杭州湾跨海大桥北航道桥北侧高墩区引桥施工

杭州湾跨海大桥北航道桥及北侧高墩区引桥为杭州湾大桥工程的第Ⅱ合同段。简要分析介绍在杭州湾水域恶劣复杂的水文气象条件下,采用栈桥施工方案的技术经济合理性。     

黄土地区既有铁路基床病害整治加固技术研究

分析了黄土地区既有铁路基床病害类型及产生原因,提出了基床病害防治及整治基本思路和措施,并在宝中铁路防洪加固中进行了应用,取得了较好的技术、经济效果。     

浅谈新型阻尼材料在汽车涂装中的应用

研究了可喷涂液体阻尼材料(Liquid Apply Sound Deadener,LASD)的阻尼性能,涂装机器人喷涂参数、材料施工操作工序等因素对涂装效果的影响。研究结果表明,在-20~50℃区间范围内,LASD的阻尼性能优于铺设热熔型沥青阻尼垫的参比样品,涂装LASD的产品车内降噪表现优于涂装沥青阻尼垫的参比样品。自动喷涂参数方面,采用枪距30~40 cm,预压1.35~2.2 MPa,线速度400~600 mm/s的喷涂参数可以获得膜厚均一稳定的最佳涂装效果。LASD温度在30~40℃区间内施工性能良好,喷涂LASD材料后放置时间过长(≥8 h)会导致材料的开裂,引起阻尼性能下降。     

采用平导超前和无轨运输方式的长大瓦斯隧道施工六阶段通风技术

合理的通风设计是降低隧道长距离穿越煤系地层时所面临的严峻瓦斯灾害风险的重要措施。文章针对成贵高铁老房子隧道长距离穿越高瓦斯地层时的通风难题,设计出一套随施工进度变化可进行调整的先压入后巷道式的六阶段通风方案,并采用Fluent软件模拟分析,最后以实际监测结果进行验证。结果表明,第四阶段通风效果最差,为通风最不利工况,该阶段隧道内瓦斯浓度均未超过0.5%的限值,其它阶段隧道内风流中最大瓦斯浓度为0.08%,所有指标均满足规范的要求。由此可知,六阶段通风方案通风效果良好,可为类似工程设计和施工提供良好的借鉴作用。     

Environmental changes and the responses of the ecosystems of the Yellow Sea during 1976–2000

The changes in the environmental features of the Yellow Sea during the last 25 years of the 20th century were studied using a set of seasonally monitored data along a transect (at 36°N) maintained by the State Oceanic Administration of China. The data included the ocean temperature (T), salinity (S) and biogenic elements, such as dissolved oxygen (DO), phosphorus (PO₄-P), silicon (SiO₃-Si) and dissolved inorganic nitrogen (DIN).The seasonal (summer and winter) values and the annual mean of these elements showed significant changes during the monitored period. Time series of T, S, DIN and N:P ratios exhibited positive trends, while those of DO, P and Si exhibited negative trends. During this period, the annual mean of T and DIN in the Yellow Sea increased by 1.7 °C and 2.95 μmol L⁻¹, respectively, while those of DO, P and Si decreased by 59.1, 0.1 and 3.93 μmol L⁻¹, respectively. In the 1980s, particularly in between 1985 and 1989, concentrations of P and Si dropped to near the ecological threshold for growth of diatoms. The N:P ratio increased from 4 in 1984 to over 16 in 2000. The climate trend coefficients, R_xt, for these time series are all above 0.43 with significance levels of 95%, except for salinity. The increases in T were consistent with the recent climate warming in northern China and the adjacent seas, i.e. the Bohai Sea and the East China Sea. The reduction of DO was probably attributable to the increase in T and decrease in primary production in these regions. The positive trend of DIN was mainly attributable to precipitation and partly to Changjiang River discharge. The negative concentration trends of P and Si were due to the decreases in their concentrations in seawater that flowed to the Yellow Sea from the Bohai Sea. As a result, N:P ratios greatly increased in the seawater of the Yellow Sea.Moreover, some important responses of the Yellow Sea ecosystems to the changes in physical variables and chemical biogenic elements were obviously displayed. These responses include strengthening nutrient limitation, decreasing chlorophyll a, primary production and phytoplankton abundance, succession of dominant phytoplankton species from diatoms to non-diatoms, changes in fish community structure and species diversity.     

新世纪中国航运业的新发展

今天，我很高兴来到上海参加第12届中国国际海事学术会议，与中外海运界的各位朋友一道，共同交流海运业及相关产业的发展状况与趋势，探讨促进海运业持续健康发展的政策措施。此次会议，是我国在本世纪初迎来的又一次中外航运业界的盛会，预祝大会取得圆满成功。     

润滑状态可靠性对磨损的影响

本文根据摩擦副润滑状态可靠性和接触概率的计算新方法,结合弹流润滑状态图,编制了通用的计算程序,并利用该程序计算了弹流润滑中点。线接触时的可靠度及接触概率,从而定量地分析了主要工况参数对之的影响,文中通过磨粒摩损试验,进一步阐明了可靠性和接触概率与磨损量的关系。     

银屑病表皮中增殖细胞抗原与转化生长因子－α的表达水平

应用免疫组化技术检测４８例寻常性银屑病表皮角朊细胞中增殖细胞核抗原（ＰＣＮＡ）、转化生长因子（ＴＧＦ－α）的表达水平，结果发现二者在银屑病皮损处角朊细胞中的表达水平（阳性细胞数目和着色）都有不同程度升高。经统计学处理与正常对照组相比，ＰＣＮＡ无显著性差异，但因在免疫染色中ＰＣＮＡ有１／３的假阴性，故尚不能轻易否定ＰＣＮＡ在银屑病发生发展中的作用；ＴＧＦ－α确有显著性差异，并发现角朊细胞中ＴＧＦ－α的表达丰度与该处病变的严重程度呈正相关。     

强夯处理红粘土的质量控制

基于红粘土特殊的工程特性和水文特性,结合机场建设的施工要点,在总结国内外的施工技术经验上,采用强夯技术处理红粘土,并探讨了强夯施工时应注意的关键技术要点、监理控制措施以及必要的安全措施。     

基于法线偏差的旧路平面线形拟合精度评估方法

在论述拟合法线偏差定义、构成及性质的基础上,提出以拟合法线偏差表征旧路平面线形拟合偏差;建立了基于法线偏差的旧路平面线形拟合精度指标;提出了采用步长压缩摆动趋近法计算拟合法线偏差的算法,并就拟合法线偏差的符号判定准则及方法进行了讨论。最后对321国道某路段旧路改造设计中的平面线形拟合精度进行评估。结果表明:按照外业、内业2个阶段,采用拟合精度指标控制旧路平面线形拟合质量是可行的。