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31.
A combined cycle power plant, which combines a gas turbine and a steam turbine, can achieve high energy efficiency. Many combined cycle plants have been installed in the world. However, a large-scale blackout occurred in Malaysia in 1996. Combined cycle and gas turbine plants sequentially tripped out. The cause of this chain trip was thought to be a system frequency drop. Considering these backgrounds, it is important to study dynamic behavior of combined cycle plants. Several dynamic models of the combined cycle plant have been proposed. In our analysis, we use some of them and build a model for a single-shaft combined cycle plant. We execute numerical simulations to see how the combined cycle behaves when the system frequency drops. 相似文献
32.
Hitoshi Kakimoto Takehiro Hayashi Hirosi Handa Kenzi Yukihira Yukio Okamura Naotaka Odaka 《Electrical Engineering in Japan》1995,115(5):75-87
This paper describes the development of the Automatic Fault Point Locating and Sectional Isolating System. This system locates a single-line-to-ground fault point at each pole by using ground-current sensors, and isolates the faulted section by controlling pole switches with no outage of unfaulted sections. The ground-current sensor is connected to the line between allied ground terminals of pole devices and grounded conductor. It detects a ground fault current of more than 0.64 amperes that is determined so as to avoid an unexpected operation by stray current, but to detect the fault current accurately, and sends out an emergency signal with time delay of 0.1 s. Sectional isolation starts when both the emergency signal from the sensor and relay operation signals from a substation are received and ends within a feeder circuit-breaker tripping time of 1.5 s. 相似文献
33.
Shigihara K. Nagai Y. Kakimoto S. Ikeda K. 《Quantum Electronics, IEEE Journal of》1994,30(8):1683-1690
A modal reflector, which consists of a high-reflectivity region surrounded by low-reflectivity regions, is added to the front facet of two types of broad-area laser diodes (LD's) to control the lateral modes. One type of LD is the self-aligned laser with a bent active layer (SBA LD) that has a real index-guiding mechanism. The other is a planar-stripe LD that consists of a Zn-diffused region to confine the current flow and has a gain-guiding mechanism. For the SBA LD's with a modal reflector, stable single-lobed far-field patterns (FFP's) are obtained at up to 0.3 and 0.4 W output powers in continuous wave (CW) operation and pulsed operation, respectively. In addition, for planar-stripe LD's with a modal reflector, stable single-lobed FFP's are obtained at up to 0.4 W in CW operation. The lateral modes inside the cavity are analyzed by utilizing a slit model and FFP's are calculated. Good agreement is found between experimental and calculated FFP's for a large Fresnel number 相似文献
34.
Experiments have been carried out, using a semi-batch reactor equipped with a consecutive sampling device, to clarify the effects of catalysts and vehicles in the coal liquefaction process. The results show that a vehicle has a significant effect during preheating, unlike a catalyst which is not effective at this stage. A catalyst is more effective in promoting liquefaction under reaction conditions of 450°C and ≈ 20 MPa than is a vehicle. A vehicle higher in hydrogen donation increases the yield of oil even if a catalyst is present, providing a multiplier effect. In the development of a direct coal liquefaction process, therefore, selection of a vehicle is as important as that of a catalyst. 相似文献
35.
36.
Two kinds of aromatic–aliphatic polyamide oligomers were newly prepared by the reactant pairs of 3,4′-oxydianiline–adipic acid and 3,4′-oxydianiline–azelaic acid. These oligomers were then condensed separately with α, ω-polybutadienedicarboxylic acid giving two series of polybutadiene–polyamide multiblock copolymers. Properties of four series of polybutadiene–polyamide multiblock copolymers, whose polyamide blocks consisted of not only newly prepared polyamides but also previously synthesized aromatic polyamides derived from 4,4′-oxydianiline–isophthalic acid and 3,4′-oxydianiline–isophthalic acid, were investigated on the view point of structure-property relationship. A larger extent of the Tg depression of polybutadiene phase, and higher tensile strength and modulus were observed in the block copolymers having aromatic polyamides compared with those having aliphatic ones. 相似文献
37.
Yasunari Nishikata Masa-aki Kakimoto Atsushi Morikawa Yoshio Imai 《Thin solid films》1988,160(1-2):15-20
Multilayer films of poly(amide-imide)s were prepared as follows: (1) monolayers of long alkyl amine salts of poly(amide-amic acid) were prepared at the air- water interface; (2) these monolayers were deposited on an appropriate plate by the Langmuir-Blodgett method; (3) the multilayers of poly(amide-amic acid) salts on the solid support were treated with acetic anhydride to afford poly(amide-imide) multilayer films. The monolayer thickness of the poly(amide-imide) multilayer films were 0.43–0.55 nm. 相似文献
38.
39.
Okihashi M Osakada M Uchida K Nagayoshi H Yamaguchi T Kakimoto K Nakayama Y Obana H 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2010,51(5):253-257
To conduct proficiency testing for the analysis of pesticide residues in processed foods, fortified samples of retort curry and pancake were examined. In the case of retort curry, heating and mixing were necessary at the time of preparation to provide a homogenous analytical sample. A mixture of 4 carbamates and 11 organophosphorus pesticides was spiked and 14 of them showed consistent results in the samples. In the case of pancake, 10 kinds of pesticides were added to the pastry. The prepared pastry was them cooked. The relative concentrations of most of the pesticides in the pancake were not affected and all the pesticides showed consistent results in the samples. These results showed that the two tested samples were suitable for proficiency testing. 相似文献
40.
Naotaka Ohno Yuya Akeboshi Morihiro Saito Jun Kuwano Hidenobu Shiroishi Toyoki Okumura Yoshiharu Uchimoto 《Topics in Catalysis》2009,52(6-7):903-911
Two types of oxide nanosheet-based materials, H3O+-form regularly stacked manganese oxide nanosheets (H3O+-RG(Mn)) and H3O+-form randomly restacked manganese oxide nanosheets (H3O+-RE(Mn)) were synthesized by soft chemical methods, and their oxygen reduction reaction (ORR) activities were examined by cyclic voltammetry (CV) and semi-steady-state voltammetry (SSV) with a rotating ring-disc electrode at 70 °C in 0.1 M KOH. Both samples showed high onset potentials (E on) of the ORR current and high efficiencies (Eff 4) of the 4-electron reduction of oxygen, and E on and Eff 4 values were improved by electrochemical oxidation up to 1.2 V (vs. reversible hydrogen electrode) in the CV measurement prior to the SSV measurement. As a result, the nanosheet-based samples exhibited higher ORR activities than the starting materials, K+-form layered manganese oxide K0.5MnO2 (K+-RG(Mn)) and Mn2O3, and a well-known ORR catalyst, MnO2. The H3O+-RE(Mn) sample electrochemically oxidized up to 1.2 V showed the highest ORR activity, E on = 0.97 V and Eff 4 = 99%, which were comparable to those of a conventional 20 mass% Pt/C catalyst. The comparison of their ORR activities, BET surface areas and X-ray photoelectron spectra suggests that the enhancement of the ORR activity is attributed to an increase in the numbers of the ORR active sites and a large amount of H2O in the interlayers and on the surface of the nanosheets because of rapid of H2O-supply enough for ORR in alkaline solution. 相似文献