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1.
介绍了株洲建宁大桥的工程概况、技术标准、建设条件,重点论述了大桥的总体布置和主梁、斜拉索、主塔、下部结构的设计以及基础、主塔、主梁的施工方案。分析了该桥的主要技术难点,并提出了相应的处理方法。  相似文献   

2.
选取了能全面表征灌浆料质量的性能参数、有效的试验方法和合适的性能指标;选取了合适的灌浆料专用复合外加剂和水泥。经过试验时比,确定了搅拌方式、搅拌速度、搅拌时间等工艺参数;确定了高性能灌浆料的配合比;配制出了低水灰比、良好可泵性、高体积稳定性、零泌水、高抗氯离子渗透性等优良性能的后张预应力灌浆料;分析了搅拌工艺、水灰比和水泥品种对灌浆料各项性能的影响。  相似文献   

3.
针对三峡库区绿色航运发展的现状及相关需求,阐述了国际航运的现状和发展,对长江航运的现状及发展趋势进行了分析,研究了三峡库区绿色航运的形势、发展机遇及其特点,在上述研究的基础上,指出了推进三峡库区绿色航运存在的主要问题及对策,包括基础设施、运力结构、运输形式、港口物流、三峡旅游、节能减排、航运交易、人才培养等,最后对三峡库区绿色航运作出了展望。  相似文献   

4.
本文运用船舶交通工程学原理,研讨了上海港的海事资料,提出了海损事故自然因素的定量分析公式,对影响海事的自然因素的种类、评判标准、评判方法进行了论述。定量地分析了按月份、时间、星期、农历、流速、风速划分的海事发生系数,定性分析了其它自然因素,提出了减少、预防、预测海损事故的方法和建议。  相似文献   

5.
公元1949年10月1日.中华人民共和国的诞生为华夏历史翻开了划时代的崭新一页!新诞生的共和国坚定、果断地终结了百余年西方列强的掠夺欺凌.废除了丧权辱国的不平等条约.收回了包括海关权、航运权、引航权在内的所有沦丧的国家主权.以自立于世界民族之林的豪迈气概,意气风发地开始了恢复经济和发展经济的伟大征程。经过60年的自力更生、艰苦奋斗,新中国创造了举世瞩目、令人自豪的奇迹,使一个疮痍满目、  相似文献   

6.
凌云集团有限公司是中外合资、横向联合、职工参股、改制上市的综合性母子公司。针对档案人员队伍年轻、兼职多的特点,公司于8月11日至13日在涿州举办了业务培训班,来自上海、重庆、长春、四川等13个分公司的45名档案人员参加了培训。学习班讲解了兵器档案各门类标准,开展了研讨,并进行了案卷整理操作及示范指导。档案人员接受了系统  相似文献   

7.
牛俊强  李嵘  王辛  郭昆 《中国水运》2014,(7):256-257
文中在分析总结了汤堰畈地热田热储展布、地热流体分布特征的基础上,介绍了深部勘查的工作思路、方法、工作布置及实施情况,分析了深部勘查取得的主要成果:地热田范围扩大了1.1倍、地热资源量提高1.3倍、地热流体可开采量提高了0.5倍,勘查深度由350m增加至800m,初步查明了深部热储特征等,在此基础上探讨了深部勘查实施的意义。  相似文献   

8.
黄勇亮 《机电设备》2007,24(10):8-10
针对目前锅炉监控技术问题,提出了采用嵌入式微处理器为控制器核的锅炉状态参数监控设计方案,进行了监控系统的硬件和软件系统的设计,实现了对水位、烟气氧量、蒸汽流量、蒸汽压力、鼓风风量、炉膛温度等现场物理量的采集和处理,提高了锅炉的安全性、经济性和锅炉的寿命.  相似文献   

9.
基于支持向量机的模式识别方法研究   总被引:2,自引:0,他引:2  
本文对支持向量机的原理和应用进行了综合论述。首先,概要叙述了支持向量机(SVM)的产生背景和发展前景。简要介绍了SVM的定义、分类及算法。最后,对SVM在文本识别、数字识别、人脸检测、人脸识别、人脸认证、回归分析及预测、图像检索、特征提取等方面的应用进行了讨论。  相似文献   

10.
本文研究了色氨酸分光光度法测定丙烯醛的性能。对方法的检出限及加标回收率、样品的贮存时间与回收率的关系等做了详细考察,并对混合气体中的丙烯醛进行了测定,考察了甲醛、乙醇、丁酮、正丙醇、苯、甲苯、二甲苯等有机物对该方法的检测影响。  相似文献   

11.
自升式抛石整平平台船的设计与应用   总被引:2,自引:2,他引:0  
王翔  刘榕  罗农 《水运工程》2005,(11):9-13
针对长江口深水航道治理工程恶劣的作业环境,将海上施工平台的概念引用到水下抛石整平施工工艺中,研究的主要内容包括设备的施工作业方式、平台的结构、平台自浮的拖航稳定性、平台支腿靴板对基础的压力、平台升降装置、抛石整平机构及作业时的稳定性等,阐述了平台船的特点和先进性,以及在今后大型水工工程中的应用前景。  相似文献   

12.
多因素数学模型在温州瓯江口浅滩围涂工程研究中的应用   总被引:1,自引:0,他引:1  
建立了波浪、潮流、盐度、悬沙、底床冲淤等多种因素数学模型,在模型验证的基础上,对瓯江口温州浅滩围涂工程海区的波浪场、潮流场、盐度场、悬沙场、底床冲淤场进行了数值模拟研究,对温州浅滩围涂工程对瓯江泄洪、瓯江南北口分流比、乐清湾养殖业、瓯江口港口航道及状元岙深水区、南口口外滩地的影响进行了分析论证。分析研究结果表明,温州浅滩围涂工程是可行的。  相似文献   

13.
We present the observations from a pair of field experiments at the New England shelfbreak front in June and August of 2002, each consisting of 14 cross-frontal surveys using the Lamont Pumping SeaSoar. Measurements of the front's physical, chemical, and bio-optical characteristics were made at high spatial and temporal resolution. The front, based on water-column hydrographic distributions, was found within a few km of the 200 m isobath during both cruises. We present here composite sections, based on averages of individual sections shifted in space to a common frontal location, of the cross-frontal distributions of these properties as a measure of the mean state of the front in both June and August. The observations show the familiar temperature, salinity, and density distributions of the summertime front, dominated by surface thermal heating. Nutrient and bio-optical distributions show the combined effects of water-mass exchange and biological processes. T, S, silicate, and phosphate distributions are suggestive of cross-frontal exchange of slope- and shelf waters, although transport mechanisms and pathways are not apparent. These properties, along with nitrate and optical measures of the suspended particle distributions, show vertical displacements of isopleths as the front is approached: property contours slope upwards toward the front from the shoreward side, and downwards toward the front from the seaward side. Again, actual water-movement pathways are not constrained by these suggestive patterns. Bio-optical distributions show elevated indicators of photosynthetic efficiency both seaward and shoreward of the front, but the front itself is a minimum in biomass. Accumulation of photosynthetic biomass appears to be controlled primarily by nitrate scarcity in waters within and above the pycnocline. At the base of the pycnocline, light limitation appears to be the controlling factor, although the base of the euphotic zone is deeper than the biomass maxima and the base of the pycnocline. Mechanisms explaining this phenomenon are unclear, but tenuous evidence suggests low stratification at the depth of the 1% light level may not allow phytoplankton to optimize for the low-light, high-nutrient conditions at depth. Cross-frontal differences in nutrient and bio-optical parameters, particularly in August, suggest distinct phytoplankton assemblages, and the presence of calcite-forming or nitrogen fixing groups to the community structure, especially in very shallow waters across the front and in pycnocline waters seaward of the front.  相似文献   

14.
The effects of variability in environmental conditions on species composition in benthic ecosystems are well established, but relatively little is known about how environmental variability relates to ecosystem functioning. Benthic invertebrate assemblages are heavily involved in the maintenance of ecological processes and investigation of the biological characteristics (traits) expressed in these assemblages can provide information about some aspects of functioning. The aim of this study was to establish and explore relationships between environmental variability and biological traits expressed in megafauna assemblages in two UK regions. Patterns of trait composition were matched to environmental conditions and subsets of variables best describing these patterns determined. The nature of the relationships were subsequently examined at two separate scales, both between and within the regions studied. Over the whole area, some traits related to size, longevity, reproduction, mobility, flexibility, feeding method, sociability and living habit were negatively correlated with salinity, sea surface temperature, annual temperature range and the level of fishing effort, and positively associated with fish taxon richness and shell content of the substratum. Between the two regions, reductions in temperature range and shell content were associated with infrequent relative occurrences of short-lived, moderately mobile, flexible, solitary, opportunistic, permanent-burrow dwelling fauna and those exhibiting reproductive strategies based on benthic development. Relationships between some traits and environmental conditions diverged within the two regions, with increases in fishing effort and shell content of the substratum being associated with low frequencies of occurrence of moderately mobile and moderately to highly flexible fauna within one region, but high frequencies in the other. These changes in trait composition have implications for ecosystem processes, with, for example, reductions in permanent-burrow dwellers within one of the regions potentially compromising the ability of the assemblages to process and store chemicals and waste products. However, the connections between environmental conditions and trait composition are complex and incorporate many factors. Experimental investigations will be necessary to determine the extent and consequences of these important relationships.  相似文献   

15.
16.
Associated with the rapid increase in the production of cultured marine shrimp has been large‐scale conversion of mangroves to shrimp ponds. Production in many regions has proved to be unsustainable, largely due to inappropriate construction methods, poor environmental conditions, overstocking, and disease. A number of shrimp ponds consequently are unproductive and lie idle. Accurate assessments of pond disuse are difficult to obtain; however, unofficial estimates have suggested that as many as 70% of ponds may be disused after a period in production. Pond construction, shrimp culture, and pond disuse lead to alterations to the physical and chemical properties of soil, hydrological conditions, and the flora and fauna composition of the pond area. The case for restoration, or rehabilitation to a sustainable use, is strong. Consideration must be given to the causes of production failure, the environmental conditions remaining following disuse, the needs and preferences of pond owners and coastal managers, and technical constraints.  相似文献   

17.
When Canadian salmon farmers find the health of their stock is compromised by infection or disease, the use of drugs or pesticides can be required. In Canada, there is a very limited range of these chemicals legally available to farmers and veterinarians. The formal approval and registration process for these chemotherapeutants is complicated. It involves the overlap of a variety of government departments, depending on the method of application of the therapeutic compound. These formal channels, through which chemotherapeutic products, specifically drugs and pesticides, are licensed for use, are both lengthy and costly to navigate. Often, these costs exceed any potential returns from the sale of the products (OCAD, 2001; Harper, 2002). Consequently, unapproved drugs, which would not normally be available for use, are obtained through alternative channels, which may pose a number of environmental, human, and animal safety concerns. This article seeks to provide a better understanding of the approval process and regulations governing drugs and pesticides and how they are made available for use in Canadian salmon culture.  相似文献   

18.
杨宝龙  华斌 《船电技术》2010,30(1):51-53
文章介绍了以NXP的ARM7 TDMI内核控制器为核心的嵌入式通讯平台的设计,包括CAN、工业以太网、USB、RS232、RS485、UART、无线等目前流行的各种通讯方式的设计以及液晶显示、触摸屏、按键的硬件设计,给出了比较完整的方案设计和硬件连接,同时对于所采用的操作系统进行了简单介绍。  相似文献   

19.
船舶防海盗反劫持新措施探讨   总被引:2,自引:0,他引:2  
分析了近期海盗活动的最新情况,介绍了安全舱理念的由来,安全舱的选址,怎样建立紧急撤退程序,如何保障安全舱的安全人,岸基确定船员是否成为人质的方法等,对已发生和预料中的困难提出了建议,对船舶的反劫持措施--建立安全舱,提出了自己的看法.对船舶的防海盗和反劫持工作会有很大的帮助.  相似文献   

20.
A few cities in some of the larger developing countries in Latin America and Asia have made increasing use of multi-year concessions or franchises, competitively awarded to private companies, for construction and operation of urban transport infrastructure and for provision of public transport services. In view of the strong prospective growth of developing-country cities with large transport needs, and the rise in the emerging economies of potential new sources of private capital, it is important to see how effective PPP has so far been in this area. The experience is analyzed principally by thorough comparative review of what has actually happened for some of the main users to date: Bogotá, Santiago, São Paulo, Seoul, and several cities in both China and India. Despite delays and mistakes that have been made in development of most of the projects, the overall results, already delivered and in prospect, are very positive and urban public transport is benefiting substantially, with significant side effects on poorer people's access to work and to services, air pollution levels and road accident rates. The widest and most important advantage of the PPP arrangements, as compared with more conventional short-term contracting, is found to be the innovations, technical and managerial, developed, and, in particular, the mutual capacity building of the countries' private and public sectors and their more effective interaction. The experience in the six countries covered suggests that other developing-country cities may be best assisted to develop sound urban transport PPPs more rapidly through provision of help on chosen items among 7 elements that have proved particularly crucial but sometimes weak in the projects reviewed: Civic consultation systems, Land-use/Transport strategic planning, Land/property market management, Monitoring systems, Progressive policies, Economic regulation, and Public institutional framework for PPPs.  相似文献   

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