摘要：
A kind of coenzyme A (CoA)-silver coordination complex (CoA-Ag) was in-situ developed and verified to accelerate the electron transferring and electrochemical catalysis of H2O2 decomposition to enhance the cathode ECL intensity of CdTe@CdS QDs. Afterward, a convenient label-free signal-on ECL approach was constructed for CoA detection with excellent specificity. In addition, the unique ECL enhancing phenomenon was also proposed to assay the enzymatic activity of histone acetyltransferases (HAT) and screen relevant inhibitors, exhibiting a promising potential in the practical application of biochemical research, disease diagnosis and drug discovery.
摘要：
In this paper, we consider the following semilinear elliptic systems:
$$\begin{aligned} \left\{ \begin{array}{ll} \displaystyle -\Delta u+V(x)u=F_{u}(x, u, v),\quad \text{ in } \mathbb {R}^{N},\\ -\Delta v+V(x)v=F_{v}(x, u, v),\quad \text{ in } \mathbb {R}^{N},\\ \end{array} \right. \end{aligned}$$
where
$$V:\mathbb {R}^{N}\rightarrow \mathbb {R},~F_{u}(x,u,v)$$
and
$$F_{v}(x,u,v)$$
are periodic in x. We assume that 0 is a right boundary point of the essential spectrum of
$$-\triangle +V$$
. Under appropriate assumptions on
$$F_{u}(x, u, v)$$
and
$$F_{v}(x, u, v)$$
, we prove the above system has a ground-state solution by using the Nehari-type technique in a strongly indefinite setting. Furthermore, the existence of infinitely many geometrically distinct solutions is obtained via variational methods. Recent results from the literature are improved and extended.
期刊：
Journal of Computational and Applied Mathematics,2018年329:57-67 ISSN：0377-0427
通讯作者：
Zhang, Jie
作者机构：
[Liu, Xiuping; Li, Yujiao; Cao, Junjie; Chen, He] Dalian Univ Technol, Sch Math Sci, Dalian, Peoples R China.;[Cao, Junjie] Nanchang Hangkong Univ, Coll Math & Informat Sci, Nanchang, Jiangxi, Peoples R China.;[Zhang, Jie] Liaoning Normal Univ, Sch Math, Dalian, Peoples R China.;[Zou, Changqing] Hengyang Normal Univ, Hengyang, Hunan, Peoples R China.
通讯机构：
[Zhang, Jie] L;Liaoning Normal Univ, Sch Math, Dalian, Peoples R China.
会议名称：
International Conference on Information and Computational Science (ICICS)
会议时间：
AUG 02-06, 2016
会议地点：
Dalian Univ Technol, Dalian, PAKISTAN
会议主办单位：
Dalian Univ Technol
关键词：
Normal estimation;Point cloud;Neighborhood shift
摘要：
For accurately estimating the normal of a point, the structure of its neighborhood has to be analyzed. All the previous methods use some neighborhood centering at the point, which is prone to be sampled from different surface patches when the point is near sharp features. Then more inaccurate normals or higher computation cost may be unavoidable. To conquer this problem, we present a fast and quality normal estimator based on neighborhood shift. Instead of using the neighborhood centered at the point, we wish to locate a neighborhood containing the point but clear of sharp features, which is usually not centering at the point. Two specific neighborhood shift techniques are designed in view of the complex structure of sharp features and the characteristic of raw point clouds. The experiments show that our method out-performs previous normal estimators in either quality or running time, even in the presence of noise and anisotropic sampling. (C) 2017 Elsevier B.V. All rights reserved.
摘要：
In this work, we propose a method for generating double-ring-shaped cylindrical vector beams by modulating Pancharatnam-Berry phase (PBP). The theoretical analysis shows that the output field can be expressed as the coherent superposition of two circularly polarized Laguerre-Gaussian components with opposite polarization handness and opposite helical index when a linearly polarized fundamental Gaussian beam inputs the metasurface designed based on PBP. Such a superposition of Laguerre-Gaussian modes forms a double ring-shaped cylindrical vector beam. Additionally, the local polarization orientation can be manipulated by changing the polarization angle of the input field. Our experimental results agree well with the theoretical expectation. We believe that PBP provides an extra choice to manipulate the phase and polarization of optical field. (C) 2017 Elsevier GmbH. All rights reserved.
摘要：
We propose a mesh saliency detection approach using absorbing Markov chain. Unlike most of the existing methods based on some center-surround operator, our method employs feature variance to obtain insignificant regions and considers both background and foreground cues. Firstly, we partition an input mesh into a set of segments using Ncuts algorithm and then each segment is over segmented into patches based on Zernike coefficients. Afterwards, some background patches are selected by computing feature variance within the segments. Secondly, the absorbed time of each node is calculated via absorbing Markov chain with the background patches as absorbing nodes, which gives a preliminary saliency measure. Thirdly, a refined saliency result is generated in a similar way but with foreground nodes extracted from the preliminary saliency map as absorbing nodes, which inhibits the background and efficiently enhances salient foreground regions. Finally, a Laplacian-based smoothing procedure is utilized to spread the patch saliency to each vertex. Experimental results demonstrate that our scheme performs competitively against the state-of-the-art approaches.
摘要：
The surface characteristics of carriers outstandingly influence the application of immobilized enzymes. Because of its biocompatible and multi-functional groups, chitosan was introduced into poly(styrene-co-glycidyl methacrylate) (PSt-GMA) microspheres with/without spacer-arms. Pepsin was immobilized onto these microspheres by a simple and mild process, and then its enzymatic activity was evaluated. As for the different modified microspheres, the interactions between the carrier and enzyme molecules would be different, influencing the immobilized system. The experimental results suggested that the optimal pH for immobilized enzyme was close to the optimal reaction pH of free enzyme. It was also found that the Freundlich model fit the immobilized process better than the Langmuir model. In addition, pepsin immobilized onto chitosan modified microspheres (CMM, M3-M4) possessed a higher affinity to substrate, hemoglobin. Compared to free pepsin, the optimal reaction temperature of immobilized pepsin onto modified microspheres (M2-M4) shifted toward higher temperature. Furthermore, the thermal and storage stabilities of pepsin after immobilization were enhanced, particularly for pepsin immobilizing onto CMMs. The pepsin linked onto M3/M4 still retained approximately 70% of enzymatic activity after storing 50 days, compared to below 20% for free pepsin. In a word, CMMs provide more interactions and biocompatible surface for immobilized enzymes.
期刊：
Journal of Applied Mathematics and Computing,2013年42(1-2):89-102 ISSN：1598-5865
通讯作者：
Yang, L.(yangliu19731974@yahoo.com.cn)
作者机构：
[Liu Yang; Liping Luo; Zhenguo Luo] Department of Mathematics and Computing Sciences, Hengyang Normal University, Hengyang, People’s Republic of China;[Haibo Chen] Department of Mathematics, Central South University, Changsha, People’s Republic of China
通讯机构：
[Liu Yang] D;Department of Mathematics and Computing Sciences, Hengyang Normal University, Hengyang, People’s Republic of China
摘要：
In this paper, we investigate the positive solutions for a class of nonlinear q-fractional boundary value problem. We not only obtain the existence and uniqueness of positive solutions, but also establish the iterative schemes for approximating the solutions, which is benefit for computation and application.
摘要：
In this paper, we investigate the existence of infinitely many homoclinic solutions for a class of second order Hamiltonian systems. By using fountain theorem due to Zou, we obtain two new criteria for guaranteeing that second order Hamiltonian systems have infinitely many homoclinic solutions. Recent results in the literature are generalized and significantly improved.
作者机构：
[Chen, Haibo; Yang, Liu; Yang, Xiaoxia] Cent S Univ, Dept Math, Changsha 410075, Hunan, Peoples R China.;[Yang, Liu] Hengyang Normal Univ, Dept Math & Computat Sci, Hengyang 421008, Hunan, Peoples R China.
通讯机构：
[Chen, Haibo] C;Cent S Univ, Dept Math, Changsha 410075, Hunan, Peoples R China.
关键词：
Fourth-order differential systems;Solution generated from a boundary condition;Critical point
摘要：
In this work, we investigate a boundary value problem for fourth-order differential systems. By using variational methods and a three-critical-point theorem, we establish sufficient conditions under which such a system possesses two solutions generated from a boundary condition. To illustrate the main results, an example is given.
摘要：
We study a nonlocal boundary value problem of impulsive fractional differential equations. By means of a fixed point theorem due to O'Regan, we establish sufficient conditions for the existence of at least one solution of the problem. For the illustration of the main result, an example is given.
期刊：
Abstract and Applied Analysis,2011年2011:1-15 ISSN：1085-3375
通讯作者：
Chen, Haibo
作者机构：
[Chen, Haibo; Yang, Liu] Cent S Univ, Dept Math, Changsha 421008, Hunan, Peoples R China.;[Yang, Liu] Hengyang Normal Univ, Dept Math & Comp Sci, Hengyang 421008, Hunan, Peoples R China.
通讯机构：
[Chen, Haibo] C;Cent S Univ, Dept Math, Changsha 421008, Hunan, Peoples R China.
关键词：
We investigate the existence and multiplicity of periodic solutions for a class of second-order differential systems with impulses. By using variational methods and critical point theory;we obtain such a system possesses at least one nonzero;two nonzero;or infinitely many periodic solutions generated by impulses under different conditions;respectively. Recent results in the literature are generalized and significantly improved. Published: 2011 First available in Project Euclid: 12 August 2011 zbMATH: 1253.34046 MathSciNet: MR2800077 Digital Object Identifier: 10.1155/2011/310957
摘要：
We investigate the existence and multiplicity of periodic solutions for a class of second-order differential systems with impulses. By using variational methods and critical point theory, we obtain such a system possesses at least one nonzero, two nonzero, or infinitely many periodic solutions generated by impulses under different conditions, respectively. Recent results in the literature are generalized and significantly improved.
期刊：
Journal of Applied Mathematics and Computing,2011年35(1-2):323-340 ISSN：1598-5865
通讯作者：
Sun, J.(sunjuntao2008@163.com)
作者机构：
[Liu Yang; Haibo Chen; Juntao Sun] Department of Mathematics, Central South University, Changsha, Hunan 410075, China;[Liu Yang] Department of Mathematics, Hengyang Normal University, Hengyang, Hunan 421008, China
通讯机构：
[Juntao Sun] D;Department of Mathematics, Central South University, Changsha, People’s Republic of China
关键词：
Abrupt change;Critical points;Critical-point theory;Dynamical behaviors;Evolution process;Fourth-order;Impulsive differential equation;Mathematical descriptions;Multiplicity of solutions;Nontrivial solution;Variational methods;Boundary value problems;Dynamical systems
摘要：
Many dynamical systems have impulsive dynamical behaviors due to abrupt changes at certain instants during the evolution process. The mathematical description of these phenomena leads to impulsive differential equations. In this paper, we study the existence and multiplicity of solutions for fourth-order impulsive differential equations. By using the variational methods and critical point theory, we give some new criteria to guarantee that the impulsive problem has at least one nontrivial solution, infinitely many distinct solutions under some different conditions, respectively. Some examples are given in this paper to illustrate the feasibilities of our main results.
摘要：
In this paper, we study the Schrodinger-Poisson system {-Delta u + V(x)u + lambda phi(x)u = K(x)f(u), in R(3), -Delta phi = u(2), u > 0, in R(3), (SP) and prove the existence of positive solutions for system (SP) when the nonlinearity f has growth at most linear for lambda small, allowing the potential V(x) to vanish at infinity. In addition, also we obtain the nonexistence of a nontrivial positive solution for lambda >= 1/4. (C) 2010 Elsevier Ltd. All rights reserved.
