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991.
Ammonium perchlorate (AP)-based composite propellant has been widely used as a solid propellant, but higher burning rates are in demand. We report that crystal-habit-modified AP is an effective oxidizer that increases the burning rates of propellants. The modified APs have a dendritic shape. However, dendritic AP is not convenient to mix and cast in an AP/binder slurry because of its high viscosity. We attempted to prepare a crystal-habit-modified AP with polygon or sphere form. The crystal habit of AP was modified by ethylene glycol such that the intensity of the lattice plane (2 1 0) of the modified AP was remarkably high. The shape was almost hexahedral, and the mean particle diameter was approximately 150 μm. 相似文献
992.
Masamichi Takebe Makoto Ohya Ryo Adachi Koji Doi Naoki Kitagawa Keishi Ochibe 《Corrosion Science》2010,52(9):2928-2935
This study compares the precipitation rates of air-borne salts analyzed by the dry gauze method (JIS Z2382) and the Doken (Public Works Research Institute) tank method. Because of the difference of calculation method, direction of prevailing wind causes the difference of salt precipitation rates by these methods. In addition, the Doken tank method has lower capture ability for air-born salt than the dry gauze method under the condition of low supply of air-born salt. While, air-born salt with wet deposition potentially increases salt precipitation of the Doken tank method. As a result, these methods yield different salt precipitation rates. 相似文献
993.
Myoungseok Lee Makoto Uchida Donald A. Tryk Hiroyuki Uchida Masahiro Watanabe 《Electrochimica acta》2011,(13):4783
In our previous work, we have proposed a new method to estimate the effective Pt utilization or “effectiveness” (EfPt) using the ratio of the mass activity (MA) for the oxygen reduction reaction in the membrane-electrode assembly (MEA) in the polymer electrolyte fuel cell to that in the channel flow double electrode measurement, MAmax, under similar conditions. In the present research, applying this method, we have focused on elucidating the effect of the thickness of the catalyst layer (CL), the effect of Pt-based alloy catalysts, and effect of the state of dispersion of the Pt/C catalysts in the CL in measurements carried out at 80 °C and various relative humidities (RH), in either O2 or air. The effect of a thin CL (0.04 mg cm−2, Pt/C) has improved EfPt by a factor of four, going from 3% to 12%, and the integrated effect of a thin CL and alloying (0.05 mg cm−2 Pt3Co) has improved EfPt by a factor of six, going from 3% to 17% for air at 0.85 V, Tcell = 80 °C, and 30% RH. Furthermore, we found that the EfPt values were dependent upon the state of Pt dispersion in the CL. The highest EfPt value obtained thus far for air at 0.85 V, Tcell = 80 °C, and 100% RH was ca. 22%, shown by a low Pt loading CL diluted with added uncatalyzed carbon black (0.04 mg cm−2, overall average 30 wt%-Pt). 相似文献
994.
Yu You Mikako Kato Makoto Ohtsuka Hiroyuki Fukuyama 《Journal of the American Ceramic Society》2013,96(10):3054-3060
The effects of ZrO2 additions to Al2O3 were investigated to improve the evaporation rate of Al2O3 for bulk AlN crystal growth. The evaporation rate of Al2O3 increased concomitantly with increasing ZrO2 concentration under a nitrogen gas stream at 2223 K. The ZrO2 was predominantly nitrided. The nitridation of ZrO2 kept the local oxygen partial pressure high at the pellet surface, which suppressed the nitridation of Al2O3. The nitridation of ZrO2 caused the outward diffusion of ZrO2 (Zr4+ and O2?) in the pellet, which was accelerated further by the presence of Al2O3–ZrO2 liquid phase in grain boundaries, leading to the prompt formation of ZrN porous layer on the pellet surface. The suppressed nitridation of Al2O3 and the formation of porous ZrN layer were the reasons for the enhanced evaporation of Al2O3, leading to enhanced bulk AlN growth. 相似文献
995.
Makoto Souwa Daichi Yamazaki Michio Okada Akitaka Yoshigoe Yuden Teraoka Toshio Kasai 《Electrical Engineering in Japan》2011,175(4):43-47
We report the results of a study of the natural oxidation of Cu3Au(110) with high‐resolution X‐ray photoemission spectroscopy in conjunction with synchrotron radiation. The clean surface of Cu3Au(110) is terminated with 50% Au and 50% Cu atoms. After natural oxidation in the air, Cu atoms segregate on the surface and produce Cu‐oxide. As a result, Au atoms move into the bulk. Au atoms below the oxide reduce the diffusion of O atoms farther into bulk and limit the oxide thickness. The face dependence of natural oxidation indicates that the diffusion of Cu atoms also contributes to oxide formation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 43–47, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21149 相似文献
996.
Evidence for Charge‐Trapping Inducing Polymorphic Structural‐Phase Transition in Pentacene 下载免费PDF全文
997.
Takao Ito Seigo Matsuno Zengyu Xia Makoto Sakamoto Rajiv Mehta 《Artificial Life and Robotics》2010,15(3):249-252
In a keiretsu, i.e., a set of companies with interlocking business relationships, it is important for corporate management to identify
those companies over which they reciprocally exercise greater influence and power. In this article we employ a DEcision MAking
Trial and Evaluation Laboratory (DEMATEL) to illustrate the reciprocal influence of each company in Mazda’s Yokokai keiretsu, as measured by the number of transactions and cross-shareholdings. Furthermore, we calculate the centrality index of each
company, and then analyze the relationship between centrality index and influence in order to identify the determinants of
the influence. Based on the findings, we identify some characteristics of effective relationships which have important managerial
implications. 相似文献
998.
999.
1000.
The diffusion coefficients of pullulan added in gellan gum solutions as a probe polymer were measured using pulsed-field-gradient stimulated-spin-echo (PFG-Ste) 1H NMR in order to investigate the gelation mechanism and gel structure. The echo intensity of gellan was steeply decreased at around the gelling temperature Tgel indicating stiffening of the gellan chains upon aggregation and formation of the network. The diffusion coefficient of pullulan Dpull increased with decreasing temperature below Tgel. This result suggests that the decrease in concentration of solute gellan in the interspaces of the network below Tgel, as evidenced by the decrease in its echo intensity, leads to an overall decrease of hydrodynamic interactions between gellan and pullulan. The characteristic hydrodynamic shielding length ξ was calculated from the relation Dpull/Dpull,0 = exp(−Rh/ξ), where Dpull,0 is Dpull in dilute solution and Rh is the hydrodynamic radius of pullulan. The temperature dependence of ξ, which was investigated for varying concentrations of several cations, was found to follow closely the gelling temperature, and in particular, showing a very similar thermal hysteresis. 相似文献