bluuebunny/crossref_metadata_2025_split huggingface dataset:
Finite—element solution of three—dimensional resonator problems. Novel tetrahedral element
Authors: Hano Mitsuo 
Published: July 2007

AbstractA new tetrahedral element is proposed for the finite element analysis of a three‐dimensional resonator problem. It has been reported that in finite element analysis with the conventional tetrahedral elements, nonphysical spurious solutions are generated. In the tetrahedral element proposed here, only the components of electric or magnetic field along the element surface are used as unknown parameters. It is shown that there are many zero eigenvalues in the finite element expression obtained by the new tetrahedral elements. It is demonstrated that the matrix in the new method can be regularized with the eigenvectors corresponding to the zero eigenvalues so that a substantial reduction of the unknown parameters can be realized. The regularization process is purely mathematical. No eigenvalues and eigenvectors are altered. From the eigenvalues obtained from actual numerical calculations for a resonator, it is shown that several of the smaller ones correspond to the resonant modes, and no spurious solutions appear. A feature of the present method is that the spurious modes can be eliminated and the number of unknown parameters is reduced substantially. The method is expected to be an effective analysis method for finite element solutions of three‐dimensional resonator problems.
Phase—synchronous–type walsh analyzer using switched—capacitor circuit
Authors: Sasaki Itsuo , Yoneda Shojiro , Kasai Tamotsu 
Published: July 2007

AbstractThe Walsh transformation is a useful method which can replace the Fourier transformation for analysis of alternating‐numbers, and is suitable for digital waveform analyses. Since this is a binary transformation, its hardware realization is achieved easily. Using this advantage, this paper proposes a discrete Walsh‐transformation circuit using a switched‐capacitor circuit. This paper also proposes a solution of a problem of the change of power spectrum due to the phase‐shift of the input signal which prevents practical applications of the Walsh transformation to an electronic circuit. In the proposed circuit, a Walsh‐function wave based on a rectangular waveform synchronized with the input signal is formed, and this is used for the clock of the switched‐capacitor discrete Walsh‐transformation circuit. This arrangement makes the signal‐detection period variable so that the signal is always processed with no phase shift. This arrangement itself is also suitable for a switched‐capacitor circuit. A prototype switched‐capacitor discrete Walsh‐transformation circuit (for 32 sampling points) was made with discrete components. The results confirm that the proposed method is effective for analyzing rectangular waves.
Formation of (Hf·Ti)C film on cemented carbide tools by low—pressure chemical vapor deposition
Authors: Fuyama Moriaki , Hanazono Masanobu , Ura Mitsuru , Honda Haruhiko 
Published: July 2007

AbstractThe optimum deposition conditions of (Hf·Ti)C film on cemented carbide tools using low‐pressure chemical vapor deposition are discussed here based on evaluations of the physical and mechanical properties of the deposited films.The film composition could be controlled through the flow rate of titanium and hafnium iodides and the film formed had a Vicker's hardness of 2500 to 3000 kg/mm2. The wear resistance of the (Hf·Ti)C coated tool was as high as that of the previously developed HfC coated tool. The grooving wear of the (Hf·Ti)C coated tool was higher than that of the TiC coated tool. This was attributed to the larger thermal expansion coefficient of the (Hf·Ti)C film compared with those of TiC and HfC.
Fiber misalignment measurement method using one—directionally observed image
Authors: Ide Atsushi , Tachikura Masao 
Published: July 2007

AbstractThis paper investigates the measurement method of optical fiber offset in two directions by one‐directionally observed image. This method employs the transmitted illumination and the bright lines of the intensity distribution due to the lens effect of the fiber are used to observe the position. The method is advantageous because of a simple mechanism for its realization. The observation principle of fiber position is investigated based on computer simulation and experimental results to clarify characteristics of the method. The real measurement of the fiber offset and its precision is investigated for fusion mass‐splicing, to which the present method is very suitable. Employing this method, the standard deviation of 1.3 μm is achieved in precision of the measurements of the fiber offset. The screening characteristics for a given offset are also evaluated.
Design method of general‐purpose and high—speed digital correlator LSI
Authors: Morikura Masahiro , Enomoto Kiyoshi , Kato Shuzo 
Published: July 2007

AbstractThis paper proposes a construction of a general‐purpose high‐speed correlator LSI, aiming at applications to various problems such as digital signal processing and synchronization word detection. A general method of constructing the rearrangement circuit as well as the generation of a highspeed detection pulse are presented, and are. important in the construction of a highspeed synchronization word detector, one of the major applications of the high‐speed digital correlator. It was shown by experiment that the developed general‐purpose high‐speed digital correlator has the feature that the parameters can be set in a flexible way according to the problem, and can operate up to 200 MHz by the one—chip structure (two‐parallel processing).
Biopolar—voltage–controlled optical switch fabricated on Z—cut Ti:LiNbO3 intersecting waveguides
Authors: Nakajima Hirochika , Sawaki Ippei , Seino Minoru , Yamane Takashi 
Published: July 2007

AbstractA new optical switch is proposed in which attention is paid to the behavior of the guided wave at the crossing of an intersecting waveguide. Design and fabrication of an optimal configuration were carried out at a practical wavelength of 1.3 μm. For the analysis of the operating mechanism and the optimum design, a waveguide analysis method based on the Fourier transform developed originally has been used. By means of the electrodes formed via a buffer layer on a Z‐cut Ti:LiNbO3, a bipolar optical switch was fabricated in which switching is possible in both the positive and negative polarities. This switch has a low loss and low crosstalk if the intersection length is short, although the operating voltage is high. If the device length is increased for reduction of the operating voltage, other characteristics are degraded. Therefore, it is necessary to diffuse the double Ti layers below the electrodes and to improve the electrode structure. In the device with an intersection length of 8 mm thus obtained, the operating voltage of 14 V was realized. By way of theory and experiment, the characteristics of this switch were understood and the guideline for the future applications was obtained.
OEIC photoreceiver using InP system with a 5–V source voltage supply
Authors: Tojo Masaaki , Matsuda Kenichi , Kubo Minoru , Sibata Jun 
Published: July 2007

AbstractA PIN/JFET using an InP‐based material for receiving an optical signal at a wavelength of 1 μm has been developed. From a practical viewpoint, operation using a single power supply is desirable. In this study, an opto‐electric integrated circuit (OEIC) composed of a PIN/PD, JFET, feedback resistor, etc., was fabricated on a semi‐insulating substrate and then the characteristics of each component were evaluated. The pinchoff voltage and cutoff frequency of the JFET were 1.2 V and 900 MHz, respectively. The transimpedance in operation was 965 ft, which was almost the same as the feedback resistance. When the power supply voltage was 5 V, the 3‐dB cutoff frequency was 220 MHz, indicating that operation using a single power supply is feasible. The 1/f noise of JFET was 20 nV √Hz and the receiver sensitivity was −24.1 dBm. High reliability could be ensured by employing a 50‐hr THB screening test.
Optogalvanic effect on a hollow cathode He—Cd+ laser
Authors: Fuke Akira , Masuda Katsuhiko , Tokita Yasuhiro 
Published: July 2007

AbstractA hollow cathode He—Cd+ laser simultaneously emits three primary colors. Therefore, a white color laser beam is emitted from this laser. This paper describes the optogalvanic effect and the results of our measurements under the study of stabilization of the white light laser. In the measurement, the colors red, green or blue were monochromatically emitted and the change of the anode voltage was measured in accordance with laser optical power by turning the optical path in the resonator on and off. The optogalvanic signal was noticeable when the color red or blue was emitted. However, almost no effect was observed during emission of the color green. The optogalvanic signal during emission of the color blue depends not only on the optical intensity, but the beam diameter. This indicates that the optogalvanic signal during emission of the color blue is dependent on the change of the cathodic effect. On the other hand, the gain distribution of blue in the bore is presumed to reach the neighborhood of the cathode surface. During emission of red, the optogalvanic signal is proportional to the light intensity, regardless of the beam diameter. It is understood that the optogalvanic effect during red color emission is caused by the change of the He+ population which is distributed at the center of the bore and is the origin of the red color emission.
Amorphous—silicon thin—film transistors and their integrated circuits
Authors: Uchida Yasutaka , Oda Shunri , Matsumura Masakiyo 
Published: July 2007

AbstractSince the technology to integrate amorphous‐silicon thin‐film transistors on a large area glass substrate is a key to realizing a flat panel display with high capacity, high resolution, and full color, it has been developed extensively in industry research organizations worldwide. Attempts have also been made to apply them for sensing devices and printing devices. The amorphous‐silicon thin‐film transistor is becoming central to man‐machine interface devices, and the improvement of its performance has become important. This paper introduces these technological trends with emphasis on our own research results.
Relationship between the contact resistance and the temperature near electrical contacts switching continually
Authors: Kubono Takayoshi , Teraoka Shinji 
Published: July 2007

AbstractThe temperature increase of electrical rays is regulated by the electrical component regulatory law. There are few examples of measurement of temperature characteristics during the multiple open and close operations at the electrical contact of a small relay. In this paper, the resistive load circuit of dc 30 V to 10 A was open for 2 s and closed for 1 sa total of 100,000 times. During each closing period, the contact resistance, the temperature near the electrical contact, the temperature of the interior wall of the relay case, and room temperature were measured and correlated. The temperature near the electrical contact depends strongly on the contact resistance and increases or decreases with several cycles of delay in the open and close cycle for the increase and decrease of the contact resistance. The contact resistance for 1000 continuous measurements and the average of the temperature increase (difference between the temperature near the electrical contact and the room temperature) are proportional to the correlation factor of more than 0.95. When the temperature increases between the contacts with and without through‐holes are compared, it is seen that the increase due to thermal radiation was smaller at the through‐hole when the contact with through‐holes is used. From these experimental results, the typical temperature characteristics of the electrical contact as a principal functional device were clarified.
Spatial resolution in NMR fresnel transform imaging
Authors: Yamada Yoshifumi , Hayashi Takehiko , Tanaka Kunio , Abe Zenmonn 
Published: July 2007

AbstractThere have been no reports of papers which studied thoroughly and quantitatively the relation between the spatial resolution and the imaging parameters in the Fresnel transform technique. This paper describes the relation between the spatial resolution and the imaging parameters in the Fresnel transform technique. The experimental results are shown to be in good agreement with the theoretical estimations. Moreover, the theoretical consideration shows that a localized imaging is possible without using any localization technique if the scanning of the characteristic field is limited to a local region. An experimental result on the local imaging is presented. The results obtained in this paper show that the Fresnel transform technique has a great promise as a new NMR imaging method.
Copper‐polyimide interaction during imidization process of polyamic acid solution to polyimide
Authors: Miura Osamu , Miyazaki Kunio , Numata Shunichi , Watanabe Hiroshi 
Published: July 2007

AbstractA polyimide film cured on a copper wire was found to contain a large amount of Cu. The cause of the Cu contamination was investigated. As a result of the investigation, it was confirmed that Cu is ionized by the carboxyl group which is bonded to the benzene ring in polyamic acid and is dissolved into the varnish. When Cu which is dissolved into varnish, partially oxidized during heating at 300°C, it precipitates in a polyimide film and forms an aggregated body.
Analysis of the waveguide with loss or gain by the finite‐element method
Authors: Matsuhara Masanori , Angkaew Tuptim 
Published: July 2007

AbstractIn the past the finite‐element method with a variational formulation has been used for numerical analyses of the propagation characteristics of electromagnetic waveguides. However, this method based on the variational representation is not applicable to waveguides with losses or gains.This paper derives a generalized Galerkin equation which is established for waveguides with losses or gains. The finite‐element method is proposed based on this Galerkin equation. As examples of numerical calculations, a waveguide loaded with a lossy dielectric, a helical waveguide and a microstrip line were analyzed.
Finite‐element solution of three‐dimensional periodic waveguide problems
Authors: Inoue Kazuhiro , Hayata Kazuya , Koshiba Masanori 
Published: July 2007

AbstractWith a view to developing a method enabling derivation of the propagation characteristics of a three‐dimensional (3‐D) periodic waveguide with an arbitrary shape, an analysis technique based on the finite‐element method with tetrahedral elements is proposed and its formulation developed. For the finite‐element analysis of the electromagnetic field in a 3‐D inhomogeneous region including a dielectric material, the variational expression in terms of three components of magnetic field is convenient. However, if the conventional variational expression is used directly for solving eigenvalue problems, spurious solutions can appear. In this paper, to suppress and eliminate these spurious solutions, various countermeasures to spurious solutions, developed for the finite‐element analysis of a waveguide uniform in the propagation direction that can equivalently be treated as a 2‐D problem. These include: the penalty function method, the transverse magnetic‐field component method and the reduction method, all of which are extended to the finite‐element analysis of 3‐D periodic waveguide problems. Specifically, by way of the numerical examples for a rectangular waveguide loaded with dielectric material with a periodic structure, the validity of the proposed method and the adaptability of each method for suppressing and eliminating spurious solutions are investigated.
High‐frequency monolithic differential input/output integrator
Authors: Takagi Shigetaka , Fujii Nobuo , Yanagisawa Takeshi 
Published: July 2007

AbstractThe high‐frequency monolithic integrator proposed by the authors in [1] has excellent frequency characteristics because it does not require pnp transistors which have poor high frequency characteristics. In addition, since the time constant can be changed electronically, it is also suited as an active element for monolithic automatic tuning filter using a PLL. However, since this integrator is a balanced‐type one, a circuit converting the signals from the unbalanced type to the balanced type is needed. Therefore, the chip area and power consumption will increase.This paper points out that the integrator using the balanced negative impedance converter (NIC) proposed in [1] can be used as the differential input/output integrator for an unbalanced input since the circuit is superior in the common mode rejection ratio. Also, the method for varying the time constant is improved and the circuit is simplified so that the frequency characteristics are improved further. Problems on the reduction in the variation range of the time constant and on the variation of the dc potentials are relaxed by the appropriate determination of element values, and the circuit technique, respectively. The proposed integrator is made as a monolithic integrated circuit by the 3‐μm bipolar process. Experiments of a third‐order low‐pass filter with the cutoff frequency of MHz are carried out to confirm the practicality and effectiveness of the proposed integrator.
Study of BiCMOS cache memory
Authors: Kurita Kozaburo , Hotta Takashi , Maejima Hideo , Hotta Atsuo 
Published: July 2007

AbstractTo improve the speed of the processors for CPU of minicomputers and other systems, it is required to improve the machine cycle and the memory cycle, which are the performance indexes of the system. The general idea to realize a high‐speed memory cycle is to apply the cache memory, which provides a hierarchical structure for the memory. This paper considers the realization of the cache memory by Hi‐BiCMOS (high‐performance bipolar CMOS) technology, which aims at a high‐speed, highly integrated LSI by combining the microstructured CMOS and high‐speed bipolar devices at the element level of the circuits. As the basic circuit, a RAM‐combined Hi‐BiCMOS circuit comparator is proposed, where the comparator logic is introduced into the sense amplifier of RAM. Applying the proposed circuit, TLB (Translation Lookaside Buffer) is designed and constructed, which performs the address transformation by cache memory. A satisfactory operation of the circuit was verified with the address conversion time of 13.3 ns. An evaluation by simulation was made for applying the proposed circuit to a 4K Byte cache memory, and it is indicated that the cache access through an address conversion can be made in 17.5 ns.
Three‐dimensional electromagnetic analysis of a vacuum window involving waveguides
Authors: Nakatsuka Hirotaka , Yoshida Norinobu , Fukai Ichiro 
Published: July 2007

AbstractLocal heating of the pillbox‐type vacuum window employed in microwave heating of nuclear fusion apparatus TOKAMAK has been a problem when used under a high power, particularly under the ghost mode. This factor is used to determine the maximum power of the heating system. However, in the measurement in actual operation, only the electric field can be measured when the amplitude and reflection coefficient become small due to the loss. An analysis taking into consideration the dielectric loss is needed to determine the characteristics of the electromagnetic field distribution in the ghost mode. We have applied the spatial network method to the pillbox vacuum window excited by a rectangular waveguide. The method has a number of unique features as a time domain analysis method for three‐dimensional electromagnetic fields. After the basic treatment is described, the electromagnetic field of the ghost mode is simulated by the analysis taking into consideration the dielectric loss. The effectiveness of the three‐dimensional electromagnetic analysis for the entire system is presented.
All‐NbN nanobridges for DC‐SQUID application produced by field emission
Authors: Nagaoka Shiro , Hamasaki Katsuyoshi , Irie Akinobu , Yamashita Tsutomu , Kougo Masanori 
Published: July 2007

AbstractThis paper describes the method for producing a nanobridge‐type SQUID, the LsIo/ϕOratio of which can be regulated to an optimal value at the liquid He temperature (4.2 K), and the properties of the SQUID. An epitaxial NbN film is produced by the reactive RF magnetron sputtering method for use as the electrode material, and an MgO film, which is thermally stable, is used as the insulating barrier. The Josephson nanobridges are formed in MgO film of the NbN/MgO (5‐10 nm)/NbN junction of about 4 × 4 μm2in area by field emission in the liquid He environment. The junction resistance before the application of electric field is very high, that is, 1 MΩ or higher. Needless to say, Josephson current is absent in the junction. The critical current can easily be regulated to a desired value by varying the applied voltage. The produced SQUID exhibits a high stability to the heat cycle test (300 K‐4.2 K) which is carried out 50 to 60 times for about 2 years.
Analysis of microstrip‐magnetostatic wave resonators
Authors: Tsutsumi Makoto , Takeda Tomoyuki 
Published: July 2007

AbstractThis paper analyzes a microstrip‐type magnetostatic wave resonator made of a YIG film loaded with a metal disk. First, based on a simple model consisting of a magnetic wall at the edge of the disk, the relationship between the resonant frequency and the aspect ratio and the Q value was investigated. Next, a more realistic model is set up and analyzed by the mode matching technique. The relationship between various resonator parameters and the energy trapping situation of the magnetostatic wave in the disk is found. Also the distribution of the RF magnetization in the disk is presented.
Fiber‐optic phase modulator using piezoelectric copolymer coating
Authors: Imai Masaaki , Odajima Akira 
Published: July 2007

AbstractAn optical fiber was coated with vinylidene fluoride/trifluoroethylene piezoelectric copolymer (P(VDFx/TRFE100‐x), x = 73 mole%) to a thickness of 85‐100 μm via extrusion method. To create peizoelectricity, this fiber was processed to have polarization in the radial direction by corona discharge poling and was used to construct a fiber phase modulator; ac/dc voltages were applied to concentric cylindrical electrodes attached to the optical fiber and phase shifts were investigated in relation to the applied electric field. The wavelength characteristics of phase modulation sensitivity were measured in a wide range of 20 Hz to 50 MHz. The phase modulation sensitivities were 2.1 × 10−5 rad/(V/m)/fiber length (m) in the low‐frequency range and 3.5 × 10−6 rad/(V/m)/m in the high‐frequency range. At frequencies higher than 1 MHz, resonances in the fiber‐jacket composite were observed clearly. Next, to explain the phase modulation characteristics, the theoretical investigation of a two‐layer model from silica glass and piezoelectric copolymer coating was carried out.
Full vectorial finite‐element formulation for anisotropic waveguides with complex permittivity tensor
Authors: Hayata Kazuya , Miura Kazunori , Koshiba Masanori 
Published: July 2007

AbstractAn efficient computer‐aided solution method based on the vectorial finite‐element method is developed for solving arbitrary waveguiding structures containing anisotropic materials with complex permittivity tensor. In this scheme, a formulation in terms of the transverse magnetic field component is adopted and the eigenvalue of the final matrix equation corresponds to the propagation constant itself. Thus one can avoid unnecessary iterations which arise when using complex frequencies. To demonstrate the strength of the present method, numerical results are shown for a rectangular waveguide filled with a lossy anisotropic dielectric with off‐diagonal elements in a permittivity tensor.