密度泛函理论研究5-单苯基卟啉分子的几何结构和拉曼光谱

利用密度泛函理论(DFT)计算了5-单苯基卟啉(H2MPP)的几何结构和拉曼振动频率. 计算表明, 单个次甲基位置上的苯基取代降低了卟啉骨架大环的对称性. 苯基团取代对次甲基位置附近结构的影响较大, 而对吡咯环结构的影响较小. 计算给出的拉曼振动频率(校正因子为0.971)与实验测量数据吻合较好, 均方根误差(RMS)小于6.7 cm-1. 根据理论计算结果对实测拉曼光谱进行了指认, 计算分析和实验观察同时表明, 单个次甲基位置上的苯基取代导致卟啉大环的一些平面内简正振动, 如ν6、ν20、ν24和ν32等简正振动发生分裂. 分析认为其根本原因为单苯基取代导致的卟啉骨架大环对称性的降低.     

新型手性双核Salen Zn(II)配合物的分子识别研究

采用新型Salen中间体合成了新型SalenZn(II)配合物.用紫外-可见光谱滴定法研究了主体双核SalenZn(II)与咪唑、二胺类等含氮小分子的分子识别行为,测定了它们的缔合常数.对咪唑类客体的缔合常数顺序为K(Im)>K(2?MeIm)>K(EMeIm);对二胺类客体缔合常数顺序为K(DAP)>K(DAE).主体与咪唑类和二胺类客体的配位数分别是2和1.主体与这些客体的识别过程为放热、熵减的焓驱动反应.利用圆二色光谱研究了识别过程的Cotton效应.用分子力学方法研究了主客体体系的最低能量构型,通过量化计算对实验事实做了进一步解释.     

4- (4,6-二甲基嘧啶-2-基)-3-硫代脲酸甲酯的合成晶体结构及量子化学研究

4-（4,6-Dimethylpyrimidin-2-yl）-3-thio-allophanic acid methyl ester was synthesized with mixing 2-amino-4,6- dimethylpyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray diffraction measurement were obtained by recrystallization from dimethylformamide at room temperature. The crystal belongs to monoclinic symmetry with space group C2/m, and crystal parameters of a= 1.7537（5） nm, b= 0.6759（2） nm, c=1.1148（3） nm, β=118.557（4）°, V=1.1605（6） nm^3, Z=4, De= 1.375 g/cm^3,μ=0.271 mm^-1, F（000）=504, and 1519 [1〉2σ（I）] observable independent reflections were used for the determination and refmement of the crystal structures with final R1 of 0.0372 and wR2 of 0.0992. The theoretical investigation of the title compound was carried out with DRT-B3LYP/6-311G, HF/6-311G and MP2/6-311G methods, and the atomic net charges and the population were discussed.     

手性不对称Salen Ni对咪唑类和二胺类客体的分子识别研究

用紫外-可见光谱滴定法研究了新型手性不对称Salen Ni主体(1和2)与咪唑类和二胺类客体的分子识别行为. 结果表明, 二胺类客体的缔合常数顺序为Kθ(乙二胺)>Kθ(丙二胺); 咪唑类客体的缔合常数顺序为Kθ(Im)>Kθ(N-MeIm)>Kθ(2-MeIm)>Kθ(2-Et-4-MeIm), 除主体2对2-乙基-4-甲基咪唑的配位数为1外, 其它体系的配位数均为2. 通过测定识别过程的热力学函数ΔrHθm和ΔrSθm发现, 反应为放热、熵减少过程; 利用圆二色光谱研究了识别过程中的主-客体结合能力的强弱; 用分子力学方法研究了主客体体系的最低能量构象, 并通过量化计算对实验事实做了进一步解释.     

Quantum Effect in Mesoscopic Open Electron Resonator

The open electron resonator is a mesoscopic device that has attracted considerable attention due to its remarkable behavior： conductance oscillations. In this paper, using an improved quantum theory to mesoscopic circuits developed recently by Li and Chen, the mesoscopic electron resonator is quantized based on the fundamental fact that the electric charge takes discrete value. With presentation transformation and unitary transformation, the SchrSdinger equation becomes an standard Mathieu equation. Then, the detailed energy spectrum and wave functions in the system axe obtained, which will be helpful to the observation of other characters of electron resonator. The average of currents and square of the current are calculated, the results show the existence of the current fluctuation, which causes the noise in the circuits, the influence of inductance to the noise is discussed. With the results achieved, the stability characters of mesoscopic electron resonator are studied firstly, these works would be benefit to the design and control of integrate circuit.     

基于分子间π-π相互作用形成的吖啶荧光化合物超分子结构及其性能研究

合成了10-甲基-1,2-苯并吖啶（10-Methyl-benzo[1,2]acridine,MBA）,用X射线单晶衍射方法获得了其单晶结构,结构分析结果表明,在MBA晶体中,由于存在分子间π-π相互作用,形成了一维无限伸展的分子柱,用MBA制备了微米晶体,通过调控反应物的浓度可以获得长方和线状的微米晶体,用荧光显微镜考察了微米晶体的形貌,研究了MBA的紫外吸收和荧光发射光谱性质,实验结果表明,MBA是一种具有蓝光发射特点的有机分子。     

Correlation between detrended fluctuation analysis and the Lempel–Ziv complexity in nonlinear time series analysis

We focus on the study of the correlation between the detrended fluctuation analysis (DFA) and the Lempel-Ziv complexity (LZC) in nonlinear time series analysis in this paper. Typical dynamical systems including logistic map and Duffing model are investigated. Moreover, the influences of the Gaussian random noise on both DFA and LZC are analyzed. The results show a high correlation between DFA and LZC, which can quantify the non-stationarity and the nonlinearity of the time series, respectively. With the enhancement of the random component, the exponent α and the normalized complexity index C show increasing trends. In addition, C is found to be more sensitive to the fluctuation in the nonlinear time series than α. Finally, the correlation between DFA and LZC is applied to the feature extraction of vibration signals for a reciprocating compressor gas valve, and an effective fault diagnosis result is obtained.     

Kα波段介质加载回旋行波管小信号分析与设计

应用分析回旋行波管绝对不稳定性的Briggs-Bers相碰判据与小信号色散方程，并结合介质加载波导的冷场分析，通过数值计算比较了不同介质加载条件下回旋行波管工作模式的起振电流与寄生模式的起振长度，通过改变加载介质的特性参数从而增加行波损耗可以显著提高工作模式起振电流，并抑制掉寄生模式的返波振荡.结合介质加载波导冷场分析与回旋行波管小信号色散方程，分析了介质加载条件下回旋行波管小信号增益，给出了不同介质加载条件下的回旋行波管的小信号增益带宽曲线.在对介质回旋行波管自激振荡与小信号增益的综合分析基础上，对Kα     

Theoretical investigation on near-infrared and visible absorption spectra of nanometallic aluminium with oxide coating in nanoenergetic materials: size and shape effects

The effects of metal core dimension, oxide shell thickness and ellipsoid aspect ratio of Al-Al2O3 core-shell nanoparticles on the near-infrared and visible absorption spectra of nanocomposite Al-Al2O3/nitrocellulose（NC） film are investigated by numerical calculations. Both the size-dependent interband transitions and frequency-dependent free electron damping of the nanometallic aluminium are taken into account in the calculations. Oxidation effect of nanoaluminium is also analysed. It is shown that oxidation may enhance but may also reduce the optical absorption, depending on the excited light energy and initial dimension of nanoparticle. Metal core size and excited light energy dominate the absorption characteristic. The absorption ability of ellipsoidal nanoparticles is larger than that of spheroidal nanoparticles and increases by the square index as the aspect ratio increases. These calculations will provide some significant theoretical guidance for the preparation and laser ignition of nanoenergetic materials.     

具有低表面自由能有机介电薄膜的制备及表征

通过自主开发的有机镀膜技术在Mg-Mn-Ce镁合金表面制备了具有低表面自由能和较高介电常数的有机纳米薄膜. 利用X射线光电子能谱(XPS)分析了表面有机镀膜过程的反应机理, 借助傅里叶变换红外(FT-IR)光谱进一步确认表面有机膜层的存在, 采用接触角测量仪测定了有机薄膜的蒸馏水接触角和表面自由能变化, 使用椭圆偏振光谱仪研究了薄膜的厚度, 并借助精密阻抗分析仪评价了薄膜的介电性能. 有机镀膜后镁合金表面形成了一层纳米级厚度的有机薄膜, 接触角从基体的70.8°上升至150.5°, 表面自由能从基体的37.96 mJ·m^-2降低到1.57 mJ·m^-2, 镁合金表面从亲水性转变为疏水性; 薄膜的厚度和质量随有机镀膜时间延长先增加后有所减小, 在镀膜20 min时薄膜性能最佳, 此时膜重达到23.5 μg·cm^-2, 膜厚最大为147.48 nm, 其相对介电常数也达到最大, 在1 kHz下可达24.922.