动力总成悬置支架拓扑优化研究

采用结构拓扑优化方法,对动力总成悬置支架进行了优化.在最优拓扑结构的基础上进行结构修改后,一阶固有频率明显提高,而重量有所减小.从加强筋的优化结果来看,在平行于一阶弯曲振型方向上布置加强筋,可获得较好的效果.研究表明,在产品的概念设计阶段采用拓扑优化方法,能给产品的详细设计提供一个很好的基础.     

Discovery of Permian island-arc basalts in the Cenxi area and the tectonic significance──A piece of evidence for the paleo-Tethyan tectonic belt in western Guangdong and eastern Guangxi

Cenxi Permian basalts are the late Palaeozoic island-arc type basalts first found in South China. REE and trace element characteristics and distribution patterns show that this volcanic formation, which has been isotopically dated at 261 MaB.P. by the 39Ar/ 40Ar method, is of an active continental marginal island arc type, and that the tectonic environment at that time was an island-arc marginal sea or minor ocean basin related with the paleo-Tethyan tectonic belt in western Guangdong-eastern Guangxi.     

包含区间边界上的奇异值

引入“双向ＳＣ性质”的概念;对于具有双向ＳＣ性质的矩阵Ａ,论证了以下事实：若Ａ的奇异值σ位于Ｇｅｒｓｃｈｇｏｒｉｎ型包含区间的边界上,则σ必位于每一个Ｇｅｒｓｃｈｇｏｒｉｎ型区间的端点上．     

一种同步转速状态测定方法及其实现

提出一种同步转速状态测定方法．基于该方法设计了采用霍尔传感器的单片机测量系统．实现了对双螺旋推进器的转速和瞬时相差的准确测量,解决了无法预报“碰撞”现象的难题     

介绍一种测量大电阻的新方法

针对一般数字万用表测量200MΩ以内大电阻误差大、200MΩ以上大电阻无法测量的缺点，利用其输入电阻大、直流电压测量范围大的优点，研究出了能较准确测量200MΩ—几十GΩ大电阻的新方法，介绍了其测量原理。并对该法的测量范围和误差进行了分析。     

灰色预测在安全生产中的应用

采用灰色系统理论中的ＧＭ（１，１）模型对矿井的百万吨死亡率进行了预测，并通过残差修正提高了预测的精度。结果表明，该法具有较高的准确性。     

水污染控制模式选择的研究

水污染控制模式有三种，即浓度控制，总量控制和双轨制控制，总量控制又包括容量总量控制，目标总量控制和行业总量控制三种类型，针对不同情况选用与之相适应的污染控制模式，是实现经济上合理，技术上可行，效果上显著地控制水污染的前提，提出了选择水污染控制模式的六个依据和技术路线，并将之应用于图们江流域水污染控制研究中，取得较为满意的效果。     

广东南岭国家级自然保护区鸟类群落的研究

对广东省南岭国家级自然保护区鸟类群落、特点进行了研究．南岭国家级自然保护区有鸟类２１７种，隶属１７目、４１科．根据南岭山地植被的垂直分布，鸟类的垂直地理分布可分为５个带：①农耕区植被带（海拔２００ｍ以下）；②低山常绿阔叶林带（海拔２００～８００ｍ）；③中山山地常绿阔叶落叶混交林带（海拔８００～１４００ｍ）；④高山亚热带山地常绿针阔混交林带（海拔１４００～１７００ｍ）；⑤山顶亚热带常绿阔叶苔藓矮林带（海拔１７００ｍ以上）．     

试论北魏皇室在洛阳佛教复兴中的作用

北魏洛阳佛教的复兴与北魏皇室的扶持密切相关，皇室在经济、政治、人员参与等方面的积极扶持是其得以复兴的根本所在。     

Some evidence of drying trend over northern China from 1951 to 2004

The surface wetness index, Palmer drought sererity index and the retrieval of soil moisture over China were calculated using monthly precipitation and monthly mean surface air temperature. Based on the contrast analysis of the variation of the above three indices and precipitation, the dry/wet spatio-temporal pattern of northern China in the last 54 years was revealed, and the evidence of drying trend over northern China was analyzed, especially. The results show the following four facts: (1) The drying trend is the main characteristic of the eastern part of Northwest China and the central part of North China since the 1980s and it was enhanced in the last 15 years mainly due to the precipitation decrease and the temperature increase; (2) During the last 54 years, there was only one dry/wet shift at the interdecadal scale occurring in the eastern part of Northwest China and the central part of North China in the late 1970s, which was related to 1977/1978 global abrupt change, whereas there were three shifts in Northeast China, one was in the mid 1990s and the other two were in 1965 and 1983, respectively; (3) Unlike the variation trend of other subregions of northern China, the western part of Northwest China is currently located in a relatively wetting period, which is weak-ened due to the temperature increase; (4) The extreme drought frequency is obviously increasing in the eastern part of Northwest China, the central part of North China and Northeast China since the 1980s, which is closely related to the precipitation decrease and temperature increase in these subregions.