Selective Hydroxy Group Protection of Gallic Acid

An efficient procedure allowing selective differentiation of the 4-hydroxy group of methyl gallate was reported.     

Thermal Behaviour of Complexes of Antipyrine Derivatives

Parent and mixed ligand complexes of cobalt and copper with antipyrine derivatives of 1,2-ethanediamine or piperazine and with 2-aminobenzothiazole (TAB) were synthesized and their thermal behaviour was investigated. The complexes contain N,N′-bis(4-antipyrylmethyl)-piperazine (BAMP) or N,N′-tetra(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN) or/and TAB as ligand, and Cl⁻, ClO₄ ⁻ or SCN⁻. The complexes decompose with the evolution of heat. The decomposition route depends on the presence of ClO₄ ⁻. If the ClO₄ ⁻ is not coordinated, it oxidizes the TAB and BAMP or TAMEN and the decomposition is explosive. This revised version was published online in August 2006 with corrections to the Cover Date.     

单个N维量子系统的量子秘密共享

提出了一种单个N维量子系统的量子秘密共享方案.在该方案中，利用对Bennett和Brassard协议(BB84协议)中使用的两基四态扩展到多基多态，分发者对要共享的秘密采用多基多态编码，将被编码的单个N维量子系统发送给他的两个代理人之一，该代理人利用一个N维克隆机对接收到的粒子做幺正操作，然后把粒子发送给另一代理人.在得知最后一个代理人接收到该粒子之后，分发者告知两个代理人他所用的制备基，然后两个代理人分别对自己的系统进行测量并在合作之后获知分发者所发送的粒子的量子态.该方案的安全性基于量子不可克隆定理. 关键词： 量子秘密共享 多基多态编码 N维克隆机 量子不可克隆定理     

G-frames and g-Riesz bases

G-frames are generalized frames which include ordinary frames, bounded invertible linear operators, as well as many recent generalizations of frames, e.g., bounded quasi-projectors and frames of subspaces. G-frames are natural generalizations of frames and provide more choices on analyzing functions from frame expansion coefficients. We give characterizations of g-frames and prove that g-frames share many useful properties with frames. We also give a generalized version of Riesz bases and orthonormal bases. As an application, we get atomic resolutions for bounded linear operators.     

零维代数簇的分解及其应用

本文利用Groebner基，给出了一种分解零维代数簇的方法，并且讨论了这种方法在理想的准素分解以及几何定理机器证明中的应用．     

Moduli Spaces of Curves with Quasi-Symmetric Weierstrass GAp Seqnences

In this paper we give an explicit construction of the moduli space of the pointed complete Gorenstein curves of arithmetic genus g with a given quasi-symmetric Weierstrass semigroup, that is, a Weierstrass semigroup whose last gap is equal to 2g – 2. We identify such a curve with its image under the canonical embedding in the (g – 1)-dimensional projective space. By normalizing the coefficients of the quadratic relations and by constructing Gröbner bases of the canonical ideal, we obtain the equations of the moduli space in terms of Buchberger's criterion. Moreover, by analyzing syzygies of the canonical ideal we establish criteria that make the computations less expensive.     

Kinetics of ethylenediamine and piperazine ethoxylation

The ethoxylation of ethylenediamine and piperazine was studied in the temperature range 343 - 363 K in the presence of 0 - 10 % water. Kinetic parameters of all reactions occurring in the system and a factor describing the water effect on the rate of the reactions are given. No formation of quaternary bases was observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

具1-关系的正规乘基的有限表示型

本文确定了所有的具有１－关系的正规乘基的有限表示型连通基本代数。     

Supramolecular Stabilization of Metastable Tautomers in Solution and the Solid State

This work presents a successful application of a recently reported supramolecular strategy for stabilization of metastable tautomers in cocrystals to monocomponent, non‐heterocyclic, tautomeric solids. Quantum‐chemical computations and solution studies show that the investigated Schiff base molecule, derived from 3‐methoxysalicylaldehyde and 2‐amino‐3‐hydroxypyridine ( ap ), is far more stable as the enol tautomer. In the solid state, however, in all three obtained polymorphic forms it exists solely as the keto tautomer, in each case stabilized by an unexpected hydrogen‐bonding pattern. Computations have shown that hydrogen bonding of the investigated Schiff base with suitable molecules shifts the tautomeric equilibrium to the less stable keto form. The extremes to which supramolecular stabilization can lead are demonstrated by the two polymorphs of molecular complexes of the Schiff base with ap . The molecules of both constituents of molecular complexes are present as metastable tautomers (keto anion and protonated pyridine, respectively), which stabilize each other through a very strong hydrogen bond. All the obtained solid forms proved stable in various solid‐state and solvent‐mediated methods used to establish their relative thermodynamic stabilities and possible interconversion conditions.