Comparison of mass transfer efficiency in horizontal rotating packed beds and rotating biological contactors

In this study, the mass transfer efficiencies of a novel horizontal rotating packed (h‐RPB) bed and the conventional disc‐type rotating biological contactor (RBC) were studied at four speeds and seven submergences. Pall rings of two different sizes (25, 38 mm), superintalox saddles and a wiremesh spiral bundle were used as packings in the h‐RPB. Volumetric gas–liquid mass transfer coefficients were determined by unsteady state absorption of atmospheric oxygen in de‐aerated water. Power consumption per unit liquid volume has been found for all geometries tested. The oxygen transfer efficiency values for the h‐RPB were found to be 2–5 kg kWh^?1 and for the disc RBC were found to be 1–2 kg kWh^?1. The performance of the h‐RPB was also compared with other gas–liquid contactors such as surface aerators. The study proves that the h‐RPB is a energy efficient alternative to conventional contactors. Copyright © 2005 Society of Chemical Industry     

OCS表面活性剂工业品的界面活性及驱油效率

针对现有三元复合驱油体系化学剂费用投入大,经济效益差的缺点,利用廉价的大庆减压渣油为原料合成了驱油用表面活性剂OCS.测试结果表明,OCS表面活性剂工业品具有优异的降低原油-地层水界面张力的能力,能在较宽的碱浓度和表面活性剂浓度范围内使不同大庆采油厂原油的油-水界面张力降至10^-3mN/m.在无碱条件下,对于大港油田枣园1256断块原油,当OCS活性剂质量分数达到0.2%时,油-水界面张力即可降至10^-3mN/m.大庆原油的平面模型驱油试验表明,OCS表面活性剂、碱和聚合物三元复合体系（ASP）的驱油效率比水驱提高20%以上.     

镁法海绵钛生产工艺中大型无隔板镁电解槽的节能实践

以镁法海绵钛生产工艺中大型无隔板镁电解槽的实际节能情况为例，探讨了在镁电解生产中的非生产耗电、生产耗电、漏电等因素造成的能量浪费，阐述了生产中粗镁直流电耗、电流效率、工作电压3者之间的关系，指出了影响电解槽工作电压的有关因素及降低电解槽工作电压的途径。     

LASER ENHANCED ELECTROCHEMICAL MACHINING PROCESS

An experimental apparatus was designed and built for the hybrid process of laser enhanced electrochemical machining (ECM). Comparison experiments had been done between solely ECM and laser enhanced ECM. The machining performance of hybrid process was investigated and compared with solely ECM. The principle of the hybrid process was exposed by analyzing the microstructure of machining surface. The results show that the hybrid process has advantages in machining accuracy, surface quality, and machining efficiency.     

调幅系数为任意值的调幅波研究

本文讨论了调幅系数为任意值的调幅波，给出了它的表达式，频谱与调幅系数，调制效率和信噪比增益的计算公式。     

烧结机蒸汽系统新老余热管网并网改造

针对烧结机新老蒸汽系统各自独立，使用效率低，不能充分发挥效能的状态，提出了蒸汽系统新老余热管网并网改造，经过一年多的运行，取得了显著的效果。     

新增探明储量技术采收率主控因素

在申报探明可采储量时，关键是采收率的取值，由于油藏处在勘探评价或开发初期，受资料所限，采收率只能是应用经验公式法、经验取值法、类比法和数值模拟法求取，然后综合确定一个值，在求取过程中关键是明确此阶段采收率的主控因素，从而相对准确地求取采收率值。通过分析，明确了探明储量技术采收率的主控因素为油藏驱动类型、储层渗透率、储层非均质性、原油地下粘度及井网密度，为此阶段科学评价采收率奠定了基础。     

旱地农业降水高效利用技术应用研究

旱地农业建设必须借助科技进步，提高天然降水的有效利用，具体应围绕提高降水利用率和水分利用效率，在积极应用传统旱地农业技术的基础上，加强高新技术和常规技术相结合，重点推广雨水集蓄利用技术。     

基于CFD分析的轴流式螺旋叶轮设计

针对一种井下马达的轴流式螺旋叶轮进行了理论计算，并利用CFD方法对其进行了紊流数值模拟。根据CFD分析结果对理论计算的结果进行了修正，并通过比较同一工况下不同螺旋角叶片的水力效率，得出了在满足设计要求条件下的最优螺旋角。通过试验，验证了CFD分析在计算和优化设计此种轴流式螺旋叶轮的有效性，并具有指导意义。     

Fixed collision rate back-off scheme for collision resolution in wireless networks

This investigation proposes a fixed collision rate (FCR) back-off algorithm for wireless networks. The proposed scheme takes advantage of the central unit (CU) in a wireless network to broadcast a common back-off window size to all the users, significantly alleviating the unfairness of bandwidth utilization in conventional binary exponential back-off (BEB) algorithms. It is shown that, when maximum throughput is achieved, collision rate is almost a constant for any traffic load. In the operation of the FCR, the CU dynamically adjusts the back-off window size to keep the collision rate at a constant level for maximum throughput. Simulation results demonstrate that the unfairness of bandwidth utilization in the BEB is significantly lessened and the throughput can be maintained at e^-1≈0.368 when the number of users approaches infinity. The capture effect even further improves system performance.