a mixture of substances into pure components on the basis of their differing solubilities. 

The initial research on electro-optic phenomena in side-chain polymer liquid crystals concentrated on systems that exhibited nematic phases so that a ready comparison could be made with low molar mass mesogens. Such measurements have established that electro-optic devices are feasible and have allowed elastic constants to be deduced from applications of the continuum theory. This theory, originally derived for low molar mass nematic liquid crystals, defines a relationship for the free energy density F in terms of the elastic constants (/ ) and the director n such that ... 

Differences between PET-CT systems apply to the number of detector rows with which the CT component is equipped. Currently, up to 64 detector rows have been integrated in PET-CT. For the PET component, different detector materials have been available. The three most common detector materials are bismuth ger-manate (BGO), lutetium oxyorthosilicate (LSO), and gadolinium oxyorthosilicate (GSO). All available PET-GT systems are equipped with a full-ring PET detector (360° coverage). The size of each detector crystal defines the spatial resolution of the tomograph, which may range from 2 to 5 mm. 

Equation (6.26) yields the melting point depression in terms of fundamental parameters. The quantity ct, may be interpreted in terms of the fold structure. For the actual crystallization, chains are added from the melt or solution to the surface of the crystal defined by the area x(, and T° represents the large crystal limit. 

Ki denotes the lowest order anisotropy constant for cubic crystals defined in section 4 A denotes any of the lowest order magnetostriction constants As, Aioo or A i. /,+i/2 is a reduced hyperbolic Bessel function of order /, and i " [mR]... 

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