区域物流系统成长水平测度模型研究

为测度区域物流系统成长水平,在将物流系统分为物流功能系统、物流网络系统、物流需求系统的基础上,构建了包括物流企业竞争力、货物周转量等13项指标构成的测度指标体系,并用熵权法确定了各评价指标的权重.采用综合指数评价法对区域物流成长水平进行评价,构建区域物流成长水平测算模型.通过计算序参量成长指数推算子系统成长指数,测度物流系统成长水平.模型应用于环渤海地区,其中山东的物流系统成长水平最高,成长水平最低的是河北省,原因在于其区域物流需求子系统得分较低.结果表明,模型能较为客观地测度区域物流系统成长水平,识别物流系统薄弱环节,为物流系统完善提供建议.     

基于组合赋权和灰色相似关联度的区域公路网服务水平评价方法

为实现区域公路网服务水平的评价,在目标分解的基础上,从定性与定量相结合的角度建立了公路网服务水平评价指标体系。考虑到单一的主、客观评价方法的不足和评价指标的不同重要程度,采用AHP与熵值法相结合的组合赋权方法确定指标权重,提出了加权灰色相似关联度评价模型,从而建立了基于组合赋权和灰色相似关联度的区域公路网服务水平综合评价方法。以宁波市5个地区的公路网为例,对综合评价方法进行了应用,得到服务水平由高到低的排序为鄞州区、余姚市、奉化市、象山县、宁海县,对应的评价值分别为0.944,0.873,0.819,0.815、0.778,评价结果与实际情况相吻合。     

城市轨道交通站台自动扶梯服务水平研究

通过对西安市地铁2号线钟楼站晚高峰时段,站台至站厅层上行扶梯进行的人工观测与视频采集,在自动扶梯处区域划分及行人特性分析基础上,得到速度-密度拟合曲线。以人均占据面积为标准得出适用于西安市城市轨道交通的自动扶梯服务水平分级。结果表明,本分级方案对我国城市轨道交通站点运营中的实际情况具有较强的针对性,并具有一定的理论意义和实用价值。     

基于遗传BP网络的城市空气质量等级预测

针对空气污染诱因复杂、影响机理非线性等特点,选用遗传BP网络,对城市空气质量等级进行短期预测.分别使用2类共10种方案对数据进行了关联,使用遗传算法对输入变量进行了筛选,对BP网络的网络结构、权值和阀值进行了优化.仿真结果表明,经优化后的BP网络对未来8天空气质量等级的平均预测正确率达67.1%.     

Numerical simulation of viscous liquid sloshing by moving-particle semi-implicit method

A meshless numerical simulation method, the moving-particle semi-implicit method （MPS） is presented in this paper to study the sloshing phenomenon in ocean and naval engineering. As a meshless method, MPS uses particles to replace the mesh in traditional methods, the governing equations are discretized by virtue of the relationship of particles, and the Poisson equation of pressure is solved by incomplete Cholesky conjugate gradient method （ICCG）, the free surface is tracked by the change of numerical density. A numerical experiment of viscous liquid sloshing tank was presented and compared with the result got by the difference method with the VOF, and an additional modification step was added to make the simulation more stable. The results show that the MPS method is suitable for the simulation of viscous liquid sloshing, with the advantage in arranging the particles easily, especially on some complex curved surface.     

枢纽下游水位降落问题探讨

根据有关文献报道,对国内外部分已建枢纽坝下河床调整及水位降落情况进行了综述。分析了影响河床调整的主要因素以及河床调整与水位降落的关系,提出了防止水位降落影响通航水流条件的治理措施。     

Dynamics of suprabenthos-zooplankton communities around the Balearic Islands (western Mediterranean): Influence of environmental variables and effects on the biological cycle of Aristeus antennatus

Dynamics of suprabenthos and zooplankton were analyzed in two areas located in the NW (off Sóller harbour) and S (off Cabrera Archipelago) of Mallorca (Balearic Islands, western Mediterranean) at depths ranging between 135–780 m. Four stations situated respectively at 150 m (shelf-slope break), and at bathyal depths of 350, 650 and 750 m were sampled at bi-monthly intervals during six cruises performed between August 2003 and June 2004. Suprabenthos showed maximum biomass in both areas from late spring to summer (April to August), while minimum biomass was found in autumn (September–November). Though variable, temporal dynamics of zooplankton showed peaks of biomass in late winter and summer (February and June), while minimals occurred in autumn (August–September) and, at bathyal depths, in April. Suprabenthos (abundance; MDS analyses) showed a sample aggregation as a function of depth (3 groups corresponding to the shelf-slope break, upper slope — over 350 m; and the middle, deeper part of the slope — over 650–750 m), without any separation of hauls by season. By contrast, zooplankton samples were separated by season and not by depth. There was evidence of three seasonal groups corresponding to summer (June 2004–August 2003), autumn–winter (September and November 2003, February 2004), and spring (April 2004), being especially well established off Sóller. In general, suprabenthos was significantly correlated with the sediment variables (e.g. total organic matter content (% OM), potential REDOX), whereas zooplankton was almost exclusively dependent on Chl a at the surface, which suggests two different food sources for suprabenthos and zooplankton. The increase of suprabenthos abundance in April–June was paralleled by a sharp increase (ca. 2.8 times) in the %OM on sediment during the same period, coupled ca. 1–2 months of delay with the peak of surface Chl a recorded in February–March (from satellite imagery data). Suprabenthos biomass was also correlated with salinity close to the bottom, suggesting a link between suprabenthos abundance and changes in the oceanographic condition of water masses close to the bottom. It is suggested that a higher suprabenthos biomass recorded off Sóller in comparison to that off Cabrera in June could, in turn, be related to a seasonal inflow of Levantine Intermediate Water (LIW) in April–June in this area at mid bathyal depths (350–650 m). This trend would be based on: 1) it was evident only at mid-slope depths between 350–750 m, coinciding with the LIW distribution, and 2) it was not recorded among zooplankton (collected throughout the water column). The possible effect of the fluctuations of suprabenthos and zooplankton on higher trophic levels has been explored studying the diet and food consumption rates of the red shrimp Aristeus antennatus, as indicator species by its dominance in bathyal communities. A. antennatus increased its food consumption from February to April–June 2004 off Sóller, which in the case of large (CL > 40 mm) specimens was found in both areas. In addition, there was a shift of diet from winter to spring–early summer. In this last period, A. antennatus preyed upon euphausiids and mesopelagic decapods and fish, while benthos (e.g. polychaetes and bivalves) decreased in the diet. This indicates an increase in the food consumption and probably in the caloric content of the diet in pre-spawning females in April–June 2004, which is synchronized with the period when gonad development begins in A. antennatus females (May–June). Anyway, macrozooplankton, and not suprabenthos, is crucial as a high energetic food source in the coupling between food intake and reproduction in the red shrimp.     

基于CS5460A的直流电力机车专用智能电度表系统

基于机车电度表的现状，结合芯片CS5460A，主要从硬件方面介绍了一种全电子式电力机车直流电能记录系统的技术原理，分析了该系统的隔离安全方面设计。该系统实现了机车用电、线网电压、线网电流的准确计量，同时为电力机车用电的科学管理打下了基础。     

浅谈低液限粉（黏）土路基强夯法处理

本工程为低液限粉(黏)土路基的强夯法处理。通过强夯试验确定具体施工参数。本工程的强夯施工,达到了提高低液限粉(黏)土路基的强度和降低压缩性之目的。强夯法是成本低、速度快、技术较为可靠的地基处理方法。     

作战模拟训练系统中导调框架的设计

导调系统是模拟训练系统中必不可少的部分,是确保训练正常有序运行、实现人与系统交互的关键.通过设计构建导调系统框架,对其基本功能,体系结构、运行流程进行说明,并对主要功能模块及关键技术的实现方案作了详细分析.此框架具备一定的通用性,可以在多个层次的作战模拟训练系统中得到应用,可提高系统开发效率.