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Search Results: 1 - 10 of 16351 matches for " Xiaojie Qi "
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Error estimates of finite element method for semi-linear stochastic strongly damped wave equation
Ruisheng Qi,Xiaojie Wang
Mathematics , 2015,
Abstract: In this paper, we consider a semi-linear stochastic strongly damped wave equation driven by additive Gaussian noise. Following a semigroup framework, we establish existence, uniqueness and space-time regularity of a mild solution to such equation. Unlike the usual stochastic wave equation without damping, the underlying problem with space-time white noise (Q = I) allows for a mild solution with a positive order of regularity in multiple spatial dimensions. Further, we analyze a spatio-temporal discretization of the problem, performed by a standard finite element method in space and a well-known linear implicit Euler scheme in time. The analysis of the approximation error forces us to significantly enrich existing error estimates of semidiscrete and fully discrete finite element methods for the corresponding linear deterministic equation. The main results show optimal convergence rates in the sense that the orders of convergence in space and in time coincide with the orders of the spatial and temporal regularity of the mild solution, respectively. Numerical examples are finally included to confirm our theoretical findings.
Research on the Trans-Regional Integration of Chinese Family Enterprise Based on the Perspective of Organizational Trust and Control
—A Case Study of Hope Group
 [PDF]

Sheng Xu, Xiaojie Huang
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.312009
Abstract: Under the background of Chinese Regional Market Segmentation and Familism Dilemma, this article deeply analyses Hope Group with the method of case study and then demonstrates the relationship between the trans-regional market scope, organizational trust and control. The result shows that, on the one hand, the market scope influences the way of control directly, that is, with the expansion of the market, family enterprise tends to adopt formal control rather than informal control. On the other hand, the scope of trans-regional market integration affects the way of organizational control indirectly by having an influence on organizational trust. With the enlargement of market scope, the evolution of organization trust helps to optimize control mode and finally achieve the integration of formal control and informal control in China’s family enterprise.
Analysis of the Problems and Countermeasures of China’s Green Credit  [PDF]
Xiaojie Wu, Xuehua Zhang
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.66009
Abstract: At present, China’s green credit market is the most important channel for green financing and has a great influence on the development of China’s green finance. Based on the collection and arrangement of the related data and information, the paper points out the main problems which is existing in China’s green credit by figures and examples from aspects of detail standards of policies, the matching level between deposits and loans and the management ability of avoiding environmental risk. Furthermore, the paper puts forward corresponding countermeasures of the problems.
Directed DNA Shuffling of Retrovirus and Retrotransposon Integrase Protein Domains
Xiaojie Qi, Edwin Vargas, Liza Larsen, Whitney Knapp, G. Wesley Hatfield, Richard Lathrop, Suzanne Sandmeyer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063957
Abstract: Chimeric proteins are used to study protein domain functions and to recombine protein domains for novel or optimal functions. We used a library of chimeric integrase proteins to study DNA integration specificity. The library was constructed using a directed shuffling method that we adapted from fusion PCR. This method easily and accurately shuffles multiple DNA gene sequences simultaneously at specific base-pair positions, such as protein domain boundaries. It produced all 27 properly-ordered combinations of the amino-terminal, catalytic core, and carboxyl-terminal domains of the integrase gene from human immunodeficiency virus, prototype foamy virus, and Saccharomyces cerevisiae retrotransposon Ty3. Retrotransposons can display dramatic position-specific integration specificity compared to retroviruses. The yeast retrotransposon Ty3 integrase interacts with RNA polymerase III transcription factors to target integration at the transcription initiation site. In vitro assays of the native and chimeric proteins showed that human immunodeficiency virus integrase was active with heterologous substrates, whereas prototype foamy virus and Ty3 integrases were not. This observation was consistent with a lower substrate specificity for human immunodeficiency virus integrase than for other retrovirus integrases. All eight chimeras containing the Ty3 integrase carboxyl-terminal domain, a candidate targeting domain, failed to target strand transfer in the presence of the targeting protein, suggesting that multiple domains of the Ty3 integrase cooperate in this function.
Existence of Solutions to a Nonlocal Boundary Value Problem with Nonlinear Growth
Xiaojie Lin
Boundary Value Problems , 2011, DOI: 10.1155/2011/416416
Abstract:
Existence of Solutions to a Nonlocal Boundary Value Problem with Nonlinear Growth
Lin Xiaojie
Boundary Value Problems , 2011,
Abstract: This paper deals with the existence of solutions for the following differential equation: , , subject to the boundary conditions: , , where , , is a continuous function, is a nondecreasing function with . Under the resonance condition , some existence results are given for the boundary value problems. Our method is based upon the coincidence degree theory of Mawhin. We also give an example to illustrate our results.
Analysis of a Model Arising from Invasion by Precursor and Differentiated Cells
Xiaojie Hou
International Journal of Differential Equations , 2013, DOI: 10.1155/2013/341473
Abstract: We study the wave solutions for a degenerated reaction diffusion system arising from the invasion of cells. We show that there exists a family of waves for the wave speed larger than or equal a certain number and below which there are no monotonic wave solutions. We also investigate the monotonicity, uniqueness, and asymptotics of the waves. 1. Introduction In [1], the following coupled partial differential equation system was proposed to study the invasion by precursor and differentiated cells: where denotes the population densities of the precursor cells. The constant is the diffusion rate of the cell , which has proliferation rate , and is the carrying capacity of . The parameter measures the relative contribution that the differentiated cell with population density makes to the carrying capacity . The cell population density is limited by its carrying capacity and has a maximum differentiation rate . The model assumes that the differentiated cells do not have mobility. By letting (see [1]) and dropping the hat notation for convenience, system (1) is changed into where and . System (1) or (3) belongs to reaction diffusion systems of degenerate type, and such systems have attracted much attention in research fields such as epidemics and wound healing [2–4] as well as combustion and calcium wave problems [5–8]. However, system (3) differs from the above systems in the appearance of degenerate reaction terms. In fact, coupling with any consists of a constant solution of (3). This resembles the combustion wave equation considered in [9]; however, our method in proving the existence of the fronts of (3) differs from theirs. If the parameters satisfy then system (3) admits an additional equilibrium: representing the state that the spatial domain is successfully invaded. We also separate the equilibrium from the rest of the line of equilibria, . The unstable equilibrium represents the state before the invasion. We are interested in the existence of the wave solutions connecting with as time and space evolve from to . Setting , , , a traveling wave solution to (3) solves with boundary conditions: For the notational convenience, we further set and drop the bar on to have Numerical investigations [1] strongly suggest that system (10) and (9) admit traveling wave solutions for and . When the differentiated cell density does not affect the proliferation of the precursor cells, we have ; when the total cell population contributes to the proliferation carrying capacity, we have . Numerically, however, when , (8) may have nonmonotone traveling wave solutions and
Analysis of a model arising from invasion by precursor and differentiated cells
Xiaojie Hou
Mathematics , 2013,
Abstract: We study the wave solutions for a degenerated reaction diffusion system arising from the invasion of cells. We show that there exists a family of waves for the wave speed larger than or equals a certain number, and below which there is no monotonic wave solutions. We also investigate the monotonicity, uniqueness and asymptotics of the waves.
An exponential integrator scheme for time discretization of nonlinear stochastic wave equation
Xiaojie Wang
Mathematics , 2013, DOI: 10.1007/s10915-014-9931-0
Abstract: This work is devoted to convergence analysis of an exponential integrator scheme for semi-discretization in time of nonlinear stochastic wave equation. A unified framework is first set forth, which covers important cases of additive and multiplicative noises. Within this framework, the proposed scheme is shown to converge uniformly in the strong $L^p$-sense with precise convergence rates given. The abstract results are then applied to several concrete examples. Further, weak convergence rates of the scheme are examined for the case of additive noise. To analyze the weak error for the nonlinear case, techniques based on the Malliavin calculus were usually exploited in the literature. Under certain appropriate assumptions on the nonlinearity, this paper provides a weak error analysis, which does not rely on the Malliavin calculus. The rates of weak convergence can, as expected, be improved in comparison with the strong rates. Both strong and weak convergence results obtained here show that the proposed method achieves higher convergence rates than the implicit Euler and Crank-Nicolson time discretizations. Numerical results are finally reported to confirm our theoretical findings.
Weak error estimates of the exponential Euler scheme for semi-linear SPDEs without Malliavin calculus
Xiaojie Wang
Mathematics , 2014, DOI: 10.3934/dcds.2016.36.xx
Abstract: This paper deals with the weak error estimates of the exponential Euler method for semi-linear stochastic partial differential equations (SPDEs). A weak error representation formula is first derived for the exponential integrator scheme in the context of truncated SPDEs. The obtained formula that enjoys the absence of the irregular term involved with the unbounded operator is then applied to a parabolic SPDE. Under certain mild assumptions on the nonlinearity, we treat a full discretization based on the spectral Galerkin spatial approximation and provide an easy weak error analysis, which does not rely on Malliavin calculus.
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