bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of the Persistent Oxygen Impurity Density in a Theta Pinch Plasma by VUV Absolute Intensity Measurements
Authors: Okazaki Kiyohiko
Published: February 2005

An order of magnitude estimation of the oxygen density is carried out in a helium plasma produced by a small linear theta pinch from the absolute intensity measurements in a VUV (vacuum ultraviolet) wavelength region using a grazing incidence spectrometer absolutely calibrated by the branching ratio method. The corona model is used for the analysis, and its applicability is discussed to this plasma in terms of the electron temperature and density which are estimated from the measurements in the VUV wavelength region. The ratio of total oxygen density to the electron density is about 0.02% in a discharge of helium gas of 99.9% purity. The origin of the oxygen atoms is discussed.
Photoconduction in Poly(p-Phenylene Sulfide) Films near the Absorption Edge
Authors: Tanabe Yoshikazu , Shimizu Hiroshi , Minami Nobutsugu
Published: February 2005

Steady state photocurrent of pristine poly(p-phenylene sulfide) with a rather low impurity content was measured under the condition of low light intensity and a low applied electric field. A very sharp peak in the photocurrent spectrum was observed at 370 nm in the vicinity of the absorption edge. The photocurrent increased linearly with the light intensity and with the applied electric field, while it was only slightly affected by the polarity of the applied voltage. These experimental results can be explained by the diffusion model of photocarriers with the very large surface recombination rate under the low applied field. Temperature dependence of the photocurrent and dark conductivity is also discussed.
Self-Development Properties of Nitrocellulose for Focused Ion Beam Lithography
Authors: Kaneko Hidehiko , Yasuoka Yoshizumi , Gamo Kenji , Namba Susumu
Published: February 2005

A method for obtaining the reproducibility of the self-developed pattern of nitrocellulose by monitoring the absorption current was investigated. For the nitrocellulose films with 3 different thicknesses, the change of the absorption current and the progress of the self-development were observed as a function of the irradiation time of the focused ion beam (FIB). Using our method, line patterns with a good reproducibility were obtained independent of the thickness of the nitrocellulose film. The width of the aluminum lines fabricated by our method was 160nm.
Ac Surface Photovoltages in p-Type Silicon Wafers Oxidized in Water-Free and Wet Ambients
Authors: Munakata Chusuke , Tamura Hiroshi , Honma Noriaki , Ozawa Masami , Yagi Kunihiro
Published: February 2005

Ac surface photovoltages in a CZ-grown p-type silicon wafer oxidized with water-free dry oxidation deviate from the normal inverse frequency characteristics observed in the wafer oxidized with the conventional wet oxidation. This is because of dense interface traps inherent to the water-free oxidation.
Shadow-Projection X-Ray Microtomography for Line-Like Objects
Authors: Aoki Sadao , Oshiba Mitsuo , Kagoshima Yasushi
Published: February 2005

An X-ray microtomographic system for line-like objects has been constructed with a conventional microfocus X-ray generator. A relatively high resolution (∼10µm) has been attained. The enhancement of the image contrast has been demonstrated by utilizing the absorption edge of the sample.
Electrical Properties of Langmuir-Blodgett Films Sandwiched between Pb–Bi Superconducting Electrodes
Authors: Iwamoto Mitsumasa , Shidoh Shun-ichi , Kubota Tohru , Sekine Matsuo
Published: February 2005

We have examined the electrical properties of insulating layers of both cadmium arachidate (C20) and polyamic acid long alkylamine salts (PAA), which are sandwiched between Pb–Bi superconducting electrodes, at a temperature below the critical temperature of a Pb–Bi alloy. Typical I-V characteristics of weak-coupled superconductors are shown in the absence of microwave powers, and normal step structures are shown in the I-V characteristics in the presence of microwave powers. We found that metallic pathways exist in the LB films. From the solution of Ginzburg-Landau equations, we obtained the result that the diameter of the metallic pathways is smaller than the London penetration depth of the Pb–Bi alloy. Finally, we concluded that although the bridging filaments exist in the LB layers, the efficiency of detecting microwaves is excellent in our SIS device.
Conduction Current Relaxation of Inhomogeneous Conductor I
Authors: Yamamoto Kazunao , Namikawa Hiroshi
Published: February 2005

To explain the low-frequency dielectric relaxation of many types of materials, the current relaxation phenomenon induced in an inhomogeneous conductor with a spatial distribution of local conductivity is investigated. The nonuniform current density produces the true charge (conduction charge). The origin of the relaxation current is the change of the local electric field with time caused by the conduction charge. It is more appropriate to call this current relaxation phenomenon “conduction current relaxation” rather than the dielectric relaxation, because there is no definite relation between the relaxation current and the dipole moment due to the distribution of the conduction charge. The conduction current relaxation induced in the inhomogeneous conductor having the conduction path structure can simulate the low frequency dielectric relaxation of oxide glass.
Deterioration of Superconductive Character of Y–Ba–Cu Oxides in Time Duration
Authors: Matsui Hisayuki , Ito Susumu , Nakagawa Ippei , Takeda Michio , Yasuda Kyoichiro
Published: February 2005

The electrical resistivity and magnetic susceptibility of a superconductive [1:2:2] and an electron-irradiated [1:1:2] Y–Ba–Cu oxide were examined in time duration for about one year. There was no remarkable change in the superconductive character within a few months. After half a year, however, a deterioration of the superconductive character seemed to be accelerated. In particular, the electron-irradiated [1:1:2] Y–Ba–Cu oxide showed a significant deterioration in the electric and magnetic characters of the superconductivity.
Deep Electron Traps in AlAs-GaAs Superlattices as Studied by Deep-Level Transient Spectroscopy
Authors: Kobayashi Kikuo , Morita Masahiko , Kamata Norihiko , Suzuki Takeo
Published: February 2005

Deep electron traps in Si-doped AlAs-GaAs superlattices (SLs) grown by MBE have been investigated using deep-level transient spectroscopy (DLTS). The concentration of the characteristic electron trap (E2 trap) in the SLs increases upon decreasing the period of SL and increasing the Si doping concentration. The E2 trap concentration for uniformly Si-doped SLs is more than one order higher than that for SLs doped selectively at the middle part of each AlAs and GaAs layer. The E2 traps have properties similar to the so-called DX centers in Al
x
Ga1-x
As, and they exist only in the AlAs-GaAs interfaces. The different activation energies of the traps in SLs and Al0.3Ga0.7As can be explained in terms of carrier emission from the E2 trap to the mini-band levels of the SLs and to the conduction band minimum of the alloys, respectively.
Study on Narrow-Stripe Polycrystalline Silicon Thin-Film Transistors
Authors: Takeshita Tatsuya , Unagami Takashi , Kogure Osamu
Published: February 2005

N-channel thin-film transistors which have narrow channel stripes (narrow-stripe TFT's) have been proposed to improve the characteristics of poly-Si TFT's. The carrier mobility of narrow-stripe TFT's is larger than that of conventional structure TFT's. It is found that the mobility increase is due to the reduction of the potential-barrier height at the poly-Si grain boundary and the potential-barrier height decreases with decreasing channel stripe width. Furthermore, after hydrogen-plasma treatment, the carrier mobility in narrow-stripe TFT's with 0.9µm wide stripes becomes 7.4 cm2/(V·s) which is more than three times that of conventional TFT's.
DC Plasma Current Drive by Means of a Rotating Magnetic Field
Authors: Suzuki Mitsuaki , Hotta Eiki
Published: February 2005

The transient process and steady state of a current drive by means of a rotating magnetic field (RMF) are analyzed using the Lorentz transformation and linearized cold plasma wave theory. In the analysis, we consider the distortion of RMF by the screening current flowing in plasma consistently and derive the magnitude of the applied RMF which is necessary to make electrons rotate synchronously with the RMF. It is shown that the transient motion of ions plays an important role, especially in the start-up phase of the current drive, because the motion decides whether a steady state current can be driven or not. The efficiency of the current drive is shown to be equal to that of an ohmically current drive.
Suppression of Longitudinal Coupled-Bunch Instability by Decoupling Method
Authors: Kasuga Toshio , Yonehara Hiroto , Hasumoto Masami , Kinoshita Toshio
Published: February 2005

The decoupling method to suppress the longitudinal coupled-bunch instability in the UVSOR electron storage ring was tried. Synchrotron frequencies of individual bunches were spread by means of the modulation of the effective acceleration voltage in order to decouple these synchrotron oscillations. The instability is successfully damped by this method when the beam current is not high and the growth rate is moderate. The limitation of this method is not in the principle but in the maximum modulation index available in this experiment.
New Asymmetrical Double-Layered Guest-Host Liquid Crystal Displays with Improved Optical Performances
Authors: Ong Hiap Liew
Published: February 2005

Significant improvement of gray scale capability, faster response times, higher contrast ratio, and symmetrical display performance can be obtained in a new asymmetrical double-layered Guest-Host nematic liquid crystal cell geometry. A theoretical model describing the electro-optical performance in the principal viewing zone is shown.
Optical Methods for the Measurement of Layer-Tilt and Pretilt Angles in Surface-Stabilized Ferroelectric Liquid Crystal Devices
Authors: Yang K. H. , Lien A. , Chieu T. C.
Published: February 2005

We have used simple optical methods to determine, simultaneously, the layer-tilt, pretilt, quiescent state azimuthal, and tilt angles of surface-stabilized ferroelectric liquid crystal (SSFLC) devices as a function of temperature. In a SSFLC cell aligned by rubbed polymer films, the measured pretilt angles are small and the layer-tilt angle is, in general, less than the tilt angle for the same material at any given temperature in the smectic C phase. The measured pretilt, layer-tilt, angles show a common tendency to converge to zero as the temperature approaches the smectic C-to-A transition, while the azimuthal angle of the director in the stable quiescent state increases toward 90°. We observed that the direction of rubbing for alignment was parallel to the projection of the layer-normal onto the substrate surface within the temperature range of the smectic C and smectic A phases.
Breakdown of a Mixture of Silicone Oil and PE Powders in a Positive Point-to-Plane Electrode System
Authors: Arii Kiyomitsu , Kitani Isamu
Published: February 2005

The breakdown voltage, V
b, of silicone oil mixed with polyethylene (PE) powders was measured in a positive point-to-plane electrode system. In the dc case, V
b had a maximum value at a PE particle to silicone oil volume ratio of about 30%. The conduction current was larger in silicone oil than in the mixture; this could be explained by a smaller liquid flow in the latter. In the pulse test, using PE particles with a mean radius of 3 µm, V
b increased with increasing the ratio. A possible mechanism of the positive streamer is discussed with the help of a simplified model.
Superconductivity of Tl-Sr-Ca-Cu-O System in Relation to Tl-Ba-Ca-Cu-O and Bi-Sr-Ca-Cu-O Systems
Authors: Matsuda Shimpei , Takeuchi Seiji , Soeta Atsuko , Suzuki Takaaki , Aihara Katsuzo , Kamo Tomoichi
Published: February 2005

It was found that Tl-Sr-Ca-Cu-O system gives rise to at least two superconducting phases, a high-T
c phase at 100 K and a low-T
c phase at about 75 K. The two phases are isostructural to those of Bi-Sr-Ca-Cu-O system. Comparing the T
c's and crystal structures of the Tl and Bi systems, it was suggested that T
c is mainly determined by the combination of two alkaline earth elements, i.e., Sr/Ca or Ba/Ca, when the repetition unit in the layered perovskites is equal.
Microstructure of Bi1.5Y1.5Fe5O12 Films Made by Pyrolysis
Authors: Gho Jaekyong , Gomi Manabu , Abe Masanori
Published: February 2005

Bi-substituted iron garnet films 0.06 µm ∼0.06 µm in thickness (t) were made by prolysis. They were subjected to SEM and optical microscopic observations of microstructures. Starting around 600°C, the crystallization of the films proceeded to 60°C. Crystalline Crystalline grains 1 µm ∼ 2 µm in diameter were observed. A considerable amount of amorphous phase remained in thinner (t< 0.3 µm) films even after they were annealed above 660°C for a sufficient time. The saturation magnetization and Faraday rotation of the films thinner than 0.3 µm were considerably smaller than those in bulk samples, which might be ascribed to the amorphous phase. The thinner the film, the larger the amount of amorphous phase remaining, because surface free energy (which obstructs crystalline grain growth) increased as the film thickness decreased.
DLTS Study for Energy-Broadening of the Defect Level on Introducing Radiation Damage in GaP
Authors: Endo Tamio , Nishimura Takao , Nakakuki Kiyoshi , Kitamura Mamoru , Sugiyama Koichi
Published: February 2005

Measurements of deep-level transient spectroscopy (DLTS) have been made on the n-GaP before and after electron irradiation at 10 MeV. The density of an electron trap with an activation energy of 0.38 eV, which originally exists in the as-grown crystal, is reduced by the irradiation at an average reduction rate of 0.07 cm-1. The DLTS spectrum for this trap is broadened with irradiation and sharpened with successive annealing. The level broadening ΔE
t of the trap is estimated by the simulation technique. ΔE
t increases (decreases) with increasing (decreasing) width of the DLTS spectrum according to the introduction (annihilation) of radiation defects. The calculated average potential fluctuation is close to ΔE
t(=70 meV) for the irradiated sample with 1 × 1017 electrons/cm2, implying that the level broadening arises from the band-edge broadening.
Hydrostatic Pressure Dependence of Raman Spectra in CdSiP2 Crystal
Authors: Shirakata Sho
Published: February 2005

Raman scattering measurements in the CdSiP2 single crystal have been performed under hydrostatic pressure up to 72 Kbar. Eleven first-order and three second-order Raman peaks have been studied. From the shift of Raman peaks, Grüneisen parameters were obtained. Based on Grüneisen parameters, phonon modes are examined and related to the modes in the zincblende-type binary analog. In addition, the pressure-induced changes in the Raman intensity and half-width have been examined. Furthermore, the discussion includes the soft-mode phonon and the density of the phonon state.
Space Radiation Effects on Mechanical Properties of Carbon Fibre Reinforced Plastic
Authors: Sonoda Katummi , Enomoto Junzou , Nakazaki Kouichi , Murayama Kunihiko
Published: February 2005

Degradation behavior of the mechanical properties of CFRP (carbon fibre reinforced plastic) under electron beam irradiation in various conditions has been studied, with a view to doing simulation experiments in space. It was observed that the flexural strength of notched specimens of CFRP decreased more rapidly with the increase of the dose in air than in vacuum. Some decrease in flexural strength was observed with the increase of the dose at elevated temperatures. The lower dose rate resulted in a further decrease in flexural strength when compared with the same total dose. Volatile byproducts from CFRP during radiation in vacuum were measured by GC (gas chromatography) and GC/MS (gas chromatography/ mass spectrometry) analysis. The chemical components extracted from irradiated specimens were analysed by means GPC (gel permeation chromatography). The degradation of epoxy resin was characterised by FTIR (Fourier transform infrared spectroscopic analyser) spectra. Based on these analyses, the degradation mechanisms of irradiated CFRP are discussed in this paper.
Lamellar and Bulk Single Crystals Grown in Annealed Films of Vinylidene Fluoride and Trifluoroethylene Copolymers
Authors: Ohigashi Hiroji , Akama Shuyo , Koga Keiko
Published: February 2005

Thick lamellar single crystals and large bulk single crystals are found to grow in films of vinylidene fluoride and trifluoroethylene copolymers when they are annealed at temperatures between the Curie point and melting point. The morphologies of these crystals are studied using SEM, TEM, and X-ray diffraction. The lamellar crystals are thick (0.1 µm) enough to be characterized as extended chain crystals. They are stacked together with their planes perpendicular to the film surface. The bulk single crystals exhibit various crystal habits with the maximum size 12 × 10 × 10 µm3. They are developed on the lamellar crystals from which the constituent molecules seem to be supplied. The growth of the crystals is discussed on the basis of the diffusive displacement of the molecules along the chain axis which becomes violent above the Curie temperature.
Compensation Effect in the Electrical Conduction Process in Some Nucleic Acid Base Complexes with Proflavine Dye
Authors: Sarkar D. , Misra T. N.
Published: February 2005

Compensation behaviour has been found in electrical conduction process in proflavine complexes with nucleic acid bases, guanine, adenine, uracil and thymine. At low dye concentrations these semiconducting complexes follow a three constant compensation equation σ(T)=σ0' exp (E/2kT0) exp (-E/2kT), σ0' andT0being constants for a specific base. The other notations have their usual meaning. Consistent values of these constants have been obtained by different experimental methods of evaluation. These results suggest that compensation effect has a physical origin.
An ac Calorimetric Method for Measuring Thermal Diffusivity of Liquids
Authors: Hatta Ichiro , Sakakibara Kiyohiko , Suzuki Juji , Yao Haruhiko
Published: February 2005

By applying ac calorimetry, three methods are proposed for thermal diffusivity measurements in liquids. In these methods the distance between an ac-heat source and a thermometer in liquid is changed and the decay of the ac-temperature wave is observed as a function of the distance. From the relation of the ac-temperature amplitude vs distance, the thermal diffusivity of the liquid can be determined directly. These methods are also capable of measuring the heat capacity per unit volume and the thermal conductivity.
Intensity Control of Emission Spectra in the He-Cd Mixture for a White Light Laser
Authors: Wang Yu-zhi , Li Zi-li , Fujii Kan-ichi
Published: February 2005

By means of a special auxiliary discharge, additional positive helium ions were injected into a traditional flute-type He-Cd hollow cathode discharge, so as to realize the endoergic charge transfer process [K. I. Fujii: Proc. 10th Symp. Ion Sources & Ion Assisted Technology, Tokyo, 1986. p. 77] within the cathode cylinder. Spectroscopic measurements of spontaneous emission showed that a considerable increase in the strength of the red lines (6355 Å, 6360 Å) and of the green lines (5337 Å, 5378 Å) was achieved. This method is expected to be useful in the design of color-controllable white light lasers of the He-Cd+ hollow cathode type.
Spectral Analysis of Deep Level Transient Spectroscopy (SADLTS) of Deep Centers in CdTe Single Crystals
Authors: Morimoto Jun , Fudamoto Michihiro , Tashiro Shuuji , Arai Masaaki , Miyakawa Toru , Bube Richard H.
Published: February 2005

Deep levels in p-type CdTe were studied by SADLTS (spectral analysis deep level transient spectroscopy). Three levels, labeled as A(0.57 eV), B(0.20 eV) and C(0.10 ev) were found. The B and C levels which have, so far, been considered as a single level, have been resolved into two closely spaced levels in our method. Moreover, these two levels were found to have emission rate spectra with finite widths rather than discrete ones. The analysis of the emission rate spectrum indicates that there is a finite distribution in the capture cross section of deep levels.
Magnetic Properties and Magnetization Process in CoCr Films Sputtered on Low-Temperature Substrates
Authors: Honda Shigeo , Takahashi Kenichi
Published: February 2005

Saturation magnetizations, M-T curves and Curie temperatures are measured for the CoCr films sputtered on polyimide films of 27degC. Their properties resemble those of CoCr bulk materials because of the homogeneous morphology. Furthermore, the films with a highly oriented c-axis show perpendicular hysteresis loops having a sharp shoulder and low coercivity. In these films, therefore, the nucleation and the strip-out of the reversed domains are clearly observed by the Bitter method when the external field is decreased from the saturation field. The domain pattern and the magnetization process can be interpreted accurately by the domain theory assuming the domain wall motion.
10 Channel Grating Polychromator for the Measurements of Electron Cyclotron Emission
Authors: Kawahata Kazuo , Sakai Kiyomi , Ando Ritoku , Ohara Sinji , Fujita Junji
Published: February 2005

A 10-channel grating polychromator has been developed and applied for the measurements of the second harmonic electron cyclotron emission from the JIPP T-IIU tokamak plasma. The frequency resolution measured at 150 GHz is about 3 GHz which corresponds to the spatial resolution of 1.8 cm near the center of the plasma column. The grating efficiency is about 80% for S-polarization around 160 GHz. Its excellent time resolution, Δt≤2 µs, is favorable for studying MHD activities in hot plasmas. It has been found from the measurements in JIPP T-IIU that the grating polychromator is a powerful diagnostic tool for the measurements of electron temperature of the plasma.
Steady Plane Orthogonal Electromagneto-Fluiddynamic Incompressible Flows with Isometric Geometry
Authors: Chandna O. P. , Chandna Alka
Published: February 2005

This work achieves two objectives in the study of steady plane orthogonal electromagneto-fluid dynamic incompressible flows when the charge density is not identically zero. The first objective was to give a method of solving flow problems and the second was to determine all possible flow geometries when the streamlines and their orthogonal trajectories form an isometric net.
Integrability conditions are derived for two of the scalar fields and a method of solving flow problems is given along with two flow problems as our examples.
Flows with isometric geometry are then investigated and the results obtained are our extension from ordinary fluid dynamics to these flows.
Joule Loss on a Faraday Shield of JT-60 ICRF Test Antenna
Authors: Fujii Tsuneyuki , Saigusa Mikio , Ikeda Yoshitaka , Kimura Haruyuki , Hirashima Teruhisa , Uehara Munenori
Published: February 2005

Joule loss on a Faraday shield of JT-60 ICRF test antenna with a conductive casing is investigated at the frequency range of 120 MHz. The magnetic field radiated from the antenna is measured by three-dimensionally scanning an rf probe both inside and outside the antenna casing. The magnetic field perpendicular to the Faraday shield, B

x
, is found to be the largest component near the Faraday shield. It consequently gives the major part of the joule loss on the Faraday shield. The temperature distribution of the Faraday shield due to joule loss is measured directly with a thermocamera. It is confirmed that the area of the high temperature rise is consistent with the peak positions of the B

x
field. Faraday shield resistance which is estimated from power measurements agrees with the theoretical value.
Magnetic Probe System on JT-60
Authors: Neyatani Yuzuru , Yamashita Yukihiko , Yokomizo Hideaki
Published: February 2005

We have constructed a data processing system for magnetic probes on JT-60. The signal to noise ratio achieved is over 500 for output signals as a result of the careful calibrations. This system can be used for the off-line calculation of plasma parameters such as plasma positions, Shafranov lambda, etc. MHD fluctuations are also measured. The m=3 fluctuations in the peripheral region with the same frequency of SX and FIR signals are observed. The magnetic fluctuations just prior to the disruptions were measured effectively using the pretrigger function.
Preparation of Mo-N Films and Characterization of Oxide Barriers in NbN/Mo-N Josephson Junctions
Authors: Noya Atsushi , Kuriki Shinya , Mizuno Koichi
Published: February 2005

NbN/Mo-N junctions with bias-sputtered Mo-N counter electrodes and NbN electrodes with plasma-oxidized barriers exhibit SNS-type or SINS-type I-V characteristics, depending on the oxidation condition. It is found from AES and XPS studies that these junction properties are attributed to the composition and oxidation state of barriers.
The Transient Behavior of Light Transmission and Faraday Rotation in Magnetic Fluids
Authors: Yusuf Nihad A.
Published: February 2005

The transient behaviour of light transmission and Faraday rotation in magnetic fluids in a pulsed magnetic field have been studied. The results show that the rise time for the transmission and Faraday rotation are about 120 µs and 160 µs, respectively, while the corresponding relaxation times are 180 µs and 240 µs. These long rise and relaxation times suggest that chain formation plays an important role in the transmission and Faraday rotation.
Trimethylgallium Supply without the Use of Bubbling in GaAs Growth by Metalorganic Vapor Phase Epitaxy
Authors: Ohuchi Atsushi , Ohno Hideo , Ohtsuka Shunsuke , Hasegawa Hideki
Published: February 2005

In the growth of GaAs by metalorganic vapor phase epitaxy using trimethylgallium (TMG), TMG is usually transported by H2 carrier gas saturated with TMG. Saturation of H2 is normally done by bubbling H2 gas through liquid TMG. Here, we show that saturation of H2 with TMG can be achieved through flowing H2 over the liquid or solid TMG, i.e. without the use of bubbling. The growth rate of GaAs grown by TMG supplied in this way with AsH3 showed a linear dependence with the flow rate of H2 over TMG regardless of whether TMG was liquid or solid.
Observations of High Ion Temperatures in a Reversed Field Pinch Plasma
Authors: Hirano Yoichi , Nogi Yasuyuki , Shimada Toshio , Maejima Yoshiki , Yagi Yasuyuki , Ogawa Kiyosi
Published: February 2005

The ion temperature, T
i, of reversed field pinch plasmas was measured by means of a neutral particle energy analyzer (NPA) and by measuring the Doppler broadening of a CV line (227.091 nm) in TPE-1RM. The results obtained by these two methods agree within the experimental error. The measured T
i is about 600–800 eV and is higher than T
e0, the central electron temperature measured by Thomson scattering. This fact cannot be explained by the classical ion heating mechanism and suggests that an anomalous ion heating mechanism exists in the RFP plasma. This high T
i seems to correspond to the bulk of the ions. T
i increases with the plasma current over the range of 55–100 kA.
Magic Numbers in a Mass Spectrum of Lithium Clusters Emitted from a Liquid Metal Ion Source
Authors: Saito Yahachi , Watanabe Makoto , Hagiwara Takayuki , Nishigaki Satoshi , Noda Tamotsu
Published: February 2005

Lithium ion clusters Li
n

+ with n ranging up to 19 have been observed from liquid lithium ion sources by using a magnetic mass analyzer. The ion intensity as a function of cluster size showed local maxima at n=7, 9, 13, and 19. Only n=9 and 19 can be explained by the electronic shell model, which successfully predicts magic numbers of other alkali metal (Na, K) clusters. On the other hand, the geometrical atom packing model explains the observed magic numbers except for n=9.
Annealing Behavior of Be- and Mg-Implants in GaAs
Authors: Humer-Hager T. , Zwicknagl P.
Published: February 2005

Mg+ and Be+ ions were implanted into semi-insulating GaAs with doses ranging from 1014 to 2·1015 cm-2. Both implants were annealed by furnace anneal (FA) as well as by rapid thermal anneal (RTA) with various annealing temperatures and were analyzed by Secondary Ion Mass Spectroscopy (SIMS), Hall and electrochemical carrier profile measurements. Both Mg and Be as-implanted profiles can be fitted by Pearson-IV distributions. After RTA SIMS measurements show significant diffusion only for high-temperature anneals. In this case Be exhibits large diffusion tails and distinct steps in the atomic profile, whereas Mg shows only a slight dopant redistribution. However, after FA generally strong dopant redistribution and surface peaks can be observed. Mg implants yield lower activation and higher sheet resistances than Be when identical implantation doses and annealing cycles are used.
Effect of Molecular Structure of Core on Ferroelectricity in Ferroelectric Liquid Crystals
Authors: Taniguchi Hiroki , Ozaki Masanori , Nakao Kenji , Yoshino Katsumi , Yamasaki Noritsugu , Satoh Kazuo
Published: February 2005

By using various couples of ferroelectric liquid crystals with molecular structures which were only different in the core center in each couple, the effect of the bond moment C=O at the center of core on ferroelectricity could be studied. The bond moment C=O at the center of the core was found to enhance the spontaneous polarization except for one case.
Fluorescence from Colours Used for Japanese Painting under N2 Laser Excitation
Authors: Miyoshi Tadaki
Published: February 2005

The fluorescence spectra have been measured for various colours used for Japanese painting in order to identify the pigments in paintings. Fluorescence was observed in various natural and synthetic colours. The fluorescence intensities of these colours are generally weaker than those of oil colours.
Optical and Electron Beam Requirements for an Optical Undulator FEL
Authors: Tsunawaki Yoshiaki , Amir Avner , Gallardo Juan C. , Elias Luis R.
Published: February 2005

Counterpropagating strong electromagnetic radiation is interesting as a short-period “optical undulator”. This work presents a basic discussion concerning the requirement for electron beam quality in an optical undulator FEL. In the Compton and cold electron beam regime, the emittance ε of the electron beam is limited to be

γε<0.16\frac{(1+K^{2} / 2)^{3/2}}{\sqrt{N}K}λU

at the beam waist of the optical undulator of which the field is produced by focusing electromagnetic radiation such as a high-power molecular laser. Further discussion suggests that a high-quality, long-pulsed electron beam from UCSB's accelerator might promise FEL operation in the ultraviolet or shorter wavelength regions using a high-power CO2 laser undulator.
Crystal Structures of H-Pd5Ce and Pd5La and Their Electrical Resistivities at Low Temperatures
Authors: Itakura Masaru , Hisatsune Yoshimi , Sato Hiroshi , Kuwano Noriyuki , Oki Kensuke
Published: February 2005

The crystal structure of Pd5La was analyzed be powder X-ray diffraction and electron microscopy, and it was found that Pd5La is almost isomorphic with H-Pd5Ce. The electrical resistivity was examined for Pd5La, H-Pd5Ce and L-Pd5Ce in the range between 77 K and 300 K. The temperature dependence of resistivity suggested that H-Pd5Ce and L-Pd5Ce have a dense Kondo state.
The Generation of Hot Carriers in a Semiconductor Rod with a Notch
Authors: Kamigaki Tetsuya , Choe Il Yong , Akiba Yukio , Kurosu Tateki , Iida Masamori
Published: February 2005

The current transport mechanism of the SOGICON-type Ge device is studied. Current-voltage characteristics were measured by applying pulsed voltage. As the voltage was increased, there appeared first a sublinear region in the currentvoltage characteristics, and then current oscillation. From the present experiments, it was verified that the appearance of the sublinear region is ascribed to the generation of the hot carriers.
ESR Centers in Fused Quartz Exposed to Glow-Discharge Plasmas of Ar and H2
Authors: Endo Tamio , Taniguchi Shizuo , Inaba Ichiro , Katoh Masayuki , Hayashi Miyoshi , Sugiyama Koichi
Published: February 2005

Fused quartz was exposed to glow-discharge plasmas of Ar and H2 gases. The ESR centers, E', and the impurity-associated hyperfine structure (HF) centers were found in the uncovered quartz as well as in the quartz covered with a glass-plate having an absorption-edge E
e of 150 nm which prevented direct exposure to the plasmas. However, these centers were not found in the quartz covered with a glass-plate having an E
e of 220 nm. Both centers are created predominantly by UV-light of wavelengths between 150 and 220 nm radiated from the plasmas rather than by the plasma particles. It is suggested than the heating effect by the plasma particles on the directly exposed surface enhances the creation of the HF center.
Temperature Dependence of X1-X3 Splitting Energy in Lightly Doped GaP
Authors: Endo Tamio , Sawa Kazuhiro , Okino Yasushi , Itoh Nobuhiko , Sugiyama Koichi
Published: February 2005

The splitting energy δ between the X1-band with an effective mass m
1
* and the X3-band with m
2
*, and the effective mass ratio m
2
*/m
1
* for the conduction band of n-GaP were determined as a function of the temperature T by measuring the infrared absorption and fitting theoretical curves of the X1→X3 absorption band. As T rises, δ decreases as 0.349-6.83×10-5
T
2/(T+460) [eV], which can be explained by a faster shift of the upper X3-band than the lower X1-band toward the valence band. This empirical equation gives δ=0.316 eV at 773 K. The m
2
*/m
1
* increases, which indicates that the upward-bending of the X1-band has a stronger T-dependence than the X3-band.
Determination of the Dipole Moment of a Monolayer at the Air/Water Interface Using a Current-Measuring Technique
Authors: Iwamoto Mitsumasa , Majima Yutaka
Published: February 2005

A new technique for determining the dipole moment of the constituent molecules of a monolayer at the air/water interface has been developed. In this technique, two electrodes parallel to the water surface are used. One electrode (Electrode 2) is placed in the water and the other electrode (Electrode 1) is suspended in the air. Both electrodes are grounded. The displacement current due to the induced change on Electrode 1 is measured with the surface pressure-aria isotherm. Since the induced change is caused by the dipoles of the constituent molecules, the dipole moments of the molecules are determined. In this study, fatty acids are used as examples. A theoretical analysis for determining dipole moments by the present technique is also described.
Resolution of Scanning Acoustic Microscope in Sub-Surface Imaging
Authors: Ohno Masahiro
Published: February 2005

The resolution of the scanning acoustic microscope in sub-surface imaging is theoretically investigated. A formula for the point spread function is derived by assuming that a delta-functional point reflector exists inside a flat-topped solid specimen. The resolution is then evaluated using this point spread function and Rayleigh's criterion. Calculated results show that higher resolution can be obtained by detecting the shear waves than by detecting the longitudinal waves.
A Growth Analysis for Metalorganic Vapor Phase Epitaxy of GaAs
Authors: Doi Atsutoshi , Iwai Sohachi , Meguro Takashi , Namba Susumu
Published: February 2005

Metalorganic vapor phase epitaxy (MOVPE) of GaAs is analyzed using a new growth model. Surface reactions for trimethylgallium or triethylgallium adsorbed on the substrate surfaces are assumed to be the growth-rate-limiting steps. A catalytic effect is taken into account by assuming different decomposition rates for adsorbed alkyls on Ga- and As-terminated surfaces. The surface reactions are expressed in terms of reaction times and analyzed using a rate equation approach. Parameters in a rate equation are determined by fitting to the experimental results obtained by various methods: conventional MOVPE with and without laser irradiation, pulsed MOVPE, and laser atomic layer epitaxy. Good agreement between experiments and calculations in all growth methods shows the usefulness of the model.
Estimation of Non-Radiative Transition Rate in Tetracene-Doped Anthracene by Photoacoustic Spectroscopy
Authors: Umezu Ikurou , Ogawa Tsutomu , Arai Toshihiro
Published: February 2005

In order to investigate the impurity effect on non-radiative transition, we measured photoluminescence (PL), photoluminescence excitation (PLE) and photoacoustic (PA) spectra of tetracene-doped anthracene molecular crystals. We considered three radiative and non-radiative transitions to set up rate equations; from the anthracene exciton band to the ground state, from the anthracene exciton band to the tetracene impurity level and from the tetracene impurity level to the ground state. It was clarified from the results that the luminescence quantum efficiency due to anthracene decreases with increasing impurity concentration. Decrease of the quantum efficiency was discussed in terms of the change in transition matrix element.
Effect of Primary-Ion Current Density on Charge Compensation in SIMS Analysis of a Quartz Glass
Authors: Inoue Kazuyuki , Isogai Akio
Published: February 2005

In secondary ion mass spectrometry (SIMS) analysis of a quartz glass by means of negative ion bombardment, the effect of negative ion current density (J

i
) has been investigated. The results show that under lower J

i
(<20 µA/cm2), time is required to compensate for the surface charge and the time is inversely proportional to J

i
.
Silicon Oxide Projections Grown by Negative Corona Discharge
Authors: Nashimoto Keiichi
Published: February 2005

Products grown on a wire cathode by negative corona discharge in air containing a small amount of dimethylpolysiloxane vapor at atomospheric pressure were studied. After discharge for 120 minutes in dry air containing DMPS vapor, growth of amorphous silicon oxide projections and thin film was found on the tungsten wire cathode. The growth of the clusters of projections on the wire cathode occurred at certain intervals, and the location of the clusters corresponded to the figure of corona luminescence and the distribution of discharge current. The silicon oxide grown by negative discharge contained more OH and less oxygen than that grown by positive discharge. The growth mechanism of silicon oxide is explained as the plasma oxidation of DMPS vapor.
Low-Energy Electron Energy-Loss Peak Due to Excitation of the Surface State Associated with Dangling Bonds on Si(001)-2×1 Surface
Authors: Shigeta Yukichi
Published: February 2005

Low-energy electron energy-loss spectra (LEELS) from the Si(001)–2×1 surface were measured for some surface wave resonance (SWR) conditions: (1) The electron beam forms some surface waves associated with the fundamental lattice points (SWRb), and (2) the electron beam forms some surface waves with the 1/2-order superlattice rods (SWRs). In the LEELS for SWRb, the peak heights at 5, 8 and 11 eV in energy-loss value, ΔE, become slightly large. On the other hand, for SWRs, the peak heights at ΔE=1.5 and 8–9 eV are enhanced. The difference of LEELS for both SWR conditions reflects the difference in the thickness of the layers in which the electron beam propagates. It is discussed that the peak at ΔE=8–9 eV is due to excitation of a collective motion for the electrons in the dangling bonds out of the first plane of the surface atoms.
Dielectric Relaxation Measurements of Hydrated Powder at Subzero Temperatures by Time-Domain Reflectometry
Authors: Sakamoto Takeshi , Nakamura Haruki , Wada Akiyoshi
Published: February 2005

Time-domain reflectometry (TDR) was applied to dielectric relaxation measurements of a powder sample at subzero temperatures. A sample cell for the powder was designed so as to tolerate the packing pressure. Temperature reduction of the entire system, constructed from a copper block embedding the sample cell and a heat insulating box, was performed using liquid nitrogen. The performance of the system was demonstrated by the measurement of partially hydrated silica gel powder from -105degC to room temperature, and the temperature-dependent dynamic hydration structure was elucidated.
Analysis of Oxidation Enhanced and Retarded Diffusions and Growth of Oxidation Stacking Fault in Silicon
Authors: Yoshida Masayuki
Published: February 2005

In order to determine the fractional components of the interstitialcy mechanism for Sb, P and self-diffusions, d
I
Sb, d
I
P and d
I
sd, and the supersaturation ratios of vacancies and self-interstitials, s
V and s
I, from the experimental results of the oxidation-enhanced diffusion (OED) of P, oxidation-retarded diffusion (ORD) of Sb and growth of the interstitial-type stacking fault by oxidation (OSF), the equations of OED, ORD and OSF and of the special relation between s
V and s
I were solved simultaneously. The effect of the stacking fault energy upon growth of the OSF was taken into account in the OSF equation.
As the experimental results of OED, ORD and OSF did not satisfy their equations exactly, nine kinds of solutions were obtained and three of them were shown. The errors caused by the lack of exact satisfaction were shown. A d
I
sd much smaller than 0.5 was obtained.
On the Reactions of Quenched BaYCuO Powders with Various Materials
Authors: Komatsu Takayuki , Tanaka Osamu , Matusita Kazumasa , Takata Masasuke , Yamashita Tsutomu
Published: February 2005

The reactions of quenched BaYCuO powders (nominal composition: Ba2YCu3O7-x
) with various materials (Al2O3, ZrO2, MgO, TiO2, SrTiO3, quartz, silica glass, Si, Ge and Nb) at 900°C were examined using X-ray diffraction analyses and measurements of superconducting properties and the new crystalline phases formed by the reactions were determined. It was found that the quenched BaYCuO reacted strongly with these materials and barium element was contained in the reaction phases. The relation between the crystalline phases and superconducting properties for the annealed samples has been discussed.
Tunneling Spectroscopy of the 80 K Superconducting Phase of the Bi-Sr-Ca-Cu-O System
Authors: Ikuta Hiroshi , Maeda Atsutaka , Uchinokura Kunimitsu , Tanaka Shoji
Published: February 2005

The temperature dependence of the tunneling spectrum of the 80 K phase of the recently discovered high-temperature superconductor Bi-Sr-Ca-Cu-O system is reported. The shape of the tunneling spectrum and its temperature dependence are discussed.
Direct Preparation of Uniformly-Distributed YBa2Cu3O7-x Powders by Spray-Pyrolysis
Authors: Tohge Noboru , Tatsumisago Masahiro , Minami Tsutomu , Okuyama Kikuo , Adachi Motoaki , Kousaka Yasuo
Published: February 2005

Fine powders of the compound YBa2Cu3O7-x
have been prepared directly by the spray-pyrolysis of aqueous solutions of corresponding metal nitrates. The powders obtained in a temperature range of 900 to 1000°C were spherical and their diameters were uniformly distributed below 1 µm. The crystallinity of these powders was increased with increasing decomposition temperature; an orthorhombic single phase was indeed obtained at 1000°C. The sintered bodies from these powders showed the offset of superconducting transition at 84 K.
Preparation of Y-Ba-Cu-O Superconducting Tape by Atmospheric Plasma Spraying
Authors: Konaka Tsuneo , Sankawa Izumi , Matsuura Taketoshi , Higashi Tsuneto , Ishihara Koshi
Published: February 2005

Y-Ba-Cu-O superconducting tapes over 10 m long were prepared by an atmospheric plasma spraying method. The tapes were annealed at a maximum temperature of 900°C in an oxygen flow. The tapes consisted of a Y-Ba-Cu-O layer and a Ni alloy substrate. After annealing at 900°C, T
c onset and T
c offset of the tape were 94 K and 88 K, respectively. The critical current density at liquid nitrogen temperature was about 6 A/cm2 in the length range of 7.8 m. The superconductivity of the tapes was observed in the liquid nitrogen until it was bent to a curvature radius of 60 mm.
Application of Sintering Method to Prepare Perfectly Densified and Oriented CuInS2 Crystals
Authors: Miyauchi Takeshi , Yamamoto Nobuyuki , Higuchi Hideaki
Published: February 2005

Solid state reaction by sintering the finely powdered starting binary compounds, Cu2S and In2S3 was carried out to prepare homogeneous and stoichiometric CuInS2 crystals. Perfectly densified (with 100% theoretical density) and highly oriented CuInS2 crystals were obtained by sintering and annealing at 1050°C for 60 hours followed by slow cooling, using a pressed compact of the starting materials within a closely fitted carbon crucible. Appearance of the preferred (112) top surface of the crystal is utilized as a substrate crystal for homoepitaxial growth.
Superconducting Transitions of BiSrCaCu2Ox Quenched from High Temperatures
Authors: Ishida Takekazu , Sakuma Takashi
Published: February 2005

The BiSrCaCu2O
x
specimens have been quenched from various elevated temperatures (200°C ∼860°C) to liquid nitrogen. The X-ray diffraction study revealed that the crystalline structure of specimens is essentially tetragonal. We found that the lower T
c as well as the higher T
c vary remarkably but differently as a function of a quenching temperature T
q. We present evidence that the opposite T
c variation observed between 400°C and 700°C cannot be attributed to a microscopic interaction between two phases but might be inherent.
Low Temperature Preparation of As-Sputtered Superconducting YBaCuO Thin Films by Magnetron Sputtering
Authors: Miura Tadao , Terashima Yoshiaki , Sagoi Masayuki , Kubo Koichi
Published: February 2005

Superconducting YBa2Cu3O7-δ thin films were prepared on SrTiO3(100) planes at 560°C by rf multitarget magnetron sputtering without postannealing. The films were composed of two differently oriented grains with the c or a axis perpendicular to the surface. The preferential orientation could be controlled by the preparation condition. The transition to a superconducting state started at 90 K and zero resistance was achieved at 80 K for the films.
Preparation of 107 K Superconducting Thin Film in Bi-Sr-Ca-Cu-O System by Coevaporation
Authors: Yoshitake Tsutomu , Satoh Tetsuro , Kubo Yoshimi , Igarashi Hitoshi
Published: February 2005

Thin films of the Bi-Sr-Ca-Cu-O system were prepared on (100)MgO substrates by coevaporation of Bi2O3, Sr-Ca alloy and Cu metal, and the effects of film composition and annealing time on superconducting trasition temperatures were investigated. By post deposition annealing at 890°C for a long time, the films with relatively high-Ca compositions showed a superconducting transition with a zero-resistance T
c of 107 K. A high-Ca composition and long annealing time were necessary to prepare films with a zero-resistance T
c over 100 K.
In-Situ Raman Scattering Measurements of the Structural Phase Transition at High Temperatures in High Tc-Oxide YBa2Cu3Ox
Authors: Nishitani Ryusuke , Yoshida Naoki , Sasaki Yoshiro , Nishina Yuichiro
Published: February 2005

The structural phase transition from orthorhombic to tetragonal structure in the high-T
c superconductor YBa2Cu3O
x
has been studied by in-situ Raman scattering measurement at high temperatures. It is shown that the band in the 600 cm-1 region is enhanced in its intensity near the structural phase transition. Frequencies of several modes are measured as functions of temperature.
Characteristics of Ferroelectric Liquid Crystal Sandwiched between Drawn and Poled Polyvinylidene Fluoride Thin Films
Authors: Yoshino Katsumi , Ozaki Masanori , Hosono Yasuji , Ichihara Shoji
Published: February 2005

Homogeneous alignment of ferroelectric liquid crystal molecules in a cell has been successfully established utilizing thin drawn polyvinylidene fluoride (PVDF) film as coating material of an electrode. The effect of poling of the film and the electro-optical behaviour of this cell have also been clarified.