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Journal of Plant Ecology 2019年第4期12卷 615-623页

作者： Tao Yan Jiaojun Zhu huanhuan song Kai Yang CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyShenyang 110016China Qingyuan Forest CERN Chinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China

Aims Larch is the dominant timber species in Northeast ***,compared with the adjacent secondary forests,soil available ni-trogen(N)significantly declined in~40-year-old larch ***,it is of great importance to determine how N use strategies in larch change in response to declining soil N *** We investigated the changes in N concentration and ^(15)N natural abundance(δ^(15)N)from 18 August to 25 October in the leaves,stems,branches and roots of 1-year-old Larix kaempferi seedlings under nutrient-sufficient(NSu)and nutrient-starvation(NSt)condi-tions with a pot experiment in Northeast *** Findings Stem and branch N concentrations exhibited upward trends,and leaf N concentration exhibited a downward *** N concentration exhibited an upward trend under NSu conditions,but a downward trend under NSt *** results suggested that stems and branches were served as N storage organs,but roots shifted from storage to resorption organs when switched from NSu to *** nutrient resorption was intensely occurred on 11 October,as indi-cated by the sharply decreased leaf N concentration and increased stem,root and branch N ***δ^(15)N of roots,branches and leaves overlapped between NSu and NSt approximately on 11 October,which may be regulated by isotope discrimination dur-ing N *** N resorption efficiency under NSt(76.33%)was significantly higher than that of NSu(56.76%),indicating that nutrient stress stimulates leaf N *** together,larch seedlings enhance leaf nutrient resorption and shift roots from nu-trient storage to nutrient resorption to adapt to NSt *** changes might relieve the adverse effects of declining soil nutrient availability on seedling survival and regeneration.

关键词： nutrient stress storage organ resorption organ redistribution stable nitrogen isotope

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Contrasting effects of N addition on the N and P status of understory vegetation in plantations of sapling and mature Larix principis-rupprechtii

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Journal of Plant Ecology 2018年第6期11卷 843-852页

作者： Tao Yan Tiantian Qu huanhuan song Philippe Ciais Shilong Piao Zhenzhong Sun Hui Zeng Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking University5 Yiheyuan RoadHaidian DistrictBeijing 100871China School of Urban Planning and Design Peking University2199 Lishui RoadNanshan DistrictShenzhen 518055China Institute of Applied Ecology Chinese Academy of Sciences72 Wenhua RoadShenhe DistrictShenyang 110016China Laboratoire des Sciences du Climat et de l’Environnement UMR 1572 CEA-CNRS-UVSQ91191 Gif-sur-YvetteFrance Key Laboratory of Alpine Ecology and Biodiversity Institute of Tibetan Plateau ResearchChinese Academy of Sciences16 Lincui RoadChaoyang DistrictBeijing 100085China Center for Excellence in Tibetan Earth Science Chinese Academy of Sciences16 Lincui RoadChaoyang DistrictBeijing 100085China

Aims The productivity of forest plantations in temperate areas is often lim-ited by nitrogen(N),but may shift towards phosphorus(P)limitation with increasing atmospheric N *** resorption is a nutrient conservation strategy in *** data on nutrient resorption are available for overstory trees,there are few data for understory *** We examined leaf N and P concentrations and N and P resorption efficiencies(NRE and PRE,respectively)in eight understory species in 11-and 45-year-old Larix principis-rupprechtii stands subjected to N supplementation over a 3-year *** findings Leaf N concentrations and N:P ratios increased and P concentrations decreased,with N input in species within the 45-year-old stand,but not in the 11-year-old *** and PRE were not altered by N input in any of the species in either stand,but N resorption pro-ficiency decreased and P resorption proficiency increased,in the species in the 45-year-old ***,the growth of understory species may be more P-limited in the 45-versus 11-year-old stand,and nutrient resorption proficiency was more sensitive to N add-ition than nutrient resorption *** results will improve the understanding of nutrient use strategies and their responses to N addition in understory *** contrasting effects of N addition on nutrient status between stand ages cannot be ignored when modeling ecosystem nutrient cycling under global N depos-ition conditions.

关键词： larch plantation N addition nutrient resorption stand age understory species

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Endovascular stent treatment of the iliac vein stenosis caused by a pelvic lymphocele secondary to gynecologic malignancy

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Journal of Interventional Medicine 2020年第4期3卷 192-194页

作者： Li Zhang Xiang Li Huaping Wu Kaiping Lv Cunliang Zeng huanhuan song Department of Vascular Surgery Dazhou Central HospitalDazhou635000PR China

Over the past two years,6 patients had iliac vein stenosis caused by radiation and pelvic lymphocele secondary to gynecologic *** had symptomatic lymphoceles induced lower limb *** treatment of symptomatic lymphoceles,compression symptoms persist,all patients were performed endovascular stent therapy,clinical symptoms of lower limb were completely *** vein stenosis caused by radiation and pelvic lymphocele secondary to gynecologic malignancy,endovascular stent placement is a nonsurgical alternative for the reestablishment of venous flow and sustained relief of symptoms.

关键词： Pelvic lymphocele Gynecologic malignancy Iliac vein stenosis Endovascular stent treatment

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Thoracic endovascular aortic repair with left subclavian artery reconstruction for blunt traumatic aortic injury in elderly patients

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Journal of Interventional Medicine 2019年第4期2卷 150-153页

作者： Li Zhang Huaping Wu Xiang Li Kaiping Lv huanhuan song Cunliang Zeng Jianlin Liu Department of Vascular Surgery Dazhou Central HospitalDazhou635000PR China Department of Vascular Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an710000PR China

Introduction:Blunt thoracic aortic injury(BTAI)is rare in elderly *** the population ages and life expectancy increases,the frequency of this injury will increase,while the treatment and outcomes remain ***:We retrospectively analyzed the collected data of patients>60 years old with BTAI to investigate the mechanism of trauma;time interval from injury to diagnosis;type and timing of surgical intervention;aortic arch pattern;choice of left subclavian artery reconstruction;endograft to treat BTAI;length of the endovascular procedure;endoleaks;complications including stroke,paraplegia,and renal failure;length of hospital stay(LOS)and intensive care unit stay(***);and 30-day ***:Five elderly trauma patients were found to have ***(80%)were males,the cohort mean age was68 years,the major mechanism of trauma was fall injury,and the associated injury was thoracic *** patients were transferred to our hospital,and emergency computed tomography angiography showed BTAI in each *** average time interval from injury to diagnosis was 2.7 *** patients suddenly showed signs of instability in their vital signs and underwent immediate endovascular repair,while 3 patients underwent delayed endovascular *** injury site was located in the aortic isthmus just distal to the origin of the left subclavian artery;the aortic arch pattern was II(80.0%)in 4 cases and III in 1 case(20.0%).The choice of left subclavian artery reconstruction included chimney,double chimney,prefenestration,and chimney combined with in situ *** to treat BTAI included the Ankura(Lifetech Scientific,Shenzhen,China)and the C-TAG(***&Associates,Flagstaff,AZ USA).The length of the endovascular procedure was 75.4 min;there were no endoleaks and no complications including stroke,paraplegia,or renal *** average LOS was25 days,and the average *** of 2 patients was 15 days,with no 30-day ***:Elderly patien

关键词： Blunt traumatic aortic injury Thoracic endovascular repair Reconstruction of left subclavian artery

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Research and Implementation of Text Similarity System Based on Power Spectrum Analysis

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Journal of Computer and Communications 2014年第6期2卷 7-17页

作者： Ying Xie Shouning Qu huanhuan song Information Network Center University of Jinan Jinan China School of Information Science and Engineering University of Jinan Jinan China

The paper proposed the research and implement of text similarity system based on power spectrum analysis. It is not difficult to imagine that the signals of brain are closely linked with writing process. So we build text modeling and set pulse signal function to get the power spectrum of the text. The specific detail is getting power spectrum from economic field to build spectral library, and then using the method of power spectrum matching algorithm to judge whether the test text belonged to the economic field. The method made text similarity system finish the function of text intelligent classification efficiently and accurately.

关键词： Pulsing Signal Function Power Spectrum Matching Algorithm Text Similarity System Text Intelligent Classification

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Pentacoordinate Phosphoranes as Versatile Reagents in Fluoroalkylation Reactions

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CCS Chemistry 2024年第1期6卷 165-176页

作者： huanhuan song Weihao Li Xiaoying Wang Kaiteng Wang Jingwen Li Shuai Liu Pin Gao Xin-Hua Duan Jinbo Hu Mingyou Hu School of Chemistry Engineering Research Center of Energy Storage Materials and DevicesMinistry of EducationXi’an Key Laboratory of Sustainable Energy Material ChemistryXi’an Jiaotong UniversityXi’an 710049 Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032

A general method for the synthesis of bench-stable bis(difluoromethyl)pentacoordinate phosphoranes has been *** reaction is rapid,operationally simple,and easily *** pentacoordinate phosphoranes can generate both difluoromethyl radical(·CF_(2)H)and difluorocarbene(:CF_(2))***,a variety of fluoroalkylation transformations havebeen achieved by·CF_(2)H,such asoxidativedifluoromethylation of electron-deficient heterocycles,nickel/photoredox dual-catalyzed difluoromethylation of aryl bromides,and photoredox difluoromethylation of alkenes,or by:CF_(2),such as gem-difluorocyclopropanation of alkenes,base-promoted difluoromethylation of heteroatom nucleophiles,Pd-catalyzed difluoromethylation of arylboronic acids,and Cu-mediated trifluoromethylation of aryl iodides(via:CF_(2) and recombined CF_(3)-).These fluoroalkylation methods have been successfully applied to late-stage fluoroalkylation of drugs and drug-like molecules.

关键词： pentacoordinate phosphorane difluoromethyl radical difluorocarbene difluoromethylation fluoroalkylation

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基于智能反射表面辅助的MIMO无线通信密钥快速生成

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电子与信息学报 2022年第7期44卷 2264-2272页

作者：唐杰文红宋欢欢王睿斐电子科技大学航空航天学院成都611731

近来,结合智能反射表面(IRS)辅助无线通信的密钥生成技术引发了学界的兴趣。然而目前的工作仅针对在单天线收发(SISO)系统中引入IRS辅助密钥生成,其IRS对密钥生成速率的提升效率不够高。针对此问题,该文研究了基于IRS结合MIMO系统的无... 详细信息

近来,结合智能反射表面(IRS)辅助无线通信的密钥生成技术引发了学界的兴趣。然而目前的工作仅针对在单天线收发(SISO)系统中引入IRS辅助密钥生成,其IRS对密钥生成速率的提升效率不够高。针对此问题,该文研究了基于IRS结合MIMO系统的无线密钥快速生成方案,通过控制IRS反射合法双发与IRS之间的MIMO信号来构建等效的快速信道,可更显著地提升密钥生成速率(KGR)。该文首先从信息论角度对所提方案的密钥速率和安全性进行了分析与证明,推导了密钥速率性能上界的表达式。基于此,从不同的窃听场景出发,分析窃听者分别靠近合法收发方和IRS进行窃听时,其靠近的距离对密钥生成速率性能的影响,发现所提方案在密钥速率和安全性能上均得到显著提升。最后,通过仿真验证了所提方案的有效性和理论分析的正确性。

关键词：无线网络安全智能反射表面物理层安全密钥生成 MIMO

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服务质量、技术创新与全球价值链地位攀升——来自中国的经验证据

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经济问题探索 2023年第3期 175-190页

作者：崔日明宋换换李丹辽宁大学金融与贸易学院沈阳110000

当前中国正处于制造业转型升级的关键时期,全球价值链高端攀升是制造业转型升级的本质所在。本文利用WIOD数据库,测算了中国制造业生产投入的服务质量水平,并在此基础上探究了投入服务质量对全球价值链地位的影响效应及其作用机制。研... 详细信息

当前中国正处于制造业转型升级的关键时期,全球价值链高端攀升是制造业转型升级的本质所在。本文利用WIOD数据库,测算了中国制造业生产投入的服务质量水平,并在此基础上探究了投入服务质量对全球价值链地位的影响效应及其作用机制。研究发现:投入服务质量对制造业全球价值链地位攀升具有显著的正向促进作用。区分投入服务来源后发现,投入的国内外服务质量均能显著促进制造业全球价值链地位攀升,但国外服务质量的促进效果更明显;区分投入服务结构后发现,不同类型服务质量都对制造业全球价值链地位攀升具有正向效应,但信息通讯和金融保险服务质量的效应更显著;区分制造业要素密集度后发现,劳动密集型制造业和资本密集型制造业投入的服务质量促进了全球价值链地位攀升,而知识密集型则表现出抑制作用;机制分析发现,技术创新是投入服务质量影响制造业全球价值链地位攀升的重要作用渠道。

关键词：投入的服务质量国内服务质量国外服务质量技术创新全球价值链地位

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随机移动终端协同干扰下的安全传输增强机制

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电子科技大学学报 2021年第6期50卷 877-882页

作者：张腾月文红唐杰宋欢欢电子科技大学航空航天学院成都611731

终端用户移动是移动网络的一个主要特征。目前,关于物理层安全的研究很少考虑用户移动性对通信安全性能的影响。该文研究了随机移动用户的协同干扰物理层安全机制,推导了随机移动场景中协同干扰下的遍历安全容量,并与静态场景下的协同... 详细信息

终端用户移动是移动网络的一个主要特征。目前,关于物理层安全的研究很少考虑用户移动性对通信安全性能的影响。该文研究了随机移动用户的协同干扰物理层安全机制,推导了随机移动场景中协同干扰下的遍历安全容量,并与静态场景下的协同干扰方案进行了比较。通过数学证明,揭示了具体参数对安全性能的影响。数值结果表明,随机移动场景下协同干扰机制的安全容量和安全能效均有提高,实现了传输安全性的增强。

关键词：协同干扰遍历安全容量物理层安全随机移动模型安全能效

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进口中间品内嵌技术与企业创新

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国际贸易问题 2022年第8期 19-36页

作者：李丹宋换换崔日明辽宁大学金融与贸易学院辽宁大学经济学部

创新是驱动经济高质量发展的第一动力,中间品贸易是技术溢出和扩散的重要载体。本文基于全球生产外包模型,纳入了企业创新行为,揭示了进口中间品内嵌技术对企业创新的影响机理。通过运用世界投入产出(WIOD)数据、中国工业企业数据和企... 详细信息

创新是驱动经济高质量发展的第一动力,中间品贸易是技术溢出和扩散的重要载体。本文基于全球生产外包模型,纳入了企业创新行为,揭示了进口中间品内嵌技术对企业创新的影响机理。通过运用世界投入产出(WIOD)数据、中国工业企业数据和企业专利数据的实证检验发现:(1)进口中间品内嵌技术显著促进了企业创新,且对企业策略性创新的促进作用更大。(2)利润增加效应、生产率提升效应和市场规模扩大效应是进口中间品内嵌技术促进企业创新的主要作用渠道。(3)与来自中高收入经济体的中间品内嵌技术相比,来自高收入经济体的中间品内嵌技术更能促进企业创新。(4)对于外资企业、中高技术、东部和中部地区企业以及处于高竞争环境中的企业,进口中间品内嵌技术的创新效应更为明显。(5)企业吸收能力强化了进口中间品内嵌技术的创新效应,同时技术差距发挥着调节效应。

关键词：进口中间品内嵌技术企业创新吸收能力技术差距

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