摘要:

AbstractThe prism coupler has long been used for excitations of Rayleigh and Lamb waves. Since analysis is lacking in the leaky wave phenomenon on the guided wave path due to the prism perturbation, many problems are not explained. In this paper, the solid and liquid prism couplers are analyzed by the leaky wave concept and modeconversion theory, the following problems are clarified: the mode conversion efficiency expected to be obtained in theory, the coupling length between the prism and the guided wave path as related to the mode‐conversion efficiency, the difference between the p‐ and sv‐wave in the solid prism coupler, the effect of the liquid couplant, and the effect of the absorption loss in the prism material. Three of the universal diagrams are also provided. It is confirmed that the measured and theoretical available conversion efficiency for the Rayleigh wave transducer consisting of the bulk wave transducer are in good agre

ISSN:8756-6621    

DOI:10.1002/ecja.4400630202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper investigates the properties of reachable sets of discrete‐time compartmental systems. The discrete‐time compartmental system is characterized by the non‐negativeness of all coefficients of its system state equations and its inputs.The paper first deals with the properties of reachable sets at finite sampling times of general ordinary linear discrete‐time systems with simple non‐negative input, and the n.a.s.c. under which the reachable set coincides with the maximal reachable set at finite sampling times. Then, it deals with the characteristic polynomial representation of state transition matrix and the properties of the maximal reachable set. After showing the properties of reachable sets of compartmental systems, the paper discusses the drug kinetics problem as an example of the analysis of reach

ISSN:8756-6621    

DOI:10.1002/ecja.4400630203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

Abstract“Decomposition into independent line groups” is usually possible for multi‐conductor transmission lines in case the product of the per‐unit‐length impedance (z) and admittance (y) matrices, for uniform lines L can be diagonalized. Some reports have suggested that L could be “practically” decomposed into independent line groups just as the F‐matrix is decomposed by the “quasi‐real ideal transformer networks” (QRITN) P‐1 + tp. Here, P is a similarity transformation matrix that diagonalizeszy; + denotes the direct sum of the matrices, andtX is the transpose of X. This paper points out that some points in decomposition theory for transmission lines remain to be studied; these points are further examined by the author. First, the L decomposition theory is also applied to the ease when bothZandyare symmetric and non‐singular and the productz yis not necessarily diagonalizable. As a result, it is demonstrated that L can in general be decomposed by the QRITN into a set consisting of a few independent transmission lines. Second, a computer method for calculating a decomposition matrix for L is introduced, together with the L's F‐matrix. The method is a natural generalization of the conventional procedure for computing the L decomposition matrix and is only applicable in case no multiple eigenvalues exist. Finally, the author proposes a new method for computing the “referencezymatrix”, even for non‐uniform lines, a

ISSN:8756-6621    

DOI:10.1002/ecja.4400630204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractTree codes are so important that they often appear in information theory. Highly reliable coding systems may be realized in view of their sequential decoding. While a number of analyses have been made of the probability of error in sequential decoding and of the amount of calculation required for decoding only a few analyses are presently available on the various characteristics when sequential decoding is applied to convolutional codes. Here, we shall evaluate the so‐called deficient decoding that occurs when convolutional codes are sequentially decoded by decoders with finite decoding speeds. The evaluation will be based on the findings of recent studies on the amount of calculation required for the sequential convolutional code

ISSN:8756-6621    

DOI:10.1002/ecja.4400630205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractFor transmitting distortionless arbitrary waveforms over set‐ups with different impedances, the nonuniform lines have been used for a long time by wide‐band impedance‐transform and matching. But rigorous theory is still lacking in treating the basic problems concerning the relationship between the distortionless waveform and the nonuniform line distribution, i.e., the distortionless conditions or the impedance‐matching conditions for the nonuniform lines. This paper first investigates the voltage/current transfer‐functions over any line interval and the local propagation constant. It is then clarified that there exist on the one‐dimensional nonuniform line essentially six localized distortionless conditions for the voltage/current waveforms. Next, the distortionless wave quantities and characteristics, the finitely long line analysis, as well as method of excitation (matching) of the distortionless wave, are presented. Finally, it is shown that all‐pass impedance transformer, attenuator and phase shifter can be realized by using the distor

ISSN:8756-6621    

DOI:10.1002/ecja.4400630206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe grounded monopole antenna without earthing used as a basic ground antenna is analyzed by the moment method. Its current distribution, input impedance, directivity and antenna efficiency as functions of earth dielectric constant and conductivity, antenna height and frequency are obtained. The generalized impedance can be made calculable even for the case of nonzero current at the end of the antenna. Numerical results show that the current distribution varies subtly with the earth electrical properties. The small‐area effect of earth is clarified. For the quarter‐wave monopole antenna, the efficiency increases with decreasing frequency but it is below 50% for typical earth conditions when the frequency is above 0.1 MHz. For large antenna height, the antenna efficiency is large, the maximum directivity becomes closer to the horizon, but at 0.6 wavelength the radiation along the sky direction is strong, and the fact that at 0.53 wavelength it is used as an end‐firing antenna can be explained. It is shown that the antenna efficiency becomes lowest when the earth displacement and conduction currents are

ISSN:8756-6621    

DOI:10.1002/ecja.4400630207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractIn general, in the problem of directivity synthesis, the objective function for optimizing the gain and conditions for constraining the fields of the sidelobe levels must be taken into account together. These kinds of problems had been solved by the so‐called quadratic programming method among other mathematical programming methods, but when the element number becomes large, so must the sidelobe constraint condition number. Thus this method becomes rather difficult in practice.In this paper such a directivity synthesis problem will be formulated as an optimization problem in which Lagrange multipliers will be employed for the objective function which is in quadratic form. Thus, the problem will be solved approximately by introducing Lemez' best‐approximation concept; the solutions will be obtained by use of an extremely simple and rapidly converging iteration‐numerical approach.Although this approach may occasionally yield solutions which are not optimized, its results will be sufficiently close to the optimized solution that it is a practical one. Since, especially, the iteration calculations can be attained by merely considering simultaneous equations, as a computer‐oriented method, this approach can yield solutions more rapidly than the quadratic programming method for a large number of e

ISSN:8756-6621    

DOI:10.1002/ecja.4400630208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe axial‐mode helical antennas with finitely large reflectors radiate sharp, circularly polarized beams along the antenna axis when the circumference of the helix is about one wavelength long and the pitch angle is 12° ∼ 14°. Although experimental results and approximate theories have been reported, no detailed theory has ever appeared. This paper discusses the radiation characteristics of the axial‐mode helical antenna with the reflector both theoretically and experimentally. First, assuming the reflector is infinite in size, we solve an integral equation satisfying the boundary conditions and obtain the current distributions on the antenna. Characteristics have been studied even for the case with a large number of turns. Next, using the current distribution thus obtained, we find the current distributions on the reflector. By means of the induced emf method, we analyze the radiation characteristics (directivity, power gain and axial ratio) of the axial‐mode helical antenna. Further, we confirmed the analysis exper

ISSN:8756-6621    

DOI:10.1002/ecja.4400630209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractSoft errors of the bipolar RAM (Random Access Memory) caused by α particles emitted from the radioactive material in the package are investigated. The in‐system test and the particle irradiation test were performed by using a 1 Kbit RAM made especially for this purpose. The relation between the soft error rate and the amount of the α particle irradiation was examined. It was confirmed that even in the static bipolar RAM, soft errors do occur due to α particles from the package. The relation between the soft error rate, memory cell structure and the design condition was discussed. Furthermore, the mechanism of soft errors was investigated and the soft error rate was estimated by considering the effective noise change due to α particles and the charge required to invert data in the flip‐flop cell. These results were compared with the exp

ISSN:8756-6621    

DOI:10.1002/ecja.4400630210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThis paper describes a contactless method for measuring sheet conductivity and mobility of the semiconductor wafer. In comparison with the conventional 4‐probe and van der Pauw methods, no ohmic contacts are needed and therefore no nondestructive measurement error exists. Previously, the quantitative relations of the conductivity and mobility with the distributions of eddy current to be measured and Hall voltage, as well as the voltage for eddy current detection were not clear. In this paper, by considering the mutual inductances between the coil and wafer, these have been clarified. The proposed theory and experimental results are compared and their agreement confirmed. The dependence of the voltage for eddy current detection on frequency is also investigated and optimum frequency for measurement derived. The equivalent circuit is used for Hall voltage detection. Optimized electrode dimensions are shown to exist for maximizing the detection voltage and are verified by experiment. Consequently, this method enables absolute measurements and, concerning the mobility measurement, it has clarified the relationship between the measurement sensitivity and resolving powe

ISSN:8756-6621    

DOI:10.1002/ecja.4400630211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY