bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature Dependence of the Viscosity Coefficients of Liquid Crystals
Authors: Imura Hidefumi , Okano Koji
Published: November 2005

Based upon the thermodynamics of irreversible processes a set of phenomenological equations which explain the temperature dependence of Leslie's viscosity coefficients of liquid crystals are presented. The equations are of the form α4=2η0exp
(E/k
T)+constant×S+O(S
2), in which S is the orientational order parameter and E is the activation energy which can be determined by viscosity measurements in the isotropic phase. The equations apply to the nematic phase in the case of finite S as well as to the isotropic phase in the limit of S=0. A fairly good agreement is found between the proposed equations and the existing experimental data.
Energy Distribution of Transmitted Secondary Electrons from Porous KCl Films
Authors: Ito Hideo , Yoshida Shigetomo
Published: November 2005

The energy distribution of transmitted secondary electrons from porous KC1 films was measured by an ac-retarding field method. The surface potential of the films was obtained from the peak position of this energy distribution. There were three distinct regions in the behavior of the secondary emission according to the surface potential and its distribution. In Region 1 the distribution range of the surface potential was quite small, and the yield increased exponentially with the surface potential. In Region 2 the distribution range of the surface potential increased rapidly with the collector voltage and the energy distribution of emitted electrons broadened. In Region 3 the energy distribution curve had approximately a Gaussian shape and seemed to be determined almost entirely by the distribution of the surface potential. A mechanism of the energy distribution was proposed using a channel electron multiplier model.
Uniaxial Stress Effect on p+-n Si-Ge Alloyed Heterojunction Characteristics
Authors: Ido Toshiyuki , Yoshida Akira , Arizumi Tetsuya
Published: November 2005

V-I characteristics of a p
+-n Si-Ge alloyed heterojunction were investigated at room temperature by applying a uniaxial stress up to 3.7×109 dyn/cm2 perpendicular to the junction plane. The changes in the applied voltage under constant current conditions become larger in order for <011>, <211>, <111> directions of the applied stress. The change in the applied voltage decreases with increasing the stress for <111> axis. For <011> and <211> it increases at first to a maximum value and then begins to decrease. The stress effect on V-I characteristics of the p
+-n, Si-Ge heterojunction is explained satisfactorily by considering the energy shifts in band edges.
Electrical Characteristics of Metal Al2O3–SiO2–Si (MAOS) Transistors
Authors: Nakagiri Masaru , Wada Toshio
Published: November 2005

The dependence of effective mobility and the threshold voltage of metal-aluminum oxide-silicon oxide-silicon (MAOS) transistors upon the thickness of silicon oxide (SiO2) and upon the ambient gas of heat treatment was examined.
The effective mobility of MAOS transistors, whose gate insulator film consists of a double layer of Al2O3 (about 1500Å) and SiO2 (20∼110Å), is 40∼460 cm2/V·sec depending upon the thickness of SiO2 and this value is small compared with 640 cm2/V·sec of MOS structure. However it increases up to 300∼650 cm2/V·sec after the heat treatment in hydrogen at 500°C for 4 hours. The small effective mobility of as-grown sample is caused by a large number of surface states near the conduction band edge. These surface states are likely related to a kind of acceptor type defects.
The Simulation of a Gunn Diode with Temperature Effects
Authors: Kamei Kiyoo , Nishi Yoshio
Published: November 2005

Computer simulation was made to give the design principle of a Gunn diode operated under CW oscillation. Temperature profile due to heat dissipation in the diode were considered in our calculations.
The great improvement of the efficiency can be achieved if we shorten the active layer and adopt an adequate concentration profile to compensate the effective high resistance toward the anode caused by the temperature gradient. For example, when the input power density was 8×107 W cm-3, the oscillation could not be expected in the case of the flat profile because the resistance near the anode increases severely. We obtained the efficiency over 4.5% by choosing the active layer length and raising the concentration profile linearly to the anode by 15∼20%.
ENDOR Experiments on Free Radicals in Solution
Authors: Yamamoto Takamitsu , Sato Kozo , Miyamae Teruo
Published: November 2005

The ENDOR spectrum of Coppinger's radical was obtained by a 20–30 watt rf, which was frequency-modulated at 6.5 kHz in the room temp. - liq. N2 temp. range. The frequency of magnetic modulation was 100 kHz or 80 Hz. Details of the ENDOR spectrometer are given, and the temperature and concentration dependence of the ENDOR signal intensity are examined. In employing high frequency magnetic field modulation, the passage condition must be taken into consideration.
Viscosity of Concentrated Solution
Authors: Furuse Hisamoto
Published: November 2005

The viscosity of a solution (or suspension) as a function of concentration has been formulated from a reassessment of Einstein's original work. Solute molecules are assumed rigid, spherical and fairly large compared with solvent molecules. Starting from the flow pattern around single spheres, the principle of superposition has been used to calculate the pattern for multi-particles having a size distribution. The applicability of the equation in predicting the viscosity of a concentrated rather than dilute solution characterized by a size distribution in solute molecules has been suggested theoretically and confirmed by experiments.
Molecular Arrangement of Nematic Liquid Crystals
Authors: Uchida Tatsuo , Watanabe Hideo , Wada Masanobu
Published: November 2005

The molecular arrangement of twelve types of nematic liquid crystals is observed on the surfaces of the supporting plates of soda-, pyrex-, or quartz-glass. These surfaces are treated with various methods. The impurity APAP or EBPAP added to the nematic liquid crystals promotes the molecular alignment perpendicular to the glass plate. A mechanism of the molecular alignment of nematic liquid crystals on the glass surface is discussed in connection with the molecular structures of nematic liquid crystals based on the experimental results.
Molecular Orientation Effects in Compensated Liquid Crystals
Authors: Sato Susumu , Wada Masanobu
Published: November 2005

An optical and a dielectric memory effect is observed in compensated mixtures of cholesteryl chloride and cholesteryl laurate. When the temperature is increased after a sufficiently high dc electric field is once applied and then reduced to zero at low temperatures, the liquid crystal becomes transparent and the dielectric constant becomes maximum at a temperature approaching the cholesteric to nematic phase transition temperature. This effect can be erased by heating up to an isotropic state. The phase transition from the homeotropic to the plane texture is observed by applying the high frequency electric field. The critical frequency depends upon the sample temperature and it varies from 3 kHz to 500 kHz as the temperature rises from 17°C to 50°C. These phenomena are discussed based on the orientation effects of liquid crystal molecules.
Influence of Al2O3 Deposition Temperature on Charge-Storage and Retention in MA(O)S Structures
Authors: Tsujide Tohru , Iida Kiyoto
Published: November 2005

The influence of the deposition temperature of Al2O3 on the characteristics of MAS (metal-Al2O3-Si) and MAOS (Metal-Al2-SiO2-Si) memory devices is investigated. It is found that the films deposited below 700°C exhibit high conductivity lowering the high frequency capacitance of MAS and MAOS structures below their quasi-equilibrium minimum values in the C-V characteristics when the depleting bias voltage is applied beyond a certain value. In the case of MAOS structures the direction of the flat-band voltage shifts under positive bias changes from positive to negative with increasing SiO2 thickness. No distinguishable change in the charge storage characteristics is observed among the films deposited at 800, 900 and 950°C. Also it is observed that the faster the charge retention, the lower the deposition temperature for both MAS and MAOS structures.
Modified Luneburg Apodization Problem. II
Authors: Kusakawa Tohru
Published: November 2005

A new apodization problem which is an extension of the previous apodization problem solved by the author is defined and solved. The method used here is a slightly modified version of that used in solving the previous problem. The problem is to find the pupil function which minimizes the dispersion factor subject to the condition that the Strehl definition must have a certain prespecified value.
Pattern Classification Using Correlation with Random Mask
Authors: Yatagai Toyohiko , Ishihara Satoshi , Kato Hisatoyo , Tanaka Shun-ichi
Published: November 2005

An optical apparatus for the pattern classification consisting of two steps of training and classification was made. Holographic cross-correlation of training patterns with a random mask was used to make the filters for classification. Although the error of classification was 13% in this experiment, a computer simulation of the optical method which gave a completely correct classification showed the effectiveness of this method. Effects of the characteristics of a photographic emulsion and of the displacement errors of the patterns and correlation filters were also discussed.
Infrared-Microwave Double Resonance in H2CO with a Zeeman-Tuned 3.5µm He-Xe Laser
Authors: Takami Michio , Shimoda Koichi
Published: November 2005

Infrared-microwave double resonance effects in formaldehyde are observed by using a method of microwave pumping and infrared detection. The pressure dependence of the double resonance signal is observed with the gas cell either inside or outside of the laser cavity. The signal is observed to change its sign at a low pressure of formaldehyde. A rate-equation approach is used to calculate the pressure dependence of the double resonance signal. The observed change in sign is explained by higher-order effects of double resonance. A good agreement between the theoretical and the observed results is obtained.
The double resonance effects on the inverted Lamb dip of the infrared absorption of formaldehyde are also observed. The dip splits into a doublet when the strong resonant microwave is applied.
Photon Drag Effect in Germanium
Authors: Hattori Hazime , Umeno Masayoshi , Jimbo Takashi , Fujitani Osamu , Miki Shichiro
Published: November 2005

It is described how the photon drag voltage in germanium varies with hole concentration and how it depends on temperature. Also some considerations are taken into the following additional contributions similar to the photon drag effect: (1) the Thomson effect, (2) the hot carrier effect and (3) the diffusion effect. Experiments were performed by using a Q-switched CO2laser. This photon drag effect provides a convenient detector for use with Q-switched CO2lasers and mode-locked CO2lasers, because it operates with the high speed response time smaller than 10-10s at room temperature. In the case ofp-type germanium with the resistivity of 2.3 Ω-cm and the size of 1.5×1.5×20 mm3, its responsivity (R) is 3×10-6(V/W) and the detectivity (D) is 1.4×103(W-1) at room temperature and 1.1×104(W-1) at 77 K.
Millimeter-Wave Frequency Response of Hot Electrons in n-Type GaAs
Authors: Abe Masayuki , Kaneda Shigeo
Published: November 2005

Theoretical and experimental studies of millimeter-wave frequency response of hot electrons in n-type GaAs are performed. In the theoretical analysis, the transport properties of hot electrons under a high electric field superimposed with a small microwave field are investigated by using the transport equations with the assumption of a displaced Maxwellian distribution function. The experimental study is carried out by the electrodeless method which is especially contrived by the authors. Conclusively, the experimental results for 50 GHz millimeter-wave frequency responses of both the microwave conductivity and the microwave dielectric constant almost agree with the theory quantitatively.
Study of Fast Ionization Gauges Using an Electron Beam Fluorescence Probe
Authors: Ohba Kenkichi , Hirano Keiichi
Published: November 2005

Ionization gauges with rapid response are developed to study the transient behavior of rarefied gas puffs injected from a fast acting gas valve. A standard densitometer is provided by detecting fluorescence signals in the puff stimulated by a 23 kV electron beam. It is found that a usual opened-6AH6 gauge is not available for a fast ionization gauge since disturbances caused by the gauge head itself in the puff flow give some unfavorable effects on measurements. Four simple-shaped gauge heads of different types are newly designed so that the gas puff may flow smoothly through them. A negative feedback loop is connected to the grid electrode to stabilize the electron current. The gauge head with three co-axial grid-like electrodes and a hair-pin filament in its center is found to record the behavior of puffs accurately in the pressure range from 10-3 to 1 Torr.
Growth of Craters on Ion Etched Surface of LiNbO3 and Ion Etching without Craters
Authors: Yasuda Hiroshi , Nagai Kazutoshi
Published: November 2005

Abstract-A LiNbO3 single crystal for acousto-optic deflectors was etched by ion beam techniques. A number of craters were observed on a 15µm etched surface. It was found that they grew during ion etching with ions incident normal to the surface. Their average diameter was estimated to be 40µm and their average depth to be 1∼2µm. An explanation for the growth of the craters was proposed by taking account of the dependence of the etching rate on the localized angle of the incident ions. Experimental conditions under which a smooth surface can be obtained were discussed. The experimental results were in agreement with the theoretical prediction.
Dislocation Etch Hillock Formation in White Tin Single Crystals
Authors: Honda Katuhiko , Hirokawa Tomoo
Published: November 2005

The mechanism for producing pyramidal etch hillocks at the sites of dislocation on the {001} surface of white tin is studied. The hillock formation results from the etch resistant materials existing at the dislocation sites on the crystal surface. These materials come from (1) the segregation of impurities contained in the crystal itself along the dislocation lines, and (2) the precipitation of copper or silver atoms contained in the etching solution at the clean dislocation sites. The role of impurities to produce hillocks is demonstrated and the mechanism for the development of hillocks is derived from the nature of dissolution of the {101} surface enclosing hillocks. Application of this mechanism to another crystal is suggested.
Microwave Oscillation in Germanium Avalanche Diodes I
Authors: Takeshima Masumi
Published: November 2005

The intermediate signal theory of the microwave oscillation in avalanche diodes is presented. The formulae describing the oscillation characteristics are derived on the basis of this theory and compared with the experimental results obtained from germanium diodes having linearly graded junctions. It is found that calculations of the output power using the small signal impedance parameters with no aid of a computer are quite successful in predicting the critical magnitude of output power in the practical range of oscillation.
Analysis of Electrical Characteristics of the Nonequilibrium MHD Generator by the Four-Terminal Network Theory
Authors: Shirakata Hirofumi
Published: November 2005

The basic circuit equivalent to the two-dimensional Ohm's law is expressed as the active network including a current-voltage transducer and a negative resistance. The network for a multi-electrode Faraday generator with the flow of three layers consisting of a free stream layer and two boundary layers is derived by combining the basic equivalent circuits.
The steady state solutions of currents, voltages and electron temperatures in the nonequilibrium generator are obtained. In the calculation the loss mechanisms due to electrothermal instability, boundary layer and wall-leakage currents are considered. From the results of the numerical calculation it is found that the instability has an important role in reducing the electron temperature difference between a free stream and a boundary layer and in preventing the boundary layer leakage current. The theoretical and the experimental results are in good agreement.
Piezoresistive Properties of Polycrystalline Silicon Thin Film
Authors: Onuma Yoshiharu , Sekiya Kunihiko
Published: November 2005

Intending to use semiconductor films for piezoresistive elements, polycrystalline silicon films are prepared by electron bombardment method on insulating substrates and electrical properties of the films are investigated. Gage factor of the film is in the vicinity of 25, temperature coefficient of resistance and gage factor is about 1.8×10-4/°C, 1.1×10-3, respectively, for the resistivity of an order of 10-3 Ω cm. Much smaller coefficients are obtained by heat treament.
Depletion-Layer Transduction of Surface Waves on Piezoelectric Semiconductor
Authors: Takada Susumu , Hayakawa Hisao , Ishiguro Takehiko , Mikoshiba Nobuo
Published: November 2005

Effective generation and detection of surface elastic waves on semiconducting GaAs are achieved by using the depletion-layer which avoids the screening of piezoelectric fields by free carriers. A pair of interdigital transducers is constructed by evaporating Au on the (111) plane of GaAs, resulting in the formation of the Schottky barrier under the electrodes of the transducers. The surface wave of 25 MHz is propagated along the <110> direction. Applying the d
c bias voltage to the Schottky barrier, the signal level is increased up to 30 dB. A fairly good agreement is obtained between an analysis and the experiments.
Ferromagnetic Resonance in Polycrystalline Mn1+xSn
Authors: Sato Nobuyasu
Published: November 2005

The experiments of ferromagnetic resonance in polycrystalline Mn1+xSn which has hexagonal crystal structure are carried out with spherical and powdered samples in a temperature range of 273K∼120K. The anisotropy constants are obtained by comparison of experimental curves with theoretical ones, which are calculated with the assumption that the anisotropy field is more important than the demagnetizing field. The comparison indicates that the preferred direction of magnetization of these compounds are along the hexagonal axis and the value of first order anisotropy constantK1of Mn1.5Sn at 150K is 4.8×105erg/cm3.
Study of Silicon-Silicon Dioxide Structure by Electron Spin Resonance II
Authors: Nishi Yoshio , Tanaka Kiyoshi , Ohwada Atsushi
Published: November 2005

Effects of the paramagnetic center observed at Si-SiO2 interface on the surface electron transport in MOSFET and MOS Hall devices are investigated. It is concluded that (1) surface mobility of electrons in the triode region decreases with decreasing partial pressure of water in oxygen for gate oxidation, which corresponds to increase in the density of the paramagnetic center. (2) when the density of the paramagnetic center is in the order of 1013cm-2, some amounts of the induced electrons at the surface seem to be captured by the traps which are associated with the center. (3) the surface mobility in the triode region can be explained by the Coulomb scattering due to the ionized center, the density of which is proportional to the density of the paramagmetic center.
Pivoted Slider Bearing with Convex Pad Surface in Micropolar Fluid
Authors: Datta Ahi Bhushan
Published: November 2005

A theoretical analysis is presented for a pivoted slider bearing in a micropolar fluid which can sustain antisymmetric stress and couple stress. The effect of pad-surface curvature on pressure, load capacity, centre of pressure, and friction coefficient is determined and is shown in a family of curves. It is found that the load supporting capacity in this fluid is more than that in the Newtonian fluid.
Vapor Growth of InAsxP1-x
Authors: Mizuno Osamu , Arai Ken'ichi
Published: November 2005

Epitaxial InAs
x
P1-x
layers have been grown on GaAs, InAs and InP substrates using the InAs–AsCl3–InP–PCl3–H2, InAs–HCl–InP–HCl–H2 and In–AsCl3–In–PCl3–H2 vapor phase systems. It has been clarified that in these systems the grown layer composition x is dependent only on the gas composition (ratio of As/(As+P) in gas phase) and is independent of the other growth parameters, growth temperature, reactant gas concentration, hydrogen flow rate, substrate material, crystallographic orientation of substrate and growth system. The equilibrium constants of the growth reactions for InAs and InP have been obtained experimentally.
A thermodynamical calculation for the vapor growth of InAs
x
P1-x
has been carried out. Good agreements between experimental results and calculated results have been obtained. An interaction parameter of 3000 cal/mole for InAs–InP alloy is suggested.
Raman Scattering in Amorphous As-Se System
Authors: Mori Tatsuo , Onari Seinosuke , Arai Toshihiro
Published: November 2005

Raman spectra of amorphous As
x
Se1-x
system (0≤x≤0.5) were measured and the spectra were interpreted with the molecular model of Lucovsky and Martin. In the Se-rich region the observed Raman spectra are well reproduced by the superposition of the Raman intensity of pure Se, As2Se3 and As2Se4 in proportion to x. In the As-rich region the Raman spectrum at x=0.45 is well described by the average of those at x=0.4 and 0.5.
The amorphous state of As
x
Se1-x
for 0<x<0.4 is shown to be composed of a Se8 ring, Se
n
chain, AsSe3 unit and As2Se4 unit.
In the As-rich region, the local structure change due to the substitution of As and Se is small.
Sintering of Ultrafine Metal Powders. I. Coalescence Growth Stage of Au and Ag
Authors: Iwama Saburo , Sahashi Toshio
Published: November 2005

Sintering of ultrafine powders of Au and Ag, produced by a gas evaporation technique, has been studied by the electron microscopy and X-ray diffraction methods. The critical temperature, above which the particle size increases, is found to be room temperature for Au powders and 60°C for Ag powders with a particle size of about 200 Å. Retardation of sintering is observed for both Au and Ag powders exposed to air before heating. Decrease of strains as well as stacking disorders with increase of temperature is detected by X-ray diffraction and electron microscopic study. Experimental formulae for the variations of particle size and strain with temperature are obtained from the half-value breadth of X-ray diffraction profile. Particle size effect on sintering is also examined for Ag powders.
Nonlinear Mechanism of I-V Characteristics of MBM Diodes in Low Voltage Region
Authors: Nagashima Akira , Akahane Tadashi , Tako Toshiharu
Published: November 2005

The current-voltage characteristics of point-contact metal-barrier-metal diodes, the asymmetric nonlinearity of which corresponds to the rectifying property for a radiation field, are studied using a one-dimensional electron tunneling scheme through the barrier between the surfaces of the contacted metals. Anumerical calculation with accuracy higher than the Wentzel-Kramer-Brillouin approximation shows that the barrier asymmetry cannot account for the measured nonlinearity in the low bias voltage region V
b≪φ/e. In this paper, the electron densities of the states of each contact metal are included in the explanation of the rectifying property, and the calculated results agree well qualitatively with the measured nonlinearity of W-Ni, W-Co, and W-Rh diodes.
Excitation Process of the N2 IR (B3Πg-A3Σu
+) Laser Transition
Authors: Yasuda Yukio , Sokabe Noburu , Murai Akira
Published: November 2005

Excitation mechanism of the laser action on the first positive system (B
3Πg-A
3Σu
+) of N2 molecule is studied with an emphasis on the time relationship between the ir and uv (C
3Πu-B
3Πg) laser pulses. Pressure dependence of time lag between the uv and ir pulses has been observed in the pressure range from 4 to 8 Torr using an axial-discharge tube. The observed time lag is well predicted by a model which involves direct electron-impact excitation, near-resonant collisional excitation transfer from the a
1Πg state, and cascade excitation due to the uv laser action for the upper ir laser level. Relative importance of these excitation processes depends primarily on N2 pressure.
Transmitted Information of TLD Elements
Authors: Uchida Suguru , Inatsu Hiroshi , Fujita Hiroshi
Published: November 2005

The performance of four types of very small thermoluminescence dosimeter (TLD) elements is evaluated by means of the entropy method which is considered to be the evaluation on the basis of the precision of measurements. Evaluation for four types of TLD elements is ranked by the amount of transmitted information (TI). A standard deviation of the measured data for each type of element is also calculated and compared with TI. The overlapping degree between the adjacent distributions of output data corresponding to each of the different inputs is evaluated by the entropy method and represents the uncertainty degree of the data.
Temperature Measurements of Rarefied Gases by the Metastable Time-of-Flight Technique
Authors: Matsumura Shozo
Published: November 2005

By using the metastable time-of-flight technique (MTOF), experiments were carried out to determine the temperatures of extremely rarefied Ar and N2 gases at temperatures ranging from 300 to 550 K and at pressures of 10-5 Torr or lower.
Temperatures were calculated from the time spectra obtained for Ar gas within the accuracy of ±3 K on the assumption that the Ar atoms excited onto the metastable states have a Maxwellian velocity distribution.
Temperatures of N2 gas were obtained also within the accuracy of ±3 K; in this case some metastable states of N2 molecules are considered to have a mean life time of 160 µs due to radiative decays.
Surface Analysis of LaB6 Single Crystal Thermionic Emitters
Authors: Nakazawa Masatoshi , Futamoto Masaaki , Hosoki Shigeyuki , Usami Katuhisa
Published: November 2005

Surface analysis of heated LaB6 thermionic emitter is made by means of Auger electron spectroscopy. Changes in surface state with changing emitter temperature and ambient oxygen pressure are investigated. The emitter temperature is varied from room temperature to 1700°C, and the oxygen pressure from 1×10-5 Pa to 7×10-3 Pa. With the increase of temperature the emitter surface passes through four states depending on oxygen pressure, before it reaches a clean state. Among them a state is particularly noteworthy that the emitter surface is covered with a layer of lanthanum oxide just before assuming the clean surface state. A surface state diagram is shown. The optimum conditions of emitter temperature and oxygen gas pressure to exhibit high emission properties are described.
An Investigation of the Si(111) 7×7 Surface Structure by RHEED
Authors: Ino Shozo
Published: November 2005

A clean Si(111) surface showing a 7×7 superlattice structure has been investigated in detail by RHEED with changes of azimuthal angle, glancing angle, and surface temperature. For the 7×7 structure, the mean intensity distribution of the reciprocal lattice rods was estimated from the intensity analysis of various RHEED patterns. A Patterson function was calculated using the mean intensity distribution. A new structural model which satisfies the Patterson function has been obtained. This model contains some scattering matter arranged in a regular triangular form with side 2a, a being the size of the substrate unit mesh. The intensity distributions calculated from this model agreed well with that obtained from RHEED and LEED patterns.
Elastooptic Effect in BaTiO3
Authors: Tada Kunio , Kikuchi Kazuro
Published: November 2005

The temperature dependence of the elastooptic coefficient in BaTiO3 is theoretically and experimentally investigated in the vicinity of the cubic-tetragonal phase transition point (∼113°C). A theory of the elastooptic effect in BaTiO3 is developed through the anharmonic potential method. It is shown that nonlinear coupling among the electronic polarization, strain and soft phonon causes the temperature dependence of the elastooptic coefficient.
The elastooptic coefficient p
11 of a poled BaTiO3 single crystal is measured by the Dixon-Cohen method as a function of temperature near the phase transition point. In the tetragonal phase, p
11 is almost temperature-independent, whereas in the cubic phase, p
11 is strongly dependent on temperature. The above theory accounts for these experimental results.
The Relationship between Signals and Graininess on Radiographs
Authors: Uchida Suguru , Kozima Katuyuki , Tanaka Kazuo
Published: November 2005

The relationship between signals and graininess on radiographs is discussed here in the following report. It has been reported so far that the signals are reproduced by Fourier inverse transform even though the spectra of signals are cut off. For this reason, it is considered that the intensity of light which is transmitted through films makes the products of the signals and the radiographic mottles. In opposition to these, however, the following could be obtained experimentally. Those products which are made by the signals are the grains of films out of the radiographic mottles, and the brightness of reproduced images is related to the size of grains.
Photon Assisted Tunneling in SiC LED's Prepared by Overcompensation Method
Authors: Ikeda Mitsushi , Matsunami Hiroyuki , Tanaka Tetsuro
Published: November 2005

Peak shifts of electroluminescence spectra from red to blue are observed in heavily doped 6H SiC LED's with a linear and a quadratic impurity profiles prepared by the overcompensation method. The mechanism is studied based on the electrical properties, injection mechanisms, and luminescent properties. Most of the characteristics are explained by the photon assisted tunneling model.
Large Signal Monte Carlo Simulation of Electron Transport in GaxIn1-xSb
Authors: Kawashima Mitsuo , Tomizawa Kazutaka
Published: November 2005

Electron transport under a large amplitude RF field in Ga
x
In1-x
Sb has been simulated by the Monte Carlo method, to examine the validity of the assumption usually employed in the microwave heating experiment to obtain the velocity-field curve. The result indicates that a large relaxation time from the upper to the lower valley, about 35 ps for x=0.7, makes it invalid to assume an instantaneous electron response to the applied microwave field at 35 GHz. It also shows that an apparent velocity-field curve with negative differential mobility characteristics may result if the conventional procedure is applied, neglecting the relaxation effect.
The Role of a Photoresist Film on Reverse Gas Plasma Etching of Chromium Films
Authors: Yamazaki Teruhiko , Suzuki Yoshiki , Uno Jun , Nakata Hidefumi
Published: November 2005

The role of a photoresist film on reverse gas plasma etching of chromium photomask plates has been studied. The variation of etching profiles has been observed using SEM techniques. It is speculated that a WO3 layer on the chromium film forms a masking layer to the etching and that the WO3 layer can be removed by decomposition of the photoresist film in the plasma. A study of the relation between photoresist thickness and etching time has shown that there is an optimum photoresist thickness for each WO3 concentration in the chromium film.
Barrier Parameters of Tungsten-Nickel Point Contact Diodes
Authors: Yasuoka Yoshizumi , Yasuoka Tomokazu , Sakurada Tomomi
Published: November 2005

Current-voltage and current-temperature characteristics of tungsten-nickel point contact diodes with interface barriers 500 to 1500 A thick are investigated in order to obtain the contact area and barrier heights on each side. It is found that the barrier height on the nickel side is about 0.39 eV and that on the tungsten side is about 0.34 eV, and that the contact area is of the order of 1×10-11 to 1×10-12 cm2.
Metal Impurity Reduction by Working Gas Injection in a Tokamak
Authors: Maeno Masaki , Suzuki Norio , Yamamoto Takumi , Fujisawa Noboru
Published: November 2005

Reduction of metal impurities in the JFT-2 tokamak is studied. The possibility of cooling the scrape-off plasma by injection of a working gas has been studied as a method of reducing the metal impurities introduced by sputtering. The relations among the electron temperature of the scrape-off plasma, the line intensity of Mo and the radiation power loss are examined in both injection and interruption of the working gas, and the effects of gas injection on fluctuations are also examined. Injection of a working gas decreases the electron temperature of the scrape-off plasma, which in turn decreases both the production of metal impurities due to sputtering and the radiation loss power. Gas injection also has a good effect on fluctuations.
Automated Calibration System for Lead Glass Counters
Authors: Imori Masatosi , Kobayashi Tomio , Takeda Hiroshi
Published: November 2005

An automated calibration system for lead glass counters has been developed. It has been used to calibrate about 2800 lead glass counters for the JADE experiment at DESY. In this article, we describe the configuration of the system, its control program and the calibration procedures.
Formation of Ultrafine Metal Particles by Gas-Evaporation VI. Bcc Metals, Fe, V, Nb, Ta, Cr, Mo and W
Authors: Saito Yahachi , Mihama Kazuhiro , Uyeda Ryozi
Published: November 2005

The crystal structures and habits of bcc metal particles have been investigated systematically by electron microscopy. The habits for the bcc structure are rhombic dodecahedra truncated by six {100} faces with various degrees of truncation from 0 to 100%. The truncation degree for Fe and V particles grown in the intermediate zone of a metal smoke is in good agreement with that for the Wulff polyhedron expected from the surface energies calculated for {110} and {100} faces. Particles of Cr, Mo and W have the A-15 type structure besides the ordinary bcc structure. The present results support the hypothesis that the A-15 type structure is stable when the particle size is small. The habits for the A-15 type structure are rhombic dodecahedra (Cr), {211} icositetrahedra (Cr and Mo) and rounded cubes (Mo and W).
Plastic Deformation in Highly-Concentrated KCl-KBr Solid Solution Single Crystals from 1.6 K to 923 K
Authors: Sakamoto Masao , Yamada Tomoharu
Published: November 2005

Compression tests are performed on KCl-
9∼92 mol% KBr crystals with dynamic observation of the group motion of dislocations using a polarizing microscope to examine the stress birefringence pattern. With increasing temperature, the yield stress τy decreases rapidly below 350 K but has a plateau region from 350 K to 750 K and decreases again rapidly above 750 K. The relation τy∝c(1-c), where c is the concentration of KBr, is found above 79 K. The yield stress below 350 K is controlled by the thermally-activated motion of dislocations overcoming concentrated solute atoms. In the plateau region, intermittent progression of edge dislocation walls, which induces serrations in the stress-strain curves, is observed using the birefringence, and the stress change due to the strain-rate change tests almost equals zero. These results are in good agreement with the theory of plateau stress [Jpn. J. Appl. Phys. 17 (1978) 251].
Constant Current Characteristics in White Light Lasers
Authors: Fujii Kan-ichi , Takahashi Tsutomu
Published: November 2005

The constant current characteristic means a V-I property parallel to the voltage axis. This characteristic appears by the replacement of He ions with Cd+ ions in the cathode dark space of a He-Cd glow discharge. The hollow-cathode structure which is used for a He-Cd+ white light laser facilitates this action since within the hollow-cathode the amount of Cd vapor is large. The mechanism of the constant current characteristic is discussed in terms of discharge physics and a calculation of the constant current value is attempted by heat balance method.
Effects of Ambient Gases on Surface Profile and Related Properties of Amorphous Alloy Ribbons Fabricated by Melt-Spinning
Authors: Matsuura Makoto , Kikuchi Makoto , Yagi Masaaki , Suzuki Kenji
Published: November 2005

This report describes the surface profile, magnetic properties and thermal stability of amorphous Fe78Si10B12 ribbons fabricated by melt-spinning using a copper roll in vacuum, He, Ar, N2 and air. Ribbons fabricated in Ar, N2 or air have surface profiles with long deep scratches due to gas bubbles injected along the melt-roll interface, while the scratches on the surface profiles of ribbons fabricated in He or vacuum are greatly reduced in a number and size. The different characteristics of the surface profiles are associated with improvements in the magnetic and thermal properties of the ribbons fabricated in He or vacuum.
Effects of Break-Up Ratios and Distribution Functions of Specific Size on the Mean Specific Size of Cluster Ions
Authors: Enjoji Hiroshi
Published: November 2005

The effects of break-up ratios and distribution functions of specific size on the relation between the mean specific size of nitrogen cluster ions and ionizing electron current have been theoretically investigated. The theoretical values of the mean specific size are about 100 to 200% of the experimental ones under suitable experimental conditions. The break-up ratio is defined as 1/n, where n is an integer (10≥n≥1). The mean specific size increases linearly with n at large electron currents. The mean specific size in the case of 1/n(n>1) is larger than that in the case of 1/1 by 15% at the maximum in the range of acceleration voltage used. The Poisson distribution function and the ion current distribution function proposed by Falter et al. give better agreements between the theoretical and experimental values of the mean specific size.
Pulse-Excited Characteristics of Au/ZnSe : Mn/n-GaAs Low Threshold Thin Film DC EL Cell
Authors: Ohnishi Hideomi , Hamakawa Yoshihiro
Published: November 2005

Pulse-excited response of the electroluminescence and its concentration dependence of luminescent center have been investigated in order to clarify the electroluminescent mechanism of Au/ZnSe: Mn/n-GaAs heterostructure cell. The best record obtained from ZnSe: Mn phosphor film cell shows 31 mlm/W in luminous efficiency and 230 fL in brightness under the dc excitation condition of 20 V and 10 mA. The relaxation time is estimated from brightness wave forms to be 17.5 µs for Mn-F complex center, while that of Mn2+ ion center varies from 140 to 20 µs with increase of Mn content. The experimental data show that two processes exist of a carrier injection through the interface states and the electron flowing over the heterojunction barrier.
Monte Carlo Calculation on Phosphor Screens with Complicated Boundary Conditions
Authors: Urabe Koichi
Published: November 2005

A new method of calculating the destinations and intensities of luminescent emission in a phosphor screen with complicated boundary conditions is presented. This method traces the rays emitted from individual particles by geometrical optics using Monte Carlo procedures. Model calculations are carried out for the phosphor screen of a color picture tube.
Electrical Conduction of ZnO Varistors under Continuous DC Stress
Authors: Sato Ken , Takada Yoshio , Maekawa Hiroshi , Ototake Masafumi , Tominaga Shotaro
Published: November 2005

The degradation mechanism of I-V curves of ZnO varistors is investigated by means of thermally-stimulated currents and photoconductivity measurements. We postulate that the degradation is due to electrons and holes accumulated across the grain boundary face to face with each other such as polarized charges in a condenser. According to the photoconductivity measurements, the degradation of I-V characteristics is found to be due to the increase in carrier density and field-dependent drift mobility. In addition, the varistor after dc stressing shows n-type conduction.
The conduction mechanism for the initial I-V characteristics is also discussed. A model similar to the mobility-gap model is proposed, and it is suggested that the intrinsic conduction should be taken into account for the Schottky-type conduction mechanism.
Optical Propagation Properties in Gyromagnetic Waveguides Using Faraday Effects of YIG Thin Films on GGG Substrates
Authors: Taki Kazunari , Miyazaki Yasumitsu , Akao Yasuo
Published: November 2005

A theoretical analysis using hybrid modes is presented for gyromagnetic thin film waveguides consisting of YIG crystal films on the GGG substrates, to obtain accurate design data for nonreciprocal circuits of optical isolators. In this hybrid mode method, eigen HE and EH modes which are the exact solutions of electromagnetic fields in garnet films are shown. Expressions for the eigen functions in terms of the dielectric tensor elements with the Faraday effect are derived. To estimate the fundamental propagation properties of optical hybrid waves, propagation constants and wave function profiles for hybrid modes are evaluated in a lossless YIG thin film on the GGG substrate. TE-TM mode conversions through the Faraday effect are evaluated in devices consisting of two isotropic waveguides and one gyromagnetic waveguide with the isotropic exterior substrates of upper cover sides that yield the phase mismatch condition.
InP/GaInAsP Buried Heterostructure Lasers of 1.5 µm Region
Authors: Nagai Haruo , Noguchi Yoshio , Takahei Kenichiro , Toyoshima Yoshio , Iwane Genzo
Published: November 2005

The buried-heterostructure, in which the quaternary active layer is completely surrounded by InP crystal, has been realized in 1.5 µm region by low temperature liquid phase epitaxial growth. Low threshold current of 25 mA under CW operation was achieved at 26°C. This is the lowest value so far reported on the InP/GaInAsP laser in 1.5 µm wavelength region.
Parabolic Behavior of Melting and Boiling Points versus Coulomb Potential in Ionic Substances
Authors: Nakamura Tetsurō , Takagi Yoshiki
Published: November 2005

Melting points and boiling points of alkali fluorides, alkali chlorides, alkali bromides and alkali iodides, have been found to form parabolas as a function of Coulomb energy x=q
2/(r
c+r
a). Melting points versus x for oxides of cations with rare gas-type outer electronic shells have been found to behave similarly. A primary explanation of such parabolic behaviors of melting points versus x is given and a quartic behaviors of enthalpy of fusion versus x for ionic substances which is caused by multipole interactions in ionic liquids is demonstrated.
A Modified Model for the Mechanism of Symmetric Electrochromic Cells
Authors: Morita Hiroshi , Washida Hiroshi
Published: November 2005

The coloration and bleaching kinetics of a symmetric electrochromic cell have been investigated. The current-time response of the symmetric cell is explained by a modified equation concerning space-charge limited current, which includes a term of time-depended voltage. From an experiment using a reference electrode it was found that the voltage change of the cell is due to the generation of electromotive force between an electrochromic layer and an electrolyte and also to the change of potential distribution between two electrochromic layers of the cell.
Properties of Amorphous Si Prepared by RF Sputtering with a High Ar Pressure
Authors: Shimizu Tatsuo , Kumeda Minoru , Watanabe Ichiro , Kiriyama Yoshinari
Published: November 2005

Amorphous Si films prepared under high Ar pressure are oxidized by exposure to air after preparation. In situ measurements show that the main reason for the low electrical conductivity of such films is not due to the oxidization. The film density is lower for the high Ar pressure film than for the low Ar pressure film, but the ESR center density is larger for the latter film. The former film is porous and has a low density of dangling bonds, while the latter film is more densely packed and has a higher density of dangling bonds.
Enhanced Step Coverage of SiO2 Films Sputtered in Hydrogen-Argon Mixed Gas
Authors: Serikawa Tadashi
Published: November 2005

Step coverage of magnetron sputtered SiO2 films prepared in 30% hydrogen-70% argon mixed gases has been investigated in comparison with that in argon only. The following results were obtained. (1) In pure argon, the step coverage profile has a vertical slope with microcrack at the step. (2) By mixing hydrogen in argon, step coverage is improved to a positive slope profile without microcracks, and the film at the step is densified.
Infrared Spectra of Amorphous Silicon-Fluorine Alloys Prepared by Sputtering in Fluorosilane-Argon Gas Mixture
Authors: Shimada Toshikazu , Katayama Yoshifumi , Horigome Shinkichi
Published: November 2005

Infrared spectra of amorphous Si : F alloys prepared by sputtering of a silicon crystal in SiF4 or a mixture of SiF4+Ar were measured in the frequency range of 450–4000 cm-1. Six absorption bands were observed in the 800–1100 cm-1 region. These bands are assigned as the SiF
N
(N=1, 2, 3) bond stretching vibration modes by comparison with the infrared spectra of SiF
N
H4-N
molecules. In addition, fluorine modified or enhanced Si-Si bond stretching modes were observed at 515 and 650 cm-1.
Comments on “High Speed Photoresponse Mechanism of a GaAs-MESFET”
Authors: Gammel J. C. , Ballantyne J. M.
Published: November 2005

It is shown that recent results reported by Sugeta and Mizushima do not contradict the photoconductive model for the OPFET.
Auger Electron Spectroscopy of Cu2S–CdS Heterojunction Interface
Authors: Morimoto Jun
Published: November 2005

The depth distribution profiles of elements near the interface of Cu2S–CdS heterojunction formed on the polar (0001) and (0001̄) surfaces of CdS were investigated by Auger electron spectroscopy. The diffusion of Cu into CdS was found to be easier on the CdS (0001̄) surface than on the (0001) surface. Further, the variation of the chemical shift in the dN(E)/dE Auger signal of S (LMM) is shown to occur between Cu2S and CdS.
Effect of Silver Additive on Frequency-Dependent Conductivity of Amorphous As2Se3
Authors: Kitao Michihiko , Asakura Norio , Yamada Shoji
Published: November 2005

Frequency-dependent conductivity of amorphous As2Se3 containing silver up to 0.5 at% has been measured at room temperature. In the frequency range from 30 Hz to 500 kHz, the ac conductivity σac of undoped As2Se3 depends linearly on the frequency. On the other hand, σac of As2Se3 containing silver is proportional to ω0.7 and this relation holds irrespective of silver content. The quantity of σac increases monotonically with silver content. Silver additives are considered to be directly concerned with the ac conductivity.
Raman Scattering Study on Unoxidized Antimony in Anodic Oxide-Films of InSb
Authors: Nakagawa Tadashi , Ohta Kimihiro , Koshizuka Naoki
Published: November 2005

Raman scattering measurements were carried out to detect antimony in anodic oxide-films of InSb. It was found that no antimony inclusion was present in the as-grown film, in contrast to the case of a thermally oxidized surface. Antimony inclusion was, however, detected for samples which were subjected to annealing for 10 min at temperatures above 260°C after anodization.
Structural and Chemical State Analysis of the Heat-Treated Au/GaSb(110) Interface by Means of Angle-Resolved X-Ray Photoelectron Spectroscopy (ARXPS)
Authors: Koshizaki Naoto , Kudo Masahiro , Owari Masanori , Nihei Yoshimasa , Kamada Hitoshi
Published: November 2005

Angle-resolved X-ray photoelectron spectroscopic (ARXPS) studies were carried out to characterize the Au/GaSb (110) interface. Immediately after the evaporation of gold on the GaSb (110) surface to a thickness of about 85Å, angular distribution curves (ABC's) of photoelectron intensities showed no fine structures. After heat treatment at 540°C for 30 minutes, ADC's for Ga3d, Sb4d and Au4f showed explicit fine structures. Furthermore, the ADC for Au4f was quite similar to that for Ga3d. This seems to indicate that the Au atoms were incorporated into the gallium antimonide lattice and were preferentially substituted for Ga atoms.