Chemistry and Physics of Alkali Metals on MoS2 Surfaces

The interaction of alkali metal with surfaces has been of great interest to the community of catalysis since alkali metal can play an important role as a promoter. On alkali-doped MoS₂, such a promotion effect of alkali metal has been exemplified in the direct synthesis of linear alcohols from CO and H₂, where the alkali-doping switches the catalyst selectivity from methanation to alcohol synthesis. This paper reviews recent high-resolution X-ray photoelectron spectroscopy experiments that have provided direct observation of electron transfer from alkali metals to a model single crystal MoS₂ and the capture of the supra-valence electrons in the subsequent oxidation reactions.     

Recursive solution of inverse natural convection problems by means of mode reduction

 A recursive method based on the Kalman filtering is developed to solve inverse natural convection problems of estimating the unsteady nonuniform wall heat flux from temperature measurements in the flow. By employing the Karhunen–Loève Galerkin procedure that reduces the Boussinesq equation to a small set of ordinary differential equations, the computational difficulties associated with the Kalman filtering for the partial differential equations are overcome. The present method is assessed through several numerical experiments, and is found to yield satisfactory results. Received 20 January 2001 / Accepted 31 May 2001     

钼还原过程相变化研究

采用钼酸铵直接氢还原及钼酸铵先焙解然后再分段氢还原两种不同的还原方法进行了钼粉还原。通过Ｘ射线衍射方法分析了两种工艺还原过程中的反应序列及相变化规律，并讨论了不稳定相Ｍｏ４Ｏ１１对于钼粉还原过程的影响。     

A novel laboratory bench for practical evaluation of catalysts useful for simultaneous conversion of NOx and soot in diesel exhaust

This study deals with the development of a laboratory bench for the practical evaluation of catalysts that are useful for the direct conversion of NO_x and soot in the exhaust of diesel engines. The employed model exhaust is generated by using a diffusion burner with additionally dosing some gaseous components to the burner gas to obtain a realistic feed composition. The produced soot is extensively characterized by employing thermogravimetry, transmission electron microscopy, N₂ physisorption and temperature programmed techniques. The results of the different characterization methods show that the present soot is suitable for the intended catalytic investigations. The simultaneous conversion of NO_x and soot is examined like in practice, i.e. the soot is separated from the tail gas by a diesel particulate filter (DPF) that is coated with the catalyst. The deposited soot is then catalytically converted by NO_x and O₂ to form N₂ and CO₂. The conversions of NO_x and soot are measured by exclusively applying gas analysers, whereby a special experimental procedure is developed to determine the soot removal. Hence, additional soot related analytics are not required. To show the suitability of the constructed bench a Pt/Fe₂O₃/β-zeolite sample is taken as test catalyst that is reported to be very active in NO_x/soot reaction. The measurements performed with and without catalyst clearly show the effect of the used sample in simultaneous NO_x/soot conversion. We therefore consider the constructed laboratory bench to be a useful tool for testing and ranking catalytic materials.     

活性污泥生物相对污水处理运行的指导作用

污水处理系统处理效果的好坏都与污水处理系统中组成活性污泥的微生物种类、数量及其代谢活力有关,本文从活性污泥结构、微生物种类、数量及活性等方面分析了污泥生物相与运行状态的相互关系.说明了可通过对污水处理系统的生物相观察了解处理效果及运行状况,也可通过对污泥生物相观察发现处理系统环境的变化,及时调整运行环境,预防污水处理系统的运行中的异常情况发生.     

Reducing Average and Peak Test Power Through Scan Chain Modification

Parallel test application helps reduce the otherwise considerable test times in SOCs; yet its applicability is limited by average and peak power considerations. The typical test vector loading techniques result in frequent transitions in the scan chain, which in turn reflect into significant levels of circuit switching unnecessarily. Judicious utilization of logic in the scan chain can help reduce transitions while loading the test vector needed. The transitions embedded in both test stimuli and the responses are handled through scan chain modifications consisting of logic gate insertion between scan cells as well as inversion of capture paths. No performance degradation ensues as these modifications have no impact on functional execution. To reduce average and peak power, we herein propose computationally efficient schemes that identify the location and the type of logic to be inserted. The experimental results confirm the significant reductions in test power possible under the proposed scheme.     

大港油田官109-1断块稠油油藏碱/表面活性剂吞吐采油技术

大港油田官109-1断块稠油油藏的油井由于井筒、近井地带发生原油有机沉积,储层原油流动性差,采用多种方法都不能正常生产。为此研制了一种碱性解堵液,用于油井化学吞吐。该解堵液为复配碱和抗硬剂等添加剂的10%两性木质素表面活性剂溶液,能使玻璃片表面由亲油变强亲水,在石英上的接触角为6°(稀释至1/2和1/4浓度时为11°和12°),与羊大站原油间的界面张力为1.75×10-3~3.18×10-3mN/m。该解堵液与黏度1~50 Pa.s的不同区块稠油按体积比1∶1混合形成的乳状液,60℃、175 s-1黏度为2~6 mPa.s,在配液水矿化度高达6000mg/L以上或钙镁离子浓度高达250 mg/L时,该解堵液仍能保持对稠油的乳化降黏能力。该解堵液从实验岩心中驱出的原油量比地层水多75%,驱出液为乳状液。通过一个井例介绍了化学吞吐工艺:先用一种降黏解堵液对油井进行预处理,清洗油管、炮眼及近井地带,再注入碱性解堵液(该井例中为500 m3),注入时间约15小时,然后开井生产。2000年2月至2002年6月在16口新投产井实施化学吞吐(第一轮次),15口井有效,其中2口井先后转注水,其余13口井到2005年底仍继续产油。图1表6参5。     

Manipulating Deformable Linear Objects: Fuzzy-Based Active Vibration Damping Skill

Human can handle a deformable object and damp its vibration with recognized skill. However, for an industrial robot, handling a deformable object with acute vibration is often a difficult task. This paper addresses the problem of active damping skill for handling deformable linear objects (DLOs) by using a strategy inspired from human manipulation skills. The strategy is illustrated by several rules, which are explained by a fuzzy and a P controller. A proportional-integral-derivative (PID) controller is also employed to explain the rules as a comparison. The interpretations from controllers are translated into high level commands in a robotic language V+. A standard industrial robot with a force/torque sensor mounted on the wrist was employed to demonstrate the skill. Experimental results showed the fuzzy based damping skill is quite effective and stable even without any previous acknowledge of the deformable linear objects.Category (5)     

渭河流域水利水保措施减水减沙效益初步分析

截止1989年底,渭河流域共有水库361座,塘坝2666座,引水有效灌溉面积40.4万公顷,治理总面积8136km~2,治理度17.1％。以1970年为效益计算起始年,并将全流域划分为18个片,分别采用水文法和水保法计算1970～1989年间各项水利水保措施减水减沙量及综合减水减沙效益。水文法算得的综合减水效益为24.1％,减沙效益为30.6％;水保法算得的结果相应为29.9％和30.8％,两者相近。     

Efficient model reduction in non-linear dynamics using the Karhunen-Loève expansion and dual-weighted-residual methods

 We look at the task of computing the time-evolution of a non-linear system for a long time, in our case under random external influences. Our specific example is the fatigue evaluation of a wind turbine. To facilitate such a computation, we look at a reduction of the computational effort by projecting everything on a low-dimensional basis. In this case we take the Karhunen-Loève basis generated from running the model a little while under the random loading. It is important that the error which is caused by this reduction process can be controlled. We estimate the error by dual or adjoint methods. This in turn allows the process of model reduction to be performed adaptively. Dedicated to the memory of Prof. Mike Crisfield, for his cheerfulness and cooperation as a colleague and friend over many years.