权回归扰动模型的影响分析

针对线性加权回归模型，从统计诊断的角度分析了协方差阵扰动的影响度量和回归系数的估计效率，并给出了2种效率的下界。     

Adaptive output feedback stabilization for a class of nonlinear systems with inherent nonlinearities and uncertainties

This paper investigates the problem of adaptive stabilization by output feedback for a class of uncertain nonlinear systems. The distinguishing feature of such a class of systems is the presence of uncertain control coefficient and unmeasured states dependent growth with growth rate of polynomial‐of‐output multiplying an unknown constant. First, new high‐gain K‐filters with two dynamic gains are introduced, and an appropriate state observer is constructed based on the K‐filters. Then, motivated by the universal control idea, the backstepping scheme is successfully developed for the adaptive output feedback control design. By appropriate choice of the design parameters, the global stability of the closed‐loop system can be guaranteed. Finally, numerical simulations are provided to illustrate the correctness of the theoretical results. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of the angle of attack on the wind convection coefficient

In this study the effect of the positive angle of attack (angle between flat plate surface and incoming uniform flow) on the convective heat transfer coefficient was investigated numerically. In the case of inviscid flow, this effect was also presented analytically and was found to be in good agreement with the corresponding numerical results. From the obtained numerical data, an accurate correlation equation of Nusselt number was proposed by introducing the effect of the angle of attack in terms of a new factor A_f. The variation of the convective heat transfer coefficient as a function of the angle of attack was found not behaves in the same manner for both small and large values of Prandtl number at small angles of attack.     

萃取法测定混配配合物稳定常数的新方法

提出一种萃取法测定饱和配位数为2的混配配合物稳定常数的新方法.利用了有机相中混配配离子最大分布系数的性质,测定原理简单,且能得到满意的结果.     

一种流媒体实时水印嵌入与检测方法

研究了现有数字水印方案及算法,提出了基于I帧DCT系数的流媒体实时水印嵌入与检测方法,为数字媒体内容安全传输和有效监测提供了一种技术手段,并已将该方法用于互联网音视频监管方案中。     

Prediction method of critical power by film flow rate measurement and subchannel analysis

This paper presents a method that can estimate the critical power of boiling water reactors, BWRs, with regard to spacer geometry. The current experimental method for estimating the critical power for BWR design requires many trained experts and expensive facilities to conduct the experiments. In the present method, the liquid film flow rate of adiabatic gas‐liquid two‐phase flow and a subchannel analysis of the actual BWR flow condition are measured experimentally and analyzed. In the experiment, deposition enhancement coefficients of three spacer geometries—a ferrule, an egg‐crate, and a ferrule spacer with twisted tape (CYCLONE spacer)—were estimated by measuring the liquid film flow rate of air‐water two‐phase flow flowing up in a vertical square (4 × 4) rod bundle that simulated the rod bundle of a BWR. Using these coefficients, the critical powers for bundles using each type of spacer geometry were calculated in the subchannel analysis. This method was validated using previous critical power data in the actual BWR flow condition. The critical powers predicted by this method agreed well with those of the experimental data. The result confirmed the effectiveness of this experiment‐simulation combined method, as well as the advantage over current experimental methods in terms of human and facility costs. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(5): 309–323, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20069     

生态植生混凝土实验研究

针对同粒径同等粉煤灰掺入条件下,从水灰比、振捣方式以及外加剂3个因素上考虑,对生态植生混凝土的渗透系数、抗压强度以及孔隙率进行测定,分析其力学及物理性能,探讨生态植生混凝土制备效果,为生态植生混凝土的应用与推广提供实验依据和技术支持。     

The significance and use of the friction coefficient

The quantity known as the friction coefficient (or ‘coefficient of friction’) has long been used in science and engineering. It is easy to define, but not easy to understand on a fundamental level. Conceptually defined as the ratio of two forces acting, respectively, perpendicular and parallel to an interface between two bodies under relative motion or impending relative motion, this dimensionless quantity turns out to be convenient for depicting the relative ease with which materials slide over one another under particular circumstances. Despite the fact that both static and kinetic friction coefficients can be measured with little difficulty under laboratory conditions, the time- and condition-dependent characteristics of friction coefficients associated with both clean and lubricated surfaces have proven exceedingly difficult to predict a priori from first principles.The shaky nature of friction's fundamental underpinnings, has not prevented investigators from compiling lists of friction coefficients and publishing them for general use. Problems often arise, however, when engineers attempt to use tabulated friction coefficients to solve specific problems in mechanical design or failure analysis. The systems-dependence of frictional behavior is sometimes ignored, leading to misapplication of published data. This is particularly true for applications in nano-technology and others that differ from typical laboratory size scales. This paper will review the measurement and use of static and kinetic friction coefficients, discuss their usefulness, and describe the sources of frictional resistances in terms of shear localization.     

建筑工程量的自动计算

针对Excel软件计算工程数量中扣除门窗及洞口工作的繁重性，介绍了计算过程中只要输入门窗编号及数量就能自动扣除的方法，给出了该方法使用的工具，即公式与常用函数，以提高工程量的计算速度和准确精度。     

Do suspended sediments modulate the effects of octylphenol on rainbow trout?

A system was devised which allows particles to remain in suspension in a conventional 60 L aquarium without undue disturbance to resident fish. Using this system, juvenile rainbow trout were exposed for one week to 4-tert-octylphenol (OP, 10-1000 μg/L) with or without the presence of suspended sediments (10-20 mg/L of natural suspended sediments from the River Calder, UK). About 8% of the added OP partitioned to the solid phase. Vitellogenin levels were determined in the plasma of the exposed rainbow trout and showed a dose-dependent increase with regards to OP exposure concentration. Considerable variation in the vitellogenin response was observed between separate runs with the same OP concentration. There was no statistically significant (at P < 0.05) difference in plasma VTG levels between the OP treatments with or without suspended sediments. This suggests that the dissolved concentration is the key factor and natural suspended sediment neither protects against, nor exacerbates, the endocrine disrupting effect of OP on fish.