检索结果-内蒙古大学图书馆

Calibration and Modelling of Vegetation Structure Parameter B for L-Meb Models Over Agricultural Sites

学校读者我要写书评

暂无评论

SSRN

SSRN 2024年

作者： Zhang, Hui Wang, Hongquan Sun, Zhibin Gao, Lun Wang, Yixiang Tong, Cheng Zhu, Luyao Shi, Zhou Institute of Agricultural Remote Sensing and Information Technology Application College of Environmental and Resource Sciences Zhejiang University Hangzhou310058 China Agriculture and Agri-Food Canada Lethbridge Research and Development Centre LethbridgeAB Canada Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems Nanjing Normal University Nanjing210023 China Agroecosystem Sustainability Center Institute for Sustainability Energy and Environment the University of Illinois at Urbana-Champaign UrbanaIL61801 United States State Key Laboratory of Subtropical Silviculture Zhejiang A&F University Hangzhou311300 China Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration of Zhejiang Province Zhejiang A&F University Hangzhou311300 China College of Environment and Resource Sciences Zhejiang A&F University Lin’an Zhejiang311300 China Research Institute for Urban Planning and Sustainability Hangzhou City University Hangzhou310015 China Key Laboratory of Spectroscopy Sensing Ministry of Agriculture Hangzhou310058 China

Passive microwave observations of vegetation water content (VWC) are important to monitor vegetation growth status and terrestrial aboveground biomass. To constrain the L-band Microwave Emission of the Biosphere (L-MEB) model for NASA’s Soil Moisture Active Passive (SMAP) satellite mission, vegetation structure parameter b is often used to estimate VWC from the climatological Normalized Difference Vegetation Index (NDVI). However, little is known about what and how the driving factors impact the parameter b and its modeling due to the lack of quantitative analysis. Based on the Passive Active L-band Sensor (PALS) data from the SMAPVEX16-MB campaign, this study firstly calibrated the parameter b for canola, wheat and soybean. Afterwards, a Random Forest algorithm was employed to model b-values using both h and v polarized observations with the input features screened by correlation analysis and stepwise regression for each vegetation type, the R2 of which exceeds 82%. Considering the poor interpretability of machine learning algorithms, we also employed multivariable-linear regression to quantify their influence on b-values and achieved an R2 exceeding 75%. The results showed all three crop types had an increasing trend in b-values at dual-polarization with their growth, except for wheat which exhibited a decreasing trend at v-polarization. Among the three crops, wheat and soybean indicated sharp changes in b-values, particularly during the late growth stage, while canola exhibited slower changes. The b-values were higher at v-polarization than at h-polarization, except for wheat during the early growth stage and at the end of the late growth stage. The results of multivariable regression with vegetation type as dummy variables (soybean as the control) indicated that crop type significantly affected b values, with canola and wheat exhibiting positive effects on b-values at h-polarization but negative effects at v-polarization. Additionally, we found that VWC, biomass

关键词： Polarization

Fully-charm and -bottom pentaquarks in a Lattice-QCD inspired quark model

学校读者我要写书评

暂无评论

arXiv 2022年

The fully-charm and -bottom pentaquarks, i.e. ccccc¯ and bbbb¯b, with spin-parity quantum numbers JP = 1/2− , 3/2− and 5/2−, are investigated within a Lattice-QCD inspired quark model, which has already successfully described the recently announced fully-charm tetraquark candidate X(6900), and has also predicted several other fully-heavy tetraquarks. A powerful computational technique, based on the Gaussian expansion method combined with a complex-scaling range approach, is employed to predict, and distinguish, bound, resonance and scattering states of the mentioned five-body system. Both baryon-meson and diquark-diquark-antiquark configurations, along with all of their possible color channels are comprehensively considered. Narrow resonances are obtained in each spin-parity channel for the fully-charm and -bottom systems. Moreover, most of them seems to be compact multiquarks whose wave-functions are dominated by either hidden-color baryon-meson or diquark-diquark-antiquark structure, or by the coupling between them. Copyright © 2022, The Authors. All rights reserved.

关键词： Hadrons

First principles investigations of the electronic and magnetic properties of RVO3 (R = Er, Ho, Y, Lu) vanadates

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Jmal, Sohail Ait Balli, Sohail Ait Bouhani, Hamza Mounkachi, Omar AMEEC Team LERMA International University of Rabat Parc Technopolis Rocade de Rabat- Salé 11100 Morocco Complex Systems and Interactions Ecole Centrale Casablanca Morocco Laboratory of Condensed Matter and Interdisciplinary Sciences Department of Physics Faculty of Sciences Mohammed V University in Rabat PO Box 1014 Rabat Morocco Modeling Simulation & Data Analysis Program Mohammed VI Polytechnic University Ben Guerir43150 Morocco

In this paper, we investigate the influence of the rare earth element (R) on the physical properties of RVO3 (R = Er, Ho, Y, Lu). For this purpose, a theoretical work is reported in this study using ab initio method with the intent of enhancing our knowledge of the electronic, and magnetic properties of RVO3 (R = Er, Ho, Y, Lu) compounds. The electronic properties of these materials show the presence of Jahn-Teller effect, with a band gap of approximately 0.58eV, 1.57eV, 1.12eV, 1.28eV, for ErVO3, HoVO3, YVO3, LuVO3, respectively. The magnetic contribution of Ho, Er, and V atoms in HoVO3, and ErVO3 compounds was disentangled using X-ray magnetic circular dichroism (XMCD). The magnetic anisotropies of RVO3 with (R = Er, Ho, Y, Lu) are studied and analyzed using spin orbit coupling. We noticed an easy axis of magnetization along the c-direction with strong magneto-crystalline anisotropy energies for the non-magnetic rare earth elements (R = Lu, Y)VO3. For the magnetic rare earth elements, the easy and hard magnetization direction were found to be along b-axis and c-axis, and a- axis and c-axis for HoVO3, and ErVO3, respectively. This means that instead of the standard magnetization demagnetization process, large thermal effects can be obtained by spinning their single crystals in constant magnetic fields. The exchange coupling between (Ho-V) is also found to be greater than the other exchange interactions in HoVO3. Accordingly, a large conventional magnetocaloric effect could be created in HoVO3, since the Ho Ising moments experience a metamagnetic transition. However, the magnetocaloric effect (MCE) is expected to be lower in ErVO3 due to the weak (Er-V) exchange coupling. © 2022, CC BY.

关键词： Holmium compounds

On Compressible Smooth Viscous Fluids in Slowly Expanding Balls

学校读者我要写书评

暂无评论

Analysis in Theory and Applications 2019年第1期35卷 28-65页

作者： Huicheng Yin Lin Zhang School of Mathematical Sciences Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University

In[17]and[19,20],the global existence and large time behaviors of smooth compressible fluids(including inviscid gases of Euler equations,viscous gases of Navier-Stokes equations,and rarified gases of Boltzmann equation,respectively)have been established in an infinitely expanding ball with a constant expansion *** paper concerns with the viscous fluids in a slowly expanding *** involved analy-sis on the density function and the weighted energy estimates,we show that the fluid in the slowly expanding ball smoothly tends to a vacuum state and there is no appearance of vacuum in any part of the expansive *** present result is a meaningful supplement to the one in[19].

关键词： Compressible Navier-Stokes equations slowly expanding ball weighted energy estimate global existence

Y(4626) in a chiral constituent quark model

学校读者我要写书评

暂无评论

Physical Review D 2020年第5期101卷 054010-054010页

作者： Yue Tan Jialun Ping Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China

Recently, the Belle Collaboration reported a new exotic state Y(4620) with mass at 4625.9 MeV in the positronium annihilation process. Inspired by experiment, we study the tetraquark system cs¯sc¯ with quantum numbers JP=1− in the framework of chiral constituent quark model with the help of Gaussian expansion method. Two structures, diquark-antidiquark and meson-meson, with all possible color and spin configurations are considered. The result shows that no bound state can be formed. To investigate the possible resonance states, the real scaling method is employed. Several resonance states with energies 4354, 4408, 4469, 4497, and 4531 MeV are proposed. Taking into account the errors in calculating the qq¯ mesons, the system errors in the calculation of four-quark system are around 60–100 MeV. The resonance with energy 4531 MeV is possible the candidate of the newly found state Y(4620).

关键词： Hadron-hadron interactions Quark model

Triply heavy baryons in the constituent quark model

学校读者我要写书评

暂无评论

Chinese Physics C 2020年第2期44卷 33-41页

作者： Gang Yang Jialun Ping Pablo GOrtega Jorge Segovia Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua UniversityBeijing 100084China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal UniversityNanjing 210023China Grupo de Física Nuclear and Instituto Universitario de Física Fundamental y Matemáticas(IUFFyM) Universidad de SalamancaE-37008 SalamancaSpain Departamento de Sistemas Físicos Químicos y NaturalesUniversidad Pablo de OlavideE-41013 SevillaSpain

The constituent quark model is used to compute the ground and excited state masses of QQQ baryons containing either c or b *** quark model parameters previously used to describe the properties of charmonium and bottomonium states were used in this *** non-relativistic three-body bound state problem is solved by means of the Gaussian expansion method which provides sufficient accuracy and simplifies the subsequent evaluation of the matrix *** low-lying states with quantum numbers J^P=1/2^±,3/2^±,5/2^±and 7/2^+are *** compare the results with those obtained by the other theoretical *** is a general agreement for the mass of the ground state in each sector of triply heavy ***,the situation is more puzzling for the excited states,and appropriate comments about the most relevant features of our comparison are given.

关键词： Quantum Chromodynamics quark models properties of baryons exotic baryons

Retrofitting coal-fired power plants with biomass co-firing and CCS for net zero carbon emission:A plant-by-plant assessment based on GIS-LCA framework

学校读者我要写书评

暂无评论

Retrofitting coal-fired power plants with biomass co-firing ...

第一届全国碳中和与绿色发展大会

作者： Rui Wang Shiyan Chang Xueqin Cui Jin Li Linwei Ma Amit Kumar Yaoyu Nie Wenjia Cai Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTs International Joint Laboratory on Low Carbon Clean Energy Innovation Tsinghua UniversityBeijingChi State Key Joint Laboratory of Environment Simulation and Pollution Control(SKLESPC) School of Enviro State Key Laboratory of Power Systems Department of Thermal EngineeringTsinghua-BP Clean Energy Cen Department of Mechanical Engineering 10-263 Donadeo Innovation Centre for EngineeringUniversity of Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTs

The targets of limiting global warming levels below 2℃ or even 1.5℃ set by Paris Agreement heavily rely on bioenergy with carbon capture and storage(BECCS),which can remove carbon dioxide in the atmosphere and achieve net zero greenhouse gas(GHG)*** and coal co-firing with CCS is one of BECCS technologies,as well as a pathway to achieve low carbon transformation and upgrading through retrofitting coal power ***,few studies have considered co-firing ratio of biomass to coal based on each specific coal power plant's characteristic information such as location,installed capacity,resources allocation and logistic ***,there is a need to understand whether it is worth retrofitting any individual coal power plant for the benefit of GHG emissions *** is also important to understand which power plant is suitable for retrofit and the associated co-firing *** order to fulfill this gap,this paper develops a framework to solve these questions,which mainly include three ***,biomass resources are assessed at 1-km spatial resolution with the help of RS-GIS ***,by setting biomass collection points and linear program model,resource allocation and supply chain for each power plants are ***,assessing the life-cycle emission for each power *** this study,Hubei Province in China is taken as the research area and study *** main conclusions are as follows:(1)biomass co-firing ratio for each CCS coal power plant to achieve carbon neutral is between 40%~50%;(2)lower co-firing ratio sometimes may obtain better carbon emission reduction benefits;(3)even the same installed capacity power plants should consider differentiated retrofit strategy according to their own *** on the results and analysis above,retrofit suggestions for each power plant are made in the discussion.

关键词： Net zero carbon emission,coal-fired power plant,biomass co-firing GIS-LCA,supply chain,CCS

Investigation of qqqsq¯ pentaquarks in a chiral quark model

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Qin, Liting Tan, Yue Hu, Xiaohuang Ping, Jialun Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

We investigate the pentaquark system qqqsq¯in a framework of chiral quark model. Two structures, (qqq)(sq¯) and (qqs)(qq¯), with all possible color, spin, flavor configurations are considered. The calculations show that there are several possible resonance states, Sigmaπ and NK¯ state with IJP = 012−, Σ∗π with IJP = 032−, Σ∗ρ with IJP = 025 −, ∆K¯ with IJP = 132− and ∆K¯ ∗ with IJP = 152−. Where the NK¯ state with IJP = 012− can be used to explain the Λ(1405), and together with another state Σπ is related to the two-pole structure of the scattering amplitude proposed before. The decay properties of Λ(1520) prevent the assignment of Σ∗π with IJP = 023 − to Λ(1520), although the energy ∼ 1518 MeV of Σ∗π is close to experimental value of Λ(1520). Other resonance states generally have a large width. Copyright © 2020, The Authors. All rights reserved.

关键词： Hadrons

Investigation of Ξc0 in a chiral quark model

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Hu, Xiaohuang Tan, Yue Ping, Jialun Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

Recently, three new states of Ξc0 were observed in the invariant mass spectrum of Λ+c K− by LHCb collaboration. In this work, we use a chiral quark model to investigate these three exited states with the help of Gaussian expansion method both in three-quark structure and in five-quark structure with all possible quantum numbers (formula presented). The calculations shows that the 2S states of Ξc′(2579)0 and Ξc(2645)0 are comparable to experimental results;In addition, the resonance states of five-quark configuration are possible candidates of these new states with negative parity by using the real scaling method and their decay width are also given. Copyright © 2020, The Authors. All rights reserved.

关键词： Elementary particles