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Atomic-level insights into the initial oxidation mechanism of high-entropy diborides by first-principles calculations

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Journal of Materiomics 2024年第2期10卷 423-430页

作者： yiwen liu Hulei Yu Hong Meng Yanhui Chu School of Materials Science and Engineering South China University of TechnologyGuangzhou510641China

Understanding the initial oxidation mechanism is critical for studying the oxidation resistance of high-entropy ***,related studies are ***,the initial oxidation mechanism of(Zr_(0.25)Ti_(0.25)Nb_(0.25)Ta_(0.25))B_(2)high-entropy diborides(HEB_(2)-1)is investigated by first-principles calculations at the atomic *** employing the two-region model method,the most stable surface of HEB_(2)-1 is determined to be(1120)*** dissociative adsorption process of the oxygen molecule on the HEB_(2)-1-(1120)surface is predicted to proceed spontaneously,where OeO bond breaks and each oxygen atom is chemisorbed on the most preferable hollow *** adsorption energy and the diffusion barrier of the oxygen atom on the(1120)surface of HEB_(2)-1 are in the vicinity of the average level of the cor-responding four individual *** addition,ab initio molecular dynamics simulations indicate a high initial oxidation resistance of HEB_(2)-1 at 1000 *** results are beneficial to further designing the high-entropy diborides with excellent oxidation resistance.

关键词： High-entropy diborides Oxidation First-principles calculations

A thermally crosslinked ion-gel gated artificial synapse

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Chinese Chemical Letters 2023年第3期34卷 557-560页

作者： yiwen liu Yongfei Wang Xiao Li Zhizhi Hu Key Laboratory for Functional Materials School of Chemical EngineeringUniversity of Science and Technology LiaoningAnshan 114051China

We demonstrate a synaptic transistor that uses a thermally crosslinked three-dimensional network to accommodate ionic liquid to form an ion gel layer. The synaptic transistor successfully emulated important synaptic plasticity, such as paired-pulse facilitation, spike-number dependent plasticity, spike-voltage dependent plasticity, and spike-rate dependent plasticity;these responses imply successful use of the ion gel. Moreover, the device realized “OR” and “AND” logic operations, and high-pass filtering behavior. Energy consumption of the device can be reduced to sub-femtojoule level, which is below that of biological synapses. Compared with traditional physical cross-linking using block copolymers, this method provides a facile strategy to prepare ion gels with tunable properties by altering the polymers and crosslinkers,and to enormously reduce the price by replacing expensive block copolymers or eliminating additional synthesis processes. This report provides a versatile strategy for design of synaptic transistors and their applications in neuromorphic electronics.

关键词： Synaptic transistor Thermal cross-linking Ion gel Logic operations High-pass filtering

Spatiotemporal variability of rain-on-snow events in the arid region of Northwest China

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Journal of Arid Land 2024年第4期16卷 483-499页

作者： YANG Zhiwei CHEN Rensheng liu Zhangwen ZHAO Yanni liu yiwen WU Wentong Qilian Alpine Ecology and Hydrology Research Station Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Rain-on-snow(ROS)events involve rainfall on snow surfaces,and the occurrence of ROS events can exacerbate water scarcity and ecosystem vulnerability in the arid region of Northwest China(ARNC).In this study,using daily snow depth data and daily meteorological data from 68 meteorological stations provided by the China Meteorological Administration National Meteorological Information Centre,we investigated the spatiotemporal variability of ROS events in the ARNC from 1978 to 2015 and examined the factors affecting these events and possible changes of future ROS events in the *** results showed that ROS events in the ARNC mainly occurred from October to May of the following year and were largely distributed in the Qilian Mountains,Tianshan Mountains,Ili River Valley,Tacheng Prefecture,and Altay Prefecture,with the Ili River Valley,Tacheng City,and Altay Mountains exhibiting the most *** on the intensity of ROS events,the areas with the highest risk of flooding resulting from ROS events in the ARNC were the Tianshan Mountains,Ili River Valley,Tacheng City,and Altay *** number and intensity of ROS events in the ARNC largely increased from 1978 to 2015,mainly influenced by air temperature and the number of rainfall ***,due to the snowpack abundance in areas experiencing frequent ROS events in the ARNC,snowpack changes exerted slight impact on ROS events,which is a temporary ***,elevation imposed lesser impact on ROS events in the ARNC than other *** the ARNC,the start time of rainfall and the end time of snowpack gradually advanced from the spring of the current year to the winter of the previous year,while the end time of rainfall and the start time of snowpack gradually delayed from autumn to *** may lead to more ROS events in winter in the *** results could provide a sound basis for managing water resources and mitigating related disasters caused by ROS events in the ARNC.

关键词： rain-on-snow events snowpack snowmelt climate change Spearman's rank correlation arid region of Northwest China

Research on the method of construction disturbance zoning for shield tunnel approaching to urban structures

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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1663-1679页

作者： Ziyang ZHOU Fukang GUO Jianzhong NI Kun FENG Jingxuan ZHANG yiwen liu Key Laboratory of Transportation Tunnel Engineering of Ministry of Education Southwest Jiaotong UniversityChengdu 610031China Hangzhou Fuyang City Construction Investment Group co. Ltd.Hangzhou 310000China

This paper presents a calculation method that evaluates the extent of disturbance based on structural safety ***,it summarizes the assessment methods for construction disturbance zones in shield tunneling near pile foundations,urban ground structures,and underground ***,taking the construction of the Chengdu Jinxiu Tunnel under bridges and urban pipelines as the engineering background,a study on the disturbance zoning of adjacent structures was *** most intense disturbance occurs within one week of the tunnel underpass process,and it has a significant impact within a range of two times the tunnel diameter along the tunnel *** bridge pile and bridge deck experience less disturbance from tunnel approaching construction,with a maximum disturbance zone characterized as medium *** the other hand,underground pipelines are subjected to more significant disturbances from tunnel construction,with a maximum disturbance zone classified as strong *** implementation of“bridge pile sleeve valve pipe grouting&underground pipeline ground grouting&tunnel advance grouting”in the field effectively limits the vertical settlement of bridges and pipelines,resulting in a decrease of approximately 0.1 in disturbance level for the *** disturbance zoning method can assess tunnel disturbance with structures,identify high-risk interference locations,and facilitate targeted design reinforcement solutions.

关键词： shield tunnel approaching construction field monitoring disturbance zoning method

Preparation and Arc Erosion Resistance of C_f/Cu Composite by Vacuum Melting Infiltration

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Journal of Wuhan University of Technology(Materials Science) 2014年第5期29卷 1039-1043页

作者：张华煜 liu yiwen ZHAO Xianling LUAN Xingang College of Material Science and Engineering Taiyuan University of Science and Technology Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical University

Cf/Cu composite was prepared by vacuum melting infiltration. Ti and Cr were doped to the Cu alloy to improve the wettability between Cu and carbon. The microstrueture was investigated by XRD, SEM and EDS. The arc erosion rate of Cf/Cu composite was investigated in vacuum. The results showed that the Ti and Cr could improve the wettability between Cu and C/C preform and the infiltration ability of Cu into C/ C preform greatly. A TiC interface formed between the fibers and matrix. The good bonding between the fiber and matrix guaranteed that part of the Cu matrix can still be bonded on the fibers even when the material was exposed to the plasma. Consequently, the carbon fibers were protected from the erosion. In comparison, Cu was completely consumed by the arc erosion. Hence, the graphite was eroded and presented a cauliflower-like morphology. Therefore, the prepared C/Cu bad better ability to resist the arc erosion, compared with common Cu-C material.

关键词： Cf/Cu composite vacuum melting infiltration arc erosion

State of charge estimation by square root cubature particle filter approach with fractional order model of lithium-ion battery

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Science China(Technological Sciences) 2022年第8期65卷 1760-1771页

作者： liu yiwen SHI Qin WEI YuJiang HE ZeJia HU XiaoSong HE Lin School of Automotive and Transportation Engineering Hefei University of TechnologyHefei 230009China The State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China Laboratory of Automotive Intelligence and Electrification Hefei University of TechnologyHefei 230009China

In this paper, a square root cubature particle filter approach was designed to estimate the state of charge of lithium-ion battery,which not only enhanced the numerical stability and guaranteed positive definiteness of the state covariance, but also increased accuracy and decreased computation quantity. Due to the fractional characteristics of the battery capacitance, a fractional order model was used to formulate the lithium-ion battery. Considering the high accuracy and easy convergence, a particle swarm optimization algorithm was utilized to identify the model parameters. The above-mentioned approach was modelled and translated into C code, which was downloaded into battery control unit of battery management system for experimental validation. Two kinds of dynamic cycles were utilized to validate the proposed approach at different temperatures, where both unscent Kalman filter and cubature Kalman filter were compared with the proposed approach. Experimental results indicate that the proposed approach has better accuracy and robustness, and fractional order model is more accurate than integer order ***, the square root cubature particle filter with fractional order model of lithium-ion battery is a good candidate to estimate the state of charge.

关键词： battery management system integer order model particle filter unscent kalman filter cubature Kalman filter

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Cu-substituted nickel hexacyanoferrate with tunable reaction potentials for superior ammonium ion storage

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Journal of Materials Science & Technology 2024年第2期169卷 19-27页

作者： Leiyu Fan Guangchang Shu yiwen liu Haoxiang Yu Lei Yan Liyuan Zhang Jie Shu School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China

In this work,a variety of Cu_(x)Ni_(2-x)Fe(CN)_(6)(x=0,0.4,0.8,1.2,1.6,2)cathodes for ammonium ion batteries are prepared and their electrochemical performances are *** the introduction of copper in nickel hexacyanoferrate,the electrochemical performance varies without changing the structure of nickel *** increase of Cu content in nickel hexacyanoferrate leads to the enhancement of reaction potential and *** results suggest that the substitution of Cu for Ni has a positive effect on improving the cycling stability and rate capacity of nickel hexacyanoferrate when x in Cu_(x)Ni_(2-x)Fe(CN)_(6)is less than ***,Cu_(0.4)Ni_(1.6)Fe(CN)_(6)exhibits the best cycling per-formance(capacity retention of 97.54%at 0.3 C)and the highest rate capacity(41.4 mAh g^(-1)at 10 C)in Cu_(x)Ni_(2-x)Fe(CN)_(6).Additionally,the X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)tests also reveal that the structural evolution of Cu_(0.4)Ni_(1.6)Fe(CN)_(6)is highly reversible upon NH_(4)^(+)***,this work proposes a candidate material for ammoniumion batteries and offers a novel avenue for adjusting the operating potential of the material.

关键词： Nickel hexacyanoferrate Copper hexacyanoferrate NH_(4)^(+)storage Ammonium ion batteries Aqueous batteries

Evaluating the impact of sulfamethoxazole on hydrogen production during dark anaerobic sludge fermentation

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Frontiers of Environmental Science & Engineering 2023年第1期17卷 75-85页

作者： Tingting Zhu Zhongxian Su Wenxia Lai Jiazeng Ding Yufen Wang Yingxin Zhao yiwen liu School of Environmental Science and Engineering Tianjin UniversityTianjin 300072China

The impact of antibiotics on the environmental protection and sludge treatment fields has been widely *** recovery of hydrogen from waste activated sludge(WAS)has become an issue of great ***,few studies have focused on the impact of antibiotics present in WAS on hydrogen production during dark anaerobic *** explore the mechanisms,sulfamethoxazole(SMX)was chosen as a representative antibiotic to evaluate how SMX influenced hydrogen production during dark anaerobic fermentation of *** results demonstrated SMX promoted hydrogen *** increasing additions of SMX from 0 to 500 mg/kg TSS,the cumulative hydrogen production elevated from 8.07±0.37 to 11.89±0.19 mL/g VSS.A modified Gompertz model further verified that both the maximum potential of hydrogen production(Pm)and the maximum rate of hydrogen production(R_(m))were *** did not affected sludge solubilization,but promoted hydrolysis and acidification processes to produce more ***,the methanogenesis process was inhibited so that hydrogen consumption was *** community analysis further demonstrated that the introduction of SMX improved the abundance of hydrolysis bacteria and hydrogen-volatile fatty acids(VFAs)*** synergistically influenced hydrolysis,acidification and acetogenesis to facilitate the hydrogen production.

关键词： Sulfamethoxazole Hydrogen production Dark anaerobic fermentation Waste activated sludge

Cathode Erosion of Graphite and Cu/C Materials in Airarcs

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Journal of Wuhan University of Technology(Materials Science) 2012年第1期27卷 18-20页

作者： Zhang Chengyu Qiao Shengru liu yiwen Yang Zhimao Wang Yaping Yong Guo Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an710072China School of Science Xi’an Jiaotong UniversityXi’an710049China Department of Chemistry Datong UniversityDatong037000China

Cathode erosion of graphite and Cu/C was studied in direct current arcs, which were ignited between two electrodes comprised of two kinds of carbon materials and a tungsten anode in air. The arced zones on the cathode surface were investigated by a scanning electron microscope. Also, the cathode erosion rates of the investigated materials were measured. The results show that two distinct zone can be seen on both cathodes. The eroded area was located at the zone just opposite to the anode and surrounded by a white zone. The arced surface on the Cu/C containing 9.3 % Cu is rougher than that of the pure graphite. Many particles with various sizes distributed on the Cu/C. The vaporization of Cu can lower the surface temperature and reduce the cathode erosion. Therefore, the cathode erosion rate of the Cu/C is lower than that of the pure graphite.

关键词： Cu/C composite graphite air arc cathode erosion