Minimum permanents of doubly stochastic matrices with at least one zero entry †

It is shown that the minimum value of the permanent on the n× ndoubly stochastic matrices which contain at least one zero entry is achieved at those matrices nearest to J_n in Euclidean norm, where J_n is the n× nmatrix each of whose entries is n^-1 . In case n ≠ 3 the minimum permanent is achieved only at those matrices nearest J_n ; for n= 3 it is achieved at other matrices containing one or more zero entries as well.     

Jordan isomorphisms of generalized structural matrix rings

We describe the sub-bimodules of matrix bimodules over two structural matrix rings. Structural matrix bimodules arise as particular such sub-bimodules, and we discuss when such a bimodule is faithful or indecomposable. As an application, we obtain a large class of rings whose Jordan isomorphisms are either ring isomorphisms or ring anti-isomorphisms. Complete upper block triangular matrix rings over 2-torsion-free indecomposable rings are elements of this class.     

Modeling based on subspace orthogonal projections for QSAR and QSPR research

A novel projection modeling method for quantitative structure activity relationship (QSAR) and quantitative structure property relationship (QSPR) is developed in this paper. Orthogonalization of block variables is introduced to deal with the problem of variable selection. Projections based on least squares are used to construct the modeling space in order to search for the best regression directions for chemical modeling. A suitable prediction space for such a model is further defined to confine the usage range of the model. Three real data sets were analyzed to check the performance of the proposed modeling method. The results obtained from Monte‐Carlo cross‐validation (MCCV) showed that the proposed modeling method might provide better results for QSAR and QSPR modeling than PCR and PLS with respect to both fitting and prediction abilities. Copyright © 2007 John Wiley & Sons, Ltd.     

含芳香基团的梳状聚合物型降凝剂与沥青质协同改善合成蜡油的流变性

采用流变学实验、 差示扫描量热(DSC)分析、 显微观察及沥青质沉淀实验研究了聚丙烯酸十八酯-马来酸酐(POM)、 聚丙烯酸十八酯-马来酸酐-苯胺(POMA)及聚丙烯酸十八酯-马来酸酐-萘胺(POMN)梳状聚合物对合成蜡油的流变性能的影响规律. 实验结果表明, 这3种梳状聚合物降凝剂均能在一定程度上改善不含沥青质合成蜡油(MO-1)的低温流变性, 其中POM对MO-1蜡油的流变性改善效果最佳. 添加500 mg/kg POM后, MO-1的凝点从29 ℃降至23 ℃, 屈服值从627.20 Pa降至83.35 Pa. 而POM, POMA和POMN可以显著改善含0.3%(质量分数)沥青质的合成蜡油(MO-2)的低温流变性, 且添加500 mg/kg POMA后MO-2蜡油的流变改善效果最佳: 凝点降至3 ℃, 屈服值降至1.27 Pa. 可见, 本文制备的梳状聚合物降凝剂均能与沥青质协同改善MO-2蜡油的流变性, 并且向POM中引入芳香基团能进一步促进沥青质与降凝剂分子的相互作用, 进而增强梳状聚合物降凝剂与沥青质的协同作用.     

Synthesis and characterization of novel functional poly(vinyl alcohol-co-styrene sulfonic acid) copolymers

This paper first time reports the preparation of random anionic copolymers from vinyl acetate (VAc) bearing electro-donating substituent and sodium 4-vinylbenzenesulfonate (SSA) having electro-withdrawing substituent. Copolymers (PVA-co-SSA) of different composition have been successfully prepared by a simple free radical solution polymerization technique. Resulting final copolymer contained neutral hydrophilic as well as ionizable ion exchange sites. Evaluation of spectral data obtained from Fourier transform Infrared spectroscopy, Raman spectroscopy, and ¹H Nuclear magnetic resonance helped in identifying and confirming the chemical structure of copolymers. Characterization of copolymers by gel permeation chromatography revealed high molecular weight with moderate polydispersity index. Analysis of thermal stability and glass transition temperature of copolymers by thermogravimetric analysis and differential scanning calorimetry were found in between corresponding homopolymers. Physicochemical properties of PVA-co-SSA can be beneficial for prospective advanced application in the niche area of smart membrane technology for energy and environment.     

Deterministic Secure Quantum Communication with Cluster State and Bell-Basis Measurements

We present a novel protocol for deterministic secure quantum communication by using the lour-qubit cluster state as quantum channel. It is shown that two legitimate users can directly transmit the secret messages based on Bellbasis measurements and classical communication. The present protocol makes use of the ideas of block transmission and decoy particle checking technique. It has a high capacity as each cluster state can carry two 5its of information, and has a high intrinsic efficieney 5ecause almost all the instances except the decoy checking particles （its numSer is negligible） are useful. Furthermore, this protocol is feasible with present-day technique.     

偶氮苯聚合物全息光栅衍射效率和偏振特性研究

研究了不同偏振全息模式下基于交联偶氮苯聚合物薄膜的相位光栅的形成机理、衍射效率和偏振特性.利用琼斯矢量表征了正交线偏振(SP)和半行线偏振(SS)干涉模式下的偏振干涉场.基于SP和SS两种模式,制作了无明显表成起伏的纯折射率光栅和有表面起伏的浮雕光栅.偏光显微镜(POM)观测说明纯折射率光栅具有周期性的折射率分布;近场光学显微镜(SNOM)探测说明纯折射率光栅和浮雕光栅的表而起伏在5 nm以下和 85.23 nm.实验表明.当探测光为水平偏振时,纯折射率光栅的衍射效率达到22.2%.浮雕光栅只能达到1.65%.纯折射率光栅的0、 1级衍射光分别为水平和竖直线偏振光,偏振度达到0.9969和0.9963;浮雕光栅的0, 1级衍射光均为水平线偏振光.