result 1627 件
| JaLCDOI | 10.18926/15774 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_18_1_91.pdf |
| Author | Sano, Hiroya| Koga, Ryuji| Kosaka, Megumi| Wake, Ichiro| |
| Abstract | This paper presents an optical-waveform synthesizer as one of the applications of optical bistable devices. This device is advantageous in terms of faster operation in which width of each pulse obtained is down to the order of subnanosecond, because this device employs both GaAs- and Si-optoelectronic switches as photodetector. Optical pulse shaping as a preliminary experiment is also described. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1984-03-30 |
| Volume | volume18 |
| Issue | issue1 |
| Start Page | 91 |
| End Page | 100 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307204 |
| JaLCDOI | 10.18926/15763 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_15_1_101.pdf |
| Author | Taniguchi Takeo| Numata Katsu| |
| Abstract | In this paper the fill-in minimization problem which arises at the application of the sparse matrix method for a large sparse set of linear equations is discussed from the graph-theoretic viewpoint and also through the numerical experiments. Therefore, this investigation consists of two parts, and in the former part the author shows, at first, that the elimination process of a sparse matrix is equivalently replaced to the vertex eliminations for a graph obtained from the matrix, and by use of some concepts in the theory of graph he proves that the vertex elimination process for the minimum fill-in is equivalent to the vertex eliminations for vertices in each subgraph which is obtained by the appropriate dissection of whole graph, and that there are only two types of vertex eliminations through the process. This results in the proposal of a new model of the vertex elimination process. The latter part of this investigation is used for the verification of the results from the theoretic investigation. Through the numerical experiments he concludes that the new model of the vertex elimination process is valid, at least, for a graph like a regular finite element mesh. Furthermore, he shows that this model coincides with Nested Dissection Method which can give the minimum value of fill-in, at present. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1980-11-29 |
| Volume | volume15 |
| Issue | issue1 |
| Start Page | 101 |
| End Page | 110 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307966 |
| JaLCDOI | 10.18926/15761 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_15_1_79.pdf |
| Author | Morikawa, Yoshitaka| Hamada, Hiroshi| |
| Abstract | Two variational formulations for electromagnetic field and charged-particle stream configurations, in which both field and particles are described by the field-like variables suited for the problems of electrodynamics, are presented. One of them is directly obtained through slight modifications of Sturrock's original procedure but has a complicated form. The other is obtained through linearization of the preceding one and has a compact form. Both formulations lend themselves to straightforward derivation of the well-known energy-momentum tensor and/or its conservation law. Specifically the latter one is of academic interest because of its compact form. Moreover, as a proof of its practical usefulness the variational principle under the small-amplitude approximation is derived from it, which is known to provide a basis for the study of certain types of instability in plasmas. It is, however, hoped that it will find main applications in the electrodynamics problems concerned with large-amplitude behavior. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1980-11-29 |
| Volume | volume15 |
| Issue | issue1 |
| Start Page | 79 |
| End Page | 100 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307937 |
| JaLCDOI | 10.18926/15742 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_14_1_61.pdf |
| Author | Kono Iichiro| Nishigaki Makoto| |
| Abstract | The purposes of this paper are primarily to research on behavior of groundwater flow in saturated and unsaturated zone and to develop the most effective methods for solving groundwater flow problems related to civil engineering practice. The mathematical model provides a finite element solution to two- or threedimensional problems involving transient flow in the saturated and unsaturated domains of nonhomogeneous, anisotropic porous media. Before progressing into the various levels of applications the input data and boundary conditions are discussed and evaluated. To demonstrate the flexibility of the finite element approach and its capability in treating complex situations which are often encountered in the field, the groundwater flow through sand bank at flood water levels and the flow through aquifer due to an excavation were analyzed. As the results there were good qualitative agreements between the numerical results and the informations received. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-12-01 |
| Volume | volume14 |
| Issue | issue1 |
| Start Page | 61 |
| End Page | 94 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307580 |
| JaLCDOI | 10.18926/15735 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_14_1_9.pdf |
| Author | Fujiwara Yasuo| Monobe Kazuo| |
| Abstract | In the course of the study of polymer crystallization at high pressure, oriented crystallization of extended chain crystals of polyethylene were examined. Molten polyethylene were extruded into a die at a few hundred atm, and follwed by crystallization by high pressure application above 3000 atm. Resulting sample shows chain orientation to extruded direction. Thick lamella nearly a few thousand angstrom, which are typical feature of high pressure crystallization, were observed to be stacked parallel each other. In spite of favorable condition for crystals to grow to chain direction, remarkable growth to normal direction to them were also observed. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-12-01 |
| Volume | volume14 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 14 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307317 |
| JaLCDOI | 10.18926/15729 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_13_239.pdf |
| Author | Taniguchi Takeo| |
| Abstract | In this paper the minimum fill-in problem which arises at the application of the sparse matrix method for linear sparse systems is discussed from the graphtheoretic viewpoint and the author gives some results which can be directly introduced in the design of, so called, the optimal elimination ordering algorithm which gives the minimum fill-in(the number of zeros in coefficient matrix which become non-zero during the elimination process). Through this investigation only graphs are treated instead of the coefficient matrices for linear systems, and the elimination process for a matrix is equivalated to the vertx eliminations for the graph. Then, the results by the theoretical investigation are summarized as following: 1. Optimal elimination for each subgraph which is subdivided appropriately from whole graph leads to the global optimum. 2. In each subgraph there are only two kind of eliminations. Furthermore, some numerical experiments show the characteristics of the subset of vertices, which subdivide a subgraph from the residual. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-03-05 |
| Volume | volume13 |
| Start Page | 239 |
| End Page | 248 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307617 |
| JaLCDOI | 10.18926/15728 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_13_225.pdf |
| Author | Kaneda Masahiro| Shinji Hiroshi| Aoyama Mikio| |
| Abstract | This paper deals with the adaptive observer which estimates the states and parameters of unknown system. It is shown that the adaptive observer problem is reduced to the identification of the transformation matrix for an arbitrary designable observer. Moreover, the adaptive process of the unknown parameters is reduced to the linear optimal regulator problem. As the result, a new method is presented to obtain an appropriate adaptive process with good insight. And, in this identification, a linear filter is found to be also useful against noises in input-output data. To achieve high accuracy, a particular nonlinear filtering can improve SN ratio only in the direction of the unknown vector. Even if SN ratio of input-output data has zero dB, sufficient accuracy can be accomplished within suitable correction time. This design algorithm seems to be rather straightforward and practical. Since input sequence is required to be only sufficiently general, the method is applicable to on-line identification also. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-03-05 |
| Volume | volume13 |
| Start Page | 225 |
| End Page | 238 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307984 |
| JaLCDOI | 10.18926/15722 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_13_181.pdf |
| Author | Sano, Hiroya| Koga, Ryuji| Tanada, Yoshihiro| Kosaka, Megumi| |
| Abstract | This report deals with a notion of adjoint spectrum which is applicable to air-pollution monitoring by using pulsed lasers. Both Raman and absorption spectra of multiple gas complex are linear combinations of the spectra, each of which is specific to a gas species and its magnitude is proportional to the density. An extended formulation of the method of least squares is made in terms of a new notion, adjoint spectra, which visualizes the structure of the numerical filter. Applications of the derived numerical filters to the two methods are shown and features are described about the synthesized filters. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-03-05 |
| Volume | volume13 |
| Start Page | 181 |
| End Page | 193 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307476 |
| JaLCDOI | 10.18926/15721 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_12_53.pdf |
| Author | Fujitsuka Takeshi| Agusa Toru| |
| Abstract | In recent years, the development of a high power transistor element is proceeding. A high power inverter circuit using power transistors are finding a good number of applications in induction heating and melting. Turn off time of power transistors occupies 5-lOμs of switching characteristics. A driving method to give base inputs for a half period is widely used for a inverter circuit. But this method has the following defects, the short-circuit current flows through two transistors because the other pair transistors turn on before one pair transistors turn off. So the switching loss is increased, the maximum output and the efficiency are decreased. In this paper, a driving method to give base inputs for the less period as compared with a half period is discussed. Using this method, the foregoing defects is lost and the driving frequency is able to become higher. In addition, it become clear that the square waveform output is given using this method in the case of R-L load. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1978-02-25 |
| Volume | volume12 |
| Start Page | 53 |
| End Page | 58 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307552 |
| JaLCDOI | 10.18926/15719 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_13_163.pdf |
| Author | Tanada Yoshihiro| Sano Hiroya| |
| Abstract | A new waveform analyzer based on the Walsh transform is developed and is applied to a real-time filtering of fast pulse signals, and the linear filterings of time signals through the Walsh transform is discussed. The analyzer converts a solitary waveform during 16 μs into the 16 Walsh amplitude spectra in a hybrid manner: it has the sequency band from 62.5 kzps to 500 kzps. The spectra are parallelly held during 16 μs by analog integrators, while serially displayed by the CRT, and one of them is digitally read out. The spectra of the test waves are measured within the error rate of several per cent. The analyzer is applied to the correlative detection of the photoelectric pulse signals in a gasspectroscopic system using a pulse laser, and there composes the matched filter, which is useful for measuring the signals superposed by Gaussian noises with a high accuracy. For the real-time filtering of fast signals, the arithmetic convolution and the frequency power spectra are approximated using the complex Walsh transform. These approximations are of practical use in 16 or 32 dimensions. Then, the matched filters for pulse peaking are given by the approximate convolution and by the dyadic convolution. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-03-05 |
| Volume | volume13 |
| Start Page | 163 |
| End Page | 180 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307519 |
| JaLCDOI | 10.18926/15690 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_10_2_55.pdf |
| Author | Nakata Takayoshi| Ishihara Yoshiyuki| Matsubara Kazunori| Nakano Masanori| |
| Abstract | A new method have been developed based upon analogue-to-digital conversion techniques and memories. The method involves the scaling of operating frequency from "real" to "optimum" for the power loss measurement. The advantages of using this techniques are as follows: (1) extreme availability at lower frequency region, (2) high accuracy and high stability, (3) simple measuring procedure, (4) digital indication. This method can be measured the power losses over the frequency range 0.1Hz to 1kHz for magnetic circuit and d.c. to 1kHz in such a purely resistive circuit. We estimate the accuracy of this core loss measuring system within 1.0% over all these frequency range. Using this system, specific core losses of the various grades of silicon iron have been measured in the frequency range 0.1Hz to 200Hz. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1976-01-27 |
| Volume | volume10 |
| Issue | issue2 |
| Start Page | 55 |
| End Page | 61 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307969 |
| JaLCDOI | 10.18926/15676 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_10_1_17.pdf |
| Author | Osaki Hirokazu| Kikuchi Susumu| |
| Abstract | In multivariate analysis, the linear discriminant analysis and the test for differences between mean values of two populations are of wide application. It is not essential to increase the variables only in order to increase the degree of accuracy of discrimination or test without evaluating the effect of variables. Therefore the computer program of selection procedures of variables in these two methods is mentioned in this paper. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1975-07-01 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 17 |
| End Page | 37 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307596 |
| JaLCDOI | 10.18926/15675 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_4_65.pdf |
| Author | Himei Toyoji| Fujitsuka Takeshi| Inoue Jyunichi| |
| Abstract | As one of the wide application of thyristor circuits, the inverter has a promising future and has been investigated vigorously. On the speed control of a squirrel cage induction motor by using a variable frequency thyristor inverter, although few papers have been presented, there seems to be many problems to be solved imminently. In this paper, the stability of performance of a thyristor inverter on this theme has been confirmed and some particular points with relation to practical use also have been discussed. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1969-09-01 |
| Volume | volume4 |
| Issue | issue1 |
| Start Page | 65 |
| End Page | 73 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307309 |
| JaLCDOI | 10.18926/15664 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_9_1_23.pdf |
| Author | Misaki Takayoshi| Yamamoto Hideki| Itaka Koshi| |
| Abstract | This paper describes the spacer design for SF(6) gas insulated cables. The maximum electric stress within the cable is calculated by a numerical method, and it is recognized that the breakdown voltage depends linearly on the calculated values. Moreover, the effects of varying the shape of the spacer are made clear in this study for designing an optimum spacer. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1974-07-20 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 23 |
| End Page | 33 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307363 |
| JaLCDOI | 10.18926/15657 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_8_1_25.pdf |
| Author | Wada Tsutomu| Shimizu Akira| Takagi Minoru| |
| Abstract | The effects of some geometries peculiar to the wallattachment fluidic devices on the attaching jet flow and the switching mechanism were experimentally made clear. And the propriety of the analytical mOdel, which has been used for the theoretical study of these devices, was investigated. The results can be summarized as follows: 1) The existing analytical model of the attaching jet flow is not applicable to the case of relatively short wall length of vent distance. 2) The attaching jet flow never detaches from a sufficiently long side wall with vent. 3) The switching mechanism of the vent type device is always the opposite wall switching. 4) From the viewpoint of the output characteristics of the device, the vent distance has a lower limit in relation to the vent width. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1973-07-20 |
| Volume | volume8 |
| Issue | issue1 |
| Start Page | 25 |
| End Page | 40 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307550 |
| JaLCDOI | 10.18926/15649 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_7_1_43.pdf |
| Author | Kaneda Masahiro| |
| Abstract | This paper deals with a parameter estimation method which yields the more suitable estimate of the parameter using noisy data or measured values. The estimation method is one that uses a kind of a weighted mean, and weighting at taking a weighted mean is interested in particularly. That is to say, as the grade of 'more suitable' depends upon the weighting, we can obtain the more suitable estimate by choosing the weighting coefficients suitablly. When the function which yields the estimate using finite measured values, i.e., the estimator is a particular form, sub-optimal weighting in the practical sense is discussed. Here, the concept of 'optimal' implies that the variance of the final estimate is minimum. And the particular form is one that both the denominator and the numerator of the estimator are first order formulas or second order formulas of finite measured values. And two theorems in relation to this problem are proposed and proved. Moreover, for an exsample of application of these theorems, a parameter estimation method is dealt with, which estimates the parameters of the pulse transfer function of a control system using the sampled measured values of the impulse response of that system. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1972-07-10 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 48 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307213 |
| JaLCDOI | 10.18926/15648 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_7_1_31.pdf |
| Author | Ishii Tadao| |
| Abstract | A theory, based on Chambers' method to the classical Boltzmann equation, is developed for an acoustic amplification in both degenerate and nondegenerate piezoelectric semiconductors subjected to the Hall geometrically configured electric and magnetic fields. It is found that an amplification constant for qR>1 holds not only for a magnetic field ω(c)τ>1 but for ω(c)τ<1 under ql>1 while the amplification constant for qR<1 does for ql≦1 under ω(c)τ>1; q is the wave number vector of sound, R the cyclotron radius, ω(c) the cyclotron frequency, 1 the mean free path and τ the relaxation time. A generalized attenuation (amplification) constant is presented through an energy conservation law, being applicable to the sounds propagating at any angle with respect to the particle drift so the off-axis as well as on-axis amplifications are surely involved. An application of the present theory to n-InSb reveals a threshold dependence for the acoustic amplification, which is semi-quantitative agreement with the experimental result of Arizumi et al.. The amplification constant by that nondegenerate particles is found to be almost equal to that by the degenerate ones, provided that the former carrier density should be replaced by its three times as much. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1972-07-10 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 31 |
| End Page | 42 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307574 |
| JaLCDOI | 10.18926/15634 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_6_21.pdf |
| Author | Wada Tsutomu| Shimizu Akira| |
| Abstract | In this report, the effects of splitter position on the attached jet were experimentally investigated for the purpose of discussing the applicability of a usual mathematical model without splitter. As results, the followings were confirmed, (l) For the splitter distance shorter than the critical distance, the pressure in the bubble lowers and the jet radius of curvature shortens. (2) At the ratio L(s)/D=4~5, the switching control flow rate becomes maximum. And bordering this value, the effects of splitter position on the switching are quite conversely. For the splitter distance longer than the above value, the switching control flow rate decreases, as increasing the distance. (3) For the splitter distance of 1.5~2 times critical distance, the switching is almost never affected by the splitter. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1971-09-01 |
| Volume | volume6 |
| Issue | issue1 |
| Start Page | 21 |
| End Page | 25 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307823 |
| JaLCDOI | 10.18926/15624 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_3_157.pdf |
| Author | Misaki Takayoshi| Okamoto Takuji| Kato Osamu| |
| Abstract | In the analog circuits for the systms governed by the dilfercntial equations with the coefficients which are a function of one or mOre of the dependent variables, the magnitudes of their circuit elements must be variable in accordance with the nature of the function. Such circuit elements can be realized by means of inserting or removing the additional elements with high speed switches in the analog circuits. Particularly, in the case of varying stepwise this method is effective. But as an analog circuit is regarded as a short-time or repetitive type analyzer, the above switches must be instantaneous operation. In this paper, first, it is made sure by the experiments that some of the transistor switches arc met this condition, and moreover arc very low closed resistance, very high open resistance and neglegible small voltage offsets. Next, the basic technique for the direct analog simulation usiug transistor switches is described about the simple example, i.e. the oscillatory system with varying cross-scctional surge tank. Finally, as its applications, the transient problems of these oscillatory systems arc solved by means of these analog circuits. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1968-09-01 |
| Volume | volume3 |
| Issue | issue1 |
| Start Page | 157 |
| End Page | 162 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307953 |
| JaLCDOI | 10.18926/15569 |
|---|---|
| Title Alternative | CONCENTRATION OF RADIOACTIVE ELEMENTS IN THERMAL. WATERS BY ION EXCHANGE RESIN AND ITS APPLICATION ON ANALYSIS. |
| FullText URL | 006_025_033.pdf |
| Author | Ashizawa, Takashi| |
| Abstract | The author succeeded to concentrate Radium B, Radium C, Thorium B etc. in thermal waters of Misasa almost completely without carrier using ion exchange resin and sulfonated coal. Ion exchange resin is useful for the determination of Th B in the mineral waters. The condition of ion exchange reaction concerning lead and bismuth was investigated. |
| Publication Title | 岡山大学温泉研究所報告 |
| Published Date | 1952-03 |
| Volume | volume6 |
| Start Page | 25 |
| End Page | 33 |
| ISSN | 0369-7142 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002307922 |
