bluuebunny/crossref_metadata_2025 huggingface dataset:
A QUANTITATIVE ANALYSIS OF INTERFACIAL AMINO ACID CONSERVATION IN PROTEIN-PROTEIN HETERO COMPLEXES
Authors: REDDY BOOJALA V. B. , KAZNESSIS YIANNIS N.
Published: November 2005

A long-standing question in molecular biology is whether interfaces of protein-protein complexes are more conserved than the rest of the protein surfaces. Although it has been reported that conservation can be used as an indicator for predicting interaction sites on proteins, there are recent reports stating that the interface regions are only slightly more conserved than the rest of the protein surfaces, with conservation signals not being statistically significant enough for predicting protein-protein binding sites. In order to properly address these controversial reports we have studied a set of 28 well resolved hetero complex structures of proteins that consists of transient and non-transient complexes. The surface positions were classified into four conservation classes and the conservation index of the surface positions was quantitatively analyzed. The results indicate that the surface density of highly conserved positions is significantly higher in the protein-protein interface regions compared with the other regions of the protein surface. However, the average conservation index of the patches in the interface region is not significantly higher compared with other surface regions of the protein structures. This finding demonstrates that the number of conserved residue positions is a more appropriate indicator for predicting protein-protein binding sites than the average conservation index in the interacting region. We have further validated our findings on a set of 59 benchmark complex structures. Furthermore, an analysis of 19 complexes of antigen-antibody interactions shows that there is no conservation of amino acid positions in the interacting regions of these complexes, as expected, with the variable region of the immunoglobulins interacting mostly with the antigens. Interestingly, antigen interacting regions also have a higher number of non-conserved residue positions in the interacting region than the rest of the protein surface.
MULTICLASS MOLECULAR CANCER CLASSIFICATION BY KERNEL SUBSPACE METHODS WITH EFFECTIVE KERNEL PARAMETER SELECTION
Authors: NIIJIMA SATOSHI , KUHARA SATORU
Published: November 2005

Microarray techniques provide new insights into molecular classification of cancer types, which is critical for cancer treatments and diagnosis. Recently, an increasing number of supervised machine learning methods have been applied to cancer classification problems using gene expression data. Support vector machines (SVMs), in particular, have become one of the most effective and leading methods. However, there exist few studies on the application of other kernel methods in the literature. We apply a kernel subspace (KS) method to multiclass cancer classification problems, and assess its validity by comparing it with multiclass SVMs. Our comparative study using seven multiclass cancer datasets demonstrates that the KS method has high performance that is comparable to multiclass SVMs. Furthermore, we propose an effective criterion for kernel parameter selection, which is shown to be useful for the computation of the KS method.
EFFECTIVE ALGORITHMS FOR TAG SNP SELECTION
Authors: LIU TIE-FEI , SUNG WING-KIN , LI YI , LIU JIAN-JUN , MITTAL ANKUSH , MAO PEI-LIN
Published: November 2005

Single nucleotide polymorphisms (SNPs), due to their abundance and low mutation rate, are very useful genetic markers for genetic association studies. However, the current genotyping technology cannot afford to genotype all common SNPs in all the genes. By making use of linkage disequilibrium, we can reduce the experiment cost by genotyping a subset of SNPs, called Tag SNPs, which have a strong association with the ungenotyped SNPs, while are as independent from each other as possible. The problem of selecting Tag SNPs is NP-complete; when there are large number of SNPs, in order to avoid extremely long computational time, most of the existing Tag SNP selection methods first partition the SNPs into blocks based on certain block definitions, then Tag SNPs are selected in each block by brute-force search. The size of the Tag SNP set obtained in this way may usually be reduced further due to the inter-dependency among blocks. This paper proposes two algorithms, TSSA and TSSD, to tackle the block-independent Tag SNP selection problem. TSSA is based on A* search algorithm, and TSSD is a heuristic algorithm. Experiments show that TSSA can find the optimal solutions for medium-sized problems in reasonable time, while TSSD can handle very large problems and report approximate solutions very close to the optimal ones.
Secondary Electron Multiplier as a Detector of Very Feeble Ion Current down to 10-19 Amperes
Authors: Michijima Masami
Published: November 2005

A 12-stage Cu–Be electron multiplier was constructed for detecting very feeble ion current. General characteristics of the multiplier coupled with a vibrating reed electro-meter were investigated by measuring the output of a high vacuum mass spectrometer. The stability of the multiplier gain was sufficient for the measurement of isotope ratios. For example, the 20Ne/22Ne ratio was found to be 10.563±0.006 (un-corrected for mass discrimination).
At an ultimate pressure of 10-8 Torr in this mass spectrometer, background mass spectra up to M/e 150 were recorded, and some hydrocarbon fragment peaks corresponding to 10-16–10-18 amperes were found in C2–C7 groups. Mass peaks below 10-16 amperes fluctuate considerably, but such statistical fluctuations may be smoothed out by using an amplifying system with a sufficiently long time constant and a low scanning speed. Under such conditions, an ion current down to 1×10-19 amperes was distinguishable over the noise level of the amplifying system.
A Multichannel Pulse Height Analyzer Using Parametron Logic
Authors: Hayashi I. , Ōtsuka M.
Published: November 2005

A time conversion type 256-channel pulse height analyzer, which makes use of a parametron memory circuit, has been constructed. The memory cycle has been reduced to 100 µs by means of a novel logical circuit. An analog-digital converter of the pulse height analyzer can analyze pulses, which come simultaneously from up to eight different counters, and can sort pulses from a counter into up to eight groups, in accordance with coincidence inputs from other counters.
Design of High Power Electromagnets
Authors: Ishikawa Yoshikazu , Chikazumi Sōshin
Published: November 2005

This paper consists of three parts: In Part I, the general principles of electromagnet design are discussed, particularly the shape of pole pieces suitable for attaining a simultaneous saturation magnetization throughout the pole and also suitable for producing a strong field at the center of the pole gap. In Part II, a practical procedure for designing an electromagnet is discussed on the basis of economical considerations. In Part III, the actual designs of a bent double-yoke magnet and a large Bitter-type magnet are presented together with experimental data on the completed magnets.
Permeation of Helium Gas through Glass
Authors: Kawasaki Koji , Senzaki Kiyoshi
Published: November 2005

By using ultra-high vacuum techniques and an analysis tried by Rogers et al., helium permeation rates, diffusion coefficients, and solubilities for three different glasses have been determined in the region of temperature from 50°C to 350°C.
The permeation rate has been related to glass composition, and it has been found that a molybdenum seal glass investigated is suitable for the use in ultra-high vacuum system.
Dee Voltage Stabilizer for the INS Variable Energy Ordinary Cyclotron
Authors: Suwa Shigeki , Suzuki Arata , Yamada Takanobu
Published: November 2005

A dee voltage stabilizer of grid control type was constructed for the INS variable energy ordinary cyclotron. With this stabilizer the dee voltage has been kept constant within 0.3% and the intensity modulation of the external beam has been practically eliminated.
A Pulser Circuit for the Synchro-Cyclotron Oscillator
Authors: Suzuki Arata , Yamada Takanobu
Published: November 2005

A circuit was built for the oscillator of a synchro-cyclotron, with which oscillator can be stopped and started at a desired instant during the frequency modulation cycle. By reducing the duration of the oscillation to one fifth of the whole cycle the dee voltage was successfully raised during acceleration without increasing the mean radio frequency power loss. In this way the beam intensity at the scattering chamber was increased by a factor of two, and a stable beam up to 0.3 µA was obtained within an area of 0.2 cm2.
Magnetic Moments of Some Mixed Rare Earth Iron Garnets
Authors: Perel Joseph , Schieber Michael
Published: November 2005

The maximum amount of substitution of La, Pr and Nd and the saturation magnetization of La, Pr, Nd, Sm and Eu substitutions in the iron garnets of Lu, Yb, Tm and Er was measured. It was found that in a formula R3-x
M
x
Fe5O12 where R=Lu, Yb, Tm and M=La, Pr or Nd the maximum value of x which can be substituted in the garnets was x=0.50 for La, x=1.50 for Pr (x=1.35 for Pr in Er.I.G.) and x=1.85 for Nd (x=2.00 for Nd in Lu.I.G.). The sign of the magnetic moment of the mixed rare earth ions relative to the net iron magnetization was determined. It was found that Pr3+ or Nd3+ are parallel whereas Eu3+, Er3+, Tm3+ and Yb3+ antiparallel to the net iron magnetization. For Sm3+ a small magnetic moment is guessed and discussed.
Re-examination of the Thermal Expansion of the Ferroelectric Triglycine Sulfate
Authors: Shibuya Iwao , Hoshino Sadao
Published: November 2005

The temperature dependence of the thermal expansion coefficients of a single crystal of ferroelectric triglycine sulfate was measured through the Curie point by both X-ray diffraction and dilatometric methods. The results of the measurements were compared with the corresponding data independently obtained by Ezhkova et al. and by Ganesan. Thermal expansion coefficient vs. temperature curves obtained by the X-ray measurement and by the dilatometric method are in good agreement with each other and no effect of the radiation damage (as reported by Ganesan) was found. The discrepancies among the results measured by various workers may be explained by the consideration of the accuracy of measurements. It is concluded that the essential feature of the thermal expansion of triglycine sulfate is not affected by a moderate dosage of X-rays.
A Hot Plasma Produced by a Linear Discharge Device with a Large Capacity Condenser Bank
Authors: Enjōji Hiroshi , Okamoto Kousuke , Ishibe Yukio , Sakamoto Yūichi , Furuichi Akio , Mori Kazuo , Andou Kouzou
Published: November 2005

A linear discharge plasma is studied which is produced by means of an electrolytic condenser bank of a large capacity (1.1×104-1.3×105 µF) and of a low working voltage (500V). The discharge current is non-oscillatory. The maximum values of the discharge current, the duration of discharge and the rate of increase of the discharge current are 100kA, 4.5 ms and 109 A/s respectively. Observation by means of search coils and a magnetic probe reveals that the plasma is helical, the helix rotating and expanding, finally to touch the inside wall of the tube. The effect of the axial magnetic field on the discharge current is studied. The electron density n

e
and the electron temperature T

e
(in terms of eV) as estimated by microwave measurement and spectroscopic observation are L: n

e
(microw.)>1012 electrons/cm3, n

e
(spectr.) 1015 electrons/cm3; T

e
(microw.) 40 eV, T

e
(spectr.) 10–20 eV.
Dynatron-Type Negative Resistance Observed in the Collector-Voltage-Saturation Region of the Junction Transistor
Authors: Nakahara Osamu
Published: November 2005

Experimental results on the dynatron-type negative resistance observed in the collector-voltage-saturation region of a certain type of junction transistor have been discussed with a theoretical model. The phenomenon is interpreted as the result of the appreciable conductivity modulation of the base resistance in the saturation region, since it modulates the injection density at the emitter through feedback effect of the base resistance. Theoretical calculations were carried out based on a simple model and compared with the experimental data. Discussions on the results inclusive of the comparison with the similar phenomena in the field-effect transistors are given.
The Phase Transformation of Iron Rich Iron-Nickel Alloy in Fine Particles
Authors: Kachi Sukeji , Bando Yoshichika , Higuchi Seijun
Published: November 2005

Studies on the equilibrium diagram and characteristics of phase transformation of Fe-Ni alloy in fine particles were carried out by X-ray diffraction and specific heat measurement. The specimens were prepared by reduction of solid solution Fe
x
Ni1-x
C2O4 in hydrogen at various temperatures below 800°C. The fine particles reduced at temperatures below 600°C did not undergo a martensitic transformation even when they were cooled to room temperature. The diagram determined by the reduction method is in close agreement with those obtained by annealing of bulk alloys for very long periods. Therefore the diagram was easily determined because of the absence of martensitic transformation and furthermore because of the acceleration effects during reduction upon the diffusion rate. The existence of the superstructure Fe3Ni was suggested by the specific heat measurement.
Etch Patterns and Dislocation Etch Pits on Germanium with KI-I2 Redox System
Authors: Arizumi Tetsuya , Akasaki Isamu
Published: November 2005

Dissolution of Ge proceeds through the oxidation of Ge by iodine. The etching rate is several hundred µg/cm2hr with the activation energy being approximately 0.22e
V/molec. and it is in the order: {100}>{110}>{111}. The etchant develops three-, two- and four-fold symmetrical patterns, bounded by {111} planes of the slowest etching rate, on the surfaces {111}, {110} and {100}. Several varieties of etch pits show the anomalies of dislocation.
Source d'ions pulsée du type haute fréquence
Authors: Tsuchimoto Takashi , Hara Eiichi
Published: November 2005

A mesh grid is introduced to high frequency ion source for production of pulsed ion beam, and the characteristics of mesh grid potential to ion beam current show that there is a remote cut-off potential at the point of probe potential plus 1.2 kv. The beam output current can be gradually and continuously changed by changing the potential of the mesh grid. The obtained pulsed beam figurestare detected by using magnetic pick up probe of pulse-transformer-type. The cause of the remote cut off is also discussed.
Induced Radioactivity in Iron by High Energy Protons
Authors: Lin I , Toyoda Toshiyuki
Published: November 2005

It will be very important to take into account radioactivity which is induced in various materials when we plan to build high intensity proton accelerators. Focusing our attention on the problem of induced radioactivity in iron, we have made theoretical estimates of radiation doses, which seem to be useful for designing high intensity machines, for example, a 12 GeV 1∼30 µA proton synchrotron. Since experimental data concerning spallation cross sections are scarcely known, it is necessary to extrapolate them. The Monte Carlo calculation was applied to cascade effects for several reasons. Although a high intensity accelerator such as the 12 GeV 1 µA proton synchrotron, has not yet been built, some discussion might be possible in comparison with recent observations on induced radioactivity in iron at the CERN Proton-Synchrotron and Synchro-Cyclotron.
New Magnetic Pickup Probe for Charged Particle Beams
Authors: Yamada Ryuji
Published: November 2005

A new transmission-type current monitor of high sensitivity and accuracy has been developed in order to measure the total intensity of a pulsed beam. The method has been applied to a linac beam. This method causes no interference with the beam and its sensitivity is independent of the beam energy. The system essentially consists of a magnetic core and a feedback amplifier. The beam passes through a window of the magnetic core, and the signal induced in of a pickup coil wound on the core is amplified and negatively fed back to another coil wound on the same core. The total number of ampere-turns is thus automatically made equal that due to the beam current. The voltage generated across a resistor by this feedback current is proportional to the instantaneous total current of the beam and accurately reproduces the current waveform. An output voltage pulse of 0.5 volt can easily be obtained for a beam of 1 mA peak.
Electro-Optical Properties of Nematic Liquid-Crystal Films
Authors: Ohtsuka Tetsuro , Tsukamoto Masahide
Published: November 2005

Electro-optical properties of two nematic liquid-crystal compounds, p-cyanobenzal-p'-anisidine and p-cyanobenzal-p'-phenetidine, are investigated. The compounds have the electro-optical properties which are different from those found in p-azoxyanisole and anisylidene-p-aminophenylacetate. These properties are the characteristics of a nematic liquid-crystal compound whose molecular dipole moment lies nearly along its long molecular axis. When a voltage is switched on or off, the transmitted-light intensity through the nematic film in the direction parallel to the applied electric field oscillates in a certain short duration. The oscillating phenomenon is independent of the frequency of the applied electric field. It is found that the spontaneous alignment parallel to the surface by wall effects is important for interpreting the oscillating phenomenon of the nematic liquid-crystal films. An interpretation of the result is suggested.
Properties of GaP Red-Emitting Diodes Grown by Liquid-Phase Epitaxy II. Effect of Substrate Orientation
Authors: Naito Makoto , Kasami Akinobu , Toyama Masaharu
Published: November 2005

Emission efficiency and reproducibility of GaP red-emitting diodes are improved by removal of a deteriorated layer of a p-type substrate by dissolution in the epitaxy solution just before growth of an n layer. Employment of this procedure enables investigating the effect of substrate orientation. The optimum tellurium concentration for diodes grown on (111)Ga surface of the substrate is 2∼2.5 times higher than that grown on (111)P surface, and the emission intensity at the optimum Te concentration is 1.5∼1.8 times stronger in the latter case. These results are explained by the difference in the impurity distribution near the p-n junction owing to out-diffusion of zinc atoms from the substrate into the epitaxial layer. An external quantum efficiency of 2.7% has been attained without antireflection coating by growing a tellurium and oxygen doped n layer on (111)P surface of a p-type substrate sufficiently etched by the epitaxy solution.
Structure of Film Prepared by Low Energy Sputtering of Molybdenum
Authors: Nagata Saburo , Shoji Fumiya
Published: November 2005

Dependence of the structure and electrical resistivity of sputtered molybdenum films on residual gas pressure, ion energy, ion current density and substrate temperature are investigated in detail. Fcc structure is obtained when the residual gas pressure is high and the deposition rate is low. The film structure is bcc on substrates at 500°C, while the film of fcc structure does not transform to bcc when it is heated up to 700°C in vacuum. The lattice constant of fcc structure coincides with that of γ-Mo2N obtained by reactive sputtering. From these results, it is concluded that the film of fcc structure is γ-Mo2N.
Behaviors of Eutectic Crystals below Their Eutectic Points (II)
Authors: Tino Yosiaki , Asahi Nobuo
Published: November 2005

It is found that the crystal growth of silicon in contact with iron is possible below the eutectic points of the iron-silicon binary system. It is also noteworthy that the behavior of crystal growth in the case above mentioned is quite similar to the crystallization of silicon in the gold-silicon system at a temperature much higher than the gold-silicon eutectic point. Such findings will be explained by considering the similarity between the gold-silicon equilibrium phase diagram and a meta-stable iron-silicon phase diagram proposed by the present authors.
Frequency Response of Metal-Insulator-Metal Tunnel Junctions
Authors: Nagae Moichiro
Published: November 2005

Time-dependent tunneling currents in response to small input voltages applied to biased metal-insulator-metal tunnel junctions are calculated by means of the linear response theory based on the transfer Hamiltonian model for the direct electron-tunnelings. An exponentially decaying factor exp
(-t/τ), where τ is a life time of a Bloch electron caused by scattering, is introduced into the formula for each elementary current due to a single tunneling-transition of an electron. Nevertheless, the terms including such a decaying factor completely cancel each other in the expressions for the main parts of the resultant tunneling-current responses. The time lags of the responses turn out to be much less than τ.
Measurements of Lags in Vidicons Using GaP Red-Emitting Diodes as a Light Source
Authors: Shimizu Kazuo , Iwasawa Mineo , Yoshida Okio
Published: November 2005

A novel apparatus for measuring lags in vidicons using GaP red-emitting diodes as a light source is described. By using GaP diodes, the light source becomes compact and the whole measuring system is controllable electrically. Furthermore, measurement can be carried out under the condition of appropriate timing or delayed timing, where the change of light levels occurs just after scanning of the electron beam of vidicons or at a somewhat delayed time. Some of the measured results are also shown.
Some Observations on Nickel Oxide Scale
Authors: Terao Nobuzo
Published: November 2005

The oxide scales formed on impure nickel and high-purity nickel by heating in air at 1100°C are compared. Multiple layers, particularly triple layers in this work, are observed to be formed on the impure nickel. It is shown, by microhardness measurements and electron probe microanalyses, that the chemical composition of the different oxide layers is not the same. The ratio between the oxygen and the nickel content is larger in the outer layer than in the inner layer. On the other hand, the oxide scale formed on the high-purity nickel consists of one homogeneous layer. Some points of view on the mechanism of oxidation are discussed.
Accuracy of Beam-Bending Method for Viscosity Measurement of Glass
Authors: Kimura Tomisi
Published: November 2005

Accuracy of the beam-bending method used in viscosity measurements of glass is determined by using electric-melting fused quartz. Average viscosity of ten specimens is obtained as (5.96±0.16)×1012 poise at 1200°C with the standard deviation of 8%. Limits of specimen dimensions applicable in this method is determined by using Hario 32, one of the most commercial types of glass. The available viscosity range by the method is 107 to 1015 poise. Viscosity-temperature relation for Hario 32 is given from 500 to 850°C.
Effect of Heterogeneity of a Conducting Fluid on the Performance of a MHD Generator
Authors: Chandrasekhara B. C. , Rudraiah N. , Kuchela K. N.
Published: November 2005

The effect of heterogeneity of a conducting fluid on the performance of a liquid metal generator is considered. The results of the investigation show that the density stratification increases the electrical efficiency as well as the output power of the generator for a given aspect ratio. The results are compared with the performance of a generator using homogeneous fluid.
Structural Analyses of the β and γ Alloys of Al-Mg
Authors: Taketoshi Kazuhisa
Published: November 2005

The atomic positions of the β and γ phases of Al-Mg alloys are determined, and the kinds of atoms corresponding to them are assigned by taking account of the difference of atomic radii between Al and Mg. The structure of the β phase is cubic with a unit cell containing 108 atoms. The space group, the lattice parameter and the average coordination numbers are Pm3m, 12.419 Å and 12 respectively. The structure is a superstructure of fundamental f.c.c. arrangement. The observed satellite spots are essentially explained by the displacement of atoms from average positions. The structure of the γ phase is cubic with a unit cell containing 54 atoms. The space group is Im3m, and the lattice parameter is 10.437 Å. The structure is a superstructure of fundamental b.c.c. arrangement.
Single Crystal Growth of Se-Te Alloys onto Tellurium from the Melts
Authors: Shiosaki Tadashi , Kawabata Akira
Published: November 2005

The method to obtain single crystals of Se-Te alloys is developed. In this method, it is possible to grow a single crystal of an alloy from the melt, using a single crystal of tellurium as a seed for a Bridgmanlike method. The crystal is grown epitaxially onto tellurium. The obtained crystals is homogeneous except the layer of a few mm thick on the substrate. Single crystal growth at reasonable rates is limited to the alloys containing less than about 30% tellurium because of constitutional supercooling problem.
The cross area of an ingot obtained by this method is the same as that of a tellurium substrate, whose large crystal is prepared comparatively easily, and 30 mm long alloy crystals of 12×15 mm2 cross area are obtained easily.
Microwave Anisotropy and Frequency Dependence of Hot Electron in n-Type Gaps
Authors: Kaneda Shigeo , Abe Masayuki
Published: November 2005

The physical mechanism of the microwave anisotropy due to the hot electron effect in a semiconductor bulk is at first investigated phenomenologically for the case that a relative spatial angle θ between a small microwave electric field and a high intensity electric bias field is arbitrary. And then, the microwave anisotropy and the frequency dependence inn-type GaAs are analyzed by using the Boltzmann transport equations. Conclusively, the microwave anisotropy is especially remarkable in the region of negative resistance. Furthermore, as an interesting result, the dependences of both the microwave angular frequency ω and the angle θ in the microwave characteristics are monistically determined by only one factor \varOmega≡ω/cos θ under the proper condition of ωτ (τ: relaxation time), which is satisfied in the region of negative resistance.
Optical Constants of HgTe and HgSe
Authors: Moritani Akihiro , Sekiya Hideki , Taniguchi Kenji , Hamaguchi Chihiro , Nakai Junkichi , Makabe Ryoji
Published: November 2005

The optical constants of HgTe and HgSe are determined in the photon energy region 1.7∼3.5 eV from ellipsometric measurements at room temperature. The structures associated with the E
1 and E
1+Δ
1 band edges are found in the extinction coefficient spectra at energy values nearly coincident with the data of the normal incidence reflectivity for both materials. Tentative surface film corrections are made at several photon energies.
Electrochemical Synthesis and Photovoltaic Effect of Copper Sulfides on CdS Single Crystals
Authors: Nakayama Nobuo , Gyobu Atsuo , Morimoto Nobuo
Published: November 2005

Copper-sulfide layer is electrochemically produced on CdS single crystals in copper ion solution with various bias current densities. The compositions and structures of the copper sulfides are determined by means of the X-ray powder and single crystal methods. The phases of the copper sulfides formed on CdS crystals change not only by the bias electric current density but also by the temperature of solution. On examining the photovoltaic effects for all combinations of the copper sulfides and CdS, it is shown that the best combination for the solar cell is the Cu2S-CdS pair.
Discharge Current Noise in DC Excited Ar+ Lasers
Authors: Suzuki Takeo
Published: November 2005

Properties of the noise caused by an anode oscillation in a DC excited Ar+ laser are investigated. It is revealed from simple considerations and experiments that the amplitude of the noise caused by the anode oscillation is inversely proportional to ballast resistance. Frequency response of current fluctuations to laser fluctuation is calculated and compared with experimental results.
The condition for suppressing the anode oscillation is examined experimentally.
On the Resolving Power of a Three-Stage Bennett Type Radio-Frequency Mass Spectrometer
Authors: Lall H. B.
Published: November 2005

This article deals with the improvement of resolving power of a three-stage aperiodic radio-frequency mass spectrometer by superimposing the second harmonic on the fundamental frequency of the sine-wave form of the r. f. voltage. The expressions for the energy gain and resolving power have been derived and analyzed. The dependency of energy-gain and resolving power on the co-efficient of the amplitude of the added harmonic has been investigated. Mathematical analysis of resolving power yields results contrary to those predicted by the single-stage theory. The parameters which improve the performance characteristics have been investigated.
Projected-Range Straggling of 4- to 24-MeV Electrons in Elemental Materials
Authors: Tabata Tatsuo , Ito Rinsuke , Okabe Shigeru , Fujita Yoshiaki
Published: November 2005

By modifying the derivative of the empirical expression of Ebertet al.for the transmission curve, an empirical equation is developed which expresses the projected-range straggling (PRS) distribution of electrons in the semiinfinite medium as a function of depthx, incident energyT0, and atomic numberZof the absorber. Values of constants in this equation are determined through least-squares fit to the experimental data of the present authors for 4.09 MeV≤T0≤23.5 MeV and 4≤Z≤79. The ratio of the PRS parameterΔR(full width at half-maximum of the PRS distribution) to the most-probable projected range is found approximately to be expressed by a power function ofZ2/T0. An empirical relation which expressesΔRas a linear function of the extrapolated, the projected, and the most-probable projected range is also given.
Transient Phenomena Caused by Temperature Change on Capacitance of Ti-TiO2-Metal Systems
Authors: Yamazaki Masaki , Nozaki Hiroshi
Published: November 2005

Anodic TiO2 (anatase) films are formed on titanium. Then the heat treatment is done in air at 150°C for 5 hr. Capacitor-like Ti-TiO2-metal samples are constructed with Ag, Au, Al, and In counterelectrodes. It is found that the capacitance or the samples shows transient phenomena when the temperature is rapidly increased or decreased, and these transients are not counterelectrode dependent. Thus, the transients are investigated over the range from 25 to 100°C. The relaxation times (τ) of the transients are examined at the several temperatures; the relaxation times at 50, 75, and 100°C are 35, 27, and 22 min, respectively. An Arrhenius plot of log
1/τ vs. 1/T indicates that the energy of activation for the transients is about 2 kcal/mol.
Electrical Properties of Semiconductor Photodiodes with Semitransparent Films
Authors: Kondo Ryuji , Okimura Hiroshi , Sakai Yoshio
Published: November 2005

High speed photodiodes with semitransparent film-semiconductor junctions, which behave as Schottky barriers, are designed and prepared. The optimized width of the depletion layer of the photodiode is calculated for the selected cut-off frequency. The relations between transmittance and sheet resistivity are studied with some films of semiconducting compounds, which affect the gain and response time of photodiodes.
The photodiodes, fabricated by the deposition of the semitransparent films of CdS or CU2Se on Si, have high frequency response and the cut-off frequency of Cu2Se-n.Si photodiodes is higher than 4 GHz.
Time Behavior of Pulsed Gain at 337 µm of HCN Laser
Authors: Yamanaka Masanobu , Yamauchi Takashi , Yoshinaga Hiroshi
Published: November 2005

The time behavior of pulsed gain at 337 µm of HCN laser is investigated. The absorption pulse is observed in the pulsed current of a width of 3 µs. This means that the HCN molecules are already produced in an electrical discharge through gases with H, C and N atoms, and that the population of the upper laser level is instantaneously smaller than that of the lower level. The decay time of the pulsed gain, which is as long as 40 to 80 µs, is no measure of the life time of the upper laser level. This is confirmed by the fact that theQ-switching of the pulsed 337 µm HCN laser gives almost no increase in output over the normal pulsed output which may be due to the fact that life time of the upper level is as short as a few µs.
The Effects of Oblique Incidence and Non-Monochromaticity on Visibility of Interference Fringes
Authors: Nayyar V. P. , Virdi S. P. S. , Mehta B. L.
Published: November 2005

The authors study the effects of the size of the aperture, through which the light enters the interferometer and of the finite width of the spectral line on the visibility of two beam interference fringes. Both the cases of narrow slit and circular aperture are considered.
The Selective Epitaxial Growth of Silicon by Using Silicon Nitride Film as a Mask
Authors: Ogawa Hiroshi , Nishinaga Tatau , Kasuga Masanobu , Arizumi Tetsuya
Published: November 2005

The selective epitaxial growth of Si through the window in silicon nitride film is studied for the SiCl4-H2 system. Experiments prove that the silicon nitride film is extremely stable compared with the usual silicon dioxide film.
To find out the necessary conditions for the selective epitaxial growth, the growth rates of Si on silicon nitride film and on silicon bare surface are obtained independently from the experiment. The critical SiCl4 pressure for the nucleation on silicon nitride film is determined as a function of growth temperature. The experimental results are explained by the nucleation theory.
Epitaxial Growth of α-SiC from the Vapor Phase
Authors: Minagwa Shigekazu , Gatos Harry C.
Published: November 2005

Epitaxial layers of α-SiC are grown on the (0001) and the (0001̄) faces of α-SiC substrates front the silane-propane-hydrogen system. The structure, morphology and growth rate of the layers are studied as a function of the partial pressures of the reactants and the substrate temperature. It appears that the growth process is controlled by the combined effects of propane diffusion and the rate of thermal etching of SiC. The best layers in terms of surface smoothness and crystalline perfection are obtained under low reactant partial pressures (slow growth rate conditions) at temperatures in the vicinity of 1550°C. The epitaxial layers are structurally characterized with X-ray diffraction techniques, electron scanning microscopy, and chemical etching. As grown layers exhibited n-type conduction. p-type boron doped layers are grown by using borane gas in the reactant system. Light emitting p-n junctions are prepared and electrically characterized.
Hypersonic Attenuation in Sb Doped Germanium
Authors: Miyasato Tatsuro , Akao Fumio , Ishiguro Masakazu
Published: November 2005

Hypersonic attenuation in Sb doped Ge is measured. In the attenuation vs. temperature curve, a large peak is found at 1.8°K. A hypersonic sournd used is longitudinal waves of 1 GHz propagating along the <111> axis of Ge crystal which contained about 1×1014, 1×1015 and 1×1016/cm3 donors.
The above attenuation peak seems to be due to the electronic relaxation between the singlet and the triplet states of the donors in Ge, as discussed by M. Pomerantz in the case of As- or P-doped Ge.
Design of an Apparatus for X-Ray Intensity Measurement on a Weissenberg Photograph by the Use of Two ITV Cameras
Authors: Izumi Takatoshi
Published: November 2005

An apparatus for X-ray intensity measurement on a Weissenberg photograph is designed. The main features of this apparatus are as follows: (1) Two ITV cameras are used, one for a Weissenberg photograph and the other for an indexing chart. The former is used for intensity measurement. Indexing of the photograph can be easily made on a monitoring TV by superimposing the indexing chart on the photograph. (2) This apparatus is relatively simple, and the accuracy in the intensity measurement appears sufficient for an ordinary structure analysis.
Electron Microscopic Study on the Structure of TinO2n-1 (4≤n≤10) Phases
Authors: Terasaki Osamu , Watanabe Denjiro
Published: November 2005

Transmission electron microscopy and diffraction study of the homologous series of oxides Ti
n
O2n-1 (4≤n≤10) reveals that the structures of these oxides are derived from rutile by regular crystallographic shear on planes parallel to (121), as previously suggested by Andersson and Jahnberg (Arkiv Kemi. 21 (1963) 413). Electron microscope images clearly show microstructures. Micro-twin structures of fine scale are observed very often for specimens with n≥7 but never detected when n≤6. The interface plane of the twin bands is parallel to the (200)
r
in most cases, although the twin structure with the interface plane (002)
r
or (020)
r
is seen occasionally. A mode of two phase mixture for the specimen in the two phase region is clarified.
Calorimetric Studies on Chemisorption of Nitrogen on Tantalum
Authors: Yamazaki Hisashi , Oguri Takeo , Kanomata Ichiro
Published: November 2005

Behaviors of chemisorption of wires and ribbons are studied with Roberts' type adsorption calorimeter. The total saturation coverages are 3.8×1014 molecules/cm2 for both wires and ribbons. Initial values of average sticking probabilities are 0.22 for the wire and 0.20 for the ribbon at room temperature, and average sticking probabilities abruptly decrease at about 1.7×1014 molecules/cm2. Average calorimetric heats also vary with the increase of coverage as 6.7, 6.0 and 5.2 eV for the wire, and 7.3 and 5.4 eV for the ribbon.
Properties of the chemisorption states of B1, B2 and B3 are made clear by the multiplex state theory using the above average values. In the B1-state, the sticking probability is very small such as 0.01 and the heat of chemisorption is also small such as 5.3 eV. These values for the B2-state are 0.37 and 6.0 eV. The B3-state has the largest values of 0.5 and 7.3 eV.
The heat of chemisorption of 6.1 eV calorimetrically obtained on an evaporated film is identical with that of the B3-state.
Change of Discharge Current in CO2 Plasma Induced by Q-switched CO2 Laser
Authors: Aoki Tadashi , Yamada Chikashi , Katayama Mikio
Published: November 2005

A change of discharge current is observed in CO2 plasma by irradiation with a Q-switched CO2 laser. It is elucidated that the increase of the discharge current just after the incidence of laser pulse is a correlated effect with an amplification mechanism of the laser pulse power. Evidence is also presented to support an interpretation that the rise and decay times of the current change produced by the laser pulse are effective measures of the relaxation times of the vibrational levels (10°0) and (00°1) of CO2 molecules in plasma. The effect of foreign gases is also examined.
Dielectric Constant and Conductivity Measurement of Powder Samples by the Cavity Perturbation Method
Authors: Kobayashi Hiroshi , Ogawa Seiya
Published: November 2005

The dielectric constant and conductivity of powder samples can be measured by a cavity perturbation method. A small amount of powder is placed at the point of maximum electric field intensity in a resonant cavity of T
E
103 mode at about 8935 MHz. Experimental data are analyzed by a theory which gives the complex conductivity of powders. The theory is based on the assumption that the quasistatic approximation is valid and there exists an equivalent powder depolarization factor. Coprecipitated Mn-Zn ferrite powder, 160 Å in diameter, is used as a powder sample. The observed dielectric constant and conductivity are in the range 8∼16 and 0.01∼0.02 \mho/cm, respectively. A Grounded n-Ge sample is also measured.
The theory and measuring technique developed herein are general and may be applicable to measurement of various powder samples.
Nucleation and Growth of Silver Films on Pure and Doped NaCl Substrates
Authors: Sharma S. K. , Bahl O. P.
Published: November 2005

Growth of silver films prepared onto pure and cobalt doped NaCl single crystal substrates cleaved in air and maintained at room temperature (∼25°C) under high vacuum (10-5 Torr) has been investigated in the initial stages. The stages has revealed wide differences in the growth behaviour of the films in the two cases. The density of nucleation on pure NaCl is found to be greater than that onto doped substrates. It is observed that the films grown on the doped substrates have (100) predominant orientation whereas the films grown onto pure substrates under identical conditions always showed polycrystalline structure.
Resistivity Behavior of Semiconducting YBaZrTiO3
Authors: Moratis C. J. , Bratton R. J.
Published: November 2005

The influence of Zr additions and oxygen pressure on the NTC and PTC characteristics of YBaTiO3 over the temperature range from -50° to +150°C was determined. The NTC behavior of doped YBaTiO3 depended upon the effect of the Zr dopant on the crystallographic phase transitions. The room temperature resistivity and the switching temperature were controlled by the dopant level and the prevailing oxygen pressure during cooling from the sintering temperature. Temperature coefficients of resistance ranged from -2 to -16%/°C in the NTC region and from +2 to +17%/°C in the PTC region.
Local Crystallization of Thermal Oxide Film of Silicon
Authors: Nagasima Naoyuki , Enari Hideo
Published: November 2005

The occurrence of crystallites in thermal oxide films of silicon is studied in connection with contamination by sodium and with surface irregularities on silicon, using reflecting electron diffraction technique. Crystallites formed under the presence of sodium are identified as α- and β-cristobalite. When sodium of about 1015 atoms/cm2 is deposited on the silicon surface before oxidation, the crystallites of a size discernible even by the naked eye are formed in the oxide films at 1100°C. The area of the crystallized region in the oxide film is proportional to the amount of sodium on the silicon surface before oxidation.
When a lapped or sand-blasted silicon wafer is oxidized, the grown oxide film is noncrystalline, as well as the chemically etched and mechanically polished wafers.
Temperature Dependence of Critical Current in Nb3Sn Ribbon
Authors: Matsunaga Sakuro , Ueda Kazuo
Published: November 2005

The temperature dependence of critical current in vapor-deposited Nb3Sn ribbon is measured in the temperature region above 4.2°K in magnetic fields below 55 kOe. The results of experiments are analysed by the Coffey's model. For the magnetic field of 30 kOe, the experimental values in the temperature region from 4.2°K to about 12°K agree with those calculated by the Coffey's model, but in the region above 12°K the experimental values become smaller than the calculated values. The temperature at which the experimental values deviate from the calculated values decreases with increasing magnetic field. This temperature is about 8°K in the magnetic field of 55 kOe.
Resistivity Anomaly in Semiconducting BaTiO3
Authors: Brahmecha B. G. , Sinha K. P.
Published: November 2005

The phenomenon of positive temperature coefficient of resistivity (PTCR) anomaly has been reexamined in BaTiO3 with dopings Er and Tb, whose compositions can be expressed by the formulae: Ba1-xErxTiO3 and Ba1-xTbxTiO3. The effect of partial substitution of Ba2+ ion by Sr2+ and Ca2+ on the Curie point is also observed. The composition ranges examined were confined to the region of semiconductivity. Formation of single phase solid solution was checked by an X-ray analysis, using powder photograph method.
A theoretical analysis of resistivity anomaly has been given by proposing a new mechanism based on the idea of scattering of an electron by spatial polarization fluctuations. It is found that PTCR anomaly is closely associated with the appearance and disappearance of dipole ordering in ferroelectric systems.
Determination of Depth Distribution of X-Rays in Matter
Authors: Fang P. H.
Published: November 2005

The problem of the uncertainty in the determination of the depth distribution of characteristic X-rays in microprobe target is discussed. A principle to choose the representation of the distribution function of the depth is proposed and a method to construct this function is formulated.
Origin of Memory Effect in Cu-Al-Ni Alloy
Authors: Otsuka Kazuhiro
Published: November 2005

The origin of the memory effect in Cu–14.2Al–4.3Ni (W/O) alloy has been investigated using the techniques of optical microscopy and electron microscopy. As a result the following have been established. The plastic deformation is caused by the growth or creation, and the contraction or disappearance of twins inside martensites, and the growth or contraction of martensites in the β1 phase region. Upon heating martensites transform back into the β1 phase and twins are annihilated, whether or not the martensite and twins have been introduced by deformation. These facts explain the origin of the memory effect.
Based on these observations, the requirements for the memory effect have been proposed as follows:
i) The martensite transformation is thermoelastic.
ii) The lattice invariant strains are not dislocations but twins.
The correlation between these requirements and the structural properties, and the reason why twins are annihilated upon the reverse transformation is also discussed.
Deformation of Single Crystal Wafers of Silicon Caused by Lapping
Authors: Yamagishi Sokichi
Published: November 2005

Two types of deformation of single crystal wafers of silicon introduced by lapping one face of a wafer are observed. There exists a critical thickness, T

c
, above which the deformation is symmetric with respect to the center of wafers (spherical deformation), and below which the deformation is symmetric with respect to a certain diameter (cylindrical deformation). The plots of the deflection for the spherical deformation at any cross section and for the cylindrical deformation at cross section perpendicular to axis of symmetry coincide with parabolic lines. In the case of {100} wafers, there are two stable modes for the cylindrical deformation and the axes of symmetry coincide with <100> on {100}. Whereas {111} wafers have a single stable mode: some axes of symmetry coincide with <211> and/or <110> but the rest does not coincide with any direction having low indices. It is likely that both types of deformation originate from the plastically deformed layer on the lapped face and that large portion of a wafer is deformed elastically except for the layer.
Sticking Coefficients of Gold Atoms in the Nucleation and Growth Process of Gold Deposits on Polyfluoroethylene-propylene
Authors: Murakami Yoshio
Published: November 2005

The sticking coefficients of gold on PFEP (polyfluoroethylene-propylene) were measured by using a microbalance, and were found to be extremely low as compared with those on other materials, such as alkali halide crystals and glasses. When the substrate temperature of PFEP is higher than 100°C, the coefficients never attain unity even at a thickness of several thousand angstroms.
From the transmission electron micrographs of the gold deposits and the variation of electrical resistivity with average deposit thickness, it appears that under limited conditions, preferential nucleation occurs on a limited number of active sites on PFEP, and the initial nuclei grow into small particles (islands) in the early stage of deposition. Each island then grows toward the direction of incidence of atoms by receiving the impinging atoms from the surrounding space. The resulting gold islands are mostly isolated until they grow up to several ten angstroms in height.
Use of a Toroidal Mirror in the Soft X-Ray Optical System
Authors: Ishii Takehiko , Aita Osamu , Ichikawa Kouichi , Sagawa Takasi
Published: November 2005

A toroidal mirror has been produced and used as a prereflector in the optical system of the soft X-ray spectroscopy. The mirror reduces the astigmatism inherent in a grazing-incidence monochromator and the intensity of radiation available for experiments is appreciably increased. Undesirable higher order radiation which appears in the first order spectrum is found to be efficiently removed when the mirror is used in the high energy spectral region. Critical cut-off wavelength in a few materials is discussed.