双护盾掘进机洞轴线纠偏实例

在利用双护盾隧洞掘进机进行同忻煤矿主斜井开挖的过程中发生了卡机事故,开挖斜井的轴线偏离了正确的方向。文中分析了事故发生的原因,介绍了采取的掘进机整机后退的措施,使得成功地摆脱了困境。     

Some new error inequalities for a generalized quadrature rule of open type

Some new error inequalities for a generalized quadrature rule of open type are established. Especially, two sharp inequalities are derived when n is an odd and an even integer, respectively.     

A systematic approach to improve multiple Lyapunov function stability and stabilization conditions for fuzzy systems

This paper presents a systematic approach for decreasing conservativeness in stability analysis and control design for Takagi-Sugeno (TS) systems. This approach is based on the idea of multiple Lyapunov functions together with simple techniques for introducing slack matrices. Unlike some previous approaches based on multiple Lyapunov functions, both the stability and the stabilization conditions are written as linear matrix inequality (LMI) problems. The proposed approach reduces the number of inequalities and guarantees extra degrees of freedom to the LMI problems. Numeric examples illustrate the effectiveness of this method.     

Probability of graphs with large spectral gap by multicanonical Monte Carlo

Graphs with large spectral gap are important in various fields such as biology, sociology and computer science. In designing such graphs, an important question is how the probability of graphs with large spectral gap behaves. A method based on multicanonical Monte Carlo is introduced to quantify the behavior of this probability, which enables us to calculate extreme tails of the distribution. The proposed method is successfully applied to random 3-regular graphs and large deviation probability is estimated.     

An LMI approach to constrained optimization with homogeneous forms

This paper considers the problem of determining the minimum Euclidean distance of a point from a polynomial surface in . It is well known that this problem is in general non-convex. The main purpose of the paper is to investigate to what extent linear matrix inequality (LMI) techniques can be exploited for solving this problem. The first result of the paper shows that a lower bound to the global minimum can be achieved via the solution of a one-parameter family of linear matrix inequalities (LMIs). It is also pointed out that for some classes of problems the solution of a single LMI problem provides the lower bound. The second result concerns the tightness of the bound. It is shown that optimality of the lower bound amounts to solving a system of linear equations. An application example is finally presented to show the features of the approach.     

语言在网络语境中的变异

本文从词形变异、语义变异、语法变异三个方面分析了语言在网络语境中的变异及变异的原因,并指出,网络语言的变异已辐射到网络之外的语境中。作者还就如何看待网络语言的变异提出了一些看法。     

两个分式型不等式的拓广与深化

对两个分式型不等式的参指数α作适当拓广,得到两个一般的分式型不等式,同时对新的分式型不等式的变元ai与bi作巧妙的代换,参指数α与β作适当变形,得到了许多著名的不等式,甚至是其反向不等式,是其加强式,使此类问题系统化、深刻化.     

PNN测井监测气液界面在马北一号注气油藏中的应用

马北一号油田为底水油藏,注水开发效果较差。为提高采收率,采用顶部注烃气重力驱技术理念,在油田首次开展了2个井组注气实验。及时掌握注气后气液界面移动情况,对于优化射孔生产方案具有较强的指导意义。PNN测井在套管井中监测地层气液界面具有较强的优势,主要通过长短源距探头计数率叠合,在气层出现较明显的离差进行判断和分析。在马北一号油田开展时间推移PNN测井26井次,及时掌握了试验井组气液界面运移情况和受效方向,为进一步优化生产方案提供了科学依据。