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15篇 您的检索式:作者名="Aifeng ZHOU"
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1A 1000-year chironomid-based salinity reconstruction from varved sediments of Sugan Lake,Qaidam Basin,arid Northwest China,and its palaeoclimatic significance显示文摘A 1000-year high-resolution(~10 years) chironomid record from varved sediments of Sugan Lake,Qaidam Basin on the northern Tibetan Plateau,is presented.The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus,and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type.Variations in the chironomid fauna and inferred salinities suggest that over the last millennium,the Sugan Lake catchment has alternated between contrasting climatic conditions,having a dry climate during the period 990―1550 AD,a relatively humid climate during the Little Ice Age(LIA)(1550―1840 AD),and a dry climate again from 1840 AD onwards.At the decadal to centennial scale,a wet event around 1200―1230 AD,interrupting the generally arid period(990―1550 AD),and a dry event around 1590―1700 AD,punctuating the generally humid period(1550―1840 AD),are clearly documented.Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency.The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China(ANC).The LIA,characterized by generally humid conditions over the west-erly-dominated ANC was distinctly different from that in monsoonal China,implying an 'out-of-phase' relationship between moisture evolution in these two regions during the past 1000 years.CHEN JianHui CHEN FaHu ZHANG EnLou BROOKS Stephen J ZHOU AiFeng ZHANG JiaWu 2009Chinese Science Bulletin2009,54,20:20
2Climatic changes documented by stable isotopes of sedimentary carbonate in Lake Sugan,northeastern Tibetan Plateau of China,since 2 kaBP显示文摘Lake Sugan at the northern edge of the Qaidam Basin was selected as the research object. The temporal se-quence of sedimentary cores retrieved from Lake Sugan since 2 kaBP was reconstructed using the 210Pb, AMS 14C and conventional 14C dating methods. Carbon and oxygen iso-topes of carbonate in the fine-grained lake sediments were analysed. Combined with the changes of δ 18O values of sur-face water and air temperature observation data in the study area, it might be thought that the δ 18O value of the carbon-ate indicates effective moisture, and the changes in δ 13C val-ues are related to annual freeze-up duration of the lake and indirectly indicate air temperature changes in winter half year. From the above, the sequence of climatic changes in the region since 2 kaBP was established. The climatic changes experienced five stages: Warm-dry climate during 0-190 AD; cold-dry climate during 190-580 AD; warm-dry cli-mate during 580-1200 AD (MWP); cold-wet climate during 1200-1880 AD (LIA); cold-dry climate during 1880-1950 AD; and climate warming since 1950s. The air temperature changes in winter half year reflected by carbon isotope since 2 kaBP are in good agreement with the historical literature records and other geologic records, which shows that the climate changes recorded by the stable isotopes from Lake Sugan since 2 kaBP are of universal significance.QIANG Mingrui CHEN Fahu ZHANG Jiawu GAO Shang-yu ZHOU Aifeng 2005Chinese Science Bulletin2005,50,17:19
3The discovery of annually laminated sediments (varves) from shallow Sugan Lake in inland arid China and their paleoclimatic significance显示文摘Detailed examination of sedimentary cores retrieved from Sugan Lake in the northern Qaidam Basin of northwest China’s Tibetan Plateau reveal that fine laminated beddings form in the sediments where water depth exceeds 3 m. Seasonal surface sediments trapped at the bottom of the lake suggest that sediments deposited during summer and autumn are mainly light colored monohydrocalcites, while those deposited in winter are dark organic matter, indicating that varve layers form under modern limnological conditions. Continuous varve sediments comprising four types have accumulated in the upper 5.5 m of Core SG03I from the center of the lake. All types exhibit clear seasonality indicative of annual deposition. Varve counts correspondence with 210Pb dates on recent sediments in the upper core suggest the continuous varves of the upper 5.5 m of the core formed in the late Holocene (2670 a BP). The Sugan Lake varve sequence is the first demonstration of annually laminated sediments re-ported in arid western China.ZHOU AiFeng CHEN FaHu QIANG MingRui YANG MeiLin ZHANG JiaWu 2007Science China Earth Sciences2007,50,8:17
4Spatial and temporal variation in magnetic properties of street dust in Lanzhou City,China显示文摘Urban environmental problems are of increasing concern. Lanzhou is a large industrial city in North-west China. Street dust samples representing different temporal and spatial scales were collected for magnetic properties study. Magnetic measurements indicate a high concentration of magnetic minerals in Lanzhou street dust, dominated by pseudo-single domain (PSD) magnetite. The concentration of magnetic materials is distinctly high in winter and spring, low in autumn. Similarly, higher concentra-tions associated with heavy industry, concentrated residential development, and vehicular traffic sug-gest mixed contributions of magnetic material from both anthropogenic and natural sources. χ_lf and SOFT% are effective magnetic parameters that denote seasonal differences among magnetic proper-ties in street dust, convenient and economical methods for monitoring street dust pollution.WANG Guan XIA DunSheng LIU XiuMing CHEN FaHu YU Ye YANG LiPing CHEN JianHui ZHOU AiFeng 2008Chinese Science Bulletin2008,53,12:7
5Multiple evidences indicate no relationship between prehistoric disasters in Lajia site and outburst flood in upper Yellow River valley, China显示文摘All around the world, ancient legends exist about the Great Flood, and the influence of the Great Flood in human evolutionary history is a hotly debated topic. In China, the legend of the prehistoric Great Flood and Yu the Great's flood control has a long history and is considered to be closely linked to the establishment of the Xia Dynasty. However, there is a lack of solid scientific evidence. Against this issue, some scholars have proposed that an earthquake around 1920 BCE in the Guanting Basin along the upper reaches of the Yellow River led to the creation of a lake by damming in the Jishi Gorge and that the outburst of water from that lake led to the massive flood in the Yellow River region. These studies provided new scientific evidence for the Chinese legend. In this paper, we date skeletal samples embedded in earthquake sand blasting from the Lajia site, analyze remains from natural disasters(such as earthquakes and floods) and also archaeological remains. In addition, we compared the skeletal samples dating with that of sediments from the dammed-up lake. Our results are inconsistent with those of previous scholars. The earthquake at the Lajia site occurred no earlier than 1800 BCE, and the dammed-up lake in Jishi Gorge had disappeared by 3600 BCE. Thus, the formation and outburst of the dammed lake, the sudden death of ancient humans at the Lajia site and the ancient earthquake were independent events occurring at different times. In addition, the massive flood in the upper reaches of the Yellow River did not actually happen. Thus, we argue against and invalidate the hypothesis that the massive flood was related to Yu the Great's flood control and the establishment of the Xia Dynasty.DONG GuangHui ZHANG FanYu LIU FengWen ZHANG DongJu ZHOU AiFeng YANG YiShi WANG GongHui 2018Science China Earth Sciences2018,61,4:7
6A novel procedure for pollen-based quantitative paleoclimate reconstructions and its application in China显示文摘Traditionally, the evaluation of pollen-based quantitative paleoclimate reconstructions focuses on the ability of calibration sets to infer present climatic conditions and/or the similarity between fossil and modern assemblages. Objective criteria for choosing the most appropriate climate parameter(s) to be reconstructed at a specific site are thus lacking. Using a novel approach for testing the statistical significance of a quantitative reconstruction using random environmental data, in combination with the advantageous large environmental gradients, abundant vegetation types and comprehensive modern pollen databases in China, we describe a new procedure for pollen-based quantitative paleoclimatic reconstructions. First, the most significant environmental variable controlling the fossil pollen assemblage changes is identified. Second, a calibration set to infer changes in this targeted variable is built up, by limiting the modern ranges of other environmental variables. Finally, the pollen-based quantitative reconstruction is obtained and its statistical significance assessed. This novel procedure was used to reconstruct the mean annual precipitation(Pann) from Gonghai Lake in the Lvliang Mountains, and Tianchi Lake in the Liupan Mountains, on the eastern and western fringe of the Chinese Loess Plateau, respectively. Both Pann reconstructions are statistically significant(p<0.001), and a sound and stable correlation relationship exists in their common period, showing a rapid precipitation decrease since 3300 cal yr BP. Thus, we propose that this procedure has great potential for reducing the uncertainties associated with pollen-based quantitative paleoclimatic reconstructions in China.CHEN JianHui LV FeiYa HUANG XiaoZhong H.John B.BIRKS Richard J.TELFORD ZHANG ShengRui XU QingHai ZHAO Yan WANG HaiPeng ZHOU AiFeng HUANG Wei LIU JianBao WEI GuoYing 2017Science China Earth Sciences2017,60,11:6
7Effects of climate change and human activity on lake shrinkage in Gonghe Basin of northeastern Tibetan Plateau during the past 60 years显示文摘Changes in the status of freshwater resources are a topic of major global,regional and local concern.This is especially so in the arid and semi-arid regions of China,where shortage of water resources plays a crucial role in limiting sustainable socioeconomic development,as well as in sustaining natural ecosystems.Recent climate change,as well as the effects of localized human activity,such as the use of water for irrigation agriculture,may have significant effects on the status of the water resources in the region.Here,we report the results of a study of changes in the areas of lakes in Gonghe Basin,northeastern Tibetan Plateau of China,over the last 60 years.The data were acquired from optical satellite images and demonstrate that the total water area of lakes in Gonghe Basin decreased significantly from the 1950 s to 1980 s.The cause is ascribed mainly to human activity including exploitation of farmland,against a background of increasing population;in addition,climatic data for the region demonstrate a minor drying trend during this period as the temperature increased slightly.After the construction of several reservoirs,significant amounts of water were redistributed to promote irrigation agriculture and we conclude that this caused a significant shrinkage of the natural lakes.However,both the area of farmland and the population size remained approximately constant after 1990.We conclude that the variation of the total area of lakes during the second period was mainly controlled by climatic factors(precipitation and temperature).As the regional temperature reached a new high,the area of some of the lakes decreased sharply before finally maintaining a relatively steady state.We emphasize that anthropogenic climate change and human activity have both significantly influenced the status of water resources in the arid and semi-arid regions of China.WU Duo CHEN Fahu LI Kai XIE Yaowen ZHANG Jiawu ZHOU Aifeng 2016Journal of Arid Land2016,8,4:6
8Investigating natural drivers of vegetation coverage variation using MODIS imagery in Qinghai, China显示文摘The climatically sensitive Qinghai province of China has been recognized as a hotspot for studies on the feedbacks of terrestrial ecosystems to global climate change. Thus, investigating vegetation coverage and its natural drivers in Qinghai is an important focus of ecosystem research. On the basis of Moderate Resolution Imaging Spectroradiometer(MODIS) Enhanced Vegetation Index(EVI) time series data, we estimated the vegetation coverage in this region using the dimidiate pixel model. Trend analyses, correlations between meteorological parameters, changes in vegetation coverage, and the temporal and spatial relationships between soil texture and vegetation coverage were used to investigate the possible drivers of vegetation coverage variations. The results indicated that the reduction of vegetation coverage slowed down in the period from 2000 to 2012. Annual mean temperature was the main climatic driver of the total extremely low and low vegetation coverage areas in Qinghai, followed by the precipitation anomalies. The extremely low and low vegetation coverage areas were mainly distributed in regions with a mean annual relative air humidity of <40% and the spatial distributions of these two area types differentiated along the 200-mm rainfall contours. The total extremely low and low vegetation coverage areas were mainly characterized by sandy clay loam soil, followed by loamy sand and sandy soil. Regions with sandy loam or loam soil have the greatest risk of vegetation coverage reductions. Knowledge of vegetation coverage variation and its natural drivers in the ecologically fragile region of Qinghai can provide scientific support for managing environmental change and desertification.ZHOU Lei LYU Aifeng 2016Journal of Arid Land2016,8,1:6
9Spatiotemporal variations of aridity in China during 1961–2015: decomposition and attribution显示文摘Changes in global climate intensify the hydrological cycle, directly influence precipitation, evaporation,runoff, and cause the re-distribution of water resources in time and space. The aridity index (AI), defined as the ratio of annual precipitation to annual potential evapotranspiration, is a widely used numerical indicator to quantify the degree of dryness at a given location. This study examined the effects of climate change on AI in China during 1961–2015. The results showed that the nationally averaged AI experienced a notable interdecadal transition in 1993, characterized by increasing AI (wetter) between 1961 and 1993,and decreasing AI (drier) after 1993. Overall, the decreased solar radiation (solar dimming) was the main factor affected the nationally averaged AI during 1961–1993, while the relative humidity dominated the variations of nationally averaged AI during 1993–2015. However, the roles of individual factors on the changes in AI vary in different subregions. Precipitation is one of the important contributing factors for the changes of AI in almost all subregions, except the Mid-Lower Yangtze and Huaihe basins. Solar radiation has been significantly decreased during 1961–1993 in South China, Southwest China, Mid-Lower Yangtze and Huaihe basins, and the Tibetan Plateau. Therefore, it dominated the trends of AI in these subregions.The relative humidity mainly affected the Mid-Lower Yangtze and Huaihe basins, Southwest China, and the Tibetan Plateau during 1993–2015, hence dominated the trends of AI in these subregions. The changes of temperature and wind speed, however, played a relatively weak role in the variations of AI.Chang Liu Wei Huang Song Feng Jianhui Chen Aifeng Zhou 2018Science Bulletin2018,63,18:5
10Emergence of ancient cities in relation to geopolitical circumstances and climate change during late Holocene in northeastern Tibetan Plateau, China显示文摘Guanghui DONG Honggao LIU Yishi YANG Ying YANG Aifeng ZHOU Zhongxin WANG XiaoyanREN Fahu CHEN 2016Frontiers of Earth Science2016,10,4:4
11A facile synthetic route to flower-like NiO and its catalytic properties显示文摘Zhou Dishan Yan Aifeng Wu Ying 2013Indian Joumal of Chemis- try2013,52,1:1
12Comparison of remotely sensed and meteorological data-derived drought indices in mid-eastern China显示文摘Lei Zhou Jie Zhang Jianjun Wu Lin Zhao Ming Liu Aifeng Zhitao Wu 2012International Journal of Remote Sensing2012,,6:1
13Construction of a HERG mutant L539fs/47-*558W pEGFP vector and the expression of the fusion protein in HEK293 cells显示文摘Objective:To construct a human ether-a-go-go-related gene(HERG)nonsense mutant L539fs/47-*558W into the autonomously fluorescent,eukaryotic expression vector pEGFP-C2,and to verify expression of the reconstruct in human embryonic kidney-293(HEK293)cells.Methods:The mutational fragment was subcloned into pEGFP-C2-HERG by double digestion of SbfⅠ,Eco91Ⅰand rejoining of T4 ligase.After verification,the recombinant pEGFP-C2-L539fs/47-*558W and pEGFP-C2-HERG were respectively transfected into HEK293 cells for 48 h by the Lipofect method to observe the expression location of the fusion protein by laser confocal imaging scanning in vivo.pcDNA3-L539fs/47-*558W and pcDNA3-HERG were transfected to observe the expression location of the HERG protein by immunofluoresceoce.The mutant protein size was determined by Western blotting.Results:The about 1 kb-sized mutation region cDNA fragment from pcDNA3-L539fs/47-*558W and the about 7.2 kb-sized target vector fragment from pcDNA3-HERG were ligated after purification and gel recovery.pEGFP-C2-L539fs/47*-558W,approximately 8.2 kb,was demonstrated successfully been constructed under agarose gel electrophoresis and further sequencing.Laser confocal imaging showed that pEGFP-C2-HERG was mainly expressed in the membrane,whereas truncated mutant-type HERG in the pEGFP-C2 vector was partially located in the cytoplasm,the others were transported to the cell membrane in living HEK293 cells.The same as the immunofluoresceoce results after transfection of pcDNA3-HERG and pcDNA3-L539fs/47-558W.Wild-type HERG-GFP fusion protein expressed 160 and 180 kDa bands.The mutant and mutant-GFP fusion proteins were 70 and 100 kDa,respectively.Conclusion:pEGFP-C2-L539fs/47-*558W was successfully constructed by double digestion method GFP had no effect on its protein expression and trafficking in HEK293 cells,which laid a foundation for the further study on L539fs/47-*558W.ZHANG Junbo Lü Ying ZHANG Aifeng SUN Chaofeng HAN Wenqi LI Guoliang GAO Jie HUO Jianhua PAN Junqiang ZHOU Xin NIU Xiaolin 2013Journal of Medical Colleges of PLA(China)2013,28,4:0
14Doctors' faith显示文摘We make some efforts to find some connections between religion and medical science. Medical science can be regarded as sacred and holy as a religion for doctors to believe. The common points between them are the basis to successfully integrate them into doctors' faith. Furthermore, we explain that doctors need a faith to believe so as to meet the demand of humanitarian traits we should have and to do better in the scientific work and win in the battles with the diseases.ZHANG Junbo Lü Ying ZHANG Aifeng SUN Chaofeng HAN Wenqi LI Guoliang GAO Jie HUO Jianhua PAN Junqiang ZHOU Xin NIU Xiaolin 2013Journal of Medical Colleges of PLA(China)2013,28,1:0
15Reliability of radiocarbon dating on various fractions of loess-soil sequence for Dadiwan section in the western Chinese Loess Plateau显示文摘黄土土壤序列标明日期的精确放射性碳在最后冻结成冰和 Holocene 期间在大陆人背景在环境、气候的变化的重建起一个必要作用。然而,我们土壤和黄土样品的各种各样的部分的放射性碳年龄的可靠性的知识仍然是不够的。这里,我们在场我们在放射性碳年龄的学习结果在西方的中国黄土高原从 loess-paleosol 节基于样品的体积有机物, humin 部分,和碳酸盐收集了。我们把这些观察与光学地刺激的光年龄和炭放射性碳年龄作比较评估这些部分的可靠性。我们观察到 humin 部分的放射性碳年龄离炭的那些很靠近并且与在试验性的错误以内的光学地刺激的光年龄一致。我们观察到在从那些的碳酸盐和炭和光学地刺激的光的体积有机物的放射性碳年龄的重要偏差变老,由于这些部分的冲淡可能在 pedogenetic 过程期间。我们的结果表明除了炭, humin 部分可以让步可靠 < 啜 class= “ a-plus-plus ” > 14 为中国黄土土壤顺序的 C 年龄。Zongli WANG Hui ZHAO Guanghui DONG Aifeng ZHOU Jianbao LIU Dongju ZHANG 2014Frontiers of Earth Science2014,8,4:0
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