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991.
在作者已给出的描述三螺旋蛋白质分子的哈密顿函数基础上,得到了孤立子存在的临界温度和热容器,其结果与实验结果一致。 相似文献
992.
Guo H. Wu D.S. Liu G. Miao Y.H. Qian S.Z. Qin W.Z. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(3):326-333
A theory is proposed for the special complex cavity; it is in the form of a single resonant circuit having a TE0n&lrarr2;TE0,n+p mode converter and it features excellent mode selectivity, high power capability, and an asymmetric triangle profile of the RF field that is favourable to efficient operation for a 35-GHz second-harmonic gyromonotron employing this complex cavity with TE03 mode output are numerically illustrated and experimentally demonstrated. Power as high as 200 kW and efficiency as high as 30% have been obtained. These experimental results are record values for a gyrotron operating at the second-harmonic millimeter wavelength. Implications of the single-resonant complex cavity for the fundamental harmonic and third-harmonic high-average-power gyrotron design are discussed 相似文献
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994.
In a previous paper by the authors, the computational expressions for the higher order terms of the radiative perturbation series have been developed, and numerical results have been obtained. In this paper, new computational expressions are developed that use the analytic Green's function and the GDOM code, which were developed recently by Qin and Box. Our analysis and numerical computations indicate that the new scheme dramatically improves the efficiency of the computation (by reducing the CPU-time to less than 2% of that required by the previous scheme), and the huge demand on memory usage has been completely removed. This new scheme allows us to expand the high order perturbation computations to more general cases, for example, to include azimuth dependence, and to use the perturbation theory in more potential applications. 相似文献
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996.
G.-M. Kim H. Qin X. Fang F. C. Sun P. T. Mather 《Journal of polymer science. Part A, Polymer chemistry》2003,41(24):3299-3313
Polyhedral oligosilsesquioxane (POSS)-reinforced thermosets based on octaglycidyl epoxy polyhedral oligosilsesquioxane cured with 4,4′-diaminodiphenyl sulfone (DDS) were prepared and studied for their cure, thermomechanical, and microstructural characteristics. Particular attention was paid to nanometer-scale deformation processes responsible for toughening, as revealed by transmission electron microscopy (TEM) in conjunction with the thermal properties. A cure analysis investigated with calorimetry and rheometry showed a significant dependence of the cure mechanism and kinetics on the DDS content, but all hybrid thermosets reacted completely below 300 °C into rigid solids. A dynamic mechanical analysis of this hybrid resin system showed that increasing the DDS concentration used during cure increased the dynamic storage modulus in the glassy (temperature < glass-transition temperature) and rubbery (temperature > glass-transition temperature) states, simply through an increase in the crosslink density. The phase structures revealed by TEM with selective POSS staining were drastically affected by the DDS concentration and manifested as altered nanomechanical deformation structures. It was qualitatively found that the main toughening mechanism in the studied POSS-reinforced thermosets was void formation at the nanometer scale, possibly templated by limited POSS aggregation. As the crosslinking density increased with the DDS concentration, microshear yielding between voids prevailed, providing a balance of stiffness, strength, and toughness. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3299–3313, 2003 相似文献
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999.
采用自制的近红外双波长脑血氧监测仪实时采集人脑血和氧的数据,应用功率谱和相关函数的方法对采集的脑血氧的数据波形进行分析.结果发现正常人脑血氧波形之间有着严格的相关性,功率谱曲线主频峰清晰,血氧的功率谱曲线吻合好;脑缺氧病人血氧波形间的相关性差,功率谱曲线表现为主频峰不清晰,功率谱曲线吻合性差。临床试验表明:脑血氧波形、功率谱和相关函数对于分析人脑血、氧生理状况及其变化具有较好的效果。 相似文献
1000.
Zixiong Qin Qingke Zeng Xiang Yang Dejun Feng Lei Ding Guiyun Kai Zhiguo Liu Shuzhong Yuan Xiaoyi Dong Ning Liu 《Photonics Technology Letters, IEEE》2001,13(4):326-328
Bidirectional chirp-free tuning in Bragg reflection wavelength by as much as 12.52 mm has been achieved based on the principle of a beam of uniform strength. The experimental results are in good agreement with the theoretical analysis. The tuning device is simple in configuration, low cost, and easy to operate, which can be used in numerous applications, such as tunable fiber grating lasers and reconfigurable wavelength add-drop multiplexers, etc 相似文献