变化系数

The angular distribution of the scattering coefficient of the HH polarization is obtained by numerical implementation, the influence of the fractal dimension, the special fundamental frequency, the scale interval, the permittivity of substrate medium, the permittivity and the mean layer thickness of intermediate medium, the root mean square of rough surface, and the frequency of the incident wave on the bistaticscattering coefficient is discussed.

通过数值计算得到了HH极化下双站散射系数随散射角的变化曲线，讨论了分维、空间基频、标度区间、底层介质介电常数、中间介质介电常数和厚度、粗糙面高度起伏均方根及入射波频率对双站散射系数的影响，得到了平面波入射一维带限Weierstrass分形分层介质粗糙面散射系数的分形特征、基本特征、分区特征和随频率变化的特征。

The common method, that all strong-correlation terms of the model are eliminated, can bring the loss in the engineering application, so the new method is proposed that the identified model reserves some correlation. The augmented matrix A is constructed by the outputΔW and the matrix S. The"determinating order based on ratio of determinant"is brought out to screen the strong-correlation terms in the structure identification. The latent root estimation is improved in screening the eigenvalues and eigenvectors. Thus the estimation precision is improved greatly.The consistence check of guidance instrument error coefficients of flight test and ground test is the purpose of flight experiment. The causes of inconsistency of the two models are analyzed. The hypothesis test of linear regression model based on F statistics is proposed to check the consistence.Finally, the instability of error coefficients is probably caused by the change of the flight environments, therefore, the relation between the error coefficients and flight environment is analyzed. The approach is presented to identify SINS guidance instrument error models and compensate the error in the segmented sections corresponding to the change of vertical acceleration of aircraft.

在结构辨识中，常用的方法由于将模型中的强相关项全部剔除而给工程应用带来损失，因此，本文提出了新的有益思想，即在保留一定相关性的基础上进行辨识：将输出向量ΔW与环境函数矩阵S构成增广矩阵A，然后采用"比定阶行列式"来剔除相关向量的方法，这样既可以尽可能多地保留了对落点影响大的强相关参数，又可以对落点影响小的强相关参数给予剔除；在参数估计中，改进了特征根估计中特征根和特征向量的筛选方法，提出"近零"准则，从而大大提高了参数估计的精度；再者，鉴于天地模型"一致性"检验是飞行试验和SINS制导工具误差系数分离的主要目的，因此，本文又深入分析了造成天地模型不一致的原因，提出了采用基于F统计的线性回归模型假设检验方法来进行捷联制导工具误差模型的天地"一致性"检验；最后，鉴于飞行环境剧烈变化可能会对惯性仪表误差系数稳定性带来一定的影响，因此本文深入地分析了SINS制导工具误差系数与外界环境的关系，提出了基于过载变化大小的分段辨识和分段实时补偿的算法。

By making use of multi-points backward pressure of one dry gas well, this paper introduces how to confirm dynamic friction coefficient of downhole tubing at the exact moment through stable testing material, gives the productivity and the corresponding bottom hole pressure by using productivity equation, calculates wellhead pressure in combination with dynamic friction coefficient of tubing, establishes the correct wellhead outflow performance equation for this well, draws out wellhead outflow performance curve and discusses how wellhead outflow performance equation or wellhead outflow performance curve changes with the decrease of formation pressure or the change of wellhead outflow performance curve.

借助1口干气井的多点回压法试井资料，介绍了如何利用气井稳定试井资料，确定该气井此时此刻井下油管动态摩阻系数；利用产能方程给出产量和对应的井底压力，结合油管动态摩阻系数计算井口压力，建立该井准确的井口流出动态方程并编绘井口流出动态曲线；讨论了随着地层压力递减和井下油管动态摩阻系数变化规律，井口流出动态方程或井口流出动态曲线的变化规律。

Results show that the equivalent mass in normal direction depends on the modes of collision. In the case of reversed sliding and sticking, the coefficient of restitution varies as a result of the instantaneously changes of the equivalent mass during impacting process. The coefficient of restitution depends not only on the contact force, but also on the kinematical and dynamic parameters of the two rigid bodies. Moreover, a formula is proposed to calculate the coefficient of restitution.

指出法向等效质量依赖于碰撞状态，在反向滑动和停止滑动这两状态下的法向等效质量是变化的，因此导致其恢复系数是变化的，这样，恢复系数不仅与接触力有关，而且还与两刚体的运动和动力参数有关，同时给出各种碰撞状态下的恢复系数计算式。

Thermal conductivity is measured by the transient hot-wire method, which shows that the thermal conductivity increases with the increase of nanofluid particle volume fraction and temperature. The thermal conductivity of 0.3vol% SiO2-water nanofluid increases by 11.5% at 25℃, while it increases by 46.5% at 50℃ when compared with water at the same temperatures.

采用瞬态热线法测量纳米流体的导热系数，结果表明：纳米流体导热系数的变化与纳米颗粒体积分数和温度的变化成正比，其中25℃时体积分数为0.3%的SiO2-水纳米流体相对于水的导热系数提高11.5%，而在50℃时则提高46.5%。

On average, the SSC in winter is 2 times than that in summer; and the SSC in spring tide is 2.96 times than that in neap tide.(2) The correlation coefficient of the daily tidal range and SSC at a tide circle is 0.86, and it goes up to 0.96 and 0.93 with one day and two days lag of SSC. This reflects that there has a hysteresis of one or two days of SSC to the tidal range.

三年平均而言，冬季悬沙浓度为夏季的2.0倍，大潮悬沙浓度为小潮的2.8倍；(2)平均的大-小潮半月周期变化中日悬沙浓度与同日潮差之间的相关系数为0.86，(显著性水平0.01)，与提前1日潮差之间的相关系数为0.99(显著性水平0.01)，与提前2日潮差之间的相关系数为0.93(显著性水平0.01)，反映潮差变化对悬沙浓度的影响有1-2天的滞后效应；(3)芦潮港月均悬沙浓度与长江大通站的月均流量呈显著负相关，尤以流量滞后19天的相关性最好。

At the beginning, the coefficient of friction changed intervein.

在摩擦初始时，摩擦系数呈现交错变化，随时间的推移，摩擦系数出现分化，石墨化度高的试样摩擦系数较低，当石墨化度增加50%时，磨损率增加0.05%，磨损量变化不是很大。

The experimental results are as follows:(1) Without EAF the fouling resistance increase along with addition of time and change of the heat transfer coefficient is just contrary to the result. However, with EAF fouling resistance still enhances at the beginning of experiment and later, it gradually minishes after experiment has started for some time. Of course, the change of heat transfer coefficient still is contrary to the outcome. But when experiment lasts longer time, fouling resistance and heat transfer coefficient change in the same trend as the fore results at the beginning of the experiment. However, They all go to the tranquilization until the last.

实验结果表明：(1)没有经过电磁处理时，污垢热阻随着时间的增加而增加，换热系数随着时间的增加而减小；一旦经过电磁场的处理，污垢热阻开始时仍呈上升趋势，经过一段时间以后，便逐渐下降，换热系数的变化与此正好相反，即在实验开始时呈下降趋势，后来逐渐上升；当实验时间延长时，发现污垢热阻及换热系数在实验开始时的变化趋势与前面的实验结果基本相同，但到后来，二者的数值则分别均趋于稳定。

The effect of transgenx Bt cotton on non-target insects The kinds of the dominant species of pests in transgenic cotton field had obvious change, in which the H. armigera was no longer the main pest and the piercing-sucking pests such as Aphis gossypii, Tetranychus urticae, Thrips tabaci etc. rose the main pests. The kinds of the dominant species of predatory natural enemies seemed to be no variation, which was still Propylaea japonica Thunberg. Because of the effect of transgenic Bt cotton on H. armigera laevae-the development delay, the weight reduction, which affected the qualities of parasitic enemies, leading to the reduction of the weight of cocoon and the weight of adult, and the reduction of H.

转Bt基因棉对节肢动物群落整体结构及时序变化的影响 2001保铃棉与冀抗668的相似系数最高(0.8246)，冀抗668、保铃棉与常规防治的相似系数依次0.6459、0.5829，保铃棉和冀抗668与常规不防治的相似系数为0.5669、0.4485.2002 年与冀杭668的相似系数最高(0 。6887)，保铃棉和冀抗668与常规防治相似系数为0.4739、 0.3828，保铃棉和冀抗668与常规不防治的相似系数为0.3124、0.3999，此结果表明，两转Bt 基因棉田节肢动物群落的整体结构一致，相似性较大，与常规防治相比，相似系数有所降低，表明常规功治棉田中人为控制因素对节肢动物有一定影响；转Bt基因棉对节肢动物群落有一定影响，但并不显著。

The strongly negative correlation between winter sea-ice extent of Davis Strait and August rainfall of North China turns into bad correlation.

冬季戴维斯海峡海冰面积和北半球夏季、7月500Hpa位势高度场年际关系的年代际变化主要是相关系数分布型的变化：1974年前，相关系数分布型呈一个自新地岛开始经巴尔喀什湖到日本海的&-+-&型，该型和同期华北降水的反相关较好；1974年后，相关系数分布型变为呈自乌拉尔山开始经贝加尔湖到河套的&+-&型，该型和同期华北降水相关差。1974年前，冬季戴维斯海峡海冰面积和北半球8月500Hpa位势高度场的相关系数呈一个自乌拉尔山开始到鄂霍次克海以北分布的&+-+&型，该型和8月华北降水的反相关较好；1974年后，相关在欧亚大陆地区变差，没有明显的相关型，冬季戴维斯海峡海冰面积和8月华北降水关系变差。

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。