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Vegetation types and climate conditions reflected by the modern phytolith assemblages in the subalpine Dalaoling Forest Reserve, central China

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Frontiers of Earth Science 2015年第2期9卷 268-275页

作者： Djakanibe Desire TRAORE Yansheng GU Humei LIU Ceven SHEMSANGA jiwen ge State Key Laboratory of Biogeology and Environmental geology China University of Geosciences Wuhan 430074 China Hubei Key Laboratory of Wetland Evolution & Eco-Restoration (WEER) China University of Geosciences Wuhan 430074 China

This research describes modern phytolith records and distributions from subalpine surface soils in the Dalaoling Forest Reserve, and reveals its implications for local climate conditions with respect to the altitude gradient. Well-preserved phytolith morpho-types, assem- blages, and climatic indices were used to study the relationship between local vegetation and climate condi- tions. The phytolith classification system is mainly based on the characteristics of detailed morpho-types described for anatomical terms, which are divided into seven groups： long cells, short cells, bulliform cells, hair cells, pterido- phyte type, broad-leaved type, and gymnosperm type. Phytoliths originating from the Poaceae are composed of Pooideae （rondel and trapeziform）, Panicoideae （bilobate, cross, and polylobate）, Chloridoideae （short/square sad- dle）, and Bambusoideae （oblong concave saddle）. Based on the altitudinal distribution of the phytolith assemblages and the indices of aridity （Iph）, climate （Ic）, and tree cover density （D/P）, five phytolith assemblage zones have revealed the five types of climatic conditions ranging from 1,169 m to 2,005 m in turn： warm-wet, warm-xeric to warm-mesic, warm- xeric to cool-mesic, cool-xeric, and cool-mesic to cool-xeric. The Bambusoideae, Panicoideae, and Chloridoideae are the dominant vegetation at the lower-middle of the mountains, while Pooideae is mainly distributed in the higher mountains. The close relationship between phytolith assembleages and changes of altitude gradient suggest that vegetation distribution patterns and plant ecology in the Dalaoling mountains are controlled by temperature and humidity conditions. Our results highlight the importance ofphytolith records as reliable ecoclimatic indicators for vegetation ecology in subtropical regions.

关键词： central China subalpine surface soil phytolithrecords vegetation and climate change

Methane Flux and Its Environmental Impact Factors in Dajiuhu Wetland of Shennongjia

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Wuhan University Journal of Natural Sciences 2019年第5期24卷 455-460页

作者： Ihab ALFADHEL ge jiwen SINAN Yongxi LIU Yaoyao School of Environmental Studies China University of Geosciences

Methane(CH4) flux was measured by using the Eddy covariance technique in the Dajiuhu Wetland of Shennongjia Forestry District, Hubei Province, China. The seasonal and daily variation of CH4 emissions was investigated, and the correlation of CH4 fluxes with the environmental impact factors were discussed to understand the activity of CH4 flux and the effects of environmental factors including air temperature, soil temperature, photosynthetic photon flux density(PPFD), and rainfall on a wetland ecosystem. The results indicated that CH4 flux was significantly correlated with air temperature and photosynthetic photon flux density(PPFD), which may be the primary driver of controlling peatland CH4 flux.

关键词： methane (CH4) flux Dajiuhu Wetlands eddy covariance growing season environmental factors

Constructal design of a rectangular parallel phase change microchannel in a three-dimensional electronic device

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Science China(Technological Sciences) 2024年第5期67卷 1381-1390页

作者： ZHANG jiwen FENG HuiJun CHEN Lingen ge YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan430205China College of Power Engineering Naval University of EngineeringWuhan430033China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan430205China

Based on constructal theory,a rectangular parallel phase change microchannel model in a three-dimensional electronic device(TDED)is established with R134a as the cooling *** on the minimization of a complex function(CF)composed of linear weighting sum of maximum temperature difference and pumping power consumption,constructal design of the TDED is conducted first;and then,maximum temperature difference and pumping power consumption are minimized by non-dominated sorting genetic algorithm-II *** results reveal that there exist an optimal mass flow rate(0.0012 kg/s)and a quadratic optimal aspect ratio(AR)(0.39)of the microchannel which lead to quadratic minimum CF(0.817).Compared with the original value,the CF after optimization is reduced by 18.34%.Reducing the inlet temperature of cooling fluid and microchannel number appropriately can help to enhance the overall performance of *** using the artificial neural network and genetic algorithms in the toolboxes of Matlab software,the optimal AR gained in the Pareto solution set is located between 0.2–*** smallest deviation index among three discussed strategies is 0.346,and the corresponding optimal AR is 0.413,which is selected as the optimal design strategy of the microchannel in the TDED under multiple *** findings in this study can serve as theoretical guides for thermal designs of electronic devices.

关键词： constructal theory parallel microchannel evaporation phase change three-dimensional electronic device multi-objective optimization artificial neural network

夹芯复合材料在轨道交通领域的应用及研究进展

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高科技纤维与应用 2024年第1期49卷 77-84页

作者：曹亚周陈旭葛继文夏元平崔健中车青岛四方机车车辆股份有限公司山东青岛266000

夹芯复合材料,以其优异的力学性能和减重效果,在轨道交通领域得到了广泛的应用。本文介绍了三类常用的夹芯复合材料,列举了其在国内外轨道交通领域的典型应用,简述了夹芯复合材料的研究进展,建议后续可以在行业标准、计算机辅助设计、... 详细信息

夹芯复合材料,以其优异的力学性能和减重效果,在轨道交通领域得到了广泛的应用。本文介绍了三类常用的夹芯复合材料,列举了其在国内外轨道交通领域的典型应用,简述了夹芯复合材料的研究进展,建议后续可以在行业标准、计算机辅助设计、工艺改进和多功能化这几个方向做更深入的研究。

关键词：夹芯复合材料轨道交通轻量化多功能化

The Synergism between Methanogens and Methanotrophs and the Nature of their Contributions to the Seasonal Variation of Methane Fluxes in a Wetland:The Case of Dajiuhu Subalpine Peatland

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Advances in Atmospheric Sciences 2022年第8期39卷 1375-1385,I0017-I0023页

作者： Luwen WANG jiwen ge Liang FENG Yaoyao LIU Yu LI Jiumei WANG Xiang XIAO Zhiqi ZHANG Laboratory of Basin Hydrology and Wetland Eco-Restoration China University of GeosciencesWuhan 430074China Hubei Key Laboratory of Wetland Evolution and Ecological Restoration China University of GeosciencesWuhan 430074China Institution of Ecology and Environmental Sciences China University of GeosciencesWuhan 430074China Shennongjia National Park Administration Bureau Shennongjia Forestry District 442417China

Wetland ecosystems are the most important natural methane(CH_(4))sources,whose fluxes periodically ***(methane producers)and methanotrophs(methane consumers)are considered key factors affecting CH_(4)fluxes in ***,the symbiotic relationship between methanogens and methanotrophs remains *** help close this research gap,we collected and analyzed samples from four soil depths in the Dajiuhu subalpine peatland in January,April,July,and October 2019 and acquired seasonal methane flux data from an eddy covariance(EC)system,and investigated relationships.A phylogenetic molecular ecological networks(pMENs)analysis was used to identify keystone species and the seasonal variations of the co-occurrence patterns of methanogenic and methanotrophic *** results indicate that the seasonal variations of the interactions between methanogenic and methanotrophic communities contributed to CH_(4)emissions in *** keystone species discerned by the network analysis also showed their importance in mediating CH_(4)***(CH_(4))emissions in wetlands were lowest in spring;during this period,the most complex interactions between microbes were observed,with intense competition among methanogens while methanotrophs demonstrated better *** patterns manifested themselves in summer when the highest CH_(4)flux was *** formicica was negatively correlated with CH_(4)fluxes and occupied the largest ecological niches in the spring *** contrast,both Methanocella arvoryzae and Methylocystaceae demonstrated positive correlations with CH_(4)fluxes and were better adapted to the microbial community in the *** addition,soil temperature and nitrogen were regarded as significant environmental factors to CH_(4)*** study was successful in explaining the seasonal patterns and microbial driving mechanisms of CH_(4)emissions in wetlands.

关键词： CH_(4)fluxes wetland methanogens methanotrophs molecular ecological network

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复合材料拉挤成型技术及其运用分析

模具制造 2024年第5期24卷 172-176页

作者：葛继文夏元平曹亚周陈旭程正珲中车青岛四方机车车辆股份有限公司山东青岛266111 南京诺尔泰复合材料设备制造有限公司江苏南京211506

复合材料拉挤成型是一种先进的成型技术,可实现大型复杂结构件的快速制造。首先概述了该技术的基本原理、工艺过程和设备;其次重点分析了模具设计、挤出温度、挤出速度以及配方设计等关键工艺参数及其影响因素;最后着重探讨了拉挤成型... 详细信息

复合材料拉挤成型是一种先进的成型技术,可实现大型复杂结构件的快速制造。首先概述了该技术的基本原理、工艺过程和设备;其次重点分析了模具设计、挤出温度、挤出速度以及配方设计等关键工艺参数及其影响因素;最后着重探讨了拉挤成型技术在汽车车身零部件、内饰件和结构件制造中的具体应用实例,证明该技术可以实现高性能汽车部件的轻量化生产。研究表明,复合材料拉挤成型技术在推动汽车轻量化和功能一体化方面具有重要应用前景和潜力。

关键词：复合材料拉挤成型汽车轻量化

维普期刊数据库博看期刊

Water Losses in Arid and Semi-Arid Zone:Evaporation, Evapotranspiration and Seepage

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Journal of Mountain Science 2012年第2期9卷 256-261页

作者： MUPENZI Jean de la Paix LI Lanhai ge jiwen NGAMIJE Jean ACHAL Verenyam HABIYAREMYE Gabriel HABUMUGISHA Jean de Dieu State Key laboratory of Desert and Oasis Ecology Xinfiang Institute of Ecologg and Geography Chinese Academy of Sciences 818 Beijing road south Urumqi Xinjiang 830011 China China University ofgeosciences （Wuhan） 388 Lumo Road Wuhan 430074 Hubei China Independent Institute of Lay Adventists ofKigali （INILAK） P O Box 6392 Kigali-Rwanda Institut Polytechnique de Byumba （IPB） PO Box 25 Byumba Rwanda

The primary purpose of this study was to assess water losses by evapotranspiration, evaporation and seepage in arid ***, evaporation and seepage are the main causes of water *** modeling water losses,a combination of genetic Programming(GP),Penman-Monteith(PM) and Penman combination model for measurement of evapotranspiration,evaporation and seepage has been *** results were found to be varying depending on how the evaporation and seepage phenomena are *** results show that that there is an improvement in reducing evapotranspiration,evaporation and seepage losses in arid and semi-arid region.

关键词： Arid zone Evaporation Evapotranspiration Seepage Water losses China

复合材料先进拉挤工艺优化与直热模具温度场研究

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粘接 2024年第6期51卷 73-75,79页

作者：陈旭崔健曹亚周夏元平程正珲葛继文中车青岛四方机车车辆股份有限公司山东青岛266000 南京诺尔泰复合材料设备制造有限公司江苏南京211506

为了研究复合材料下先进拉挤工艺固化反应与直热模具温度场。通过有限元分析完成复合材料的建模和模块单元的网格划分,在有限元模型下完成对复合材料的拉挤工艺固化反应研究,并对复合材料直热模具温度场的数值模拟。研究结果表明,复合... 详细信息

为了研究复合材料下先进拉挤工艺固化反应与直热模具温度场。通过有限元分析完成复合材料的建模和模块单元的网格划分,在有限元模型下完成对复合材料的拉挤工艺固化反应研究,并对复合材料直热模具温度场的数值模拟。研究结果表明,复合材料温度场模拟中最大温差在400 mm处出现了最小值,温度方差在500 mm处出现了最小值,说明在此区域内分布的最均匀。复合材料下先进拉挤工艺固化反应与直热模具温度场的研究可以确定复合材料的温度分布特征。

关键词：复合材料直热模具温度场数值模拟

Present Utilization Analysis and Development Countermeasures on Biomass Energy in China

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Present Utilization Analysis and Development Countermeasures...