论经济地理研究中的运输化问题

本文提出运输化是工业化的重要特征,也是伴随工业化而发生的一种经济过程,经济发展的运输化过程受一定客观规律的支配。应当重视运输化进程与生产力布局、经济空间结构改善之间的关系,把对不同区域运输化发展水平及运输化进一步走向的分析,与经济发展规划结合起来。     

港口与腹地供应链的协同效应分析

物流成本是影响地区贸易发展的重要因素,而腹地运输则是物流成本结构中比重最大的组成部分,因此,腹地运输效率的改善能够有效提升区域间的贸易活跃度。结果显示,公路运输价格的波动对供应链总运量具有短期效应,而铁路运输价格和港口装卸价格则表现出更多的外生性。同时,物流服务价格的提高会减少厂商在该腹地的货运总量,但物流服务提供商的规模以及服务的可靠性能够有效地降低运量对价格的敏感程度。     

中国将建设内蒙古东部新的煤炭出海南下大通道

新华社沈阳消息 在中国煤炭运输大港秦皇岛港附近的绥中县,将崛起一座新的亿吨级煤炭港区。这个新煤炭港区将成为辽宁省最大的煤炭运输港口,为内蒙古东部的煤炭资源出海南下提供支撑。     

基于熵的瓶颈运输问题的动态规划解

建立了关于时间(路程)的瓶颈运输问题的动态规划模型,并利用熵作为工具,解决了物品运输过程中所用时间长短的界问题,进而给出易于处理的瓶颈运输问题的动态规划模型。最后给出一个实例说明该方法的实用性和有效性。     

考虑东北航线的亚欧LNG运输发展潜力研究

北极海冰的加速消融为北极航线的开发利用带来了机遇,北极地区的经济价值凸显。北极东北航线为亚欧间的LNG运输提供了新的运输通道。为使亚欧间的LNG运输更为经济合理,基于海运里程和单船必要运费率两方面比较通过北极东北航线、苏伊士运河航线、好望角航线进行跨亚欧LNG运输的经济性。在此基础上,采用负指数网络配流方法计算不同路径的配流比例,研究东北航线的亚欧间LNG运输发展潜力。结果表明,整体而言,采用东北航线进行跨亚欧LNG运输的海运里程更短,单船必要运费率更低,配流比例更高,其中,日本袖浦使用东北航线的经济性最为显著。将跨亚欧LNG运输通道的经济性分析和交通分配相结合,为亚洲地区更为经济合理地进行LNG运输提供参考。     

内蒙古将新建煤运通道 直达湘鄂赣

"十二五"期间,国家将规划建设蒙西至华中地区的北煤南运运输通道,以解决煤运难题。记者从内蒙古自治区发改委了解到,日前,蒙西至华中地区铁路煤运通道工程预可研审查会在北京召开,内蒙古自治区发改委铁路办参加了会议,原则同意设计部门提出的内蒙古自治区境内线路方案。内蒙古自治区代表认为,该项目     

Sources and transport of organic carbon from the Dongjiang River to the Humen outlet ofthe Pearl River,southern China简

Transport of organic carbon via rivers to estuary is a significant geochemical proc- ess in the global carbon cycle. This paper presents bulk total organic carbon （TOC） from the Dongjiang catchment to the adjacent Humen outlet, and discusses the applicability of 613C and ratio of carbon to nitrogen （C/N） as indicators for sources of organic matter in the surface sediments. Survey results showed that organic carbon concentration in summer were higher than in the winter. An elevated trend of TOC occurred along the river to the Humen outlet in both surveys, and the highest mean values of dissolved and particular organic carbon （DOC-279 μmol L-1 and POC-163μmol L-1） were observed in the urban deltaic region in summer flood flow. Winter samples had a wide range of b＇13C and C/N （5-3C -24.6%o to -30.0%o, C/N 4-13）, and summer ones varied slightly （8-3C -24.2%o to -27.6%0, C/N 6-18）. As results suggest that POC in the three zones of upstream-delta-outlet dominantly came from riverbank soil, phytoplankton and agricultural C3 plants in winter, whereas main sources were from the riverbank and mangrove soil in summer. Moreover, anthropogenic sewage inputs had 11% and 7% contribution to POC in the deltaic and outlet. Transport accompanied with seasonal freshwater variation, phytoplankton production and degradation, and removal be- havior caused variation of organic carbon concentration. The results also discovered that TOC export bulk in Dongjiang was approximately one quarter of Humen flux in the dry flow, and anthropogenic activity significantly impacted the river export contribution.     

Impact of the water-sediment regulation and a rainstorm on nutrient transport in the Huanghe River

Dissolved nutrient concentration in the Huanghe(Yellow) River at Lijin was monitored during a water-sediment regulation period and a subsequent rainstorm from 14 June to 19 July, 2005. This study provides detailed information on nutrient concentrations in the Huanghe River during the water-sediment regulation and rainstorm periods, and is of signifi cance for the downstream area of the Huanghe River and the Bohai Sea. The average concentrations of nitrate, nitrite and ammonia were 304.7 μmol/L, 0.19 μmol/L, and 1.10 μmol/L, respectively, while the average concentrations of dissolved inorganic phosphorus(DIP) and dissolved silicate(DSi) were 0.23 μmol/L and 122.9 μmol/L, respectively. Nutrient concentrations during the water-sediment regulation period were mainly infl uenced by the dilution effect, fl oodplain effect and sediment resuspension while dilution and erosion effects were the main factors during the rainstorm. The fl uxes of dissolved inorganic nitrogen(DIN), DIP and DSi during the water-sediment regulation and rainstorm periods accounted for 20.4%, 19.5%, 16.7% and 4.97%, 6.45%, 5.47% of the annual nutrient fl uxes, respectively. Discharge was the main factor infl uencing the fl uxes of nutrients during both the watersediment regulation and the rainstorm periods.     

密度胁迫对卵形鲳鲹鱼苗运输水质、存活率、免疫酶活力和血清指标的影响

为了研究密度胁迫对卵形鲳鲹(Trachinotus ovatus)鱼苗运输水质、存活率、免疫酶活力和血清生化指标的影响,确定适宜的运输密度,为卵形鲳鲹鱼苗的科学运输提供参考依据。对卵形鲳鲹鱼苗(体长为5.36cm±0.60cm,质量为3.04g±0.71g)采用塑料袋密闭充氧运输方式,在3个不同运输密度下(D1=9 kg/m~3、D2=12 kg/m~3、D3=15 kg/m~3)模拟运输8 h,对比运输不同密度卵形鲳鲹鱼苗对运输水质、鱼苗存活率、肝脏免疫酶活力和血液生理生化指标的影响程度。结果表明, 3个密度组的卵形鲳鲹鱼苗的存活率均为100%,经运输后暂养72 h的存活率仍为100%。经塑料袋密闭充氧运输8 h后, 3个密度组的运输水体的DO含量无显著变化,运输水体温度(T)和pH值随运输密度的增加而降低, NH_4-N含量随运输密度的增加而上升,其中NH_4-N的含量显著高于对照组。肝脏组织中, D1、D2、D3的总超氧化物歧化酶(T-SOD)活力无显著差异(P0.05,下同),而高运输密度组(D3)对比对照组,两组的T-SOD活力变化存在显著差异(P0.05)。密度运输胁迫组乳酸脱氢酶(LDH)活力显著高于对照组水平,D2、D3无显著差异,显著差异于D1组。过氧化物酶(POD)活力D1、D2、D3组无显著差异,但均显著低于对照组。3组实验组的过氧化氢酶(CAT)活力均显著高于对照组且组间无显著差异。血清中, D1、D2组的CRE活力显著低于对照组,但D3组又显著高于对照组。D1、D2、D3的血清中皮质醇(COR)活力无显著差异,但显著高于对照组。D2、D3的葡萄糖(GLU)含量与对照组无显著差异, D1显著低于对照组。D1、D2、D3 3个运输密度组的谷丙转氨酶(GPT)与谷草转氨酶(GOT)活力均显著高于对照组。同时, D1与D2组的GPT活力显著低于于D3组,但GOT活力显著高于D3组。密度胁迫对卵形鲳鲹鱼苗的运输存活率无影响,但对运输其的水质、免疫酶活力及血清生化指标均有影响。在实际运输中,采用塑料袋密闭充氧运输,运输时间时长为8 h以内,运输密度设定为15 kg/m~3的卵形鲳鲹鱼苗为宜。     

中日海运发展动向

进入80年代末(90年代初),世界经济区域化、国际贸易集团化取得了明显进展,同时国际分工越来越细,国际间贸易摩擦不断扩大。为减少乃致避免与美国和欧洲的贸易摩擦,日本不得不重新考虑其经济发展战略,从“脱亚入欧”转为“脱欧入亚”,为中日贸易迅速发展提供了前提条件。据中国海关统计1993年1～8月份我国对日贸易高达211亿美元,比上年同期