Showing papers in "Japanese Journal of Applied Physics in 1975"
TL;DR: The point-diffraction interferometer as discussed by the authors is an inter-ferometer for measuring phase variations in which the reference wave is produced by a point discontinuity in the path of the beam.
Abstract: The point-diffraction interferometer is an interferometer for measuring phase variations in which the reference wave is produced by a point discontinuity in the path of the beam. Its simplicity makes it very suitable for testing instruments in situ, and some such tests are described. The general theory shows that other diffracting apertures can be used and relates the technique to phase-contrast microscopy and to scatter-plate interferometry.
235 citations
97 citations
TL;DR: In this article, calculational reconstruction of refractive index distribution from "multidirectional interferograms" is discussed and two approximate calculation formulae are given for two-dimensional case, one is derived using the Born approximation and corresponds to a generalization of the formula in X-ray structure analysis.
Abstract: Discussion is made of calculational reconstruction of refractive index distribution from "multidirectional interferograms." Two approximate calculation formulae are given for two-dimensional case. One is derived using the Born approximation and corresponds to a generalization of the formula in X-ray structure analysis. The other is obtained using Rytov's approximation and a generalization of straight path approximation.
84 citations
TL;DR: In this article, the authors investigated the mechanism of the killer effect of iron group ions (M2+) on the green luminescence in ZnS:Cu, Al phosphors, the dependences of the intensity and decay rate of the green lumininescence on the M2+ concentrations, and some other related optical properties are measured.
Abstract: To investigate the mechanism of the killer effect of iron group ions (M2+) on the green luminescence in ZnS:Cu, Al phosphors, the dependences of the intensity and decay rate of the green luminescence on the M2+ concentrations, the relation of the green luminescence intensity vs. excitation intensity, and some other related optical properties are measured. It is concluded, together with some theoretical calculations, that the killer effect of Mn2+ ion is mostly due, especially at low temperatures, to the resonance energy transfer. In the cases of Fe2+, Ni2+, and Co2+ ions, it is concluded that the killer effect is caused not only by the energy transfer but also by the bypassing process via deep levels created by these ions, and that the effect due to the bypassing process is enhanced with increasing temperature.
73 citations
TL;DR: In this article, the authors observed that the temperature distribution in the double-heterostructure laser under cw operation differs from that below the threshold; that is, the narrowing of the distribution around the active region was observed above the threshold.
Abstract: The temperature distribution in the double-heterostructure laser under cw operation was observed directly. The temperature distribution above the threshold differs from that below the threshold; that is, the narrowing of the distribution around the active region was observed above the threshold. This means that the heat source is concentrated at the active region when the diode lases. The dependence of the temperature rise on the differential quantum efficiency was also observed. These results can be understood qualitatively by assuming a change in thespatial distribution of the heat source in the double-heterostructure laser below and above the threshold.
72 citations
TL;DR: In this paper, the carrier mobilities of several insulating polymers such as PET, PS and PS were studied by the time-flight method using pulsed electron beam bombardment.
Abstract: Carrier mobilities of several insulating polymers such as PET, PS were studied by the time of flight method using pulsed electron beam bombardment. For example, the mobilities obtained in an electric field of 1~2 MV/cm were 2×10-5 cm2/Vsec for the electron and 1×10-4 cm2/Vsec for the hole at 27 °C in PET with the activation energy around 0.3 eV. At low field mainly the slow carrier component due to detrapping was observed, which apparently gave a much lower mobility. The carrier lifetime was also estimated from the Hecht curve. It was found that the quantum yield (number of induced carriers per impinging electron) was influenced seriously by the molecular structure.
64 citations
TL;DR: The perovskite-type compounds LaNiO3 (M: Ca, Sr and Ba) were synthesized and their crystallographic, electric and thermochemical properties were investigated as discussed by the authors.
Abstract: The perovskite-type compounds La1-xMxNiO3 (M: Ca, Sr and Ba) were synthesized and their crystallographic, electric and thermochemical properties were investigated. The regions of perovskite formation were determined. The solubility limits or alkaline earth elements into La sites are around 5% for Sr and Ba, and less than 1% for Ca. The charge compensation of divalent ion substitution into a trivalent La ion site takes place by the formation of oxygen ion vacancies. Lanthanoid elements other than La did not form perovskite-type oxides. The compound LaNiO3 undergoes a rhombohedral-cubic transition at 940?C and decomposes above 1120?C. Resistivity of LaNiO3 is 9?10-3 ?cm at room temperature and increases as the temperature is raised.
56 citations
TL;DR: Anomalous Faraday rotations of the following three series of polycrystalline garnets were measured; 1) Gd3-xBixFe5O12, 2)Gd2Bi1Fe5yGayO12 and 3) Y2.25Bi0.75Fe5-yScyO12.
Abstract: Anomalous Faraday rotations of the following three series of polycrystalline garnets weremeasured; 1) Gd3-xBixFe5O12, 2) Gd2Bi1Fe5-yGayO12 and Gd2Bi1Fe5-yInyO12, and 3) Y2.25Bi0.75Fe5-yGayO12 and Y2.25Bi0.75Fe5-yScyO12. In series 1 and 2, the rotations were measured in the visible region at room tentperature. The rotation of series 1 increased linearly with x up to x=1.4, and the magneto-optical figure of merit reached 23 deg (at 0.56 µm) in Gd2Bi1Fe5O12. It was found in series 2 that the further substitution of Ga for Fe up to y=1.0 slightly decreased the figure of merit. In series 3, the rotations were measured in the near infrared region at a low temperature (8K) and the results were analyzed by using a one-ton model.It was found that two transitions near 3.1 eV and 2.8 eV, which are related to octahedral irons and tetrahedral irons respectively, were responsible for the anomalous rotation. These transitions were tentatively assigned to oxygen-iron charge-transfer transitions.
52 citations
TL;DR: In this paper, a fine-powdered sample of high purity SnO2 gave a strong ESR signal (gav≈1.90) after reduction in vacuum.
Abstract: A fine-powdered sample of high purity SnO2 gave a strong ESR signal (gav≈1.90) after reduction in vacuum. This BSR center, like the g≈1.96 center of ZnO, is associated with the n-type conduction. When the sample was exposed to O2 or H2, the spin concentration, the full half width and also the electric conductance were changed. These variations are well explained by assuming that the fine-powdered SnO2 has double donor centers originated from both bulk and surface oxygen vacancies, The gav≈1.90 center may be due to the un-ionized deep donor electrons trapped in the surface oxygen vacancy.
50 citations
TL;DR: In this paper, a four-electrode cell was used to measure the contplex dielectric constant of polyelectrolytes including biopolymers, and the effect of frequency-independent d.c. conductance was eliminated.
Abstract: Difficulties in measuring the contplex dielectric constant of a highly conductive material such as aqueous polyelectrolytes including biopolymers arise from (l) electrode polarization effect and (2) d.c. conductance of the specimen which is very much higher than the conductance due to dielectric loss and drifts with time. A new method has been developed in which the first difficulty is avoided by employing a four-electrode cell and the second orue is overcome by direct measurement of the frequency difference spectrum of specimen impedance, ΔZ(ω)=Z(ω)-Z(ω0), between the measuring frequency ω and the reference ω0. By this procedure, the effect of frequency-independent d.c. conductance is eliminated. With the new method, the frequency range of dielectric measurement is extended from 0.2 Hz to 30 kHz.
44 citations
TL;DR: By cooling slowly a homogeneous solution of La, B and Al from about 1200°C, single crystals of lanthanum hexaboride (LaB6) were precipitated, and their lattice constant, purity and growh-orientations were investigated as discussed by the authors.
Abstract: By cooling slowly a homogeneous solution of La, B and Al from about 1200°C, single crystals of lanthanum hexaboride (LaB6) were precipitated, and their lattice constant, purity and growh-orientations were investigated. The products are needle-like crystals with a rectangular cross section, thin plate-like crystals and cubical crystals. The LaB6 crystal has the lattice constant 4.1564A and contains impurities of less than 0.01 wt%. More needle-like crystals with [110] growth direction tend to be formed than any crystals with other shapes. For the typical needle-like crystals, the crystal thickness depends on the cooling rate. The average size is 0.1 to 0.5 mm square in cross section and about 5 mm in length.
TL;DR: In this article, the authors examined the effects of HCl on generation of sacking faults and proposed a new oxidation mechanism, which gives rise to the vacancy (silicaon) flow from (to) the oxide silicon interface to (from) the faulted defect, to explain the elimination and shrinkage.
Abstract: Dislocation free silicon wafers, having a (100) plane surface, were oxidized in dry O2 (dry O2 oxidation) and dry O2+HCl (HCl added dry O2 oxidation) to examine the effects of HCl on generation of sacking fault. Frank (extrinsic) type stacking faults were caused by the oxidations. The defect size increased with increase of oxidation temperature at low temperature range and decreased with increase of oxidation temperature at high temperature range for both oxidizing atmospheres. Defect size was markedly smaller for HCl added dry O2 oxidation. Elimination and shrinkage of existing stacking faults occured during HCl added dry O2 oxidation. A new oxidation mechanism, which gives rise to the vacancy (silicaon) flow from (to) the oxide silicon interface to (from) the faulted defect, was proposed to explain the elimination and shrinkage.
TL;DR: In this article, a new method for ruling concave gratings that form stigmatic images in normal incidence spectrographs was developed and the results of the examination proved the possibility of producing mechanically ruled stigmatic concave grasps with the freedom of choosing stigmatic wavelengths is proved.
Abstract: Concave gratings that form stigmatic images in normal incidence spectrographs are analyzed and a new method of ruling stigmatic concave gratings has been developed. The ruling engine is numerically controlled for varying the groove spacings and is capable of ruling both straight and curved grooves. Three types of concave gratings, one conventional and two stigmatic have been ruled and the imaging properties of them are examined. From the results of the examination, the possibility of producing mechanically ruled stigmatic concave gratings with the freedom of choosing stigmatic wavelengths is proved.
TL;DR: In this article, structural properties of Si films formed by chemical vapor deposition onto amorphous SiO2 substrates have been examined over the temperature and thickness ranges of 650 to 900°C and up to 1 µm respectively.
Abstract: Structural properties of Si films formed by chemical vapor deposition onto amorphous SiO2 substrates have been examined over the temperature and thickness ranges of 650 to 900°C and up to 1 µm respectively. At 650°C the films were amorphous regardless of their thickness. At 700°C the 0.1 µm-thick films were amorphous, but the preferred orientation developed as the film thickness increased. Above 750°C 0.1 µm-thick films were seen to have a random orientation, and with increasing film thickness above 0.3 µm, the and orientations developed in the temperature ranges of 750 to 825°C and 825 to 850°C respectively. The influence of heating at elevated temperatures on film strutucres is also presented.
TL;DR: In this paper, a new grid pattern is observed in the region between the Williams domain and the turbulence at a lower frequency than the critical frequency, indicating that the transition from Williams domain to turbulence and from the chevron texture to turbulence are different from each other.
Abstract: The flow figures in the thin films of MBBA under the applied electric field are observed fromthe transverse direction. The aspects of transitions from the Williams domain to turbulence and from the chevron texture to turbulence are different from each other. A new grid pattern is observed in the region between the Williams domain and the turbulence at a lower frequency than the critical frequency.
TL;DR: In this paper, changes in the a-axis and the c-axis thermal resistivity of pyrolytic graphite caused by electron irradiation at 82 K and by subsequent isochronal pulse annealing have been measured.
Abstract: Changes in the a-axis and the c-axis thermal resistivity of pyrolytic graphite caused by electron irradiation at 82 K and by subsequent isochronal pulse annealing have been measured. The additive thermal resistivity at 78.5 K increases as 9.6×102N0.85f and (7.9±0.6)×103N0.75f cm deg/W in the a-axis and the c-axis directions, respectively, in the region of 2 ppm
TL;DR: In this paper, the crystal structure of high pressure phase of polytetrafluoroethylene (PTFE) has been determined by X-ray methods, and the fiber pattern of this polymer has been recorded on a cylindrical film at 5500km/cm2, 78°C.
Abstract: The crystal structure of high pressure phase of polytetrafluoroethylene (PTFE) has been determined by X-ray methods. A high pressure X-ray diffraction apparatus which enables to get the fiber pattern of crystalline sample under purely hydrostatic high pressure at high temperature has been constructed. A small specimen of PTFE fiber was held in the bore of a beryllium window for X-ray. The fiber pattern of high pressure phase of this polymer has been recorded on a cylindrical film at 5500km/cm2, 78°C. It is found that in this phase the molecules have a planar zigzag arrangement different from that of a helix at atmospheric pressure. The unit cell is orthorhombic, with a=8.73 A, b=5.69 A, c=2.62 A. The result of the X-ray diffraction studies agrees with that of the other physical properties of PTFE in high pressure phase.
TL;DR: In this paper, a resistive shell was applied to a tokamak to investigate the effect of the shell's relative radius on the stability of the system, and it was shown that the shell current induced by a small displacement of the current-carrying plasma column produces a restoring force, which contributes to the stabilization.
Abstract: The investigation of positional instabilities, that is, vertical displacement and horizontal expansion of the plasma loop, is extended to a tokamak with a resistive shell. The shell current induced by a small displacement of the current-carrying plasma column produces a restoring force, which contributes to the stabilization. The quantitative analysis of the effect due to the shell shows that the finiteness of the minor radius of the plasma column reduces the effective skin time of the shell τs from the intrinsic one. Consequently it is shown that although the stability condition is not altered, a resistive shell restrains the growth rate of the instability to the order of τs-1, in a wider region than the stable one.
TL;DR: In this article, a new model of the generation of the dislocation network associated with dark-line-defects (DLDs) in rapidly degrading double-heterostructure laser crystals is proposed.
Abstract: A new model of the generation of the dislocation network associated with dark-line-defects (DLDs) in rapidly degrading double-heterostructure laser crystals is proposed. The degradation can also be explained by this model, i.e., it may be associated essentially with the first stage of the development of the dislocation network which is based on the conservative propagation of screw dislocation segment and, thus, does not require point defect sources. The second stage of the development may be the widening and twisting of the trace of the dipole dislocation by a combination of climb and glide. The image of DLDs would thicken after the second stage of the development. The observed characters of DLDs such as directionality, existence of loops, and so on, can be well explained in the light of the new model.
TL;DR: In this paper, X-ray, dielectric and elastic measurements were made and the space groups were determined as I, T4-P213; II, C22-P21; III, C11-P1 and IV, D42-P212121 as the temperature is decreased.
Abstract: Tl2Cd2(SO4)3 undergoes phase transitions at –145°, –153° and –181°C successively. The X-ray, dielectric and elastic measurements were made. The [001] component of spontaneous polarization is almost independent of temperature between –145°C and –181°C, and the additional [110] component appears at –153°C and increases gradually with decreasing temperature. Below –181°C, the polarization vanishes. The dielectric constant and the elastic compliance coefficients show abrupt changes at the transition points. Using the extinction rules as well as the result of spontaneous polarization measurement, the space groups are determined as I, T4-P213; II, C22-P21; III, C11-P1 and IV, D42-P212121 as the temperature is decreased. This assignment agrees with the proposal of B\urezina et al.
TL;DR: In this article, an energy distribution of the electrons and the yield of high-energy neutral atoms were examined, and the discharge currents due to electrons and positive tons were separately, and electron current was divided into the secondary electron and thermal emission currents.
Abstract: In the sputtering of TiO3, the substrate exhibits an abnormal temperature rise and a considerable decrease in weight. To investigate these phenomena, an energy distribution of the electrons and the yield of high-energy neutral atoms were examined. Furthermore, the discharge currents due to electrons and positive tons were estimated separately, and the electron current was divided into the secondary electron and thermal emission currents. In BaTiO3. aconsiderable electron yield by thermal emission was detected. From the results obtained, the following conclusions maight be expected. The abnormal temperature rise of the substrate is due to many electrons impinging upon the substrate with relatively high energies, and the large yield of high-energy neutral atoms bombarding the substrate is responsible for weight diminution of the substrate.
TL;DR: In this paper, the authors used ellipsometry and measurements of transmissivity and reflectivity to obtain the optical constants of β-rhombohedral and amorphous boron and found that the values of the refractive index were between 300 and 335 for wavelengths between 035 µm and 120 µm.
Abstract: Optical constants of β-rhombohedral and amorphous boron were obtained by ellipsometry and by the measurements of transmissivity and reflectivity The values of the refractive index were found between 300 and 335 for wavelengths between 035 µm and 120 µm Absorption coefficient α of amorphous boron as a function of the photon energy \hbarω was found to follow the equation α=B(\hbarω-E0)2/\hbarω and constants E0 and B were 100 eV and 17∼21×105 cm-1·eV-1 respectively High temperature conductivity σ of amorphous boron was expressed in the form σ=C exp (-E/kT) and 2E and C were 104∼116 eV and 7∼12×103 ohm-1·cm-1 respectively Absorption of β-rhombohedral boron was considered to be caused by indirect transitions from valence band to conduction band From the temperature dependence of conductivity, the energy gap between valence band and conduction band was estimated to be 134 eV for β-rhombohedral boron
TL;DR: In this article, a one-dimensional photodiode array, whose diodes are connected differentially, is used instead of a parallel slit array, in order to remove the low frequency noise.
Abstract: A new method for non-contact velocimeter is proposed. A one-dimensional photodiode array, whose diodes are connected differentially, is used instead of a parallel slit array, in order to remove the low frequency noise. Then, the output signal of the differential detector is restricted to a narrow band signal, whose center frequency is proportional to the velocity of a rough surface. Since the output can be directly fed to a frequency counter, the restriction of the measurement range due to the cut-off frequency of the high pass filter is lifted. The characteristics of the proposed velocimeter are studied with the aid of spectrum analysis and some experimental results are shown.
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