查询词典 Bessel

The paper simply introduced the basic principle of surface nuclear magnetic resonance and computed the numerical integral of nuclear magnetic resonance kernel function which contained double Bessel functions using the method of Gauss quadrature and continued fraction expansion, and then discussed influence of conductivity to nuclear magnetic resonance′s signal.

简要介绍了地面核磁共振找水的正演理论方法，采用高斯求积并结合连分式展开的方法对核磁共振核函数中包含双重贝塞尔函数的积分核进行了数值积分，进而计算出精度较高的核函数值，在此基础之上，讨论了导电性对地面核磁共振信号的影响。

Using the continued fraction method other than the traditional recurrence methods to generate the Bessel function, we built an accurate code for calculating the Mie scattering.

2利用Mie散射模式计算气溶胶散射相函数的展开式系数，直接提供逐次散射计算中所需要的立体角积分网格上的相函数，避免为获得相函数而进行内插。

Unstable Bessel optical resonator consisted of an axicon and a convex spherical mirror is studied.

研究了由圆锥透镜和凸面镜组成的非稳贝塞尔光学谐振腔。

In this thesis, the research on"the Nodal Green's Function Method For Cylindrical Geometry on Neumann Boundary Condition Based on Bessel Functions" is a pioneer work.

以上工作的完成，使该程序系统成为清华大学核研院堆芯物理设计和燃料管理的核心程序。

Since the multiple scattering should be considered, the scattering problem of many-cylinders is more complicated than single cylinder. By using scattering matrix method to solve the scattering problem of many-cylinders, first we have to express the incident fieldand scattered field by special function（for example, Bessel function and Hankel function）under cylindrical coordinate, then use the addition theorem of special function to get a linear system of equations to relate the incident field coefficients and scattered field coefficients. The incident and scattered field coefficients for every cylinder can be solved from the linear equations by matching electromagnetic boundary condition pointwisely.

单颗圆柱散射体的散射场解析解很早就被解出，而多个圆柱阵列的散射场问题因为涉及到入射光在圆柱与圆柱间的多重散射，故散射行为较单颗圆柱的散射复杂，因此圆柱阵列的多重散射问题需要利用加法定理来处理；散射矩阵法的主要精神即是先用圆柱座标下的特殊函数对平面波和圆柱散射体的内外域电磁场做无穷级数展开，再藉由特殊函数的加法定理将所有圆柱散射体的展开中心移到同一个展开中心，最后可以得到一组连结整个散射系统的入射电磁场系数及散射电磁场系数的线性方程组，将该组线性方程配合电磁场在散射体边界的连续条件，便可分别求出圆柱阵列中各个圆柱体的内部电磁场与外部散射场，再利用线性叠加原理即可求得整个圆柱系统的全域电磁场分布。

According to Bessel function and Fourier series theory, generation, magnitude and distribution of voltage harmonic generated by single-phase two-level SPWM inverter and three-phase SPWM inverter are analyzed and calculated particularity and concretely in allusion to inverter-motor system.

然后针对逆变器-电动机系统，利用贝塞尔函数和傅里叶级数理论，分别对单相二阶SPWM逆变器和三相SPWM逆变器的输出电压谐波的产生、大小和分布进行了细致而具体的分析和计算。

Firstly, the equation for stress intensity factors under static uniform pressure is used as the reference case, and then the weight function for a thick-walled cylinder containing a radial edge crack can be worked out. Secondly, the dynamic stresses in uncracked thick-walled cylinders are solved under internal impulsive pressure by using mode shape function method. The solution consists of a quasi-static solution satisfying inhomogeneous boundary conditions and a dynamic solution satisfying homogeneous boundary conditions, and the history and distribution of dynamic stresses in thick-walled cylinders are derived in terms of Fourier–Bessel series. Finally, the dynamic stress intensity factor equations for thick-walled cylinder containing a radial edge crack subjected to internal impulsive pressure are given by dynamic weight function method.

首先采用静态内压下的应力强度因子作为参考解，得到了带径向边裂纹厚壁圆筒的权函数；然后用振型函数方法推导无裂纹厚壁圆筒在冲击内压下的动应力响应，分析中将相应的弹性动力学方程解分为满足非齐次边界条件的准静态解和满足齐次边界条件的动态解的叠加，利用傅立叶-贝塞尔级数展开，推导出了厚壁圆筒内动应力的响应历程和分布规律；最后由动应力权函数方法导出带径向边裂纹厚壁筒在冲击内压下的动态应力强度因子计算公式。

All the most commonly used special functions are included: Bessel functions, Fresnel integrals, etc.

所有最常用的特殊功能包括：贝塞尔函数，菲涅耳积分等

In order to study the propagation of partially coherent modified Bessel-Gaussian beams passing through a paraxial ABCD optical system with hard-edge aperture,the approximate analytical propagation equation was derived with the hard-edged aperture function expanded into a finite sum of complex Gaussian functions.

为了对部分相干修正贝塞尔－高斯光束通过有硬边光阑近轴4BCD光学系统的传输进行研究，采用将硬边光阑窗口函数展开为有限个复高斯函数之和的方法，得到了近似的解析传输公式。

As an application example,numerical calculation was performed for partially coherent modified Bessel-Gaussian beams propagating in free space with hard-edge aperture,and the computation errors and application ranges of those analytical equations were discussed.

以部分相干修正贝塞尔－高斯光束在有光阑情况下自由空间的传输为例作了数值计算，对所得解析公式的计算误差和适用范围进行了讨论。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。