Core Diameter Dependence

Ishii and Murakami (1991) evaluated the CFB scaling relationships of Horio et al. (1989) using two cold CFB models. Solids flux, pressure drop, and optical probe measurements were used to measure a large number of hydrodynamic parameters to serve as the basis for the comparison. Fair to good similarity was obtained between the beds. Dependent hydrodynamic parameters such as the pressure drop and pressure fluctuation characteristics, cluster length and voidage, and the core diameter were compared between the two beds. The gas-to-solid density ratio was not varied between the beds. As seen in Table 7, the dimensionless solids flux decreased as the superficial velocity was increased because the solids flux was held constant. 

Figure 9. Sectorial S-fibre structure Figure 10. Spectral dependence of the attenuation of (microphoto), core diameter 30 pm. the s-fihre and PCS fibre in solution of methylene...

Synthesis of novel materials with desired and tunable physical and chemical properties continues to draw wide interest. Nanomaterials with a variety of shapes and sizes have been synthesized as they offer numerous possibilities to study size and shape-dependent variations of electronic, optical, and chemical properties. Nanomaterials of a particular element show drastic differences in physical and chemical properties when compared with the bulk state. For example, bulk gold, a metal that is insoluble in water can be made dispersible when it is in the nanoparticle form. There are drastic changes in the optical properties as well. Bulk gold appears yellow in color, but when it is in the nanoparticle form with an average core diameter of 16 nm, it appears wine red. Likewise, the chemistry of gold, such as catalysis, also shows a drastic change when the constituent units are in the nanometer range. 

Synthesis of oil soluble micellar calcium thiophosphate was performed in a one-step process involving the reaction of calcium oxide, tetraphosphorus decasulfide and water in the presence of an alkylaryl sulfonic acid. This product could be defined as a calcium thiophosphate hard-core surrounded by a calcium alkylarylsulphonate shell in accordance with a reverse micelle type association in oil. Three micellar products with the same chemical nature core were prepared, each with different core/shell ratio of 0.44, 0.92 and 1.54. Better performances are expected with products of higher core/shell ratios. The antiwear performance of micellar calcium carbonates is directly linked to the size of the mineral CaC03 colloidal particles. At a concentration of 2 % micellar cores, no antiwear effect is observed whatever the micellar size. At an intermediate concentration of 4 % of micellar cores, the wear scar diameter is clearly dependent on the micellar size, slipping from 1.70 mm to 1.10 mm, then to 0.79 mm when the core diameter moves from 4.37 nm to 6.07 nm, then to 6.78 nm. Size dependence is increased at a concentration of 5 % in colloidal cores. This clearly confirms the size dependence of the micellar cores on their antiwear performance (Delfort et al.,... 

For liquids, there are several ways to apply the principle of correct sampling across the vertical dimension. A tool that uses the same idea as the thief is the coliwasa (Composite Liquid WAste SAmpler), shown in Figure 3.9. They come in various lengths and diameters, depending on the depth and size of the container lot. This hollow column is lowered slowly through the liquid until the desired depth is reached. Then the top and bottom are plugged to retain a core. 

Some of the characteristics of the nonheme iron cores of ferritins and hacfers are given in Table II. As can be seen there is a wide variation in properties, though these do not seem to depend solely on overall core size. The mean core diameters measured by electron microscopy for human ferritin (84) and P. aeruginosa hacfer (100) were found to he 70-75 and 60-65 A, respectively, with, in both cases, a distribution of sizes between 55 and 80 or 85 A. The maximum core attainable for human or horse ferritin corresponds to 4500 atoms of Fe per molecule (49), or —33% of the mass of the fully loaded protein. The bacfer core contains less iron and thus is considerably less densely packed. 

The way in which the nanocrystals organize themselves depends critically on the core diameter, the nature of the ligand, substrate and even the dispersive medium used [101]. Thiolized metal nanocrystals readily arrange into two-dimensional arrays on removal of the solvent [29]. Using suitable methods, they can also be put into one-dimensional organization in the form of strings or assembled in a stepwise fashion in a three-dimensional superlattice (see Figure 4.8). 

Fig. 14. Extinction spectra in different media (air, water and water-glycerol mixtures) for sintered opals made of Au Si02 particles with 15 nm core diameter and 225 nm total diameter. The corresponding refractive indices are indicated. The extinction spectrum consists of a surface plasmon mode from embedded gold particles and a weaker Bragg peak. The position of both modes is dependent upon solvent refractive index and (core and shell) particle volume fractions...

For a hard-core diameter d, if (12) is chosen to include the hard core, so that (12)= oo for rthermodynamic state—without quantitatively effecting the value of any exact expressions for h 2), c(12), or e in which > (12) appears. But in the approximate evaluation of such expressions, one must expect that some choices of v(12) ior rbetter approximations than others, and this turns out to be the case, as we shall see. Even for <>(12) that do not have hard cores, it proves useful and natural to exploit our freedom of choice of w(12) for small r. [It is just that without the core, different choices of w(12) now dictate corresponding differences in q r) for a fixed <>(12).] Because only the A and D projections of correlation functions appear in our various representations of e, only the choice of the A and D projections of (12) are of primary dielectric importance in our model. 

As usually formulated, both the LOGA and the MSA are defined only for systems with hard-sphere reference potentials. They can be immediately extended, however, by using one of several perturbation or variational schemes available to relate soft-core reference potentials g(r) to hard-core potentials with state-dependent core diameters. [Of these the... 

Figure la shows that the maximal extinction increases with increasing adsorbed polymer shell thickness and shell refractive index. All curves have a maximum for gold core diameters 60-80 nm. This maximum is closely related to the optimizatiou problems discussed in Refs. [12, 17]. For small particles, the shift of extinction plasmon resonance can be described by a universal dependence [12, 51]. In the first approximatiorr, the optical properties of bioconjugates are well explained by a simple two-layer electrostatic model (previous analysis [43] contairrs some inacctrracies, see Ref [12]). We shall consider the extinction spectra only. For small conjugates, the extinction is determined by the absorption efficiency... 

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