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Novel time-frequency differential space-time modulation for multi-antenna OFDM systems

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Journal of Systems Engineering and Electronics 2006年第1期17卷 54-58页

作者： Tian Jifeng Jiang Haining Song wentao luo Hanwen Xu Youyun Dept. of Electronic Engineering Shanghai Jiaotong Univ. Shanghai 200030 P.R. China

Differential space-time （DST） modulation has been proposed recently for multiple-antenna systems over Rayleigh fading channels, where neither the transmitter nor the receiver knows the fading coefficients. Among existing schemes, differential modulation is always performed in the time domain and suffers performance degradations in frequency-selective fading channels. In order to combat the fast time and frequency-selective fading, a novel time-frequency differential space-time （TF-DST） modulation scheme, which adopts differential modulation in both time and frequency domains, is proposed for multi-antenna orthogonal frequency division multiplexing （OFDM） system. A corresponding suboptimal yet low-complexity non-coherent detection approach is also proposed. Simulation results demonstrate that the proposed system is robust for time and frequency-selective Rayleigh fading channels.

关键词： differential space-time modulation MIMO OFDM time-varying channel.

Responses and sensitivity of N, P and mobile carbohydrates of dominant species to increased water, N and P availability in semi- arid grasslands in northern China

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Journal of Plant Ecology 2017年第3期10卷 486-496页

作者： Xue Wang Zhuwen Xu Caifeng Yan wentao luo Ruzhen Wang Xingguo Han Yong Jiang Mai-He Li Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesNo.72 Wenhua RoadShenhe DistrictShenyang 110016China College of Resources and Environment University of Chinese Academy of SciencesNo.19A Yuquan RoadShijingshan DistrictBeijing 100049China Forest dynamics Swiss Federal Research Institute WSlZuercherstrasse 111CH-8903 BirmensdorfSwitzerland

Aims We aimed to improve the understanding of the carbon and nutri-ent physiological responses and adaptation of semi-arid grassland plants to environmental *** We investigated plant leaf non-structural carbohydrate(NSC=solu-ble sugars+starch),nitrogen(N)and phosphorus(P)levels in an Inner Mongolian semi-arid grassland community treated with water,N and P additions for 8 *** dominant grasses(Agropyron cris-tatum(L.)Gaertn.,Stipa krylovii Roshev.)and two forbs(Artemisia frigida Willd.,Potentilla bifurca L.)were *** Findings Water addition decreased plant leaf N and P concentrations,whereas N and P addition increased them,indicating that the semi-arid grassland studied suffers from a shortage of N and P *** N and P addition decreased the levels of soluble sugars,starch and thus also NSC in plant leaves,which may be attributed to(i)increased carbohydrate consumption associated with a higher growth rate,and(ii)a dilution effect of greater plant size under N and P *** addition tended to increase the leaf NSC levels both in the grasses(+9.2%)and forbs(+0.6%only),which may be a result of increased photosynthesis of plants with increased water *** conditions of ambient and increased water supply in the present study,N addition resulted in an N/P ratio of>16 in the grasses but a significantly lower N/P ratio of<11 in the forb *** finding implies that growth of the two grass spe-cies will be limited mainly by P availability but the forbs will still be mainly limited by N supply if N deposition,alone or in combination with summer precipitation,continues to increase as predicted in Inner Mongolia.

关键词： climate change non-structural carbohydrates perennial grasses perennial forbs steppe

Variations in leaf carbon isotope composition along an arid and semi-arid grassland transect in northern China

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Journal of Plant Ecology 2016年第5期9卷 576-585页

作者： Chao Wang Dongwei Liu wentao luo Yunting Fang Xiaobo Wang Xiaotao Lü Yong Jiang Xingguo Han Edith Bai Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110164China

Aims We aimed to quantify the variation of leafδ^(13)C along an arid and semi-arid grassland transect in northern *** also evaluated the effects of environmental factors(***,temperature and altitude)on the spatial variation of leafδ^(13)C in northern grasslands and Tibetan Plateau,*** We sampled leaves of plant species belonging to three herb genera(Stipa spp.,Leymus *** Cleistogenes spp.)and three shrub genera(Caragana spp.,Reaumuria *** Nitraria spp.)for carbon isotope analysis from 50 locations along a 3200-km arid and semiarid grassland transect in northern ***δ^(13)C data in Tibetan Plateau and northern grasslands in China were also compiled from studies in *** Findings Along the transect,leafδ^(13)C for C_(3)plants ranged from−28.0‰to−23.3‰,and from−16.3‰to−13.8‰for C_(4)plant Cleistogenes spp..The change in leafδ^(13)C ranged from−0.26‰to−3.51‰with every 100 mm increase of annual precipitation,and leafδ^(13)C of shrubs(Nitraria spp.,Reaumuria *** Caragana spp.)responded more markedly to climatic factors(precipitation and temperature)than that of herbs(Stipa spp.,Leymus *** Cleistogenes spp.),indicating higher sensitivity of shrubδ^(13)C to climatic *** most important factor regulating spatial variations of leafδ^(13)C in Tibetan Plateau was altitude,while it was precipitation in northern *** results suggested that shrubs are more adapted to increasing drought in arid and semi-arid *** of environmental factors on leafδ^(13)C depended on the most limiting factors in arid grassland(precipitation)and Tibetan grasslands(atmospheric CO_(2)concentration).

关键词： carbon isotope water use efficiency plant life-form rainfall gradient climate change

Primordial black hole mass functions as a probe of cosmic origin

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 164-171页

作者： Yi-Fu Cai Chengfeng Tang Geyu Mo Sheng-Feng Yan Chao Chen Xiao-Han Ma Bo Wang wentao luo Damien A.Easson Antonino Marcianò Deep Space Exploration Laboratory/School of Physical Sciences University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory for Researches in Galaxies and Cosmology/Department of Astronomy School of Astronomy and Space ScienceUniversity of Science and Technology of ChinaHefei 230026China Istituto Nazionale di Fisica Nucleare(INFN) Sezione di MilanoMilano 20146Italy DiSAT Universitàdegli Studi dell'InsubriaComo 22100Italy Jockey Club Institute for Advanced Study The Hong Kong University of Science and TechnologyHong KongChina Department of Physics Arizona State UniversityTempe 85287-1504USA Department of Physics&Center for Field Theory and Particle Physics Fudan UniversityShanghai 200433China Laboratori Nazionali di Frascati INFN Via Enrico Fermi 541 Frascati(Roma)00044Italy INFN sezione Roma Tor Vergata Rome I-00133Italy School of Physics University of Electronic Science and Technology of ChinaChengdu11731China

We discuss a novel window to probe the origin of our universe via the mass functions of primordial black holes(PBHs).The mass functions of PBHs are simply estimated using the conventional Press-Schechter formalism for two paradigms of cosmic origin,including inflationaryΛCDM and bounce *** standard inflationaryΛCDM model cannot generate an appreciable number of massive PBHs;however,non-trivial inflation models with blue-tilted power spectra at small scales and matter bounce cosmology provide formation mechanisms for heavy PBHs,which in turn,may seed the observed supermassive black holes(SMBHs).By fitting the SMBH mass functions at high redshift(z~6)derived from Sloan Digital Sky Survey(SDSS)and Canada-France High-z Quasar Survey(CFHQS)quasars,for two paradigms of cosmic origin,we derive constraints on the PBH density fraction fPBHat z~6 and the characteristic mass M_(★),with the prior assumption that all SMBHs stem from *** demonstrate that this newly proposed procedure,relying on astronomical measurements that utilize deep-field surveys of SMBHs at high redshift,can be used to constrain models of cosmic ***,although not the main focus of this paper,we evolve the mass function from z~6 to z~0 through an assumption of 3×10^(8)-year Eddington’s accretion,and give a rough estimation of fPBHat z~0.

关键词： origin cosmic massive

Unexpected Diversity in Ecosystem Nutrient Responses to Experimental Drought in Temperate Grasslands

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Phyton-International Journal of Experimental Botany 2024年第4期93卷 831-841页

作者： Biying Qiu Niwu Te Lin Song Yuan Shi Chuan Qiu Xiaoan Zuo Qiang Yu Jianqiang Qian Zhengwen Wang Honghui Wu wentao luo School of Life Sciences Hebei UniversityBaoding071002China Liaoning Northwest Grassland Ecosystem National Observation and Research Station Erguna Forest-Steppe Ecotone Research StationInstitute of Applied EcologyChinese Academy of SciencesShenyang110164China Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou730030China School of Grassland Science Beijing Forestry UniversityBeijing100083China College of Forestry Henan Agricultural UniversityZhengzhou450002China State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing100081China Key Laboratory of Arable Land Quality Monitoring and Evaluation Ministry of Agriculture and Rural AffairsInstitute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing100081China

The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a significantuncertainty to synthesis and site comparisons. We investigated the responses of vegetation and soil nutrientsto drought using a network experiment of temperate grasslands in Northern China. Drought treatment (66%reduction in growing season precipitation) was imposed by erecting rainout shelters, respectively, at the driest,intermediate, and wettest sites. We found that vegetation nutrient concentrations increased but soil nutrient concentrationsdecreased along the aridity gradient. Differential responses were observed under experimentaldrought among the three grassland sites. Specifically, the experimental drought did not change vegetation andsoil nutrient status at the driest site, while strongly reduced vegetation but increased soil nutrient concentrationsat the site with intermediate precipitation. On the contrary, experimental drought increased vegetation N concentrationsbut did not change vegetation P and soil nutrient concentrations at the wettest site. In general, the differentialeffects of drought on ecosystem nutrients were observed between manipulative and observationalexperiments as well as between sites. Our research findings suggest that conducting large-scale, consistent, andcontrolled network experiments is essential to accurately evaluate the effects of global climate change on terrestrialecosystem bio-geochemistry.

关键词： Climate change drought experiment precipitation nutrient cycles

Product Knowledge Representation and Integration Technology in Web-based Collaborative Design

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武汉理工大学学报 2006年第S1期28卷 220-227页

作者： HAO wentao,TIAN Ling,luo Wei,TONG Bingshu (Department of Precision Instruments and Mechanology,Tsinghua University,Beijing 100084,China) Department of Precision Instruments and Mechanology Tsinghua UniversityBeijing 100084China

Because of the complexity of modern product design,the web-based collaborative product design aroused considerable attention of manufacturers in the last few years with the development of Internet technology. But it is still hardly achievable due to the difficulty to share product knowledge from different designers and systems. In this paper,we firstly create an ontology-based product model,which consists of PPR (Product,Process and Resource) concept models and PPR characteristic models,to describe product knowledge. Afterwards,how to represent the model in XML is discussed in detail. Then the mechanism of product knowledge collection and integration from different application systems based on interface agents is introduced. At last,a web-based open-architecture product knowledge integrating and sharing prototype system AD-HUB is developed. An example is also given and it shows that the theory discussed in this paper is efficient to represent and integrate product knowledge in web-based collaborative design processes.

关键词： collaborative design knowledge representation ontology interface agent

基于WS3P分析的发展自由贸易区可行性、阻碍、对策研究——以连云港建设自贸区为例

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经济问题探索 2019年第12期 146-152页

作者：罗文涛清华大学机械工程系

自由贸易区是对外开放的最深层次,在繁荣经济发展、降低金融风险、带动产业升级、形成生态发展圈方面发挥重要职能。连云港市拥有与上海相同条件的海港优势,承担着国家多个国际发展战略的重要职能。关于在连云港设置自由贸易区可行性的... 详细信息

自由贸易区是对外开放的最深层次,在繁荣经济发展、降低金融风险、带动产业升级、形成生态发展圈方面发挥重要职能。连云港市拥有与上海相同条件的海港优势,承担着国家多个国际发展战略的重要职能。关于在连云港设置自由贸易区可行性的研究未有比较系统、全面的梳理,本文以连云港为例从硬件(W)、软件(S)、制度(P)、个性(P)、平台(P)五个维度出发分析发展自由贸易区的可行性,总结在海港城市发展自由贸易区的阻碍以及相应对策,旨在为自由贸易区的理论研究和实践应用提供参考。

关键词：五维分析自由贸易试验区连云港城市

Effects of plant intraspecific variation on the prediction of C_(3)/C_(4)vegetation ratio from carbon isotope composition of topsoil organic matter across grasslands

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Journal of Plant Ecology 2021年第4期14卷 628-637页

作者： wentao luo Xiaoguang Wang Karl Auerswald Zhengwen Wang Michael I.Bird Christopher J.Still Xiao-Tao Lv Xingguo Han Erguna Forest-Steppe Ecotone Research Station Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China College of Environment and Resources Dalian Minzu UniversityDalian 116600China Technische Universität München Lehrstuhl für GrünlandlehreAlte Akademie 1285350 Freising-WeihenstephanGermany College of Science and Engineering and ARC Centre of Excellence for Australian Biodiversity and Heritage James Cook UniversityCairnsQueensland 4870Australia Department of Forest Ecosystems and Society Oregon State UniversityCorvallisORUSA State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China

Aims Understanding the patterns and drivers of carbon isotope discrimination(13Δ)in C_(3)and C_(4)functional groups is critical for predicting C_(3)/C_(4)vegetation ratio from the isotopic composition of soil organic *** this study,we aimed to evaluate how intraspecific variation will modify functional group-level 13Δvalues and the associated prediction of C_(3)/C_(4)vegetation *** We investigated 13Δof 726 individual plants(96 species;C_(3)and C_(4)functional groups)and topsoil organic matter in 26 grassland communities along an aridity gradient in northern *** fraction of C_(4)contribution was calculated with mixing models that considered:(i)both intra-and interspecific effects on the 13Δvalues of C_(3)and C_(4)functional groups;(ii)only interspecific effects;or(iii)none of these *** Findings We found divergent responses of plant 13Δat the intraspecific level to the changes of aridity across the *** 13Δof both C_(3)and C_(4)functional groups was negatively correlated with an aridity index,with higher sensitivity for C_(3)than for C_(4)functional *** 13Δvariation played a key role in driving the total 13Δvariations of C_(3)*** such intraspecific effect in mixing models led to a greatly increased fraction of C_(4)contribution to soil organic carbon.A correction for the effects of intraspecific variation is therefore essential for correctly inferring C_(3)/C_(4)vegetation ratio in the *** findings provide basic information for the reconstruction of past vegetation change from bulk materials in arid and semiarid biomes.

关键词： arid and semiarid grasslands interspecific variation intraspecific variation soil organic matter two-member mixing models vegetation ratio

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谨慎评价围栏在我国草地治理体系中的作用

内蒙古大学学报（自然科学版） 2020年第5期51卷 554-560页

作者：李昂雒文涛中国科学院植物研究所植被与环境变化国家重点实验室北京100093 中国科学院沈阳应用生态研究所额尔古纳森林草原过渡带生态系统研究站沈阳110016

草地围栏诱发的生态负面后果引起了公众的广泛关注。草地围栏具有生产、生态和标志产权等多重功能。在生态功能外,草地围栏更直接支撑了当前草地承包使用权制度,促进草地使用权的交易流转,进而实现草地的抗灾救济等社会保障功能。因此,... 详细信息

草地围栏诱发的生态负面后果引起了公众的广泛关注。草地围栏具有生产、生态和标志产权等多重功能。在生态功能外,草地围栏更直接支撑了当前草地承包使用权制度,促进草地使用权的交易流转,进而实现草地的抗灾救济等社会保障功能。因此,在草地产权制度尚未发生重大转变之前,不宜全面废除围栏。当前需要对现有围栏进行生态优化,并探索替代围栏的新型草地治理模式。待条件全面成熟后,方可进行根本性的围栏政策调整。

关键词：草地围栏产权改革社会-生态复杂系统草地管理政策可持续治理