Embedded cell model of three-dimensional two-phase composites

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.

Ablation and ultrafast dynamics of zinc selenide under femtosecond laser irradiation

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.

Femtosecond laser-induced breakdown of multilayers and gold film

unavailable<br>H. Sun's e-mail address is shy780327@siom.ac.cn.

Analysis of optical systems with extended depth of field using the Wigner distribution function

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.

多功能可调猴椅

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。

温度、营养和光强对发状念珠藻生长的影响

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

Electronic structure and electron g factors of HgTe quantum dots

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.

The intrinsic temperature effect of the Raman spectra of graphite

The Raman spectra of ion-implanted highly oriented pyrolytic graphite (HOPG) are reported, in which an additional mode at 1083 cm(-1) and three doublet structures in the positions of similar to 1350, similar to 2450, and similar to 2710 cm(-1) are revealed. Noticeable frequency shifts are observed for all the Raman bands between the spectra excited with different laser powers, which are interpreted as the pure temperature effect and a downshift in the C-C stretching frequency induced by the thermal expansion. Moreover, the pure temperature effect (d omega/dT)(V) without anharmonic contribution is achieved in pristine HOPG. The results suggest that the pure temperature effect without anharmonic contribution plays an important role in the frequency shifts with temperature. (C) 1999 American Institute of Physics. [S0003-6951(99)01313-3].

西沙、南沙和中沙群岛进一步开发的设想

论述了西、南、中沙群岛区位的重要性，该区陆地小而海洋国土大，拥有丰富

~(230)Ac β延发裂变

本文叙述了远离beta稳定线新核素合成尤其是beta延发裂变研究的重要意义,介绍了beta延发裂变先驱~(230)Ac的搜索及其延发裂变几率的测定。

空间直观景观模型在呼中林区土壤侵蚀预测研究中的初步应用

土壤通用流失方程 (USLE)已被广泛应用于大尺度的土壤侵蚀预测 .在以往的土壤侵蚀研究中 ,由于只能获得静态的植被图 ,土壤通用流失方程只能用于土壤侵蚀的静态估算 .空间直观景观模型能在大尺度上模拟植被动态 ,为土壤通用流失方程提供动态的植被因子 ,从而使土壤侵蚀的动态模拟成为可能 .本研究结合空间直观景观模型LANDIS和土壤通用流失修正方程 ,以大兴安岭呼中林区为研究区 ,动态地模拟未来 6 5 0年内有采伐和无采伐预案下的土壤侵蚀量 ;同时以无火无采伐预案下的土壤侵蚀为对比值 .结果表明 ,土壤侵蚀量随时间变化呈周期性的波动 ,其波动程度在无火无采伐预案下最小 ,而在有火无采伐预案下最大 ;采伐对土壤侵蚀的影响没有火对土壤侵蚀的影响在空间上表现得明显 ,但是其累积效果则比火的影响强 ;降低采伐所产生的裸露土能有效降低年平均土壤侵蚀量 ,但是对土壤侵蚀动态变化的影响不明显 ;虽然采伐增加使平均土壤侵蚀量增加 ,但是也同时使土壤侵蚀的年际变化更趋于平稳 .

啤酒酿造中污染细菌的研究（二）──污染细菌的数量变化规律与快速检测方法

啤酒酿造中污染细菌的研究（二）──污染细菌的数量变化规律与快速检测方法吴文芳，吕安国，曾青，李波（中国科学院沈阳应用生态所）刘钧信，张庆春，蒋志云（铁岭市清河啤酒厂）啤酒酿造过程中污染细菌的类群组成及数量常随着不同的季节、不同的发酵工段与发酵阶段而有...