检索结果-南通市图书馆

Deforestation in Latin America in the 2000s predominantly occurred outside of typical mature forests

The Innovation 2024年第3期5卷 88-98页

作者： Zhiyu Zhang Wenjian ni shaun Quegan Jingming Chen Peng Gong Luiz Carlos Estraviz Rodriguez Huadong Guo Jiancheng shi Liangyun Liu Zengyuan Li Yating He Qinhuo Liu Yosio shimabukuro Guoqing sun Key Laboratory of Remote sensing and Digital Earth Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of sciences Shijingshan DistrictBeijing 100049China Chinal of Mathematics and statistics University of SheffieldSheffield S37RHUK Department of Geography and Program in Planning University of TorontoTorontoON M5S 3G3Canada Department of Earth sciences and Department of Geography University of Hong KongHong KongChina Forest science Department Luiz de Queiroz College of AgricultureUniversity of São PauloAv.Pádua Dias11Piracicaba 13418-900Brazil National space science Center Chinese Academy of SciencesBeijing 100190China Institute of Forest Resource Information Techniques Chinese Academy of ForestryBeijing 100091China Research Institute of Forest Policy and Information Chinese Academy of ForestryBeijing 100091China Remote sensing Department National Institute for Space Research(INPE)Av.dos Astronautas 1758São Josédos Campos 12227-010Brazil Department of Geographical sciences University of MarylandCollege ParkMD 20742USA

The role of tropical forests in the global carbon budget remains controversial,as carbon emissions from deforestation are highly *** high uncertainty arises from the use of either fixed forest carbon stock density or maps generated from satellite-based optical reflectance with limited sensitivity to biomass to generate accurate estimates of emissions from *** space missions aiming to accurately map the carbon stock density rely on direct measurements of the spatial structures of forests using lidar and *** found that lost forests are special cases,and their spatial structures can be directly measured by combining archived data acquired before and after deforestation by space missions principally aimed at measuring ***,using biomass mapping,we obtained new estimates of carbon loss from deforestation ahead of forthcoming space ***,using a high-resolution map of forest loss and the synergy of radar and lidar to estimate the aboveground biomass density of forests,we found that deforestation in the 2000s in Latin America,one of the severely deforested regions,mainly occurred in forests with a significantly lower carbon stock density than typical mature forests.

关键词： forest Latin lidar

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geochemical elements in suspended particulate matter of Ensenada de La Paz Lagoon,Baja California Peninsula,Mexico:sources,distribution,mass balance and ecotoxicological risks

引用

Journal of Environmental sciences 2024年第2期136卷 422-436页

作者： sandra soledad Morales-García Pilar de Acacia Pérez-Escamilla suresh Babu sujitha Pichaimani Godwyn-Paulson Andrés Felipe Zuniga-Cabezas Muthuswamy Ponniah Jonathan Instituto Politécnico Nacional(IPN) Centro Mexicano para la Producción más Limpia(CMPL)Av.Acueducto s/nCol.Barrio la Laguna TicománDel Gustavo A.MaderoC.P.07340Ciudad de MéxicoMexico Instituto Politécnico Nacional(IPN) Escuela Superior de Ingeniería y Arquitectura(ESIA)Unidad Ticomán***án 600Delg.Gustavo A.MaderoC.P.07340Ciudad de México(CDMX)Mexico Instituto Politécnico Nacional(IPN) Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo(CIIEMAD)Calle 30 de Junio de 1520Barrio la Laguna TicománDel.Gustavo A.MaderoC.P.07340Ciudad de MéxicoMéxico

The present study aimed to evaluate multi-element concentrations(Al,As,Ca,Cd,Co,Cr,Cu,Fe,Mg,Mn,Mo,ni,Pb,sr)in suspended particulate material(sPM)collected from Ensenada de La Paz(ELP)lagoon,Baja California sur,Mexico in two different periods(september and May)to comprehend their origin,geochemical behavior,mass transfer and associated ecotoxicological *** 24 hr variation coefficient of volumetric sPM levels were found to be 51.7%in september and 40.5%in May,signifying the effects of oceanic *** calculated enrichment factor(EF)values for all the studied elements were of higher magnitude because of the high surface area and oxide nature of sPM,and in this study,Mo had the highest EF of 46.77 probably due to its origin from continental *** the ecotoxicological perspective,the integrated toxic risk index revealed low toxic risk to the benthic ***,the mean-ERM-Quotient calculated using the particulate concentrations of As,Cd,Cr,Cu,ni,Pb indicated 9%probability of toxicity to *** comprehensive geochemical and ecotoxicological assessment of particulate metal concentrations in the ELP lagoon signify low to moderate contamination.

关键词： suspended particulate material Heavy metals Risk assessment Mass transfer Ensenada de La Paz

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Impact of Robinia pseudoacacia stand conversion on soil properties and bacterial community composition in Mount Tai,China

引用

Forest Ecosystems 2021年第2期8卷 253-264页

作者： Kun Li Xu Han Ruiqiang ni Ge shi sergio de-Miguel Chuanrong Li Weixing shen Yikun Zhang Xingzhong Zhang Mountain Tai Forest Ecosystem Research station of state Forestry Administration/Key Laboratory of state Forestry Administration for silviculture of the Lower Yellow River Tai’an 271018ShandongChina Department of Crop and Forest sciences University of LleidaAv.Alcalde Rovira Roure 191E25198 LleidaSpain Joint Research Unit CTFC–AGROTECniO Av.Alcalde Rovira Roure 191E25198 LleidaSpain Mount Tai scenic spot Management Committee Tai’an 271000 ShandongChina

Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern *** of its.nitrogen-fixing ability,it can play a positive role in soil and forest *** clearcutting of planted stands,*** stands become coppice *** impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been wel *** study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice ***:nine 20 m×20 m plots were randomly selected in seedling and coppice *** bulk soil and rhizosphere soil were sampled in summer *** soil was sampled at 10 cm from the soil surface using a soil *** soil samples were col ected using a *** soil samples were transported to the laboratory for chemical analysis,and bacterial community composition and diversity was obtained through DNA extraction,16 s r RNA gene amplification and high-throughput ***:The results showed that,compared to seedling plantations,soil quality decreased significantly in coppice stands,but without affecting soil exchangeable Mg^(2+) and K^(+).Total carbon(C)and nitrogen(N)were lower in the rhizosphere than in bulk soil,whereas nutrient availability showed an opposite *** conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterialα-*** component analysis(PCA)showed that bacterial community composition was similar in both bulk and rhizosphere soils in second-generation coppice *** y,the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium,but reduced that of Actinobacteria,which may result in a decline of soil nutrient *** tests revealed that C,N,soil organic matte

关键词： Black locust coppice plantation Forest restoration Afforestation Microbial structure soil nutrient soil quality

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

流动青少年睡眠质量与父母教养方式

引用

中国临床心理学杂志 2017年第4期25卷 719-723页

作者：杨心玫邱晶青李虹倪士光清华大学医院管理研究院北京100084 清华大学深圳研究生院深圳518055 清华大学心理学系北京100084

目的:探索中国流动青少年睡眠质量和父母教养方式的现状,研究流动青少年睡眠质量与其父母教养方式的关系。方法:整群抽样选取广东省中山市3所中学1323名在校初中生进行问卷调查。问卷包括匹兹堡睡眠质量指数量表(Pittsburgh sleep Quali... 详细信息

目的:探索中国流动青少年睡眠质量和父母教养方式的现状,研究流动青少年睡眠质量与其父母教养方式的关系。方法:整群抽样选取广东省中山市3所中学1323名在校初中生进行问卷调查。问卷包括匹兹堡睡眠质量指数量表(Pittsburgh sleep Quality Index,PsQI)和简式父母教养方式问卷中文版(short-Egna Minnen av Barndoms Uppfostran-Chinese,s-EMBU-C)。结果:(1)流动青少年睡眠障碍检出率27.51%;(2)九年级学生在PsQI总分、入睡时间、睡眠时间、主观睡眠质量和日间功能障碍评分均高于七年级和八年级学生(P<0.05);(3)母亲拒绝、父亲情感温暖、母亲过度保护对子女睡眠质量影响最大。结论:流动青少年近三分之一有睡眠障碍,且个体差异较大。父母对子女的关怀越多,子女睡眠质量越好;父母对子女越严厉或冷漠,子女睡眠质量越差。

关键词：流动青少年睡眠质量父母教养方式回归分析

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Metal-enriched nanoparticles and black carbon:A perspective from the Brazil railway system air pollution

引用

Geoscience Frontiers 2021年第3期12卷 624-635页

作者： Bianca D.Lima Elba C.Teixeira James C.Hower Matheus s.Civeira Omar Ramírez Cheng-Xue Yang Marcos L.s.Oliveira Luis F.O.silva Postgraduate Program in Remote sensing and Meteorology Geosciences InstituteUniversidade Federal do Rio Grande do SulAv.Bento Gonçalves9500Porto AlegreRS 91501–970Brazil Research Department Fundação Estadual de Proteção Ambiental Henrique Luís RoesslerAv.Borges de Medeiros261Porto AlegreRS 90020–021Brazil Center for Applied Energy Research University of Kentucky2540 Research Park DriveLexingtonKY 40511USA Postgraduate Program in Mines Metallurgy and MaterialsUniversidade Federal do Rio Grande do SulAv.Bento Gonçalves9500Porto AlegreRS 91501–970Brazil Faculty of Engineering Environmental EngineeringUniversidad Militar Nueva GranadaKm 2 CajicáZipaquiráColombia Institute of Earth science China University of Geosciences(Beijing)29 Xueyuan RdHaidian DistrictChina Department of Civil and Environmental Universidad de la CostaCUCCalle 58#55-66BarranquillaAtlanticoColombia Universidad de Lima Departamento de Ingeniería civil y Arquitectura.Avenida Javier Prado Este 4600–Santiago de Surco 1503Peru

Having a better understanding of air pollutants in railway systems is crucial to ensure a clean public *** study measured,for the first time in Brazil,nanoparticles(NPs)and black carbon(BC)on two groundlevel platforms and inside trains of the Metropolitan Area of Porto Alegre(MAPA).An intense sampling campaign during thirteen consecutive months was carried out and the chemical composition of NPs was examined by advanced microscopy *** results showed that highest concentrations of the pollutants occur in colder seasons and influenced by variables such as frequency of the trains and passenger ***,internal and external sources of pollution at the stations were *** predominance of NPs enriched with metals that increase oxidative stress like Cd,Fe,Pb,Cr,Zn,ni,V,Hg,sn,and Ba both on the platforms and inside trains,including Fe-minerals as hematite and magnetite,represents a critical risk to the health of passengers and employees of the *** interdisciplinary and multi-analytical study aims to provide an improved understanding of reported adverse health effects induced by railway system aerosols.

关键词： Nanoparticles Potential hazardous elements Environmental chemistry Human health Railway environment Indoor air quality

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Releases of phosphate fertilizer industry in the surrounding environment:Investigation on heavy metals and polonium-210 in soil

引用

Journal of Environmental sciences 2010年第9期22卷 1387-1397页

作者： M.Aoun A.G.El samrani B.s.Lartiges V.Kazpard Z.saad Lebanese Atomic Energy Commission Lebanese University Faculty of SciencesPlatform for Research and Analysis in Environmental Sciences Nancy University-LEM-ENsG/INPL-CNRs-15 av.du Charmois

Distribution of Cu, Zn, Pb, Cr, ni, Mn concentrations and the activity of polonium-210 in the surrounding area of a phosphate fertilizer industry located on the eastern coast of the Mediterranean sea has been determined. nineteen sampling sites were distributed around the industrial zone on a surface area of about 100,000 m^2. Atomic absorption spectroscopy and Alpha spectroscopy were used to quantify the heavy elements and polonium-210, respectively. Investigation on a particle scale was conducted by TEM and sEM coupled to EDX and X-ray cartography to determine the nature of heavy elements carriers and their distribution. Heavy elements were mainly concentrated inside the particle size fraction 〈 50 μm. Their levels decreased with distance increasing from the industry. According to the reference soil, enrichment factors were about 10, 15, 32 and 100 times for Zn, Pb, Cu, and Cr, respectively inside the particle size fraction 〈 50 μm on the closest sites to the industry. The main contaminant sources were transport and storage of row materials and the free release of phosphogypsum waste. Heavy elements were entrapped inside agglomerates of sulfates, phosphates and iron oxihydroxides in a diffused shape. Polonium-210 with an enrichment factor of about 56, showed the same behavior of the spatial distribution of the trace elements.

关键词： heavy elements phosphogypsum fortilizer industry polonium-210 Alpha spectrometry

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Linking sedimentary provenance,climate and tectonics in the Neoproterozoic seridóBelt,Borborema Province(NE Brazil)

引用

Geoscience Frontiers 2023年第6期14卷 414-431页

作者： Carlos V.A.Ribeiro Marcos C.C.sales Armando L.s.de Oliveira Ricardo sallet Programa de Pós-graduação em Geologia Instituto de GeociênciasUniversidade de Brasília(UnB)CEP 70910-900 BrasíliaDFBrazil Programa de Pós-Graduação em Geociências Universidade Federal de PernambucoDepartamento de GeologiaCentro de Tecnologia e GeociênciasAv.da ArquiteturaCEP 50740-530 RecifePEBrazil Departamento de Geologia Universidade Federal do Rio Grande do NorteCEP 59078-970 NatalRNBrazil

The seridóBelt,at the extreme northeast of Brazil,is one of the several Neoproterozoic mobile belts related to the Brasiliano/Pan-African Orogeny in Western *** lithostratigraphy of the seridóBelt comprises basal quartzites and metaconglomerates(Equador Formation)overlain by hornblende-bearing paragneisses,calc-silicate rocks and marbles(Jucurutu Formation)and biotiteschists(seridóFormation).We investigated the sedimentary provenance of these rocks based on an integration of compiled whole-rock geochemistry,sm-Nd isotopes,U-Pb detrital zircon ages and a new set of whole-rock trace elements *** Formation quartzites have major and trace elements patterns that resemble cratonic sandstones,with a typical felsic provenance consistent with the isotopic composition of plutonic Archean to Paleoproterozoic basement *** proxies suggest that these rocks were deposited in fresh waters under anoxic conditions and moderate to intense weathering conditions(CIA=58–79).A shift in provenance led to an increase in intermediate-mafic sources during the deposition of the Jucurutu and seridó*** elements from rock types in these units are nearly identical,yet they differ on the contents of some high field-strength elements(e.g.,sc,V and ni),which are higher in the seridóFormation than average *** proxies show similar depositional environments,with brackish to marine conditions for the Jucurutu and seridóformations under anoxic to euxinic *** conditions are consistently lower in the Jucurutu Formation(CIA=58–66)in comparison with the seridóFormation(CIA=60–88).Compiled U-Pb data suggest maximum depositional ages of 633±11 Ma and 633±6 Ma for Jucurutu and seridóformations,respectively,suggesting deposition following the ca.645–635 Ma Marinoan *** compared the geochemistry of the seridóFormation schists with currently exposed basement rocks and showed a strong affinity with Neoproterozoic arc-related

关键词： Whole-rock geochemistry Marinoan Glaciation U-Pb detrital zircon Brasiliano Orogeny

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

一种基于层次路由推送的CCN移动性支持方案

引用

无线通信技术 2014年第1期23卷 42-46,51页

作者：刘义倪亚楠江苏大学计算机科学与通信工程学院镇江212013

随着互联网的快速发展,用户对内容信息的需求日趋明显,当前网络架构的设计已经不能满足时下服务的要求,因此,以信息为中心的未来网络的研究得以迅速发展。内容中心网络(CCN)是未来网络的研究热点之一,然而现阶段CCN的设计未深入考虑用... 详细信息

随着互联网的快速发展,用户对内容信息的需求日趋明显,当前网络架构的设计已经不能满足时下服务的要求,因此,以信息为中心的未来网络的研究得以迅速发展。内容中心网络(CCN)是未来网络的研究热点之一,然而现阶段CCN的设计未深入考虑用户移动性问题。本文针对CCN网络中的移动性管理问题,提出一种基于层次路由推送的解决方案。仿真结果表明,本文所提出的方法能有效降低用户获取内容的时间及网络中消息重传数目。

关键词： CCN 移动性层次路由推送

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于线性路径跟踪控制的换道避撞控制策略研究

引用

中国公路学报 2019年第6期32卷 86-95页

作者：刘志强王一凡吴雪刚张春雷倪捷江苏大学汽车与交通工程学院

为实现车辆自主避撞,改善道路交通安全状况,提出一种基于线性路径跟踪控制的换道避撞控制策略。为实时确定制动和换道时机,获取跟车状态下自车和前车车速、加速度、相对距离以及驾驶人制动反应时间计算制动安全距离和换道安全距离,并在... 详细信息

为实现车辆自主避撞,改善道路交通安全状况,提出一种基于线性路径跟踪控制的换道避撞控制策略。为实时确定制动和换道时机,获取跟车状态下自车和前车车速、加速度、相对距离以及驾驶人制动反应时间计算制动安全距离和换道安全距离,并在此基础上分别引入制动危险系数B和换道危险系数s评估制动与换道风险,使得车辆发生追尾碰撞的危险程度和主动干预阈值更直观。根据车辆期望横向加速度和期望横向位移的变化特性.采用5次多项式法规划符合驾驶人换道避撞特性的避撞路径。为保证换道避撞过程中驾驶人的安全舒适,采用最大横向加速度约束换道避撞轨迹。为实现对换道避撞路径的线性跟踪控制,保证车辆的操纵稳定性和横摆稳定性,基于车辆稳态动力学模型建立前馈控制,结合线性反馈控制消除换道路径的位置和横摆角偏差,修正参考路径实现直车道场景追尾避撞控制。仿真和实车交叉验证试验表明:根据车辆期望横向加速度和期望横向位移建立的符合驾驶人换道避撞特性的五次多项式换道路径与驾驶人实际换道避撞路径基本吻合,结合碰撞时间和车间时距的制动避撞控制策略能够在保证车辆行驶安全舒适性的同时有效避免车辆追尾碰撞.减少交通事故的发生。

关键词：汽车工程追尾避撞线性路径跟踪控制换道避撞危险评估横向加速度期望横向位移

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

镁铝二元水滑石焙烧产物对酸性紫90染料的吸附性能(英文)

引用

硅酸盐学报 2011年第2期39卷 371-376页

作者：薛继龙倪哲明郑立王巧巧胥倩阮璐璐祝海涛浙江工业大学化学工程与材料学院杭州310032

研究了镁铝比为3:1的二元水滑石(layered double hydroxides)焙烧产物(MgAl–LDO,layered double oxide)对弱酸性染料酸性紫90(C40H27CrN8Na2O10s2,av90)的吸附性能。X射线衍射和Fourier变换红外光谱的结果显示:由于水滑石的"结构记忆效应",在富水条件下,MgAl–LDO会吸附部分av90阴离子进入水滑石层间,从而恢复为层状结构的MgAl–LDHs。研究结果表明:MgAl–LDO对av90具有良好的去除效果,在298 K,pH=9.7条件下,MgAl–LDO对av90去除率高达99.7%,吸附容量为999.78 mg/g。MgAl–LDO对av90的吸附过程同时符合Langmuir和Freundlich等温吸附方程,并且是一个自发、放热的过程。动力学研究表明:该吸附动力学符合准二级动力学模型。吸附实验结果同时表明:MgAl–LDO吸附性能优于活性炭和二氧化硅等传统吸附剂,经三次回收利用的MgAl–LDO对av90仍具有良好的吸附性能。

关键词：镁铝二元水滑石焙烧产物吸附酸性紫热力学参数动力学

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：