多组分光谱相关色谱及其在中药色谱指纺图谱分析中的应用

基于正交投影理论和相关色谱方法提出多组分光色谱方法提出多组分光谱相关 色谱。为克服联用色谱仪器的不等性噪声影响，采用目标组分投影前后的光谱夹角 余弦判据，判断不同的中药色谱指纹图谱的相关组分色谱峰簇。该方法为中药指纹 图谱的数据处理、合理评价以及中药谱效学的基本理论研究提供一种实用的工具。     

Synthesis and structural characterization of [Au2Pd14(μ3-CO)7(μ2-CO)2(PMe3)11](PF6)2—An icosahedrally-based high nuclearity mixed metal cluster

[Au₂Pd₁₄(₃-CO)₇(₂-CO)₂(PMe₃)₁₁](PF₆)₂ has been synthesized from [Pd₈(CO)₈(PMe₃)₇] and AuCl(PCy₃) in the presence of TIPF₆. It has been characterised on the basis of mass spectrometry, infrared and NMR spectroscopy, and a single crystal X-ray diffraction study. The structure is based on a palladium-centered Au₂Pd₁₁ icosahedron which shares an edge with a Pd₅ trigonal bipyramid.This paper is dedicated to Larry Dahl on his 65th Birthday—his enthusiasm and achievements in cluster chemistry have inspired us all for more than 30 years.     

Metastable decay rates,asymptotic expansions,and analytic continuation of thermodynamic functions

The grand potentialP(z)/kT of the cluster model at fugacityz, neglecting interactions between clusters, is defined by a power series _n Q _n z ⁿ , whereQ _n , which depends on the temperatureT, is the partition function of a cluster of sizen. At low temperatures this series has a finite radius of convergencez _s . Some theorems are proved showing that ifQ _n , considered as a function ofn, is the Laplace transform of a function with suitable properties, thenP(z) can be analytically continued into the complexz plane cut along the real axis fromz _s to + and that (a) the imaginary part ofP(z) on the cut is (apart from a relatively unimportant prefactor) equal to the rate of nucleation of the corresponding metastable state, as given by Becker-Döring theory, and (b) the real part ofP(z) on the cut is approximately equal to the metastable grand potential as calculated by truncating the divergent power series at its smallest term.     

Uniqueness and clustering properties of Gibbs states for classical and quantum unbounded spin systems

We consider quantum unbounded spin systems (lattice boson systems) in -dimensional lattice space Z. Under appropriate conditions on the interactions we prove that in a region of high temperatures the Gibbs state is unique, is translationally invariant, and has clustering properties. The main methods we use are the Wiener integral representation, the cluster expansions for zero boundary conditions and for general Gibbs state, and explicitly -dependent probability estimates. For one-dimensional systems we show the uniqueness of Gibbs states for any value of temperature by using the method of perturbed states. We also consider classical unbounded spin systems. We derive necessary estimates so that all of the results for the quantum systems hold for the classical systems by straightforward applications of the methods used in the quantum case.     

Virial expansion for a polymer with a realistic pair-potential interaction

No modern theory of polymer excluded volume adequately describes the crossover from poor solvent to good solvent conditions; a fundamental difficulty is a singularity in the binary cluster integral. Mayer expansion techniques are applied to a model with a pair interaction between monomers to clarify the distinction between geometric and solvent contributions to excluded volume. Detailed calculations are undertaken for a hard-core potential and a mimic Lennard-Jones potential. The significance of the singularity in the binary cluster integral for calculations in the crossover regime is discussed.     

The covariance matrix of the Potts model: A random cluster analysis

We consider the covariance matrix,G ^mm =q ²<(_x,m);(_y,m)>, of thed-dimensionalq-states Potts model, rewriting it in the random cluster representation of Fortuin and Kasteleyn. In any of theq ordered phases, we identify the eigenvalues of this matrix both in terms of representations of the unbroken symmetry group of the model and in terms of random cluster connectivities and covariances, thereby attributing algebraic significance to these stochastic geometric quantities. We also show that the correlation length corresponding to the decay rate of one of the eigenvalues is the same as the inverse decay rate of the diameter of finite clusers. For dimensiond=2, we show that this correlation length and the correlation length of the two-point function with free boundary conditions at the corresponding dual temperature are equal up to a factor of two. For systems with first-order transitions, this relation helps to resolve certain inconsistencies between recent exact and numerical work on correlation lengths at the self-dual point _o. For systems with second order transitions, this relation implies the equality of the correlation length exponents from above and below threshold, as well as an amplitude ratio of two. In the course of proving the above results, we establish several properties of independent interest, including left continuity of the inverse correlation length with free boundary conditions and upper semicontinuity of the decay rate for finite clusters in all dimensions, and left continuity of the two-dimensional free boundary condition percolation probability at _o. We also introduce DLR equations for the random cluster model and use them to establish ergodicity of the free measure. In order to prove these results, we introduce a new class of events which we call decoupling events and two inequalities for these events. The first is similar to the FKG inequality, but holds for events which are neither increasing nor decreasing; the second is similar to the van den Berg-Kesten inequality in standard percolation. Both inequalities hold for an arbitrary FKG measure.     

Metastable fluid flow described via a discrete-velocity coagulation-fragmentation model

A discrete-velocity Boltzmann model is introduced. It is based on two principles: (i) clusters of particles move in ³ with seven fixed momenta; (ii) clusters may gain or lose particles according to the rules of Becker-Döring cluster equations. The model provides a kinetic representation of evaporation and condensation. The model is used to obtain macroscopic fluid equations which are valid into the metastable fluid regime, , where is any positive number, is the inelastic Knudsen number, and _s is the saturation density.     

Reactions of Laser Ablation-magnesium Plasma with Methanol Clusters

IntroductionReactions of metal ions with neutral molecules orclusters produce a variety of metal complex ions andother new series of cluster ions including cations andanions.The laser ablation-molecular beam(LA-MB)method has marked its relevance in the st…     

Ester Elimination: A General Solvent Dependent Non-Hydrolytic Route to Metal and Mixed-Metal Oxides

Molecular routes to metal oxides has become an area of intensescientific interest due to the technological relevance of thesematerials. Molecular routes are proving important as a result ofthe possibility to control the physical and chemical propertiesof the final materials.We have chosen to study non-hydrolytic methods, namely esterelimination reactions between two prototypical molecularprecursors metal alkoxides, M(OR)_n, and metal carboxylates, M(O₂CR)_n, to synthesize metal oxides: This method allows for the synthesis of pure metal oxides bycomplete elimination of the organic supporting ligands withconcomitant formation of M-O-M bridges.Furthermore, incomplete esterelimination can lead to isolation of molecular clusters asintermediates which can also be used as building blocks for theformation of metal oxides with controlled microstructure.Here we report a series of reactions between Sn and Si alkoxidesand carboxylates designed to gain further insight into thefactors governing ester elimination reactions. By choosingcompounds with varying coordination environments and stericaccessibility we have devised a set of criteria which shouldallow for successful ester elimination between metal alkoxide andcarboxylate compounds. Furthermore we have also shown theability of ester elimination derived molecular clusters withspecific microstructure to be used in the synthesis of bulkmaterials retaining the structural attributes of the precursor cluster.     

还原性的类立方烷型金属有机原子簇[M_4(μ~3-Se)_4(η-C_5H_4R)_4](M=Mo,R=Pr~i;M=Cr,R=Me)的合成、晶体结构和电子性质

类立方烷型金属原子簇化合物M_4E_4(M为过渡金属,E为硫属元素)的研究长期以来受到重视,其主要原因有二:(1)一些类立方烷型金属原子簇(如Fe_4S_4及Fe-Mo-S原子簇)在生物体系(如固氮酶、铁氧还蛋白)中有重要意义;(2)由于可以方便地对M或E作系列性的改变,因而M_4E_4成为研究原子簇化合物的电子结构及检测各种有关的理论假设的重要模型化合物。