Cell, unit number density

Phase CAS Registry Number Formula Crystalsystem Spac egro up Molecules perunit cell Unit a cell length, nm b c Density, g/cm ... 

The cell concentration is usually expressed by the cell number density C (the number of cells per unit volume of medium), or by the cell mass concentration... 

Density. To determine the number of complex moieties per unit cell, n, the density of the single crystals must be known since... 

Cx Cell concentration, dry cell weight per unit volume CN Cell number density, number of cells per unit volume p Cell density, wet cell weight per unit volume of cell mass Accordingly, the growth rate can be defined in several different ways, such as ... 

The density can be used to calculate a if we count the number of ions of each type per unit cell. The number of assigned Cl- ions per unit cell is one-eighth of the number of corner Cl- ions, or (8) = 1. 

We have seen that the shape and size of the unit cell of a crystalline substance may be determined from the positions of the reflected beams. The number of atoms in the cell follows directly from, the size of the cell and the density of the substance for information concerning the positions of atoms, however, it is necessary to rely almost entirely on the relative intensities of the beams. There are a number of photoelectric devices known for measuring the degree of blackness on a clear film or the degree of whiteness on a black film a good measurement of the intensity of beams is obtained by using a movable Geiger counter instead of a film, for the intensity of ionization within the spectrometer chamber is proportional to the number of photons received. Reflections from some planes may be completely absent. 

Salt Melting point Dimensions of unit cell Vol. Meas. density g/cc at 5 °C 0.005 Hydration number (chemical) Hydration number (crystal) Number of formula units per unit cell... 

The object is to partition the time of an individual predator. Let N denote the number of prey caught during a food-search time period of length T. Let x denote the prey density (units are cells/unit volume), s the search rate (units are volume/time), and b the handling time (units are time/prey). One then has N = sx(T-bN). The functional response (the consumption term) for one predator is N/T or, extending over a unit volume. 

Properties of calcium and strontium zeolites apparently are caused by the fact that ions of calcium (strontium) during the process of exchange occupy the screened positions Si and Sn, and the number (density) of cation centers per unit cell decreases (32, 34). 

N is the number density of molecule, and Ng is the number of equivalent sites (in a crystal). They are related by N = Ng/V, where V is the unit cell volume. The angle Sjf expresses the relation between the crystallographic (or laboratory) axis I and molecular a s for a particular constituent of the unit cell. The local field factors fi (ot)., etc., are related to the appropriate laboratory axis and frequency. For disordered materials, Ng=l. 

Figure 2. The SWAP the abclssa Is number of unit cells a, electron density b, force on lattice by electron c, lattice displacement d, Incident phonon e, scattered phonon. (Reproduced with permission from reference 5. Copyright 1985 Nljhoff.)...

The density can be used to compute a if we count the number of ions of each type per unit cell. The number of assigned CP ions per unit cell is one-eighth of the number of corner Cl ions, or (8) = I. The only Cs in the unit cell is the center Cs, so that the assigned number of cesium ions is also I. (This type of assignment of ions or atoms in a compound must always agree with the empirical formula of the compound, as the 1 1 ratio in this problem does.) The assigned mass per unit cell is thus that of I formula unit of CsCI. 

The cell concentration is usually expressed by the cell number density Cn (the number of cells per cubic meter of medium), or by the cell mass concentration Cx (the dry weight, in kg, of cells per cubic meter of medium). For any given size and composition of a cell, the cell mass and the cell number per unit volume of medium should be proportional. Such is the case of balanced growth, which is generally attained under some suitable conditions. The growth rate of cells on a dry mass basis, rx (expressed as kg dry cells m-3h-1), is defined by ... 

Application to the BPTI Crystal. The system to be simulated consisted of the protein atoms of one BPTI molecule (5) and 140 water molecules. The required number of water molecules could be calculated both from the volume of the crystal for which protein-water energy is zero or negative (solvent space) (9) and from unit cell volume and density of protein and water. Protein-water interactions were calculated as in the first part of this article, protein-protein interactions as described elsewhere ( ). Interactions between water molecules were calculated using the ST2 model, introduced by Rahman and Stillinger in a molecular dynamics simulation of liquid water (11). 

Calculated from wet chemical analysis for zeolites shown in Table VII except for zeolite P-C, where the average of wet chemical and microprobe analyses (3) was used. All calculations were normalized to the appropriate number of tetrahedra/unit cell. Unit cell dimensions are in A, and densities in grams/cc at 25°C. 

TC3P crystallizes in the tetragonal FcjP-type structure. The lattice constants of Tc. P are a = 9.568 and c = 4.736 A. Tc-,P proved to be isoslructural with Mn P. CrsP, and NisP and shows a high coordination number for all atoms, which is typical for intermc-tallic compounds and other electron-deficient compounds with high metal content. With Z = 8 formula units in the cell, the calculated density is 10.04 g cm [16]. 

A pattern of intensities that are absent for a given unit cell gives important clues about the space group, the description of the symmetry that applies to that crystalline form. For example, the intensities for the meridional reflections on the first, third, fifth, and higher odd layer lines are absent for the Ply space group. The number of chains can be inferred from the dimensions of the unit cell and the density of the sample. Whether there is true symmetry in the cellulose crystallites has always been controversial, with weak odd-order meridional reflections [199] often appearing, thus failing to meet the strict requirement of absence. These... 

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