bluuebunny/crossref_metadata_2025 huggingface dataset:
Impurity-Dope Effects on the Anelasticity of Graphite
Authors: Tsuzuku Takuro , Saito Mitsuhiro
Published: November 2005

By means of a resonant bar technique, the impurity-dope effects on the anelastic properties of various graphites have been investigated at temperatures ranging from 290°K down to 4.2°K. A pronounced peak in the internal friction vs. temperature diagram for polycrystalline graphite has been found to grow up, with stepwise bromination up to 0.25% Br/C, and to shift toward higher temperature side from the original position around 50°K. Also for the pyrolytic graphite boronated to 0.5 at. % a similar relaxation peak was found around 80°K. As to the background component, an analysis in the framework of the Granato-Lücke theory was examined on the resonant frequency vs. temperature relationship, and has yielded the activation energy values for thermal depinning of dislocations as follows; 0.04 eV and 0.03 eV before and after the bromination respectively, and 0.006 eV for the boronateds. An interpretation of these observations is given, based on the duplex role of impurities in graphite, viz. pinning function and viscous drag effect to dislocations.
Uniaxial Stress Effect on the (000) Valley of As-Doped Ge
Authors: Arizumi Tetsuya , Yoshida Akira , Oozone Takashi
Published: November 2005

The stress dependence of the (000) conduction band minimum (\varGamma2
-) of germanium was investigated at 77°K by the shifts of onset-voltages of the direct tunneling currents in reverse-biased Ge tunnel junctions under large uniform uniaxial stresses. The tunnel junctions were formed by alloying tin dots doped with 0.5% gallium on opposite faces of a germanium rectangular bar, containing the arsenic of about 2×1019 cm-3 concentration. Maximum stress applied along the [111] axis was about 6×109 dyn/cm2. The uniaxial stress coefficient of the (000) conduction valley was found to be (10/3)×10-12 eV cm2/dyn, in good agreement with that of Paul et al., determined by optical measurements on intrinsic germanium under hydrostatic pressure. The stress dependence of the (000) minimum conduction band of germanium may be independent of the impurity concentration.
Experiments on a Far Infrared CN Laser
Authors: Kon Shōzō , Yamanaka Masanobu , Yamamoto Junya , Yoshinaga Hiroshi
Published: November 2005

The characteristics of a CN laser with an external mirror operated with the pulsed or d.c. discharges are described. The maximum laser output power is obtained with a coupling mirror of suitable dimension. The laser can oscillate when a metal mesh is used as a resonator mirror. Data on the laser output vs. gas pressure flow rate, discharge current and discharge energy are given. The oscilloscope trace of the laser output shows that the oscillations occur as a train of spikes produced during the discharge for wide pulses, while, for very narrow current pulses, the oscillations occur in the afterglow period of the discharge and they consist only of a single peak.
Thermomagnetic Effects in the Mixed State of Type II Superconductors
Authors: Ohta Tokio
Published: November 2005

A phenomenological theory is developed for the thermomagnetic effects in the flux flow state of type II superconductors. Ettinghausen-, Nernst-, and Righi-Leduc-coefficients are expressed explicitly with the use of known physical quantities. Thermal conductivity and analogous Peltier coefficient due to flux line are discussed in detail using a quasi-particle model for the flux line. It is shown that the analogous thermoelectric figure of merit in the flux flow states has large values of the order of 1/T in the perpendicular direction to the external electric current, while it is of the order of 10-2/T∼10-3/T in the direction parallel to the current. A possibility of a negative figure of merit is also pointed out.
Improvement of Quantum Efficiency in Gallium Arsenide Electroluminescent Diodes
Authors: Nakano Takao , Fujikawa Kyo-ichiro , Oku Taiji
Published: November 2005

The external quantum efficiency of Sn, Se or Te doped GaAs electroluminescent diodes in the 1×1016 to 1.5×1018/cm3 carrier concentration range was investigated. A maximum luminescence efficiency can be obtained in the 5∼7×17/cm3 range at 300° and 77°K. The effect of carrier concentration on the external quantum efficiency was considered on the basis of a simple assumption. The existence of the maximum efficiency in the 5∼7×1017/cm3 range was clarified from the fact that the external quantum efficiency was determined by the injection ratio of electrons and the bulk absorption for the photons, provided the fraction of electrons injected into the p-type side of the junction which recombined radiatively was not affected by the doping level in the n-type side. The doping effect on the external quantum efficiency was evidently seen for Sn doped diode.
The electroluminescent GaAs diodes of the p
+-n
+-n structure in order to improve the injection ratio and to reduce the bulk absorption. The external quantum efficiency of the p
+-n
+-n structure fabricated with the liquid-phase epitaxy was improved by a factor of 10∼20 in comparison with the usual structure.
Trap Levels in Gallium Arsenide
Authors: Furukawa Yoshitaka
Published: November 2005

The effect of illumination on the capacitance of n- and p-type GaAs Schottky barrier diodes has been measured at 77°K. Capacitance change is observed in the photon energy range of (0.7 eV–1.45 eV) for the n-type diode and in the range of (0.5 eV–1.45 eV) for the p-type diode. This effect is explained in terms of the photoexcitation of traps in the space charge layer. It is found that two different kinds of traps are present in both n- and p-type GaAs, one being located at about 0.7 eV and another at about 0.95 eV, below the conduction band edge. The traps found in the present experiment are probably identical with those found in semi-insulating GaAs crystals.
Effect of Magnetic Field on Density Distribution of Injected Plasma in Semiconductor Rods
Authors: Arizumi Tetsuya , Umeno Masayoshi , Horiba Yasutaka
Published: November 2005

The changes in the density distribution of an injected plasma along a semiconductor rod and the anomalous increase in the terminal voltage in a magnetic field are interpreted in terms of carrier loss which is caused by the piling-up of the plasma at the surface due to the Lorentz force and the surface recombination.
The Effect of Amorphous Surface Layers on Electron Microscope Images of Crystals
Authors: Watanabe Hiroshi
Published: November 2005

By means of an energy selecting electron microscope (H. Watanabe: Japan. J. appl. Phys. 3 (1964) 480), energy analysis was carried out for the electrons forming a special dark-field image, which was obtained by shifting the objective aperture slightly from the optical axis (Y. Kamiya and R. Uyeda: J. Phys. Soc. Japan 16 (1961) 1361). In the no-loss image of aluminum, equal thickness fringes were observed and the intensity averaged over the period was proportional to that in 23 eV loss image which is characteristic to the surface layers. The small angle no-loss scattering by surface layer was concluded to have a major contribution to the no-loss special dark field image, contrasting to the conclusion by Castaing et al. (C.R. Acad. Sci. (Paris), 262 (1966) 1051) that the thermal scattering plays the role.
In case of magnesium oxide a definite conclusion was not derived because of the overlapping of two energy loss peaks characteristic to magnesium oxide and surface layers.
An X-Ray Study on the Structure of the Ternary Au-Cu-Zn Martensite
Authors: Murakami Yuichiro , Nakanishi Norihiko , Kachi Sukeji
Published: November 2005

Crystal structure of the martensite in AuxCu55-xZn45ternary alloys, obtained by quenching the β phase, was investigated by low temperature X-ray techniques. As a result, it was found that the structure varies with the composition and that its diffraction patterns are well accounted for by assuming a monoclinic structure having varying parameters with the composition. For an example, lattice parameters were obtained asa=4.51,b=5.54,c=4.40Å and \angleβ=86.5°for Au 22 at .% alloy. More complicated structure is expected for the alloys containing Au more than 30 at.%. The orthorhombic lattice reported by Duggin & Rachinger could not explain the present results.
Interferometric Measurements of Absolute Stress-Optical Coefficients in Amorphous Polymers I. Direct Determination Method of Absolute Stress-Optical Coefficients, Employing Immersion Technique
Authors: Azuma Kensaku , Soezima Yosio
Published: November 2005

It is known that the usual interferometric method is not convenient for the accurate measurements of “direct” and “transverse” stress-optical coefficients even when the change in thickness of specimen is taken into consideration. This paper describes a method which enables us to measure directly these absolute stress-optical coefficients by immersing the specimen in a liquid whose refractive index is optically matched to that of the specimen. In a case of glassy polymers such as Epoxy and Diallylphthalate, the accuracy of the new method is about 0.1 brewster when refractive index of the immersion liquid is matched to that of the specimen to the order of 10-4. The influence of the thickness change is smaller than the error due to the counting inaccuracy of the shift of interference fringe in a Mach-Zehnder interferometer employed.
Far-Infrared and Submillimeter Maser Oscillators with H2O and D2O
Authors: Minoh Arimichi , Shimizu Tadao , Kobayashi Shunsuke , Shimoda Koichi
Published: November 2005

Construction and operating characteristics of far-infrared masers with water and deuterium oxide are presented. The maser tube is 5 cm in inner diameter with internal mirrors of about 5 m separation. The concave spherical mirrors of 6 cm diameter are used. Under the pulsed excitation of 5∼10 kV with 40 µs duration through the water vapor at about 0.2 Torr, strong maser oscillations are obtained at 47.4, 78.4, 79.1, 118.7, 120.1 and 220 µm wavelengths in H2O, and at 36.4, 72.7, 74.5, 84.3, 107.7 and 171.6 µm in D2O. Output characteristics against the gas pressure, the excitation voltage, and the longitudinal magnetic field are shown. At the optimum operation with the longitudinal magnetic fields peak output powers at 118.7 and 171.6 µm are estimated to be as large as about 3 and 6 W respectively.
Dynamic Mechanical Properties of Polyoxymethylene. II
Authors: Miki Kyosuke , Hikichi Kunio , Kaneko Motozo
Published: November 2005

Real and imaginary parts of complex rigidity of melt-grown polyoxymethylene are measured over a frequency range from 3.0 to 0.01 Hz at various temperatures from -3°C to 138°C by a new torsional pendulum apparatus. Master curves for real and imaginary parts of complex rigidity in the range of α-dispersion are composed by performing a suitable superposition for the dispersion curves. Empirical relation for the time-temperature reduction obtained from the superposition procedures can be theoretically interpreted on the basis of the concept of “smearing-out effect of crystalline field” arising from incoherent lattice vibration in polymer crystals. The apparent activation energy of the α-dispersion evaluated from the temperature dependence of reducing factor is 32 and 25 kcal./mol. in the temperature regions above and below about 95°C respectively. However, it becomes very large in the temperature region below about 40°C.
Piezoelectric Properties and Temperature Dependences of Resonant Frequency of WO3-MnO2-Modified Ceramics of Pb(Zr-Ti)O3
Authors: Banno Hisao , Tsunooka Tsutomu
Published: November 2005

Pb(Zr-Ti)O3 ceramics modified with WO3 show low mechanical quality factor and low coercive field, but ones modified with combination of WO3 and MnO2 show high mechanical quality factor, high coercive field and stable aging characteristics.
Temperature dependence of the resonant frequency is investigated in the wide range of Zr/Ti ratio in the WO3-MnO2-modified ceramics of Pb(Zr-Ti)O3. There are four compositions which are stable in the resonant frequency. In two compositions in the rhombohedral phase, variation in frequency can not be minimized to zero because of an anomaly in the frequency-temperature curve owing to “F
E
1-F
E
2 transition”. One of the rests near the morphotropic phase boundary is slightly shifted to Zr-rich side by heat treatment after the removal of the poling electric field. The last one in the heat treatment after the removal of the poling electric field. The last one in the tetragonal phase has most stable temperature characteristics of the resonant frequency.
An Electron Beam Method of Measuring Resistivity Distribution in Semiconductors
Authors: Munakata Chusuke
Published: November 2005

Resistivity variation in Ge crystals was measured by an electron beam. Resolving power was theoretically analysed. Dimensions of the specimens were 0.4×1×2.1 mm3 (short specimen) and 0.5×1×9.8 mm3 (long specimen), and an ohmic electrode was soldered at each end of the specimens. A pulsed electron beam of 1 kHz irradiated the specimen and an induced voltage of a few ten µV was amplified and integrated to get the resistivity variation. Radius, current and energy of the beam were less than 7 µm, a few nA and 20–30 KeV, respectively. Diffusion lengths were also measured by the electron beam to be 30 µm (shot specimen) and 120 µm (long specimen), and the measured resistivity variation was calibrated by using the diffusion length in each specimen. Calibrated ranges of the resistivity variation of 2.5 Ωcm (short specimen) and 35 Ωcm (long specimen) agreed fairly well with the result obtained by the single-probe method.
Stress in Evaporated Bismuth Films during and after Deposition
Authors: Uozumi Kiyohiko
Published: November 2005

Bismuth was deposited onto thin strips of copper in a vacuum of 2∼5×10-5 torr, and the stress within the films was determined by observing electrically the bending of the strip. Continuous observations of the stress and electrical resistivity of films were simultaneously made during and after the deposition. When a critical thickness d

c
is reached during the deposition, a sharp increase in compressive stress occurs, which precisely corresponds to the appearance of conductivity. The stress in bismuth films after the deposition onto substrates at room temperature is tensile (\lesssim5×107dyn/cm2). Electron micrographs show that films close to d

c
in thickness are in the final channel stage or the hole stage. The origin of the compressive stress during deposition is discussed.
Pulsed X-Ray Radiography with Electron Linear Accelerator (I) Precise Control of Electron Linear Accelerator
Authors: Kanaji Tōru , Yasuda Kyōichirō , Ikuta Shirō , Takeda Michihiko
Published: November 2005

A control method is studied to make an electron linear accelerator radiate accurately the required number of pulses of beam. Counting circuits are used to pre-set the number of pulses. All parts of the accelerator are operated in a fully warmed-up state. A magnetic shutter is placed between the electron gun and acceleration tube to control the radiation. The phase relation between the periodical operation of the accelerator and the starting time of switching is chosen to take away the error caused by the transient state of the shutter. The coincidence of the accelerating field and injected electrons are controlled also to diminish the effect of unexpected radiation due to the leakage of the electrons through the shutter. The experiment shows that the beam radiation is reliably controlled by this method, e.g. the quantity of the electrons included in each pulse is kept constant independently of the required number of the pulses. There is no indication which suggests that the beams radiated are not homogeneous. The intensity of the leakageradiation is small enough and not detected even by an ion-chamber roentgenmeter.
Thermodynamical Analyses and Experiments for the Preparation of Silicon Nitride
Authors: Arizumi Tetsuya , Nishinaga Tatau , Ogawa Hiroshi
Published: November 2005

The vapor growth of silicon nitride film is studied thermodynamically for SiH4-NH3-H2 and SiCl4-NH3-H2 systems. By calculating the partial pressures of gaseous species involved in the reactions, the deposition rates of silicon nitride are determined. The theoretical results for SiH4-NH3-H2 system are compared with the experimental data obtained by Bean et al. and the agreements are found quite good, indicating that an equilibrium or at least a quasi-equilibrium is always established. However for SiCl4-NH3-H2 system the agreements are rather poor, suggesting the deviation from the quasi-equilibrium states or the existence of the complex chemical intermediates etc.
Chemical Deposition of Mo on Si
Authors: Sugano Takuo , Chou Hsun-Kwei , Yoshida Minoru , Nishi Tateki
Published: November 2005

A good Schottky diode has been obtained by the chemical deposition of Mo on Si. Thermodynamical consideration denotes that the deposition rate of Mo is determined by solid MoCl3 produced as the intermediate product of H2 reduction of MoCl5. If the deposition temperature is above 600°C theoretical deposition rates agree with experimental results. Mo deposited on Si at 500∼800°C has the structure of fiber texture oriented to (100). Above 900°C, MoSi2 is detected by electron diffraction analysis. Between 600 and 800°C, the Mo film of thickness 1000 Å has the resistivity which is very close to its bulk resistivity. By the deposition for 30 min. at 560°C, a good Mo-Si Schottky diode with the same barrier height as previously reported, is obtained. At 600°C, the deposition time must be within 15 min. to get a good Schottky diode. But the barrier height is about 20% higher than that of a diode, fabricated at 560°C.
On the Excitation Mechanism of the Thin Film Electroluminescence of ZnS; Cu, Mn, Cl
Authors: Sasaki Keisuke , Kurita Shoichi , Omoto Yoshikazu
Published: November 2005

Thin film of ZnS; Cu, Mn, Cl prepared by direct vacuum evaporation shows an orange-yellow emission when a negative pulse voltage is impressed on the aluminium electrode. The relation between the impressed voltage V and the emission intensity B deviates evidently from the well-known formula ln
B
1/√V if the range of the voltage is wide. On the basis of the measured V-I characteristics and the observed current waveform, it is apparent that electron avalanche takes place due to collision ionization in the thin film. From this point of view, supposing the model that electron avalanche by collision ionization takes place inside the so-called Schottky barrier of the Al-ZnS contact and these electrons excite Mn luminescent centers, a calculated curve is obtained with a simple model and this agreed very closely with the typical experimental data of the emission characteristics.
Negative Resistance and Relaxation Effect of Conductivity in Photoconductive CdS at Low Temperature
Authors: Yamamoto Keiichi , Niu Hirohiko , Abe Kenji
Published: November 2005

Negative resistance phenomena are observed in CdS single crystal at temperatures below 222°K and at conductivities larger than 10-3(\varOmega cm)-1. We are interested here in the change of conductivity σ(t) after sudden removal of the high electric field which caused the negative resistance. The relaxation time of conductivity is very long ranging from a few seconds to several tens seconds and varying linearly with the inverse of conductivity. The relaxation time versus 1/Tcurve has a kink point at 222°K; this temperature coincides with the critical temperature below which the negative resistance can be observed. From measurements of the spatial distribution of relaxation time and electric field it is found that the negative resistance is not caused by the inhomogeneity but by the decrease of the number of carriers in the sample.
Theoretical Interpretation of Dose and Dose-Rate Dependences of Thermoluminescent Dosimeter
Authors: Shiragai Akihiro
Published: November 2005

The properties of thermoluminescent dosimeter are investigated by the theoretical interpretation of the radiothermoluminescent phenomenon of the phosphors. The radiothermoluminescence is interpreted more inclusively if the creation of thermoluminescent traps by irradiation and the fading during irradiation are taken into account. The dependences of the thermoluminescence light sum (the response of thermoluminescent dosimeter) on dose, dose rate and irradiation time is qualitatively described by the first order kinetics model of monoenergetic electron traps. The two examples are discussed. The conclusions deduced from the model are found to be in good agreement with the experimental results.
Isochronous Cyclotron with Axially-Symmetric Electric and Magnetic Fields
Authors: Takeda Tatsuoki , Arikawa Tatsuo
Published: November 2005

An electron model of an axially-symmetric isochronous cyclotron was constructed and the beam properties were investigated for the purpose of studying, experimentally, an accelerator using electric and magnetic fields in combination as a guide field. As a model cyclotron of those which accelerate proton beams up to ∼100 MeV, a maximum energy of electrons of 50 KeV (γ\cong1.1) was chosen. The isochronous field of the cyclotron was composed of electric and magnetic fields–the electric field having a radial component and the magnetic field having an axial component on the median plane. The electric field was produced by concentrically devided electrodes set on the inside walls of the dees; the magnetic field was produced by using a pair of air-core coils. Electron beams were accelerated up to almost maximum energy. The behavior of the electron beam was in good agreement with computer calculations.
An Accurate Measurement of the Mercury Vapour Drag Effect in the Pressure Region of Transition Flow
Authors: Nakayama Katsuya
Published: November 2005

The pressure differences caused by the mercury vapour stream from a source to a trap have accurately been measured with a diaphragm gauge. The measurements have been made for nitrogen, krypton, and xenon at a temperature of 28.0±0.1°C in the pressure range from 10-3 to 10-1 Torr. All the data obtained have been found to fall well on a curve predicted with a proper value of parameter peculiar to a given system. It has experimentally been assured that the sufficient prediction is possible to make on the relative errors in low pressure measurements with McLeod gauges if proper values on the molecular parameters are available. Diffusion constants deduced from the experimental data are in good agreement with the theoretical expected values.
A Multipurpose High Pressure Microbomb
Authors: Carmichael R. S. , Sawaoka Akira , Kawai Naoto
Published: November 2005

A convenient, portable pressure microbomb has been designed for use with any uniaxial press. The present model provides for the application of a hydrostatic pressure up to 11 kb, and a uniaxial compression dependent on the force of the press. Both pressures may be applied simultaneously, and can be varied independently for controlled plastic deformation of a sample. The pressure vessel is constructed of a hardened non-ferromagnetic alloy, which allows measurement of changes of magnetic properties during deformation. Experiments may be conducted from liquid helium temperature to 200°C. A desired pressure condition can be maintained in the microbomb by locking, enabling measurements to be performed on apparatus other than the press, or after a time delay.
Inhomogeneity in Refractive Index of Evaporated MgF2 Film
Authors: Nagata Ken-ichi
Published: November 2005

By the use of a zero-order approximate formula for reflectance the thickness and inhomogeneity of a transparent film can be determined from angles of incidence for minimum reflectance measured for different wavelengths with p-polarized light. The method was applied to evaporated MgF2 films. The results are as follows. Up to thicknesses of about 1200 Å, the films are homogeneous. For thicknesses from 1300 to 2200 Å, the difference between the refractive indices at the front and rear surfaces of film is less than 0.002, and is undetermined. For thicknesses from 2300 to 6100 Å, the difference is measured as 0.003∼0.034 and increases linearly with film thickness. The refractive index at the front surface of film is larger than at the rear one. The inhomogeneity begins increasing at about 2300 Å.
The Aging Characteristics in Perovskite-Type Ferroelectric Ceramics
Authors: Uchida Naoya , Ikeda Takuro
Published: November 2005

The aging characteristics of the physical constants have been studied under various biasing and temperature conditions for the ceramics of BaTiO3 and Pb(Zr-Ti)O3 system. The change of the dielectric constant is assumed to be divided into two parts: one is the increase due to the 90°-back-rotation of domains in connection with the dielectric anisotropy and the other is the decrease mainly due to the 180°-back-reversal in relation to the domain clamping effect. The aging of the dielectric constant has been calculated under the above assumption using the measured values of electrostriction and polarization. The calculated values agree well with the observed ones both in BaTiO3 and Pb(Zr-Ti)O3 families ceramics, and the aging characteristics can be explained by the present treatment. The aging rate of the dielectric constant does not increase monotonically with temperature for unpoled Pb(Zr-Ti)O3 families ceramics, and suggests that in this case aging cannot be interpreted with a simple thermally activated process.
The Effects of Traps in the Semiconductor on the Characteristics of MOS Transistors
Authors: Iwauchi Shigeki , Tanaka Toshio
Published: November 2005

The influences of hypothetic and real deep lying centers introduced intentionally or not in the semiconductor on the characteristics of MOS transistors are formulated and are numerically computed for silicon silicon-dioxide structures, on the assumption that the centers are distributed uniformly and the mobility of carriers in the channel is constant and independent of the existence of the centers. A deterioration or an improvement due to an introduction of the centers, depending on the position of levels associated with the center in the forbidden gap and the values of their capture cross sections for electrons and holes, is resulted.
Stable Strain-Induced Magnetic Remanence in Nickel, Cobalt, and Magnetite
Authors: Carmichael R. S.
Published: November 2005

Three magnetic materials have been deformed at room temperature, and stability aspects of their magnetomechanical behaviour examined. Plastic deformation of nickel and cobalt, and elastic deformation of magnetite, give a strain induced moment. The remanence is larger and much more relatively stable than isothermal remanent magnetization (IRM) from the field applied during deformation. It is also more stable than an IRM with an equal magnitude, and can have a significantly different microscopic coercivity spectrum. The results are consistent with a model for magnetomechanical effects based on the response to changes in the physical structure.
Influence of the Air-Gap on Surface Density Gauge
Authors: Uemura Teiji
Published: November 2005

The calculations for the single scattering of gamma-rays were made on the case where the surface density gauge was apart from the material surface. Conditions in which the relative error in density caused by the presence of the air-gap was small were inferred from the calculations by assuming several geometrical factors.
From these calculations and experiments, it was evidently seen that the relative error was small in the cases where the solid angle of the incidence of gamma rays was small and where the separation distance between the source and the detector was enlarged. If the separations expressed in the mean free path for the different source energies were kept to be equal, the relative error was also small in the case of the high energy source.
The measurements of wet densities were made on the rammed soils of two types by using a gauge of the backscatter type, compared with one of the transmission type.
Determination of Thermal Diffusivity by the Temperature Wave Method
Authors: Tomokiyo Akihisa , Okada Toshihiro
Published: November 2005

An analysis has been made on the Angstrom's method to determine the thermal diffusivity of solids when the size of the specimens are comparatively small. The equation of thermal conduction was solved under boundary conditions that the temperature was varied sinusoidally at one end of the specimen and was constant at the other end connected to a heat sink. The solution shows that there exist temperature waves propagating along the specimen, attenuating gradually, and being vanished completely at the end connected to the sink. Expressions to determine the thermal diffusivity by measuring the attenuation or the phase difference of the waves at two positions along the specimen have been derived. An apparatus to determine the thermal diffusivity of N-type germanium has been measured at room temperature. The experimental results showed a good agreement with those computed numerically using the present analysis.
Impurity Transfer in GaAs Vapor Growth and Carrier-Concentration Profiles of the Grown Films
Authors: Hasegawa Fumio , Saito Takeshi
Published: November 2005

Doped and undoped GaAs films have been grown epitaxially on semi-insulating or heavily doped n-type (100) plane substrates by the AsCl3/H2 vapor transport method. Doped GaAs single crystals were used as source materials for doped films, and Ga source was used for undoped films. The carrier-concentration of films grown from Te-doped source material varies from 2 to 11 times that of the source GaAs, depending on the growth condition. The carrier-concentration of the films grown from Sn-doped source material agrees with that of the source GaAs, without depending on the temperature difference between the source and substrate. Ge is doped into films as donors, but Si is not doped at all.
The carrier-concentration profiles of the films grown on heavily Te or S-doped substrates are strongly affected by autodoping from the substrates. While in the case of Si or Sn-doped substrates autodoping is not observed.
Confinement of Plasma in a Magnetic Cusp Field Combined with an Electrostatic Field
Authors: Sugisaki Kiwamu
Published: November 2005

The confinement of a plasma in a magnetic cusp field combined with an electrostatic field was studied. Theoretical analysis shows that the cusp loss can be suppressed with the use of an adequate electrostatic field. The macroscopic stability of a plasma in such combined fields was also theoretically examined and it was concluded that there is a region in which the plasma is stable against the interchange instability. An apparatus was constructed and preliminary experiments were carried out. The electric field was successfully applied to the plasma, which rotated around the symmetric axis with a uniform angular velocity. When the electric field of a proper strength was applied, the light emitted from the plasma decayed more slowly than in the case of no electric field. It is conjectured to be due to the reduction of the cusp loss of plasma particles.
Electron-Gamma Angular Correlation Apparatus Using A Si (Li) Detector
Authors: Kawakami Hirokane , Manabe Katsushi , Hisatake Kazuo
Published: November 2005

An electron-gamma angular correlation apparatus was constructed with a Si(Li) detector for electrons and a NaI(T1) detector for gamma rays. Its design and operation are described. The performance was tested with the 1.064 MeV and 0.570 MeV cascade in 207Pb following the decay of 207Bi. The agreement between the test experiment and theory is satisfactory.
An Experimental Study on the Anomalous Transmission of Electrons through Crystals. Measurements with Molybdenite Films at 200 and 500 kV
Authors: Ichimiya Ayahiko
Published: November 2005

Transmitted intensities of electrons I

B
and I

N
were measured at exact Bragg position and at non-Bragg position, respectively. The ratio I

B
/I

N
increased with the thickness at first, had a maximum value (about four) and then decreased with the thickness and approached unity. No anomalous transmission effect was observed for molybdenite films thicker than about 3 µm at 200 kV and 5 µm at 500 kV. This is against the two-beam dynamical theory, where the ratio increases with thicknesses monotonically. The experimental result was analyzed taking into consideration the contribution of electrons which shows no diffraction contrast.
The Mechanism of Photovoltaic Effect of Ge Film Obliquely Deposited in Vacuum
Authors: Takahashi Masaru , Kou Fukuzen , Tada Osamu
Published: November 2005

The investigations were carried out on photovoltaic effects of Ge films vacuum-deposited on glass substrate at an oblique angle of incidence of 45°. By introducing air slowly to the vacuum system the change in photovoltage of the film with the pressure was measured. By illumination through a band-pass filter (0.3µ≤λ≤0.4µ), the photovoltage reversed its sign as the pressure was increased. The sign was changed from negative to positive in case of the illumination from frontside of the substrate, while in case of the illumination from backside, it was changed from positive to negative. The magnitude of the photovoltage increased remarkably in both cases as the pressure approached atmospheric one. On the other hand, when a short-cut filter (0.69µ≤λ) was used, the photovoltages increased with the pressure but their polarities were always positive regardless of the direction of the illumination. Spectral sensitivity of photovoltage in air was also measured. Only in case of the illumination from backside of the substrate, the photovoltage showed negative polarity in the region of wavelength shorter than 0.5µ. These changes in photovoltages with the pressure are ascribed to those of surface recombination velocities of the film due to gas adsorption. The origin of these photovoltages is discussed on the basis of the Dember effect which arises from the difference between electron and hole mobilities.
Effect of Stress on Germanium and Silicon p-n Junctions II. Non-Exhausted Condition
Authors: Kanda Yozo
Published: November 2005

The theory of the stress dependence of the diode current in the exhausted condition, developed previously, is extended to that in the non-exhausted condition. The current changes due to stress are calculated for the main crystallographic orientations by taking into account the changes in the minority carrier concentrations and in the minority carrier mobilities. The changes in the minority carrier concentrations are calculated by taking into account the shifts in the shallow impurity levels.
The results of the exhausted condition are also valid in the non-exhausted condition at room temperature. At lower temperatures, in general, the stress dependence of the minority electron concentration n

p
overcomes that of the minority hole concentration p

n
. In Si, the stress dependence of the diode current of the diode in which n

p
is much greater than p

n
, is larger than that of the diode in which p

n
is much greater than n

p
.
Effects of Interface States on the Characteristics of MOS Transistors
Authors: Tanaka Toshio , Iwauchi Shigeki
Published: November 2005

The presence of fast interface states gives rise to a reduction of the number of mobile carriers in inversion layer and, therefore, has effects on various characteristics of MOS transistors.
In order to obtain quantitative information on these effects, numerical computations of the characteristics are carried out, as examples, for the cases that the density distribution of the interface states is expressed as N

t
(E

t
)=N
t0δ(E

t
-E

t0); N

t
(E

t
)=N·exp
[-{(E

t
-E

t0)/σ}2] and

N_t(E_t)=N·exp
[-{(E_t-E_t0)/σ}^2]  for  E_t>E_t0,
=N    for E_t≤E_t0,

and the results are plotted for different N

t0, N, E

t0 and σ.
It is pointed out that the mobility obtained in a conventional manner, for example, from the slope of the straight line of the g

D
vs V

G
' curve at V

D
=0 might be not real but only “seeming” due to the influence of the interface states near the band edge.
Threshold Current Density and Power Saturation in Read Diode
Authors: Nishida Katsuhiko
Published: November 2005

In p+-n-ν-n+ silicon diodes, the oscillation characteristics have been examined by varying both the impurity density N

d
and the thickness of the drift region. An empirical relation between the threshold current I
th and the frequency f was I
th=5f
2 A/cm2, which has been verified theoretically. A relation between the current density I
sat, at which the microwave output power is saturated, and f was also obtained experimentally as I
sat=130f A/cm2. This result indicates that the decrease of electron velocity just behind the pulsed conduction current in the drift region is the most probable cause of power saturation. In the diode having a fixed drift length, since a higher N

d
allows a larger I
sat, a higer output power could result when the N

d
was higher. The maximum pulse power of 5W at 8 GHz was obtained when the ratio of the avalanche length to the drift length was approximately 10∼20%.
Evaluation of Transient Luminescent Phenomena by Frequency Characteristics
Authors: Doi Kunio , Toshinai Akio
Published: November 2005

The concept of a frequency characteristic is introduced to evaluate the persistence of the luminescent materials. The frequency characteristic is defined as a Fourier transform of a corresponding emission intensity of a phosphor under an impulsive excitation. The frequency characteristics of a monomolecular process, a bimolecular process, and an exponentially build up and decay process are calculated theoretically. The frequency characteristics of several red-emitting phosphors for color television are measured under cathode-ray excitation. The amplitude transfer function of a calcium tungstate obtained experimentally is compared with a calculated curve, and good agreement is obtained. The frequency characteristics from a television system to a visual system are discussed for evaluating the temporal image reproduction property of the phosphor.
A CO2 Q-Switched Laser and Its Nonlinear Amplification Characteristics
Authors: Ohtsuka Yoshihiro , Tsukamoto Masahide , Masutani Kohji , Yoshinaga Hiroshi
Published: November 2005

There have been observed 95 lines oscillating simultaneously in the 00°1–10°0 and 00°1–02°0 vibrational-rotational bands. The thermalization time among the rotational levels is deduced to be about 10-7 s from the Q-switching time at which the competition among the laser oscillation lines disappears. The peak output power in the pulsed discharge was 5 times as large as that in the d.c. discharge. The giant pulse became markedly narrow when an aperture was introduced into the resonator. Peak amplification by a factor of 10 was accompanied with pulse sharpening by using a multiple reflection amplifiertube. Normal laser oscillation was completely quenched by irradiation of a giant pulse. Two giant pulses closely spaced by 10 to 40 µs were generated using a pair of fixed reflectors at the rear end of the resonator. The lifetime of the lower laser level is estimated from the competitive interaction between the two pulses.
Time Behavior of Pulsed Output, Transverse Mode Pattern and Polarization Characteristics in Far Infrared CN Lasers
Authors: Yamanaka Masanobu , Yoshinaga Hiroshi , Kon Shōzō
Published: November 2005

Experimental results on time behavior of pulsed output, transverse mode pattern, and polarization characteristics of the 311 or 337 µm CN lasers are presented. According to the behavior of the current pulse of discharge in a static gas filling, it is possible to find the conditions where the laser oscillation starts or ceases. The near field pattern of each mode passed through the wirecloth mesh mirror is obtained by sliding a Golay cell behind the mirror, and it is shown that the pattern of mode has usually complex structures and is largely changed when the mirror is tilted. The polarization characteristics of the laser light are determined by anisotropies in the cavity, and the polarization azimuth is changed by inserting an one-dimensional grid into the cavity. The polarization flip is observed by tuning through the line center of 311 and 337 µm, when the electroformed or wirecloth mesh mirror is used.
Phase Transformation and Deformation Processes in Oriented Polyethylene
Authors: Seto Tsuneo , Hara Tetsuhiko , Tanaka Kenzo
Published: November 2005

Plastic deformation processes in oriented polyethylene are investigated by the X-ray method, and changes in texture produced by transverse compression are interpreted in terms of twinning, slip and phase transformation. The crystal structure of the new form produced by the phase transformation is determined, and the unit cell is a monoclinic one with a=8.09, b=2.53, c=4.79 Å and β=107.9°. The phase transformation is considered to be of diffusion-less type and a transition mechanism similar to that of twinning is proposed.
Study of Luminous Flow ahead of Cylinder Using an Electric Shock Tube with a Diaphragm
Authors: Matsuzaki Ri'ichi
Published: November 2005

This report describes the experimental study of luminous flow region ahead of cylinder in high temperature and low density flow generated in an electric shock tube with a diaphragm. It is confirmed that a uniform flow is established in this shock tube and this flow is used in the present experiment. Luminous flow region ahead of cylinder is observed from time-integrated photograph. In order to investigate the thickness and the profile of the luminous flow region, microphotometric tracing is performed along the forward stagnation streamline. Relative thickness of the luminous flow region (properly defined thickness of the luminous flow region devided by the body diameter) is not constant but increases with the decrease in the body diameter. This effect seems to be the effect of rarefaction of the flow generated in the present shock tube.
Effect of the Cell Membrane on Mechanical Properties of Flexible Polyurethane Foams
Authors: Suminokura Toshihiko , Sasaki Toshiro , Aoki Nobuaki
Published: November 2005

The effect of cell membrane on the mechanical properties of the foam was investigated. Young's modulus, flow resistance and density were measured for foams with and without membrane. Results show that the membrane in the foam has a reinforcing effect on the cell structure.
The effect of air in the foam on dynamic mechanical properties was studied by comparing the mechanical loss (or tan
δ) in air and in vacuum. The results show that tan
δ in air is greater than that in vacuum and the increment depends on frequency, size and flow resistance of the specimen.
Inhomogeneity Effects on the Oscillation Characteristics of “Long” Gunn Effect Devices
Authors: Hayashi Toshiya
Published: November 2005

The effects of various parameters on the oscillation characteristics of “long” Gunn effect oscillators (from 0.2 to 2 mm) have been investigated under various controllable conditions. Almost all the samples prepared in this experiment showed the typical current-voltage characteristics of Gunn effect oscillators and clean coherent oscillations. Among the many samples tested, irregular ones were found; some did not oscillate coherently and some showed irregular current waveforms. These irregular oscillation characteristics were investigated using the samples with various inhomogeneities applied intentionally. The results of various investigations revealed that almost all irregular characteristics could be explained by the effects of various inhomogeneities in the samples. Namely, localized high conductive regions on the sample surface usually cause current waveforms of irregular shape, which has a number of “humps” between the well-known” spikes of Gunn-Effect oscillations. The location and number of the humps are well correlated with those of the high conductivity regions. High conductivity regions in the bulk also distort the current waveform. Mechanically damaged regions on the sample surface and in the bulk cause distorted current wave-forms and degrade coherency of oscillations. Strong aging effects have been seen in many irregular samples with various inhomogeneities.
Information Capacity of Radiographic Images
Authors: Kanamori Hitoshi
Published: November 2005

The maximum entropy i.e. information capacity of radiographic images is given from the information theory. New concept in treating upon the signal and the quantum noise are introduced. Information capacity is roughly proportional to the square band-width at low bandwidth, whereas it saturates at high bandwidth. This bandwidth is the lowest cutoff frequency in optical transfer functions of elements in a image transfer system taking into consideration. Examples are given for a typical X-ray radiographic system.
Effects of Specimen Thickness and Orientation on Increase in Weight of Copper Single Crystals due to Heating in Zinc Vapor
Authors: Yamaguchi Hiroyuki
Published: November 2005

Copper single crystals whose surfaces were parallel to {100}, {111} or {112} planes were heated at various temperatures in zinc vapor and effects of specimen thickness and orientation on the increase in weight by heating were studied. The apparent activation energies for zinc diffusion in copper calculated from the weight increase are affected by specimen thickness and orientation. Their values for {112} specimens of 0.25, 0.65 and 1.20 mm in thickness are 1.68, 1.69 and 1.70 eV, respectively, whereas those for the {100} and {111} specimens of 1.20 mm in thickness are 1.68 and 1.70 eV, respectively. An explanation of these differences is given in terms of the variation of the formation energy of a vacancy with stress caused by zinc diffusion.
Velocity of Shock Waves in Crossed Electromagnetic Fields
Authors: Uchida Motokazu
Published: November 2005

The velocity variations of shock waves in steady, crossed electromagnetic fields have been measured by using a T-shaped electromagnetically driven shock tube filled with helium at an initial pressure of 1 Torr. Also the analysis concerning the velocity variations are made by the characteristic method including the electrical conductivity variation due to the change of the shock wave velocity and assuming that the magnetic Reynolds number is very small and that the Hall effect is negligible. The effect of finite magnetic Reynolds number on the velocity variation is estimated analytically. The effect is shown to be small. The measured variations of the velocity agree fairly well with those obtained analytically.
Electron Energy Analysis by a Cylindrical Magnetic Lens
Authors: Ichinokawa Takeo
Published: November 2005

Cylindrical magnetic lenses were developed with the aim of energy analysis of electrons. A set magnetic pole-pieces with rectangular apertures was inserted into the bore of the intermediate lens of a usual electron microscope and was used as an analyzer lens. It has a large chromatic aberration constant for off-axial rays when it was energized to a lens strength k≃√3. An image of specimen was formed by the objective lens on a slit plane of the field limiting aperture. The energy of electrons which had passed through the slit was analyzed by the analyzer lens and the energy loss spectrum of the limited image was obtained perendicularly to the slit length with an energy resolution of 1 eV at 80 kV.
Lens action of the analyzer lens and experimental procedures for energy analysis are described in details. Some results of energy analysis are shown for several specimens of various thicknesses. The energy resolution and position resolution of this analyzer are discussed for a few practical cases.