CPLD技术及其在现代时统中的应用

对CPLD(复杂可编程逻辑器件)技术的基本特征和发展趋势作了简要介绍,揭示了该技术在现代数字系统中的重要地位及作用.利用CPLD对时统设备IRIG-B码产生器进行集成,其实验结果表明,集成了的B码产生器不但简单、可靠,而且便于调试,克服了以往硬件电路复杂的缺点.     

Effect of spatial variation characteristics on contouring of design storm depth

The ordinary kriging method, a geostatistical interpolation technique, was applied for developing contour maps of design storm depth in northern Taiwan using intensity–duration–frequency (IDF) data. Results of variogram modelling on design storm depths indicate that the design storms can be categorized into two distinct storm types: (i) storms of short duration and high spatial variation and (ii) storms of long duration and less spatial variation. For storms of the first category, the influence range of rainfall depth decreases when the recurrence interval increases, owing to the increasing degree of their spatial independence. However, for storms of the second category, the influence range of rainfall depth does not change significantly and has an average of approximately 72 km. For very extreme events, such as events of short duration and long recurrence interval, we do not recommend usage of the established design storm contours, because most of the interstation distances exceed the influence ranges. Our study concludes that the influence range of the design storm depth is dependent on the design duration and recurrence interval and is a key factor in developing design storm contours. Copyright © 2003 John Wiley & Sons, Ltd.     

Analytical solutions of one‐dimensional infiltration before and after ponding

This paper is a continuation of previous research, which obtained a convenient solution for arbitrary surface fluxes before ponding. By means of Fourier Transformation this has been extended to derive analytical solutions of a linearized Richards' equation for arbitrary input fluxes after surface saturation. Copyright © 2003 John Wiley & Sons, Ltd.     

加强技术创新服务地质调查——庆祝探矿工艺研究所成立30周年

为加强地质探矿技术力量,改变地质装备落后现状,经国务院批准,1978年8月8日成立了探矿工艺研究所。30年来,经过新老两代工艺所人的艰苦奋斗、刻苦钻研、勇于创新,在科研攻关、成果转化、基地建设和管理等方面都取得了可喜的成绩,为国家的地质科学事业做出了贡献,目前已成为一个“以勘查技术为基础,以承担地质调查任务和科研项目、提供勘查与监测技术方法和技术服务为手段,以服务国家经济建设、社会发展和地质工作为目标,以探矿工艺技术和地质灾害监测防治技术研发为主业”的地质调查科研机构。回顾了工艺所艰苦创业、改革进取的发展历程,对科技体制改革、专业结构调整、人事分配制度改革、地质调查和科研工作进行了总结,展示了丰硕的科研成果和强劲的科技实力;指出了工艺所在“十一五”期间地质调查和科研工作的重点领域和优先发展方向。     

Variational iteration solving method for El Nio phenomenon atmospheric physics of nonlinear model

1 IntroductionThe El Ni’o atmospheric physics oscillation is anabnormal phenomenon involved in the tropical Pacificocean- atmosphere interactions. Studies on the El Ni(ophenomenon are very attractive (Lin et al., 2000; Linet al., 2001, 2002; Wang, 2001; Feng et al., 2001;Feng et al., 2002; Liu et al., 2002; Wei and Chen,2003; Xie et al., 2002; Zhu et al., 2002; Pu et al.,2003; Gu et al., 2004; Yu and Liu, 2004). Lin and Mo(2004), Mo and Lin (2004) and Mo et al. (2004) alsostudied a s…     

Observational evidence of the upwelling off cape shioyazaki in Fukushima Prefecture,Japan

Using serial observations, evidence of the existence of upwelling in the region between the northeast flowing Kuroshio and the coast of Ibaraki and Fukushima Prefectures is presented. The complex and variable oceanic condition in this region sometimes conceals some of the evidence of upwelling. Evidence of upwelling can be seen in the distributions of temperature and salinity, and more clearly in those of dissolved oxygen and phosphate. The average position of the upwelling region is just off Cape Shioyazaki in Fukushima Prefecture. Such an upwelling phenomenon may be a general oceanic feature characteristic of the region at the poleward edge of western boundary currents.     

基于EMD与神经网络的机械故障诊断技术

经验模式分解 (EMD)是分析非线性、非平稳信号的有力工具 ,它将信号分解为突出了原信号的不同时间尺度的局部特征信息的内在模函数 (IMF)分量。本文通过将各 IMF分量输入到 BP网络中进行训练学习和故障诊断 ,比直接输入原信号可以提高 BP网络对故障诊断的准确率 ,而且减少了训练时间。     

现代黄河三角洲粉土触变性研究及其应用

通过对现代黄河三角洲砂质粉土和粉质粘土触变性的对比试验研究，阐述了黄河口粉土的触变性。试验结果对解释粉土的失稳机制、解决工程地基的稳定性和防止地质灾害等具有重要的现实意义。     

哀牢山-红河断裂带中段应变分析

对哀牢山—红河断裂带中段和平—水塘剖面、墨江—元江剖面和其它地段的岩石应变及磁组构进行了分析，表明应变强度的校正磁各向异性度PJ从断裂带向西至三叠系明显降低，变形强度向西迅速减弱。磁化率椭球体主轴展布反映出剪切带内、外变形方式的改变。剪切带内，以水平走滑运动为主；向西则以水平缩短为主。在应变分析中，对断裂带内的S—C组构两组面理夹角、杏仁体和石榴石应变标志体进行了测量，结果显示，剪切带内的磁组构和岩石组构间关系较差。此外，还对这两条剖面中的三叠系进行了应变和磁组构分析，找出了它们与磁化率椭球体对应轴率间的相关性。     

南海“耗氧”及“贫氧”水体中消耗氧与硝酸盐和磷酸盐再生比值估算

通过对南海深海区硝酸氮、活性磷酸盐垂直分布的研究,分析了南海垂向耗氧和贫氧水体中硝酸氮、活性磷酸盐和表观耗氧量之间的关系.结果表明垂向上次表层、中层和深层水团中氧的消耗与营养盐再生比值均小于理论值,由此推断水体的混合为有机物再矿化提供氧的补充,但水团混合对水柱中硝酸氮、活性磷酸盐的影响不大,在次表层和中层水团中造成营养盐浓度变化主要是由于有机物再矿化的结果;在深层水团中有机物再矿化对水柱中营养盐梯度变化已不占主导地位.