查询词典 gradient of scalar field

In this paper the software using the method of integral equation to calculate 3D magnetic field and another two programs which use the finite column method to calculate 3D heat field with phase transition and 2D gas-flow field are completed. These programs provide such technique as the access to large quantity data and a simple but effective method to eliminate hidden lines of objects, which are necessary for the calculating of 3D field.

本文应用积分方程法，编制了三维磁场计算软件，应用有限容积法编制了考虑相变的温度场计算软件和气流场计算软件，软件中实现了大容量数据的存储，提出一种简便的消隐方法，这些功能对于三维场的计算不可缺少。

The order of content of antibiotics in the soil of different vegetable fields was vegetable field in hoggery＞non-social effects vegetable field＞common vegetable field＞green vegetable field.

3不同类型菜地土壤中抗生素的总含量高低顺序为：养猪场菜地＞无公害蔬菜基地＞普通蔬菜基地＞绿色蔬菜基地。

Numerical simulations show that the results are accordant with conservation of energy; electrical field or magnetic field of the ray refracted to the isotropic medium does not parallel to the electric field or the magnetic field of original incident ray; the direction of optical axis and the magnitude of incident angle have a great effect on the energy and the polarization direction of the refracted ray.

数值模拟表明，所得结果满足能量守恒；射入各向同性介质中光的电场与原入射光的电场不再平行；光轴的取向和入射角的大小对折射光的偏振方向和能量有重大影响。

The EM field of arbitrary point in an irregular loop can be considered as the sum of the EM field of many circle loops in the irregular loop at the point. Therefore the authors may obtain the EM field of the irregular loop as long as the authors work out the EM field of each of the circle loops.

不规则回线内任一点的电磁场可以看成是其内部多个圆形回线在该点的电磁场之和，因此，只要求出不规则回线内各个圆形回线在该点的电磁场，将它们叠加就可得出不规则回线在该点的电磁场。

In this paper, an iterative approach to potential field continuation from curved surface to plane is proposed. The continuation of potential field data from a curved surface to a plane can be viewed as an inverse problem of upward continuation of plane potential field data, getting a linear integral equation. Through viewing the potential field data on the curved surface as the data on the average elevation plane of the curved surface, then using the wavenumber domain generalized inverse algorithm to downward continue the data from the average elevation plane to a given plane, and a topography correction based on the change of curved surface relative to its average elevation is implemented to the downward continued data on the given plane, finally the downward continued data plane is upward continued to the curved surface.

本文提出一种位场数据曲化平的迭代方法，即通过把位场数据曲化平视为平面位场数据向上延拓的反问题，得到曲化平的线性积分方程，再把曲面上位场数据视为曲面平均高程面上的位场数据，利用向下延拓的波数域广义逆算法把平均高程面上的位场数据向下延拓到设定平面上，再根据曲面和其平均高程面的相对起伏对设定平面上的向下延拓数据进行起伏校正，最后再把所得平面上的位场数据向上延拓得到曲面上的位场数据，并进行迭代。

The first is the connection between the changing electric field and the magnetic field. It arose from Oersted's experiment on the deflection of a magnetic needle and led to the conclusion: a changing electric field is accompanied by a magnetic field.

第一个是变化着的电场跟磁场相结合，它是从奥斯特的关于磁针发生偏转的实验中形成的，并且它得出了这样的结论：变化着的电场总是由磁场伴随着的。

All the measurement results of magnetic field of optical klystron before and after shimming are given, including the distribution of field integral and phase error on axis, field integral and RMS phase error for different gaps and transverse distribution of field integral.

详述了合肥储存环的光学速调管辐射段磁场垫补的三种方式，测量了垫补前后不同间隙下积分场分布、位相误差及横向均匀度，各项指标都达到了要求。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

The behaviors of the driven field and radio field are studied in this paper and it can be seen that the forming of EIA or EIT and the whole probing properties are controlled by the Rabi frequencies of both driven field and radio field.

本文对新引进的驱动场的作用规律进行了重点研究，研究结果表明，当驱动场和射频场的Rabi频率满足不同关系时，系统呈现EIA或EIT两种不同特性，探测吸收曲线的整体轮廓也随之改变。

Electromagnetics course mainly including basic phenomena and laws of electro- magnetics, electrostatic field in vacuum, in conductor and in electric medium, electric energy, stabilized current, stabilized magnetic field and its basic laws, electric and magnetic fields caused by a moving chager in lower speed, the transform of electric and magnetic fields between different systems of coordinates, inductive laws, eddy field, self inductance, mutual inductance and transient, molecule current and magnetic substance, ferromagnet, boundary conditions, magnetic circuit theorem, energy of magnetic field and density of magnetic energy, displacement current, Maxwell's equation, electromagnetic wave, Poynting vector.

电磁学课程的主要内容包括：静电的基本现象和基本定律，真空中的静电场，导体和电介质中的静电场，电场的能量与电场能量密度，稳恒电流，稳恒电流磁场的基本定律，运动电荷的电磁场，不同参照系之间电磁场的变换，电磁感应定律，涡旋电场，互感，自感，暂态过程，分子电流与磁介质，铁磁体，边界条件，磁路定理，磁场的能量和磁能密度，位移电流， Maxwell 方程组，电磁波和玻印廷矢量等。

We got alerted a couple of times while we were down south that HETs were on the way to bring us back up north because things were going to go hot again, but it was just rumors.

南下的途中我们不只一次得到警告说重型装备运输车将拉着我们重新北上，因为局势正在变得重新紧张起来，但这只是谣传。

It's the one where they find the ghost in the salt mine.

这一集是演他们在盐矿找到鬼