A Method for State Diagnosis of Grounding Grid

This paper discuses the method with which the corrosion of the grounding grid can be diagnosed .A grounding grid can handled as a circuit network. With the application of circuit network graph theory and the fault diagnosis theory of analog circuit and optimization, the fault diagnosis equations can be set up. This equations is figured out by Matlab, and the corrosion status of the grounding grid can be deduced from the result.     

LABORATORY INVESTIGATION OF ESSENTIAL CHARACTERISTICS PARAMETERS FOR THE INDUCED-NOZZLE DEVICE

The standoff of a submerged jet is smaller than a non-submerged jet in general. In order to increase the standoff of a submerged jet, the induced-nozzle device is presented with its inducing mechanism analysed in this paper. Under the various inducing medium, the effect of the ratio d2/d1 upon the device's properties is measured. Some reasonable parameters are given. When d2/d1=2.0, approximate straight region of the curve of the jet center line stagnation pressure varying with the standoff is L/d1= l0~12 for inducing air. The induced-nozzle device is compared with the conventional nozzle for shotting some samples. Several applied possibilities of the device are discussed.     

发动机用平板型空滤器流动阻力特性分析和改进

为减小平板型空滤器流动阻力以增大进气量,对平板型空滤器流动阻力特性开展了实验研究,获得了空滤器流动阻力随流量变化的规律和阻力构成成分。阻力随流量的增大而加速增大,滤芯阻力约占整个空滤器阻力的一半,入口流量为120 m 3/h时,总阻力为915.3 Pa,滤芯阻力为426.4 Pa。在实验获得滤芯阻力参数的基础上,提出采用多孔介质跃升模型对平板型空滤器内部流场开展三维数值仿真分析,结果表明,仿真结果与实验结果比较吻合,最大误差为5.67%。滤芯阻力同样约占整个阻力的一半,另一半阻力主要为出口处阻力,其余壁面阻力约占15%。最后,在实验和仿真分析的基础上,提出了改进模型并进行了仿真分析。结果表明,改进模型阻力有较大程度的下降,入口流量为120 m 3/h时,总阻力为588.2 Pa,较原始模型下降了32.2%;增大空滤器流通横截面积是减小阻力以增大进气量的有效手段,改进空滤器壁面的平滑性是补充措施。     

THE X-RAY DIFRACTION ANALYSIS FOR COLOURED CEMENT AND ITS HYDRATE MINERAL

This paper studies the nineral composition,mineral phase transformation mech-anism and properties of hydration and hardening of the coloured cement by using x-ray diffractionanalysis and the x-ray diffraction analysis reliability is checked by using scanning electron mi-croscopy and infrared spectral analysis and other physical and chemical analysis methods.     

空蚀、磨损及其联合作用研究进展

空蚀、磨损及两者联合作用是目前流体机械破坏的重要原因，通过实验及数值模拟研究得到空蚀、磨损及两者联合作用的机理是发展流体机械优化设计方法、提高流体机械抵抗空蚀磨损破坏能力的基础．由于影响空蚀、磨损及两者联合作用行为的因素既有速度、压力等流场参数，又有沙粒和材料特性等，近年来此领域的研究在空蚀磨损及联合作用机理、各因素间的相互影响及高抗破坏材料等方面展开．基于此，本文选择性的分析了相关的报道文献，为进一步开展流体机械过流表面快速破坏机理的研究提供理论支持．     

曲轴模拟分析和测试技术的研究进展

曲轴的动力学特性对内燃机噪声、振动以及粗糙刺耳的音质的研究至关重要，因此必须尽可能准确地认识其内在机理。在曲轴模拟分析和测试技术研究领域中出现了许多成果．本文对这些成果作了简要介绍和分析。     

斑玉蕈木质素降解酶高活性菌株的筛选和鉴定

以前期试验获得的4株斑玉蕈(Hypsizigus marmoreus)杂交菌株为试材,利用亮蓝-PDA平板显色试验、苯胺蓝-PDA平板脱色试验、体细胞不相容试验和ISSR分子标记技术,筛选斑玉蕈木质素降解酶高活性菌株,并鉴定其生物学和遗传学特性,以期丰富斑玉蕈优良品种.结果 表明:杂交菌株JZB2124031的木质素降解酶活性最高,亮蓝-PDA平板和苯胺蓝-PDA平板可分别出现明显的变色圈和脱色圈,与其它菌株均可产生拮抗反应.15条ISSR分子标记引物具有扩增稳定性,当相似系数为0.75时,22株菌可以划分为九大类,其中杂交菌株JZB2124031独为一类.综上,杂交菌株JZB2124031具有较高的木质素降解酶活性,与其它供试菌株的亲缘关系存在较大的差异.     

改性木质素对砖红壤磷素有效性的影响

磷肥施入砖土壤后，土壤速效磷随着时间的推移，呈现下降的趋势。利用改性木质素缓释磷铵，可以有效地络合土壤活性钵，降低其活性，从而阻止土壤速效磷被固定，使土壤磷素维持在较高的水平。土壤中交换性钙和交换性镁对土壤速效磷的影响不大。