排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
Keishi Sakamoto Atsushi Kasugai Masaki Tsuneoka Koji Takahashi Yukiharu Ikeda Tsuyoshi Imai Takashi Nagashima Mitsuru Ohta Tsuyoshi Kariya Kenichi Hayashi Yoshika Mitsunaka Yosuke Hirata Yasuyuki Itoh Yukio Okazaki 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(9):1637-1654
A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER. The oscillation mode is TE31,8. In a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A. The efficiency was 22%. In the depressed collector operation, 500kW/36%/50ms was obtained. The maximum efficiency of 40% was obtained at PRF=470kW whereas the power decrease by the electron trapping was observed. Pulse extension was done up to 10s at PRF=170kW with the depressed collector operation. The power was limited by the temperature increase of the output window. 相似文献
2.
Y. Itoh Y. Mitsunaka K. Sakamoto T. Nagashima 《Journal of Infrared, Millimeter and Terahertz Waves》1992,13(9):1353-1359
An experiment was carried out for transforming the 120 GHz-TE12.2 whispering-gallery mode (WGM) into a circularly polarized hollow radiation beam. A hollow beam was formed by reflecting the WGM, which was radiated from a 16 mm radius circular waveguide cut, with an annular mirror having suitable local normal vectors. The experimentally observed field intensity profiles of the reflected wave were in good agreement with calculated results. 相似文献
3.
Yasutoshi Akiyama Yoshika Takenaka Tomoko Kasahara Takaaki Abe Yoshihisa Tomioka Pavel Ivanov 《International journal of molecular sciences》2022,23(21)
Under stress conditions, transfer RNAs (tRNAs) are cleaved by stress-responsive RNases such as angiogenin, generating tRNA-derived RNAs called tiRNAs. As tiRNAs contribute to cytoprotection through inhibition of translation and prevention of apoptosis, the regulation of tiRNA production is critical for cellular stress response. Here, we show that RTCB ligase complex (RTCB-LC), an RNA ligase complex involved in endoplasmic reticulum (ER) stress response and precursor tRNA splicing, negatively regulates stress-induced tiRNA production. Knockdown of RTCB significantly increased stress-induced tiRNA production, suggesting that RTCB-LC negatively regulates tiRNA production. Gel-purified tiRNAs were repaired to full-length tRNAs by RtcB in vitro, suggesting that RTCB-LC can generate full length tRNAs from tiRNAs. As RTCB-LC is inhibited under oxidative stress, we further investigated whether tiRNA production is promoted through the inhibition of RTCB-LC under oxidative stress. Although hydrogen peroxide (H2O2) itself did not induce tiRNA production, it rapidly boosted tiRNA production under the condition where stress-responsive RNases are activated. We propose a model of stress-induced tiRNA production consisting of two factors, a trigger and booster. This RTCB-LC-mediated boosting mechanism may contribute to the effective stress response in the cell. 相似文献
4.
Y. Hirata K. Hayashi Y. Mitsunaka Y. Itoh T. Sugawara 《Journal of Infrared, Millimeter and Terahertz Waves》1995,16(4):713-733
The design of a 170 GHz, 1 MW-CW gyrotron for electron cyclotron heating of nuclear fusion plasmas is presented. The designed gyrotron incorporates a coaxial cavity to reduce mode competition, and a coaxial electron gun to support the cavity inner conductor. A new mode converter splits the generated wave into two beams and radiates them in different directions. The radiated beams are transmitted to two output windows through two mirror systems, being transformed into Gaussian-like beams. A single-stage depressed collector improves the overall efficiency of the gyrotron and reduces the heat flux to the collector surface. 相似文献
5.
Ryutaro?MinamiEmail author Tsuyoshi?Kariya Tsuyoshi?Imai Yoshika?Mitsunaka Keishi?Sakamoto 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(3):311-319
A high efficiency quasi-optical (QO) mode converter for high-power, low-frequency gyrotron have been designed and tested.
For low-frequency gyrotrons, the scales of the mode converter are comparatively small on the wavelength scale, thus causing
significant diffraction losses. Over-1 MW power gyrotron with TE8,3 cavity at 28 GHz have been developed, which has a high efficiency mode converter designed by the use of numerical methods
for launcher optimization. This calculation is sufficiently optimized to maximize the fractional Gaussian content of the far
field. The total transmission efficiency from the mode converter to output window is 94.7%. For the experimental result of
first tube, the output power of more than 1 MW has been obtained with about 40% efficiency and output burn pattern agrees
fairly with the calculated profiles, which imply the design appropriateness. Besides, the frequency dependence for diffraction
loss is discussed, and these results give the guiding design principle of the mode converter for high-power, low-frequency
and long-pulse gyrotrons. 相似文献
6.
Yang Xuhua Takeshi Furuhashi Kenzo Obata Yoshika Uchikawa 《Computers & Industrial Engineering》1996,30(4):1037-1045
This paper presents a new method to select features of handwritten signatures using the genetic algorithm. In the proposed method, the features are determined by chromosomes. The genotypes are modified by the genetic algorithm with a local improvement mechanism. A new crossover method is also proposed to determine the number of features used for signature verification. Furthermore, the moving traces of the pen in the air above the tablet are also included in the candidate strokes. Experiments are done to show the effectiveness of the new method. 相似文献
7.
The nuclear spin-lattice relaxation rate R
s in a Kondo superconductor has been calculated numerically in the framework of the Müller-Hartmann-Zittartz depairing theory. The calculations have been performed in the case of the usual Korringa mechanism for certain concentrations of magnetic impurities and some typical values of T
K/T
c0, where T
K is the Kondo temperature and T
c0 is the superconducting transition temperature in the absence of magnetic impurities. The temperature variation of R
s shows very interesting behavior for values of T
K/T
c0corresponding to the reentrance behavior of superconductivity. Results are compared with the experimental data on the La(Ce)Al2 system obtained by MacLaughlin, Alloul, and Daugherty. Other possible relaxation mechanisms in the La(Gd, Ce)Al2 systems are also discussed. 相似文献
8.
Tsuyoshi Kariya Ryutaro Minami Tsuyoshi Imai Mao Ota Youichi Endo Shin Kubo Takahashi Shimozuma Hiromi Takahashi Yasuo Yoshimura Satoshi Ito Takahashi Mutoh Keishi Sakamoto Yoshika Mitsunaka 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(3):295-310
A 28 GHz 1 MW with TE8,3 cavity for GAMMA10 tandem mirror and a 77 GHz 1.5 MW gyrotron with TE18,6 for Large Helical Device (LHD) have been developed to upgrade their Electron Cyclotron Heating (ECH) systems. In the 28 GHz gyrotron, the maximum power of 1.05 MW was obtained, which is in agreement with its design target value. And the high efficiency of 40% without collector potential depression (CPD) was obtained with 0.8 MW. In the first and second 77 GHz gyrotrons, 0.8 MW 3.6 sec., 0.3 MW 60 sec operations have been achieved, but several issues due to the stray RF and velocity dispersion have been found, too. In consideration of these, the design improvement was performed to aim at 1.5 MW in the third tube. In the short pulse test, the maximum output power of 1.6 MW and the maximum total efficiency of 49.4% with CPD were obtained. In the long pulse test, the pulse length extended to 5 sec with 1 MW, 1800 sec with 0.1 MW, 1.6 sec with 1.5 MW. Total injection power of 3.1 MW to LHD plasma has been achieved. It is shown that the electron beam pitch factor ?? decreases with increasing of beam current, comparing with the experimental and calculation results. 相似文献
9.
10.
Kunihisa Kato Yoshika Hatasako Makoto Kashiwagi Harutoshi Hagino Chihaya Adachi Koji Miyazaki 《Journal of Electronic Materials》2014,43(6):1733-1739
In this study, we investigated the effect of the structure of microporous p-type (Bi0.4Te3Sb1.6) and n-type (Bi2.0Te2.7Se0.3) BiTe-based thin films on their thermoelectric performance. High-aspect-ratio porous thin films with pore depth greater than 1 μm and pore diameter ranging from 300 nm to 500 nm were prepared by oxygen plasma etching of polyimide (PI) layers capped with a heat-resistant block copolymer, which acted as the template. The cross-plane thermal conductivities of the porous p- and n-type thin films were 0.4 W m?1 K?1 and 0.42 W m?1 K?1, respectively, and the dimensionless figures of merit, ZT, of the p- and n-type BiTe films were estimated as 1.0 and 1.0, respectively, at room temperature. A prototype thermoelectric module consisting of 20 pairs of p- and n-type strips over an area of 3 cm × 5 cm was fabricated on the porous PI substrate. This module produced an output power of 0.1 mW and an output voltage of 0.6 V for a temperature difference of 130°C. The output power of the submicrostructured module was 1.5 times greater than that of a module based on smooth BiTe-based thin films. Thus, the thermoelectric performance of the thin films was improved owing to their submicroscale structure. 相似文献