A review of the studies of metals and alloys by the Mössbauer spectroscopy is given with some typical examples mainly performed in the author's laboratory. In the first part are introduced the fundamental concepts and principles of the Mössbauer effect measurement, the important Mössbauer parameters such as the isomer shift, electric quadrupole splitting, internal magnetic field, line shape, etc., and the methods of qualitative and quantitative spectral analyses. In the second part of the article, applications of the Mössbauer spectroscopy to the study of order-disorder phenomena, determination of solid solubility, precipitation and phase separation, steel martensite, invar problem, hydrogen in metals, and amorphous alloys are described and discussed.
Discharge products were studied with the use of an infrared spectrometer in a cylindrical discharge tube. The results obtained are as follows. The main constituents of the gases produced by a discharge in air are N2O, NO2, HNO3, and O3. Among them, N2O is stable and its concentration does not decrease for a long period of time after the discharge. On the other hand, HNO3 and NO2 are unstable and decompose immediately after the discharge. Both HNO3 and NO2 are produced periodically at a humidity higher than 3×1016/cm3 in air. In particular, the concentration of NO2 increases suddenly when HNO3 decomposes. At low pressures, a small amount of O3 is generated, whose concentration increases with increasing pressure. On the contrary, HNO3 does not exhibit a periodic generation and its concentration is low at high pressures.
Attempts were made to prepare n-type ZnTe with Al diffusion in ZnTe single crystals which were sufficiently annealed in liquid Zn to decrease Zn vacancies. The fact that ZnTe: Al showed n-type conduction was ascertained by the hot probe method, the Hall effect and electrical properties of ZnTe diode. The diffusion depth of Al atom was determined by potential distribution measurements of the reverse bias ZnTe junction. The activation energy of the diffusion coefficient was 1.2 eV. The electrical conduction mechanism of ZnTe junction was dominated by the generationrecombination process in the space charge region. C-V characteristics indicated that this diode was of a graded type junction. This diode showed also electroluminescence under a forward bias which was attributable to an injection mechanism. The impurity levels associated Al atom were shown to be 0. 02 eV and 0. 2 eV by the photoconductivity of ZnTe: Al single crystals.
The behavior of the Z pinch in a low pressure Ar gas (3_??_100 mTorr) was experimentally studied. The behavior of a current layer under low pressure where a current layer was not formed into shell type was observed by an image converter camera, and the current density was obtained by a magnetic probe. When a current layer is formed into columnar type, the current density increases uniformly at first, and then concentrates around the tube axis. This behavior of a current layer is different from that assumed by the snowplow model. At the imploding phase a luminous region is recognized around the current layer which is imploding towards the tube axis, and this region is explained by the characteristic length which is obtained by the comparison between the term J×B and the term _??_p.
A slightly different color from that of the painted film is sometimes observed after wax polishing. The color difference is more remarkable with deeper colors. In order to study this phenomenon, the chromaticity coordinates of color were measured and compared with those calculated from interference theory. A model was proposed to describe the environment where the color change is observed. Formulas including the optical characteristics of the environment were derived and numerical calculations were performed for elucidation of pronounced color change for deeper colors. It is concluded that the color change is mainly due to an interference effect. The deep color effect can be explained by addition of different color lights: specular reflected light (corresponding to the color of wax coating) and diffuse reflected light (corresponding to pigment color).
We have evaluated the stability of recently developed anthraquinone dichroic (pleochroic) dyes for use in guest-host liquid-crystal color display, comparing it to that of azo and merocyanine dichroic dyes used coventionally for color display. The evaluation has shown that the anthraquinone dyes are extremely stable to light, whether or not an electric field is applied, although their dichroic ratio is relatively smaller than that of the other dyes. This may meet the photo-stability requirement for dichroic dyes from the viewpoint of practical application of the guest-host color display.
The state-of-art of “incoherent-to-coherent” optical image conversion (ITC) devices developed for coherent optical information processing is reviewed. The operating principles of such devices are briefly explained, followed by a table of detailed specifications. Several examples of real-time optical information processing such as holography, correlation operation, pattern recognition and image processing are also described. The present ITC devices are expected to have the resolution higher than 20 line-pairs/mm for the MTF value of 50%. The future devices will be developed in combination with digital computer processing.
This article surveys non-destructive measurement of three-dimensional refractive index distribution, in which we calculate the distribution from complex amplitude of the light wave transmitted through or scattered by the medium to be measured. Formulas for the calculation are explained as the solution of the inverse problem for the scalar wave equation. Some approximate inverse formulas are described. They include approximations of geometrical optics, straight path, the Born and the Rytov. As their applications, measurements of distributions of air density in the aerodynamic experiments, electron density in plasmas and refractive index in optical fibers are reviewed. Brief account is also made on similar measurements with waves other than light wave. Design of a graded index lens is described as another application.
The problems for the mass spectrometry of organic substances with M>1000 are discussed and several examples of mass spectra of high molecular weight are shown. Using a second order double focusing mass spectrometer (rm=50cm) and an FD ion source with silicon emitters, mass spectrum of polystyrene up to M=11000 was obtained. The FD mass spectrum of a polymer sample indicates the distribution of the degree of polymerization. These mass lines can be used as standards of mass calibration for heavy mass region. Quasi molecular ions (M+H)+ appear normally in the FD mass spectra of peptides. A new method for the determination of amino acid sequence of a peptide is described. A new type of mass spectrometer using E×B crossed field is useful for the mass analysis of very heavy molecule.
Plasma-wall interactions play an important role in most of the magnetically-confined fusion devices in the respect that the particle as well as energy balance are seriously affected. Various processes occurring in plasma-wall interactions are described and the present-day's knowledges of each process are reviewed.