Tensile properties,morphology, and thermal behavior of PVC composites containing pine flour and bamboo flour

Composites of unplasticized poly(vinyl chloride) (PVC) blended with bamboo flour and pine flour, respectively, were prepared in a batch mixer followed by compression molding. The effects of wood flour fillers on the morphology, static mechanical properties, and thermal properties of the composites were investigated. Compared with neat PVC resin, the introduction of both bamboo flour and pine flour significantly improved the stiffness of the composites, while decreasing the tensile strength to some extent. Tensile tests showed that pine flour–filled composites exhibited better mechanical properties than those filled with bamboo flour with the same particle size at the same loading level. Scanning electron microscopic examination revealed good dispersion and alignment tendency of short pine fiber within the composites at a lower loading level. Moreover, experimental results indicated that both bamboo flour and pine flour additions showed no obviously adverse effect on the thermal stabilities of these composites. Based on the comprehensive properties, these composites meet the need of woodlike material for use as wood structures. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1804–1811, 2004     

三容系统的解耦神经网络PID控制

三容水箱是常见的非线性强耦合系统,利用一种非线性动态解耦的方法对其进行解耦(其特点是能利用非线性补偿的方式将该类系统各回路输入与输出之间完全解耦),然后采用基于BP神经网络的PID控制策略对其进行控制,并利用MATLAB进行仿真。仿真结果证明解耦的有效性,表明了BP神经网络的PID算法比传统的数字PID具有更强的抗扰动性。     

基于FCM-ARIMA的多阶段退化设备寿命预测研究

针对多阶段退化设备工作过程的退化特性,通过分析总结多阶段退化设备模型的研究进展,分析了多阶段退化设备寿命预测的特点和准确性影响因素,基于上述工作,提出了一种FCM-ARIMA的拐点估计与寿命预测方法,将FCM与ARIMA相结合,首先通过FCM估计设备退化状态的拐点,将退化状态划分成不同的阶段,之后由ARIMA对设备监测数据进行基于拐点分段的寿命预测,并通过实例与未进行拐点估计的方法相比较,结果表明,使用所提出的方法,有效提高了寿命预测的准确度.     

水平地震作用下地下结构考虑转动时的动力响应

利用分析力学的Lagrange方程,推导了地下结构在水平地震作用下同时考虑结构的平动和转动效应的运动方程.为了简化计算,将地下结构假定为矩形刚体,地基采用温克尔弹性地基模型,且不考虑结构与周围土介质的阻尼作用.首先得到了地下结构与土相互作用时的动能和势能,然后利用分析力学的Lagrange方程推导出了结构的运动方程.通过算例研究地下结构在水平地震作用下考虑转动分量和不考虑转动分量时的受力差别.     

鞍山深部铁矿综合地球物理研究

在我国众多沉积变质型铁矿矿床中,鞍山铁矿以其成矿作用和地质、地球物理特征具有明显的代表性。通过开展航空物探工作,确定了磁异常范围和重力异常区域,并通过在异常区域开展可控源音频大地电磁法查证工作,目的是研究异常成因、深部构造及推断可能隐伏铁矿体的埋深、宽度、规模及产状。通过收集工区地质资料并结合CSAMT勘查成果综合分析,发现深部低阻异常,并初步确定了低阻异常的位置、规模等分布特征及其成因;发现了2个有意义的隐伏低阻异常体,推测是由磁铁矿(化)体引起;基本查明了工区内的地层分布特征;推断了6条隐伏断裂构造及其产状特征;对工区内各类岩矿石露头实施了电性参数测量,获得工区内岩矿石的电性特征。本次工作,为鞍山-本溪地区的铁矿资源潜力的快速评价提供了不可或缺的基础资料,为指导下一步深部勘查工作提供了依据。     

抗干扰电法仪在强电磁干扰环境探测断层的应用

为了给规划中的某新区提供基础地质资料,需查明区内断层的准确位置、产状以及覆盖层厚度。由于区内人文干扰和电磁干扰严重,常规电法仪的重复观测误差太大,不能获得准确数据,故采用伪随机码技术,提高信噪比。运用专业的电法反演软件Res2Dinv进行二维反演,获得相应的二维反演电阻率模型断面。通过分析反演结果并结合已知地质资料,推断了区内断裂的位置、产状等信息,经钻探验证,推断的断层信息准确,为新区规划提供了可靠的基础资料。     

Head Orientation Stability of Underwater Snake-Like Robot Swimming

In prior research,the orientation of head of the snake-like robot is changed according to the sinusoidal wave. To solve this problem,we propose Central Pattern Generator( CPG)-based control scheme with head-controller to stabilize the head of the underwater snake-like robot. The advantage of the CPG-based control scheme with head-controller is that the head of the underwater snake-like robot is direct to the target orientation during swimming. The relation between CPG parameters and orientation stability of head is discussed.The adaptation of the proposed method to environment changes is tested. The influences of CPG parameters and hydrodynamic forces on the orientation offset of head are investigated. The target orientation( the input of headcontroller) with an experimental optimization is calculated through a convenient method. To prove the feasibility of the proposed methodology,the different swimming modes have been implemented in our simulation platform.The results show that the oscillation of head’s orientation is inhibited effectively,and the proposed method has strong adaptation to environment and CPG parameters changes.     

一维炉系统的测试实验

一维炉是一种研究煤的热解燃烧和结渣等方面的实验系统,可用于模拟电厂煤粉的燃烧特性。以元宝山褐煤为燃料,介绍了一维炉的结构和功能,并对系统的可靠性进行了验证,利用烟气分析仪及热重分析仪对燃烧后的尾部烟气及灰渣进行了分析测定。结果表明:尾部烟气含氧量与灰渣可燃部分剩余量均在理论计算值的误差允许范围内,说明一维炉密封良好,系统内各部分正常运行,对维炉的调试和研究具有一定的参考意义。     

On the Survivability of Self-repairing Control System for a Hybrid Underwater Vehicle

A hybrid remotely operated underwater vehicle （HROV） capable of working to the full ocean depth has been developed. In order for the vehicle to achieve a certain survivability level, a self-repairing control system （SRCS） has been designed. It consists of two basic technologies, fault diagnosis and isolation （FDI） and reconfigurable control. For F＇DI, a model-based hierarchical fault diagnosis system is designed for the HROV. Then, control strategies which reconfigure the control system at intervals according to information from the FDI system are presented. Combining the two technologies, it can obtain the fundamental frame of SRCS for the HROV. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, an assessment of the HROV＇ s survivability is vitally needed before it enters operational service. This paper presents a new definition of survivability for underwater vehicles and develops a simple survivability model for the SRCS. As a result of survivability assessment for the SRCS, we are able to figure out the survivability of SRCS and make further optimization about it. The methodology developed herein is also applicable to other types of underwater vehicles.     

基于区间模糊数的普兰店热电厂选址研究

热电厂合理选址将直接关系到电厂的经济运行和可持续发展。本文在构建热电厂选址评价指标体系的基础上,利用区间模糊数评价方法。通过专家群决策将定量和定性信息相结合,得出热电厂选址优先次序。文中作者以普兰店热电厂搬迁选址实例进行实证研究．充分考虑建厂的经济性和平均综合效益,在满足现实热负荷需求和计及决策者偏好的情况下．实现了建厂成本最少化和平均综合效益最大化,得出最佳选址。算例表明把区间模糊数评价方法运用于电厂选址中具有一定得科学性和实用性。