X射线CCD标定及模拟

 在北京同步辐射光源4B7B实验站上,采用透射光栅配X射线电荷耦合元件(CCD)的方法对单色光进行了检验,在优化高次谐波抑制方法后,开展了X射线CCD的灵敏度标定实验研究;在标定数据处理过程中,提出了等效曝光时间的概念,修正了快门开合造成的曝光时间误差。标定实验获得了100~1 500 eV能区CCD的灵敏度,补充了300~600 eV能区CCD灵敏度标定数据,验证了简化模型的正确性。     

低温气液两相流数值计算

低温工质两相流动在很多场合都存在,研究深冷剂在两相流动时参数的分布有着很重要的作用.文中采用一维均相流模型对液氮循环流动过程进行稳态数值模拟,得到了循环流动过程中液氮含汽率、压力和温度沿管程方向的分布情况,并对由于不同回路条件引起的不同结果进行了分析.     

QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems

We review the developments of the multipole expansion approach in quantum chromodynamics and its applications to hadronic transitions and some radiative decays of heavy quarkonia. Theoretical predictions are compared with updated experimental results.     

Investigating the DAMA annual modulation data in the framework of inelastic dark matter

In this paper, the model independent annual modulation effect observed by DAMA during four independent experiments of one annual cycle each (57986 kg day total statistics) is analysed in terms of a particle dark matter candidate which can only inelastically scatter by making a transition to a slightly heavier state, as previously suggested in the literature. Received: 4 October 2001 / Revised version: 16 November 2001 / Published online: 20 December 2001     

Oxygen—evloving Activity in PhotosystemⅡ Core Complex of Photosynthetic Membrane in the Presence of Native Lipid

The techniques of oxygen electrode polarography and Fourier transform infrared (FT‐IR) spectroscopy were employed to explore the involvement of digalactosyl diacylglycerol (DGDG) in functional and structural roles in the photosystem II core complex (PSIICC). It was shown that DGDG exhibited the ability to stimulate the oxygen evolution in PSIICC, which was accompanied by the changes in the structures of PSIICC proteins. The results revealed that there existed hydrogen‐bonding interactions between DGDG molecules and PSIICC proteins. It is most likely that the sites of PSIICC interaction with DGDG are in the extrinsic protein of 33 kDa.     

PROPAGATION OF SURFACE ACOUSTIC WAVES IN PRESTRESSED ANISOTROPIC LAYERED PIEZOELECTRIC STRUCTURES

The propagation of surface acoustic waves in layered piezoelectric structures withinitial stresses is investigated.The phase velocity equations are obtained for electrically free andshorted cases,respectively.Effects of the initial stresses on the phase velocity and the electrome-chanical coupling coefficient for the fundamental mode of the layered piezoelectric structures arediscussed.Numerical results for the c-axis oriented fihn of LiNbO_3 on a sapphire substrate aregiven.It is found that the fractional change in phase velocity is a linear function with the ini-tial stresses,and the electromechanical coupling factor increases with an increase of the absolutevalues of the compressive initial stresses.The results are useful for the design of surface acousticwave devices.     

稀释磁性半导体Sn1-xMnxO2的室温铁磁性

采用固相反应法，制备了不同成分的稀释磁性半导体Sn_1-xMn_xO ₂(x=002，004，006)．利用x射线衍射和傅里叶变换红外光谱法证明 了锰均匀地掺杂到二氧化锡中．在室温下研究了掺锰二氧化锡基稀释半导体的磁性，发现它具有明显的铁磁性 ，同时对磁性的强弱与锰的含量和烧结温度的关系作了研究． 关键词： 稀释磁性半导体 掺杂 烧结 铁磁性 1-xMn_x O₂')" href="#">Sn_1-xMn_x O₂     

Homogeneous catalytic asymmetric dihydroxylation of olefins induced by an efficient and recoverable polymer‐bound ligand QN–AQN–OPEG‐OMe

A novel polymer‐bound alkaloid ligand QN–AQN–OPEG‐OMe, which was characterized by an anthraquinone core at the 9‐O position of quinine, was synthesized conveniently. It delivered up to 99% ees in the homogeneous catalytic asymmetric dihydroxylation of seven olefins, comparable to that reported for the homogeneous catalyst with free ligand (DHQ)₂AQN. This ligand was recovered almost quantitatively by a simple filtration and reused for five cycles without obvious decreased enantioselectivities and catalytic activities. Copyright © 2005 John Wiley & Sons, Ltd.     

TC corrections to tt̄ production at photon colliders in topcolor-assisted multiscale technicolor model

TC(technicolor) corrections to tt? production in high-energy photon-photon collision are calculated in the topcolor-assisted multiscale technicolor(TOPCMTC) model. We find that the contribution of the technipions to the production cross section of the process γγ → tt? is very small. The relative corrections to the production cross section mainly come from the top-pions, which may be observable at future e ⁺ e ^-. linear collider.