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1.
介绍了一种在线称重系统中的嵌入式速度控制器,给出了控制器的硬件结构及主要部分的工作原理,并详细介绍了其软件设计思想。通过现场测试,该速度控制器反应灵敏,运行稳定。  相似文献   

2.
本文主要介绍了如何利用变频器的蓄电池功能设计开发电梯停电应急运行装置,并阐述了运行装置的原理和逻辑结构。  相似文献   

3.
《江苏船舶》2000,17(3):23-26
介绍我公司自行设计制造的 30 0t× 112m× 70m大型造船门式起重机的主要特点 ,材料选用、主结构形式、起升机构及大车运行机构的控制方式。概述了有限元法在 30 0t大型门式起重机结构计算中的应用。  相似文献   

4.
空气压缩机作为气动控制系统的气源设备,其在运行过程中的稳定程度和可靠性直接影响到船舶的安全,因此必须对空压机的运行进行全面的监控。文章通过分析ISaGRAF控制软件的体系结构和运行机制,提出了船舶空压机实时监控系统的软PLC实现方法,介绍了该系统的结构、主要功能特点及软件设计等。  相似文献   

5.
倪少玲 《造船技术》1995,(12):38-39,13
本文从软件工程角度,介绍了船模试验数据分析与处理软件系统的特点、各个子系统主要功能、数据库结构、船模试验数据处理及实船性能预报软件,以及系统运行的硬件配置、微机系统的正确设置。  相似文献   

6.
柔性交流输电系统(FACTS)是近年来出现的一项新技术,本文对柔性交流输电技术的概念及发展现状进行了简要介绍,详细论述了 FACTS 中几种主要控制器的结构原理及应用。最后总结了 FACTS 控制器在电力系统潮流控制、系统振荡、稳定性运行中的重要作用以及FACTS的发展前景。  相似文献   

7.
通过对国外进口设备及项目自身特性和组成的分析研究,结合模块化的设计思想,研制出大吨位船舶制造专用液压安装平台。通过力学计算及结构变形分析,为系统设计提供参考。同步控制策略保证系统运行稳定性。本文主要介绍了系统构成及控制策略实现。  相似文献   

8.
《港口工程总平面CAD》新版软件的开发研制   总被引:1,自引:0,他引:1  
文章介绍《港口工程总平面CAD》新版软件的功能,主要技术特点,系统总体结构,运行环境及技术路线。  相似文献   

9.
介绍了某油漆厂油漆加工过程计算机控制系统的组成、基本方案、控制软件的结构和主要功能模块设计,VC++6.0多线程技术在智能仪表通信中的解决方法以及温度控制仪表网络通讯的实施过程.实现了网络数据通讯、集散控制以及数据管理.应用表明,系统运行稳定可靠,提高了油漆加工技术的自动化及产品质量.  相似文献   

10.
张仑 《中国水运》2007,5(10):210-212
文章主要阐述了电动机的机械特性,电动机软起动的含义,用可编程序控制器控制电动机软起动的硬件结构和工作原理,介绍了电动机软起动的可编程序控制器的程序设计思想,程序调试,故障处理和主要保护功能.并且介绍了到用户现场调试和运行情况.  相似文献   

11.
The world’s oceans and coasts are awash in a sea of politics. The marine environment is increasingly busy, changing, and a site of degradation, marginalization, injustice, contestation and conflict over declining resources and occupied spaces at local to global scales. Themes of political ecology, such as power and politics, narratives and knowledge, scale and history, environmental justice and equity, are thus salient issues to understand in ocean and coastal governance and management. This subject review examines research on these themes of political ecology in the ocean and coastal environment and reflects on how the insights gained might be applied to governance and management. Political ecology provides important insights into: the influence of power in ocean management and governance processes; the manner in which narratives, knowledge, and scale are used to legitimize and shape policies and management efforts; the effects of historical trajectories on present circumstances, options, and practices; and the nature of inequities and environmental injustices that can occur in the marine environment. Moreover, ocean and coastal researchers, practitioners, and decision makers ought to engage with the political processes and injustices occurring in the ocean. Moving from critical insights to constructive engagements will ensure that political ecology helps to plant seeds of hope in the Anthropocene ocean.  相似文献   

12.
张晓怀  陈业初  寇蔚 《机电设备》2007,24(11):29-33,13
诊断软件由于其诊断对象的复杂性和诊断策略的多样性,为设计模式的使用提供了较大空间.将设计模式引入船用机电设备故障红外智能诊断软件的开发,并具体讨论了一些常见的模式如Adapter、Bridge、Strategy和Observer等在软件各个模块和环节中的应用.实验证明,设计模式的使用,简化、明晰了软件的结构,加强了软件的通用性、稳定性和灵活性,提高了软件的可理解性和可维护性,并使得丰富红外诊断软件的接口和功能变得更为容易,进一步拓宽了软件的使用范围.  相似文献   

13.
中国修船业在国家改革开放的浪潮中,经历了三十多年的快速发展,如今已稳居世界修船大国的国际地位,而中国修船企业正在引领世界绿色修船科技的进步,也引起了国际修船业的高度关注.然而,在人类社会生态环境面临严峻挑战的当下,作为世界贸易和港口经济重要组成部分的修船产业,如何形成发展新格局,从生态层面推进绿色、低碳、数字"一体化"...  相似文献   

14.
基于200米级高扬程升船机固定壁厚塔柱结构形式,以混凝土用量一致为原则,拟定变壁厚塔柱结构形式。采用有限元软件ABAQUS,分别建立了固定壁厚和变壁厚两种塔柱结构模型,对塔柱结构的动力响应进行对比分析。结果表明:1)在自重荷载、风荷载和8度地震作用下,固定壁厚塔柱结构和变壁厚塔柱结构的顶部最大位移分别为38. 5、34. 7 cm,均满足规范限值。2) 3条地震波作用下,两种塔柱结构的顶部加速度比底部加速度都大,呈现加速度放大效应,放大2倍左右。3)筏形基础与塔柱结构交界面出现了压应力集中,筏形基础左右、中间部分及筒体内部区域出现了拉应力集中。塔柱截面和挡土墙交界处易发生应力集中。4)变壁厚塔柱结构的顶部最大位移,筏形基础的最大拉、压应力,截面最大等效应力,均比固定壁厚要小较多。变壁厚塔柱结构形式更优。  相似文献   

15.
张少华  刘慧敏 《世界海运》2002,25(6):41-42,49
阐述了最新研制开发的船舶自动化电站模拟器主要组成及功能原理。其基本功能是:操作控制的模拟功能,机组的安全保护功能,电站、拖动系统仿真功能,教学考评功能,与整个轮机模拟器联网的扩展功能。电站监控系统具有配电屏面监视、机舱监控、电力系统实时监视及控制4部分功能,并有运行参数动态监视,报警的记录及打印功能。  相似文献   

16.
Road transport imposes negative externalities on society. These externalities include environmental and road damage, accidents, congestion, and oil dependence. The cost of these externalities to society is in general not reflected in the current market prices in the road transport sector.An efficient mobility model for the future must take into account the true costs of transport and its regulatory framework will need to create incentives for people to make sustainable transport choices. This paper discusses the use of economic instruments to correct road transport externalities, but gives relatively more weight to the problem of carbon emissions from road transport, as this is particularly challenging, given its global and long-term nature.Economics offers two types of instruments for addressing the problem of transport externalities: command-and-control and incentive-based policies.Command-and-control policies are government regulations which force consumers and producers to change their behaviour. They are the most widely used policy instruments. Examples include vehicle emission and fuel standards in the US as well as driving or parking restrictions in Singapore. The implementation cost of these instruments to the government is small. Although from an economic perspective these policies often fail to achieve an efficient market outcome, the presence of political constraints often make them the preferred option, in terms of feasibility and effectiveness.Economic theory shows how policies, which affect consumption and production incentives, can be used to achieve the optimal outcome in the presence of externalities. Incentive-based policies function within a new or an altered market. We first examine incentive-based policies, which cap the aggregate amount of the externality, such as carbon emissions, by allocating permits or rights to the emitters. The emitters are then free to trade their permits amongst them. The permit allocation mechanism is important-although market efficiency would be satisfied by an auction, political influences usually favour a proportional allocation based on historic emissions. We discuss EU ETS as an example of a cap-and-trade system, however, no such policy for CO2 emissions in road transport has been implemented anywhere in the world to date.Fiscal instruments are, like command-and-control, widely used in road transport, because they are relatively cheap and simple to implement. They include the use of taxes and charges in order to bridge the gap between private and the social costs and, in principle, can lead to an efficient market solution. Registration, ownership, fuel, emissions, usage taxes, and parking and congestion charges have been implemented in many countries around the world. On the other side of the spectrum, subsidies can be given to those scrapping old cars and buying fuel-efficient vehicles. Some cities, such as London, have implemented congestion charges and many states in the United States have introduced high occupancy lanes. Other interesting possibilities include pay-as-you-drive insurance and other usage charges. However, the size and scope of taxes and subsidies are determined by governments, and because of their imperfect knowledge of the market the outcome is still likely to be inefficient.Governments have many effective economic instruments to create a sustainable road transport model. These instruments can be used separately or together, but their implementation will be necessary in the nearest future.  相似文献   

17.
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   

18.
双鱼岛作为离岸式城市综合开发类人工岛,岛上陆域高程是一个独立的系统,陆域高程的确定关系到规划、安全、护岸、景观、土方量和造价、防洪排涝、亲水性等。对人工岛填海造地期和使用期高程确定的主要因素进行论述,并整体介绍双鱼岛高程的变化趋势,对不同部位的高程确定进行分析,同时对工程安全性与景观的平衡、高程与上部规划的关系、高程与土方量及最优造价进行研究。研究成果可供类似工程的高程确定提供思路及参考。  相似文献   

19.
金锋 《水运工程》2021,(2):89-92
针对升船机运行可靠性问题,以齿轮齿条爬升式升船机驱动系统为研究对象,根据可靠性理论,在统计驱动系统运行维护数据的基础上,综合分析停机故障次数和故障检修停航时间对运行可靠性的影响,计算得出驱动系统及其部件的运行可靠度,提出提高驱动系统运行可靠性的建议:应高度重视驱动齿轮托架机构、电气传动设备、传感检测装置等机电设备的维护检修和优化完善,充分考虑设备检修的便利性;基于停机故障次数和故障检修停航时间的运行可靠度计算分析方法,能准确反映升船机的运行可靠性。  相似文献   

20.
At the time of writing (2010), the world is witnessing the aftermath of the most severe financial sector meltdown in modern economic history caused by the real estate bubble in the United States. Its consequences on the real economy, especially in Europe, are yet to be fathomed, and this of course includes the longer-term impacts on international ocean transportation, ports and the distribution of global production.The economic recession has left the international shipping and port sectors with substantial overcapacity. This has resulted in drastic cost cutting measures on the one hand, and voluntary, often consensual, and coordinated reduction of supply on the other. These measures, together with a noticeable recovery in demand, are gradually leading again to improvement in prices charged by carriers and other transport service providers.In view of the country’s expanse; size of population; and regional inequalities, India’s dry ports (inland cargo consolidation and distribution centres) are seen by the government as a pivot of export-led growth and economic development (Haralambides & Gujar, 2011). Moreover, public and private sectors alike see the coordinated development of dry ports as the only way forward in terms of easing pressures at congested coastal ports, thus improving supply chain efficiency. In spite of this, dry port development and operations are still dominated by the public sector, under prices, capacity, land acquisition policies and other conditions that make private sector participation risky and comparatively unattractive. In order to rationalize dry port capacity and prices, this paper argues in favour of greater devolution through competition-enhancing Public-Private Partnerships (PPPs). The paper puts forward recommendations for the necessary legal, regulatory and general economic policy interventions based on international best practice, while keeping Indian specificities in the right perspective.  相似文献   

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