Showing papers by "Lei Zhang published in 2005"
TL;DR: In this paper, the authors investigated the dielectric properties and dc resistivity of oxygen-doped ceramic samples as a function of temperature and showed that phase separation disappears when the sample was annealed at different temperatures in reduced atmosphere to tune the oxygen content.
Abstract: The low-frequency $({10}^{2}--{10}^{5}\phantom{\rule{0.3em}{0ex}}\mathrm{Hz})$ dielectric properties and dc resistivity of oxygen-doped ${\mathrm{La}}_{2}\mathrm{Cu}{\mathrm{O}}_{4+y}$ ceramic samples were investigated as a function of temperature $(23--300\phantom{\rule{0.3em}{0ex}}\mathrm{K})$. The as-prepared sample featuring phase separation shows very high dielectric constant ${\ensuremath{\epsilon}}^{\ensuremath{'}}g{10}^{5}$ above $150\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, which was found to originate from the hopping motion of localized holes. Below $150\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, the relaxation process due to the condensation of the holes can be observed in the dielectric spectra. When the sample was annealed at different temperatures in reduced atmosphere to tune the oxygen content, the phase separation disappears accompanied by the absence of the relaxation in the annealed sample. Our results give strong support to the phase separation model and evidence the inhomogeneous distribution of holes in the oxygen-doped ${\mathrm{La}}_{2}\mathrm{Cu}{\mathrm{O}}_{4+y}$ ceramic samples investigated.
43 citations
TL;DR: Surprisingly, higher initial virus-specific CD8+ T-cell numbers lead to a longer delay prior to initial CD8-T-cell expansion, and slowerCD8- T- cell increases, which were associated with reduced peak and chronic viral loads and reduced CD4-cell depletion.
Abstract: CD8+ T lymphocytes are thought to play an important role in the control of acute and chronic human immunodeficiency virus infections. However, there is a significant delay between infection and the first observed increase in virus-specific CD8+ T-cell numbers. Prior to this time, viral kinetics are not significantly different between controls and vaccinees. Surprisingly, higher initial virus-specific CD8+ T-cell numbers lead to a longer delay prior to initial CD8+ T-cell expansion, and slower CD8+ T-cell increases. Nevertheless, higher initial CD8+ T-cell numbers were associated with reduced peak and chronic viral loads and reduced CD4+ T-cell depletion.
28 citations
Patent•
21 Jan 2005
TL;DR: In this article, a complicated tubular netted tissue engineering rack forming technology based on core dissolving technique belongs to the field of tissue-engineering rack manufacturing technology, which includes first designing 3D model of rack and rack core, making rack core with water soluble material without biotoxicity through fast laminated formation; compounding solution of biocompatible material with proper amount of pore creating agent and coating the solution onto the rack core; air drying, soaking in distilled water to dissolve out rack core and pore-creating agent, taking out and volatilizing
Abstract: The method of complicated tubular netted tissue engineering rack forming technology based on core dissolving technique belongs to the field of tissue engineering rack manufacturing technology The technological process includes first designing 3D model of rack and rack core; making rack core with water soluble material without biotoxicity through fast laminated formation; compounding solution of biocompatible material with proper amount of pore creating agent and coating the solution onto the rack core; air drying, soaking in distilled water to dissolve out rack core and pore creating agent, taking out and volatilizing water and coating different forming material with or without pore creating agent successively to form the tubular netted rack with complicated spatial structure, different material gradient and different pore gradient
23 citations
28 Feb 2005
TL;DR: In this paper, the disturbance decoupling problem of switched nonlinear systems with arbitrary switching law is investigated by first considering the invariant and weak-invariant distributions of switched NN systems.
Abstract: The disturbance decoupling problem of switched nonlinear systems with arbitrary switching law is investigated by first considering the invariant and weak-invariant distributions of switched nonlinear systems. Based on the invariant distribution, the disturbance decoupling problem under two kinds of switching information is considered, using switch-dependent and switch-independent feedback. Sufficient conditions are obtained for solving the problem. An algorithm for the largest invariant distribution contained in the kernel of outputs is presented.
20 citations
13 Mar 2005
TL;DR: The objective is to find a schedule to guarantee the safety of all vehicles and a tabu search (TS) heuristic with a dynamic penalty mechanism to obtain good solutions is proposed.
Abstract: In this work, we study the problem of the safe transportation of hazardous materials, which is an important operational problem and has been studied extensively in the literature. We outline previous work and propose a new model that is a variant of the vehicle routing problem with time windows (VRPTW). The objective is to find a schedule to guarantee the safety of all vehicles. We propose a tabu search (TS) heuristic with a dynamic penalty mechanism to obtain good solutions. A realistic data generation mechanism is also presented and the elaborate computational results show the strengths of our algorithms.
12 citations