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排序方式: 共有2544条查询结果,搜索用时 187 毫秒
41.
H. Ebe T. Okamoto H. Nishino T. Saito Y. Nishijima M. Uchikoshi M. Nagashima H. Wada 《Journal of Electronic Materials》1996,25(8):1358-1361
CdTe epilayers were grown directly on (100), (211), and (111) silicon substrates by metalorganic chemical vapor deposition
(MOCVD). The crystallinity and the growth orientation of the CdTe film were dependent on the surface treatment of the Si substrate.
The surface treatment consisted of exposure of the Si surface to diethyltelluride (DETe) at temperatures over 600°C prior
to CdTe growth. Direct growth of CdTe on (100) Si produced polycrystalline films whereas (lll)B single crystals grew when
Si was exposed to DETe prior to CdTe growth. On (211) Si, single crystal films with (133)A orientation was obtained when grown
directly; but produced films with (211)A orientation when the Si surface was exposed to DETe. On the other hand, only (lll)A
CdTe films were possible on (111) Si, both with and without Te source exposure, although twinning was increased after exposure.
The results indicate that the exposure to a Te-source changes the initial growth stage significantly, except for the growth
on (111) Si. We propose a model in which a Te atom replaces a Si atom that is bound to two Si atoms. 相似文献
42.
The integral experiment on beryllium with D-T neutrons for verification of tritium breeding 总被引:1,自引:0,他引:1
Yury Verzilov Satoshi Sato Kentaro Ochiai Masayuki Wada Axel Klix Takeo Nishitani 《Fusion Engineering and Design》2007,82(1):1-9
A clean benchmark experiment on beryllium was performed with D-T neutrons at the FNS facility of the Japan Atomic Energy Agency. The main objective was to verify the integral data related to the tritium production on lithium isotopes. Tritium production rates, as well as activation reaction rates were measured inside the beryllium assembly that was shaped as a pseudo-cylindrical slab with an area-equivalent diameter of 628 mm and a thickness of 355 mm. Experimental results were analyzed with a three-dimensional Monte Carlo transport code MCNP-4C and FENDL/MC-2.0, JENDL-3.2/3.3 neutron transport libraries. Evaluation of reaction rates was based on the cross section data taken from the JENDL Dosimetry File and ENDF B-VI data libraries. Analysis shows that all calculation combinations (transport and activation cross section libraries) used for evaluation of reaction rates give data that is agreeable with measured values within 10%. 相似文献
43.
In rats, galanin modulates luteinizing hormone (LH) secretion, and gonadotropin-releasing hormone (GnRH) neurons provide a possible source of this galanin. To understand galanin's physiological role in GnRH neurons, we used double-label in situ hybridization and computerized image analysis to examine the regulation of galanin message in GnRH neurons. We found that galanin gene expression in GnRH neurons is regulated by sex steroids, induced coincident with the LH surge, and persists well after the completion of the LH surge, and that the induction of galanin message in GnRH neurons coincident with the LH surge is sexually differentiated neonatally. We postulate that the rise in galanin gene expression in GnRH neurons at the time of the LH surge serves to replenish galanin released with GnRH that is needed for the production of the LH surge, or that galanin is involved in physiological events that occur subsequent to the LH surge. 相似文献
44.
JL Vallet RK Christenson WE Trout HG Klemcke 《Canadian Metallurgical Quarterly》1998,76(10):2657-2670
This experiment consisted of the following treatment-breed groups: 1) White crossbred gilts, 2) White crossbred gilts treated with progesterone (200 mg/d in corn oil given on d 2 and 3 after estrus), and 3) Chinese Meishan gilts. Pregnant and nonpregnant gilts (n=3 to 6) from each treatment-breed combination were assigned to be slaughtered on d 10, 11, 12, 13, and 15. At slaughter each uterine horn was flushed with 20 mL of minimal essential medium. Uterine flushings were assayed for total protein, acid phosphatase, uteroferrin, retinol-binding protein, and oxytocin. Uterine flush total protein was increased by progesterone treatment, was unaffected by pregnancy status, and was less in Meishans. Similar patterns were found for retinol binding protein and uteroferrin, except that uteroferrin was greater in pregnant than in nonpregnant gilts. Oxytocin was greater in pregnant than in nonpregnant gilts, was not influenced by progesterone treatment, and was similar in Meishan and in White crossbred gilts. These results indicate that the conceptus does not influence secretion of either total protein or retinol binding protein during pregnancy and that the onset of secretion of these uterine proteins may be controlled by progesterone. The presence of the conceptus is associated with increased uteroferrin and oxytocin production. The decreased secretion of uterine proteins in Meishan gilts may partially explain the slower embryonic development that has been reported for this breed. 相似文献
45.
CE Verrijt MJ Kroos MI Huijskes-Heins HG van Eijk JP van Dijk 《Canadian Metallurgical Quarterly》1998,19(7):525-530
BACKGROUND: Glucocorticoids have been linked to self-administration of a wide range of drugs in animals and are increased endogenously by chronic nicotine intake. Corticosteroids have also been shown to regulate nicotine receptor sensitivity and to be involved in behavioral sensitization to nicotine. METHODS: Cortisol levels and cortisol suppression in response to dexamethasone were measured in a sample of smokers participating in a smoking cessation treatment trial. RESULTS: Cortisol levels dropped significantly during the early quitting process (2 weeks post-quit) and returned to a level below baseline 1 month post-quit. The magnitude of the initial drop in cortisol was strongly related to post-quit distress and marginally predictive of abstinence. Neither baseline nor post-quit changes in percent cortisol suppression after dexamethasone were related to abstinence success or withdrawal distress. CONCLUSIONS: Withdrawal from cigarette smoking is marked by a reduction in cortisol levels that appears to be related to the degree of distress experienced during the early quitting period. Further work is needed to determine whether withdrawal-related cortisol changes or distress are predictive of abstinence success. 相似文献
46.
We describe the case of a young woman with pain on turning her head attributable to a malformation of the hyoid bone. Diagnosis was established using spiral computed tomography with the patient's neck in the position of greatest discomfort and with 3-dimensional reconstruction of the hyoid bone. Prior conventional radiography and magnetic resonance imaging did not aid in finding a diagnosis. After surgical removal of both greater cornua of the hyoid bone there was a complete relief of symptoms. 相似文献
47.
Synthesis and characterization of silicon nitride whiskers 总被引:2,自引:0,他引:2
Silicon nitride whiskers were synthesized by the carbothermal reduction of silica under nitrogen gas flow. The formation of silicon nitride whiskers occurs through a gas-phase reaction, 3SiO(g)+3CO(g)+2N2(g)=Si3N4()+3CO2(g), and the VS mechanism. The generation of SiO gas was enhanced by the application of a halide bath. Various nitrogen flow rates resulted in different whisker yields and morphologies. A suitable gas composition range of N2, SiO and O2 is necessary to make silicon nitride stable and grow in a whisker form. The oxygen partial pressure of the gas phase was measured by an oxygen sensor and the gas phase was analysed for CO/CO2 by gas chromatography. Silicon nitride was first formed as a granule, typically a polycrystalline, and then grown as a single crystal whisker from the {1 0 0} plane of the granule along the 210 direction. The whiskers were identified as-sialon with Z value ranging from 0.8 to 1.1, determined by lattice parameter measurements. 相似文献
48.
A population protocol is one of distributed computing models for passively-mobile systems, where a number of agents change
their states by pairwise interactions between two agents. In this paper, we investigate the solvability of the self-stabilizing
leader election in population protocols without any kind of oracles. We identify the necessary and sufficient conditions to
solve the self-stabilizing leader election in population protocols from the aspects of local memory complexity and fairness
assumptions. This paper shows that under the assumption of global fairness, no protocol using only n−1 states can solve the self-stabilizing leader election in complete interaction graphs, where n is the number of agents in the system. To prove this impossibility, we introduce a novel proof technique, called closed-set
argument. In addition, we propose a self-stabilizing leader election protocol using n states that works even under the unfairness assumption. This protocol requires the exact knowledge about the number of agents
in the system. We also show that such knowledge is necessary to construct any self-stabilizing leader election protocol. 相似文献
49.
Shingo Kanehira Soshu Kirihara Yoshinari Miyamoto Kazuaki Sakoda Mitsuo Wada Takeda 《Journal of the American Ceramic Society》2003,86(10):1691-1694
Photonic crystals with a diamond structure of epoxy lattices in which TiO2 -based ceramic particles are dispersed were fabricated by stereolithography. The periodicity of the lattice was designed to reflect electromagnetic waves in the gigahertz range. The volume fraction (β) of the dielectric lattice medium was modified from 14% to 33% by changing the rod diameter of the lattice. The photonic band gap was observed along Γ-L 〈111〉, Γ-X 〈100〉, and Γ-K 〈110〉 directions and the complete photonic band gap was formed at over β= 20%. The width of the forbidden gap increased gradually when the β increased over 14%, and reached 2.4 GHz at β= 33%. These results agreed with the band calculation using the plane wave expansion method. 相似文献
50.
Curing catalyst for epoxy resins was newly found. The catalyst consists of aluminum complex and silanol. Lack of one component of the pair does not cure epoxy resins. The epoxy resins cured with the catalyst are characterized by excellent electrical properties, especially at high temperature, due to the absence of strong acid species in the cured epoxy resin matrix. Heat-resistant property of the resin was also excellent. These properties were compared with those of epoxy resin cured with commonly used BF3 complex. 相似文献