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排序方式: 共有327条查询结果,搜索用时 15 毫秒
321.
We theoretically derive the shape of the Brillouin gain spectrum, that is, the Briilouin backscattered-light power spectrum produced in an optical fiber under conditions of a strain distribution that changes linearly with a constant slope. The modeled measurement system is an optical time-domain reflectometer-type strain sensor system. The linear strain distribution is one of the fundamental distributions and is produced in, for example, a beam to which a concentrated load is applied. By analyzing a function that expresses the shape of the derived Brillouin gain spectrum, we show that the strain calculated from the frequency at which the spectrum has a peek value coincide. with that at the center of the effective pulsed light. In addition, the peak value and the full width at half maximum of the Brillouin gain spectrum are both influenced by the strain difference between the two ends of the effective pulse. We investigate this influence in detail and obtain the relationship between strain difference and strain measurement error. 相似文献
322.
Akiyoshi Ohira Michio Yanadori Kunihiko Iwabuchi Toshikatsu Kimura Yuji Tsubota 《亚洲传热研究》2001,30(2):95-113
This paper deals with the cold energy release characteristics of an ice/air direct contact heat exchanger. Characteristics of the outlet temperature, humidity, and time history of heat release are examined when the initial height of the ice‐cube‐packed bed in the heat exchanger is changed. The following results were obtained in these experiments: (1) Inlet air of 30 °C is lowered to about 0 °C when passed through the heat exchanger, and the absolute humidity of the outlet air is reduced to about a quarter of that of the inlet air. (2) There is an optimum height of the ice‐cube‐packed bed to maximize the amount of cold energy release. (3) This heat exchange method can supply about twice as much cold energy as is released by an ordinary fin‐tube‐type heat exchanger even if the air velocity in the heat exchanger is reduced to about 0.38 times that of the fin‐tube‐type heat exchanger. (4) A nondimensional correlation equation for predicting the time taken for the ice‐cube‐packed bed to completely melt is derived. © 2001 Scripta Technica, Heat Trans Asian Res, 30(2): 95–113, 2001 相似文献
323.
Kiyoshi Okada Akiyoshi Hattori Taketoshi Taniguchi Akihiko Nukui Rathindra Nath Das 《Journal of the American Ceramic Society》2000,83(4):928-932
The effect on the γ-Al2 O3 -to-α-Al2 O3 phase transition of adding divalent cations was investigated by differential thermal analysis, X-ray diffractometry, and surface-area measurements. The cations, Cu2+ , Mn2+ , Co2+ , Ni2+ , Mg2+ , Ca2+ , Sr2+ , and Ba2+ , were added by impregnation, using the appropriate nitrate solution. These additives were classified into three groups, according to their effect: (1) those with an accelerating effect (Cu2+ and Mn2+ ), (2) those with little or no effect (Co2+ , Ni2+ , and Mg2+ ), and (3) those with a retarding effect (Ca2+ , Sr2+ , and Ba2+ ). The crystalline phase formed by reaction of the additive with γ-Al2 O3 at high temperature was a spinel-type structure in groups (1) and (2) and a magnetoplumbite-type structure in group (3). In groups (2) and (3), a clear relationship was found between the transition temperature and the difference in ionic radius of Al3+ and the additive (Δ r ): The transition temperature increased as Δ r increased. This result indicates that additives with larger ionic radii are more effective in suppressing the diffusion of Al3+ and O2− in γ-Al2 O3 , suppressing the grain growth of γ-Al2 O3 , and retarding the transformation into α-Al2 O3 . 相似文献
324.
Taichi Kuroki Kazunori Nagasawa Michael Peters Daniel Leighton Jennifer Kurtz Naoya Sakoda Masanori Monde Yasuyuki Takata 《International Journal of Hydrogen Energy》2021,46(42):22004-22017
This study develops a hydrogen fueling station (HFS) thermodynamic model that simulates the actual fueling process in which hydrogen is supplied from a high-pressure (HP) storage tank into a fuel cell electric vehicle (FCEV) tank. To make the model as accurate as possible, we use the same components and specifications as in actual HFSs, such as a pressure control valve, a pre-cooling system, and an FCEV tank. After the components and their specifications are set, pressure and temperature profiles are set as the HP tank supply conditions. Based on the pressure and temperature profiles, the model solves for the temperature, pressure, and mass flow rate of hydrogen at each downstream position, including the inside of the vehicle tank. The values predicted by the model are compared with experimental data, and we show that the developed model makes it possible to accurately simulate those values at any position during the fueling process. 相似文献
325.
The Rho family of small GTPases (Rho GTPases) act as molecular switches that transduce extrinsic stimuli into cytoskeletal rearrangements. In vascular endothelial cells (ECs), Cdc42, Rac1, and RhoA control cell migration and cell–cell junctions downstream of angiogenic and inflammatory cytokines, thereby regulating vascular formation and permeability. While these Rho GTPases are broadly expressed in various types of cells, RhoJ is enriched in angiogenic ECs. Semaphorin 3E (Sema3E) releases RhoJ from the intracellular domain of PlexinD1, by which RhoJ induces actin depolymerization through competition with Cdc42 for their common effector proteins. RhoJ further mediates the Sema3E-induced association of PlexinD1 with vascular endothelial growth factor receptor (VEGFR) 2 and the activation of p38. Upon stimulation with VEGF-A, RhoJ facilitates the formation of a holoreceptor complex comprising VEGFR2, PlexinD1, and neuropilin-1, leading to the prevention of VEGFR2 degradation and the maintenance of intracellular signal transduction. These pleiotropic roles of RhoJ are required for directional EC migration in retinal angiogenesis. This review highlights the latest insights regarding Rho GTPases in the field of vascular biology, as it will be informative to consider their potential as targets for the treatment of aberrant angiogenesis and hyperpermeability in retinal vascular diseases. 相似文献
326.
Journal of Communications Technology and Electronics - In this paper, belief propagation (BP) iterative estimation of chaos-modulated signals is considered in massive multiple-input multiple-output... 相似文献
327.
Miyako Akiyoshi Hidetsugu Nakamura Yasutake Hara 《Propellants, Explosives, Pyrotechnics》2000,25(5):224-229
As a new azide‐free gas generant, the thermal behavior of the Sr complex nitrate of carbohydrazide was investigated in the mixed system with various oxidizing agents (KClO4, KBrO3, Sr(NO3)2, KNO3). For the differential thermal analysis, the initial temperature of the reaction of mixtures with KBrO3 was lower than that of the pure complex, and the reaction was very vigorous. The reactions with oxidizing agents except for KBrO3 were thought to proceed moderately. The heat of combustion at the stoichiometric composition increased according to the tendency of the calculated theoretical value based on the chemical stoichiometric equation. The burning rate of the KBrO3 system was very high compared with the other mixed systems, and was controlled by the rate of reaction. The pressure dependence was high in the case of using the nitrate as an oxidizing agent. In all the systems, N2 and CO2 gases account for 99% of all the evolved gases during the combustion. In the case of using an oxidizing agent containing a halogen, the halogen ion was only slightly detected during the combustion. 相似文献