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Effect of CO_2 partial pressure on SCC behavior of welded X80 pipeline in simulated soil solution

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Acta Metallurgica Sinica(English Letters) 2011年第1期24卷 65-74页

作者： ming WU Xu CHEN Chuan HE jun XIAO College of Petroleum Engineering Liaoning Shihua University Eushun 113001 China

The stress corrosion cracking （SCC） behavior of welded X80 pipeline steel in simulated Ku＇erle soil solution was studied by means of electrochemical impedance spectroscopy （EIS） and slow strain rate tests （SSRT）. The microstructure of the welded steel was observed by optical microscopy （OM）. It is demonstrated that the microstructure of the weld metal consists of acicular ferrite and grain boundary ferrite, while that of heat affected zone （HAZ） is a mixture of acicular ferrite and bainitic ferrite micro- constituents. The microstructure of the base steel is composed of ferrite and pearlite. The anodic dissolution of X80 pipeline steel in simulated Ku＇erle soil solution could be enhanced and the SCC sensitivity increased with the increase of CO2 partial pressure. The SCC mechanism of X80 pipeline is a mixing mechanism of hydrogen embrittlement combined with anodic dissolution, and the hydrogen embrittlement plays a leading role. The higher SCC sensitivity of the weld metal was attributed to the metallurgical transformation, local hardening and residual stress.

关键词： X80 steel Weld metal CO2 partial pressure SCC

Closed-form algorithms for computing the intersection of two subspaces

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Journal of Systems Engineering and Electronics 2019年第2期30卷 245-250页

作者： YAN Fenggang LIU Shuai WANG jun JIN ming School of Information Science and Engineering Harbin Institute of Technology at Weihai

Finding the intersection of two subspaces is of great interest in many fields of signal processing. Over several decades,there have been numerous formulas discovered to solve this problem, among which the alternate projection method(APM) is the most popular one. However, APM suffers from high computational complexity, especially for real-time applications. Moreover, APM only gives the projection instead of the orthogonal basis of two given subspaces. This paper presents two alternate algorithms which have a closed form and reduced complexity as compared to the APM technique. Numerical simulations are conducted to verify the correctness and the effectiveness of the proposed methods.

关键词： orthogonal projection singular value decomposition alternate projection method (APM) intersection

A spherical cavity expansion model for penetration of ogival-nosed projectiles into concrete targets with shear-dilatancy

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Acta Mechanica Sinica 2011年第6期27卷 1001-1012页

作者： Tao He He-ming Wen Xiao-jun Guo CAS Key Laboratory for Mechanical Behavior and Design of Materials University of Science and Technology of China 230027 Hefei China

A dynamic spherical cavity-expansion penetration model is suggested herein to predict the penetration and perforation of concrete targets struck normally by ogivalnosed *** dilatancy as well as compressibility of the material in comminuted region are considered in the paper by introducing a dilatant-kinematic relation.A procedure is first presented to compute the radial stress at the cavity surface and then a numerical method is used to calculate the results of penetration and perforation with friction being taken into *** influences of various target parameters such as shear strength,bulk modulus,density,Poisson＇s ratio and tensile strength on the depth of penetration are *** is shown that the model predictions are in good agreement with available experimental *** is also shown that the shear strength plays a dominant role in the target resistance to penetration.

关键词： Spherical cavity expansion Shear dilatancy Ogival-nosed projectile Concrete target Penetration Perforation

Nickel release rate of 18KW gold alloy for ornaments

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Rare Metals 2013年第1期32卷 33-39页

作者： jun-Ping Yuan Wei Li Wen-ming Liu Department of Materials Science and Engineering Jinan University Jewelry Institute of Guangzhou Panyu Polytechnic

Nickel is widely used as a bleaching element in white gold alloys, but it is a potential allergen. In this paper, a popular 18 KW gold alloy, often called ＂safe nickel,＂ was chosen as the experimental material; its nickel release rates under six different processing conditions were evaluated according to the EN1811 standard. The results reveal that both the surface processing method and heat treatment technology significantly affect the nickel release rate. A coarse surface releases more nickel ions than a smooth surface. The sample normalized at 700 ~C in the single region has a lower nickel release rate than the one treated at 550 ~C in the two-phase phase region, while high temperature normalizing at 800 ~C will accelerate it. All the measured nickel release rates of the experimental material under various processing conditions exceed the permitted threshold value in the Nickel Directive, which indicates that there exists the potential risk of nickel- induced allergy when it is used to make jewelries, espe- cially for piercing types.

关键词： 18 KW Gold alloy Jewelry Nickel releaserate Nickel Directive Processing conditions

Effect of rare earth samarium addition on the kinetics of precipitation in Al-Cu-Mn casting alloy

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 155-161页

作者： Zhong-wei Chen ming-jun Tang Kai Zhao State Key Laboratory of Solidification Processing Northwestern Polytechnical University

The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.

关键词： aluminum copper alloys rare earth additions samarium precipitation kinetics

Design of new chemicals for advanced electrolytes

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Science China Chemistry 2024年第5期67卷 1378-1380页

作者： Haoran Cheng Zheng Ma Qian Li jun ming State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China University of Science and Technology of China Hefei 230026China

This highlight is inspired by a recent article in Nature Energy in which Liu and co-workers [1] from Tsinghua University designed a new asymmetric lithium salt (i.e., lithium 1,1,1-trifluoro-N-[2-[2-(2-methoxy ethoxy)ethoxy]ethyl] methanesulfonamide (Li FEA)) and applied it as a new lithium-salt additive in the conventional carbonate-based electrolyte,overcoming the incompatibility issue of carbonate electrolytes with lithium metal in lithium metal batteries (LMBs),even achieving a fast-charging feature.

关键词： lithium carbonate electrolyte

Structural and functional variations of phytoplankton communities in the face of multiple disturbances

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Journal of Environmental Sciences 2021年第2期33卷 287-297页

作者： jun R.Yang Xiaoqing Yu Huihuang Chen Yi-ming Kuo jun Yang Engineering Research Center of Ecology and Agricultural Use of wetland(Ministry of Education)College of Agriculture Yangtze UniversityJingzhou 434025China Aquatic Ecohealth Group Fujian Key Laboratory of Watershed EcologyKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China School of Environmental Studies China University of GeosciencesWuhan 430074China

The global decline of freshwater biodiversity caused by climate change and human activities are supposed to disrupt ecosystem services related to water quality and alter the structure and function of aquatic communities across space and time,yet the effects of the combination of these factors on plankton community ecosystem has received relatively little *** study aimed to explore the impacts of disturbances(*** activity,temperature,precipitation,and water level)on phytoplankton community structure(*** evenness and community composition)and function(*** use efficiency)in four subtropical reservoirs over 7 years from 2010 to *** results showed that community turnover(measured as community dissimilarity)was positively related to disturbance frequency,but no significant correlation was found between phytoplankton biodiversity(***)and disturbance *** resource use efficiency(RUE=phytoplankton biomass/total phosphorus)was increased with a higher frequency of disturbance with an exception of *** RUE of Cyanobacteria and diatoms showed significantly negative correlations with their community evenness,while the RUE of Chlorophyta exhibited a positive correlation with their community *** suggest that multiple environmental disturbances may play crucial roles in shaping the structure and functioning of plankton communities in subtropical reservoirs,and mechanism of this process can provide key information for freshwater uses,management and conservation.

关键词： Algae Biodiversity Community ecology Plankton Resource use efficiency Subtropical reservoir

Room-temperature multiferroicity and diversified magnetoelectric couplings in 2D materials

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National Science Review 2020年第2期7卷 373-380页

作者： Tingting Zhong Xiaoyong Li Menghao Wu jun-ming Liu School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Laboratory of Solid State Microstructures Nanjing University

Multiferroics are rare in nature due to the mutual exclusive origins of magnetism and ferroelectricity. The simultaneous coexistence of robust magnetism/ferroelectricity and strong magnetoelectric coupling in single multiferroics is hitherto unreported, which may also be attributed to their potential conflictions. In this paper, we show the first-principles evidence of such desired coexistence in ultrathin-layer CuCrS2and CuCrSe2. The vertical ferroelectricity is neither induced by an empty d shell nor spin-driven, giving rise to an alternative possibility of resolving those intrinsic exclusions and contradictions. Compared with their bulk phases, the ferromagnetism in the thin-layer structures(two–six layers) can be greatly stabilized due to the enhanced carrier density and orbital shifting by vertical polarization, and the Curie temperatures of both ferromagnetism and ferroelectricity can be above room temperature. Moreover, a considerable net magnetization can be reversed upon ferroelectric switching, where the change in spin-resolved band structure also renders efficient ‘magnetic reading + electrical writing’. The thickness-different layers may even exhibit diversified types of magnetoelectric coupling, which both enriches the physics of multiferroics and facilitates their practical applications.

关键词： 2D multiferroics room-temperature ferromagnetism and ferroelectricity diversified magnetoelectric couplings vertical polarizations first-principles calculations

2D/2D heterojunction interface:Engineering of 1T/2H MoS_(2) coupled with Ti_(3)C_(2)Tx heterostructured electrocatalysts for pH-universal hydrogen evolution

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Journal of Materials Science & Technology 2024年第12期179卷 86-97页

作者： Jian Yiing Loh Feng ming Yap Wee-jun Ong School of Energy and Chemical Engineering Xiamen University MalaysiaSepangSelangor Darul Ehsan 43900Malaysia Center of Excellence for NaNo Energy&Catalysis Technology(CONNECT) Xiamen University MalaysiaSepangSelangor Darul Ehsan 43900Malaysia State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Gulei Innovation Institute Xiamen UniversityZhangzhou 363200China Shenzhen Research Institute of Xiamen University Shenzhen 518057China

Two-dimensional(2D)materials have come to light due to their unique thickness that owns abundant exposed edges with enhanced electrocatalytic properties.2D molybdenum disulfide(MoS_(2))nanosheet has aroused considerable attention due to its tunable surface chemistry and high electrochemical sur-face ***,several shortcomings associated with MoS_(2),such as its naturally existing semi-conducting 2H phase,which has limited active sites due to the inert basal plane,restrict its application in water *** into account the benefits of the 1T/2H phase of MoS_(2),as well as the importance of engineering 2D/2D heterojunction interface for boosted electrocatalysis,metallic Ti_(3)C_(2)Tx was integrated with 1T/2H MoS_(2) to develop 2D/2D 1T/2H MoS_(2)/Ti_(3)C_(2)Tx heterostructured ***,with only 25%of the intercalating agent,1T/2H MoS_(2) with the highest 1T phase content of~82%was successfully *** was further incorporated with 1 wt%of Ti_(3)C_(2)Tx through a com-bination of ultrasonication and mechanical stirring *** 1T/2H MoS_(2)(25D)/Ti_(3)C_(2)Tx-1(MTC-1)manifested outstanding electrocatalytic performance with an overpotential and Tafel slope of 280 mV(83.80 mV dec^(-1))and 300 mV(117.2 mV dec^(-1)),for catalyzing acidic and alkaline medium HER,***,the as-prepared catalysts also illustrated long-term stability for more than 40 *** coupling method for the 2D nanosheets is crucial to suppress the oxidation of Ti_(3)C_(2)Tx and the restack-ing issue of 2D *** superior HER activity is ascribed to the synergistic effect between the heterostructure,enhancing the electronic structure and charge separation *** intrinsic prop-erty of the catalyst further confirms by turnover frequency(TOF)*** such,this research paves the way for designing high-efficiency 2D electrocatalysts and sheds light on the further advancement of tunable 2D electrocatalysts for robust wa

关键词： 2D/2D electrocatalysts Phase engineering pH universal Molybdenum disulfide Ti_(3)C_(2)Tx