弱激光驻波场上的无反射势阱

研究弱激光驻波场中的无反射势阱。利用直接微扰法,导出该系统非齐次Ｓｃｈｒｏｄｉｎｇｅｒ方程的积分形式的精确解。分析和数值研究发现,该解满足波函数有界的条件,但不能表示成初等函数的有限形式,并因此具有数值不可算性。     

Hamming预测-校正法迭代形式的改进

对Hamming预测-校正法的迭代形式进行改进,研究一阶常微分方程初值问题的数值解．并将Hamming预测-校正法的迭代形式与改进后的迭代形式在数值实验中进行了比较,证明了改进后的迭代形式与原来的相比,有更精确的数值解．     

一类复蒙日-安培方程Dirichlet问题数值解探讨(二)

蒙日-安培方程是高度非线性的偏微分方程,因此它的数值解非常困难.本文对第二类Cartan-Hartogs域上的复蒙日-安培方程Dirichlet问题数值解进行了探讨.首先,把该问题化为一个二阶非线性常微分方程的两点边值问题的数值解.其次,在一些特殊的情况下,得到了该方程Dirichlet问题解的显表达式,它可以用来检验该问题的数值解.     

利用指数函数法求Kudryashov-Sinelshchikov方程的精确行波解

Kudryashov-Sinelshchikov(K-S)方程具有重要的物理背景和研究意义,很多学者对其精确解进行了研究,在=-3和=-4时得到了各种形式的精确行波解.本文利用指数函数法对该方程的精确行波解进行了研究,获得了该方程在任意参数条件下具有一般形式的精确行波解,包括孤立波解和周期波解,将原有的结果进行了有效的推广.     

一类交通流模型研究

针对一类动态交通分配中的输出流模型,在一定的条件下,研究该模型的解,并利用数学软件Mathematica7给出初始条件下的数值解,最后结合特定路段的交通流数据进行数值仿真并进行比较.     

新冠肺炎传染病问题模型的建立及算法分析研究

采用数学建模思想构建新冠肺炎传染病动力学SIR模型,该模型对应的微分方程组不易求得解析解.因而,使用三类不同的Runge-Kutta方法数值求解该模型.最后,通过数值算例检验三种不同数值解的有效性,包括误差估计以及数值仿真等.     

带Poisson跳的随机时滞神经网络模型的数值解

本文对带Poisson跳的随机时滞神经网络模型的数值解进行了研究.通常情况下,大多数随机时滞神经网络模型没有解析解,因而数值逼近方法是研究神经网络模型解的有效工具.根据Euler数值方法,利用鞅不等式和Ito赞公式讨论了一类带Poisson跳的随机时滞神经网络模型的数值解.给出了在均方意义下数值解收敛到解析解的充分条件,并通过一个数值算例对本文所给的数值方法进行了验证.     

常微分方程数值解法的若干求解格式

对于大部分常微分方程,我们只能求出其近似解,而不能给出其精确解。另外,有些初值问题虽然有初等解,但由于形式太复杂不便于应用,因此,研究其数值解法,以便快速、便捷地求得数值解有其非常重大的意义。本文对常微分方程初值问题现有的数值解法进行综合研究,如:法、方法以及方法等,探讨一些类似的方法。     

一类参数识别问题的有限体积元计算

针对一个具有附加条件的抛物型偏微分方程的参数识别问题,提出了使用有限体积元法求数值解的方法,给出了未知函数和控制参数的数值解格,通过具体数例的数值解与精确解对比,表明该格式计算结果良好.     

随机Cahn-Hilliard方程的有限差分法

对随机Cahn-Hilliard方程建立六点Crank-Nicolson差分格式来求其数值解,以数值解来逼近方程的真解.最后,讨论了该格式的稳定性与收敛性.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.