Characteristics and analysis of a simple automatic scanning device using an electromagnet are described. For n-m-r studies of broad lines in solids, the spectrometer is easily constructed by the use of a magnet and proved to be very useful. As an example, field dependent n-m-r signals in a paramagnetic solid are shown. Concentration of heavy water from 30 to 85% can be quickly determined with the accuracy of about 5% in error by measuring signal amplitude ratios of D to H at a given frequency.
Loosjes and Vink proposed the pore conduction hypothesis derived from the approximate equality in values of activation energy of conductivity at high temperatures and work function by Richardson plots and also from TV characteristics obtained in their experimental study. Seen from their experimental method, the current in the I-V characteristics is of stationary state value. In the author's experiment, the characteristics are examined for current of d. c. instantaneous value, of stationary state value after the lapse of time, and for a. c. voltages of various frequencies, and also for the case of d. c. and a. c. superimposed voltages. The characteristics are linear for all d. c. instantaneous values and a. c. values, but for d. c. stationary values, the linearity is lost at high voltages. As to the activity, the linearity holds only for its high values. The conduction current of oxide cathodes is found to decay in msec-sec as well as the emission current. The deviation from Ohm's law in d. c. stationary state current at high voltages is due to this decay. This dacay of conduction current can be explained by the pore conduction mechanism. It is understood as due to poisoning of gas released from inner oxide walls to pores of crystal intensities as well as the decay of emission current. Thus, when the decay is taken into consideration, all of the I-V characteristics obtained in this experiment are very well explained. There are two activation energies, one in each of the higher and lower temperature regions. The former is of the pore conduction and the latter is of the bulk crystal. In this case, the values of activation energy of conduction and work function are not always equal which is not in line with the results of Loosjes and Vink. This can, to some extent, be explained by considering the difference in surface activities of outer crystals and inner crystals of oxide cathodes.
Interesting phenomena observed in electro-luminescent patterns by photon irradiation are described and interpreted. 1. In an electroluminescent pattern, two peaks, the main and the secondary, appear in succession. By photon irradiation, the secondary peak is shifted toward the main peak that follows it. Infrared irradiation and high temperature prevent this shift. This led to a conclusion that the phase shift of the secondary peak is caused by electrons in shallow traps. 2. Difference between an electroluminescent pattern and a modulated pattern is mainly due to the difference in distributions of excited centers in phosphor particles. 3. Discussion is made on the possible excitation of luminescent centers by the inverted inner field immediately after the removal of external field.
According to the procedures adopted for preparing the materials and making the crystals grow, single crystals of LiF are apt to include impurities, which bring about remarkable absorptions in near infrared and ultraviolet regions (at 2.8p, 200 mp or shorter wavelength and over the range from 250 mp to 300 my). Paying attention to the purifying method of materials, pure crystals are successfully made by a new type vacuum furnace, and the influence of atmospheric gas on the crystal growth is examined. The crystallization of LiF is carried out by a modified Kyropoulos' method in dry nitrogen gas kept fresh by continued streaming, crystal growth being observed through a glass window of the vacuum furnace. The crystallization by this furnace is so feasible compared with Bridgman-Stockbarger's method that various other materials can be crystallized as well as LiF under respective growth conditions. As for the purification of LiF materials, three preparation methods were adopted and the one that started from lithium chloride and ammonium bifluoride was found most favorable. In crystals made from the purest materials, absorption below 200 my is very much weakened. In vacuum-grown crystals, in general, 2.8 p absorption in the near infrared and the absorption from 250 mp to 300mp are completely eliminated. Brief account of the properties of these absorption bands is given.
Silver bromide single crystals taken from melt are bombarded with electrons of up to 350 eV and deuterons of 2 MeV, and decompositions to silver is examined by means of electron diffraction method. In the case of slow electrons, decomposed silver is found only in shadowed parts near the bombarded part on the surface. But if the specimens are preilluminated, silver is seen decomposed even in bombarded part. Orientation of the silver is mainly parallel; it is the more perfect the farther the part is away from the bombarded part, and just near the bombarded part, Dankov's orientation is recognized together with random orientations. In the case of deuterons, the silver could not be found on the surface, but in the interier down to about 40 micron depth, random orientation of silver is observed, Silver deposited onto silver bromide crystals by evaporation changes in several months to silver of Berry's orientation with forbidden spots in its diffraction patterns, and the crystals are easily sensitized to produce silver. Such experimental results are explained from the statistical viewpoint of energy level scheme (S. Sonoike: J. Appl. Phys. Japan 25, 115 (1956)) by introducing into it space charges and pseudo Fermi levels.
Crystal structure of micro-crystals in rice grains and the effect of moisture upon it are studied by using X-ray powder method. The rice grain is made up of micro-crystals of starch in random orientation as the powdered rice and the moisture enters only into interspaces in the crystal aggregate and therefore the moisture does not constitute the water of crystallization. In some cases, however, a part of the moisture may affect on their crystal structure.
Rapidly varying light intensity is measured by using a photomultiplier tube as a shutter. Since the tube is sensitive to light only while proper pulse voltages are being applied to its dynodes, it acts as an effective shutter. A pulse generator is devised to generate pulses which can be set to any desired delay after the pulsation of light. The delay can be set to 0.2_??_500μ sec with the pulse width of 1_??_1000μ sec. Thus, the light intensity at any required phase of light is made possible to be measured.
In part I, several gas flow equations involving the terms which show the effect of gas molecules on the inner surface of a high vacuum system was described. In this paper the behavior of the two most important vapours in a high vacuum apparatus, water vapour and oil, are discussed with some experimental results. When a vacuum chamber is evacuated, non-adsorbable gases are pumped out easily thus causing the partial pressures of adsorbable gases or vapours to become predominant among the residual gases or vapours. A vacuum chamber, which is exposed to atmospheric air, adsorbs a large amount of water vapour on its inner surface. Desorption of the water vapour is slow even in vacuo; the partial pressure of water vapour is usually most predominant in the pressure region of 10-zmmHg to 10-4mmHg in a so called dynamic vacuum system. Greases and oils are usually the next predominant in high vacuum apparatus. Even the physically adsorped oils and greases are difficult to be removed by simple pumping because of their large heat of desorption. Their vapour pressures are usually ranging from 10-4mmHg to 10-7mmHg, often limiting the ultimate vacuum of a vacuum system. There is a conspicuous difference between the characteristics of flow of water vapour and oil vapour in a high vacuum conducting tube. We may, in many cases, consider that water vapour follows the Knudsen's flow equation in a high vacuum conducting tube. Oils and greases, however, can not usually be treated with the Knudsen's flow equation; it will take a long time for them to reach the stationary flow.
Solubility, super-solubility and specific gravity of triglycine sulphate are first determined to prepare mother solution for the crystal growth. From the results of supersolubility measurement, meta-stable region of this crystal is found to be narrower than that of rochelle salt, and therefore better result is expected by growing in static condition. As the temperature gradient of the solubility is large, the cooling method suits the growth. Since this crystal has the Curie point at about 50°C, evaporation method is used this time for the growth to ascertain the difference in properties of crystals grown in ferroelectric and paraelectric states, namely below and above the Curie point.
The existing theory for measuring the radius of small spherical paticles based on higher-order Tyndall spectra is fundamentally defective in that the energy distribution of light scattered by particles is assumed to be too simple. In fact, the distribution becomes complicate, as χ(=2πR0/λ(0)) or γ (the angle) increases. By calculating the chromaticity coordinates of light scattered by particles of 0.40, 0.50, 0.55 and 0.65 μ in radius, and 1.33 in reflactive index, the following conclusions are obtained: 1. Although the theory is defective, the results have few errors; most angles for red given by the theory are in the region of yellowish orange to pink in the chromaticity diagram, and there are no ranges of angles in that region in the diagram which do not include the angles for red. 2. Scattered light is often reddish in the range of angles where J1 (628)/Jl (523) is larger than 1.0.
The differential equation of a linear heat flow with surface radiation which determines the temperature distribution on a uniform wire or plate is _??_where θ is the absolute temperature of the wire, x is the distance along the wire and other constants are given by physical properties of the wire and boundary conditions. It appears that tedious calculations are inevitable to obtain a numerical solution of this equation, the analytical solution of which can not probably be expressed in terms of well-known functions. The author of this article describes that the general solution of this can be shown as the following integral, by normalizing B and x, and setting the origin of x on the extreme point of θ _??_ where _??_, η and _??_ are normalized x, y and extreme value of η, respectively. Several graphs, which show the above integral in practically applicable range with ηo taken as a parameter, are developed and illustrated. Nomographs which permit easy transformations of equation are also shown. Using these diagrams, one can immediately obtain the temperature distribution corresponding to various conditions.