bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Observation of Phase Transformation Process by Energy-Dispersive X-Ray Diffractometry
Authors: Tohji Kazuyuki , Nishikawa Keiko , Murata Yoshitada
Published: November 2005

Energy-dispersive X-ray diffractometry has been applied to observe directly the phase transformation process (liquid→solid phase Ia→solid phase Ib→liquid) of carbon tetrachloride and the premelting process of benzene. Dynamic changes of diffraction patterns in transformation processes have been observed.
Substrate Bias Effect on Ion-Implanted GaAs MESFETs
Authors: Kitahara Kuninori , Nakai Kenya , Shibatomi Akihiro , Ohkawa Shinji
Published: November 2005

Decrease in drain current caused by negative bias on the substrate (substrate bias effect) is observed in MESFETs fabricated from ion-implanted GaAs. Illumination of IR light enhances the effect in a similar manner to VPE GaAs. From photoconductivity measurement on the FIT, the substrate bias effect is found to be dominated by the same deep levels as those located in the semi-insulating GaAs substrate.
Incorporation of Oxygen into Silicon during Pulsed-Laser Irradiation
Authors: Hoh Koichiro , Koyama Hiroshi , Uda Keiichiro , Miura Yoshio
Published: November 2005

Evidence for the oxygen incorporation into silicon during surface melting by the pulsed-laser irradiation is presented. SIMS measurement of 18O in Si samples which were laser-irradiated in 18O2 atmosphere shows that 18O is introduced in Si with the maximum concentration 7×1020 cm-3 and the penetration depth 1.4 µm. The incorporation of 18O is blocked when the Si surface is covered with SiO2.
Properties of InP Films Grown by Organometallic VPE Method
Authors: Fukui Takashi , Horikoshi Yoshiji
Published: November 2005

Vapor phase epitaxial growth of InP was carried out using triethylindium and PH3 on semi-insulating InP substrate. Triethylindium and PH3 were mixed after they were introduced to the reactor, which reduced the formation of an intermediate compond and resulted in successful growth of high quality InP films under normal pressure. The growth rate was as high as 4∼5 µm per hour. The best mobility obtained was 36300 cm2/V·s at 77 K. The photoluminescence intensities are comparable to those of LPE and LEC crystals of equivalent doping level.
Thermal Nitridation of InP
Authors: Yamaguchi Masafumi
Published: November 2005

Thin uniform InP nitride films less than 1000 Å have been obtained on InP substrates by direct thermal reaction with high purity ammonia gas at temperatures ranging from 530 to 560°C. From the electron diffraction measurements, it is found that the nitride films are composed of polycrystalline indium nitride and phosphorous nitride. Resistivities at room temperature of the thermally grown nitride films range from 10
s+ to 10
s+ Q·cm. Resistivities decrease within crease in nitridation time and temperature above 560°C, which are mainly caused by thermal decomposition of indium nitride.
Undercutting Phenomena in Al Plasma Etching
Authors: Oda Masatoshi , Hirata Kazuo
Published: November 2005

Undercutting phenomena in Al plasma etching were investigated. Photoresist, SiO2 and Si3N4 were used for etching masks. PSG, Si(100), Si3N4 and Al2O3 were used for underlying layers. In various combinations of etching masks and underlying layers, only photoresist mask exhibits no undercutting. However, even in this case, undercutting occurs according to over-etching time and pattern density. An hypothesis that a film observed on an Al pattern sidewall acts as a protection against undercutting was proposed. Undercutting phenomena were easily explained by this hypothesis.
DLTS Study of Cr Trap Density in Thermally Converted Semi-Insulating GaAs
Authors: Kumagai Osamu , Kasahara Jiro , Kaneko Kunio
Published: November 2005

Deep traps in Cr-doped semi-insulating GaAs annealed under various arsenic partial pressureswere investigated by DLTS and in-depth profiles of Cr trap density were obtained. The profiles show out-diffusion of Cr traps. Near the surface region, however, the electrically active Cr trap density was about ten times lower than the Cr atomic density.
Observation of Non-Circular Cross-Section for q=1 Magnetic Surface in Very Low-q Discharge (qa\lesssim2) of DIVA Tokamak
Authors: Yamamoto Shin , Sengoku Seio , Matsuda Tosiaki , Matsumoto Hiroshi , Ohasa Kazumi , Odajima Kazuo , Kimura Haruyuki , Yamauchi Toshihiko , Kumagai Katsuaki , Sugie Tatsuo , Kasai Satoshi , Maeda Hikosuke , Shimomura Yasuo
Published: November 2005

Non-circular cross-section forq=1 magnetic surfaces were experimentally shown in stable very low-qdischarge (qa\lesssim2;qais the safety factor at the plasma surface) of DIVA tokamak with and without a divertor. Heat flux to the first wall due to the sawtooth disruption in low-qdischarge will become a serious problem in future large tokamak if sawtooth disruption cannot be suppressed.
Dielectric Dispersion of Triglycine Sulfate (TGS) Powders
Authors: Motegi Hiroshi , Ibaraki Koichi , Nakamura Eiji
Published: November 2005

The complex dielectric constant of TGS powders 74∼105 µm in particle size has been measured between 77 K and 340 K in the frequency range from 10 Hz to 105 Hz. Four types of dielectric relaxations are found in the ferroelectric phase. The relaxation frequencies obey the formula, f
r=f
oexp
(-U/k
T). The values of f
o and U are determined to be 1×108 Hz and 0.33 eV, 4×1012 Hz and 0.35 eV, 9×1013 Hz and 0.33 eV, and 2×108 Hz and 0.06 eV, respectively, which are quite different from those of multidomain single crystals.
Comparison of Efficiencies of Electrostatic Wave-Excitation by Far-Infrared Laser Beam and Ion Beam
Authors: Tsukishima Takashige
Published: November 2005

Two methods for driving electrostatic waves in the magnetized, high temperature plasmas are compared theoretically for driven scattering measurements, i.e., one with a power-modulated far-infrared (FIR) laser beam and the other with a density modulated ion beam. The coupling coefficients relating the powers of these driving beams to the amplitudes of the excited wavesare derived. The FIR beam is shown to be more efficient than the ion beam. It is also shown that the incident FIR power required for the driven scattering can be drastically reduced when it is chosen equal to the driving FIR power for wave excitation.
Diffusion of Impurities in the Semiconductor Melt III. Experimental Determination of Thickness of the Solute Diffusion Layer in the Melting Process
Authors: Kodera Hiroshi , Iida Shinya , Tauchi Shoji
Published: November 2005

The thickness of the solute diffusion layer in the melting process is determined through various experiments which give some informations about the impurity distribution. Experimental results are analyzed using the method of analysis reported in the preceding paper (Japan. J. Appl. Phys. 2 (1963) 220). The existence of the solute diffusion layer in the melting process is confirmed for both germanium and silicon. The thickness of the solute diffusion layer is estimated to be 0.4 mm for germanium and 1 mm for silicon.
Measurement of Electron Temperature of a Plasma by Microwave Method
Authors: Sakamoto Yūichi , Miyoshi Syōichi
Published: November 2005

Thermal radiation in 9000 Mc/sec region emitted from a steady plasma without external magnetic field is received by a microwave horn antenna and measured with an eletcric field meter.
The electron temperature is obtained, taking by antenna factor and the absorptivity of the plasma into consideration. Langmuir probe measurements are also made. Both results show good agreement.
A method for measuring the absorptivity of a plasma in the far field by the use of antenna is investigated both theoretically and experimentally.
Cylindrical Mode of Oscillation in a Ruby Optical Maser
Authors: Yajima Tatsuo , Shimizu Fujio , Shimoda Koichi
Published: November 2005

A particular type of mode in optical maser oscillation was obtained with a ruby rod having parallel-plate resonator with a central hole in one of the reflector coatings. The oscillation has occurred in a region of cylindrical pipe distributed coaxially with the ruby rod. Around the periphery of the active region of annular-shape on the end-surface of the rod, a standing wave of the azimuthal mode number of about 225±10 has been formed with a good spatial coherence. The far-field pattern of annular-shape accompanied by fine radial fringes was observed, and it was well interpreted on the basis of Fraunhofer diffraction theory. The reason for the occurrence of particular azimuthal mode number was attributed to the slightly concave nature of the reflectors. The experimental results on the associated relaxation oscillation of a particular type are briefly described.
Improved High-Temperature Microscope and Its Metallurgical Applications
Authors: Taoka Tadami , Ohkohchi Makoto
Published: November 2005

A high-temperature microscope has been designed and constructed for the observations of thermal transition phenomena.
By the use of a new mechanical stage, rotatable quartz window and micro-furnaces, the dynamic phenomena can be continuously observed on the area 10 mm in diameter on a specimen surface. Moreover, the microscope enabled an uninterrupted observations for more than 6 minutes at 1200°C in low pressure of hydrogen. Three types of micro-furnaces were designed for the purpose of heat-treatment and observation below 1550°C for specimens of different shapes. Using this microscope, structure-changes accompanied by grain growth have been successively observed for silicon-iron. The resultant resolution was 1–2 µ on photographs at 1100°C.
Voltage Programming of Radio Frequency Accelerations in an Alternating Gradient Proton Synchrotron
Authors: Huke Kazuo , Iwata Giiti
Published: November 2005

The condition that RF buckets of radio frequency accelerations in synchrotrons have always no empty space by virtue of the adiabatic damping of phase oscillations, is obtained by calculating the action integral of phase oscillations. This analysis is applied to make an RF voltage programming which minimizes the maximum RF voltage and RF powers for the 12 Bev AG proton synchrotron of a high repetition rate. The behaviors of phase oscillations in the neighbourhood of the transition energy in this scheme of RF accelerations are also analysed and discussed.
Zündgrenzen des Kohlenwasserstoff-Luft-Gemisches
Authors: Terao Kunio , Takahashi Shigeru , Miyazaki Seizaburo
Published: November 2005

It has been already reported by other investigators that generally the ignition limits for a hydrocarbon-air mixture consist of two regions, namely region of cool flame and of hot ignition, respectively. The so-called second-stage ignition between these two regions has an inverse S-form in a pressure-temperature diagramm. These ignition limits were hitherto explained by means of the theory of chain reaction. In this investigation, however, by measuring the probability of the hot ignition and of the cool flame reaction behind reflected shock waves, the same ignition limits for a n-heptane-air mixture were obtained. Following this observation, it is presumed that generally many different reactions can take place in the ignition and one of them appears if its probability is great and its developing time short enough. Thus, it is suggested, that the existence of such ignition limits does not prove that some chain reaction take place, but that the theory of gas kinetics is adequate to explain the observed phenomena.
Interpretation of Rings in the Far-Field Pattern of Optical Masers
Authors: Shimoda Koichi
Published: November 2005

It has been believed that the interference rings in the far-field pattern of the radiation of an optical maser is due to the oscillations in off-axis modes. It is shown here that the rings in the far-field pattern are produced by the interference of radiations from atoms in a filamentary region of oscillation with an axial mode. The angle of maximum intensity for the m-th order interference is approximated by µθ
m
=(µλ/L)½(m+1/2)½, m=1, 2, … and the zero-th order appears in a direction θ0=0. Here µ is the index of refraction and L is the length of the maser. The result agrees fairly well with experimental values obtained from ruby masers.
Electrodeposited Nickel-Iron Thin Films
Authors: Uehara Yasuo
Published: November 2005

Magnetic properties of nickel-iron thin films electrodeposited onto copper substrates have been experimentally studied. (1) The coercive force H
c takes the minimum value at the film composition about 81.5Ni–18.5Fe. The squareness ratio B
r/B
s of Fe-rich films is very close to 1, while that of Ni-rich films decreases with an increase of nickel concentration. (2) The coercive force H
c is proportional to d
-n
for the 71∼88%Ni–Fe films, 1200 to 14000 Å thick. The exponent n takes a constant value in Fe-rich regions, while the value gradually decreases with an increase of nickel concentration passing through 81.5Ni–18.5Fe. (3) The uniaxial anisotropy is remarkably affected by the geometrical states of the surface of the substrates.
The relation between the composition of nickel-iron films and the depositing conditions has also been studied. The depositing conditions to prepare the film having a minimum H
c are described.
Transverse Instabilities in Solid State Plasmas under Steady Electric and Magnetic Fields
Authors: Misawa Toshio
Published: November 2005

Effects of a dc electric field on the behavior of circularly polarized, low frequency waves in infinite plasmas under a dc magnetic field in which densities of mobile carriers of different sign of charge are not equal are investigated. The wave shows spatial growth and instability. Collisions are beneficial to these. According to Sturrock's criterion, the spatially growing waves can not be used for amplification and the instability leads to spontaneous oscillation. The dielectric constant tensor is calculated for a quite general case of arbitrary directions of wave propagation and dc electric field by the hydrodynamic approximation and for the case of parallel electric and magnetic fields but arbitrary direction of propagation by the kinetic theory using a completely degenerate steady state distribution and a simple collision term. By using the dielectric constant tensor thus obtained, it is found that in Bi-like material at lower temperatures, the inclined field enhances instability especially of inclined waves and the hydrodynamic approximation is a fairly good approximation.
An Interpretation of Electron Paramagnetic Resonance Spectra of Irradiated Polyethylene
Authors: Kashiwabara Hisatsugu
Published: November 2005

A short review on the behaviour of the free radicals produced in irradiated polyethylene is presented and a consistent interpretation of the trapping of the free radicals in polymer is proposed in connection with the morphological fact of polymer crystals. All the observed behaviour of the stable free radicals of seven-line pattern can be interpreted by assuming that the radicals are trapped in the “pseudo-crystalline region” in polyethylene (probably the folding part of crystal lamella).
BaTiO3 Single Crystals Subjected to Mechanical Impulses
Authors: Toyoda Hiroo , Shibata Hiroyuki
Published: November 2005

Etching with fusion of NaOH delineates dislocations in the BaTiO3 crystals and by this use, the behavior of mechanically-treated crystal is investigated. When the crystal is subjected to a pointed impulse, a characteristic a-domain pattern appears near the point of contact. Annealing the mechanically-shocked crystal above 1000°C removes the pattern, while two parallel columns or parallel crosses of dislocation etch pits appear. It is supposed that the elastic strain may be released by taking place of a plastic flow upon heating. The part surrounded by parallel columns exhibits an anomalous birefringence, almost unchanged across the Curie point.
Observation of the Recombination Radiation from Silicon p-n Junction
Authors: Uchida Ichizo
Published: November 2005

The recombination radiation from forward biased p-n junctions of silicon is visualized by use of an infrared image converter tube. It is found from the pattern of the radiation at the junctions that the diffusion length of minority carriers is structure sensitive, especially at 80°K. The life time estimated from the decay time of the pulsed radiation agrees fairly well with that measured by the photoconductivity decay method.
Quantitätseffekt des elektrischen Funkens auf die Funkenzündung in Gasen
Authors: Terao Kunio , Shimoda Kunihiko , Nakano Hiroshi
Published: November 2005

The effect of the gap-length on the ignition of gas mixture was investigated, taking account of the ignition probability, which was obtained from the statistical analysis of the fluctuation of the induction period of ignition. The results show that the proportional factor of ignition probability, which is independent of the activation energy and the temperature of mixture, increases as the gap-length increases. Thus the influence of the gap-length on the ignition can be explained by the quantity effect of the spark. No cooling effect of the electrodes was observed.
Impedance Method for Measuring High Electron Density and Electron Collision Frequency in a Gaseous Plasma Column
Authors: Takeda Susumu
Published: November 2005

The impedance method is extended to deduce simple and convenient formulas for measuring electron density higher than the critical value corresponding to the plasma resonance. The determination of both the electron density and the collision frequency in transient plasmas is possible by simultaneously recording two detected microwave signals. The electron density range measurable covers from 1×1013 cm-3 to 5×1010 cm-3, at a frequency of 9000 mc/sec.
Dielectric Constant of PbTe
Authors: Kanai Yasuo , Shohno Katsufusa
Published: November 2005

The low frequency dielectric constant of PbTe was determined by measuring the barrier capacitances of PbTe abrupt junctions at about 100 kc/s and low temperatures. The junctions were made by alloying In to p-type base crystals or Ag-Te alloy to n-type crystals. The donor or acceptor density in crystals was controlled by heat treatment to range from 1.5×1017 to 8.0×1018 cm-3. As the low frequency dielectric constant of PbTe a value of 400 was obtained, which is approximately constant in the temperature range from 4.2 to 130°K and in the frequency range from 10 to 150 kc/s.
This high value of dielectric constant is sufficient to explain the large value of carrier mobility in PbTe at low temperatures.
Preparation and Properties of Vacuum-deposited Germanium Thin Films
Authors: Sakai Yoshio , Takahashi Kiyoshi
Published: November 2005

Germanium thin films have been prepared on hot Pyrex glass, mica, and single-crystal germanium substrates by thermal evaporation in high vacuum. The electrical characteristics of the prepared films are most sensitive to the substrate temperature. Excellent germanium film can be obtained at substrate temperatures between 450°C and 550°C. Their crystalline structures were examined by electron diffraction and the electrical characteristics were measured.
It was found that N-type germanium film can be prepared if germanium and phosphorus or arsenic are evaporated at the same time. The properties of such N-type films are described, and the doping process with donor impurity is discussed briefly.
The properties of a P-N junction photocell, a tunnel diode, and a piezoresistive element thus prepared are described.
Flow Properties of Powder
Authors: Taneya Shin'ichi
Published: November 2005

A study on flow of powder is made with the aid of a double-cylinder type viscometer. Rotating the outer cylinder, the torque exerted on the inner cylinder and the amplitude of torque fluctuation are measured. Two types of flow are observed: theparticle-flowin which every powder particle moves as an independent unit, and theblock-flow, in which the powder particles agglomerate in blocks. In some kinds of powder the above two types of flow can take place simultaneously. The amplitude of the torque fluctuation is found to be smaller in those kinds of powder which are cohesive.
Growth and Structure of Si Oxide Films on Si Surface
Authors: Edagawa Hiroshi , Morita Yoshinori , Maekawa Shun-ichi , Inuishi Yoshio
Published: November 2005

The oxidation on Si surface were carried out by
(i) the thermal oxidation in dry and wet oxidizing gases
(ii) the thermal decomposition of ethyltriethoxysilane
(iii) the vacuum evaporation of SiO and quartz.
The growth rates of thermal oxidation on Si surface have been studied both by interference fringe and by microbalance methods. It was found that the thermal oxidation growth curves as a function of time follow the parabolic law regardless of the kinds of oxidizing gases such as saturated water vapor etc.
Crystal structure of the oxide films produced by various oxidation methods have been analysed by the electron diffraction method. According to the results of the electron diffraction, optical absorption and photoresponse measurements using step etching procedures for various oxide films, the cause of the n-type conversion due to oxidation on Si surface is discussed.
Observation of Plasma Density Waves in n-InSb in Transverse Magnetic Fields
Authors: Toda Minoru
Published: November 2005

Electron-hole plasma density oscillations in n-InSb have been investigated in transverse magnetic fields using a microwave probe technique. Experiments were done at 77°K and 210°K, using single pulses. The damped oscillations observed at 210°K have been identified as traveling density waves with frequencies ranging from 2 Mc–13 Mc, depending on the magnetic field intensity. The oscillations observed at 77°K were growing waves. The oscillations were identified as standing waves both in the longitudinal and transverse directions. Their frequency ranged from 20 Mc to 50 Mc depending on the magnetic field and the current strength. Both types of oscillations were seen in breakdown region of the current strength. Both types of oscillations were seen in breakdown region of the current-voltage curve. Incoherent waves, similar to noise, were observed above certain critical magnetic fields.
Linearity Characteristics of Multiplier Phototubes
Authors: Nonaka Mamoru , Kashima Takeo
Published: November 2005

In most cases, multiplier phototubes are used on the assumption that the anode current is strictly proportional to the incident light flux, that is, the departure from linear response is assumed to be negligible over a wide range. However, the departure is never negligible in these tubes and varies according to the operating condition. The linearity characteristics of multiplier phototubes with side-window type of photo-cathodes have been investigated in this work, and the following results obtained. The departure from linear response depends on the wavelength of incident light and the supply voltage between the anode and the photocathode, and becomes large for flux incident upon the edges of the photocathode. But the state of polarisation of incident light does not affect the linearity.
Modelocking of Semiconductor Laser Diodes
Authors: Haus H. A.
Published: November 2005

The history of modelocking of the semiconductor laser is reviewed. The theory of modelocking as it relates to the semiconductor laser diode system is developed and discussed. Experiments on semiconductor lasers at MIT and the Bell Laboratories under both active and passive modelocking conditions are described.
The Physics of the Retrograde Motion of the Electric Arc
Authors: Drouet Michel G.
Published: November 2005

The retrograde motion of the cathodic arc attachment point in a transverse magnetic field is examined and is attributed to the asymmetrical confinement of the cathode spot plasma which results from the asymmetrical combination of the self and applied magnetic fields. This confinement of the cathodic vapor on the retrograde side of the microspot enhances the electron emission on that side and thus favors the observed retrograde motion of the arc attachment point. The model is shown to be consistent with a number of reported features of the retrograde motion and the cathode spot.
Migration Energy of Vacancies in Bismuth
Authors: Otake Shuichi , Ishii Yoshinobu , Matsuno Naoshi
Published: November 2005

Annealing studies on quenched bismuth have been carried out using electrical resistivity measurements in the temperature range from 77 K to 380 K. A recovery stage is observed between 230 K and 310 K. This stage must be caused by annihilation of vacancies. The migration energy of a vacancy, 0.30 eV, is determined by the slope change method in this stage. The activation energy of self-diffusion is estimated using a similar formula for typical metals and is found to be 0.66 eV (15.2 kcal/mol). The ratio between the activation energy of self-diffusion and the melting temperature is 27.9 cal/mol. This value is slightly lower than that for typical metals.
Dendritic Structures Developed on Fe-FeSi Eutectic Thin Films below the Eutectic Point
Authors: Asahi Nobuo
Published: November 2005

When Fe-FeSi eutectic thin films are maintained at temperatures below the eutectic point for various periods of time, and then cooled at suitable rates, dendritic structures appear on the specimen surfaces. According to electron microscopic observation, the dendritic structures obtained in such a way are quite similar to those obtained at the eutectic point. Considering that dendritic growth usually takes place when a melt is supercooled, it is concluded from the above fact that the eutectic point of Fe-FeSi eutectic thin film is lower than that of the bulk eutectic alloy.
The nature of this phenomenon was studied to see whether it could be explained by existing theory.
Thermoluminescence of KBr: Tl around Room Temperature
Authors: Joshi R. V. , Chaudhari R. T.
Published: November 2005

Thermal glow curves of KBr: Tl phosphors were investigated after irradiation with ultraviolet light or X-rays at room temperature. It was found that the specimens exhibited a single glow peak in the temperature range of 340–370 K, the position of the maximum of which depended on the history of the sample. Present work included the effects on the thermoluminescent characteristics of the phosphor when subjected to various thermal and/or mechanical treatments. It is proposed that the Tl+ ion-anion vacancy pair situated in the perfect region of the lattice is responsible for the peak at 370 K. Shift in the peak position to lower temperature side is attributed to the Tl+ ion-anion vacancy pair in the distorted region of the lattice, the distortion being caused by the vacancy cluster in the neighbourhood of the pair.
Electrical and Optical Studies in Gallium Antimonide
Authors: Nakashima Kenshiro
Published: November 2005

Hall effect, photoluminescence, and photoconductivity measurements on residual acceptors in GaSb grown by the Bridgman method, are presented and discussed with emphasis on the determination of energy level positions. The effect of thermal annealing or Li-diffusion on the behavior of the energy levels of residual acceptors is investigated to ascertain the nature of doubly-ionizable acceptors. Photoluminescence data on the Au-GaSb Schottky barrier give additional results confirming that the rediual acceptor is doubly ionizable. Direct evidence for the defect configuration is also presented.
Simple Analytical Explanation of Transient Switching Process in Amorphous Semiconductor, As30Te48Ge10Si12
Authors: Miyazono Toru , Iida Masamori
Published: November 2005

The transient switching behavior of the amorphous semiconductor As30Te48Ge10Si12 is investigated both theoretically and experimentally. A number of transient characteristics can be explained by the transient switching model proposed, based on the concept of space-charge overlapping for the pure electronic process. It is shown experimentally that the mobility has a voltage dependence, when the applied voltage is higher than the threshold value; µn+µp=6.8×10-9 V-1 exp
(a
V) (m2V-1s-1), a=1.9 exp
(-2.1×106
L) (V-1). The experimentally estimated ratio of the mobilities is 27.8. It is shown experimentally that injection both of electrons and holes is necessary to initiate the switching action and that injected carriers contribute to the current flow as space-charge limited current in the OFF state.
Capacitive Humidity Element Using Polystyrene Thin Films Formed by Plasma Polymerization
Authors: Takeda Shinnichi
Published: November 2005

Polystyrene(PS) thin films used as a material for absorbing water vapor were formed by plasma polymerization, providing chemical resistance and rigidity due to the network structure of the polymer. An Au thin film 120 Å thick was deposited on the surface of the PS thin film, sufficient to transport water vapor. Parallel plate capacitors were made in the form Au-PS-Al, and were used as capacitive humidity elements. Elements with a PS film thickness of about 2000 Å had a response time of 1 to 2 seconds, and PS thin film capacitors with these humidity characteristics are suitable for use as fast-response humidity elements.
Attachment of Low-Energy Electrons to O2-Molecules in Ar-N2-O2 Gaseous Mixtures
Authors: Sugiyama Tadashi
Published: November 2005

The attachment coefficient α of low-energy electrons to oxygen molecules in Ar-N2-O2 ternary gas mixtures of various composition was measured at room temperature for various values of electron characteristic energy ε
k below 1 eV, using an electron-pulse ionization chamber. Under a constant value of ε
k, the observed “reduced” rate of attachment αw/p(O2), where w denotes the drift velocity of electrons and p(O2) the oxygen partial pressure, showed a broad maximum and a following shallow minimum when plotted against p(Ar) in the region where p(Ar) became comparable to p(N2), whereas it increased faster than linearly when plotted against p(N2) again in the region where p(N2)∼p(Ar). These experimental results show, as expected, that the shape of the electron energy distribution is different for gases with different mixing ratios of the component gases even for the same value of ε
k.
Study of Anodic Film Growth on GaAs and Bi2Te3 by in situ Photoacoustic Technique
Authors: Yamagishi Chouho , Moritani Akihiro , Nakai Junkichi
Published: November 2005

Anodic film growth on GaAs and Bi2Te3 during the anodization process was observed with an in situ photoacoustic technique. It was shown that the time dependence of the normalized change in the photoacoustic signal reflects the anodic film growth on GaAs and Bi2Te3. The photoacoustic technique is complementary to the differential reflectance technique; the measured quantity is a change in transmittance of the electrolyte-anodic film-substrate system for the former case and a change in reflectance of the three phase system for the latter case. Experimental results obtained in the photoacoustic measurements are discussed in relation to those previously obtained in the differential reflectance and in situ ellipsometry measurements.
Measurement of the Energy Distributions of Secondary Ions from Pure Metals and Alloys
Authors: Okutani Tsuyoshi , Shimizu Ryuichi
Published: November 2005

Precise measurement of the energy distribution of secondary ions was attempted in order to study the correlation with surface properties. The experiments revealed that the peak of the energy distribution shifts towards the lower energy as the partial pressure of oxygen becomes higher for both Al and Mg under Ar+ ion bombardment.
The measurement was then extended to Ni-W and Cu-Ni alloy samples to see whether any difference between the peaks of secondary ions of constituent atoms could be found, the same as those of sputtered Ni- and W-atoms from Ni-W alloy reported by Oechsner et al. The results suggest that no substantial difference exists in the energy distribution of secondary ions of constituent atoms for both the Ni-W and Cu-Ni alloys even though the peak positions of the secondary ions of constituent atoms with higher sublimation energy are always slightly higher.
High Magnification Observation of Magnetic Domains by Means of a High Voltage Scanning Electron Microscope
Authors: Tsuno Katsushige , Ueno Katsuyoshi , Harada Yoshiyasu
Published: November 2005

The resolution of a magnetic domain image in the backscattered electron mode of a high voltage scanning electron microscope was determined from the diameter of an electron probe. The probe diameter was reduced from 2 µm to 0.06 µm by attaching an objective lens whose magnetic field around the specimen was shielded. The maximum magnification giving a clear image was improved from 100 to 3000× by attaching the shielded objective lens. The shape of zig-zag domains (about 1.9 µm spacing) appearing on the crossed region between the in-plane domain and the stripe domain of amorphous 80%Fe-8%Si-12%B ribbon was clearly resolved by using the shielded objective lens.
Crystal Characterization by Magnetoplasma Resonance in N-Type InSb
Authors: Tsukioka Kunio
Published: November 2005

Magnetoplasma resonance (MPR) studies have been carried out on high purity n-InSb at 23 GHz over the temperature range 50–130 K to obtain more accurate and detailed crystal characterization. The mobility values estimated from MPR, µMPR, were found to be lower than the corresponding DC mobility, µDC. From the theoretical estimate of µMPR and the correlation between µMPR and the gradient of transverse magnetoresistance with respect to the magnetic field, it can be concluded that the upper limit of µMPR (∼0.5 µDC) is restricted by the energy dependence of τ and further µMPR reduction is mainly due to the spatial fluctuation of carrier concentration. This interpretation is supported by the feature of the temperature dependence of µMPR. The effects of low temperature heat treatment on n and µMPR are also discussed.
Diffraction Effect due to Optical Noise Sources in a Glass Laser System
Authors: Kuroda Junji , Kato Yoshiaki
Published: November 2005

Diffraction patterns caused by optical noise sources have severe detrimental effects on high power glass laser systems. We have experimentally and analytically studied the diffraction patterns caused by phase perturbation as well as by intensity perturbation and have obtained them at various locations before and after spatial filtering. Based on these results, the maximum size of noise sources that are allowable in glass laser systems have been determined.
Spontaneous Recombination, Gain and Refractive Index Variation for 1.6 µm Wavelength InGaAsP/InP Lasers
Authors: Stubkjaer Kristian , Asada Masahiro , Arai Shigehisa , Suematsu Yasuharu
Published: November 2005

The spontaneous carrier lifetime τs was measured as a function of temperature for 1.6 µm wavelength InGaAsP/InP lasers. As a good approximation 1/τs∝I
th
1/2, where I
th is the threshold current, in the temperature region from 140 K to 320 K. The measured lifetime, given by τs=1/(B
eff
N), where N is the carrier density, resulted in the effective recombination coefficient B
eff=1 –2×10-10 cm3s-1 at room temperature.
Gain spectra were measured for different temperatures. The gradient of room temperature peak gain with respect to carrier density was determined to be 1.2×10-16 cm2. At 140 K this gradient as well as the curvature of the gain spectra showed an ∼10 times increase.
The refractive index variation with carrier density was also obtained at different temperatures.
Control of Toroidal Expansion of a High Beta Plasma Column in a Pinch Tokamak by Programmed Pulsed Vertical Field
Authors: Nagata Akiyoshi , Yamaguchi Satarou , Hirano Kei-ichi
Published: November 2005

Dynamics of high beta toroidal pinch plasmas in the major radius plane are calculated after a simple model and compared with experimental results of STP-2 screw pinch1) which is operated under the condition of T
e≃20 eV and n
e≃1.2×1015/cm3. It is demonstrated that the calculation agrees with the experimental results in the early phase of the discharge where the plasma keeps a high beta value (poloidal βp≃3) while the discrepancy between them begins to grow after 8 µs from the start of the main discharge because the βp value decreases considerably. In order not to deviate the plasma column from the center of the discharge tube a concept of the effective dissipative force generated by a proper programming of the pulsed vertical field is introduced. It is demonstrated that this concept is useful to keep the shock-heated high beta plasma in the center of the discharge tube since unfavorable toroidal expansion disappears completely in a few microseconds by a proper programming of the pulsed vertical field.
Plasma Formation in a Neutral Gas by a Short-Pulsed, High-Current Electron Beam
Authors: Ono Kouichi
Published: November 2005

Numerical investigations were made of plasma formation in the interaction of an electron beam (600 kV, 10 kA peak, 3 ns FWHM) with a neutral gas (0.8–8 Torr Ar). In the numerical model, the beam is assumed to be a rigid cylindrical rod, and the plasma formation processes are assumed as follows: initially, high-energy beam-electron impact ionizes the gas, and the space-charge electric field of the beam is neutralized by the ions produced. Then, the beam-induced axial electric field becomes dominant, causes gas breakdown, and drives the plasma current. A plasma of density ∼1014 cm-3 and temperature ∼5 eV is produced in the beam-gas interaction. The numerical results approximately agree with the experimental ones for the plasma current and for the singly-ionized line emission.
Measurement of the Virtual Mass of a Cylinder Using a Resonance Tube
Authors: Matsuzawa Kiichiro , Hasegawa Takahi , Ochi Masayuki
Published: November 2005

A new acoustical method for measuring the virtual mass is described in this paper. The fundamental frequency f
0 of a rectangular tube with both ends closed is reduced to f
0-f by the introduction of a cylinder at the center of the tube; the cylinder is inserted in the tube perpendicularly through a wall of the tube and reaches the opposite wall. A theoretical formula for the inertia coefficient (the ratio of the additionally induced mass to the mass of air displaced by the cylinder) is obtained as L=(f/f
0)/(S/S
0)-1, where S and S
0 are the areas of the cross sections of the cylinder and the tube, respectively, and two-dimensional motion of the air is assumed. Experiments were made using a tube of f
0=247 Hz and several circular and elliptic cylinders of f=0.6 ∼2.5 Hz. The values of L thus obtained are in good agreement (within 10%) with the theoretical values which are well known in hydrodynamics.
Peierls Phase Transition
Authors: Kagoshima Seiichi
Published: November 2005

A description is given of the present status of studies on the Peierls transition, which is a metal-insulator transition characteristic of an electronically one-dimensional system. Fundamental properties of a one-dimensional electron system are discussed and the concept of charge-density wave is explained. Physical properties of TTF-TCNQ and its family (TSeF-TCNQ, HMTTF-TCNQ, HMTSF-TCNQ, TMTSF-DMTCNQ and NMP-TCNQ) are described in relation to the Peierls transition, and brief descriptions are given of other one-dimensional conductors, MX3 (M=Ta, Nb; X=S, Se) and K2Pt(CN)4Br0.3·3H2O.
Solutions in Viscous Constantly-Inclined Magnetohydrodynamics
Authors: Barron R. M. , Chandna O. P. , Garg M. R.
Published: November 2005

Solutions are obtained for spiral flows with circular (constantly-inclined) magnetic lines and for circular flows with spiral magnetic lines. Furthermore, it is established that the only possible constantly-inclined flows with radial magnetic lines or radial streamlines are those in which the streamlines and magnetic lines are orthogonal.
Model for Localized States Distribution and Light Dependent Effects in Amorphous Silicon Solar Cells
Authors: Miyamoto Hiroshi , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

The localized state density for amorphous Si (a·Si) can be reasonably approximated by a U-shaped hyperbolic function for the theoretical analysis of the potential profile in the depletion layer of a·Si Schottky barrier solar cells. The photocurrent dependence on the width of the depletion layer has been theoretically analyzed with emphasis on the effect of minority carrier recombination in the depletion layer and the shrinkage of the depletion width under sunlight due to hole trapping. The detailed analysis shows that the minority carrier diffusion length L
p is about 0.15 µm and the optimum width of the undoped layer in Schottky barrier solar cells is in the range of 0.2–0.44 µm for the minimum density of gap states of 1017–1016 cm-3eV-1, respectively.
Characterization of Graphites by Positron Lifetimes
Authors: Iwata Tadao , Fukushima Hiroshi , Shimotomai Michio , Doyama Masao
Published: November 2005

Positron lifetimes have been measured in different types of graphites such as glassy carbon, nuclear graphite, pyrolytic graphite and natural graphite. An analysis based on the trapping model shows that positrons preferentially monitor structural defects such as the internal surfaces between crystallites and surfaces around pores or voids. The lifetime of free positrons delocalized in the perfect graphite lattice is estimated to be 215±10 ps. The lifetime of 400±20 ps, observed in well-crystallized pyrolytic graphite and natural graphite, is interpreted as the lifetime of positrons trapped at the internal surfaces between crystallites. It is possible to characterize different types of graphites by the positron lifetime data.
An Evaluation of Epitaxially Grown GaAs with Buffer Layer by Hall Measurements
Authors: Takahashi Kunihiko
Published: November 2005

Four kinds of mesa-type Hall measurement samples are fabricated from crystals obtained by liquid phase epitaxial growth of n-GaAs on semi-insulating GaAs substrates. A p-type buffer layer with a low carrier concentration is inserted between the active layer and the substrate in order to produce Hall measurement samples with high sensitivity and stability by mitigating effects from abnormal interfaces. The electron concentrations of the resulting Hall measurement samples have a spread of less than ±10%, so high mobility measurement samples can be fabricated. The variation of the Hall voltage with temperature is 10-5°C-1. The variation of the input resistance with temperature is 3×10-3°C-1. Finally, effects of stress to the measurement samples are described.
X-Ray Topography under Conditions of Monochromatic Spherical Wave Diffraction
Authors: Aristov V. V. , Ishikawa Tetsuya , Kikuta Seishi , Polovinkina V. I.
Published: November 2005

An X-ray topographic scheme was developed in which there is a large distance between the X-ray source and the specimen. A monochromatic X-ray beam with an angular divergence 6 ×10-5 rad obtained by double successive diffraction in the (n
1, +n
2) setting was used. This scheme enables diffraction focusing of a weakly absorbed wave field onto the exit surface of the crystal to be performed. Topographs of a wedge-shaped silicon crystal were obtained. Interference effects such as focusing, anomalous and ordinary Pendellösung effects peculiar to X-ray spherical wave diffraction were observed in the topographs with high resolution.
X-Ray Cl L2,3 Spectra and Electronic Structures of Transition-Metal Dichlorides
Authors: Nakamura Hatsuo , Ichikawa Kouichi
Published: November 2005

The valence-band structures of transition-metal dichlorides were studied using the X-ray spectroscopic technique. The Cl L2,3 emission band spectra of the valence band of Fe-, Co- and Ni-dichlorides were measured and compared with the valence-band XPS spectra and the Cl L2,3 absorption spectra. The peaks located around 192 and 196 eV in the Cl L2,3 emission band spectra are attributed to the p band and the d band which mainly originate from the Cl 3p state and the transition-metal 3d state, respectively. These spectra seem to reflect the energy-band structure and suggest that the unpaired 3d-electrons of transition-metal compounds scarcely affect the inner core 2p hole of Cl- ion.
Effect of Baking Temperature on Purity of LPE Ga0.47In0.53As
Authors: Amano Toshimasa , Takahei Ken-ichiro , Nagai Haruo
Published: November 2005

Liquid phase epitaxy (LPE) and the properties of high purity GaInAs layers on (100)InP substrates are reported. Low carrier concentration (3.8–5.4×1014 cm-3) and high electron mobility (47000–51000 cm2/V.s at 77 K) were obtained reproducibly. The influence of source Ga-In-As melt baking temperatures on the epitaxial layer purity was investigated. The results of a photoluminescence study and van der Pauw measurements show that acceptor impurities as well as donor impurities can be excluded from the source solution by a suitable heat treatment.
Short-Channel MOSFETs Fabricated Using CW Nd: YAG Laser Annealing of As-Implanted Source and Drain
Authors: Yoshida Masaaki , Okabayashi Hidekazu , Ishida Koichi
Published: November 2005

Short-channel MOSFETs have been fabricated using cw Nd: YAG laser annealing of As-implanted source and drain. The effective channel length measurement confirmed that the lateral spread of laser annealed source and drain regions was very small. The gain factor and the slope of subthreshold characteristics were much the same as those for furnace annealed devices. These results indicate that the SiO2/Si interface properties were not adversely affected by laser annealing.
On the Important Effect of Water Vapor in the Atmosphere on Void Formation in Quenched Pure Aluminum
Authors: Shimomura Yoshiharu , Kitagawa Kunihiko , Moritaki Yoshiziro
Published: November 2005

Zone-refined and nominally 99.999% pure aluminum foil specimens were rapidly quenched in hydrogen, helium and nitrogen. Two different heating methods, current heating and furnace heating, were employed. With the current heating, voids were observed in almost all quenched specimens, and with furnace heating, a large number of voids were observed only in the specimens heated in hydrogen and quenched. No voids were observed in specimens heated in helium or nitrogen and quenched into silicone oil. These results suggest that water vapor evaporated from distilled water or the chamber wall has great effect on the formation of voids. Without the effects of water vapor, the number density of voids in specimens quenched in hydrogen is proportional to the square root of the partial pressure of hydrogen. It is concluded that a small vacancy cluster which contains a hydrogen atom grows to a void.
Interactions between Electron Beam and Living Spores
Authors: Takahashi Ryoji
Published: November 2005

Detailed measurements of the increase in electron transmission through dying spores of Aspergillus niger provided action spectra for dehydration with electron energy peaks of 15 keV. According to this, Haskins' work on the killing effect of cathode rays on the same kind of spores, showing the maximum efficiency of killing at 3.5 keV, can be regarded as an action spectrum for destroying a particular substance in the spore. An explanation of the killing is as follows. White X-rays produced at the surface structure of the cell by impinging electrons with 3.5 keV energy, have an intensity maximum at about 2 keV, which corresponds to the absorption energy of phosphorus. H3PO4 molecules situated in the DNA chains absorb the X-ray energy and the chains are broken by releasing oxygen atoms. The dehydration of phosphoric acid by an electron beam was observed in order to check this model.
Coloring Properties of Cholesteric Liquid Crystals with Large Pitch
Authors: Hirata Shoji , Akahane Tadashi , Tako Toshiharu
Published: November 2005

Cholesteric liquid crystals with large pitch (P≥1 µm) have beautiful colors when they are between two polarizers. This coloring phenomenon is investigated theoretically and experimentally. The theoretical investigation is performed from a fundamental point of view without considering optical rotatory dispersion. In order to show the calculated result clearly, a method to show the distribution of the color in the cell thickness-pitch plane is proposed. The theoretical results agree well with the experimental results. It is shown that the conventional treatment which takes into account optical rotatory dispersion is not good an approximation for a CLC with large pitch.