bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method of making an equivalent circuit for breaking arc
Authors: Kubono Takayoshi , Suzuki Hiroyuki 
Published: July 2007

AbstractThis paper considers breaking of the dc circuit by electrical contact and describes a method for measuring the voltage and current waveforms of the breaking arc and surge, as well as a method for deriving the arc equivalent circuit in the latter period of the breaking arc. The small inductance of the whole simulating circuit as well as the equivalent capacitance of the electrical contacts are determined so that the observed voltage waveform induced in the text circuit during the surge (i.e., the induced voltage waveform after chopping) and the voltage value in the resistor calculated in the simulating circuit agree.Next, the equivalent arc resistance, coherence, and the phase angle are calculated from the voltage and current waveforms of the breaking arc, which contain the high‐frequency components. Using the equivalent capacitance, equivalent arc resistance and phase angle, the arc equivalent circuit is estimated that can simulate the measured arc voltage and current waveforms. It is seen as a result that the arc equivalent circuit in the latter discharge period of the breaking arc can be represented as a series‐parallel circuit where resistor ra1 is connected to the parallel circuit (ra2/Ca) of resistor ra2 and the equivalent capacitance Ca. When, for example, the Ag electrical contact on a relay breaks the circuit of dc 36‐V and a noninductive resistor 3 ω, the arc equivalent circuit in the 105 ∼ 106 band in the latter period of the breaking arc is constructed by ra1 = 65 ω, ra2 = −68 ω, and Ca = 200 pF.
Numerical consideration and some improvement of corner diffraction formulas applicable to spherical wave incidence
Authors: Higa Yoshifumi , Uchikawa Kiyoshi , Inagaki Naoki , Kikuma Nobuyoshi 
Published: July 2007

AbstractDiffraction by a corner is one of the canonical problems remaining unsolved. However, several practical formulas have been proposed; any one of which must be able to be incorporated in the geometrical theory of diffraction (GTD). Of these, the corner diffraction formulas that can be applied to the spherical wave incidence are Burnside‐Pathak's formula (BP formula) and Zhang's formula (Z formula). In this paper, the BP formula and the Z formula are numerically compared by means of a hypothetical model consisting of a quarter infinite plane and an infinitesimal dipole. It is found that the BP formula and the Z formula become similar as long as they are not applied near the shadow boundary. The BP formula requires the edge parameters in the numerical process despite dealing with the corner diffraction. On the other hand, the Z formula needs only the parameters related to the corner. However, this formula experiences small discontinuity when the shadow boundary is traversed. In this paper, an empirical modification function is introduced into the Z formula so that a new corner diffraction formula (MZ formula) is proposed so that the diffracted field is uniform and continuous across the boundaries.
Fabrication of ferroelectric‐domain‐inverted gratings for LiNbO3 second harmonic generation devices by voltage application
Authors: Kintaka Kenji , Fujimura Masatoshi , Suhara Toshiaki , Nishihara Hiroshi 
Published: July 2007

AbstractTo realize a compact short‐wavelength coherent light source, development of an LiNbO3 waveguide quasi‐phase matched second harmonic generation devices is expected. To realize these devices, fabrication of the domain‐inverted grating is important. The authors discuss the fabrication of a grating with a period of about 3 μm near the surface of the z‐cut LiNbO3 crystal (with a thickness of 0.5 mm) by applying voltage. As the periodic electrode structure, the ladder electrode and the corrugation electrode were investigated. The distribution of the z component of the electric field induced under the periodic electrode was computed theoretically so that the structure of the periodic electrode effective for the grating fabrication was determined.From the experimental investigation, it was found that the domain inversion was more likely to occur on the +z side and the application of the current limited pulse voltage (∼ 10 kV, width of 1 ∼ 40 ms) was effective and that a domain‐inverted grating could be fabricated almost uniformly under the entire electrode if the current‐limiting value and the pulsewidth were adequate. When a ladder electrode (electrode linewidth/period ∼ 0.2) is used in vacuum and when a corrugation electrode was used in insulation oil, suitable structures can be fabricated for the device, which is uniform in the waveguide cross section and the inverted width to the uninverted width was close to one to one under the periodic electrode.
Propagation characteristics of the magnetostatic surface wave in the composite structure of yttrium‐iron garnet film and YBCO
Authors: Fukusako Takeshi , Tsutsumi Makoto 
Published: July 2007

AbstractThe propagation characteristics of the magnetostatic surface wave in a composite waveguide with a YIG film and YBCO were investigated theoretically and experimentally.First, using the equivalent complex permittivity of YBCO obtained by the two‐fluid model and the permeability tensor of a YIG film, the dispersion relationship of the waveguide was derived. It was proved theoretically that a strong nonreciprocity within the 2.4‐GHz bandwidth with low loss could be achieved by placing superconducting material in the waveguide. The influence of magnetic loss of YIG, ΔH, on the superconducting material also was discussed in detail and it was found that when ΔH exceeded 1 Oe, the effect on the loss reduction by YBCO disappeared.The propagation characteristic of the magnetostatic surface wave in the waveguide with superconducting material was evaluated experimentally at liquid nitrogen temperature. Through a comparison of this result with that obtained in a waveguide with copper, nonreciprocity was discussed. In addition, the delay characteristic of the waveguide with a composite structure of YIG‐YBCO was demonstrated experimentally.
Transient scattering responses from a plane interface between dielectric half‐spaces
Authors: Shirai Hiroshi 
Published: July 2007

AbstractThe transient scattered electromagnetic field due to an impulsive line source placed near the boundary between two dielectric media is formulated by the Cagniard‐de Hoop method. The scattered field is divided into the direct wave and the reflected wave. Then the reflected wave is divided further into the conventional reflected wave, and the head wave contribution appearing in the total reflection region. The rigorous solutions for each contribution are obtained. The wavefront approximation that can be used immediately after the wave arrival also is derived. The relationship between the wavefront approximation and the high‐frequency asymptotic geometrical optics field derived in the frequency domain is discussed.
Location and profile of phase conjugate image with gaussian beam pumping
Authors: Okamoto Atsushi , Mishima Teruhito , Sato Kunihiro , Sakuraba Ichiro 
Published: July 2007

AbstractWhen applying phase conjugate waves to various types of image processing, the characteristics of the wavefront, generated by the nonlinear optical medium, are an important research problem. The characteristics of a phase conjugate mirror with plane wave pumping have been investigated in previous research. To perform more realistic analysis, we derive equations describing the image location of the phase conjugate mirror with fundamental mode Gaussian beams as the pumping light and calculate the phase conjugate images numerically. The relationship between the probe light and the phase conjugate image using the Fresnel diffraction formula will be formulated first. Then the image location and the image magnification factor in consideration of the wave‐front curvature of the pump light is derived. Then the characteristics of the image location are analyzed considering the change of the curvature radius of the Gaussian beam in the thickness direction of the nonlinear optical medium. The image profile of the phase conjugate mirror is found by numerical calculation. The results show for the first time the effects of wavefront curvature of the pump light on the image reconstruction capability, which is an important characteristic of the phase conjugate mirror.
Nonradiative dielectric‐guide FM gunn oscillator at 60‐GHz band
Authors: Kuroki Futoshi , Baba Junnei , Furuya Hiroshi , Member Tsukasa Yoneyama 
Published: July 2007

AbstractA nonradiative dielectric (NRD)‐guide FM Gunn oscillator with a built‐in circulator has been developed for the 60‐GHz frequency band, which has attracted considerable attention recently in Japan. In the fabrication of the 60‐GHz band NRD‐guide Gunn oscillator, a Gunn diode sealed in a specially fabricated compact package 1.2 mm in diameter has been used instead of the large‐diameter Gunn diode package commercially available. The oscillator has an output power above 130 mW, which is sufficient for practical applications.An NRD‐guide circulator also is fabricated to protect the oscillator from reflected wave. Using NiZn ferrite material, much better performance is obtained compared to conventional microstripline circulators. A frequency modulator using a beam‐lead varactor diode has also been designed and fabricated. Emphasis has been placed on structural simplicity and modulation sensitivity. Based on all these, an FM Gunn oscillator is fabricated, and for a bias voltage of 15 V applied to the varactor diode, a frequency deviation of 260 MHz is obtained. This FM Gunn oscillator with built‐in circulator can be contained in a compact housing 3 cm × 3.5 cm.
Auger electron spectroscopy study of the solid‐phase reactions in Al3Zr/Zr/Si contact systems
Authors: Yanagisawa Hideto , Karasawa Hajime , Noya Atshshi , Sasaki Katsutaka 
Published: July 2007

AbstractTo obtain the fundamental understanding on the capability to apply the Zr film to Al metallization technology for Si‐LSI, interfacial solid‐phase reactions in Al/Zr/Si, Al‐Zr/Zr/Si, and Al3Zr/Zr/Si contact systems have been investigated by AES analysis. In the Al/Zr/Si system, Al and Zr layers reacted spontaneously and interdiffused each other even before the heat treatment. In the Al‐Zr/Zr/Si system, in which the Al overlayer was replaced with the Zr‐doped Al film, well‐separated interfaces of Al‐Zr/Zr and Zr/Si were observed before the heat treatment. But when heat treated at 400°C, Zr atoms in the Zr layer migrated into the Al‐Zr overlayer and the interposed Zr layer became too thin prior to the formation of the distinct Zr silicide layer. In the Al3Zr/Zr/Si system, the amorphous overlayer with the composition of Al3Zr recrystallized into a stable Al3Zr intermetallic compound during the heat treatment above 400°C. In this system, because the thermal equilibrium state is realized at the Al3Zr/Zr interface, a possible solid‐phase reaction is restricted only at the Zr/Si interface. Therefore, the system tolerates the temperatures up to 500°C and a stable Zr‐silicide layer can be formed at the Zr/Si interface.
Heat‐proof properties of Ta2N anodized thin‐film capacitors prepared at low anodization voltage
Authors: Sasaki Katsutaka , Yamane Misao , Abe Yoshio , Noya Atsushi 
Published: July 2007

AbstractTo clarify how the high heat‐proof properties of Ta2N anodized film capacitors are maintained when the film thickness is reduced, the effects of heat treatment temperature increase on dissipation factor (tan δ), temperature coefficient of capacitance and dc leakage current are studied for a capacitor formed by reducing the anodization voltage. The results will follow. Even for the anodized capacitor prepared at a reduced anodization voltage of 80 V, there is no thermal degradation in tan δ and temperature coefficient of capacitance for the heat treatment below 400°C. The leakage current also shows a qualitatively similar behavior for a reduced anodization voltage with no change in the electrical conduction mechanism, even when the anodization voltage is reduced. On the other hand, while the leakage current of this Ta2N anodized film formed at 80 V changes little up to a heat‐treatment temperature of 300°C, it increases rapidly at 350°C. However, compared to a Ta anodized film formed at 160 V anodization voltage with the same capacitance, this Ta2N anodized film formed at 80 V has a drastically improved heat resistance in terms of tan δ, temperature coefficient of capacitance and leakage current. From these results, it has been clarified that the use of Ta2N compound is an extremely effective way to maintain heat resistance while reducing the film thickness.
Novel two‐mode cutoff‐waveguide filters and their new design method
Authors: Iguchi Kazutaka , Tsuji Mikio , Members Hiroshi Shigesawa 
Published: July 2007

AbstractThis paper describes a new method of configuration of a cutoff waveguide filter with attenuation poles. When a filter with attenuation poles is constructed, often the degenerate mode is used or the filter configuration uses two paths. In this paper, a new configuration is presented in which the negative coupling between the TE101and TE201modes in a waveguide cavity is used. The test fabrication and experiment are carried out for both the cavity resonator loading and the dielectric resonator loading. The effectiveness of the present filter configuration and the design method is confirmed.
Optical design for large‐scale free‐space optical switching modules
Authors: Shirai Seiiti , Serikawa Tadashi 
Published: July 2007

AbstractTo achieve large‐scale and compact free‐space optical switching networks, highly efficient coupling between input and output fiber arrays and low‐loss beam propagation for a long‐span are required. In the cascaded optical beam‐shifter module using liquid‐crystal devices, beam expansion due to optical diffraction limits the scale of the switching network.A microlens configuration consisting of collimating lenses and relay lenses with a long focal length is proposed for long‐span beam propagation. This lens configuration can reduce the limitation on the scale of switching network. It is shown that a large‐scale and compact optical switching network can be constructed. The relationship between the aperture size to determine the physical size of an optical switch and the focal lengths for the required lens system also are shown. A long focal‐length microlens fabricated using the sputter‐liftoff method was shown to be very useful for long‐span beam propagation.
A study on degradation of spatial resolution in frequency‐modulated continuous wave reflectometry due to nonlinear optical frequency sweep
Authors: Wang Lu‐Tang , Liyama Koichi , Hayashi Ken‐Ichi 
Published: July 2007

AbstractThe degradation of the spatial resolution in frequency‐modulated continuous wave (FMCW) reflec‐tometry due to the nonlinearity in the optical frequency sweep are discussed both experimentally and theoretically. The response lag in the optical frequency change of a laser diode behind the injection current change was experimentally measured, showing that there were several time constants in the optical frequency response. The interference signals in the FMCW reflectometry were theoretically calculated by taking account of the response lag. From these calculations, the beat frequency becomes low just after the turning point of the optical frequency sweep; this is due to the response lag in the optical frequency response. As a result, the spectrum of the interference signal is spread out toward the low frequency region and spatial resolution is degraded. Moreover, the spatial resolution is seriously degraded with increasing the diagnosing distance due to the nonlinearity in the optical frequency sweep. The calculated results agree well with the measured results.
Kinetic study of WSix‐CVD processes—a comparison of WF6/SiH4 and WF6/Si2H6 reaction systems
Authors: Saito Takeyasu , Shimogaki Yukihiro , Egashira Yasuyuki , Komiyama Hiroshi , Sugawara Katsuro , Takahiro Katsumi , Nagata Shinji , Yamaguchi Sadae 
Published: July 2007

AbstractKinetic study on chemical vapor deposition of tungsten silicide (CVD‐WSix) by the mixture of WF6/SiH4 or WF6/Si2H6 was made using an externally heated tubular reactor. By investigating the effect of the film precipitation area on the gas phase volume ratio (the S/V ratio) in film formation, it can be concluded that the initial step of film precipitation was dominated by radical chain reaction. In addition, a new process to form WSix using preliminary excitation of gas phase reaction at the inlet of the reactor was proposed. Using this process, film composition was controlled and the formation of WSi2.5 films with excellent step coverage was realized.
Copper self‐sputtering and filling of submicron holes
Authors: Asamaki Tatsuo , Miura Tsutomu 
Published: July 2007

AbstractA new thin‐film technology using self‐sputtering, which sputters the target with its own ions only, not with inert gas ions, is investigated. In the present paper, the characteristics of self‐sputtering and filling of deep holes with metal are investigated. Self‐sputtering of copper is performed in a wide pressure range of 10−2 Pa to 10−4 Pa. A high target current of 7 A to 10 A for a 4‐inch planar magnetron target is essential for a self‐sputtering process that yields a very high deposition rate of about 4 μm/min at 60 mm from the target surface. Conditions for sustained self‐sputtering are determined.Good bottom coverage of 100 percent is obtained in thinner film deposition (0.2 μm thick) and 50 percent coverage is obtained in thicker thin‐film deposition (1.2 μm thick); the submicron holes have a high aspect ratio of 2, an inlet diameter of 0.6 μm, and a depth of 1.2 μm. It is found that the bottom coverage β increases sharply when the ratio α = (distance between target and substrate)/(radius of erosion center ring) is larger than 2 and although at lower pressure the bottom coverage by self‐sputter deposition saturates at longer distances, the bottom coverage in conventional sputter deposition at 3 × 10−1 Pa decreases with distance after saturation. The bottom coverage β also decreases with increasing pressure, with the thickness of the deposited film and with the radial distance of the substrate position from the target center toward the erosion center.
Control of radical species in microwave plasma chemical vapor deposition
Authors: Kato Isamu , Yoneda Toshiyuki , Matsushita Toru , Yamashita Makoto 
Published: July 2007

AbstractThe spatial distributions of electron temperature and density in pure Ar plasma in a double‐tubed coaxial‐line type microwave plasma chemical vapor deposition (CVD) system were measured using the probe method. It was found that the electron temperature and electron density dropped sharply in an area 4 cm from the edge of the discharge tube and they decreased slowly in an area farther away from the forementioned area. SiH4 gas was dissociated in Ar plasma, and the electron temperature and density of the plasma were varied by changing the location of the SiH4 gas inlet. As a result, it was found that the fragmentation pattern of radical species could be varied by changing the location of the SiH4 gas inlet.In addition, films were fabricated under various fragmentation patterns and the qualities of these films were evaluated. It was found that the film quality could be improved by dissociating SiH4 gas at low electron temperature.
Discoloration on color cathode ray tube and its correction system using L‐shaped magnetic material
Authors: Nasuno Hiroshi , Haga Akira 
Published: July 2007

AbstractColor cathode ray tubes (CRTs) have been used as display devices for television sets and computers. Color CRTs contain a shadow mask to select electron beams for a particular color. The shadow mask is made of very thin (0.1 to 0.25 mm) iron and is easily magnetized. When the shadow mask is magnetized, the magnetic field profile in the CRT is modified, causing discoloration due to the deviation of electron beam trajectory.To investigate the influence of the magnetization of the shadow mask on the electron trajectory, the magnetic characteristics of the shadow mask and its holder and magnetic field profile in the color CRT were analyzed using three‐dimensional magnetic field analysis. In addition, the influence of the magnetized shadow mask on the electron beam trajectory was calculated to find the quantity of mislanding. In this paper, the magnetic field control method by placing L‐shaped magnetic materials is proposed and it was proved experimentally that the correction of color discoloration can be achieved by this method.
Response of a dielectric sphere for electromagnetic pulsed wave—cases of back‐ and forward‐scattering
Authors: Itoh Akira , Hosono Toshio 
Published: July 2007

AbstractIt is important to analyze the scattering phenomena of a dielectric sphere in conjunction with the improvement of performance of weather radar to observe rain clouds. This paper considers the transient scattering phenomena when a plane electromagnetic pulse wave is incident on a dielectric sphere. Specifically, the responses of the back‐ and forward‐scattering observed at distant points are presented. The response waveforms are compared when the permittivity, loss, and incident waveform are varied. Analyzing the typical response waveforms, the propagation paths were estimated from the characteristics of the response time and waveform so that the scattering phenomena were studied. The fast inversion of Laplace transform (FILT) method was used for the calculation of the transient responses.
High‐power polymer optical fiber amplifier
Authors: Yamamoto Tsuyoshi , Fujii Kazuhito , Tagaya Akihiro , Teramoto Shigehiro , Nihei Eisuke , Koike Yasuhiro , Sasaki Keisuke 
Published: July 2007

AbstractOrganic dye‐doped polymer optical fiber amplifiers (POFA) are fabricated and their amplification characteristics are investigated. Rhodamine 6G, Rhodamine B, and Perylene Red are used as organic dyes for optical amplification. The amplification of optical signals at 571 nm, 591 nm, and 621 nm wavelengths is confirmed through pumping by the second harmonic of a pulse‐operated Nd: YAG laser. It is shown that very high output powers can be achieved by increasing the caliber of Rhodamine B doped POFA. One‐kW optical signal output (30 dB gain) is obtainable at dye doping of 1 ppm, 500‐μm core radius, and POFA length of 250 mm. The conversion efficiency of such a high output amplifier is 27 percent. The POFAs are advantageous over liquid‐dye lasers because they are easily handled. Multistage POFAs in the form of joint POFAs are proposed as new light source systems and their oscillation characteristics are discussed.
High‐power ALGaAs single‐stripe laser diode with window‐grown‐on‐facets
Authors: Matsumoto Mitsuhiro , Sasaki Kazuaki , Kondo Masaki , Takeoka Tadashi , Yamamoto Saburo , Ishizumi Takashi 
Published: July 2007

AbstractA high‐power single‐stripe AlGaAs laser diode capable of reliable operation at an output power greater than 50 mW is useful for improvement in optical data storage systems and second harmonic generation elements. A novel window structure laser diode is developed and referred to as a window‐grown‐on‐facets (WGF) laser. Highly reliable operation is attained under 10 mW at 50°C beyond 10, 000 hours in the wavelength of 830 nm and under 70 mW at 60°C beyond 4000 hours in the wavelength of 780 nm, respectively. In the WGF laser, the window effects are found only in the case of the Al content of the window layer greater than that of the cladding layer. To explain the experimental results, calculation of carrier leakage from the active layer to the window layer is performed. The reduction of the window effects is caused by the carrier leakage.