不同类型水处理剂对马海盐湖高不溶物钾盐矿浆的絮凝沉降及过滤性能研究          下载免费PDF全文

马金元  李海民  边红利  张全有 《盐湖研究》2012,20(1):40-43

研究了焦磷酸钠、三氯化铁、硫酸铁、硅酸钠、丙酮、十二烷基硫酸钠、十二烷基苯磺酸钠、聚乙二醇等一些水处理剂与非离子聚丙烯酰胺组合后对马海盐湖高不溶物、低品位固体钾矿矿浆的絮凝沉降效果,找出了对钾矿矿浆絮凝沉降、过滤分离有较好效果的药剂组合。  相似文献   

新时期长江三角洲区域联动发展的战略性思考   总被引：4，自引：1，他引：3  

殷为华 《地理与地理信息科学》2004,20(5):67-71

该文通过分析世界经济竞争空间主体、国际产业梯度转移方式、国内区域经济竞争格局的新变化,论述了长江三角洲地区实施区域联动发展战略的必要性。剖析长江三角洲地区实现联动发展的主要动力机制在于国内外经济竞争压力、企业跨地区发展、政府间经济合作、区域基础设施一体化。提出长江三角洲实现区域联动发展的主要领域和对策。  相似文献   

On linking coefficient of two Keplerian orbits     

Konstantin V. Kholshevnikov  Nikolay N. Vassiliev 《Celestial Mechanics and Dynamical Astronomy》1999,75(1):67-74

We define a function of the set of pairs of Keplerian ellipses so that the sign of the function will be a topological invariant of their configuration. The sign is negative if and only if the related ellipses are linked. Two modifications of the coefficient which are more reliable in the case of closed to coplanar orbits are proposed. Explicit formulae representing the linking coefficients as functions of orbital elements are deduced. Extension in the case of unbounded orbits is obtained. We suggest different ways to use these coefficients for determining intersections of pairs of osculating Keplerian orbits. If we study dynamical behaviour of geometric configuration of pairs of Keplerian orbits, we can fix the moments of their intersections. These moments correspond exactly to the vanishing of linking coefficients. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Urban development in Germany — perspectives for the future     

C.-C. Wiegandt 《GeoJournal》2000,50(1):5-15

The essay portrays urban development in Germany at the end of the 20th century in the transition from Industrial Modernity to the New Modernity. The city of the Industrial Modernity is described as a traditionally closed and mixed city. It corresponds to the classical European model of the compact city with a clearly defined centre and a surrounding area which is unambiguously oriented towards this centre. This urban model is disintegrating in Germany. The essay explains this lingering but fundamental process of change. The inner cities are decreasing in importance in favour of the urban fringe, traditional relationships and connections with our cities are lost, new regional activity areas are emerging in the environs of cities. Although the urban impacts of new communication technologies have not been completely clarified, they are changing previous local relationships in the cities. This is not without consequences for urban neighbourhood relationships. The increasing polarisation in German society also affects urban structure. The social mixture in cities disappears on a small scale, public spaces are losing their functions, undesirable population groups are excluded from participation in urban life in new shopping, leisure and transport facilities. The interaction between private and public agents who influence and determine urban development has changed in recent years, and the civic sense of responsibility for the city must be newly defined. Hopes are put into the debates on the Local Agenda and - in spite of its dangers - into a project-oriented planning approach.  相似文献   

Toxicity Study of Anti-HABs Agents on Penaeus chinensis     

孙晓霞  张波  俞志明 《海洋通报(英文版)》2001,3(1)

In order to study the effect of anti-HABs agents on Penaeus chinensis, the toxicity experiments on clay, Ca(ClO)2, FeCl3, and AlCl3 to Penaeus chinensis are carried out. The results show that: (1) the clay isn't toxic to Penaeus chinensis; (2) Ca(ClO)2 has no toxicity to Penaeus chinensis at low levels, but has acute and chronic toxicity at high levels; (3) Penaeus chinensis can accumulate Fe and Al. The toxic effect needs further study.  相似文献   

Ledgers and landscapes: Indicators of rural landscape change in southern New Zealand, 1878–1919          下载免费PDF全文

Peter Holland  Sherry Olson 《New Zealand geographer》2017,73(1):45-56

Our objective was to develop and calibrate numerical measures to represent the timing and magnitude of landscape change between 1878, and 1919 using information in a stock and station agency's ledgers. Relative expenditures on fencing materials peaked in the 1880s, were lowest in the early 1900s, and rose to one‐fifth of annual expenditures from 1914 onwards. In contrast, relative expenditures on soil preparation, cropping and harvesting grew steadily after 1879, peaked in 1900, and declined from then until 1919. This research found that periods of intensive landscape investment between 1878 and 1919 were separated by longer intervals of landscape maintenance.  相似文献   

多智能体系统的群集行为研究综述     

胡鸿翔  梁锦  温广辉  虞文武 《南京气象学院学报》2018,10(4):415-421

近些年来,多智能体系统的群集行为分析已成为复杂网络领域的一个研究热点.本文从个体内部动力系统与个体间的拓扑结构这两个因素出发,对多智能体系统的群集行为问题的发展现状进行概述,并对相应的分布式协议、收敛速度以及实现的条件做了介绍和分析.最后,结合目前的研究现状,讨论了群集行为未来的研究方向.  相似文献   

提高完井电测一次成功率的钻井液技术对策          下载免费PDF全文

王方博  王兴忠  杨国兴  曾艺  龚德章 《探矿工程》2016,43(11):36-40

近年来,随着油气勘探开发的深入,大斜度井、水平井的增多,定向井及水平井位移越来越长,遇阻通井现象频频发生,完钻电测一次成功率低,影响了建井周期。本文通过对川西、川东北等地区部分定向井及水平井完井电测遇阻原因分析,从钻井液角度出发,提出“强抑制-交联-固壁”技术、高效润滑段塞技术等相应对策提高电测一次成功率。现场应用表明,这些钻井液技术对策为提高完井电测一次成功率、解决电测遇阻问题提供了新的思路。  相似文献   

Spatial distribution of human geomorphic activity in the United States: comparison with rivers     

Roger LeB. Hooke 《地球表面变化过程与地形》1999,24(8):687-692

By some measures, the role of humans in shaping the landscape is now greater than that of any other geomorphic agent. This effect varies spatially. In the United States, it is greatest in the east where population density is highest, and particularly in West Virginia and neighbouring states where coal mining is added to more general earth-moving activities. For comparison, rivers in the United States move less soil, and their influence is greatest in the western part of the country where steep, sparsely vegetated slopes contribute to high sediment loads. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

苏北盆地阜宁组三段油藏低中渗储层保护技术研究及应用     

刘伟  ;彭商平 《海洋地质译丛》2009,(1):105-109

苏北盆地阜宁组三段油藏属低中渗储层。在储层敏感性与损害机理研究基础上,通过对油田开发全过程的储层损害因素分析,认为钻井液和注入水是损害储层的两个主要因素。着重研究了保护阜三段油藏储层的钻井液技术,开发了保护储层的改性正电胶钻井液体系和屏蔽暂堵剂。现场应用表明：该钻井液体系能明显降低表皮系数,试验井油井的平均产量比非试验邻井增产三成以上,储层保护效果明显。  相似文献