A unified survey of existing statistical theories of heterogeneous materials is presented. The macroscopic behavior of heterogeneous materials is treated as a certain stochastic process with space parameter and discussed from the standpoint of statistical continuum theories. Attention is focused on the problem of prediction of effective physical constants of heterogeneous media in terms of physical constants and geometry of constituents. Besides classical theories of dilute suspensions, perturbation procedures and variational approaches for statistically homogeneous random materials of arbitrary phase geometry are reviewed.
Intensity fluctuation properties of focused and collimated light beams propagated through a random medium have been experimentally studied by investigating their fluctuation indices, power spectral densities, cross--correlation functions and probability distributions.
The principle for using a Wien filter as a mass spectrometer was examined in order to use the filter as a detector or a mass selector in beam experiments. The Wien filter is a kind of mass spectrometer of the trochoid type and shows maximum resolution when the exit slit is placed at the first order focusing point on the axis of the injection of ions. A small Wien filter (40mm wide×45mm thick×102mm long) with a permanent magnet was constructed for alkali ion separation. This filter with the slit widths 1mm showed maximum resolution of about 25, which is comparable to the calculated value 32 for ideal resolution, while the ion transmission was found to be 10-3.
Image forming methods are proposed to obtain large demagnification factors by a three element quadrupole lens system. The inlet element of the lens system with axial length 2 L acts as a quadrupole singlet. Middle and outlet elements, both of equal length L, act as a quadrupole doublet. Their paraxial focusing characteristics are calculated based on a rectangular field model. A virtual image is formed by the diverging singlet within the singlet system and a real image of the virtual one can be formed outside of the lens system by the converging doublet. Magnification factors of the final image are about ten times smaller for the same object and image distances than those obtained by a symmetrical triplet having an equal total lens length to the above system. The accuracy is discussed, compared with those based on a modified bell-shaped model. The parameters of the model are determined from the potential distribution measured by an electrolytic tank method.
Experiments concerning bleaching techniques are carried out with the object of obtaining phase holograms of high quality. Phase gratings are made on the photographic plates (Kodak 649 F) through several kinds of bleaching processes. The highest diffraction efficiency of 70% (at 6328 A) is obtained through the process using chromium intensifier as the bleaching agent and thioglycollic acid as the stabilizer. The process using potassium ferricyanide as the bleaching agent gives a diffraction efficiency of only 50% but shows the highest stability. Prehardening the emulsion before these processes improves (1) the correlation between the diffraction efficiency and the photographic density (before bleaching), and (2) the spatial frequency characteristics. The latter process with prehardening is applied for making a fourier-transformed hologram memory whose diffraction efficiency, signal to noise ratio and signal nonuniformity are 8%, 40 and 2. 3, respectively.
For a reliable quantitative electron probe microanalysis it is absolutely necessary to make some correction calculations, namely, correction for absorption, atomic number and fluorescence. However the correction calculation procedure for a given material, especially a multi-component system is so complicated that it requires much laborious work. This paper presents a method for approximate calculation of each element in multi-com-ponent systems from the measured intensities of their characteristic X-ray radiations. The results clearly show that the proposed method is very useful for obtaining a quick and accurate determination of the constituent elements in the multi-component systems.
The crystal structure of semiconductors of (Bil-xSbx)2(Te1-ySey)3 system has been found to be either hexagonal or orthorhombic for all compositions from X-ray analysis. Atomic parameters (u, v) of crystal structure and bond lengths (dl, d2, d3) in the whole range of the hexagonal structure are determined by X-ray powder pattern techniques. In this region atomic parameters, u and v are 0.400 and 0.209, respectively. Bond lengths can be expressed in terms of the composition parameters x, y in the following equations; dl(M-X1)=3.25-(0.054x+0.184y) (Å) d2(M-X2)=3.08-(0.057x+0.176y) (Å) d3(X2-X2)=3.62-(0.048x+0.198y) (Å) Relations between the crystalographic data and physical properties are discussed.