我国工程机械现状及今后发展趋势

中国的工程机械行业建立于1961年。改革开放以后，由于国内对工程机械的需求量大，自1978年开始至20世纪末共引进近200项技术．发展了近500个新产品。使我国的工程机械迈上了一个新的台阶，当年引进的产品目前已成为我国工程机械的主导产品。     

改性生物质作为型煤黏结剂的研究

探讨了用NaOH改性生物质秸秆作为型煤黏结剂的可行性,考察了NaOH溶液浓度对生物质改性的影响以及生物质添加量、无机物(MgO和MgCl2)添加量对型煤机械强度、防水性能和着火温度的影响。研究结果表明,NaOH改性液的质量分数为1.0%~2.0%时,制得的生物质型煤有较高的机械强度;生物质添加量在2%~20%时,随生物质添加量的增加,机械强度增加,着火温度降低,但防水性较差;而在生物质型煤中加入适量无机黏结剂后,型煤有很高的浸水强度,表现出优越的防水性能。     

PTA压力离心机转子的改造

介绍了PTA压力离心机的主要性能参数、工作原理、分离效果的影响因素。为了增大沉渣在过渡区及脱水区滞留的时问，同时为达到在过渡区及脱水区对沉渣加入纯净水进行再冲洗的目的，对螺旋送料转子、挡液环、进料管进行了改造。改造后，沉渣在脱水区的停留时间由0．44a增至0．72s，2．5～3t／h的冲洗水对脱水区的沉渣进行冲洗效果较好。产品中的杂质质量分数较改造前减少15％，产品优等品率提高到99％。     

On effective offloading services for resource-constrained mobile devices running heavier mobile internet applications

Rapid advances in wireless mobile network technologies and mobile handsets (MHs) facilitate ubiquitous infrastructure that can support a range of mobile services and applications in addition to conventional mobile Internet access. One recent trend is to effectively run desktop PC-oriented heavier applications on MHs. However, due to their miniature, portable size, MHs are resource-constrained and therefore, running these applications directly on an MH is not satisfactory given a user's expectations. To cope with this problem, this article proposes a novel offloading service that can seamlessly offload some of the tasks of a mobile application from an MH to nearby, resource-rich PCs (called surrogates). The system architecture and key components of the proposed offloading service are presented, prototyped, and evaluated. The results of experiments and simulations have demonstrated the effectiveness and efficiency of this offloading service for mobile applications.     

镁热还原K2ZrF6制备镁锆中间合金

在KCl、NaCl熔剂的保护下,液态Mg能够还原K2ZrF6.通过控制炉料配比、还原温度、还原时间,并用机械正反向交替搅拌,成功地解决了传统生产工艺中渣相与Mg-Zr中间合金难以分离、合金杂质含量偏高、合金成分偏析的难题,获得了高质量的Mg-Zr中间合金.     

An investigation into physicochemical characteristics of ash produced from combustion of oil palm biomass wastein a boiler

Ash derived from combustion of Malaysian oil palm biomass (empty fruit bunches consisting of fibers) was physically and chemically characterized in order to provide a comprehensive understanding of its specific properties in terms of toxicity, compositions and reusability. Principal analyses conducted include particle size distribution, scanning electron microscopy, elemental dispersive X-ray, elemental analysis, toxicity characteristic leaching procedure (TCLP) as well as thermogravimetric, X-ray diffractometry and Fourier-transform infrared analyses. TCLP result indicated that the oil palm ash (OPA) should not be classified as toxic wastes in terms of heavy metal leachability since leachable copper, cadmium, lead and nickel concentrations were detected below the stipulated leachability limits. It was determined that the OPA contained high amount of potassium as well as presence of silica which implied its suitability to be reused as crude fertilizer or cement replacement material.     

Effect of vibration condition and inter-particle frictions on the packing of uniform spheres

We present a numerical study of the packing of uniform spheres under three-dimensional vibration using the discrete element method (DEM), focusing on the effects of vibration condition (amplitude and frequency) and inter-particle frictions (sliding and rolling frictions). The results are analysed in terms of packing density, coordination number (CN), radial distribution function (RDF) and pore structure. It is shown that increasing either the vibration amplitude or frequency causes packing density to increase initially to a maximum and then decrease. Both vibration frequency and amplitude should be considered to characterize the effect of vibration process on packing structure. The sliding and rolling frictions between particles can decrease packing density since they dissipate energy, although the effect of rolling friction is less significant. In line with the change of packing density, microstructural properties such as CN, RDF and pore distribution also change: a looser packing often corresponds to smaller CN, less peaked RDF and larger but more widely distributed pores.     

基于Lab VIEW的小型汽油机磁电机点火提前角的测量

本文介绍了磁电机点火系统的点火提前角测量原理。对点火系统的点火信号和触发信号进行采集、调理，再用单片机进行处理，最后用LabVIEW进行点火提前角数据存储和显示。     

一台循环流化床锅炉U型二次分离的改进对过热器爆管的影响

文章通过对一台循环流化床锅炉U型二次分离装置的改进，减少了过热器爆管的介绍，给出了采用多次离心分离技术，改善和提高烟尘分离效率，从而改善过热器外部工作条件，达到减少爆管发生的措施，相应提出了一些有关的建议。