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Search Results: 1 - 10 of 81474 matches for " Lixin Liu "
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The Progress of Photoluminescent Properties of Rare-Earth-Ions-Doped Phosphate One-Dimensional Nanocrystals
Lixin Yu,Hai Liu
Journal of Nanomaterials , 2010, DOI: 10.1155/2010/461309
Abstract: One-dimensional (1D) nanostructures, such as tubes, wires, rods, and belts, have aroused remarkable attentions over the past decade due to a great deal of potential applications, such as data storage, advanced catalyst, and photoelectronic devices . On the other hand, in comparison with zero-dimensional (0D) nanostructures, the space anisotropy of 1D structures provided a better model system to study the dependence of electronic transport, optical and mechanical properties on size confinement and dimensionality. Rare earth (RE) compounds, were intensively applied in luminescent and display devices. It is expected that in nanosized RE compounds the luminescent quantum efficiency (QE) and display resolution could be improved. In this paper, we systematically reported the research progress of luminescent properties of RE-doped 1D orthophosphate nanocrystal, including the synthesis of 1D nanostructures doped with RE ions, local symmetry of host, electronic transition processes, energy transfer (ET), and so forth. 1. Introduction It is well known that the reduction of particle size of crystalline system can result in remarkable modification of their properties which are different from those of microsized hosts because of surface effect and quantum confinement effect of nanometer materials. In 1994, Bhargava et al. reported that radiative transition rate of ZnS:Mn nanocrystals increased five orders in comparison with bulk one [1]. Although this result was strongly criticized later, the studies on nanosized luminescent semiconductor attracted great interests [2–6]. RE compounds were extensively applied in luminescence and display, such as lighting, field emission display (FED), cathode ray tubes (CRT), and plasma display panel (PDP) [7–11]. Lanthanide orthophosphate (LnPO4) belongs to two polymorphic types, the monoclinic monazite type (for La to Gd) and quadratic xenotime type (for Tb to Lu). Due to its high QE, bulk lanthanide phosphate as an ideal host in fluorescent lamps, CRT and PDP, has been extensively investigated [12–14]. It is expected that nanosized RE compounds can increase luminescent QE and display resolution. To improve luminescent properties of nanocrystalline phosphors, many preparation methods have been used, such as solid state reactions, sol-gel techniques, hydroxide precipitation, hydrothermal synthesis, spray pyrolysis, laser-heated evaporation, and combustion synthesis. Currently, the luminescent RE-doped 1D nanocrystals such as LaPO4:RE nanowires [15–19], Y2O3:RE and La2O3:Eu nanotubes/nanowires [20–25], and YVO4: Eu nanowires/nanorods
Leukocyte infiltration as a surrogate marker for diagnosis of invasion
Aijun Liu, Lixin Wei
International Journal of Biological Sciences , 2010,
Abstract: Dr. YG Man's hypothesis that breast tumor invasion is triggered by the aberrant leukocyte infiltration induced by degeneration of myoepithelial cells holds a lot of truth in our clinical practice, and leukocyte infiltration may be regarded as a surrogate marker for diagnosis of invasion.
Study of Genetic Algorithms on Optimizing PI Parameters in Prime Mover Simulation System
Lixin Tan,Juemin Liu
Computer and Information Science , 2009, DOI: 10.5539/cis.v1n4p172
Abstract: This paper proposes using the genetic algorithms to optimize the PI regulator parameter in the prime mover simulation system. In this paper, we compared the step response characteristics under the conditions of the genetic algorithms and traditional method by MATLAB simulation and field test tested the dynamic characteristics of the prime mover simulation system. The results proved that genetic algorithms can optimize PI parameters quickly .With this method the prime mover simulation system can meet the requirements of dynamic performance simulation.
Almost-isometry between Teichmüller metric and length-spectra metric on moduli space
Lixin Liu,Weixu Su
Mathematics , 2010,
Abstract: We prove an analogue of Farb-Masur's theorem that the length-spectra metric on moduli space is "almost isometric" to a simple model $\mathcal {V}(S)$ which is induced by the cone metric over the complex of curves. As an application, we know that the Teichm\"{u}ller metric and the length-spectra metric are "almost isometric" on moduli space, while they are not even quasi-isometric on Teichm\"{u}ller space.
The horofunction compactification of Teichmüller metric
Lixin Liu,Weixu Su
Mathematics , 2010,
Abstract: We show that the horofunction compactification of Teichm\"uller space with the Teichm\"uller metric is homeomorphic to the Gardiner-Masur compactification.
Variations of extremal length function on Teichmuller space
Lixin Liu,Weixu Su
Mathematics , 2012,
Abstract: By identifying extremal length function with energy of harmonic map from Riemann surface to R-tree, we compute the second variation of extremal length function along Weil-Petersson geodesic. We show that the extremal length of any simple closed curve is a pluri-subharmonic function on Teichmuller space.
Some metrics on Teichmüller spaces of surfaces of infinite type
Lixin Liu,Athanase Papadopoulos
Mathematics , 2008,
Abstract: Unlike the case of surfaces of topologically finite type, there are several different Teichm\"uller spaces that are associated to a surface of topological infinite type. These Teichm\"uller spaces first depend (set-theoretically) on whether we work in the hyperbolic category or in the conformal category. They also depend, given the choice of a point of view (hyperbolic or conformal), on the choice of a distance function on Teichm\"uller space. Examples of distance functions that appear naturally in the hyperbolic setting are the length spectrum distance and the bi-Lipschitz distance, and there are other useful distance functions. The Teichm\"uller spaces also depend on the choice of a basepoint. The aim of this paper is to present some examples, results and questions on the Teichm\"uller theory of surfaces of infinite topological type that do not appear in the setting the Teichm\"uller theory of surfaces of finite type. In particular, we point out relations and differences between the various Teichm\"uller spaces associated to a given surface of topological infinite type.
Research of an Efficient LED Lighting Driver Based on Boost-Buck Converter  [PDF]
Renbo Xu, Yongzhi Li, Lixin Zhong, Jiaming Liu
Circuits and Systems (CS) , 2014, DOI: 10.4236/cs.2014.56017

Boost-Buck converter is widely used in LED lighting drivers. In this paper, Boost-Buck main circuit related characteristics are firstly discussed, and then a new Boost-Buck high power efficient double loop control strategy is built by adopting error amplifier and integrator control method. It is demonstrated that the new system has many advantages such as high efficiency, fast response, strong anti-interference, good stability after analyses and simulations of its working dynamic characteristics.

Exact Solutions of the Generalized Benjamin-Bona-Mahony Equation
Xun Liu,Lixin Tian,Yuhai Wu
Mathematical Problems in Engineering , 2010, DOI: 10.1155/2010/796398
Abstract: We apply the theory of Weierstrass elliptic function to study exact solutions of the generalized Benjamin-Bona-Mahony equation. By using the theory of Weierstrass elliptic integration, we get some traveling wave solutions, which are expressed by the hyperbolic functions and trigonometric functions. This method is effective to find exact solutions of many other similar equations which have arbitrary-order nonlinearity. 1. Introduction The nonlinear phenomena in the scientific work or engineering fields are more and more attractive to scientists. To depict and analyze such nonlinear phenomena, the nonlinear evolutionary equations are playing an important role and their solitary wave solutions are the main interests of mathematicians and physicists. To obtain the traveling wave solutions of these nonlinear evolution equations, many methods were attempted, such as the inverse scattering method, Hirota’s bilinear transformation, the tanh-sech method, extended tanh method, sine-cosine method, homogeneous balance method, and exp-function method. With the aid of symbolic computation system, many explicit solutions are easily obtained, and many interesting works deeply promote the research of nonlinear phenomena. The present work is interested in generalized Benjamin-Bona-Mahony (BBM) equation: In the above equation, the first term of left side represents the evolution term while parameters and represent the coefficients of dual-power law nonlinearity, and are the coefficients of dispersion terms, is the power law parameter, and variable is the wave profile. In [1], Biswas used the solitary wave ansatz and obtained an exact 1-soliton solution of (1.1). In order to find more exact solutions of some nonlinear evolutionary equations, the Weierstrass elliptic function was introduced. For example, Kuru [2, 3] discussed the BBM-like equation, and Estévez et al. [4] analyzed another type of generalized BBM equations. In [5], Deng et al. also applied the similar method to the study of a nonlinear variant of the PHI-four equation. In this paper, we will apply the method to the generalized Benjamin-Bona-Mahony equation. The rest of this paper is organized as follows. In Section 2, we first outline the Weierstrass elliptic function method. In Section 3, we give exact expression of some traveling wave solutions of generalized Benjamin-Bona-Mahony (BBM) equation (1.1) by using the Weierstrass elliptic function method. Finally, some conclusions are given in Section 4. 2. Description of the Weierstrass Elliptic Function Method When we search for the solutions of some
Pharmacological Inhibition of p38 Mitogen-Activated Protein Kinases Affects KC/CXCL1-Induced Intraluminal Crawling, Transendothelial Migration, and Chemotaxis of Neutrophils In Vivo
Najia Xu,Mokarram Hossain,Lixin Liu
Mediators of Inflammation , 2013, DOI: 10.1155/2013/290565
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