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Grain refinement of Mg-Ca alloys by native MgO particles

Journal of Magnesium and Alloys 2024年第3期12卷 980-996页

作者： shihao wang Yun wang Quentin M.Ramasse Zhongyun Fan Super STEM Laboratory SciTech Daresbury CampusDaresbury WA44ADUK School of Chemical and Process Engineering University of LeedsLeeds LS29JTUK BCAST Brunel University LondonUxbridgeMiddlesex UB83PHUK

In Mg-Ca alloys the grain refining mechanism,in particular regarding the role of nucleant substrates,remains the object of *** native MgO is being recognised as a nucleating substrate accounting for grain refinement of Mg alloys,the possible interactions of MgO with alloying elements that may alter the nucleation potency have not been elucidated ***,we design casting experiments of Mg-xCa alloys varied qualitatively in number density of native MgO,which are then comprehensively studied by advanced electron *** results show that grain refinement is enhanced as the particle number density of MgO *** native MgO particles are modified by interfacial layers due to the co-segregation of Ca and N solute atoms at the MgO/Mg *** aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy,we reveal the nature of these Ca/N interfacial layers at the atomic *** of the crystallographic termination of MgO,Ca and N co-segregate at the MgO/Mg interface and occupy Mg and O sites,respectively,forming an interfacial structure of a few atomic *** interfacial structure is slightly expanded,less ordered and defective compared to the MgO matrix due to compositional deviations,whereby the MgO substrate is altered as a poorer template to nucleate Mg *** solidification in a TP-1 mould,the impotent MgO particles account for the grain refining mechanism,where they are suggested to participate into nucleation and grain initiation processes in an explosive *** work not only reveals the atomic engineering of a substrate through interfacial segregation but also demonstrates the effectiveness of a strategy whereby native MgO particles can be harnessed for grain refinement in Mg-Ca alloys.

关键词： Mg-Ca alloy Grain refinement MgO Interfacial segregation STEM/EELS Solidification.

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A calibration method of external parameters of 2D laser in rotary 3D scanning

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Optoelectronics Letters 2022年第12期18卷 730-736页

作者： wang shihao QIAO Zhifeng HUANG Jiahao Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin300384China

Aiming at the problem of external parameter calibration in the combined rotating three-dimensional(3D) scanning process of laser radar and turntable, a fast 3D data scanning and accurate equipment calibration method suitable for industrial application scenarios is proposed. The coordinates of the center of the circle in the laser radar coordinate system are obtained by fitting the coordinates of the center of the circle with the scanning arc. Through the standard size and rotation angle of the target ball, the coordinates of the ball center in the turntable coordinate system are obtained. The rotation parameter R and the translation parameter T of the minimum value of the data set conversion error function in the two coordinate systems are calculated. The experimental results show that the error between the converted data and the actual data is within 0.1 mm, which meets the actual work requirements. This calibration method has the advantages of high accuracy and strong robustness.

关键词： coordinate rotation parameter

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An accurate pose measurement method of workpiece based on rapid extraction of local feature points

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Optoelectronics Letters 2022年第6期18卷 372-377页

作者： ZHANG Jiangtao QIAO Zhifeng wang shihao Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China

Ceramic sanitary products with complex curved surfaces are generally fragile and difficult to *** the industrial robot is utilized to realize the automatic grinding of such products,the precise positioning of the product is required *** this paper,an accurate pose measurement system for complex curved surface parts is designed by point cloud registration *** order to improve the stability of the system,this paper combines the advantages of normal vector features and fast point feature histogram(FPFH)features,and proposes a point cloud registration algorithm based on the rapid extraction of local feature *** results verify that the improved algorithm has improved both efficiency and accuracy,and the system can effectively achieve accurate positioning of products.

关键词： robot system curved

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Morphologically templated nucleation of primary Si on AlP in hypereutectic Al-Si alloys

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Journal of Materials Science & Technology 2022年第5期100卷 36-45页

作者： Xiangzhen Zhu shihao wang Xixi Dong Xiangfa Liu Shouxun Ji Brunel Centre for Advanced Solidification Technology(BCAST) Brunel University LondonUxbridgeMiddlesex UB83PHUnited Kingdom Key Laboratory for Liquid-Solid Structural Evolution&Processing of Materials Ministry of EducationShandong UniversityJinan 250061China

AlP has been widely used as an effective heterogenous nucleus for primary Si phase in hypereutectic AlSi alloys,but the morphological correlation between AlP and primary Si is still *** the present work,the morphologies of AlP crystals were studied comprehensively by experimental observation and theorical *** is found that AlP collected from an Al-0.03 P melt could be divided into two categories:spinel twin crystals and non-twin *** the nucleation process,these two kinds of AlP crystals triggered morphologically templated nucleation of primary Si phase,resulting in the formation of hexagonal primary Si twin and octahedral non-twin crystals,*** such,the percentage of primary Si twin crystals in the experimental Al-18 Si alloy was also increased obviously after the morphologically templated nucleation via Al *** morphologically templated nucleation also eliminated the dendritic growth of primary Si phase and the formation of hopper structures inside primary Si,forcing primary Si to maintain to be faceted solid crystals through layer-by-layer growing *** insight into morphologically templated nucleation offers a new view in understanding the mechanism of heterogeneous nucleation of primary Si phase on AlP nuclei.

关键词： Aluminium alloys Solidification Nucleation Primary Si,Grain refinement Morphology

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Comparative evaluation of SPE methods for biotoxicity assessment of water and wastewater:Linkage between chemical extracting efficiency and biotoxicity outcome

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Journal of Environmental Sciences 2024年第8期142卷 33-42页

作者： Jiawei Zhou shihao wang Xiwei He Hongqiang Ren Xu-Xiang Zhang State Key Laboratory of Pollution Control and Resource Reuse School of EnvironmentNanjing UniversityNanjing 210023China

Biotoxicity assessment results of environmental waters largely depend on the sample extraction protocols that enrich pollutants to meet the effect-trigger thresholds of ***,more chemical mixture does not necessarily translate to higher combined ***,there is a need to establish the link between chemical extracting efficiency and biotoxicity outcome to standardize extraction methods for biotoxicity assessment of environmental *** study compares the performance of five different extraction phases in solid phase extraction(SPE),namely HLB,HLB+Coconut,C18 cartridge,C18 disk and Strata-X,and evaluated their chemical extracting efficiencies and biotoxicity *** quantitatively assessed cytotoxicity,acute toxicity,genotoxicity,estrogenic activity,and neurotoxicity of the extracts using in vitro bioassays and characterized the chemical extracting efficiencies of the SPE methods through chemical recoveries of 23 model compounds with different polarities and total organic *** Pareto ranking,we identified HLB+Coconut as the optimal SPE method,which exhibited the highest level of water sample biotoxicity and recovered the most chemicals in water *** found that the biotoxicity outcomes of the extracted water samples significantly and positively correlated with the chemical extracting efficiencies of the SPE ***,we observed synchronous changing patterns in biotoxicity outcome and chemical extracting efficiencies in response to increasing sample volumes per cartridge(SVPC)during *** findings underscore that higher chemical extracting efficiency of SPE corresponds to higher biotoxicity outcome of environmental water samples,providing a scientific basis for standardization of SPE methods for adequate assessment of biotoxicities of environmental waters.

关键词： Biotoxicity Chemical recovery Solid phase extraction Surface water Wastewater

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A new die-cast magnesium alloy for applications at higher elevated temperatures of 200-300℃

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Journal of Magnesium and Alloys 2021年第1期9卷 90-101页

作者： Xixi Dong Lingyun Feng shihao wang Eric A.Nyberg Shouxun Ji Brunel Centre for Advanced Solidification Technology(BCAST) Brunel University LondonUxbridge UB83PHUnited Kingdom Tungsten Parts Wyoming LaramieWY 82072USA

The development of lightweight magnesium(Mg)alloys capable of operating at elevated temperatures of 200-300℃and the ability of using high pressure die casting for high-volume manufacturing are the most advanced developments in manufacturing critical parts for internal combustion engines used in power *** we report the microstructure and mechanical properties of a newly developed die-cast Mg-RE(La,Ce,Nd,Gd)-Al alloy capable of working at higher elevated temperatures of 200-300℃.The new alloy delivers the yield strength of 94 MPa at 300℃,which demonstrates a 42%increase over the benchmark AE44 high temperature die-cast Mg *** new alloy also has good stiffness at elevated temperatures with its modulus only decreasing linearly by 13%from room temperature up to 300℃.Thermal analysis shows a minor peak at 364.7℃in the specific heat curve of the new alloy,indicating a good phase stability of the alloy up to 300℃.Nd and Gd have more affinity to Al for the formation of the minority of divorced Al-RE(Nd,Gd)based compounds,and the stable Al-poor Mg_(12)RE(La_(0.22)Ce_(0.13)Nd_(0.31)Gd_(0.31))Zn_(0.39)Al_(0.13)compound acts as the continuous inter-dendritic network,which contribute to the high mechanical performance and stability of the new die-cast Mg alloy at 200-300℃.

关键词： Magnesium alloys High pressure die casting Elevated temperatures Microstructure Mechanical properties

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A tight sandstone multi-physical hydraulic fractures simulator study and its field application

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Petroleum 2020年第2期6卷 198-205页

作者： Yonghong wang Binshan Ju shihao wang Zhenzhou Yang Qing Liu School of Energy Resource China University of GeoscienceBeijingChina CNPC Engineering Technology R&D Company Limited(CPET) China Petroleum Engineering Department Colorado School of MinesGoldenCO80401USA

During the past years,the recovery of unconventional gas formation has attracted lots of attention and achieved huge *** produce gas from the low-permeability unconventional formations,hydraulic fracturing technology is essential and *** this paper,we present the development of a three-dimensional thermalhydraulic-mechanical numerical simulator for the simulation of hydraulic fracturing operations in tight sandstone *** simulator is based on integrated finite difference(IFD)*** this method,the simulation domain is subdivided into sub domains and the governing equations are integrated over a sub domain with flux terms expressed as an integral over the sub domain boundary using the divergence *** simulator conducts coupled thermal-hydraulic-mechanical simulation of the initiation and extension of hydraulic *** also calculates the mass/heat transport of injected hydraulic fluids as well as *** simulator is able to handle anisotropic formations with multiple *** simulator has been validated by comparing with an analytical solution as well as Ribeiro and Sharma *** model can simulate fracture spacing effect on fracture profile when combining IFD with Discontinuous Displacement Method(DDM).

关键词： Tight sandstone Hydraulic fracture simulator Integrated finite difference discretization Stress contrast

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Waste to treasure:Reutilization of fluid catalytic cracking coke block as photothermal conversion material for water evaporation

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Particuology 2024年第5期88卷 62-70页

作者： Zhuwei Gao Chengxin Li Jingjing He Zhuo wang Xinyu Qi Lan He shihao wang Zhongxin Liu School of Chemical Engineering and Technology Hainan UniversityHaikou 570228China TJ-YZ School of Network Science Haikou University of EconomicsHaikou 570203China School of Food Science and Engineering Hainan UniversityHaikou 570228China Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education Hainan UniversityHaikou 570228China Hainan Provincial Key Laboratory of Fine Chemicals Hainan UniversityHaikou 570228China

This study aims to analyze the coking process and propose an effective method for the reutilization of fluid catalytic cracking(FCC)coke ***,we analyzed the basic characteristics and chemical composition of FCC coke *** results showed that the main components were carbon,oxygen,and aluminum,accounting for 60.8%,26.6%,and 11.5%,*** the conventional catalytic cracking reaction temperature from 500℃ to 600℃,the formation of the first aromatic hydrocarbon was particularly important for the formation of *** condensation of oil-gas-entrained catalyst particles and their heavy components was the physical cause of coking,while the dehydrogenation condensation reaction of oil-gas heavy components was the chemical *** addition,the membrane prepared by powdered coke had excellent photothermal conversion ability,which could be heated to more than 110℃ within 360 s under two fixed light *** evaporation rate of photothermal water was 5.89 kg m^(2) h^(−1),which has great industrial application *** works provide a novel and effective method of separation membrane for the reutilization of FCC coke blocks.

关键词： Coking process Reutilization of FCC coke Carbonaceous deposition Membrane Photothermal conversion

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Spatio-temporal variations in ecological spaces and their ecological carrying status in China's mega-urban agglomerations

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Journal of Geographical Sciences 2022年第9期32卷 1683-1704页

作者： wang shihao HUANG Lin XU Xinliang LI Jiahui State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China University of Chinese Academy of Sciences Beijing100049China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China

The rapid expansion of China’s urban agglomerations in recent decades has resulted in over-occupied ecological spaces and increased ecological pressure that are restricting healthy regional *** paper examines the structure and characteristics of distribution of“production-living-ecological”spaces in five mega-urban agglomerations in China:Beijing-Tianjin-Hebei(BTH),the Yangtze River Delta(YRD),Guangdong-Hong Kong-Macao Greater Bay Area(GBA),Chengdu-Chongqing(CY),and the middle reaches of the Yangtze River(MYR).We analyze spatial and temporal variations in the ecological spaces and factors influencing them from 1990 to 2020,and examine the comprehensive ecological carrying capacity and status of ecological spaces in the past 30 years based on the available water resources,regulation of water and air quality,and leisure and *** results show the following:(1)Urban agglomerations in different stages of formation and development represent varying area ratios of“ecological-production-living”*** modes of expansion and evolution of the living spaces are dominated by multi-center combinations as well as the spatial structure of ecological spaces,including barrier,compact,discrete,and fully enveloping spaces.(2)From 1990 to 2020,the area occupied by living spaces in urban agglomerations continued to increase significantly while that of spaces for ecological production *** in the GBA,ecological spaces have exhibited a trend of increase in area,especially in the past 10 *** area ratios and spatio-temporal variations in the“production-living-ecological”spaces indicate that the main functions of production and ecological spaces in mega-urban agglomerations have shifted from supply to regulation and culture,and reflect the transition from rapid urbanization to sustainable urbanization in China.(3)The comprehensive ecological carrying capacities of 78.6%,73.1%,54.5%,56.3%,and 25.8%of cities in BTH,YRD,GBA,CY and MYR are severely ove

关键词： mega-urban agglomerations “production-living-ecological”spaces ecological spaces ecological carrying capacity spatial and temporal variations

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Achieving asymmetric redox chemistry for oxygen evolution reaction through strong metal-support interactions

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Journal of Energy Chemistry 2024年第9期96卷 526-535页

作者： shihao wang Meiling Fan Hongfei Pan Jiahui Lyu Jinsong Wu Haolin Tang Haining Zhang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070HubeiChina National Energy Key Laboratory for New Hydrogen-Ammonia Energy Technologies Foshan Xianhu LaboratoryFoshan 528200GuangdongChina International School of Materials Science and Engineering(School of Materials and Microelectronics) Wuhan University of TechnologyWuhan 430070HubeiChina Nanostructure Research Centre Wuhan University of TechnologyWuhan 430070HubeiChina Hubei Key Laboratory of Fuel Cell Wuhan University of TechnologyWuhan 430070HubeiChina

Water electrolysis poses a significant challenge for balancing catalytic activity and stability of oxygen evolution reaction(OER)*** this study,we address this challenge by constructing asymmetric redox chemistry through elaborate surface OO–Ru–OH and bulk Ru–O–Ni/Fe coordination moieties within single-atom Ru-decorated defective NiFe LDH nanosheets(Ru@d-NiFe LDH)in conjunction with strong metal-support interactions(SMSI).Rigorous spectroscopic characterization and theoretical calculations indicate that single-atom Ru can delocalize the O 2p electrons on the surface and optimize d-electron configurations of metal atoms in bulk through ***^(18)O isotope labeling experiment based on operando differential electrochemical mass spectrometry(DEMS),chemical probe experiments,and theoretical calculations confirm the encouraged surface lattice oxygen,stabilized bulk lattice oxygen,and enhanced adsorption of oxygen-containing intermediates for bulk metals in Ru@d-NiFe LDH,leading to asymmetric redox chemistry for *** Ru@d-NiFe LDH electrocatalyst exhibits exceptional performance with an overpotential of 230 mV to achieve 10 mA cm^(−2)and maintains high robustness under industrial current *** approach for achieving asymmetric redox chemistry through SMSI presents a new avenue for developing high-performance electrocatalysts and instills confidence in its industrial applicability.

关键词： Reaction redox chemistry Strong metal-support interactions Layered double hydroxides Electrocatalysts Water electrolysis

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