一类特殊线性双层规划的对偶规划

本文首先给出值型线性双层规划的等价形式 ,然后讨论了非增的值型线性双层规划的 Johri一般对偶规划 ,并且说明了其对偶间隙等于零 ,最后说明了它们最优解的关系     

Beam splitting, combining, and cross coupling through multiple superimposed volume-index gratings

We investigate the diffraction properties of multiple-superimposed index gratings from a vector synthetic viewpoint using coupled wave analysis with Bragg and non-Bragg readout. The vector synthetic gratings consist of two volume-index gratings with different grating wave vectors, which can be obtained in photorefractive materials, in optical fibers or in Bragg cells with two driving acoustic waves. This structure can realize beam splitting, beam combining, and beam cross coupling, etc. Analytic expressions for the diffraction efficiency as well as the amplitude of the waves involved are obtained. The results are presented and discussed.     

微流控芯片实验室

以作者所在课题组近年来的研究工作为基础,就芯片实验室平台建设及相应的以系统生物学为最终目标的功能化研究作一说明,对在分子和细胞层面,甚至是单分子、单细胞水平上实现以规模集成为特征的临床诊断和药物筛选的努力予以特别的关注。     

固相萃取-高效液相色谱法测定辣椒中甲基硫菌灵的残留量

甲基硫菌灵的化学名称为1,2-双(3-甲氧羰基-2-硫脲基)-苯,是内吸性杀菌剂,对蔬菜、水果、麦类等的真菌病害有良好的防治效果。它在生物体内和环境中不稳定,因而增加了测定的难度。已报道的分析方法有生物测定法、紫外分光光度法、气相色谱法和液相色谱法。这些方法的样品前处理繁琐,有机溶剂用量多,分析时间长。本文采用中性氧化铝固相萃取小柱净化样品,     

Wishartness and independence of matrix quadratic forms in a normal random matrix

Let Y be an n×p multivariate normal random matrix with general covariance Σ_Y. The general covariance Σ_Y of Y means that the collection of all np elements in Y has an arbitrary np×np covariance matrix. A set of general, succinct and verifiable necessary and sufficient conditions is established for matrix quadratic forms Y^′W_iY's with the symmetric W_i's to be an independent family of random matrices distributed as Wishart distributions. Moreover, a set of general necessary and sufficient conditions is obtained for matrix quadratic forms Y^′W_iY's to be an independent family of random matrices distributed as noncentral Wishart distributions. Some usual versions of Cochran's theorem are presented as the special cases of these results.     

Impulsive boundary value problems with nonlinear boundary conditions

In this paper, the upper and lower solution method and Schauder’s fixed point theorem are employed in the study of boundary value problems for a class of second-order impulsive ordinary differential equations with nonlinear boundary conditions. We prove the existence of solutions to the problem under the assumption that there exist lower and upper solutions associated with the problem.     

Synthesis of well‐defined pH‐responsive PPEGMEA‐g‐P2VP double hydrophilic graft copolymer via sequential SET‐LRP and ATRP

A series of well‐defined double hydrophilic graft copolymers containing poly(poly(ethylene glycol) methyl ether acrylate) (PPEGMEA) backbone and poly(2‐vinylpyridine) (P2VP) side chains were synthesized by successive single electron transfer living radical polymerization (SET‐LRP) and atom transfer radical polymerization (ATRP). The backbone was first prepared by SET‐LRP of poly(ethylene glycol) methyl ether acrylate (PEGMEA) macromonomer using CuBr/tris(2‐(dimethylamino)ethyl)amine as catalytic system. The obtained homopolymer then reacted with lithium diisopropylamide and 2‐chloropropionyl chloride at ?78 °C to afford PPEGMEA‐Cl macroinitiator. poly(poly(ethylene glycol) methyl ether acrylate)‐g‐poly(2‐vinylpyridine) double hydrophilic graft copolymers were finally synthesized by. ATRP of 2‐vinylpyridine initiated by PPEGMEA‐Cl macroinitiator at 25 °C using CuCl/hexamethyldiethylenetriamine as catalytic system via the grafting‐ from strategy. The molecular weights of both the backbone and the side chains were controllable and the molecular weight distributions kept relatively narrow (M_w/M_n ≤ 1.40). pH‐Responsive micellization behavior was investigated by ¹H NMR, dynamic light scattering, and transmission electron microscopy and this kind of double hydrophilic graft copolymer aggregated to form micelles with P2VP‐core while pH of the aqueous solution was above 5.0. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A new phenothiazine-based fluorescence sensor for imaging Hg2+ in living cells

A new phenothiazine-based sensor PHE-Ad for monitoring Hg²⁺ has been designed and synthesized based on the intramolecular charge transfer (ICT) mechanism. The probes were characterized by FTIR, ¹H NMR, and HRMS, and their optical properties were detected by UV and FL. It's showed the probes detection of Hg²⁺ compared to other metal ions (Mg²⁺, Cu²⁺, Hg²⁺, Ag⁺, Co²⁺, Cr³⁺, Al³⁺, Ni²⁺, Zn²⁺, Ca²⁺, Fe³⁺, Fe²⁺, K⁺, Na⁺, and Cd²⁺) based on the test results. Besides, the detection limits were determined to be 2.12 × 10⁻⁸ M through the standard curve plot. In addition, sensor PHE-Ad shows high selectivity and sensitivity for Hg²⁺ with a fast response in a suitable pH range. Furthermore, taking into account its good “turn-on” fluorescent sensing behavior and low cell cytotoxicity, PHE-Ad was successfully applied to detect and image Hg²⁺ in real water samples and living cells, which shows great potentials for application in environmental and biological systems.     

Integrating Data Transformation in Principal Components Analysis

Principal component analysis (PCA) is a popular dimension-reduction method to reduce the complexity and obtain the informative aspects of high-dimensional datasets. When the data distribution is skewed, data transformation is commonly used prior to applying PCA. Such transformation is usually obtained from previous studies, prior knowledge, or trial-and-error. In this work, we develop a model-based method that integrates data transformation in PCA and finds an appropriate data transformation using the maximum profile likelihood. Extensions of the method to handle functional data and missing values are also developed. Several numerical algorithms are provided for efficient computation. The proposed method is illustrated using simulated and real-world data examples. Supplementary materials for this article are available online.