展开系数

The electronic structures and the non-linear optical properties of bis schiff base and their derivatives have been studied using FF/HF method.The effects of electron donor/acceptor on nonlinear optical property were examined at the molecular level.As a result,the NLO coefficients of the substituted compounds are all larger than the unsubstituted compound.Among them, the β value of compound 4 is the largest one.

自1961年激光发现以来，非线性光学和非线性光学材料迅速发展起来[1～4]，随着光通讯、光电子学和光信息处理等在实际中的应用，对非线性光学材料的理论与实验研究进一步展开，寻找和设计具有较大非线性光学系数，超快光学响应，较低的光学损伤阈值，良好的化学稳定性和热稳定性的非线性光学材料成为这一领域的主题[5～12]。

Stability analysis of nonlinear magnetic suspension, the magnetic suspension system model was found based on electromagnet dynamics and voltage balance of the electromagnet coil; The feedback of position and velocity and current are used as the control variable; After the control rule was applied to the electromagnetic system, the louts criterion was used to get the range of the control parameter in which the system was steady-going.

非线性磁悬浮系统的稳定性分析，通过电磁铁动力学和电磁线圈的电压平衡方程，建立磁悬浮系统基本模型。求出系统奇点后，通过系统线性展开求出系统矩阵。用PD控制外加电流反馈量，将控制规律带入系统模型方程组求出矩阵的特征方程，由劳斯判据得知非线性系统稳定的位置反馈系数及取值范围。

We make a rather thorough review of the QCD sum rule approach, which includes the correlation functions and the spectral representations, OPE, Borel transformation, the fixed point gauge, condensates and their empirical values, Borel stability, the dispersion relation and the commonly used

我们对于 QCD 求和规则作了比较全面的评述，包括：关联函数与谱表示；算符乘积展开；Borel变换和固定点规范；凝聚量及其经验值；Borel 稳定性；色散关系和谱密度的常用模型；Wilson 系数的计算；外场方法等。

Then the remaining formidable challenge is to reliably evaluate the complicated hadronic matrix elements.

考虑QCD修正的效应，我们介绍了算符乘积展开如何将短程贡献干净的分离到Wilson系数中。

The scheme is based on non-mean quantisation parameters with invariant features,it utilises the concept of the 2-nd generation digital watermarking and uses the technique of quantisation watermarking.

针对商品包装图像在水印检测过程中图像会发生变形的问题展开研究，提出一种基于非均值量化系数特征不变的盲数字水印方案。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。