大塘水库段路堤设计方案选择及实施

结合潭邵高速公路大塘水库的实际情况，针对大塘水库段路堤设计方案进行分析比较，提出采用加筋土挡土墙的方案及方案实施工艺。加筋土挡土墙的墙面位移与沉降预测结果表明此方案技术是合理可行的。     

AHP在公路主枢纽站场 总体布局规划中的应用*

为使我国公路网“三主一支持”的规划建设建立在易操作,可定量化的基础上,利用简便 实用的层次分析法建立了公路主枢纽站场总体布局方案比选模型,进而对定量、定性判断矩阵分 别提出了相应的分析构成方法,并给出了比选模型的计算过程及应用实例。经实践证明,该方法 是可行的。      

液冷和冷媒直冷动力电池包冷却性能数值分析

采用数值模拟的研究方法，对比分析了某纯电车型在高速超速以及驱动耐久工况下动力电池包采用液冷和冷媒直冷两种方案的冷却性能，研究结果表明，对于高速超速工况，相对于液冷方案，采用冷媒直冷电池包温度降低了约10%；对于驱动耐久工况，采用冷媒直冷方案电池包温度降低了约 16%，与此同时，电池包均温性也有所改善。在相同工况条件下，动力电池包冷媒直冷的冷却性能优于液冷。     

Sampling of alternatives for route choice modeling

This paper presents a new paradigm for choice set generation in the context of route choice model estimation. We assume that the choice sets contain all paths connecting each origin–destination pair. Although this is behaviorally questionable, we make this assumption in order to avoid bias in the econometric model. These sets are in general impossible to generate explicitly. Therefore, we propose an importance sampling approach to generate subsets of paths suitable for model estimation. Using only a subset of alternatives requires the path utilities to be corrected according to the sampling protocol in order to obtain unbiased parameter estimates. We derive such a sampling correction for the proposed algorithm.Estimating models based on samples of alternatives is straightforward for some types of models, in particular the multinomial logit (MNL) model. In order to apply MNL for route choice, the utilities should also be corrected to account for the correlation using, for instance, a path size (PS) formulation. We argue that the PS attribute should be computed based on the full choice set. Again, this is not feasible in general, and we propose a new version of the PS attribute derived from the sampling protocol, called Expanded PS.Numerical results based on synthetic data show that models including a sampling correction are remarkably better than the ones that do not. Moreover, the Expanded PS shows good results and outperforms models with the original PS formulation.     

船舶制冷系统的清洁船舶标志应用

介绍了法国船级社规范中有关船舶制冷系统的附加环保标志CLEANSHIP(清洁船舶)的内容,以及在某型化学品船上实施的情况。对中央空调和冷藏设备的制冷剂选用、回收再利用和泄漏报警等方面作了论述,为后续新船设计和建造提供了借鉴。     

中国航运界关于限制CFCs对策研究

正当近期内，氯氟烃物质（ＣＦＣｓ和ＨＣＦＣｓ）面临着被限制使用或被替代的严峻形势，本文分析了禁用氯氟烃的实质，及其对我国航运界的影响，特别对于远洋运输业的影响。并通过对国内外ＣＦＣｓ替代技术的进展的分析研究，提出我国航运界关于限制ＣＦＣｓ的对策。     

DETERMINATIONSOFREFRIGERANTCHARGEOFAREFRIGERATORWHENREFRIGERANTISREPLACEDBYR134aORR152a

ＤＥＴＥＲＭＩＮＡＴＩＯＮＳＯＦＲＥＦＲＩＧＥＲＡＮＴＣＨＡＲＧＥＯＦＡＲＥＦＲＩＧＥＲＡＴＯＲＷＨＥＮＲＥＦＲＩＧＥＲＡＮＴＩＳＲＥＰＬＡＣＥＤＢＹＲ１３４ａＯＲＲ１５２ａ＊ＤｉｎｇＧｕｏｌｉａｎｇＷａｎｇＸｉａｎｆｅｎｇＺｈａｎｇＣｈｕｎｌｕＣｈ...     

Two Phase Pressure Drop Performance of Refrigerant in a Small Horizontal Smooth Tube with 2.5 mm inside Diameter

Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresponding to the pressure gradient peak value of small tubes became higher than that of large tubes. The effect of quality to pressure drop becomes weak as the mass flux increases. The experiment data were compared with the predicated values of the state-of-the-art correlations from the open literature. The comparisons between the data and the predictions indicate that most of the state-of-the-art correlations fails to predict the experimental data.Chisholm model shows a relatively better predictive ability than the other empirical correlations although it has a mean deviation of 26.7%. But the predicated values of Chisholm model are lower by 50% than the experimental data when the quality becomes larger.     

R407C取代R22的工况计算及分析

围绕制冷剂发展历程和制冷剂技术更新进行了讨论.着重介绍制冷剂R407C替换制冷剂R22的工况计算,基于生产实践提出了制冷剂替换对系统的影响以及系统需要做出的改变.     

华能沙尔湖至哈罗铁路哈密地区接轨方案探讨

华能沙尔湖至哈罗铁路主要为华能公司、葛洲坝公司、潞新公司规划的电厂用煤需求和矿区煤炭外运服务,也是规划建设的鄯善至烟墩铁路通道的组成部分,在路网及带动地方经济发展中将发挥非常重要的作用,研究年度运量较大.结合对社会及经济效益的影响,探讨其在哈密地区接轨方案的选择.