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Theoretical studies of C_(36) encapsulated in zigzag single-wall carbon nanotubes

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Chinese Science Bulletin 2006年第1期51卷 25-30页

作者： yang Baohua WANG yang HUANG yuanhe Department of Chemistry Beijing Normal University Beijing 100875China

The one-dimensional hybrid structures of C36 encapsulated in zigzag single-wall carbon nanotubes (C36@(n,0)) have been investigated using ab initio self-consistent-field crystal orbital method based on the density functional theory. The research focuses on the change of geometric and band struc- tures for the nanotubes upon C36 encapsulation. The obtained results show that the introduction of C36 can modify the electronic properties of CNT. The diameter of carbon nanotube plays an important role in the geometric and electronic properties of the peapod structures.

关键词：碳纳米管理论研究制备密度功能理论

Variations of root and heterotrophic respiration along environmental gradients in China’s forests

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Journal of Plant Ecology 2013年第5期6卷 358-367页

作者： Pin Li yuanhe yang Jingyun Fang Department of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Aims Root and heterotrophic respiration may respond differently to environmental variability,but little evidence is available from largescale *** we aimed to examine variations of root and heterotrophic respiration across broad geographic,climatic,soil and biotic *** We conducted a synthesis of 59 field measurements on root and heterotrophic respiration across China’s *** Findings Root and heterotrophic respiration varied differently with forest types,of which evergreen broadleaf forest was significantly different from those in other forest types on heterotrophic respiration but without statistically significant differences on root *** results also indicated that root and heterotrophic respiration exhibited similar trends along gradients of precipitation,soil organic carbon and satellite-indicated vegetation ***,they exhibited different relationships with temperature:root respiration exhibited bimodal patterns along the temperature gradient,while heterotrophic respiration increased monotonically with ***,they showed different relationships with MOD17 GPP,with increasing trend observed for root respiration whereas insignificant change for heterotrophic *** addition,root and heterotrophic respiration exhibited different changes along the age sequence,with insignificant change for root respiration and decreasing trend for heterotrophic ***,these results suggest that root and heterotrophic respiration may respond differently to environmental *** findings could advance our understanding on the different environmental controls of root and heterotrophic respiration and also improve our ability to predict soil CO_(2) flux under a changing environment.

关键词： enhanced vegetation index forest age heterotrophic respiration latitude mean annual temperature mean annual precipitation root respiration GPP

Patterns of above-and belowground biomass allocation in China's grasslands:Evidence from individual-level observations

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Science China(Life Sciences) 2010年第7期53卷 851-857页

作者： WANG Liang NIU KeChang yang yuanhe ZHOU Peng Department of Ecology Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China

Above-and belowground biomass allocation not only influences growth of individual plants,but also influences vegetation structures and functions,and consequently impacts soil carbon input as well as terrestrial ecosystem carbon ***,due to sampling difficulties,a considerable amount of uncertainty remains about the root:shoot ratio(R/S),a key parameter for models of terrestrial ecosystem carbon *** investigated biomass allocation patterns across a broad spatial *** collected data on individual plant biomass and systematically sampled along a transect across the temperate grasslands in Inner Mongolia as well as in the alpine grasslands on the Tibetan *** results indicated that the median of R/S for herbaceous species was 0.78 in China's grasslands as a whole.R/S was significantly higher in temperate grasslands than in alpine grasslands(0.84 vs.0.65).The slope of the allometric relationship between above-and belowground biomass was steeper for temperate grasslands than for *** results did not support the hypothesis that aboveground biomass scales isometrically with belowground *** R/S in China's grasslands was not significantly correlated with mean annual temperature(MAT) or mean annual precipitation(MAP).Moreover,comparisons of our results with previous findings indicated a large difference between R/S data from individual plants and *** might be mainly caused by the underestimation of R/S at the individual level as a result of an inevitable loss of fine roots and the overestimation of R/S in community-level surveys due to grazing and difficulties in identifying dead *** findings suggest that root biomass in grasslands tended to have been overestimated in previous reports of R/S.

关键词： aboveground biomass allometry alpine grassland belowground biomass Inner Mongolia isometric relationship root:shoot ratio temperate grassland Tibetan Plateau

Global patterns and climatic drivers of above-and belowground net primary productivity in grasslands

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Science China(Life Sciences) 2021年第5期64卷 739-751页

作者： Yuanfeng Sun yuanhe yang Xia Zhao Zhiyao Tang Shaopeng Wang Jingyun Fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Understanding patterns and determinants of net primary productivity(NPP)in global grasslands is ongoing challenges,especially for belowground NPP(BNPP)and its fraction(fBNPP).By developing a comprehensive field-based dataset,we revealed that,along with gradients of mean annual precipitation,actual evapotranspiration,and aridity,aboveground NPP(ANPP),BNPP,and total NPP(TNPP)exhibited hump-shaped patterns,whereas fBNPPshowed an opposite *** and TNPP showed positive correlations with mean annual temperature,but fBNPPwas negatively correlated with *** relationship between BNPP and climatic factors was considerably weak,indicating that BNPP was relatively stable regardless of the climate *** also observed that the sensitivities of ANPP and BNPP to interannual temperature variability and those of BNPP to interannual precipitation fluctuations exhibited large variations among different study sites,and differed from those at the spatial *** contrast,the temporal sensitivities of ANPP to interannual precipitation variability were highly similar across all the individual sites and much smaller than those at the spatial ***,these results highlight that precipitation,temperature and evapotranspiration all play vital roles in shaping ANPP pattern and its partitioning to belowground and that the patterns of BNPP along climatic gradients do not mirror those of the ANPP.

关键词： net primary productivity productivity partition climate change grasslands precipitation temperature

Inverse analysis of coupled carbon-nitrogen cycles against multiple datasets at ambient and elevated CO_(2)

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Journal of Plant Ecology 2016年第3期9卷 285-295页

作者： Zheng Shi yuanhe yang Xuhui Zhou Ensheng Weng Adrien C.Finzi Yiqi Luo Department of Botany and Microbiology University of OklahomaNormanOK 73019USA State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Department of Biology Boston UniversityBostonMA 02215USA

Aims Carbon(C)sequestration in terrestrial ecosystems is strongly regulated by nitrogen(N)***,key parameters that determine the degree of N regulation on terrestrial C sequestration have not been well *** Here,we used a Bayesian probabilistic inversion approach to estimate 14 target parameters related to ecosystem C and N interactions from 19 datasets obtained from Duke Forests under ambient and elevated carbon dioxide(CO_(2)).Important FindingsOur results indicated that 8 of the 14 target parameters,such as C:N ratios in most ecosystem compartments,plant N uptake and external N input,were well constrained by available datasets whereas the others,such as N allocation coefficients,N loss and the initial value of mineral N pool were poorly *** analysis showed that elevated CO_(2)led to the increases in C:N ratios in foliage,fine roots and ***,elevated CO_(2)stimulated plant N uptake and increased ecosystem N capital in Duke Forests by 25.2 and 8.5%,*** addition,elevated CO_(2)resulted in the decrease of C exit rates(*** in C residence times)in foliage,woody biomass,structural litter and passive soil organic matter,but the increase of C exit rate in fine *** results demonstrated that CO_(2)enrichment substantially altered key parameters in determining terrestrial C and N interactions,which have profound implications for model improvement and predictions of future C sequestration in terrestrial ecosystems in response to global change.

关键词： Bayesian probabilistic inversion carbon-nitrogen interactions carbon-nitrogen coupled model Duke FACE.

Permafrost carbon cycle and its dynamics on the Tibetan Plateau

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Science China(Life Sciences) 2024年第9期67卷 1833-1848页

作者： Leiyi Chen Guibiao yang Yuxuan Bai Jinfeng Chang Shuqi Qin Futing Liu Mei He Yutong Song Fan Zhang Josep Penuelas Biao Zhu Guoying Zhou yuanhe yang State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China China National Botanical Garden Beijing 100093China College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058China Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing 100091China University of Chinese Academy of Sciences Beijing 100049China Consejo Superior de Investigaciones Científicas(CSIC) Global Ecology Unit CREAF-CSIC-UAB(Universitat Autònoma de Barcelona)Barcelona 08193Spain Centre for Ecological Research and Forestry(CREAF) Barcelona 08193Spain Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China Northwest Institute of Plateau Biology Chinese Academy of SciencesXining 810008China Key Laboratory of Tibetan Medicine Research Chinese Academy of SciencesXining 810008China

Our knowledge on permafrost carbon(C)cycle is crucial for understanding its feedback to climate warming and developing nature-based solutions for mitigating climate *** understand the characteristics of permafrost C cycle on the Tibetan Plateau,the largest alpine permafrost region around the world,we summarized recent advances including the stocks and fluxes of permafrost C and their responses to thawing,and depicted permafrost C dynamics within this *** find that this alpine permafrost region stores approximately 14.1 Pg(1 Pg=1015g)of soil organic C(SOC)in the top 3 *** substantial gaseous emissions and lateral C transport occur across this permafrost ***,the mobilization of frozen C is expedited by permafrost thaw,especially by the formation of thermokarst landscapes,which could release significant amounts of C into the atmosphere and surrounding water *** alpine permafrost region nevertheless remains an important C sink,and its capacity to sequester C will continue to increase by *** future perspectives,we would suggest developing long-term in situ observation networks of C stocks and fluxes with improved temporal and spatial coverage,and exploring the mechanisms underlying the response of ecosystem C cycle to permafrost *** addition,it is essential to improve the projection of permafrost C dynamics through in-depth model-data fusion on the Tibetan Plateau.

关键词： permafrost carbon climate change carbon release carbon sink permafrost thaw thermokarst formation

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论中国茶书中关于茶树种植的生态智慧

农业考古 2021年第5期 202-207页

作者：杨源禾云南农业大学马克思主义学院

农耕生产孕育了中国古代生态智慧,自然崇拜是中国古代生态观念的萌芽。本文对中国古代茶书进行研究,发现在一段较长的历史时空里,中国古代特殊的茶树种植技术经过地方性的选择、组合与传播自成一套体系,形成了自己独特的文化结构,蕴含... 详细信息

农耕生产孕育了中国古代生态智慧,自然崇拜是中国古代生态观念的萌芽。本文对中国古代茶书进行研究,发现在一段较长的历史时空里,中国古代特殊的茶树种植技术经过地方性的选择、组合与传播自成一套体系,形成了自己独特的文化结构,蕴含着优良的生态智慧,体现出传统的生态实践,有别于现代众多规模化台地茶种植园。中国传统茶树种植的生态智慧,对当今世界生态文明建设和可持续发展具有重要启示意义。

关键词：古代茶书茶树种植生态智慧

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青藏高原植被活动对降水变化的响应

北京大学学报（自然科学版） 2007年第6期43卷 771-775页

作者：周睿杨元合方精云北京大学城市与环境学院生态学系北京大学地表过程分析与模拟教育部重点实验室北京100871

为揭示气候变异对青藏高原植被生长的影响,根据2000—2004年间增强型植被指数(EVI)数据和研究区内43个气象台站的气候资料,研究了近5年来青藏高原植被活动及其与气候因子的关系。结果显示,青藏高原植被的EVI呈现由东南向西北递减的分布... 详细信息

为揭示气候变异对青藏高原植被生长的影响,根据2000—2004年间增强型植被指数(EVI)数据和研究区内43个气象台站的气候资料,研究了近5年来青藏高原植被活动及其与气候因子的关系。结果显示,青藏高原植被的EVI呈现由东南向西北递减的分布格局,降水是导致植被覆盖空间变化的主要因素;2000—2004年青藏高原植被活动的年际变化总体上不显著,局部出现较大变异;EVI的变异系数(CV)与年降水的变异系数显著正相关,说明降水波动是引起植被活动变化的主要因素。此外,EVI的CV与年降水量存在着显著的负相关关系,表明年降水量越大的地区植被活动的年际变化越小,即植被的稳定性越大。

关键词：青藏高原 EVI 时间变异降水

Impact of global warming on drought in China

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Research in Cold and Arid Regions 2012年第3期4卷 201-210页

作者： Xian Xue Tao Wang Jian Guo yuanhe yang Fei Peng LiChao Liu Key Laboratory of Desert and Desertification CoM and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China Department of Botany and Microbiology University of Oklahoma Norman OK 73019 USA

Spatial and temporal change pattems of air temperature （7）, precipitation （P）, relative humidity （RH）, lower vapor pressure （VP）, potential evapotranspiration （PET） and drought situation of 690 meteorological stations for all of China were evaluated in this study to understand the effects of warming on regional drought and hydrological processes. Here, the drought extent is expressed by aridity index （AI）, which is the ratio of precipitation and reference crop evapotranspiration （ETo） calculated by FAO Pen- man-Monteith equation, taking into account air temperature, atmospheric humidity, solar radiation, and wind. Our results indicate that there are different patterns of climate change from 1961 to 2008 and from 1981 to 2008. Little precipitation change occurred in China and ETo decreased from 1961 to 2008. But, the warming trend has intensified and the area with significant increasing precipitation has reduced since the early 1980＇s and ETo has increased in most areas of China from 1981 to 2008 and decreased from 1961 to 2008. The areas affected by drought have shifted from North China and Northeast China to East China and South China since 1981. It is speculated that the increasing warming intensity after 1981 possibly strengthened the power of potential evapotmnspiration and resulted in drought in most areas of Northeast China, North China, eastem Southwest China, and especially in East China and South China.

关键词： global warming temporal difference vapor deficit evapotranspiration drought China