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Quantitative studies on charcoalification:Physical and chemical changes of charring wood

Fundamental Research 2024年第1期4卷 113-122页

作者： Gang Li Linlin Gao fengwen liu Menghan Qiu Guanghui Dong MOE Key Laboratory of Western China's Environmental Systems College of Earth&Environmental SciencesLanzhou UniversityLanzhou 730000China Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environment ScienceYunnan UniversityKunming 650504China

Charcoal is commonly preserved in both natural and artificial sediments,and is intensively used in paleontological,paleoenvironmental,and archaeological studies due to the abundant bio-information it contains.The biochemical properties of charcoal are also used for paleoclimatic reconstruction;however,the reliability of this approach has been challenged due to a lack of clarity on how physicochemical properties change during the charring process,as well as the temperatures required for charcoalification.To address this lack,in this study,Qinghai spruce and Chinese pine wood samples from the northeastern Tibetan Plateau were heated at different temperatures and for different lengths of time under restricted oxygen conditions.The reflectance;carbon,nitrogen,and oxygen content;and tracheid morphology were quantified before and after heating to assess changes related to the charring process.Archaeological charcoal remains were then evaluated to determine the charcoalification temperatures by comparing with the experimental results.The minimum temperature required for wood charcoalification was∼300℃,while temperatures recorded by archaeological charcoal were concentrated at 400-500℃.During the charring experiments,the tracheid cell walls gradually homogenized,and tracheid cell wall thickness and lumen area decreased by∼20%.On average,50%mass losses were observed;the carbon and oxygen content(%wt.)approximately changed from 47%to 60%and 48%to 35%respectively,while the nitrogen content(%wt.)fluctuated around 0.2%.The reflectance increased slightly from 0%to 0.5%.We propose that the charcoalification of wood tissue refers to charring(in restricted air)and carbonization(in the almost absence of air)when the wood is exposed to a heat source,which then finally transforms into a black,inert solid.This quantitative study provided valuable data and a thorough assessment of the process of wood charcoalification,as well as accurately estimated the feasibility of using charcoal physicochemical properties in paleoclimatic research

关键词： Charcoalification Quantitative study Charcoal formation Archaeological charcoal Tracheid cell wall thickness Reflectance

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Environmental and technological effects on ancient social evolution at different spatial scales

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Science China Earth Sciences 2017年第12期60卷 2067-2077页

作者： DONG GuangHui liu fengwen CHEN FaHu MOE Key Laboratory of Western China's Environmental Systems(Ministry of Education) Lanzhou UniversityLanzhou 730000China

The rise and fall of ancient cultures and civilizations is a hotly debated topic that has generated disagreements and disputes. In this paper we summarize some case studies on the abandonment of ancient sites, the prosperity and collapse of ancient cultures, and demographic changes, as well as the influence of environment and technology during the prehistoric and historic periods. We then suggest that the dominant influencing factors for the evolution of ancient societies vary by spatial scale.At the local scale, sudden disasters are critical factors leading to the destruction and abandonment of large settlements. On a regional scale, climatic variations(e.g., droughts or cold events lasting for decades or centuries) are important factors that induce the collapse of ancient civilizations and mass migrations, while an enduring and stable optimal climate facilitated the prosperity of ancient civilizations. On a global scale, major technological innovations and their dispersion lasting for centuries and even millennia are major catalysts for population growth and social development. Lastly, we illustrate a possible mechanism under which environmental and technological factors played a critical role in ancient human survival and social evolution on different spatial scales.

关键词： Prehistoric period Historic period Man-land relationship Cultural evolution Sudden disaster Climatic variation Technological innovation

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Multiple evidences indicate no relationship between prehistoric disasters in Lajia site and outburst flood in upper Yellow River valley, China

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Science China Earth Sciences 2018年第4期61卷 441-449页

作者： DONG GuangHui ZHANG FanYu liu fengwen ZHANG DongJu ZHOU AiFeng YANG YiShi WANG GongHui MOE Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou University Key Laboratory of Mechanics on Disaster and Environment in Western China (Ministry of Education) Department of Geological EngineeringLanzhou University Research Center on Landslides Disaster Prevention Research InstituteKyoto University

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.

关键词：科学证据大洪水自然灾难黄河爆发地点中国山谷

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Prehistoric agriculture development in the Yunnan-Guizhou Plateau, southwest China： Archaeobotanical evidence

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Science China Earth Sciences 2016年第8期59卷 1562-1573页

作者： LI HaiMing ZUO XinXin KANG LiHong REN LeLe liu fengwen liu HongGao ZHANG NaiMeng MIN Rui liu Xu DONG GuangHui Key Laboratory of Western China’s Environmental Systems (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Lanzhou 730000 China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Yunnan Province Institute of Cultural Relics and Archaeology Kunming 650118 China College of Agronomy and Biotechnology Yunnan Agricultural University Kunming 650201 China

The origin, development and expansion of prehistoric agriculture in East Asia have been widely investigated over the past two decades using archaeobotanical analysis from excavated Neolithic and Bronze Age sites. Research on prehistoric agriculture has predominantly focused in the valleys of the Yellow River and the Yangtze River. Agricultural development during the Neolithic and Bronze Age periods in the Yunnan-Guizhou Plateau of southwest China, an important passageway for human migration into Southeast Asia, still remains unclear. In this paper, based on macrofossil and microfossil analysis and radiocarbon dating at the Shilinggang site, we investigate plant subsistence strategies in the Nujiang River valley during the Bronze Age period. Combined with previous archaeobotanical studies in the Yunnan-Guizhou Plateau, we explore agricultural development processes in this area during the Neolithic and Bronze Age. Our results indicate that rice and foxtail millet were cultivated in Shilinggang around 2500 cal a BP. Three phases of prehistoric agricultural development in the Yunnan-Guizhou Plateau can be identified: rice cultivation from 4800–3900 cal a BP, mixed rice and millet crop(foxtail millet and broomcorn millet) cultivation from 3900–3400 cal a BP, and mixed rice, millet crop and wheat cultivation from 3400–2300 cal a BP. The development of agriculture in the Yunnan-Guizhou Plateau during the Neolithic and Bronze Age periods was primarily promoted by prehistoric agriculture expansion across Eurasia, agricultural expansion which was also affected by the topographic and hydrological characteristics of the area.

关键词： Nujiang River valley Yunnan-Guizhou Plateau Neolithic Bronze Age Macrofossil analysis Phytolith analysis Radiocarbon dating

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Detecting anthropogenic impact on forest succession from the perspective of wood exploitation on the northeast Tibetan Plateau during the late prehistoric period

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Science China Earth Sciences 2022年第11期65卷 2068-2082页

作者： fengwen liu Shanjia ZHANG Hucai ZHANG Guanghui DONG Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environment ScienceYunnan UniversityKunming 650504China Ministry of Education Key Laboratory of Western China's Environmental System College of Earth&Environmental SciencesLanzhou UniversityLanzhou 730000China

Human activities are usually considered to have had impacts on forest degradation and/or changes of forest composition in the past.The Tibetan Plateau,an environmentally sensitive area,has witnessed a high intensity of human activities since the late Neolithic,but the evidence is still incomplete concerning how human activities affected the environment,especially vegetation changes.This may result,in part,from the fact that research on prehistoric wood utilization by humans in the northeast Tibetan Plateau(NETP)is scarce,especially from the perspective of charcoal analysis,which is an archaeological index directly related to human activities.To fill this gap,we report new data here concerning charcoal analysis from 24 archaeological sites dated 5200–2300 a BP in the NETP,where this period saw remarkable environmental and social changes.By coupling the results with published paleoenvironment records(especially pollen),we aim to explore the utilization of wood and its spatial-temporal changes,as well as the anthropogenic impacts on past forest dynamics in the NETP.The results suggest that the wood resources collected by humans were mainly needleleaf trees(Picea L.and Pinus L.),broadleaved trees(Populus L.,Salix L.,and Betula)as well as shrubs(Hippophae L.and Tamarix L.),and that these were distributed around the human habitation areas.There was a clear spatial difference in the woody assemblage collected by humans in the period 3600–2300 a BP.This was likely related to the diversity of natural environments in local areas,but there was an abnormal spatial pattern of forest composition with broadleaved trees dominant above 2500 masl caused not by climate change,but by the rapid increase of human settlement and wood collection in high altitude areas of the NETP since 3600 a BP.

关键词： Charcoal records Late prehistoric period Northeast Tibetan Plateau Climate change Anthropogenic impacts

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Spatiotemporal variation of agricultural patterns in different geomorphologic and climatic environments in the eastern Loess Plateau,north-central China during the late Neolithic and Bronze Ages

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Science China Earth Sciences 2022年第5期65卷 934-948页

作者： Haiming LI Yifu CUI Nathaniel JAMES Melissa RITCHEY fengwen liu Junna ZHANG Minmin MA Guanghui DONG College of Humanities&Social Development Nanjing Agricultural UniversityNanjing 210095China Institution of Chinese Agricultural Civilization Nanjing Agricultural UniversityNanjing 210095China Agricultural Archaeology Research Center Nanjing Agricultural UniversityNanjing 210095China College of Tourism Huaqiao UniversityQuanzhou 362021China Ministry of Education Key Laboratory of Western China’s Environmental System College of Earth&Environmental SciencesLanzhou UniversityLanzhou 730000China Department of Anthropology University of California San DiegoSan DiegoCA 92093USA Department of Anthropology Washington University in St.LouisSt.LouisMO 63130USA Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environment ScienceYunnan UniversityKunming 650504China Laboratory for Environmental Archaeology Archaeological Research CenterBeijing Union UniversityBeijing 100191China

Human settlement and agricultural development are closely linked to local geomorphological and climatic environments.However,the variation in agricultural systems in different environmental and prehistoric contexts remains unknown.We report new archaeobotanical and radiocarbon dates from 34 Neolithic and Bronze Age sites in the Hutuo River Valley(HTRV)in north-central China and compare them with updated archaeobotanical studies in the Sushui River Valley(SSRV)and Henan Province(HNP),to explore the similarities and differences of agricultural patterns under different geomorphologic and climatic environments in north-central China.Our results reveal that humans consistently cultivated foxtail and broomcorn millet in the HTRV from the Miaodigou(6000–5700 cal.a BP)to the Shang-Zhou(3600–2256 cal.a BP)period,despite the introduction of wheat and barley into the area around 4000 a BP.Climate conditions and hilly landforms in the HTRV,SSRV and some parts of the HNP led people to develop foxtail and broomcorn millet dry land farming practices between 7000 and 3000 a BP.Alternatively,in other areas of the HNP,the climate conditions and alluvial plains enabled people to develop a mixed agriculture of millets,soybeans,and rice from 7000 to 4000 a BP,with the addition of wheat between 4000 and 3000 a BP.Farmers’different agricultural technologies and interactions with foreign cultures may have also influenced the formation of different agricultural patterns in the three regions between 7000 and 3000 a BP.Population growth during 7000–3000 a BP can explain the overall propensity of the higher-yield foxtail millet rather than broomcorn millet as the main cultivated crop.In the HTRV,however,higher proportions of broomcorn millet(as compared to the SSRV and HNP),may reflect the greater drought and heat tolerance of broomcorn millet,representing an adaptive agricultural strategy in the river valley.

关键词： Archaeobotanical Agricultural patterns Climate conditions Hilly area Alluvial plains

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Transcription factor SsSte12 is involved in Sclerotia development and appressoria production in Sclerotinia sclerotiorum

Transcription factor SsSte12 is involved in Sclerotia develo...

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中国植物病理学会第十一届全国会员代表大会暨2018年学...

作者： Lu Dongxu liu fengwen Sun Rongze Wang Kangning Zhang Bowen Zhang Yanhua Pan Hongyu College of Plant Sciences Jilin University

Sclerotinia sclerotiorum is a challenging agricultural pathogen for management,causing large global economic losses annually.The sclerotia and infection cushions are critical for its long-term survival and successful penetration on a wide spectrum of hosts.The mitogen-activated protein kinase（MAPK） cascades serve as central signaling complexes that are involved in various aspects of sclerotia development and infection.In this study,the putative downstream transcription factor of MAPK pathway,SsSte12,was analyzed in S.sclerotiorum.Silencing SsSte12 in S.sclerotiorum resulted in phenotypes of delayed vegetative growth,reduced size of sclerotia,and fewer appressoria formation.Consequently,the SsSte12 RNAi mutants showed attenuated pathogenicity on the host plants due to the defect compound appressorium.Yeast two-hybrid（Y2H） and bimolecular fluorescence complementation（BiFC） assays demonstrated that the SsSte12 interacts with SsMcml.However,the SsMcm1 expression is independent of the regulation of SsSte12 as revealed by qRT-PCR analysis in SsSte12 RNAi mutants.Together with high accumulation of SsSte12 transcripts in the early development of S.sclerotiorum.Our results demonstrated that SsSte12 function was essential in the vegetative mycelial growth,sclerotia development,appressoria formation and penetration-dependent pathogenicity.Moreover,the SsSte12-SsMcm1 interaction might play a critical role in the regulation of the genes encoding these traits in S.sclerotiorum.

关键词： SsSte12 Sclerotia Appressoria Pathogenicity SsMCM1

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Radiation Retinopathy Associated with Central Retinal Vein Occlusion

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眼科学报 2007年第2期23卷 126-128页

作者： Yan liu fengwen State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center Sun Yat-sen UniversityGuangzhou 510060 China

Purpose: To report a case of radiation retinopathy associated with central retinal vein occlusion. Methods: The clinical features and fundus fluorescein angiography of this case were analyzed. Results: The patient had been treated with radiotherapy for her nasopharyngeal carcinoma, and presented with sudden visual loss in the left eye. The funduscopic examination and fluorescein angiography showed the features of radiation retinopathy in both eyes, and central retinal vein occlusion in the left eye. Conclusions: Radiation retinopathy can be associated with central retinal vein occlusion in the same eye, and it seems that the endothelial cell loss caused by radiation retinopathy may lead to retinal vein occlusion.

关键词：辐射性视网膜病变视网膜中央静脉阻塞合并症症状诊断治疗

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碳纳米管/氮化硼水性涂料的制备与性能研究

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化工新型材料 2016年第12期44卷 134-136页

作者：刘丰文张浩楼平赵定义甘露国网浙江省电力公司湖州供电公司湖州313000 武汉科迪奥电力科技有限公司武汉430000

通过物理改性的方法提高碳纳米管的相容性,制备碳纳米管的水性分散液,将氮化硼粉体与碳纳米管分散液以及氟碳树脂乳液均匀混合,并通过砂磨机在高剪切力的作用下制得碳纳米管/氮化硼辐射散热涂料。通过对涂料的热导率、散热效果、附着力... 详细信息

通过物理改性的方法提高碳纳米管的相容性,制备碳纳米管的水性分散液,将氮化硼粉体与碳纳米管分散液以及氟碳树脂乳液均匀混合,并通过砂磨机在高剪切力的作用下制得碳纳米管/氮化硼辐射散热涂料。通过对涂料的热导率、散热效果、附着力以及微观结构的检测。结果证明:涂料具有较好的散热、降温和附着力较优性能。在氮化硼用量为14%时,涂料热导率达到7.0W/(m·K),涂料的降温幅度为25.0%,涂料附着力等级为2级。

关键词：碳纳米管氮化硼氟碳树脂辐射散热涂料

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以高水平赛事推动职业教育高质量发展——基于2022年全国职业院校技能大赛的分析

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中国职业技术教育 2024年第8期 18-28页

作者：曾天山房风文陈宏辉刘晓辉教育部职业教育发展中心山东交通职业学院

全国职业院校技能大赛历经14届的发展,在持续推动职业教育彰显类型定位、引领职业教育教学改革、培养高素质技术技能人才中发挥着越来越重要的作用。2022年在面对新冠肺炎疫情全年多点散发的严峻形势下顺利圆满举办,全面分析2022年大赛... 详细信息

全国职业院校技能大赛历经14届的发展,在持续推动职业教育彰显类型定位、引领职业教育教学改革、培养高素质技术技能人才中发挥着越来越重要的作用。2022年在面对新冠肺炎疫情全年多点散发的严峻形势下顺利圆满举办,全面分析2022年大赛办赛特点、亮点等,提出大赛创新发展的理念和举措,推动大赛持续为服务职业教育高质量发展,发挥更大更有力的作用。

关键词：全国职业院校技能大赛职业教育高质量发展

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