研究旨在探讨丁酸甘油酯对断奶仔猪生长性能和腹泻率的影响,运用Meta分析方法进行系统评价。经检索万方、中国知网、维普、Pub Med和Web of Science数据库,搜索丁酸甘油酯对断奶仔猪生长性能影响的文献,按照纳入和排除标准筛选文献、提...研究旨在探讨丁酸甘油酯对断奶仔猪生长性能和腹泻率的影响,运用Meta分析方法进行系统评价。经检索万方、中国知网、维普、Pub Med和Web of Science数据库,搜索丁酸甘油酯对断奶仔猪生长性能影响的文献,按照纳入和排除标准筛选文献、提取资料,用Review Manager 5.4软件进行Meta分析。共纳入12个研究,样本838例。结果显示:丁酸甘油酯组的平均日增重显著高于空白组(P<0.0001,SMD=1.58,95%CI:0.80~2.36),平均日采食量与空白组差异不显著(P=0.30,SMD=-0.44,95%CI:-1.28~0.40),料重比显著低于空白组(P=0.0002,SMD=-0.85,95%CI:-1.29~-0.40),腹泻率显著低于空白组(P=0.0003,SMD=-2.78,95%CI:-4.27~-1.28)。说明饲料中添加丁酸甘油酯可显著提高断奶仔猪的平均日增重,降低料重比和腹泻率,建议丁酸甘油酯添加量为1%~2%。展开更多
In this paper the following nonlinear degenerate parabolic systemsu t=Δ x( grad φ(u))+α·Δb(u)+f(x,t,u)with Dirichlet boundary conditions are discussed, where u, grad φ(u),b and f are vector value...In this paper the following nonlinear degenerate parabolic systemsu t=Δ x( grad φ(u))+α·Δb(u)+f(x,t,u)with Dirichlet boundary conditions are discussed, where u, grad φ(u),b and f are vector valued functions and x∈Ω R N. Under some structure conditions on the terms of the systems, the results on existence and uniqueness of global solutions of the systems are established.展开更多
In this paper we consider the following problem ui=△u^m+bi(u^n)x Letu=u(x,t)be a continuous weak solution of the equation in R^N×(0,T)for someT>0.Then we conclude;Corresponding to u there is a unique nonnega...In this paper we consider the following problem ui=△u^m+bi(u^n)x Letu=u(x,t)be a continuous weak solution of the equation in R^N×(0,T)for someT>0.Then we conclude;Corresponding to u there is a unique nonnegative Borel measure v on R^Nwhich is the initial trace of u;there is the global inequality of Harnack type for u;the initial tracev must belong to a certain growth class;consequently,by combining the results mentioned above a u-niqueness conclusion is established.展开更多
In this paper we osider the following prolemut=△u^m+bi(u^n)xi where the summation convention is used.We call the equation as porous medium equation with convection.Letu=u(x,t)be a continuous weak solution of the equa...In this paper we osider the following prolemut=△u^m+bi(u^n)xi where the summation convention is used.We call the equation as porous medium equation with convection.Letu=u(x,t)be a continuous weak solution of the equation in R^N×(0,T)]for someT>0,Then we can establish BPC estimates and the intrinsic Harnack inequality for the solution of the equation just as the standard equation discussed by other authors previously.This work lay a main foundation of studying other properties of this problem further.展开更多
In this paper we study the source-type solution for the heat equation with convection： ut = △u ＋ b·▽un for （x,t） ∈ ST→ RN × （0,T] and u（x,0） = δ（x） for x ∈ RN, where δ（x） denotes Dirac meas...In this paper we study the source-type solution for the heat equation with convection： ut = △u ＋ b·▽un for （x,t） ∈ ST→ RN × （0,T] and u（x,0） = δ（x） for x ∈ RN, where δ（x） denotes Dirac measure in = RN,N 2,n 0 and b = （b1,...,bN） ∈ RN is a vector. It is shown that there exists a critical number pc = N＋2 such that the source-type solution to the above problem exists and is unique if 0 N n 〈 pc and there exists a unique similarity source-type solution in the case n = N＋1 , while such a solution does not exist N if n 〉 pc. Moreover, the asymptotic behavior of the solution near the origin is studied. It is shown that when 0 〈 n 〈 N＋1 the convection is too weak and the short time behavior of the source-type solution near the origin N is the same as that for the heat equation without convection.展开更多
In this paper, we consider the following equation ut=（um）xx＋（un）x, with the initial condition as Dirac measure. Attention is focused on existence, nonexistence, uniqueness and the asymptotic behavior near （0,0）...In this paper, we consider the following equation ut=（um）xx＋（un）x, with the initial condition as Dirac measure. Attention is focused on existence, nonexistence, uniqueness and the asymptotic behavior near （0,0） of solution to the Cauchy＇s problem. The special feature of this equation lies in nonlinear convection effect, i.e., the equation possesses nonlinear hyperbolic character as well as degenerate parabolic one. The situation leads to a more sophisticated mathematical analysis. To our knowledge, the solvability of singular solution to the equation has not been concluded yet. Here based on the previous works by the authors, we show that there exists a critical number n0=m＋2 such that a unique source-type solution to this equation exists if 0≤n展开更多
In this paper we study a nonlinear Maxwell＇s system in a highly conductive medium in which the displacement current is neglected. The magnetic field H satisfies a quasilinear evolution system： Ht＋△↓×[r（x,t,...In this paper we study a nonlinear Maxwell＇s system in a highly conductive medium in which the displacement current is neglected. The magnetic field H satisfies a quasilinear evolution system： Ht＋△↓×[r（x,t,｜H｜,｜△↓×H｜）△↓×H]=F（x,t,H）,where the resistivity r is assumed to depend upon the strengths of electric and magnetic fields while the internal magnetic current F depends upon the magnetic field. It is shown that under appropriate structure conditions for r and F the above nonlinear system subject to appropriate initial-boundary conditions has a unique global solution.展开更多
文摘In this paper the following nonlinear degenerate parabolic systemsu t=Δ x( grad φ(u))+α·Δb(u)+f(x,t,u)with Dirichlet boundary conditions are discussed, where u, grad φ(u),b and f are vector valued functions and x∈Ω R N. Under some structure conditions on the terms of the systems, the results on existence and uniqueness of global solutions of the systems are established.
文摘In this paper we consider the following problem ui=△u^m+bi(u^n)x Letu=u(x,t)be a continuous weak solution of the equation in R^N×(0,T)for someT>0.Then we conclude;Corresponding to u there is a unique nonnegative Borel measure v on R^Nwhich is the initial trace of u;there is the global inequality of Harnack type for u;the initial tracev must belong to a certain growth class;consequently,by combining the results mentioned above a u-niqueness conclusion is established.
文摘In this paper we osider the following prolemut=△u^m+bi(u^n)xi where the summation convention is used.We call the equation as porous medium equation with convection.Letu=u(x,t)be a continuous weak solution of the equation in R^N×(0,T)]for someT>0,Then we can establish BPC estimates and the intrinsic Harnack inequality for the solution of the equation just as the standard equation discussed by other authors previously.This work lay a main foundation of studying other properties of this problem further.
基金supported by National Natural Science Foundation of China (Grant Nos.10671103, 11001142)the Natural Science Foundation of Fujian Province (Grant No. S0650027)
文摘In this paper we study the source-type solution for the heat equation with convection： ut = △u ＋ b·▽un for （x,t） ∈ ST→ RN × （0,T] and u（x,0） = δ（x） for x ∈ RN, where δ（x） denotes Dirac measure in = RN,N 2,n 0 and b = （b1,...,bN） ∈ RN is a vector. It is shown that there exists a critical number pc = N＋2 such that the source-type solution to the above problem exists and is unique if 0 N n 〈 pc and there exists a unique similarity source-type solution in the case n = N＋1 , while such a solution does not exist N if n 〉 pc. Moreover, the asymptotic behavior of the solution near the origin is studied. It is shown that when 0 〈 n 〈 N＋1 the convection is too weak and the short time behavior of the source-type solution near the origin N is the same as that for the heat equation without convection.
基金National Natural Science Foundation of China (Grant Nos. 10671103 and 11001142)
文摘In this paper, we consider the following equation ut=（um）xx＋（un）x, with the initial condition as Dirac measure. Attention is focused on existence, nonexistence, uniqueness and the asymptotic behavior near （0,0） of solution to the Cauchy＇s problem. The special feature of this equation lies in nonlinear convection effect, i.e., the equation possesses nonlinear hyperbolic character as well as degenerate parabolic one. The situation leads to a more sophisticated mathematical analysis. To our knowledge, the solvability of singular solution to the equation has not been concluded yet. Here based on the previous works by the authors, we show that there exists a critical number n0=m＋2 such that a unique source-type solution to this equation exists if 0≤n
文摘In this paper we study a nonlinear Maxwell＇s system in a highly conductive medium in which the displacement current is neglected. The magnetic field H satisfies a quasilinear evolution system： Ht＋△↓×[r（x,t,｜H｜,｜△↓×H｜）△↓×H]=F（x,t,H）,where the resistivity r is assumed to depend upon the strengths of electric and magnetic fields while the internal magnetic current F depends upon the magnetic field. It is shown that under appropriate structure conditions for r and F the above nonlinear system subject to appropriate initial-boundary conditions has a unique global solution.
