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1.
MASASHI KOTARI TOMO TADOKORO SHIN‐ICHI TANAKA MIKIMASA IWATA TADASHI AMAKAWA 《Electrical Engineering in Japan》2016,195(3):26-37
From an environmental viewpoint, when carrying out internal arc tests on SF6‐insulated power equipment, it is necessary to prevent SF6 from being released into the atmosphere or to replace SF6 with air in accordance with IEC standards. However, the pressure rise and the thermal effect of the hot gas exhausted during arcing when testing in air are still considerably different from those for testing in SF6. Thus, it is necessary to propose a specific procedure to replace SF6 with air and to select appropriate parameters for the tests. Therefore, it is desirable to clarify the equivalent conditions causing these phenomena both experimentally and analytically. In this paper, we describe the effect of the charged gas pressure in a closed container on the pressure rise due to air and SF6 arcing and the ratio of the arc energy to the energy contributing to the internal pressure rise () from an experimental viewpoint. Additionally, to research the energy balance resulting from SF6 arcing in the container, the energy balance is discussed on the basis of chemical reactions, radiation, and the melting and vaporization of the electrodes. It is found that the maximum pressure rise increases for both gases upon increasing the gas pressure from 0.1 MPa to 0.4 MPa. Subsequently, good agreement with the energy balance was obtained under reasonable assumptions by taking account of the energy components related to the chemical reactions, radiation, and the melting and vaporization of the electrodes. The ratio of the radiation energy loss to the total consumption energy increased upon increasing the charged gas pressure. 相似文献
2.
For scalar quadratic optimal linear systems with a white gain coefficient, the influence of the uncertainty of the gain variance is analysed by means of elementary methods. First, the mean-square stability of the closed loop systems is analysed on the assumption that the controller is designed with an erroneous variance. It is shown that the use of an overestimated value of the variance less than a threshold value, which is infinite for the stable free systems, does not damage the stability of closed-loop systems. A relative underestimation error bound guaranteeing the stability of closed-loop systems is obtained. Secondly, performance of the controller designed with an erroneous variance is compared analytically with that of the certainty equivalence controller. An explicit relative overestimation error bound on the variance guaranteeing the superiority of the controller over the certainty equivalence controller is obtained. 相似文献
3.
KIJA LEE KAHO UEGAKI CHIHIRO NISHII TADASHI NAKAMURA AUSKA KUBOTA TSUNAO HIRAI KAZUTAKA YAMADA 《International Journal of Dairy Technology》2012,65(2):232-236
Computed tomography (CT) was performed on Gouda‐type cheese during ripening to evaluate gas hole formation and structural quality. The cheese was exposed to different ripening conditions, including variations in ripening temperature and concentration of butyric acid bacteria. Computed tomography images were obtained every 2 weeks for 16 weeks to assess the volume, shape and location of gas holes. The results demonstrate that CT makes the nondestructive monitoring of cheese gas hole formation and evaluation of the structural features of cheese possible throughout the ripening period. 相似文献
4.
Winding Method to Reduce Vibration and Loss Caused by Fractional Slot of Synchronous Machine 下载免费PDF全文
DAISUKE HIRAMATSU KAZUMA TSUJIKAWA TAKASHI UEDA MASAFUMI FUJITA HIROAKI ISHIZUKA MASASHI OKUBO HIDEYUKI HACHIYA JUNJI MORI DAI NOZAKI DAISUKE IWASHITA TADASHI TOKUMASU 《Electrical Engineering in Japan》2017,198(2):39-49
Fractional‐slot windings are widely used in rotating machines in order to improve the output voltage waveform, increase the design flexibility, and gain many other advantages. However, fractional‐slot windings are known to produce different harmonic components such as an even order and/or fractional number of space flux harmonics compared to integral‐slot windings. These harmonics may increase stray losses and cause stator core vibration. This paper describes an analysis of space flux harmonics and proposes new winding methods such as “novel interspersed windings” to reduce these harmonic components. The proposed winding methods were verified by numerical analysis and model tests. 相似文献
5.
Experimental Verification for Practical Application of Inductive Power Transfer System for Railway 下载免费PDF全文
Inductive Power Transfer systems (IPT systems) for moving Electrical Vehicles (EVs) are often discussed. However, an IPT system for moving railway vehicles has not been sufficiently examined. In order to employ the IPT system for railway vehicles, this paper examines the characteristics of railway IPT systems, such as efficiency, temperature rise, and durability. Because the required characteristics of the IPT system for railway are different from those of EV, one example of a railway IPT system is proposed, and the verification items for practical use are examined. Moreover, we manufactured test equipment that can imitate the field environment in order to verify these items before practical use in the field. The test procedure and test results demonstrate the possibility of practical use of a railway IPT system. 相似文献
6.
TADASHI SUZUKI 《Electrical Engineering in Japan》2017,199(2):47-57
The kHz band power line communication (PLC) is one of the convincing mediums of the communication system for smart meter reading. Data transmission between medium‐voltage (MV) and low‐voltage (LV) points to pass the transformer by PLC is interested. In this paper, the PLC signal propagation characteristics between points of MV at substation and LV at customer are calculated and analyzed. The results show that direct communication between points on MV distribution line and most LV customers is impossible due to large propagation losses at MV–LV transformer and on LV distribution line. 相似文献
7.
TADASHI IZUTSU SHIN'ICHI TANEYA EIICHI KIKUCHI TOSHIMARO SONE 《Journal of texture studies》1981,12(2):259-273
To establish a relationship between perceived sweetness intensity (Y), sucrose concentration (A%) and viscosity of mixed solutions (B poise), mixtures of sucrose solutions in various concentration and sodium carboxymethylcellulose with medium viscosity (CMC–M) in various concentrations were used, resulting in the equation: where "Y"= sucrose concentration of reference solutions. This equation was effective within the ranges of 4% to 16% sucrose and viscosities of from 1 to 100 poises. This equation was applicable to low and high as well as medium viscosity forms of CMC. 相似文献
8.
This paper presents a novel type of flux‐modulating synchronous machine (FMSM) in which permanent magnets (PMs) are embedded in the stator back‐iron. The rotor has neither windings nor PMs. A prototype machine with an outer‐rotor configuration was designed and manufactured to validate the operating principle of the FMSM. The characteristics in the motor mode of the prototype machine were also investigated with a vector control system. The results of the investigations show that, as in surface‐mounted PM motors, the torque of the FMSM is predominantly generated by the PM flux and can be controlled using the armature current. 相似文献
9.
JUNICHIRO MIZUSAKI TADASHI SASAMOTO† W. R. CANNON‡ H. KENT BOWEN 《Journal of the American Ceramic Society》1982,65(8):363-368
Electronic conductivity and Seebeck coefficients of LaFeO3 were measured as a function of temperature (1000° to 1400°C) and P ( O 2 ) (105 to 10−13 Pa). Electronic conduction was found to be n-type in the lower P ( O2 ) range, and p -type in a higher P(O2 ) range. The calculated carrier mobilities suggest a hopping-type conduction mechanism. The carrier concentrations were calculated as a function of P ( O2 ) and the defect structure was described. It was found that the electrical properties of LaFeO3 are determined not only by the concentration of oxygen vacancies, but also by the La/Fe ratio. 相似文献
10.