β－环糊精包结几种萘衍生物的圆二色性的研究

本文报道了β－环糊精分别包结α－萘胺、β－萘胺、α－萘乙酸的圆二色谱及紫外吸收光谱，并利用ＫＡＪＴＡＲ扇形规则，根据所测得的Ｃｏｔｔｏｎ效应符号和各向异性因子确定了客体分子在环糊精空腔中的取向。同时关联了圆二色谱客体分子在环糊精中的取向和量子计算的矢量矩方向之间的关系，并对量子计算的矢量矩方向的结果给予了定性检验。     

法拉第参数对几种四苯基卟啉金属络合物MCD谱的影响

本文测量了四苯基卟啉铁（ＦｅＴＰＰＣｌ），四苯基卟啉钴（ＣｏＴＰＰ）和四苯基卟啉镍（ＮｉＴＰＰ）的紫外可见吸收光谱和磁圆二色谱（ＭＣＤ），讨论了法拉第参数Ａ，Ｂ两项对Ｓｏｒｅｔ带和Ｑ带的综合影响。发现Ｂ项有参与且使ＭＣＤ谱中Ａ项的Ｓ曲线与波长λ轴交点的跃迁波长值较紫外可见光谱有红移和蓝移的特征。     

The continuum disordered pinning model

Any renewal processes on \({\mathbb {N}}_0\) with a polynomial tail, with exponent \(\alpha \in (0,1)\), has a non-trivial scaling limit, known as the \(\alpha \)-stable regenerative set. In this paper we consider Gibbs transformations of such renewal processes in an i.i.d. random environment, called disordered pinning models. We show that for \(\alpha \in \left( \frac{1}{2}, 1\right) \) these models have a universal scaling limit, which we call the continuum disordered pinning model (CDPM). This is a random closed subset of \({\mathbb {R}}\) in a white noise random environment, with subtle features:

• Any fixed a.s. property of the \(\alpha \)-stable regenerative set (e.g., its Hausdorff dimension) is also an a.s. property of the CDPM, for almost every realization of the environment.
• Nonetheless, the law of the CDPM is singular with respect to the law of the \(\alpha \)-stable regenerative set, for almost every realization of the environment.

The existence of a disordered continuum model, such as the CDPM, is a manifestation of disorder relevance for pinning models with \(\alpha \in \left( \frac{1}{2}, 1\right) \).

     

CO分子振转光谱的理论研究

采用从头算的多参考组态相互作用(MRCI)方法并结合基组aug-cc-pCVQZ计算了CO分子基态(X1Σ+)的势能曲线和偶极矩曲线,得到的势能曲线、偶极矩曲线分别与RKR势、文献的偶极矩曲线吻合较好。利用所得的势能,求解双原子分子核运动的Schrdinger方程找到了CO分子X1Σ+态转动量子数J=0时的70个振动态,对于每一振动态,分别计算了其振动能级G(v)、转动惯性常数B_v和离心畸变常数D_v,并把计算结果与已知的42个实验值做了详细比较,结果表明,计算的振动能级G(v)、转动惯性常数B_v、离心畸变常数D_v与实验值符合较好。利用G(v),B_v导出的光谱常数[谐振频率ω_e(2 160.1 cm-1)、非谐振频率ω_eχ_e(13.1 cm-1)、转动常数B_e(1.918 cm-1)、振转耦合常数α_e(0.017 3 cm-1)]也与实验值的光谱常数[ω_e(2 169.8 cm-1),ω_eχ_e(13.3 cm-1),B_e(1.931 cm-1),α_e(0.017 5 cm-1)]较为符合,这在一定程度上证明了方法MRCI/Aug-cc-pCVQZ对CO分子基态性质的计算是合适而可靠的。利用乘积近似方法计算了CO分子在常温、中温、高温时的配分函数,在此基础上,计算了CO分子在T=296 K时的1-0跃迁带的谱线强度,通过比较发现,计算所得的线强度与HITRAN数据库符合较好。进一步计算的CO分子X1Σ+态1-0,2-0,3-0,4-0,2-1,3-1和4-1跃迁带的带强度也与实验值较为吻合,同时首次计算了CO分子X1Σ+态3-2跃迁带、4-2跃迁带的线强度及带强度。     

含硝基烷基的一些CHNO多硝基化合物的C-NO2键离解能计算——应用于撞击感度

用密度泛函方法,在B3LYP/6-31G*水平对五个含硝基烷基的硝基芳香族炸药分子和四个含硝基烷基的苯酸酯炸药分子进行了几何结构全优化、能量和频率计算.并分别对这两类炸药分子苯环上的C-NO2和烷基上的C-NO2键离解能进行了同等水平的计算.结果表明,这两类分子中的最弱键均是烷基上的C-NO2键.进一步分析实验撞击感度与分子中最弱键离解能量的关系.结果表明,最弱键离解能BDE是表征炸药撞击感度的重要指针,但不是唯一指针.除了BDE,炸药的撞击感度可能还受其它因素或反应途径的影响.     

间接分光光度法测定还原型谷胱甘肽

利用Fe3+-邻菲罗啉混合液为显色剂,以间接光度法测定还原型谷胱甘肽。在pH 4.0的HAc-NaAc缓冲溶液中,Fe3+-邻菲罗啉-谷胱甘肽体系显色反应的最大吸收波长为490 nm,表观摩尔吸光系数为3.93×103L/(mol.cm),吸光度与还原型谷胱甘肽的含量在0~28 mg/L内线性关系良好。该方法用于两份合成样品中还原型谷胱甘肽含量的测定,回收率分别为99.8%、103.5%。     

First-Principles Study of Structural,Elastic and Electronic Properties of OsSi

First-principles study of structural, elastic, and electronic properties of the B20 structure OsSi has been reported using the plane-wave pseudopotential density functional theory method. The calculated equilibrium lattice and elastic constants are in good agreement with the experimental data and other theoretical results. The dependence of the elastic constants, the aggregate elastic modulus, the deviation from the Cauchy relation, the elastic wavevelocities in different directions and the elastic anisotropy on pressure have been obtained and discussed. This could be the first quantitative theoretical prediction of the elastic properties under high pressure of OsSi compound. Moreover, the electronic structure calculations show that OsSi is a degenerate semiconductor with the gap value of 0.68 eV, which is higher than theexperimental value of 0.26 eV. The analysis of the PDOS reveals that hybridization between Os d and Si p states indicates a certain covalency of the Os-Si bonds.     

弛豫铁电单晶的多功能特性及其器件应用

以Pb(Mg1/3 Nb2/3)O3-PbTiO3(PMN-PT或PMNT)为代表的弛豫铁电单晶具有远高于常用锆钛酸铅Pb(Zrx Ti1-x)O3(PZT)陶瓷的压电性能,引起了基于新一代压电单晶的功能器件研究热潮.本研究团队在国际上率先利用Bridgman方法生长出了大尺寸、高质量PMN-PT等弛豫铁电单晶(d33...     

Donor and Ring-Fusing Engineering for Far-Red to Near-Infrared Triphenylpyrylium Fluorophores with Enhanced Fluorescence Performance for Sensing and Imaging

Fluorescent probes have become an indispensable tool in the detection and imaging of biological and disease-related analytes due to their sensitivity and technical simplicity. In particular, fluorescent probes with far-red to near-infrared (FR-NIR) emissions are very attractive for biomedical applications. However, many available FR-NIR fluorophores suffer from small Stokes shifts and sometimes low quantum yields, resulting in self-quenching and low contrast. In this work, we describe the rational design and engineering of FR-NIR 2,4,6-triphenylpyrylium-based fluorophores ( TPP-Fluors ) with the help of theoretical calculations. Our strategy is based on the appending of electron-donating substituents and fusing groups onto 2,4,6-triphenylpyrylium. In contrast to the parent TPP with short emission wavelength, weak quantum yields, and low chemical stability, the obtained novel TPP-Fluors display some favorable properties, such as long-wavelength emission, large Stokes shifts, moderate to high quantum yields, and chemical stability. TPP-Fluors demonstrate their biological value as mitochondria-specific labeling reagents due to their inherently positive nature. In addition, TPP-Fluors can also be applied to develop ratiometric fluorescent probes, as the electron-donating ability of the 2,6-phenyl substituents is closely correlated with their emission wavelength. A proof-of-concept ratiometric probe has been developed by derivatizing the amino groups of TPP-Fluor for the detection and imaging of nitroreductase in vitro and in hypoxic cells.