查询词典 Fermi-Dirac statistics

To getrid of these shortcomings DMs are presented in quantum theorywhere the movement of individual electron is determined byquantum mechanics and the system of electrons obeys Fermi-Dirac statistics,in consequence they can find wider appli-cations than classical DMs.

这里个别电子的运动由量子力学刻画，多电子系遵循Fermi-Dirac统计规律，故它们比前三种经典公式普适性更强。

Statistics analysis is becoming more arduous and important as in now economy age statistics information affects the policy-making by the manager of enterprise. At present, there exists some problems in statistics analysis that it's hard to touch and reveal the true facts to analyse, so we can only judge the case as it stands. Therefore, to change the matter, statistics members have to collect a vast amount of data, master basic statistics theory?methods and certain academic knowledge proficiently, clear som...

新经济时代统计信息影响企业管理层决策成败，统计分析的任务更趋繁重，作用更显重要；现阶段统计分析存在着一些问题，统计难以接触、揭示真实情况，统计分析也只能是就数论数；要改变这种情况，统计人员必须大量收集资料，熟练掌握统计基本理论、方法及一定的专业知识，明了党和国家有关方针政策，有效发挥统计分析作用，开展专题分析，不断创新，开辟新视角、新思路，采用科学方法，运用现代技术，做好统计分析，提高统计质量。

Since a proposed application of Dirac structures is to the reduction of some mechanical systems, the reduction of Dirac structures is considered in detail in this paper, without using the existence of momentum mappings or the introducing of the notion of admissible function, etc..

因为引入Dirac结构的—个基本目的即应用于一些力学系统的约化，本文详细地讨论了Dirac结构的约化问题，包括其在Poisson流形以及Jacobi流形等的约化中的重要应用，重点利用了Dirac结构的特征对以及对偶特征对的工具，从而避开了讨论矩映射的存在性以及容许函数等一些复杂概念的介入。

Dirac's most accomplished works are two short papers in 1928 where he brought to the world the Dirac Equation.

狄拉克最了不得的工作是1928年发表的两篇短文，写下了狄拉克方程

The main advantages of using the Dirac equation in a description of electrons are the following:(1) The Dirac equation is compatible with the theory of relativity (2) it describes the spin of the electron and its magnetic moment in a completely natural way.

在电子的描述中用Dirac方程描述主要优势有：（1）Diarc方程同相对论理论是一致的；（2）它很自然地描写了电子自旋和自旋磁矩。

The MRI technology in use in hospitals today—one of many technologies given birth by the Dirac Equation—would not have been possible but for the new concept brought forth by Dirac.

没有狄拉克引进的观念就不会有今天医院里通用的核磁共振成像技术，不过此项技术实在只是狄拉克方程的一项极小的应用。

In 1976, S. Chandrasekhar solved the decoupling problem of the Dirac equation with non-zero rest mass in a Kerr background, thus provided the possibility of attacking the problem of the Hawking evaporation of Dirac particles.

在Kerr背景时空中求解Dirac方程是一个长期没有解决的问题。1976年Chandrasekhar成功地找到了Kerr背景时空中静止质量不为零的Dirac方程的退耦和分离变量的量子方程。

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。

Based on them, we calculated precisely some enegy levels of P-wave and D-wave of a helium atom, presented and proved the general interdimensional degeneracies for a quantum N-body system, derived the general spherical spinor functions and the exact solution to the Dirac equation for the hydrogen atom, and proved uniformly the Levinson theorem for the Dirac equation in D-dimensions.

在此基础上，我们精确计算了氦原子P波和D波若干较低能级，建立和证明了量子N体系统不同维数状态间最普遍的简并，推导出任意 D 维空间广义球旋函数和Dirac方程氢原子的精确解，统一地提出和证明了任意 D维空间Dirac方程Levinson定理的一般形式。

We introduce the notion of characteristic pairs and give the definition of dual characteristic pairs of Dirac structures on Lie bialgebroids. Using the dual characteristic pairs, we give the if and only if conditions for which a maximally isotropic subbundle of the double of a Lie bialgebroid is a Dirac structure.

本文在李双代数胚上，引入了Dirac结构的特征对并给出对偶特征对的概念，利用对偶特征对，给出李双代数胚double的极大迷向子丛是Dirac结构的充要条件；其次，分别利用特征对与对偶特征对，将可约Dirac结构分为第一类可约与第二类可约，在此基础上，建立Poisson流形的两类对应约化定理。

Cable dampener cannot be rolled up but must be hung over the cable.

缆帆不能被卷起，必须保证处于展开状态

"This skylark is a present from my master," he says.

"这只云雀是我主人献上的礼物。"他说。