Abnormal dielectric characteristics of PMN-32%PT single crystal under dc bias

It has been reported that the single crystal of relaxor ferroelectrics (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) with the compositions near the morphotropic phase boundary (MPB, 0.28相似文献   

Preparation and optical properties of solid solution semiconductor (Zn x Cd1−x S) doped silica glasses

Semiconductor(Zn_xCd_1−x S) doped silica glasses were prepared by Sol-Gel process andin situ growth technique. The structure of the materials was characterized by X-ray diffraction technique, the particle size of semiconductor crystallites from X-ray patterns was estimated less than 10 nm. From absorption spectra, it is obtained that the absorption edges shifted to short wavelength direction when Zn contents increased, and the absorption edge can be adjusted from 2.46 eV to 2.96 eV by controlling Zn contents. The third-order nonlinear optical susceptibility was studied at 532 nm with 8 ns pulse laser by degenerate four wave mixing (DFWM) technique.     

Nonnegative matrix factorization and its applications in pattern recognition

Matrix factorization has been widely used in many fields[1]. In numerical algebra, the large-scale and com- plex problems can be transformed into small-scale sim- ple subproblems by matrix factorization; in applied statistics, low rank approximation of or…     

The glass transition temperature and microstructure of polyurethane/epoxy resin interpenetrating polymer networks nanocomposites

GLASS TRANSITION TEMPERATURE (TG) HAS BEEN EXTEN- SIVELY STUDIED FOR MANY POLYMERS SINCE IT IS ONE OF THE MOST FUNDAMENTAL FEATURES RELATIVE DIRECTLY TO POLYMER PROPERTIES. IN GENERAL, INORGANIC NANOFILLERS DO NOT DI- RECTLY CONTRIBUTE TO THE TG OF THE MA…     

Surface modification of poly（vinyl chloride） by long-distance and direct argon RF plasma

AS AN ELECTRICALLY NEUTRAL, HIGHLY IONIZED GAS COM- POSED OF IONS, ELECTRONS, AND NEUTRAL PARTICLES, PLASMA IS A PHASE OF MATTER DISTINCT FROM SOLIDS, LIQUIDS, AND NOR- MAL GASES,KNOWN AS THE FOURTH STATE OF MATTER[1]. RECENT YEARS SEE GREAT PROGRESS IN P…     

Characterization of polyphenol oxidase from plants

Polyphenol oxidase (PPO) which can mediate browning reaction is a bifunctional copper-containing enzyme encoded by plant nucleolus gene. It usually leads to excessive browning reaction which reduces the coercial profits of fruits and vegetables. In this paper, PPO genes and enzymes in plants are characterized systematically, and the latest progress is reviewed. Some clonings of PPOs genes are reported; the specific temporal and spatial expression pattern of PPOs genes is described; the model of the structure of the precursor form of catechol oxidase is introduced; the possible functions of PPOs in defending against pathogen, wounding, surrounding stress and other inducing factors are demonstrated; the induction and activation of latent PPOs in some plants is elucidated; the scheme of browning inhibition by L-cysteine is clarified; the mechanism of suicide inhibition of latent PPO and kinetic synergism are established. Furthermore, the area for future study is also discussed.     

Reliable fuzzy control with domain guaranteed cost for fuzzy systems with actuator failures

The reliable fuzzy control with guaranteed cost for T-S fuzzy systems with actuator failure is proposed in this paper. The cost function is a quadratic function with failure input. When the initial state of such systems is known, a design method of the reliable fuzzy controller with reliable guaranteed cost is presented, and the formula of the guaranteed cost is established. When the initial state of such systems is unknown but belongs to a known bounded closed domain, a notion of the reliable domain guaranteed cost (RDGC) for such systems is proposed. For two classes of initial state domain, polygon domain and ellipsoid domain, some design methods for reliable fuzzy controllers with the RDGC are provided. The efficiency of our design methods is finally verified by numerical design and simulation on the Rossler chaotic system.     

高维小波框架包子空间对空间L2(Rn)的分解

研究小波框架包子空间对空间L²(Rⁿ)的分解。运用时频分析方法与逼近论思想,刻画了数量矩阵伸缩的高维小波框架包的特征,构造了若干高维小波框架包子空间,进而,由小波框架包子空间得到了L²(Rⁿ)的直交分解式。给出高维小波框架包函数的频域表达式,类似于正交基,提出高维紧小波框架包构成空间L²(Rⁿ)的巴塞尔框架的充分条件,扩展了小波框架应用范围。     

基于期权采购的政企联合储备应急物资模型

政企联合储备应急物资能够有效地改善政府单独储备物资所面临的储备过量或不足的困境,而通过市场化的契约机制实现政企联合储备可以克服行政强制手段带来的弊端.基于此,本文建立了基于期权采购的政企联合储备应急物资模型,通过推导获得政企双方的最优决策后,给出了企业参与联合储备的条件,以及在不同的现货市场条件下,与政府单独储备模式相比,政企联合储备模式能够提高物资总储备量且降低政府库存水平时契约参数的取值范围.在此基础上,本文给出了供应链达到协调以及政企双方实现合作共赢时的条件.最后,本文通过数值模拟对上述结论进行了验证,并进一步研究物资需求量不确定性对两种储备模式的影响,结果表明随着需求量不确定性的增加,与政府单独储备模式相比,政企联合储备模式的优势越发明显.