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Search Results: 1 - 10 of 22955 matches for " YUAN Zhenyi "
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ZHANG Zhifang,YUAN Zhenyi,TIAN Changsheng,

金属学报 , 1983,
Abstract: An investigation was made of the dynamic recrystallization of TC6 Ti alloy by optical microscope and TEM. The three-dimensional dynamic recrystallization diagram of the alloy was establisbed and the optimum hot-deformation parameters for a uniform and fine size grain were determined. An discussion on the experimental results together with the static recrystallization theory is described.
Qualitative properties of solutions for quasi-linear elliptic equations
Zhenyi Zhao
Electronic Journal of Differential Equations , 2003,
Abstract: For several classes of functions including the special case $f(u)=u^{p-1}-u^m$, $m>p-1>0$, we obtain Liouville type, boundedness and symmetry results for solutions of the non-linear $p$-Laplacian problem $-Delta_p u=f(u)$ defined on the whole space $mathbb{R}^n$. Suppose $u in C^2(mathbb{R}^n)$ is a solution. We have that either (1) if $u$ doesn't change sign, then $u$ is a constant (hence, $uequiv 1$ or $uequiv 0$ or $uequiv-1$); or (2) if $u$ changes sign, then $uin L^{infty}(mathbb{R}^n)$, moreover $|u|<1$ on $mathbb{R}^n$; or (3) if $|Du|>0$ on $mathbb{R}^n$ and the level set $u^{-1}(0)$ lies on one side of a hyperplane and touches that hyperplane, i.e., there exists $ u in S^{n-1}$ and $x_{0}in u^{-1}(0)$ such that $ u cdot (x-x_0)geq 0$ for all $xin u^{-1}(0)$, then $u$ depends on one variable only (in the direction of $ u$).
Language Evolution in Biolinguistics from a Multi-Factor Perspective  [PDF]
Zhenyi Shao
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1105867
Biolinguistics is an interdisciplinary subject derived from the interaction of biology and linguistics. In 1967, after the publication of Biological Foundations of Language by Lenneberg E.H., the vision of Language study has been introduced into the field of biology. Later, Chomsky proposed the term of language faculty and regarded language as “an organ of the body”. Different from traditional linguists’ description of the rules of language externalization, Chomsky focuses on the biological mechanism of internalized language. The challenge of theory of evolution in biology has also enriched the study of the origin and evolution of language. This thesis will begin with the mythological origin and philosophical foundation of language, chase the challenge of evolutionary theory, and discuss two groups of basic properties of language, which is unity and diversity, recursiveness and thinking, so as to further study the relation between language and its biological basis, that is, from language and speech organ, language and thought to language and gene, to analyze the uniqueness of human language competence.
An improvement upon unmixed decomposition of an algebraic variety
Zhenyi Ji,Yongbin Li
Mathematics , 2010,
Abstract: Decomposing an algebraic variety into irreducible or equidimensional components is a fundamental task in classical algebraic geometry and has various applications in modern geometry engineering. Several researchers studied the problem and developed efficient algorithms using $Gr$\"{o}$bner$ basis method. In this paper, we try to modify the computation of unmixed decomposition of an algebraic variety based on improving the computation of $Zero(sat(\mathbb{T}))$, where $\mathbb{T}$ is a triangular set in $\textbf{K[X]}$.
Semistability-Based Robust and Optimal Control Design for Network Systems
Qing Hui,Zhenyi Liu
Mathematics , 2014,
Abstract: In this report, we present a new Linear-Quadratic Semistabilizers (LQS) theory for linear network systems. This new semistable H2 control framework is developed to address the robust and optimal semistable control issues of network systems while preserving network topology subject to white noise. Two new notions of semistabilizability and semicontrollability are introduced as a means to connecting semistability with the Lyapunov equation based technique. With these new notions, we first develop a semistable H2 control theory for network systems by exploiting the properties of semistability. A new series of necessary and sufficient conditions for semistability of the closed-loop system have been derived in terms of the Lyapunov equation. Based on these results, we propose a constrained optimization technique to solve the semistable H2 network-topology-preserving control design for network systems over an admissible set. Then optimization analysis and the development of numerical algorithms for the obtained constrained optimization problem are conducted. We establish the existence of optimal solutions for the obtained nonconvex optimization problem over some admissible set. Next, we propose a heuristic swarm optimization based numerical algorithm towards efficiently solving this nonconvex, nonlinear optimization problem. Finally, several numerical examples will be provided.
Direct versus Indirect Herbicide Effects: The Example of Preplant Incorporated Halosulfuron  [PDF]
Zhenyi Li, Rene Van Acker, Nader Soltani, Peter H. Sikkema
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.84044
Abstract: The potential indirect effects of soil applied herbicides have not been adequately explored. The objective of this study was to explore the potential and relative importance of the indirect effects of halosulfuron applied preplant incorporated (PPI) on several weed species common in white bean fields in Ontario. Halosulfuron applied PPI at 35 g ai ha-1 delayed common lambsquarters and wild mustard emergence and reduced their densities over 70%. It did not delay green foxtail emergence, but the density was decreased over 30%. Indirect herbicidal effects such as delayed emergence timing may be important for weed management in non-competitive crops such as white bean. Based on these results, the indirect effects of soil applied herbicides are real and are potentially important for providing additional prevention of yield loss in field crops. This may be particularly important for relatively non-competitive crops such as white bean and for reducing weed seed return to the seedbank.
Ischemia-Induced Apoptosis of Intestinal Epithelial Cells Correlates with Altered Integrin Distribution and Disassembly of F-Actin Triggered by Calcium Overload
Zhenyi Jia,Qian Chen,Huanlong Qin
Journal of Biomedicine and Biotechnology , 2012, DOI: 10.1155/2012/617539
Abstract: The present study examined intestinal epithelial cell (IEC) integrin distribution and disassembly of actin cytoskeleton in response to ischemia-anoxia. Protective effects of calcium channel blocker(CCB) were further examined to explore underlying mechanisms of cellular injury. Materials and Methods. Primary cultures of rat IECs and an in vitro model of ischemia/anoxia were established. IECs were exposed to ischemia/anoxia in the presence and absence of verapamil. The extent of exfoliation was determined using light microscopy while apoptosis rate was measured using flow cytometry. Changes in intracellular calcium, the distribution of integrins and the morphology of F-actin were assessed by confocal microscopy. Results. Detachment and apoptosis of IECs increased following ischemia/anoxia-induced injury. Treatment with verapamil inhibited the detachment and apoptosis. Under control conditions, the strongest fluorescent staining for integrins appeared on the basal surface of IECs while this re-distributed to the apical membrane in response to ischemic injury. Depolymerization of F-actin was also observed in the injured cells. Verapamil attenuated both changes of integrins and F-actin. Conclusions. Redistribution of integrins and disruption of F-actin under ischemia/anoxia injury is associated with IEC detachment and increased apoptosis. These events appeared to be triggered by an increase in Ca2
Recent Advances in Direct Coal Liquefaction
Hengfu Shui,Zhenyi Cai,Chunbao (Charles) Xu
Energies , 2010, DOI: 10.3390/en3020155
Abstract: The growing demand for petroleum, accompanied by the declining petroleum reserves and the concerns over energy security, has intensified the interest in direct coal liquefaction (DCL), particularly in countries such as China which is rich in coal resources, but short of petroleum. In addition to a general introduction on the mechanisms and processes of DCL, this paper overviews some recent advances in DCL technology with respect to the influencing factors for DCL reactions (temperature, solvent, pressure, atmospheres, etc.), the effects of coal pre-treatments for DCL (swelling, thermal treatment, hydrothermal treatment, etc.), as well as recent development in multi-staged DCL processes, DCL catalysts and co-liquefaction of coal with biomass.
Early stage morphology of quench condensed Ag, Pb and Pb/Ag hybrid films
Zhenyi Long,James M. Valles Jr
Physics , 2004, DOI: 10.1007/s10909-005-4732-3
Abstract: Scanning Tunneling Microscopy (STM) has been used to study the morphology of Ag, Pb and Pb/Ag bilayer films fabricated by quench condensation of the elements onto cold (T=77K), inert and atomically flat Highly Oriented Pyrolytic Graphite (HOPG) substrates. All films are thinner than 10 nm and show a granular structure that is consistent with earlier studies of QC films. The average lateral diameter, $\bar {2r}$, of the Ag grains, however, depends on whether the Ag is deposited directly on HOPG ($\bar {2r}$ = 13 nm) or on a Pb film consisting of a single layer of Pb grains ($\bar {2r}$ = 26.8 nm). In addition, the critical thickness for electrical conduction ($d_{G}$) of Pb/Ag films on inert glass substrates is substantially larger than for pure Ag films. These results are evidence that the structure of the underlying substrate exerts an influence on the size of the grains in QC films. We propose a qualitative explanation for this previously unencountered phenomenon.
Non-Negativity Preserving Numerical Algorithms for Problems in Mathematical Finance  [PDF]
Yuan Yuan
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.93024
We give a study result to analyze a rather different, semi-analytical numerical algorithms based on splitting-step methods with their applications to mathematical finance. As certain subsistent numerical schemes may fail due to producing negative values for financial variables which require non-negativity preserving. These algorithms which we are analyzing preserve not only the non-negativity, but also the character of boundaries (natural, reflecting, absorbing, etc.). The derivatives of the CIR process and the Heston model are being extensively studied. Beyond plain vanilla European options, we creatively apply our splitting-step methods to a path-dependent option valuation. We compare our algorithms to a class of numerical schemes based on Euler discretization which are prevalent currently. The comparisons are given with respect to both accuracy and computational time for the European call option under the CIR model whereas with respect to convergence rate for the path-dependent option under the CIR model and the European call option under the Heston model.
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