bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coaxial‐line type microwave plasma CVD system to fabricate SiN films
Authors: Kato Isamu , Kohyama Yusuke , Noguchi Kazuto 
Published: July 2007

AbstractThis paper considers the fabrication of silicon nitride films by means of the vapor phase deposition with a microwave glow discharge. With a cavity‐type coaxial line microwave discharge tube, a plasma has been confined in a desired space and the film has been fabricated successfully outside the plasma. Hence, the substrate is not damaged nor heated by plasma bombardment. Fabrication has been successful with the substrate at room temperature. The deposition rate depends on the location of the substrate table. When the table is sufficiently far away so that an almost uniform film thickness is obtained for a substrate 6 cm in diameter, the deposition rate is 2 to 7 Å/s with the microwave power of 100 W. Depending on the fabrication conditions, the optical energy gap varies from 2 to 5 eV. Then the color of the film (∼l μm) changes from brown to transparent.A new method has been proposed for finding the Si/N ratio and the film density from the measurement of the infrared absorption spectrum and the index of refraction. Based on the computed results, the film quality has been studied. When the flow rate of SiH4 gas is kept sufficiently small, a sufficiently strong transparent film can be fabricated with the Si/N ratio of 0.75 and the density of 2.3 g/cm3. When the substrate temperature is increased, the film density is increased and the deposition rate is reduced. It is found that the reduction of the deposition rate is due to that of the adsorption rate of the radicals.
A multiinput type converter for an uninterruptible dc power supply
Authors: Koyashiki Tohru , Ogata Tsutomu 
Published: July 2007

AbstractLow‐power uninterruptible dc power supplies have been used widely. These are powered by several types of power sources with differing voltages, e.g., commercial ac power sources as well as batteries. A multi‐input‐type converter is developed to simplify circuit configuration and realize a low‐loss power system.This paper presents a method of designing a multiinput transformer as well as the operation principle of a multiinput‐type uninterruptible power supply and the circuit technology required for it. The power supply can be realized if the transformer primary winding‐turn ratio is designed considering the input voltage variation range and the voltage‐drop in the transformer primary circuit. The fact that the switching‐duty ratio must be changed drastically and that the switching transistor loss is inclined to increase in a multiinput‐type converter causes some problems. It is shown that the application of a collector current proportional drive circuit to the forward‐type converter or a base resistor switching circuit to the flyback‐type converter is effective in reducing the converter loss and the converter can be simplified by using most of the converter circuits in common.
Application of two‐frequency nonlinearity measuring method to contacts
Authors: Minowa Isao , Akiyama Jun , Kanno Makoto 
Published: July 2007

AbstractIt is known that electric contacts, as well as resistors and capacitors, exhibit nonlinearity in their voltage‐current characteristics, although very slight. With the oxidation and contamination on the surface of a contact, the nonlinearity increases with the contact resistance. From such a viewpoint, a proposal has been presented to utilize the nonlinearity in estimating the degradation of contact. In that proposal, the third‐order distortion is detected as the measurement of the nonlinearity. In this study, the two‐frequency method is employed, where a current composed of two frequencies is passed through the contact and the distortion voltage at another frequency is detected. A higher sensitivity than the past method was obtained. By this system, the contact resistance as well as the distortion voltages from second‐ to sixth‐orders can also be measured maintaining the same contact state. To examine the effectiveness of the method, gold‐plated contacts and other kinds were measured. The spectrum features from the second to the sixth distortion can be measured. This provides new information not obtained from the third distortion only. This will be a new method for describing the contact characteristics in the future.
Speech prosthesis system for laryngectomees using “electropalatograph” and a small keyboard
Authors: Muraki Shigeru , Sugie Soboru 
Published: July 2007

AbstractWe have been working on a speech prosthesis system for the past three years. This system utilizes the electromyograph of the laryngectomee who is unable to speak. The detection of the electromyograph, however, involves a number of problems such as noise and electrode attachment. This paper reports on the development of a system which can discriminate and produce a number of monosyllabic speeches from the contact pattern between the tongue and the palate in cooperation with the input from a simple keyboard. A device, called the electropalatograph, detects the contact pattern between the tongue and the palate. The matching between the detected pattern and the preregistered template is examined. Based on the time‐course of the best‐matched template and the input from the simple keyboard, the intended monosyllable is determined. The result drives the speech synthesizer to produce the speech. In the evaluation experiment, 82.4 percent of 63 monsyllables were uttered correctly. Furthermore, the score tended to improve with the training of the patient.
A three‐dimensional process simulator and its application to submicron VLSI's
Authors: Onga Shinji , Taniguchi Kenji 
Published: July 2007

AbstractA three‐dimensional process simulator TRIP for submicron electron device fabrication was developed. TRIP includes, as the process models, the ion‐implantation model, diffusion/oxidation model, and etching model. In the diffusion model, Fick's second equation is discretized by seven‐point difference in the three‐dimensional space. The oxidation‐enhanced diffusion (OED) effect in the oxidizing atmosphere is taken into consideration is determining the diffusion coefficient. The OED effect at the mask corner in LOCOS is extended into three dimensions. The fabrication process of a junction is used to examine the accuracy of TRIP. It was seen as a result that the accuracy is practically satisfactory. Examining the problems in the process design for a submicron MOS device using TRIP, the impurity dilution effect and impurity crowding effect are found as problems peculiar to the three‐dimensional process.
A consideration of discharge phenomena generated in E cross B devices
Authors: Tanizuka Noboru 
Published: July 2007

AbstractSince discharge phenomena are generally complex, a systematic method of interpreting them will be useful for their applications. This paper offers an interpretation of discharge phenomena from the viewpoint of flow, transformation and distribution of energy by taking E cross B devices. The results are useful for designing this type of device. The device constant, k × erB2/8U2, was introduced, where r2 is the radius of the outer electrode, U2 is the electrode voltage, B is the axial flux, and k has a dimension of mass. The energy transformation efficiency, \documentclass{article}\pagestyle{empty}\begin{document}$ \eta = 2h^{ - 2} \sqrt {1 - h^2} \left({1 - \sqrt {1 - h^2}} \right) $\end{document} was found, where \documentclass{article}\pagestyle{empty}\begin{document}$ h = \sqrt {m/k} $\end{document}, and m is the mass of charge (the intermediate charge) which transforms the electrostatic potential energy into the discharge energy. It was found experimentally that this type of device discharges when h < 1. This agrees with the theory that a discharge occurs (0 < n < 1) when h < 1; 1 − n indicates the rate of the kinetic energy (which is the cause of the temperature rise in the device) when the charge m collides with the electrode. It is predicted that the closer the h to zero, the closer the n to 1 and the more effective the discharge.
A method for solving the inverse problem in electrocardiography using a nonlinear torso model
Authors: Akamatsu Norio 
Published: July 2007

AbstractIn the inverse problem in electrocardiography, the information concerning the tissue is known, and the electrical phenomenon in the heart is to be estimated using the measured body surface potential. In the already‐estimated solution of the inverse problem in electrocardiography, the forward solution is determined first, and then the backward solution is derived using the forward solution. In this procedure, an ill‐posed problem may be generated, resulting in an unstable solution, necessitating smoothing. This paper proposes a new method of solution where the backward solution is calculated directly from the surface potential. Due to the ill‐posed condition inherent in the inverse problem in electrocardiography, the potential distribution derived inside the body is oscillatory. The local spatial smoothing is applied to suppress the oscillation. The tissue information is given from Computerized Tomography through an image‐input device. Then a nonlinear network is constructed. The earlier solution method for the inverse problem in electro‐cardiography can only be applied to the linear electrical medium. The proposed method can also be applied to the nonlinear system. This paper describes the solution method for the inverse problem in electrocar‐diography taking the nonlinear conductance into consideration. Examples solved by applying this method are shown. In this method, the deficit of information by excessive smoothing can be avoided. Especially, in the precardial part, the epicardial potential close to the true distribution can be estimated. The proposed method does not require the forward solution. The computation time can be reduced. By employing a successive solution method the memory capacity can be reduced.
Low‐temperature characteristics of buried channel charge‐coupled devices
Authors: Kimata Masafumi , Denda Masahiko , Yutani Naoki , Iwade Syuhei , Tsubouchi Natsuro 
Published: July 2007

AbstractThis paper aims at the improvement of the characteristics of the buried‐channel charge‐coupled device (BCCD), which is used in such low‐temperature operation as the infrared image sensor. The measurement and analysis are performed for the transfer loss of BCCD below 100°K. The transfer loss in this temperature region is dominated by the carrier freeze‐out to the impurity level composing the n‐well of the buried‐channel. The loss in this temperature region depends on the period and the fall‐time of the driving clock. The dependence of the loss on the driving condition can be accounted for by the model in which two time‐constants exist for the emission from the trap. The reason for the different emission time‐constants from a trap depending on time is that the fringing field in the channel depends on time. When a large fringing field exists, the effective barrier of the trap is lowered by the Poole‐Frenkel effect, thereby decreasing the emission time‐constant. To reduce the transfer loss in this temperature region, there are several methods, such as utilization of impurity with shallow donor level in the n‐well of the buried‐channel, reduction of the impurity concentration, and increase of the fringing field.
SAW MSK matched filter and its application
Authors: Tominaga Jun‐Ichi , Shibayama Kimio 
Published: July 2007

AbstractThe SAW device can realize a high‐speed and wide‐band operation. Recently, the application of SAW to the signal‐processing device is considered in the spread‐spectrum communication and in other problems. This paper presents the theoretical and experimental investigations on the construction and characteristics of the SAW MSK matched filter. The device is obtained by combining the SAW filter with the tapped delay‐line and the MSK modulation, which is noted as an excellent means of concentrating the band energy. The construction of the electrode pattern is presented first together with the discussions for the impulse response, frequency response and the correlation characteristics. By experiment and simulation, a method is shown which can improve the amplitude distortion due to the velocity dispersion in the SAW device (substrate) by adjusting the tap intervals. One of the features of this kind of device is that the structure is simple and the signal processing by MSK, such as spread‐spectrum modulation and correlation detection, can be realized by a single kind of element. By utilizing this property, the structure of the communication system can be simplified. As an example of application, a system is constructed where the spread‐spectrum modulation is performed by the proposed device, and the demodulation is made by the correlation detection. Thus, it is demonstrated that such a kind of communication can be realized by a simple structure, indicating the usefulness of the proposed device.
Josephson resistor‐coupled gate considering current density limit
Authors: Yamada Hajime , Tanaka Toshiro 
Published: July 2007

AbstractThis proposes a resistor‐coupled gate with high current density using Josephson elements. In a superconductive logic circuit the input‐output connections must be made using strip lines when the distance between logic gates is increased. In such a case the logic gate must be designed with consideration of the characteristic impedance of the strip line. In the usual design of the logic gate, however, the current density of the Josephson element is limited at the upper and lower sides by the characteristic impedance of the strip line, when the probabilities of punchthrough and misoperation by thermal noise are to be suppressed below a certain value. Then the operating speed of the logic gate is accordingly limited. In order to overcome such limitation, this paper first indicates by calculation that the output voltage should be increased. By connecting two Josephson elements in series, a resistor‐coupled step‐up gate is constructed. This logic gate has the feature that the Josephson current density is increased and the probability of punchthrough misoperation is drastically decreased. A high‐speed logic gate with better overdrive characteristics can be realized. Consequently, the proposed resistor‐coupled gate with high current density can be applied to high‐speed logic circuits.
Fabrication and characterization of titanium dioxide (TiO2)/selenium thin‐film solar cells
Authors: Nakada Tokio , Kunioka Akio 
Published: July 2007

AbstractRecently, Se‐based low‐cost thin‐film solar cells have been developed, resulting in an improvement of the conversion efficiency over conventional Se photocells. Although these solar cells enable increasing the photocurrent increase by designing a thin Se layer, no considerations have been given for the open‐circuit voltage.The TiO2/Se solar cell described in this paper uses n‐type TiO2 with remarkable photoconductivity as a window material. In addition, it reduces the dark current and improves the open‐circuit voltage by operating as an MIS (Metal‐Insulator‐Semiconductor) diode in the dark and as a pn junction under the light illumination. As a result, the open‐circuit voltage has been improved, and a cell with a conversion efficiency of 5.0 percent (short‐circuit current is 10.8 mA/cm2, open‐circuit voltage 0.88 V, fill factor FF 0.53) under simulated AM 1.5 (100 mW/cm2) illumination has been realized. This is the highest efficiency reported to date for Se solar cells.Additionally, since the spectral response is close to the emission spectrum of fluorescent lights, the efficiency improves to 11 ‐ 13 percent under fluorescent lights (500 lux). Furthermore, since these cells have advantages of high sensitivity in short wavelengths, good photocurrent‐illumination characteristics and low dark current, applications not only for solar cells but for light sensors such as color sensors and power meters are also expected.
Analysis of surge and noise generation mechanism in a forward DC‐to‐DC‐converter
Authors: Nakahara Masatoshi , Ninomiya Tamotsu , Harada Koosuke 
Published: July 2007

AbstractThe surge and noise generation in a switching converter depends heavily on the switching speed of the transistor, the recovery characteristics of the diode, the leakage inductances of the transformer and other parasitic inductances, and capacitances. Therefore its mechanism is so complicated that to obtain a complete understanding of the mechanism of surge and noise generation, it is definitely necessary to introduce the analytical procedure through which the quantitative discussions are made. This paper clarifies the mechanism of surge and noise generation in a forward dc‐to‐dc converter which is one of the most popular types of converter. The analysis is performed by partitioning the switching time into several states and deriving a high‐frequency equivalent circuit for each state. The equivalent circuits include not only inductive and capacitive parasitic parameters, but also the parameters related to the switching speed of the transistor and the recovery characteristics of the diode. As a result, the effects of these various parameters on the surge and noise generation are clarified quantitatively.
Evaluation of modal distribution of optical branching waveguide by phase space
Authors: Kokubun Yasuo , Suzuki Senichi , Fuse Tsuneaki , Iga Kenichi 
Published: July 2007

AbstractOptical multimode branching waveguides are very important devices in optical communication systems, but the evaluation method of their characteristics has not been established yet. The design and evaluation of these elements, because of their characteristic dependency on modal distribution, have encountered some problems.This paper proposes a new method to evaluate the characteristics of optical multimode branching waveguides. The discussion covers the two branching waveguides of step‐and graded‐index distributions. First, using the ray‐tracing method, the branching characteristics of multimode branching waveguides are investigated and the condition of equal light intensity is obtained. Then as a new method for evaluating the modal distribution at the output, phase space expression in terms of the ray position and its slope, is proposed. It is shown that the optimum condition for the branching ratio does not necessarily agree with the optimum condition if modal distribution is also considered. Further, a diffused branching waveguide is fabricated and a qualitative discussion is given by comparing theoretical and experimental results.
Analysis of reference‐tap‐voltage fluctuation in flash A/D converter
Authors: Nakaya Masao , Kumamoto Toshio , Miki Takahiro , Horiba Yasutaka 
Published: July 2007

AbstractTo improve the speed and accuracy of the CMOS flash A/D converter using a copper‐type comparator, an analysis has been performed for the voltage variation at each reference terminal of the ladder resistor providing a reference voltage. A model has been developed in which the circuit made of the ladder resistor and the input capacitance of the comparator is treated as a distributed network. A theoretical formula is derived which analytically provides transient behavior of each reference terminal voltage due to change in the comparator. With this formula, it is found that the maximum error of the reference terminal voltage occurs when the input voltage is either 0 or V ref. The error decreases exponentially with reduction of ladder resistors and comparator input capacitances and with increase of time. It is found that the product of the ladder resistor and the comparator input capacitance between adjacent terminals must be less than 5 × 10−13 F.Ω in order to obtain an 8 bit A/D converter with 20 MS/s. Variation is decreased if the midpoint of the ladder resistor is fixed. For instance, when the midpoint is fixed, the product of the ladder resistor and the comparator input capacitance is allowed to increase up to 2 × 10−12 F.Ω.
High‐speed spectroscopic measuring apparatus for contact arc discharges using CCD image sensor
Authors: Sato Kiminori , Sone Hideaki , Echigo Hiroshi , Takagi Tasuku 
Published: July 2007

AbstractNumerous studies have been made on contact arc discharges. However, little has been reported on the detailed measurement of discharge phenomena. With a view to obtaining basic data to be used for the improvement of contact performance, an apparatus has been developed which performs parallel spectroscopic measurement of spectral arc intensities. The arc passing through the spectroscopic analyzer is focused on a CCD image sensor by means of a lens. Each spectral line is correlated to CCD picture elements. CCD has 128 pixels and the apparatus can measure arc spectral lines at 350 ∼ 700 nm in parallel and with a 1 ms interval. The arc voltage and current forms can also be measured. All the data undergo an A/D conversion and are stored on a floppy disk. Hence, the arc discharge can be studied quantitatively and the fine structures in the arc may be analyzed. From the present experiment it is found that the arc is maintained with a larger variety of ambient atoms in the Pb contact arc than in Ag. A transition from the metallic phase to the gaseous phase has been confirmed for the Ag contact arc.
Characteristics of simulation reactance circuits using converter‐type mutators
Authors: Ikeda Katsuji , Tomita Yasushi 
Published: July 2007

AbstractThe mutator proposed by Chua can be classified into two types converter type and inverter type. This paper proposes circuit configurations realizing various converter‐type mutators and studies simulation reactance circuits. It is shown that various converter‐type mutators can be realized by the use of specific two‐ports of active building blocks made of three current converters in which the basic structure is a voltage‐controlled current source and RC elements. Next, for practical simulation reactance circuits made of C‐R, L‐R and D‐R mutators, an analysis has been carried out based on the actual characteristics of current conveyors and an equivalent circuit has been derived. As a result, parasitic elements causing instability of the circuits are identified. The effect of the parasitic elements has been reduced with a passive compensation made of a ground capacitance so that a stable reactance circuit is realized. Further, theoretical and experimental results have been compared and discussed. The validity of the equivalent circuit is confirmed.
Bit‐map CAD system of IC design employing BIT‐I language
Authors: Koide Hideki , Kim Chol , Shono Katsufusa 
Published: July 2007

AbstractThis paper describes the IC design language BIT‐I implemented on a personal computer, and the bit‐map CAD system employing the language. The system is composed of several programs covering the mask pattern design, design rule check, extraction of circuit parameters, function simulations, and conversion of data formats. Actual data processing in the program of design rule check and extraction of circuit parameters consists of the combinations of basic logic operations. The basic logic operations are described in the subprograms and their combinations are described in the main program. Therefore when new programs are to be developed for different water fabrication process or different devices, only the development or modification of new main programs can manage them.
Electrically deposited germanium–coated circular metallic hollow waveguides for infrared radiation
Authors: Miyagi Mitsunobu , Shimada Youichi , Nishida Shigeo , Hongo Akihito 
Published: July 2007

AbstractAn electrically plated germaniumcoated circular metallic hollow waveguide was fabricated to transmit CO2 laser light. The conditions for the plating current, the temperature of the plating bath, and the plating period have been established. The transmission characteristic of a circular hollow waveguide 4 mm in diameter and 1 m long has been measured and its low‐loss characteristic has been confirmed.