上海片内非通航河道跨河桥梁梁底高程研究

上海地处太湖流域下游,地区河网密集,地势低洼,跨河桥梁数量众多。由于上海地区地势低洼,桥梁工程梁底高程控制往往与桥梁接坡之间存在较大的矛盾。通过综合分析片内非通航河道行洪安全、规划堤顶高程、作业船舶通行等方面的需求,根据河道等级提出桥梁梁底高程优化取值建议。以长宁区为例,分析该区桥梁梁底高程合理取值范围,为区域桥梁梁底高程控制提供一定参考。     

DS6-K5B型信号区域计算机联锁系统技术及开通维护

系统的介绍了DS6-K5B信号区域计算机联锁系统的系统结构、功能及关键技术,叙述该系统上道开通试验的过程,有针对性的制定区域联锁设备开通后的维护管理。     

黄土地区无砟轨道路基变形与稳定性分析

研究目的:探讨解决在黄土地区尤其是湿陷性黄土地区修建无砟轨道客运专线时路基变形的监测、预测沉降、路基稳定性评判问题,为指导黄土地区路基设计、施工和沉降监控提供建议及依据。研究结果:分析得出路基变形的主要因素,提出了复合地基桩一土“综合模量“的概念以及沉降量的计算方法,对路基稳定性进行了判定,解决了黄土路基的工后沉降技术问题。     

太焦高铁长治南站站前广场及配套附属设施建设项目 设计方案研究

太焦高铁是中国高速铁路网"八纵八横"主通道中"呼南高铁"的重要组成部分,长治南站的开通将结束上党区不通高铁的历史.以太焦高铁长治南站站前广场及配套附属设施建设项目为例,论述在丘陵黄土地区,如何解决进出站旅客换乘、周边配套路网联通、山洪水排泄出路及广场景观亮化提升等问题.目前该工程正在建设,有关经验可供相关专业技术人员参考.     

唐山港京唐港区建设科技创新综述

详细介绍在唐山港京唐港区建设过程中,始终从工程实际出发,研究应用技术,用科技创新指导建港,取得了显著技术成果与经济效益。     

电力机车间接转矩控制中磁链观测器的研究

传统的直接转矩控制算法,限制了电力机车在低速段的控制性能。文章首先介绍了一种基于定子磁链定向的间接转矩控制算法,在此基础上研究了一种新型混合模型闭环磁链观测器,与传统磁链观测器相比,它有效减小了电流和转矩的波动,降低了电流谐波的含量,提高了电力机车的控制性能。最后在4 kW电机实验平台上进行了实验验证,实验结果证明了该方法的合理性和有效性。     

半刚性基层沥青铺面结构在集装箱港区道路中的应用

将半刚性基层沥青铺面结构应用于上海外高桥集装箱港区道路,在国内尚属首创。针对港区道路的特点,结合上海地区水文、地质和建材供应条件及港区生产使用功能要求,通过调查分析和总结集装箱港区已建类似工程道路铺面结构使用情况,分析论证相关施工技术方案,并进行必要的试验,对于半刚性基层沥青铺面结构在应用过程中遇到的各种技术问题,提出了较系统的处理办法。     

Phytoplanktonic nutrient utilisation and nutrient signature in the Southern Ocean

The separation in Southern Ocean provinces of silicate excess at nitrate exhaustion and of nitrate excess at silicate exhaustion was already introduced by Kamykowski and Zentara (Kamykowski, D., Zentara, S.J., 1985. Nitrate and silicic acid in the world ocean: patterns and processes. Mar. Ecol. Prog. Ser. 26, 47–59; and Kamykowski, D., Zentara, S.J., 1989. Circumpolar plant nutrient covariation in the Southern Ocean: patterns and processes. Mar. Ecol. Prog. Ser. 58, 101–111) and our investigations of the silicate to nitrate uptake ratios confirm the earlier distinction. Oligotrophic antarctic waters mainly exhibit proportionally higher silicate removal what induces a potential for nitrate excess. The nitrogen uptake regime of such areas is characterised by low absolute as well as specific nitrate uptake rates throughout. Maximal values did not exceed 0.15 μM d⁻¹ and 0.005 h⁻¹, respectively. Corresponding f-ratios ranged from 0.39 to 0.86. This scenario contrasts strikingly to the more fertile ice edge areas. They showed a drastic but short vernal increase in nitrate uptake. Absolute uptake rates reached a maximum value of 2.18 μM d⁻¹ whereas the maximal specific uptake rate was 0.063 h⁻¹. In addition to an optimal physical environment for bloom development, accumulation of ammonium stimulated nitrate uptake in a direct or indirect way. Since ammonium build-up in surface waters traces enhanced remineralisation, release of other essential compounds during degradation of organic matter might have been the main trigger. This peak nitrate utilisation during early spring led to the observed potential for silicate excess. With increasing seasonal maturity the nitrate uptake became inhibited by the presence of enhanced ammonium availability (up to 8% of the inorganic nitrogen pool), however, and after a short period of intensive nitrate consumption the uptake rates drop to very low levels, which are comparable to the ones observed in the area of nitrate excess at silicate exhaustion.     

临水域软土地区超大深基坑的分区水冲开挖技术初步研究

在软土地区,尤其是在临近水域处,超大深基坑开挖施工可运用水力冲挖法.依次介绍了水冲法的工艺原理、特点、方案、流程,以及设备和人员配置情况.文中以超大深基坑分区后的某单块基坑为例,分析了水冲法和传统机械开挖的效率,测算了经济成本,归纳出可能的技术问题,并提出相应的解决方案.经对比分析可知,水冲法非常适合临近水域的超大基坑的开挖,可应用在诸如大型机场航站楼在内的大型基坑的开挖.