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901.
中短波广播发射台电磁辐射环境影响预测模型   总被引:4,自引:0,他引:4       下载免费PDF全文
为预测中短波广播发射台的电磁辐射环境影响,根据国家相关电磁辐射标准,研究和分析了中短波广播发射台电磁辐射环境影响理论预测模型,编辑了中短波发射台电磁辐射环境影响计算分析程序,验证发现实际监测符合理论预测.实例计算了中短波发射台周围的电磁辐射影响,表明程序的计算结果可用于指导中短波发射台周围的建设.  相似文献   
902.
基于长江中游5个气象辐射站点1961年以来的每日太阳辐射成分及其他气象观测数据,应用线性回归、相关分析、Pettitt突变检验等方法,探讨了近半世纪以来长江中游城市群太阳辐射的变化特征,指明地面接收太阳辐射的突变年份,并分析了太阳辐射与相关气象要素的关系。结果表明:近53年来长江中游地面接收太阳总辐射呈现先下降("变暗")、后上升("变亮")的趋势,该区域的辐射变化与全球范围内的"变暗"及"变亮"的变化趋势是一致的。日照时数与太阳辐射呈现较为显著的正相关性,相关系数r为0.63;而降水量则与太阳辐射呈现负相关性,相关系数r为–0.41。太阳辐射的这种突变变化也直接导致了气温的变化,在"变暗"阶段,太阳辐射与最高气温、气温日较差呈现出显著的正相关性,相关系数分别达到0.61和0.82,但其与最低气温、平均气温的相关性则不显著;在"变亮"阶段,太阳辐射与最高气温、气温日较差、平均气温呈现出正相关性,相关系数分别为0.56、0.62以及0.46,但其与最低气温的相关性则不显著。  相似文献   
903.
The generation of power from the reduction of fossil fuels is the biggest challenge for the next half century. The idea of converting solar energy into electrical energy using photovoltaic panels holds its place in the front row compared to other renewable sources. But the continuous change in the relative angle of the sun with reference to the earth reduces the watts delivered by solar panel. In this context solar tracking system is the best alternative to increase the efficiency of the photovoltaic panel. Solar trackers move the payload towards the sun throughout the day. In this paper different types of tracking systems are reviewed and their pros and cons are discussed in detail. The results presented in this review confirm that the azimuth and altitude dual axis tracking system is more efficient compared to other tracking systems. However in cost and flexibility point of view single axis tracking system is more feasible than dual axis tracking system.  相似文献   
904.
The development of renewable energy is one manifestation of current transformations in the organisation of European energy production and markets. To illuminate the changes triggered by renewable energy policy, the evolution of solar photovoltaic policy in France is analysed with a focus on its central instrument, feed-in tariffs (FITs). FITs for photovoltaics raised difficulties in many countries, but their effects were particularly dramatic in France. Market sociology and science and technology studies are employed to describe FITs as agencements organising the markets and politics of electricity production. FITs are considered as inherently unpredictable insofar as they encourage innovation and the emergence of new actors. The ways in which three successive agencements of FITs for photovoltaics framed the politics and economy of photovoltaics in France, and how they addressed unanticipated effects, are discussed. This is suggestive of transformations and tensions in the construction of French energy policy.  相似文献   
905.
Persistent organic pollutants (POP) in human milk originating from various sources are used as environmental exposure markers. Further, mothersmilk is a predominant pathway for human exposure for suckling infants to POP. The aim of present study was to provide baseline and time trend information on human milk POP concentrations in the Republic of Moldova. A pooled sample of breast milk was analyzed in 2009 and 2015 and health risk evaluated by comparing reference values of humans' daily intake with estimated daily intake (EDI). Results showed decreases for concentrations of dichlorodiphenyltrichloroethane, hexachlorobenzene, dieldrin, heptachlor, α and β-hexachlorocyclohexane, polychlorinated biphenyls, dioxin-like polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans between sampling periods. Regardless of the decrease, EDI was higher than reference values for dioxins toxic equivalents, polychlorinated biphenyls and β-hexachlorocyclohexane in both phases. However, increased levels were detected for polybrominated diphenyl ethers (twofold) and hexabromocyclododecane (threefold) from 2009 to 2015, but the EDI in both phases is much lower than the reference. The decline in certain POP levels may be attributed to coordinated efforts undertaken by national and international entities to regulate these compounds. The basis for the elevated levels of polybrominated diphenyl ethers and hexabromocyclododecane remains unknown but raises concerns regarding lactational exposure.  相似文献   
906.
While energy-sector emissions remain the biggest source of climate change, many least-developed countries still invest in fossil-fuel development paths. These countries generally have high levels of fossil-fuel technology lock-in and low capacities to change, making the shift to sustainable energy difficult. Tanzania, a telling example, is projected to triple fossil-fuel power production in the next decade. This article assesses the potential to use internationally supported Nationally Appropriate Mitigation Actions (NAMAs) to develop solar energy in Tanzania and contribute to transformational change of the electricity supply system. By assessing the cultural legitimacy of NAMAs among key stakeholders in the solar energy sector, we analyse the conditions for successful uptake of the concept in (1) national political thought and institutional frameworks and (2) the solar energy niche. Interview data are analysed from a multi-level perspective on transition, focusing on its cultural dimension. Several framings undermining legitimacy are articulated, such as attaching low-actor credibility to responsible agencies and the concept’s poor fit with political priorities. Actors that discern opportunities for NAMAs could, however, draw on a framing of high commensurability between experienced social needs and opportunities to use NAMAs to address them through climate-compatible development. This legitimises NAMAs and could challenge opposing framings.  相似文献   
907.
In this study, the optimal sizing and performance analysis of a standalone integrated solar power system equipped with different storage scenarios to supply the power demand of a household is presented. One of the main purposes when applying solar energy resource is to face the increasing environmental pollutions resulting from fossil fuel based electricity sector. To this end, and to compare and examine two energy storage technologies (battery and hydrogen storage technology), three storage scenarios including battery only, hydrogen storage technology only and hybrid storage options are evaluated. An optimization framework based on Energy Hub concept is used to determine the optimum sizes of equipment for the lowest net present cost (NPC) while maintaining the system reliability. It was determined that the most cost effective and reliable case is the system with hybrid storage technology. Also, the effects of solar radiation intensity, the abatement potential of CO2 emissions and converting excess power to hydrogen on the system’s performance and economics, were investigated and a few noticeable findings were obtained.  相似文献   
908.
核能与核技术利用事业的快速发展为我国经济社会发展提供了强大的助推力,但也使得我国面临的核与辐射安全风险日益加大,对核与辐射安全监管的需求与日俱增。当前,我国核与辐射安全监管工作挑战与机遇并存。介绍了我国核与辐射安全监管工作开展现状,分析了其中存在的困难与问题,提出亟需利用信息化及大数据技术,推动我国核与辐射安全监管现代化进程。基于我国核与辐射安全监管数据现状,提出了促进我国核与辐射安全监管数据管理水平提升的几点措施,包括完善数据管理体制,提升数据管理技术,转变数据管理思维,树立数据共享意识等。此外,详细阐述了核与辐射安全监管大数据建设策略,包括总体架构、建设目标、主要任务等。  相似文献   
909.
介绍了某社保(终端/便民/访客)服务器终端在电子产品电磁兼容认证中经常遇见的辐射骚扰和传导骚扰测试项目,重点从PCB板级电路EMC设计方面进行测试不合格原因分析,并给出整改对策。并由此案例引出电子产品电磁兼容设计时的注意事项,以图能给电子产品设计工程师提供参考,使其能以较高概率一次性通过EMC认证。  相似文献   
910.
首先通过理论分析了线缆在电场中产生的电流大小,其次使用带状线装置产生均匀场强,通过测量找出线缆感应电流与场强之间的传输函数关系,从而验证了BCI法与空间辐射场的等效性,这为将来我国汽车电子BCI法制定合适的试验限值提供了参考。  相似文献   
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