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Anomalous{1012}tensile twinning and subsequent detwinning in a friction stir processed carbon fiber-reinforced Mg composite

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Journal of Magnesium and Alloys 2024年第4期12卷 1511-1517页

作者： Wei Zhao Zhihao Jiang Xiang wu Yujing Liu Haokun Yang Jun Wang Qi Liu xiaochun Liu Institute of Metals College of Materials Science and EngineeringChangsha University of Science&TechnologyChangsha 410114China Department of Mechanical Engineering City University of Hong KongHong KongChina Smart manufacturing division Hong Kong Productivity CouncilHong Kong SAR 999077China Institute for Frontier Materials Deakin UniversityGeelongVIC 3216Australia Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina

1.Main text Owing to their low density and high specific strength,magnesium alloys and magnesium-based composites have great potential as structure metal materials in applications where lightweight matters[1–4].Deformation twins[5],especially the{1012}tension twins(also called tensile or extension twins)with a low critical resolved shear stress(CRSS)[6],are commonly observed in Mg alloys.They can provide the much-needed deformation along the c-axis in their hcp structure resulting from the very few easily activated slip systems in this crystal structure[7].The tensile twinning activation usually follows the macroscopic Schmid factor law[2],i.e.,the twin variant with the highest Schmid factor occurs,and it only appears when its Schmid factor is positive.

关键词： friction deformation magnesium

Fault diagnosis of railway point machines based on wavelet transform and artificial immune algorithm

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Transportation Safety and Environment 2023年第4期5卷 117-126页

作者： xiaochun wu Weikang Yang Jianrong Cao School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070GansuChina China Railway Rolling Stock Corporation Qingdao Sifang Rolling Stock Research Institute Co. LtdQingdao 266000ShandongChina

Aiming at the current problems of high failure rate and low diagnostic efficiency of railway point machines(RPMs)in the railway industry,a short-time method of fault diagnosis is proposed.Considering the effect of noise on power signals in the data acquisition process of the railway centralized signaling monitoring(CSM)system,this study utilizes wavelet threshold denoising to eliminate interference.The results show that the accuracy of fault diagnosis can be improved by 4.4% after denoising the power signals.Then in order to attain a lighter weight and shorten the running time of the diagnosis model,Mallat wavelet decomposition and artificial immune algorithm are applied to RPM fault diagnosis.Finally,voluminous experiments using veritable power signals collected from CSM are introduced,which show that combining these methods can procure higher precision of RPMs and curtail fault diagnosis time.This substantiates the validity and feasibility of the presented approach.

关键词： railway point machines wavelet threshold denoising Mallat wavelet decomposition artificial immune algorithm

Study on risk assessment and factors ranking of the LTE-M communication system

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Transportation Safety and Environment 2023年第4期5卷 45-57页

作者： xiaochun wu Yu Gao Weichao Zheng School of Automation Electrical Engineering Lanzhou Jiaotong UniversityAnning West RoadLanzhou 730070GansuChina Communication Center Tianjin Rail Transit Operation Group Co.LtdNo.36Xuefu Industrial ParkTianjin 300000China

To assess the operational safety risk of long-term evolution for the metro(LTE-M)communication system more accurately,the guide maintenance strategy,the improved evidence theory and the multi-attribute ideal reality comparative analysis(MAIRCA)approaches are proposed.According to the features of LTE-M system,the risk evaluation system is established.The enhanced structural entropy weight method is used to obtain the weight.Furthermore,it is combined with nine-element fuzzy mathematics to transform the degree of membership,modifying the conflict and fusion rules to solve the confidence degree clashed problem of evidence theory.Then,the system risk grade assessment result is obtained.For the purpose of forming the ranking of indicator importance,the MAIRCA is introduced and the ranking is three-dimensional.The operational state of the metro line is used as the data source in various ways the obtained risk grade increased by 7.12%.It is verified that MAIRCA can be applied to the field of urban rail transit because it has based on the test and calculation.The results show that the method is effective;compared with others,the confidence degree of excellent stability and the ranking result of risk factors is reasonable.The influencing indicator with the highest importance is the'equipment failure rate".

关键词： long-term evolution for the metro(LTE-M)system operational safety risk assessment improved evidence theory multi-attribute ideal reality comparative analysis(MAIRCA)method

A Hierarchical Method for Locating the Interferometric Fringes of Celestial Sources in the Visibility Data

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Research in Astronomy and Astrophysics 2024年第3期24卷 110-128页

作者： Rong Ma Ruiqing Yan Hanshuai Cui xiaochun Cheng Jixia Li Fengquan wu Zongyao Yin Hao Wang Wenyi Zeng Xianchuan Yu School of Artificial Intelligence Beijing Normal UniversityBeijing 100875China Department of Computer Science Swansea UniversitySwanseaSA18ENUK National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

In source detection in the Tianlai project,locating the interferometric fringe in visibility data accurately will influence downstream tasks drastically,such as physical parameter estimation and weak source exploration.Considering that traditional locating methods are time-consuming and supervised methods require a great quantity of expensive labeled data,in this paper,we first investigate characteristics of interferometric fringes in the simulation and real scenario separately,and integrate an almost parameter-free unsupervised clustering method and seeding filling or eraser algorithm to propose a hierarchical plug and play method to improve location accuracy.Then,we apply our method to locate single and multiple sources’interferometric fringes in simulation data.Next,we apply our method to real data taken from the Tianlai radio telescope array.Finally,we compare with unsupervised methods that are state of the art.These results show that our method has robustness in different scenarios and can improve location measurement accuracy effectively.

关键词： methods data analysis-techniques image processing-techniques interferometric

Consensus on rapid screening for prodromal Alzheimer's disease in China

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General Psychiatry 2024年第1期37卷 1-16页

作者： Lin Huang Qinjie Li Yao Lu Fengfeng Pan Liang Cui Ying Wang Ya Miao Tianlu Chen Yatian Li Jingnan wu xiaochun Chen Jianping Jia Qihao Guo Department of Gerontology Shanghai Sixth People's Hospital Afiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina shanghai BestCovered ShanghaiChina ADepartment of Neurology Fujan Medical University Union HospitalFuzhouChina Department of Neurology National Clinical Research Center for Geriatric DiseasesBeijingChina

Alzheimer's disease(AD)is a common cause of dementia,characterised by cerebral amyloid-βdeposition,pathological tau and neurodegeneration.The prodromal stage of AD(pAD)refers to patients with mild cognitive impairment(MCl)and evidence of AD's pathology.At this stage,disease-modifying interventions should be used to prevent the progression to dementia.Given the inherent heterogeneity of MCl,more specific biomarkers are needed to elucidate the underlying AD's pathology.Although the uses of cerebrospinal fluid and positron emission tomography are widely accepted methods for detecting AD's pathology,their clinical applications are limited by their high costs and invasiveness,particularly in low-income areas in China.Therefore,to improve the early detection of Alzheimer's disease(AD)pathology through cost-effective screening methods,a panel of 45neurologists,psychiatrists andgerontologistswas invited to establish a formal consensus on the screening of pAD in China.The supportive evidence and grades of recommendations are based on a systematic literature review andfocus group discussion.National meetings were held to allow participants to review,vote and provide their expert opinions to reach a consensus.A majority(two-thirds)decision was used for questions for which consensus could not be reached.Recommended screening methods are presented in this publication,including neuropsychological assessment,peripheral biomarkers and brain imaging.In addition,a general workflow for Screening pAD in China is established,which will help clinicians identify individuals at high risk and determine therapeutic targets.

关键词： Alzheimer income screening

Scalable production of mesoporous titanium nanoparticles through sequential flash nanocomplexation

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Chinese Chemical Letters 2024年第4期35卷 303-309页

作者： Feng Cui Fangman Chen xiaochun Xie Chenyang Guo Kai Xiao Ziping wu Yinglu Chen Junna Lu Feixia Ruanb Chuanxu Cheng Chao Yang Dan Shao School of Biomedical Sciences and Engineering South China University of TechnologyGuangzhou International CampusGuangzhou 511442China Institutes for Life Sciences School of MedicineSouth China University of TechnologyGuangzhou 510006China School of Biology and Biological Engineering South China University of TechnologyGuangzhou 510006China Department of Orthopedics Academy of Orthopedics-Guangdong ProvinceOrthopedic Hospital of Guangdong ProvinceGuangdong Provincial Key Laboratory of Bone and Joint Degenerative DiseasesThe Third Affiliated Hospital of Southern Medical UniversityGuangzhou 510665China National Engineering Research Center for Tissue Restoration and Reconstruction South China University of TechnologyGuangzhou 510006China

Mesoporous titanium nanoparticles(MTNs) have emerged as an important porous semiconductor owning to their large surface area and unique electronic/optical properties. However, the fundamental research for rational manufacturing MTNs in a highly scalable manner remains a challenge. In this study, we report a two-step flash nanocomplexation(FNC) approach to large-scalable generate MTNs through the sequential combination of two multi-inlet vortex mixers. By optimizing the concentrated titanium precursor,polyethylene glycol(PEG)-functionalized silane amount and p H, we have been able to produce MTNs with small particle size(31.5 nm), larger surface area(416.9 m^(2)/g) and pore volume(0.59 cm^(3)/g). Different from the traditional MTNs bulk, FNC-produced MTNs exhibited well-controlled manner and exceptional photocatalytic and antibacterial properties. Importantly, the optimized MTNs outperformed commercial P25 not only in protecting ultraviolet A(UVA)-exposed skin, but also in treating P. aeruginosa-infected wound. We believe that the high controllability and scalability of sequential flash nanocomplexation method offers great opportunities in enhancing the performance of mesoporous titanium nanoparticles.

关键词： Mesoporous titanium nanoparticles Flash nanocomplexation Photocatalytic Antibacterial Sequential

Research on text fault recognition for on-board equipment of a C3 train control system based on an integrated XGBoost algorithm

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Transportation Safety and Environment 2023年第4期5卷 36-44页

作者： Lili Yue Luyue Liu Maoqing Li Baodi Xiao xiaochun wu School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070GansuChina Beijing Consen Traffic Technology Co. Ltd.Beijing 101318China

The robust guarantee of train control on-board equipment is inextricably linked to the safe functioning of a high-speed train.A fault diagnostic model of on-board equipment is built utilizing the integrated learning XGBoost(eXtreme Gradient Boosting)algorithm to help technicians assess the malfunction category of high-speed train control on-board equipment accurately and rapidly.The XGBoost algorithm iterates multiple decision tree models to improve the accuracy of fault diagnosis by lifting the predicted residual and adding regular terms.To begin,the text features were extracted using the improved TF-IDF(Term Frequency-Inverse Document Frequency)approach,and 24 fault feature words were chosen and converted into weight word vectors.Secondly,considering the imbalanced fault categories in the data set,the ADASYN(Adaptive Synthetic sampling)adaptive synthetically oversampling technique was used to synthesize a few category fault samples.Finally,the data samples were split into training and test sets based on the fault text data of CTCS-3train control on-board equipment recorded by Guangzhou Railway Group maintenance personnel.The XGBoost model was utilized to realize the automatic fault location of the test set after optimized parameter tuning through grid search.Compared with other methods,the evaluation index of the XGBoost model was significantly improved.The diagnostic accuracy reached 95.43%,which verifies the effectiveness of the method in text fault diagnosis.

关键词： vehicle on-board equipment unbalanced data sets text feature extraction XGBoost model fault diagnosis

Plasmonic nanostructures acting as a light-driven O_(2)-sensitive nitroreductase mimic for enhanced photochemical oxidation of para-aminothiophenol

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Nano Research 2023年第11期16卷 12697-12705页

作者： Xinshuang Gao Jia-jia Zheng Hanbo Li Rui Cai Xingfa Gao xiaochun wu CAS Key Laboratory of Standardization and Measurement for Nanotechnology National Center for Nanoscience and TechnologyBeijing 100190China Laboratory of Theoretical and Computational Nanoscience National Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Nanozymes,as a novel form of enzyme mimics,have garnered considerable interest.Despite overcoming the main disadvantages of their natural analogs,they still face challenges such as restricted mimic types and low substrate specificity.Herein,we introduce a reactive ligand modification strategy to diversify enzyme mimic types.Specifically,we have utilized helical plasmonic nanorods(HPNRs)modified with para-nitrothiophenol(4-NTP)to create an oxygen-sensitive nitroreductase(NTR)with light-controllability.HPNRs act as a light-adjustable source of nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate(NAD(P)H),providing photon-generated energetic electrons to adsorbed 4-NTP molecules.In the presence of O_(2),the activated 4-NTP transfers the captured electron to the adsorbed O_(2),mimicking the electron transfer process in its natural counterpart.This enhanced O_(2)activation notably boosts the oxidative coupling of para-aminothiophenol(4-ATP).Density functional theory(DFT)calculations reveal that hot electrons injected into the lowest unoccupied molecular orbital(LUMO)energy level of 4-NTP can be transferred to that of molecular oxygen.In conclusion,our findings underline the potential of the reactive ligand modification strategy in developing new types of enzyme reactions,which opens up promising avenues for the enhancement and diversification of nanozyme functionalities.

关键词： plasmonic nanostructure nanozyme nitroreductase para-nitrothiolphenol hot electron injection para-aminothiolphenol

Temperature-modulated inversion and switching of chiroptical responses in dynamic side-by-side oligomers of gold nanorods

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Nano Research 2023年第12期16卷 13392-13399页

作者： Hanbo Li Dejing Meng Chenqi Zhang Yinglu Ji Xinshuang Gao Zhijian Hu xiaochun wu CAS Key Laboratory of Standardization and Measurement for Nanotechnology National Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Herein,a new strategy is proposed for achieving dynamic chiral controls in self-assembly systems of plasmonic nanorods based on temperature-modulation.Via enlarging Au{100}side facets of Au nanorod(AuNR)building block and changing surface ligand from often-used cetyltrimethylammonium bromide(CTAB)to cetylpyridinium chloride(CPC),inversion of chiroptical signal in side-by-side(SS)oligomers is realized.Under the guide of chiral cysteine(Cys),Au{100}side facet-linked SS rods twist in the opposite direction compared with Au{110}side facet-linked counterparts.At high CPC concentration,by controlling the incubation temperature of chiral Cys,the dominant twist mode can be regulated.Finite-difference time-domain(FDTD)simulations indicate the key role of the twisting dihedral angle of the oligomers in driving chiral signal inversion.At low CPC concentration,a temperature-sensitive chiral switching is observed owing to the conformation change of the CPC ligand layer.The temperature-modulated chiral responses are based on the interactions of chiral molecules,achiral surface ligands,and exposed facets of the building block.The rich dynamic tunability of chiroptical responses of plasmonic assemblies may find applications in stimulus-responsive nanodevices.

关键词： plasmonic circular dichroism gold nanorods chiral oligomers cetylpyridinium chloride temperature stimulus