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Precipitation evolution and properties of Cu-15Ni-8Sn alloys via Al microalloying during ageing

Rare Metals 2024年第10期43卷 5216-5228页

作者： wei Luo Li-Jun Peng Xu-Jun Mi Hao-feng Xie Yi-Cheng Cao shu-Hui Huang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China School of Materials Science and Engineering South China University of TechnologyGuangzhou 510640China

Studies have shown that microalloying Cu-Ni-Sn alloys using Al inhibits discontinuous precipitation reactions;however,the mechanism has not been investigated ***,this study explored the properties and precipitation evolution of Cu-15Ni-8Sn alloys without and with 1 wt%Al(Cu-15Ni-8Sn-1Al)during ageing at 500℃ through X-ray diffraction(XRD),scanning electron microscopy and high-angle annular dark-field scanning transmission electron *** results revealed that in Cu-15Ni-8Sn alloy,DO_(22)ordering first occurred after spinodal decomposition,subsequently transitioning to an L1_(2)ordering phase,during which the discontinuous precipitates gradually nucleated at the grain boundaries and formed *** alloy hardness increased sharply with ordering and then decreased rapidly after reaching its peak value,due to the dominance of the discontinuous precipitation ***,the DO_(22)ordered phase did not appear during the ageing of Cu-15Ni-8Sn-1Al alloy,and a Ni_(3)(Al_(x),Sn_(1-x))intermetallic compound with L1_(2)structure was formed,consuming Ni and Sn atoms,thereby significantly suppressing the discontinuous precipitation reaction and improving the stability during prolonged *** tensile strength(yield strength)of Cu-15Ni-8Sn and Cu-15Ni-8Sn-1Al alloys at peak hardness were 855(755)and 936 MPa(892 MPa),respectively,and their main strengthening mechanisms were solid solution strengthening and precipitation *** addition of 1 wt%Al effectively improved the precipitation strengthening effect of Cu-Ni-Sn alloys but severely decreased the ductility.

关键词： Cu-15Ni-8Sn Al addition Precipitation sequence Strengthening mechanism

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Silver dissolution in a novel leaching system: Reaction kinetics study

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International Journal of Minerals,Metallurgy and Materials 2019年第2期26卷 168-177页

作者： Li Xiao Pei-wei Han Yong-liang Wang Guo-yan Fu Zhi Sun shu-feng Ye State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences

Effective silver recovery is usually restricted by either environmental pollution or high recovery costs. To tackle the issues, this study introduces a novel method for the effective recovery of silver by utilizing the alkaline sodium thiosulfate-potassium ferricyanide leaching system. The reaction kinetics of silver dissolution in this system was investigated via the rotating disk electrode technology. The influences of important parameters, including the rotation speed, sodium thiosulfate concentration, potassium ferricyanide concentration, and temperature, on the silver dissolution rate were systematically investigated. The activation energy was measured to be 17.96 kJ·mol^(-1) when the silver dissolution was controlled by a diffusion process. When the silver dissolution was in the region of mixed control, the reaction orders of ferricyanide and thiosulfate were found to be 0.57 and 0.19, respectively, and the reaction orders of ferricyanide and thiosulfate were 0.55 and 0.22, respectively, when the silver dissolution was controlled by surface reaction. This study has great potential for the development of an environmentally friendly silver recovery process from end-of-life products.

关键词： silver recovery thiosulfate ferricyanide dissolution kinetics non-cyanide

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Azobenzene‑Based Solar Thermal Fuels:A Review

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Nano-Micro Letters 2022年第8期14卷 232-268页

作者： Bo Zhang Yiyu feng wei feng School of Materials Science and Engineering Tianjin UniversityTianjin 300350People’s Republic of China Tianjin Key Laboratory of Composite and Functional Materials Tianjin 300350People’s Republic of China Key Laboratory of Materials Processing and Mold Ministry of EducationZhengzhou UniversityZhengzhou 450002People’s Republic of China

The energy storage mechanism of azobenzene is based on the transformation of molecular cis and trans isomerization,while NBD/QC,DHA/VHF,and fulvalene dimetal complexes realize the energy storage function by changing the molecular *** as“molecular batteries,”they can exhibit excellent charging and discharging behavior by converting between trans and cis isomers or changing molecular structure upon absorption of ultraviolet *** properties determining the performance of STFs are stored energy,energy density,half-life,and solar energy conversion *** review is aiming to provide a comprehensive and authoritative overview on the recent advancements of azobenzene molecular photoswitch system in STFs fields,including derivatives and carbon nano-templates,which is emphasized for its attractive *** the energy storage performance of Azo-STFs has already reached the level of commercial lithium batteries,the cycling capability and controllable release of energy still need to be further *** this,some potential solutions to the cycle performance are proposed,and the methods of azobenzene controllable energy release are ***,energy stored by STFs can be released in the form of mechanical energy,which in turn can also promote the release of thermal energy from STFs,implying that there could be a relationship between mechanical and thermal energy in Azo-STFs,providing a potential direction for further research on Azo-STFs.

关键词： Azobenzene Solar thermal fuels Nanocarbon template Controllable energy release Phase change materials

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Optimization of electrical parameters for micro-arc oxidation of zirconium hydride alloy

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Rare Metals 2022年第7期41卷 2324-2330页

作者： Zhi-Gang Wang wei-Dong Chen shu-Fang Yan Xiu-Juan Fan feng Guo Zhi-Gao Xu College of Materials and Engineering Inner Mongolia University of TechnologyHohhot 010051China Division of Mineral Resources Metallurgy and MaterialsGeneral Research Institute for Nonferrous MetalsBeijing 100088China Key Laboratory for Green Chemical Process of Ministry of Education Wuhan Institute of TechnologyWuhan 430073China

The present work aims to present the micro-arc oxidation(MAO)zirconia coating with superior compact-ness and moderate thickness on zirconium *** experiments were designed according to L16(44)orthog-onal array to optimize electrical parameters(frequency,negative voltage,positive voltage and MAO time),with four levels of each *** optimized value was pre-dicted and verified by the confirmation *** anti-permeation effect was tested by means of vacuum dehydrogenation *** optimized coating parameters are listed as follows:treating time of 25 min,frequency of 200 Hz,negative voltage of 150 V and pos-itive voltage of 380 *** results show that the optimized coating exhibits the highest compactness of 0.3705 mg·μm^(-1).This dense coating significantly enhan-ces the hydrogen anti-permeation effects,and the PRF value is improved by nearly 13 times in contrast with that of uncoated ZrH_(1.8).

关键词： coating alloy zirconium

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Hydrodynamic simulation of chaotic dynamics in InGaAs oscillator in terahertz region

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Chinese Physics B 2020年第4期29卷 94-97页

作者： wei feng Department of Physics Jiangsu UniversityZhenjiang 212013China

Hydrodynamic calculations of the chaotic behaviors in n^+nn^+In0.53Ga0.47As devices biased in terahertz(THz)electric field have been carried *** different transport characteristics have been carefully investigated by tuning the n-region parameters and the applied ac *** oscillatory mode is found to transit between synchronization and chaos,as verified by the first return *** transitions result from the mixture of the dc induced oscillation and the one driven by the ac *** findings will give further and thorough understanding of electron transport in In0.53Ga0.47As terahertz oscillator,which is a promising solid-state THz source.

关键词： terahertz chaotic current oscillation

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Treatment of tannery wastewater by electrocoagulation

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Journal of Environmental Sciences 2007年第12期19卷 1409-1415页

作者： feng Jing-wei SUN Ya-bing ZHENG Zheng ZHANG Ji-biao LI shu TIAN Yuan-chun State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210093 China

Treatment of tannery wastewater by electrocoagulation with low cell current （≤ 1A） and soluble electrodes （mild steel electrodes and aluminum electrodes） was studied. Compared with aluminum electrodes, mild steel electrodes were more effective for the removal of sulfide, with a removal efficiency of over 90%. But during the treatment process, black color precipitate typical to iron（Ⅱ） sulfides was produced. While aluminum electrodes were effective to eliminate the colority of the effluent, the removal efficiency of sulfide was lower than 12%. The mechanisms of the removal of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority with the two soluble electrodes （mild steel and aluminum electrodes） were discussed in detail. In order to exert the predominance of diffenent types of electrodes, the tannery wastewater was treated using mild steel electrodes first followed by the filter and finally by the aluminum electrodes, the elimination rates of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority were 68.0%, 43.1%, 55.1%, 96.7% and 84.3%, respectively, with the initial concentrations 2413.1 mg/L, 223.4 mg/L, 1000.4 mg/L, 112.3 mg/L and 256 dilution times, respectively. The absorbance spectra and energy consumption during electrocoagulation process were also discussed.

关键词： tannery wastewater electrocoagulation mild steel electrodes aluminum electrodes

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Utilization of gold-bearing and iron-rich pyrite cinder via a chlorination–volatilization process

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International Journal of Minerals,Metallurgy and Materials 2017年第11期24卷 1241-1250页

作者： Jian Ding Pei-wei Han Cui-cui Lü Peng Qian shu-feng Ye Yun-fa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

The chlorination-volatilization process has been adopted to make full use of gold-bearing and iron-rich pyrite cinder. However, problems of low recovery rate, pulverization of pellets, and ring formation have been encountered during the industrialization of this process. The effects of various parameters on the volatilization rates of valuable metals and on the compressive strength of roasted pellets were investigated in this paper. The parameters include the CaCl_2 dosage, heating temperature, and holding time. The results show that heating temperature is the most important parameter for the recovery of target metals. More CaCl_2 was needed for the recovery of zinc than for the recovery of gold, silver, and lead. CaCl_2 started to react with sulfides/SO_2/SiO_2 at temperatures below the melting point of CaCl_2 to generate Cl_2/HCl. Gaseous CaCl_2 was formed at higher temperatures and could react with any of the components. The compressive strength of roasted CaCl_2-bearing pellets first decreased slowly with increasing temperature at temperatures lower than 873 K, which could result in the pulverization of pellets during heating. Their compressive strength increased dramatically with increasing temperature at temperatures greater than 1273 K. Certain quantities of CaCl_2 and Fe(Ⅱ) could improve the compressive strength of the roasted pellets; however, the addition of excessive CaCl_2 decreased the compressive strength of pellets.

关键词： pyrite cinder gold chlorination oxidized pellets compressive strength

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Terahertz Current Oscillation in Wurtzite InN

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Chinese Physics Letters 2012年第1期29卷 231-234页

作者： feng wei Department of Physics Jiangsu UniversityZhenjiang 212013

Current self-oscillation in doped n+nn+wurtzite InN diodes driven by a dc electric field is theoretically investigated by solving the time-dependent drift-diffusion *** self-oscillation is associated with the negative differential mobility effect in the highly non-parabolic conduction band of InN.A detailed analysis of the dependence of current oscillations on the doping concentration and the applied electric field is *** current oscillation frequencies can reach up to the terahertz(THz)*** n^(+)nn^(+)InN self-oscillating diode may be a promising candidate for THz generation,and the calculation results may guide the design of the devices.

关键词： oscillation diodes diode

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Gradient sparsification for efficient wireless federated learning with differential privacy

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Science China(Information Sciences) 2024年第4期67卷 272-288页

作者： Kang wei Jun LI Chuan MA Ming DING feng shu Haitao ZHAO Wen CHEN Hongbo ZHU School of Electronic and Optical Engineering Nanjing University of Science and Technology Zhejiang Lab Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of Education Data61 Commonwealth Scientific and Industrial Research Organisation School of Information and Communication Engineering Hainan University School of Communications and Information Engineering Nanjing University of Posts and Telecommunications School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Federated learning(FL) enables distributed clients to collaboratively train a machine learning model without sharing raw data with each other. However, it suffers from the leakage of private information from uploading models. In addition, as the model size grows, the training latency increases due to the limited transmission bandwidth and model performance degradation while using differential privacy(DP)protection. In this paper, we propose a gradient sparsification empowered FL framework with DP over wireless channels, to improve training efficiency without sacrificing convergence performance. Specifically, we first design a random sparsification algorithm to retain a fraction of the gradient elements in each client’s local model, thereby mitigating the performance degradation induced by DP and reducing the number of transmission parameters over wireless channels. Then, we analyze the convergence bound of the proposed algorithm, by modeling a non-convex FL problem. Next, we formulate a time-sequential stochastic optimization problem for minimizing the developed convergence bound, under the constraints of transmit power, the average transmitting delay, as well as the client’s DP requirement. Utilizing the Lyapunov drift-plus-penalty framework, we develop an analytical solution to the optimization problem. Extensive experiments have been implemented on three real-life datasets to demonstrate the effectiveness of our proposed algorithm. We show that our proposed algorithms can fully exploit the interworking between communication and computation to outperform the baselines, i.e., random scheduling, round robin, and delay-minimization algorithms.

关键词： federated learning differential privacy gradient sparsification Lyapunov drift convergence analysis

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Output Tracking for One-Dimensional Wave Equation with Non-Collocated Control and Output Configuration

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Journal of Systems Science & Complexity 2020年第5期33卷 1469-1484页

作者： wei Jing feng Hongyinping School of Mathematical Sciences Shanxi UniversityTaiyuan 030006China

This paper considers output tracking for a one-dimensional wave equation with general disturbance which includes both internal nonlinear uncertainty and external *** performance output is non-collocated to the *** disturbance is estimated by an essentially extended state observer from active disturbance rejection control and the difficulty caused by the non-collocated configuration of control and output is overcome by a proper trajectory *** output feedback law is proposed to make the tracking error be convergent to zero exponentially as time goes to *** the same time,all states of the closed-loop system are shown to be uniformly *** simulation is also presented to validate the theoretical results.

关键词： Disturbance estimation output feedback output tracking wave equation

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