南沙龙穴造船基地水下大砂袋封涌施工

介绍南沙龙穴造船基地深水河涌水下大砂袋封截的施工经验。     

The association of the population recruitment of gulf menhaden, Brevoortia patronus, with Mississippi River discharge

Gulf menhaden, Brevoortia patronus, which constitutes a major industrial reduction fishery in the USA, spawn across the northern Gulf of Mexico with a focus of spawning about the Mississippi Delta. This species is estuarine dependent; adults spawn over the continental shelf and their larvae are transported, by mechanisms that are presently not well understood, to estuarine nursery areas. Larval gulf menhaden, along with some other surface oriented larval fishes, appear to aggregate along the Mississippi River plume front, while evidence of the ecological consequences of this aggregation in terms of the feeding, growth, and survival of larvae is ambiguous. On an annual scale, Mississippi River discharge is negatively associated with numbers of half year old recruits. Discharge of the Mississippi River and the population recruitment of gulf menhaden may be plausibly linked through the action of the river's plume and its front on the shoreward transport of larvae. Greater river discharge results in an expansive plume that might project larvae farther offshore and prolong the shoreward transport of larvae. An indirect, decadal scale, positive response of recruitment and river discharge is possible, but not certain. Recruitment became elevated after 1975 when river discharge increased and became highly variable. This response might owe to enhanced primary and secondary production driven by nutrient influx from the Mississippi River.     

On the fresh balance of the Adriatic Sea

The long-term mean fresh water balance of the Adriatic Sea is studied by ananalysing evaporation, precipitation and river runoff. Evaporation is computed from May latent heat flux and by means of bulk formula. In the latter case two wind speed data sets are used, namely those from the NMC and May. The sea surface temperature is taken from a historical Adriatic data set, and the air temperature and relative humidity come from the NMC data set. Two precipitation data sets are considered, namely the Legates and Willmott climatology and a data set consisting of data measured at 62 rain-gauge stations located on the Adriatic coasts. Runoff contribution to the fresh water balance is estimated from the long-term average flow rates of 39 rivers and the horizontal distribution of salinity in the upper mixed layer.The spatial distribution of the fresh water balance, as well as of its components, is analysed by means of monthly objective maps, from which averages and standard deviations are computed. The results obtained from the different computations are not always univocal, particularly in the evaluation of Summer evaporation, and are affected by relatively large statistical errors. Significant spatial and seasonal variability occurs, with a noticeable fresh water gain along the coastline of the northern and middle basins, while small areas of fresh water loss are found in the middle and southern basins. Nevertheless, on an annual basis, the difference between the fresh water losses by evaporation and the gains by precipitation and runoff is clearly negative, indicating that, unlike the whole Mediterranean, the Adriatic Sea is generally a dilution basin.     

江苏省沿江城市群城际轨道交通线网规划方案研究

城际轨道交通的规划建设是城市群发展的必然要求,江苏沿江城市群是我国城市化进程过程中重点发展的区域。根据沿江地区城市群的特征,把沿江地区城际轨道交通线网分为主骨架城际网和都市圈城际网两个层次进行规划,重点研究沿江地区都市圈内部中心城市之间以及中心城市与中小城市之间的城际轨道交通通勤线网。     

轿车覆盖件拉延动态仿真及成形性分析

结合丰田轿车前围板拉延成形过程的数值模拟，探索了轿车覆盖件拉延成型数值模拟的一般过程。利用ETA／DYNAFORM软件对前围板进行了拉延过程的模拟，针对压边力、凸凹模圆角、拉深筋设置及坯料形状进行了优化设计，消除了拉裂及起皱现象，提出了模拟过程中应注意的问题及解决方法。     

大跨度钢箱梁斜拉桥中跨合龙关键技术

以4座主跨超过400 m的钢箱梁斜拉桥中跨合龙控制为背景,对大跨度钢箱梁斜拉桥中跨合龙的2种方法进行对比分析,对合龙各主要工序的关键技术进行研究。提出了合龙段配切长度的计算公式和合龙口宽度连续观测的测点布置方式。建议:在调整好合龙口姿态后可不加压重,也可不采用临时劲性骨架锁定;采用无线采集设备采集合龙口结构的温度场,用激光测距仪测量合龙口宽度以提高观测效率和安全性;在悬臂施工阶段关注梁长累计误差并通过调整后续梁段的制造长度消除之。     

桥梁转体施工自闭合式合龙钢壳系统及施工技术研究

为进一步减小转体施工桥梁合龙施工时对既有运营线路的干扰,同时解决传统钢壳法中加劲肋板对合龙段施工的影响,以首座采用墩中转体的大树村龙川江三线大桥为依托,在传统钢壳法的基础上进行优化研究,自行研制、设计了一套自闭合式合龙钢壳系统并应用于实践,最终达到了安全、优质、快速、有序合龙的目的。实践结果表明,自闭合式合龙钢壳系统能够满足施工要求,且使用效果良好,达到了优化施工的目的,可为类似桥梁合龙施工提供参考。     

中越界河海事执法行为的风险规避

文中通过介绍中越边境河流——北仑河海事现场执法风险，分析执法风险存在的原因、表现形式，结合实际工作体会，探讨界河基层海事执法的风险防范     

潮位变化对上海某越江盾构隧道变形的影响规律研究

为了探究潮位变化与越江盾构隧道的沉降和收敛变形之间的关联性,采用数据统计分析、相关性分析和周期性分析方法,对上海某越江盾构隧道的监测数据与同时期隧道上部的潮位变化进行研究分析。研究表明:1)江中段隧道在潮位变化的作用下产生均匀沉降,其波动性与潮位起伏具有近似的周期性;2)陆域段隧道沉降变化的波动性程度与河流的距离有关;3)潮位变化引起隧道管片断面的横径和竖径产生循环的收敛变形,其横径收敛变形大于竖径收敛变形。以上研究可为越江盾构隧道设计、施工和运维提供参考。     

超级电容渡船——城市内河交通新构想

提出了一种将超级电容与渡船相结合的构想,通过对超级电容的特性和渡船航行特点的介绍,诠释了超级电容渡船的内涵,并在这个基础上对其可行性及实用性进行了分析,具有一定的参考价值。