A class of discrete time generalized Riccati equations

In this paper, a class of discrete-time backward non-linear equations defined on some ordered Hilbert spaces of symmetric matrices is considered. The problem of the existence of some global solutions is investigated. The class of considered discrete-time non-linear equations contains, as special cases, a great number of difference Riccati equations both from the deterministic and the stochastic framework. The results proved in the paper provide the sets of necessary and sufficient conditions that guarantee the existence of some special solutions of the considered equations as: the maximal solution, the stabilizing solution and the minimal positive semi-definite solution. These conditions are expressed in terms of the feasibility of some suitable systems of linear matrix inequalities (LMI). One shows that in the case of the equations with periodic coefficients to verify the conditions that guarantee the existence of the maximal or the stabilizing solution, we have to check the solvability of some systems of LMI with a finite number of inequations. The proofs are based on some suitable properties of discrete-time linear equations defined by the positive operators on some ordered Hilbert spaces chosen adequately. The results derived in this paper provide useful conditions that guarantee the existence of the maximal solution or the stabilizing solution for different classes of difference matrix Riccati equations involved in many problems of robust control both in the deterministic and the stochastic framework. The proofs are deterministic and are accessible to the readers less familiarized with the stochastic reasonings.     

概率鲁棒镇定控制器的研究

将统计学习理论中的经验概率一致收敛特性应用到鲁棒控制中,针对具有实参数不确定性的控制系统,研究了概率鲁棒镇定控制器的设计问题.给出了设计概率鲁棒镇定控制器的前提条件,采用基于经验概率一致收敛特性的随机化算法设计概率鲁棒镇定控制器的具体步骤和方法.研究表明,与传统方法相比,在概率意义下采用随机化算法设计概率鲁棒镇定控制器具有设计方法简单、计算量小的优点.计算实例表明了该算法的有效性.     

抗滑桩抗滑阻力的优化计算方法

针对传统抗滑阻力计算方法中存在的缺陷,以不平衡推力传递系数法为基础,提出了一种简便有效的抗滑桩抗滑阻力优化计算方法,即矩阵数组法,该方法不仅可用于单排抗滑桩的设计计算,获得最小的抗滑阻力和最佳设桩位置,而且可用于多（双）排桩的优化设计计算。通过工程实例比对,分析结果显示,矩阵数组法比传统方法更科学。在应用抗滑桩治理滑坡工程设计计算中,将矩阵数组法与有限元法进行结合,则计算结果更可靠、更合理。     

渤海海上窄条状油田稳油控水研究及应用

渤海海上窄条状油田含油层系为新近系明化镇组下段,为分支河道型浅水三角洲沉积,具有平面上呈窄条状分布(平均宽度300 m)、纵向叠合程度差、厚度薄、层间矛盾突出、含水上升快等特点,且国内外对该类型油田并无成熟经验可以借鉴,导致开发难度大。近年来渤海针对窄条状油田含水上升速度快的特点,开展了该类型油田稳油控水技术攻关研究:推导了窄条状油田注采井网见水时间公式,并利用均衡驱替原理对注采井组进行调整;研究了周期注水在窄条状油田中低含水期的应用,取得了较大进展。已经成功应用到了渤海海上窄条带状油田中,含水上升率明显下降,已实现累增油40万m3,取得了很好的应用效果。     

Neutral Boryl Radicals in Mixed-Valent B(III)Br-B(II) Adducts

The general strategies to stabilize a boryl radical involve single electron delocalization by π-system and the steric hinderance from bulky groups. Herein, a new class of boryl radicals is reported, with intramolecular mixed-valent B^(III)Br-B^(II) adducts ligated by a cyclic (alkyl)(amino)carbene (CAAC). The radicals feature a large spin density on the boron center, which is ascertained by EPR spectroscopy and DFT calculations. Structural and computational analyses revealed that the stability of radical species was assisted by the CAAC ligand and a weak but significant B(III)Br-B(II) interaction, suggesting a cooperative avenue for stabilization of boryl radicals. Two-electron reduction of these new boryl radicals provides C−H insertion products via a borylene intermediate.     

THE NEIGHBORHOOD IN STABILIZING HIGHER PERIOD ORBITS FOR DISCRETE CHAOTIC DYNAMICS

1IntroductiollConsiderableattentionhasbeenpaidrecentlytothecontrolofchaoticsystem.Inthispaper,weuseappropriateperturbation(localfeedbackcontrol)tostabilizetheunstablehigherperiodicorbitswhichispresentedbyPaskatoet.al.[8].Ouraimistoinitiallypresenttheestimationofneighborhoodofaperiod-porbitinwhichthecontrolledsystemremainsstable.ConsiderthenonlineardiscretedynamicalsystemwherexuER'isthestatevariable,N4={no,no l,''3no6NU{0}},andfeC'(NAxR',R').Let2beperiod-ppoint,i.e.fi(n,~)=2,then{2,f(n,2)…     

填土边坡稳定性评价及其抗滑桩设计方案的探讨

在介绍一中型填土边坡破坏的基础上，对其稳定性进行了分析评价，并应用抗滑桩的极限承载理论和绕流阻力理论探讨了该边坡的支护设计，对该土质边坡，提出了一套具有一定参考价值和针对性的抗滑桩设计方案。     

振冲法在粉煤灰坝基上的应用

本文介绍应用振冲法加固粉煤灰的坝基设计和施工,对试验成果作了理论分析,对振冲机理中尚未深刻认识的若干问题加以探讨.     

大型光学惯性稳定跟踪仪器稳像精度测试系统原理方案探讨

本文主要探讨大型光学惯性稳定跟踪仪器稳像精度或瞄准线稳定精度测试原理方案设想及其框图、稳像精度计算公式及本测试系统的关键技术。     

代数Riccati方程可稳解的条件数

１．引言 关于代数Ｒｉｃｃａｔｉ方程（ＡＲＥ）的研究是大量的．从数值角度看,有关数值方法,扰动理论的研究已比较深入．而关于条件数理论的研究则还不多［３］,［６］． Ｒｙｅｒｓ［１］研究了时连续代数 Ｒｉｃｃａｔｉ方程可稳解的条件数; Ｋｅｎｎｅｙ和 Ｈｅｗｅｒ［３］讨论了时连续代数 Ｒｉｃｃａｔｉ方程（以下简称 ＣＴＡＲＥ）可稳解的敏度分析,给出了一阶扰动界,引进了条件数; Ｓｕｎ［６］从最佳向后扰动理论角度研究了时离散代数Ｒｉｃｃａｔｉ方程（以下简称ＤＴＡＲＥ）可稳解的条件数;徐树方［８］针对 ＣＴＡ…