蓄电池支架的优化设计

某车型在强化道路试验过程中,蓄电池支架产生了裂纹、断裂的现象。针对该蓄电池支架出现的问题,从机舱总布置及蓄电池支架结构两方面进行了原因分析,并根据分析结果进行了4种方案的结构设计。通过对4种结构方案进行CAE有限元分析,进而比较每种方案的应力云图。结果表明：对蓄电池支架的上下托架同时进行结构更改的这一方案,在所得的应力云图中,应力集中点处应力值最小,同时该结构件的Z向刚度值最大,因而综合结果最好。     

北京植物园植物教育功能现状与拓展

通过对北京植物园解说系统的调查,分析了其当前解说牌设置存在的五个方面问题:教育类解说牌数量偏少、植物知识及环境教育解说不足、对中国传统名花的关注不够、解说牌设置环境情景缺失、解说牌种类繁多,设计缺乏统一。针对以上问题,提出了植物园解说系统的五个方面的改进建议。     

An innovative tapping system, the double cut alternative, to improve the yield of Hevea brasiliensis in Thai rubber plantations

In Thailand, the continuous decrease in the size of rubber plantations has led to the general adoption of intensive tapping systems which may lead to over harvesting, high rates of tapping panel dryness (TPD), short life-cycles of the plantations, and low labour productivity. In Thailand, farmers use a half-spiral downward tapping system (S/2) or a one third-spiral (S/3) with a tapping frequency of once two days (d2) or more. To increase productivity, it is difficult to reduce tapping frequencies, even with ethylene stimulation, as this would result in days without work for tappers. The purpose of this study was to characterize the behaviour of the Hevea latex yield under the double cut alternative tapping system (DCA). The aim was ensure the long-term sustainability of latex yield by increasing the time required for latex regeneration between two tappings through splitting this high tapping intensity (100% or above) into two different tapping cuts tapped alternately (S/2 d47d7(t,t). Over a period of 10 years, compared to a single cut tapping system (S/2 d2) of equivalent intensity, DCA increased cumulative rubber production by 9%. Ability of the trees to produce more latex under DCA was related to the sucrose and inorganic phosphorus contents of the latex cells in each tapping panel. DCA produced metabolic activity more favourable to yield during the first 10 years of tapping. But DCA also resulted in higher TPD rates, a sign of a metabolic dysfunction of the productive bark. DCA is a new tapping system. Further research is required to optimize the use of the DCA strategy. Such research will lead to new advances in our knowledge of the physiology of the rubber tree, mainly at the trunk scale.     

基于MPI的并行Kriging空间降水插值

利用湖南1994~2008年的三次产业增加值与实际利用外资额数据,运用面板数据模型分析了FDI与产业结构之间的关系。研究发现,FDI显著提高了湖南三次产业的产值水平,却未能有效推动湖南产业结构的优化升级。     

乳业上市公司资本结构影响因素的实证研究

根据资本结构影响因素理论,选取我国8家乳业上市公司2004-2008年5年间的年报数据为研究样本,研究乳业上市公司资本结构的影响因素。结果表明,影响乳业上市公司资本结构的显著因素依次是企业盈利能力、非债务税盾、资产担保价值和企业成长性。并根据实证研究结论,提出优化乳业上市公司的对策。     

负离子材料应用于人造板制造的前景分析与展望

负离子对人体具有保健功效,对环境具有净化作用,将其与人造板材料相复合,可以有效的改善人类的生存环境。介绍了我国人造板发展现状、负离子产生的机理及其环境效应,讨论了生产负离子人造板的必要性和可行性及其发展前景     

脲醛树脂在水曲柳刨切薄木湿贴工艺中的应用

扼要介绍了湿法棉秆中密度纤维板基材表面用以脲醛树脂为主要成分的混合胶,湿贴厚度为0.25mm和0.4mm水曲柳刨切薄木的工艺,并对基材、胶粘剂、贴面材、胶贴工艺等诸多因素优化研究,比较有效地解决了透胶和脱胶等问题,制得质量合格而又有明显经济效益和使用价值的棉秆中密度纤维板薄本装饰板。研究结果表明,湿贴工艺中采用以脲醛树脂为主要组分的混合胶是可行的,胶贴质量达到日本农林省JAS标准“装饰合板”中规定的指标。     

红麻轻质阻燃人造板的研制

本文研究了红麻轻质阻燃板的生产技术,产品理想的生产工艺参数为:阻燃剂用量14%、成形压力4.0MPa、胶粘剂用量10%、热压时间为60s.mm-1热压温度120℃。产品的力学性能和阻燃性能指标如下:静曲强度≥31.85MPa;密度≤0.52g.cm-3;氧指数41%～50%;2分钟热释放率≤80kW.min.m-2,达到了相关标准的要求。     

Overview of Wood-based Panel Industry in China

The production of wood-based panel was presented firstly in this paper. Some features of China’s wood-based panel industry were reviewed, including production bases, raw materials and main markets of wood-based panel. In addition, the trade flow of wood-based panel was described in the end.     

世界各国、地区森林数据

联合国粮农组织(FAO)2001年3月发表了“2000年世界森林资源评价:概要报告书(FRA2000 Summary Report)”。该报告书中的一些数据是上次FRA1990年所没有的。此表介绍了各国和各地区的森林面积、森林覆盖率、1990～2000森林面积的年变化率及森林蓄积。