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Contribution of winter fluxes to the annual CH_4, CO_2 and N_2O emissions from fres hwater marshes in the Sanjiang Plain

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Journal of Environmental Sciences 2006年第2期18卷 270-275页

作者： HAO Qing-ju WANG Yue-si song chang-chun HUANG Yao Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Northeast Institute of Geography and Agricultural Ecology Chinese Academy of Sciences Changchun 130012 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

Wetlands at the interface of the terrestrial and aquatic ecosystems are intensive sites for mineralization of organic matter, but the contribution of winter season fluxes of CH4, CO2 and N2O from wetland ecosystems to annual budgets is poorly known. By using the static opaque chamber and GC techniques, fluxes of CH4, CO2 and N2O at two freshwater marshes in the Sanjiang Plain were measured during the winter seasons of 2002/2003 and 2003/2004 with contrasting snow conditions and flooding regimes. The results showed that there were significant interannual and spatial differences in CH4, CO2 and N2O fluxes. The Carex lasiocarpa marsh emitted more CH4 and CO2 while absorbed less N2O than the Deyeuxia angustifolia marsh during the winter seasons. Over the winter season, emissions of CH4, CO2 and N2O ranged from 0.42 to 2.41 gC/m^2, from 24.13 to 50.16 gC/m^2, and from -25,20 to -148.96 mgN/m^2, respectively. The contributions of winter season CH4 and CO2 emission to the annual budgets were 2.32% 4.62% and 22.17%- 27.97%, respectively. Marshes uptake N2O during the freezing period, while release N2O during the thawing period. The winter uptake equaled to 13.70%-86.69% of the growing-season loss. We conclude that gas exchange between soil/snow and the atmosphere in the winter season contributed greatly to the annual budgets and cannot be ignored in a cool temperate freshwater marsh in Northeast China.

关键词： freshwater marsh winter flux greenhouse gas emission Sanjiang Plain

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THE STUDY ON LATENT AND SENSIBLE HEAT FLUX OVER MIRE IN THE SANJIANG PLAIN

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湿地科学 2006年第1期4卷 13-20页

作者： JIA Zhi-Jun song chang-chun SUN Li Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun Jilin 130012 P.R. China Graduate school of Chinese Academy of Sciences Beijing 100049 P.R. China

S:Understanding how surface energy fluxes respond to environmental variables and how their components vary on daily and seasonal temporal scales are critical for understanding the ecological process of wetland ecosystem. In view of the fact that studies on surface energy flux over mire in China have been very limited, we have initiated a long-term latent and sensible heat flux (two main components of the surface energy balance) observation over mire in the Sanjiang Plain from June to October in 2004 with the eddy covariance technique. Results showed that the latent and sensible heat flux had large seasonal and diurnal variation during the period of measurement. Generally, latent heat flux between the mire wetland and the atmosphere reached the maximum value in June and then gradually decreased from June to October, whose daily mean fluxes were 9.83,8.00,7.33, 4.82 and 2.04 MJ/(m^2·d), respectively. By comparison, sensible heat flux changed unnoticeably with season change from June to October, which were 1.47,0.88,1.75, 1.61,1.33 MJ/(m^2·d) respectively. The diurnal variation of both latent and sensible heat flux varied noticeably within a day. After the sunrise, the latent and sensible heat flux increased and reached the maximum at noon (11:00-13:00). Then they decreased gradually and reached the minimum value during the nighttime. The patterns of temporal variation in latent and sensible heat flux were significantly controlled by environmental factors. The latent heat flux was linearly dependent on net radiation and increased with increasing vapour pressure deficit until the vapour pressure deficit surpassed 11 hPa. Wind speed effect on latent heat flux was more complicated and, in general, showed a positive correlation between them in daytime. The sensible heat flux was controlled mainly by air temperature difference between the land surface and the overlying air. However, when the temperature difference was larger than 0.3 ℃, it had no effect on the sensible heat

关键词：热流湿地净辐射能量风速气温

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EFFECT OF CARBON AVAILABILITY ON MICROBIAL ACTIVITIES IN Calamagrostis angustifolia SOIL

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湿地科学 2004年第1期2卷 68-73页

作者： XU Xiao-Feng song chang-chun song Xia YANG Huai-Hui NortheastInstituteofGeographyandAgriculturalEcology CASChangchunJilin130012China InstituteofGeographicScienceandNaturalResourceResearch CASBeijing100101China GeologicalExploituringandMiningBureauinHenan fiaozuoHenan471000China

S:Carbon availability varies very much along soil profile and decreases from topsoil to subsoil. The effect of carbon availability index (CAI) on microbial activities in Calamagrostis angustifolia soil in the Sanjiang Plain in the Northeast China was measured. Based on the proposal about CAI and microbial respiration from Parkinson and Coleman (1999), the results showed that carbon availability limits the microbial activities in topsoil, root layer soil and subsoil initially, whereas it does not limit the microbial activity after 1.5 h incubation for recovery from the disturbance in physical, chemical and biology structure resulting from sampling, then after 5h incubation carbon availability limits microbial activity again after the labile carbon was mineralized. At the same time the soil organic matter affects the carbon availability significantly when it is lower than 10%, but little when the soil organic matter is higher than 10%. The microbial biomass carbon is linearly related to carbon availability in the Calamagrostis angustifolia soil. When the CAI is lower than 0.85, the β-glucosidase activity increases along with CAI, but decreases when CAI is larger than 0.85.

关键词：碳微生物三江平原土壤湿地系统生态环境

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SUSTAINABLE AGRICULTURE DEVELOPMENT IN SALINE-ALKALI SOIL AREA OF songNEN PLAIN,NORTHEAST CHINA

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Chinese Geographical Science 2003年第2期13卷 171-174页

作者： WANG Zhi-chun, LI Qu-sheng, LI Xiu-jun, song chang-chun, ZHANG Guang-xin (Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, changchun 130012, P. R. China) Northeast Institute of Geography and Agricultural Ecology Chinese Academy of Sciences Changchun P. R. China

There is great potential for agriculture in saline-alkali soil area in songnen Plain, Northeast China. But the sustainable crop production in this area has been restricted by a few of main factors, such as less precipitation, h igher evaporation and frequent drought, high salinity and alkalinity, high excha ngeable sodium content and poor infiltration of the soil, and insufficiency and low availability in nutrition. It is also considered that there are a few of fav orable conditions for agricultural development in this region, such as sufficien t light and heat resources, rich ground water resources, plenty of manure produc ed by livestock, and so on. At the same time, scientific management and measurem ents have been employed; rational irrigation and drainage system has been establ ished; reclamation, amendment and fertilization of soil, and suitable strategies of cropping practices have been made for the sustainable development of agricul ture. Great progress has been made during 1996-2000.

关键词： sustainable agriculture development saline-alkali soil songnen plain

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三江平原典型沼泽湿地能量平衡和蒸散发研究

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水科学进展 2008年第1期19卷 43-48页

作者：孙丽宋长春中国科学院东北地理与农业生态研究所

基于涡度相关技术对三江平原典型沼泽湿地的水热通量进行了连续观测，研究沼泽湿地能量平衡和蒸散发的季节变化，确定观测期内沼泽湿地总蒸散量，并通过逐步回归方程估算沼泽湿地水面蒸发和植被蒸腾。结果表明，沼泽湿地的能量平衡具有... 详细信息

基于涡度相关技术对三江平原典型沼泽湿地的水热通量进行了连续观测，研究沼泽湿地能量平衡和蒸散发的季节变化，确定观测期内沼泽湿地总蒸散量，并通过逐步回归方程估算沼泽湿地水面蒸发和植被蒸腾。结果表明，沼泽湿地的能量平衡具有明显的季节变化特征，总体看来，潜热通量是湿地的主要能量支出项，占净辐射的45.5％，感热通量和存储热通量分别占净辐射的27.9％和26.7％。2006年5～10月份沼泽湿地总蒸散量为310.6mm，月均日蒸散量最高值出现在7月。观测期内沼泽湿地水面蒸发量约为221mm，占总蒸散量的71％左右，植被蒸腾量则约占总蒸散量的29％，湿地蒸散发以水面蒸发为主。

关键词：三江平原沼泽湿地能量平衡蒸散发蒸发植被蒸腾

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Inverse-time Backup Protection Based on Unified Characteristic Equation for Distribution Networks with High Proportion of Distributed Generations

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 202-212页

作者： Nana chang Guobing song Zhongxue chang Yuping Zheng Xingang Yang the School of Electrical Engineering Xi’an Jiaotong UniversityXi’anChina State Key Laboratory of Smart Grid Protection and Control NARI Group CorporationNanjingChina Electric Power Research Institute of State Grid Shanghai Electric Power Company ShanghaiChina

The setting work of backup protection using steady-state current is tedious,and mismatches occasionally occur due to the increased proportion of distributed generations(DGs)connected to the power ***,there is a practical need to study a backup protection technology that does not require step-by-step setting and can be adaptively *** paper proposes an action sequence adaptive to fault positions that uses only positive sequence fault component(PSFC)*** the influence of DGs,the unified time dial setting can be obtained by selecting specific *** protection performance is improved by using the adjacent upstream and downstream protections to meet the coordination time interval in the case of metallic faults at the near-and far-ends of the ***,the expression and implementation scheme for inverse-time backup protection(ITBP)based on the unified characteristic equation is *** results show that this scheme can adapt to DG penetration scenarios and can realize the adaptive coordination of multi-level relays.

关键词： Inverse-time backup protection(ITBP) distributed generation(DG) positive sequence fault component(PSFC)voltage unified characteristic equation adaptive coordination

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Photoluminescent nickel(Ⅱ)carbene complexes with ligand-to-ligand charge-transfer excited states

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Chinese Chemical Letters 2024年第1期35卷 357-360页

作者： chun-Liang Hou Jia-Xi song Xiaoyong chang Yong Chen Key Laboratory of Photochemical Conversion and Optoelectronic Materials&CAS-HKU Joint Laboratory on New Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China

While nickel(II)complexes have been widely used as catalysts for carbon-carbon coupling reactions,the exploration of their photophysical and photochemical properties is still in the ***,a series of square-planar Ni(II)complexes[(diNHC)NiX2]bearing chelating benzimidazole-based bis(N-heterocyclic carbene)ligands and varying anionic coligands(1,X=Cl;2,X=Br;3,X=I)are synthesized and structurally *** solid state,both 1 and 2 exhibit orange-red photoluminescence under ambient *** photophysical and electrochemical measurements along with density functional theory(DFT)calculations reveal that the low-energy emissions can be attributed to singlet excited states with ligand-to-ligand charge-transfer(LLCT)*** work suggests that strong-field N-heterocyclic carbene ligands play a crucial role to achieve the luminescence of Ni(II)complexes.

关键词： Nickel(II)complexes N-Heterocyclic carbene Luminescence Ligand-to-ligand charge-transfer character Low-lying d-d excited states

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三江平原典型沼泽湿地蒸散发估测

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应用生态学报 2008年第9期19卷 1925-1930页

作者：孙丽宋长春中国科学院东北地理与农业生态研究所

2006年5-9月,利用涡度相关技术对三江平原典型沼泽湿地蒸散发进行了连续观测,在分析生长季内沼泽湿地蒸散发时间动态的基础上,采用Penman-Monteith(PM)和Priest-ley-Taylor(PT)模型分别模拟了沼泽湿地的日蒸散发,并利用实测值对两种模... 详细信息

2006年5-9月,利用涡度相关技术对三江平原典型沼泽湿地蒸散发进行了连续观测,在分析生长季内沼泽湿地蒸散发时间动态的基础上,采用Penman-Monteith(PM)和Priest-ley-Taylor(PT)模型分别模拟了沼泽湿地的日蒸散发,并利用实测值对两种模型的模拟精度进行了验证.结果表明:生长季内(5-9月),研究区沼泽湿地蒸散发具有明显的季节变化,月均日蒸散量在5月最低、7月最高;生长季内平均蒸散发为1.94mm.d-1,总蒸散量293mm.生长季前期和后期,与蒸散发实测值相比,PM模型的模拟值存在明显低估现象;PT模型模拟值与实测值在整个生长季内的一致性较好,且PT模型的形式简单、所需参数少,更适于沼泽湿地的蒸散发模拟.

关键词：沼泽湿地蒸散发涡度相关法模型模拟

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磷输入对湿地土壤有机碳矿化及可溶性碳组分的影响

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中国环境科学 2008年第9期28卷 769-774页

作者：刘德燕宋长春中国科学院东北地理与农业生态研究所吉林长春130012 中国科学院研究生院北京100049

采用室内培养试验,研究了土壤非淹水(土壤含水量为田间最大持水量60%)和淹水条件下,外源磷输入对沼泽湿地土壤有机碳矿化和土壤可溶性有机碳(DOC)及可溶性无机碳(DIC)含量的影响.结果表明,不同土壤水分条件下,土壤有机碳的矿化速率和累... 详细信息

采用室内培养试验,研究了土壤非淹水(土壤含水量为田间最大持水量60%)和淹水条件下,外源磷输入对沼泽湿地土壤有机碳矿化和土壤可溶性有机碳(DOC)及可溶性无机碳(DIC)含量的影响.结果表明,不同土壤水分条件下,土壤有机碳的矿化速率和累积矿化量均随着外源磷输入量的增加而增大;培养65d后,土壤DOC含量表现为先降低后升高,而DIC含量则逐渐增大.不同磷处理下土壤有机碳的累积矿化量与土壤DOC含量之间的相关关系并不显著,但是与土壤DIC含量之间呈显著的正相关关系[R为0.98(淹水),0.99(非淹水);P<0.05].相同磷输入水平下,淹水处理时土壤有机碳的累积矿化量、DOC和DIC含量均高于非淹水处理.外源磷输入沼泽湿地后,会通过提高土壤有机碳的矿化速率和土壤可溶性碳组分的淋失,加快土壤有机碳的损失速率及土壤CO2的排放量.

关键词：磷输入矿化土壤有机碳可溶性有机碳(DOC) 可溶性无机碳(DIC)

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A deep learning interatomic potential suitable for simulating radiation damage in bulk tungsten

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Tungsten 2024年第2期6卷 304-322页

作者： chang-Jie Ding Ya-Wei Lei Xiao-Yang Wang Xiao-Lin Li Xiang-Yan Li Yan-Ge Zhang Yi-chun Xu chang-song Liu Xue-Bang Wu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island University of Science and Technology of ChinaHefei 230026China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.

关键词： Machine learning Deep learning Interatomic potential Radiation damage Tungsten

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