变频器的应用和存在问题及对策

我国的电动机用电量占全国发电量的60％-70％，风机、水泵设备年耗电量占全国电力消耗的1／3。造成这种状况的主要原因是风机、水泵等设备传统的调速方法是通过调节入口或出口的挡板、阀门开度来调节给风量和给水量，其输入功率大，大量的能源消耗在挡板、阀门地截流过程中。由于风机、水泵类大多为平房转矩负载，轴功率与转速成立方关系，所以当风机、水泵转速下降时，消耗的功率也大大下降，因此节能潜力非常大，最有效的节能措施就是采用变频调速器来调节流量，应用变频器节电率为20％-50％，效益显著。     

中部半干旱山区沙棘、柠条不同造林方法效果初探

地处甘肃中部的渭源县北部干旱山区，年降雨量在420-490mm之间，且多集中在7、8、9三个月，海拨高度在1980-12650m之间，年均气温在5.2-40℃之间，荒山造林土壤多为第三红黄土上发育的淋溶灰褐土，地形地貌由于水土流失严重，沟壑纵横，支离破碎，自然生态条件严酷。造林成活保存率低。较适宜于柠条（陕北柠条）沙棘（中国沙棘）生长。为探讨柠条、沙棘植苗造林和直播造林的经验与技术、寻找以最小的造林成本来获得较大成活保存率，本人亲自设立柠条、沙棘种子直播和苗子栽植两种造林方法，进行了三年的对比观察，现将试验对比效果初报如下：     

Determination on ^87Sr/^86Sr ratio and stratigraphic dating of single-grain foraminifera

Information on palaeoocean and palaeoclimate can be recorded in foraminifera, and formation ages of the fo- raminifera are nevertheless essential for such study of pa- laeoenvironment. The growth rate of seamount ferroman- ganese crusts is normally very l…     

SHRIMP zircon U-Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province, middle-lower reaches of the Yangtze River and its implications

The Jinniu Basin in southeast Hubei,located at the westernmost part of middle-lower val-ley of the Yangtze River,is one of the important vol-canic basins in East China. Volcanic rocks in the Jin-niu Basin are distributed mainly in the Majiashan Formation,the Lingxiang Formation and the Dasi Formation,consisting of rhyolite,basalt and basaltic andesite,(trachy)-basalt and basaltic trachy-andesite and (trachy)-andesite and (trachy)-dacite and rhyolite respectively,in which the Dasi volcanism is volumet-rically dominant and widespread. The Dasi volcanic rocks were selected for SHRIMP zircon U-Pb dating to confirm the timing of volcanism. The results indi-cate that there exist a large amount of magmatic zir-cons characterized by high U and Th contents in the volcanic rocks. The concordia ages for 13 points are 128 ± 1Ma (MSWD = 3.0). On account of the shape of zircons and Th/U ratios,this age is considered to represent the crystallization time of the Dasi volcan-ism. The volcanic rocks in the Dasi,Majiashan and Lingxiang Formations share similar trace elementand REE partition patterns as well as Sr-Nd isotopic compositions. In combination with the regional geol-ogy,it is proposed that the southeast Hubei volcanic rocks were formed mainly during the Early Creta-ceous,just like other volcanic basins in middle-lower Yangtze valley. A lithospheric extension is also sug-gested for tectonic regime in this region in the Cre-taceous Period.     

Growth ages of ferromanganese crusts from the western and central Pacific： Comparison between nannofossil analysis and ^10Be dating

Based on results of nannofossil analysis and 10Be dating in ferromanganese crusts M1-1 and A1-1 (no nannofossils were found in it),from the western and central Pacific respectively,it is found that the crust growth ages from nannofossil biostrati-graphy agree well with those based on 10Be isotope analysis. Both crusts have three growth layers,and the oldest layer was deposited in Miocene at about 12.80 Ma. The maximum,minimum,and average growth rates of crust A1-1 (from the central Pacific) are 8.11,1.92 and 3.47 mm/Ma,and those of crust M1-1 (from the western Pacific) are 2.93,0.47,and 0.94 mm/Ma.     

银川市“十一五”科学技术发展规划

在全面建设小康社会的历史进程中，未来五年是我国走自主创新道路、建设创新型国家的重要战略机遇期，也是银川建设“两个最适宜”城市的重要时期。这一时期科学技术的发展，对大力提升银川的自主创新能力，构建“创新型银川”，促进经济社会又快又好发展，具有重大而深远的战略意义。根挥《国家中长期科学和技术发展规划纲要》和《宁夏回族自治区“十一五”科学技术发展规划》及《银川市国民经济和社会发展第十一个五年规划》的总体部署和要求，特制定银川市“十一五”科技发展规划。     

2003年广东省生产力促进中心统计报告

2003年1月1日，《中国人民共和国中小企业促进法》开始实施，中小企业的发展，在客观上迫切需要中介机构的服务，这为生产力促进中心的发展增多了一份契机。2003年8月，全国科技中介机构宣传月更将“科技中介机构建设年”的气氛推向高潮，科技中介机构进入社会公众的视野。2003年11月，省科技厅召开广东省科技服务体系建设工作会议，强调加强科技服务体系建设，大力促进科技成果转化，为我省生产力促进中心工作指明了前进的方向。     

2003:北京科技亮点回眸

转眼间,2003年已经过去。这一年,北京的科技工作再上台阶,首都二四八重大创新工程取得重大进展,科技政策的完善,使得高新技术产业已经成为首都经济的支柱产业。回顾2003年北京的科技亮点,不难发现,科技的力量正在北京的建设发展中起着愈来愈重要的作用。     

注重提高学术质量 扩大学报影响力度江苏省高校学报研究会2004’年会在南京举行

2004年9月22日至24日，江苏省高校学报研究会2004’年会在南京师范大学南山专家楼隆重举行。吴增基理事长就两年来的工作及今后的工作思路作了工作报告。     

桂西晚古生代玄武岩Ar-Ar和U-Pb年代学及其对峨眉山玄武岩省喷发时代的约束

桂西一带呈层状、似层状产出的晚古生代玄武岩具有与峨眉山溢流玄武岩中高Ti玄武岩相似的元素-同位素地球化学组成. 对区内典型火山岩剖面的关键层位玄武岩样品进行了高精度全岩⁴⁰Ar/³⁹Ar和SHRIMP锆石U-Pb定年. 结果表明, 阳圩剖面上部、玉凤和民安剖面下部玄武岩分别给出了253.6±0.4, 255.4±0.4, 256.2±0.8 Ma的⁴⁰Ar/³⁹Ar坪年龄. 阳圩剖面上部玄武岩中锆石给出了253.7±6.1 Ma的²⁰⁶Pb/²³⁸U加权平均年龄. 结合峨眉山溢流玄武岩区已有年代学资料认为, 峨眉山大火成岩省最早启动于约260 Ma, 该火成岩省的大规模快速喷发发生在253~256 Ma, 251~253 Ma的中酸性岩石代表该火成岩事件的晚期产物. 峨眉山火成岩省自启动到消亡的时间范围变化于251~260 Ma间, 大致耦合于Guadalupian末与P/Tr边界的环境突变与生物绝灭. 桂西晚古生代玄武岩精细年代学的确定为厘定峨眉山火成岩事件的主体喷发时代和理解峨眉山溢流玄武岩中高Ti玄武岩的时空格局和地幔柱动力学机制提供了资料.