著者 Wang, Zhi Liang| Wada, Osami| Toyota, Yoshitaka| 古賀 隆治|
発行日 2002-5
出版物タイトル Electromagnetic Compatibility
資料タイプ 学術雑誌論文
著者 Wang, Zhi Liang| Wada, Osami| Toyota, Yoshitaka| 古賀 隆治|
発行日 2003-11
出版物タイトル Environmental Electromagnetics
資料タイプ 学術雑誌論文
著者 Wang, Zhi Liang| Wada, Osami| 古賀 隆治|
発行日 2003-8
出版物タイトル Electromagnetic Compatibility
1巻
資料タイプ 学術雑誌論文
JaLCDOI 10.18926/15703
フルテキストURL Mem_Sch_Eng_OU_11_1_19.pdf
著者 古賀 隆治|
抄録 An optimal control is giyen for regulating power distribution in a nuclear power reactor which has cylindrical geometry. The space dependence of the system is described by expanding space depenident variables by Helmholtz modes. Results are obtained through the principle of optimality and are described by the Riccati-type algebraic equation that the optimal feedback coefficients should satisfy. Use of an integral equation as the system equation makes it possible to deal with actual controlling apparatuses: control rods or rod clusters.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1976-07-20
11巻
1号
開始ページ 19
終了ページ 30
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307572
JaLCDOI 10.18926/15722
フルテキストURL Mem_Sch_Eng_OU_13_181.pdf
著者 Sano, Hiroya| 古賀 隆治| Tanada, Yoshihiro| Kosaka, Megumi|
抄録 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.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-03-05
13巻
開始ページ 181
終了ページ 193
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307476
JaLCDOI 10.18926/15723
フルテキストURL Mem_Sch_Eng_OU_13_195.pdf
著者 Sano, Hiroya| 古賀 隆治| Tanada Yoshihiro| Kosaka, Megumi|
抄録 The maximally attainable accuracy of an airpollution monitoring system is investigated. The system is composed of a tunable pulsed dye laser as the light source, photodiodes as the opto-electric converter and a low noise electronic signal processor specifically designed by the authors. The extreme value of the accuracy is given in terms of the standard deviation of the attenuation. The value is 3.4×10(-4)[Nep√(pulse number)] for an averaged value for multiple laser shots. Also the wavelength reproduceability of a dye laser was examined, which resulted in that a computer should take a part in the wavelength control in order that this method should be feasible.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-03-05
13巻
開始ページ 195
終了ページ 207
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307857
JaLCDOI 10.18926/15740
フルテキストURL Mem_Sch_Eng_OU_14_1_55.pdf
著者 古賀 隆治| Hirao, Keiji| Kosaka, Megumi| Sano, Hiroya|
抄録 An absorption spectrum of γ-0 band of nitric monoxide of very dilute density was taken. An experimental electronic device showed a distinguishing power of 0.01 ppm through 10 m optical pathlength. By the aid of a data processing based on a principle developed by the authors, this sensitivity does not suffer from coexisting sulfur dioxide, which shares the absorption band with the nitric monoxide.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1979-12-01
14巻
1号
開始ページ 55
終了ページ 60
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307855
JaLCDOI 10.18926/15741
フルテキストURL Mem_Sch_Eng_OU_14_2_13.pdf
著者 古賀 隆治| Ebara, Masami| Kosaka, Megumi| Sano, Hiroya|
抄録 A switch element has been developed so that a kilovolt step voltage should be supplied to a 50Ω transmission line with a subnanosecond rise time. The element is of silicon substrate with high purity and a pair of electrodes is attached by the evaporation process. The switch action is performed by the photoconductivity produced by the laser light pulse. This paper deals with a preliminary analysis, manufacturing processes and experimental results of the optoelectronic switch. A performance of 320V output with less than 4 ns risetime was obtained with sufficient persistence for more than 2×10(5) pulse shots. This switch was successfully applied to an optical waveform monitor for laser light pulses giving a resolution less than 2 ns.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1980-03-01
14巻
2号
開始ページ 13
終了ページ 22
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307887
JaLCDOI 10.18926/15776
フルテキストURL Mem_Sch_Eng_OU_15_2_79.pdf
著者 古賀 隆治| Nagase, Satoru| Kosaka, Megumi| Sano, Hiroya|
抄録 A method to monitor atmospheric gas concentration employing a tunable diode laser is proposed. An apparatus was built and experiments were made. The tunable diode laser employed was of'PbSnTe with its wavenumber about 1200 cm(-1) at a temperature of 77 K. Methane concentration in laboratory atmosphere was measured on the experiments. The inquired gas-density is obtained by a hardwired microcomputer incorporating the measured absorption spectrum over a prescribed range instead of an absorption at a single wavenumber. By this, drift type noises are suppressed. After an analysis based on experimental data, an attainable sensitivity for methane was found to be 1 ppb.m. This value may increase if an etalon fringe interference exists. The natural concentration, about 1 ppm, of atmospheric methane was actually measured with a short optical path of only one meter.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1981-03-30
15巻
2号
開始ページ 79
終了ページ 92
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307246
JaLCDOI 10.18926/15392
フルテキストURL Mem_Fac_Eng_OU_27_1_45.pdf
著者 香川 直己| 和田 修己| Hai, Xu| 古賀 隆治| Sano, Hiroya| Inubushi, Kazuyuki|
抄録 A prototype device based on the tunable diode laser absorption spectrometry was constructed and the atmospheric methane concentration near the terrain in a rice paddy field was measured. An open optical path of 50 m length was employed along with a PbSnTe diode laser. Diurnal change of methane density with 30 seconds temporal resolution was recorded associated with meteorological parameters. A feasibility was proven for a practical application for in situ study of atmospheric methane.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1992-11-25
27巻
1号
開始ページ 45
終了ページ 53
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307877
JaLCDOI 10.18926/15416
フルテキストURL Mem_Fac_Eng_OU_26_1_43.pdf
著者 Bouzidi, Moncef| 古賀 隆治| 和田 修己| 香川 直己| Hai Xu| 小坂 恵| Sano HIroya|
抄録 A numerical technique called as "adjoint spectrum" has been proposed by the authors in a previous work. Two applications of it are presented here. It is demonstrated that by generalizing the aspect of adjoint spectrum it becomes possible to measure densities of mixed gases simultaneously. An experimental proof of this has been carried on and simultaneous measurement of densities of both methane and dinitrogen oxide was realized. On the other hand, it is also reported that frequency shifting of spectra, which is a cause of error in spectrometric measurements, can be corrected by exploiting the adjoint spectrum technique in connection with the Taylor expansion. Numerical examples showing the success of this method are reported as well.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1991-11-30
26巻
1号
開始ページ 43
終了ページ 49
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307796
JaLCDOI 10.18926/15458
フルテキストURL Mem_Fac_Eng_OU_28_2_33.pdf
著者 Wang, Ming| Ahmed, Anis| 和田 修己| 古賀 隆治|
抄録 Proposed here is a convenient optical system to collimate the crescent shaped blue laser beam radiated from a Cerenkov SHG in channel waveguide configuration. This collimation system is consisted of a parabolic mirror and has a very large tolerance to the mirror displacement. The anisotropy of the nonlinear crystal on which the waveguide is fabricated has been taken into account. The optimum mirror location is given to obtain a collimated blue laser beam with an aberration less than 0.07λ. By using an objective lens, the collimated beam can be focused down to a thin beam with the spot size less than 1μm.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1994-03-15
28巻
2号
開始ページ 33
終了ページ 44
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307149
JaLCDOI 10.18926/15488
フルテキストURL Mem_Fac_Eng_OU_25_1_37.pdf
著者 Bouzidi, Moncef| 古賀 隆治| 和田 修己| 香川 直己| Hai, Xu| 小坂 恵| Sano, Hiroya|
抄録 Is proposed a tunable diode laser absorption spectrometer system which employs a pulsed current to drive the diode laser still implementing a second-harmonic detection methods enhancing a signal to noise up to 104 times that the case without it. This system affords the lead-salt diode laser a higher operating temperature which allows a more compact deep cooling system. A principle is based on employing a gated integrator between the preamplifier and the lock-in amplifier. Investigations are made on the optimum selection of the gating aperture time interval as determined by response time of the infrared detector and the pulse width of the laser driving current.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1990-12-14
25巻
1号
開始ページ 37
終了ページ 50
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307549
JaLCDOI 10.18926/15774
フルテキストURL Mem_Sch_Eng_OU_18_1_91.pdf
著者 Sano, Hiroya| 古賀 隆治| Kosaka, Megumi| Wake, Ichiro|
抄録 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.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1984-03-30
18巻
1号
開始ページ 91
終了ページ 100
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307204
JaLCDOI 10.18926/15794
フルテキストURL Mem_Sch_Eng_OU_19_2_13.pdf
著者 古賀 隆治| Kosaka, Megumi| Sano, Hiroya|
抄録 A quasi-random method for spectral scanning is proposed to reduce an alias response to a quick change in the source abundance. A direct application is made for an atmospheric methane monitoring with a current-tunable diode laser. Only barrel shift methods are examined being found further vulnerable to drifting etalon fringes.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1985-02-25
19巻
2号
開始ページ 13
終了ページ 22
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308000
JaLCDOI 10.18926/14158
フルテキストURL Mem_Fac_Eng_39_1_93.pdf
著者 五百旗頭 健吾| 豊田 啓孝| 和田 修己| 古賀 隆治|
抄録 The optical properties of clouds were measured with a polarization Mie lidar during April, 2004 and investigated to categorize the particles detected by the lidar. The cloud layers were categorized into five types according to the depolarization ratios, as follows: (I) constant and small (less than 5%); increasing with height (II) nearly from 0% and (III) from about 50%; (IV) large and varying with the backscattering coefficient; and (V) sharply decreasing. This categorization of clouds enabled us to separate aerosols from clouds in a lidar signal. Comparison of the backscattering coefficients between clouds of types (I) and (II) suggested that the depolarization ratio induced by multiple scattering in dense clouds does not depend on the particle density. Estimation of the particle phase for the five cloud categories was also examined.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2005-01
39巻
1号
開始ページ 93
終了ページ 101
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308479
JaLCDOI 10.18926/15360
フルテキストURL Mem_Fac_Eng_OU_34_27.pdf
著者 Wei, He| 古賀 隆治| 五百旗頭 健吾| 和田 修己| 豊田 啓孝|
抄録 In spring of 1998, Asian dust was observed with a Mie LIDAR in Okayama University, which can measure depolarization ratio. Three events of intense Asian dust were occurred in the period and medially detailed structure of atmosphere was found after examining records. Asian dust was distinguished from water droplets and the possibility to study three dimensional dynamic structure of atmosphere were demonstrated.
キーワード Mie lidar Asian dust (KOSA) depolarization ratio backscattering ratio range normalized
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2000-03-27
34巻
1-2号
開始ページ 27
終了ページ 37
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307539
JaLCDOI 10.18926/15384
フルテキストURL Mem_Fac_Eng_OU_30_1_99.pdf
著者 Wang, Ming| 和田 修己| 古賀 隆治|
抄録 A cylindric mirror was used, in place of a parabolic mirror, to collimate the crescent blue laser beam radiated from the Cerenkov SHG in channel waveguide configuration. The cylindric mirror radius is requested to be twice the focal length of the parabolic mirror. The focusing effect of the cylindric mirror in collimation can be compensated by slightly lifting the mirror in its normal direction. Under the condition that the mirror was declined by 5.56° and lifted by 25 μm, we got the collimated beam with divergence angle less than 1.3 mrad. In the focusing experiment, the collimated beam was focused with spotsize of 1.8 μm. The details on the analysis and experiment are reported.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1995-12-28
30巻
1号
開始ページ 99
終了ページ 110
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307418
JaLCDOI 10.18926/15419
フルテキストURL Mem_Fac_Eng_OU_29_2_49.pdf
著者 Ahmed, Anis| Taniguchi, Shinji| 和田 修己| Wang, Ming| 古賀 隆治|
抄録 For weakly guiding dielectric waveguides, the eigenmode field distributions are calculated numerically with a simple algorithm. In this numerical method, the transverse sampling space can be chosen arbitrarily, and hence a narrow waveguide can be analyzed. The field satisfying scalar wave equation is expressed by the discrete Fourier transform and the mode eigenvalues and eigenfunctions are calculated by solving an eigenvalue equation numerically. The validity of this method is checked for 2-D waveguides having step and parabolic or square index distributions. It is found that for the well guided TE modes of the slab waveguide, the accuracy of this method is remarkably good, but some discrepancies are found if the mode is near cut off. In the problems where the normalized guide index b is small, caution should be taken in applying the results of this numerical method.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1995-03-27
29巻
2号
開始ページ 49
終了ページ 55
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307858