Numerical simulation of the mechanism of atypical dynamic phenomena in mines

An atypical dynamic phenomenon of mines, including its action forms and definition, were put forward, based on the mining accident at the Furong Mining Group Company in Sichuan, P. R. China. The mechanism of the atypical dynamic phenomenon was revealed by analyzing rock stress distribution, calculating the first and cycle broken distance of each thick and hard roof, and analyzing the balance structure of broken rock based on the three dimensional finite element software. The first stratum of the bent, sunken, aged strip was influenced by the geological conformation and the coal mining activity. This created the first break of the key stratum and led to the atypical dynamic phenomenon. We show that the key factors affecting the phenomena are the roof and floor structures, surrounding rock, and initial stress and rock burst tendency of the key stratum.     

Simulation analysis of piston slap of internal combustion engine

A finite element model of a piston and a block surface was established. After boundary and work conditions were applied, an initial transient analysis of the model was carried out. The simulation result of vibration acceleration on the block surface conformed well with the experiment, thus validating the model. Based on the model, the motion law of pistons in blocks was studied. The variation trend of the piston slap force, piston clearance on the piston slap force, and the effect of piston pin offset on the piston slap force at different crankshaft speeds were analyzed. Results show that suitable piston pin offset and smaller piston clearance reduce the piston slap force quite well; and the contribution of the piston force at the point when gas breaks out is dominant at low speed, which is not obvious at high speed. The findings provide evidence for the performance improvement of internal combustion engine development.      

A parallel cluster algorithm for self adaptive particle swarm optimization

Full scale data mining, such as in cluster problems, requires large numbers of computations. A parallel cluster algorithm for self adaptive particle swarm optimization was proposed to deal with this problem. The proposed parallel particle swarm optimization algorithm reduced the impact of the initial conditions via parallel searches of the globally best position amongst a varied population. Task parallelization and partially asynchronous communication of the algorithm were employed to decrease computing time. Furthermore, if combined with the characteristics of self adaptive and dynamical optimization parameters of the parallel particle swarm algorithm, the problems of particle mobility loss and the end of evolution could be dealt with successfully. When modified thusly, the algorithm maintains individual diversity and restrains degeneration. The simulation experiments indicate the algorithm helps increase computing speed and improve cluster quality.     

水稻白叶枯病菌hrcU基因缺失突变体构建及功能研究

通过基因敲除方式,构建了水稻白叶枯病菌hrcU基因的缺失突变体.突变体丧失了在水稻上的致病性和在非寄主植物上的过敏反应.携带hrcU基因的黏粒完全互补了hrcU突变菌株的表型,互补菌在水稻组织中的生长能力也与野生型菌株相当.免疫杂交结果显示,hrcU基因突变后,水稻白叶枯病菌的Harpin蛋白Hpa1不能从细胞内分泌到胞外.这些结果表明,水稻白叶枯病菌hrcU基因的主要功能是形成Ⅲ型分泌系统,将效应分子分泌到病原细菌胞外,从而决定了在非寄主上的过敏反应和在水稻上的致病性.     

盐碱地春播玉米栽培技术

近年来,宁河县春季干旱少雨,多风,导致了土壤水分蒸发量大,土壤盐分含量增高,对玉米的生长发育产生危害,制约了玉米产量的提高.针对这一问题,文章从土壤改良、整地、适时播种、田间管理,以及科学施肥等方面总结了盐碱地玉米栽培技术.     

天津地区杜鹃花管护措施

针对天津地区夏季高温,冬季干燥,土壤盐碱,不适宜杜鹃花生长的问题,提出应合理调控肥、水,以达到杜鹃花在春节时开花的最佳观赏效果.     

27%甲基磺草酮·阿特拉津悬浮剂防治玉米田杂草药效试验

27%甲基磺草酮.阿特拉津悬浮剂防治玉米田间杂草试验表明,300g a.i./hm2处理对阔叶杂草的目测防效和鲜重防效均在90%以上,对稗草、狗尾草的防效在70%以上,总体防效大于80%。通过混用在降低阿特拉津使用量减少土壤残留的同时,又提高了防除阔叶杂草,特别是显著提高了防除禾本科杂草的效果。     

30％氟唑菌酰羟胺·噁霉灵种子处理悬浮剂的配方研究

研制了一种以氟唑菌酰羟胺和噁霉灵复配为原药,30%有效成分含量的悬浮剂。试验通过对不同表面活性剂(润湿分散剂、乳化剂)、增稠剂、成膜剂、防冻剂等的筛选,得到较优配方:氟唑菌酰羟氨10%、噁霉灵20%、500LQ 2%、D305 2%、T80 1%、黄原胶0.2%、硅酸镁铝1.2%、液体硅酸钠3%、丙二醇4%、消泡剂0.4%,水补足至100%。试验结果表明,该产品悬浮率90%以上,热储[(54±2)℃]分解率5%,产品其他各项指标符合悬浮剂要求。     

控释肥对土壤养分和杏树生长及产量品质的影响

为了明确控释肥在杏树上的施用效果,以普通复合肥(CCF)做对照,研究了等量控释肥(RCF1)、减量控释肥(RCF2)、减氮控释肥(RCF3)对土壤和杏树养分、杏树生长以及杏果实产量品质的影响。结果表明,控释肥养分释放基本与杏树生长相一致,能增加杏树叶片叶绿素含量,增加枝条长度,提高杏树叶片养分和冬季枝条储存养分含量,施肥效果因控释肥的种类和施用年限的不同有所差异;连续施用两年后,控释肥可以提高杏产量和果实品质;控释肥即使减量20%后,产量与普通复合肥相当,一些生长与品质指标甚至超过普通复合肥处理。     

双向SLA公平调度算法及其在EPON中的应用

研究了开放接入网络中带宽分配的公平性问题.将最大〖CD*2〗最小公平算法应用到双向SLA带宽调度算法中,给出了一种基于EPON的易于实现的双向SLA公平带宽调度算法.以用户SLA为首要SLA,以业务提供商的SLA为次要SLA,通过带宽分配和调整,实现了双向公平的带宽分配.仿真实验表明,双向SLA算法实现了业务提供商和用户的公平性需求,具有合理性和可用性.