讨论了一类非线性传染病传播群体的模型,利用泛函同伦映射的方法来探求传染病的传播规律,构造一对泛函同伦映照,讨论模型相应的线性系统.在一定的情况下,在零点处是一个稳定的结点,即原流行性传染病传播系统在零点处为稳定结点.因此,系统模型的时间当变量t趋于无穷时而趋于零点(解).对于这种流行传染病传播模式,就能采取较好的措施,使传染病将得到控制.最后通过一个例子,说明了所用的方法的正确性,泛函同伦映照方法可采取对应的措施来控制它,解的表示式还能进一步进行解析运算.因此,它能够继续其它相关物理量的各种性态更深入的讨论.

讨论了一类广义非线性奇异摄动积分-微分发展方程Robin问题.首先,利用广义Fredholm积分方程求解方法,得到了模型的外部解.其次,引入多重尺度变量,构造了Robin问题解的边界层校正项.然后利用伸长变量,得到了解的初始层校正项,并构造了奇异摄动问题的形式解的合成展开式.最后,用泛函分析不动点理论证明了广义解的渐近展开式的一致有效性.

该文用泛函广义变分迭代方法,研究了一类非线性扰动动力系统.首先引入一个相应典型系统的孤立子波解.然后构造一组泛函广义变分式,求出Lagrange乘子,最后构造一组变分迭代关系式,由此便得到了原非线性扰动动力系统的渐近行波解.

A class of high-order nonlinear integral-differential singular perturbation systems’ steady state Robin problem was discussed. Firstly, the theory of differential inequality for the high-order nonlinear nonlocal differential system was built. Then, the outer solution to the problem was structured and the boundary layer corrective term was obtained by means of the local coordinate system. Thus the formal asymptotic expansion of the solution was got. Finally, the uniform validity of the asymptotic expansion of the solution was proved with the theory of differential inequality.

研究了一类分数阶广义非线性扰动热波方程.首先用奇异慑动方法,求出了分数阶广义非线性扰动热波方程初始边值问题的任意次近似解析解.然后利用泛函分析不动点定理证明了它的一致有效性,最后简述了它的物理意义.求得的近似解析解,弥补了单纯用数值方法求模拟解的不足.

讨论了一类流行性病毒传染问题,提出了传染病传播生态系统动力学模型,利用奇异摄动方法,首先构造初值问题的外部解,然后引入伸长尺度变量构造了问题解初始层校正项,最后利用合成展开理论得到了生态系统初值问题的渐近解.并利用微分方程的比较定理证明了对应的生态系统的渐近解的一致有效性,同时举出了一个例子,说明了利用奇异摄动方法得到的生态系统的渐近解具有较好的近似度.

The existence and uniqueness of solutions to the boundary value problem of a class of nonlinear 3rd-order differential equations were studied. Firstly, the results of the research on the boundary values of 3rd-order differential equations at home and abroad in recent years were combed. Then the boundary value problem of nonlinear 3rd-order differential equations with nonlinear boundary value conditions was put forth, and the solution to the related linear problem was explored. Finally, the Banach fixed point theorem was used to prove that the proposed boundary value problem has a unique solution. An example illustrates the applicability of the main results.

在全球气候变暖的极端反常的情形下,大气尘埃的扩散现象会带来巨大的灾害.本文研究了大气尘埃等离子体扩散的一类广义非线性孤立子波模型.首先对非扰动情形下利用待定系数法得到孤立子波解的解析表示式.其次用广义变分迭代的方法求出对应的变分乘子并构造变分迭代式,依次求出孤子波的各次迭代解.然后用行波变换得到广义非线性尘埃等离子体扰动模型的孤立子波的各次近似解.最后,由得到解的近似函数序列据变分理论知,在自变量的一定区域内此序列为一致收敛的.因此便证明了迭代解的极限函数是尘埃等离子体低频振动非线性方程的精确解.本文得到的近似解是尘埃等离子体的低频振动孤立子波的近似解析解,据它可用解析运算来求出相关量的物理性态,如孤立子波的波峰值.可以根据本文理论采取相应措施,避免出现电荷超高密度的聚集而导致放电击穿现象等.

A class of nonlinear fractional-order perturbed higher-order differential models was considered. Firstly, under suitable conditions, the outer solution to the original problem was obtained with the perturbation method. Then by means of the stretched variable, the composite expansion method and the theory of power series, the first and second boundary layer correction terms were constructed and the formal asymptotic expansion was obtained. Finally, with the theory of differential inequalities the asymptotic behavior of the solution to the problem was studied and the uniform validity of the asymptotic estimate expression was proved.

本文研究了一类非线性抛物型微分系统的奇异摄动问题.首先利用奇异摄动方法构造了外部解.其次,分别采用多尺度法和伸长变量法获得尖层校正项、边界层校正项和初始层校正项.最后得到了广义解的渐近展开解.利用不动点定理证明了渐近解的一致有效性.该渐近解可用于对广义解进行解析运算,可以了解其更多的特征,因此具有较好的应用前景.

A class of Robin problems of nonlinear catalytic reaction differential equations were studied. Firstly, under the suitable conditions, the outer solution to the original Robin problem was obtained with the perturbation method. Then by means of the stretched variable and the power series, the 1st and 2nd boundary layer corrective terms were constructed respectively, and the formal asymptotic expansion was structured. Finally, based on the theory of differential inequalities the formal asymptotic expression of the solution to the Robin problem was given. Finally, the uniform validity of the asymptotic expression of the solution to problem was proved.

研究了一类费米(Fermi)气体光晶格轨线模型.首先求得了费米气体光品格在典型模型轨线的精确解.然后由一组广义泛函分析变分理论,构造一组迭代系统,得到了费米气体光晶格非线性扰动模型轨线的任意次渐近解.该文在方法上较方便地得到轨线的渐近表示式.所用的方法和基本理论,具有广泛的实际应用价值.

A class of Cauchy problem for the nonlinear nonlocal singular perturbation fractional order equation was considered.First,the outer solution to the original Cauchy problem was obtained.Then,using the stretched variables and the composing expansion method the shock wave layer and initial layer were constructed.Finally,using the theory of differential inequality the asymptotic behavior of the solution to the original Cauchy problem of nonlinear nonlocal singular perturbation fractional order equation was studied and its uniformly valid asymptotic estimation was proved.

A class of nonlinear differential-integral system for the singular perturbation generalized reaction diffusion equations with time delay is considered. Under suitable conditions, the asymptotic expansions of generalized solution to the initial boundary problem is obtained by using the singular perturbation method. And the theory of differential inequality for generalized solution is constructed. Corresponding existence and the uniformly validity of the asymptotic expansion for the solution are proved.

利用广义变分迭代方法讨论了一类非线性强迫扰动Klein-Gordon方程.首先,用双曲函数待定系数法求得了无扰动方程孤子波.其次,利用泛函变分迭代原理得到了强迫扰动Klein-Gordon方程的一个摄动近似解.最后,论述了解的一致有效性.得到的近似解是解析式,它可对近似解进行解析运算,这对用简单的模拟方法得到的近似解是达不到的.

本文讨论了一类非线性广义Sine-Gordon扰动方程,基于渐近理论得到对应方程的时滞初值问题并求出渐近解析解.首先,利用Fourier变换方法得出外部解.其次,按时滞变量展开扰动函数,再根据摄动方法和理论求出强阻尼时滞扰动广义Sine-Gordon方程初值问题的的渐近解.根据本文的理论和方法得到的渐近解是解析的表示式,能够进行解析运算,从而可得到相关的物理量的性状,扩大了问题的讨论范围.

研究了一类非线性广义热波方程.首先在简化的热波方程情形下求得解,其次用泛函分析同伦映射方法,求出了广义非线性扰动热波方程初始-边值问题任意次的渐近解.并举例求得了其渐近解以及解的精度.最后简述了它的物理意义.并说明了它是近似的解析解,弥补了单纯用数值方法模拟解的不足.

描述了一类厄尔尼诺/拉尼娜-南方涛动(ENSO)动力系统.首先求得了退化模型的解,其次对方程的时滞函数作了处理,然后利用摄动方法得到了对应问题的渐近解.最后,研究了模型的参数对振子系统的影响并做出了对应的曲线图形,同时对系统的物理量的变化作了描述.

探讨了一类量子等离子体系统,研究了该系统的非线性动力学扰动模型。利用双曲函数待定系数、扰动理论和方法,求得了对应模型的孤子波解并论述了对应物理量的特征。

利用近代数学物理的渐近理论,研究了一类流行性传染病传播非线性动力学系统.首先,提出了流行性传染病传播微分动力学模型.其次,引入一组泛函分析同伦映射,将动力学系统的解晨为由一个人工参数的幂级数.然后,逐次地求出该动力学系统的各次渐近解析解.最后,阐述了动力学模型解的意义.