Characteristic modes and flow structure of non-premixed flame in humid-air combustion

An experimental study has been performed in order to determine the effect of humidity on the flow field and the flame stability limit in turbulent non-premixed flame. Two-dimensional Particle Image Velocimetry (PIV) measurements were made to quantify the velocity field, with and without steam injected. The results indicate the addition of steam decreases the recirculation flow and reduces the distance between the forward and aft stagnation points. The detailed stabilization regimes show that the critical fuel-to-air velocity ratios of the central fuel penetration in the humid air case are 16% to 22% lower, and the partially quenching limits are at least 25% lower. The decreased penetration limit is due to a reduction in momentum of the humid air. An analysis of flamelet concepts reveals that increased chemical reaction time leads to lower partially quenching limits in the humid air combustion.     

C5石油树脂在橡胶中应用的探讨

将Ｃ５石油树脂应用于丁苯橡胶（ＳＢＲ）和天然橡胶（ＮＲ）／顺丁橡胶（ＢＲ）并用胶中进行了全面性能试验。结果表明：国产和进口树脂的各项性能基本一致；适量加入树脂对胶料物理性能无明显影响；Ｃ５树脂对胶料具有明显增粘效果，是一种值得大力推广的产品。     

卤水泵机械密封动环材料的研究

针对卤水泵机械密封中由于密封材料腐蚀的难题，研究开发了新型动环材料WC-NiP合金，考察了新材料在卤水中的腐蚀磨损性能。得出WC-NiP合金是卤水泵中作为机械密封动环材料的首选材料。     

Modeling of photocatalytic oxidation of VOCs in a packed bed reactor under continuous and discontinuous illuminations

In this paper, a mathematical model is presented to describe the photocatalytic degradation of VOCs in a packed bed reactor. Here, the adsorption of VOCs on the wall of the reactor is taken into account and the diffusion of VOCs in the axial direction is neglected. First-order kinetics is used to describe the photocatalytic oxidation of VOCs. The analytical solution of the present model is obtained by traveling wave method. The solution shows that the reactor performance is totally dependent on the inlet concentration of VOCs when the time is large enough. The present model is validated through the experimental result of the photocatalytic oxidation of trichloroethylene in a packed bed and the predicted results accord well with the experimental data. The influence of flow rate and inlet concentration on the performance of the reactor is discussed in detail. High flow rate offers high reaction rate and low conversion efficiency. The different inlet conditions and different reaction patterns are also investigated. The model would be useful to estimate the rate constant and help to the design of the reactor.     

Solvent fractionation of petroleum pitch for mesophase formation

Petroleum pitch (Ashland A240) has been subjected to thermal treatment and solvent fractionation to produce refined pitches to be evaluated as impregnants for C-C composites. The solvent fractions were obtained by sequential Soxhlet extraction with solvents such as hexane, benzene, and pyridine. Thermal treatment to 408 °C produced a mesophase pitch (≈50% mesophase); an appreciable portion of the mesophase was soluble in strong solvents. There were substantial differences in chemical composition and in pyrolysis behaviour of the fractions. As the depth of fraction increased, the pyrolysis yield and bloating increased, and the microstructure of the coke became finer until glassy microconstituents were formed in the deepest fractions.     

Effect of the geometry and pattern of the flow channel on the performance of polymer electrolyte membrane fuel cell

This research focuses on the effect of the geometry and patterns of the gas flow channel on the PEM fuel cell performance. Simulation was conducted and the results were verified by experiments. Three-dimensional, single phase, compressible and isothermal models of 5 cm² electrodes, anode and cathode, were developed and studied by utilizing a commercial Computational Fluid Dynamics (CFD) software, FLUENT 4.5. Two types of gas flow channel were investigated: conventional and interdigitated. The results showed that the flow channel pattern does not have a significant effect on the anode cell performance, whereas it has a strong effect/influence on the cathode cell performance. The interdigitated design provides a higher limiting current density and cell performance than the conventional design on the cathode side. Moreover, the cell performance does not depend on the inlet and outlet channel widths. On the contrary, for the interdigitated design, it was influenced by the shoulder width. Finally, experiments were conducted to validate the simulation results.     

计算机网络安全漏洞及解决方案初探

随着Computer Science和IT技术的迅速发展,计算机及网络技术已经逐步渗透进入人们的日常生活,但是目前由于网络具有的开放性和共享性,也导致了木马、黑客、计算机病毒等恶意程序的入侵,给计算机安全甚至计算机使用者的人身安全、财产安全都带来了极大地威胁,因此应对计算机网络安全漏洞势在必行.本文就目前计算机网络安全问题进行了分类并分析了其成因,还探讨了一些针对计算机网络安全问题的解决方案,为大家提供一定的借鉴意义.     

聚磷酸铵合成工艺条件研究

在常压条件下研究以湿法磷酸生产的磷酸二氢铵和尿素为原料生产聚磷酸铵的合成工艺条件，得到较温和的合成低聚合度聚磷酸铵的工艺参数。通过正交试验对聚磷酸铵的聚合条件进行了优化，得到了最佳工艺条件：反应温度160℃，反应时间1．5h，原料配比（磷酸二氢铵与尿素物质的量比）为1：1．1。在最佳工艺条件下合成的聚磷酸铵的聚合度达到了34，氨氮含量和有效磷含量分别为16．65％和70．20％（均为质量分数）。     

Moisture absorption behavior of rubber‐modified epoxy resins

The moisture absorption behavior of diglycidyl ether of bisphenol A/ethylene diamine resins incorporating a carboxy‐terminated butadiene–acrylonitrile rubber was investigated and associated with their morphology of phase separation. Although the diffusion coefficient of moisture was increased with the rubber content, its activation energy and free volume for moisture diffusion were barely changed until phase inversion occurred. After phase inversion, the free volume was significantly increased, and the activation energy decreased. In addition, the moisture absorption also reduced the β‐transition temperature of the resins and slightly increased the glass‐transition temperature before phase inversion. However, the reverse was found after phase inversion. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3718–3724, 2002     

超声波测距的模糊控制泊车系统模型设计

设计了一种基于超声波测距的自动泊车系统模型。首先对小车运动模型进行分析,结合实际设计垂直、平行、斜行三种泊车模糊控制器,并且在Matlab的Simulink中分别进行仿真验证。采用超声波测距技术、视频采集技术等来获取周围环境数据,按照实际车辆和车库的大小,通过等比例缩放设计小车模型和车库模型,并把验证通过的模糊控制器转换为C代码,嵌入到飞思卡尔K60主控制板中进行自动泊车可行性测试。经测试,当模型车的航向角在-32°~+32°范围内时,实现了模型车在0.92倍标准大小模型车库内的自主泊车。