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961.
从气候角度提高鲜奶产量的潜力   总被引:2,自引:0,他引:2  
提出了总奶产量等于生理产奶量加营养产奶量和气候产奶量,即:Y总=Y1+Y2+Y3,并重点讨论气候产奶量Y3和营养产奶量Y2。结果表明,各月平均水汽压,月平均气温,月平均最低气温和月蒸发量4个因子对气候产奶量影响较大,同时找出1988年的各月平均水汽压,1993年月平均气温,1989年月平均最低气温和1988年月蒸发量4个最佳气象条件的相似年,它们最利用于提高气候产奶量,其次找到了低产奶原因-产乳高  相似文献   
962.
用西北地区12站1951~1996年月降水量序列,估计了分维数和平均可预报时长,初步结果表明,这些序列为具有低阶自由度(4~6)的动力系统。根据二阶Renyi熵(K2)表征的该地区平均可预报时长在2~3个月,西北地区降水分维特性可能有地域差异。  相似文献   
963.
根据河南城市大型商贸文体活动日益增多的实际需要,按不同活动对气候条件的要求,提出用单项排除和综合舒适指数两种方法来确定气候适宜期,并构建了多要素综合舒适指数的计算方法。在此基础上,以郑州为例,用以上两种方法确定了郑州举办大型社会活动的适宜的季节和日期,为决策机构提供了一项基本的气候依据。  相似文献   
964.
This paper quantitatively divides the Tang Dynasty into five prosperous and chaotic social periods,and discusses the relationship between the social division and climate change. The criteria for determining prosperity and chaos is refered to a set of systematic war data. In order to verify the reasonableness of the division,we applied 1-way-ANOVA to test the differences of each variable index between prosperity and chaos periods. The results of social division are as follows: from AD 618 to AD 626,and from AD 743 to AD 784,as well as from AD 860 to AD 907 were the chaotic periods;while from AD 627 to A0 742,and from AD 785 to AD 859 were the prosperous periods. The results of 1-way-ANOVA show that,climate change,general wars,rebellions,offensive border wars,defensive border wars,agricultural harvests,and population growth rates are all significantly different between prosperity and chaos,except the general external wars. War data were used to quantitatively represent the social changes in the Tang Dynasty. In chaotic periods,the main types of wars are rebellions and defensive border wars,while the main type of wars in prosperous periods are offensive border wars. To explore the relationship between climate change and social division means to make clear the relationship between climate change and wars. The results of correlation analysis show the decrease of agricultural harvest due to lower temperature and less precipitation leads to the shortage of resources supply,so that the likelihood of rebellions increase;while during the warm periods with abundant rainfall,increasing agricultural harvest stimulates rapid population growth. Due to the limitations of technology and land resources,offensive border wars for expansion are more likely to occur.  相似文献   
965.
Tides and short-term variabilities in the Kuroshio west of Yonakuni-jima   总被引:1,自引:0,他引:1  
INTRODUCFIONTheKuroshioeastofTaiwanIslandflowsnorthwardandenterstheEastChinaalgathroughapaSSagebetweenTaiwanIslandandlriomote-shima.TOstudyfurthertheKuroshiothereandestimateitstransPOrt,itisnecessarytoobservetheKuroshioCurrentdirectly.Therehavebeen*ThisstudywassupportedbytheNationalNaturalaudienceFoundationofChinaundercontractNo.49476278.severaldirectobservationsoftheKuroshionearTaiwanIsland.Forexample,thedirectcurrentmeasurementat(24'24'N1123'35'E)byinabaetal.(1981)showedtheapp…  相似文献   
966.
ABSTRACT. This article examines the ways in which oceans were depicted in Japanese geographical writings and maps from the Tokugawa period. It uses these texts to understand how early modern Japanese visions of the Pacific and of maritime Asian waters constructed epistemological frameworks through which the Japanese saw their place in an increasingly complex web of regional and global connections. In the absence of actual adventure on the “high seas,” Japanese writers, artists, and mapmakers used the inventive power of the imagination to fill in the cognitive blank of ocean space. I argue that the definition of early modern oceanic space was profoundly ambiguous, a legacy that, it can be argued, left its mark on Japan's modern relationship with the Asian Pacific region.  相似文献   
967.
浅水湖泊风浪过程对于湖泊生态系统具有重要的意义.基于巢湖风场、风浪和水环境参数同步高频观测结果,详细分析了快速变化风场下的风浪快速变化特征及其对湖泊水环境的影响特征.浅水湖泊风浪的有效波高和平均波周期均随风速的快速变化有较好的同步响应规律.在风速快速衰减阶段,相较有效波高,波周期有更好的稳定性.湖泊水体pH、水温、溶解氧会快速响应风浪的变化,随着风浪强度增强,对水体浊度、总磷浓度以及藻密度和生物量的扰动影响逐渐呈现.强烈的风浪扰动引起水体浊度变化的滞后时间可达3 d.快速变化的风浪场下,风浪的强烈扰动会改变水体固有的理化参数分布特征,扰动藻类常规的水体分布规律,风浪强度是造成差异的主要因子.  相似文献   
968.
水稻生长期微波介电特性研究   总被引:4,自引:0,他引:4  
利用植被介电常数的Debye-Cole双频色散模型,模拟计算了广东肇庆水稻试验区1996年晚稻和1997年早稻人插秧期、发蘖期、扬花期到成熟期各生长期的介电常数值,并根据计算结果,探讨了电磁波频率、水稻含水量、温度、含盐度及水稻冠层干体密度对介电常数的影响。其中,不同生长期水稻的介电常数各不相同,不同水稻类型(早稻和晚稻),介电常数的变化趋势不尽相同。电磁波频率、水稻含水量、温度和水稻冠层干体密度均对介电常数有不同程度的影响,而含盐度却对介电常数影响不大。  相似文献   
969.
Sea area is an important area of oil and gas exploration in China. It has been found that China’s sea area mainly consists of coal type oil and gas, and the exploration of coal-bearing series source rocks has become an important part of oil and gas exploration there. Through years of comprehensive geological research in China’s sea area, it has been revealed that it has undergone multiple occurrences of tectonic opening and closing movements in varying degrees in the Paleogene, forming 26 Cenozoic sedimentary basins of various types, such as active continental margin, passive continental margin, transitional continental margin and drift rift basins. In the present study, it is observed for the first time that coal type source rocks are mainly developed in 14 continental margin basins in China’s sea area, revealing that a very large C-shaped coal-bearing basin group developed there in the Cenozoic. Next, based on the coupling analysis of paleoclimate, paleobotany, paleogeography and paleostructure, it is observed that there are five coal-forming periods in China’s sea area, namely the Paleocene, Eocene, early Oligocene, late Oligocene and Miocene-Pliocene, and the coal-forming age is gradually new from north to south. It is also found that the coal seams in the sea area are mainly developed in three coal-forming environments in Cenozoic, namely delta, fan delta and tidal flat-lagoon. The coal seams developed in different environments are characterized by thin thickness, many layers and poor stability. However, the coal-bearing series source rocks in China’s sea area have a wide distribution range, very high thickness and large amount, thus forming a material basis for the formation of rich coal type oil and gas.  相似文献   
970.
在印度洋、大西洋沿岸,海岸工程设计波浪周期多在14 s以上,具有显著的中长周期波特征。通过以往工程项目的试验结果发现中长周期波下,规范计算的斜坡堤胸墙波浪力明显小于试验结果。因此,通过系列物理模型试验研究了中长周期波下的斜坡堤胸墙波浪力。分析斜坡坡度、肩台宽度和波浪条件对胸墙波浪力的影响。通过将试验结果与我国现有规范中的经验公式计算所得结果进行对比,发现规范更适用于胸墙底淹没的情况,而对于肩台出水情况,规范计算结果小于试验结果。由此提出了一种新的波浪力计算方法,计算准确度得到明显提高。  相似文献   
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