风险分析的尖点突变模型

　Aim　To assess simultaneously various risk states of a system. Methods Using the catastrophe and fuzzy theory, the energy and uncertainty in a system are set as two control variables and the function of the system is used as the state variable for analysis. Results and Conclusion A risk analysis model named the cusp model is presented. Various states regarding the safety of the system such as the accident state, no-accident state and miss state can be represented at will on the cusp model.     

不同衬底上低温生长GaN形貌的AFM观察

　Aim　To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of substrates, including sapphire, Si(111),Si(100),GaAs and GaP(111) both on the P face and the Ga face. The growth was performed at low temperatures of below 700℃. XRD, Hall measurement, cathodoluminescence (CL) and atomic force microscopy (AFM) were used to characterise the film properties. Results It was found that the temperature and the nature of substrate materials influence the layer morphology. Conclusion The analysis shows that no apparent relationship exists between the optical properties and layer morphology.     

基于DA算法的二维离散余弦逆变换的ASIC设计

　Aim　To present an ASIC design of DA-based 2-D IDCT. Methods In the design of 1-D IDCT is utilized a Chen-based fast IDCT algorithm, and multiplier accumulators based on distributed algorithm contributes in reducing the hardware amount and in enhancing the speed performance. Results and Conclusion VHDL simulation, synthesis and layout design of system are implemented. This 2-D IDCT ASIC design owns best timing performance when compared with other better designs internationally. Results of design prove to be excellent.     

用于车辆传动的金属材料的疲劳试验及统计方法

　Aim　To improve the efficiency of fatigue material tests and relevant statistical treatment of test data. Methods Least square approach and other special treatments were used. Results and Conclusion The concepts of each phase in fatigue tests and statistical treatment are clarified. The method proposed leads to three important properties. Reduced number of specimens brings to the advantage of lowering test expenditures. The whole test procedure has more flexibility for there is no need to conduct many tests at the same stress level as in traditional cases.     

极性反转瞬态电场的数值算法及应用

　Aim　To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand-voltage strength of different insulation structures. Methods The transient process of polarity reversal is analyzed, considering the anisotropic property of oil-immersed press-board, a new finite element model based on Galerkin method is presented and verified. The model developed is applied to calculate the electric field distribution in four typical winding end structures of the converter transformer. Results The whole-ring structure possesses the best insulation characteristics. Conclusion By introducing reasonable insulation components, insulation strength with the same surrounding sizes can be improved more than 30%.     

矿井通风网络分析的遗传算法

　Aim　To determine the global optimal solution for a mine ventilation network under given network topology and airway characteristics. Methods The genetic algorithm was used to find the global optimal solution of the network. Results A modified genetic algorithm is presented with its characteristics and principle. Instead of working on the conventional bit by bit operation, both the crossover and mutation operators are handled in real values by the proposed algorithms. To prevent the system from turning into a premature problem, the elitists from two groups of possible solutions are selected to reproduce the new populations. Conclusion The simulation results show that the method outperforms the conventional nonlinear programming approach whether from the viewpoint of the number of iterations required to find the optimum solutions or from the final solutions obtained.     

节理岩体弹塑性动态有限元分析

　Aim　To study the elastic-plastic dynamical constitutive relations about a jointed rock mass under explosion load and its computer simulation. Methods Stress history is taken into account and stresses will follow changes in time during a period of explosion load. According to the principle of static force balance, the corresponding nodal concentrated force is calculated and the nodal displacement is counted. The elastic-plastic dynamic finite element equations are thus obtained. Results A finite element method is given for a jointed rock mass under explosion load. Conclusion The problem of large plastic deformation for jointed rock mass on blasting was efficiently resolved through dynamic finite element analysis and the range of damages by blasting simulated, and this pushes forward the problem to engineering practice.     

约束系统特性对乘员碰撞响应影响的仿真研究

　Aim　To study the influence of restraint system performance upon the occupant's response during impact, and provide a scientific base for occupant restraint system design. Methods In the light of basic theory of multibody system dynamics and impact dynamics on the basis of classical theory of impact, R-W method is adopted to construct the vehicle-occupant system model consisting of fourteen rigid bodies, thirty seven DOFs and slip joints for the simulation. A software named SVC3D(3-dimensional simulation of vehicle crash) is developed in the FORTRAN language. Results The results of simulation have a good coincidence with those of tests and the restraint system with low elongation webbing and equipped with pretensioner provides better restraint effect for the occupant. Conclusion The model of vehicle-occupant multibody system and SVC3D are suitable for use. Occupant should be belted with low elongation webbing to a certain degree and occupant restraint system should be equipped with pretensioner.     

热处理对共混物中尼龙6熔融行为的影响

　Aim　To investigate the multiple melting behavior of polyamide-6(PA-6) in polyamide-6/linear low density polyethylene blends crystallized from the crystal-amorphous state. Methods The effects of annealing temperature, annealing time, heating rate, and the step-wise annealing were measured by DSC. Results and Conclusion There exists a critical heating rate affecting the middle temperature melting peak. When annealed at the temperature close to the melting peak, the main melting peak of PA-6 shifted to a higher temperature. Within a short time, annealing time has much effect on neat PA-6 but little effect on PA-6 in the blends. Addition of PE results in a decreasing in the height of melting peak. These phenomenon show that the melting behavior of PA-6 was affected by PE, compatibilizer, as well as thermal treatment.     

Optimal Guaranteed Cost Control via Static Output Feedback for Uncertain Discrete Time Systems

目的研究在状态空间模型中的状态及控制矩阵中含有范数有界参数不确定线性离散系统的最优保价静态输出反馈控制问题．方法给出了系统二次代价指标的一个上界,并利用拉格朗日乘子法优化了该界．结果与结论给出了保证闭环系统二次稳定且使得二次代价指标界达到最小的静态输出反馈控制器存在的充分条件．并提供了一个求解输出反馈增益的数值算法．     

一种基于预测补偿的人工智能伺服控制系统

将神经元与模糊控制器相结合 ,利用自适应神经元 (APE)预测输出信号yp(t +1)与目标值R比较后 ,生成误差预测值ep(t +1) ,即预测超调量的负补偿量 ,补偿模糊控制器输出的控制信号ec,减小超调量 .在此基础上设计了基于预测补偿的人工智能控制器 ,从而达到了克服控制系统稳定性与快速性矛盾的目的     

PLC控制系统的参数显示研究

目的　为可编程逻辑控制器(ProgrammableLogicController简称PLC)设计实时参数显示装置.方法　通过动态扫描实现设计要求.结果　用德国西门子公司的SIMATICS7-300可编程控制器设计出了符合要求的显示装置.结论　经过调试,该装置性能可靠,成本低廉,有推广价值.     

龙门刨电气技术改造研究

介绍了采用晶闸管直流调速系统取代直流发电机电动机组拖动系统,采用可编程序控制器取代继电接触控制系统,对龙门刨电气控制系统进行技术改造的方法,改造后的龙门刨在降低能耗,减少噪音等方面具有良好的经济效益和社会效益。     

行车精确泊位测控装置设计

目的　控制行车自动准确地往返于两固定点间装货和卸货 .方法　用对射式红外光电传感器检测设置的遮光挡块 ,获得位置信号 .通过单片机控制及软件滤波技术来提高检测装置的性能 .结果　经实际使用 ,该装置泊位误差小于 2 cm,且抗干扰能力强 .结论　该装置使用无接触检测光电传感器 ,寿命长、故障率低、泊位精确     

电梯机械振动的频域最优主动控制

采用振动的主动控制方法对电梯机械振动进行控制。按频域Ｈ２最优控制来设计控制律,使闭环系统的从外扰至系统的受控输出的传递函数阵的Ｈ２范数为最小。闭环系统采用电梯轿厢的振动加速度作为反馈信号,将使振动的主动控制在工程上易于实现。数值仿真结果表明,系统的闭环传递函数能得到很大的抑制,频域最优控制的效果是明显的,有效的。与时域最优来设计控制律相比,它具有工程上的广泛的优点。     

基于免疫反馈机理的温度自动控制研究

基于生物免疫系统的反馈机理，提出了一种用免疫控制器与传统PI控制器相结合的复合控制方法，印将传统PJ控制器与免疫控制器相“串联”，在传统PI控制器参数已经优化的情况下，用免疫控制器对其输出进行“再处理”．并针对实际系统提出了一种限制超调量的误差参数函数，介绍了控制系统参数整定的方法．仿真和实验表明，这种复合控制的方法能有效地改善金属有机化合物化学气相淀积系统温度的控制性能．     

大迟延过程的预测智能控制

针对大迟延过程,提出一种预测与智能控制相结合的新型控制器。该控制器是根据偏差状况及预测变化趋势,通过模仿人的控制思维方式来选择相应控制量,故可降低对预测模型精度要求。将该控制器用于锅炉过热汽温控制中,仿真实验表明：该控制器的控制品质优于常规控制算法,并具有较强鲁棒性。     

基于自抗扰控制器的网络控制系统设计

网络控制系统具有很多不确定性,对控制器的鲁棒性设计提出了新的挑战。基于自抗扰控制技术设计出了具有较强鲁棒性的网络控制器。自抗扰控制器的设计独立于对象模型,在工程应用中具有较强的实用性。仿真结果验证了控制器的鲁棒性。     

工程数据库中长事务的并发控制

目的　解决工程数据库中长事务的并发控制 .方法　采用一种嵌套事务模型及基于锁的并发控制算法 .结果　给出了该嵌套事务模型的实现 ,并分析了该方法对长事务并发控制的可行性 .结论　采用该方法解决了工程长事务的并发性