Mean crystal length

Increasing the crystalline melting point and mean crystal length in the molecular chain direction was found to substantially increase the tensile strength of the fiber. Polyvinylidene fluoride resin had to have... 

The magnetic hyperfine field (Bhf) decreases as structural Al increases. This is to be expected because the diamagnetic Al does not contribute to the magnetic field. Since, however, Bhf (T) is also reduced as the crystal size decreases (even at 4 K), both Al substitution and crystal size (here represented by mean coherence length perpendicular to (111), MCLm, in nm) must be combined to account for the variation of Bhf satisfactorily, (Schwertmann Murad, 1983) i.e. 

The crystal size of soil Fe oxides usually ranges from a few to several hundred nm. A survey of 256 goethites, 101 hematites and 72 lepidocrocites from soils around the world showed maxima in the mean coherent length (MCL) perpendicular to (101), of 15-20 nm for goethite and ca. 40 nm perpedicular to (110), for hematite (Fig. 16.10). These values have been deduced from XRD line broadening using the Scherrer for-... 

Form. Spread a thin layer of wet sample over a 0.5 square inch area of the central surface of a 1-in by 3-in glass microscope slide, in such a manner that the individual crysts are discernible. Measure the crystal length by means of a micrometer eye-piece using a magnification of ca 40... 

The last column is of the summation Wj/Lj at corresponding values of crystal length L. The volumetric shape factor is av =0.866, the density is 1.5g/mL, and the mean residence time was 2.0 hr. The linear growth rate G and the mideation rate B° will be found. 

The mean diffusion length of the minorities is drastically dependent on crystal imperfections. It may also be dependent on surface orientation, if they have an anisotropic mobility. Optical anisotropy is necessary for seeing an influence of crystal orientation on the penetration depth of the light while crystal imperfections will only affect the penetration depth in a range of wave lengths where light absorption in the crystal is very weak. The photocurrents are very small in this case which will not be discussed here. 

Table II summarizes the 23 possible treatment combinations. Run (1) denotes a synthesis with all factors at their lowest level. Product yields, see Table II, and maximum crystal sizes along the (001) axis (Table III) represent mean values from duplicated sets of each trial. The "effect" column lists the impact of a factor, positive or negative, on the response, viz. product yield and crystal length, for the case that the level of this factor is raised from a medium to a high level. Calculation procedures have been described in the literature (10).

When the salt of PMAA is formed the rigidity of polymer chain is increased a little that leads to little increase of values of mean-square length of monomer unit and distance between polymer chain ends. The result obtained under addition to polymer salt solvent in methanol (40 vol. % of water, at large content of water the solution is not vitrificated, but is crystallized) represents special interest at that the macromolecule in solid state keeps conformation of Gauss ball (Figure 2), however, as we should expect, rigidity (parameter a) and sizes of ball are increased (Table 1). 

Between different classes of molecules, the mean bond lengths for various donor-acceptor combinations do not always agree even when there are reasonably good statistics. This is because of differences in the average crystal field effect for molecules of different shape and functional groups, as discussed in Part IB,... 

The structure of tetrakis(l-methylcyclopropyl)ethene (40) has been determined at -100°C by XD The highly strained molecule possesses a nearly perfect (noncrystallo-graphic) symmetry in the triclinic P crystal (Figure 8), with the most twisted double bond known at that date. The mean torsional angle about the double bond is 19.7°. Selected mean bond lengths (A) and bond angles (deg) are listed here -... 

The moments have physical meaning. The zeroth order moment (iq is the total number of particles per unit volume (or mass, depending on the basis). The first-order moment fii is the total length of the particles per unit volume, with the particles lined up along the characteristic length. The second-order moment is proportional to the total surface area, and the third-order moment is proportional to the total volume. Many physical characteristics of the particles such as the number-mean crystal size, weight-mean crystal size, the variance of the distribution function, and the coefficient of variation also can be represented in terms of the lower order moments of the distribution. 

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