Study on Test Methods for Flow Ability of Superfine Powder Extinguishing Agent

According to the physical and chemical characteristics of superfine powder extinguishing agent, three test methods are selected to measure the flow ability. By studying and comparing various test methods, apparatus and conditions, the optimum method and conditions to test flow property of superfine powder extinguishing agent are confirmed.     

“电气控制与可编程序控制器”重点课程建设实践与思考

讨论了两年来"电气控制与可编程序控制器"重点课程建设的有关情况,并结合课程建设实践与实际总结了课程教学特色.针对教学过程中存在的一些现实问题,提出了今后的工作方向.     

旋转硬化与统一硬化参量在修正剑桥模型中的应用

针对修正剑桥模型不能模拟土体剪胀性、应力路径转折时土体的应力应变特性以及应力引起的各向异性,将旋转运动硬化理论引入到修正剑桥模型中,给出了椭圆屈服面的旋转运动硬化机制,把等向硬化的修正剑桥模型扩展为旋转运动硬化模型.同时,为了能够反映砂土和超固结土的剪胀等本构特性,用统一硬化参量H代替修正剑桥模型中的等向硬化参数一塑性体积应变εpv,建立了一个新的基于旋转硬化与统一硬化参量的改进的修正剑桥模型.对修正剑桥模型、旋转运动硬化修正剑桥模型和新模型进行了定性对比,结果表明,新模型不但能够反映应力路径转折时土体的特性,也能描述土体的剪缩和剪胀.     

不同浓度氯化钙对非洲菊切花保鲜效果的研究

以非洲菊金黄色品种为供试材料,以浓度为0,0.1%,0.2%,0.3%,0.4%,0.5%的6个不同浓度CaCl<,2>作为保鲜液,通过外部形态观察和生理指标的测定,研究CaCl<,2>对非洲菊切花瓶插的保鲜效果,结果表明:CaCl<,2>可以一定程度上延缓非洲菊切花的衰老进程,延长瓶插寿命,各处理中0.5%的CaCl...     

Simulation and experiment of starting transient flow field of the hydrostatic bearing based on dynamic mesh method

A new method is developed to assess and analyze the dynamic performance of hydrostatic bear-ing oil film by using an amulets-layer dynamic mesh technique.It is implemented using C Language to compile the UDF program of a single oil film of the hydrostatic bearing.The effects of key lubrica-tion parameters of the hydrostatic bearing are evaluated and analyzed under various working condi-tions, i.e.under no-load, a load of 40t, a full load of 160t, and the rotation speed of 1r/min, 2r/min, 4r/min, 8r/min, 16r/min, 32r/min.The transient data of oil film bearing capacity under different load and rotation speed are acquired for a total of 18 working conditions during the oil film thickness changing.It allows the effective prediction of dynamic performance of large size hydrostatic bearing.Experiments on hydrostatic bearing oil film have been performed and the results were used to define the boundary conditions for the numerical simulations and validate the developed numerical model.The results showed that the oil film thickness became thinner with the increase of the operat-ing time of the hydrostatic bearing, both the oil film rigidity and the oil cavity pressure increased sig-nificantly, and the increase of the bearing capacity was inversely proportional to the cube of the change of the film thickness.Meanwhile, the effect of the load condition on carrying capacity of large size static bearing was more important than the speed condition.The error between the simula-tion value and the experimental value was 4 .25%.     

基于属性差异的产品缺陷数据关联规则模糊分类

针对工业生产过程中所产生的产品缺陷数据经过数据挖掘后关联规则存在不能有效组织的问题,提出一种基于项目属性差异的产品缺陷数据关联规则模糊分类方法,在建立模糊分类树的基础上,计算出关联规则间距离,并采用自组织神经网络聚类的方法对挖掘结果进行聚类分析。将该方法应用于冷轧带钢表面缺陷数据挖掘后处理,结果表明,该方法不仅能够得出两种不同属性项目间的关联性,还可以求出缺陷关联规则间的距离,距离越近的关联规则被聚为一类,其相似性越大。     

基于PSR模型的扎龙湿地生态承载力评价及预测

国家生态文明建设背景下,生态系统的承载力研究是探索可持续发展的新方向.该文选择扎龙湿地为研究区,以遥感影像、气象数据及社会经济数据为基础,建立压力-状态-响应(PSR)模型的指标体系,运用模糊综合评价算法对扎龙湿地的生态承载力进行评价;其次,借助障碍度模型,探讨扎龙湿地生态承载力演变的主要障碍因素;最后利用GM模型,预测其未来9年的生态承载力结果.结果表明：扎龙湿地生态承载系统一直处于中承载状态,但总体呈上升趋势;自然环境和地物覆盖2个因素层为制约生态承载力的主要因素.根据GM预测结果,未来9年,扎龙湿地生态承载力指数随年份增加而升高,生态状况持续向良性转化,符合可持续发展理念.     

Synthesis, characterization and magnetic properties of near monodisperse Fe3O4 sub-microspheres

Near monodisperse Fe3O4 sub-microspheres with an average diameter of 170 nm have been synthesized by a solvothermal reduction method, using K3[Fe（CN）6] as the raw material in the absence of any surfactants at 200~C℃ for 24 h. The products were detected by XRD, FESEM, TEM, and XPS. The investigation of the reaction parameters indicates that ethylene glycol plays a key role both as reducing agent and solvent. In addition, the reaction time and temperature also have important influences on the final product. The hysteresis loop of the near monodisperse Fe3O4 sub-microspheres shows a ferromagnetic behavior with saturation magnetization of 60.8 emu/g and coercivity of 124.7Oe.     

速生杨木改性材阻燃剂抗流失性的研究

在选用氮磷复合阻燃剂的前提条件下,考察低分子酚醛树脂对其在高湿条件下的固定作用,着重研究经过处理的速生杨木试件尺寸(横向)和质量变化情况。结果表明:经过阻燃处理后,阻燃剂溶液质量分数越大,试件的增重率越大,在后期测试过程中,其流失也愈严重。相同条件下(试件增重率相同时),所用的酚醛树脂（PF）质量分数越大,对阻燃剂的抗流失性改善效果越好。质量分数为25％的PF对降低氮磷无机复合阻燃剂流失率的效果最好。通过对比分析,PF对所选用的无机阻燃剂具有固定作用。     

NS2网络仿真技术及其在网络拥塞控制中的应用

介绍了NS2网络仿真技术的体系结构,分析了利用NS2进行网络仿真的实现过程,详细介绍了NS2在网络拥塞控制中的应用,并进行了仿真与性能分析,为进一步有效实施网络拥塞控制提供了可靠途径．