检索结果-南通市图书馆

Cropland redistribution to marginal lands undermines environmental sustainability

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第1期9卷 66-78页

作者： Wenhui Kuang Jiyuan Liu Hanqin Tian hao Shi Jinwei Dong changqing Song Xiaoyong Li Guoming Du Yali Hou Dengsheng Lu Wenfeng Chi Tao Pan Shuwen Zhang Rafiq Hamdi Zherui Yin Huimin Yan Changzhen Yan Shixin Wu Rendong Li Jiuchun Yang Yinyin Dou Wenbin Wu Liqiao Liang Bao Xiang Shiqi Yang Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences International Center for Climate and Global Change Research School of Forestry and Wildlife Sciences Auburn University Faculty of Geographical Science Beijing Normal University State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences School of Public Administration and Law Northeast Agricultural University School of Geographical Sciences Fujian Normal University School of Resources and Environmental Economics Inner Mongolia University of Finance and Economics School of Geography and Tourism Qufu Normal University Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Royal Meteorological Institute of Belgium Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Key Laboratory for Resources Use & Environmental Remediation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Hubei Province’s Key Laboratory for Environment & Disaster Monitoring and Evaluation Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Institute of Ecology Chinese Research Academy of Environmental Sciences College of Environment and Planning Henan University

Cropland redistribution to marginal land has been reported worldwide;however,the resulting impacts on environmental sustainability have not been investigated *** we investigated the environmental impacts of cropland redistribution in *** a result of urbanization-induced loss of high-quality croplands in south China(～8.5 t ha),croplands expanded to marginal lands in northeast(～4.5 t ha) and northwest China(～2.9 t ha) during 1990-2015 to pursue food ***,the reclamation in these low-yield and ecologically vulnerable zones considerably undermined local environmental sustainability,for example increasing wind erosion(+3.47%),irrigation water consumption(+34.42%),fertilizer use(+20.02%) and decreasing natural habitats(-3.11%).Forecasts show that further reclamation in marginal lands per current policies would exacerbate environmental costs by *** future cropland security risk will be remarkably intensified because of the conflict between food production and environmental *** research suggests that globally emerging reclamation of marginal lands should be restricted and crop yield boost should be encouraged for both food security and environmental benefits.

关键词： cropland redistribution environmental sustainability marginal lands wind erosion irrigation water consumption

水性聚氨酯/丙烯酸酯基多维度导电银浆的制备及低温固化特性

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

高分子材料科学与工程 2023年第6期39卷 131-137页

作者：程有亮邱文珂方长青陈昊韦莹西安理工大学印刷包装与数字媒体学院陕西西安710048

采用醇热法制备了纳米银颗粒、纳米银线和微米银片,对其进行多维度配合作为复合导电填料,以水性聚氨酯/丙烯酸脂复合树脂(WPUA)为载体和黏结相,采用搅拌混合法制备了水性树脂基多维度低温固化导电银浆。利用透射电镜、扫描电镜、水接触... 详细信息

采用醇热法制备了纳米银颗粒、纳米银线和微米银片,对其进行多维度配合作为复合导电填料,以水性聚氨酯/丙烯酸脂复合树脂(WPUA)为载体和黏结相,采用搅拌混合法制备了水性树脂基多维度低温固化导电银浆。利用透射电镜、扫描电镜、水接触角测试和电阻测试,研究了不同固化温度对导电银浆成膜后的力学性能、导电性能及亲疏水特性的影响。结果表明,随着固化温度的上升,银浆漆膜的硬度、附着力及耐水性逐渐增加,WPUA基银浆漆膜的硬度在120℃时可达到3H等级,附着力在100℃可达到1等级,水接触角在140℃时可以达到93°;而WPUA银浆漆膜的电阻率随着固化温度的上升,呈现先增加后减小的趋势,在固化温度为160℃时的电阻率为0.19×10^(-3)Ω·cm。文中制备的多维度复合导电银浆在柔性电子印刷领域有着很好的应用前景。

关键词：银浆黏结相低温固化

Finite element model updating and validating of Runyang Suspension Bridge based on SHMS

在线全文

学校读者我要写书评

暂无评论

Journal of Southeast University(English Edition) 2005年第4期21卷 474-479页

作者：王浩李爱群缪长青东南大学土木工程学院南京210096

Based on the finite element （FE） program ANSYS, a three-dimensional model for the Runyang Suspension Bridge （RSB） is established. The structural natural frequency, vibration mode, stress and displacement response under various load cases are given. A new method of FE model updating is presented based on the physical meaning of sensitivity and the penalty function concept. In this method, the structural model is updated by modifying the parameters of design, and validated by structural natural vibration characteristics, stress response as well as displacement response. The design parameters used for updating are bounded according to measured static response and engineering judgment. The FE model of RSB is updated and validated by the measurements coming from the structural health monitoring system （SHMS）, and the FE baseline model reflecting the current state of RSB is achieved. Both the dynamic and static results show that the method is effective in updating the FE model of long span suspension bridges. The results obtained provide an important research basis for damage alarming and health monitoring of the RSB.

关键词： suspension bridge finite element model updating model validating baseline model structural health monitoring system (SHMS)

Reconciled estimation of Antarctic ice sheet mass balance and contribution to global sea level change from 1996 to 2021

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第11期67卷 3562-3578页

作者： Rongxing LI Guojun LI Gang HAI Huan XIE Yuan CHENG Wei CHEN Xiangbin CUI Minghu DING Chunchun GAO Tong hao changqing KE Chuanjin LI Jin LI Yan LIU Jiangjun RAN Jiawen REN Qiang SHEN Yunzhong SHEN Hongling SHI Songyun WANG Zemin WANG Jingang ZHAN Baojun ZHANG Min ZHONG Chunxia ZHOU Center for Spatial Information Science and Sustainable Development Applications Tongji UniversityShanghai 200092China College of Surveying and Geo-informatics Tongji UniversityShanghai 200092China Institute for the Conservation of Cultural Heritage School of Cultural Heritage and Information ManagementShanghai UniversityShanghai 200444China College of Resource Environment and Tourism Hubei University of Arts and ScienceXiangyang 441053China Polar Research Institute of China Shanghai 200136China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China College of Geodesy and Geomatics Shandong University of Science and TechnologyQingdao 266590China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China State Key Laboratory of Remote Sensing Science Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055China State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China Center for Space Research University of Texas at AustinAustin TX 78759USA Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China School of Geospatial Engineering and Science Sun Yat-sen UniversityZhuhai 519082China

The Antarctic Ice Sheet(AIS)has been losing ice mass and contributing to global sea level rise(GSLR).Given its mass that is enough to cause~58 m of GSLR,accurate estimation of mass balance trend is critical for AIS mass loss monitoring and sea level rise ***,we present an improved approach to reconciled solutions of mass balance in AIS and its regions from multiple contributing solutions using the input-out,altimetric,and gravimetric *** comparison to previous methods,such as IMBIE 2018,this approach utilizes an adaptive data aggregation window to handle the heterogeneity of the contributing solutions,including the number of solutions,temporal distributions,uncertainties,and estimation *** improved the regression-based method by using a two-step procedure that establishes ensembled solutions within each method(input-output,altimetry,or gravimetry)and then estimates the method-independent reconciled *** the first time,16contributing solutions from 8 Chinese institutions are used to estimate the reconciled mass balance of AIS and its regions from1996 to *** results show that AIS has lost a total ice mass of~3213±253 Gt during the period,an equivalent of~8.9±0.7 mm of *** is a sustained mass loss acceleration since 2006,from 88.1±3.6 Gt yr^(-1)during 1996–2005 to 130.7±8.4 Gt yr^(-1)during 2006–2013 and further to 157.0±9.0 Gt yr^(-1)during 2014–*** mass loss signal in the West Antarctica and Antarctic Peninsula is dominant and clearly presented in the reconciled estimation and contributing solutions,regardless of estimation methods used and fluctuation of surface mass *** and challenges remain in mass balance estimation in East *** reconciled estimation approach can be extended and applied for improved mass balance estimation in the Greenland Ice Sheet and mountain glacier regions.

关键词： Antarctic Ice Sheet Ice mass loss acceleration Sea level rise Reconciled estimation

Biomechanical change of lumbar unilateral graded facetectomy and strategies of its microsurgical reconstruction:report of 23 cases

在线全文

学校读者我要写书评

暂无评论

Journal of Medical Colleges of PLA(China) 2008年第2期23卷 98-105页

作者： Zhou Yue Luo Gang Chu Tongwei Wang Jian Li changqing Zheng Wenjie Zhang Zhengfeng hao Yong Zhang Chao Department of Orthopaedics Xinqiao Hospital Third Military Medical University Chongqing 400038 China

Objective： To evaluate the lumbar stability and the primary clinical results of unilateral facetectomy, transforaminal lumbar interbody fusion （TLIF） and unilateral pedicle screw fixation by X-Tube system. Methods： Five human lumbar cadaveric functional spine units（FSU） were obtained and graded facetectomy by 0, 1/4, 1/2, 3/4 and 4/4 were performed respectively on the left articular process of them. The stability of these 5 models was evaluated at flexion, extension, lateral bending and axial rotation. After a serial of biomechanical researches, 23 patients from June 2004 to March 2006 in our department underwent unilateral facetectomy, transforaminal lumbar interbody fusion （posterior lumbar interbody fusion） and unilateral pedicle screw instrumentation by X-Tube system. After general anaesthesia, with the guide of fluoroscopy and using X-Tube system, procedures of unilateral endoscopic facetectomy, spinal nerve root decompression, autologus spongy bone transplantation, one cage oblique insertion and unilateral pedicle screw instrumentation were performed. Results： There was no significant difference in flexion, extension, lateral bending and axial rotation of lumbar motion range after unilateral graded facetectomy. The stability of left/right axial direction was greatly affected when the range of graded facetectomy exceed 1/2. According to the Nakai criteria, for the 23 patients, the clinical result was excellent in 15 （65.2%）, good in 6 （26.1%） and fair in 2 （8.7%）. The fusion rate was 95.6% in excellent and good cases. Although partial absorption of bone grafts was observed in 1 case which might indicate a unsuccessful fusion, there was no loosing and replacement of instrument and no clinical symptoms occurred. Conclusion： The lumbar stability will be affected significantly when the range of graded facetectomy exceeds 1/2. Procedures of unilateral facetectomy, transforaminal lumbar interbody fusion and unilateral pedicle screw fixation is an optional strategy

关键词： Endoscope Lumbar disc herniation Transforaminal lumbar interbody fusion

基于Zigbee的自供电高压母线无线温度监测系统设计

在线全文

学校读者我要写书评

暂无评论

电测与仪表 2015年第7期52卷 101-105页

作者：王长清王昊河南师范大学物理与电子工程学院河南新乡453007

为保证变电站高压母线供电安全,设计了自供电的高压母线无线温度监测系统,由温度传感器采集温度,Zigbee模块传输数据,实现温度无线监测,供电方式采用基于TI公司的bq25504能量采集芯片采集太阳能为无线测温模块供电,保证系统长期正常工作... 详细信息

为保证变电站高压母线供电安全,设计了自供电的高压母线无线温度监测系统,由温度传感器采集温度,Zigbee模块传输数据,实现温度无线监测,供电方式采用基于TI公司的bq25504能量采集芯片采集太阳能为无线测温模块供电,保证系统长期正常工作,从而解决了无线温度监测方式电池供电周期短的问题。

关键词：无线测温 Zigbee 高压设备能量采集 bq25504

在线全文

学校读者我要写书评

暂无评论

对气井二项式系数B的新认识

天然气工业 2002年第6期22卷 84-86页

作者：郝玉鸿陈调胜中国石油长庆油田公司勘探开发研究院

在气井产能试井过程中 ,通常人们把井筒储集效应消失后的二项式系数B认为是恒定常数 ,但实践却证明 ,由此确定的二项式系数B误差较大。文章基于气井二项式产能方程通式 ,考虑探测半径及对应渗透率的变化 ,从理论上推导了二项式系数B的... 详细信息

在气井产能试井过程中 ,通常人们把井筒储集效应消失后的二项式系数B认为是恒定常数 ,但实践却证明 ,由此确定的二项式系数B误差较大。文章基于气井二项式产能方程通式 ,考虑探测半径及对应渗透率的变化 ,从理论上推导了二项式系数B的变化规律。完整、准确地说 ,二项式系数B受探测半径及对应渗透率的影响 ,只不过在井筒储集效应阶段系数B变化明显 ,当探测半径扩大到一定程度 (当然井筒储集效应已经消失 ) ,二项式系数B受探测半径及对应渗透率的影响越来越小 ,逐渐趋于一恒定常数。这对加深理解二项式系数B及产能试井合理设计、得到稳定可靠的产能方程和无阻流量起到了重要指导作用。

关键词：气井二项式系数B 产能试井

水源热泵与城市供水系统相结合的水、冷、暖三联产可行性研究

在线全文

学校读者我要写书评

暂无评论

铁道科学与工程学报 2013年第3期10卷 121-128页

作者：欧阳长青郝小礼李晓湘潭市规划建筑设计院湖南湘潭411100 湖南科技大学能源与安全工程学院湖南湘潭411201 湖南凌天科技有限公司湖南湘潭411201

为探讨将城市供水作为水源热泵系统的水源,实现建筑供水、供冷、供暖三联供的可行性,调查了城市供水与地表水水源热泵系统在水源取水口、水温、水质、水量要求上的一致性,并提出了水源热泵与城市供水系统相结合的系统形式。以日供水量... 详细信息

为探讨将城市供水作为水源热泵系统的水源,实现建筑供水、供冷、供暖三联供的可行性,调查了城市供水与地表水水源热泵系统在水源取水口、水温、水质、水量要求上的一致性,并提出了水源热泵与城市供水系统相结合的系统形式。以日供水量为20万t的城市供水厂为例,理论分析了系统在夏季和冬季的节能潜力,对系统可能存在的风险进行了探讨。研究结果表明:系统在夏季和冬季的一次能源节约率分别为40.8%和18.3%。通过将水源热泵与城市供水系统相结合,实现城市供水、供冷、供暖三联产,在夏热冬冷和夏热冬暖地区是可行的,具有较大的节能潜力。

关键词：水源热泵城市供水联产节能

在线全文

学校读者我要写书评

暂无评论

聚氯乙烯/插层水滑石的热稳定性和力学性能

硅酸盐学报 2013年第4期41卷 516-520页

作者：许家友周细濠叶常青杨俊郝勇广州大学化学化工学院广州510006 广东顺德金康业塑料公司广东顺德528300

马来酸和水滑石(MgAl-CO3LDHs)反应制备马来酸根插层水滑石(MgAl-maleate LDHs),X射线衍射和红外光谱分析表明马来酸根已插层水滑石层间。把插层有马来酸根的水滑石填充聚氯乙烯(PVC),研究马来酸根插层水滑石对PVC热稳定性和力学性能的... 详细信息

马来酸和水滑石(MgAl-CO3LDHs)反应制备马来酸根插层水滑石(MgAl-maleate LDHs),X射线衍射和红外光谱分析表明马来酸根已插层水滑石层间。把插层有马来酸根的水滑石填充聚氯乙烯(PVC),研究马来酸根插层水滑石对PVC热稳定性和力学性能的影响。结果表明:水滑石层间的马来酸根中的双键和PVC降解产生的C=C共轭双键发生Alder-delies加成反应,PVC的初期色泽得到改善,但PVC的长期热稳定性稍有降低;同时,插层改性后的水滑石改善了PVC和水滑石之间的相容性,提高了PVC的力学强度。

关键词：聚氯乙烯水滑石马来酸根热稳定性力学性能