Double folding model calculation applied to fusion reactions

The interaction potential between a spherical and a deformed nucleus is calculated within the double-folding model for deformed nuclei. We solve the double folding potential numerically by using the truncated multipole expansion method. The shape, separation and orientation dependence of the interaction potential, fusion cross section and barrier distribution of the system ¹⁶O+¹⁵⁴Sm are investigated by considering the quadrupole and hexadecapole deformations of ¹⁵⁴Sm. It is shown that the height and the position of the barrier depend strongly on the deformation and the orientation angles of the deformed nucleus. These are quite important quantities for heavy-ion fusion reactions, and hence produce great effects on the fusion cross section and barrier distribution.     

绿色化学与创造性教学

绿色化学的创造性教学具有现实的可行性和必要性,且绿色化学与创造性教学存在着很好的结合点。探讨了在绿色化学教学中贯彻创造性教学的原则和方式及其对培养高素质有创造性人才的意义。     

双时间步方法的应用分析

对双时间步方法隐式迭代的稳定性、启动问题、子迭代初值和收敛性准则进行分析.一般认为,双时间步的真实时间步长是基于精度,而不是稳定性的基础上给定,因此真实时间步长可以取得很大,但对VonNeumann稳定性分析表明,对于子迭代采用隐式的算法,稳定性的要求对真实时间步有限制.并通过对Sod激波管问题的计算,验证该分析.     

M（Ⅱ）（ArP）~（2－）与核酸碱基（腺嘌呤，胞嘧啶）三元混配配合物稳定性研究

用ｐＨ电位滴定法测定了金属离子（Ｍ~（２＋）＝Ｃｕ~（２＋），Ｃｏ~（２＋），Ｎｉ~（２＋），Ｚｎ~（２＋），Ｃｄ~（２＋）与核酸碱基（Ｌ＝腺嘌呤，胞嘧啶）形成的二元配合物以及与腺昔－５’－三磷酸（ＡＴＰ）形成的三元混配配合物的稳定常数。三元配合物相对于二元配合物的稳定性用平衡常数表示。结果表明：ΔｌｇＫ_ｍ比咪唑或氨的相应配合物ΔｌｇＫ_ｍ大，这可能与三元混配配合物分子内存在配体间的芳环堆积、氢键作用以及π_Ａ－π_Ｂ协同效应有关。     

测定克喘素免疫偶合物分子结合摩尔比的紫外-可见分光光度法

以牛血清白蛋白（BSA）、卵清白蛋白（OVA）为载体，采用重氮法，制出克喘素（CL）的两种免疫偶合物免疫原CL－BSA和包被抗原CL－OVA；通过紫外光谱定性证明偶合物偶联成功，通过可见光谱法定量测定偶合物的分子结合摩尔比，结果表明CL－BSA与CL－OVA的分子结合摩尔比分别为13．19：1、7．53：1，方法简便快捷，灵敏度高。     

银氧相互作用对表面非线性光学效应的贡献

本文讨论氧吸附银表面的非线性光学效应,以及在超高真空环境下所作的实验研究。银氧之间的电子交换使得表面二次谐波信号发生变化。由分子氧在银表面吸附动力学过程的二次谐波测量可推测氧的满π轨道向银反馈的电子数多于银向氧π^*反键轨道输运的电子数,测量了氧在银表面的温度解离过程,且能用一简单的理论模型加以解释。 关键词：     

Electronic structure of tubular aromatic molecules derived from the metallic (5,5) armchair single wall carbon nanotube

All-electron static and time-dependent DFT electronic calculations, with complete geometrical optimization, are performed on tubular molecules up to C(210)H(20) that are finite sections of the (5,5) metallic single wall carbon nanotube with hydrogen termination at the open ends. We find pronounced C-C bond reconstruction at the tube ends; this initiates bond alternation that propagates into the tube centers. For the especially low band gap molecules C(120)H(20), C(150)H(20), and C(180)H(20), alternation increases, and a second nearly isoenergic structural isomer of different alternation is found. A small residual C-C bond alternation and band gap may be present in the infinite tube. The van Hove band gap forms quickly with length, while the metallic Fermi point (at the crossing of linear bands) forms very slowly with length. There are no end-localized states at energies near the Fermi energy. The HOMO-LUMO gap and the lowest singlet excited state, whose energies show a periodicity with length as previously calculated, are optically forbidden. However, each molecule shows an intense visible "charge transfer" transition, not present in the infinite tube, whose energy varies smoothly with length; this transition should be an identifying signature for these molecules. The static axial polarizability per unit length increases rapidly with N as the "charge transfer" transition moves into the infrared; this indicates increasing metallic character. However, the ionization potential, electron affinity, chemical hardness, and relative energetic stability all show the length periodicity seen in the HOMO-LUMO gap, in contrast to the optical "charge transfer" transition and the static axial polarizability. These periodicities, due to a one-dimensional quantum size effect as originally modeled by Coulson in 1938, nevertheless cancel in the calculated Fermi energy, which varies smoothly toward a predicted bulk work function near 3.9 eV. A detailed study of C(190)H(20) with up to eight extra electrons or holes shows the total energy is closely fit by a simple classical charging model, as is commonly applied to metallic clusters.     

Local-global double algebras for slow H{infty} adaptation; the case of l2 disturbances

In this paper, a common algebraic framework is described forthe frozen-time analysis of stability and H optimization inslowly time-varying systems, based on the notion of a normedalgebra on which local and global products are defined. Relationsbetween local stability, local (near) optimality. local coprimefactorization, and global versions of these properties are sought.The framework is valid for time-domain disturbances in l² (Z)^R. The first part of the paper elaborates the double-algebra conceptfor Volterra operators which approximately commute with theshift. The main algebraic properties and norm inequalities aresummarized. Local conditions for global inveribility are obtained.Classical frozen-time stability conditions are incorporatedin relations between local and global spectra. The paper continuesby establishing an explicit formula linking global and localsensitivity for systems with stable plants, where local sensitivityis a Lipschitz continuous function of data. Frequency-domainestimates of time-domain sensitivity norms. which become accurateas rates of time-variation approach zero, are obtained. Notionsof adaptive versus nonadaptive (robust) control are introduced.It is shown that adaptive control can achieve better sensitivitythan optimal nonadaptive control. It is demonstrated by an examplethat, in general, H-optimal interpolants do not depend Lipschitz-continuouslyon data. However, -suboptimal interpolants of the AAK central(maximal entropy) type are shown to satisfy a tractable Lipschitzcondition.     

Tuning intermolecular attraction to create polar order and one-dimensional nanostructures on surfaces

This study utilizes atomic force microscopy and electrostatic force microscopy to investigate the orientation of overcrowded aromatics in films with submonolayer coverage. The results demonstrate that the side chains in the molecules can be used as a tool to control the molecular order and orientation in thin films. For molecules that do not self-associate well, the interaction with the substrate dominates, and the molecules orient with their aromatic planes parallel to the surface. These monolayers have measurable polar order. For molecules that self-associate well, the opposite orientation is observed. These films are comprised of isolated stacks of molecules parallel to the surface.