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Reconstruction of hydrological changes based on tree-ring data of the Haba River, northwestern China 被引量:10
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作者 zhang tongwen yuan yujiang +4 位作者 chen feng yu shulong zhang ruibo qin li jiang shengxia 《Journal of Arid Land》 SCIE CSCD 2018年第1期53-67,共15页
Reconstructing the hydrological change based on dendrohydrological data has important implications for understanding the dynamic distribution and evolution pattern of a given river. The widespread, long-living conifer... Reconstructing the hydrological change based on dendrohydrological data has important implications for understanding the dynamic distribution and evolution pattern of a given river. The widespread, long-living coniferous forests on the Altay Mountains provide a good example for carrying out the dendrohydrological studies. In this study, a regional composite tree-ring width chronology developed by Lariat sibirica Ledeb. and Picea obovata Ledeb. was used to reconstruct a 301-year annual (from preceding July to succeeding June) streamflow for the Haba River, which originates in the southern Altay Mountains, Xinjiang, China. Results indicated that the reconstructed streamflow series and the observations were fitting well, and explained 47.5% of the variation in the observed streamflow of 1957-2008. Moreover, floods and droughts in 1949-2000 were precisely captured by the streamflow reconstruction. Based on the frequencies of the wettest/driest years and decades, we identified the 19th century as the century with the largest occurrence of hydrological fluctuations for the last 300 years. After applying a 21-year moving average, we found five wet (1724-1758, 1780-1810, 1822-1853, 1931-1967, and 1986-2004) and four dry (1759-1779, 1811-1821, 1854-1930, and 1968-1985) periods in the streamflow reconstruction. Furthermore, four periods (1770-1796, 1816-1836, 1884-1949, and 1973-1997) identified by the streamflow series had an obvious increasing trend. The increasing trend of streamflow since the 1970s was the biggest in the last 300 years and coincided with the recent warming-wetting trend in northwestern China. A significant correlation between streamflow and precipitation in the Altay Mountains indicated that the streamflow reconstruction contained not only local, but also broad-scale, hydro-climatic signals. The 24-year, 12-year, and 2.2-4.5-year cycles of the reconstruction revealed that the streamflow variability of the Haba River may be influenced by solar activity and the atmosphere-ocean system. 展开更多
关键词 larzx sibiffca Ledeb. Picea obovata Ledeb. streamflow reconstruction tree-ring width Altay Mountains
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超声降解落叶松中阿拉伯半乳聚糖及其活性的研究 被引量:5
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作者 郭怡帆 林圣翔 +1 位作者 刘焕燕 贺亮 《中国林副特产》 2018年第1期8-11,14,共5页
以落叶松[Larix gmelinii(Rupr.)Kuzen]的木屑为原料提取阿拉伯半乳聚糖(AG、松针多糖),然后用超声法对所提取的阿拉伯半乳聚糖进行降解。以降解松针多糖对自由基清除率为检测指标,通过单因素试验考察超声功率、降解温度、降解时间、料... 以落叶松[Larix gmelinii(Rupr.)Kuzen]的木屑为原料提取阿拉伯半乳聚糖(AG、松针多糖),然后用超声法对所提取的阿拉伯半乳聚糖进行降解。以降解松针多糖对自由基清除率为检测指标,通过单因素试验考察超声功率、降解温度、降解时间、料液比对松针多糖体外抗氧化活性的影响。再利用正交试验确定的最佳降解条件为:降解温度70℃、降解时间2.0h、料液比1∶250、功率150W。在抗氧化活性方面,松针多糖质量浓度越高,对·OH清除率越高,且降解后比降解前在清除·OH和DPPH上有一定提高。 展开更多
关键词 落叶松 阿拉伯半乳聚糖 超声降解 自由基清除能力 抗氧化活性
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