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Journal of Rare Earths 2024年第1期42卷 228-236,I0008页

作者： Wen He dunqiang tan Zhiqiang Yi Zhiqiang Liu School of Materials Science and Engineering Nanchang UniversityNanchang330031China Instrumental Analysis Center of Nanchang Hangkong University Nanchang330063China

In order to reduce or eliminate the adverse effects of calcium impurity,the interaction of Ca and rare earth Y co-doping on the preparation of WC-Co cemented carbides was investigated.X-ray diffraction,scanning electron microscopy and transmission electron microscopy were employed to analyze the phase compositions,particle sizes and morphologies of them,*** results show that the second type of"yttrium barrier effect"is observed and the adverse influence of Ca-rich phase on tungsten powder can be eliminated by *** flexural strength and fracture toughness of YG6-0.01%Ca+0.09%Y alloy are 2199.5 MPa and 11.49 MPa·m^(1/2),showing improvement of 6.5% and 2.7% compared to YG6 alloy,*** evolutions of Ca-rich phase and Y-rich phase at the every alloy preparation stage of WO_(3),W,WC and cemented carbides are ***,the strengthening mechanism of WC-Co cemented carbide with co-addition of Ca and Y is proposed.

关键词： Yttrium barrier effect Ca-rich phase WC-Co cemented Carbide Microstructures Mechanisms Rare earths

On ignition point of Mg-Ca alloy under nitrogen atmosphere

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China Foundry 2011年第3期8卷 282-285页

作者： tan dunqiang Yang Xiaoxia Zhan Yijie Xiao Dongfei School of Materials Science and Engineering Nanchang University Nanchang 330031 China

The production cost will be greatly reduced if nitrogen can be used instead of inert gas in the spray forming process of magnesium alloys, but the heat from the reaction between magnesium alloys and nitrogen makes magnesium alloy burn easily. To solve the problem above, the ignition point of Mg-Ca alloy under nitrogen atmosphere was studied using a home-made experimental device and DSC-DTA. Results show that under nitrogen atmosphere, Ca addition has a great effect on the ignition point of Mg alloy. The ignition point of the Mg-5Ca bulk even exceeds 1,030℃, and the alloy can be held for 30 min at 900℃ without burning;while the average ignition point of Mg-5Ca powders is lower than 700℃, and it increases with the increasing particle size. Moreover, the purity of nitrogen must be in a certain scope;Mg-Ca alloy shows a higher ignition point under nitrogen with a purity of 99.5%. Based on the experimental results, the best adding content of Ca and the purity of nitrogen were determined, and the security and economic performance of preparing magnesium alloys by spray deposition were improved with nitrogen as atomizing gas.

关键词： Mg-Ca 合金点火点氮

Mn含量及退火工艺对Cu-xMn-0.2Ce-0.2Zr合金组织性能的影响

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金属热处理 2023年第6期48卷 219-228页

作者：徐亮亮谭敦强南昌大学物理与材料学院江西南昌330031

采用显微组织观察和X射线衍射分析,通过电阻率和电阻温度系数、显微维氏硬度及Tafel极化曲线测量,研究了Mn含量及退火工艺对冷轧Cu-xMn-0.2Ce-0.2Zr(x=5、6、7、8)合金组织性能的影响。结果表明,随着Mn含量的增加,电阻率逐渐增加,电阻... 详细信息

采用显微组织观察和X射线衍射分析,通过电阻率和电阻温度系数、显微维氏硬度及Tafel极化曲线测量,研究了Mn含量及退火工艺对冷轧Cu-xMn-0.2Ce-0.2Zr(x=5、6、7、8)合金组织性能的影响。结果表明,随着Mn含量的增加,电阻率逐渐增加,电阻温度系数逐渐降低,且合金的择优取向均为(220)_(Cu)晶面。在250、350、450和550℃退火后,合金发生回复和再结晶,使得内应力降低,显微维氏硬度随着退火温度的升高和保温时间的延长而下降。当Mn含量为7%时,Cu-7Mn-0.2Ce-0.2Zr合金得到良好的综合性能。经350℃退火1 h、水冷后,电阻率为22.3μΩ·cm,电阻温度系数(TCR_(25-125℃))为116×10^(-6)℃^(-1)。自腐蚀电位和自腐蚀电流密度分别为-0.172 V和1.86μA/cm^(2)。说明Cu-7Mn-0.2Ce-0.2Zr合金在工作温度范围内具有优良的电学性能,同时也兼具较好的耐蚀性能。

关键词： Cu-Mn合金退火工艺 Mn含量电阻率电阻温度系数 Tafel极化曲线组织硬度

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压煮法制备超细含钇钨粉的工艺研究

中国钨业 2023年第5期38卷 31-36页

作者：沈璐瑶谭敦强南昌大学物理与材料学院江西南昌330031

机械合金法和湿掺杂法制备含稀土元素的钨复合纳米粉末前驱体存在杂质引入、稀土元素偏聚等问题,导致颗粒均匀性差而影响合金性能。本研究采用压煮法制备含钇钨粉,探究了压煮温度、固液比对含钇钨粉粒径及均匀性的影响。结果表明,相比... 详细信息

机械合金法和湿掺杂法制备含稀土元素的钨复合纳米粉末前驱体存在杂质引入、稀土元素偏聚等问题,导致颗粒均匀性差而影响合金性能。本研究采用压煮法制备含钇钨粉,探究了压煮温度、固液比对含钇钨粉粒径及均匀性的影响。结果表明,相比于湿掺杂法,压煮法改善了钇元素的分布形式进而达到细化钨晶粒的目的,在压煮温度为220℃、固液比为6 g/mL的工艺条件下制备得到的含钇钨粉粒径小且均匀性良好,其平均粒径可以达到0.25μm。

关键词：钨粉氧化钇压煮法晶粒细化

Influence of ambient temperature on the CO_(2)emitted of light-duty vehicle

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Journal of Environmental Sciences 2024年第6期140卷 59-68页

作者： Dan tan Yachao Wang Jianwei tan Jiachen Li Changyu Wang Yunshan Ge School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China

Because of global warming,people have paid more attention to greenhouse gas emitted by *** quantify the impact of temperature on vehicle CO_(2)emissions,this study was conducted using the world light vehicle test cycle on two light-duty E10 gasoline vehicles a ambient temperatures of-10,0,23,and 40℃,and found that CO_(2)emission factors of Vehicle1 in the low-speed phase were 22.07%and 20.22%higher than those of Vehicle 2 at cold star and hot start under-10℃.The reason was vehicle 1 had a larger displacement and more friction pairs than vehicle *** was the highest CO_(2)emission at the low-speed phase due to low average speed,frequent acceleration,and *** CO_(2)temperature factor and the ambient temperature had a strong linear correlation(R2=0.99).According to CO_(2)temperature factors and their relationships,CO_(2)emission factors of other ambien temperatures could be calculated when the CO_(2)emission factor of 23℃was obtained,and the method also could be used to obtain the CO_(2)temperature factors of different *** separate the effect of load setting and temperature variation on CO_(2)emission quantitatively a method was *** results showed that the load setting was dominant for the CO_(2)emission *** with 23℃,the CO_(2)emission for vehicle 1 caused by load setting variation were 62.83 and 47.42 g/km,respectively at-10 and 0℃,while those fo vehicle 2 were 45.01 and 35.63 g/km,respectively.

关键词： CO_(2)emission Ambient temperature E10 gasoline Light-duty vehicle WLTC

Best Paper Award 2022

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Building Simulation 2024年第1期17卷 1-2页

作者： Gang tan College of Civil Engineering and Architecture Zhejiang University HangzhouZhejiang 310058China

I am pleased to announce that the following paper has been awarded the Best Review Paper 2022,which stands out from the 24 review papers published by Building Simulation from 2018(Volume 11)to 2022(Volume 15):Yuejing Zhao&Bin Zhao."Emissions of air pollutants from Chinese cooking:A literature review."Building Simulation,2018,11(5):977-995.

关键词： cooking stands award

Preface to the Special Issue:AI Applications in Atmospheric and Oceanic Science:Pioneering the Future(Part I)

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Advances in Atmospheric Sciences 2024年第7期41卷 1279-1280页

作者： Zhemin tan Key Laboratory of Mesoscale Severe Weather Ministry of Educationand School of Atmospheric SciencesNanjing UniversityNanjing 210023China

As AI continues to establish itself as a cornerstone technology across various industries and scientific disciplines,its profound impact on atmospheric and oceanic science is becoming increasingly *** advantages of AI in surmounting obstacles within our field are undeniable,as evidenced by breakthroughs in weather forecasting(e.g.,Bi et al.,2023),climate prediction(e.g.,Ham et al.,2019),AI-based parameterization schemes(e.g.,Rasp et al.,2018;Wang and tan,2023),and *** the transformative potential of AI in atmospheric and oceanic science,this special issue endeavors to explore the extensive applications of AI in our domain.

关键词： weather forecasting prediction

A Novel Extremum Seeking Control to Enhance Convergence and Robustness in the Presence of Nonlinear Dynamic Sensors

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Journal of Systems Science & Complexity 2024年第1期37卷 3-21页

作者： LIU Hengchang tan Ying OETOMO Denny School of Electrical Mechanical and Infrastructure EngineeringThe University of MelbourneParkville VIC 3010Australia

This paper focuses on optimizing an unknown cost function through extremum seeking(ES)control in the presence of a slow nonlinear dynamic sensor responsible for measuring the *** contrast to traditional perturbation-based ES control,which often suffers from sluggish convergence,the proposed method eliminates the time-scale separation between sensor dynamics and ES control by using the relative degree of the nonlinear sensor *** improve the convergence rate,the authors incorporate high-frequency dither signals and a *** enhance the robustness with the existence of rapid disturbances,an off-the-shelf linear high-gain differentiator is *** first result demonstrates that,for any desired convergence rate,with properly tuned parameters for the proposed ES algorithm,the input of the cost function can converge to an arbitrarily small neighborhood of the optimal solution,starting from any initial condition within any given compact ***,the second result shows the robustness of the proposed ES control in the presence of sufficiently fast,zero-mean periodic *** results substantiate these theoretical findings.

关键词： Averaging extremum seeking optimization singular perturbation time-scale separation

Amorphous hybrid tungsten oxide–nickel hydroxide nanosheets used as a highly efficient electrocatalyst for hydrogen evolution reaction

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Nano Research 2024年第4期17卷 2499-2508页

作者： Chao Lyu Chenghai Dai Yiwei tan State Key Laboratory of Materials-Oriented Chemical Engineering School of Chemistry and Chemical EngineeringNanjing Tech UniversityNanjing 211816China

There are more challenges for alkaline hydrogen evolution reaction(HER)via simultaneously expediting the electron-coupled water dissociation process(Volmer step)and the following electrochemical H_(2) desorption(Heyrovsky step).Hybrid amorphous electrocatalysts are highly desirable for efficient hydrogen evolution from water-alkali electrolyzers due to the bifunctionality for the different elementary steps of HER and optimal interactions with water molecules and the reactive hydrogen intermediates(Had).Herein,the synthesis of amorphous hybrid ultrathin(tungsten oxide/nickel hydroxide)hydrate(a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O)nanosheets on nickel foam(NF)for efficient alkaline HER is *** structural and composition features of a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O are characterized in *** resulting a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O/NF electrocatalyst with the synergistic effect of both hybrid components for the HER elementary steps shows greatly improved the activity and durability for the HER with a low overpotential of-41 and-163 mV at-10 and-500 mA·cm^(-2),respectively,a Tafel slope as low as-72.9 mV·dec^(-1),and long-term stability of continuous electrolysis for at least 150 h accompanying by inappreciable overpotential change in 1 M *** the hybrid a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O,Ni(OH)_(2) and WO_(3) moieties are separately responsible for accelerating dissociative adsorption of water and weakening Had adsorption strength,which is beneficial to the improvement of the alkaline HER activity.

关键词： amorphous nanomaterial bimetallic electrocatalyst tungsten oxide ultrathin nanosheet hydrogen evolution reaction

An Improved Method for Approximating the Infinite-Horizon Value Function of the Discrete-Time Switched LQR Problem

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Journal of Systems Science & Complexity 2024年第1期37卷 22-39页

作者： HOU tan LI Yuanlong LIN Zongli Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240China Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904-4743USA

This paper considers the problem of approximating the infinite-horizon value function of the discrete-time switched LQR *** particular,the authors propose a new value iteration method to generate a sequence of monotonically decreasing functions that converges exponentially to the value *** method facilitates us to use coarse approximations resulting from faster but less accurate algorithms for further value iteration,and thus,the proposed approach is capable of achieving a better approximation for a given computation time compared with the existing *** numerical examples are presented in this paper to illustrate the effectiveness of the proposed method.

关键词： Optimal control switched linear systems switched LQR problem.