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吐哈盆地十红滩铀矿床地质特征及控矿因素分析 总被引:1,自引:0,他引:1
李保侠 《华东地质学院学报》2002,25(4):292-300
叙述了吐哈盆地地质概况;十红滩铀矿区找矿目的层地质和砂体特征;重点对层间氧化带的纵横展布规律、地球化学分带性及前锋与铀矿化的关系作了阐述;对十红滩铀矿床南、北矿带的空间分布、形态、规模、物质成分、铀存在形式及南、北矿带差异做了研究。通过分析,最后得出十红滩铀矿床控矿因素是层间氧化带、鼻状隆起(南矿带)和北西向断裂构造(北矿带)、同时说明了局部铀矿化产出的决定因素。 相似文献
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研制的多功能为数字化地籍测绘系统,其集数据传输,平差计算,碎部点处理,图形处理和报表输出为一体,既适合于全站仪,并站仪,也可采用电子平板作业方式。该系统已用于生产中,效果好。 相似文献
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Andrew J. Murphy 《Geoforum》2007,38(5):941-953
This paper addresses the materiality of computer-mediated retailing. The paper uncovers the “hidden geography” of e-commerce, considering how the seemingly simple act of doorstep food delivery is explicated in urban form, and in transportation and communication infrastructures. The paper categorises electronic grocery shopping (EGS) enterprises into three types: “bricks and clicks”, “pure-play” and the “infomediary”, and examines how each type of operation has been materialised in the urban landscape, and the infrastructure upon which each draws. The paper then considers the strategies EGS operations have used to offset the “killer costs” of logistics for electronic commerce. The paper concludes by considering how electronic grocery shopping is embedded within broader trends in consumer behaviour, and how these trends are manifested in the materiality of urban life. The paper argues that online grocers are in the vanguard of ventures habituating customers to the remote ordering and delayed delivery of products to the home. Through controlling this “last mile”, online retailers hope to extend the product offer to higher-margin and more problematic products, which are in themselves unprofitable to distribute direct to the customer, but which can be profitably combined with a grocery shop. 相似文献
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Sunil Herat 《洁净——土壤、空气、水》2007,35(4):305-310
Electronic waste or e-waste is one of the fastest growing areas of the international waste stream and is increasing at a much higher rate than all other waste streams. Fast growing electronics industries arising from the demands of information and communication technologies around the world coupled with the rapid product obsolescence and lack of end-of-life management options, have all led to the unsustainable management of the waste stream. Computers are manufactured from over 1,000 materials, many of which are toxic, and they contribute significantly to the e-waste stream, which is estimated to be ca. 20 to 50 million tonnes annually. Design for environment cleaner production, extended producer responsibility, standards and labeling, product stewardship, recycling and remanufacturing are some of the practices adopted by various countries around the world to deal with the e-waste stream. An overview of these practices is presented and the manner in which they contribute to the sustainable management of e-waste is discussed. 相似文献
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介绍了一种电子继电器,具有对恒温系统中加热元件的无触点控制和无级设定功率,以及自动适应电压变化的补偿功能。 相似文献
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彩色地图的出版印刷和一般的彩色图文的出版印刷有很多相似之处 ,但也有不同之处。本实验选择了一幅有代表性的地图 ,图内要素不仅包括水系 ,道路 ,居民地和等高线 ,而且还有分层设色 ,图外还有彩色附图和文字说明。尝试运用常用桌面出版系统制作 ,直接得到 5张 A4幅面的分色晒版胶片 (黄、品红、青、黑和棕专色 )。实验结果证明 ,桌面出版系统软件功能较全面 ,可以制作和出版地图 ,尤其是适合制作和出版带有广告 ,彩色图片的专题地图和影像地图 相似文献
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Developments in theoretical and empirical modelling of bedload transport processes are hindered by the lack of an adequate data base for testing or establishing the models. Conventional methods of measuring bedload transport rates fail to provide the necessary continuous or frequent record of variations at a single section. Acoustic techniques have the potential to overcome this deficiency, but their application has been very limited. Some of the problems of calibrating an acoustic device in the field and in a laboratory flume are discussed, and a possible circuit design described which might minimize calibration difficulties by automatically subtracting the noise generated by flow turbulence. 相似文献