bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Shielding by Superconducting Y-Ba-Cu-O Prepared by the Modified Quench and Melt Growth (QMG) Process
Authors: Sasaki Tsutomu , Tanaka Masamoto , Morita Mitsuru , Katsuyoshi Miyamoto Katsuyoshi Miyamoto , Misao Hashimoto Misao Hashimoto
Published: February 2005

Magnetic shielding capability has been investigated on Y-Ba-Cu-O crystals prepared by the modified quench and melt growth (QMG) process at 77 K and 4.2 K. Overall critical current densities in large single-grained specimens were estimated to be about 104 A/cm2 based on the Bean model in order to predict shield effect. At 77 K, a single grain cylinder shields the inside up to about 0.2 T of the external field, and this value is the highest among all the values reported so far for tubes fabricated of oxide superconductors. A comparison between shielding characteristics of a single grain and those of a polygrain demonstrated that weaklinking high-angle grain boundaries should be eliminated for high field shielding. Lorentz force, flux creep, and flux jump are discussed.
Effect of Polishing on Time Dependence of Average Substitutional Impurity Concentration in Dissociative and Kick-Out Mechanisms
Authors: Takahashi Manabu , Yoshida Masami Morooka
Published: February 2005

From the standpoint of experimentally distinguishing the dissociative mechanism from the kick-out mechanism, the time dependence of the substitutional impurity concentration in the diffusion is useful. In a dislocation-free sample, the reaction of point defects with sample surfaces is the limiting process, and the impurity concentration may depend on distance from the surface. In the experiment, the surface is polished before the concentration measurement. Therefore it is important to know the effect of amount of polishing on the time dependence of the average substitutional impurity concentration.
In this paper, the effects for both in-diffusion and annealing processes are calculated. It is concluded that, when a dislocation-free sample is used, the effect is strong for both in-diffusion and annealing processes in terms of the dissociative mechanism and for the annealing process in terms of the kick-out mechanism.
Mechanical Transfer Function of a Pendulum Suspended with a Finite-Mass Wire
Authors: Norikatsu Mio Norikatsu Mio
Published: February 2005

In free-mass gravitational wave detectors, pendulum suspension is one of the most important parts. In this report, the mechanical transfer functions are calculated for the pendulum comprised of a wire of uniform density and a point mass attached to the end of the wire, and their characteristics are discussed in terms of the normal-mode expansion method.
Formation of Microcraters by Bombardment of Microclusters
Authors: Katakuse Itsuo , Baba Shun'ichi , Ichihara Toshio , Ikeya Motoji
Published: February 2005

Nanometer-size impact microcraters similar in shape to the submicron craters on lunar samples have been produced on a graphite surface by the bombardment of energetic microclusters of CsI and Au, and have been observed by a scanning tunneling microscope. The dependence of the crater diameter on the mass and energy of the projectiles is within the range of the extrapolated line obtained from massive projectiles. Impact craters generated on a plastic track detector can also be optically detected with enlargement by chemical etching.
Hole Injection from Schottky Gate in Ion-Implanted GaAs Integrated Circuits
Authors: Dima D. Shulman Dima D. Shulman , Lawrence Young Lawrence Young
Published: February 2005

Measurements of currents for a GaAs metal-semiconductor field-effect transistor (MESFET) when a negative bias was applied to a nearby ohmic contact (sidegate) showed that significant hole injection from the gate occurs for large negative sidegate voltages. This is in agreement with a proposed model, in which the presence of an inversion layer under the Schottky gate due to the pinning of the Fermi level at the channel surface causes hole injection into the channel when the gate is positively biased with respect to the sidegate. Upon increasing negative sidegate voltage the substrate-channel depletion region is expanded, and consequently, the neutral region of the channel is shrunk. This results in more holes being injected into the substrate from the gate.
On Threshold Selection Using Fuzzy Risk Criterion
Authors: Cheng Ning Fang
Published: February 2005

A parametric and unsupervised method of automatic threshold selection for image segmentation is presented. An optimal threshold is selected by the fuzzy risk criterion, namely, so as to separate a given picture into meaningful gray level classes under the assumption of object and pixel gray level values being normally distributed. The effectiveness of the proposed approach is illustrated using some experimental images with 256 gray-levels, and the results are compared with minimum error thresholding method using the criterion functions such as uniformity, shape, and edge measures.
Ar Ion-Beam Etching of Gadolinium-Gallium Garnet
Authors: Katoh Yujiro , Sugimoto Naoto , Akiyuki Tate Akiyuki Tate , Atsushi Shibukawa Atsushi Shibukawa
Published: February 2005

An argon ion-beam etching technique is used to process a Gd3Ga5O12 substrate. A double-layered mask consisting of a Ta film and a photoresist shows good tolerance for the Ar-ion beam during etching. An etching depth sufficient for preparing waveguides is obtained.
Layer Tilt Angle of Chevron Structure in Surface-Stabilized Ferroelectric Liquid Crystals
Authors: IToh Nobuyuki , Narutaki Yozo , Shinomiya Tokihiko , Koden Mitsuhiro , Shuji Miyoshi Shuji Miyoshi , Tomio Wada Tomio Wada
Published: February 2005

Smectic layer structures of some surface-stabilized ferroelectric liquid crystal cells were studied using high-resolution X-ray analysis. The cells were constructed of two glass plates coated with a polymer aligning film rubbed in parallel and exhibited a typical chevron layer structure. The correlation between the layer tilt angle and the molecular tilt angle was investigated in detail, taking into account the differences between the molecular tilt and apparent tilt angles. It was confirmed that the layer tilt angle correlated with the molecular tilt angle though it was slightly smaller, and the ratio of the layer tilt angle to the molecular tilt angle gradually decreased as the molecular tilt angle increased.
The W Values and Fano Factors in Helium and Argon-Doped Helium
Authors: Ishida Nobumiti , Jun Kikuchi Jun Kikuchi , Tadayoshi Doke Tadayoshi Doke
Published: February 2005

The W values and Fano factors for 5.3 MeV alpha-particles have been measured with a gridded ionization chamber and are found to be 43.3±0.3 eV and 28.9±0.2 eV, and 0.24±0.02 and 0.11±0.02 for pure helium and helium+argon (1%), respectively. The W values for both gases agree fairly well with theoretical estimates as well as with previous experimental results and especially with the results of Jesse. The corresponding Fano factors, however, are significantly large compared with those theoretically calculated for the case of electron incidence. The reasons for this difference are discussed.
Plasma Cleaning by Use of Hollow-Cathode Discharge in a CHF3-SiO2 Dry-Etching System
Authors: Seiichi Watanabe Seiichi Watanabe
Published: February 2005

Plasma cleaning by use of hollow-cathode discharge, where RF voltage was supplied with the same phase on both electrodes, was investigated in a CHF3-SiO2 parallel-plate-type dry-etching system. The plasma cleaning by use of the hollow-cathode discharge has achieved a high plasma-cleaning rate, because the electrons were confined by the opposite ion sheaths' electric field and high-density plasma was generated between the electrodes. With the heating of the reaction chamber wall, the plasma-cleaning rate was increased and the deposition rate of the plasma-polymer was decreased. The temperature of the reaction chamber wall was found to be one of the important parameters affecting the etching characteristics, such as the SiO2/poly-Si selectivity.
Isotope Effect of High-Energy Boron Implantation in Silicon by Simulation
Authors: Demetre E. Tsatis Demetre E. Tsatis
Published: February 2005

The range profile of the most abundant stable boron isotope, 11B, implanted into three wafers made of the three stable silicon isotopes, 28Si, 29Si and 30Si, in the energy range between 0.4 to 2.0 MeV, has been studied by the Monte Carlo program TRIM. It is found that the implantation profile depends strongly on the isotopic state of the silicon wafer. Also, it is concluded that the presence of the least abundant stable silicon isotope, 30Si, in a silicon wafer of natural abundance, influences the shallow tail of the implantation profile.
Long-Term Photocurrent Decay in Amorphous As2Se3 Doped with Ag and Cu
Authors: Satoh Kenji , Yamanashi Yasushi , Michihiko Kitao Michihiko Kitao , Shoji Yamada Shoji Yamada
Published: February 2005

Long-term photocurrent decays have been investigated on glassy samples of As2Se3 containing silver or copper up to 1.5 at.%. A pronounced decrease in photocurrent is observed with the addition of impurities up to 0.1 at.%. Photocurrent decay characteristics for all the samples examined are well represented by the extended exponential curve, which can be derived under the assumption of dispersive transport. Activation energy of transient photocurrent decreases with the addition of silver and copper. Recombination rate increases with impurity content in a low-concentration range. Recombination centers are considered to be created by the addition of impurities. In the case of copper, the recombination rate tends to decrease in the concentration range above 0.1 at.%.
ON State Characteristics of Switched Sample of Methyltriphenylarsonium-(TCNQ)2
Authors: T. Ravindran T. Ravindran , S. V. Subramanyam S. V. Subramanyam
Published: February 2005

The temperature dependence of electrical conductivity of ON state of the charge transfer complex methyltriphenylarsonium-(TCNQ)2 shows the characteristics of an amorphous material in the temperature range of 10 K to 236 K. The low resistance (∼1 Ω) of ON state of the sample is due to the field induced structural phase transition from high resistance (∼103 Ω) OFF state at a field of ∼2.5×105 V/m under pressure at a temperature of 300 K. In the hopping regime of the ON state both negative and positive magnetoresistance is observed at temperatures of 11 and 32 K.
Two-Dimensional Kerr Electrooptic Measurement of Nonuniform Electric Fields by CT Method
Authors: Ihori Haruo , Fujii Masaharu , Nishimoto Sakae , Isamu Kitani Isamu Kitani , Kiyomitsu Arii Kiyomitsu Arii
Published: February 2005

It is very difficult to measure nonuniform electric field distributions in insulators. The optical measurements of the electric field were investigated in nitrobenzene using the Kerr effect. A sphere-to-sphere electrode or a sphere-to-plane electrode system was used to produce the nonuniform electric field. A rectangular test cell was made of teflon with two glass windows. A He-Ne laser was used for a light source. The intensity of the light transmitted through the cell was measured with a photodiode. The two-dimensional electric field distribution expressed in absolute value was reconstructed by the computed tomography (CT) method. The measured electric fields were compared with the theoretical one and good agreement was obtained.
Generation and Focusing of Intense Ion Beams with an Inverse Pinch Ion Diode
Authors: Hashimoto Yoshiyuki , Sato Morihiko , Mitsuyasu Yatsuzuka Mitsuyasu Yatsuzuka , Sadao Nobuhara Sadao Nobuhara
Published: February 2005

Generation and focusing of ion beams using an inverse pinch ion diode with a flat anode has been studied. The ion beams generated with the inverse pinch ion diode were found to be focused at 120 mm from the anode by the electrostatic field in the diode. The energy and maximum current density of the ion beams were 180 keV and 420 A/cm2, respectively. The focusing angle of the ion beams was 4.3°. The beam brightness was estimated to be 1.3 GW/cm2·rad2. The focusing distance of the ion beams was found to be controllable by changing the diameters of the anode and cathode.
One-Dimensional Modeling for Magneto-Microwave Plasma Using the Monte Carlo Method
Authors: Ikegawa Masato , Kakehi Yutaka , Kobayashi Junichi
Published: February 2005

This study discusses modeling of a magneto-microwave plasma used in semiconductor manufacturing equipment such as etching reactors and chemical vapor deposition (CVD) reactors. A one-dimensional simulation program for magneto-microwave plasma was developed. This combines a Monte Carlo particle plasma model and an electromagnetic wave damping model. With the use of this simulation, a plasma production mechanism with electron cyclotron resonance and electromagnetic wave damping in a partially ionized gas can be analyzed. Typical results of the effect of gas pressure on the plasma distribution in plasma processing equipment are presented.
Experimental Conditions Required to Achieve Low-Power Pulsed-Laser Annealing of Implanted GaAs
Authors: Gianfranco Vitali Gianfranco Vitali
Published: February 2005

The experimental conditions necessary to obtain low-power pulsed-laser annealing (LPPLA) of implanted samples of GaAs are described. Simple theoretical estimates have been used to show that the sample's temperature evolution is such that it does not produce appreciable GaAs decomposition. Particular attention is paid to the spatial distribution of the energy over the laser beam cross section and the optical system used in the experiments. It is also pointed out that below the melting threshold, but above the upper limit of the energy window, within which the LPPLA is obtained, a structural disorder of the material is induced by the laser itself.
Enhancement of Mobility in Pseudomorphic FET's with Up and Down Monolayers
Authors: Goronkin Herb , Shen Jun , Tehrani Saied , Droopad Ravindranath , Maracas George N. , Ron N. Legge Ron N. Legge , X. Theodore Zhu X. Theodore Zhu
Published: February 2005

We have used molecular beam epitaxy (MBE) to grow single molecular layers (monolayers) in quantum wells in order to improve electron transport. The quantum well energy levels, wave functions, and the carrier concentrations are obtained by self-consistently solving the Schrödinger and Poisson equations. Photoluminescence (PL) and Hall measurements confirmed the energy level shifts and the mobility enhancement due to the monolayer insertions.
Microstructure of c-Axis EuBa2Cu3Oy Thin Films Observed with Scanning Electron Microscopy
Authors: Asahi Masayoshi , Ohki Hidefumi Asano
Published: February 2005

The surface microstructure of c-axis EuBa2Cu3O
y
thin films sputtered onto MgO (001) are characterized by high-resolution scanning electron microscopy (SEM). The SEM images of films grown at a substrate temperature T
s of 600°C, which is lower than our optimum T
s (650°C) for c-axis growth, clearly show evidence of growth steps and spirals at the film surface. The heights of growth steps estimated from the tilted views are 4-5 nm, which correspond to 3-4 unit cells of the c-axis.
Measurement Error Induced by Air Gap of Electromagnetic Wave Absorber in the Coaxial Line Method
Authors: Kim Kyung-yong , Kim Wang-sup , Hyung-jin Jung Hyung-jin Jung , Sung-do Jang Sung-do Jang
Published: February 2005

The effect of an air gap between a specimen and a jig on the material constant (permittivity, permeability) and attenuation characteristics of electromagnetic wave absorbers in the coaxial line method was investigated. The presence of an air gap rendered both the measured permittivity and permeability lower than true values, where this tendency was greater in the case of permittivity. An inner gap, as compared to an outer gap, was found to yield a larger difference between measured and true values. The effect of the air gap was measured for Ni0.3Zn0.7Fe2O4, in which the gap was eliminated by metallization with an Ag-paste. The measured characteristics were in good agreement with corrected values of calculations.
Electrical Conductivity Anomaly in Binary Liquid Mixtures near the Critical Point
Authors: Chatterjee Achintya Kr. , Dipen Lahiri Dipen Lahiri , Robin Ghosh Robin Ghosh
Published: February 2005

The electrical conductivity (\acuteσ) of the three binary liquid mixtures (a) CH3OH+CS2, (b) C6H5NO2+C6H14 and (c) C6H5NH2+C6H12 has been determined at various temperatures starting from the one-phase region down to critical temperature (T
c) at 400 kHz. It is observed that the critical exponent θ of the conductivity singularity near T
c has no appreciable dependence upon the operating frequency. Thus any contribution from dielectric dispersion to the electric conductivity is negligible. Therefore it is concluded that there is a singular contribution to the electrical conductivity which is characterised by an exponent Θ=0.72 in binary liquid systems.
Metal-Oxide-Semiconductor Field-Effect-Transistors Possessing Step Functional I-V Curves Caused by the Punch Through between Drain and Inversion Layer of the Gate
Authors: Karasawa Shinji , Yamanouchi Kazuhiko , Tachibana Yukio
Published: February 2005

Through measurements of an Al gate p-channel Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) with a gap between the gate and drain, the behavior of the minority carrier in the depletion layer is clarified. The turn-on drain voltage depends upon the length and the density of impurity on the punch-through area. That is, V
d=-4 V for L
gap=0.5 µm in 3∼5 Ω·cm n-Si wafer and V
d=-3 V for L
gap=2.0 µm in 120∼200 Ω·cm n-Si wafer.
The abrupt step functional I-V curve is revealed under the condition of low gate voltage. There are surface effects by which the higher the gate voltage, the lower the turn-on voltage of the drain becomes. The hole mobility in the depletion layer made from lightly doped <111> wafer abruptly decreases when the temperature is lowered to below 20 K and the turn-on voltage on the step function MOSFET increases remarkably at 4.2 K.
Study of the Crystal Structure of Titanylphthalocyanine by Rietveld Analysis and Intermolecular Energy Minimization Method
Authors: Oka Kozo , Okimasa Okada Okimasa Okada , Katumi Nukada Katumi Nukada
Published: February 2005

Rietveld analysis and intermolecular energy minimization were used to refine the crystal structure parameters of one of the polymorphs of titanylphthalocyanine (TiOPc), which is a highly photosensitive pigment used in electrophotography. The most probable crystal structure is proposed to be a monoclinic unit cell, space group P21/c. The unit cell parameters are a=1.385 nm, b=1.392 nm, c=1.514 nm and β=120.22°. There are four molecules per unit cell.
Temperature Anisotropy Measurement Using Diamagnetic Loop Array
Authors: Katsumata Ryota , Inutake Masaaki , Ichimura Makoto , Hino Noriaki , Onda Hideaki , Katanuma Isao , Hojo Hitoshi , Atsushi Mase Atsushi Mase , Syoichi Miyoshi Syoichi Miyoshi
Published: February 2005

The anisotropy of the ion distribution function in the velocity space is observed in the ion cyclotron range of frequency heating experiments on the tandem mirror GAMMA 10. The anisotropy, defined as T
⊥/T
// (ratio of ion temperatures perpendicular and parallel to the magnetic field line), is evaluated quantitatively using three diamagnetic loops aligned in the direction of the magnetic field line. Depending on the anisotropy and the plasma pressure, fluctuations below the ion cyclotron frequency are excited. In terms of the quantitative estimation of the anisotropy, it is established clear that the parameter region in which the fluctuations are observed agrees well with a theoretically predicted region of the convectively unstable Alfvén ion cyclotron mode.
Low-Temperature Metalorganic Chemical Vapor Deposition of GaAs on Si by Alternate Gas Flow of the Source Materials
Authors: Fujita Kazuhisa , Hiroto Kanao Hiroto Kanao , Yasushi Matsuda Yasushi Matsuda
Published: February 2005

GaAs layers were grown on Si substrates at 450°C by alternating the gas flow of trimethyl gallium and arsine. Raman spectra showed that the intensity of the longitudinal optical phonon peak taken from GaAs was increased by this approach. Furthermore, transmission electron microscopy showed the reduction of the lattice turbulence and many threading dislocations, which were observed in GaAs layers grown on Si without this approach.
Anomalous Photoemission under the Influence of a Charged Substrance in Low-Frequency Parallel-Plates Discharge in N2 Gas
Authors: Suganomata Shinji , Itsuo Ishikawa Itsuo Ishikawa , Junichi Tanaka Junichi Tanaka
Published: February 2005

Emissions at N2 337.1 and N2
+ 391.4 nm lines were observed near a charged-substance-like wafer or film attached to one of two electrodes which was changing from the temporary cathode to the anode under an applied voltage at frequencies from 1 to 20 kHz. The temporal variation of the floating potential was investigated by the relationship of photoemission to the discharge current at pressures from 0.1 to 0.4 Torr.
A Reactive Energy Transducer with Frequency Compensation
Authors: Kusui Shoji , Kogane Minoru , Kiyoshi Sasano Kiyoshi Sasano , Yoshitaka Sakumoto Yoshitaka Sakumoto
Published: February 2005

Recently the saving of energy has become an important consideration in electric power line systems. One method for saving energy is the reduction of reactive energy loss in electric equipment. Therefore, the measurement of reactive energy is becoming increasingly important. The developed reactive energy transducer is composed of a typical 90° RC phase shifter using an operational amplifier, a multiplier and a DC current to pulse frequency converter of which the output pulses are counted for measurement of the reactive energy. Generally, as the output amplitude of the 90° phase shifter varies with the line frequency, this variation must be compensated for in precise measurement. In the developed reactive energy transducer, the variation of the amplitude of the shifter is compensated for by changing the conversion coefficient of the DC current to pulse frequency converter.
Capacitance of a Resonant Tunneling Diode
Authors: Y. Hu Y. Hu , S. P. Stapleton S. P. Stapleton
Published: February 2005

The capacitance of the resonant tunneling diode (RTD) is calculated based on Poisson's equation and the damped resonant tunneling model, where the incoherent electrons in the quantum well are modeled by the hot electron distribution. In the positive differential resistance region, our results are close to those obtained by using the formulas of E. R. Brown, C. D. Parker and T. C. L. G. Sollner, C=S
εε0
/d, with d measuring the total width of the RTD (including the depletion and accumulation regions). However, in the negative differential resistance region, our result is significantly smaller than that derived by using the formulas of Brown, Parker and Sollner due to the contribution of electrons in the quantum well.
TE Scattering from a Conducting Surface Coated with Multilayer Dielectric Material
Authors: Chi-Sen Lin Chi-Sen Lin , Mohammad Tahir Yaqoob Mohammad Tahir Yaqoob
Published: February 2005

A new numerical method is presented to determine the scattered field from a two-dimensional conducting surface coated with one or more dielectric layers of arbitrary thickness for transverse electric polarization of the incident field. A surface conduction current on the inner conducting surface and a volume polarization current in dielectric material is considered. A set of integral equations are developed by applying the boundary conditions at the conducting surface and in dielectric material. These integral equations are solved by means of the method of moments. The scattered field is assumed to originate in these two currents, so the scattered field and the field-related parameters are readily solved. By considering the polarization of the dielectric, the effects of surface wave excitation are automatically included in the solution. An excellent agreement of results with the exact solution is achieved.
The Most Inflammable State of a Lean Hydrocarbon-Air Mixture
Authors: Kunio Terao Kunio Terao , Chihong Liao Chihong Liao
Published: February 2005

We investigated statistically the spontaneous ignition in an n-octane-air mixture with a fuel excess rate leaner than 0.4 behind reflected shock waves in a shock tube. From the histogram of the ignition induction period, the ignition probability, the ignition development period and then, the most inflammable state were examined. The results suggest that the higher the mixture temperature is, the leaner is the mixture of the most inflammable state.
Preparation and Characterization of Nb/MgO/Bi2Sr2CaCu2Ox Junctions Using the Cleavage Planes of a Single-Crystal Superconductor
Authors: Takahashi Kazuhiko , Shimaoka Kazuhiro , Yamano Koji , Usuki Tatsuro , Yorinobu Yoshisato Yorinobu Yoshisato , Shoichi Nakano Shoichi Nakano
Published: February 2005

Nb/MgO/Bi-Sr-Ca-Cu-O junctions using the cleavage planes of Bi2Sr2CaCu2O
x
single crystals have been fabricated using an artificial barrier for the first time. A large step, in the order of several hundred nm on the cleavage plane, proved to be closely related to the anisotropic behavior of tunneling spectroscopy through the surface of a Bi2Sr2CaCu2O
x
single crystal. This effect for the results of quasi-particle tunneling in the Nb/MgO/Bi-Sr-Ca-Cu-O junctions was in good agreement with calculated results for the local density of states in the superconductor/normal-conductor superstructure model.
Heart Stimulation by Time-Varying Magnetic Fields
Authors: Yamaguchi Masuhiro , Andoh Tomio , Goto Tsuneaki , Hosono Akihiko , Kawakami Tadashi , Okumura Fukuichiro , Takenaka Toshifumi , Isao Yamamoto Isao Yamamoto
Published: February 2005

A strong magnetic stimulator adopted for cardiac muscle was constructed with the stored energy of 50 kJ. Pulsed magnetic fields were applied to dog hearts with normal activity from outside of the body. The magnetic stimulus triggered on the T wave of the electrocardiograph caused arrhythmias in the first and second beats after the stimulus. It has been confirmed that this magnetic effect is due to a direct stimulation of cardiac muscle, not to an indirect stimulation on the vagus nerve. The threshold strength was determined for different pulse durations. The obtained strength-duration relationship is comparable to that for the electric stimulation of the dog heart.
Destruction and Recovery of Superconductivity in Bi-Pb-Sr-Ca-Cu-O Synthesized under High Pressure
Authors: Kawahara Nobuaki , Enami Hiroyoshi , Shinohara Toshiyuki , Hoshizaki Hiroki , Koyama Masaki , Matsumuro Akihito , Imura Toru
Published: February 2005

The high-T
c superconductors (Bi, Pb)2Sr2Ca2Cu3O
x
(2223phase) are hot-pressed from the superconducting powder-mixtures under high pressure up to 5.4 GPa. Although the as-pressed sample synthesized under 40 MPa shows superconductivity, the as-pressed sample synthesized under 5.4 GPa does not. The as-pressed sample synthesized under 5.4 GPa consists of a mixture of an unknown phase and the 2223 phase having a longer c-lattice parameter (2223'). Microscopic structures of the pressed samples are examined by high-resolution transmission electron microscopy. In the as-pressed samples, curved c-planes, which are caused by high pressure, are observed. In the 2223' of the as-pressed sample synthesized under 5.4 GPa, the c-planes are particularly heavily distorted. Recovery of the microstructures and superconductivity occurs through annealing.
Mass Spectrometric Measurements of CO2 Laser Discharges with Time Resolution
Authors: Yuan-Liang Lan Yuan-Liang Lan , Tai-Chiung Hsieh Tai-Chiung Hsieh
Published: February 2005

In mass spectrometric measurements, knowledge of the gas dwell time in the glow discharge region has been utilized to time-resolve the variations of CO2 partial pressure in CO2 laser discharges. The measured data are interpreted by a dissociation-reformation scheme of CO2 molecules in the discharge. Rate coefficients that characterize the CO2 equilibrium process are evaluated, and their technical implications are discussed.
Ferroelectric Behavior in Copolymers of Acrylonitrile and Allylcyanide
Authors: Tasaka Shigeru , Tetsuya Nakamura Tetsuya Nakamura , Norihiro Inagaki Norihiro Inagaki
Published: February 2005

Ferroelectric properties for the copolymers of acrylonitrile and allylcyanide were investigated in a temperature range of 20°C to 180°C. The copolymers containing a certain fraction (35 mol%) of allylcyanide showed a dielectric anomaly with the peak due to the structural change of paracrystal around 120°C, which is above the glass transition temperature (90°C). A sharper X-ray diffraction than that of paracrystal of polyacrylonitrile was observed by annealing. Typical electric displacement (D)-electric field (E) hysteresis in ferroelectrics was observed in the copolymer. The remanent polarization and the coercive field at 105°C were about 700 mC/m2 and 25-30 MV/m, respectively.
Hygroscopic Expansion of Polyester Films
Authors: Ouchi Isuke , Hosoi Masahiro , Tomie Takashi
Published: February 2005

The hygroscopic expansion of polyethylene terephthalate (PET) and polyethylene 2,6-naphthalate (PEN) films was measured by use of a thermomechanical analyzer at 30, 40 or 50°C. Their initial weight increase was proportional to the square root of time after exposure to moisture, obeying Fick's law; the hygroscopic expansion with time showed the same relationship. The equilibrium moisture content was 1.0×10-5/% RH for both films; the hygroscopic expansion at equilibrium was also about the same for these films. However, the diffusion constant for moisture in PEN films was 1·6×10-9 cm2/s at 30°C in comparison with 4·8×10-8 for PET, although the activation energies were 45 kJ/mol for PET and 41 for PEN.
Temperature Dependence of Hardness and Expansion in an Icosahedral Al-Pd-Mn Alloy
Authors: Tsai An Pang , Suenaga Hiroshi , Ohmori Mamoru , Yokoyama Yoshihiko , Akihisa Inoue Akihisa Inoue , Tsuyoshi Masumoto Tsuyoshi Masumoto
Published: February 2005

Temperature dependence of hardness and expansion in icosahedral Al72Pd20Mn8 alloy (i-AlPdMn) are examined in comparison with a cubic Al60Pd25Mn15 alloy (c-AlPdMn). The hardness at room temperature is about 780 kg/mm2 for i-AlPdMn, much greater than that for c-AlPdMn of 420 kg/mm2, and decreases to about 200 kg/mm2 at 973 K. The thermal expansion of i-AlPdMn is found to be linear versus temperature and the thermal expansion coefficient is estimated to be ∼14.6×10-6 K-1.
Radiation Defects Produced by Neutron Irradiation in Germanium Single Crystals
Authors: Fukuoka Noboru , Honda Makoto , Atobe Kozo , Yamaji Hiromichi , Okada Mutsutoshi Ide
Published: February 2005

The nature of defects produced in germanium single crystals by neutron irradiation at 25 K was studied by measuring the electrical resistivity. It was found that two levels located at Ec-0.06 eV and Ec-0.13 eV were introduced in an arsenic-doped sample. Electron traps at Ec-0.10 eV were observed in an indium-doped sample. The change in electrical resistivity during irradiation was also studied.
Deposition of SiO2 Thin Films by Reactive Excimer Laser Ablation
Authors: Tsuji Masaharu , Naoki Itoh Naoki Itoh , Yukio Nishimura Yukio Nishimura
Published: February 2005

Deposition of silicon oxide thin films by ArF excimer laser ablation of a Si target in N2O atmosphere has been investigated in the low substrate temperature range of 15-300°C. The deposited films are characterized by ellipsometry and Fourier transform infrared (FT-IR) spectroscopy. The refractive index and film thickness are measured as a function of the deposited position on the Si wafer, the N2O pressure, the laser repetition rate, and the substrate temperature. Uniform stoichiometric SiO2 films are obtained with a maximum deposition rate of ∼60 Å/min (∼0.2 Å/pulse) at a substrate temperature of 15°C, a N2O pressure of 0.1 Torr, and a repetition rate of 5 Hz.
Mössbauer Effect Study of Lattice Vibration of the Interface Layer between the Oxidized Surface and the Metallic Core of Small Iron Particles
Authors: Ichiro Tamura Ichiro Tamura , Mitsuhiko Hayashi Mitsuhiko Hayashi
Published: February 2005

The lattice vibration of the metallic interface layer between the oxidized surface and the metallic core of small iron particles was studied by Mössbauer spectroscopy. From the temperature dependence of the absorption area of the six-line component due to the interface layer, a Debye temperature of 184 K was deduced, indicating a marked softening of lattice vibration. The average thickness of the interface layer was estimated to be of one atomic dimension.
Palladium Thin-Film Resistors for Josephson LSI Circuits
Authors: Nakagawa Hiroshi , Aoyagi Masahiro , Itaru Kurosawa Itaru Kurosawa , Susumu Takada Susumu Takada
Published: February 2005

Palladium thin-film resistors have been systematically investigated for Josephson LSI circuits. It has been found that the sheet resistance of the palladium was strongly affected by the deposition rate. By the introduction of precise control for the deposition rate using an electron-beam gun, the palladium thin-film resistors have been successfully integrated on the chips with a resistance variation of less than ±2% as is required for fabrication runs.
Measurement of SiH2 Densities in an RF-Discharge Silane Plasma Used in the Chemical Vapor Deposition of Hydrogenated Amorphous Silicon Film
Authors: Tachibana Kunihide , Matsui Tatsuru Shirafuji
Published: February 2005

Silylene (SiH2) radicals have been detected by intracavity laser absorption spectroscopy in a parallel plate RF-discharge system used in the chemical vapor deposition of hydrogenated amorphous silicon. By the use of two different calibration methods, an absolute density ranging from 2×108 to 6×109 cm-3 has been obtained as a function of the input RF power and of the partial pressure of SiH4. The flux of SiH2 onto the substrate electrode estimated from the gradient of the spatial distribution is less than 1013 cm-2 s-1. This suggests that its direct contribution to the film deposition is small, although it plays an important role in gas phase reactions.
An Improved Method to Determine Complex Acoustic Impedance Using a Piezoelectric Resonator
Authors: Tozaki Ken-ichi , Kimura Mitsunobu , Itou Naoki Komatsu
Published: February 2005

On the basis of a propagating wave analysis, a simple method of acoustic impedance determination of material deposited on one face of a resonator is presented. In addition, an algorithm to determine the resonant parameters of the resonator from the measured frequency spectrum of the electrical impedance is provided. Using this method with the algorithm, the complex acoustic impedance is given by the electrical impedance measurement. Experimental determination of the complex viscosity of some liquids is presented as an example of the method, and it is found that the minimum detectable viscosity change is, at most, 1%.
Application of Photothermal Vibration to a Diaphragm Manometer in a Medium-Vacuum Region
Authors: Hane Seiki Inaba
Published: February 2005

Application of photothermal vibration to a diaphragm manometer is described. The resonance frequency of the photothermal vibration was measured for a diaphragm to which a differential pressure was applied. Upon increasing pressure from 0.5 to 3×103 Pa, the resonance frequency increased monotonically by 3 kHz, the shift of which was independent of the gas species in the above vacuum region.
Contact Resistance of Several Metals on YBa2Cu3O7-δ
Authors: Katsutoshi Oka Katsutoshi Oka , Takeo Iri Takeo Iri
Published: February 2005

The contact resistance of metal electrodes deposited on high T
c superconductor YBa2Cu3O7-δ (YBCO) ceramics has been studied. Several metals such as Au, Ag, Cu, Pb, Sb and Al were employed. They have very different tendencies for oxidation, which can be measured by the free energy of oxide formation. The lower the free energy of the metal oxide is, the larger the electrode resistivity becomes. The electrode resistivity is defined by the inverse of conductance per unit area of the electrode. It is suggested that the main sources of contact resistance are the formation of an oxide layer on the metal side of the interface and the appearance of an oxygen-deficient layer on the YBCO surface. Using Au, Ag and Cu, for which free energy is high, electrodes of good quality were obtained where the electrode resistivity was less than 10-6 Ω·cm2.
Effects of Ferrite Magnetic Wedges on Running Characteristics of Split-Phase Condenser Motor in Changing Capacities
Authors: Kaga Akio , Katsubumi Tajima Katsubumi Tajima , Yoshihisa Anazawa Yoshihisa Anazawa
Published: February 2005

The split-phase condenser motor is very useful for driving home electric appliances, but it has low efficiency. In other words, since the condenser motor is operated by two magnetic fields constituting positive phase and negative phase sequences, large electric power losses in light loads and oscillative torque are usually produced. In addition to this, the presence of the slot embedding electric conductors disturbs the flux density distribution in the air gap, producing tooth pulsation and higher harmonic losses. In this study, ferrite magnetic materials have been wedged into the stator slot openings of the condenser motor to smooth the pulsative distribution of the flux density in the air gap, and some experiments have been carried out to discuss the effect of the ferrite wedges on the motor characteristics with various running condenser capacities. As a result, the usefulness of the ferrite magnetic wedge has been verified.
Read/Write Characteristics and Micromagnetic Recorded Structure of Co-Alloy Thin Film Media
Authors: Matsuda Yoshibumi , Kazumasa Takagi Kazumasa Takagi , Yoshihiro Shiroishi Yoshihiro Shiroishi
Published: February 2005

Read/write characteristics of C/CoCrPt, C/CoNiPt/Cr and C/CoCrPt/Cr media are investigated in head-to-medium contact conditions. The media with high coercivities greater than 1 kOe have excellent read/write characteristics with isolated-reproduced voltages of 125-200 nVpp/{µm·(m/s)·turn} and half-output-recording densities (D
50) of 84-135 kFCI. The recorded magnetization was investigated using defocus mode Lorentz microscopy, revealing ripple and vortex structures and a transition length of 0.2 to 0.5 µm. Magnetic clusters estimated to be between 0.2 and 0.4 µm, consist of several hundred crystallites and are strongly related to the noise characteristics of the media. A medium with a relatively small coercivity shows a phenomenon similar to `thickness demagnetization loss', due to side-edge-writing.
NMR Study on Compositional Distribution in Sputter-Deposited Co-Ni Thin Films
Authors: Koji Takei Koji Takei , Yasushi Maeda Yasushi Maeda
Published: February 2005

Compositional distribution in sputter-deposited Co-Ni films was measured by using spin echo 59Co NMR. The NMR frequency spectra of Co-Ni films were very similar to those of compositionally homogeneous Co-Ni powdered alloys. A simulation of the NMR spectra indicated that the Co-Ni films were in a compositionally homogeneous state in which the Co and Ni were distributed randomly at the lattice sites.
Spatial Light Modulators Using Super Twisted Nematic Liquid Crystals and Application to Projection Display
Authors: Hirabayashi Katsuhiko , Fukushima Seiji , Ohno Takashi Kurokawa
Published: February 2005

The super twisted nematic liquid crystal is applied to spatial light modulators. This liquid crystal has very steep threshold characteristics. These spatial light modulators work well even if the photoconductive layer is as thin as 1 µm. This is in contrast to conventional ones which require a thick photoconductive layer (>10 µm). Sensitivity is significantly increased (2 µW/cm2 at 50 Hz operation). This spatial light modulator is applied to a projection display. Images of objects illuminated by the fluorescent lamp can be passed through a lens, and large images are projected onto screens.
Observation of Thermally Interferenced Domains in High Density Magnetooptical Recording by Laser Scanning Microscopy
Authors: Kenji Fukuzawa Kenji Fukuzawa , Akinori Watabe Akinori Watabe
Published: February 2005

Submicron-size fluctuations caused by thermal interference in domains are measured by laser scanning microscopy. Successive domains are about 0.1 µm longer and wider than those having no adjacent domains. Observations by laser scanning microscopy clarify that the readback signal fluctuation is caused by domain-size fluctuation.
Particle Size Dependence of Correlation between Plasma Emission Delay Time and Plasma Emission Intensity of Laser Breakdown Induced by a Particle
Authors: Ajiro Taiko , Fujimori Haruo , Tetsuya Matsui Tetsuya Matsui , Shigeru Izumi Shigeru Izumi
Published: February 2005

Plasma emission delay time and plasma emission intensity of laser breakdown induced by a polystyrene particle in water were measured simultaneously. Short plasma emission delay time tended to correspond to high plasma emission intensity, as expected from the spatial and temporal profiles of the laser pulse power density. Particle size dependence of the correlation between the two parameters may serve in the measurement of the particle size.
High-Speed Semiconductor Light Emitters Based on Quantum-Confined Field Effect: Developed Devices and Inclusion of Quantum Microcavities
Authors: Masamichi Yamanishi Masamichi Yamanishi
Published: February 2005

The collective effort of the author's group on the study of AlGaAs quantum-confined field-effect light emitters is outlined, starting from the physics underlying the light emitters. The developed three-terminal light emitters with functions of current injection and field control of luminescent characteristics demonstrate high-speed switchings of emission intensity at room temperature. The scheme for the high-speed switching of spontaneous emissions does not rely on changes in carrier population at all, but purely on effects of the electric fields on the oscillator strengths in quantum-well active layers of the devices pumped with a very low injection current density, ∼10 A/cm2. The response time, ∼300 ps of the spontaneous luminescence intensity for a pulsed input voltage, is observed to be completely free of the recombination lifetime limitation. Alteration of spontaneous emissions through continuous tuning of emission wavelength by electric fields applied to GaAs quantum wells, together with modification of vacuum field fluctuations of photon systems inside one-dimensional microcavities, is elaborated experimentally to further improve the device characteristics such as external efficiency and spatial coherency of light output, of the field-effect light emitters. The result of the alteration of spontaneous emission indicates the possibility of highly efficient and extremely high-speed light emitters, even with the bonus of a novel function, beam steering.
Study on the Crystallographic and Photoluminescent Properties of Cd3InGaS6. II. Photoluminescence
Authors: Ando Shizutoshi , Endo Saburo , Nakanishi Hisayuki , Taizo Irie Taizo Irie
Published: February 2005

Photoluminescence spectra and X-ray powder diffraction were measured for the system Cd
x
InGaS3+x
(1.0≦x≦3.5) in order to clarify the origin of the intense green photoluminescence of Cd3InGaS6, which is a laminated material of CdS and CdInGaS4. It was found that the intensity of the green emission is intimately correlated with the intensity of the X-ray diffraction line at 2θ=26.5° which indicates a criterion of the formation of the laminated structure. The same experiment on the mixed powder of CdS and CdInGaS4 also revealed the same intimate correlation between intensities of the green emission and the X-ray diffraction line at 2θ=26.5°. Heterostructure CdS/CdInGaS4 prepared by chemical vapor deposition was found to show very intense green emission similar to that observed in Cd3InGaS6. A laminated structure model for the intense green emission is proposed. The model was examined by thermoluminescence measurements.
Operating Characteristics of an Optical Filter with a Linearly Periodic Refractive Index Pattern in the Filter Material
Authors: Ojha Sant Prasad , Choudhury Pankaj Kumar , Prasad Khastgir Prasad Khastgir , Onkar Nath Singh Onkar Nath Singh
Published: February 2005

A design for the fabrication of an IR filter by using a linearly periodic refractive index pattern on the macroscopic scale in a suitable material has been proposed. To predict allowed and forbidden bands of wavelengths for the lower modes, a mathematical analysis is presented. Numerical estimates of allowed and forbidden bands are also made. Several parameters controlling the range of operation and region of allowed wavelength bands have been identified. It is being suggested that the technical knowhow used in the manufacturing of optical fibres and integrated optical devices can successfully be employed for the fabrication of these filters.
Domain Reorientation Effects on the Temperature Dependence of Piezoelectric Properties in Pb(Zn1/3Nb2/3)O3-PbTiO3-PbZrO3 Ceramics
Authors: Sung-Kwon Wi Sung-Kwon Wi , Ho-Gi Kim Ho-Gi Kim
Published: February 2005

For the PZN-PT-PZ ceramic system, the difference in the temperature characteristics of piezoelectric properties between the tetragonal phase and the rhombohedral one was studied from the viewpoint of a domain reorientation mechanism. From the measurement of thermal expansion and the change of high-temperature X-ray diffraction patterns for two phases, it is considered that the more stable temperature characteristics of the tetragonal phase than those of rhombohedral one originates from the stable temperature dependence of 90° domain reorientation for the poled tetragonal phase. The temperature dependence of dielectric properties is more influenced by 180° domain reversal for both the tetragonal and rhombohedral phase.
Dynamic Behaviour of Twisted Nematic Liquid Crystals
Authors: Tarumi Kazuaki , Ulrich Finkenzeller Ulrich Finkenzeller , Brigitte Schuler Brigitte Schuler
Published: February 2005

Expressions describing the dynamic behaviour in terms of τon and τoff for twisted nematic structures have been derived through rigorous analysis. The obtained equations are discussed separately for the twisted nematic (TN) and super twisted nematic (STN) cases. Experimentally obtained switching times under various boundary conditions validate the approach. We discuss the results from the liquid crystal substance developer's point of view.
Birefringence Patterns of Nematic Droplets
Authors: Yang Jiandong Ding
Published: February 2005

Birefringence patterns of nematic liquid crystalline droplets are investigated both theoretically and experimentally. Gridding method is developed to calculate optical birefringence patterns of nematic droplets with different director configurations. Series of birefringence patterns of the four typical nematic droplets (radial, bipolar, axial and equatorial) with different orientations of droplets' axes are obtained. By comparing experimental polarizing photographs with theoretical birefringence patterns, the authors find out that only bipolar configuration represents the self-organized structure of nematic droplets in our epoxy-based polymer dispersed liquid crystal (PDLC). It is also pointed out that the very gridding method can be easily extended to deal with other complicated anisotropic entities.
On the Distinction between the Dissociative and Kick-Out Mechanisms for Site Exchange in Silicon
Authors: Yoshida Hajime Kitagawa
Published: February 2005

Two kinds of mechanisms, the dissociative and kick-out mechanisms, have been proposed so far for the site exchange of impurities in silicon. In this paper, the numerical and approximated solutions of the basic equations describing the two mechanisms for nickel in silicon are discussed to examine how the mechanisms can be distinguished by an in-diffusion experiment. It is found that the two mechanisms may not be distinguishable under some conditions if vacancies and self-interstitials coexist.