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61.
历史中心区复兴中的地域性问题与对策 总被引:2,自引:0,他引:2
本文以上海思南路47~48街坊改造为例,探讨城市形态更新与居民外迁问题,并期待相关地域性社会对策的出现。 相似文献
62.
采用高频脉冲电铸工艺制备出了镍钴纳米复合块体材料,利用场发射扫描电镜、能谱和X射线衍射的方法,重点研究了复合块体沉积层的表面形貌、相结构和结晶取向。结果表明.高频率和润湿剂的添加对沉积层的细化有重要影响,高频脉冲电铸能够获得微观组织致密、均匀的复合块体材料。 相似文献
63.
64.
The application of the eXtended finite element method (X-FEM) to thermal problems with moving heat sources and phase boundaries
is presented. Of particular interest is the ability of the method to capture the highly localized, transient solution in the
vicinity of a heat source or material interface. This is effected through the use of a time-dependent basis formed from the
union of traditional shape functions with a set of evolving enrichment functions. The enrichment is constructed through the
partition of unity framework, so that the system of equations remains sparse and the resulting approximation is conforming.
In this manner, local solutions and arbitrary discontinuities that cannot be represented by the standard shape functions are
captured with the enrichment functions. A standard time-projection algorithm is employed to account for the time-dependence
of the enrichment, and an iterative strategy is adopted to satisfy local interface conditions. The separation of the approximation
into classical shape functions that remain fixed in time and the evolving enrichment leads to a very efficient solution strategy.
The robustness and utility of the method is demonstrated with several benchmark problems involving moving heat sources and
phase transformations.
Received 20 May 2001 / Accepted 19 December 2001 相似文献
65.
Robert L. Hirsch 《Journal of Fusion Energy》2002,21(2):113-116
Assuming significant technical success in the ITER project by the year 2015, it is likely that governments will want to develop a more comprehensive plan for DT tokamak fusion power commercialization. To provide a glimpse into many of the related issues, we construct conversations between the director of the U.S. fusion program and three specialists key to commercial fusion success: an environment and safety regulator, an environmentalist, and an electric generation investor. The insights from these imagined conversations will hopefully be of value as tokamak fusion power proponents plan beyond ITER. 相似文献
66.
Methyl groups from chain scission and H-crosslinks have been identified by solid-state nuclear magnetic resonance in amorphous ethylene-propylene copolymers containing 23 and 36 mole % propylene after γ-irradiation to 10 MGy at 30°C. G (scission) and G (crosslink) values determined from the n.m.r. spectra and by extraction are in agreement, which suggests that the crosslinks are not clustered. This may differ from the situation in polyethylene where there is a substantial crystalline content. G(S). G(X) and the ratio G(S)/G(X) increase with increasing propylene content of the copolymers. 相似文献
67.
喷射导管技术在深水钻井作业中的应用 总被引:9,自引:1,他引:8
深水油气日益成为海洋石油勘探开发的热点,但深水钻井作业面临着许多难题和挑战,喷射导管技术是解决深水浅层钻井难题的技术之一。该技术采用在喷射管柱内下动力钻具的方式,用钻入泥线以下的管串自身重力钻进,喷射到位后利用地层的粘附力和摩擦力稳固住导管,起出送入工具和管内钻具,完成导管的安装。喷射导管技术可避免因水泥浆密度过大而压破地层,也可避免深水由于低温等因素影响固井质量。我国第一口水深超千米的深水井——荔湾3-1-1井利用该技术成功完成了导管的安装,井口装置没有出现井口失稳的问题。随着我国深水勘探步伐的加快,越来越多的深水区块将投入勘探开发,喷射导管技术具有良好的应用前景。 相似文献
68.
无线局域网技术及应用 总被引:9,自引:0,他引:9
无线局域网技术是目前发展迅速的技术,相对于有线局域网有许多优点。随着无线网络产品性能的提高和价格的不断下降,无线局域网技术有着广泛的应用前景。据此对无线局域网的基本概念、特点及其技术作了简单的介绍,提出了无线局域网面向应用的几种解决方案,并对发展前景作了预测。 相似文献
69.
Experimentally determined p,V,T data are reported for toluene, trichloromethane, dichloromethane, acetonitrile, aniline, and n-dodecane at 278, 288, 298, 313, and 323 K, except for dichloromethane, for which the highest temperature was 298 K. At each temperature, measurements were done at pressures up to about 280 MPa or (for aniline and n-dodecane) at a lower pressure slightly below the freezing pressure at the temperature of measurement. Values of the isobaric expansivity isothermal compressibility and (for toluene, trichloromethane, dichloromethane, and acetonitrile) internal pressure, derived from the p,V,T data, are presented. 相似文献
70.
T.F. Zabel 《臭氧:科学与工程》1985,7(1):11-30
Only two water works in the UK apply ozone at present as part of their treatment, onefor taste and odor control and theother forcolor removal. Forthetwo applicationus ozone was the most economical option at thetime theplants were installed andozone has been successful for the purpose for which it was designed. 相似文献