查询词典 external field

In studying the linear response of the dressed quark propagator in the presence of the variable external field, we derive a general expression for the vacuum susceptibility, based on the two-point external field formula in the Quantum Chromodynamical sum rule. The expressions we have derived for the calculation of vacuum susceptibility are model independent. Then we use the expressions to calculate the renormalised axial vector, vector and tensor vacuum susceptibilities.

接下来在研究夸克传播子在外场中的线性响应时，我们利用QCD求和规则两点外场公式推导出了一般的计算真空磁化率的公式（以变化的轴矢量外场为例），我们这里推导出的真空磁化率的计算公式是模型无关的。

In this book the emphasis is on the role of the Dirac equation in the relativistic quantum mechanics of spin-1.2 particles. We cover the range from the description of a single free particle to the external field problem in quantum electrodynamics.

本书着眼于Dirac方程在1/2自旋粒子的相对论量子力学的作用，覆盖了从单个自由粒子的相对论量子力学到量子电动力学的外加场问题。

In this thesis, we focus on the theory for the interaction of molecular dipole moment with external electric field and use the numerical simulation to investigate the rotational state-selection of polar molecules in a hexapole electric field and the laser-field role of alignment or orientation for molecules based on semi-classical treatment, the detail is the numerical calculation for a quantum mechanical treatment of molecules and their interaction with the external field and a classical electrodynamical treatment for static electric field.

本文研究是在描述分子偶极矩（永久偶极矩或诱导偶极矩）和外电场相互作用的基础上，我们建立了对分子态选择和角动量取向、准直研究的半经典理论框架（即分子体系状态、能量及与外场相互作用使用量子理论描述，分子的运动轨迹使用经典电动力学描述），并利用数值计算方法对静电场和随时间变化电场作用下分子的转动态选择、取向和准直过程进行了研究。

4 We show that the Dirac operator in an external field has the same essential spectrum as the free Dirac operator provided the potential vanishes at infinity.

在4.3.4节，我们证明了狄拉克算子在外场中有着对应着无穷远处时零势能极限的自由狄拉克算子的相同的本质谱。

The first excited state is very sensitive to the external field.

第一激发态对外加电场敏感，而其它激发态不敏感。

The plot of reduced magnetization versus the ratio of the external field and temperature is indicative of a strong zero-field splitting and magnetic anisotropy.

以还原磁化强度为纵坐标，外加磁场对温度的比值为横坐标，所得的图表明，该簇合物具有强的零场分裂和磁各向异性。

Furthermore, the improvement of distribution or retrieval by an intermediate external field will get limited due to the overloading of the networks.

而且适度的外场对分布或检索的改善又会因网络过载而受到限制。

Secondly, based on spectral representation theory and self-consistent mean field approximation, we study temperature effect on optical bistability of metal-dielectric granular composite under strong external field in the dilute limit by in MG model.

在谱表示和自洽平均场近似基础上，用Maxwell-Garnett 模型研究了在稀释极限下的金属-电介质颗粒复合体在强场作用下的双稳结构的温度效应。

Compared with what has been investigated, the effects of the parameters of the system and the properties of the external field on spontaneous emission are discussed in detail in this thesis.

本论文同以往的工作相比，更详细的讨论了系统参数，尤其是外场性质对自发辐射的影响。

Functions in a weak external field like the pion or electromagnetic field, which polarizes the otherwise-with-no-Lorentz-structure QCD vacuum, induces new condensates and affects the propagation of quarks and gluons in the vacuum.

外场的存在，将使原来没有 Lorentz 结构的 QCD 真空极化，诱导出一些新的凝聚量，另一方面外场的存在将改变夸克在真空中的传播行为，并且需要增加一些唯象参量。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐