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Soil Organic Carbon Stocks as Afected by Tillage Systems in a Double-Cropped Rice Field

Pedosphere 2013年第5期23卷 696-704页

作者： xu shang-qi ZHANG Ming-Yuan ZHANG Hai-Lin CHEN Fu YANG Guang-Li XIAO Xiao-Ping College of Agronomy and Biotechnology China Agricultural University Key Laboratory of Farming System Ministry of Agriculture of China Soil and Fertilizer Institute of Hunan Province

Tillage practices can potentially affect soil organic carbon （SOC） accumulation in agricultural soils. A 4-year experiment was conducted to identify the influence of tillage practices on SOC sequestration in a double-cropped rice （Oryza sativa L.） field in Hunan Province of China. Three tillage treatments, no-till （NT）, conventional plow tillage （PT）, and rotary tillage （RT）, were laid in a randomized complete block design. Concentrations of SOC and bulk density （BD） of the 0-80 cm soil layer were measured, and SOC stocks of the 0-20 and 0-80 cm soil layers were calculated on an equivalent soil mass （ESM） basis and fixed depth （FD） basis. Soil carbon budget （SCB） under different tillage systems were assessed on the basis of emissions of methane （CH4） and CO2 and the amount of carbon （C） removed by the rice harvest. After four years of experiment, the NT treatment sequestrated more SOC than the other treatments. The SOC stocks in the 0-80 cm layer under NT （on an ESM basis） was as high as 129.32 Mg C ha-1, significantly higher than those under PT and RT （P 〈 0.05）. The order of SOC stocks in the 0-80 cm soil layer was NT 〉 PT 〉 RT, and the same order was observed for SCB; however, in the 0-20 cm soil layer, the RT treatment had a higher SOC stock than the PT treatment. Therefore, when comparing SOC stocks, only considering the top 20 cm of soil would lead to an incomplete evaluation for the tillage-induced effects on SOC stocks and SOC sequestrated in the subsoil layers should also be taken into consideration. The estimation of SOC stocks using the ESM instead of FD method would better reflect the actual changes in SOC stocks in the paddy filed, as the FD method amplified the tillage effects on SOC stocks. This study also indicated that NT plus straw retention on the soil surface was a viable option to increase SOC stocks in paddy soils.

关键词： bulk density equivalent soil mass basis soil carbon budget straw retention

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Influence of tectonic preservation conditions on the nanopore structure of shale reservoir: A case study of Wufeng-Longmaxi Formation shale in western Hubei area, south China

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Petroleum Science 2024年第4期21卷 2203-2217页

作者： Meng Xiang shang xu Ya-Ru Wen qi-Yang Gou Bing-Chang Liu National Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) Hubei Key Laboratory of Resources and Eco-environment Geology Hubei Geological Survey Key Laboratory of Tectonics and Petroleum Resources Ministry of Education China University of Geosciences

Tectonism is one of the dominant factors affecting the shale pore structure. However, the control of shale pore structure by tectonic movements is still controversial, which limits the research progress of shale gas accumulation mechanism in the complex tectonic region of southern China. In this study, 34 samples were collected from two exploratory wells located in different tectonic locations. Diverse experiments,e.g., organic geochemistry, XRD analysis, FE-SEM, low-pressure gas adsorption, and high-pressure mercury intrusion, were conducted to fully characterize the shale reservoir. The TOC, Ro, and mineral composition of the shale samples between the two wells are similar, which reflects that the shale samples of the two wells have proximate pores-generating capacity and pores-supporting ***, the pore characteristics of shale samples from two wells are significantly different. Compared with the stabilized zone shale, the porosity, pore volume, and specific surface area of the deformed zone shale were reduced by 60.61%, 64.85%, and 27.81%, respectively. Moreover, the macroscopic and fine pores were reduced by 54.01% and 84.95%, respectively. Fault activity and uplift denudation are not conducive to pore preservation, and the rigid basement of Huangling uplift can promote pore preservation. These three factors are important reasons for controlling the difference in pore structure between two wells shales. We established a conceptual model of shale pores evolution under different tectonic preservation conditions. This study is significant to clarify the scale of shale gas formation and enrichment in complex tectonic regions, and helps in the selection of shale sweet spots.

关键词： Shale gas Pore structure Tectonic preservation conditions Shale gas enrichment mechanism

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Meta分析生物炭对我国农田土壤的増汇减排效应

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安徽师范大学学报（自然科学版） 2024年第5期47卷 422-429页

作者：周静雯向钦佩项金金周子卿李佳琪徐尚起周际海安徽师范大学生态与环境学院皖江流域退化生态系统的恢复与重建省部共建协同创新中心安徽芜湖241002

生物炭作为一种土壤改良剂,对土壤碳汇功能也有着重要影响,在农业和生态修复等领域有很好的应用前景。为系统评估生物炭对农田土壤碳汇和温室效应的影响,本研究采用Meta分析整合了中国知网中204篇(1079个试验组)关于生物炭施入农田土壤... 详细信息

生物炭作为一种土壤改良剂,对土壤碳汇功能也有着重要影响,在农业和生态修复等领域有很好的应用前景。为系统评估生物炭对农田土壤碳汇和温室效应的影响,本研究采用Meta分析整合了中国知网中204篇(1079个试验组)关于生物炭施入农田土壤后土壤有机碳(SOC)及温室气体排放相关指标变化的文献研究结果。结果表明,生物炭施入土壤后显著增强了土壤碳汇功能,SOC及其不同碳组分均显著增加,SOC增幅达47.97%,可溶性有机碳和微生物量碳分别增加17.99%和27.45%,不同粒级团聚体中的有机碳含量增幅介于13.63%~62.41%,其中<0.053mm团聚体的增幅最高。其次,生物炭施入农田土壤后有明显的减排效应,土壤氧化亚氮和甲烷排放量分别降低了23.7%和21.27%,虽然二氧化碳排放量增加了20.28%,但土壤温室气体排放全球增温潜势降低了9.7%,此外,土壤有机碳累积矿化速率也显著降低。总之,生物炭施用可显著促进农田土壤的增汇减排作用,其广泛应用不仅有利于农田土壤的改良,更有利于“碳达峰,碳中和”目标的早日实现。

关键词：生物炭土壤固碳温室气体排放 Meta分析

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Customized heat treatment process enabled excellent mechanical properties in wire arc additively manufactured Mg-RE-Zn-Zr alloys

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International Journal of Extreme Manufacturing 2024年第4期6卷 276-289页

作者： Dong Ma Chunjie xu shang Sui Yuanshen qi Can Guo Zhongming Zhang Jun Tian Fanhong Zeng Sergei Remennik Dan Shechtman School of Materials Science and Engineering Xi'an University of TechnologyXi'anShaanxi 710048People's Republic of China Xi'an Shechtman Nobel Prize New Materials Institute Xi'an 710048People's Republic of China Xi'an Key Laboratory of Advanced Magnesium Alloy Additive Manufacturing and Precision Forming Xi'anShaanxi 710048People's Republic of China Department of Materials Science and Engineering and Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion Guangdong Technion—Israel Institute of TechnologyShantou 515063People's Republic of China MGM Nobel Prize New Materials Co. LtdTongchuan 727100People's Republic of China Department of Materials Science and Engineering Technion-Israel Institute of TechnologyHaifa 32000Israel Center for Nanoscience&Nanotechnology Hebrew University of JerusalemEdmond J.Safra CampusJerusalem 91904Israel

Customized heat treatment is essential for enhancing the mechanical properties of additively manufactured metallic materials,especially for alloys with complex phase constituents and heterogenous ***,the interrelated evolutions of different microstructure features make it difficult to establish optimal heat treatment ***,we proposed a method for customized heat treatment process exploration and establishment to overcome this challenge for such kind of alloys,and a wire arc additively manufactured(WAAM)Mg-Gd-Y-Zn-Zr alloy with layered heterostructure was used for feasibility *** this method,the optimal microstructures(fine grain,controllable amount of long period stacking ordered(LPSO)structure and nano-scaleβ'precipitates)and the corresponding customized heat treatment processes(520°C/30 min+200°C/48 h)were obtained to achieve a good combination of a high strength of 364 MPa and a considerable elongation of 6.2%,which surpassed those of other state-of-the-art WAAM-processed Mg ***,we evidenced that the favorable effect of the undeformed LPSO structures on the mechanical properties was emphasized only when the nano-scaleβ'precipitates were *** is believed that the findings promote the application of magnesium alloy workpieces and help to establish customized heat treatment processes for additively manufactured materials.

关键词： wire arc additive manufacturing heat treatment Mg-RE-Zn-Zr alloys LPSO structure mechanical properties

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Triphenylphosphine-Assisted Exsolution Engineering on Ruddlesden-Popper Perovskites for Promoting Oxygen Evolution

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Energy & Environmental Materials 2024年第4期7卷 433-441页

作者： Juan Bai Jing shang Jun Mei Dongchen qi Ting Liao Ziqi Sun School of Chemistry and Physics Queensland University of Technology Centre for Materials Science Queensland University of Technology School of Materials Science and Engineering Shaanxi University of Science and Technology School of Mechanical Medical and Process Engineering Queensland University of Technology

Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution *** metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas; however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.

关键词： exsolution oxygen evolution perovskite reconstruction Ruddlesden–Popper

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Debris Flow Susceptibility Evaluation in Meizoseismal Region:A Case Study in Jiuzhaigou,China

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Journal of Earth Science 2024年第1期35卷 263-279页

作者： Yongwei Li Linrong xu Yonghui shang Shuyang Chen School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-Speed Railway Construction Technology Central South UniversityChangsha 410075China School of Civil Engineering Central South University of Forestry and TechnologyChangsha 410004China

Jiuzhaigou is situated on a mountain-canyon region and is famous for frequent tectonic *** abundance of loose co-seismic landslides and collapses were produced on gullies after the Jiuzhaigou Earthquake on August 8,2017,which was served as material source for debris flow in later *** flow appears frequently which are seriously endangering the safety of people's lives and *** the earliest debris flow appeared in areas where no case ever reported *** debris flow susceptibility evaluation(DFSE)is used for predicting the areas prone to debris flow,which is urgently required to avoid hazards and help to guide the strategy of preventive ***,this work employs debris flow in Jiuzhaigou to reveal the characteristics of disaster-pregnant environment and to explore the application of machine learning in *** new viewpoints are suggested:(i)Material density factor of debris flow is first adopted in this work,and it is proved to be a critical factor for triggering debris flows by sensitivity analysis method.(ii)Deep neural network and convolutional neural network(CNN)achieve relatively good area under the curve(AUC)values and are 0.021-0.024 higher than traditional machine learning methods.(iii)Watershed units combined with CNNbased model can achieve more accurate,reliable and practical susceptibility *** work provides an idea for prevention of debris flow in mountainous lands.

关键词： machine learning earthquakes debris flow susceptibility convolutional neural network deep neural network watershed unit

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ANALYSIS OF THE IMPLICIT-EXPLICIT ULTRA-WEAK DISCONTINUOUS GALERKIN METHOD FOR CONVECTION-DIFFUSION PROBLEMS

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Journal of Computational Mathematics 2024年第1期42卷 1-23页

作者： Haijin Wang Anping xu qi Tao School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China Beijing Computational Science Research Center Beijing 100193China

In this paper,we first present the optimal error estimates of the semi-discrete ultra-weak discontinuous Galerkin method for solving one-dimensional linear convection-diffusion ***,coupling with a kind of Runge-Kutta type implicit-explicit time discretization which treats the convection term explicitly and the diffusion term implicitly,we analyze the stability and error estimates of the corresponding fully discrete *** fully discrete schemes are proved to be stable if the time-stepτ≤τ0,whereτ0 is a constant independent of the mesh-size ***,by the aid of a special projection and a careful estimate for the convection term,the optimal error estimate is also obtained for the third order fully discrete *** experiments are displayed to verify the theoretical results.

关键词： The ultra-weak discontinuous Galerkin method Convection-diffusion Implicitexplicit time discretization Stability Error estimate

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Experimental quantum state compression from two identical qubits to a qutrit

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 1-5页

作者： qiao xu Lin-Xiang Zhou Tian-Feng Feng shang-Feng qiu Si-Wu Li Wu-Ji Zhang Hui Luo Xiao-qi Zhou State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics Sun Yat-sen UniversityGuangzhou 510000China Hefei National Laboratory Hefei 230088China

In the realm of modern information technology,data compression technology occupies a pivotal *** advancements in quantum information technology,the need to compress large-scale qubits ensembles has become urgent,aiming to reduce the demand on quantum storage ***,existing quantum state compression schemes generally face a limitation:the particles before and after compression must reside in the same dimensional *** specific scenarios,compressing qubits into particles of higher dimensions not only enhances the efficiency of quantum state compression but also further reduces the usage of quantum storage *** we experimentally demonstrated a quantum state compression between particles of different dimensions,successfully compressing two qubits into a single *** average fidelity of the resulting qutrit with the ideal quantum state is *** study may have potential applications in future quantum information,such as increasing quantum communication bandwidth and reducing storage resource consumption in quantum computing.

关键词： quantum state compression quantum information technology optics

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Fault diagnosis method of link control system for gravitational wave detection

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Journal of Systems Engineering and Electronics 2024年第4期35卷 922-931页

作者： GAO Ai xu Shengnan ZHAO Zichen shang Haibin xu Rui School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationBeijing 100081China

To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is *** from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling *** constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault *** simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.

关键词： large scale multi-satellite formation gravitational wave detection laser link monitoring fault diagnosis deep learning

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Simulation study on the security of consensus algorithms in DAG-based distributed ledger

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Frontiers of Computer Science 2024年第3期18卷 171-182页

作者： Shuzhe LI Hongwei xu qiong LI qi HAN Faculty of Computing Harbin Institute of TechnologyHarbin 150001China

Due to the advantages of high volume of transactions and low resource consumption,Directed Acyclic Graph(DAG)-based Distributed Ledger Technology(DLT)has been considered a possible next-generation alternative to ***,the security of the DAG-based system has yet to be comprehensively *** at verifying and evaluating the security of DAG-based DLT,we develop a Multi-Agent based IOTA Simulation platform called *** MAIOTASim,we model honest and malicious nodes and simulate the configurable network environment,including network topology and *** double-spending attack is a particular security issue related to *** perform the security verification of the consensus algorithms under multiple double-spending attack *** simulations show that the consensus algorithms can resist the parasite chain attack and partially resist the splitting attack,but they are ineffective under the large weight *** take the cumulative weight difference of transactions as the evaluation criterion and analyze the effect of different consensus algorithms with parameters under each attack ***,MAIOTASim enables users to perform largescale simulations with multiple nodes and tens of thousands of transactions more efficiently than state-of-the-art ones.

关键词： distributed ledger IOTA Multi-Agent system simulation

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