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Amplitudes, rates, periodicities, causes and future trends of temperature variations based on tree rings for the past 2485 years on the central-eastern Tibetan Plateau were analyzed. The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period, Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343-425 AD), and not in the late 20th century. There were significant cycles of 1324 a, 800 a, 199 a, 110 a and 2-3 a in the 2485-year temperature series. The 1324 a, 800 a, 199 a and 110 a cycles are associated with solar activity, which greatly affects the Earth surface temperature. The long-term trends (>1000 a) of temperature were controlled by the millennium-scale cycle, and amplitudes were dominated by multi-century cycles. Moreover, cold intervals corresponded to sunspot minimums. The prediction indicated that the temperature will decrease in the future until to 2068 AD and then increase again.  相似文献   
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比例阀应用     
分析了加热炉步进装置液压比例控制系统比例阀的斜坡时间,计算了比例阀口压差以及用比例阀控制时液压缸有效作用面积和液压泵压力,对于计算值给出了相应的测试结果。  相似文献   
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Cai  QiuFang  Liu  Yu  Bao  Guang  Lei  Ying  Sun  Bo 《科学通报(英文版)》2010,55(26):3008-3014
As a consequence of recent global warming and its social impact, regional climate change is attracting an increasing amount of attention from scientists. A May-July temperature proxy extending back to 1836 was developed from tree-ring width of Chinese pine (Pinus tabulaeformis Carr.) found in the middle Lüliang Mountains, northern China. Correlations with climatic data from six nearby meteorological stations range from −0.58 to −0.65, indicating a strong response of tree-ring index to May-July mean tem-peratures, which were subsequently reconstructed. The reconstruction captures 45% (F=38.474, P<0.001) of the regional variance in the instrumental data over the calibration period 1955–2003. Reconstructed warm and cold periods were verified by additional temperature reconstructions based on tree-ring data from northern China. In addition, the reconstruction was significantly correlated with May-July mean temperatures from 13 other meteorological stations in northern China, suggesting that our reconstruction is also representative of north-central China. The warming trend during the second half of the 20th century is seen in the reconstruction, but only the 1994–2002 mean temperature seems unprecedented over the whole reconstructed period.  相似文献   
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Cognition and emotion have long been thought of as independent systems. However, recent research in the cognitive and neurobiological sciences has shown that the relationship between cognition and emotion is more interdependent than separate. Based on evidence from behavioral and neuroscientific research, researchers have realized that it is necessary to propose a new conceptual framework to describe the relationship between cognition and emotion. In this article, recent research from behavioral, neuroscientific and developmental research on the interaction between cognition and emotion is summarized, and how the interaction of cognition and emotion might affect computer science and artificial intelligence is discussed. It especially focuses on the implications for affective computing.  相似文献   
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A tree-ring-width chronology of Pinus tabulaeformis from Kalaqin, Inner Mongolia was developed using modern dendrochronological techniques. Based on the results of correlation function analysis, the total precipitation from the previous August to current July was reconstructed for 1771?C2008 AD with an explained variance of 49.3%. The reconstruction correlated well with the dryness/wetness series derived from historical documents, as well as the precipitation reconstruction of the Chifeng-Weichang region. There were eight intervals with greater precipitation than the average (associated with the strong East Asian summer monsoon) and seven intervals lower than the average (weak monsoon). A power spectrum analysis showed that there were 120 a, 80 a, 8 a and 2 a periodicities.  相似文献   
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Amplitudes, rates, periodicities, causes and future trends of temperature variations based on tree rings for the past 2485 years on the central-eastern Tibetan Plateau were analyzed. The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period, Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343?C425 AD), and not in the late 20th century. There were significant cycles of 1324 a, 800 a, 199 a, 110 a and 2?C3 a in the 2485-year temperature series. The 1324 a, 800 a, 199 a and 110 a cycles are associated with solar activity, which greatly affects the Earth surface temperature. The long-term trends (>1000 a) of temperature were controlled by the millennium-scale cycle, and amplitudes were dominated by multi-century cycles. Moreover, cold intervals corresponded to sunspot minimums. The prediction indicated that the temperature will decrease in the future until to 2068 AD and then increase again.  相似文献   
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High-frequency samples have been collected at Jiangjia Spring, the outlet of Qingmuguan underground river system (QURS) in Chongqing in late April, 2008. The variations of hydrogeochemical compositions are found responding rapidly to storm events. Principal component analysis (PCA) of the 20 variables is employed to interpret the relationships with specific processes that control the groundwater hydrogeochemical formations. Through PCA, 84.961% of the total amount information is extracted to indicate the fo...  相似文献   
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