Magnetostratigraphic study of Cretaceous depositional succession in the northern Kuqa Depression, Northwest China

Stratigraphic studies on the depositional succession in the Kuqa Depression can be traced back to as early as 1950s[1], however, there are still some disputes about chronostratigraphic division of the Bashenjiqike For- mation because of the paucity of fos…     

Robust output regulation problem for discrete-time linear systems with both input and communication delays

Recently, the robust output regulation problem for continuous-time linear systems with both input and communication time-delays was studied. This paper will further present the results on the robust output regulation problem for discrete-time linear systems with input and communication delays. The motivation of this paper comes from two aspects. First, it is known that the solvability of the output regulation problem for linear systems is dictated by two matrix equations. While, for delay-free systems, these two matrix equations are same for both continuous-time systems and discrete-time systems, they are different for continuous-time time-delay systems and discrete-time time-delay systems. Second, the stabilization methods for continuous-time timedelay systems and discrete-time time-delay systems are also somehow different. Thus, an independent treatment of the robust output regulation problem for discrete-time time-delay systems will be useful and necessary.     

Stability analysis of the simplest Takagi-Sugeno fuzzy control system using circle criterion

A frequency-domain-based sufficient condition is derived to guarantee the globally asymptotic stability of the simplest Takagi-Sugeno (T-S) fuzzy control system by using the circle criterion. The analysis is performed in the frequency domain, and hence the condition is of great significance when the frequency-response method, which is widely used in the linear control theory and practice, is employed to synthesize the simplest T-S fuzzy controller. Besides, this sufficient condition is featured by a graphical interpretation, which makes the condition straightforward to be used. Comparisons are drawn between the performance of the simplest T-S fuzzy controller and that of the linear compensator. Two numerical examples are presented to demonstrate how this sufficient condition can be applied to both stable and unstable plants.     

一种改进的三角模糊数互补判断矩阵的排序方法

在传统的三角模糊数互补判断矩阵排序方法的基础上,结合三角模糊数均值的概念,提出了一种改进的排序方法。该方法通过三角模糊数互补判断矩阵以及相应的概率分布矩阵,计算得到模糊均值矩阵,从而将三角模糊数互补判断矩阵的排序问题转换为模糊均值矩阵的排序问题,然后对模糊均值矩阵利用权的最小平方法计算排序向量。通过计算三角模糊数均值,有效地减少了判断过程中的不确定性。给出了该方法的具体应用步骤,仿真算例表明该方法易于实现,具有很好的可操作性。     

嫦娥二号平动点间转移轨道方案研究

针对我国嫦娥二号卫星拓展任务需求,研究了卫星由日地L2点向L1点的转移轨道方案。基于卫星真实星历,考虑各种摄动因素,借助不变流形理论和微分修正方法,设计了嫦娥二号在日地平动点L1和L2之间的转移轨道,提出了便于理解和工程应用的平动点间直接转移方式,研究了真实力模型下平动点Lissajous轨道的不变流形转移方式,对比了两种转移方式的出发速度增量、转移时间与出发时刻的关系。研究表明,嫦娥二号可以通过直接转移方式或者借助不变流形进入日地L1点Lissajous轨道,直接转移方式下有42天出发机会,基于不变流形方式下最短转移时间为210天,对应速度增量5.776 m/s,最小速度增量可达0.024 m/s。研究结果可直接应用于我国嫦娥二号拓展任务的轨道设计与控制,并为我国后续平动点等深空探测任务提供有益借鉴.     

求解0-1背包问题的二进制狼群算法

狼群算法(wolf pack algorithm, WPA)源于狼群在捕食及其猎物分配中所体现的群体智能,已被成功应用于复杂函数求解。在此基础上,通过定义运动算子,对人工狼位置、步长和智能行为重新进行二进制编码设计,提出了一种解决离散空间组合优化问题的二进制狼群算法（binary wolf pack algorithm, BWPA）。该算法保留了狼群算法基于职责分工的协作式搜索特性,选取离散空间的经典问题--0-1背包问题进行仿真实验,具体通过10组经典的背包问题算例和BWPA算法与经典的二进制粒子群算法、贪婪遗传算法、量子遗传算法在求解3组高维背包问题时的对比计算,例证了算法具有相对更好的稳定性和全局寻优能力。     

低成本纳米复合材料70％ CeO2·30％ NiO的合成及其催化性能的研究

分别选用水热,浸渍,柠檬酸络合燃烧,共沉淀方法合成了多种前驱体,再经过600 ℃煅烧处理4h,成功合成出纳米复合材料70％ CeO2·30％ NiO,对这些复合材料进行系统的XRD、BET、H2-TPR、O2-TPD表征和CO催化氧化性能测试.     

支持风险投资的政策体系和制度设计研究

风险投资产业的蓬勃发展,需要政府部门的大力支持和推进。首先对现有国内外支持风险投资的政策进行了分析和评价,进而探讨了促进风险投资的制度设计。通过整合一系列的资源要素,形成系统化的制度环境,我国未来的风险投资产业将能够获得长足的发展。     

创新工程技术支撑科学发展

回顾了近年特别是2008年中国在信息、能源、制造业及探索宏观、微观世界等领域所取得的重大科学技术进步和工程创新成就；指出了严重自然灾害对科学技术和工程的检验与启示；提出了我国工程科技界值得思考的几个问题，展望了未来我国工程技术的创新使命。