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We discuss the problem related to the long time behavior of solutions of the partly dissipative reaction-diffusion equations in unbounded domain,and prove the existence of the compact attractors.The coefficient of the reaction-term depends on space variables,which extend Wang B and Marion M's results.  相似文献   

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A class of pattern formation equations is treated, the existence of its global attractor is considered and some estirnates of its dimension are given. This sort of pattern formation equations relate to turbulence phenomenon in chemistry and combustion, so it is of great physical importance. Besides, its important theoretical value lies in that the equation contains differential operator of the fourth order in space. The global attractor exists after a series sophisticated estimates by the means of interpolation inequity and embedding theorems in sobolev spaces. Furthermore, some estimates on its fractal dimension are given.  相似文献   

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This paper discusses the initial value problem of the nonlinear evolution equation. The uniqueness and stability of the solutions for the problem are proved. It is also obtained that the solution of the problem blows up in a finite time.  相似文献   

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非线性方程最优拟合的缩张算法   总被引:22,自引:3,他引:19  
顾世梁  惠大丰 《作物学报》1998,24(5):513-519
本文提出一种可实现非线性方程最优拟合的新方法-缩张算法(C-E算法)。该算法由若干循环组成,每一循环都包含收缩和扩张两个步骤。因而,可以在多维起始空间的内、外漫游搜索目标函数,并利用搜索过程所反馈的信息调整搜索中心和步长;通过较少次C-E循环的搜索,便能逼近给定非线性方程的最适参数值。该算法不需要给出方程的导数或偏导数,减少了计算的复杂性,也可能推广应用于解决其它目标函数的最优化问题。  相似文献   

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The microcosmical study on many speciments of sedimentary rock by SEM and petrography theory show that rock is formed of microcrystalline and micropore with all kinds of forms.Therefrom the microstructure model of rock is established.Further the three dimensional nonlinear damage constitutive equation and damage evolution equation of layered rock including respective process of damage evolution,mechanical parameter,effective stresses,and unequal biaxial stress in different rocks are derived.The results of the experiment indicate that the theoretical curve is fairly close to the experimental curve.  相似文献   

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Partial functional differential equations come from many mathematical models in physics,biology,engineering and other fields,which have strongly practical background.The oscillation theory is the one of the important branches of qualitative theory of partial functional differential equations. Therefore,it is of great theoretical and practical value to research the oscillation of partial functional differential equations.The anthors study the oscillation of the systems of a class of high order nonlinear delay partial functional differential equations.By using Green's theorem and Riccati transformation,they obtain some sufficient criteria for oscillation of all solutions of the systems under two kinds of different boundary value conditions,which are illustrated by some examples.These results offer the foundation of mathematical theory for solving the practical problems of the above fields.  相似文献   

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The static absolute position principle of Global Position System(GPS) is analyzed.The more strict equations of the GPS static absolute position are obtained,by considering the effect of the transmission of signal in earth's gravitation,on the condition that the earth's gravitation is static and spherically symmetric.The satellites' mass can be ignored and the satellites move in circular orbits.The effects of the other celestial bodies on the space-time can be neglected.And then the values of the correction quantities is estimated.The correction quantities are very small,about at the orders of magnitude from mm to cm.Moreover,the current GPS's corrections to the satellite clocks are not correspondent theoretically with the theory of measurement of general relativity.  相似文献   

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茶树[Camellia sinensis (L.) O. Kuntze]起源于我国的西南地区,在由起源地向我国其他地区和世界其他地区传播的过程中,发生了从形态学水平到细胞水平再到分子水平的一系列演化。对茶树遗传演化的研究,是茶树基础生物学的一个基本问题,也是茶树种质资源研究的重要方面。近年来,各种新技术、新方法被广泛应用于研究茶树遗传演化关系,取得了一定的进展。本文从形态学、细胞学、生物化学、分子生物学方面对茶树遗传演化研究取得的进展进行了综述,分析了SSR标记在植物遗传演化中的应用,探讨了SSR标记在茶树遗传演化研究中的应用前景,旨为进一步深入研究我国茶树遗传多样性、亲缘关系及演化路径分析提供参考。  相似文献   

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黄杨属植物ITS序列分子进化特点分析   总被引:1,自引:0,他引:1  
黄杨属植物种类多,分类较为混乱,特别是中国特有种珍珠黄杨的分类地位和系统进化存有争议,鉴于此,本文选取黄杨属5种植物和珍稀濒危植物珍珠黄杨的5个居群,对其rDNA ITS序列分析,结合GenBank中报道的黄杨属其它9个种,以板凳果属顶花板凳果的ITS序列为参照,用成对比较的方法对黄杨属18种植物的ITS序列比较发现,...  相似文献   

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With the attention to the comfort degree of living environment, the phenomenon of making use of the PMV -PPD index within the ISO7730 standard to evaluate the indoor thermal comfort degree is more and more widespread. Many papers about indoor thermal environment are based on the PMV - PPD index as the reference or basis to research and analyze. But few people understand and pay attention to the application range of the PMV - PPD index. So some people misuse and abuse the PMV index and deduce some inaccurate conclusions. In this thesis, based on the analysis of the process of deducing PMV equation, the phenomenon that PMV index is different from the fact in the high temperature condition is explained; furthermore the application range of the PMV equation is confirmed. So to obtain the scientific and reasonable evaluation and conclusion in the process of research of the thermal comfort degree can be ensured.  相似文献   

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The aufhors calculate and analyze the arcing grounding overvoltage of 10 kV power network in case of neutral ungrounded and grounding through nonlinear resistance using EMTP, with a actual 10 kV power network of a substation in Guizhou province as an example. The emulational calculation results show that the grounding method which grounds through nonlinear resisitance has the advantages of the other two methods, can better limit the arcing grounding overvoltage and can not stop the power supply .even one phase is grounded by fault, so it can ensure the security of the power networkg supply . the network neutral grounding through nonlinear resistance needs more deep study and analysis as a new network neutral grounding mehtod.  相似文献   

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