数值函数

Level set method introduced by Osher and Sethian is a numerical method, which translates the problem of evolution of 2-D (3-D) close curve into the evolution of level set function in the space with higher dimension. Level set is an accurate and steady algorithm; it can treat with the change of topology naturally.

水平集方法是由Osher和Sethian提出的一种数值计算方法，它将二维的闭合曲线的演化问题转化为高维空间中水平集函数曲面演化的隐含方式来求解，具有拓扑结构可自然变化、计算精度高、算法稳定的特点。

This method is also available for other problems of unsteady flow around complicated bluff bodies at medium or high Reynolds numbers and the results are used as reference for wake control The phenomena of the sinusoidally oscillating flow past a circular cylinder are also studied.

本文应用有限差分方法求解涡量-流函数形式的N-S方程，数值模拟了园柱瞬时起动后流动分离、旋涡生成、脱落以及随时间推进涡街产生和长期非定常演化过程，包括对称涡的生成，二次涡形成的α结构及卡门涡街等。

The model predictions agree well with the available correlations obtained numerically and experimentally, they are expressed as a function of porosity with no empirical constant, and they are helpful for understanding the physical mechanism for tortuosity of flow paths in porous media.

本模型与实验数据和数值模拟结果均吻合很好，且迂曲度仅仅是孔隙率的函数，没有经验常数，因而有助于人们理解多孔介质中弯曲流线迂曲度的物理机理。

The result pointed out that the vertical distribution of foliage for each species was different,however,generally speaking,the foliage in upper crown (0.3CL) for broad-leaved species in natural secondary forest took a small percentage,about 10%;in middle or middle lower of the crown(0.4CL to 0.8CL) the branches here took the majority percentage of whole foliage,almost 60%to 75%;but in lower crown(0.8CL),there was about 10%of whole foliage.(5)The interspecies competition of trees in secondary forest was expressed by Hegyi competitioin index,and the active competitor was calculated by the competition zone radius and the tree position,DBH,and distance in the zone,it was not all competitors in tranditional calculation.The study introduced crown area overlap index to describe the crown competition between subject tree and its competitors,furthermore,the crown area was classified into 5 levels with a method of equal crown projection area,therefor,the resulting crown area overlap index showed more realities of existing stand conditons.(6)Based on the theoretics of multiply divide,the spatial strcture optimizing model of secondary forest stand selective thinning was developed by diversity mingling,aggregation index,competition index and crown area overlap index,also designed 10 constraint conditions which were related to forestry meanings,the objective function was solved by the implicit enumeration method with LINGO 9.0,using 0-1 integer programming.

并且得出，每个树种在树冠内相对高度上的叶量的垂直分布是不同的，天然次生林阔叶树种的叶量在树冠的上部(0.3CL以下)所占比例很小，约占10%左右；在树冠的中部以及中下部(0.4CL～0.8CL)，叶量所占比例最大，几乎集中了整个树冠60%～75%的叶量；而在树冠的下部(0.8CL以下)，几乎占很少的叶量，大约10%左右。5、采用Hegyi竞争指数来表现次生林内林木的竞争关系，并且根据竞争圈的大小和林木在竞争圈内的分布位置、大小与距离来计算有效的竞争木，并不是传统意义上的全部竞争木；本研究提出用树冠叠加指数来表示林木与周围树木的树冠竞争情况，并采用等树冠投影面积法把树冠分为5级，这样计算的树冠叠加指数更加与现实林分相符。6、本研究基于乘除法的思想，用多样性混交度、聚集指数、竞争指数和树冠叠加指数构建了天然次生林择伐空间优化模型，设计了10个与林学意义相一致的约束条件，并采用0-1整数规划的思路，在LINGO9.0软件中使用了隐枚举法对目标函数求得最优解。7、以M702标准地为应用实例，具体计算出了每株采伐木，经过择伐后，目标函数值按模型设计的要求发生了极大的改变，增加了5倍多，说明了最后这个解的优良性，满足了设计的要求。

In more detail, the article adduces credit card analysis and credit management system .In credit card analysis, use K means algorithm,one of the method in clustering algorithm, to find the minimal partition of DSS.

在信用卡信用评分系统中，运用基于划分的聚类方法K means算法，试图找出使DSS函数值最小的划分，该算法的准则函数与信用评分评级的&均方差&准则相吻合。

The subject function values used nine indexes in tomato of high temperature stress including the rate of fruit setting, the relative output, the index of rolling leaves, the stabilization of membrane, the relative geminating of pollens, the contents of dissociating proline and the content of soluble sugar.

通过对高温下番茄的坐果率、相对产量、卷叶指数、相对生长量、膜稳定性、相对花粉萌发率、热害指数，以及游离脯氨酸和可溶性糖含量等9项指标的测定，采用隶属函数数值法，综合比较鉴定了耐高温能力不同的6个番茄品系。

In the computation Van Leers scheme is used to discretize the inviscid flux terms and a new Limiter function is constructed to realize TVD character.

数值方法中选用Van Leer 分裂格式离散无粘通量项，并构造了一种限制器函数以保证TVD性质。

Of being able to convert a number given in string representation to an actual float value, obsoleting the use of the atof function of the string module.

从 Python 1.5 开始， float 增加了把字符串表示的数值转换为浮点数的功能，没必要使用 string 模块中的 atof 函数。

Regarding to the Mechanical wave on Physics teaching, the traditional method usually fail to offer a direct and clear description and demonstration on the effectiveness of Mechanical wave, for this reason the MathCAD software has been adopted, with the various functions the MathCAD software offers, such as calculation, function chart drawing and cartoon designing, men can describe and demonstrate exactly how the Mechanical wave transmits, intervenes and superposes, and define and research the Doppler effect.

物理学在处理机械波的教学过程中，传统方法读其现象的描绘和演示不直观也不方便，现利用MathCAD提供的强大数值计算、函数图像创建和快速灵活的动画设计功能对机械波的传播、干涉和迭加进行了精确描述和动画演示，并对阻尼

An almond-shaped mass of gray matter in the anterior portion of the temporal lobe.

按等间距或任意间距的独立变量值获取一函数的数值。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。