Effect of packing density

LM Gregoret, FE Cohen. Effect of packing density on chain conformation. J Mol Biol 219 109-122, 1991. 

Figure 11. Effect of packing density on ligand chain length of surfactant molecules for 3 nm diameter FePt spheres, cylinders and cubes. Current state-of-the-art spherical 3nm diameter particles use / = lnm oleic acid surfactant molecules and have a packing fraction of only p — 19%. Cubic or cylindrical structures with shorter chains are needed to increase p to acceptable levels.

Rate of Solubility—The rath of solubility of small particles depends on a great number of variables. Eq (12-2) takes into account free surface energy (a) and particle surface (1 /d). These are purely surface considerations, and are scarcely complete in themselves. The shape of the surface and its physical state must also be specified, that is, its relative freedom from contamination which might influence the speed of reaction. The effect of packing density and the extent of agitation imparted to the particles are also important, particularly with regard to exposure of fresh surfaces and formation of possible gas pockets. The liquid and liquid-solid phases jointly are additional important considerations. The volume of the liquid, its temperature, and the amount of dissolved solid already in solution must enter into all calculations. Nor can we ignore the chemical nature of the substances involved in the... 

A) Effect of packing density on the TG curve of powdered PM MA. Solid line, densely packed dashed line, loosely packed. 

The PETN Detonation Pressure, P (also called the CJ Pressure), is shown as a function of packing density in Table 7 and in Fig 4. Note that the measured P values in Fig 4 lie quite close to the theoretical curve developed by Lee Homig (Ref 72), which is based on a Wilkin s type equation of state (see Vol 4, D294-L) with a Grueneisen ratio, r, for the detonation products, that is solely a function of specific volume. Shea et al obtained an effective T = 8.077 p-12.288 (Ref 74)... 

In order to fit our structure model to the experimental data, we have to vary the model parameters packing density and cylinder length and examine the effects on the RDDF of our model via the structure factors S and F. One can easily see that an increase of packing density causes the intermolecular distance correlation range to increase because mobility and free volume are reduced. In other words one can calculate a realistic value of packing density (Le. cylinders per volume) from the experimental RDDF (Fig. 18). 

Another important microstructure in IC manufacturing process is shallow trench isolation (STI) that allows the effective separation of active devices and increase of packing densities. Figure 1.23 shows a schematic of an STI structure before and after polishing [51]. It is important for the dishing of the oxide in the trench and the nitride loss to be as low as possible. 

X 10 kg mol , and a smaller influence of crosslinks, Ap /An 10 kg mol . In fact, one can reasonably assume that all the intermolecular attractive forces participate in the increase of packing density. The effect of these forces can be introduced in structure-property relationships through the concept of cohesive energy density (Sec. 10.2.2). 

The effect of packing of sorbed molecules may be important. The volume of sorbed molecules alone will underestimate the pore volume simply due to the manner in which the sorbed molecules pack in the condensed phase. Unlike a bulk liquid phase in which free fluctuations produce a single phase density, the condensed phase in a micropore is constrained to few configurations leading to many possible densities. The particular density of the sorbed phase will depend on how the phase was assembled during micropore filling. These details of sorption are of no consequence for conventional analysis of meso and macropore sorption. 

Figure A3.6.13. Density dependence of die photolytic cage effect of iodine in compressed liquid n-pentane (circles), n-hexane (triangles), and n-heptane (squares) [38], The solid curves represent calculations using the diffusion model [37], the dotted and dashed curves are from static caging models using Camahan-Starling packing fractions and calculated radial distribution fiinctions, respectively [38],...

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