共查询到18条相似文献，搜索用时 187 毫秒
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国民经济的发展,带动了能源需求量的日益增加,能源供应日显紧张。太阳能作为可再生能源的一种,取之不尽,用之不竭,同时又不会增加环境负荷,必将成为未来能源结构中的重要组成部分。我国建筑能耗中,生活热水、供暖耗能占了相当的比例,利用太阳能来满足生活热水、供暖等能耗需求具有巨大节能效益。内蒙古中西部地区具有太阳能利用的良好条件,太阳能热水已逐渐普及城乡,太阳能采暖技术却面临着设计的瓶颈。 相似文献
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做好建筑节能工作,是落实科学发展观,建设节约型社会和节约型城镇的重要举措,也是现代建筑技术发展的方向。把太阳能开发利用作为一个重点,利用太阳能解决冬季采暖和四季生活热水供应,以减少建筑能耗,发展城乡节能建筑体系,是西藏建筑节能设计标准的一个重要宗旨。希望能给在建筑领域里工作的同志们一点启示。 相似文献
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北方城市冬季采暖主要热源是燃煤锅炉,众所周知,大量燃煤造成严重的大气污染、破坏生态环境、影响人的健康。人们已经寻找到新的比较清洁的燃料替代煤炭,比如天然气、石油、核能、电力等。这些燃料用于采暖,成本很高,分别是燃煤的３～５倍。太阳能和地热不用燃烧,在自然界里存量大,可直接加以利用,既清洁又廉价,大有发展前途。只是目前尚存在采集和储存等技术成本问题,影响这两种热源的大规模利用。地热几乎是取之不尽的可再生资源,但地下热水埋深较大,受补给较慢的制约,开采量十分有限。一般讲,水温较高的地热水可以直接用于… 相似文献
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地板采暖技术是一项实现环保与节能的重大措施 总被引：1，自引：0，他引：1
低温热水地板辐射采暖技术是把一种塑料管埋人混凝土地板中,管中通有不高于60℃的循环热水,热水把热量释放到混凝土地板中,均匀地辐射到室内,以达到采暖的目的。它除了具有卫生条件好,安全舒适,不占用室内面积等优点外,更重要的是它比 相似文献
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《Chemie der Erde / Geochemistry》2016,76(4):463-480
Since about half a century samples from the lunar and asteroidal regoliths been used to derive information about elemental and isotopic composition and other properties of the present and past solar wind, predominantly for the noble gases and nitrogen. Secular changes of several important compositional parameters in the solar wind were proposed, as was a likely secular decrease of the solar wind flux. In 2004 NASA’s Genesis mission returned samples which had been exposed to the solar wind for almost 2.5 years. Their analyses resulted in an unprecendented accuracy for the isotopic and elemental composition of several elements in the solar wind, including noble gases, O and N. The Genesis data therefore also allow to re-evaluate the lunar and meteorite data, which is done here. In particular, claims for long-term changes of solar wind composition are reviewed.Outermost grain layers from relatively recently irradiated lunar regolith samples conserve the true isotopic ratios of implanted solar wind species. This conclusion had been made before Genesis based on the agreement of He and Ne isotopic data measured in the aluminum foils exposed to the solar wind on the Moon during the Apollo missions with data obtained in the first gas release fractions of stepwise in-vacuo etch experiments. Genesis data allowed to strengthen this conclusion and to extend it to all five noble gases. Minor variations in the isotopic compositions of implanted solar noble gases between relatively recently irradiated samples (<100 Ma) and samples irradiated billions of years ago are very likely the result of isotopic fractionation processes that happened after trapping of the gases rather than indicative of true secular changes in the solar wind composition. This is particularly important for the 3He/4He ratio, whose constancy over billions of years indicates that hardly any 3He produced as transient product of the pp-chains has been mixed from the solar interior into its outer convective zone. The He isotopic composition measured in the present-day solar wind therefore is identical to the (D + 3He)/4He ratio at the start of the suns’s main sequence phase and hence can be used to determine the protosolar D/H ratio.Genesis settled the long-standing controversy on the isotopic composition of nitrogen in lunar regolith samples. The 15N/14N ratio in the solar wind as measured by Genesis is lower than in any lunar sample. This proves that nitrogen in regolith samples is dominated by non-solar sources. A postulated secular increase of 15N/14N by some 30% over the past few Ga is not tenable any longer. Genesis also provided accurate data on the isotopic composition of oxygen in the solar wind, invaluable for cosmochemisty. These data superseded but essentially confirmed one value – and disproved a second one – derived from lunar regolith samples shortly prior to Genesis.Genesis also confirmed prior conclusions that lunar regolith samples essentially conserve the true elemental ratios of the heavy noble gases in the solar wind (Ar/Kr, Kr/Xe). Several secular changes of elemental abundances of noble gases in the solar wind had been proposed based on lunar and meteoritic data. I argue here that lunar data – in concert with Genesis – provide convincing evidence only for a long-term decrease of the Kr/Xe ratio by almost a factor of two over the past several Ga. It appears that the enhancement of abundances of elements with a low first ionisation potential in the solar wind (FIP effect) changed with time.Finally, Genesis allows a somewhat improved comparison of the present-day flux of solar wind Kr and Xe with the total amount of heavy solar wind noble gases in the lunar regolith. It remains unclear whether the past solar wind flux has been several times higher on average than it is today. 相似文献
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夏季青藏高原加热和环流场的日变化 总被引：3，自引：0，他引：3
通过使用NCEP/NCAR再分析资料,分析了夏季青藏高原地区非绝热加热场的日变化特征以及高原上空环流场的日变化特点。分析发现青藏高原及其邻近地区上空环流的日变化在欧亚地区大气环流系统中表现最为显著。环流日变化是被非绝热加热的日变化所驱动的,特别是被太阳辐射日变化所驱动。由于高原上空大气柱质量远小于低海拔的平原地区,故太阳辐射日变化引起的加热日变化可在高原地区产生更为显著的环流日变化。通过位涡方程的诊断证实,白天高原加热增强,可在大气上层制造大量负位涡并向周边地区辐散,使高原地区大气高层成为负涡源。而低层则是加热制造正位涡,并使周边地区向高原的辐合增强,摩擦耗散是低层抑制正位涡增长的主要因素。而夜间加热减弱使高原对局地环流的影响作用大为减弱。故而高原及其周边地区的局地环流也具有明显的日变化特征。 相似文献
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陨石是来自含气体-尘粒的太阳早期星云盘凝聚和吸积的原始物质,大多数原始物质因吸积后的作用过程而改变（如月球、地球及火星样品）,但有一些却完整的保存下来（如球粒陨石或球粒陨石中的难熔包体）。这些原始的物质通常依据同位素丰度特征来识别,依据其矿物-岩石学特征和成因可将已知的陨石划分许多更小的类型。陨石学及天体化学的新近进展包括：新近识别的陨石群;发现新类型球粒陨石及行星际尘粒中发现前太阳和星云组分;利用短寿命放射性核素完善了早期太阳系年代学;洞察宇宙化学丰度、分馏作用及星云源区及通过次生母体的作用过程阐释星云和前星云的记录。本文概述了早期太阳系内从星云到陨石的演化过程。依据这些资料,对早期太阳系所经历的多种核合成的输入、瞬时加热事件与星云动力学有一些新的认识,以及认识到小星子和行星体系的演化比以前预期的更快速。 相似文献
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N. Santillán Soto O.R. García Cueto S. Ojeda Benítez N. Velázquez Limón M. Quintero Núñez M. Schorr 《Atmósfera》2013,26(4):499-507
Solar radiation is one of the most important energy resources of our planet. The interest in its use as a renewable and clean energy to mitigate the greenhouse gases (GHG) effects has increased significantly. This paper evaluates the measurements of global solar radiation and its energy potential and presents a comparison between both of them, as an example of the effort to reduce GHG emissions. The measurements were made with pyranometers installed in the city of Mexicali, Baja California, located in northwestern Mexico, and the city of Yuma, Arizona, located in the southwestern United States. Separated by a distance of 96 km, both cities have a sustained development and are climatically similar, since they present numerous sunny days, extreme hot temperatures and little precipitation. The results presented show differences in their behavior and in the solar radiation measurement values, especially for the critical spring and summer seasons, with values 15.73% (0.042 kW/m2) higher in Mexicali with respect to Yuma. Energy power is estimated, and it is discussed with some variables as global solar radiation, rainfall, air temperature, relative humidity and climatology of clear, partly cloudy, and cloudy days. With this estimation, the solar energy used and GHG avoided is projected for Mexicali. It is assessed that 291 tons of GHG are prevented. The Mexicali values of potential energy are higher than those of Yuma; therefore, this solar and energy comparative study provides reasons to develop these technologies in Mexico, but solar technologies should be deployed also in Yuma. The measured data at the regional level demonstrate their importance, and the relevance of the proposed mitigation strategy for climate change. 相似文献
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近几十年来,全球和我国大部分区域的地面太阳辐射都经历了一个从减少到增加的过程,也就是所谓的地球“变暗”到“变亮”;引起这种变化的原因复杂多样,总云量的变化无法完全解释,而气溶胶的变化则有可能在某些地区（包括中国）起着重要作用;地面太阳辐射的这种变化会产生重要的气候效应,在“变亮”的过程中有可能使温室气体的增暖效应表现得更加明显。从以上3个方面,对近几年国内外利用地面观测资料和卫星遥感资料所得到的最新研究成果进行了总结和分析,这些研究所揭示的与全球气候变化有关的基本事实也可以为我国的气候变化研究提供一定的参考和启示。 相似文献
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太阳系形成及演化研究方法 总被引：3，自引：0，他引：3
通过对陨石的研究,说明太阳系的形成与演化历史,包括太阳星云的凝聚过程、高温加热熔融事件和低温蚀变过程,陨石母体的热变质作用、熔融分异作用以及冲击变质作用等。对太阳星云的化学组成和同位素组成不均一性、前太阳物质的存在及其意义、太阳系形成和演化的同位素绝对年龄、间隔年龄以及宇宙射线暴露年龄等进行了讨论。结合太阳系形成和演化的研究,特别对电子探针、离子探针、透射电子显微镜以及拉曼光谱等微束分析技术在该领域的应用和相关问题进行了讨论。 相似文献
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太阳风中磁流体湍流的特征和本质 总被引：1，自引：0，他引：1
在空间探测的早期,太阳风湍流现象就已经被空间飞船的观测发现了。但是太阳风湍流不同于过去学术界熟悉的流体湍流。虽然国际学术界已进行了长期的研究,但太阳风湍流的本质仍不能得到明确的认识,许多观测现象都得不到解释。涂传诒等［1～5］研究了这些现象,促进了理论上的新进展。这些研究指出,太阳风起伏中存在着非线性湍流相互作用,但不是完全发展的湍流,而是正处于由阿尔芬波向着完全发展的湍流过渡的状态。这一新的概念把阿尔芬波传播理论与磁流体湍流理论结合起来,导致了理论上的新进展,从而揭示了太阳风湍流的本质,阐明了一系列过去不能解释的观测现象。着重介绍了这些研究的成果和意义。 相似文献
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我国油页岩地质资源量巨大,是保证我国能源安全的重要战略资源。油页岩地下原位转化开采是油页岩工业的发展趋势,在系统收集相关资料、数据和调研的基础上,总结了国内外油页岩原位转化技术的发展历程,提出了高效加热技术、储层改造技术和地下空间封闭技术三个油页岩原位转化核心技术,并对这三大核心技术的主要技术特点和发展现状做出了进一步分析。在明确油页岩地下原位转化开采低成本、高产量和低污染的目标基础上,提出了地表井下协同加热-多阶段物理化学复合加热-自生热驱动链式原位裂解的热流体原位复合加热技术、双水平井小井距电磁测距导向技术、多工艺精确储层改造压裂技术、注浆帷幕和气驱止水地下空间封闭技术等油页岩原位转化核心技术的发展方向,以期对我国油页岩地下原位转化开采技术提供借鉴和参考。 相似文献