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401.
日光温室中加扣小拱棚的温湿度效应 总被引:1,自引:0,他引:1
利用2013年1-2月河北省清河县日光温室中加扣小拱棚后温湿度观测资料和气象站观测资料,采用数理统计法,对不同天气条件下小拱棚温湿度变化特征和温湿度效应进行分析。结果表明:在晴天、少云-多云天气条件下小拱棚内日最高气温分别达30.0 ℃和25.0 ℃以上,且分别比小拱棚外高1.3-6.6 ℃和1.0-4.5 ℃;在晴天、少云-多云天气条件下小拱棚内日最低气温分别为4.0-11.0 ℃和6.0-14.0 ℃,比小拱棚外高0.0-1.5 ℃。小拱棚内日最小空气相对湿度为50%左右,比小拱棚外高2%-11%,日最大空气相对湿度与小拱棚外持平或略高;小拱棚内0.0 m气温和空气相对湿度日变化幅度均小于小拱棚内0.5 m。连续寡照天气时,小拱棚内气温为5.0-15.0 ℃,空气相对湿度全天为85%以上,温度、湿度变化幅度小且与小拱棚外接近或略高。总体来讲,日光温室加扣小拱棚在晴天或少云-多云天气时具有较好的增温保湿效果,但在寡照天气时增温效果不明显。温室中小拱棚内和小拱棚外温度差、湿度差在白天尤其中午前后较大,而在夜间内外相差较小或无差异。在管理上,应注意预防晴天中午前后小拱棚内温度过高引起的灼伤和寡照天气时低温高湿引起的冻害和病害。 相似文献
402.
This study presents an analysis of the spatial-temporal distribution of 230 archaeological sites in Guizhou Province, Southwest China for three selected time periods from the Paleolithic Age to the Shang-Zhou Dynasties. The relationship between archaeological sites distribution and environmental changes is also discussed based on paleo-environmental proxies of δ18O and δ13C recorded in stalagmites from Southwest China. The results show that: in the Paleolithic Age(260–10 ka BP), archaeological sites were concentrated in the central, northwestern and southwestern parts of Guizhou, where the high-altitudinal karst landforms with many natural caves suitable for human habitation are developed. In the Neolithic Age(10–3.6 ka BP), most of human settlements were concentrated in the central, northwestern and southwestern parts, while, a fewer sites were found on river terraces in the southern and eastern parts, and the intermontane basins in the central and western Guizhou. During the Shang-Zhou Dynasties(3.6–2.2 ka BP), the sites were mainly distributed in the intermontane basins and on river terraces, which were suitable for primitive aerial farming. The analysis of paleo-environmental proxies of δ18O and δ13C since 260 ka BP suggested that climate fluctuations had little impact on human settlements in this study area. The distinct physical environment, especially the spatial patterns of karst landforms and arable land played an important role in the archaeological sites distribution of Guizhou. 相似文献
403.
The temporal-spatial distribution features of prehistoric cultures since the Holocene in Zhejiang region were comparatively analyzed based on GIS spatial analysis. Results show that the prehistoric cultures expanded gradually in this region before 4000 cal. a BP. The notable expansions occurred twice, one in the Majiabang-Hemudu cultural period, the other in the Liangzhu cultural period. Meanwhile, the prehistoric cultures were disseminated from west to east coast along river valleys. After 4000 cal. a BP, as represented by the Maqiao Culture, the distributed area of each prehistoric culture contracted. This is obviously due to the termination of spreading trends to east coast, which was simultaneously accompanied by two different modes of production and economic transitions in the north and south Zhejiang region respectively. The distribution of prehistoric cultures was closely related with Holocene sea-level fluctuations, especially on the banks of Hangzhou Bay, where the distribution changes of prehistoric cultural sites were greatly affected by sea-level changes, with the closest relationships between them. After 7000 cal. a BP, the process of lowered sea-level and regression-epeirogenesis provided wider terrestrial living spaces for prehistoric inhabitants. Based on the comparative analyses of the changes of prehistoric cultures and the environmental evolution information recorded in the Qianmutian subalpine peat of Mt. Tianmu and muddy area on the inner shelf of the East China Sea, it is indicated that the changes of prehistoric cultures were synchronized with environmental changes in Zhejiang region. Before 4000 cal. a BP, the eastward expansion of prehistoric cultures in Zhejiang occurred under the background of the Holocene Optimum, and was the expansion and extension under the joint influences of agricultural civilization and maritime civilization. However, after 4000 cal. a BP, the geographical contraction of prehistoric cultures in Zhejiang occurred under the back-ground of dry-cold climate trend and deterioration of coastal marine environment. It is evidenced from the above fact that the development, expansion and contraction of prehistoric cultures are positively correlated to environmental change. The change of the climatic environment is just the underlying reason for these changes and transitions of production modes and economic forms. Therefore, the climatic environment is the dominant factor of prehistoric culture vicissitudes in Zhejiang region, which has exerted great influence on distribution, dissemination, expansion and transmutation of the culture. 相似文献
404.
内蒙古牙克石哈拉沟银金矿,位于西伯利亚板块东南古生代陆缘增生带边缘,一系列规模相对较小的中—酸性岩体侵入中生代地层中,形成基本上平行排列的细脉侵染型银金矿床。矿(化)体呈北西西走向,品位低,规模较大,受断裂和岩体共同控制。 相似文献
405.
406.
美国西北国家海洋可再生能源中心(Northwest National Marine Renewable Energy Center,NNMREC)是美国国家能源局成立的从事波浪能与潮流能开发的科研机构,目前它在波浪能和潮流能开发利用技术方面开展了许多卓有成效的工作。文章主要介绍了NNMREC在波浪能和潮流能领域的研究成果和目前开展的主要工作,并重点介绍了其太平洋海洋能源中心、移动测试平台及海洋能装置环境监测等方面的技术现状,旨在对我国的波浪能和潮流能开发利用技术尤其是海洋能试验场的建设提供积极的参考和借鉴。 相似文献
407.
408.
日光温室黄瓜小气候适宜度定量评价模型 总被引:5,自引:0,他引:5
为了定量评价日光温室内小气候对蔬菜生长发育的适宜程度,增加设施农业气象服务定量化服务内涵,文章根据实际观测资料并结合前人研究成果建立了日光温室内气温、空气相对湿度、接受到的太阳辐射及其综合因子对黄瓜生长发育的适宜度模型,运用黄瓜实际产量与适宜度的关系对模型进行检验,并实际应用了模型。得出黄瓜产量随综合小气候适宜度的增加而增加,两者相关显著,说明所建模型用于分析温室内小气候对黄瓜的适宜程度是可靠的。通过应用,得出日光温室内小气候对黄瓜生长发育最适宜的是5月,最不适宜的是1月;不论是气温适宜度、空气相对湿度适宜度、接受到的太阳辐射适宜度,还是三者综合小气候适宜度,在整个观测年度,其值的变化趋势均呈不规则“V”字形,春季适宜度最高,其次是秋季,冬季最低。计算结果与当地实际情况是一致的。 相似文献
409.
围绕塔克拉玛干沙漠腹地沙尘暴及沙尘暴前后地表沙物质的粒度特征,对塔中地区的沙尘样品开展了粒度参数计算、粒度组分分离和函数模型拟合分析。结果表明:(1)表沙样品的平均粒径为143μm,细沙和极细沙含量占87.02%;沙尘暴过后表沙样品的平均粒径为97μm,极细沙和细沙含量占79.44%。(2)沙尘暴样品的平均粒径为82μm,粉沙和极细沙含量占80.89%。(3)沙尘暴过后表沙样品的平均粒径减小46μm,黏粒、粉沙和极细沙含量增加,表明沙尘暴携带的大量细粒物质对表沙的粒度特征有重要影响。(4)沙尘暴样品粒度随高度的变化主要受控于风速,风速阈值7.7~8.4 m·s^(-1),不同高度平均粒径与平均风速的函数关系,在三维空间中采用二阶多项式曲面模型能够很好地拟合。 相似文献
410.
吐哈盆地台北凹陷水西沟群碎屑岩储层获得了高产气流,但由于储层物性较差,岩性致密,针对该储层的储集空间特征及其影响因素的研究分析对水西沟群致密砂岩层段取心的35口井,共385.2m的岩心进行样品采集,共采集样品350余块,制作铸体薄片344块,应用显微镜进行样品的微观组成特征分析;同时应用扫描电子显微镜、阴极发光仪和激光共聚焦显微镜对50余块样品深入研究。研究结果表明水西沟群储层以分选中等,磨圆较差的岩屑砂岩为主;储层压实作用强,粒间孔基本消失,主要的显孔类型为粒内溶蚀微孔,其次是基质晶间微孔和微缝,这三类微型储集空间组成了油气的主要储集空间。通过对砂岩成分组成、成岩环境,成岩作用的研究,认为吐哈盆地台北凹陷水西沟群砂岩储层早期快速压实致密化,后期在微溶蚀和压碎作用共同影响下形成了有效的"三微储集空间"。 相似文献