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Steady State Rheological Characteristic of Semisolid Magnesium Alloy

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Journal of Materials Science & Technology 2007年第5期23卷 637-640页

作者： Fengyun YAN Liping SUN yi gong Yuan hao State Key Laboratory of Gansu Advanced Non-Ferrous Metal Materials Lanzhou University of Technology Lanzhou 730050 China

Isothermal compressive experiments at different temperatures, strain rates and holding time for semisolid AZ91D, Zr modified AZ91D and MB15 alloy with higher solid volume fraction were carried out by using Gleeble-1500D simulator and the true stress-strain curves were given directly. The relationship of apparent viscosity vs temperature, shear rate and holding time of the three kinds of semi-solid magnesium alloys, as well as isothermal steady state rheological characteristic and mechanical behavior were studied. The results show that the three magnesium alloys had the characteristic of shear-thinning. The rheological characteristic of the semi-solid MB15 is different from that of semi-solid AZ91D. The semi-solid MB15 has higher apparent viscosity and deformation resistance.

关键词： Semi-solid magnesium alloy Apparent viscosity Rheological characteristic Deformation resistance

Palladium single atoms from melting nanoparticles on WO_(3-x) for boosted hydrogen evolution reaction

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Journal of Energy Chemistry 2024年第4期91卷 637-644页

作者： Zhongmiao gong Zhigang Chen hao Li Guang Yang Min Yuan Zhiyun Li Xueying Wan yi Cui School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026AnhuiChina i-lab Vacuum Interconnected Nanotech WorkstationSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123JiangsuChina School of Materials Science and Engineering Chongqing University of TechnologyChongqing 400054China Key Laboratory of Precision and Intelligent Chemistry School of Chemistry and Materials ScienceHefei National Research Center for Physical Sciences at the MicroscaleNational Synchrotron Radiation LaboratorySchool of Nuclear Science and TechnologyUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

Surface-supported isolated atoms in single-atom catalysts(SACs)grant maximum utilization of metals in heterogeneous ***,we report a feasible pyrolysis strategy to synthesize Pd single atoms by thermally melting Pd nanoparticles on an oxygen-vacancy-rich tungsten-oxide matrix at reduction *** ambient pressure X-ray photoelectron spectroscopy was used to monitor the formation of zero-valence Pd single atoms and the increased metallic feature of WO_(3-x)***,the as-obtained zero-valence Pd single-atom catalyst exhibits a markedly boosted HER activity with a low overpotential(η_(10)=70 mV)at the current density of 10 mA/cm2and a small Tafel slope(b=68 mV/dec),nearly 150 mV and a 3,0-fold enhancement than those of Pd nanoparticles(η_(10)=220 mV,b=133 mV/dec)under the same *** addition,quasi in situ XPS results suggest the hydrogen spillover effect is more likely to occur on Pd single atoms during the electrochemical *** work may pave an interesting route for the rational design of highly-efficient single-atom catalysts,and the elucidation of corresponding enhanced reaction mechanisms by the utilization of advanced characterization techniques.

关键词： Pd WO_(3-x) Single-atom catalysts NAP-XPS HER

Accurate Distinction of Weak and Strong AC Grids for Emerging Hierarchical-Infeed LCC-UHVDC Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 772-777页

作者： hao Xiao Xianzhong Duan yi Zhang Department of Electrical and Computer Engineering University of ManitobaWinnipeg R3T 2N2ManitobaCanada State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security and High Efficiency Key LaboratorySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina RTDS Technologies Inc. Winnipeg R3T 2E1ManitobaCanada

Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.

关键词： Hierarchical-Infeedinteractive effective short-circuit ratio hierarchical-infeed LCC-UHVDC systems inter-inverter interactions strong AC grids weak AC grids

Exploring the mechanisms of calcium carbonate deposition on various substrates with implications for effective anti-scaling material selection

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Petroleum Science 2024年第4期21卷 2870-2880页

作者： Lu gong Fei-yi Wu Ming-Fei Pan Jun Huang hao Zhang Jing-Li Luo Hong-Bo Zeng College of Science China University of Petroleum Beijing Key Laboratory of Optical Detection Technology for Oil and Gas China University of Petroleum Basic Research Center for Energy Interdisciplinary College of Science China University of Petroleum Department of Chemical and Materials Engineering University of Alberta Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Ministry of Education) School of Mechanical Engineering Shandong University

The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries,leading to issues such as heat exchanger failures and pipeline clogging. It is of practical and fundamental importance to understand the scaling mechanisms and develop efficient anti-scaling strategies. However,the underlying surface interaction mechanisms of scalants(e.g., calcite) with various substrates are still not fully understood. In this work, the colloidal probe atomic force microscopy(AFM) technique has been applied to directly quantify the surface forces between calcite particles and different metallic substrates,including carbon steel(CR1018), low alloy steel(4140), stainless steel(SS304) and tungsten carbide,under different water chemistries(i.e., salinity and p H). Measured force profiles revealed that the attractive van der Waals(VDW) interaction contributed to the attachment of the calcium carbonate particles on substrate surfaces, while the repulsive electric double layer(EDL) interactions could inhibit the attachment behaviors. High salinity and acidic p H conditions of aqueous solutions could weaken the EDL repulsion and promote the attachment behavior. The adhesion of calcite particles with CR1018 and4140 substrates was much stronger than that with SS304 and tungsten carbide substrates. The bulk scaling tests in aqueous solutions from an industrial oil production process showed that much more severe scaling behaviors of calcite was detected on CR1018 and 4140 than those on SS304 and tungsten carbide, which agreed with surface force measurement results. Besides, high salinity and acidic p H can significantly enhance the scaling phenomena. This work provides fundamental insights into the scaling mechanisms of calcite at the nanoscale with practical implications for the selection of suitable antiscaling materials in petroleum industries.

关键词： Scaling phenomenon Metallic substrates Surface forces Bulk scaling tests

Freeze-induced acceleration of iodide oxidation and consequent iodination of dissolved organic matter to form organoiodine compounds

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Journal of Environmental Sciences 2024年第10期144卷 67-75页

作者： Xuexin gong Mei He Zhineng hao Rusong Zhao Jingfu Liu School of Resources and Environment Yangtze UniversityWuhan 430100China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Qilu University of Technology(Shandong Academy of Sciences) Shandong Analysis and Test CenterKey Laboratory for Applied Technology of Sophisticated Analytical Instruments of Shandong ProvinceJinan 250014China Institute of Environment and Health Jianghan UniversityWuhan 430056China

Freeze-induced acceleration of I–oxidation and the consequent iodination of dissolved organic matter(DOM)contribute to the formation of organoiodine compounds(OICs)in cold *** formed OICs may be a potentially important source of risk and are very closely with the environment and human ***,we investigated the acceleration effects of the freeze process on I–oxidation and the formation of *** comparison to reactive iodine species(RIS)formed in aqueous solutions,I–oxidation and RIS formation were greatly enhanced in frozen solution and were affected by pH,and the content of I–and ***-thaw process further promoted I–oxidation and the concentration of RIS reached 45.7μmol/L after 6 freeze-thaw *** consequent products of DOM iodination were greatly promoted in terms of both concentration and *** total content of OICs ranged from 0.02 to 2.83μmol/L under various *** 183–1197 OICs were detected by Fourier transform ion cyclotron resonance mass spectrometry,and more than 96.2%contained one or two iodine *** OICs had aromatic structures and were formed via substitution and addition *** findings reveal an important formation pathway for OICs and shed light on the biogeochemical cycling of iodine in the natural aquatic environment.

关键词： Freeze process Dissolved organic matter(DOM) Iodination Organoiodine compounds(OICs) Ultrahigh resolution mass spectrometry

Preparation and properties of ZrO_(2)-strengthened porous mullite insulation materials using Y_(2)O_(3) additive

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Journal of Iron and Steel Research International 2024年第6期31卷 1514-1521页

作者： Wang-zhi Yu yi-hong Shi Ping Liu Yong-wan Wu Cheng-hao Song Xian-gong Deng Xiang Ding Song-lin Ran yi Zhang Hai-jun Zhang Hai-liang Deng Advanced Ceramics Research Center School of Materials Science and EngineeringAnhui University of TechnologyMa'anshan 243002AnhuiChina The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

ZrO_(2)-strengthened porous mullite insulation materials were prepared by foaming technology utilizing ZrSiO_(4) and Al_(2)O_(3) as primary materials and Y_(2)O_(3) as an *** effects of Y_(2)O_(3) contents on the phase composition,microstructure,mechanical properties,and heat conductivity of the porous mullite insulation materials were investigated.A suitable Y_(2)O_(3) content could promote phase transition of monoclinic ZrO_(2)(m-ZrO_(2))to tetragonal ZrO_(2)(t-ZrO_(2)),reduce pore size,and improve the strengths of as-prepared *** cold crushing strength and bending strength of as-prepared specimens with a 119µm spherical pore size using 6 wt.%Y_(2)O_(3) were 35.2 and 13.0 MPa,respectively,with a heat conductivity being only 0.248 W/(m K).

关键词： Porous mullite insulation material Zirconium oxide Y_(2)O_(3) Mechanical property Heat conductivity

Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

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Journal of Iron and Steel Research International 2024年第2期31卷 488-500页

作者： Tao-long Xu Si-han Guo gong-zhen He hao-yu Han Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina Sichuan East Gas Transmission Sales Center of Sinopec Natural Gas Branch Wuhan430074HubeiChina

Hydrogen embrittlement of pipelines depends on the hydrogen-induced cracking behavior of the pipeline steel *** on molecular dynamics analysis,the ferrite–cementite(α-Fe/Fe3C)lamellar atomic structure with the Bagaryatskii orientation relationship was established,and stepwise relaxation of the conjugate gradient energy minimization and constant-temperature and constant-pressure relaxation were performed under NPT(the isothermal–isobaric)*** mechanical property curves of theα-Fe/Fe3C models were obtained under different cementite terminal plane structures,and the evolution of the atomic structure was analyzed in *** addition,the influence of different hydrogen concentrations,different temperatures,different strain rates,changes in voids,and different micro-degrees of freedom on the deformation and failure mechanism of the model was investigated,aiming to provide a reliable way to explore the micro-mechanism of macro-cracking behavior of pipeline steel.

关键词： Ferrite-cementite lamellar structure Pipeline steel Failure mechanism Crack propagation Molecular dynamics

DLF-YOLOF:an improved YOLOF-based surface defect detection for steel plate

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Journal of Iron and Steel Research International 2024年第2期31卷 442-451页

作者： Guang-hu Liu Mao-xiang Chu Rong-fen gong Ze-hao Zheng School of Electronic and Information Engineering University of Science and Technology LiaoningAnshan114051LiaoningChina

Surface defects can affect the quality of steel *** methods based on computer vision are currently applied to surface defect detection of steel ***,their real-time performance and object detection of small defect are still *** improved object detection network based on You Only Look One-level Feature(YOLOF)is proposed to show excellent performance in surface defect detection of steel plate,called ***,the anchor-free detector is used to reduce the network ***,deformable convolution network and local spatial attention module are introduced into the feature extraction network to increase the contextual information in the feature ***,the soft non-maximum suppression is used to improve detection accuracy ***,data augmentation is performed for small defect objects during training to improve detection *** show the average precision and average precision for small objects are 42.7%and 33.5%at a detection speed of 62 frames per second on a single GPU,*** shows that DLF-YOLOF has excellent performance to meet the needs of industrial real-time detection.

关键词： Steel surface defects detection YOLOF Anchor-free detector Small object detection Real-time detection

Recent progress in Prussian blue electrode for electrochromic devices

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Frontiers in Energy 2024年第2期18卷 160-186页

作者： Yongting ZHANG Wanzhong LI Hui gong Qianqian ZHANG Liang YAN hao WANG Key Laboratory for New Functional Materials of the Ministry of Education Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China School of Instrument Science and Engineering Southeast UniversityNanjing 210096China Beijing Aerospace Times Laser Inertial Technology Company Beijing 100094China

Great progress has been made in the electrochromic(EC)technology with potential applications in various *** one of the most promising EC materials,Prussian blue(PB)has attracted great attention due to its excellent EC performance,such as low cost,easy synthesis,rich color states,chemical stability,suitable redox potential,and fast color-switching *** review summarizes the recent progress in PB electrodes and devices,including several typical preparation techniques of PB electrodes,as well as the recent key strategies for enhancing EC performance of PB ***,PB-based electrochromic devices(ECDs)have been widely used in various fields,such as smart windows,electrochromic energy storage devices(EESDs),wearable electronics,smart displays,military camouflage,and other *** opportunities and obstacles are suggested for advancing the development of PB-based *** comprehensive review is expected to offer valuable insights for the design and fabrication of sophisticated PBbased ECDs,enabling their practical integration into realworld applications.

关键词： Prussian blue electrochromism energy storage smart windows