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Search Results: 1 - 10 of 67924 matches for " Jun Zhou "
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The Impact of Political Instability on Madagascar Vanilla Exports  [PDF]
Anselme Andriamahery, Jun Zhou
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.64003
Abstract:
The main purpose of this paper is to investigate how the political instability in 2009 affected the Madagascar vanilla exports. Madagascar vanilla sector has experienced robust growth over the past decade which contributes to both the economy and the job creation, especially in northeast region where Vanilla was planted. However, this growth faced a serious problem after the political instability in 2009. This paper shows that the suspension of Africa Growth and Opportunity Act (AGOA), due to the political instability, had a large negative impact on vanilla exports. To estimate its impacts on vanilla exports, the international trade data permit us to isolate those impacts from various factors between Madagascar and other vanilla exporting countries by using the different-in-different (DID) technique. We take the sample of 2007 to 2011 by using Tobit model with random effects in addition to OLS with fixed effect in order to observe how far political instability hampers the vanilla exports in Madagascar. Through analysis, we find that the political instability has a negative effect on economic growth in terms of Madagascar vanilla exports.
Non-simultaneous blow-up for a semilinear parabolic system with nonlinear memory
Jun Zhou
Surveys in Mathematics and its Applications , 2007,
Abstract: In this note, we study the possibility of non-simultaneous blow-up for positive solutions to the following system: ut - u = uq1∫0t vp1(x,s) ds, vt - v = vq2∫0t up2(x,s) ds Under appropriate hypotheses, we prove that u blows up while v fails to blow up if and only if q1 > 1 and p2 < 2q1-1).
Global Existence and Blowup for a Reaction-Diffusion System with Nonlocal Boundary Condition
Jun Zhou
ISRN Mathematical Analysis , 2013, DOI: 10.1155/2013/852902
Abstract: This paper considers the singularity properties of positive solutions for a reaction-diffusion system with nonlocal boundary condition. The conditions on the existence and nonexistence of global positive solutions are given. Moreover, we establish the blow-up rate estimate for the blow-up solution. 1. Introduction This paper studies the singularity properties of the following reaction-diffusion system with nonlocal boundary condition: where is a bounded domain of , , with smooth boundary and is the closure of . , and are positive numbers which ensure that the equations in (1) are completely coupled with the nonlinear reaction terms. The functions defined for , are nonnegative and continuous. The initial values and are nonnegative, which are mathematically convenient and currently followed throughout the paper. We also assume that satisfies the compatibility condition on , and that and for any for the sake of the meaning of nonlocal boundary. Denote that , , and , where . A pair of functions is called a classical solution of problem (1) if for some , , and satisfies (1). The local existence of classical solution of (1) is standard (see [1, 2]). If , it is easy to see , and we say that the solution of problem (1) blows up at finite time . If , is called a global solution of problem (1). Over the past few years, many physical phenomena were formulated as nonlocal mathematical models (see [3, 4]). It has also being suggested that nonlocal growth terms present a more realistic model in physics for compressible reactive gases. Problem (1) arises in the study of the heat transfer with local source (see [5, 6]) and in the study of population dynamics (see [7, 8]). In recent years many authors have investigated the following initial boundary value problem of reaction-diffusion system: with Dirichlet, Neumanns or Robin boundary condition, which can be used to describe heat propagation on the boundary of container (see [2, 4, 9–23] and the literatures cited therein). Specially, when have the form a classical result is (see [9, 10, 12, 20]). Theorem A. The system (2) ( is of the form (3)) with homogenous Dirichlet boundary condition admits a unique global solution for any nonnegative initial data if and only if , , and . However, there are some important phenomena formulated as parabolic equations which are coupled with nonlocal boundary conditions in mathematical modeling such as thermoelasticity theory (see [24–26]). In this case, the solution could be used to describe the entropy per volume of the material. The problem of nonlocal boundary conditions for linear
Neural differentiation of allogenic mixed-cultured rat bone mesenchymal stem cells  [PDF]
Jun Zhou, Huilin Yang, Jiannong Cen
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.64058
Abstract:

Many studies showed that bone mesenchymal stem cells (BMSCs) can transdifferentiate to neural cell in vitro. The purpose of this study was to investigate the mixed-culture of allogenic rat BMSCs in vitro, and to perform neural differentiation potential characterization. Rat BMSCs were isolated and cultured by plastic adherence and density gradient centrifugation respectively, and the 3rd passage cells were harvested and mixed-cultured with same concentration. The second passage cells of the mixed-cultured cells were obtained to perform Wright-Gemsa staining for morphological observation, to identify the surface marker of CD29, CD45, CD90 by flow cytometry and induced to differentiate into neural cell, then performed immunocytochemistry of Nestin, NSE and GFAP. Results showed that after Wright-Giemsa staining, the mixed-cultured cells displayed typical spindle-shape, presented layered and whirlpool-like growth; and the mixed-cultured cells were positive for CD29 and CD90, but negative for CD45 by flow cytometry. After induction, the mixed-cultured cells appeared morphological changes of neuron and glial cell, and were positive expression of Nestin, neuron specific enolase (NSE) and glial fibrillary acidic protein (GFAP). The results demonstrated that the mixed-cultured allogenic rat BMSCs can be induced into neural cell such as neuron and glial cell in vitro.

A Liability Division Method for Harmonic Pollution Based on Line-Transferred Power Components  [PDF]
Jianchun Peng, Jun Zhou, Hui Jiang
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.34035
Abstract:

The existing liability division methods for harmonic pollution are either inexplicit or incomplete in physical meaning. To compensate these defects, two new methods are proposed based on line-transferred power components in this paper. At first, all harmonic sources are represented by ideal equivalent current source, line current components and bus voltage components of a source are determined by stimulation of this source with all other sources disabled. Then, the line-trans- ferred power component owing to a source under all sources action together is determined by the theory of line-transferred power components, and called source’s line-transferred power component. At last, the liability of a source for line-end harmonic pollution is divided by two methods: the ration of the source’s line-transferred active power component to the total line-transferred power, and the ration of projection of the source’s line-transferred complex power component to absolute value of the total line-transferred complex power. These two methods are taken into account not only harmonic voltage but also harmonic current in the liability division. Simulation results show that the proposed liability division method based on active power component is the most effective and ideal one.

Effect of Construction Method on Shear Lag in Prestressed Concrete Box Girders
Shi-Jun Zhou
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/273295
Abstract: Most of the previous researches conducted on shear lag of box girders were only concerned about simple types of structures, such as simply supported and cantilever beams. The structural systems concerned in these previous researches were considered as determined and unchangeable. In this paper, a finite element method considering shear lag and creep of concrete was presented to analyze the effect of dynamic construction process on shear lag in different types of concrete box-girder bridges. The shear lag effect of the three types of a two-span continuous concrete beam classified by construction methods was analyzed in detail according to construction process. Also, a three-span prestressed concrete box-girder bridge was analyzed according to the actual construction process. The shear lag coefficients and stresses on cross sections along the beam including shear lag were obtained. The different construction methods, the changes of structural system with the construction process, the changes of loading and boundary conditions with the construction process and time, the prestressing, and creep were all imitated in the calculations. From comparisons between the results for beams using different construction methods, useful conclusions were made.
Application of a new TLC chemical method for detection of cyclopeptides in plants
Jun Zhou,Ninghua Tan
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02886288
Abstract: Cyclopeptides have been investigated phytochemically less often because until now there has not been a special chemical method to detect them. Since we found cyclopeptides inPseudostellaria heterophylla (Caryophyllaceae) in 1991, we have gradually established a special chemical detection method for detecting cyclopeptides in plants, which induces a new thin layer chromatography (TLC) protosite reaction with ninhydrin reagent. With this method, our group isolated and determined 73 cyclopeptides from 17 plants which belong to 5 families and 14 genuses, they are from dicyclopeptides to undecacyclopeptides, including 68 new ones, and were determined based on spectral, chemical and enzymic methods, especially 2D NMR and FAB-MS. Meantime, with this method cyclopeptides can be distinguished from peptidic amides based on their behaviour in TLC.
Discussion and Realization of User Power Management in Large Information System
大型信息系统用户权限管理的探讨与实现

ZHOU Jun,
周俊

计算机应用研究 , 2004,
Abstract: Based on a information project in cotton textile enterprise,analyses the security of enterprise information system and details the user power mangement in large information system,presents and realizes the security control model based on role-level,department-level and user-level in the application.After practical use,it anhances better the security and maintainability of information system.
Skill Ontology for Mechanical Design of Learning Contents
Jun Zhou,Keiichi Watanuki
Journal of Software , 2012, DOI: 10.4304/jsw.7.1.61-67
Abstract: In recent years, the effect of globalization environment, and the aging of engineers and skill workers have tremendously changed the manufacture industry, therefore, transfer of technology and skill has become a very important issue. Parallel with the advancement of the Internet, e-learning systems stress on the learning of knowledge, skill transfer is rarely mentioned. In this paper, we propose a skill ontology that consists of metadata and relationships among metadata. With the skill ontology, the document can be shared, inter-operated and thus increase the efficiency of learning process.
Preoperative invasive staging for N2 Non-small cell lung cancer
Zuli ZHOU,Jun WANG
Chinese Journal of Lung Cancer , 2008,
Abstract:
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