Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Ultrasonic Loop Airlift Reactor

The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the loop airlift reactor was studied. The gas holdup, liquid circulation velocity, mixing time and overall volumetric mass transfer coefficient were examined and compared, with and without ultrasonic wave in the reactor. The experimental results show that ultrasound has almost no notable effect on the gas holdup, but has a tendency to decrease gradually the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; and the effect on the mixing time is relatively complex. At low superficial gas velocity, the low powered ultrasound promotes the radial mixing of fluid; with the ultrasonic power increasing, ultrasonic vibration obstructs the axial mixing of fluid. Moreover, the effect of ultrasonic wave on the mixing time gradually decreases with the increase in the superficial gas velocity. Therefore there exists an optimal ultrasonic power for hydrodynamics and mass transfer. Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor.     

Synthesis and properties of poly(aryl ether sulfone ether ketone ketone) (PESEKK)

4,4′‐bis(Phenoxy)diphenyl sulfone (DPODPS) was synthesized by reaction of phenol with bis(4‐chlorophenyl) sulfone in tetramethylene sulfone in the presence of NaOH. Two poly(aryl ether sulfone ether ketone ketone)s (PESKKs) with high molecular weight were prepared by low temperature solution polycondensation of DPODPS and terephthaloyl chloride (TPC) or isophthaloyl chloride (IPC), respectively, in 1,2‐dichloroethane and in the presence of aluminum chloride (AlCl₃) and N‐methylpyrrolidone (NMP). The resulting polymers were characterized by various analytical techniques, such as FT‐IR, ¹H‐NMR, DSC, TG, and WAXD. The results show that the T_g and T_d of PESEKKs are much higher, but its T_m is lower than those of PEKK. The other results indicate that PESEKKs exhibit excellent thermostabilities at 300 ± 10°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 489–493, 2005     

用玻璃球负载纳米级SO4^2-／TiO2固体超强酸催化合成乙酸正丁酯

用玻璃球负载纳米级SO42-/TiO2固体超强酸催化合成乙酸正丁酯,对催化剂的制备条件和乙酸正丁酯的合成条件进行了研究。在最佳反应条件下,乙酸的转化率为99.3%,催化剂重复使用8次后乙酸的转化率仍高达92.3%。该催化剂选择性好,未发现有副产物生成,看来具有较好的应用前景。     

测井资料在井壁稳定性研究中的应用

井壁稳定性问题是石油钻井工业面临的一个重大课题。利用测井资料研究井壁稳定性是一种有效的方法。文章利用声波、密度测井资料计算了岩石力学参数、岩石强度参数，在此基础上进行了地应力计算、进而确定了地层破裂压力和坍塌压力，预测了安全钻井液密度范围，为钻井设计提供参考，并可指导安全钻井。通过新疆X 201井安全钻井液密度窗口的测井预测值与实钻钻井液密度对比分析，证明利用测井资料评价井壁稳定性的可行性和准确性，具有工程应用价值。     

Phase behavior of ternary polymer blends with favorable interactions

Atactic poly(methyl methacrylate) (aPMMA) and poly(vinyl pyrrolidone) (PVP) with a weight‐average molecular weight of 360,000 g/mol were found to be immiscible on the basis of preliminary studies. Poly(styrene‐co‐vinyl phenol) (MPS) with a certain concentration of vinyl phenol groups is known to be miscible with both aPMMA and PVP. Is it possible to homogenize an immiscible aPMMA/PVP pair by the addition of MPS? For this question to be answered, a ternary blend consisting of aPMMA, PVP, and MPS was prepared and measured calorimetrically. The role of MPS between aPMMA and PVP and the effects of different concentrations of vinyl phenol groups on the miscibility of the ternary blends were investigated. According to experimental results, increasing the vinyl phenol contents of MPS has an adverse effect on the miscibility of the ternary blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2064–2070, 2005     

Structure and properties of nitrile rubber (NBR)–clay nanocomposites by co‐coagulating NBR latex and clay aqueous suspension

Nitrile rubber (NBR)–clay nanocomposites were prepared by co‐coagulating the NBR latex and clay aqueous suspension. Transmission electron microscopy showed that the silicate layers of clay were dispersed in the NBR matrix at the nano level and had a planar orientation. X‐ray diffraction indicated that there were some nonexfoliated silicate layers in the NBR–clay nanocomposites. Stress–strain curves showed that the silicate layers generated evident reinforcement, modulus, and tensile strength of the NBR–clay nanocomposites, which were significantly improved with an increase in the amount of clay, and strain‐at‐break was higher than that of the gum NBR vulcanizate when the amount of clay was more than 5 phr. The NBR–clay nanocomposites exhibited an excellent gas barrier property; the reduction in gas permeability in the NBR–clay nanocomposites can be described by Nielsen's model. Compared with gum NBR vulcanizate, the oxygen index of the NBR–clay nanocomposites increased slightly. The feasibility of controlling rubber flammability via the nanocomposite approach needs to be evaluated further. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3855–3858, 2003     

企业科技人员要重视科技论文的写作

科技论文是进行科学技术研究工作的一个重要手段,是科学技术研究工作的一个重要组成部分,是科学技术研究工作最后的和必不可少的环节,也是科学技术研究工作最终完成的标志。科技论文是科研成果的表现形式,发表科技论文的数量和质量是衡量一个科技人员学识水平、业务能力和业务成绩的重要指标,因此,企业科技人员一定要重视科技论文的写作。     

基于ZigBee的PLC无线数据采集系统设计

为解决某些特定工业区域数据采集的问题,提出了基于ZigBee协议,通过星型网络实现主从节点之间数据采集和传输的方案。本设计以射频芯片CC2430为核心设计了基于ZigBee无线传输协议的PLC数据采集系统,实现了包括区域内的温度数据检测、基于ZigBee的无线的数据传输、RS232协议与RS422和RS485协议之间的转换、PLC与CC2430和PC机之间数据交互以及通过上位组态软件MCGS对温度数据监控等诸多功能。经实验调试,该采集系统达到了设计的要求,效果良好,对实现ZigBee技术在工业领域的应用具有实际意义。     

节约型高校建设对策探析

讨论节约型高校建设的现实价值以及节约型高校建设的问题和成因,从思想政治教育、科学管理、科研创新、典型示范的角度出发,论述了加强节约型高校建设的对策。     

重庆市高校学报与学科建设相互作用的调查研究

高校学报与学科建设相互作用、相互促进,关系密切.以学报内稿为研究对象,通过对学报的作者队伍、学科方向、学术成果的调查,呈现重庆市高校学报与学科建设相互作用的现状,并针对存在的问题,从稿源保证、作者队伍建设、学术成果等三方面提出了对策.