近似连续

During the process of consecutive first-order reaction, the trend of the intermediate is largely determined by the ratio of the rate coefficient; therefore this case leads to an important method:steady-state approximation.

在连续反应中，速率系数的比值很大程度上决定了中间产物浓度的走向，并由此引出了一个重要的方法：稳态近似法。

The continuously varying of the refractive index is considered, and according to the property of holographic material, the small wavenumber approximation is utilized and the periodicity of the grating is used.

在矩阵建立过程中考虑了介质折射率是连续变化的，并且根据全息介质的特性采用小波数近似，同时充分利用了光栅结构的周期性特点。

Inverse function conversion was conducted for approximate analytical solution of semi infinitive sand column during dispersive test under the condition of one dimensional steady flow and injection of tracer with constant concentration.

文中将描述一维、稳定流场和连续注入定示踪剂浓度条件下的半无限砂柱弥散试验中示踪剂浓度随时空变化的近似解析解进行了反函数变化。

As same as the above-mentioned reason, because theconditions at the inside straight boundary of the binarycomposite material can not be easily satisfied, here, anelastic circular inclusion with large radius is used to replacethe upper half space of the binary composite material, so the〓mary binary composite mater ial problem can be changed〓the scattering problem of a circular elastic inclusion andto the scattering problem of a circular eastic inclusion and〓circular cavity in an infinite space to the steady incident〓wave.

与前面两个问题的理由一样，同样，由于问题中双质复合材料的内部直边界上的边界条件不易解析满足，为此，本文采用了一个半径很大的弹性实夹杂来代替问题中双质复合材料的上半空间部分，而将原来的双质复合材料问题转化成了无限大空间中一圆形弹性夹杂和一圆孔对稳态P波的共同散射问题，根据该问题的特点写出了弹性夹杂内外波场中波函数的一般形式解，利用该问题中夹杂和圆孔处的位移和应力的连续条件，并采用复数傅立叶级数展开技术将其化为一个仅包含问题波函数中未知系数的无穷线性代数方程组，在满足一定计算精度的前提下，通过有限项截断进行近似求解，进而讨论了双质复合材料中圆孔边界处的动应力集中系数随不同入射角、圆孔的不同位置、以及入射波的不同无量纲波数的变化和分布情况。

Based on Valley's quasi-cw approximation, the writing and erasing of gratings in materials exhibiting bulk photovoltaic effect on illumination with short light pulses is investigated.

利用G.C.Valley的准连续光近似模型，研究了短脉冲激光在光伏光折变材料LiNbO3晶体中写入和擦除光折变光栅的过程，给出了空间电荷场随时间变化的表达式。

At the same time, pattern recognition has been used for abstracting characteristics、predicting the life and evaluating the properties of engine. This research contributes toward global diagnosis for the diesel engine in eight ways.(1) Put forward"the Arithmetic of distinguish the period automatically using auto-correlation method";(2) Separate the waves of continuous knocks using WV distribution;(3) Propose"the logarithmic spectrum approximate method"to analysis the response of the knock between the steel and steel;(4) Discuss the relationship between the time-frequency distribution and timescale distribution in detail, and give the principle of classification;(5) Use the wavelet method to analysis the pressure signal of exhaust、suction;(6) Use the shape of vibration signal to analyse the working situation of cylinder;(7) Use the pattern recognition to select the good samples and abstract the effective characteristics;(8) Develop the model of total properties evaluation and life prediction.

本文在广泛的、深入研究的基础上，应用多种信号处理手段来分析处理数据，同时利用模式识别方法对故障的特征提取、寿命预测以及性能评价作了探讨，本文进行了以下几项工作：（1）提出了基于自相关自动周期识别算法的柴油机振动信号预处理策略；（2）提出了基于WVD分布的连续撞击响应信号的分离策略；（3）提出了基于对数谱拟合方法的钢—钢撞击响应求解模型；（4）提出了基于波形分析的非正常燃烧振动信号的诊断模型；（5）提出了基于小波细节信息的进气压力信号和曲轴箱压力信号的诊断模型；（6）提出了基于小波近似的喷油正时信号中燃烧位置的自动定位；（7）提出了基于统计模式识别方法的故障诊断知识的自学习与自组织策略；（8）提出了基于特征压缩思想的柴油机总体性能评价及寿命预测模型。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。