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Synergistic etching and intercalation enables ultrathin Ti_(3)C_(2)T_(x)and Nb_(2)CT_(x)MXene nanosheets

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Rare Metals 2023年第4期42卷 1175-1185页

作者： Qian-Qian Xiong Tahir Muhmood Cheng-xiao Zhao Jing-San xu xiao-fei Yang College of Science Nanjing Forestry UniversityNanjing210037China School of Chemistry and Physics Science and Engineering FacultyQueensland University of TechnologyBrisbaneQLD4001Australia

Transition metal-containing MXene has shown great potential in the promising research fields,and its performance strongly depends on the composition,structure,dimension,and surface ***,rational design and controllable synthesis of ultrathin two-dimensional(2D)MXene nanosheets with uniform surface terminations are of great ***,the use of 2D MXene,particularly in solar-powered photocatalysis and electrocatalysis,is restricted by the formation of thick,multi-layered MXene flakes with a small interlayer spacing produced from the conventional hydrofluoric acid(HF)etching *** this work,we report a few-layer MXene nanosheets by solely employing a mixture of lithium fluoride and hydrochloric acid as the etching *** etching and intercalation technique endows MXene with ultrathin 2D nanostructures;moreover,the use of fluoride salt,rather than harmful HF,offers a safer and environmentally-friendly synthetic route for scalable green production of 2D *** the obtained Ti_(3)C_(2)T_(x)and Nb_(2)CT_(x)nanosheets show a highly efficient photoelectrochemical performance superior to highly stacked MXene *** work highlights a mild,simultaneous etching and delamination strategy for the development of high quality of 2D MXene nanosheets.

关键词： MXene Electrocatalysis Hydrogen evolution reaction(HER) Two-dimensional(2D)nanomaterials

Burden of mental disorders and risk factors in the Western Pacific region from 1990 to 2021

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World Journal of Psychiatry 2025年第1期15卷 93-105页

作者： Ya-Xin xu xiao-xuan Niu Wen-Chang Jia Jing Wen xue-Lin Cheng Yan Han Ming-Hui Peng Jing Zhou Yao Liu Sun-Fang Jiang xiao-Pan Li Department of Health Management Centre Zhongshan HospitalFudan UniversityShanghai 200030China Department of General Practice Zhongshan HospitalFudan UniversityShanghai 200030China Department of Nutrition Zhongshan HospitalFudan UniversityShanghai 200032China School of Public Health Fudan UniversityShanghai 200032China

BACKGROUND The burden of mental disorders(MD)in the Western Pacific Region(WPR)re-mains a critical public health concern,with substantial variations across demogra-phics and *** To analyze the burden of MD in the WPR from 1990 to 2021,along with associated risk factors,to reveal changing trends and emerging *** We used data from the Global Burden of Disease 2021,analyzing prevalence,incidence,and disability-adjusted life years(DALYs)of MD from 1990 to *** methods included age-standardisation and uncertainty analysis to address variations in population structure and data *** Between 1990 and 2021,the prevalence of MD rose from 174.40 million cases[95%uncertainty interval(UI):160.17-189.84]to 234.90 million cases(95%UI:219.04-252.50),with corresponding DALYs increasing from 22.8 million(95%UI:17.22-28.79)to 32.07 million(95%UI:24.50-40.68).During this period,the burden of MD shifted towards older age *** and anxiety disorders were predominant,with females showing higher DALYs for depressive and anxiety disorders,and males more affected by conduct disorders,attention-deficit hyperactivity disorder,and autism spectrum ***,New Zealand,and Malaysia reported the highest burdens,whereas Vietnam,China,and Brunei Darussalam reported the ***,childhood sexual abuse and bullying,and intimate partner violence emerged as significant risk *** This study highlights the significant burden of MD in the WPR,with variations by age,gender,and *** coronavirus disease 2019 pandemic has exacerbated the situation,emphasizing the need for a coordinated response.

关键词： Mental disorders Western pacific region Global Burden of Disease Risk factors Disability-adjusted life years

A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of thin-walled structural components

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Frontiers of Mechanical Engineering 2022年第3期17卷 195-208页

作者： Long BAI fei xu xiao CHEN Xin SU Fuyao LAI Jianfeng xu State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Southwest Institution of Electronic Technology Chengdu610036China

The use of artificial intelligence to process sensor data and predict the dimensional accuracy of machined parts is of great interest to the manufacturing community and can facilitate the intelligent production of many key engineering *** this study,we develop a predictive model of the dimensional accuracy for precision milling of thin-walled structural *** aim is to classify three typical features of a structural component—squares,slots,and holes—into various categories based on their dimensional errors(i.e.,“high precision,”“pass,”and“unqualified”).Two different types of classification schemes have been considered in this study:those that perform feature extraction by using the convolutional neural networks and those based on an explicit feature extraction *** classification accuracy of the popular machine learning methods has been evaluated in comparison with the proposed deep learning *** on the experimental data collected during the milling experiments,the proposed model proved to be capable of predicting dimensional accuracy using cutting parameters(i.e.,“static features”)and cutting-force data(i.e.,“dynamic features”).The average classification accuracy obtained using the proposed deep learning model was 9.55%higher than the best machine learning algorithm considered in this ***,the robustness of the hybrid model has been studied by considering the white Gaussian and coherent ***,the proposed hybrid model provides an efficient way of fusing different sources of process data and can be adopted for prediction of the machining quality in noisy environments.

关键词： precision milling dimensional accuracy cutting force convolutional neural networks coherent noise

Experimental study on the moving characteristics of fine grains in wide grading unconsolidated soil under heavy rainfall

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Journal of Mountain Science 2017年第3期14卷 417-431页

作者： CUI Yi-fei ZHOU xiao-jun GUO Chao-xu Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClear Water BayHong KongChina China Merchants Chongqing Communications Research&Design Institute Chongqing 400067China Fujian Academy of Building Research Pujian Key Laboratory of Green Building TechnologyFuzhou 350025China Fuzhou University Fuzhou 350108China

The initiation mechanism of debris flow is regarded as the key step in understanding the debrisflow processes of occurrence, development and damage. Moreover, migration, accumulation and blocking effects of fine particles in soil will lead to soil failure and then develop into debris flow. Based on this hypothesis and considering the three factors of slope gradient, rainfall duration and rainfall intensity, 16 flume experiments were designed using the method of orthogonal design and completed in a laboratory. Particle composition changes in slope toe, volumetric water content, fine particle movement characteristics and soil failure mechanism were analyzed and understood as follows: the soil has complex, random and unstable structures, which causes remarkable pore characteristics of poor connectivity, non-uniformity and easy variation. The major factors that influence fine particle migration are rainfall intensity and slope. Rainfall intensity dominates particle movement, whereby high intensity rainfall induces a large number of mass movement and sharp fluctuation, causing more fine particles to accumulate at the steep slope toe. The slope toe plays an important role in water collection and fine particleaccumulation. Both fine particle migration and coarse particle movement appears similar fluctuation. Fine particle migration is interrupted in unconnected pores, causing pore blockage and fine particle accumulation, which then leads to the formation of a weak layer and further soil failure or collapses. Fine particle movement also causes debris flow formation in two ways: movement on the soil surface and migration inside the soil. The results verify the hypothesis that the function of fine particle migration in soil failure process is conducive for further understanding the formation mechanism of soil failure and debris flow initiation.

关键词： Wide grading unconsolidated soil Fine particle migration Soil failure Landslide Debris flow initiation Flume test Heavy rainfall

Effect of K2TiO(C2O4)2 Addition in Electrolyte on the Microstructure and Tribological Behavior of Micro-Arc Oxidation Coatings on Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第11期30卷 1109-1118页

作者： Jian-Li Wang Wei Yang Da-Peng xu xiao-fei Yao School of Materials Science and Chemical Engineering Xi'an Technological University Xi'an 710021 China

Micro-arc oxidation （MAO） coatings with different concentrations of K2TiO（C2O4）2 in the sodium silicate base electrolyte were prepared on 6061 aluminum alloy with the aim of promoting a better understanding of the formation mechanisms and tribological behaviors of the coatings. Scanning electron microscopy （SEM） assisted with energy-dis- persive X-ray spectroscopy （EDS）, X-ray photoelectron spectroscopy （XPS） and friction test were employed to charac- terize the MAO processes and microstructure of the resultant coatings. Results showed that the composition and microstructure of the coatings were significantly affected by the addition of KETiO（CaO4）2. A sealing microstructure of MAO coating was obtained with the addition of K2TiO（C2O4）2. Ti element from K2TiO（C2O4）2 was only absorbed into the defects of micropores under surface energy in the early stage, while in the later stage, Ti element was predominant in the micropores and distributed on the coatings under plasma discharge to form TiO2. It was demonstrated that Ti and Si elements from the electrolyte could interact with each other during the MAO process and the interaction mechanism was systematically analyzed. Wear resistance of the MAO coatings with K2TiO（C2O4）2 addition was significantly improved compared with that of the MAO coatings without K2TiO（C2O4）2 addition.

关键词： Aluminum alloy Micro-arc oxidation K2TiO(C2O4)2 Coating formation mechanism Tribological behavior

The near-Surface Region of Cubic Boron Nitride Single Crystal from the Li3N-hBN System

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Chinese Physics Letters 2014年第4期31卷 182-184页

作者： GUO xiao-fei xu Bin WEN Zhen-Xing FAN xiao-Hong TIAN Bin School of Materials Science and Engineering Shandong University Jinan 250061 School of Materials Science and Engineering Shandong Jianzhu University Jinan 250101

Cubic boron nitride single crystals are synthesized with lithium nitride as a catalyst under high pressure and high temperature. The main phases in the near-surface region, which around the single crystal are determined as a mixture of hexagonal boron nitride （hBN）, cubic boron nitride （cBN） and lithium boron nitride （Li3BN2）. High resolution transmission electron microscopy examinations show that there exist lots of nanometer-sized cubic boron nitride nuclei in this region. The interface phase structures of cubic boron nitride crystal and its near-surface region are investigated by means of transmission electron microscopy. The growth mechanism of cubic boron nitride crystal is analyzed briefly. It is supposed that LisBN2 impels the direct conversion of hBN to cBN as a real catalyst, and cBN is homogeneously nucleated in the molten state under high pressure and high temperature.

关键词： System The near-Surface near-surface

A Parametric Survey of the CME Triggering Process by Numerical Simulations

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Chinese Journal of Astronomy and Astrophysics 2005年第6期5卷 636-644页

作者： xiao-Yan xu Peng-fei Chen Cheng Fang Department of Astronomy Nanjing University Nanjing 210093

Observations indicate that solar coronal mass ejections （CMEs） are closely associated with reconnection-favored flux emergence, which was explained in the emerging flux trigger mechanism for CMEs by Chen ＆ Shibata based on numerical simulations. We present a parametric survey of the triggering agent： its polarity orientation, position, and the amount of the unsigned flux. The results suggest that whether a CME can be triggered depends on both the amount and location of the emerging flux, in addition to its polarity orientation. A diagram is presented to show the eruption and non-eruption regimes in the parameter space. The work is aimed at providing useful information for the space weather forecast.

关键词： Sun coronal mass ejections (CMEs)-Sun filaments

A Novel Conceptual Telescopic Positioning Pile for VLFS Deployed in Shallow Water:Structure Design

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China Ocean Engineering 2020年第4期34卷 526-536页

作者： xu Sheng-wen LIU xiao-lei WANG xue-feng DENG Yan-fei State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration(CISSE) Shanghai 200240China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China CIMC Offshore Co.Ltd Shenzhen 518000China

A conceptual design of using novel telescopic piles to position a multi-modular very large floating structure(VLFS),which is supposed to be severed as a movable floating airport,is *** telescopic piles can automatically plug in the soil to resist the environmental loads and pull out from the soil to evacuate or move on to the next operational *** feasibility demonstration of the conceptual design includes two parts:function verification and structure *** the latter part of the conceptual design,a time-domain structural analysis is firstly conducted by using Abaqus *** simulation results suggest that the preliminary structure scheme is not optimum due to the insufficient structure utilization,although both structure safety of the piles and positioning accuracy are *** realize a cost reduction of construction and installation,a Genetic Algorithm-Finite Element Analysis(GA-FEA)method is employed to perform structural *** optimization,31 percent of the weight of each pile is reduced and higher structure utilization is *** difference of the self-weight and allowable buoyancy of a single module(SMOD)of a semisubmersible-type VLFS is much larger than the weight of the *** with the function verification in our previous work,the conceptual design of using the novel telescopic pile to position VLFS is demonstrated to be feasible.

关键词： novel telescopic positioning pile feasibility demonstration structural optimization very large floating structure(VLFS)

Nonlinear Absorption and Refraction in Multilevel Organic Molecular System

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Chinese Physics Letters 2000年第8期17卷 574-576页

作者： LI Chun-fei DENG xiao-xu WANG Yu-xiao Department of Physics Harbin Institute of TechnologyHarbin 150001

The nonlinear absorption and refraction in a multilevel organic molecular system is described by using the density matrix *** total absorptive coefficient of the system in the low-density case is equal to a linear sum of contributions from each energy ***,the total refractive index is equal to a linear sum of contributions from each energy level plus the refractive index of the *** absorption coefficient or refractive index due to each level is proportional to the population of that level,where the constant of proportionality is called the absorption cross-section or the refraction volume,*** relation between the absorption cross-section and the refraction volume for each level is also given.

关键词： theory. refraction absorption