Therefore it is considered that the spontaneous emission of atom is caused by the fluctuation of dipole moment , not by the dipole moment oscillation of the atomic system 原子偶极矩的期待值总是零，但偶极矩的起伏恒等于一个不为零的常数，因此，原子的自发辐射是由偶极矩的涨落引起的，并非原子偶极矩振荡造成的结果。
While the pulse propagates in the fiber , it becomes asymmetrical and the asymmetrical sc spectrum is resulted eventually because the dispersion slope of the dispersion - decreasing fiber is not equal zero 由于色散渐减光纤的色散斜率不为零，因此脉冲在光纤中传输时产生不对称的情形，并最终产生不对称的光纤超连续谱。
Because of the van der waals repulsion between two substituents existed in chiral 1 , 2 - disubstitited ferrocene , the elevation angle of partial helix in the molecular structure is changed 由于手性1 , 2 -二取代二茂铁的两个取代基之间的范德华斥力，致使其分子结构中包含的部分螺旋改变了仰角，而这种改变使有关螺旋的旋光度代数和不为零，因而导致旋光性。
As the key part of synthetic jet technology , the synthetic jet actuator can work without fluid feeding and has momentum flux but no mass flux . since it only needs electricity when works , it can be controlled easily 合成射流激励器作为该技术的关键工作部件，具有无需流体输送，净质量流量为零，动量不为零的特点，而且合成射流激励器工作时只需要电能，易于实现电参数控制。
It is paid attention to that the longitudinal component of electric field of the coaxial tm01 mode can be strong , differing from the tem mode in the conventional coaxial waveguide . so the coaxial tm01 mode can have much strong interaction with the electron beam 值得注意的是,与普通同轴结构tem波不同,同轴慢波结构tm01模式的纵向电场不为零,这是同轴返波振荡器中的电子束能够与它有强相互作用的重要原因。
You may require that certain text fields not be zero - length , that a field be formatted as a phone number or other type of well - formed data , or that a string not contain any unsafe characters that could be used to compromise the security of a database 可能需要让某些文本字段的长度不为零，或者让字段的格式设置为电话号码或其他类型的格式良好的数据，或者让字符串不包含任何可以用来破坏数据库安全性的不安全字符。
In this paper we use pointwise modulus of smoothness ( f , t ) to study approximation direct theorem and equivalent theorem for some linear operators and quasi - interpolant operators ; using pointwise modulus we discuss the strong converse inequality on k - functional ; and using a modified weighted k - functional and weighted modulus of smoothness we study approximation with jacobi weight on operator with non - zero first order moments 本文利用点态光滑模_ ( ~ ) ~ ( 2r ) ( f ， t )来研究某些线性算子及逆中插式逼近正定理和等价定理；利用点态光滑模讨论其关于k -泛函的强逆不等式；同时利用一种改变的带权k -泛函和带权光滑模研究一阶矩不为零的算子的点态带jacobi权逼近。
When the accelerating time of frequency is equal to zero , this paper discusses the gain of inventer - induction motor under the vector controlled and non - vect or c ontrolled . at the same time , this paper discusses it while the time of slope is no t zero . the m othod of the slippery and difference is introduced in this papaer for designing the system contained inv - m 讨论了频率加速时间为零时，矢量控制和非矢量控制两种情况的通用变频器异步电动机的传递函数，同时也讨论了斜坡给定时间不为零的通用变频器异步电动机传递函数，介绍了滑差限定的方法，为设计含有inv - m的系统提高提供了理论依据
If an electron with k state is initially in one miniband , elastic scattering will make the difference of the probability band occupation tend to zero . if electrons initially are located at a single wannier state , elastic scattering will make the difference of the probability band occupation tend to a constant which does not equal zero . the stable distribution in k space is just the same as the average distribution when no scattering 发现弹性散射会破坏电子间的关联，使得初始处在某一微带上的态电子在两微带上的占有几率趋于一致；初始电子处在实空间的单个瓦尼尔态上时，最后在弹性散射的影响下两带占有几率差不为零，并且在上的稳定分布和没有散射时的平均分布相同。
This dissertation gives detailed study to this 4d solution , especially to the equivalent or induced 4d energy - momentum tensor of the solution . it is found that this 4d solution can be interpreted as to describe exterior fields of a spherically symmetric star immersed in a homogenous and isotropic cosmic background radiation 本文对4维解，尤其是对该4维解所对应的einstein场方程中的能量-动量张量源，进行了详细研究，发现它可以解释为一个温度不为零的球对称星体的外部解。
