Particular crystal structure

There is no evidence that any particular crystal structure is more readily corroded than any other. For example, the difference in the corrosion behaviour of austenitic and ferritic stainless steels is, of course, due to compositional rather than structural differences. 

Members of the different SERM families bind to the ligand-binding domain (LBD) of the ER, whose particular crystal structure has been revealed for estradiol and for raloxifene (Brzozowski et al. 1997). Once inserted into the binding cavity, estradiol makes direct hydrogen bonds bewteen its A-ring and... 

The discrepancy in numbers between natural and synthetic varieties is an expression of the usefulness of zeolitic materials in industry, a reflection of their unique physicochemical properties. The crystal chemistry of these aluminosilicates provides selective absorbtion and exchange of a remarkably wide range of molecules. Some zeolites have been called molecular sieves. This property is exploited in the purification and separation of various chemicals, such as in obtaining gasoline from crude petroleum, pollution control, or radioactive waste disposal (Mumpton, 1978). The synthesis of zeolites with a particular crystal structure, and thus specific absorbtion characteristics, has become very competitive (Fox, 1985). Small, often barely detectable, changes in composition and structure are now covered by patents. A brief review of the crystal chemistry of this mineral group illustrates their potential and introduces those that occur as fibers. 

This surface is therefore the (111) surface. This surface is an important one because it has the highest possible density of atoms in the surface layer of any possible Miller index surface of an fee material. Surfaces with the highest surface atom densities for a particular crystal structure are typically the most stable, and thus they play an important role in real crystals at equilibrium. This qualitative argument indicates that on a real polycrystal of Cu, the Cu(l 11) surface should represent a significant fraction of the crystal s surface total area. 

Beside dislocation density, dislocation orientation is the primary factor in determining the critical shear stress required for plastic deformation. Dislocations do not move with the same degree of ease in all crystallographic directions or in all crystallographic planes. There is usually a preferred direction for slip dislocation movement. The combination of slip direction and slip plane is called the slip system, and it depends on the crystal structure of the metal. The slip plane is usually that plane having the most dense atomic packing (cf. Section 1.1.1.2). In face-centered cubic structures, this plane is the (111) plane, and the slip direction is the [110] direction. Each slip plane may contain more than one possible slip direction, so several slip systems may exist for a particular crystal structure. Eor FCC, there are a total of 12 possible slip systems four different (111) planes and three independent [110] directions for each plane. The... 

An additional factor, /, has been included to account for the number of equivalent sites to which an ion may transfer in a particular crystal structure for example / = 4 for an ion vacancy in the cubic crystal structure. 

The lattice energy based on the Born model of a crystal is still frequently used in simulations [14]. Applications include defect formation and migration in ionic solids [44,45],phase transitions [46,47] and, in particular, crystal structure prediction whether in a systematic way [38] or from a SA or GA approach [ 1,48]. For modelling closest-packed ionic structures with interatomic force fields, typically only the total lattice energy (per unit cell) created by the two body potential,... 

This so-called localization effect depends on the crystal structure of the specimen (which determines the magnitude of the channeling) and to a lesser extent on the chemical composition. Thus, determination of site-occupancy is not fully quantitative, as previously assumed, and correct site-occupancies can be obtained only by experimentally determining correction factors for the particular crystal structure being investigated. 

When the unit cell is found, it can be used to search multiple databases in addition to the ICDD s Powder Diffraction File. A positive search result usually confirms indexing, while a negative outcome does not necessarily mean that the indexing is wrong - a particular crystal structure may be novel and/or not yet included in a database. 

Dislocations in Particular Structures by S. Amelinckx from the 1979 volume of Dislocations in Solids is an incredible achievement in which Amelinckx considers the peculiarities of dislocations that attend particular crystal structures. A truly incredible article ... 

The STR may be used to calculate the canonical structure constants defined by (6.7-9) or (8.23,24). In a typical application the programme is executed once for a given crystal structure. It produces and stores on disk or tape a set of structure-constant matrices distributed on a suitable grid in the irreducible wedge of the Brillouin zone. Whenever that particular crystal structure is encountered, the structure constant matrices may be retrieved and used to set up the LMTO eigenvalue problem which, in turn, leads to the energy bands of the material considered. 

It may be supposed that the particular crystal structure of an intermetallic reflects the character and strength of bonding in a sensible way, and thus the crystal structure would be a good criterion for phase classification. However, this does not mean that intermetallics with the same crystal structure are similar with respect to bonding and properties since, e.g. the B2 structure is common to the intermetallic Ni Al and to the purely ionic salt CsCl, and in the case of the transition-metal disilicides with a... 

Outlying observations will occur in any study of this type. These are observations which differ very significantly from the mean value for the distribution. Outliers can arise for a number of reasons, but principally (i) due to some (unknown) systematic error(s) in a particular crystal structure analysis, or (ii) due to some very specific chemical effect(s) within a particular fragment. In this work, we have defined outliers as being more than from the initial mean value. In these (very few) cases, the mean is recomputed for inclusion in the final tables with any outliers excluded. 

Grain structure is the arrangement of grains in a metal, with a grain having a particular crystal structure. 

The spectmm is influenced by the particular crystal structure of the sample s top few atomic layers, which may not be completely representative of the bulk material. 

The low energies of the electrons involved means that the technique can be vulnerable to stray magnetic fields and magnetic shielding may be required. Spectra can be influenced by the particular crystal structure of the sample s top few atomic layers, which may not be completely representative of the bulk material. IPES is generally not suitable for insulating materials. 

JT is unique for a particular crystal structure and is the same for NaCl and MgO. 

Secondary bonds are so called because the compound involved invariably also has ionic or covalent bonding. Secondary bonds are generally much weaker than primary bonds, although they can be critical in determining both the existence of a particular crystal structure and the properties of a material. 

The present paper focuses on the application of the electron gas model to the calculation of mineral properties, particularly crystal structures, cohesive energies, electron densities, compressibilities, and pressure-induced phase transitions. The effects of partial covalent bonding, or equivalently the non-spherical distortions of the ions, on these properties are addressed. 

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