系数

X-ray radiography, X-ray radioscopy and X-ray computed tomography were performed to the C preforms and C/SiC composites made by chemical vapor infiltration method. Elementary research of the simulation of X-ray nondestructive testing of C preforms and C/SiC composites was conducted. The main contents and conclusions are summarized as follows:(1) The equivalent absorption coefficients of graphite and SiC to Al (KAl/sic, KAI/C) were measured. It was found that in 35-45KV, KAl/sic=1.1~1.2 and KAl/c=0.08~0.12. That means X-ray radiography was much less sensitive to fiber defects than to SiC matrix. It was suggested that Al Image Quality Indicator would be used to evaluate the quality of X-ray radiographs of C/SiC.

本文选择X射线照相、X射线实时成像和X射线CT等三种方法对C纤维预制体及C／SiC复合材料进行了检测和研究，并对C／SiC复合材料X射线检测的计算机模拟做了初步的探索，主要研究内容和结果如下：(1)测定了C和SiC的X射线照相等效系数，在35～45KV的条件下，Al对SiC的等效系数K_为1.1～1.2，Al对C的等效系数K_为0.08～0.12，所以X照相射线检测C／SiC对C纤维缺陷不敏感，而对SiC基体缺陷敏感。

The elements of optical waveguide strain-stress measurement and fiber bragg grating strain-stress measurement system based on wavelength division multiplexing and spatial division multiplexing are emphatically discussed; the displacement regularity of stress field induced by roadway group excavating and short wall mining process is analyzed in detail; the concept of roadway "equivalent radius","correcting coefficient of coal and rock mass mechanical parameters",and "mining affecting coefficient" is put forward; the calculation method of "equivalent radius", the method of inversion of "correcting coefficient of coal and rock mass mechanical parameters", and the "mining affecting coefficient" determination method with the field measurement results and so on are provided.

重点研究了光波导应力应变测量原理，以及基于波分复用和空分复用技术基础上的布拉格光纤光栅应力应变测量体系；详细分析了近距离巷道群开掘工作和短壁体系回采工作诱发的应力场的重新分布规律；提出了巷道"当量半径"、"煤岩体力学参数修正系数"、"采动影响系数"等概念；给出了"当量半径"的计算方法、"煤岩体力学参数修正系数"的反分析求算方法、以及通过现

According to the first and second references, a sufficiency and necessity condition on rational root of integral coefficients polynomial is put forward and a reduced method of testing the rational root is also shown in this paper.

摘要给出了整系数多项式有理根的一个必要条件，从而得到整系数多项式有理根检验的一个简化方法，达到了简化整系数多项式有理根检验的目的。

Taking the active network as a research task, the input accessibility, the Coates graph of matrix and graph transmission etc are used to analyze the relation between reducibility of the coefficient matrix of the state equation and the electric separability of the network or the electric accessibility of the network for the first time, acquiring sufficient and necessary conditions that coefficient matrix of the state equation is reducible. Network Graph Theory, Matrix Theory and System Theory over F etc are used to derive the structural controllability criterion of the passive network over F for the first time. Then according to these theoretic results, the structural controllability problems of the active network over F are studied, acquiring several structural controllability conclusions of the active network.

率先将状态方程的输入可达、矩阵的Coates图、流图传输系数等概念和方法引入到对F上有源电网络的研究，研究了网络状态方程的系数矩阵的可约性与网络电气可断性或电气可达之间的关系，研究了F上有源电网络的能控性问题，获得了状态方程的系数矩阵可约的充分必要条件、F上有源电网络系统的结构能控性判据等新的结论。

For practical use, the root-mean-square of response is expressed as the product of basic wind load and an equivalent factor, which is defined as dynamic-wind-effect-coefficient.

为实际应用方便，将结构风振响应的标准偏差直接描述为基本风荷载与等效系数的乘积，该等效系数定义为"动力风效应系数"。

In China, the typical equipements to test the friction coefficient of highway pavement are SCRIM and Portable Friction Tester.

前言目前国内测定路面摩擦系数的仪器主要有横向力系数测试车和摆式摩擦系数测试仪。

Based on this equation, the effect of pressure, temperature on liquid diffusion coefficients was dis〓sed, then the mutual diffusion coefficients at infinite dilution of 35 binary systems and self-diffusion coefficients of 12 pure substances under high pressure have been calculated.

根据该方程讨论了温度、压力对液体扩散系数的影响，并计算了高压下35个二元物系的无限稀释扩散系数与12个纯物质的自扩散系数。

The impact of iron core conductance is reduced to the air gap; the impact of harmonic and slot coefficient on machines winding coefficient, self-inductance and mutual inductance is fully considered.

把铁芯磁阻的影响归算到气隙中，充分考虑了槽口系数以及谐波对电机的绕组系数、定转子绕组的自感、互感系数等参数的影响。

It is named shift operator FDTD method. The high accuracy and efficiency of this method is confirmed by computing the reflection coefficients of electromagnetic waves by a collisional plasma slab. The reflection coefficients between plasma and the atmosphere or vacuum can be calculated by using the SO-FDTD method.The result is that the reflection coefficie...

应用该方法计算了冷等离子体平板对电磁波的反射系数，通过与解析结果的比较，验证了该算法的高效性和高精度，同时，应用SO_FDTD方法，计算了等离子体层对垂直入射电磁波的反射系数，结果表明等离子体厚度、电子密度、电子密度的分布形式和入射波频率是影响反射系数的重要因素。

Assuming the independence (or the weak-correlation) between the reflectivity and wavelet, the optimal estimation equations for the wavelet and reflectivity were derived respectively. Furthermore, pre-conditional conjugate gradient algorithm iteration inversion was applied to realize the simultaneous estimation of reflectivity and wavelet.

基于反射系数与子波相互独立的假设，分别构建了反射系数和子波最优估计方程，并采用预条件共轭梯度法迭代反演实现反射系数和子波的同时估计。

Shop assistant: Please check at the door.

店员：请您到门口柜台交费。

In the end, transportation of PAHs in the environmental matrix was preliminarily investigated and discussed according to PAHs data of soils and sediments from a certain region in Shanghai. The result indicated that there are two or more pathways on PAHs transportation in the environmental matrix.

最后，对上海特定地区内PAHs在环境介质中的迁移径途进行了分析讨论，结果表明上海市土壤和沉积物等环境介质中PAHs的迁移存在多种途径。