bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic roots of Alu-mediated rearrangements leading to cancer
Authors: Gibbons Rosaleen , Dugaiczyk Achilles
Published: February 2005

There are over a million Alu repetitive elements dispersed throughout the human genome, and a high level of Alu-sequence similarity ensures a strong propensity for unequal crossover events, some of which have lead to deleterious oncogenic rearrangements. Furthermore, Alu insertions introduce consensus 3' splice sites, which potentially facilitate alternative splicing. Not surprisingly, Alu-mediated defective splicing has also been associated with cancer. To investigate a possible correlation between the expansion of Alu repeats associated with primate divergence and predisposition to cancer, 4 Alu-mediated rearrangements — known to be the basis of cancer — were selected for phylogenetic analysis of the necessary genotype. In these 4 cases, it was determined that the different phylogenetic age of the oncogenic recombination-prone genotype reflected the evolutionary history of Alu repeats spreading to new genomic sites. Our data implies that the evolutionary expansion of Alu repeats to new genomic locations establishes new predispositions to cancer in various primate species.Key words: Alu repeats, evolution, cancer, primates, splicing, DNA recombination.
Genomic characterization and physical mapping of two fucosyltransferase genes inMedicago truncatula
Authors: Castilho Alexandra , Cunha Margarida , Afonso Ana Rita , Morais-Cecílio Leonor , Fevereiro Pedro S , Viegas Wanda
Published: February 2005

Fucosyltransferases catalyse fucose transfer onto oligosaccharides. Two fucosylated structures have been identified in plants: the α1,4-fucosylated Lewis-a epitope and the α1,3-fucosylated core. Here we report the cloning, genomic characterization, and physical mapping of two genes encoding proteins similar to α1,4-fucosyltransferase (EC 2.4.1.65, MtFUT1) and α1,3-fucosyltransferase (EC 2.4.1.214, MtFUT2) in Medicago truncatula. Analysis of the genomic organization of the fucosyltransferase genes in M. truncatula, revealed the presence of two genomic variants of the MtFUT1 gene coding sequence, one containing a single intron and the other intronless, whereas in MtFUT2, the gene coding region is interrupted by four introns. Using for the first time fluorescence in situ hybridization (FISH) to physically map fucosyltransferase genes in plants, this study reveals a high genomic dispersion of these genes in Medicago. The MtFUT1 genes are mapped on chromosomes 4, 7, and 8, colocalizing on three of the five MtFUT2 loci. Chromosomes 1 and 5 carry the additional MtFUT2 loci. Moreover, the intensity of the FISH signals reveals marked differences in the number of gene copies per locus for both genes. Simultaneous mapping of rRNA genes on chromosome 5 shows that several MTFUT2 gene loci are inserted within the rDNA array. Insertions of coding DNA sequences into the rDNA repeats were never reported to date.Key words: core α1,3-fucosyltransferase gene, α1,4-fucosyltransferase gene, genomic organization, in situ hybridization, Medicago truncatula.
Effect of Secondary Treatments on the Phase Transition of Polydiacetylene LB Films
Authors: Saito Kazuhiro , Saito Mitsuyoshi , Ikegami Keiichi , Kuroda Shin-ichi , Sugi Michio
Published: February 2005

The photochromic behavior of polydiacetylene LB films has been investigated for samples with different secondary treatments. The monomer film is initially converted to the A-type polydiacetylene LB film showing a pronounced red-shifted band and then to the B-type one, depending on the duration time of UV irradiation. Acid vapor treatments, either before or after the initial UV irradiation, show a tendency to hinder the transition from A-type to B-type on the excessive UV irradiation, with the yield of A-type polymer being enhanced. Further, another type of red-shifted band has been found in the case of a successive process; acid vapor treatment→ heat treatment→UV irradiation, which may be dependent on the degree of polymerization. The relation between these results and the yield of polymerization of the films is explained by assuming an order-disorder scheme of the phase transition.
Effect of Radiation and Impurities on Microscopic Deformation Process in PMMA
Authors: Yamashita Tomoyoshi , Shichijyo Shiro , Takemura Tetuo , Matsushige Kazumi
Published: February 2005

Small-angle X-ray scattering experiments were conducted under various tensile stress levels for poly(methyl methacrylate) with different amounts of impurities and microscopic defects. Compared with a highly purified sample of optical fiber grade, the commercially available samples containing many impurities showed that the generation of submicrocracks starts at much lower stress levels. Furthermore, it was revealed that the number and size of such submicrocracks become larger in samples irradiated by γ-rays, which produce internal microscopic defects. These results suggest that such impurities and microscopic defects existing in the virgin samples tend to become nuclei for the submicrocracks upon the application of a tensile stress, causing a significant influence on the microscopic deformation process in amorphous polymers.
Electric Resistance Change Mechanism of Indium-Tin Oxide Film During Deposition of Dielectric Oxide Films by RF Magnetron Sputtering
Authors: Matsuoka Tomizo , Kuwata Jun , Nishikawa Masahiro , Fujita Yosuke , Tohda Takao , Abe Atsushi
Published: February 2005

Electric resistance change of indium-tin oxide (ITO) film was investigated when dielectric oxide films such as Sr(Zr0.2Ti0.8)O3 and Y2O3 for an electroluminescent device were deposited on the ITO by the rf magnetron sputtering method using oxide ceramic targets. In order to understand the mechanism of the resistance change, a dc voltage of -70∼+70 V was biased to an ITO film during the sputtering of dielectric oxide films. The resistance of the ITO film became higher in the positive bias region. The cause of the increase in resistance of the ITO films was confirmed to be oxidation by the oxide targets and the sputtering gas. The amount of the resistance change could be qualitatively explained by the ratio of the oxygen introduced into the ITO film and the combined oxygen forming O2 gas at the ITO surface incident to the ITO film at the sputtering of the dielectric oxide films.
Electronic State of Metalloporphyrins
Authors: Sugahara Masanori , Haneji Nobuo , Imamura Kimitake , Niki Katsumi , Takano Wataru , Kaneda Hisayoshi
Published: February 2005

The electronic states of the oxidized and reduced metalloporphyrins were studied to provide a basis for electronic device applications of the molecules. The effective energy level of the d electron in the metal ion has been found to be \cong 1 eV higher than the HOMO level of the π electron in the porphyrin ring. Fe ions in the Fe porphyrin were found to be irreducible when the temperature was much higher than \cong280 K.
In0.53Ga0.47As/InP Modulation-Doped Heterostructures Grown by Liquid-Phase Epitaxy
Authors: Dai T. A. , Su Y. K.
Published: February 2005

In this paper we present the first report of the study of the characteristics of In0.53Gs0.47As/InP modulation-doped heterostructures grown by liquid-phase epitaxy. Electrical properties were studied by Hall and Shubnikov-de Haas Measurements. A series of doping levels in the InP layer was used to investigate the dependences of mobility and sub-band configuration on sheet carrier density. Mobility enhancements were observed at low temperatures according to Hall measurements. Enhanced electron mobilities were as high as 62000, 60200 and 7410 cm2/Vs at 10, 77 and 300 K, respectively. These are comparable to those obtained by other epitaxial techniques, which indicates that liquid-phase epitaxy is capable of growing high-quality In0.53Ga0.47As/InP heterojunctions.
Effect of AlN Buffer Layer on AlGaN/α-Al2O3Heteroepitaxial Growth by Metalorganic Vapor Phase Epitaxy
Authors: Koide Yasuo , Itoh Nobuo , Itoh Kenji , Sawaki Nobuhiko , Akasaki Isamu
Published: February 2005

AlxGa1-xN(0≦x≦0.4) films grown on sapphires are found to be composed of many mosaic crystallites with various orientations by means of double-crystal X-ray diffractometry. This fluctuation of orientation can be considerably reduced and the surface morphology (smoothness and uniformity) of the film can be remarkably improved by the preceding deposition of the AlN buffer layers. A phenomenological model, which can explain the effect of the AlN buffer layer on the surface morphology and the crystalline quality of AlGaN films, is proposed.
X-Ray Dilatometric Study of Incommensurate-Quasi-Commensurate Phase Transition of Ferroelectric Barium Sodium Niobate
Authors: Uesu Yoshiaki , Fukui Tatsuo , Nagasawa Tetsuro , Shimazu Masaji , Tsukioka Masayuki
Published: February 2005

Temperature dependences of fundamental periodicities of basic lattice, misfit parameter and integrated intensity of an incommensurate spectrum of Ba2NaNb5O15 crystals which were grown by the Bridgman method were precisely measured from room temperature to 300degC by X-ray diffraction method. Small changes in lattice strains and thermal expansions at the incommensurate-quasi-commensurate phase transition at 250degC were detected. The incommensurate spectrum manifests thermally identical behaviors to the previously reported results on crystals grown by the Czochralski method; the sample examined exhibits the quasi-commensurate phase below 250degC with misfit parameter δ=0.008, and large thermal hysteresis.
Radiation Effect due to Energetic Oxygen Atoms on Conductive Al-Doped ZnO Films
Authors: Tominaga Kikuo , Kuroda Kenji , Tada Osamu
Published: February 2005

Al-doped ZnO films were prepared by both RF planar magnetron and RF diode sputterings. The dependence of the ZnO film resistivity on both substrate position and Ar gas pressure was investigated. Energetic oxygen atoms (O atoms) bombarding the film were also observed by time-of-flight apparatus, and the correlation between the film resistivity and the film bombardment by the energetic O atoms was examined. The following results were obtained: When the bombardment of energetic O atoms on Al-doped ZnO films became significant at the substrate positions facing the eroded area of the target, the film resistivity increased at the same positions. Then, both the carrier concentration and Hall mobility of the Al-doped ZnO films were decreased, which was thought to be due to the film bombardment by the energetic O atoms.
Optical Properties of GaAs/AlAs Short Period Superlattices
Authors: Recio M. , Castaño J. L. , Briones F.
Published: February 2005

Low temperature photoluminescence (PL) and photoreflectance (PR) measurements of a set of high-quality short-period superlattices (SPS) GaAs/AlAs with 5-monolayer-thick AlAs barriers and variable width wells in the range of 4 to 10 monolayers are presented. Information on the lowest gap was obtained by PL measurements, and the PR, as we show in this study, contained the information about the lowest direct gap. Calculations based on a simple Kronig-Penney model in which X states in AlAs are confined by higher energy X states in GaAs concur with the experimental measurements obtained. Three new transitions associated with phonon replicas have been observed on the low-energy side of the main photoluminescence peak.
TEM Observation of Electrical Tree Paths and Microstructures in Polyethylene
Authors: Hozumi Naohiro , Okamoto Tatsuki , Fukagawa Hiromasa
Published: February 2005

The starting point of AC electrical trees in polyethylene and the surrounding microstructures were observed by a transmission electron microscope (TEM) for the first time. To minimize the size of tree paths, the authors developed a new apparatus for preparing specimens in which the tree growth was suppressed to less than 10 µm in length. The tree was started from a needle electrode made of carbon-filled polyethylene. The AC tree was a hollow pipe of about 100 nm diameter immediately after its generation. There were constrictions inside the tree, resulting in a corrugated surface. The starting point of the AC tree was a microscopic convex of several tens to one hundred nanometers, which was based on the cohesion of carbon particles of the electrode. The AC tree path was virtually parallel to the lamellae.
Nb/AlOx/Nb Josephson Tunnel Junctions Using Electron Beam Evaporation
Authors: Inoue Atsuki , Nakayama Akiyoshi , Okabe Yoichi
Published: February 2005

Niobium/aluminum-oxide/niobium Josephson tunnel junctions have been fabricated using electron beam evaporation to form all-metal films in a high vacuum system. A quality factor, V
m (the product of the maximum dc Josephson current and the subgap resistance defined at 2 mV) between 36–37 mV, has been obtained for the best junctions of a 6 nm-thick Al layer by cooling down the surface of the base electrode for 100 minutes under a high background pressure, before the deposition of aluminum, after the formation of the base niobium electrode. An array of 80 series-connected junctions has also been fabricated using the selective niobium anodization process and the planarization process. The current-voltage characteristics of the array showed a standard deviation of the maximum dc Josephson current of 3.3%.
Magnetic and Microstructural Properties of Co–Cr Film Fabricated by Continuous Roll Coater
Authors: Yoshida Kazuetsu , Imagawa Kazushige , Honda Yukio , Futamoto Masaaki , Daimon Hideo
Published: February 2005

Co–Cr thin films with a Ge layer between the basefilm and Co–Cr film have been fabricated at a high deposition rate using a continuous roll coater. The effects of the Ge layer and deposition conditions on the magnetic properties and microstructures have been investigated. It is concluded that the Ge layer is remarkably effective in improving the preferred c-axis orientation and magnetic properties, even though the Co–Cr films are fabricated at an extremely high deposition rate. In addition, the tilting angle of the c-axis from the normal of the film plane, which is caused by the oblique incident of the vapor, is affected by the deposition temperature and rate as well as the incident direction of the vapor.
Scattering from Perfectly Conducting Thin Circular Disks: Entire Domain Galerkin Formulation
Authors: Hassan Mohamed A.
Published: February 2005

The electric field integral equations (EFIE) are formulated for the induced surface current, and hence, for the radar cross-section (RCS) of a circular metallic thin disk under plane electromagnetic wave illumination. The equations are then solved by the entire domain Galerkin's method with polynomial basis functions. These functions are taken to be the cartesian product of two Lagrangian interpolation polynomials, one interpolative radially and the other azimuthally. A special treatment for the singularity of the resulting matrix elements is developed. With the present new technique, the RCS at any aspect angle is easily obtained for different disk sizes, for any direction and any polarization of the incident wave, and for both the monostatic and bistatic scattering cases. Numerical results are shown to give good agreement with those obtained by other investigators.
Trichloride Vapour Phase Epitaxial Growth of In1-xGaxAs on InP Using an In/Ga Alloy Source
Authors: Coronado M. López , Abril E. J. , Balaguer R. , Aguilar M.
Published: February 2005

In this paper, we report on the In1-x
Ga
x
As epitaxial layer growth on InP using a Ga/In alloyed source. Lattice-matched In1-x
Ga
x
As can be grown using an In/Ga alloy for 5–9% at. Ga. The influence of different parameters (source and deposition temperatures, the source stoichiometry and the input AsCl3 mole fraction) on the In stoichiometry has been studied in order to obtain the desired stoichiometry within a certain range.
Formation of Cold and Dense Divertor Plasma during Phases of Non-Inductive Current Ramp-Up and Recharging in Tokamak Fusion Reactor
Authors: Hitoki Shigehisa , Sugihara Masayoshi , Yamamoto Shin
Published: February 2005

Possibility of the formation of cold and dense divertor plasma is numerically studied during non-inductive current ramp-up and recharging phases in a Tokamak reactor. When the driving efficiency is high (e.g.∼0.3), the cold divertor plasma of 15–30 eV can be obtained consistent with the non-inductively driven current. In the case of low driving efficiency (e.g.∼0.1), it seems quite difficult to reduce the divertor plasma temperature below 30 eV within a realistic driving power. When the driving efficiency is improved with the main plasma temperature, the possibility to realize the cold divertor plasma is greatly enhanced. In the case of closed divertor geometry, more power is required in order to attain the same plasma temperature at the neutralizer plate.
Analytical Liner Current Distribution and Magnetic Field near Port Section with Circular and Elliptical Shapes
Authors: Shinohara Shunjiro
Published: February 2005

Liner current and electric field distributions are analytically solved, and an induced error magnetic field is numerically calculated near the port section with circular and elliptical shapes using plane geometry. The effect of an elongation ratio of the port cross section and e-folding length of the magnetic field are also studied.
X-Ray Diffraction Microscopy by an Electronic Streak Camera System
Authors: Kojima Takahiro , Noguchi Toshiyuki , Ogawa Tomoya
Published: February 2005

A new electronic streak camera system with an X-ray vidicon was developed here to take topographs or tomographs, using an order of ten minutes for the data acquisition per image (512×480 pixels) with commercially available instruments such as a 2 kW Mo sealex tube, a Lang camera, an X-ray vidicon and a personal computer. Here, the time needed for image processing was a few tens of seconds. Of course, sufficient multiple integration of image data is necessary for improvement of the image quality while the data acquisition time becomes longer as the multiplication is increased. A few ten-minute operation, including the duration of time for image processing, however, is sufficient for good quality images.
Materials for Phase Zone Plate Fabrication for Use with Soft X-Rays
Authors: Fujisaki Hisao
Published: February 2005

Twenty-four elements have been examined to find usable materials for phase zone plates for soft X-rays (0.6–11.4 nm). These are Be, C, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ge, Nb, Mo, Ag, Sn, Sb, Te, Ta, W, Pt and Au. The efficiency of first-order focusing has been calculated as a function of wavelength using available optical constants (Henke et al.: Atomic Data and Nuclear Data Tables 27 (1982) 1). The thickness required to give rise to a phase shift of π radians is also shown as a function of wavelength.
A Method for the Measurement of Electrical Conductivity of Biochemical Materials in vivo
Authors: Dodo Taro , Yorimoto Koji
Published: February 2005

A method of measuring the electrical conductivity of solids (such as biochemical materials) is discussed. The resistance R (Ω) obtained by using a pair of electrodes with the radius a (cm) and the length l (cm) separated at the distance D (cm) gives the conductivity σ (Ω·cm)-1, σ=ln (D/a)/πR
l. The error caused by the difference in the size of material and the electrode separation or the electrode length is investigated. The resistivity of a raw radish is investigated as a function of the frequency as an example of this method. The order of the resistivity is 1 kΩ·cm at low frequency (∼100 Hz) and is 100 Ω·cm at high frequency (∼1 MHz) where the current flow is not impeded by cell membrane.
AlN Ceramics for 10.6 µm Band Hollow Waveguide
Authors: Matsushima Tomoshi , Tanaka Katsuya , Okuda Yoshihide , Sueta Tadasi
Published: February 2005

The complex refractive index of the aluminum nitride ceramics was measured at 10.6 µm wavelength. Then the attenuation constant of a rectangular hollow waveguide with the cross section 2 mm × 2 mm was calculated as 0.02 dB/m. Taking advantage of this low-loss property together with the high thermal conductivity, a trial waveguide CO2 laser was constructed. Maximum output power of 3.1 W (0.44 W/cm) was obtained.
Influence of Oxygen and Metal Oxide Impurities in ZnS:Mn Film on Characteristics of Electroluminescent Devices
Authors: Matsuoka Tomizo , Kuwata Jun , Nishikawa Masahiro , Fujita Yosuke , Tohda Takao , Abe Atsushi
Published: February 2005

The effects of an oxygen and some metal oxide impurities introduced into the ZnS:Mn film at its postannealing process were examined with respect to the characteristics of an electroluminescent device. Depending on the oxygen pressure at the postannealing, the oxygen either decreases the emission threshold field strength in the ZnS:Mn film or forms an additional insulating film such as ZnSO4. The metal oxide impurities Fe, V, and Co caused a decrease in luminance via a killer effect on the Mn emission center. On the other hand, Ti, In, Na, and V decreased the emission threshold voltage by lowering the emission threshold field strength in the ZnS:Mn film.
Fluorescence from Pearls of Freshwater Bivalves and Its Contribution to the Distinction of Mother Oysters Used in Pearl Culture
Authors: Miyoshi Tadaki , Matsuda Yasunori , Akamatsu Shigeru
Published: February 2005

By measuring the fluorescence spectra of pearls from various species of mother oysters, a distinction has already become possible as to whether the pearls are from Pinctada fucata, Pinctada maxima. Pteria penguin or Pinctada margaritifera. In this study, the fluorescence of pearls from freshwater bivalves was measured. The results have made it possible to distinguish freshwater pearls from the other pearls mentioned above.
Planarized Via-Hole Filling with Molybdenum by Bias Sputtering
Authors: Mogami Tohru , Okabayashi Hidekazu , Morimoto Mitsutaka
Published: February 2005

Via-hole filling and surface planarization (planarized via-hole filling) were achieved by molybdenum (Mo) bias sputtering under high (∼80%) resputtering, i.e., high (∼ -600 V) substrate bias voltage, conditions. It was shown that Mo redeposition on the via-hole side walls from the via-hole bottom in the early film deposition stages and Mo redeposition on the bottom from the side walls in the latter film deposition stages played an important role in planarized via-hole filling. Planarized via-hole filling, without sputter-induced damage, was achieved by changing the substrate bias in two steps. The first step was thin layer deposition at a lower substrate bias, to protect the Si substrate surface from severe sputter-etching. The second step was planarized via-hole filling at a higher substrate bias.
Formation of As-Deposited Y-Ba-Cu-O Superconducting Film by a High Temperature Spray Pyrolysis Method
Authors: Nobumasa Hitoshi , Shimizu Kazuharu , Kitano Yukishige , Tanaka Masataka , Kawai Tomoji
Published: February 2005

An as-deposited Y-Ba-Cu-O superconducting film of which thickness was 7 µm was prepared by a spray pyrolysis method without post-annealing procedure. This film showed T
conset at 93 K and T
cend at 25 K. Its surface was smoother than that of a film heat treated at 950°C after the spraying process.
Initial Stages of Negative Point-to-Plane Breakdown in Argon
Authors: Černák Mirko , Hosokawa Tatsuzo
Published: February 2005

Measurements have been made of the initial stage of breakdown in a short negative point-to-plane gap in argon at pressures of 50-600 Torr. The transient glow discharge formation was found to be preceded by a peaked current signal of conspicuous similarity to the Trichel pulse rise and its initail decay in an electron-attaching gas. The results are compared with Morrow's theory of the stepped Trichel pulse.
Electron Temperature Measurement Using Intensity Ratio of H2 Fulcher α(d3Πu-a3Σg) to Hα Emissions in a Weakly Ionized Plasma
Authors: Kondo Katsumi , Okazaki Kiyohiko , Oyama Hitoshi , Oda Toshiatsu , Sakamoto Yuichi , Iiyoshi Atsuo
Published: February 2005

A spectroscopic method for obtaining electron temperature is proposed by observing the intensity ratio of the H2 Fulcher α system (d
3Πu-a
3Σg) and Hα emissions. Experimentally, this method was applied to a weakly ionized plasma produced by a 2.45 GHz microwave source. The obtained electron temperature showed good agreement with the result from the elecrostatic probe.
MBE Growth of GaAs1-xSbx and InyGa1-yAs and Application of BCF Theory to Study the Alloy Composition
Authors: Mochizuki Kazuhiro , Nishinaga Tatau
Published: February 2005

The solid composition of GaAs1-x
Sb
x
and In
y
Ga1-y
As grown on a stepped surface by molecular beam epitaxy is discussed. The experimental results show that the concentration of Sb or In in the epitaxial layer decreases rapidly with the growth temperature and that Sb becomes lower and In higher in concentration with increasing off-angle from the (100) surface. In order to explain these phenomena, the BCF theory is successfully applied.
Electron-Beam Exposure(EBE) and Epitaxy of GaAs Films on CaF2/Si Structures
Authors: Lee Hee Chul , Asano Tanemasa , Ishiwara Hiroshi , Furukawa Seijiro
Published: February 2005

A novel heteroepitaxial method (electron-beam exposure and epitaxy: EBE-epitaxy) has been developed for growing GaAs films on top of CaF2/Si(111) structures. In this method, the surface of CaF2films is modified by an electron beam (e-beam) under arsenic impingement prior to the growth of GaAs films. It has been found that this EBE-epitaxy is very effective in improving the quality of the GaAs films such as surface morphology, crystallinity and crystallographic orientation. The principal effects in the EBE-epitaxy to improve the crystalline quality are considered based on these experimental results to derive a model of the growth mechanism. Other effects, such as electron energy dependence, substrate temperature dependence during e-beam exposure and GaAs growth temperature dependence, are also investigated systematically. Subsequently, the growth condition for an ideal EBE-epitaxy is discussed.
A Very-High-Conductivity of In-Doped CdTe Film
Authors: Hayashi Toshiya , Suzuki Tatsuro , Ema Yoshinori
Published: February 2005

Very-high-conductivity CdTe films were prepared by co-evaporation of CdTe and In. The highest dark conductivity obtained was 103 S cm-1. It is shown that the highest conductivity film contains many In atoms doped interstitially into almost all wide space lattice points and forms a new crystal basis composed of Cd(0 0 0), Te(1/4 1/4 1/4) and In(1/2 1/2 1/2), (3/4 3/4 3/4). The interstitially doped In atoms were stable and did not move from the crystallite into the grain boundary, even when the film was heat-treated.
Microstructure in LB Films of Long-Alkyl Nitroaniline Derivatives
Authors: Inoue Takahito , Yase Kiyoshi , Okada Masakazu , Okada Shuji , Matsuda Hiro , Nakanishi Hachiro , Kato Masao
Published: February 2005

Aggregation states and microstructures of monolayer films consisting of N-octadecyl-2-methyl-4-nitroaniline and icosanoic acid were investigated by electron microscopy and in situ UV spectroscopy. It was found that the nitroaniline derivatives formed their own three-dimensional crystals even in the mixed monolayer, together with small amounts of two-dimensional crystals.
Polarization Characteristics of MOCVD Grown GaAs/GaAlAs CBH Surface Emitting Lasers
Authors: Shimizu Mitsuaki , Koyama Fumio , Iga Kenichi
Published: February 2005

Systematic measurements have been done for the polarization of a vertical cavity surface emitting (SE) laser. The light outputs of the tested devices were linearly polarized and the direction was along the specified crystal orientation. The polarization selectivity is discussed.
Effect of Phosphorus Content of the Magnetic and Electric Properties of Electroless Ni–P Film after Heat Treatment
Authors: Osaka Tetsuya , Usuda Masahiko , Koiwa Ichiro , Sawai Hideo
Published: February 2005

The magnetic and electric properties of electroless Ni–P films after heat treatment are investigated as a function of the P content in the deposit. The residual Ni, which means the surplus Ni (crystallized Ni) after Ni3P formation, is confirmed to determine the film properties of resistivity and saturation magnetization. Moreover, they depend only on the P content and are independent of the preparation conditions. The saturation magnetization, M
s, and the reciprocal of resistivity, ρ-1, are proportional to the amount of the residual Ni after sufficient heat treatment. An equation, showing the correlation between the P content and the resistivity or magnetization of the deposit after sufficient heat treatment, is proposed on the basis of the characters of ferromagnetic and metallic conductivity of the residual Ni matrix.
Polarization Dependence of Reflectivity of Phase-Conjugate Wave Generated by Degenerate Four-Wave Mixing in Bi12SiO20
Authors: Sakai Jun-ichi
Published: February 2005

Reflectivity of phase-conjugate wave generated by degenerate four-wave mixing in a Bi12SiO20 crystal is explicitly represented in terms of an arbitrary incident polarization, externally-applied electric field, and material parameters. The reflectivity is formulated for two typical crystal orientations: grating vector parallel to and perpendicular to the (001) crystal orientation. Maximum reflectivity and the conditions for obtaining it are presented for a given crystal configuration.
Deep Level Induced by Thermal Oxidation in CZ n-Type Silicon
Authors: Hasegawa Takehiro , Matsumoto Satoru
Published: February 2005

A characteristic deep level (E4 trap) is observed only by high-temperature thermal oxidation of CZ silicon and cannot be detected in nitrogen ambient annealing. The E4 trap concentration depends on the position in the wafer. Depth profiles of the E4 trap concentrations vary remarkably with the cooling time. These facts suggest that the E4 deep level originates in the silicon self-interstitial related to the grown-in defects.
Thermally Stimulated Current Measurement in Highly Elongated Polyethylene Film
Authors: Park Dae Hee , Matsuo Masaru , Yoshino Katsumi
Published: February 2005

The trap depth and its density of highly elongated polyethylene have been studied by thermally stimulated current (TSC) measurements. Three discrete traps with depths of 0.13, 0.3 and 0.5 eV have been evaluated using the initial rise method in the temperature region from 77 to 330 K; these change slightly with the elongation ratio. A trap density of the order of 1013∼1014 / cm3 has been calculated from the area of the TSC peaks. The trap density increases upon increasing the elongation ratio and again decreases at a higher elongation ratio; this is consistent with the elongation dependence of the electric conductivity and carrier mobility. The results are discussed in terms of the molecular orientation examined by X-ray diffraction measurements.
A New Method for Producing Step Magnetic Field by Superconducting Magnets
Authors: Shiomi Kakuichi , Matsuzaki Hiroshi , Ohtsuka Mieko
Published: February 2005

A method for producing a step-like change in a magnetic field has been developed. The apparatus used consists of two magnetically coupled superconducting magnets and two superconducting switches, and a sharp step-like transition of the magnetic field is produced in the magnets by operating the switches alternately. The magnets are in the persistent-current mode, and no power supply is required to keep the fields constant. A step-magnetic-field change of 2.1 T is obtained in a time interval of less than a second without any instability. The maximum rate of the change was estimated to be about 10 T/s, which is limited by the low normal resistance and slow thermal response of the superconducting switches. The change rate can easily be increased by more than two orders of magnitude when the characteristics of the switches are improved. The present method is especially useful for obtaining a large and rapid change in the strong magnetic field.
Steady Convection caused by the Temperature Inhomogeneity in a Cylindrical Floating Zone
Authors: Kobayashi Nobuyuki
Published: February 2005

Two convections can be induced by a temperature inhomogeneity in a floating zone. One is a buoyancy driven convection caused by a thermal variation in the liquid density. The other is a surface tension driven convection (Marangoni convection) caused by a thermal variation in the liquid surface tension. Combined steady convections in a cylindrical floating zone were computationally obtained for various combinations of the Grashof numbers and Reynolds numbers due to the Marangoni convection. The Marangoni convection was dominant over the buoyancy driven convection if the zone length was shorter than a critical zone length, and vice versa. The critical zone length on earth was calculated for various liquids.
Effect of Lanthanide Ions on the Properties of Ln1Ba2Cu3O7 Thin Films
Authors: Kanai Masaki , Kawai Tomoji , Kawai Shichio
Published: February 2005

Ln1Ba2Cu3O
y
thin films with nine different lanthanide ions were prepared by a laser ablation method. Systematic changes in the structure and superconducting properties were observed in regard to the difference of the lanthanide ion radii. Smaller lanthanide ions were found to be suitable for the formation of a superconducting film with orthorhombic structure.
The Resistance of Metal Electrode on High-Tc Superconductor YBa2Cu3O7-δ
Authors: Suzuki Morio , Fujii Takashi , Mori Koichi , Muta Kazuya , Watari Takanori
Published: February 2005

The resistivity of five kinds of metal electrodes (Mg, Al, Zn, Ag, and Au) deposited on the high-temperature superconductor YBa2Cu3O7-δ (YBCO) at 5×10-5 Torr were measured. It was found that the resistivity decreases exponentially with at increase of metal work function, and thus qualitatively obeys the rectification theory of metal–semiconductor contact.
The Monte Carlo Calculations for the Distribution Function of Energetic Electrons in a Plane-Parallel Hollow Cathode
Authors: Hashiguchi Seishiro , Hasikuni Mitugi
Published: February 2005

The energy distribution of high-energy electrons was calculated from the plane-parallel hollow-cathode glow discharge of helium gas. Calculations showed an energy distribution function similar to that of a cylindrical cathode whose function had already been obtained by the authors. However, few electrons whose energy equalled the cathode fall potential existed in the central region, contrary to the many electrons in that region in the cylindrical cathode.
Measurement of the Energy Spread of the Cold Relativistic Electron Beam Using Thomson Backscattering of a High Power CO2 Laser
Authors: Kawamura Yoshiyuki , Kawai Masayuki , Toyoda Koichi
Published: February 2005

The energy spread of the cold relativistic electron beam was measured by the Thomson backscattering of a high power CO2 laser. The energy spread was about 1.2% of the total energy. The wavelength and the power of the scattered light were in good agreement with the theoretically calculated values.
Structures and Habits of Manganese Fine Particles Prepared by Gas-Evaporation Technique
Authors: Okazaki Tsugio
Published: February 2005

Manganese fine particles were prepared by gas-evaporation technique and observed by transmission electron microscope (TEM). A new habit of β-Mn was found, which was a truncated rhombic dodecahedron bounded by twelve (110), twenty-four (210) and eight (111). α-Mn and β-Mn with rodlike habits were identified in addition to tetragonal structure. The tetragonal structure of rodlike particles found by Kimoto and Nishida (Jpn. J. Appl. Phys: 6 (1967) 1017) was revised to be a=1.191 nm and c=0.4585 nm. The tetragonal one transformed to α-Mn at nearly 330°C.
The Influence of Aperture Exerting on the Legibility of Multiplexed Dot Matrix TN-LCD
Authors: Kubota Hiroshi , Gomes Cleber Magalhaes , Kobayashi Shunsuke
Published: February 2005

The value of the lightness difference ΔL
* between the displayed part and surrounding background is taken as a figure of merit expressing the legibility. The value of ΔL
* for a multiplexed dot matrix TN-LCD with the contrast mode of W/B (white display with black background) showed a larger value compared with that having the opposite contrast mode, B/W, especially for the transmissive type. The origin of this difference was successfully explained by taking into account the effect of the aperture in each pixel of dot matrix display. From this analysis, the use of the black stripes is recommended.
The Sub-Threshold Characteristics of Polysilicon Thin-Film-Transistors
Authors: Fortunato G. , Meakin D. B. , Migliorato P.
Published: February 2005

It is shown that the sub-threshold characteristics of polysilicon transistors are well described by a model which assumes an exponential gap state density, similar to the ones used for hydrogenated amorphous silicon. The model leads to analytical expressions that give a very good fitting of the experimental data. In contrast, a model based on a simple monoenergetic trap level can in no way account for the observed I
D-V
G characteristics.
Plasma Diagnostics Using Charge Exchange Spectroscopy on the JIPP T-IIU Tokamak
Authors: Ozaki Tetsuo , Kadota Kiyoshi , Fujita Junji , Kitagawa Shiro , Sakurai Keiichi , Oka Yoshihide , Kuroda Tsutomu
Published: February 2005

The ion temperature profile and the density distribution for the beam penetration in the plasma have been measured and evaluated using emissions produced by the charge exchange reaction between a heating neutral hydrogen beam and fully ionized impurities on the JIPP T-IIU tokamak. A 1 m spectrometer with a multichannel detector is used to detect ultraviolet and visible emissions from this reaction. The ion temperature profile during neutral beam heating (or plus ion cyclotron range of frequency heating) is obtained from the Doppler broadening of emission spectra. The central ion temperature agrees with those from other diagnostics. The beam density profile is also in good agreement with the simulational result. The availabilities are demonstrated on this technique to measure the ion temperature and the beam density profile which are necessary to discuss beam heating efficiency and thermal transport.
Effect of Surface Diffusion on the Morphology and Growth Factors of NaCl Crystals
Authors: Maruyama Minoru , Shichiri Takaki
Published: February 2005

In this study, cubic-shaped single crystals and cap-shaped polycrystals of NaCl were grown from vapor and their growth rates were measured. The value of the condensation coefficient on the {100} faces was determined from the growth rates to be 0.25 and 0.10 at ∼600degC and at ∼750degC, respectively. The cap-shaped polycrystals grown spontaneously on a fused quartz substrate at ∼600degC showed large radial growth rates at the initial stages. These were attributable to the effect of surface diffusion of admolecules on the substrate. The mean displacements of admolecules both on the crystal and on the amorphous substrate were estimated in relation to the surface diffusion. The growth mechanism of the cap-shaped polycrystals is discussed.
Behavior of Percolation Clusters in Sintered Mixture of Niobium and Alumina
Authors: Yoshida Katsukuni , Tomii Yoichi , Ueda Sizumasa
Published: February 2005

Percolative behavior of clusters in sintered mixtures of Nb and Al2O3 was observed. The percolation transition occurs when the volume fraction f of Nb is about 0.16 in agreement with the continuum percolation theory. Statistical distributions of the clusters with respect to size and perimeter were also measured with an image processing computer system. After the percolation transition, the cluster distribution becomes broad and discrete, indicating a process of coupling between clusters.
Characteristics of DC SQUIDs Patterned on Highly Granular Y–Ba–Cu–O Thin Films
Authors: Takeuchi Ichiro , Tsai Jaw-Shen , Tsuge Hisanao , Matsuoka Noritsugu
Published: February 2005

Measurements have been made of the properties of thin granular film DC SQUIDs fabricated from the high T
c superconductor Y–Ba–Cu–O, paying special attention to peculiar effects arising from the unique granularity of the film. The output voltage modulation of the SQUIDs was found to be very much lower than expected from the theory, and we present here several possible explanations for it, based on such factors as the asymmetry of the junctions and high kinetic inductance of the film. Multiple periodicities and phase jumps on VΦ-characteristics were observed. Normal operations of the SQUIDs were observed till ∼65 K. Estimating from the best data, the equivalent flux noise was below 3×10-4 Φ0/Hz1/2 in the frequency range above 600 Hz at around 50 K.
Direct Method of Laser Parameter Analysis Using Laser Oscillator
Authors: Tsuchida Eiichi , Sato Heihachi
Published: February 2005

A new method of laser parameter analysis is proposed in which gain parameter G
0, saturation irradiance I
s and a measure of partially homogeneous broadening m are readily determined by measuring the output powers of a traveling-wave-type laser oscillator twice for different intracavity losses without using any probe laser. Applying this scheme to a He–Ne 3.39 µm laser oscillator with a CH4 gas cells as a variable attenuator, G
0=0.417 m-1, I
s=1.36 mW/mm2 and |m|=0.710 (the ratio of the Lorentzian to Doppler line widths, i.e. ΔνL/ΔνD≃0.604) are obtained under 14 mA discharge current of the laser.
Edge and Self-Activated High Band Emission of ZnSxSe1-x Single Crystal Epitaxial Layers
Authors: Zhou Jun , Goto Hideo , Sawaki Nobuhiko , Akasaki Isamu
Published: February 2005

Intense edge and self-activated (SA) emissions have been observed in the ZnS
x
Se1-x
(x>0.41) epitaxial layers grown on (100) GaP substrates. The edge emission shows a peak shift to the high-energy side with an increase in the ZnS molar fraction x and/or a decrease in the temperature. This emission is attributed to the donor(Al)-acceptor(Na) pair emission. The binding energies of the donor and acceptor were determined from thermal quenching curves. The SA band shows a peak shift to the low-energy side with a decrease in the temperature. Its peak energy increases with an increase of x, and is about 0.25 eV higher than that expected for the usual SA emission, showing that this band is due to the SA high band emission.
Modulation Properties of the Single-Mode Laser with a Low-Q Cavity
Authors: Ogawa Tetsuo
Published: February 2005

Modulation characteristics of the single-mode laser with a very low-Q cavity are theoretically investigated. The response functions of the polarization and the population difference to the external pump modulation are obtained to clarify the characteristic frequencies and the modulation bandwidth of this system in the small signal analysis. In the large signal analysis, we employ a forced Toda oscillator model, which is exactly equivalent to the mean-field model of this laser system without the rate-equation approximation. The characteristic periodic solutions of the Toda oscillator system observed in the period-doubling sequence, harmonic and subharmonic oscillations, are studied with the aid of the principle of harmonic balance to understand their nonlinear characters and stabilities. The harmonic oscillation, equivalent to the ordered spiking pulse train of the emission, shows the hysteresis phenomena and the nonlinear resonance. We also present a possible mechanism of the existence of a quasiperiodic mode in the unstable oscillating states observed in the numerical calculation. The stability criteria for the periodic states and the characteristic frequencies of the quasiperiodic modes are analytically obtained.
Thermal Warpage of Large Diameter Czochralski-Grown Silicon Wafers
Authors: Shimizu Hirofumi , Aoshima Takaaki
Published: February 2005

Thermal warping of large diameter Czochralski-grown silicon wafers as affected by oxygen precipitation is investigated both experimentally and theoretically. The difference of wafer warpage and its shape between the heating and cooling processes is clarified by thermal stresses calculated from temperature gradients in wafers for each process. The critical temperatures for the slip occurrence are determined for the heating and cooling processes as a function of the microdefect density. Then, the optimized process conditions to avoid slip dislocations are obtained experimentally. The critical stress curve for the processed wafers in MOS devices is determined by comparison with the thermal stress curves calculated under various process conditions, and thereby predicting the slip-free conditions for wafers in a row with various diameters from 100 to 200 mm.
Characterization of ZnSxSe1-x/(100)Gap Heterointerface by Raman Scattering
Authors: Hayashi Kouji , Goto Hideo , Sawaki Nobuhiko , Akasaki Isamu
Published: February 2005

Heterointerface of ZnS
x
Se1-x
grown on (100)GaP by the chemical vapor deposition (CVD) method is investigated by Raman spectroscopy. It is found that, if the surface morphology of the ZnS
x
Se1-x
epitaxial layer is smooth, the LO-phonon band of the Gap substrate slightly shifts toward the high energy side and becomes broader as compared to the LO-phonon band observed in the as-received GaP wafer. It is shown that these variations are caused by coupling of the LO-phonon and the p-type plasmon, which is produced by the diffusion of Zn atoms during the ZnS
x
Se1-x
growth. If the surface
morphology of ZnS
x
Se1-x
is not smooth, there are no changes in the LO-phonon band, showing that the rough surface degrades the electronic properties of GaP substrate.
Beam Trajectory in Cesium-Beam Primary Frequency Standard and Its Influence on Frequency Stability and Shift
Authors: Nakagiri Koji , Okazawa Haruo , Shibuki Masaaki , Urabe Shinji
Published: February 2005

A simulation of a cesium-beam primary frequency standard, using a beam-trajectory method, is carried out. In the calculations, the following assumptions are made: 1) the beam collimator has a finite area instead of a point source, 2) the effective dipole moment is dependent on the position in the hexapole magnet, 3) the atoms rotate about a beam axis, 4) the beam trajectory falls due to gravity, 5) the first-order Doppler effect and distributed cavity phase difference in the interaction regions of the Ramsey cavity apply. By evaluating the equations and the experimental results, the influence of beam trajectory on beam efficiency, frequency stability and microwave power-dependent frequency shift are examined.
Magnetic Anisotropy of Co Thin Films Prepared by Oblique Incidence II –Effect of Oxidation–
Authors: Cho Jae Kyung , Yamazaki Toshio , Kita Eiji , Tasaki Akira
Published: February 2005

In order to clarify the effect of oxidation on the magnetic anisotropy of a Co thin film, a series of samples were prepared by oblique incidence in an oxygen atmosphere of up to 10-4 Torr. To define the degree of oxidation, the ratio between the total amount of Co atoms in a deposited film and that of Co corresponding to the ferromagnetic moment was considered. The defined oxidation parameter was changed from 0.05 to 0.7 by controlling the pressure of oxygen. It was found that a uniaxial-type anisotropy appeared in the film plane by oxidation, and that a rotational hysteresis was observed below 200 K.
Comparison of Phase Retrieval Methods in Computer Experiments
Authors: Nakajima Nobuharu
Published: February 2005

This paper presents a comparison of the numerical performances of three phase retrieval methods. These methods are Fienup's algorithm. Walker's algorithm from the iterative approach to the phase retrieval problem, and a method using the logarithmic Hilbert transform from the noniterative approach. In computer simulation studies for the reconstruction of two-dimensional object functions, it is shown that a noniterative method produces a unique solution in each case; however, these iterative algorithms stagnate on pseudo-solutions in some cases. Especially, the stagnation of Fienup's algorithm happens more frequently than with Walker's algorithm.
Suppression of Noise in a Discharge Tube by a Minimum-B Type Magnet
Authors: Amemiya Hiorshi
Published: February 2005

It is shown that the placement of a minimum-B type magnet assembly near the anode of a discharge tube is effective in suppressing discharge noise. Observations using an oscilloscope and a spectrum analyzer indicate that the noise amplitude can be decreased by 20 to 40 dB. The electron energy distribution curve, which is distorted by noise, becomes smooth and reliable after the suppression. The merit of the method is that no electric contact is necessary.