检索结果-南通市图书馆

Spatial patterns of urban land use growth in Beijing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of geographical Sciences 2002年第3期12卷 266-274页

作者： LIU Shenghe, Sylvia Prielei, LI Xiubin(1. Inst. of geographic Sciences and natural {2. {3., CAS, Beijing 100101, China 2. International institute for Applied System Analysis, A-2.3}1 Laxenburg, Austria) Inst. of geographic Sciences and natural {2. {3.. CAS 北京 100101 International institute for Applied System Analysis A-2361 Laxenburg 奥地利

By using digitized land use maps of Beijing in 1982. 1992.and 1997 and employing GIS spatial analysis techniques, this paper conducts an empirical study on the spatial differentiation and spatial patterns of urban land use growth in Beijing in the period of 1982.1997. It is observed that urban land use growth in Beijing went beyond the control of urban planning, in terms of the extraordinary high growth rate and undesired spatial pattern. The rate of urban expansion after 1982. which was predominated by growth of industrial land, was extraordinary high compared to its historical period. While its growth centers have been actively shifting toward the northern part, rather than toward the southern and eastern parts as designated by the latest General Plan (1991–2.10) of Beijing, its spatial pattern of urban land use growth in general was in distinct concentric sprawl, which seriously violated the General Plan of Beijing.

关键词： urban land use spatial differentiation growth pattern GIS Beijing

IMPACTS OF FLOOD EVENTS IN COARSE SEDIMENT-PRODUCING AREAS ON CHANNEL SILTATION AND FLUVIAL PROCESS OF THE LOWER YELLOW RIVER

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment research 2007年第2期22卷 142-149页

作者： Ou-yang ZHANG1, Xiufu FENG2.and Jiong-xin XU3. Bureau of Hydrology, Changjiang Water {2. Commission, Hubei, Wuhan 43.010, China2.Chengdu University of technology, Sichuan, Chengdu 610059, China3.2. of {3. Sciences and natural {2. research, CAS, Beijing 100101, China Changjiang Water resources Commiss Bureau Hydrol Wuhan 4310010 Peoples R China Chengdu Univ Technol Chengdu 610059 Peoples R China Chinese Acad Sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China

The method of multiple regression is used to analyze the influences of flood events from the coarse sediment producing areas on the channel siltation and fluvial process of the lower Yellow River based on the flood events from 1950 to 1985. The results showed that the flood events from the coarse sediment producing areas carry larger amounts of sediment load and coarser particle sizes than from other source areas, which increases deposition in the lower river channel. And there exist good correlations between channel siltation of the lower reaches of the Yellow River and the coming water and sediment of flood events from the coarse sediment producing areas. Through these correlations, the amounts of sediment deposition in the lower river channel could be roughly estimated based on the runoff and sediment load of flood events from the coarse sediment producing areas. The sediment deposition caused the fluvial process. There exists a complex response of channel form change to the coming water and sediment load of flood events from the coarse sediment producing areas. When the sediment concentration is smaller than 2.0kg/m3. the ratio between wide-depth ratio after flood and wide-depth ratio before flood((B/h)a / (B/h)b) will increase with the increase of the maximum sediment concentration; when the sediment concentration is near 2.0kg/m3. (B/h)a / (B/h)b reaches the maximum value; and when the sediment concentration reaches the limits of hyperconcentrated flow, (B/h)a / (B/h)b will decrease with the increase of the maximum sediment concentration. Generally, flood events from the coarse sediment producing areas made channel form of the lower Yellow River deeper and narrower, but a large amount of sediment deposition simultaneously occurs. So, the impacts of flood events from the coarse sediment producing areas on the channel of the lower Yellow River are lessened.

关键词： Channel siltation Fluvial process Coarse sediment-producing areas Flood events Yellow River basin

Seasonal compensation implied no weakening of the land carbon sink in the Northern Hemisphere under the 2.15/2.16 El Niño

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第1期67卷 281-294页

作者： Fangzhong SHI Xiuchen WU xiaoyan LI Philippe CIAIS Hongyan LIU Chao YUE Yuting yang Shulei ZHANG Shushi PENG Yi YIN Benjamin POULTER Deliang CHEN State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Faculty of geographical Science Beijing Normal UniversityBeijing 100875China Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation Qinghai Normal UniversityXining 810016China research and Development Center for Watershed Environmental Eco-Engineering Beijing Normal University(Zhuhai)Zhuhai 519085China Laboratoire des Sciences du Climat et de l’Environnement(LSCE) CEA-CNRS-UVSQUMR821291191Gif-sur-YvetteFrance College of Urban and Environmental Science MOE Laboratory for Earth Surface ProcessesPeking UniversityBeijing 100871China State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) School of Atmospheric SciencesSun Yat-sen UniversityGuangzhou 510275China California institute of Technology PasadenaCA 91125USA Biospheric Sciences Laboratory NASA Goddard Space Flight CenterGreenbeltMaryland 20771USA Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg SE-40530Sweden

The recurrent extreme El Niño events are commonly linked to reduced vegetation growth and the land carbon sink over many but discrete regions of the Northern Hemisphere(NH).However,we reported here a pervasive and continuous vegetation greening and no weakened land carbon sink in the maturation phase of the 2.15/2.16 El Niño event over the NH(mainly in the extra-tropics),based on multiple evidences from remote sensing observations,global ecosystem model simulations and atmospheric CO_(2.*** discovered a significant compensation effect of the enhanced vegetation growth in spring on subsequent summer/autumn vegetation growth that sustained vegetation greening and led to a slight increase in the land carbon sink over the spring and summer of 2.15(average increases of 2.0}3.%and 0.63.in net ecosystem exchange from two independent datasets relative to a 5-years average before the El Niño event,respectively)and spring of 2.16(6.82.),especially in the extra-tropics of the NH,where the water supply during the pre-growing-season(November of the previous year to March of the current year)had a positive *** seasonal compensation effect was much stronger than that in 1997 and 1998 and significantly alleviated the adverse impacts of the 2.15/2.16 El Niño event on vegetation growth during its maturation *** legacy effect of water supply during the pre-growing-season on subsequent vegetation growth lasted up to approximately six *** findings highlight the role of seasonal compensation effects on mediating the land carbon sink in response to episodic extreme El Niño events.

关键词： El Niño Seasonal compensation effect Vegetation greening Land carbon sink Net ecosystem exchange Legacy effect

ANALYSIS OF DRIVING FORCES ON THE CHANGE OF HISTORICAL FARMLAND USE IN SHANDONG PROVINCE DURING THE QING DYNASTY (1644-1911)

在线全文

学校读者我要写书评

暂无评论

Chinese geographical Science 2003年第3期13卷 207-215页

作者： ZHANG Xue-in, GE Quan-heng, ZHENG Jing-un(institute of geographic Sciences and {2. {3. research, Chinese academy of Sciences, Beijing 100101, P. R. China) institute of geographic Sciences and {2. {3. research Chinese Academy of Sciences Beijing P. R. China

How land-cover has been changed by human use over the last 3.0 years is oneof the five overarching questions guiding the Land-use/Cover Change (LUCC) Science/research *** has variety of historical documents providing unique data superiority. So the characteristicsof farmland area in Shandong Province during the Qing Dynasty (1644-1911) are summarized firstly: 1)the rising trend of farmland area was striking; 2. farmland area had remarkable fluctuation; 3.farmland area per capita decreased dramatically; 4) wasteland reclamation index increased ***, the driving forces of farmland area change are analyzed. It is concluded that natural andhuman factors are jointly influential. Among the driving forces, human dimensions are the mainfactors of farmland area change, which direct the general tendency of the changes mentioned *** the natural factors influence the stability of farmland area as well. Variation of the naturalfactors would act as the major contributory factor to farmland area change during years or periodsof abrupt climatic changes, or during the intensive occurring periods of natural hazards. Besides,the passive aspects of human factors, such as war chaos also influenced the fluctuation of thefarmland area. This research indicates that it is feasible to study the land-use/cover change byChinese historical literatures, which has huge potential to provide a comprehensive picture of thegrowing dominance of human land-use and land-cover patterns that can be used in many global changeresearch projects.

关键词： farmland driving forces shandong province qing dynasty

Optimal land use allocation of urban fringe in Guangzhou

在线全文

学校读者我要写书评

暂无评论

Journal of geographical Sciences 2012年第1期22卷 179-191页

作者： GONG Jianzhou LIU Yansui CHEN Wenli institute of geographic Sciences and {2. {3. research CAS School of geographical Sciences Guangzhou University Guangdong Party institute of CCP Guangdong Administration institute

In response to the strong drive for social and economic development, local governments have implemented urban master plans, providing measures and timeframes to address the continuous demand for land and to alleviate urban problems. In this paper, a multi-objective model was constructed to discuss the problem, including economic benefits and ecological effectiveness, in terms of land use optimization. A genetic algorithm was then adopted to solve the model, and a performance evaluation and sensitivity analysis were conducted using Pareto optimality. Results showed that a set of tradeoffs could be acquired by the allocation of land use. In addition, the Pareto solutions proved the model to be efficient; for example, a limit of 13.500 ha of urban area conformed to plan recommendations. The reduction in crop land, orchard land, grassland, and unused land provided further efficiencies. These results implied that further potential regional land resources remain and that the urban master plan is able to support sustainable local development in the years to come, as well as verified that it is feasible to use land use allocation multi-objective modeling and genetic algorithms.

关键词： optimal allocation land use multi-objective modeling genetic algorithms fringe area

In-situ UV-Vis Spectroscopy of Trisulfur Radicals in Lithium-Sulfur Batteries

在线全文

学校读者我要写书评

暂无评论

Chemical research in Chinese Universities 2024年第2期40卷 279-286页

作者： DOU Renju WANG Qin REN xiaoyan LU Lehui School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026P.R.China State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022P.R.China

Here we employ in-situ UV-Vis spectroscopy to monitor the sulfur redox reaction with oxygen-containing molecules as an additive,for example,biphenyl-4,4′-dicarboxylic acid(BDC).Furthermore,Raman spectrum,electron paramagnetic resonance(EPR),and electrospray ionization-mass spectrometry(ESI-MS)measurements reveal that the formation of BDC-S_(3.•^(‒)complexes can establish the long-term stability of polysulfide radicals,change the kinetics of sulfur redox reaction,and then generate decent capacity retention and rate *** to the density functional theory(DFT)analysis,S_(3.•^(‒)radicals are the underlying product of S_(6)^(2.)cleavage,owing to the decreased chemical energy and the increased stability of S_(3.•^(‒)radicals through Lewis acid-base *** assembled Li-S batteries with BDC additive deliver a high reversible capacity of 42. mA·h·g^(−1)over 2.0 cycles with over 98%Coulombic efficiency,under the current density of 0.2.C.

关键词： Radical Polysulfide In-situ UV-Vis Spectroscopy Electrolyte additive Lithium-sulfur battery

Polystyrene nanoplastics induce glycolipid metabolism disorder via NF-κB and MAPK signaling pathway in mice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第3期137卷 553-566页

作者： Xingpei Fan xiaoyan Li Jiaxin Li Yuxia Zhang Xiangjuan Wei Hailong Hu Boya Zhang Haining Du Meimei Zhao Ruijiao Zhu Daqian yang Yuri Oh Ning Gu School of Life Science and Technology Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150006China Department of Medicine Renal Electrolyte and Hypertension DivisionDepartment of GeneticsPerelman School of MedicineUniversity of PennsylvaniaPhiladelphia 19104USA Faculty of Education Wakayama UniversityWakayama 640-8441Japan

Nanoplastics-induced developmental and reproductive toxicity,neurotoxicity and immunotoxicity are a focus of widespread ***,the effects of nanoplastics(NPs)on glycolipid metabolism and the precise underlying mechanisms are unclear at ***,we showed that oral administration of polystyrene nanoparticles(PS-NPs)disrupts glycolipid metabolism,with reactive oxygen species(ROS)identified as a potential key signaling *** PS-NPs treatment,excessive production of ROS induced the infammatory response and activated the antioxidant pathway through nuclear factor-erythroid factor 2.related factor *** activation of nuclear factor-κB(NFκB)signaling pathway induced the phosphorylation of the mitogen-activated protein kinases(MAPK)signaling pathway,which induced the activation of extracellular regulated kinases(ERK)and *** activation of the MAPK signaling proteins induced high continued phosphorylation of insulin receptor substrate-1,in turn,leading to decreased protein kinase B(Akt)activity,which weakened the sensitivity of liver cells to insulin signals and induced insulin *** parallel,phosphorylation of Akt led to loss of control of Fo XO1,a key gene of gluconeogenesis,activating transcription of glucose-6-phosphatase(G6PC)and phosphoenolpyruvate carboxykinase(PEPCK)in a manner dependent on PGC1α.Moreover,the activated ERK promoted lipid accumulation through ERK-PPARγ***,sterol regulatory element-binding protein-1 and levels of its downstream lipogenic enzymes,ACC-1,were *** treatment with the antioxidant resveratrol,PS-NPs-induced glucose and lipid metabolic disorders were improved by inhibiting ROS-induced activation of NFκB and MAPK signaling pathway in *** on above,PS-NPs exposure disrupts glycolipid metabolism in mice,with ROS identified as a potential key signaling molecule.

关键词： Nanoplastics Resveratrol Hyperglycemia Lipid metabolism Infammatory response Reactive oxygen species(ROS)

research on Data Tampering Prevention Method for ATC Network Based on Zero Trust

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第3期78卷 4363-4377页

作者： xiaoyan Zhu Ruchun Jia Tingrui Zhang Song Yao School of Computer Science Hefei University of TechnologyHefei230000China College of Computer Science Sichuan UniversityChengdu610065China Sichuan University-Pittsburgh institute Sichuan UniversityChengdu610065China School of Information and Business Management Chengdu Neusoft UniversityChengdu610065China

The traditional air traffic control information sharing data has weak security characteristics of personal privacy data and poor effect,which is easy to leads to the problem that the data is *** from the application of the ATC(automatic train control)network,this paper focuses on the zero trust and zero trust access strategy and the tamper-proof method of information-sharing network *** the improvement of ATC’s zero trust physical layer authentication and network data distributed feature differentiation calculation,this paper reconstructs the personal privacy scope authentication structure and designs a tamper-proof method of ATC’s information sharing on the *** the single management authority to the unified management of data units,the systematic algorithm improvement of shared network data tamper prevention method is realized,and RDTP(Reliable Data Transfer Protocol)is selected in the network data of information sharing resources to realize the effectiveness of tamper prevention of air traffic control data during *** results show that this method can reasonably avoid the tampering of information sharing on the Internet,maintain the security factors of air traffic control information sharing on the Internet,and the Central Processing Unit(CPU)utilization rate is only 4.64%,which effectively increases the performance of air traffic control data comprehensive security protection system.

关键词： Zero trust access policy air traffic information sharing network privacy data tam-per-proof certification features

Predicting Bioaccumulation of Nanomaterials:Modeling Approaches with Challenges

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Environment & Health 2024年第4期2卷 189-201页

作者： Hang Zeng Zhuoyan Lv xiaoyan Sun yang Tong Wei Wu Shipeng Dong Liang Mao State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentChemistry and Biomedicine Innovation CenterNanjing UniversityNanjing 210023China Nanjing Qixia District Hospital Nanjing 210023China High Tech research and Development Center Ministry of Science and TechnologyBeijing 100044China

Understanding the bioaccumulation of nanomaterials(NMs)by organisms is essential in evaluating their potential ***,the experimental determination of bioaccumulation is substantially challenging,which spawned the development of prediction approaches via establishing models for various *** modeling approaches,such as the biotic ligand model(BLM),partition coefficients,accumulation factor models,and quantitative structure−activity relationship(QSAR)models,were initially used in the application of NMs,aiming to provide a reliable quantitative dose in a resource-saving *** methods,which are based on the uptake patterns of substances,probably lead to deviated results due to the different uptake behaviors of *** this study,currently developed models to evaluate the bioaccumulation of NMs are critically reviewed,with their feasibilities and limitations being *** addition,the recently developed machine learning amended models have taken great efforts in realizing biological behaviors of NMs in organisms by providing in silico *** this data-driven approach has limitations in mechanism exploration,it may give different insights into the bioaccumulation model establishment and critical feature identification.

关键词： Modeling Forecast Bioaccumulation Nanomaterials Machine learning