42 resultados para Metastasio, Pietro, 1698-1782.

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The microstructure of computer generated nanocrystalline coppers is simulated by using molecular dynamics with the Finnis-Sinclair potential, analysed by means of radial distribution functions, coordination number, atomic energy and local crystalline order. The influence of the grain size on the nanocrystalline structure is studied. The results reveal that as the grain size is reduced, the grain boundary shows no significant structural difference, but the grain interior becomes more disordered, and their structural difference diminishes gradually; however, the density and the atomic average energy of the grain boundary present different tendencies from those of the grain interior.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

基于强度分布变换的高功率激光进行了活塞热疲劳模拟实验。为摸索该实验系统下的实验参数,深入研究了激光能量分布、加载功率、加载周期(升温时间和降温时间)和输出波形等对活塞热疲劳实验的影响,实验表明调节这些参数可以控制活塞顶部温度场分布、温度循环的平均温度、温度差和循环频率,并结合热疲劳相关理论探讨了激光参数对热疲劳寿命影响的规律。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Depth profiles of carrier concentrations in GaMnSb/GaSb are investigated by electrochemistry capacitance-voltage profiler and electrolyte of Tiron. The carrier concentration in GaMnSb/GaSb measured by this method is coincident with the results of Hall and X-ray diffraction measurements. It is indicated that most of the Mn atoms in GaMnSb take the site of Ga, play a role of acceptors, and provide shallow acceptor level(s).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

通道式感应加热技术是最有前景的中间罐钢水加热技术之一。本文综述了连铸中间罐通道式感应加热技术的基本原理、设备构成、技术特点以及与此有关的钢水加热和流动特性。简单介绍了它在中间罐钢水温度控制和成份调整的一些试验研究和在线应用的结果。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

2005年9月30日,中国科学院上海光学精密机械研究所陈昆研究员领导的生物光子学研究小组与上海应用物理研究所李文新研究员领导的小组在对碳纳米管靶向药物传递细胞模型的合作研究中取得新发现:积聚在生物细胞中的碳纳米管对激光能量具有强烈吸收效应,并将光能量迅速转化为热能,产生的热效应导致了细胞的立刻崩溃。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The absorption characteristic of lithium niobate crystals doped with chromium and copper (Cr and Cu) is investigated. We find that there are two apparent absorption bands for LiNbO3:Cr:Cu crystal doped with 0.14 wt.% Cr2O3 and 0.011 wt.% CuO; one is around 480 nm, and the other is around 660 nm. With a decrease in the doping composition of Cr and an increase in the doping composition of Cu, no apparent absorption band in the shorter wavelength range exists. The higher the doping level of Cr, the larger the absorbance around 660 nm. Although a 633 nm red light is located in the absorption band around 660 nm, the absorption at 633 nm does not help the photorefractive process; i.e., unlike other doubly doped crystals, for example, LiNbO3:Fe:Mn crystal, a nonvolatile holographic recording can be realized by a 633 nm red light as the recording light and a 390 nm UV light as the sensitizing light. For LiNbO3:Cr:Cu crystals, by changing the recording light from a 633 nm red light to a 514 nm green light, sensitizing with a 390 nm UV light and a 488 nm blue light, respectively, a nonvolatile holographic recording can be realized. Doping the appropriate Cr (for example, N-Cr = 2.795 X 10(25)m(-3) and N-Cr/N-Cu = 1) benefits the improvement of holographic recording properties. (c) 2005 Optical Society of America.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A theoretical study of the behaviour of partially coherent beams propagating through oceanic turbulence has been performed. Based on the previously developed knowledge of beam spreading of a partially coherent beam in the atmosphere and the spatial power spectrum of the refractive index of ocean water, we study the normalized root-mean-square width of a partially coherent beam on propagation through oceanic turbulence and its turbulence distance which may be a measure of turbulence resistance. Our analysis indicates that the behaviour of partially coherent beams on propagation may be described by the rate of dissipation of the mean-squared temperature chi(T) and that of salinity chi(S). In terms of a quantity w that defines the contributions of the temperature and salinity distributions to the distribution of the refractive index, chi(S) could be written as a function of chi(T) and w. Therefore, the behaviour of partially coherent beams on propagation can be characterized only by chi(T) for a given w. The results are shown for curved surfaces, from which one can see that partially coherent beams exhibit robust turbulence resistance when the water volume has a smaller chi(T).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We demonstrate theoretically and experimentally compensation for positive Kerr phase shifts with negative phases generated by cascade quadratic processes. Experiments show correction of small-scale self-focusing and whole-beam self-focusing in the spatial domain and self-phase modulation in the temporal domain. (C) 2001 Optical Society of America.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

为了提高惯性约束聚变高功率激光系统的整体效率和充分利用光能,需要将高斯分布的光束整形为空间均匀分布的平顶光束。本文从球面透镜的琼斯矩阵出发,利用光学传输矩阵对双折射透镜组空间光束整形系统进行了理论分析,数值模拟了整形效果,讨论了透镜组参量的选择以及中心加工厚度误差等因素带来的影响,并对该系统进行了实验研究。在实验中,利用该双折射透镜组整型系统实现了光束的均匀化输出。在神光Ⅱ第九路中,在近场静态工作条件下,可将光束填充因子从原来的66%提高到80%。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本发明涉及一种姚虻唾液腺免疫调节肽及其基因和应用,属于生物医学领域。该免疫调节肽是中国虻科昆虫唾液腺免疫调节肽基因编码的一种线状多肽,其全序列为:甘氨酸-甘氨酸-缬氨酸-丝氨酸-甘氨酸-缬氨酸-丝氨酸-天冬氨酸-苯丙氨酸-谷氨酸-脯氨酸-异亮氨酸-谷氨酸-缬氨酸-丝氨酸- 甘氨酸-谷氨酸-天冬氨酸-酪氨酸-天冬酰胺-丝氨酸-天冬氨酸-谷氨酸 -丙氨酸-天冬氨酸-谷氨酸-天冬氨酸-甘氨酸-赖氨酸-丙氨酸。免疫调节肽基因由362个核苷酸组成,其中编码成熟编码姚虻唾液腺免疫调节肽为第 115-204位核苷酸。该姚虻唾液腺免疫调节肽作为抑制多种细胞因子的应用。本发明的免疫调节肽具有结构简单、人工合成方便、抗菌活性强等特点。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本发明属于生物医学领域。大蹼铃蟾抗菌肽,为从中国两栖类动物大蹼铃蟾皮肤分泌物中分离得到的一种单链多肽,分子量2697.6,等电点10.2,多肽一级全序列结构为:NH2—GIGGVLLSAGKAALKGLAKVLAAKYANN-NH2。制备方法是将活体大蹼铃蟾用水清洗干净,置于带盖的玻璃容器中,滴加无水乙醚,密闭容器3—5分钟,可见大量的泡沫状物质从大蹼铃蟾皮肤分泌出来,收集分泌物,离心去除沉淀、冷冻干燥后,经离子交换、凝胶过滤、高压液相反相柱层析分离纯化后即得到。大蹼铃蟾抗菌肽具有广谱和显著的抑制细菌和真菌生长作用,作为广谱抗微生物物质在制备治微生物感染疾病药物的应用。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

国家“十五”重大科技专项(2202AA601021); 国家杰出青年科学基金项目(39925007); 中国科学院知识创新工程重要方向项目(KSCX2SW102); 中国科学院水生生物研究所学科前沿课题(2002); 淡水生态与生物技术国家重点实验室课题(2002FB11)项目资助

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new highly pathogenic muscle-infecting species of the genus Myxobolus Butschli, 1882 is described from the Prussian carp, Carassius gibelio (Bloch, 1782) using spore morphology and SSU rDNA sequence data. Phylogenetic analyses elucidated relationship of the newly described Myxobolus lentisuturalis to other Myxobolus species and supported its position of an independent species.