应用CASSCF方法精确计算OH分子A~2∑~+态势能曲线

应用Gaussian03程序包中提供的完全活性空间自洽场(CASSCF)方法,采用多种标准基组对OH分子A~2∑~+态的几何结构进行了优化和势能曲线计算、并将计算结果拟合成了解析的Murrell-Sorbie函数.利用得到的解析势能函数进一步计算了该态的光谱常数,并与实验结果进行了比较.此外,本文还给出了一种新的活性空间的选择方法.     

基于固相抗体模式时间分辨荧光免疫分析测定雌三醇

采用二步标记法,借助二乙烯三胺五乙酸酐,将Eu3+标记到雌三醇完全抗原上,基于固相抗体竞争反应模式,建立了时间分辨荧光免疫分析测定雌三醇的新方法。在优化的条件下,方法的线性范围为0.005—1000ng·mL-1,检出限为4pg·mL-1。该方法用于检测血清中雌三醇的含量,结果令人满意。     

Noise Effects on Temperature Encoding of Neuronal Spike Trains in a Cold Receptor

We examine how noise interacts with encoding mechanisms of neuronal stimulus in a cold receptor. From ISI series and bifurcation diagrams it is shown that there are considerable differences in interval distributions and impulse patterns caused by purely deterministic simulations and noisy simulations. The ISI-distance can be used as an effective and powerful way to measure the noise effects on spike trains of the cold receptor quantitatively. It is also found that spike trains observed in cold receptors can be more strongly affected by noise for low temperatures than for high temperatures in some aspects; meanwhile, the spike train has greater variability with increasing noise intensity.     

边界层转捩区声辐射的预报方法研究

对Lighthill剪切应力脉动模型和Liepmann位移厚度脉动模型进行了讨论,在此基础上,本文提出利用Krane偶极子声源模型对Liepmann单极子声源模型进行改进。数值计算结果表明:作为偶极子声源的Lighthill理论剪切应力脉动模型,预报的噪声级偏低;而作为单极子声源的Liepmann模型,预报的噪声级又偏高;本文提出的两种改进模型预报的噪声级则与Lauchle实验值的一致性较好。     

Mass of Open Cluster NGC 7789

Mass of open duster NGC 7789 in the Galaxy is determined by three methods： the photometric method based on mass-luminosity relations of stars in the duster Mpho= 7712.5M⊙; the dynamical method based on virial theorem Mvir=6996.1M⊙; and the tidal radius method based on the interaction between the cluster and the Galaxy Mtid= 5152.5M⊙. The mean mass of this cluster is estimated to be Mc =6620.4 4- 762.5M⊙.     

Transmission Bandwidth Tunability of a Liquid-Filled Photonic Bandgap Fiber

A temperature tunable photonie bandgap fiber （PBGF） is demonstrated by an index-guiding photonic crystal fiber filled with high-index liquid. The temperature tunable characteristics of the fiber are experimentally and numerically investigated. Compression of transmission bandwidth of the PBGF is demonstrated by changing the temperature of part of the fiber. The tunable transmission bandwidth with a range of 250nm is achieved by changing the temperature from 30℃ to 90℃.     

Training Effect and Hysteretic Behaviour of Angular Dependence of Exchange Bias in Co/IrMn Bilayers

The training effect and the hysteresis behaviour of the angular dependence of exchange bias are extensively investigated upon the variation of the IrMn layer thickness tXrMn in a series of Co/IrMn bilayers. When tIrMn is very small, both of them are negligible. Then they increase very sharply with increasing tUMn and then reach maxima at almost the same value OftXrMn. Finally they both decrease when tIrMn is further increased. The similar variation trends suggest that these phenomena arise from irreversible change of antiferromagnet spin orientations, according to the thermal activation model.     

Halopentacenes: Promising Candidates for Organic Semiconductors

We introduce polar substituents such as F, C1, Br into pentacene to enhance the dissolubility in common organic solvents while retaining the high charge-carrier mobilities of pentacene. Geometric structures, dipole moments, frontier molecule orbits, ionization potentials and electron affinities, as well as reorganization energies of those molecules, and of pentacene for comparison, are successively calculated by density functional theory. The results indicate that haiopentacenes have rather small reorganization energies （〈 0.2 eV）, and when the substituents are in position 2 or positions 2 and 9, they are polarity molecules. Thus we conjecture that they can easily be dissolved in common organic solvents, and are promising candidates for organic semiconductors.     

NMR在天然产物选择性分离与结构研究中的应用

核磁共振(NMR)是天然产物化学研究的重要手段. 本工作将核磁共振技术作为选择性提取分离的监测手段,依据目标化合物的NMR谱学特征,以¹H NMR监控和指导从植物体中寻找和得到二萜类化合物收到了较好的效果. 并运用多种核磁共振技术对分离得到的3种二萜类化合物(jolkinolide A、jolkinolide B和17-hydro-xyjolkinolide B)进行了结构解析.     

A new cell for X-ray absorption spectroscopy study under high pressure

X-ray absorption fine structure (XAFS) spectroscopy is a powerful technique for the investigation of the local environment around selected atoms in condensed matter. XAFS under pressure is an important method for the synchrotron source. We design a cell for a high pressure XAFS experiment. Sintered boron carbide is used as the anvils of this high pressure cell in order to obtain a full XAFS spectrum free from diffraction peaks. In addition, a hydraulic pump was adopted to make in-suit pressure modulation. High quality XAFS spectra of ZrH2 under high pressure (up to 13 Gpa) were obtained by this cell.