检索结果-南通市图书馆

Acta Mechanica Solida Sinica 2020年第4期33卷 496-507页

作者： Zhichao Zhang shirong liu School of Civil Engineering and Science Yangzhou UniversityYangzhou 225127China

Thermoelastic damping(TED)is one of the main internal energy dissipation mechanisms in micro/*** evaluation of TED is important in the design of micro-electromechanical systems and nano-electromechanical *** this paper,a theoretical analysis on the TED in functionally graded material(FGM)micro-beam resonators is *** of motion and the heat conduction equation governing the thermodynamic coupling free vibration of non-homogenous micro-beams are established based on the Euler Bernoulli beam theory associated with the modified couple stress *** properties of the FGM micro-beam are assumed to change in the depth direction as power-law *** layer-wise homogenization method is used for solving the heat conduction *** using the mathematical similarity of eigenvalue problem between the FGM beam and the reference homogeneous one,the complex natural frequency including TED is expressed in terms of the natural frequency of the isothermal homogenous *** the presented numerical results,influences of various characteristic parameters,such as beam thickness,material gradient index,structure size,vibration mode and boundary conditions,on TED are examined in *** shows that TED decreases with the increases in the values of length scale parameters because the latter lead to the increase in structural stiffness.

关键词： Functionally graded material Size dependent Thermoelastic damping Micro-beam

Habitats shape root-associated fungal and bacterial communities of Minjiang fir saplings

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

Journal of Forestry Research 2023年第5期34卷 1491-1502页

作者： Maoping Li Ning Miao shirong liu International Centre for Bamboo and Rattan Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo&Rattan Science and TechnologyInstitute of Resources and EnvironmentBeijing 100102People’s Republic of China Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing 100091People’s Republic of China Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education College of Life SciencesSichuan UniversityChengdu 610065People’s Republic of China

Root-associated microbes play an essentialrole in mediating plant growth,health,and habitat ***,it is unknown which microbial taxa help develop host fitness and how habitats shape root-associated microbial assembly *** an endemic species of subalpine forests in western Sichuan,China,Minjiang fir(Abies fargesii ***)is dominant on cold-shaded northwestern slopes while absent on warm sunlit southwestern *** this study,fungal and bacterial communities were investigated in three spatial compartments(endosphere,rhizosphere,and bulk soil)associated with Minjiang fir saplings on a cold-shaded northwestern slope and a warm sunlit southwestern *** differentiated the microbial communities regardless of the spatial compartment and microbial *** aspect variations caused shifts in root-associated(rhizosphere and endosphere)microbial *** with the southwestern slope,the cold-shaded northwestern slope harbored a higher abundance of the growth-promoting bacteria Burkholderia and ectomycorrhizal fungi Cortinarius and *** slope aspect had stronger effects on fungal diversity than bacterial diversity,with higher fungal endemism and lower bacterial *** aspect variations were the dominant drivers of root-associated microbial communities,with lower contribution by soil properties and higher contribution by plant traits on the northwestern *** from this study could improve the understanding of plant habitat adaptability from the perspective of microbial community *** is suggested that forest management should consider root-associated microbiomes for enhancing species fitness and habitat adaptability.

关键词： Species fitness Root-associated microbes Microbial assembly patterns Habitat conditions

维普期刊数据库博看期刊

Natural forests exhibit higher organic carbon concentrations and recalcitrant carbon proportions in soil than plantations:a global data synthesis

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2024年第5期35卷 131-141页

作者： Xiuqing Nie Hui Wang Jian Wang shirong liu Ecology and Nature Conservation Institute Chinese Academy of ForestryKey Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationNo.2 DongxiaofuHaidian DistrictBeijing 100091People’s Republic of China

Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains *** synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution *** results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural ***-ever,SOC chemical compositions were appreciably more evenly distributed in *** on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under *** tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to *** factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical *** could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.

关键词： Global data synthesis Natural forest Plantations Soil organic carbon Soil organic carbon chemical composition

Demographic changes in China’s forests from 1998 to 2018

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2023年第1期10卷 82-91页

作者： Yanli Dong Evgenios Agathokleous shirong liu Zhen Yu Key Laboratory of Ecosystem Carbon Source and Sink China Meteorological Administration(ECSS-CMA)School of Applied MeteorologyNanjing University of Information Science and TechnologyNanjing210044China Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing100091China Research Center for Global Changes and Ecosystem Carbon Sequestration&Mitigation Nanjing University of Information Science&TechnologyNanjing210044China Institute of Ecology School of Applied MeteorologyNanjing University of Information Science&TechnologyNanjing210044China

Background: Tree demography is an essential indicator of various forest ecosystem services, and understanding its changes is critical for the sustainable management of forests. During the past four decades, China implemented unprecedented forest restoration projects, which altered tree demography by increasing the number of trees and introducing new species. However, it remains unclear how species composition has changed in China in response to the past forest restoration and demographical ***: We applied Forest Stability Index(FSI) and the relative change of FSI(%FSI) to describe the population dynamics of tree species and structure in China since 1998, using field-survey data collected from over 200,000plot-records from the 6th to 9th National Forest Inventories(NFIs).Results: The overall populations of both natural and planted forests have grown rapidly from 1998 to 2018, while the range of changes in the relative tree density was more variable for natural forests(ranging from-8.53% to42.46%) than for planted forests(ranging from-1.01% to 13.31%). The populations declined only in some of the tree species, including Betula platyphylla, Ulmus pumila, and Robinia pseudoacacia. In contrast, the populations of trees in the largest size-class either remained stable or ***: Tree density of China?s forests(both natural and planted forests) generally expanded and the overall populations increased in most size classes, with greater increases occurred in planted forests. In contrasting to the global decline trends of large diameter trees, here we found no apparent decline for trees in the largest size-class in China, highlighting China?s success in improving forest health and forest adaptations to climate change. We advocate for more studies to reveal the mechanisms of the changes in tree demography, which will help to improve forest ecosystem services such as the carbon sequestration capacity.

关键词： Tree demography Forest stability index(FSI) Relative change of FSI(%FSI) Relative density Tree species Tree size-class

Effects of nitrogen addition on clonal integration between mother and daughter ramets of Moso bamboo: a ^(13)C-CO_(2) pulse labeling study

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2022年第4期15卷 756-770页

作者： Wanlu Zhai Yi Wang Junwei Luan shirong liu Key Laboratory of Bamboo and Rattan Science and Technology State Forestry AdministrationInstitute of Resources and EnvironmentInternational Centre for Bamboo and RattanBeijing 100102China Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Research Institute of Forest EcologyEnvironment and ProtectionChinese Academy of ForestryBeijing 100091China

Resource sharing among connected ramets(*** integration)is one of the distinct traits of clonal *** integration confers Moso bamboo(Phyllostachys pubescens)a strong adaptability to different environmental *** the mechanisms of how clonal integration makes Moso bamboo has better performance are still poorly *** this study,acropetal and basipetal translocation of photosynthates between Moso bamboo ramets were analyzed separately to investigate how clonal fragments obtain higher benefits under heterogeneous N *** fragments of Moso bamboo consisting of two interconnected mother–daughter ramets were used,each of the ramets was subjected to either with or without N *** acropetal and basipetal translocation of ^(13)C-photosynthates was separated via single-ramet ^(13)C-CO_(2)-*** ramets translocated more ^(13)C-photosynthates to daughter ramets with N addition,and the translocation of ^(13)C-photosynthates to mother ramets was more pronounced when daughter ramets were treated with N *** ^(13)C-photosynthates that were translocated from mother ramets without and with N addition were mainly invested in the leaves and roots of daughter ramets with N addition,from daughter ramets with N addition were mainly invested in the leaves and roots of mother ramets with and without N addition,*** results suggest that mother ramets preferentially invest more resources in nutrient-rich daughter ramets,and that daughter ramets serve as efficient resource acquisition sites to specialize in acquiring abundant resources based on the resource conditions of mother *** plants can improve their resource acquisition efficiency and maximize the overall performance in this way.

关键词： carbon allocation habitat heterogeneity ^(13)C-CO_(2)labeling resource integration Moso bamboo

Occurrence modes of silver in the Ni-Mo-PGE polymetallic layer of the Lower Cambrian black shales in Zunyi, Guizhou Province, South China

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

Chinese Journal Of Geochemistry 2014年第4期33卷 387-392页

作者： HAN Tao ZHU Xiaoqing liu shirong LI Xiaoxia State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The Ni-Mo-PGE polymetallic mineralization of the Lower Cambrian black shales locate in Zunyi, South China and contain abundant noble metals such as Ag, Au and PGE, and especially Ag with average concentration of 64×10-6. The occurrence modes of Ag have been investigated using methods of selective chemical dissolution and transmission electron microscopy. The results demonstrate that the occurrence modes of Ag are complex and diversiform. It might be associated with clay minerals, organic matter, sulfides and also occurred as native silver and sulfides with nanometer in size. Combined with results of previous studies, we suggest that the sulfides, clay minerals and organic matter which hosted in the Ni-Mo-PGE polymetallic ores of black shales can play the roles of important reduction and adsorption geochemical barriers for the enrichment and distribution of silver. This study further implies that the selective chemical dissolution and transmission electron microscopy may pave the way to study the occurrence modes of other noble metals in black shales.

关键词：多金属矿化黑色页岩下寒武统中国南方 PGE 白银镍钼遵义

Assessing stand structure in successional stages of dark coniferous forests in western Sichuan, China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2016年第4期27卷 779-786页

作者： Jiangming Ma shirong liu Zuomin Shi Jingxin Wang Key Laboratory of Forest Ecology and Environment State Forestry Administration Institute of Forest EcologyEnvironment and Protection Chinese Academy of Forestry College of Life Science Guangxi Normal University Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University) Ministry of Education China Division of Forestry and Natural Resources West Virginia University

Subalpine dark coniferous forests in the western Sichuan Province of China play an important role in the hydrological processes in the upper reaches of the Yangtze River. Second-growth forests, with different stand successional stages, have developed as a result of logging over the past 50 years. Forest cover and stand structure changed greatly with concomitant degradation of forest ecosystem functions. To understand how the stand structures of the second-growth forests change during the stand succession process, we analyzed stand structure characteristics and an old-growth state index of the bamboo and moss-forest types. We found that stand structure at the young successional stage featured one-third of the structure characteristics of the old-growth dark coniferous forests,while the structure of the medium-aged stage had reached half the structure of the old-growth state. The two forest types were similar in the rate of development at the young successional stage but differed at the medium-aged stage;the moss-forest type had more advanced development than the bamboo-forest type at the medium-aged successional stage.

关键词： stand forests bamboo leaved ecosystem logging young Yangtze succession shrub

Forest management required for consistent carbon sink in China’s forest plantations

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2021年第4期8卷 726-734页

作者： Zhen Yu Weibin You Evgenios Agathokleous Guoyi Zhou shirong liu Institute of Ecology Jiangsu Key Laboratory of Agricultural MeteorologyNanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory of Forest Ecology and Environment China’s National Forestry and Grassland AdministrationInstitute of Forest EcologyEnvironment and ProtectionChinese Academy of ForestryBeijing 100091China College of Forestry Fujian Agriculture and Forestry UniversityFuzhou 350002China

Background:Forest is the largest biomass carbon(C)pool in China,taking up a substantial amount of atmospheric carbon *** it is well understood that planted forests(PFs)act as a large C sink,the contribution of human management to C storage enhancement remains ***,existing projections of forest C dynamics suffer from spatially inconsistent age and type information or neglected human management *** this study,using developed PF age and type maps and data collected from 1371 forest plantation sites in China,we simulated biomass C stock change and quantified management impacts for the time period ***:Results show that future forest biomass C increment might have been overestimated by 32.5%-107.5% in former *** also found that age-related growth will be by far the largest contributor to PF biomass C increment from 2010 to 2050(1.23±0.002 Pg C,1 Pg=10^(15) g=1 billion metric tons),followed by the impact of human management(0.57±0.02 Pg C),while the contribution of climate is slight(0.087±0.04 Pg C).Besides,an additional 0.24±0.07 Pg C can be stored if current PFs are all managed by 2050,resulting in a total increase of 2.13±0.05 Pg ***:Forest management and age-related growth dominate the biomass C change in PFs,while the effect of climatic factors on the accumulation is *** achieve the ambitious goal of forest C stock enhancement by 3.5 Pg from 2020 to 2050,we advocate to improve the management of existing forests and reduce the requests for more lands for forest expansion,which helps mitigate potential conflicts with agricultural *** results highlight that appropriate planning and management are required for sustaining and enhancing biomass C sequestration in China’s PF.

关键词： Planted forest Human management Forest biomass carbon Forest age Forest expansion Climate change

Nutrient resorption strategies of three oak tree species in response to interannual climate variability

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2021年第4期8卷 937-947页

作者： Baoming Du Huawei Ji shirong liu Hongzhang Kang Shan Yin Chunjiang liu School of Agriculture and Biology Shanghai Jiao Tong University200240 ShanghaiChina Key Laboratory of Forest Ecology and Environment China’s State Forestry AdministrationResearch Institute of Forest EcologyEnvironment and ProtectionChinese Academy of Forestry100091 BeijingChina Shanghai Urban Forest Ecosystem Research Station State Forestry Administration200240 ShanghaiChina Shanghai Yangtze River Delta Eco-environmental Change and Management Observation and Research Station Ministry of Science and Technology200240 ShanghaiChina

Background:Nutrient resorption is critical for plants toward balancing their nutritional requirements and adapting to environmental variabilities,which further impacts litter quality and nutrient ***,the interannual variability of nutrient resorption under climate change remains ***:We investigated the five-year nutrient resorption efficiencies(NuRE,%)of 14 elements in three deciduous oak tree species(Quercus aliena ***,***,and ***)in a warm-temperate forest of Central China and assessed their relationships with interannual climate and soil ***:Nutrient resorption did not differ between species but varied significantly between different *** each year,N,P,S,K,C,Mg,and Zn were preferentially resorbed in all of the oak species in contrast to Ca,Na,Mn,Ba,Al,Fe,Cu,which were to some extent *** the 14 elements,the NuRE of C,N,P,S,Ca,and Mg was more sensitive to interannual climate variations in the three oak *** carbon resorption efficiency was significantly increased during the driest year of the study(2014);N resorption efficiency was reduced with temperature;whereas N and P resorption efficiency initially decreased and then increased with ***,the elements with higher NuREs typically had lower coefficient of variation(CV)in all three oak ***:Different oak species exhibited analogous nutrient conservation strategies in response to annual climate variabilities,and interannual climate variations strongly impacted plant nutrient *** plants may establish a tradeoff mechanism to rebalance somatic nutrients for regrowth at the end of the growing season.

关键词： Nutrient resorption Tradeoff mechanism Climate change Quercus spp. Temperate forests

Multi-year throughfall reduction enhanced the growth and non-structural carbohydrate storage of roots at the expenses of above-ground growth in a warm-temperate natural oak forest

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2023年第3期10卷 357-367页

作者： Cuiju liu Zhicheng Chen shirong liu Kunfang Cao Baoliang Niu Xiaojing liu Xiaomin Gao Key Laboratory of Forest Ecology and Environment National Forestry and Grassland AdministrationEcology and Nature Conservation InstituteChinese Academy of ForestryBeijing100091China Baotianman Forest Ecosystem Research Station Nanyang473000China Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning530004China Henan Baotianman Nature Reserve Administration Neixiang474350China

The more frequent occurrence and severer drought events resulting from climate change are increasingly affecting the physiological performance of trees and ecosystem carbon sequestration in many regions of the ***,our understanding of the mechanisms underlying the responses and adaption of forest trees to prolonged and multi-year drought is still *** address this problem,we conducted a long-term manipulative throughfall reduction(TFR,reduction of natural throughfall by 50%–70%during growing seasons)experiment in a natural oriental white oak(Quercus aliena *** Maxim.)forest under warm-temperate *** seven years of continuous TFR treatment,the aboveground growth in *** *** started to *** with the control plots,trees in the TFR treatment significantly reduced growth increments of stems(14.2%)and leaf area index(6.8%).The rate of net photosynthesis appeared to be more susceptible to changes in soil water in trees subjected to the TFR than in the *** TFR-treated trees allocated significantly more photosynthates to belowground,leading to enhanced growth and nonstructural carbohydrates(NSC)storage in *** 7-year continuous TFR treatment increased the biomass,the production and the NSC concentration in the fine roots by 53.6%,153.6%and 9.6%,*** were clear trade-offs between the aboveground growth and the fine root biomass and NSC storage in *** *** trees in response to the multi-year TFR treatment.A negative correlation between the fine root NSC concentration and soil water suggested a strategy of preferential C storage over growth when soil water became deficient;the stored NSC during water limitation would then help promote root growth when drought stress is *** findings demonstrate the warm-temperate oak forest adopted a more conservative NSC use strategy in response to long-term drought stress,with enhanced root growth and NSC storage at the exp

关键词： Climate change Carbon allocation Drought stress Forest ecophysiology Nonstructural carbohydrates Warm-temperate forests