LUND面积定律产生子在R值测量中的应用

对Lund弦碎裂模型强子化面积定律严格求解,得到e⁺e^－湮没产生少体初始强子态的遍举分布.基于面积定律的新产生子LUARLW在2—5GeV能区的模拟结果与BES数据的多种谱分布符合很好,用于BES上强子产生总截面测量的强子探测效率的估计.     

A Theoretical Study of the Mechanism for the Photodecomposition of AgN3

IntroductionOrganic and inorganic azides have been an extensive investigated subject for manyyears['J. Azide compounds as the energetic materials have also been studied and character-ized[2], however, the kinetic characters have unsufficiently been studied in theory and experi-ment. In the 1930's it was discovered that the slow thermal decomposition of NaN3, KN3,AgNs and Pb(N,)2 was accompanied by very feeb1e 1uminescence, Which has been claimed tobe independent of the cations[3J, and coul…     

Conformation of 1,2-Dimethoxyethane in Water

To understand the conformation of 1,2-dimethoxyethane (DME) in water, a system of two kinds of molecules, DME and H_2O, was focused. The interaction of various conformers of DME with water was studied by means of ab initio molecular orbital calculation with 6-31G (d) basis set. It is shown that there are two forms of interactions between the two molecules in the system, the close touched (H_2O attaches to the two oxygen atoms of DME) and the open touched (H_2O attaches to one oxygen atom of DME) structures. The conformation of DME is remarkably influenced by the interactions. Instead the ttt conformer is preferred in the gas state, with a close touched H_2O the tgt conformer becomes the most stable one. The obtained hydration energies show that the stabilized order of DME conformers by water is tgt>tgg′>ttt.     

DNA修饰电极的研究(ⅠΧ)——DNA探针在金基底上的固定、表征及其表面分子杂交

采用巯基化合物自组装 /共价键合反应的逐层固定方法将双链 DNA固定到金表面得到 DNA修饰电极 ,并对该电极表面进行了电化学和 X射线光电子能谱表征 .研究了电极表面固定化 DNA的表面分子杂交 .对开发电化学基因诊断芯片和基因传感器具有一定意义     

Mechanism of 1,2-shift through p -complex transition state

A systematic calculation of the potential curves or surfaces for 1,2-shift has been realized by using MNDO or other models in MOPAC programs. By referring to the previous authors' viewpoints, the 1,2-shift can be divided into two categories. 1,2-electron-deficient shift is that the electronic configuration of the atom which accepts the migrating group is a cation or an electron- deficient atom, and 1,2-anion shift is the one that the accepted atom of the migration group is a negative ion. In terms of the experimental facts and the calculation of the potential surfaces, in electron-deficient shift such as Beckmann or Baeyer-Villiger rearrangement, the migration occurs through a transition complex formed between the p -bond and the cation or electron-deficient migrating group, but in anion shift such as Wittig or Stevens rearrangement, the electron pair in p -orbit excites at first to p * orbit, and then the migration occurs through the new formed complex between the anion migration group and the vacant p orbit. The above mechanisms explain reasonably the intramolecular properties, the configuration retentions of the migration group, and the corresponding migratory aptitudes of the two type 1,2-shifts. The partial and less important free radical reaction of 1,2-anion shift has been explained by the p -complex mechanism too.     

黏弹性结构振动阻尼等效化方法的讨论

基于能量等效的原则将黏弹性结构振动阻尼等效简化成黏性阻尼模型来处理是工程上常用的方法.本文首先介绍了能量等效法,并提出了一种基于系统特征值相等原则的等效方法;详细讨论并比较了这两种黏性阻尼等效方法所得到的等效系统,指出基于能量、特征值等效的原则实质上分别等价于系统的频率响应函数、频率响应函数幅值的等效性.     

地理信息系统GIS支持下的城市地质环境评价

以 GIS为支撑工具 ,对城市地质环境空间数据库的建立方法、城市建设用地类型的初步划分及城市建设用地与地质环境的协调性评价模型作了分析 ,并选取典型实例进行剖析 ,结果表明 GIS是城市地质环境研究的有效工具。     

互穿网络聚合物的自由体积特性

测量了不同组分比的聚氨酯/丙烯酸酯类树脂(PU/VERH)的化学计量和化学不计量同时互穿网络聚合物SINs(Simultaneous interpenetrating polymer networks)的正电子湮没寿命参数．研究结果表明两种SINs随组分变化存在相转变过程;而且化学计量PU/VERH SIN两组分间存在的较强化学键作用减小SINs平均自由体积孔洞尺寸,分子链段堆砌紧密,分子链段间相互作用增强．从而增强了互穿效果、极大地改善了SINs两组分之间的相溶性,从微观上改善了互穿网络聚合物的力学性能,为分子水平设计新型材料提供了实验依据．     

毛细管气相色谱法测定水溶液中榄香烯哌啶盐的含量

 建立了一种准确测定水溶液中榄香烯哌啶盐含量的方法。样品水溶液经碳酸钠中和 ,并用含正十八烷(内标 )的正庚烷溶液萃取后 ,采用毛细管气相色谱法进行分析。方法的线性范围为 1 0 g/L～ 1 0 0 g/L ,精密度小于 2 % ,平均回收率为 99 96% ,RSD为 0 46% (n =5)。     

超声射流冷却丁二酮的激光诱导荧光激发谱

在超声射流条件下获得了丁二酮在４３２－４５１ｎｍ波段的激光诱导荧光激发谱。在前人标识为０＾００带谱峰的红端观察到３个很弱的谱峰分别位于０,８７,９７ｃｍ＾－１处（以２２１８２ｃｍ＾－１为０ｃｍ＾－１）。在８７和９７ｃｍ＾－１附近精细扫描,观测到８７和９７ｃｍ＾－１谱峰的联道分裂分别为１．０５观和１．６８ｃｍ＾－１,与理论计算的分裂值符合得很好人 而确定了Ｓ１←Ｓ０跃迁０＾００带的位置在２２１８２ｃ