Adlayer structures of aza- and/or oxo-bridged calix[2]arene[2]triazines on Au(111) investigated by scanning tunneling microscopy (STM)

The adlayers formed by a series of aza- and/or oxo-bridged calix[2]arene[2]triazines on Au(111) surfaces were investigated by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. 1,3-Alternate configurations of these molecules are preserved on gold surfaces as in their three-dimensional crystals. STM images show that the cavity sizes of these molecules are finely tuned by substituting the bridging nitrogen atom with oxygen atoms, which change the strengths and densities of the intermolecular hydrogen bonds. Hydrogen bond interaction influences the molecular orientation and conformation in the adlayers, and it plays a key role in the formation of these two-dimensional supramolecular architectures. Coadsorption of calix[2]arene[2]triazine with 1,3,5-tris(5-carboxyamyloxy)benzene (TCAB) intervenes with the intermolecular hydrogen bond formations among the calix[2]arene[2]triazine molecules and consequently causes a conformational transition of the calixarene molecules from rhombic to square. These results demonstrate the role of hydrogen bonds in molecular assembly formations.     

高温超导微带线的传输特性和设计考虑

利用唯象损耗等效法和宏观唯象模型来分析高温超导微带传输线的传输特性。宏观唯象模型克服了传统二流体模型不适用于高温超导体的缺点,使计算结果符合测量值。本文给出了高温超导体YBCO微带传输线的传输特性计算结果,可见其衰减及色散都很小。因此结合唯像损耗等效法和宏观唯象模型可以使高温超导微带线的设计精度有很大提高。     

ASYMMETRY PARAMETERS AND DIFFERENTIAL CROSS SECTIONS FOR PHOTOIONIZATION-EXCITATION OF HELIUM

Asymmetry parameter β₂ for photoionization of helium leaving the He⁺ ion in the n=2 level and differential cross sections(DCSs) in the n=2,3,4 levels with photon emission angle θ=90⁰ are provided at photon energies 69-76.8 eV employing the R-matrix method with a 20-term target representation, in which five polarization orbitals \bar{6}l are included. The asymmetry parameter β₂ and the DCS, in the n=2 level in the region of 69-73 eV, are in good agreement with available experimental and theoretical results. Above the n=3 threshold, we present new theoretical results along with measurements. No theoretical and experimental results can be used to compare with the present calculations of the DCSs for photoionization into the He⁺ ion in the n=3,4 levels.     

高蛋白食物—螺旋藻

螺旋藻为原核生物。其所含蛋白质的质量和数量均为植物世界之冠;尚含各种维生素和生长因子;细胞壁易被人体消化;风味可口;无毒性。     

直接键连原子间的NMR偶合常数的自然杂化轨道研究V.13C-13C和13C-31P核自旋偶合常数1JCC和1JCP

在前文工作的基础上,结合MNDO/EHMO分子轨道方法和自然杂化轨道方法,具体计算了C-C键和C-P键的核自旋偶合常数.计算结果表明,¹J_CC和¹J_CP主要由成键原子的轨道杂化作用和键极性这两种结构因素所决定.为从简单价键理论角度解释和计算¹J_CC和¹J_CP值提供了简便直观的方法.     

微波脉冲与圆柱腔体耦合的时域有限差分模拟

给出了微波脉冲与腔体上孔洞线性耦合的物理模型,讨论了数值模拟的时域有限差分方法以及吸收边界条件,计算了不同大小和位置孔洞的耦合过程,分析了耦合对孔洞大小和入射场偏振方向的依赖关系.     

弹性平面扇形域问题及哈密顿体系*

通过变量代换及变分原理,将平面弹性扇形域的方程导向哈密顿体系,从而可用分离变量法、本征函数展开等方法求解扇形域的分析单元,这样便可以与有限元的程序系统相结合。显示了哈密顿体系、辛数学的应用潜力。     

滴汞电极2.5次微分电分析法测定天然水中痕量钛

天然水中钛的定量分析有分光光度法、极谱法、催化波法等方法。微分电分析法尚未见报导。本文得出了以0.02M苦杏仁酸-4%氯酸钾(pH=3)为底液时,钛在滴汞电极上2.5次微分电分析法催化波,峰形明晰、干扰少、线性范围为1×10^-10-1×10^-7g/ml钛。可直接用于天然水中痕量钛的测定。     

甲基三氢集团的研究

本文通过FT-IR,溶解热和从头计算分子轨道法,对含三氢集团的分子(丙酮、乙酸甲酯、二甲基亚砜等)分子间的相互作用做了研究。在所研究的体系中,计算表明在甲基3个氢原子的中心方向有一个正电势区。它导致负电集团红外吸收带频率位移,溶解热的数据进一步说明三氢集团的集体效应。     

“前三末一”(QSMY)汉字输入法

本文提出了汉字输入法优劣的评价标准,论述了汉字构造和编码的关系,介绍了“前三末一”(QSMY)输入法十项处理技术和方案特点及主要技术指标。