bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparations of a-Si:H from Higher Silanes (SinH2n+2) with the High Growth Rate
Authors: Ogawa Kyosuke , Shimizu Isamu , Inoue Eiichi
Published: November 2005

Amorphous(a-)Si:H films showing an excellent photoconductive property were prepared by glow discharge of higher silanes (Si
n
H2n+2[n=2–4]) at high growth rate more than 60 A/s. The gaseous mixture of higher silane was prepared by silent glow discharge of SiH4 in an apparatus connected with a glow discharge reactor. The electric conductivity of the a-Si:H prepared from the higher silane by high growth rate can be controlled over a very wide range by substitutional doping with boron or phosphrus.
New Bistable Optical Device Using Semiconductor Laser Diode
Authors: Ogawa Yoh , Ito Hiromasa , Inaba Humio
Published: November 2005

A novel bistable optical device simply consisting of a semiconductor laser diode and a photodetector has been experimentally demonstrated for the first time. We describe the operational principle graphically to explain the observed effects such as hysteresis and differential gain. The development of its monolithically integrated version will lead to a number of fascinating and useful applications.
Anomalous Ag Surface Diffusion in Amorphous Se-Ge/Ag Inorganic Resist
Authors: Funakoshi Nobuhiro , Zembutsu Sakae , Kasai Toshio
Published: November 2005

An anomalous patterning was observed gollowing a double light exposure of Se-Ge/Ag resist. This anomaly is considered to be caused by Ag diffusion from the masked region into the exposed region through an ionic conductive Ag2Se layer. This surface diffusion also explains the edge sharpening effect.
Influences of Mass and Bond Length on the Debye Temperatures of Ionic and Covalent Substances
Authors: Nakamura Tetsurō
Published: November 2005

A survey of the literature demonstrated that the known Debye temperatures of alkali halides form a linear function of 1/√m̄r
0
3 through the origin, where r
0 is the nearest-neighbor distance and m̄ is the averaged mass. The known Debye temperatures of isostructural covalent substances, and especially those of diamond, silicon, germanium and grey tin, fall on a straight line versus 1/√m̄r
0
4 through the origin. The Debye temperatures of the alkali halides and alkaline-earth oxides with the rock salt structure are appropriately evaluated on a simple model from their elastic stiffness constants.
Phase Shift Spectroscopy of Modulated Photocurrent: Its Application to Gold Levels in Crystalline Si
Authors: Oheda Hidetoshi , Okushi Hideyo , Tokumaru Yozo , Tanaka Kazunobu
Published: November 2005

Gold levels in crystalline Si have been studied by measurement of the phase shift of the modulated photocurrent as a function of temperature and modulation frequency. Three peaks were observed in the phase shift spectra as a function of temperature, two of which are identified with Au donor and acceptor levels, being coincident with previously reported data. The phase shift spectroscopy of the modulated photocurrent can be utilized as a new method for detecting trap levels.
High Performance 880 nm (GaAl)As/GaAs Oxide Stripe Lasers with Very Low Degradation Rates at Temperatures up to 120°C
Authors: Wolf H. D. , Mettler K. , Zschauer K.-H.
Published: November 2005

A practical (GaAl)As/GaAs oxide stripe laser has been developed which has i) very low degradation rates (about 10-5 h-1 at 100°C to 120°C heat sink temperature) even at 880 nm, ii) high characteristic temperature (T
0=200 K to 240 K), iii) stable, linear characteristics up to high optical output and temperatures. The high-temperature degradation data at 5 mW per mirror are comparable to those of high-quality (GaAl)As IRED-s.
Photoluminescence Analysis of Impurities in Epitaxial Silicon Crystals
Authors: Tajima Michio , Nomura Masayoshi
Published: November 2005

The photoluminescence (PL) technique has been applied for the first time to the quantitative analysis of shallow impurities incorporated intentionally and unintentionally in silicon epitaxial layers with a thickness of about 3 µm. The PL from the samples is the overlapping of the PL's from the substrate and from the epitaxial layer. The species of impurities incorporated in the epitaxial layer can be definitely identified by the PL analysis. It is demonstrated that the PL intensity ratio of the impurity component for the epitaxial layer to that for the substrate can be used as a measure of the impurity concentration in the epitaxial layer in the range between 1013 and 1016 cm-3.
Molecular Parametrized CNDO Method for Hydrogen Adsorption on LiF Surfaces Compared with ab initio Approach
Authors: Matsumura Keiko , Yamabe Shinichi , Yanagisawa Yasunori , Huzimura Ryoitiro
Published: November 2005

A comparative study on the hydrogen adsorption on LiF surfaces has been made by the use of the molecular parametrized CNDO (MBPCNDO) and ab initio calculations. The bonding parameters of Li···F, Li···H and F···H in the CNDO scheme are modified and the clusters (LiF)9 for (001) surface and (LiF)8 for (110) including the appropriate Madelung potential are used as adsorbents. MBPCNDO reproduces well the shallow non-dissociative potential curves for the adsorption.
Laser Oxidation of GaAs
Authors: Matsuura Makoto , Ishida Makoto , Suzuki Akira , Hara Kunihiko
Published: November 2005

A new oxidation process for forming oxide films on GaAs has been developed. Irradiation of a GaAs wafer with pulsed laser was carried out in an oxygen atmosphere in order to make a thin oxide layer onto a GaAs surface. Results of reflection electron diffraction analysis on the laser-irradiated surface indicate the oxide formation on the GaAs wafer. Auger depth profiles for the laser-irradiated GaAs showed an increase in the gallium-to-arsenic ratio within 500 Å in depth from the surface, while the oxygen concentration decreased monotonically with the distance from the surface.I-Vmeasurements were performed to study the dielectric properties of the oxide layer and the dielectric breakdown was found to occur at about 12 V.
Formation of Stacking Faults in Pure Ice Single Crystals by Cooling
Authors: Hondoh Takeo , Itoh Taizo , Higashi Akira
Published: November 2005

Fault vectors of various stacking faults formed in pure ice single crystals by cooling were determined from combinations of X-ray diffraction topographs taken with various diffracting planes. It was found that the formation of stacking faults is accompanied by the dissociation of perfect dislocations with Burgers vector b= a+ c. The concentration of excess self-interstitials which precipitated to form faulted dislocation loops during cooling by several tens of degrees was estimated to be 1016 cm-3 from the density of loops observed. Such a concentration of point defects in ice crystals, higher than previous estimates, casts a new light on the understanding of structure-sensitive properties of ice.
Hydrogen Detector Utilizing Metal-Semiconductor Contacts
Authors: Ito Kentaro
Published: November 2005

A hydrogen detector was developed in which the hydrogen-sensitive palladium/oxide/semiconductor (Pd MOS) Schottky diode and the reference diode were connected in series with each other. The latter diode was made by deposition of a thin gold film on the other Pd MOS structure. The effects by temperature variation and ageing were so compensated that several thousand ppm H2 can be stably detected in the atmosphere ambient. A method of hydrogen detection was proposed where the photovoltaic output of the diode was monitored.
XPS Study of Gd-Co and Gd-Fe Amorphous Films
Authors: Shen Dian Hong , Mizokawa Yusuke , Iwasaki Hiroshi , Shen De Fang , Numata Takuhisa , Nakamura Shogo
Published: November 2005

XPS spectra of Co 2p3/2, Fe 2p3/2 and Gd 4d3/2,5/2 of the Gd-Co and Gd-Fe amorphous films were obtained before and after annealing. As a result of the spectral observation, it is known that the oxide of Co and Fe are easily reduced by annealing in a vacuum of 1×10-4 Torr. The depth profiles of Gd-Co film show that Gd segregates to the surface of the film at room temperature. The segregation of highly reactive Gd aids to reduce the oxide of Co and Fe. Based on the experimental data we can explain the effect of annealing on the compensation temperature and, in some extent, support a pair-ordering model of magnetic anisotropy.
Degradation of ITO Film in Glow-Discharge Plasma
Authors: Kuboi Osamu
Published: November 2005

The degradation of ITO films bombarded by glow-discharge plasmas of H2, Ar, N2, B2H6 (2500 ppm in H2) and PH3 (2500 ppm in H2) are investigated. The ITO film temperature, the plasma bombarding time, and the RF power required to generate the plasma are taken as the parameters of these experiments.
Degradation takes place at the lowest temperature (200–250°C) with the H2 plasma, followed by B2H6 and then by Ar in the order shown in Fig. 3. However, the films are only slightly degraded by the N2 and PH3 plasmas.
SEM observation of degraded ITO films after bombardment with plasma shows that the ITO film in the degraded area separates almost completely from the substrate silicon crystal and is spherodized into many small particles of In-Sn alloy.
A Photoluminescence Study of Amorphous-Microcrystalline Mixed-Phase Si:H Films
Authors: Hata Nobuhiro , Yamasaki Satoshi , Oheda Hidetoshi , Matsuda Akihisa , Okushi Hideyo , Tanaka Kazunobu
Published: November 2005

The results of photoluminescence (PL) experiments are presented for a series of amorphous-microcrystalline mixed-phase (µc-)Si:H films deposited under different rf voltages (RFV's). The present data combined with X-ray diffraction analyses lead to the conclusion that µc-Si:H involves three different components in its structure: microcrystals, a PL-emitting amorphous phase and a non-PL amorphous phase. The structure of the PL-emitting amorphous phase remains unchanged for a wide range of RFV, while its volume fraction varies.
The Very-Small Angle Neutron Scattering from Neutron-Irradiated Amorphous Silica
Authors: Takahashi Toshio , Tomimitsu Hiroshi , Ushigami Yoshiyuki , Kikuta Seishi , Doi Kenji
Published: November 2005

The very-small-angle neutron scattering has been measured for amorphous silica which had been reactor-irradiated with a thermal neutron fluence of 3×1019/cm2 at 48°±2°C. Structural inhomogeneities were revealed with a radius of gyration of 3×105 A. The observation is consistent with that of the very-small-angle X-ray scattering (Suzuki et al. Jpn. J. Appl. Phys. 19 (1980) L205) and with optical microscopy.
Generation and Focusing of Intense Ion Beams in Pinch-Reflex Diode
Authors: Ozaki Tetsu , Miyamoto Shyuji , Imasaki Kazuo , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

Production and focusing of a 0.2 TW proton beam are reported. The beam was produced with a pinch-reflex ion diode set on the high power pulse generator Reiden IV. The diode characteristics were in good agreement with the theoretical model. The ballistic focusing of the beam was performed by the space-charge neutralization. Experimental observations of the beam focal dynamics were in reasonable agreement with calculation of particle orbits.
The Effect of Impurity on the Formation of the √3×√3 (R30°) Surface Phase of the Ag-Si(111) System
Authors: Gotoh Yoshihiko , Chauvet Agathe , Manneville Michel , Kern Raymond
Published: November 2005

Auger intensity versus coverage plots for a polished (111) Si surface deposited with Ag at 400°C were measured to determine the stoichiometry of the √3×√3 (R30°) surface phase. The critical coverage of the transition from 2D growth to 3D growth varies with the quantity of carbon existing on the surface. For a clean surface, the critical coverage is 1.0 or slightly less than 1.0, and as the quantity of carbon increases, the cirtical coverage decreases. The growth of Ag on a contaminated surface is discussed using these results.
Observation of Dark Defects Related to Degradation in InGaAsP/InP DH Lasers under Accelerated Operation
Authors: Fukuda Mitsuo , Wakita Koichi , Iwane Genzo
Published: November 2005

Generation and development of <100> dark line and dark spot defects (DLD/DSDs), and related increases in room temperature pulse threshold current are investigated on InGaAsP/InP double heterostructure (DH) lasers under 10 kA/cm2 forward current density and (250±25)°C junction temperature operation. The average development speed of <100> DLDs is estimated to be about 0.3 µm/h. Temperature rise is confirmed at DSDs with an infrared thermometer. These dark defects have geometrical correlation with etch pit features in the InGaAsP/InP heteroboundary. They are considered to be developed by carrier injection.
Anomalous Electric Field Dependence of Helical Pitches in Ferroelectric Sm C* at Temperatures Close to the Phase Transition to Sm A
Authors: Kondo Katsumi , Sato Yuzuru , Takezoe Hideo , Fukuda Atsuo , Kuze Eiichi
Published: November 2005

The field dependence of the helical pitches in 2-methylbutyl p-(p-n-hexyloxybenzylideneamino) cinnamate has been studied optically using a homogeneously aligned cell of high quality. Near the phase transition from Sm C* to Sm A, the helical pitch depends on the applied field to a much greater extent than that predicted by the unwinding mechanism of the helicoidal structure based on the assumption that the tilt angle is independent of the field. This fact suggests that thermal fluctuations in the tilt angle play an important role in the unwinding mechanism.
Mobility Enhancement in Inverted AlxGa1-xAs/GaAs Modulation Doped Structures and Its Dependence on Donor-Electron Separation
Authors: Morkoç H. , Drummond T. J. , Thorne R. E. , Kopp W.
Published: November 2005

Inverted single period modulation doped Al
x
Ga1-x
As/GaAs heterostructures with the binary compound on top of the ternary, exhibiting enhanced electron mobilities, were grown by molecular beam epitaxy. Despite the early reports of no mobility enhancement, considerable mobility enhancement was obtained simply by growing the structures at extremely high substrate temperatures. Similar to the case where the ternary is on top of the binary, the electron mobility was observed to be strongly dependent on the spacing between the ionized donors and the electron gas. Electron mobilities as high as 30,400 cm2/Vs at 78 K and 37,900 cm/Vs at 10 K were observed in structures having a net electron concentration of about 5×1011 cm-2.
Laser-Induced Fluorescence of Oil Colours and Its Application to the Identification of Pigments in Oil Paintings
Authors: Miyoshi Tadaki , Ikeya Motoji , Kinoshita Shuichi , Kushida Takashi
Published: November 2005

We have investigated the spectra and decay characteristics of the fluorescence produced in oil colours under pulsed laser excitation. It was found possible to identify prigments in paintings by measuring the fluorescence, and it is suggested that the laser-induced fluorescence method can be used to detect forgeries in oil paintings.
Thomson Scattering Measurements in Non-Circular Tokamak TNT-A
Authors: Nagayama Yoshio , Sakuma Kaichiro , Toyama Hiroshi
Published: November 2005

A highly-sensitive, low-noise Thomson scattering apparatus has been developed. Measurements of electron densities of less than 1×1018 m-3 were performed using GaAs(Cs) photomultipliers with a quantum efficiency of over 10%, a light guide system with a high transmittance and a 6 J ruby laser. Detecting the scattered light with longer wavelength than that of the ruby laser protects the signal from disturbance by the plasma light, especially by the Hα line. The time evolutions of the electron temperature and the density profiles of the elongated plasma in the non-circular tokamak TNT-A are presented in this paper.
Measuring Apparatus for Submillimeter Wave Scattering from Plasma Density Fluctuations
Authors: Saito Teruo , Hamada Yasuji , Tanaka Shigetoshi
Published: November 2005

A submillimeter wave-scattering apparatus for studying plasma waves was constructed and used to measure low-frequency fluctuations in tokamak plasmas. An HCN laser (λ=337 µm) and a Schottky barrier diode mixer were developed for use in the scattering apparatus. To calibrate the apparatus, a plastic TPX was used, and it proved to be very useful as a plasma simulator.
In this paper, we describe the scattering apparatus and the plasma simulator and give experimental results obtained with the apparatus in the WT-2 tokamak plasma.
Ergodic Behavior of Magnetic Field Lines in a Poloidal Divertor Tokamak
Authors: Yoshida Hidetoshi , Kishimoto Hiroshi , Tamura Sanae
Published: November 2005

The ergodic behavior of magnetic field lines is investigated numerically in a Tokamak divertor system under the influence of magnetic perturbations. The entropylike quantity introduced into the magnetic system characterizes the property of the magnetic field lines and is related closely to the width of the ergodic layer. The metric entropy of the ergodic field lines is given in terms of the entropylike quantity.
Electric Breakdown of Solution-Grown Polyethylene Films without Spherulite
Authors: Kitagawa Keiichi , Sawa Goro , Ieda Masayuki
Published: November 2005

Self-healing breakdown tests are made at room temperature on solution-grown polyethylene (PE) films without heat treatment. The non heat-treated film has no spherulite and consists of randomly oriented lamellae, in contrast to the heat-treated film consisting of two-dimensional spherulites. The variation of electric strength with voltage rising speed and voltage polarity gives a feature similar to the previous results for the heat-treated films and is again interpreted in terms of roughness of the top surface and space charge formation. The electric strength free from both surface roughness and space charge is higher for the non heat-treated films than for the heat-treated films in which breakdown occurs at spherulite boundaries.
Abnormal Transverse-Field Effects in Nonideal Type 2 Superconductors. II. Influence of Dimension Ratios in a Superconducting Ribbon
Authors: Funaki Kazuo , Nidome Teruhide , Yamafuji Kaoru
Published: November 2005

In a nonideal superconducting wire, a number of strange magnetic phenomena have been observed in an AC magnetic field superposed perpendicularly on a DC bias field. When the DC bias field is applied parallel to the wire axis, these strange phenomena are called longitudinal-field effects, while abnonnal transverse-field effects are observed when the DC bias field is perpendicular to the wire axis.
In this paper, the conditions for the appearance of the abnormal transverse-field effect are investigated in detail for a superconducting Nb50%Ta ribbon. When the dimension ratios were changed, we observed a change in the magnetic behavior from the longitudinal-field to the abnormal transverse-field effect. It is suggested that such a change originates from a change in the pinning characteristics due to various motional styles of flux lines.
A Theoretical Investigation of the Residual Voltage on Electrophotographic Plates
Authors: Okuda Masahiro , Motomura Kota , Naito Hiroyoshi , Matsushita Tatsuhiko , Nakau Tanehiro
Published: November 2005

A numerical analysis of the residual voltage on an electrophotographic plate is presented for a photodischarge process characterized by carrier trapping and release parameters. The physical model is described by a set of one-dimensional transport equations with appropriate initial and boundary conditions. Examples of calculations are given for two models involving one and two hole trap levels.
It is shown that a residual voltage can be derived which is valid for the decay process in amorphous Se film under typical electrophotographic conditions.
For one trapping level, a trapping parameter of w<0.1 and a release parameter of r>10-5 are needed to decrease the residual voltage V
r. With two trapping levels, the residual voltage is mainly influenced by the deep trap E
t1.
Encounter Interactions of Counter-Streaming Laser-Produced Plasmas in Magnetic Field
Authors: Saito Hirobumi , Sato Kohnosuke , Sekiguchi Tadashi
Published: November 2005

Experiments were carried out on the encounter interactions of two laser-produced, counter-streaming plasmas along a magnetic field. This study was motivated by the problem of filling toroidal (typically stellarator) or large-scale open-ended magnetic containers with laser-produced plasma, where simultaneous plasma production at multi-positions in a container is often required. The experimental results indicate that (1) the translational kinetic energy of ions is converted to the plasma thermal energy by encounter interactions and the electron temperature increases by a factor of 3 to 6, and (2) the particle-loss across the magnetic field is not enhanced. Theoretical considerations indicate that the thermalization may be attributed to Coulomb interactions, rather than shock-formation or micro-instability excitations. This thermalization is useful for recovering the thermal energy from the adiabatic cooling of a flowing laser-produced plasma in its expansion phase.
Zn, Te and Se Doping of LPE InGaPAs0.01 Grown on (100) GaAs Substrates
Authors: Mukai Seiji
Published: November 2005

The surface and interface morphology, thickness, lattice constant, and the electrical and photoluminescence (PL) properties of doted InGaPAs0.01 grown by LPE on GaAs at 785°C are investisated as a functnon of Zn, Te or Se dopant concentrations in sources (X
1
Zn, X
1
Te or X
1
Se). The thickness chance caused by doping up to X
1
Zn=8×10-3, X
1
Te=8×10-3 or X
1
Se=10-3 is less than 7% and lattice-constant change is less than 7×10-4. The hole and electron concentration, p and n, mobility, µh and µe, and resistivity ρ are shown as a function of X
1
Zn, X
1
Te or X
1
Se and temperature. 298 K values are: p=1.1×1022
X
1
Zn cm-3, µh=30 cm2/V·s, n=6×1020
X
1
Te or 1.6×1022
X
1
Se cm-3 and 500 cm2 V·s≤µe≤1000 cm2/V·s. Both n- and p-type layers show PL-spectral-peak shifts toward higher energy side with increasing n or p. The PL intensity of n-type layers reaches a maximum for n=2×1018 cm-3 while that of p-type layers only decreases with increasing p.
Cooling and Excitation Tests of a Thin 1 mφ×1 m Superconducting Solenoid Magnet
Authors: Hirabayashi Hiromi , Morimoto Kimio , Wake Masayoshi , Yamada Ryuji , Yamamoto Akira , Mori Shigeki , Yoshizaki Ryozo , Kawakami Hisao , Kondo Kunitaka , Aihara Katsuzo , Kazawa Yoshiaki , Kimura Hiroshi , Ogata Hisao , Saito Ryusei , Suzuki Shohei , Miyake Yasuhiko
Published: November 2005

Cooling and excitation tests of a thin 1 mφ×1 m superconducting solenoid magnet were performed. Quench properties were measured after inducing quenches with a heater. The magnet has a single layer aluminum-stabilized NbTi/Cu superconductor of 269 turns and the forced flow cooling method of two-phase helium was used. The design excitation current of the magnet is 4.5 kA to give a uniform field of 1.5 T with the iron yoke. The magnet was excited up to 6 kA without any unforced quench in the second test in which the iron yoke was absent.
Thresholds for Secondary Light Emission by Noble Gases
Authors: Feio M. Alegria , Policarpo A. J. P. L. , Alves M. A. F.
Published: November 2005

This work concerns the hypothesis that direct excitation of gaseous media by migrating electrons under the influence of weak electric fields is the dominating process by which secondary light is emitted from pure noble gases. Determinations both experimental and theoretical, as well as compilations of previous data, are made for the lower limit of the reduced electric field, for which secondary light emission from gaseous media displays a sharp increase.
A detailed comparison of the theoretical results with more reliable published experimental data shows, in general, very good agreement.
Effect of Ultrasonic Vibrations on InSb Pulled Crystals
Authors: Hayakawa Yasuhiro , Sone Yasushi , Tatsumi Kenji , Kumagawa Masashi
Published: November 2005

InSb single crystals were pulled from the melt by the Czochralski method. During the growth of the crystals, ultrasonic vibrations were introduced into the melt through the carbon crucible. The facet region at the center of the pulled crystals shifted to the periphery of the crystals and simultaneously decreased in size, because the ultrasonic vibrations stirred the melt and raised its temperature. Furthermore, the difference in the values of the spreading resistance between the facet and the off-facet regions also decreased. These results indicate that inhomogeneous distributions of impurity concentration in the crystals were improved by the introduction of ultrasonic vibrations.
Storage Effect in Photostimulated Exoelectron Emission from Scratched Aluminum
Authors: Shigekawa Hidemi , Hyodo Shin-ichi
Published: November 2005

When photoillumination is interrupted, the exoelectron emission from scratched metal samples decays quickly; when the illumination is resumed, however, the recovered exoelectron emission shoots up to a value significantly higher than before and then decreases gradually–a fact overlooked by previous researchers. This transient phenomenon has been studied in some detail as a function of the interval of the interruption and photon energy. To explain our data we propose a model, according to which there are two excitation processes competing during PSEE; one is the photoexcitation of the electrons at defect-related energy levels above the Fermi level, and the other is the thermal excitation of lower-energy electrons to the empty defect-related levels. Rate equations based on this model were found to be in satisfactory agreement with our observations.
Electrolysis in Electrochromic Devices Consisting of WO3 and MgF2 Thin Films
Authors: Yoshimura Tetsuzo , Watanabe Masaki , Kiyota Kohei , Tanaka Masao
Published: November 2005

The role of moisture in the ambient atmosphere on the operation of all-solid-state electrochromic devices has been investigated, and electrolysis of the water in electrochromic devices studied. Because of the dependence of the current passing through MgF2 film on the polarity of the applied voltage, it is suggested that during operation of the devices, water should be supplied only near the surface of the MgF2 film. IMA measurement and direct observation of gas discharge revealed that the water near the surface of the device is mainly dissociated, and that protons flow into the WO3 film through the MgF2 film, resulting in colouration. The colouration behaviour of devices with two different structures leads us to believe that moisture in the atmosphere contributes to more than half the optical density of the device. We also found that bleaching is not always accompanied by dissociation of the water.
Effect of Size on the Strength of Metal Whiskers
Authors: Nohara Akira
Published: November 2005

Optical and electron microscopic observations have revealed that surface steps become noticeable on metal whiskers with larger diameters. Taking into account the stress concentration at the roots of these steps, a dislocation-loop nucleation model is proposed to explain the dependence of the yield strength on size as shown by both fcc and bcc metal whiskers. The proposed model explains the observed size-strength relation very well and is free from the difficulty of the divergence of the yield stress at zero size which is common in empirically-proposed relationships. The decrease in the stacking fault energy brought about by alloying is found to decrease the yield stress.
Estimations of Plasma Position and βp+li/2 from Magnetic Measurements under High-β Conditions in JET-2
Authors: Ninomiya Hiromasa , Suzuki Norio
Published: November 2005

The MHD equilibria of a high-β plasma are studied by carring out magnetic measurements in JFT-2. Equilibrium configurations agreeing well with the experimental results are obtained by numerical calculations, and βp, in the NB injection phase is estimated. Using these calculated equilibrium configurations, two methods of estimating R
p and βp+l
i/2 from magnetic probe signals are also discussed, and the Fourier analysis method is shown to give a more accurate value of R
p and βp+l
i/2 even under high-β conditions.
Signal-to-Noise Ratio in Polarization Modulation Method for Magneto-Optical Measurement
Authors: Abe Masanori , Shono Keiji , Gomi Manabu
Published: November 2005

The signal-to-shot-noise ratio (SNR) in the polarization modulation method using a photomultiplier for measuring a magneto-optic rotation angle \varPsi is calculated as a function or the modulation amplitude a
0, taking the magneto-optic ellipticity angle χ, the extinction ratio of the polarizer, and the partial polarization of the light source into account. The SNR increases to a saturation value of (S/N)0 as a
0 increases, in accordance with the formula S/N=(S/N)0 [1+(2\varPsi2+4\varGamma')/a
0
2]-1/2. Here, \varGamma' is the `practical extinction ratio' of the polarizer, in which the influence of the ellipticity χ as well as the influence of the partial polarization of the light source are included. The SNR measurement was performed at λ=0.63 µm, using a monochromator and polarizers of the Glan-Thompson or dichroic-sheet type. The reult agrees with our calculation.
Optically-Coupled Floating Double Probe for Local Electric Field Measurements in Pinch Discharge Plasmas
Authors: Ishii Shozo , Yokoyama Takayuki , Hayashi Izumi
Published: November 2005

Local electric field signals from a floating double probe immersed in a pinch discharge plasma are transmitted via a pair of fiber optic cables in order to achieve electrical insulation between the probe circuit and an oscilloscope. This optical coupling scheme has a higher electrical insulation voltage and a wider frequency response than the commonly-used isolation transformer methods and commercially-available photocoupler devices. The measuring system consists of a transmitter with light-emitting diodes and a receiver with PIN diodes and responds in the frequency range up to 3 MHz. Transient noise, which disturbs the probe measurements in the implosion phases of pinch discharges, has been eliminated.
Germination and Growth of a Vegetable Exposed to Very Severe Environmental Conditions Experimentally Induced by High Voltage
Authors: Aoki Takashi , Ikezawa Shunjiro
Published: November 2005

Ultra-high-voltage (UHV) transmission power lines are required in order to reduce transmission energy losses, and to transfer more power across long distances. However, the ecological and biological influence of UHV lines has not been documented well. Possible influences of UHV lines are: electro-magnetic field, ozone, NO
x
, and ion shower. The purpose of this study was to obtain information on the germination and growth of Raphanus sativus L.cv. Kaiware-daikon exposed to an experimental environment in which all the above influences at very severe intensity levels were working simultaneously. Several environmental conditions severer than those predicted for future UHV lines were set up, using a high voltage at 60 Hz. The germination and growth of this plant were suppressed under the experimental conditions used, the suppression being greater the severer the conditions. When the electric field is strong, corona discharge occurs at the tip of the plant.
Hydrostatic Pressure Effects on Helical Pitches in Lyotropic Macromolecular Cholesteric Liquid Crystals: Ethyl Acetate Solutions of Poly-γ-Ethyl-D-Glutamate
Authors: Ishikawa Ken , Fukuda Atsuo , Kuze Eiichi , Sawaoka Akira , Tohyama Kohji , Miyata Nahonori
Published: November 2005

A pressure bomb with two straight-through optical windows has been constructed; one of the windows has an angular aperture as wide as ±24°C. It facilitates the obtaining of laser diffraction patterns from which we can determine the helical pitches of cholesteric liquid crystals. Pitches of 16 and 19 wt.% ethyl acetate solutions of poly-γ-ethyl-D-glutamate have been measured by applying pressure up to 200 MPa at several temperatures between 18 and 29°C. The pitch increases with pressure, though no tendency is observed to diverge at a certain pressure.
Magnetization Measurements at High Pressures and Low Temperatures
Authors: Kadomatsu Hideoki , Tohma Kiyokazu , Kurisu Makio , Fujiwara Hiroshi
Published: November 2005

Magnetization measurements at hydrostatic pressures of up to 16 kbar and temperatures from 4.2 K to 300 K were made by adapting the miniature Be–Cu clamp pressure and dummy cells to the conventional integrating type magnetometer. Pressures at 4.2 K and 300 K were determined from the shift in the superconducting transition temperature of Sn with pressure and the structural transition pressure of NH4F, respectively.
Structure and Coalescence Growth of Smoke Particles of Tin Oxides and Lead Oxides Prepared by Burning the Metals in Mixture of Ar and O2
Authors: Kaito Chihiro , Shiojiri Makoto
Published: November 2005

The structure and growth of tin and lead oxide particles prepared in different mixtures of Ar and O2 at a total pressure of 13 kPa were studied by electron microscopy. At partial oxygen pressures below 4 kPa, SnO particles were formed, while above 4 kPa, SnO2 particles were formed. Fine SnO2 crystals were produced on the surfaces of the SnO particles by a topotactic relation represented by (001)SnO//(111)SnO2
and [11̄0]SnO//[011̄]SnO2
. α-PbO and β-PbO particles were predominantly formed below and above an oxygen pressure of 1.3 kPa, respectively. The size distribution of these particles and the distribution of the angle between the lattices of joined particles are presented, and the coalescence growth among the particles is discussed.
Mechanism of Thermal Faceting of Ni4Mo Alloy Emitters
Authors: Kingetsu Toshiki , Yamamoto Masahiko , Nenno Soji
Published: November 2005

The various possible growth models for thermal faceting of emitters of Ni4Mo alloy in a field-ion microscope were considered. The most likely growth mechanism was found for the particular faceting correlated with the six variants of the ordered phase at the surface–order faceting which occurred at 940–870 K (0.83–0.77T
c) of in situ annealing, and for the faceting with FCC configuration–disorder faceting which occurred in either condition, i.e. at higher and lower temperature (1.14–0.98T
c and 0.68T
c). Order faceting is by the following mechanism: (i) the preferential nucleation of a particular orientation variant of the ordered Ni4Mo phase in the surface area corresponding to each {751}FCC type plane, and (ii) simultaneous and cooperative growth of the nucleated ordered phase and the flattenins of each {211}BCT type plane which is parallel to the {751}FCC type plane.
Micro-Probe Reflection High-Energy Electron Diffraction Technique. I. Determination of Crystallographic Orientations of Polycrystal-Silicon Surfaces
Authors: Ichikawa Masakazu , Hayakawa Kazunobu
Published: November 2005

A micro-probe reflection high-energy electron diffraction (RHEED) apparatus including an electron gun with a probe size of 0.1 µm operated under ultrahigh vacuum, has been constructed. This makes it possible to obtain bright, sharp diffraction patterns from micro-areas of clean surfaces, and to take RHEED-microscope images of crystal surfaces. Using this apparatus, a technique for determining the crystallographic orientations of surface micro-areas within an accuracy of ±1° has been developed. This is done by analyzing Kikuchi patterns emitted at low angles, and spatial distributions having various crystallographic orientations are obtained by taking RHEED-microscope images. From the results of applying this technique to polycrystal-Silicon surfaces, it is found that it is very useful in determining the crystallographic orientations of surface micro-areas.
Characterization of Polycrystalline Silicon MOS Transistors and Its Film Properties. I
Authors: Onga Shinji , Mizutani Yoshihisa , Taniguchi Kenji , Kashiwagi Masahiro , Shibata Kenji , Kohyama Susumu
Published: November 2005

The characterization of polycrystalline silicon MOS transistors and its film properties are studied, with special emphasis on the relationship between crystalline defects and carrier transport phenomena. An increase in mobility with gate field in polycrystalline silicon MOS transistors and also with doping concentration in polycrystalline silicon films is observed. These phenomena are interpreted as space charge scattering effects caused by a high density of dislocations in the films. U-shaped drain current vs gate voltage curves are observed both in p-channel and n-channel polycrystalline silicon MOS transistors. The anomalous drain current in the accumulation region is interpreted as junction breakdown at the drain edge caused by crystalline imperfections in the films.
Current Transport in Modulation-Doped AlxGa1-xAs/GaAs Heterojunction Structures at Moderate Field Strengths
Authors: Keever M. , Kopp W. , Drummond T. J. , Morkoç H. , Hess K.
Published: November 2005

Current vs. electric field characteristics of single and multiple period modulation-doped GaAs–Al
x
Ga1-x
As heterostructures are reported for lattice temperatures in the range of 10–300K. Measurements were performed at electric fields up to 2 kV/cm which is below the field range where non-linear effects due to real-space transfer or κ-space transfer (Ridley-Watkins-Hilsum (RWH) mechanism) are expected to occur. The basic heterostructure included an undoped “intrinsic” layer of Al
x
Ga1-x
As between each doped (∼1×1017 cm-3) Al
x
Ga1-x
As layer and undoped GaAs layer. The low field mobilities were found to decrease sharply with increasing electric field at low temperatures, but remained nearly constant at higher temperatures. The low field mobilities of the single period structures showed significant improvement with increasing AlAs mole fraction in the range 0.16≤x≤0.36. The increased mobility enhancement occurs in these structures due to the virtual elimination of electron scattering by increasing the spacing between the donors and electrons with the undoped AlGaAs layers. The current-field characteristics showed this mobility enhancement to increase, reach a maximum and then decrease with increasing undoped layer thickness. At a field strength of 2 kV/cm, modulation-doped single period (x=0.36) structures showed an improvement in current of four times at 78 K and 1.6 times at 300 K, compared to bulk GaAs with identical electron concentration. If used for normally-off field effect transistors (FETs) a speed improvement of 60% at 300 K and 400 % at 78 K can be obtained as compared to conventional normally-off GaAs FETs.
Modulation Phenomena in Ionization Waves
Authors: Yamashita Yoshihiko , Yamamoto Isao , Yoshimoto Hiroshi
Published: November 2005

The nonlinear phenomena of ionization waves in Ar–Hg gas mixtures were analysed experimentally for the case of external current modulations. With a single wave, the nonlinear effects appearing with the growth of the wave cause the wave number to decrease for any given frequency. The dispersion relation for ionization waves is subject to the presence of a dominant wave with natural frequency such that the dispersion relation is expressed by a straight line with a negative slope in the frequency wave number frame. Multi-frequency spectra due to double modulations of the current are explained by assuming nonlinear interactions in the product of two waves or of a wave and an oscillation.
A Set of De-Excitation Rate Coefficients for the 3s 3P2 and 3P1 Levels of Neon
Authors: Tachibana Kunihide , Harima Hiroshi , Urano Yoshio
Published: November 2005

The rate coefficients for the de-excitation of the two lowest-lying excited levels of Ne (3s 3P2 and 3P1) have been investigated in the afterglow of a pulsed discharge in pure neon using absorption and fluorescence techniques. The pressure dependences of the decay rates of the population densities of the two levels and the population density ratio of these levels at low electron and metastable densities yield the de-excitation rate coefficients for these levels by collision with neutral atoms, the diffusion coefficient for the 3P2 atoms and the effective transition probability of the imprisoned resonance radiation for the 3P1 atoms. In addition, from the decay rate of the 3P2 atoms in the early afterglow at appreciable electron and metastable densities, the de-excitation rate coefficients for this level by collisions with electrons and with other 3P2 atoms (metastable-metastable ionization) are deduced.
Numerical Calculation of Optical Eigenmodes in Cholesteric Liquid Crystals by 4×4 Matrix Method
Authors: Sugita Akio , Takezoe Hideo , Ouchi Yukio , Fukuda Atsuo , Kuze Eiichi , Goto Nobuyuki
Published: November 2005

Light propagation in helical structures is formulated as an eigenvalue problem based on Berreman's 4×4 matrix. Diagonalization of the secular equation is carried out to obtain the optical eigenmodes as a function of wavenumber and propagation direction relative to the helical axis, and sets of the optical eigenmodes are found to be classified into four types, whose appearance strongly depends on the wavenumber and the propagation direction. The selective and total reflections in cholesteric liquid crystals are characterized by the types of the eigenmodes for various angles of incidence.
Effects of Backside Oxidation on the Size of Oxidation Induced Stacking Faults at the Front Surface of FZ Si Wafers
Authors: Mizuo Shoichi , Higuchi Hisayuki
Published: November 2005

The effect of backside oxidation on the size of Oxidation induced Stacking Faults (OSF) at the front side of FZ Si wafers has been investigated by Backside Selective Oxidation (BSO). The results show that shrinkage of OSF under directly formed Si3N4 film is interrupted by BSO. However, shrinkage under double-layered SiO2–Si3N4 film is not affected. These results are consistent with the effects of BSO on diffusion of B, P and Sb. The behavior of the OSF's can be explained by the supposition that the Si–SiO2 interface has the effect of preserving the point defect concentration constant and the Si–Si3N4 interface has no such effect.
The Surface Free Energies of Solid Chemical Elements: Calculation from Internal Free Enthalpies of Atomization
Authors: Mezey L. Z. , Giber J.
Published: November 2005

It is pointed out that the experimentally-measured quantity usually termed “surface free energy” is in fact a part of the free enthalpy which is due to the presence of the surface (referred to unit surface). This quantity, denoted by γi
o for the polycrystalline solid chemical element i, is connected to the internal free enthalpy of atomization Δ
G
a,i
* by the relation

γi
oφ
i

o=αi
o
Δ
G
a,i
*

where φi
o is the molar surface area, and αi
o is a constant. Its physical meaning is given to a relatively good approximation. Approximate methods of calculation based on experimental data give values of αi
o at any temperature for metallic, semimetallic and covalently-bonded solid chemical elements. Using these procedures, the values of γi
o at 298.2 K and at the melting temperature are tabulated.
Photoconduction in Polytetrafluoroethylene Induced by Vacuum-Ultraviolet Light
Authors: Yun Munsoo , Yoshino Katsumi , Inuishi Yoshio , Kawatsu Motoo
Published: November 2005

Intrinsic photoconduction in poly tetrafluoroethylene (PTFE) and its dependence on the applied field strength and polarity are investigated in the photon energy range between 7 eV and 11.5 eV. The band gap of PTFE is evaluated from the photoconduction spectra using an Au-PTFE-Au system. The photocurrent increases instantly to a steady value after step-wise irradiation by vacuum-ultraviolet light, contrary to polyethylene, in which the photocurrents increase very slowly. The photocurrent observed with a negative bias applied to the irradiating-side electrode is much less than that under positive bias, indicating that positive carriers such as holes play the predominant role.
Synthesis of Fine Fe4N Powder and Its Magnetic Characteristics
Authors: Tagawa Kimiteru , Kita Eiji , Tasaki Akira
Published: November 2005

A pigment of Fe4N particles for magnetic recording was prepared by nitrogenizing acicular metal iron powder. The chemical treatment needed to obtain stoichiometric Fe4N powder was studied, and it was found that Fe4N powder was obtained when the Fe powder was heated at about 400°C in a mixture of H2–NH3 (65–80 vol.%). The Curie point of the powder coincided well with that of bulk Fe4N. The coercive force of Fe4N was 640 Oe, which is considerably smaller than that of the Fe powder used as the starting material. The dispersion of magnetic anisotropy was measured by a torque meter, and the decrease in the coercivity of nitrogenized iron powder was attributed to the exchange anisotropy of the surface layer.
Long-Pulse Ion Source Using Filament-Free LaB6 Multi-Cathodes
Authors: Kubota Yusuke , Uramoto Jōshin , Miyahara Akira
Published: November 2005

A prototype of a new ion source for neutral beam injection has been developed. To produce a uniform, high current density ion beam over a large area, the discharge electrode rows are arranged as two parallel channels in this source. A power supply system with two discharge current controllers is used to obtain arc discharges smoothly. In this system, the use of series resistors ana diodes was effective in eliminating mutual interaction between the two discharge regions. Preliminary experiments on high-density plasma production were carried out successfully in a quasi-steady mode. The ion current density estimated from the ion saturation current was as high as 0.25 A/cm2 12 cm from the extractor grid surface over an area of 10 cm × 15 cm with a transverse inhomogeneity of less than 10%.
A Method for Studying Optical Eigen Modes in Cholesteric Liquid Crystals by Using Stress Plate Modulators in Tandem
Authors: Takezoe Hideo , Sugita Akio , Ouchi Yukio , Hara Masahiko , Fukuda Atsuo , Kuze Eiichi , Goto Nobuyuki
Published: November 2005

An apparatus has been constructed for the direct study of the optical eigen modes (OEM's). The apparatus consists of an He–Ne laser, a linear polarizer (LP), a stress plate modulator (SPM), another SPM, another LP and a photomultiplier tube (PMT). A sample is placed between the SPM's, and the first combination of LP and SPM acts as a dynamic elliptical polarizer and the second one constitutes the analyzer which is always perpendicular to the polarizer. The output signal from the PMT is recorded in a transient memory and is accumulated and processed by a microcomputer. Taking the OEM propagating along the cholesteric helical axis as a test example, we calculated the temporal change in the PMT output signal; it indicates the existence of an ellipticity which gives zero transmittance. The calculated dependence of the ellipticity on wavelength agrees qualitatively with that of the true OEM, except for the region near or in the characteristic reflection. By performing actual measurement with a monodomain cholesteric film at a certain wavelength, we confirmed that the apparatus works well.
Aging Effect of Capacitance and Related Effects in Au/a-Se/Al Structure
Authors: Ema Yoshinori , Hayashi Toshiya
Published: November 2005

The contact between an a-Se and an Al electrode was found to show some characteristic features. When samples of the Au/a-Se/Al structure were kept in air, their capacitance first decreased and then increased. At the same time, their photocurrent and photovoltage increased gradually with time, and their spectral responses shifted. A chemical EMF appeared in the samples, also. The capacitance of the samples became voltage-dependent after a long time. These aging effects could be explained well by considering them to be the result of Se crystallization based on the migration of Al ions into Se assisted by the chemical reaction of Se and Al in moisture (H2O). The migration of Al ions and the structural change of the a-Se layer with time were confirmed by AES, RHEED and X-ray diffraction analyses. Al ions migrating into the Se layer are thought to act as nuclei for the crystallization of a-Se.
High-Voltage Photovoltaic Effect in PbTiO3-Based Ceramics
Authors: Uchino Kenji , Miyazawa Yuichi , Nomura Shoichiro
Published: November 2005

The existence of the photovoltaic effect has been confirmed in 0.895PbTiO3–0.105La(Zn2/3Nb1/3)O3 solid solution ceramics with and without MnO2 doping. The electrode-configuration dependence, illumination response and aging effect of the photovoltaic current or voltage have been investigated in the two specimens. With 1.5 mol% MnO2 doping, the photocurrent decreases and the photovoltage increases by an order of magnitude each. The relation between the dark and the photo-induced conductivities is also discussed briefly in this report.