裂隙岩体边坡稳定性的渗流与应力耦合分析

用裂隙岩体渗流与应力耦合分析的四自由度全耦合法对岩质边坡进行耦合分析,通过强度折减有限元法求解岩体边坡的稳定安全系数。四自由度全耦合法建立了同时以渗流水压和位移为未知量的耦合方程组,使得渗流场与应力场的求解能够一次性完成,与两场交叉迭代分析方法相比达到了彻底的完全耦合。通过强度折减,整个系统达到不稳定状态,有限元计算将不收敛,此时的折减系数就是安全系数。算例表明由此求得的边坡稳定安全系数和滑动面都与传统方法十分接近。     

直接还原在当代冶金变革中的发展

简述了当代的直接还原现状与方法，论述了直接还原是发展短流程的重要基础，直接还原也是熔融还原法的重要组成，同时分析了发展直接还原与熔融还原是当代世界冶金变革中的重要方向之一，也是中国面向２１世纪的重大任务。     

Inhibiting and deactivating effects of water on the selective catalytic reduction of nitric oxide with ammonia over MnOx/Al2O3

The effect of water on the selective catalytic reduction (SCR) of nitric oxide with ammonia over alumina supported with 2–15 wt.-% manganese oxide was investigated in the temperature range 385–600 K, with the emphasis on the low side of this temperature window. Studies on the effect of 1–5 vol.-% water vapour on the SCR reaction rate and selectivity were combined with TPD experiments to reveal the influence of water on the adsorption of the single SCR reactants. It turned out that the activity decrease due to water addition can be divided into a reversible inhibition and an irreversible deactivation. Inhibition is caused by molecular adsorption of water. TPD studies showed that water can adsorb competitively with both ammonia and nitric oxide. Additional kinetic experiments revealed that adsorbed ammonia is present in excess on the catalyst surface, even in the presence of water. Reduced nitric oxide adsorption is responsible for the observed reversible decrease in the reaction rate; the fractional reaction order changes from 0.79 in the absence of water to 1.07 in its presence. Deactivation is probably due to the dissociative adsorption of water, resulting in the formation of additional surface hydroxyls. As the amount of surface hydroxyls formed is limited to a saturation level, the deactivating effect on the catalyst is limited too. The additional hydroxyls condense and desorb in the temperature range 525–775 K, resulting in a lower degree of deactivation at higher temperature. A high temperature treatment at 775 K results in a complete regeneration. The amount of surface hydroxyls formed per unit surface area decreases at increasing MnO_x-loading. The selectivity to the production of nitrogen is enhanced significantly by the presence of gas phase water.     

基于非线性规划的指数自回归模型的辨识

讨论了指数自回归模型的辨识问题，证明了该模型最小二乘估计的目标函数的非凸性，并给出了使该函数为凸的条件，最后给出了辨识该模型的算法及该算法的收敛性，并以数值例子加以说明。     

三峡库区湖北四县水土资源综合开发利用与水土流失防治对策研究

三峡库区湖北宜昌、秭归、兴山、巴东四县幅员面积１１５８９．３平方公里，总人口数１６６．０２万人，三峡水库形成后，淹没土面积７４．４７平方公里，涉及８．９４万人，规划农业生产安置２．８万人。本文以四县土地资源利用现状主和环境容量的分析为基础，进行三峡库区移民安置对水土流失的影响评价，论证综合开发利用水土资源，水土保持与开发性移民相结合，是扩大库区人口环境容量的必由之路，研究制订出移民安置与水土资源的     

具有减少辨识参数的随机多变量极点配置自适应控制器

本文提出了一种新的限制输出个数减少随机多变量自适应控制中辨识参数的方法，并给出了减少辨识参数的极点配置自适应算法。虽然采用ｎ个输入１个输出的减少辨识参数的模型来设计控制器，但所提出的控制器能够保证被控系统的几个输出跟踪参考输入信号，仿真结果表明，所提出的方法是成功的。     

3D Motion Estimation and Motion Fusion by Affine Region Matching

In this paper,a new method is presented for 3D motion estimation by image region correspondences using stereo cameras.Under the weak perspectivity assumption.we first employ the moment tensor theory (Cyganski and Orr^[11]) to compute the monocular affine transformations relating images taken by the same camera at different time instants and the binocular affine transformations relating images taken by different cameras at the same time instant.We then show that 3D motion can be recovered from these 2D transformations.A space-time fusion strategy is proposed to aim at robust results.No knowledge of point correspondences if requred in the above processes and the computations involved are linear.To find corresponding image regions,new affine invariants,which show stronger invariance,are derived in term of tensor contraction theory.Experiments on real motion images are conducted to verify the proposed method.     

On the boundary-layer control through momentum injection: Studies with applications

The concept of moving surface boundary-layer control, as applied to a Joukowsky airfoil, is investigated through a planned experimental programme complemented by numerical studies. The moving surface was provided by rotating cylinders located at the leading edge and/or trailing edge as well as top surface of the airfoil. Results suggest that the concept is quite promising, leading to a substantial increase in lift and a delay in stall. Depending on the performance desired, appropriate combinations of cylinder geometry, location and speed can be selected to obtain favourable results over a wide range of angle of attack. Next, effectiveness of the concept in reducing drag of bluff bodies such as a two-dimensional flat plate at large angles of attack, rectangular prisms and three-dimensional models of trucks is assessed through an extensive wind tunnel test-programme. Results show that injection of momentum through moving surfaces, achieved here by introduction of bearing-mounted, motordriven, hollow cylinders, can significantly delay separation of the boundary-layer and reduce the pressure drag. The momentum injection procedure also proved effective in arresting wind-induced vortex resonance and galloping type of instabilities. A flow visualization study, conducted in a closed-circuit water tunnel using slit lighting and polyvinyl choride tracer particles, adds to the wind-tunnel and numerical investigations. It shows, rather dramatically, the effectiveness of the moving surface boundary-layer control (MSBC). The Sabita Chaudhury Memorial Lecture The models were fabricated in the Mechanical Engineering Workshop. The assistance of M/s E Abell, P Hurren and D Camp in the design and construction of the models is gratefully acknowledged. The investigation was supported by the Natural Sciences and Engineering Research Council of Canada, Grant No. A-2181.     

非线性系统鲁棒吸引的动态补偿方法

考虑非线性不确定系统的鲁棒吸引问题,借助于动态输出反馈,构造了两类控制律。这两类控制律分别可使相应的闭环系统被一任意小的区域鲁棒吸引,或被一预先设置的区域有限吸引。