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排序方式: 共有1288条查询结果,搜索用时 15 毫秒
41.
合作型的全球城市——德国城市体系研究及其对上海的启示 总被引:2,自引:0,他引:2
与美国,英国和日本不同,德国作为世界上最重要的经济体之一,并没有一个顶级的全球城市.对德国城市体系的分析显示,德国拥有一个由多个重要城市构成的城市体系网络,城市间存在良好的劳动分工和专业化协作,且具有高度的交通可达性.这种城市体系结构加强了区域之间的竞争,有利于发现更好的问题解决方法,而且与单一的全球城市相比具有较低的拥堵成本.这种城市体系并没有影响甚至是强化了德国企业在世界高端产品生产上的优势地位,德国企业也并没有因缺少单一的全球城市而丧失了全球经济的控制权.因而,从成效出发,德国城市系统可以被看作是一个合作型的全球城市.这样的经验为上海建设国际经济、金融、贸易和航运中心提供了新思路,未来的国际经济中心城市应该突破上海行政界限,定位为长三角地区合作共建的全球城市.为此,长三角城市间要合理分工和专业化协作,以市场机制为根本实现路径,并进一步提高城市间的交通可达性. 相似文献
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Marek Dietrich 《Mechanism and Machine Theory》1972,7(4):427-442
The subject of this paper is the analysis of the maximum loading of ties in multiband frictional systems. Systems like these occur in different branches of mechanical engineering; they are commonly used for passengers elevators. Although the rope system of the elevator contains rockers, in order to equalize the loading of the separate bands, remarkable differences in loading do occur.
Conditions of static equilibrium of the rope system, having the form of inequalities, have been found. Programming methods have been applied, to find the maximum loading of ropes which can occur in different multiband systems. Results of the analysis have been compared with the results of experiments. 相似文献
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Nanoporous gold bumps have been deposited on silicon wafers by electroplating a silver–gold alloy followed by etching the silver. An open-porous cellular structure of gold at meso-scale is left on top of the bumps. For flip chip bonding we found low temperature and low force bonding conditions. The porous interconnects have very promising properties, like compressibility and reduced stiffness, which should result in higher bond yield and extended reliability. 相似文献
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Robert Sevenich Elke Kleinstueck Colin Crews Warwick Anderson Celine Pye Katerina Riddellova Jaromir Hradecky Eliska Moravcova Kai Reineke Dietrich Knorr 《Journal of food science》2014,79(2):M230-M237
The benefits that high‐pressure thermal sterilization offers as an emerging technology could be used to produce a better overall food quality. Due to shorter dwell times and lower thermal load applied to the product in comparison to the thermal retorting, lower numbers and quantities of unwanted food processing contaminants (FPCs), for example, furan, acrylamide, HMF, and MCPD‐esters could be formed. Two spore strains were used to test the technique; Geobacillus stearothermophilus and Bacillus amyloliquefaciens, over the temperature range 90 to 121 °C at 600 MPa. The treatments were carried out in baby food puree and ACES‐buffer. The treatments at 90 and 105 °C showed that G. stearothermophilus is more pressure‐sensitive than B. amyloliquefaciens. The formation of FPCs was monitored during the sterilization process and compared to the amounts found in retorted samples of the same food. The amounts of furan could be reduced between 81% to 96% in comparison to retorting for the tested temperature pressure combination even at sterilization conditions of F0‐value in 7 min. 相似文献
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The increasing demand for electric vehicles and thus lithium-ion batteries results in a multitude of challenges in production technology. The reproducibility and performance of large scale batteries for automotive applications are very high. At the same time the production processes are complex and involve many uncertainties. Two essential process steps are the electrode coating and electrode package assembly. The mass loading of anodes and cathodes are determined by the coating process, where deviations can be caused by different reasons. The selective assembly of the electrodes is a reasonable way to balance the production variances. The contribution shows extended algorithms and their benefits and drawbacks of matching electrodes in order to improve the subsequent electrode packaging process. Here, the aim is to reach higher cell capacities and optimized performance values by “optimally” balanced electrodes regarding the mass loading ratio, which is also related to the specific material capacity. 相似文献
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