自控温加热带的研制

研究了炭黑含量、辐照剂量以及体系共结晶性对以高密度聚乙烯/乙烯 丙烯酸乙烯酯共聚物为基材的自控温加热带电阻率及电热稳定性能的影响,以及加工条件和后处理工艺对材料电性能的影响。结果表明,50～80kGy的辐照剂量为本体系提供优异的电热稳定性,适当的加工及后处理工艺能大大改善该体系的导电性。     

6m大容积焦炉烘炉实践与体会

介绍了 6 m大容积焦炉由冷态到转入正常加热温度的烘炉操作过程中 ,按照一定的升温曲线 ,通过对焦炉热工和炉体膨胀的科学管理 ,确保新建焦炉顺利由冷态过渡到生产状态。     

Effect of test frequency and water content on localized crack-tip heating in nylon-6,6

Fatigue crack propagation (FCP) tests were conducted at various frequencies on nylon-6,6 specimens equilibrated over a range of moisture levels to determine the crack growth rates and the crack-tip temperatures as a function of water content. Frequency-sensitivity was correlated with the amount of crack-tip heating taking place, with crack-tip temperature being found to depend strongly on the estimated loss compliance, D″, of the material. The frequency-sensitivity of FCP in nylon was seen also to be affected by mean stress, suggesting that creep processes are often significant in FCP of nylon.     

具有数据包丢失的离散随机不确定系统的线性最优满阶估值器

研究了具有数据包丢失和随机不确定性离散随机线性系统的状态估计问题.其中数据包丢失是随机的,且满足Bernoulli分布,系统矩阵中的随机不确定性由一个白色乘性噪声来描述.首先,通过配方方法,提出了最小均方意义下的无偏最优线性递推满阶滤波器.所提出的滤波器用到了当前时刻和最近时刻接收到的观测来保证线性最优性.与多项式滤波和增广滤波器相比,本文的滤波器具有较小的计算负担.然后,基于所获得的线性滤波器推导了线性最优预报器和平滑器.进一步研究了线性最优估值器的渐近稳定性,给出了稳态特性存在的一个充分条件.最后,通过两个仿真例子验证了所提估计算法的优越性.     

串联感应加热电源相角保护

数字感应加热电源在工业中一般采用串联负载与PFM调功方式。串联负载谐振与PFM调功方式要求逆变器频率稳定工作在感性区,但在实际工作过程中逆变器频率可能会由感性区越过谐振点滑入容性区,引起逆变器发生"炸管"现象。为了防止"炸管"现象的发生,在谐振点附近的感性区设置限相区,当频率进入限相区经PI处理使其稳定工作在感性区达到保护逆变器的目的。通过DSP实验平台测试,限相区的设置可以很好的保护逆变器使其稳定工作在感性区。     

Differential geometry properties of lines of curvature of parametric surfaces and their visualization

We present algorithms for computing the differential geometry properties of lines of curvature of parametric surfaces. We derive a unit tangent vector, curvature vector, binormal vector, torsion, and algorithms to evaluate their higher-order derivatives of lines of curvature of parametric surfaces. Among these quantities, it is shown that the curvature and its first derivative of the lines of curvature lend a hand for the formation of curved plates in shipbuilding. We also visualize the twist of lines of curvature, which enables us to observe how much the osculating plane of the line of curvature turns about the tangent vector.     

太阳能供热系统优化设计的相关问题研究

随着我国建筑总量和建筑能耗的快速增长,传统的供热方式已难以满足建筑供热的需求,而利用太阳能为建筑物供热,则可获得良好的节能和环保效益。就太阳能供热系统优化设计的相关问题进行了分析和研究,以期能为太阳能供热技术的推广和应用提供一定的理论依据。     

集中供热系统适量供热调节技术

集中供热的采暖用户实行计量收费并且具有自调节能力以后,必须要有与用户调节相匹配的运行调节手段,才能实现系统的适量供热.结合集中供热常用的系统形式,分别分析用户、热网及热源在各种运行方式下的调节特性及节能潜力,得出室内系统变流量、循环水泵变转速运行时节能量最高,并给出循环水泵定转速运行及变转速运行下的控制系统方框图.最后指出,应该针对新型供热系统和旧有供热系统的特点,制定相应的整体综合调节策略,才能实现节能最佳.     

HP nonlinear guidance law design based on smooth sliding mode control

To eliminate the perturbation of interceptor detection induced by aerodynamic heating,the head pursuit (HP) guidance law for three-dimensional interception was presented. The guidance law positioned the interceptor ahead of the target on its flight trajectory,and the speed of interceptor was required to be lower than that of the target. On the basis of a novel head pursuit three-dimensional guidance model,a nonlinear guidance law was developed based on smooth sliding mode control theory. At the same time,a special observer was designed to estimate the target acceleration,and a numerical example on maneuvering ballistic target interception verified the effectiveness of the presented guidance law.     

分时控制MOSFET固态高频感应加热电源研究

研究了一种采用分时控制方法的MOSFET固态高频感应加热电源,电源输出频率是功率器件工作频率的n倍(采用n个桥分时工作)。利用MATLAB/SIMULINK实现了分时控制的仿真,分析了分时控制的工作状态,对器件功耗进行了理论推导,并对如何实现分时控制进行了介绍,且根据仿真画出了并行控制和分时控制2种控制方式下MOSFET器件损耗的曲线图。仿真结果表明分时控制在实现固态感应加热电源的高频化方面优于并行控制。