三区振幅型三维超分辨光瞳滤波器的优化设计

光瞳滤波器是光学成像系统实现超分辨的基本元件之一，多数三维超分辨滤波器因结构复杂而难于实现。用MATLAB优化工具箱，采用非线性规划，对三区振幅型（1-0—1型）光瞳滤波器进行了三维超分辨优化设计。建立了优化模型，并给出了优化实例。结果表明所设计的滤波器较好地实现了横向和轴向三维超分辨，且轴向超分辨能力优于横向。该滤波器结构简单，容易实现。     

Coordination number of zinc ions in the phosphotriesterase active site by molecular dynamics and quantum mechanics

We have run several molecular dynamics (MD) simulations on zinc-containing phosphotriesterase (PTE) with two bound substrates, sarin and paraoxon, and with the substrate analog diethyl 4-methylbenzylphosphonate. A standard nonbonded model was employed to treat the zinc ions with the commonly used charge of +2. In all the trajectories, we observed a tightly bound water (TBW) molecule in the active site that was coordinated to the less buried zinc ion. The phosphoryl oxygen of the substrate/inhibitor was found to be coordinated to the same zinc ion so that, considering all ligands, the less buried zinc was hexa-coordinated. The hexa-coordination of this zinc ion was not seen in the deposited X-ray pdb files for PTE. Several additional MD simulations were then performed using different charges (+1, +1.5) on the zinc ions, along with ab initio and density functional theory (DFT) calculations, to evaluate the following possibilities: the crystal diffraction data were not correctly interpreted; the hexa-coordinated zinc ion in PTE is only present in solution and not in the crystal; and the hexa-coordinated zinc ion in PTE is an artifact of the force field used. A charge of +1.5 leads to a coordination number (CN) of 5 on both zinc ions, which is consistent with the results from ab initio and DFT calculations and with the latest high resolution X-ray crystal structure. The commonly used charge of +2 produces a CN of 6 on the less buried zinc. The CN on the more buried zinc ion is 5 when the substrate/inhibitor is present in the simulation, and increases to 6 when the substrate/inhibitor is removed prior to the simulation. The results of both of the MD and quantum mechanical calculations lead to the conclusion that the zinc ions in the PTE active site are both penta-coordinated, and that the MD simulations performed with the charge of +2 overestimate the CN of the zinc ions in the PTE active site. The overall protein structures in the simulations remain unaffected by the change in zinc charge from +2 to +1.5. The results also suggest that the charge +1.5 is the most appropriate for the molecular dynamics simulations on zinc-containing PTE when a nonbonded model is used and no global thermodynamic conclusion is sought. We also show that the standard nonbonded model is not able to properly treat the CN and energy at the same time. A preliminary, promising charge-transfer model is discussed with the use of the zinc charge of +1.5.     

CH4, CO2和H2O在非金属原子修饰石墨烯表面的吸附

煤层气(矿井瓦斯)是一种有望替代传统化石燃料，如煤、石油和天然气的非常规气体. 作为可得的清洁能源，它的利用被认为是节能和经济的选择. 在本工作中，非金属原子X(X=H，O，N，S，P，Si，F，Cl)修饰的石墨烯(Gr)被用来代表具有结构异性的煤表面模型. 通过密度泛函理论系统地研究了煤层气组分Y(Y=CH₄，CO₂，H₂O)在非金属原子修饰石墨烯上的吸附作用. 结果表明Y在非金属原子修饰石墨烯上的吸附均为物理吸附. 态密度和差分电荷密度共同表明了这种弱的相互作用.其中，H和Cl对CH₄的作用较大； N、O、F、Cl对CO₂的作用较强； N，Cl对H₂O的影响不容忽视. 总的来说，吸附能大小依次为：H₂O>CO₂>CH₄. 因此，在CH₄富集的煤层里注入H₂O或CO₂可以与CH₄形成竞争吸附，进而提高煤层气采收率. 本工作提供了在分子水平下煤层气与非金属原子修饰石墨烯之间的相互作用的详情，并为煤层瓦斯的开采与分离提供了有用的信息.     

玻碳材料作平台的石墨炉原子吸收光谱研究

使用形影不离碳材料作热解涂层石墨管的恒温平台，利用玻碳材料抗化学腐蚀能力强、使用寿命长和孔隙率低等特点，克服了玻碳管使用温度受电源装置的限制及影响中等蒸发元素测定等问题。初步研究了典型易蒸发元素Ｃｄ和中等蒸发元素Ｃｕ在玻璃平台上的分析性能；比较了不同规格玻璃碳平台与标准石墨平台间的差异以及它们之间抗基体干扰的能力；用扫描电子显微镜观察了它们的表面状态。     

LINEAR ISOSTATIC GRAVITY ANOMALIES IN THE SOUTH CHINA SEA

In this paper a model of linear isostatic gravity has been shown in the South China Sea. By means of resolving a stochastic integral equation, a compensating density, which is corresponding to the topographic masses of unit volume, has been established. By calculation, the average depth of the mantle bottom under the South China Sea is 450 km and the depth of one of the interfaces within the layer B is 250 km. The depression areas of the South China Sea are caused by the surplus of the compensation in the depth between 450 and 560 km. The compensating and isostatic gravity anomalies have been resolved, and a geological interpretation has been made.     

Interaction of host-guest complexes of cucurbit[n]urils with double probe guests

Since the structure of cucurbituril(Q[6]) has been determined in 1981[1] and its homologues cucurbit [n = 5,7,8 and 10]uril(Q[5], Q[7], Q[8] and Q[10]) have been reported in 2000[2,3], 2002[4], a series of host-guest complexes[5—7], novel supramolecular as-semblies[8—10], molecular encapsulates[11,12] and mo-lecular containers[13,14] based on Q[n] have been stud-ied extensively. All cucurbituril homologues have common char-acteristic features, i.e. hydrophobic cavity, and polar carbonyl gr…     

Cu(100)表面HCOO对CO2吸附的稳定作用

采用广义梯度近似(GGA)的密度泛函理论(DFT)(DFT-GGA)并结合平板模型, 研究了CO2在HCOO 修饰Cu(100)表面的吸附行为. 计算结果表明, 与清洁Cu(100)表面相比较, CO2在HCOO修饰的Cu(100)表面的吸附强度增强, 其线性对称性不存在. 究其原因可归结为HCOO的存在使CO2分子带有部分极性, 从而使其与Cu(100)表面的作用增强.     

MBOHO calculations of phosphorus-carbon nuclear spin-spin coupling constants

Summary The novel generalized correlation of the nuclear spin-spin coupling constants with the atomic hybrids and net charges is employed to give a new relationship for calculating the directly bonded phosphorus-carbon coupling constants by use of the maximum bond order hybrid orbital procedure together with the extended Hückel molecular orbital calculation. The calculated coupling constants of phosphorus-carbon are all in good agreement with the experimental data, which shows that the new relationship obtained in the present paper is quite satisfactory for calculation of the phosphorus-carbon coupling constants.The project was supported by the National Natural Science Foundation of China and the Excellent University Teacher's Foundation of State Education Commission of China     

阿托伐他汀钙与牛血清白蛋白的相互作用

采用电化学方法并结合紫外、红外光谱分析, 研究了近生理pH 实验条件下新型抗血脂紊乱药物阿托伐他汀钙(AC)与牛血清白蛋白(BSA)的相互作用, 探讨了BSA对AC峰电流的增敏和减敏效应. 实验发现, 在pH为7.17的NaH₂PO₄-Na₂HPO₄缓冲溶液中, AC在静汞电极上产生一个还原峰, 加入BSA后峰电位发生移动且峰电流发生变化. 电化学研究结果表明, 部分疏水性AC小分子的芳香基团通过疏水作用镶嵌到BSA疏水微区内部, 使AC与BSA之间通过疏水作用力形成一种1:1的结合物, 结合常数为1.67×10⁵. 紫外吸收光谱结果表明,AC的加入使BSA的紫外吸收峰发生红移且有减色效应, 导致BSA 构象改变、α-螺旋含量减小. 红外光谱结果显示, AC与BSA分子中氨基酸残基的硫及氮原子形成键合作用.