粉防己碱与牛血清白蛋白相互作用的研究

利用荧光光培和紫外-可见吸收光谱,研究了粉防己碱与BSA相瓦作用的光谱学行为.研究结果表明,粉防己碱埘BSA有较强的荧光猝灭作用,静态猝灭和非辐射能量转移是导致粉防己碱猝火BSA内源荧光的主要原因.利用Stern-Volmer方程处理实验数据,获得了猝火常数Ksv,不同温度下的Ksv分别为1.26×104 L·mol-1(300 K),1.17×104 L·mol-1(310 K),1.12×104 L·mol-1(320 K).根据Forster非辐射能量转移理论计算出了粉防己碱与BSA间的结合距离r(300 K:3.24 nm;310 K:3.31 nm;320 K:3.50nm).此外,还求得了粉防己碱与BSA的结合常数KA(300 K:1.52×105 L·mol-1;310 K:2.03×105 L·mol-1;320 K:2.89×105 L·mol-1)及相应温度下的热力学参数,热力学数据表明二者主要靠疏水作用力结合.粉防己碱与BSA相互作用的同步荧光光谱表明,二者的结合对BSA构象产生了影响.     

Band Structures of Ultrathin Bi(110) Films on Black Phosphorus Substrates Using Angle-Resolved Photoemission Spectroscopy

The band structures of two-monolayer Bi(110) films on black phosphorus substrates are studied using angleresolved photoemission spectroscopy. Within the band gap of bulk black phosphorus, the electronic states near the Fermi level are dominated by the Bi(110) film. The band dispersions revealed by our data suggest that the orientation of the Bi(110) film is aligned with the black phosphorus substrate. The electronic structures of the Bi(110) film strongly deviate from the band calculations of the free-standing Bi(110) film, suggesting that the substrate can significantly affect the electronic states in the Bi(110) film. Our data show that there are no non-trivial electronic states in Bi(110) films grown on black phosphorus substrates.     

气相色谱法测定17种有机磷类农药残留

建立了气相色谱(GC)测定粮谷作物和果蔬作物中17种有机磷类农残的方法。本方法对不同基质样品进行针对性的前处理措施,在充分提取的前提下建立合理的色谱方法,通过程序升温及分组测定的方式,成功避免了临近峰的干扰,使用外标法定量。结果表明,在不同基质中,17种有机磷农残在0.01~0.1 mg/L浓度范围内相关系数均在0.997以上,线性关系良好;在高、中、低三个添加水平下,回收率在80.0%~116.7%,相对标准偏差最高为8.48%;方法检出限在果蔬、粮谷基质中分别为0.0559~0.589μg/Kg、0.0547~0.592μg/Kg。本方法快速高效,在1小时内就可以完成从前处理到得到检测结果整个过程,同时灵敏度、准确度、精密度均符合实际农药残留检测的要求。     

Shape co-existence and structural evolution of the Vi13/2 band in 157Yb

The high-spin states of 157Yb have been studied via the reaction of 144Sm(16O, 3n) at 16O energy of 90 MeV using techniques of in-beam γ-ray spectroscopy. Measurement of γ-γ-t coincidences was performed with 11 BGO(AC)HPGe detectors. Based on the γ-γ coincidence relationships and the measured results of γ-ray anisotropies and DCO ratios, the level scheme for 157Yb was established. The shape co-existence and structural evolution of the Vi13/2 band with increasing angular momentum in 157Yb have been discussed. The systematics of the Vi13/2 bands in the N = 87 odd-A isotones have been compared.     

卷弧翼气动特性研究进展

本文列举了卷弧翼在战术武器中的应用实例，介绍了卷弧翼的几何特性、气动特性、优缺点及布局设计，评述了对卷弧翼气动特性所做的理论与试验研究工作。最后指出了有待进一步研究的问题。     

157Yb的形状共存研究

利用在束γ谱学方法,通过反应¹⁴⁴Sm(¹⁶O,3n)¹⁵⁷Yb研究了¹⁵⁷Yb的激发态能级结构.实验中使用的¹⁶O束流能量为90MeV.基于实验得到的γγ符合关系、γ射线的各向异性度和DCO系数,建议了¹⁵⁷Yb的高自旋能级纲图.¹⁵⁷Yb的能级纲图主要由两串跃迁性质明显不同的级联能级组成,它们分别对应于νi_13/2转动带和单粒子激发态.着重讨论了¹⁵⁷Yb的形状共存和νi_13/2转动带随角动量的结构演化.     

苯硝化反应机理及其溶剂效应的理论研究

在密度泛函理论(DFT)非限制B3LYP/6-311G^**水平上, 求得苯与硝酰阳离子(NO₂⁺ )硝化反应势能面上的π-过渡态、σ-过渡态, 以及由这两个过渡态通过内禀反应坐标(IRC)计算所得σ-反应络合物和σ-中间体(Wheland中间体)的全优化几何构型、电子结构、IR光谱和热力学性质, 确认了反应通道, 阐明了在亲电取代过程中无同位素效应的实验事实; 求得气相中反应的活化能为8.370 kJ/mol, 速率常数数量级为10¹⁰ mol^-1·s^-1. 从热力学和动力学两方面阐明了苯硝化的亲电取代机理优于单电子转移双自由基机理. 通过自洽反应场(SCRF)B3LYP/6-311G^**计算, 系统研究了相对介电常数分别为5.0, 25.0, 50.0和78.5的溶剂对苯与NO₂⁺反应过程中各驻点的结构和反应机理的影响, 发现溶剂效应使气相中形成σ-过渡态(速控步骤)的活化能下降, 并使该步骤在水溶液中成为无垒反应. 此外还揭示了实验与理论共同关心的Wheland中间体的电荷分布、偶极矩、前线轨道能级差与溶剂稳定化能之间存在的良好线性关系.     

Theoretical Study on the High Energy Density Compound Hexanitrohexaazatricyclotetradecanedifuroxan

Density functional theory （DFT） has been employed to study the molecular geometries, electronic structures, infrared （IR） spectra, and thermodynamic properties of the high energy density compound hexanitrohexaazatricyclotetradecanedifuroxan （HHTTD） at the B3LYP/6-31G^＊＊ level of theory. The calculated results show that there are four conformational isomers （α, β, γ and δ） for HHTTD, and the relative stabilities of four conformers were assessed based on the calculated total energies and the energy-gaps between the frontier molecular orbitals. The computed harmonic vibrational frequencies are in reasonable agreement with the available experimental data. Thermodynamic properties derived from the IR spectra on the basis of statistical thermodynamic principles are linearly correlated with the temperature. Detonation performances were evaluated by using the Kamlet-Jacobs equations based on the calculated densities and heats of formation. It was found that four HHTTD isomers with the predicted densities of ca. 2 g·cm^-3, detonation velocities near 10 km·s^-1, and detonation pressures over 45 GPa, may be novel potential candidates of high energy density materials （HEDM）. These results may provide basic information for the molecular design of HEDM.     

HNO与O自由基反应的密度泛函理论研究

用密度泛函理论(DFT)和从头算方法，对HNO与O自由基反应进行了研究。在(U)B3LYP/6-311G^**和(U)B3LYP/aug-cc-pVTZ水平下优化了反应通道上各驻点(反应物、中间体、过渡态及产物)的几何构型。在(U)QCISD/aug-cc-pVTZ水平下计算了各物种的单点能，并对总能量进行了零点能校正。研究结果表明，HNO与O自由基反应过程中存在O → N、O → O和O → H进攻的竞争机制，且存在着多条反应通道。采用过渡态理论计算了600～2 000 K温度范围内3条慢反应通道的速率常数。求得lnk和1/T之间的线性关系。3种通道的阿累尼乌斯指前因子分别为1.469 × 10¹⁰、1.22 × 10¹⁰(1.06 × 10¹⁰)和2.26 × 10¹³。     

3-硝基-1,2,4-三唑-5-酮与NH3及H2O分子间相互作用的理论研究

在DFT-B3LYP/6-311＋＋G**水平上, 求得3-硝基-1,2,4-三唑-5-酮(NTO)/NH₃和NTO/H₂O两种超分子体系势能面上5种全优化构型. 经基组叠加误差(BSSE)和零点能(ZPE)校正, 求得NTO与NH₃和H₂O的分子间最大相互作用能依次为－37.58和－30.14 kJ/mol, 表明NTO与NH₃的分子间相互作用强于与H₂O的作用. 超分子体系中电子均由NH₃或H₂O向NTO转移, 相互作用能主要由强氢键所贡献, 由自然键轨道分析揭示了相互作用的本质. 对优化构型进行振动分析, 并基于统计热力学求得200.0～800.0 K温度范围从单体形成超分子的热力学性质变化. 发现由NTO和NH₃形成超分子II和III在常温下可自发进行; 而NTO和H₂O只在低温下才能自发形成IV, V和VI超分子.