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91.
Cuk Supriyadi Ali Nandar Takuhei Hashiguchi Tadahiro Goda Takao Tsuji 《IEEJ Transactions on Electrical and Electronic Engineering》2012,7(4):355-362
This paper presents the design of a coordinated superconducting magnetic energy storage (SMES) and blade pitch controller (BPC) to stabilize the frequency in a smart‐grid power system. To compensate for such power variations, a SMES that is able to supply and absorb active power quickly can be applied to control the frequency fluctuation. The structure of the controller is that of a first‐order lead–lag compensator. The robustness of the controller is guaranteed by applying an inverse additive perturbation to represent possible unstructured uncertainties in the power system such as variation of system parameters, generating and loading conditions, etc. Genetic algorithm (GA) is applied to solve and achieve the control parameters. Simulation studies have been done to show the control effect and robustness of the proposed SMES and blade pitch in comparison with SMES & Pitch against various disturbances. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
92.
Takao Tsuji Kohsuke Tomura Tsutomu Oyama Takuhei Hashiguchi Tadahiro Goda Seiji Tange Toshio Nomura 《Electrical Engineering in Japan》2012,179(1):29-39
In a future distribution network, it will be difficult to maintain system voltage because a large number of distributed generators are introduced into the system. The authors have previously proposed a voltage profile control method using power factor control of distributed generators. When all information on the system is available, an ideal stationary solution of control orders to distributed generators is given by an optimization calculation. However, it is difficult to apply optimization control in real time because a long calculation time is required for the optimization. Therefore, it is possible that a voltage change may occur before the power factor control has finished. Thus, in this paper, we develop a new control method which can save the excessive voltage changes by taking into consideration the controlled response time of distributed generators. The proposed method was tested in a 24‐node distribution network model. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(1): 29–39, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21231 相似文献
93.
Tadahiro Aita Kazunari Ogawa Yusuke Saito Yuichi Sumiyoshi Takeshi Higuchi Shimio Sato 《Surface & coatings technology》2010,205(3):861-866
Atmospheric-pressure inductively coupled micro-plasma jet was used for deposition of SiO2 and TiOx thin films. Si and Ti alkoxides respectively were vaporized into Ar gas to be decomposed thermally in the Ar plasma jet, being deposited as the metal oxide films. Microstructures of the films were investigated as changing the plasma conditions such as Ar gas flow rate and concentration of the alkoxides in Ar gas. The SiO2 and TiOx films deposited at higher Ar gas flow rates were composed of particles of micron or submicron sizes. The SiO2 film was composed of a single layer of the particles and the particles sometimes formed unique aggregation structures. On the other hand, the TiOx film had a structure in which the particles were piled up randomly. The structures suggested that the SiO2 particles grew on the substrate whereas TiOx particles were formed in plasma gas phase. 相似文献
94.
Hirokazu Asahara Daiju Takamizu Masaki Hirayama Shin Saito Tadahiro Ohmi 《Thin solid films》2010,518(11):2953-6157
MgZnO (magnesium-zinc-oxide) films were grown on (11-20) sapphire substrates and Zn-polar ZnO substrates by plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) employing microwave-excited plasma. Structural, electrical and optical properties were investigated by X-ray diffraction, atomic force microscope, Hall, transmittance and photoluminescence measurement. The c-axis lattice constant decreases proportionally to an increase in the Mg content of MgxZn1 − xO films. Therefore, this indicates that Mg atoms can be substituted in the Zn sites. Mg contents in films on ZnO substrates increase up to 0.11. In addition, Ga doped ZnO films were grown on (11-20) sapphire substrates. The resistivity of the films on (11-20) sapphire is controlled between 1.2 × 10− 3 Ω cm to 1 Ω cm by changing the process conditions. The overall results indicate the promising potential of this PE-MOCVD method for related (Zn, Mg)O films formation because of the reactivity of the radicals, such as oxygen radicals (O?). 相似文献
95.
Neurotrophins are a family of secreted proteins expressed in the peripheral nervous system and the central nervous system that support neuronal survival, synaptic plasticity, and neurogenesis. Brain-derived neurotrophic factor (BDNF) and its high affinity receptor TrkB are highly expressed in the cortical and hippocampal areas and play an essential role in learning and memory. The decline of cognitive function with aging is a major risk factor for cognitive diseases such as Alzheimer’s disease. Therefore, an alteration of BDNF/TrkB signaling with aging and/or pathological conditions has been indicated as a potential mechanism of cognitive decline. In this review, we summarize the cellular function of neurotrophin signaling and review the current evidence indicating a pathological role of neurotrophin signaling, especially of BDNF/TrkB signaling, in the cognitive decline in aging and age-related cognitive diseases. We also review the therapeutic approach for cognitive decline by the upregulation of the endogenous BDNF/TrkB-system. 相似文献
96.
Concurrent bombardment of a growing film surface by Ar ions having low kinetic energies comparable to typical inter-atomic
binding energies has been utilized to activate the film surface. It has been shown that such activation is quite effective
and can be substituted for substrate heating during crystal growth. As a result, high quality, device grade epitaxial silicon
films have been successfully grown at very low temperatures of 250°–300° C. In this epitaxial growth process, dopant impurities
in the target are fully incorporated into the grown film and 100% electrically activated at such low temperatures. The direction
for further reducing the epitaxial silicon growth temperature has been examined experimentally, and it is shown that the establishment
of anultra clean processing environment andultra clean wafer surface as well asperfect process parameter control are quite essential for very low temperature silicon epitaxy. 相似文献
97.
A random access optical heterodyne receiver for a coherent FDM broadcasting system has been developed, using a wavelength tunable local DBR LD, polarisation diversity technique and a random access automatic frequency controller. In a 10-channel FDM experimental system, 114 GHz capture range, 80 GHz lock range and arbitrary channel selection within less than 1 ms were realised.<> 相似文献
98.
Emura K. Shibutani M. Cha I. Kitamura M. Yamazaki S. 《Photonics Technology Letters, IEEE》1990,2(8):565-567
Semiconductor optical amplifiers are attractive not only as optical repeaters but also as functional devices, since carrier density modulation in amplifiers causes a nonlinear phenomenon. Utilizing the effect of the carrier density modulation on the semiconductor optical amplifier junction voltage, a coherent optical tapping is proposed for signal monitoring or control signal extraction. A 155 Mb/s FSK (frequency shift keying) signal tapping was realized with a simple configuration using heterodyne single-filter detection with -24.4 dBm sensitivity. Many applications for this coherent optical tapping are discussed, and basic characteristics for frequency-selective tapping from FDM (frequency division multiplexing) signals and optical amplifier gain control are examined 相似文献
99.
Shibutani M. Kanai T. Domom W. Emura W. Namiki J. 《Selected Areas in Communications, IEEE Journal on》1993,11(7):1118-1126
The authors investigate the feasibility of using an optical fiber feeder for microcellular mobile communication systems. The optical feeder enables compact and low-cost base stations, easy radio channel control, and flexible mobile communication systems. Basic transmission characteristics were investigated through optical transmission experiments. Using these results, it is estimated that the optical feeder can transmit 880 telephone channels for digital TDM systems and 2000 channels for analog FDM systems through 20 km of optical fiber. Furthermore, two kinds of novel techniques that enlarge dynamic range of the optical feeder are reported 相似文献
100.