bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of a cDNA library from the turkey (Meleagris gallopavo)
Authors: Chaves L D , Rowe J A , Reed K M
Published: February 2005

Genome characterization and analysis is an imperative step in identifying and selectively breeding for improved traits of agriculturally important species. Expressed sequence tags (ESTs) represent a transcribed portion of the genome and are an effective way to identify genes within a species. Downstream applications of EST projects include DNA microarray construction and interspecies comparisons. In this study, 694 ESTs were sequenced and analyzed from a library derived from a 24-day-old turkey embryo. The 437 unique sequences identified were divided into 76 assembled contigs and 361 singletons. The majority of significant comparative matches occurred between the turkey sequences and sequences reported from the chicken. Whole genome sequence from the chicken was used to identify potential exon–intron boundaries for selected turkey clones and intron-amplifying primers were developed for sequence analysis and single nucleotide polymorphism (SNP) discovery. Identified SNPs were genotyped for linkage analysis on two turkey reference populations. This study significantly increases the number of EST sequences available for the turkey.Key words: turkey, cDNA, expressed sequence tag, single nucleotide polymorphism.
Taxonomic relationships amongArachissect.Arachisspecies as revealed by AFLP markers
Authors: Milla S R , Isleib T G , Stalker H T
Published: February 2005

Cultivated peanut, Arachis hypogaea L., is a tetraploid (2n = 4x = 40) species thought to be of allopolyploid origin. Its closest relatives are the diploid (2n = 2x = 20) annual and perennial species included with it in Arachis sect. Arachis. Species in section Arachis represent an important source of novel alleles for improvement of cultivated peanut. A better understanding of the level of speciation and taxonomic relationships between taxa within section Arachis is a prerequisite to the effective use of this secondary gene pool in peanut breeding programs. The AFLP technique was used to determine intra- and interspecific relationships among and within 108 accessions of 26 species of this section. A total of 1328 fragments were generated with 8 primer combinations. From those, 239 bands ranging in size from 65 to 760 bp were scored as binary data. Genetic distances among accessions ranged from 0 to 0.50. Average distances among diploid species (0.30) were much higher than that detected between tetraploid species (0.05). Cluster analysis using different methods and principal component analysis were performed. The resulting grouping of accessions and species supports previous taxonomic classifications and genome designations. Based on genetic distances and cluster analysis, A-genome accessions KG 30029 (Arachis helodes) and KSSc 36009 (Arachis simpsonii) and B-genome accession KGBSPSc 30076 (A. ipaensis) were the most closely related to both Arachis hypogaea and Arachis monticola. This finding suggests their involvement in the evolution of the tetraploid peanut species.Key words: peanut, numerical taxonomy, genome donors, classification.
Distribution of MWG699 polymorphism in Spanish European barleys
Authors: Casas A M , Yahiaoui S , Ciudad F , Igartua E
Published: February 2005

The STS marker MWG699/TaqI is closely linked to the vrs1 locus and has been proposed as a marker of domestication in barley. This study included 257 cultivated barleys of both two- and six-rowed varieties, mainly from the western Mediterranean region. These included many landraces from the Spanish barley core collection, Moroccan landraces, and a set of accessions from other European countries. Restriction analysis of amplified DNA revealed three alleles, as previously described. Most of the two-rowed entries had the same allele, type K. Six-rowed entries showed both types A and D. Indeed, type D was widespread among Spanish landraces and commercial varieties from central Europe. It was also found in some two-rowed landraces originating from Spain and Morocco. Barleys with the D haplotype were predominantly winter types, whereas the A haplotype was evenly distributed among spring and winter types. These results support the existence of two different genetic sources among six-rowed Spanish landraces.Key words: barley, origin, SBCC, Spanish barley core collection, haplotype.
Induction of wheat defense and stress-related genes in response toFusarium graminearum
Authors: Kong Lingrang , Anderson Joseph M , Ohm Herbert W
Published: February 2005

Fusarium head blight (FHB), caused by species of the fungus Fusarium, is a worldwide disease of wheat (Triticum aestivum L.). The Chinese T. aestivum 'Ning7840' is one of few wheat cultivars with resistance to FHB. To identify differentially expressed genes corresponding to FHB resistance, a cDNA library was constructed using pooled mRNA isolated from glumes of 'Ning7840' harvested at 2, 6, 12, 24, 36, 72, and 96 h after inoculation (hai) with a conidia spore suspension of Fusarium graminearum. Suppressive subtractive hybridization (SSH) cDNA subtraction was carried out using pooled glume mRNAs from the tester and the control. The cDNA library was differentially screened using the forward subtracted cDNAs and the reverse subtracted cDNAs as probes. Twenty-four clones with significant matches to either plant (16 sequences) or fungal (8 sequences) genes were isolated based on their specific hybridization with forward subtracted cDNA and not reverse subtracted cDNA. Six putative defense-related genes were confirmed by real-time quantitative reverse-transcriptase PCR. Many-fold higher induction of three clones (A3F8, B10H1, and B11H3) in the resistant genotypes compared with susceptible genotypes indicates a putative role in the resistance response to Fusarium graminearum. Transcript accumulations of P450, chitinase (Chi1), and one unknown gene (clone B8Q9) in both resistant and susceptible genotypes suggest an involvement in a generalized resistance response to F. graminearum. Nucleotide sequence analysis showed that cDNA clone A4C6 encodes a cytochrome P450 gene (CYP709C3v2), including 14 N-terminal amino acids that have a membrane-associated helical motif. Other domains characteristic of eukaryotic P450 are also present in CYP709C3v2. The deduced polypeptide of cDNA clone B2H2 encodes an acidic isoform of class I chitinase containing a 960-bp coding region. Southern hybridization using aneuploid lines of T. aestivum 'Chinese Spring' indicated that CYP709C3v2 was located on the short arm of chromosomes 2B and 2D.Key words: Fusarium head blight (FHB), suppressive subtractive hybridization, defense response, real-time quantitative RT-PCR.
Genome relationships in polyploidPoa pratensisand otherPoaspecies inferred from phylogenetic analysis of nuclear and chloroplast DNA sequences
Authors: Patterson Jason T , Larson Steven R , Johnson Paul G
Published: February 2005

The genus Poa comprises approximately 500 species that occur throughout the world, including the widely grown Kentucky bluegrass (P. pratensis L.). Hybridization and polyploidization have played a prominent role in the evolution of this complex genus, but limited information is available regarding genome relationships in Poa. Thus, we amplified, cloned, and compared the DNA sequences of 2 nuclear genes (CDO504 and thioredoxin-like protein) and 2 chloroplast genome loci (ndhF and trnT–trnF) from 22 Poa species. Four distinct classes of sequences corresponding to 4 putative homoeologous loci from each nuclear gene were found within polyploid P. pratensis. Nuclear sequences from 15 other Poa species were found to group with at least 1 P. pratensis homoeolog, whereas 6 species displayed sequences not present in P. pratensis. The nuclear genome phylogenies presented here show the first evidence of diverse and related genomes in the genus Poa.Key words: phylogeny, polyploidy, chloroplast genome, nuclear genome, Kentucky bluegrass.
Genomic analysis of a region encompassingQRfs1andQRfs2: genes that underlie soybean resistance to sudden death syndrome
Authors: Triwitayakorn K , Njiti V N , Iqbal M J , Yaegashi S , Town C , Lightfoot D A
Published: February 2005

Candidate genes were identified for two loci, QRfs2 providing resistance to the leaf scorch called soybean (Glycine max (L.) Merr.) sudden death syndrome (SDS) and QRfs1 providing resistance to root infection by the causal pathogen Fusarium solani f.sp. glycines. The 7.5 ± 0.5 cM region of chromosome 18 (linkage group G) was shown to encompass a cluster of resistance loci using recombination events from 4 near-isogenic line populations and 9 DNA markers. The DNA markers anchored 9 physical map contigs (7 are shown on the soybean Gbrowse, 2 are unpublished), 45 BAC end sequences (41 in Gbrowse), and contiguous DNA sequences of 315, 127, and 110 kbp. Gene density was high at 1 gene per 7 kbp only around the already sequenced regions. Three to 4 gene-rich islands were inferred to be distributed across the entire 7.5 cM or 3.5 Mbp showing that genes are clustered in the soybean genome. Candidate resistance genes were identified and a molecular basis for interactions among the disease resistance genes in the cluster inferred.Key words: QTL, Gbrowse, fine map, resistance, soybean SDS, Fusaria.
A Thin-Film Transistor Using a Reactive-Ion-Beam-Deposited Polycrystalline Silicon Film
Authors: Nakazawa Kenji , Yamada Hiroshi , Kohda Shigeto , Torii Yasuhiro
Published: February 2005

A thin-film transistor (TFT) has been fabricated at a maximum temperature of 600degC using a reactive ion-beam-deposited polycrystalline silicon (polysilicon) film. To improve TFT characteristics, the deposition conditions of polysilicon film have been investigated. It is found that polysilicon film crystallinity can be improved by controlling the energy of ionized species. X-ray diffraction spectra and reflective high-energy electron diffraction (RHEED) patterns indicate that (110)-preferred orientation dominates in the film. The deviation of the (110) textured axis becomes very small as ion energy increases. The field effect mobility of TFTs increases as ion energy increases.
Dielectric Properties of Plasma-Polymerized Tetrafluoroethylene Films
Authors: Nakano Toshiki , Fukuyama Masao , Ohki Yoshimichi
Published: February 2005

A plasma-polymerized tetrafluoroethylene film has dielectric loss peaks below -50degC and approximately at 40degC. The effects of the substrate temperature during polymerization and of plasma irradiation after polymerization on the appearance of the peaks were studied. The low-temperature peak seems to be due to local-mode relaxation of polar groups, while the high-temperature peak seems to be due to phase transition.
Negative Resistance in AlxGa1-xAs:Si Red Light-Emitting Diodes
Authors: Park Seounghwan , Jang Seongjoo , Choe Byungdoo
Published: February 2005

A negative resistance is directly observed near 77 K in Si-doped Al
x
Ga1-x
As diodes with a P-P°-N structure. A strong emission at the P°-P boundary originating from the recombination barrier is also directly observed. The negative resistance can be explained by the trap-filling mechanism.
Physical Properties of Ferroelectric Liquid Crystals and AC Field-Stabilization Effect
Authors: Nagata Tetsuya , Umeda Takao , Igawa Tatsuo , Mukoh Akio , Hori Yasuro
Published: February 2005

The relation between physical properties of ferroelectric liquid crystals (FLCs) and the AC field stabilization effect is described. The AC field-stabilization effect depends on a dielectric anisotropy Δε and a tilt angle θ. We introduced the parameter α defined by α=-Δε·sin
2θ and experimentally clarified that the FLCs with a large value of the parameter α showed a large AC field-stabilization effect. This is confirmed by using a FLC mixture with a large value of α so that the alignment state reset by a DC electric field is completely maintained for a certain time by superposing a high-frequency AC electric field to the DC electric field, even if the polarity of the DC electric field changes.
Determination of Space Group and Refinement of Structure Parameters for La2CuO4-δ Crystals
Authors: Yamada Kazuyoshi , Kudo Eisuke , Endoh Yasuo , Tsuda Kenji , Tanaka Michiyoshi , Kokusho Koichi , Asano Hajime , Izumi Fujio , Oda Migaku , Hidaka Yoshikazu , Suzuki Minoru , Murakami Toshiaki
Published: February 2005

The space group in the orthorhombic phase of La2CuO4-δ was confirmed to be Cmca for both as grown and deoxygenated crystals by using conventional and convergent beam electron diffraction together with high resolution neutron powder diffraction methods. The Rietveld refinements of neutron powder diffraction data determined the structural parameters. Slight differences in lattice constants, positional parameters and occupation factor for oxygen atoms were found between the two crystals.
Growth of In0.5Ga0.5P on GaAs by LPE: The influence of Growth Temperature and Lattice Mismatch on Photoluminescence
Authors: Chang L. B. , Cheng K. Y. , Liu C. C.
Published: February 2005

InGaP epilayers were grown on (100) GaAs substrate by liquid phase epitaxy (LPE). Four different growth temperatures, 800, 750, 710 and 700degC were studied. We found that the lattice match condition for growth-homogeneous epitaxial layers relaxed at 800degC, and shrank with decreasing growth temperatures. As to the 700degC growth temperature, the growth melts were difficult to wipe off the substrate and no homogeneous epilayers could be obtained. The photoluminescence (PL) intensity of the growth layers depended on both the lattice match condition and the growth temperature. The defect-related PL peaks, at 39 and 37 meV below the band edge, were observed in most of the layers grown at 800 and 750degC, respectively. In a layer grown at 710degC, the defect-related subpeak became broad and dominated the PL spectrum. With a growth temperature of 750degC and a lattice mismatch (Δa
⊥/a
s) of 0.2%, the InGaP epitaxial layers showed a mirror-like surface morphology, the strongest PL intensity, the narrowest PL FWHM (6 meV at 17 K) and a minimal defect-related PL subpeak.
Planar Faults and Grain Boundary Precipitation in Non-Stoichiometric (Sr, Ca)TiO3 Ceramics
Authors: Fujimoto Masayuki , Tanaka Junzo , Shirasaki Shinichi
Published: February 2005

Microstructures of non-stoichiometric-composition (Sr0.85Ca0.15O)
x
TiO2 ceramics (with x=0.98 and 1.02) were observed using high-resolution transmission electron microscopy and scanning transmission electron microscopy. Precipitation of Magnéli-phase was found at the grain boundary in the specimen for x=0.98, and Ruddlesden-Popper-type insertion layers in that for x=1.02. The crystallographic site occupancy of impurity atoms determined by ALCHEMI (Atom Location using CHanneling-Enhanced MIcroanalysis), showed that the excess TiO2 was precipitated as Magnéli phase in the specimen for x=0.98, and similarly that excess SrO formed insertion planar faults of NaCl type in that for x=1.02. No anti-site point defects were formed in either of the specimens.
Metastable Phase Formation by Ion Beam Mixing for the Al–Mn System
Authors: Kido Yoshiaki , Noritake Tatsuo , Kawamoto Jun-ichi
Published: February 2005

The metastable τ phase of Al–Mn with ferromagnetism is formed directly by ion beam induced mixing with 400 keV Xe+, 290 keV Kr+ and 150 keV Ar+ ions. The magnetic properties strongly depend on the ion dose, ion species, thickness ratio of Al to Mn layer and substrate temperature during ion irradiation. The maximum value of the saturation magnetization σ achieved is 36 emu / g, which corresponds to about 40 at% of the alloyed layer estimated from the bulk σ value. The grain size of the metastable τ phase is observed to be 10–40 nm by transmission electron microscopy (TEM). The present work has clarified the kinetics of ion beam mixing and the growth mechanism of the metastable phase. It is concluded that collision cascades connected dynamically with the radiation-enhanced diffusion play a decisive role in forming directly the metastable τ phase.
Deposition of Hydrogenated Microcrystalline Films of CdTe by Chemical Sputtering in Hydrogen
Authors: Saito Koji , Nishibayashi Yoshiki , Imura Takeshi , Osaka Yukio
Published: February 2005

Films of CdTe are deposited by chemical sputtering of a CdTe target in hydrogen gas. X-ray diffraction patterns show that the films are composed of microcrystals of cubic CdTe with a grain size of 15∼30 nm. The films contain a trace amount of hydrogen in the form of the Cd–H (and presumably Te–H2) bonds. This hydrogen is evolved during the thermal treatment of the film above 100degC, as the grain size of the microcrystal grows. The deposition rate is also reduced when the substrate temperature increases up to 100degC or more.
Secondary Electron Emission Characteristics of Heavy-Metal Oxide Coatings for CRT Shadow Mask
Authors: Koitabashi Masayasu , Yamamoto Morio , Kimura Hiroshi , Hattori Atsushi , Watanabe Tetsuya , Nakano Tomoki
Published: February 2005

In order to reduce the misalignment caused by the thermal expansion of the shadow mask originated from the deposition of the primary electron energy, the secondary electron emission (SEE) characteristics of Bi2O3 and Fe3O4 coatings for the CRT shadow mask are studied. The total SEE yield of the Bi2O3 coating varies from 0.96 at a primary electron energy of 15 keV to 0.75 at 30 keV. These values are about twice as high as those of the Fe3O4 coating. The backscattered electron yield of the Bi2O3 coating increases almost linearly from 0.36 at a primary electron energy of 15 keV to 0.40 at 30 keV. That of the Fe3O4 coating also increases in the same manner, although its magnitude is much smaller. These measured values agree with the estimated values from the reported data which give the SEE yield as a function of the atomic number. The average energy of the backscattered electrons can be also estimated to be about 24% of the incident primary energy for the Bi2O3 coating, and 12% for the Fe3O4 coating. These results shows that the Bi2O3 coating effectively reduces the deposition of primary electron energy onto the shadow mask by the backscattering of incident primary electrons. Therefore, the Bi2O3 coating will result in the reduction of the temperature rise and the thermal expansion of the shadow mask to a greater extent than the Fe3O4 coating.
Axial Intensities of Focused Truncated Elliptical Gaussian Beams
Authors: Horng Jing Shyang
Published: February 2005

Axial intensities have been calculated for an elliptical Gaussian beam, like that produced by a semiconductor laser. The beam is focused by a thin lens, which fills a circular aperture of any prescribed radius. It was found that there are two intensity maxima along the axis in the system of the Fresnel number N≫1. These two maxima merge into one as the Fresnel number decreases, and as a consequence, the intensity fluctuation along the axis is reduced. Further evolution is concerned with the oscillations and rapid transition of the point of the absolute maximum intensity in the course that leads to an approach of this point toward the focusing lens.
Production of ECR Mirror Plasma by High Power Millimeter-Wave Radiation
Authors: Arata Yoshiaki , Miyake Shoji , Kishimoto Hiroaki , Abe Nobuyuki , Kawai Yoshinobu
Published: February 2005

Using a high power 60 GHz gyrotron, a high density electron cyclotron resonance (ECR) plasma production is studied in a simple mirror field in Ar gas, over the wide range of the gas pressures between 4×10-3 Pa and 2×10-1 Pa. Time variation of the electron density is studied in detail. In the quasi-steady state it reveals a fully ionized state with an electron density in the range of 1012 cm-3 at most, which is lower than the cut-off density of the incident wave whether the wave launch is performed in the radial or axial direction. Discussion of the usefulness of this plasma as a multiply-charged ion and UV-VUV radiation source is also given.
Calibration of Minority Carrier Lifetimes Measured with an ac Photovoltaic Method
Authors: Honma Noriaki , Munakata Chusuke , Shimizu Hirofumi
Published: February 2005

Calibration curves for estimating true lifetimes from the measured ones are theoretically obtained for getting the long lifetimes of relatively thin Si wafers, where lifetimes measured with an ac photovoltaic method are limited by the sample thickness. Apparent lifetimes of 7.2 through 14 µs in 475 µm thick p-type Si wafers are calibrated to be 9.6 through 65µs, respectively, using the calibration curves. As a result, it is found that lifetimes in the samples oxidized after dipping in HF solution are longer than those oxidized without dipping in HF solution. This is because contaminated natural oxide films on the sample, which are formed by alkaline rinse, are eliminated by the HF dipping.
A System for Long-Pulse REB Generation
Authors: Tsuzuki Tetsuya , Hasegawa Mitsuru , Narihara Kazumichi , Tomita Yukihiro , Kubo Shin , Kobata Tadasuke , Mohri Akihiro
Published: February 2005

A high-voltage pulse generator system producing intense relativistic electron beams (REB)(1.5 µs pulse width, 30 kA peak current, 1 MeV energy) was developed for the use of REB ring formation. This system consists of a Marx generator, 7-m-long transmission lines with plastics-water hybrid insulators and a magnetically insulated transmission line connected with a cathode. Plastics of the hybrid insulators mainly withstand electric breakdown, whereas local electric field concentration is degraded by water having a high permittivity. A high vacuum in the REB formation vessel is realized by the use of an interface of ultrahigh-molecular polyethylene between the line and the vessel. The system has been operated more than twenty thousand shots without encountering a breakdown.
Optical Absorption Spectra in CuInS2 Doped with Fe, Mn and Cr
Authors: Sato Katsuaki , Isawa Mikio , Takahashi Nobumitsu , Tsunoda Hiroshi
Published: February 2005

Optical absorption spectra were measured in single crystals of CuInS2 doped with Fe, Mn and Cr grown by the chemical transport technique. Intense absorption bands characteristic of individual transition elements were observed. Absorption bands introduced by Fe and Mn were attributed to the photoionization transition, while those by Cr were assigned to the ligand-field transition.
The Formation of Silica W with Oxidation of Vapor Silicon Monoxide
Authors: Kajiwara Meisetsu
Published: February 2005

The formation of silica W was investigated with oxidation of vapor silicon monoxide prepared by the reduction of silica by silicon or disproportionation of silicon monoxide. A small amount of silica W was prepared with disproportionation of silicon monoxide. In the case of the reduction of silica with silicon, the formation of silica W needed a degree of 10-3 atm over vacuum conditions. The silica W prepared was measured by EPMA, and the results obtained showed that nitrogen was included in silica W.
ESR of AgNO3
Authors: Tagaya Kimihito
Published: February 2005

A broad ESR absorption was observed for a single crystal of AgNO3 at room temperature. The absorption intensity increased suddenly with decreasing temperature from 120 K, and became maximum at 81 K. Then, the g-value approached 2.0. The absorption intensity at 81 K was about twenty times as strong as that at room temperature. The spin number was nearly equal to the molecule number of AgNO3 at 81 K. A possible interpretation for the results is discussed in terms of an electron transfer from the NO3
- ion to the Ag+ ion.
Reincrease in Electron Density in the Current-Decaying Phase of Pulsed-Discharge of Argon-Hydrogen Mixture
Authors: Watanabe Yukio , Shiratani Masaharu , Ogi Sukeomi , Kunihiro Naoki , Ogawa Isao
Published: February 2005

A noticeable reincrease in electron density was observed during the current-decaying phase of a pulsed Ar+H2(10%) discharge in a pressure range of 133∼800 Pa. It was experimentally verified by using laser-induced fluorescence and self-absorption methods that the reincrease appeared concurrently with the increase in a population density of the first excited state of H atoms. This phenomenon can be reasonably explained by a mechanism that such excited atoms increase due to dissociative recombination of ArH+ions generated in the ionizing phase of the discharge and they are reionized by electron collisions. A proposed model, which was expressed both by rate equations of H atoms on the ground and excited states and three kinds of ions such as H+, H3+and ArH+and by a quasi-neutral equation of the plasma, can qualitatively explain these experimental results.
A KrF Excimer Laser Lithography for Half Micron Devices
Authors: Ogawa Kazufumi , Sasago Masaru , Endo Masayuki , Ishihara Takeshi
Published: February 2005

An excimer laser stepper has been developed for use in 0.5 µm pattern fabrication. The excimer laser stepper is characterized using a 5× monochromatic quartz lens (exposure area: 10×10 mm2) and a new KrF excimer laser whose oscillation spectrum is limited to a narrow band (FWHM=0.008 nm) by using an etalon. A speckle-free pattern exposure with half-micron order was possible using this apparatus. A resolution of 0.4 µm line and space pattern was obtained by single-layer resist process using a commercial deep UV resist, although its pattern profile was poor. A high-aspect ratio of 0.5 µm line and space pattern was obtained by a trilayer resist process. With this apparatus, a high throughput equivalent to that of a conventional g-line stepper can be expected.
Submicron-Scale Tip Fabrication for Magnetic Force Microscopy by Electrolytic Polishing
Authors: Iijima Tetsuo , Yasuda Kyosuke
Published: February 2005

An electrolytic polishing technique which exposes a portion of an insulated wire and etches that portion preferentially is described. The prepared tip's configuration immediately prior to dropping off depends on the tip's weight and mechanical properties. The tip-point curvature can be below-submicron scale. Magnetic force imaging of recorded magnetic tape using these tips is shown.
Saturation and Detuning Effects of Pump Waves in VUV Generation by Resonant Sum Frequency Mixing in Hg
Authors: Tsukiyama Koichi , Tsukakoshi Motowo , Kasuya Takahiro
Published: February 2005

Saturation and detuning effects on VUV generation are observed in resonance sum frequency mixing in Hg. The results demonstrate that the mechanism of VUV generation is different above and below 9p1P1 at 79964.1 cm-1 and that higher order effects in the pump and probe powers should be taken into account.
Low Temperature Characteristics of GaAs FET (3SK97, 3SK121) for UHF SQUID
Authors: Takeda Takashi , Haeiwa Tetsuzi , Kita Eiji , Tasaki Akira
Published: February 2005

The low temperature characteristics of GaAs FET (3SK97, 3SK121) were examined with respect to the usage of a GaAs FET for a preamplifier of a UHF SQUID. A diode connection of the FET was also attempted in which it was utilized as a varactor diode operating at 4.2K. A preamplifier for the UHF SQUID was successfully constructed using these FETs.
Microscopic Mechanism for the Photo-Creation of Dangling Bonds in a-Si:H
Authors: Morigaki Kazuo
Published: February 2005

We present a microscopic model for the photocreation of silicon dangling bonds, taking into account the combined effects of breaking of weak bonds, Si–H bond switching, and H-tunneling which occur under intense optical excitation. We also discuss the kinetics of the photocreation of silicon dangling bonds, taking into account that the other defects than dangling bonds are photocreated.
Effect of Ar Gas Pressure on Structure and Magnetic Properties of Sputter-Deposited Fe-Ag Alloys
Authors: Sumiyama Kenji , Kataoka Noriyuki , Nakamura Yoji
Published: February 2005

Fe1-x
Ag
x
alloy films have been sputter-deposited on water-cooled substrates under Ar gas pressures, P
Ar, of 8.9 and 0.23 Pa (67 and 1.7 mTorr). X-ray diffraction, scanning electron micrography (SEM), the Mössbauer effect and magnetization measurements were made on these films. In contrast to the immiscibility of Fe and Ag even at 2300 K, the single bcc and fcc phases are obtained in these sputter-deposited alloys. The single bcc phase region is extended and the single fcc phase fcc phase region is reduced with increasing P
Ar. The alloy films deposited under a high P
Ar have a columnar structure in the SEM image and show a perpendicular magnetic anisotropy in the Mössbauer spectrum, while those under a low P
Ar have a fibrous structure in the SEM image and show an in-plane magnetic anisotropy in the Mössbauer spectrum.
The Origin of Residual Carriers in CVD-Grown 3C-SiC
Authors: Okumura Hajime , Shinohara Mikiya , Kuroda Shin-ichi , Endo Kazuhiro , Sakuma Eiichiro , Misawa Shunji , Yoshida Sadafumi
Published: February 2005

PL and ESR spectra were measured for unintentionally doped and N-doped 3C-SiC epilayers grown on Si by CVD in order to clarify the origin of residual carriers in the SiC films. PL spectra of lightly N-doped samples show broad peaks in addition to the sharp peaks observed for unintentionally doped ones. The intensities of these broad peaks increase with the N2 partial pressure during growth. ESR signals of the 3C-SiC films consist of a sharp triplet and a broad structure. The spin densities of the unintentionally doped samples at 4.2 K are estimated to be much lower than the carrier densities at room temperature. From these experimental results, we can conclude that the main origin of the residual carriers in unintentionally doped 3C-SiC is not attributed to simple nitrogen donors.
Non-Alloyed Ohmic Contacts to n-GaAs Using Compositionally Graded InxGa1-xAs Layers
Authors: Nittono Takumi , Ito Hiroshi , Nakajima Osaake , Ishibashi Tadao
Published: February 2005

Non-alloyed ohmic contacts to n-GaAs using compositionally graded In
x
Ga1-x
As layers grown by molecular beam epitaxy are studied. The carrier concentration reduction in the GaAs buffer layer due to low growth temperature is found to increase overall contact resistance for an n+-InAs/In
x
Ga1-x
As(x=1→0)/GaAs structure. The lowest specific contact resistance (ρ
c
) ever reported, 5×10-9 Ω · cm2, is obtained with a 2×1019 cm-3 Si-doped structure grown at 450°C. A similar ρ
c
value is also obtained when the InAs mole fraction is higher than 0.7. Using WSi as a contact metal, a refractory ohmic contact is realized in which ρ
c
remains less than 2×10-7 Ω · cm2 under annealing up to 800°C.
Tomographic Approach Using an Electrostatic Analyzer for the Measurement of the Three-Dimensional Ion Velocity Distribution of Plasma
Authors: Iwama Naofumi , Lehner Thierry , Noziri Hisayoshi , Okado Masataka
Published: February 2005

The measurement of the ion velocity distribution in full three-dimensional velocity space is studied with a planar retarding-grid rotating analyzer immersed in plasma. In spite of the plane geometry of the analyzer, the current-voltage measurement in different directions can provide useful information for the three-dimensional measurement with the aid of numerical techniques of computerized tomography. The practical usefulness of this method as a diagnostic tool is shown experimentally for a weakly ionized collisionless argon plasma into which a low-energy ion beam is injected uniformly. Discussions are made with emphasis on the optimization of measurement by compromising the contradiction between the spatial resolution and the statistical accuracy.
Numerical Analysis of Error Fields due to Port Holes in a Plasma Confinement Device
Authors: Saito Kazuyoshi , Yoshida Zensho , Inoue Nobuyuki , Uesaka Mitsuru , Hoshi Yuichi
Published: February 2005

Eddy currents induced in vacuum and structural components of plasma confinement devices generate irregular magnetic fields. One of the most serious problems for plasma confinement in reversed-field-pinch (RFP) is such error fields. In this paper, error fields produced by current in a vacuum vessel with port holes are calculated using an eddy current analysis code for a three-dimensional thin shell structure, INCANET, and the effect of bridging the port holes with conductive plates to reduce the error fields is estimated. These numerical analyses have been done for the REPUTE-1 RFP
Topographical Contrast of Secondary Electron Intensity Profiles in Focused Ion Beam Implantation
Authors: Morita Tetsuo , Hashimoto Hisao
Published: February 2005

A new calculation method of secondary electron intensity profiles in the case of scanning the focused ion beam across an alignment mark is proposed. The secondary electron intensity profiles depend on the energy of the incident ion, surface conditions of the target material and topography of the substrate, etc. Secondary electron intensity profiles can be easily calculated for variation of geometrical parameters without Monte Carlo calculation. The collection efficiency of secondary electrons is also included in this calculation. The calculated results agree with the measured ones.
Electron Microscopic Observation of Heterointerface in GaxIn1-xAsyP1-y/InP Grown by Liquid
Authors: Kuwano Noriyuki , Goto Tomoyuki , Oki Kensuke , Uchiyama Seiji , Iga Kenichi
Published: February 2005

Cross-sectional observation of the heterointerfaces of a Ga
x
In1-x
As
y
P1-y
active layer clad in InP in a laser diode wafer with x=0.3 and y=0.6 was carried out using an electron microscope. By comparing the image contrasts obtained by high resolution observation and weak beam observation, it is rerealed that if the heterointerface is smooth, high resolution observation can show the interface structure, but a weak beam method is still useful to characterize a heterointerface of relatively large unevenness.
Propagation of Vertical Bloch Line Pairs around Stripe Head by Single Phase Current
Authors: Fukunaga Hirotoshi , Sadatomi Kunihiro
Published: February 2005

This note reports on a new method to propagate vertical Bloch line (VBL) pairs, which are the information units in the recently proposed VBL memory, around stripe heads by single phase current. The method reported has simpler conductor patterns than the method to propagate by two circuit currents. The bias field margin for the propagation has been obtained by computer simulation and the reliability of the method has been confirmed.
Changes of DLTS Spectrum with Gold Concentration and Gold-Diffusion Temperature in N-Type Silicon
Authors: Morooka Masami , Tomokage Hajime , Yoshida Masayuki
Published: February 2005

Gold was in-diffused into n-type silicon single crystals at 800-1150°C. DLTS spectra of the Schottky diode of the specimen were measured and four peaks (E
c-0.16, E
c-0.24, E
c-0.30 and E
c-0.54 eV) were observed. As the gold concentration and the gold-diffusion temperature increased, the relative height of the peak of E
c-0.24 eV increased compared to the most prominent peak of E
c-0.54 eV. The concentration of the peak of E
c-0.30 eV was saturated at about (1-4)×1014 cm-3.
Breakdown Characteristics of SF6-N2 Mixture in High Nonuniform Field Gap under Pulse Voltage
Authors: Nakayama Hiroshi , Onoda Mitsuyoshi , Kuroda Shigeji , Amakawa Kiyoshi
Published: February 2005

The corona and breakdown characteristics of gas mixtures were investigated in a positive needle gap, using µs pulse voltage with various rise times. The breakdown voltage reached a maximum value as the rise time increased, and reduced at longer rise times. An extremely high breakdown voltage was obtained with the addition of a very small percentage of SF6 to N2.
Electronic Interaction between Metal Additives and Tin Dioxide in Tin Dioxide-Based Gas Sensors
Authors: Matsushima Shigenori , Teraoka Yasutake , Miura Norio , Yamazoe Noboru
Published: February 2005

The electronic interaction of SnO2 with Ag and Pd particles dispersed on its surface was examined by means of X-ray photoelectron spectroscopy (XPS). The binding energies (BE) of Sn3d and O1s of Ag(1.5 wt%)-SnO2 and Pd(3.0 wt%)-SnO2, which were lower by 0.5–0.7 eV than those of pure SnO2 in the as-prepared state, shifted reversibly by reduction and oxidation treatments. These shifts in BE are shown to reflect the shifts of Fermi energy of SnO2 which are interacting electronically with the metal additives. The electronic interaction depended on the metal loading, being strongest at 1.5 wt% and 3.0 wt% loadings of Ag and Pb, respectively. The implication is that the electronic interaction is of primary importance to the inflammable gas detection by Ag-SnO2 sensors.
Electronic Properties and Modeling of Lattice-Mismatched and Regrown GaAs Interfaces Prepared by Metalorganic Vapor Phase Epitaxy
Authors: Ikeda Eiji , Hasegawa Hideki , Ohtsuka Shunsuke , Ohno Hideo
Published: February 2005

In order to study and model non-ideal semiconductor-semiconductor interfaces, three kinds of GaAs interfaces, i.e., (i) a slightly mismatched InGaAs / GaAs interface, (ii) a highly mismatched GaAs / InP interface and (iii) an air-exposed GaAs / GaAs interface, were prepared by MOVPE. Their electronic properties were studied through measurements of C-V characteristics, carrier concentration profiles, DLTS spectra and I-V characteristics. By a novel interpretation of C-V characteristics and DLTS spectra, all the experimental results were explained consistently by a common model involving a U-shaped interface state continuum. The origin of the interface state continuum is explained by the disorder induced gap state (DIGS) model recently proposed for insulator-semiconductor and metal-semiconductor interfaces. This model seems to serve as a universal model for non-ideal S-S interfaces.
Dissipative Tunneling in Dielectric Films
Authors: Asadullayev N.A. , Ciric I.
Published: February 2005

A new phenomenon of the dissipative tunneling in insulator films has been found. This means that the conductivity of thin amorphous films of silicon nitride stimulated by a strong electric field in a magnetic field at low temperatures could be increased by increasing the electric field intensity. The magnetoresistance effect is positive in a relatively low electric field and becomes negative in a higher electric field. This effect is due to the charge carriers scattering on impurities under the barrier during tunneling in an external magnetic field and is strongly dependent on the electric field intensity.
Electrical, Magnetic and Superconducting Properties of the High-Tc Superconductor Ba2Nd1-xPrxO7-δ
Authors: Koyama Kuniyuki , Suzuki Yasuji , Noguchi Seiichiro
Published: February 2005

Structure, resistivity and susceptibility have been studied in the Ba2Nd1-x
Pr
x
Cu3O7-δ system. The samples with 0≤x≤1 have a single phase of the orthorhombic Ba2YCu3O7-δ structure. The T
c decreases linearly with increasing x and superconductivity is not observed for the samples of x≥0.3. The valences of Nd and Pr ions in the samples were determined from the susceptibility measurement as Nd3+ and Pr4+, respectively. It is supposed naturally that the valence of Cu2 ions (Cu ions in the two-dimensional Cu–O plane) is affected strongly by the neighboring rare earth ions. The results show that the valence of Cu2 ions is significant for the superconductivity in the Ba2RECu3O7-δ system.
Effects of Ultrasonic Bonding Materials on Velocity and Attenuation of Sound in Red Lauan Wood
Authors: Kamioka Hiroaki
Published: February 2005

The effects of ultrasonic bonding materials between an acoustic transducer and a specimen surface on the velocity and attenuation of sound in red lauan wood were studied by using the ultrasonic pulse transmission method, since it was important to determine the acoustic coupling between the transducer and the specimen for measuring the sound velocity and attenuation in highly dissipative materials such as wood.
Vaseline, grease, various kinds of machine oils, etc., were employed as an ultrasonic bonding material. The energy dissipation of sound was smallest in the case of grease. By combining the data of attenuation with that of the sound velocity, the effects of ultrasonic bonding materials on the ultrasonic behavior in red lauan wood are reported and discussed.
Interaction between Particles and a Wave in a System of Magnetic-Trapping Acceleration by an Electromagnetic Wave
Authors: Kawata Shigeo , Manabe Atsushi , Yabe Takashi , Takeuchi Satoshi , Sakai Kazuo , Sugihara Ryo
Published: February 2005

The wave-particle interaction is investigated for V

p
×B acceleration or magnetic-trapping acceleration by an electromagnetic wave. We present a condition for efficient particle acceleration: the trapped particles are accelerated efficiently if the number density of the imposed particles and the time interval for the acceleration are appropriate. When the condition is violated, severe modification of the electric field of the wave takes place and the efficient particle acceleration cannot be accomplished.
Growth and Optical Properties of Li13Nd(GeO4)4 Single Crystal
Authors: Maeda Masaki , Seino Hiroaki , Kadoi Mikio , Ikeda Takuro
Published: February 2005

In this paper, single crystals of Li13Nd(GeO4)4 are grown by the Czochralski method. The unit cell dimensions and the crystal system are determined by an X-ray diffraction method. The principal refractive indices, n
a, n
b and n
c and the temperature dependence of birefringences, n
c-n
b, n
c-n
a and n
a-n
b, over the temperature range from room temperature to 500degC are measured. A fluorescence spectrum at around 1.06 µm is observed, and strong fluorescence is detected.
Superconducting Character of Nb3Ge Single Crystals
Authors: Matsumoto Yasukuni , Degener Thomas , Heiden Christoph
Published: February 2005

The object of our study was the investigation of the superconducting transition curve of individual crystals in a Nb3Ge film. The growth direction of the A-15 crystals was (100). By using a local four-terminal measuring technique, we successfully recorded the superconducting transition curve of one individual crystal. Increasing the potential probe distance, we obtained a stepped transition curve. These experimental results show that our sample is not homogeneous and each individual crystal has its own superconducting transition temperature. An analysis of the chemical composition was done, too. Finally, the relation between T
c and the stoichiometry is discussed.
Low Barrier Height and Nonuniformity in Al Schottky Contacts on Chemically Etched n-GaAs
Authors: Okumura Tsugunori , Shibata Takeshi
Published: February 2005

The barrier height of Al Schottky-contacts on chemically etched n-GaAs has been relatively low in the as-deposited state but increased by low temperature (50-200°C) annealing. The photoresponse analysis has revealed that the asdeposited Al/n-GaAs interface consisted of the so-called parallel contact with low (0.7 eV) and high (0.9 eV) barrier heights. The dissociation of the lower barrier phase upon annealing has corresponded to the increase in the apparent barrier height determined by the I-V and C-V measurements. The native oxide could be responsible for the lower barrier phase in Al/n-GaAs Schottky diodes fabricated by a standard process.
The Edge Shift, Effective Nuclear Charge and Coordination Stoichiometry: A Novel Correlation
Authors: Khadikar Padmaker V. , Pandharkar Sadhana
Published: February 2005

X-ray absorption edge shifts for a number of cobalt complexes are reported and an empirical correlation between the shift and the effective nuclear charge (Z
eff) of the cobalt atom and the sum of the ligand electronegativity differences from that of cobalt are proposed following regression analysis of the data.
Photoinduced and Thermally-Induced Bleachings of Amorphous Ge–S Film
Authors: Kawaguchi Takashi , Maruno Shigeo
Published: February 2005

Photobleaching and thermal-bleaching of Ge35S65 film were studied on the basis of kinetics for blue shift of optical transmission edge, oxygen depth profiles and far infrared transmission spectra. This study suggests that the photobleaching is associated with both photoinduced intrinsic structural change in the film and photo-oxidation of Ge atom around the film surface. In the early stage, the photobleaching is mainly caused by the photoinduced structural change. The photo-oxidation proceeds gradually and becomes significant in the case of a prolonged illumination in air. It was confirmed, on the other hand, that thermal-bleaching is due to thermal polymerization.
Partially Pinned Boundaries in White Tin Crystals
Authors: Honda Katuhiko
Published: February 2005

The behavior of a dislocation boundary under various applied stresses has been studied by use of the etch hillock technique. The boundary consisted of an array of edge dislocations (the [100](010) slip system) separated with immobile dislocations (the ½<111>{110̄}). Since the motion of edge dislocations was obstructed by immobile dislocations, the boundary as a whole behaved as if it were partially pinned along its length. The boundary bowed between immobile dislocations under a small stress and was released at a certain critical stress. The critical stresses were within a range of about 3 to 20 gw/mm2 for all observed boundaries. Based on a dislocation model already presented, the behaviors of observed boundaries were analyzed by anisotropic elasticity theory and the results were compared with observations.
Precipitated Crystal Grain Size in Nd15Fe77
11B8 and Nd15Fe76Al1
11B8 Permanent Magnets
Authors: Komura Shigehiro , Saga Minoru , Fujii Hironobu , Tuppinger Dieter , Miksovsky Alexander , Rauch Helmut , Hirosawa Satoshi , Sagawa Masato
Published: February 2005

Precipitated crystal grain size in sintered Nd15Fe77
11B8 and Nd15Fe76Al1
11B8 permanent magnets with different heat treatments has been examined by a very small-angle neutron scattering experiment using channel-cut perfect crystals. The results indicate that the chemical microstructures observed are in the range of about 4–6µm, and those in Nd15Fe76Al1
11B8 are larger than in Nd15Fe77
11B8. This simply suggests that the Al-substitution affects the sintering mechanism and results in the increase of the size of precipitates and high coercive force.
Rapid Electron Beam Reacted Tantalum/Titanium Bilayers on Silicon
Authors: Raman V. K. , Mahmood F. , McMahon R. A. , Ahmed H. , Jeynes C.
Published: February 2005

The electrical and structural characteristics of tantalum-titanium bilayers on silicon reacted by electron beam heating have been investigated over a wide range of temperature and time conditions. The reacted layers exhibit low sheet resistance and stable electrical characteristics up to at least 1100degC. Titanium starts reacting from 750degC onwards for 100 milliseconds reaction times whereas tantalum starts reacting only above 900degC for such short reaction times. RBS results confirm that silicon is the major diffusing species and there is no evidence for the formation of ternary silicides. Reactions have also been explored on millisecond time scales by non-isothermal heating.
Effects of γ-Ray Irradiation on Colour and Fluorescence of Pearls
Authors: Matsuda Yasunori , Miyoshi Tadaki
Published: February 2005

The colour of cultured pears of P. fucata can be changed by γ-ray irradiation, which has been applied to pearl processing. The effect of γ-ray irradiation on the colour and fluorescence of pearls was investigated experimentally. The experimental results show that a colour change of pearls to bluish-grey is mainly responsible for a decrease in the reflection factor of the nuclei. Furthermore, a significant change in the fluorescence spectra has been observed for pearls and nuclei. These changes are considered to be caused by the degradation of conchiolin contained in the nacre. Fluorescence from pearls is not affected by the nuclei, but the colour of pears is affected. Thus, the fluorescence method is suitable for investigating the effect of γ-ray irradiation on the nacre.
Measurements of Reflection Coefficient of Ion Waves in an Ion Beam-Plasma System
Authors: Noda Shunichi , Nakamura Yoshiharu , Kawai Yoshinobu , Akazaki Masanori
Published: February 2005

The reflection coefficient of ion waves in an ion beam-plasma system is studied using a bipolar electrode as a reflector. It is found that the reflection coefficient of the beam mode is independent of the pulse widths of incident waves, while that of ion-acoustic waves is a decreasing function of frequency within our experimental accuracy.