过渡金属偶氮苯衍生物二阶非线性光学性质的密度泛函理论研究

采用含时密度泛函理论方法(TDDFT)计算了IB族过渡金属及第5周期的金属杂化偶氮苯生色团的二阶非线性光学极化率。研究了金属杂化偶氮苯生色团的电子激发跃迁。结果表明, 与金属离子络合后的杂化偶氮苯生色团, 二阶非线性光学极化率明显改变, 是金属的推拉电子效应的结果。IB族金属的在原有机偶氮苯共轭体系的电荷转移方向的强拉电子效应, 增大了电荷转移范围, 使二阶非线性光学极化率增大。与Nb络合的杂化生色团, 沿原电荷转移相反的方向拉动电荷, 电荷转移跃迁局限于金属离子附近, 未能产生大的激发跃迁偶极矩, 体系的二阶非线性光学响应因而降低。激发跃迁能量是另一个主要影响因素, 同一类跃迁中, 金属杂化生色团的跃迁能量越低, 其二阶非线性光学响应就越大。络合Rh的生色团与Nb杂化生色团类似, 电荷转移跃迁范围都比较小, 同时由于Rh与羧基结合时几乎垂直羧基平面, 电荷同时沿X, Y方向转移跃迁, 属于二维电荷转移类型。     

声学微结构的微流控声场的改进与优化*

受限于加工工艺,目前多数的声表面波微流控芯片,主要依靠普通的直通道调节细胞流速,从而控制微球在通道中的排列。但其形成的声场通常无法满足低能量、多功能的微流控需要。本文在普通声表面波微流控芯片的基础上,分别在频域和时域内构建声学微结构,并改变微结构阵列中铜柱间距,模拟仿真了微流控芯片输出端的电势,发现其输出端电压得到了明显的改善。当输入电信号频率在0-30MHz时,输出端电势增加约0.25V;在0-1000ns内,输出端电势增加0.015V左右;进而可以探索开发性价比更高的声波微流控芯片,针对病理检测等所存在的问题进行分析优化,提出新的细胞分离等技术。     

TDDFT Study on the Electronic Excitations and First Hyperpolarizabilities of Mixed-metal Carbonyl Clusters W2Ir2（μ-L）（CO）8（η^5-C5H4Me）2（L = dppe/dppf）

Mixed-metal carbonyl clusters of W2Ir2（CO）10（η^5-C5H4Me）2 1 and W2Ir2（μ-L）（CO）8（η^5-C5H4Me）2 （L = dppe 2, dppf 3） have been studied by TDDFT method focusing on their electronic and nonlinear optical properties. These three clusters exhibit the first static hyperpolarizabilities of medium magnitude （βtot-10×10^-30 esu）. The origin of β is discussed by the new proposed orbital-pair decomposition scheme by Barandes et al. The result suggests that the β values of the two clusters are mainly originated from d-d electron transition within the metal skeleton, and d-p （π＊） electron transition from metals to carbonyls and phenyl. The additional coordination by the electron donor group, ferrocene, makes cluster 3 own much larger β values, and the relatively longer range charge transfer from d orbitals of ferrocene to d orbirals of Ir and W is responsible for the enhanced β values.     

三核欠完整立方烷金属原子簇二阶非线性光学性质的理论研究

研究了具有欠完整立方烷构型的过渡金属原子簇分子的二阶非线性光学性质。利用TDDFT方法计算了选取的簇分子及相应模拟构造分子的静态和动态的一阶非线性光学超级化率(ijk);并计算了不同金属、桥原子和配体以及簇芯对该类化合物一阶超级化率的影响。选取其中的一个簇分子为基本模型,分析了该分子的电子结构和分子轨道,在微观水平上阐述了其非线性光学性质的可能起源。认为由过渡金属和硫原子组成的簇芯和与桥原子相连的配体对该类簇合物的二阶非线性光学性质的起决定性的作用。     

Ultra-incompressible Ternary Diborides Re_（0.5）Ir_（0.5）B_2,Re_（0.5）Tc_（0.5）B_2,Os_（0.5）W_（0.5）B_2 and Os_（0.5）Ru_（0.5）B_2：Density Functional Calculation

In this paper, density functional computations have been applied to the structural, elastic and electronic properties of ternary transition metal diborides Re0.5Ir0.5B2, Re0.5Tc0.5B2, Os0.5W0.5B2 and Os0.5Ru0.5B2 in hexagonal (P63/mmc) and orthorhombic (Pmmn) structures with both local density approximation and generalized gradient approximation. LDA gives smaller lattice parameters and larger elastic moduli than GGA. Both results show that the hexagonal ones are more stable than orthorhombic ones except Os0.5Ru0.5B2. Moreover, the hexagonal structure has superior elastic property than orthorhombic one. Generally speaking, the calculated elastic moduli of Re0.5Ir0.5B2 and Os0.5Ru0.5B2 are smaller than those values of Re0.5Tc0.5B2 and Os0.5W0.5B2 within the same structure because of the filling of antibonding states. The relativistic effects result in weaker bonds of Tc-B (Ru-B) than those of Re-B (Os-B). All the diborides are ultra-incompressible. Re0.5Tc0.5B2 has the largest shear modulus and it is a promising superhard diboride like Os0.5W0.5B2. The elastic properties are in high correlation with the bond strength. The shear moduli are more sensitive than the bulk moduli to the bond strength.     

可交换随机变量序列的完全收敛性

本文探讨了可交换随机变量的完全收敛性问题，从充性和必要性两方面都作了研究，并把ｉ．ｉ．ｄ．情形下的部分结果作了为特例推出。     

Ligand-controlled First Hyperpolarizabilities of a Series of Tetrahedral Iridium Clusters Ir4（CO）9L： a TDDFT Study

A series of tetrahedral iridium carbonyl clusters coordinated by systematically varied series of ligands have been studied by TDDFT method focusing on their electronic and non- linear optical properties. The clusters of Ir4（CO）12 （1）, Ir4（μ-CO）3（CO）9 （2）, Ir4（μ-L）（CO）10 （L = dppm 3, dppe 4, （Ph2P）2CHMe 5, Ph2P（CH2）3PPh2 6） and Ir4（CO）10（phen） （phen = 1,10-phen- anthroline） （7） exhibit the first static hyperpolarizabilities of medium magnitude （βtot-10×10^-30 esu）. The second order nonlinear optical response of the seven clusters increase from 0 to 23 ×10^-30 esu; the high symmetric cluster Ir4（CO）12 debases its symmetry and presents the second order nonlinear optical behavior as the coordination style of some carbonyls changes to bridge style, and then the response increases regularly with the systematical variation of the ligands. The origination of the first hyperpolarizability is discussed by the expanded orbital decomposition scheme. The results suggest the d-d electron transition from the apical iridium atom to the other three Ir atoms inside the metal skeleton, and d-πelectron transitions from metals to carbonyls are responsible for the first hyperpolarizabilities. Particularly, for cluster 7, the charge transfer from d orbitals of iridium to π＊ orbirals of phenanthroline originates the first hyperpolarizabilities.     

基于TPB模型的学术创业意向影响因素研究

在知识型社会的背景之下,大学作为生产、传播、应用知识的组织,开始在社会与经济中发挥越来越大的作用。本文首先介绍了学术创业研究二十多年来的主要思想、研究方法与研究成果,并指出了现有研究的不足。随后,结合创业意向领域的现有研究,在传统的计划行为理论基础上进一步发展,探索近端预测因子和远端预测因子在学术创业意向模型中的影响作用。收集了105名受访学者数据,并使用偏最小二乘结构方程模型方法来检验所提出的理论模型假设,剖析了拥有能力感知和外部环境感知与TPB模型原有结构(即个人态度、主观规范、知觉行为控制和创业意向)之间的潜在影响关系。研究结果揭示了各因素之间的显著与非显著路径关系,以及直接与间接影响效果。     

无机-有机杂化非线性光学晶体材料LAP和d-LAP晶体红外吸收边计算

根据双原子谐振子模型近似,提出了估算分子晶体材料红外吸收边的理论方法,然后利用超分子量子化学从头算,计算了L-精氨酸一水磷酸盐(LAP)晶体和氘化L-精氨酸一水磷酸盐(d-LAP)晶体单元超分子的红外振动光谱,其中LAP晶体超分子计算值与晶体红外光谱实验值吻合,表明超分子计算能有效地模拟无机-有机杂化非线性光学晶体的红外振动光谱。在归属了超分子重要基频线后,分析其红外强度,并估算了泛频频率。根据我们提出的方法,估算了这两种晶体的红外吸收边,结果与实验值较吻合。表明我们建议的理论方法是合理的。此外,通过计算表明,如果非线性光学晶体材料的红外吸收边是由与活泼H有关的伸缩振动泛频频率决定,那么活泼H的氘化是一种改善红外吸收边的有效途径。     

一水甲酸锂晶体二阶非线性光学系数的理论计算

采用有限场方法和含时耦合微扰方法,在6-31+G*基组水平上并考虑了电子相关效应和色散效应的影响,计算了一水甲酸锂晶体的宏观二阶非线性光学极化率和二阶非线性光学系数。其中非线性光学系数d31和d32与Roberts报道的相符,而另一个系数d33则比文献值大。计算结果还表明,在非共振情况下,电子相关效应对非线性光学极化率的影响远远超过了色散效应,同时表明Roberts报道的非线性光学系数比Singh等人报道的更为合理。