Large-scale physical controls on phytoplankton growth in the Irminger Sea Part I: Hydrographic zones, mixing and stratification

Hydrographic surveys in three consecutive seasons in the Irminger Sea in 2001/2002 have revealed six physical regimes (zones) in which different surface mixing and spring re-stratification processes dominate. They are the South Irminger Current, the North Irminger Current, the Central Irminger Sea, the Polar-origin East Greenland Current, the Atlantic-origin East Greenland Current and the Reykjanes Ridge. The variations in restratification processes in particular have significant implications for the timing of shallow spring mixed layer development and therefore the timing and strength of the spring bloom. The relative roles of heat and freshwater in controlling re-stratification are examined for each hydrographic zone, and it is shown that the simplest concept of solar warming generating spring stratification is appropriate for the Irminger Current and the central Irminger Sea. However in the East Greenland Current and the Reykjanes Ridge zones, the springtime arrival of fresh or saline water at the surface dominates re-stratification and generates the earliest and strongest spring blooms of the region. In the cool fresh centre of the Irminger Sea the relatively low chlorophyll-a throughout the year cannot be wholly explained by stratification or nutrient concentrations. Details of the annual cycle in temperature, salinity, chlorophyll-a and nutrients are presented for each hydrographic zone.     

区域旅游交通小区划分研究

为对旅游交通小区进行准确划分,必须先对旅游交通的研究范围和对象进行准确界定。通过对旅游交通特性的分析,了解到旅游交通与公共交通的主要区别体现在:时空的不均衡性,较强的时效性,较高的娱乐性、享乐性。对比城市交通小区的划分,提出区域旅游交通小区的划分原则和步骤,并利用这些原则和步骤,对云南省旅游交通小区进行划分,验证原则和步骤的实用性。     

朝阳市珠江斜拉桥索梁锚固区应力分析

以朝阳市珠江桥为工程背景,通过大型结构分析程序midas civil2006进行空间有限元分析,得出了斜拉索主梁锚固区的实际受力情况,为桥梁的设计和施工提供了可靠的依据。     

江西省沥青路面使用性能气候分区

根据江西省各气象站点1979～2008年近30年的气象数据资料,采用适合江西省气候条件的高温指标、低温指标和雨量指标,将江西省沥青使用性能分为4个温度分区、8个气候分区,并分别绘制了江西省沥青路面使用性能高温分区图、低温分区图及雨量分区图。     

琴桥桥塔拉索锚下锚固区局部应力分析

大连开发区琴桥是1座主跨度112m的独塔竖琴式单索面单背索斜拉桥,该桥主塔结构形式独特,背索的索塔锚固区受力复杂。采用ANSYS程序中的空间块体单元,对该桥塔背索锚固区下的区域进行局部应力分析计算,并通过光弹模型试验,与计算结果进行对比分析,为设计提供依据,对同类型的桥梁设计有一定的设计参考价值。     

湖南省公路沥青路面气候影响分区方案研究

比较国内、外几种主要的沥青路面气候影响分区方法,在统计分析湖南省气候特点的基础上,确定影响湖南省公路沥青路面选材的模型和相关因子,从空间基础数据库中优选湖南省公路沥青路面气候影响模型、降雨-气温指数和降雨-冰冻指数模型,确定湖南地区公路沥青路面气候影响三级分区的方法和步骤.     

交通态势识别及状态转换机制研究

利用驾驶员的认知拓扑生成动态交通态势图,以克服驾驶员视野盲区的缺陷,可进一步避免交通事故的发生,为交通运输系统和智能车辆系统的仿真研究和实物开发提供理论指导与技术支持.     

An overview of maintenance management strategies for corroded steel structures in extreme marine environments

Maintenance is playing an important role in integrity management of marine assets such as ship structures, offshore renewable energy platforms and subsea oil and gas facilities. The service life of marine assets is heavily influenced by the involvement of numerous material degradation processes (such as fatigue cracking, corrosion and pitting) as well as environmental stresses that vary with geographic locations and climatic factors. The composition of seawater constituents (e.g. dissolved oxygen, salinity, temperature content, etc.) is one of the major influencing factors in degradation of marine assets. Improving the efficiency and effectiveness of maintenance management strategies can have a significant impact on operational availability and reliability of marine assets. Many research studies have been conducted over the past few decades to predict the degradation behaviour of marine structures operating under different environmental conditions. The utilisation of structural degradation data – particularly on marine corrosion – can be very useful in developing a reliable, risk-free and cost-effective maintenance strategy. This paper presents an overview of the state-of-the-art and future trends in asset maintenance management strategies applied to corroded steel structures in extreme marine environments. The corrosion prediction models as well as industry best practices on maintenance of marine steel structures are extensively reviewed and analysed. Furthermore, some applications of advanced technologies such as computerized maintenance management system (CMMS), artificial intelligence (AI) and Bayesian network (BN) are discussed. Our review reveals that there are significant variations in corrosion behaviour of marine steel structures and their industrial maintenance practices from one climatic condition to another. This has been found to be largely attributed to variation in seawater composition/characteristics and their complex mutual relationships.     

低排放区和拥堵收费国际经验

伴随中国快速城镇化与机动化进程，严重的空气污染和交通拥堵造成巨大的社会经济损失，缓堵减排需求迫在眉睫。低排放区和拥堵收费政策在许多发达国家和地区被验证能有效缓堵。首先探讨伦敦、新加坡和斯德哥尔摩3个城市成功实施低排放区和拥堵收费政策的特点和经验。总结成功实施缓堵减排政策的关键要素，包括立法保障与领导意志、公众宣传与信息公开、综合性配套政策、精细化管理以及拥堵收费与低排放区有效结合等。基于此，探索缓堵减排政策在中国的应用实践，总结中国低排放区和拥堵收费的方案设计流程。最后，从法律法规、体制机制、效果评估和公众宣传等方面提出相应的政策建议，以应对缓堵减排政策实施过程中可能遇到的问题与挑战。