脂肪族氨基酸二肽与水团簇的理论研究

用ABEEMσπ/MM模型和MP2/6-31+G(d)//B3LYP/6-31G(d)方法研究水合效应对脂肪族氨基酸二肽的影响.从结构和能量两方面说明Leu残基在蛋白质中起成旋作用,Val和Ⅱe残基在蛋白质中起解旋作用.同时得出:水分子严重影响了二肽分子的骨架二面角;对于结合相同数目水分子的团簇倾向于形成含有环状氢键的结构,并且含有环状氢键团簇的结合能大于含有链状氢键团簇的结合能.     

一个被席夫碱配体支撑的一维梯形水簇Bpcmda·4H2O的合成和表征

合成了化合物Bpcmda·4H2O,利用IR、元素分析、^1H NMR和单晶X-射线衍射进行了表征。详细的结构分析表明Bpcmda·4H2O中的溶剂水分子以O-H…O氢键的相互作用形成了一个沿着b轴伸展的独一无二的梯形水簇。     

密度泛函研究双核Mn^Ⅱ取代的杂多酸[Mn2^Ⅱ（X^n＋Mo9O^33）2]2^（n-10）-（X=P^Ⅴ,As^Ⅴ,Se^Ⅵ）的磁耦合交换作用

运用密度泛函理论结合对称性破缺方法（DFT-BS）研究了双锰取代的三明治型多酸阴离子[Mn2^Ⅱ（X^n＋Mo9O^33）2]2^（n-10）-（X=P^Ⅴ,As^Ⅴ,Se^Ⅵ）的磁交换作用.计算得到的磁交换耦合常数（J）为负值,表明在这类体系中存在反铁磁交换作用;进一步从几何,自旋密度分布和前线轨道组成方面分析了中心杂原子X对磁交换耦合的影响,结果表明随着随着中心杂原子X的改变（P^V–As^V–Se^V）,影响到中心双核锰和桥氧构成的磁簇的结构,Mn1…Mn2距离有所增大,Ob…Ob距离有所缩短,从而减弱了超交换途径的有效性,反铁磁耦合常数J的数值依次减小.     

On the structure of graded <Emphasis Type="Italic">λ</Emphasis>-Hopf algebras

Let G be an abelian group, B the G-graded λ-Hopf algebra with A being a bicharacter on G. By introducing some new twisted algebras （coalgebras）, we investigate the basic properties of the graded antipode and the structure for B. We also prove that a G-graded λ-Hopf algebra can be embedded in a usual Hopf algebra. As an application, it is given that if G is a finite abelian group then the graded antipode of a finite dimensional G-graded A-Hopf algebra is invertible.     

Au25纳米团簇合成与应用研究进展

综述了新型金属纳米材料Au25纳米团簇的合成机理和合成工艺改进,结合Au纳米团簇荧光作用机理说明其特有的荧光特性,利用Au纳米团簇荧光性质在离子检测、生物小分子检测、蛋白质检测和生物成像方面的应用,为Au纳米团簇的研究提供参考。     

Teleportation Capability of Six-Qubit Cluster State

Recently Wei-Bo Gao et al. [Phys. Rev. Lett. 104 （2010） 020501]; reported on the creation of a 4-photon 6-qubit cluster state. It is shown this states can be utilized for perfect teleportation of arbitrary three qubit systems and controlled teleportation of an arbitrary two-qubit state. Therefore, the six-qubit cluster state as quantum channels is equivalent to that of maximally six-qubit entangled state.     

布朗扩散系数对胶体聚集粒子簇大小动态标度影响的MonteC …

通过对胶体扩散控制聚集机理的ＭｏｎｔｅＣａｒｌｏ模拟，表明粒子簇的布朗扩散系数与其大小和形状有关，粒子簇的大小分布可被标度、在微观或介观的层次上，揭示了表征粒子簇结构的几何形状因子在扩散控制聚集过程中对动态标度和粒子簇分布的影响。     

Cooling-induced increase of methane cluster size investigated under a Coulomb explosion scheme

In this letter, we discuss the increase in the average cluster size by lowering the stagnation temperature of the methane （CH4） gas. The Coulomb explosion experiments are conducted to estimate the cluster size and the size distribution. The average CH4 cluster sizes Nay of 6 230 and 6 580 are acquired with the source conditions of 30 bars at 240 K and 60 bars at 296 K, respectively. Empirical estimation suggests a five-fold increase in the average size of the CH4 clusters at 240 K compared with that at room temperature under a backing pressure of 30 bars. A strong nonlinear Hagena parameter relation （Г^＊∝ T0^-3.3） for the CH4 clusters is revealed. The results may be favorable for the production of large-sized clusters by using gases at low temperature and high back pressures.