粤东某防波堤设计标准探讨

以粤东地区某专用港为例，对防波堤的布置形式及设计标准提出按2年一遇波要素确定防渡堤断面尺寸．在保持港内有较好的泊稳奈件的同时，可以有效控制工程投资。     

100-years-changes in the phytoplankton community of Kiel Bight (Baltic Sea)

Literature data from 1905/06, 1912/13 and 1949/50 were compared with recent data (2001–2003) from Kiel Bight in order to investigate changes in phytoplankton composition and biomass, which may serve as indicators of environmental changes. In terms of biomass, diatomophyceae and dinophyceae are by far the most important groups. Their ratio is still close to unity. The share of diatomophyceae increased strongly in years with exceptionally high summer blooms (2001) or exceptionally early spring blooms (2003). The summer and autumn blooms of Chaetoceros and Skeletonema, detected in the early 20th century, are replaced by other diatoms (Cerataulina pelagica, Dactyliosolen fragilissimus, Proboscia alata, Pseudo-nitzschia spp.). Chaetoceros and Skeletonema are still important components of the spring blooms. Now as before, the autumn blooms are dominated by Ceratium spp., sometimes also by diatoms. Newly appearing bloom-forming species are mostly potentially toxic (Dictyocha speculum, Prorocentrum minimum, Pseudo-nitzschia spp.). The total phytoplankton biomass has roughly doubled in the course of the last century. The reference condition for phytoplankton biomass in Kiel Bight in the sense of the Water Framework Directive was defined at 55 mg C m^− 3 (± 10%, annual mean). The mean annual biomass of diatomophyceae and dinophyceae was 25 mg C m^− 3 (± 40%) for each, indicating that the sum of their carbon biomass amounted to 90% (± 10%) of the total phytoplankton biomass on an annual average. Diatomophyceae represented at least 80% of carbon biomass in the spring bloom peak at the beginning of the 20th century.     

青藏铁路修筑后次生不良冻土现象的特征及发展趋势

青藏铁路的修建会形成次生不良冻土现象,次生不良冻土现象会对铁路产生诸多危害。研究青藏铁路修筑以后次生不良冻土现象的特征及发展趋势意义重大。对青藏铁路沿线不同类型的次生不良冻土现象进行调查研究,研究青藏铁路修筑以后次生不良冻土现象产生的机理、发育特征及发展趋势。查明对青藏铁路有直接或潜在威胁的次生不良冻土现象18处,其中与路基有关的次生不良冻土现象较少;与桥梁有关的次生不良冻土现象,主要是桥下形成冰椎、冰幔等;与涵洞有关的次生不良冻土现象,主要有涵洞下沉等。研究表明:未来气温升高导致多年冻土上限附近地下冰大量融化,将会产生诸多次生不良冻土病害,影响铁路的正常运营。     

Using topology and neighbor information to overcome adverse vehicle density conditions

Vehicular networks supporting cooperative driving on the road have attracted much attention due to the plethora of new possibilities they offer to modern Intelligent Transportation Systems. However, research works regarding vehicular networks usually obviate assessing their proposals in scenarios including adverse vehicle densities, i.e., density values that significantly differ from the average values, despite such densities can be quite common in real urban environments (e.g. traffic jams). In this paper, we study the effect of these hostile conditions on the performance of different schemes providing warning message dissemination. The goal of these schemes is to maximize message delivery effectiveness, something difficult to achieve in adverse density scenarios. In addition, we propose the Neighbor Store and Forward (NSF) scheme, designed to be used under low density conditions, and the Nearest Junction Located (NJL) scheme, specially developed for high density conditions. Simulation results demonstrate that our proposals are able to outperform existing warning message dissemination schemes in urban environments under adverse vehicle density conditions. In particular, NSF reduces the warning notification time in low vehicle density scenarios, while increasing up to 23.3% the percentage of informed vehicles. As for high vehicle density conditions, NJL is able to inform the same percentage of vehicles than other existing approaches, while reducing the number of messages up to 46.73%.     

道路交通救援点条件覆盖选址策略及评价

在改善道路交通救援服务质量的过程中，救援点的选址是一项重要工作。现有救援点的布局对选址结果具有重要影响。建立选择性的保留现有救援点的双层条件集合覆盖——p-中值模型。通过参数的连续变动，得到一组条件覆盖-p中值选址方案。基于层次分析法，建立选址结果评价体系，为方案的比选提供依据。结合算例分析，表明该方法的可行性与实用性，可以作为成本约束条件下改善道路交通救援服务水平的依据。     

影响学生参与英语课堂活动的因素

对影响学生参与英语课堂活动的各种因素进行了详细分析,对找出激发与提高学生参与英语课堂活动的对策有重要意义。     

城市复杂环境下的爆破施工

本文主要介绍了深圳蛇口工业区SCT二期陆域形成开山填海工程的爆破施工情况,提出了一些在城市复杂环境下爆破震动、爆破飞石、滚石等防治措施,对类似工程有一定的参考价值。     

水运工程设计与施工条件的相互关系

近十年来,我国水运工程发展迅猛,在优良岸线资源日趋减少和船舶大型化发展的环境条件下,水运工程发展凸现出深水化、外海化的趋势,有关单位相继建造购置了大量的大型高效率施工船舶和设备。在此背景下,水运工程设计的发展需要以新材料、新工艺和新型施工船机等施工条件在工程中的广泛应用作为依托,而施工条件的迅速发展及在工程中的应用又为水运工程设计的进步创造了基础条件。水运工程设计与施工条件相互促进,协调发展,共同促进了我国水运行业建设的健康发展。     

螺栓联接的可靠性研究

本文针对螺栓联接的可靠性,从结构形式、受力分析、预紧力、拧紧力矩等方面介绍了螺栓联接的设计计算方法,分析了装配过程中螺栓联接的影响因素,给出了质量保证方法。     

自动变速器技术状况对稳态工况法检测的影响分析

基于稳态工况法特点和自动挡车辆排气污染物超标现状,分析了自动变速器技术状况对稳态工况法检测的影响,指出在排气污染物超标车辆治理实践中应注重自动变速器的检查与性能恢复,对制定针对性的预防和治理措施具有指导意义。