青县电子机箱产业集群核心竞争力评价

根据核心竞争力理论,运用层次分析法,构建了对产业集群的核心竞争力评价体系,并用此方法对青县的的电子机箱产业进行了实证分析.研究结果表明青县电子机箱行业的核心竞争力不强,其中资源整合与控制能力,技术创新能力、组织管理能力、人力资源竞争力和企业文化聚合力较弱、在此基础上提出了相应的政策建议.     

二氧化硅负载支链有机膦的合成及其在二氧化碳催化氢化反应中的催化性能

以改性二氧化硅为核,利用发散法合成出二氧化硅负载的1～6代端胺基树枝状高分子(SiO2-PAMAM),样品经FT-IR,TG和端胺基分析表征.利用功能化载体表面的氨基与[Ph2P(CH2OH)2]+Cl-发生反应,合成出SiO2-PAMAM负载的有机膦(SiO2-PAMAM-PPh2),与三氯化钌复配成催化体系,考察了其对吗啉存在下的二氧化碳催化氢化反应的催化性能,该催化体系的催化活性(TOF)可达4 195.     

模糊综合评价方法在桥型多方案选择中的应用

为了解决现阶段桥型多方案选择中过多依赖设计者经验,而不可避免的带来主观性与片面性的问题.针对桥型方案选择的多因素与模糊性特征,提出了模糊综合评价方法在桥型多方案选择中的应用,确定了影响桥梁选型的指标体系,介绍了该方法的应用模型与步骤,并结合实例详细介绍了这种方法的应用过程.结果验证了这一方法的简明性和实用性.有利于减少桥梁型式选择的失误,提高其客观性与合理性,以得出最佳方案.     

无烟煤熔融盐催化气化反应特性研究

根据煤催化气化原理及熔融盐特性,设计了一套小型熔融盐催化煤气化实验装置。针对无烟煤燃烧特性差的特点,在实验中研究了温度和二氧化碳流量对气化结果的影响,并对影响机理进行分析。     

水电站月度调度函数的模型制定与模拟结果评价

基于统计学中多元逐步回归原理建立了多年调节水电站分月调度函数模型,并根据水电站优化调度特征确定待选自变量,用以指导电站实际优化调度运行。在考虑电站自身各约束及综合利用要求的前提下,进一步采用程序设计模拟调度函数指导水电站长系列调度运行,通过对模拟结果的全面评价,证实所建立的调度函数具有良好的指导意义和实用价值。     

互联电力系统未知机理低频振荡分析

近年来,我国互联电力系统多次发生低频振荡。针对南方互联电网"5.13"功率振荡,首先采用特征值分析法详细分析南方互联电网低频振荡特性,得出主要振荡模式以及发电机组参与因子和模态分布图。其次利用仿真软件PSS/E,对强相关机组的切机、三相短路故障以及原动机周期扰动分别进行时域仿真,并与实际振荡曲线进行对比。结果表明,南方电网此次功率振荡不是因为强相关机组电气侧故障,采用负阻尼机理也不能很好地解释,其产生原因可能是发电机组受原动机周期扰动有关。     

基于单片机的病房无线呼叫系统设计

为解决传统病房有线呼叫系统存在的布线复杂、易出故障、维修不便、不能在现有床位基础上及时增加新床位信息等问题,提出了无线呼叫系统设计。采用STC89C52系列单片机作为主控芯片,nRF905作为无线收发的核心芯片,并配以相应的LCD显示屏和声光报警器,设计出了无线病房呼叫系统。结果表明,该系统可靠传输距离达90 m以上,具有一定的抗干扰性,且可以临时方便增加床位显示信息,能够满足医院的临时实际需求。该系统性能稳定,操作简便,可以有效代替传统有线呼叫系统。     

Research on technology of desktop virtualization based on SPICE protocol and its improvement solutions

Increasingly mature cloud computing technology promotes virtual desktop technology, which can solve many problems existing in traditional computing models. However, virtual desktop solutions introduce the thorny problem of how to deliver a real desktop experience to users, as if they are using it locally, especially when playing video. The SPICE （simple protocol for independent computing environments） virtual desktop solution provides several image compression algorithms to address this problem with the purpose of making virtual desktops as real as possible. Although different compression algorithms can contribute their own abilities to different images to a large extent, switching between them is a big problem that consumes a large amount of resources to detect the different type of image and also causes jitter of the virtual desktop. This paper proposes a new solution, called SPICEx, using the JPEG2000 compression algorithm with dynamic compression ratios to solve the problem and finally validates that the performance is better than that of SPICE. With better quality of user experience and also reducing bandwidth consumption, SPICEx solution is meaningful in virtual desktop fields and can be widely used.     

Experimental study on temperature stress calculation and temperature control optimization of concrete based on early age parameters

Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves：convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.     

基于L1输出反馈自适应方法的火箭姿态控制

针对运载火箭刚—弹耦合动力学模型,开展了基于L1输出反馈自适应方法的火箭姿态控制器设计.考虑到L1控制器低通滤波器环节可能在一定程度上减少弹性影响,分析了火箭不同低频模态对控制系统的影响情况.由于低通滤波器带宽与系统带宽存在相互制约关系,当无法通过低通滤波器设计消除低阶弹性影响时,结合校正网络设计L1输出反馈控制器.仿真结果表明,上述设计思路能够应对火箭低阶弹性问题,所设计的控制器控制效果良好,且在弹性频率变化时系统依然具有良好的暂态和稳态性能.