39 resultados para Embree, Elihu, 1782-1820.
em Chinese Academy of Sciences Institutional Repositories Grid Portal
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。
Resumo:
An embedded cell model is presented to obtain the effective elastic moduli and the elastic-plastic stress-strain relations of three-dimensional two-phase particulate composites. Each cell consists of an ellipsoidal inclusion surrounded by a finite ellipsoidal matrix that embedded in an infinite matrix. When both matrix and particle are elastic, the effective elastic moduli are derived which is an exact analytic formula without any simplified approximation that can be expressed in an explicit form. Further, the elastic-plastic stress-strain relations are obtained for spherical cells and oblate spheroid cells, in which the matrix is elastic and the particle is elastic-plastic. In addition, the macroscopic elastic-plastic constitutive relation of particle reinforced composites (PRC) is investigated by a systematic approach [1] in which the matrix is elastic-plastic and the particle is elastic.
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).
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。
Resumo:
The ablation in zinc selenide (ZnSe) crystal is studied by using 150-fs, 800-nm laser system. The images of the ablation pit measured by scanning electronic microscope (SEM) show no thermal stress and melting dynamics. The threshold fluence is measured to be 0.7 J/cm2. The ultrafast ablation dynamics is studied by using pump and probe method. The result suggests that optical breakdown and ultrafast melting take place in ZnSe irradiated under femtosecond laser pulses.
Resumo:
unavailable<br>H. Sun's e-mail address is shy780327@siom.ac.cn.
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).
Resumo:
We describe the use of a Wigner distribution function approach for exploring the problem of extending the depth of field in a hybrid imaging system. The Wigner distribution function, in connection with the phase-space curve that formulates a joint phase-space description of an optical field, is employed as a tool to display and characterize the evolving behavior of the amplitude point spread function as a wave propagating along the optical axis. It provides a comprehensive exhibition of the characteristics for the hybrid imaging system in extending the depth of field from both wave optics and geometrical optics. We use it to analyze several well-known optical designs in extending the depth of field from a new viewpoint. The relationships between this approach and the earlier ambiguity function approach are also briefly investigated. (c) 2006 Optical Society of America.
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。
Resumo:
本发明公开了一种多功能可调猴椅,包括由侧板及前、后面板围接而成的可供被实验动物进入其中的座位空间,该座位空间的上方安装有上面板和头部固定板;所述侧板的内侧安装有若干条固定槽,在固定槽的内侧开设凹槽,用于安装配套插件;所述侧板的外侧安装有旋转固定件,该旋转固定件与定位架连接,用于调整定位架的位置。该猴椅具有良好的通用性,可根据实验需要进行调节,而且安装方便,适用于对各种年龄和体型的灵长类动物的科研实验。
Resumo:
研究了温度、营养和光强对发状念珠藻(NostocflagelliformeBorn.etFlah.)生长的影响.结果表明,温度、营养和光强的变化影响其生长速率和细胞的生化组成.藻细胞在25oC温度与45mol/(m2s)光强下培养分别得到最大比生长速率;而N,P和Ca2+缺乏显著降低细胞的比生长速率,微量元素As和K缺乏对细胞生长速率没有明显影响.随着培养温度的增加,胞外多糖含量逐渐下降;而不同光强对胞外多糖含量也具有显著影响,高光强和低光强下的多糖含量均高,而15~45mmol/(m2s)光强下的胞外多
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.
Resumo:
The electronic structure and electron g factors of HgTe quantum dots are investigated, in the framework of the eight-band effective-mass approximation. It is found that the electron states of quantum spheres have aspheric properties due to the interaction between the conduction band and valence band. The highest hole states are S (l = 0) states, when the radius is smaller than 9.4 nm. the same as the lowest electron states. Thus strong luminescence from H-Te quantum dots with radius smaller than 9.4 nm has been observed (Rogach et al 2001 Phys. Statits Solidi b 224 153). The bandgap of H-Te quantum spheres is calculated and compared with earlier experimental results (Harrison et al 2000 Pure Appl. Chem. 72 295). Due to the quantum confinement effect, the bandgap of the small HgTe quantum spheres is positive. The electron g factors of HgTe quantum spheres decrease with increasing radius and are nearly 2 when the radius is very small. The electron g factors of HgTe quantum ellipsoids are also investigated. We found that as some of the three dimensions increase, the electron g factors decrease. The more the dimensions increase, the more the g factors decrease. The dimensions perpendicular to the direction of the magnetic field affect the g factors more than the other dimension.
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).