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Groundwater discharge drives water quality and greenhouse gas emissions in a tidal wetland

Water Science and Engineering 2022年第2期15卷 141-151页

作者： zhi-lin wang Mahmood Sadat-Noori William Glamore Water Research Laboratory School of Civil&Environmental EngineeringUniversity of New South Wales SydneySydneyNSW 2052Australia

Wetlands play an important role in the global carbon cycle as they can be sources or sinks for greenhouse *** discharge into wetlands can affect the water chemistry and act as a source of dissolved greenhouse gases,including CO_(2)and CH_(4).In this study,surface water quality parameters and CO_(2)and CH_(4)concentrations were evaluated in a tidal wetland(Hunter Wetlands National Park,Australia)using time series ***(^(222)Rn),a natural ground water tracer,was used to investigate the role of groundwater as a pathway for transporting dissolved CO_(2)and CH_(4)into the *** addition,water-to-air CO_(2)and CH_(4)fluxes from the wetland were also *** results showed a high concentration of radon in wetland surface water,indicating the occurrence of ground water *** concentration had a strong negative relationship with water depth with a determination coefficient(R^(2))of 0.7,indicating that tidal pumping was the main driver of groundwater discharge to the *** concentration also showed a positive relationship with CO_(2)and CH_(4)concentrations(R^(2)=0.4 and 0.5,respectively),while the time series data revealed that radon,CO_(2),and CH_(4)concentrations peaked concurrently during low *** implied that groundwater discharge was a source of CO_(2)and CH_(4)to the *** wetland had an average water-to-air CO_(2)flux of 99.1 mmol/(m^(2)·d),twice higher than the global average CO_(2)flux from *** average CH_(4)flux from the wetland was estimated to be 0.3 mmol/(m^(2)d),which is at the higher end of the global CH_(4)flux range for *** results showed that groundwater discharge could be an important,yet unaccounted source of CO_(2)and CH_(4)to tidal *** work has implications for tidal wetland carbon budgets and emphasizes the role of groundwater as a subsurface pathway for carbon transport.

关键词： Groundwater discharge Methane Carbon dioxide Radon Global warming Climate change

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Salinity effect-induced ENSO amplitude modulation in association with the interdecadal Pacific Oscillation

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Journal of Oceanology and Limnology 2024年第4期42卷 1019-1036页

作者： Hai zhi Xiaokun wang Rong-Hua ZHANG Pengfei lin Jifeng QI College of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Laoshan Laboratory Qingdao 266237China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric Physics(IAP)Chinese Academy of SciencesBeijing 100029China Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China

A 110-year ensemble simulation of an ocean general circulation model(OGCM)was analyzed to identify the modulation of salinity interdecadal variability on El Niño-Southern Oscillation(ENSO)amplitude in the tropical Pacific during *** simulating results show that sea surface salinity(SSS)variation in the region exhibits notable and coherent interdecadal variability signal,which is closely associated with the Interdecadal Pacific Oscillation(IPO).As salinity increases or reduces,the SSS modulations on ENSO amplitude during its warm/cold events vary asymmetrically with positive/negative IPO ***,salinity interdecadal variability can enhance or reduce ENSO-related conditions in upper-ocean stratification,contributing noticeably to ENSO *** anomalies associated with the mixed layer depth and barrier layer thickness can modulate ENSO amplitude during positive and negative IPO phases,resulting in the asymmetry of sea surface temperature(SST)anomaly in the tropical *** positive IPO phases,SSS interdecadal variability contributes positively to El Niño amplitude but negatively to La Niña amplitude by enhancing or reducing SSS interannual variability,and vice versa during negative IPO ***,the results indicate that the modulation of the ENSO amplitude by the SSS interdecadal variability is 15%-28%during negative IPO phases and 30%-20%during positive IPO phases,***,the SSS interdecadal variability associated with IPO and its modulation on ENSO amplitude in the tropical Pacific are among factors essentially contributing ENSO diversity.

关键词： El Niño-Southern Oscillation(ENSO)amplitude Interdecadal Pacific Oscillation(IPO) ocean salinity variability tropical Pacific upper-ocean stratification

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Effect of Mo and cold forging deformation on strength and ductility of cobalt-based alloy L605

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Journal of Iron and Steel Research International 2024年第7期31卷 1811-1823页

作者： Zhong-lin wang zhi-hua Gong Quan Li Han-sheng Bao School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014017Inner MongoliaChina Institute of Special Steels Central Iron and Steel Research Institute Co.Ltd.Beijing 100081China

Mo element was added to cobalt-based alloy L605,and cold forging deformation was *** effects of the addition and cold forging deformation on the microstructure and mechanical properties of the alloy were studied by thermodynamic calculation,electron backscatter diffraction,transmission electron microscopy,and X-ray *** stacking fault energy(SFE)of the alloy decreased after the addition,and the formation of stacking faults and intersections were promoted to improve the strength and *** tensile strength of the alloy with Mo increased from 1190 to 1702 MPa after 24%cold deformation,producing significant work *** strengthening mechanism is strain-induced martensitic transformation(SIMT)and deformation *** alloy,combined with Mo and after 24%deformation,had both high strength and ductility in comparison with the original cobalt-based alloy *** is attributed to the lower SFE which caused the increase in stacking fault *** the tensile process,theε-hcp phase was easily generated at the stacking fault to reduce the stress concentration and increase the *** SIMT by adjusting the density of stacking faults can improve the mechanical properties of cobalt-based ***ε-hcp phase,the interaction between deformation twins and dislocations,and the interaction between e-hcp phases during cold forging deformation caused local stress concentration,lowering ductility and toughness.

关键词： Cobalt-based alloy-Stacking fault energy Strain-induced martensitic transformation Deformation twin Cold forging deformation

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Tuning microstructures of TC4 ELI to improve explosion resistance

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Defence Technology（防务技术） 2024年第3期33卷 78-99页

作者： Changle Zhang Yangwei wang lin wang Zixuan Ning Guoju Li Dongping Chen zhi-Wei Yan Yuchen Song Xucai wang School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing 100081China State Key Laboratory of Explosive Science and Technology Beijing Institute of TechnologyBeijing 100081China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Aeronautical Engineering Zhengzhou University of AeronauticsHenan ProvinceZhengzhou 450046China Shanxi Jiangyang Chemical Co. Ltd.Shanxi ProvinceTaiyuan 030041China Shandong Institute of Non-metallic Materials Shandong ProvinceJinan 250031China

A reasonable heat treatment process for TC4 ELI titanium alloy is crucial to tune microstructures to improve its explosion ***,there is limited investigation on tuning microstructures of TC4 ELI to improve explosion ***,the current challenge is quantifying microstructural changes'effects on explosion resistance and incorporating microstructural changes into finite element *** work aims to tune microstructures to improve explosion resistance and elucidate their anti-explosion mechanism,and find a suitable method to incorporate microstructural changes into finite element *** this work,we systematically study the deformation and failure characteristics of TC4 ELI plates with varying microstructures using an air explosion test and LS-DYNA finite element *** Johnson-Cook(JC)constitutive parameters are used to quantify the effects of microstructural changes on explosion resistance and incorporate microstructural changes into finite element *** of the heat treatment,one plate has equiaxed microstructure and the other has bimodal *** convex of the plate after the explosion has a quadratic relationship with the charge mass,and the simulation results demonstrate high reliability,with the error less than 17.5%.Therefore,it is feasible to obtain corresponding JC constitutive parameters based on the differences in microstructures and mechanical properties and characterize the effects of microstructural changes on explosion *** bimodal target exhibits excellent deformation *** response of bimodal microstructure to the shock wave may be more intense under explosive *** well-coordinated structure of the bimodal target enhances its resistance to deformation.

关键词： Microstructure Finite element modelling Parameter optimization Failure characteristics Explosion resistance

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Study of primordial deuterium abundance in Big Bang nucleosynthesis

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Nuclear Science and Techniques 2024年第3期35卷 208-215页

作者： zhi-lin Shen Jian-Jun He Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China

Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early *** these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent *** date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational *** this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium *** found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H ***,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He *** the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.

关键词： Big Bang nucleosynthesis Abundance of deuterium Reaction cross section Reaction rate Monte Carlo method

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Selective Laser Melting of 30CrMnSiA Steel: Laser Energy Density Dependence of Microstructural and Mechanical Properties

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Acta Metallurgica Sinica(English Letters) 2018年第8期31卷 807-814页

作者： lin-zhi wang Wen-Hou Wei Chongqing Key Laboratory of Additive Manufacturing Technology and Systems Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences

Three-dimensional parts of the 30 CrMnSiA steel were successfully fabricated using selective laser melting（SLM）. The microstructures and mechanical properties of the SLM-processed 30 CrMnSiA samples were investigated by scanning electron microscope and transmission electron microscopy. The results indicate that the microstructures of the 30 CrMnSiA samples consist mainly of lath martensite and acicular martensite. The value of the surface roughness decreases with increasing laser energy density（LED） before it reaches a minimum and then increases with further increasing LED. The relative density, microhardness and ultimate tensile strength of the SLM-processed samples initially increase and then decrease with increasing LED. By taking the relative density, surface roughness, microhardness and ultimate tensile strength into account, the optimized LED should be in the range of 46.15–51.28 J mm^（-3） for the SLM-processed30 CrMnSiA alloys. In addition, the differences in the microstructures and mechanical properties between the conventionally wrought 30 CrMnSiA sample and SLM-processed 30 CrMnSiA samples were also studied.

关键词： 30CrMnSiA Selective laser melting Laser energy density Microstructure Mechanical properties

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Optimization Design of the Multi-Layer Cross-Sectional Layout of An Umbilical Based on the GA-GLM

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China Ocean Engineering 2024年第2期38卷 247-254页

作者： YANG zhi-xun YIN Xu FAN zhi-rui YAN Jun LU Yu-cheng SU Qi MAO Yandong wang Hua-lin Institute of marine machinery College of Mechanical and Electrical EngineeringHarbin Engineering UniversityHarbin 150001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDepartment of Engineering MechanicsDalian University of TechnologyDalian 116024China Ningbo Institube of Dalian University of Technology Ningbo 315040China

Marine umbilical is one of the key equipment for subsea oil and gas exploitation,which is usually integrated by a great number of different functional components with *** layout of these components directly affects manufacturing,operation and storage performances of the *** the multi-layer cross-sectional layout design of the umbilical,a quantifiable multi-objective optimization model is established according to the operation and storage *** the manufacturing factors,the multi-layering strategy based on contact point identification is introduced for a great number of functional ***,the GA-GLM global optimization algorithm is proposed combining the genetic algorithm and the generalized multiplier method,and the selection operator of the genetic algorithm is improved based on the steepest descent *** algorithm is used to find the optimal solution in the global space,which can converge from any initial layout to the feasible layout *** feasible layout solution is taken as the initial value of the generalized multiplier method for fast and accurate ***,taking umbilicals with a great number of components as examples,the results show that the cross-sectional performance of the umbilical obtained by optimization algorithm is better and the solution efficiency is ***,the multi-layering strategy is effective and *** design method proposed in this paper can quickly obtain the optimal multi-layer cross-sectional layout,which replaces the manual design,and provides useful reference and guidance for the umbilical industry.

关键词： umbilical cross-sectional layout multi-layers GA-GLM optimization

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Effects of the types of overlap on the mechanical properties of FSSW welded AZ series magnesium alloy joints

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International Journal of Minerals,Metallurgy and Materials 2012年第3期19卷 231-235页

作者： Dan wang Jun Shen lin-zhi wang School of Materials Science and Engineering Chongqing UniversityChongqing 400044China

The effects of the types of overlap on the mechanical properties of the friction stir spot welding （FSSW） welded AZ series magnesium alloy joints were investigated by microstructural observations, microhardness tests, and tensile tests. The results show that the microstructure of the stir zone adjacent to the periphery of the rotating pin is mainly composed of the upper sheet. The average distance D between the longitudinal segment of the curved interface and the keyhole periphery, the tensile shear force, and the microhardness of the stir zone of the FSSW welded AZ61 alloy joint are the highest in all samples. During FSSW of AZ31 and AZ61 dissimilar magnesium alloys, the irregular deformation of the longitudinal segment of the curved interface appears, while the microhardness of the stir zone is higher when AZ61 alloy is the upper sheet. Moreover, the microhardness of the stir zone increases initially and then decreases sharply in the longitudinal test position.

关键词： magnesium alloys friction stir welding microstructure microhardness tensile properties

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Oxidation resistant low-alloyed Ti alloys with good ductility

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Rare Metals 2024年第8期43卷 3921-3936页

作者： Meng Li Zhang-zhi Shi Jun-Yi Xu Fu-zhi Dai Xiang-Min Li Zi-lin Li Lu-Ning wang Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advance Metals and MaterialsSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijingBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Oxidation resistance enhancement of pure Ti often comes at the cost of reduced ductility,which is frequently the problem through alloying with sole Al,Si,W,Mo and *** overcome the short coming of single element alloying,this paper proposes a multi-element low-alloying strategy to take advantage of synergistic effects and resolve the conflict between oxidation resistance and *** demonstrates that the addition of a small quantity of Ta(0.51wt%)can boost both oxidation resistance and ductility in comparison to pure ***,the combined addition of a small amount(0.54 wt%)of Ta,Nb and Si not only preserves good ductility of pure Ti,but also reduces mass gains to 14%-67%of pure Ti during 100 h oxidation at 650-850℃in *** indicates even better oxidation resistance than that obtained through the use of Ta,Nb,or Nb+Ta *** Ta+Nb+Si alloying creates an oxide layer that is less porous and more resistant to stratification and ***,a 3-μm N-rich layer can form in the Ti substrate beneath the oxide scale,in which phase transformation generates coherent Ti_(2)N with(0001)_(Ti)as the habit plane,with N atoms prefers to diffuse along■than along[0001]_(Ti).The completely transformed Ti_(2)N region or partially transformed Ti+Ti_(2)N region can effectively impede oxygen ***,the multielement low-alloying strategy is promising for enhancing both oxidation resistance and mechanical properties of metallic materials in the future.

关键词： Ti alloys Multi-element Co-alloying Oxidation resistance Mechanical properties

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Super-resolution diffractive neural network for alloptical direction of arrival estimation beyond diffraction limits

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Light(Science & Applications) 2024年第8期13卷 1602-1614页

作者： Sheng Gao Hang Chen Yichen wang Zhengyang Duan Haiou Zhang zhi Sun Yuan Shen Xing lin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Wireless sensing of the wave propagation direction from radio sources lays the foundation for communication,radar,navigation,***,the existing signal processing paradigm for the direction of arrival estimation requires the radio frequency electronic circuit to demodulate and sample the multichannel baseband signals followed by a complicated computing process,which places the fundamental limit on its sensing speed and energy ***,we propose the super-resolution diffractive neural networks(S-DNN)to process electromagnetic(EM)waves directly for the DOA estimation at the speed of *** multilayer meta-structures of S-DNN generate super-oscillatory angular responses in local angular regions that can perform the all-optical DOA estimation with angular resolutions beyond the diffraction *** spatial-temporal multiplexing of passive and reconfigurable S-DNNs is utilized to achieve high-resolution DOA estimation over a wide field of *** S-DNN is validated for the DOA estimation of multiple radio sources over 5 GHz frequency bandwidth with estimation latency over two to four orders of magnitude lower than the state-of-the-art commercial devices in *** results achieve the angular resolution over an order of magnitude,experimentally demonstrated with four times,higher than diffraction-limited *** also apply S-DNN’s edge computing capability,assisted by reconfigurable intelligent surfaces,for extremely low-latency integrated sensing and communication with low power *** work is a significant step towards utilizing photonic computing processors to facilitate various wireless sensing and communication tasks with advantages in both computing paradigms and performance over electronic computing.

关键词： beyond optical network

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