我国人工湿地研究进展及在寒冷地区的应用

针对人工湿地处理技术及其工程的应用,文中系统论述我国在人工湿地研究方面的最新进展及亟待解决的关键技术问题。通过分析人工湿地的特点及研究现状,重点探讨我国北方寒冷地区人工湿地的技术的应用,为完善人工湿地系统在我国北方寒冷地区的应用及实施,提供理论指导和技术支持。     

Analysis for a class of singularly perturbed hybrid systems via averaging

A class of singularly perturbed hybrid dynamical systems is analyzed. The fast states are restricted to a compact set a priori. The continuous-time boundary layer dynamics produce solutions that are assumed to generate a well-defined average vector field for the slow dynamics. This average, the projection of the jump map in the direction of the slow states, and flow and jump sets from the original dynamics define the reduced, or average, hybrid dynamical system. Assumptions about the average system lead to conclusions about the original, higher-dimensional system. For example, forward pre-completeness for the average system leads to a result on closeness of solutions between the original and average system on compact time domains. In addition, global asymptotic stability for the average system implies semiglobal, practical asymptotic stability for the original system. We give examples to illustrate the averaging concept and to relate it to classical singular perturbation results as well as to other singular perturbation results that have appeared recently for hybrid systems. We also use an example to show that our results can be used as an analysis tool to design hybrid feedbacks for continuous-time plants implemented by fast but continuous actuators.     

Optimal control of unknown nonaffine nonlinear discrete-time systems based on adaptive dynamic programming

An intelligent-optimal control scheme for unknown nonaffine nonlinear discrete-time systems with discount factor in the cost function is developed in this paper. The iterative adaptive dynamic programming algorithm is introduced to solve the optimal control problem with convergence analysis. Then, the implementation of the iterative algorithm via globalized dual heuristic programming technique is presented by using three neural networks, which will approximate at each iteration the cost function, the control law, and the unknown nonlinear system, respectively. In addition, two simulation examples are provided to verify the effectiveness of the developed optimal control approach.     

联合变换相关器傅里叶变换镜头光学系统设计

针对联合变换相关器的目标识别的设计要求,为提高联合变换相关器光学特性,本文提出三片式傅里叶变换透镜的设计。该设计根据电寻址液晶EALcD和CCD对傅里叶变换透镜的匹配要求确定设计参数。工作波长为O．6328,um,焦距200mm,全视场角4°,相对孔径1：4。系统引入偶次非球面,使镜头结构紧凑、重量轻、筒长短。设计结果表明：在空间频率501p／mm时,光学系统的MTF大于0．8,接近衍射极限,像质优良,满足联合变换相关器的总体设计要求。     

基于GC—IP2000获取高分辨力增量式编码器的研究

GC-IP2000模拟信号处理器是GEMAC公司为提高电子线路集成度,使产品向小型化发展设计的集成芯片,其特点是可直接与光电系统对接,将获取的正弦和余弦模拟信号,在芯片内部进行修正处理后输出标准的差值方波。本文根据芯片特点,将其应用于伺服控制系统编码器电路部分,用软件程序控制获取角度和位置变化信息,其目的是提高编码器分辨力,进而给伺服控制系统提供可靠的角位移数据。     

约瑟夫森结的线性延时反馈控制分析

考虑电阻-电容分路的约瑟夫森结的线性延时反馈控制,运用非线性动力学理论分析了受控系统平凡解的稳定性。研究表明随着参数的变化,系统的稳定平凡解将会通过Hopf分岔失稳产生周期解,数值仿真验证了理论结果。     

制备方法对负载型FeS/Al_2O_3催化剂催化性能的影响

用原位合成法、水热法、共沉淀法和浸渍沉淀法分别制备了负载型纳米Fe2O3/Al2O3催化剂前驱体,并进一步将其还原和硫化制成FeS/Al2O3催化剂用于H2S分解制氢的反应中,同时用BET、XRD、TPR和IR等对催化剂或前驱体的比表面积、晶相结构、孔径分布、还原性和吸附性等进行了表征。结果表明,原位合成法制备的FeS/Al2O3催化剂平均粒径较小,比表面积较大,有利于催化剂的还原和硫化,H2S在该催化剂表面形成的化学吸附态较强,H2S容易发生解离,初活性高于其他方法制备的催化剂,反应60 h后催化剂的活性没有出现明显下降。     

全面预算管理在供电企业的进一步深化应用及思考

全面预算管理是现代企业财务管理的重要组成部分,企业可以通过全面预算管理来监控战略目标的实施进度,控制开支,预测企业的现金流量与利润,是企业降低风险、提高经济效益与管理水平的重要方法。建立适合市级供电企业管理需要的全面预算管理体系,是企业管理创新的需要。文章就市级供电企业推行全面预算管理的运用状况及存在的问题进行分析,同时提出改进建议。     

数值级数法求解一类时滞微分方程

采用级数形式给出半离散差分格式在网格节点处的数值解以及计算级数中的每一项递推公式。离散后差分格式收敛性、稳定性分析表明该格式收敛且稳定,数值算例验证该方法有效。     

The use of graphene oxide membranes for the softening of hard water

Strong chemical interactions between the oxygen-containing functional groups on graphene oxide (GO) sheets and the ions of divalent metals were exploited for the softening of hard water. GO membranes were prepared and evaluated for their ability to absorb Ca²⁺ and Mg²⁺ ions. These GO membranes can effectively absorb Ca²⁺ ions from hard water; a 1 mg GO membrane can remove as much as 0.05 mg Ca²⁺ ions. These GO membranes can be regenerated and used repeatedly.