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101.
In this paper, the existence of periodic traveling wave solutions with a priori unknown velocity is considered for a coupled map lattice dynamical system. By trasforming our problem into one that involves polynomials, explicit 2- and 3-periodic traveling wave solutions are found, while the other solutions can be computed numerically. Since there does not seem to be any reports on explicit traveling wave solutions, we hope that our results will lead to the discovery of many others. 相似文献
102.
Based on the Independent Continuous Mapping method (ICM), a topological optimization model with continuous topological variables is built by introducing three filter functions for element weight, element allowable stress and element stiffness, which transform the 0-1 type discrete topological variables into continuous topological variables between 0 and 1. Two methods for the filter functions are adopted to avoid the structural singularity and recover falsely deleted elements: the weak material element method and the tiny section element method. Three criteria (no structural singularity, no violated constraints and no change of structural weight) are introduced to judge iteration convergence. These criteria allow finding an appropriate threshold by adjusting a discount factor in the iteration procedure. To improve the efficiency, the original optimization model is transformed into a dual problem according to the dual theory and solved in its dual space. By using MSC/Nastran as the structural solver and MSC/Patran as the developing platform, a topological optimization software of frame structures is accomplished. Numerical examples show that the ICM method is very efficient for the topological optimization of frame structures.The project supported by the National Natural Science Foundation of China (10472003) and Beijing Natural Science Foundation (3042002) The English text was polished by Yunming Chen. 相似文献
103.
<正>Tetracycline selective electrode using molecularly imprinted polymer particles as quasi-ionophore was constructed the first time, and its performance was carefully characterized.Due to the specific recognition of tetracycline by the particles,the selectivity coefficients for routine interferences were less than 10~(-4).Benefited from the absence of tetracycline in the sensitive membrane and the optimized composition of the inner filling solution,the limit of detection of the electrode was reduced to about 2.5×10~(-8) mol/ L.It exhibited a good electrode slope 57.6 mV/decade near the theoretical Nernstian one,with a wide linear working range from 6.0×10~(-8) to 1.0×10~(-3) mol/L.The fabricated electrode should be used in pH 2-4,response time of which was less than 200 s when the concentration of tetracycline was higher than 1.0×10~(-6) mol/L and no more than 30 min at the concentration of 1.0×10~(-8) mol/L. 相似文献
104.
Ruohong Sui Suya Liu Gilles A. Lajoie Paul A. Charpentier 《Journal of separation science》2010,33(11):1604-1609
The search for a method to fabricate monolithic inorganic columns has attracted significant recent attention due to their unique ability in separation applications of various biomolecules. Silica and polymer based monolithic columns have been prepared, but titania and other metal oxide monoliths have been elusive, primarily due to their fragility. This article describes a new approach for preparing nanostructured titania based columns, which offer better performance over conventional particle packed columns for separating a wide variety of biomolecules including phosphopeptides. TiO2 monolithic aerogels were synthesized in separation columns using in situ sol‐gel reactions in supercritical carbon dioxide (scCO2) followed by calcination, and compared to those prepared in heptanes. The characterization results show that scCO2 is a better solvent for the sol‐gel reactions, providing lower shrinkage with the anatase TiO2 monolith composed of nanofibers with very high surface areas. The monolithic columns show the ability to isolate phosphopeptides with little flow resistance compared to conventional titania particle based microcolumns. 相似文献
105.
106.
In this paper, we present a new self-adaptive alternating direction method for solving a class of variational inequality problems with both linear equality and inequality constraints without the need to add any extra slack variables. The method is simple because it needs only to perform some projections and function evaluations. In addition, to further enhance its efficiency, we adopt a self-adaptive strategy to adjust parameter μ at each iteration. Convergence of the proposed method is proved under certain conditions. Numerical experience illustrates the efficiency of the new method. 相似文献
107.
Huirui Zhou Ke Tao Yunqi Sui Kang Sun 《Physica E: Low-dimensional Systems and Nanostructures》2011,44(3):597-604
The heterogeneous nucleation and growth of CdSe domains on the Fe3O4 seed nanocrystals are hard to be controlled because of significant lattice mismatch between Fe3O4 and CdSe nanocrystals. Current study exploits the choice of surface ligand and crystal morphology for Fe3O4 seed to investigate ways to overcome the energy barrier imposed by the lattice mismatch for the promotion and control of subsequent growth of CdSe nanocrystals on seeded crystals. Results indicate that the growth of CdSe domains on seed nanocrystals not only depends on the affinity of ligands toward seed nanocrystals, but also is affected by the seed ligands in a similar way to synthesizing individual second-domain nanocrystals. Furthermore, preferential growth of CdSe domains on the corner of cubic seeds are observed, and cubic Fe3O4 nanocrystals are favored for the heterogeneous nucleation of CdSe as opposed to spherical ones. A three-stage growth model (heterostructures formation, the adsorption of Se and the heterogeneous nucleation and growth) is proposed, where choice of ligands, geometry features, such as surface curvature and defects are found to have significant impact to overcome energy barrier from lattice mismatch. 相似文献
108.
Hao Cheng Xiujian Zhao Xiaotao Sui Yuli Xiong Jiang Zhao 《Journal of nanoparticle research》2011,13(2):555-562
CdS quantum dot (Qd)-sensitized TiO2 nanotube array photoelectrode is synthesised via a two-step method on tin-doped In2O3-coated (ITO) glass substrate. TiO2 nanotube arrays are prepared in the ethylene glycol electrolyte solution by anodizing titanium films which are deposited
on ITO glass substrate by radio frequency sputtering. Then, the CdS Qds are deposited on the nanotubes by successive ionic
layer adsorption and reaction technique. The resulting nanotube arrays are characterized by scanning electron microscopy,
X-ray diffraction (XRD) and UV–visible absorption spectroscopy. The length of the obtained nanotubes reaches 1.60 μm and their
inner diameter and wall thickness are around 90 and 20 nm, respectively. The XRD results show that the as-prepared TiO2 nanotubes array is amorphous, which are converted to anatase TiO2 after annealed at 450 °C for 2 h. The CdS Qds deposited on the TiO2 nanotubes shift the absorption edge of TiO2 from 388 to 494 nm. The results show that the CdS-sensitized TiO2 nanotubes array film can be used as the photoelectrode for solar cells. 相似文献
109.
为了实现对黄瓜病害的快速无损准确预测,基于激光诱导叶绿素荧光光谱分析技术,建立了温室黄瓜霜霉病害的预测模型.通过测定健康叶片、病菌接种3d叶片和接种6d叶片的光谱曲线,采用一阶导数光谱预处理方法,结合主成分分析数据降维方法对三组光谱数据进行特征信息提取后,建立主成分得分散点图,依据累积贡献率选取10个主成分代替导数光谱... 相似文献
110.