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51.
本运用模糊仿真技术中的近似推理方法和差分原理,求解具有模糊不确定性时的二阶微分方程的边值问题.  相似文献   
52.
We present our recent work on both linear and nonlinear data reduction methods and algorithms: for the linear case we discuss results on structure analysis of SVD of column-partitioned matrices and sparse low-rank approximation; for the nonlinear case we investigate methods for nonlinear dimensionality reduction and manifold learning. The problems we address have attracted great deal of interest in data mining and machine learning.  相似文献   
53.
查子初  王志群 《实验力学》1991,6(2):169-176
本文提供了一种可以进行自增强处理的圆筒试样,通过实验用柔度法确定了该试样的表面裂纹的应力强度因子,介绍了含表面裂纹试样的柔度测试技术,导出了柔度与表面裂纹尖端前缘各点的应力强度因子的关系式,该式可作为各种含表面裂纹试样柔度法测表面裂纹 K_1因子的参考,本文还测定了不同自增强程度下,自增强圆筒的表面裂纹疲劳扩展规律。  相似文献   
54.
查全性 《物理》1998,27(10):592-598
在综述电化学近50年来比能量提高情况的基础上,讨论了现代科技发展对电池比能量的要求,以及当今电池能在多大程度上满足这些要求,并讨论了进一步提高电池比能量的可能性及可能途径.  相似文献   
55.
The effects of ultraviolet-C radiation (UV-C, 11.8?W/m2), single-cycle and multiple-cycle high hydrostatic pressure (HHP at 200, 400 or 600?MPa) on microbial load and physicochemical quality of raw milk were evaluated. Reductions of aerobic plate count (APC) and coliform count (CC) by HHP were more than 99.9% and 98.7%, respectively. Inactivation efficiency of microorganisms increased with pressure level. At the same pressure level, two-cycle treatments caused lower APC, but did not show CC differences compared with single-cycle treatments. Reductions of APC and CC by UV-C were somewhere between 200?MPa and 400/600?MPa. Both HHP and UV-C significantly decreased lightness and increased pH, but did not change soluble solids content and thiobarbituric acid-reactive substances’ values. Two 2.5?min cycles of HHP at 600?MPa caused minimum APC and CC, and maximum conductivity. Compared with HHP, UV-C markedly increased protein oxidation and reduced darkening.  相似文献   
56.
We demonstrate the generation of two-mode continuous-variable (CV) entanglement in a V-type three-level atom trapped in a doubly resonant cavity using a microwave field driving a hyperfine transition between two upper excited states. By numerically simulating the dynamics of this system, our results show that the CV entanglement with large mean number of photons can be generated even in presence of the atomic relaxation and cavity losses. More interestingly, it is found that the intensity and period of entanglement can be enhanced significantly with the increasing of the atomic relaxation due to the existence of the perfect spontaneously generated interference between two atomic decay channels. Moreover, we also show that the entanglement can be controlled efficiently by tuning the intensity of spontaneously generated interference and the detuning of the cavity field.  相似文献   
57.
One new alkaloid, named caldaphnidine H ( 1 ), together with eight known ones, daphnioldhanin G ( 2a ), methyl homosecodaphniphyllate ( 3 ), daphnezomine M ( 4 ), daphniyunine A ( 5 ), calyciphylline A ( 6 ), deoxycalyciphylline B ( 7 ), deoxyisocalyciphylline B ( 8 ), and calyciphylline B ( 9 ) was isolated from the leaves and stems of Daphniphyllum calycinum. The structure of 1 was established by spectral methods, especially 2D‐NMR techniques. The structure of daphnioldhanin G ( 2b ) reported previously was revised to 2a mainly by single‐crystal X‐ray diffraction and spectral analysis.  相似文献   
58.
Decabromodiphenyl ether (BDE209) is poorly absorbed by mammals, and little information is available on the toxicokinetics of BDE209 and its metabolites in fish. In the present study, rainbow trout (Oncorhynchus mykiss) were administered to 100 ng/g and 500 ng/g body wet weight of BDE209 via a single intraperitoneal injection and parent BDE209 and its metabolites were sequentially monitored for 28 days. The results showed that toxicokinetic profiles of BDE209 could be described by the one-compartment model. In the higher dose group (500 ng/g wet weight), the calculated half-life (t 1/2) and elimination rate (k e) were 17.7 d and 0.039/d in the liver, and 100.3 d and 0.007/d in the muscle, respectively. Three major methoxylated brominated diphenyl ethers (MeO-BDEs) were detected with 2,2′,4,4′-tetrabromo-5-methoxydiphenyl ether (5-MeO-BDE47) being detected in all tissue samples. There was no significant temporal change of 5-MeO-BDE47 concentration in the muscle, whereas an exponential increase was observed in the liver. Therefore, the metabolism rate of BDE209 depended on the administered dose. BDE209 was hardly accumulated in the muscle of rainbow trout, while the liver was a primary metabolic organ. MeO-BDEs were formed via metabolism of BDE209, which probably played a significant role in fish toxicology as a potential indicator.  相似文献   
59.
The present paper mainly studied the phase formation and reaction pathway of the Al–Ti–Si system in detail by thermal analysis combined with XRD and SEM observations. The phase formation sequence in Al–Ti–Si system from starting mixtures to final products with increasing temperature can be described as following: Al(l) + Ti(s) + Si(s) → (Al–Si)(l) + Ti(s) + Si(s) → Ti(Al,Si)3(s) + Si(s)Ti5(Si,Al)3 + Al(l). More importantly, the solubility of Si in Ti(Al,Si)3 decreased gradually while that of Al in Ti5(Si,Al)3 increased with temperature increasing, suggesting the transportation of Si atoms from intermediate aluminides Ti(Al,Si)3 to final stable silicides Ti5(Si,Al)3 and hence further confirming the formation of Ti5(Si,Al)3 at the expense of Ti(Al,Si)3.  相似文献   
60.
The chemical investigation of the aerial parts of Pteris semipinnata resulted in the isolation of three illudalane sesquiterpenoids, namely (2R)‐norpterosin B ( 1 ), (2R)‐12‐Oβ‐D ‐glucopyranosylnorpterosin B ( 2 ), and semipterosin A ( 3 ), along with three known compounds. The structures of 1 – 3 were established by spectroscopic methods, including extensive 2D‐NMR and CD analyses.  相似文献   
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