bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast channel impulse response estimation scheme for adaptive maximum likelihood sequence estimation equalizer—proposal of variable‐gain least mean square algorithm
Authors: Denno Satoshi , Saito Yoichi 
Published: July 2007

AbstractThis paper discusses the channel estimation algorithm in the adaptive maximum likelihood sequence estimation (MLSE) and proposes the variable‐gain least square (VLMS) algorithm that can realize a fast acquisition by a simple configuration. When the sent code is a random sequence, VLMS is represented by a deterministic canonical equation based on the fact that a deterministic autocorrelation matrix for VLMS can be diagonalized.It is shown that VLMS can be realized with nearly the same computational complexity as least‐mean square (LMS) algorithm. It is shown theoretically by analysis that VLMS can realize the same fast acquisition and tracking characteristics as those of the recursive least square (RLS) algorithm. An algorithm also is derived which is an extension of the basic idea of VLMS and can be used for the fractional MLSE equalizer. It is shown experimentally that the fractional MLSE equalizer with VLSE algorithm can compensate the performance deterioration due to the sampling phase error. In the two‐wave Rayleigh fading environment with faT = 4.0 × 10−4, the floor error can be suppressed below 10−4. It is shown also experimentally that the proposed equalizer has an excellent synchronization performance in which the initial acquisition can be completed in approximately six symbols.
Antenna factors of half‐wavelength dipole antennas with roberts balun
Authors: Kim Ki‐Chai , Tokumaru Shinobu 
Published: July 2007

AbstractTo use antenna factors most effectively in either EMI measurement or the reference antenna method, the antenna factor is more accurately derived than the conventionally obtained value when a half‐wave resonant dipole antenna with Roberts balun (ANSI C63.5 Specification) is placed on the ground plane. In the calculation, the antenna is treated as the boundary value problem of Maxwell's equations and is analyzed by the Galerkin moment method. The balun is treated using circuit theory based on power transmission mismatch. To confirm the validity of these theoretical calculations, the computed value of the antenna factor in free space is compared with the measured results by the standard site method and the standard antenna method. It is confirmed that the tendency of the numerical results agrees well with that of the measured values.
Measurements and analyses of multipath propagation structure for small‐cell digital mobile radio in hilly areas
Authors: Laksono Trisila Heru , Maeyama Toshiyuki , Kitano Yasushi , Ikegami Fumio 
Published: July 2007

AbstractFor research on characterization and reduction of the bit error rate in high‐speed digital mobile communication, the understanding of the multipath propagation structure is indispensable. In this research, a measurement system is developed in which the two sets of directive antennas and the delay time measurement method by TV video signals with a sharp pulse inserted are combined.The multipath propagation structure is measured in detail in hilly small‐cell model areas. In addition to conspicuous reflections from the buildings and hills around the measurement course, the reflected waves from far away buildings and multiple (several times) reflected waves are observed. The power‐delay profiles and the nature of the delay spread of the multipath waves are analyzed so that the effect of the delayed multipath waves on the bit error rate in the digital transmission is found.
Magnetic layer design considerations for highly durable recording tape
Authors: Iijima Tetsuo , Hosokawa Shigefumi , Hiratsuka Hiroaki 
Published: July 2007

AbstractAmong magnetic recording tapes for such applications as mass storage systems, the antiabrasion properties of the magnetic layer along with storage life are major factors determining magnetic tape life. This paper examines the effect of magnetic layer structural parameters which affect durability and the signal‐to‐noise ratio. Several magnetic tape layer design conditions aimed at improving magnetic tape reliability and recording density are then presented. That is, in order to effect a highly durable binder structure, it is necessary to achieve appropriate mechanical characteristics (tensile strength ≥1 kg/mm2 and elongation at break ≥40%) by crosslinking a large‐matrix, high‐molecular weight polyurethane as well as carefully adjusting the balance of each additive. On the one hand, lapping treatment is effective in improving the SN ratio, with a decrease of up to two‐thirds in surface roughness possible. At the same time, it is found that magnetic pigment content is an important factor limiting durability and that it is a sensitive structural parameter which must be determined based on its inverse relation to the SN ratio. Using a specially developed binder, we demonstrate that a highly durable magnetic tape capable of withstanding more than 108 head scan passes is possible, that the use of lapping treatment can improve the SN ratio by 4 dB, and that a suitable value for the magnetic pigment content is on the order of 68‐72%.
Electrical characteristics in indium thin oxide (ITO)/selenium heterojunction
Authors: Nakada Tokio , Kunioka Akio 
Published: July 2007

AbstractAlthough low‐cost solar cells based on Se have recently been examined, there have been extremely little basic data which provide a guideline for the improvement of energy conversion efficiency. In this paper, to clarify the behavior of heterojunctions between Se and conductive oxides, an ITO/Se heterojunction has been fabricated and its basic electrical characteristics and impurity concentration distribution by x‐ray photoelectron spectroscopy have been studied. The ITO/Se heterojunction can be regarded as a Schottky contact based on capacitance‐voltage (C‐V) and photoelectric response characteristics. Also, in the current density‐voltage (J‐V) characteristics, the slope of ln J vs. V is constant regardless of temperature. This has been explained in terms of the tunneling mechanism through interface states; Te (20 Å) introduced at the ITO/Se interface not only prevents the peeling of Se film during the thermal crystallization process, but also improves the diffusion potential and the barrier height by 10%. Although a part of the Te thermally diffused into Se layer forms an acceptor level and changes the impurity doping distribution, it does not especially affect the energy band, the J‐V characteristics or the spectral response. Since the diffusion potential determined from the C‐V characteristics is approximately 1.5 times the open circuit voltage under AM illumination, this implies that SIS (Semiconductor‐Insulator‐Semiconductor) structures are more suitable for Se‐based solar cells.
Theoretical investigation of a gap coupling of two dielectric slab waveguides with arbitrarily shaped ends
Authors: Nishimura Eiichi , Morita Nagayoshi , Kumagai Nobuaki 
Published: July 2007

AbstractAn integral equation method is used to analyze the scattering of the incident guided mode at the gap between two dielectric slab waveguides with arbitrarily shaped ends. As a typical example, a two‐dimensional model of the coupling gap, which occurs in the preheating stage of the fusion splicing of optical fibers is treated. The possibility is studied for indirect understanding of the situation of the coupling location from the measured values of the reflected light, transmitted light, etc. A detailed study is done for the correlation of the reflected, transmitted, radiated power and radiation patterns with the gap width and the end shape (functions of the preheating time). The reflected, transmitted, and radiated power change quickly within a short period but without significant characteristics. However, their envelopes indicate characteristic tendencies. The maximum of the reflected power and the difference between the maximum and minimum of the transmitted power decrease monotonically. The backward, rather than forward, radiation pattern varies more sensitively to the change of the end shape.
Analysis and characterization of corrosion products on gold‐plated contacts for electrical contacts
Authors: Ishino Masakazu 
Published: July 2007

AbstractMethods for measuring the thickness and composition of corrosion products due to pin‐holes on gold‐plated contacts using an energy dispersive X‐ray analyzer are described. The thickness and composition of the corrosion products measured using the methods are also described, and their effects on electrical characteristics of the contacts are discussed. The thickness of the corrosion products is about 1 μm at the center of the pinhole and decreases in the peripheral area. The corrosion products in the peripheral area consist mainly of copper sulfate of lower resistivity and less copper oxide which has higher resistivity. This results in higher contact resistance in the center of the pinhole and lower contact resistance in the peripheral area. However, the contact resistance rarely exceed 60 O even at the center. Electrical and mechanical breakdown phenomena of the corrosion products are also discussed. It is shown that continuous poor contact is rarely caused by corrosion products on gold‐plated contacts.
Suppression of noise of echo sounder using exponential smoothing method
Authors: Shigeyasu Kuniyuki , Ogasawara Motoyasu 
Published: July 2007

AbstractThe method of noise cancellation of echo sounder using a logical data product has been used in the presence of clutter noise and interference noise. However, significant data for multioverlapping noise cancellation may be eliminated by this method. To solve this problem we study the noise suppression by the averaging method and select an exponential smoothing method which requires a small amount of memory and is computed quickly. Additionally, by using jointly a table‐lookup method for division, the computation time is shortened considerably. Consequently, it becomes clear that noises on color display are suppressed remarkably and schools of fish are revealed clearly due to the smoothing effect. This paper discusses the application of the exponential smoothing method to noise processing and its effectiveness.
Transmission characteristics of one‐dimensional image fiber‐strong coupling case
Authors: Mori Kensuke , Yamaguchi Shoji , Hosono Toshio 
Published: July 2007

AbstractWhen an image is transmitted over a long distance by an image fiber in which a great number of homogeneous fibers is bundled, cross‐talk (mode coupling) is easily introduced and the resolution is decreased by blurring. In this paper, an exact numerical analysis of the transmission characteristics (cross‐talk characteristics) of one‐dimensional image fiber, constructed by arranging a finite number of homogeneous dielectric slabs at equal spacing, is carried out by means of wave‐optics for the strong coupling as well as the weak coupling case. The main conclusions drawn from this research are:(1) The weak coupling approximation theory on the cross‐talk characteristics of the image fiber is applicable to the case, which is usually considered as strong coupling.(2) When N element fibers are bundled in an image fiber, the mode generation is removed and each mode of single fiber separates into N different modes, some of which, if coupling is too strong, may turn into leaky modes.(3) The girth of the image fiber has an effect similar to that of a perfect conductor.(4) If the mode coupling in an image fiber is used deliberately, the structure can be used as a spatial image processing element such as planar lens, spatial filter, etc.
Electrical properties of anodized hf thin‐film capacitors
Authors: Noya Atsushi , Umezawa Toshiji 
Published: July 2007

AbstractThin‐film capacitors of Hf‐HfO2‐Al are fabricated by anodizing the Hf film deposited on a glass substrate by r.f. diode sputtering. The dependence of electrical properties on the anodizing voltage and the heat‐treatment temperature has been studied experimentally. In the capacitor fabricated with anodizing voltage of 40 V, the capacitance density is found to be 0.257 μF/cm2 and an appropriate heat treatment can improve the tan Δ of 0.0026 and the temperature coefficient of capacitance of 230 ppm/°C. These values are comparable to those for the capacitor with the anodizing voltage of 160 V. The capacitor electrical properties improve with heat treatment in the temperature range of 100 to 300°C so that the thermal stability is increased. It has been confirmed from these results that the anodized Hf thin film can be a useful dielectric material for a capacitor with a large capacitance density fabricated with a low anodizing voltage. By means of Auger electron spectroscopy, the depth profiles of these capacitors have been studied. The thickness of the nonstoichiometric interface layer between the anodized oxide and the base hafnium metal varies by the anodizing voltage and the heat treatment. The tan Δ of the capacitor is especially closely related to the thickness of the interface layer.
Temperature resolution of a noninvasive thermometry for hyperthermia using NMR
Authors: Kamimura Yoshitsugu , Amemiya Yoshifumi 
Published: July 2007

AbstractThermometry of the deep interior of the human body should be realized in a noninvasive way when clinical hyperthermia is applied to cancer therapy. This paper describes temperature resolution of a noninvasive thermometry using temperature dependence of the thermal equilibrium magnetization MO in the nuclear magnetic resonance (NMR) measured by the magnetic field focusing method.In this paper, it is assumed that temperature errors are caused by: (a) the relaxation time; (b) incomplete focus; and (c) the thermal noise of the measurement system when (1) the temperature dependence of MO approximates to water, and (2) the influence of blood flow is negligible except in the main arterial region. The effects on temperature errors are studied and, as a result, the relations between the temperature errors and parameters of the measurement instrument are determined quantitatively. For example, a temperature measurement with an error of °0.5°C in a small cylinder 4 cm in diameter and 4 cm long requires that the current for a line‐shaped magnetic field and the current for gradient field be 9.89 kAT and 2.51 kAT, respectively. Here, the resonance frequency is 4 MHz and the cut‐off frequency of the low‐pass filter is 100 Hz.
High‐speed thin‐film thermal print head
Authors: Shibata Susumu , Kanamori Takashi , Kuroki Kenji 
Published: July 2007

AbstractThis paper describes the result of thermal analysis of the inner region of the thin film thermal print head and the effect of the shape of the meander type heating resistor. The thermal head allowing short pulse driving for higher speed with higher reliability has been demanded recently. The influence of the pulse duration on the temperature profile of the inner region of the head and the heating resistor shape have not been studied.We have studied various conditions affecting the temperature profile of the inner region of the thin film thermal print head and the shape of the meander type heating resistor, and obtained the following results:1. As the pulse applied to the heating resistor gets shorter, the necessary power for pulse application increases and the temperature slope in the heat insulating layer near the heating resistor becomes steeper.2. To lessen the temperature slope in the heat insulating layer, thinning the protective layer, increasing the thermal conductivity of the protective layer and preheating the whole inner region are effective.3. In surface temperature distribution, corners of the meander type heating register become hotter as the width of the pulse applied to it becomes shorter. Widening the heating register at corners, narrowing the straight parts and increasing the number of meanderings are effective.
SHG in a slab‐type waveguide with a 2‐methyl‐4‐nitroaniline crystal as a high index top layer
Authors: Sasaki Keisuke , Kinoshita Takeshi , Karasawa Naoki 
Published: July 2007

AbstractRecently, it has been recognized that organic materials have a very large nonlinear optical constant compared with non‐organic materials (e.g., KDP and LiNbO3). It has been known that 2‐methyl‐4‐nitroaniline (MNA), among them, has an extremely large SHG tensor, although this has a disadvantage in that the d11 component cannot be matched in phase in the bulk crystal state. When an MNA single‐crystal made by using the vapor‐phase method and shaped in a thin parallelogram, is set on a tapered slab‐type thin‐film waveguide appropriately, and the fundamental wave is applied as a TE wave, it is possible to match the phase of the fundamental wave and the phase of the second harmonic wave at a certain waveguide thickness. Since the refractive index of the MNA is greater than that of the slab‐type waveguide film, an SHG is observed at the resonating film thickness when the high‐refractive‐index top layer is used. The observation of the second harmonic (0.532 μm) was made by using an Nd:YAG pulse laser (1.064 μm) for the fundamental wave. The phase matching point was examined from the dispersion curves which was calculated from the waveguide structure parameter. The results show that this phenomenon is the conversion from the TE first of the fundamental wave to the TE second of the secondary harmonic. The efficiency of the MNA observed was not great since the overlapping of the two wave types is not large.
Brightness distribution in rf‐sputtered zns:tbf3 electroluminescent panels
Authors: Mikami Akiyoshi , Ando Keiichi 
Published: July 2007

AbstractThin‐film ZnS:TbF3 was deposited by sputtering and a thin‐film electroluminescent panel having a display area of 34 mm × 34 mm was fabricated. The brightness distribution was investigated and film thickness variation and distribution of Tb luminescence centers were studied in conjunction with the brightness. It was found that uniformity of the brightness increases as the applied voltage increases and frequency decreases. Relative brightness deviation (Bmax ‐Bmin,)/Ba, where Bmax, Bmin and Ba indicate maximum, minimum and average brightness, respectively, of the film was 13 to 23% when it was driven by 5 kHz, 40‐V voltage. It was observed that brightness distribution depends on film thickness of the ZnS:TbF3 layer and that the thinner part has higher brightness. Based on the consideration that thickness variation causes irregular field intensity as well as the conduction charge distribution, and results in brightness variation, we calculated the brightness deviation and found that it agreed well with the experimental results. It was also demonstrated that Tb ions were scattered uniformly in the sputtered ZnS film, which was proved to have uniform luminescence center distribution.
Edge‐junction type nanometer bridge
Authors: Yamashita Tsutomu , Hamasaki Katsuyoshi , Matsumoto Kazutaka , Kodaira Yoshimitsu , Komata Toranosuke 
Published: July 2007

AbstractAn edge‐junction type nm (nanometer) bridge is fabricated which has bridges on the joint of the edges of two Nb films. Each nm bridge has an effective length of less than 50 nm, width about 2 μm, and thickness from 30 to 60 nm. To make a good edge‐junction type nm bridge, it is necessary to form a sharp edge on an Nb film. For this purpose, dry‐etching with a teflon holder in an He gas was used. Voltage steps up to about about 100 μV induced by a microwave were observed in the fabricated device, and the value of IORn greater than 50 μV was obtained. By measuring the threshold characteristic of a DC‐SQUID consisting of this nm bridge, it was confirmed that the current‐phase relation of the bridge is sinusoidal. The temperature range in which this sinusoidal relation is kept is as wide as 4 to 6 K approximately.
Thin‐film energy‐transfer dye lasers in spectral region of near ultraviolet to violet
Authors: Muto Shinzo , Shiba Fumikazu , Sano Seigo , Ito Chiaki , Inaba Humio 
Published: July 2007

AbstractThe development of the thin‐film waveguide dye lasers has created extensive applications in laser technology and fiber optics. This paper reports the laser properties of two types of thin‐film energy‐transfer dye lasers (thin‐film ETDL). One is the mixture‐type doped with a donor‐acceptor dye pair in the polymer thin‐film waveguide, which operates largely by nonradiative resonance transfer; the other is two‐layer type with the active core (layer of acceptor dye) and clad (layer of donor dye), which operates only by radiative transfer. These ETDLs are pumped by an N2 laser and operate efficiently as practical compact laser sources in the spectral region of near ultraviolet to violet. Furthermore, the measurement of the energy transfer rate constants in these ETDLs is also presented.
A new thin‐film electroluminescent device with a gate layer and its properties
Authors: Hirate Takashi , Ito Takahiro 
Published: July 2007

AbstractA novel structure is proposed for thin‐film EL devices which incorporates a gate layer (of various materials) into the active layer (ZnS, etc.) of a conventional insulator‐active layer‐insulator structure. Such devices have been fabricated and their characteristics investigated. The result was that especially for gates made of metal or semiconductor materials, characteristics completely different from conventional devices were found. That is, when a metal or semiconductor gate had a thickness of ≥1000 Å, only one of the two active layers sandwiching the gate exhibited luminescence, and which one, was the opposite in the metal and semiconductor cases. Further, for an Al gate, the single luminescent active layer was reversed for thick and thin (200 Å‐500 Å) gates and making the gate even thinner (∼100Å) resulted in both layers being luminescent. In this latter case, a very significant result was obtained that by doping the active layers with ErF3 and SmF3, respectively, a continuously variable color ranging from light yellow to orange could be obtained by changing the driving voltage or frequency.
A switching‐mode ultralow‐frequency signal delayer and its application
Authors: Sekiguchi Tsutomu , Tsukamoto Kazumi , Kaku Shukichi , Shimooka Yasuyoshi 
Published: July 2007

AbstractThe signal delayer is presently an important device in measurement and automatic control. The schemes for the signal delayer presently used have some problems. This paper extends the already‐known PWM delay method [1] and proposes an ultralow‐frequency signal delayer achieved by means of the switching‐mode system, which controls the on‐phase of the switching element based on the comparison point information between the input signal and the specified bias. The principle and the basic configuration are described first. The operating signal waveform of the proposed signal delayer is analyzed. The condition for the output signal and the possible range of generated signal waveforms are discussed. Then a delay method by waveform conversion is described based on the principle of the switching‐mode operational amplifier, indicating the applications to various kinds of ultralow‐frequency signal generators. An experiment was performed of the comb filter composed by the delayer. It is shown that the system can be used as an ultralow‐frequency difference device and can be applied to the arbitrary transfer function generator and waveform equalizer. In particular, it is shown that the device is useful as a high‐power delay operator for ultralow‐frequency regions.