查询词典 calculus of finite difference

Finite Difference Time Domain method is adopted to evaluate the relationship between the off-axis angle of the beam and the temperature difference.

由时域有限差分方法得到光束偏转角度与温度差之间的关系。

The finite difference time-domain method is stable and easy to be used, but due to the fact that it approximates the space derivatives in Maxwells curlequations by central difference, FDTD usually requires more than 20 grids perwavelength to achieve acceptable accuracy. As a contrast, pseudospectraltime-domain method approximates the space derivatives by pseudospectralmethod, which guarantees the accuracy, theoretically requiting only 2 grids perwavelength.

传统的电磁场数值算法——时域有限差分法稳定而易于实现，但由于FDTD采用中心差分近似Maxwell旋度方程的微分，每个波长上需要取的网格数通常较多，而时域伪谱法采用伪谱法求微分，理论上每个波长只需要取两个网格便可以达到较高的精度。

By discussing the position hypothesis of fractional-dimension derivative about general function and the formula form the hypothesis of fractional-dimension derivative about power function, the concrete equation formulas of fractional-dimension derivative, differential and integral are described distinctly further, and the difference between the fractional-dimension derivative and the fractional-order derivative are given too. Subsequently, the concrete forms of measure calculation equations of self-similar fractal obtaining by based on the definition of form in fractional-dimension calculus about general fractal measure are discussed again, and the differences with Hausdorff measure method or the covering method at present are given. By applying the measure calculation equations, the measure of self-similar fractals which include middle-third Cantor set, Koch curve, Sierpinski gasket and orthogonal cross star are calculated and analyzed.

通过讨论一般函数的分维导数的位置假设及幂函数的分维导数的形式假设，进一步明晰了幂函数的分维导数、分维微分及分维积分的具体方程形式，给出分维导数与分数阶导数的区别，随后讨论了基于一般分形测度的分维微积分形式定义导出的自相似分形的测度计算方程具体形式，给出了其与目前 Hausdorff 测度方法的区别，并对包括三分 Cantor 集合、 Koch 曲线、 Sierpinski 垫片及正交十字星形等自相似分形在内的测度进行了计算分析。

In conclusion, the results of multilevel model analysis showed that the GERD score of resident in Wuhan was relatively higher and had significant difference with that in Guangzhou, however, that in Shanghai, Beijing and Xi\'an had no significant difference compared with that in Guangzhou. That is to say, the prevalence of GERD in Wuhan was relatively higher compared with the other four survey sites; the residents'health status more worse, the GERD score more higher, and the influence of health status on GERD score was also effected by the region difference between Wuhan and Guangzhou; residents lived in rural region with lower education level, worse spirit status were more likely to suffer from GERD; Moreover, those residents who had family history of GI tumors or other GI diseases, some anamneses (such as dyspepsia, gastritis, rheumatic arthritis), and some diseases (such as irritable bowel syndrome and aerophagia) were also more likely to report GERD. However, no significant association was found between GERD and some other factors in this survey, such as sex, age, etc.

总之，多水平模型分析结果显示，与广州相比，上海、北京和西安居民的GERD总评分没有明显的差异，而武汉居民的GERD总评分则相对较高，即表示武汉的GERD发病率在5个调查城市中相对较高；居民的总体健康状况越差，其GERD总评分越高，且其对GERD总评分的影响受到武汉与广州之间地域差异的影响；农村居民、文化程度越低、精神状况越差者更容易患GERD；另外，那些有胃肠道疾病或肿瘤家族史，既往患有胃炎、消化不良、风湿性关节炎，现患有肠易激综合征、吞气症的人，患GERD的可能性更大，而性别、年龄等因素，本研究未发现其与GERD有显著的关系。

The scattering properties of particles with different shape parameters are simulated respectively in the modes of reflection and refraction. Both in the modes of reflection and refraction, the phase difference of non-spherical particle's PDA signal is the unbiased estimate of the corresponding phase difference of ideal spherical particle, and the standard deviation of angle roughness scale on particle surface impacts little on the distribution of phase difference.

本文通过物理光学的方法分析了非理想球形粒子的散射特性，利用物理光学中的稳相点理论，导出了非理想球形粒子散射光的相位表达形式，分析了非理想球形粒子的形状对PDA信号相位及相位差的影响，建立了非理想球形粒子的尺寸分布与PDA信号相位差分布之间的关系。

To against an afterload of 1.96kPa(200mmH_2O), measure two groups of direct flow and antidromic flow, both begin with the pressure difference of 0mmH_2O, add more 20 mmH_2O every time ,measure three tines at each pressure difference, get the average value at each pressure difference.

测试分为顺向和逆向两组，在克服后负荷压强为1.96kPa(200mmH_2O)情况下，分别从0mmH_2O压力差开始，每隔20mmH_2O递增，测量通过静脉外间接人造瓣膜的生理盐水流量，每个压力差值测量3次，取平均值。

The structure of the execution organizations: Three kinds of differences were presented, including natural difference, functional difference between central and local organizations, and difference in division of decision-making.

一、在执行组织结构方面：呈现机关属性的先天差异、中央与地方的功能差异，以及事权划分的纠葛等三项分殊性。

In chapter 5, we study necessary conditions for difference sets and we obtain the following: we proved that there are no nontrivial difference sets in dihedral group of order 4p〓, where p is a prime, d is a positive integer; we give a necessary condition for Hadamard difference sets in some group of order 4p〓, and completely solve a general case left in Dr.

在第五章中，我们研究了差集存在的必要条件。

This paper is an investigation of the differences between monosyllabic and disyllabic time adverb as a synonymy which display in three aspects: the difference of syllable of the modifying object,the difference of pragmatic rank and the difference of grammatical function.

同义的单音节时间副词和双音节时间副词之间，存在三个方面的差异：修饰对象的音节差异、语用移位的差异以及语法功能的差异。

And the heat transmission model is computed with FEM. Then the paper analyzed rules of difference in temperature. Different in temperature is divided into transverse temperature difference and lengthways difference, and corresponding formulas are respectively presented.

并在此基础上，进行了导热问题的有限元分析，得到了温差分布规律，将计算温差分解为横向温差和纵向温差几，并建立了相应的温差计算公式。

You can snipe the second and third union leaders from this position.

您可以鹬第二和第三工会领袖从这一立场出发。

Aiming at the currently shortage of XML streams quality detecting, this paper proposes a new forecasting method of XML streams quality by least squares support vector machines, which is used the method of XML keys' vector matrix as windows, and vector product wavelet transform to multilevel decompose and refactor the XML streams series, that can fulfill real-time checking demand of XML quality, and ensure constraint, consist- ency and integrality. For even more adapting net load, it proposes a control strategy by weight and adaptive adjustment to ensure XML streams quality.

针对当前XML数据流质量检测存在的不足，提出构建XML键的矢量矩阵作为窗口，利用矢量积小波变换多级分解与重构XML数据流，再结合最小二乘支持向量机对XML数据流质量进行预测的一种方法，满足XML数据流质量重构时实时检测的要求，保证XML数据的约束性、一致性与完整性；为了更好的适应网络负载，采取加权与自适应窗口调整等调度策略充分保证XML数据流的质量检测。