共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
光敏电阻是一种典型的光电导器件。所谓光电导效应是表示材料(或器件)受到光辐射后,材料(或器件)的电导率发生变化。光敏电阻和其它半导体光电器件相比有以下特点: 1.光谱响应范围宽。根据光电导材料的不同,光谱响应可从紫外光、可见光、近红外扩展到远红外,尤其对红光和红外辐射有较高的响应度。 2.工作电流大,可达数毫安。 3.所测光强范围宽,既可测强光也可测弱光。 4.灵敏度高,光导电增益大于1, 5.偏置电压低,无极性之分,使用方便。 相似文献
7.
以GaN基功率型蓝光LED加黄色荧光粉合成白光的技术具有生产成本低,器件性能稳定和市场容易接受等优点,是最经济有效的产生自光的技术路线,目前半导体照明几乎全部采用此种技术路线。但是基于传统封装的白光LED器件并不能简单用于照明或代替传统照明光源,原因在于白光LED器件是高亮度、小光通光源。如果在光学上不进行处理,LED的光源会非常眩目,照度均匀性会很差,从而在照明效果上不如传统照明光源,最终导致用户和市场不能接受。 相似文献
8.
9.
有关激光和LED产品的光学安全要求,目前有两个最基本的标准(要求):一个是美国的CDRH的激光安全要求,另一个是IEC的激光产品安全标准IEC60825。尽管两者都对激光产品提出了最基本的安全要求,但它们之间还是存在着细微的差别。CDRH:放射卫生和器械中心(Center for De-vice and Radiological Health),是美国FDA下属的部门。FDA食品和药品管理局(Food and Drug Adminis-tration)隶属于美国国务院保健与服务部(U.S.Department Of Health and Human Services)的公共健康服务署(Public Health Service),负责美国所有有关食品,药品,化妆品及辐射性仪器的管理,它也是美国最早的消费者保护机构。IEC:国际电工委员会(International Electrotechnical Commission) 相似文献
10.
11.
12.
在太阳能光-热-电转换利用的"三环节理论"模型的基础上,对太阳能光-热-电转换利用进行了(火用)经济学分析,并与常规火力发电的(火用)经济学作了对比,提出了化石能源的稀缺(火用)价值和环境成本的观点.探讨了聚焦型太阳能集热器的设计参数对太阳能光-热-电转换利用系统中单位输出(火用)价Cu的影响. 相似文献
13.
14.
在太阳能光-热-电转换利用的"三环节理论"模型的基础上,对太阳能光-热-电转换利用进行了(火用)经济学分析,并与常规火力发电的(火用)经济学作了对比,提出了化石能源的稀缺(火用)价值和环境成本的观点.探讨了聚焦型太阳能集热器的设计参数对太阳能光-热-电转换利用系统中单位输出(火用)价Cu的影响. 相似文献
15.
目前热电厂在进行供热供地耗的计算中,因计算方法不同,使得管理水平、锅炉效率相近的热电厂相差较大,存在一些不尽一致的地方。对此通过实例计算提出一种简便实用的计算方法,该方法有助于热电厂技术经济分析。 相似文献
16.
17.
介绍了微型燃气轮机(微燃机)冷热电三联产系统(三联产)的构成,利用热力学理论对三联产系统在额定工况下的产品成本单价进行了分析,计算了在不同天然气成本单价和微燃机不同工况下排气(烟气)余热利用率ηy的发电量成本单价和制冷量成本单价。计算表明,发电量成本单价随ηy的增加而减小;天然气成本单价增加会增大发电量成本单价;提高ηy对降低发电量成本单价有作用;制冷量成本单价随天然气成本单价增加而增加;ηy在70%后对单位制冷量成本单价的影响降低。 相似文献
18.
T. J. HAMMONS 《电力部件与系统》2013,41(7):693-711
ABSTRACT This paper discusses East and Central European Electricity Infrastructure, Interconnections and Electricity Exchanges following segregation of the republics of former USSR and independence of East European countries, and likely developments in future years. It focuses on the present and future state of the electric power sector, future expansion of European power systems, co-operation, new capacity, separation of power systems in former USSR countries, the direction of reforming the industry, interstate relations in the fuel and energy complex, and impact of privatisation on electricity supply. First, power sector problems in countries in transition are reviewed. Serious deficiencies in electricity supply affect economic reforms, and lack of investment together with poor operational performance plague the power industry, particularly in the republics of former USSR. Important issues of the CENTREL power companies: Czech, Hungarian, Polish and Slovak are discussed, for example, (a) improvement in quality of the power systems, (b) interconnection with the UCPTE system, (c) co-ordination of co-operation with other power systems, and (d) beneficial energy transactions. Development of technical solutions of future operation with eastern neighbours including back-to-back couplers are also discussed. The German Power System following unification requiring synchronous operation of the East-West power networks is commented on together with new interconnecting lines for synchronising the systems late in 1995. Discussed also are technical, economic, financial and legal aspects of exchanging about 4GW between Russia, Belarus, Poland and Germany using a multi-terminal HVDC transmission system and the idea of a Baltic Ring forming a meshed interconnection around the Baltic Sea. Problems of co-operation in former USSR are also reviewed. Highlighted is the fuel and energy complex, rate of new capacity commissioning, use of existing generating capacity, and separation of power systems in a number of republics from the Unified Grid Network. Dynamics of changes in basic indexes such as installed capacity, electric power generation and consumption in countries of the Commonwealth of Independent States’ (CIS), and in electric power an energy exchanger in CIS countries and between Eastern Europe are also discussed. The paper then examines the role of Russian Power Systems in the future Unified Electrical Power System of the Euro-Asian Continent. In the foreseen future, a chain of power systems stretching from Beijing to Madrid with total length exceeding 10,000km will be interconnected, comprising national grids of China, Siberia, Kazakhstan, Russia, Southwest republics of former USSR, East Europe and West Europe. 相似文献
19.
广东某地原规划的燃煤热电联产(燃煤CHP)机组能取得较好的经济效益,但大气污染物排放较高;原规划的天然气热电联产(天然气CHP)机组在相对于燃煤CHP机组较高的上网电价条件下,其经济效益可以与燃煤CHP机组竞争,但由于热电比较小,天然气CHP整体环境效益仍不理想。对此,建议采用天然气冷热电三联产(天然气CCHP)机组,虽然发电量相对较少,但能源利用效率提高,环境效益相对也较好。 相似文献