bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation method for scattering cross section of a dielectric sphere considering resonance phenomena
Authors: Ando Toshikazu
Published: July 2007

The scattering cross section of the dielectric sphere was expressed in infinite series by Stratton. However, this series is difficult to calculate. In the conventional calculation, the applicable ranges of parameters are limited and the number of terms required for infinite series calculation is not clear. Further, the relation between the resonance of dielectric spheres proposes a new calculation method. The fundamental nature of the resonance of the dielectric sphere is discussed and calculation methods for spherical Bessel functions of complex variables and spherical Hankel functions required for scattering cross‐section calculations are presented. The resonance characteristics of the dielectric sphere are calculated with various parameters and the method of determining the number of terms in the calculation of infinite series is examined. This method is applicable for the calculation of scattering wave from the infinite dielectric cylinder.
Optimum magnetic circuit design for small DC servometers based on numerical analyses
Authors: Itoh Hisayasu
Published: July 2007

For the purpose of miniaturization of DC servomotors with slotted armatures of the side‐leg type, a numerical analysis is made, taking into account magnetic circuit configurations and materials i;the magnetization characteristics of each section are obtained and the optimum circuit design conditions are specified.

For a side‐leg type structure using the rare‐earth magnet, the numerical analysis is made using the difference method and the circuit is divided into main and leakage portions. The design approach is to deal first with the main circuit, in which magnetic saturation is considered, and then to consider the leakage circuit, with the operating points of the magnet made equal. The structure as related to leakage permeance is specified quantitatively. For the armature tooth section constituting the main circuit is analyzed, considering saturation, and the flux density distribution together with the magnetic potential drops as the air‐gap flux increases, are obtained for each section. Based upon these analytical results, the optimum circuit design conditions to yield the maximum power rate‐to‐weight ratio are demonstrated and the relation between material and performance limitations are given.
General expressions for attenuation‐characteristics of submarine coaxial cables at high frequency
Authors: Ashiya Fumihiro , Furukawa Shin‐Ichi , Negishi Yukiyasu , Kojima Nobuya
Published: July 2007

An expression for the attenuation loss of submarine coaxial cable systems must provide a precisely calculated attenuation loss at any frequency in the environments of temperature T and water pressure P. The expression, based on the cable loss characteristics measured at atmospheric pressure on land, must yield an accurate estimate of the cable loss characteristics at the sea bottom.

Here, we propose a general expression for the attenuation as a function of f, T and P. The expression is based on some material characteristics and sizes, which are the basic parameters defining the transmission characteristics of a submarine coaxial cable. Owing to the introduction of a polynominal representation for the dielectric loss characteristic tan δ which has hitherto not been taken into account, we were able to derive an expression for the attenuation vs. temperature and water‐pressures and to demonstrate explicitly that variations in attenuation caused by temperature and water pressure changes can take the form of polynominal equations in f, T and P. Further, we shall introduce a finite‐order, simple and practical polynominal formula as. an expression for the case when some limitations are allowed on the frequency and on the accuracy of calculating the attenuation.
Fast and accurate electron‐beam deflection circuits using two kinds of D‐A converters
Authors: Wada Yoshifusa , Migitaka Masatoshi , Hisamoto Yasuhide , Mizukami Koichiro
Published: July 2007

This paper presents results of the investigation on the characteristics of the electron‐beam deflection circuit which utilizes a fast D‐A converter and a high‐resolution D‐A converter. The scanning rate depends on glitches of the fast D‐A converter. The setting time calculated by the first‐order approximation model agrees well with the measured result. If the newly proposed deglitching circuit was used, the glitches were reduced to below 10% and the settling time for ±0.0004% was 0.7 μs. The deflection signal stability depends on the high‐resolution D‐A converter. The short‐term stability was ±1 ppm/10 hours without temperature compensation. The long‐term stability with temperature compensation was ±3 ppm/1 month.
Decision method of expansion coefficients for finite fourier series by partial sampling values
Authors: Iijima Taizo
Published: July 2007

According to the well‐known sampling theorem, expansion coefficients of a finite Fourier series can be determined from a properly selected finite linear sum of all sampling values which correspond to equally spaced division points in the entire interval of the period. In this paper, the sampling theorem is extended to the case where sampling points under consideration do not necessarily spread out on the entire interval. The first half of this paper considers the case where the sampling point interval is equal to an inverse of integer multiple of the period. The second half considers the more general case and general solutions for the successive extrapolation method are derived in a linear recursive form. This method enables one to calculate frequency components from the waveform which was observed successively at constant pitch.
Restoration of gaussian images by two‐dimensional maximum a posteriori estimation
Authors: Akashi Akira , Mizoguchi Riichiro , Yanagida Masuzo , Kakusho Osamu
Published: July 2007

This paper considers the restoration problem for images degraded by superposition of normalized white noise, under the assumption that the discrete sampled signal of the image is a two‐dimensional stationary stochastic process, and discusses a new method of restoring images obtained by extending the maximum a posteriori estimation to the two‐dimensional case.

The image signal has essentially a two‐dimensional nature and in that sense a comprehensive approach based on a two‐dimensional image model is more suited to the image restoration than recursive processing based on a one‐dimensional image model. From such a viewpoint, this paper first extends the maximum a posteriori estimation to the two‐dimensional case based on the two‐dimensional image model for the purpose of image smoothing. Then, it is shown that the system of equations for the estimation obtained by the proposed estimation method can be represented by a matrix equation, regarding the image as a matrix. It is also shown that the smoothing estimation for the image is obtained as a solution matrix by a simultaneous processing by matrix manipulation. Lastly, computer simulation is presented, indicating the effectiveness of the proposed method.
Instability and fluctuation in the Hodgkin‐Huxley model axon
Authors: Harada Kouhei , Hirakawa Kazuyoshi
Published: July 2007

The analysis is made for hard‐mode instability in the Hodgkin‐Huxley model (H‐H model) axon and fluctuations near instability points under the current‐clamp condition. When stimulating currents reach 9.8 μA/cm2, the steady‐state solutions of the Hodgkin‐Huxley equation become unstable and stable limit cycles appear. The fluctuation at a certain frequency is greatly enhanced near instability points due to an increase of irreversible circulation of the fluctuation. The membrane impedance shows a sharp peak in this region. In the H‐H model, circulation equilibrium is maintained below instability points. For I = 9.8 μA/cm2, hard‐mode instability occurs due to increasing fluctuation of a certain oscillation mode caused by sharp frequency responses of the system. This result can explain qualitatively the critical slowing‐down phenomenon and a sharp peak in fluctuation spectrum observed experimentally.
Inverse quantization method for digital signals and images—area approximation type
Authors: Isomichi Yoshinori
Published: July 2007

In transmitting and storing signals and images, the information content of the signals and images must be compressed using sampling and quantization techniques. This paper examines a generalization of the sampling theorem permitting a realistic observation window and proposes a new inverse quantization method suitable for this generalized sampling and usual quantization.
A design method of circularly polarized rectangular microstrip antenna by one‐point feed
Authors: Haneishi Misao , Yoshida Shinichiro
Published: July 2007

This paper describes a method for designing backfeed‐type one‐point fed circularly polarized antennas. These antennas are fed at one point from the back side of the substrate and have degeneracy‐resolving segments. Characteristics of the rectangular microstrip antennas with degeneracy‐resolving segments are obtained by means of a variational method. The equivalent circuit at and near the resonance with perturbations is obtained and the condition for circularly polarized antennas is found from both theoretical and experimental viewpoints. Configurations and radiation characteristics of these antennas are discussed and it is shown that these antennas can be used as array elements.
Broad‐band guided‐wave light intensity modulator
Authors: Izutsu Masayuki , Sueta Tadashi
Published: July 2007

With a view to realizing a broadband guided‐wave light intensity modulator, we fabricated a traveling‐wave type guided‐wave light intensity modulator. We succeeded in experiments of light intensity modulation over 18 GHz. In this paper, the traveling wave operation is shown to be superior almost always to the conventional lumped element operation in terms of bandwidth and efficiency. As an electric circuit appropriate for the traveling wave operation, the effectiveness of nonsymmetric electrodes is described. Analytical results are shown for the transmission line constants and modulation frequency characteristics. Next, the push‐pull optical modulation which is useful to obtain an efficient optical intensity modulator with good optical characteristics is considered.

The configuration for the optical circuit is studied and the possibility of obtaining a traveling wave operation is discussed. Further, the result of the prototype development and modulation experiment using a Ti diffused LiNbO3 optical waveguide (c plate) is reported. The device consists of two branches made of a single transverse mode waveguide 5 μm wide, and a differential modulation portion with parallel waveguides. The electrodes are nonsymmetric transmission lines with separation 32 μm, width 20 μm and length 6 mm. The half wavelength voltage was 8.8 V, extinction ratio 98%, 1/√2 bandwidth 11.2 GHz and the modulation input power 130 mW for 88% intensity modulation. The modulation sensitivity was 11.3 μW/MHz, and the frequency characteristics were found to be excellent.
Two‐dimensional arrays and finite‐dimensional commutative linear representation systems
Authors: Matsuo Tsuyoshi , Hasegawa Yasumichi
Published: July 2007

As an application of realization theory for nonlinear systems, the authors have proposed a realization problem for arrays leading to the following realization theorem. “For a given arbitrary array, there always exists a canonical commutative linear representation system that realizes (computes) the array and is unique except for isomorphisms.” This paper discusses a finite‐dimensional commutative linear representation system that is manageable in practice. The notion of the pseudo‐realizable canonical form is introduced and the principal findings are as follows. (1) Among the isomorphism classes of finite‐dimensional canonical commutative linear representation systems, there always exists only one pseudo‐realizable canonical system. (2) Two necessary and sufficient conditions are derived for the array to be a behavior of a finite‐dimensional commutative linear representation system. (3) A realization procedure is described for deriving the pseudo‐realizable canonical form from the given array. The proposed theory of the finite‐dimensional commutative linear representation system is an extension of the theory of the finite‐dimensional constant‐coefficient linear system. The theory is also adapted for handling arrays on a digital computer.
LPC peak weighted spectral matching measures
Authors: Sugiyama Masahide , Shikano Kiyohiro
Published: July 2007

This report proposed an LPC peak weighted spectral matching measure, a voice recognition method with weighted global spectral peaks (formants), and demonstrates its usefulness by comparing it with the conventional LPC matching measure. The “peak weighted measure” is defined by the integral of the product Kw, where K is a function representing spectral differences between the standard pattern and input voice and w is a weighted function representing peaks. It is shown that the integral value can be computed simply by LPC analysis parameters. Analysis of the weighted spectral difference Kw shows some variation in effectiveness of peak weighting.

Experiments on vowel discrimination to evaluate the measure conclude that the discrimination error rate of 11.7% in the conventional LPC matching measure can be reduced to 9.3% by using the peak weighted measure and, especially, it is remarkably improved for the vowels /a/, /u/, /o/. Further, the variance of the discrimination error rates by speakers is smaller than that of the conventional LPC matching measure.
Linear and nonlinear analysis of electromyography time series
Authors: Ishii Naohiro , Iwata Akira , Suzumura Nobuo , Yamazaki Yoshiki
Published: July 2007

The purpose of this paper is to extract the information of the posture control of an experimenter standing on a plate. In the experiment, the object is vibrated sinusoidally in the vertical direction on the plate and the electromyography (EMG) and force on the plate are measured. A method of estimating the delay time of the system, the system response of the position component and the velocity component of the input is developed. The pseudo‐white noise is constructed by changing the angular frequency of the input. It is shown that the EMG and the force are well represented by a nonlinear input‐output relation.
A novel radar reflector with variable RCS
Authors: Kotajima Hiroshi , Fujita Hirotoshi
Published: July 2007

It is convenient to have a standard radar reflector with a variable radar cross section when the reflection characteristics of radar reflectors and various objects are measured or when performance tests of radar systems are carried out. There have been several proposals for such radar reflectors in the past. However, since all of them make use of reflection of the conductor surface, their reflection efficiency is too low to be practical. The principle of the radar reflector reported in this paper is completely different from that of conventional ones and makes use of focusing and spherical symmetry of the Luneburg lens. The reflection efficiency is quite high and the radar cross section can be varied in response to the rotating angle of the lens. First a method is proposed to obtain a desired radar reflector and the design and fabrication method are described. Further, by means of a prototype development and subsequent measurement is is shown that the proposed method is realizable. As an example, the prototype reflector for a horizontally polarized wave of 9375 MHz is made using a Luneburg lens with diameter of 30.5 cm. The radar cross section can be varied from 43.28 m2 to 0.42 m2 as designed.
Separation of kernel in the hexagonal discrete fourier transform
Authors: Morikawa Yoshitaka , Hamada Hiroshi , Yamane Nobumoto
Published: July 2007

For the two‐dimensional signal with circular band‐limiting in frequency space, a square arrangement of sampling points in the real space is usually used. Assuming, however, that the signal is band‐limited in a hexagonal region, being regarded as periodic and adopting the triangular sampling point arrangmeent in real space, the number of sampling points can be reduced by 13.4% that in the usual method. Mersereau has derived a discrete Fourier transform (DFT) for a two‐dimensional signal hexagonal band‐limited both in real and frequency spaces. In his method, however, separation of the Fourier kernel is impossible and Rivard's FFT algorithm is not applicable to the computation of hexagonal DFT. The authors introduce a periodic extension vector system and sampling point generating vector system. By a generalized method, the two‐dimensional DFT is reformulated. It is shown that the kernel can be given a separable expression by suitable choice of coordinates as in the square DFT, actually presenting the method of determining the coordinate. When the kernel of a hexagonal DFT is separable, the computation reduces to that of the one‐dimensional DFT. This permits the application of already developed FFT algorithms, enlarging the range of utilization of the hexagonal DFT.
Theoretical study on cantor function‐like response characteristics of neuron model
Authors: Osada Hiroyasu , Yoshizawa Shuji , Nagumo Jin‐Ichi
Published: July 2007

When a pulse series with fixed frequency is applied to a neuron model employing tunnel diodes, the firing frequency of the model increases with increasing pulsewidth. The relation between these two quantities can be described by an extended Cantor function. This is identical to the abnormal phenomenon which Harmon discovered experimentally with a neuron model using transistors. One of the authors derived the same result for Caianiello's neuron model which was given by nonlinear difference equations. The neuron model discussed in this paper is described by the first‐order nonlinear differential equation and two jump conditions. The authors predict that the Cantor characteristics can be found experimentally in actual nerve cells.
Trunk reservation for two‐way trunk group with overflow input
Authors: Machihara Fumiaki
Published: July 2007

The total blocking probability for three types of calls and the individual blocking probabilities for each type of call are analyzed for the case where the trunk reservation system is applied to a two‐way trunk group and priority is assigned to the downward first‐routed traffic, the upward first‐routed traffic and the alternate‐routed traffic in that order. The analysis is outlined below.

First, we analyze the transition proabbility of simultaneous circuit connections in the circuit holding model M1, M2/M/n(n2) with due regard to the downward first‐routed traffic and upward first‐routed traffic only, which have Poisson distribution. This analysis involves difficulty in numerical computation because the occurrence rate depends on the number of simultaneous circuit connections and hence it has not been solved yet. We solve it here by introducing the characteristic eigenvalues of system generation operators. Then we mark the instants at which overflow calls of the alternate‐routed traffic arrive at the two‐way final trunk group. Accordingly, this model can be considered as applying regenerative inputs to the above‐described M1, M2/M/n(n2). Therefore, the individual blocking probability for each type of call is introduced by using the piecewise Markov process. The total blocking probability can simply be given through the individual blocking probabilities. Numerical computations are performed and reservation effects are quantitatively shown.
Multiple communication bus network
Authors: Kajiwara Masaichi , Hishinuma Chiaki , Itoh Masaki
Published: July 2007

A multiple communication bus network (MCNET) is proposed as a structure for a nationwide trunk network and its optimum method of circuit regulation and size of the network are discussed. MCNET is a network in which uniform, large‐capacity transmission paths achieve bus connection of plural exchange offices in a region and in which interoffice traffic is directly switched on transmission paths in bus form. Between different regions, the network is hierarchically structured with representative exchanges in regions and bus‐formed transmission paths between them. This paper describes the fundamental concepts and network structure. The circuit regulation method by which circuits are assigned semipermanently to each originating exchange is advantageous with respect to adantability for traffic loading and ease of regulation. The capacities of the MCNET are investigated by introducing a “traffic diffusion index” and it is concluded that the erlang capacities for the RA, DA and TA switching systems are in the ranges of some ten thousands to hundred thousands, from ten thousand to some ten thousands and from six thousand to nine thousands, respectively, and that the capacities of the transmission paths are also in erlang ranges of from 300 thousand to one million, from 200 thousand to 600 thousand and from 40 thousand to 60 thousands.
An analysis of coplanar waveguides with finite conductor thickness‐computation and measurement of characteristic impedance
Authors: Koshiji Kohji , Shu Eimei , Miki Shichiro
Published: July 2007

Computer analysis is performed for coplanar waveguides with finite conductor thickness. Such line parameters as the characteristic impedance and effective filling fraction are obtained. Experimental verification is given for the characteristic impedance.

Assuming that the line cross section is approximately symmetrical, Laplace's equation is solved by a successive over‐relaxation method for one quarter of the cross section. The characteristic impedance obtained by this approximate method is compared with that obtained by analysis of one half of the cross section with rigorous symmetry and the difference is found to be less than 0.27%. Experimental verification of the characteristic impedance is conducted by correcting the discontinuity between the measurement setup and the line to be measured. The difference between the analytical and experimental results is less than 10%. Approximate analysis by the present method is thus sufficiently accurate. The size of the storage locations in the computer is reduced and the processing time is shortened.
A stable narrow band‐pass quartz crystal filter at 150‐MHz region
Authors: Sawamoto Kenichi , Kojima Hiroshi , Hirama Koichi , Kameyama Korenori
Published: July 2007

Research on a stable narrowband quartz crystal filter at 150‐MHz band is presented. The design is based on the operational parameter method for low device sensitivity. The three‐section Wagner type circuit is realized by a symmetric lattice circuit and imaginary gyrator and in the present treatment the circuit elements of the series‐parallel branches of the symmetric lattice circuit replace the corresponding crystal resonators. The crystal resonators are AT cut and operate in the 5‐th overtone mode with thickness above 50 μm. A thin‐wafer polishing technique and adjustment method is employed. The resonator has a resonance frequency temperature coefficient of 0.2 ppm/°C, aging coefficient about −6 ppm/decade (days) and its equivalent resistance change with respect to temperature and aging is small.

The passband attenuation (finite loss) change with respect to temperature depends on the temperature characteristics of circuit components other than the resonators. By suitable selection of these components, the attenuation variation is about 0.1 dB in the temperature range of 0 to 50°C. The passband width is about 10 KHz and, as calculations show, depends on the resonator characteristics. The stopband attenuation is above 60 dB in the band of f0 ± 100 kHz, where f0 is the center frequency of the pass‐band and no spurious mode is observed. As the crystal resonators have stable temperature‐aging characteristics, long‐term stable operation is anticipated.
Heterodyne detection of partially coherent optical signal
Authors: Takenaka Takashi , Saga Nobuhiro , Fukumitsu Otozo
Published: July 2007

The SN ratio is studied for heterodyne detection of partially coherent plane wave optical signals when they are focused by a lens after passing through a circular aperture and are added to a coherent Gaussian beam local oscillator signal. We treat the case in which the intensity distribution of the signal over the aperture is uniform and the natural logarithm of its spatial coherence is expressed as the vth power of the distance between two arbitrary points on the aperture. Using a two‐dimensional Fourier transform, we express the mutual coherence function of the signal on the detector surface in a series form. The results are used to present an expression for the SN ratio suitable for numerical calculations. The SN ratio is investigated numerically with the correlation length on the aperture and the detector radius as parameters. It is found that, regardless of the correlation length, the detector radius of the order of the Airy disk is sufficient for obtaining an SN ratio almost equal to the maximum value determined for each correlation length. We also find that the maximum SN ratio is approached in the case of partially coherent signals if we use the optimum beam parameter of local oscillator signals, which has already been determined.
Chaos in a manifold piecewise linear system
Authors: Saito Toshimichi , Fujita Hiroichi
Published: July 2007

This paper describes the irregular behavior of solutions to certain differential equations. This phenomenon is called chaos and in ordinary automomous differential equations it occurs beyond three dimensions when represented by normal type. The authors propose here a new differential equation, called the manifold piecewise linear system, in dealing with this phenomenon. The equation is described by special coupling of the linear system and, from the local solution rigorously obtained, a Poincaré map for investigation of the solution behaviors is calculated rigorously. Thus, an analytical approach to the chaos of differential equations which cannot be dealt with at the present becomes possible. The differential equation solution is shown in a certain parameter region to become aperiodic and is neither convergent nor divergent. This equation can be analyzed as a whole by the Poincaré map in terms of the different parameters with the same form. This is desirable for sensitivity analysis. Also, for a given parameter and region of definition, Poincaré maps are expressed in terms of different forms and an example corresponding to previous research is presented.
Bending loss formulas for step‐index optical fiber and their applicable regions
Authors: Kusano Kiyonobu , Nishida Shigeo
Published: July 2007

This paper presents a method for analyzing bending loss formula for the hybrid mode propagating in a uniform bend. As a hybrid mode, we chose the LP mode and found dependency of the bending loss formula on the directional angle, propagation constant and the amplitude ratio and phase difference of the constituent mode. The results contain those previously obtained and are applicable to more cases. We found that the bending loss of a general LP mode depends on the amplitude ratio and phase difference of the constituent mode, the directional angle, and the propagation constant. A linearly polarized LP mode has its bending loss dependent on the directional angle but not on the polarization angle. The bending loss of the HE and EH modes does not depend on the directional angle. Based on the condition for which the deviation of the field distribution due to the bend is negligible, we found the applicable range of the bending loss formula.
Micro fresnel lenses fabricated by electron‐beam lithography
Authors: Fujita Teruo , Nishihara Hiroshi , Koyama Jiro
Published: July 2007

Microlenses constitute an area of very important components in microoptics. This paper proposes the use of electron‐beam lithography for making micro Fresnel lenses. An electron‐bean machine developed for this purpose offers great flexibility in their design and fabrication. Micro Fresnel lenses for visible and infrared were made using PMMA as an electron‐beam resist. Fabricated lenses with F‐numbers above 1 can focus incident plane waves into a nearly ideal diffraction‐limited spot with an efficiency of 30%, while theory predicts 40%. A minimum spot size, or intensity half‐width, of 0.7 μm was obtained at wavelength of 0.6328 μm using an electron‐beam fabricated lens with a very small F‐number of 0.65.
A composite gate structure for enhanced‐performance power MOS FET'S
Authors: Yoshida Isao , Okabe Takeaki , Hashimoto Norikazu , Nagata Minoru , Ochi Shikayuki
Published: July 2007

A new composite gate structure is proposed to reduce the power MOS FET ON‐resistance (loss). This gate structure consists of inhomogeneous gate oxides in an E/D gate, with a thin oxide in the enhancement gate region and a thick oxide in the depletion gate region. The structure is optimized by a 2‐dimension computer analysis. The optimum composite gate is realized with two silicon‐gate layers.

The performance of the fabricated composite‐gate power MOS FET is better than that of the conventional device for the same breakdown voltage (250 V); the ON‐resistance is only one‐half and the transcon‐ductance is four times that of the conventional device.

The proposed composite‐gate techniques are important for short‐channeling and relaxation in MOS FET and they can be applied not only to power MOS FET, but also to all MOS FET to yield higher performance.
Stability theory and existence of periodic solutions of time delayed compartmental systems
Authors: Maeda Hajime , Kodama Shinzo , Konishi Tomohisa
Published: July 2007

This paper discusses the global asymptotic stability and existence of periodic solutions of periodically varying nonlinear compartmental systems with time delay. We exploit the inherent property that any bounded solution approaches a periodic solution. Based on this result, we derive a necessary and sufficient condition for a homogeneous (zero‐input) system to be globally asymptotically stable and derive a necessary and sufficient condition for the system forced by a periodic input to admit a periodic solution. These conditions do not include time delay and are stated in terms of the interconnections among compartments. This amounts to showing that such qualitative properties of solutions are preserved irrespective of the introduction of arbitrary time delay.
Reduction method of calculating high‐order volterra functionals
Authors: Ichikawa Satoshi , Tokoro Setsuo , Kawasaki Shuji , Hagihara Satoshi , Higawara Tetsuya
Published: July 2007

A well‐known analytical method for linear systems is that which employs the Laplace transformation. Such method is applicable to analytical nonlinear systems in various ways, as has already been reported [1, 2]. A problem in this method is calculation of the multidimensional inverse transformation, which is normally performed after reduction to one dimension. However, if higher‐order terms have to be taken into account, the amount of calculation for the reduction becomes excessive, so that manual calculation is impossible. Thus, in this report we propose to achieve the reduction operation by computer. Algorithms derived are practical for application to systems that consist of the sum and product of linear subsystems, cascade connection, and feedback. These are quite efficient algorithms, fully utilizing the system characteristics. We show that the advantage of the algorithm is to have the output in the form of frequency components.
Surface acoustic wave parametric oscillation in Si/LiNbo3 substrate
Authors: Nakagawa Yasuhiko , Wakuda Mutsuo , Kobayashi Kenichi
Published: July 2007

Surface acoustic wave parametric oscillation due to the backward nonlinear process in a surface acoustic wave convolver is an interesting phenomenon and various applications have been considered. This paper discusses the theory and experimental results with a SAW reflector design with a low oscillation threshold, using a Si/LiNbO3 substrate, which yields the highest convolution efficiency. The results show that the oscillation threshold power can be greatly reduced by using reflectors (threshold power is reduced to 1/30 for a reflection coefficient of 0.75, as compared with the reflectionless case). In the experiment oscillation could be achieved with such low input power that the oscillation threshold was only 14.4 dBm, and thus SAW parametric oscillation is possible. Also, the experimental oscillation characteristics agree well with theory.
Adjoint network approach to sensitivity calculation for switched‐capacitor networks
Authors: Kunieda Hiroaki , Kaneko Mineo , Onoda Mahoki
Published: July 2007

This paper introduces a computer analytical technique for obtaining the element sensitivities of switched‐capacitor networks (SC networks) with good efficiency by using adjoint networks similar to those for conventional linear networks. The SC networks treated here consist of capacitors, ideal two‐mode switches and operational amplifiers represented by nullator‐norator models. The network equations for the SC networks with amount of charge movement and voltage as variables are so formulated that the network equations of the adjoint networks can be obtained by a simple transformation such as the transpose of their coefficient matrices and with minimum order in many cases. It is also shown that by using Tellegen's theorem in the SC networks, the element sensitivities for capacitors can be obtained as the product of the amount of charge movement in the original SC networks and the voltages in their adjoint networks. Therefore, the element sensitivities can be determined by network analysis of the SC networks and their adjoint networks and the analysis can be performed efficiently with the abovementioned formulation of network equations. Finally, an example of sensitivity analysis by implementing a computer program is shown and its effectiveness is confirmed.
Analysis and applications of new I2L multivalued logic circuits
Authors: Taniguchi Kazutaka , Inoue Takahiro , Ueno Fumio
Published: July 2007

MIN/MAX and Literal/Successor circuits are proposed which can perform two different operations at the same time. Furthermore, these circuits have fewer elements than conventional circuits. Therefore, they contribute to increasing the applicability of I2L logic circuits. New multivalued I2L D latches are also proposed, which reduce the number of elements. Their sensitivities are estimated and the relative errors in output and effective threshold are evaluated in the presence of errors in the current mirror gain and in the designed current threshold values. Operation and experimental results are described for a 3‐valued full adder and a 4‐valued D flipflop circuit.
A method of automatic image reconstruction from holograms by a homomorphic system of logarithmic transform type
Authors: Aoki Yoshinao , Kuniyoshi Toshiharu , Amber Handoko , Takahashi Yukinobu
Published: July 2007

A new computer technique for automatic image reconstruction from holograms is proposed. The technique is based on the idea of filtering in a homomorphic system of the logarithmic‐transform type. The theoretical analysis and computer simulation were conducted using the proposed technique. The technique is based on the principle that the odd function of the phase term of the Fourier transform of a real‐number function representing an object can be separated from the even function of the phase term of the propagation function representing the wave propagation. Accordingly, in the proposed method of image reconstruction the image plane can be determined automatically with only the given hologram data, even if information on the distance parameter is not obtained in the holo‐gram recording stage. To simulate the proposed technique on a computer, data of a Fresnel‐transformed hologram of complex number were generated numerically, with the assumption that a plane object is illuminated by a plane wave and image reconstruction was conducted by separating the even function of the phase term of the object function from the propagation function to demonstrate the validity of the proposed method. The possibility of automatic image reconstruction and problems of the proposed technique are discussed and the conventional method is compared with the result of the computer simulation.
Deep heating technique for hyperthermia
Authors: Amemiya Yoshifumi , Terada Noriyoshi
Published: July 2007

The heating of cancers, which are located far below the body surface, results in unwanted heating of the body surface. At 1000 MHz the penetration depth of the microwave power is 2 cm, and a strong cooling of the body surface is required while heating the deep cancer. This paper proposes an arrangement of electric current sources which permits a local heating deep in the human body and for which the heating potential and the electric field distribution in the body have been calculated. This method avoids the strong cooling of the body surface, and the electric power, which is required theoretically, is found to be reasonable.
B lymphocyte deficiency in IgH‐transgenic rabbits
Authors: Jasper Paul J. , Rhee Ki‐Jong , Kalis Susan L. , Sethupathi Periannan , Yam Pi‐Chen , Zhai Shi‐Kang , Knight Katherine L.
Published: July 2007

We developed IgH‐transgenic rabbits carrying a productive VDJ‐Cμ Tg and found the rabbits were B cell‐deficient, with a 50–100% reduction in serum IgM and IgG levels. The bone marrow of newborn Tg rabbits contained severely reduced levels of preB cells and almost no B cells. The few preB cells present in the bone marrow were large, cycling cells that expressed the VDJ‐Cμ Tg, indicating that the block in B cell development likely occurred at or before the transition from large (early) preB to small (late) preB cells. By immunoprecipitation, the Tg μ‐chain paired with VpreB and λ5, suggesting that the B cell deficiency is not due to an inability to form a preB cell receptor. Despite the block in B cell development, a few B cells, expressing predominantly endogenous μ‐chains, began the second stage of development in GALT. B cells were localized in and beneath the follicle‐associated epithelium of GALT prior to B cell follicle formation, suggesting to us that B cell follicle formation is initiated near the follicle‐associated epithelium, possibly through contact with intestinal microbiota. These IgH‐Tg rabbits should provide a useful model for studies of B cell development both in bone marrow and in GALT.
Proliferative activation up‐regulates expression of CD4 and HIV‐1 co‐receptors on NK cells and induces their infection with HIV‐1
Authors: Harada Hideki , Goto Yumi , Ohno Tadao , Suzu Shinya , Okada Seiji
Published: July 2007

NK cells play important roles in immune surveillance against malignancy and virus‐infected cells. NK cell functions are affected in patients infected with HIV‐1; however, whether there is direct interaction between NK cells and HIV‐1 remains controversial. In this study the expression of CD4, an important receptor for HIV‐1, was up‐regulated on NK cells co‐cultured with an NK cell‐selective stimulating cell line, HFWT, and rIL‐2. Although the level of CD4 was lower on NK cells than on CD4+ T cells, expression of the HIV‐1 co‐receptor CCR5 was clearly up‐regulated on CD4+ NK cells. CD4+ NK cells expressed higher levels of HLA‐DR and CD25 than CD4– NK cells, suggesting that they were highly activated. Cell‐free HIV‐1 could not infect the NK cells, but NK cells were infected when co‐cultured with HIV‐1‐infected T cells. Using this co‐culture system, we can better understand how HIV‐1 infects NK cells and how NK cell functions are affected in AIDS.
Syntheses, Characterization, and Luminescent Properties of Monoethylzinc Complexes with Anilido–Imine Ligands
Authors: Su Qing , Gao Wei , Wu Qiao‐Lin , Ye Ling , Li Guang‐Hua , Mu Ying
Published: July 2007

The syntheses of three anilido–imine ligands of the general formula ortho‐C6H4(NHAr′)(CH=NAr″ [Ar′ = 7‐(2,4‐Me2)C9H4N, Ar″ = 2,6‐Me2C6H3 (2a); Ar′ = 7‐(2,4‐Me2)C9H4N, Ar″= 2,6‐Et2C6H3 (2b); Ar′ = 7‐(2,4‐Me2)C9H4N, Ar″= 2,6‐iPr2C6H3 (2c)] and four zinc(II) complexes of the general formula [ortho‐C6H4(NHAr′)(CH=NAr″)]ZnEt [Ar′ = 7‐(2,4‐Me2)C9H4N, Ar″= 2,6‐Me2C6H3 (3a); Ar′ = 7‐(2,4‐Me2)C9H4N, Ar″= 2,6‐Et2C6H3 (3b); Ar′ = 7‐(2,4‐Me2)C9H4N, Ar″ = 2,6‐iPr2C6H3 (3c); Ar″ = 2,6‐Me2C6H3, Ar″ = 2,6‐iPr2C6H3 (3d)] are described. The complexes were synthesized from the reaction of ZnEt2 with corresponding ligands 2 by alkane elimination. All compounds were characterized by elemental analysis and 1H and 13C NMR spectroscopy. The molecular structures of compounds 2a, 2b, 3b, and 3c were determined by single‐crystal X‐ray crystallography. The X‐ray analysis reveals that complexes 3b and 3c exist in the dimeric form with the N atom in the quinolyl ring coordinating to the other Zn atom to make the Zn atoms four coordinate. Luminescent properties of ligands 2a–2d and complexes 3a–3d in both solution and the solid state were studied. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
An Approach to the Synthesis of Silicon Carbide Nanowires by Simple Thermal Evaporation of Ferrocene onto Silicon Wafers
Authors: Niu Jun‐Jie , Wang Jian‐Nong
Published: July 2007

Scales of silicon carbide nanowires (SiC‐NWs) with high quality were synthesized by direct thermal evaporation of ferrocene onto silicon wafers at high temperature. Ferrocene decomposed into iron and carbon, which was subsequently treated with silicon to form SiC‐NWs at high temperature. The SiC‐NWs possess small diameters of ≈ 20 nm and lengths of several μms. Furthermore, the samples show a uniform morphology, crystalline structure, and a very thin oxide layer. The main crystal direction of [111] was confirmed by high‐resolution field‐emission‐transmission electron microscopy (HR‐FETEM). The Raman scattering spectra showed two peaks at ≈ 796 (TO) and ≈ 980 cm–1 (LO) with varying intensity ratios at different positions. The band line fluctuation was contributed to the Raman selection rules. With reference to the experimental results, we suggested a tentative growth model according to the vapor–liquid–solid (VLS) mechanism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Facile Synthesis of Aluminum‐Bridged [3,3,3]Cyclophanes by Hydroalumination
Authors: Uhl Werner , Hepp Alexander , Matar Madhat , Vinogradov Andrej
Published: July 2007

The reaction of 1,3,5‐tris(3,3‐dimethyl‐1‐butinyl)benzene C6H3(C≡C–CMe3)3 with the dialkylaluminum hydrides HAl(CMe3)2 and HAl(CH2CMe3)2 gave the addition of one Al–H bond to each C–C triple bond (hydroalumination). Spontaneous condensation by the release of the corresponding trialkylaluminum derivatives afforded [3,3,3]cyclophane derivatives 6 and 7 in which three tricoordinate Al atoms are in the bridging positions between two functionalized benzene rings. The aluminum atoms behave as Lewis acids, and treatment with thf yielded adduct 6·3thf. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Proton NMR Study of Low‐Spin meso‐Unsubstituted β‐Substituted Alkyl Iron Porphyrins: Remarkable Influence of Peripheral Substitution on Spin Density
Authors: Juillard Sandrine , Bondon Arnaud , Simonneaux Gérard
Published: July 2007

Paramagnetic NMR spectroscopy was used to characterize the influence of small alkyl groups on the spin density of a series of high‐spin and low‐spin iron(III) porphyrins. Assignment of the resonances was obtained by using a variety of NMR techniques including heteronuclear multiple bond correlation and saturation transfer experiments. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Tetranuclear (Phosphane)(thiolato)gold(I) Complexes: Synthesis, Characterization and Photoluminescent Properties
Authors: Fernández Eduardo J. , Laguna Antonio , López‐de‐Luzuriaga José M. , Monge Miguel , Montiel Manuel , Olmos M. Elena , Puelles Raquel C. , Sánchez‐Forcada Eva
Published: July 2007

The reactions of the tetraphosphane donor ligand (Ph2PCH2)2NCH2CH2N(CH2PPh2)2 with the gold precursors [AuCl(tht)] or [Au(C6F5)(tht)] (tht = tetrahydrothiophene) leads to complexes [Au4R4{(Ph2PCH2)2NCH2CH2N(CH2PPh2)2}] [R = Cl (1) or C6F5 (2)]. Further substitution of the chlorine atoms in 1 by the corresponding 4‐substituted benzenethiolates gives rise to the tetranuclear (phosphane)(thiolato)gold(I) complexes [Au4(S‐C6H4‐X)4{(Ph2PCH2)2NCH2CH2N(CH2PPh2)2}] [X = F (3), MeO (4), Me (5) and NO2 (6)]. Complexes 2 and 4 were characterized by X‐ray diffraction studies showing Au···Au interactions in the case of complex 4. Complexes 3–6 display intense emissions in the solid state at 77 K with lifetimes in the microsecond range. The observed phosphorescent emissions are attributed to metal‐to‐ligand charge‐transfer transitions. Nevertheless, the influence in the emission energies of gold–gold interactions or the contribution of the substituent in the 4‐position of the benzenethiolate ring to the excited state cannot be neglected. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A new pst‐weighting filter for the flickermeter in the frequency domain
Authors: Amarís H. , Usaola J.
Published: July 2007

This paper presents a new filter for the Flickermeter in the frequency domain that allows a fast estimation of the Pstshort‐time flicker parameter. The power spectrum of the signal is weighted with the new Pst‐weighting filter and the Pstparameter may be deduced directly. The Flickermeter structure has been tested with the IEC‐Flickermeter recommendations and it presents a good behaviour in the whole bandwidth of O Hz to 35 Hz even in very low frequencies. The filter model has been deduced by using identification tools in the frequency domain. The advantages of the Flickermeter methodology in the frequency domain are studied.
Design of current and speed controllers for slip energy recovery induction motor drive using root‐locus technique
Authors: Faiz J. , Barati H. , Akpinar E.
Published: July 2007

The most common problem of the slip recovery system is stabilizing the system under power system disturbances, such as the change of supply voltage. Two back‐to‐back proportional‐plus‐integral (PI) controllers are used in a closed‐loop control system, to control the DC‐link current and speed. In order to estimate parameters of the controllers using root‐locus technique, a non‐linear transient model of the drive is linearized around the steady‐state operating point. The performance of the drive in the presence of disturbance signals is studied and finally the eliminating speed error signal and the continuous variations of the inverter‐firing angle are illustrated.
Research note: Dielectric diagnosis of water content in transformer insulation systems
Authors: Küchler A. , Bedel T.
Published: July 2007

This paper describes dielectric measurements at transformer insulation models made of Transformerboard barriers and oil channels. It was intended to quantify the water content in barriers and to distinguish the influences of water and geometric structure. Recovery‐voltage measurements (RVM) did not show a clear correlation with water content, probably because of “parasitic” influences like oil parameters, geometry and parallel resistances. Better correlations were found for insulation resistances i. e. for polarization currents. Network simulations show that common circuits ‐ normally used for homogeneous materials ‐ are not able to explain the measurements. Therefore circuits had to be adapted to the geometric structures of the insulation. Thereby it could be shown that recovery voltages are dominated by interfacial polarisation between oil channels and barriers. Signals are strongly dependent on oil resistivities, possibly “masking” the influence of water in the barriers.
Enhanced ac power‐flow solutions for reliability analyses
Authors: Sorg A. , Heckmann W. , Weber Th. , Wellssow W. H.
Published: July 2007

The paper presents an advanced Newton‐Raphson power‐flow algorithm for reliability evaluation with special regard to the prevention of non‐convergent situations. Remedial actions in order to relieve violations of operational constraints and some generation rescheduling functions are considered. Included is a reliability analysis for a sample power system in order to compare the resulting reliability indices using different power‐flow algorithms.