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Effect of geometry simplification and boundary condition specification on flow field and aerodynamic noise in the train head and bogie region of high-speed trains

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第9期25卷 716-731页

作者： Jiawei shi Yuan HE Jiye ZHANG tian LI State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China Institute of Sound and Vibration Research Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthampton SO171BJUK

The purpose of this study is to determine a suitable modeling method to make computational fluid dynamics(CFD)simulation more efficient for aeroacoustics optimization of the bogie region of high-speed *** this end,four modeling methods are considered,which involve different geometry simplifications and boundary condition *** corresponding models are named the three-car marshalling model,computational domain shortening model,carbody shortening model,and sub-domain *** the detached eddy simulation(DES)model and Ffowcs Williams-Hawkings(FW-H)equation,the unsteady flow field and far-field noise of the four models are *** evaluate the effect of the different modeling methods,the time-averaged flow field,fluctuating flow field,and far-field noise results of the four models are compared and analyzed in detail with the results of the three-car marshalling model used as basis for *** results show that the flow field results of the bogie region predicted by the four models have relatively high ***,the usage of the non-time varying outlet boundary conditions in the computational domain shortening model and sub-domain model could affect the pressure fluctuation on the upstream carbody *** only the bogie region is used as the source surface,the differences between the far-field noise results of the three simplified models and the three-car marshalling model are all within 1 dB;when the train head is used as the source surface,the results of the carbody shortening model and the three-car marshalling model are more consistent.

关键词： Bogie region Train head Flow field Aerodynamic noise Geometry simplification Boundary conditions

Systematic study of the synthesis of heavy and superheavy nuclei in 48Ca-induced fusion-evaporation reactions

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Nuclear Science and Techniques 2024年第7期35卷 157-172页

作者： shi-Hao Zhu tian-Liang Zhao Xiao-Jun Bao Department of Physics Collaborative Innovation Center for Quantum EffectsKey Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationHunan Normal UniversityChangsha410081China School of Nuclear Science and Technology Lanzhou UniversityLanzhou730000China School of Physics Xi’an Jiaotong UniversityXi’an710049China

We systematically studied the evaporation residue cross sections of ^(48)Ca-induced reactions on lanthanide and actinide target nuclei under the Dinuclear System(DNS)model framework to check the reliability and applicability of the *** produce new proton-rich Fl and Lv isotopes through hot fusion reactions in the superheavy element region with Z≥104,we utilized the reactions ^(48)Ca+^(2.6,2.8,2.9) Pu and ^(48)Ca+^(2.2.2.3,2.4,2.0) ***,owing to the detection limit of available equipment(0.1 pb),only 2.3Fl and 2.7−2.9Lv,which have the maximum evaporation residue cross section values of 0.149,0.130,9.52.,and 0.309 pb,respectively,can be ***,to produce neutron-deficient isotopes of actinides near the proton drip line with Z=93−100,we attempted to generate the new isotopes(2.4−2.7Pu,2.8−2.2.2.7Cm)using the reactions ^(48)Ca+180,182.183 W and ^(48)Ca+^(184,186,187,192. *** maximum evaporation residue cross section values are 0.07,0.06,0.2.,and 0.30 nb for the former set of reactions,and 1.96 pb,5.73 pb,12.16 pb,19.39 pb,54.79 pb,and 6.45 nb for the latter,*** results are expected to provide new information for the future synthesis of unknown neutron-deficient isotopes.

关键词： Dinuclear system(DNS)model Evaporation residue cross section Neutron-deficient isotopes

Oxygen vacancy boosting Fenton reaction in bone scaffold towards fighting bacterial infection

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International Journal of Extreme Manufacturing 2024年第1期6卷 296-311页

作者： Cijun Shuai Xiaoxin shi Feng Yang Haifeng tian Pei Feng State Key Laboratory of Precision Manufacturing for Extreme Service Performance College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083People’s Republic of China Institute of Additive Manufacturing Jiangxi University of Science and TechnologyNanchang 330013People’s Republic of China College of Mechanical Engineering Xinjiang UniversityUrumqi 830017People’s Republic of China

Bacterial infection is a major issue after artificial bone transplantation due to the absence of antibacterial function of bone scaffold,which seriously causes the transplant failure and even amputation in severe *** this study,oxygen vacancy(OV)defects Fe-doped Ti O2.OV-FeTiO2.nanoparticles were synthesized by nano TiO2.nd Fe3O4via high-energy ball milling,which was then incorporated into polycaprolactone/polyglycolic acid(PCLGA)biodegradable polymer matrix to construct composite bone scaffold with good antibacterial activities by selective laser *** results indicated that OV defects were introduced into the core/shell-structured OV-FeTiO2.anoparticles through multiple welding and breaking during the high-energy ball milling,which facilitated the adsorption of hydrogen peroxide(H2.2.in the bacterial infection microenvironment at the bone transplant *** accumulated H2.2.ould amplify the Fenton reaction efficiency to induce more hydroxyl radicals(·OH),thereby resulting in more bacterial deaths through·OH-mediated oxidative *** antibacterial strategy had more effective broad-spectrum antibacterial properties against Gram-negative Escherichia coli(***)and Gram-positive Staphylococcus aureus(***).In addition,the PCLGA/OV-FeTiO2.caffold possessed mechanical properties that match those of human cancellous bone and good biocompatibility including cell attachment,proliferation and osteogenic differentiation.

关键词： bacterial infection bone scaffold selective laser sintering Fenton reaction antibacterial properties

The relationship between interannual dry/wet changes and nomadic wars in the Hexi Corridor region of china during the period 2.1–1912.A.D.

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Science china Earth Sciences 2024年第6期67卷 1922-1931页

作者： Fei TANG Zhilin shi Qinhua tian Xiaogang DU Yong ZHANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Institute of Dunhuang Studies Lanzhou UniversityLanzhou 730020China National Climate Center China Meteorological AdministrationBeijing 100081China Longchanghe Station Gansu Qilian Mountain National Nature ReserveZhangye 734400China University of chinese Academy of Sciences Beijing 100049China

The link between climate and war has long been a topic of great scientific and social *** this study,we investigate the influence of climate on warfare in china’s Hexi Corridor region since 2.1 *** the superposed epoch analysis of tree-ring data and historical war data,we observe a notable correlation between interannual dry-wet variations and wars instigated by nomadic groups in the Hexi ***,this relation{2.p is dynamic and influenced by the region’s relative *** periods in which the Hexi Corridor was ruled by multiple regimes,wars tended to follow dry climatic conditions,which may be due to the fact that unusual drought during these periods likely heightened competition for resources and ***,during times of regional unity,wars were more likely to occur when climatic conditions were wet because the expansion of rangelands and the accumulation of resources helped fuel the nomads’outward *** findings underscore the complexity of the relation{2.p between war and climate *** gain a more comprehensive understanding of this relation{2.p,continuous,high-resolution historical temperature and humidity datasets with broader and more uniform coverage are needed across multiple *** addition,collecting and examining disaggregated historical war data for regions with distinct characteristics is essential.

关键词： Drought Interannual dry and wet variations War The Hexi Corridor Tree ring Nomadic groups

Counteracting effects on ENSO induced by ocean chlorophyll interannual variability and tropical instability wave-scale perturbations in the tropical Pacific

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Science china Earth Sciences 2024年第2期67卷 387-404页

作者： Rong-Hua ZHANG Feng tian Qidong shi Xiujun WANG Tongwen WU School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China Laoshan Laboratory Qingdao266237China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266071China University of chinese Academy of Sciences Beijing101408China Faculty of Geographical Sciences Beijing Normal UniversityBeijing100875China Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing100081China

Large perturbations in chlorophyll(chl)are observed to coexist at interannual and tropical instability wave(TIW)scales in the tropical Pacific;at present,their combined effects on El Ni?o-Southern Oscillation(ENSO)through ocean biologyinduced heating(OBH)feedbacks are not understood ***,a hybrid coupled model(HCM)for the atmosphere and ocean physics-biogeochemistry(AOPB)in the tropical Pacific is adopted to quantify how ENSO can be modulated by chl perturbations at interannual and TIW scales,individually or collectively,*** HCM-based sensitivity experiments demonstrate a counteracting effect on ENSO:the bio-climate feedback due to large-scale chl interannual variability acts to damp ENSO through its impact on upper-ocean stratification and vertical mixing,whereas that due to TIW-scale chl perturbations tends to amplify *** ENSO simulations are sensitively dependent on the ways chl effects are represented at these different scales,it is necessary to adequately take into account these related differential chl effects in climate modeling.A bias source for ENSO simulations is illustrated that is related with the chl effects in the tropical Pacific,adding in a new insight into interactions between the climate system and ocean ecosystem on different scales in the *** results reveal a level of complexity of ENSO modulations resulting from chl effects at interannual and TIW scales,which are associated with ocean biogeochemical processes and their interactions with physical processes in the tropical Pacific.

关键词： Ocean chlorophyll Bio-climate feedbacks Interannual variability Tropical instability waves Counteracting effects A hybrid coupled model

Intelligent laser-induced graphene sensor for multiplex probing catechol isomers

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chinese chemical Letters 2024年第7期35卷 227-234页

作者： tian Cao Xuyin Ding Qiwen Peng Min Zhang Guoyue shi School of chemistry and Molecular Engineering Shanghai Key Laboratory for Urban Ecological Processes and Eco-RestorationEast China Normal UniversityShanghai 200241China

Herein,we unveil the intelligent detection of multiple catechol isomers in complex environments utilizing both laser-induced graphene(LIG)and artificial neural network(ANN).The large scale-up manufacturing of LIG-based sensors(LIGS)with three-electrode configuration on polyimide(PI)is achieved by direct laser-writing and screen-printing *** LIGS shows excellent electrochemical performance toward catechol isomers,i.e.,hydroquinone(1,4-dihydroxybenzene,HQ),catechol(1,2.dihydroxybenzene,CT),and resorcinol(1,3-dihydroxybenzene,RC),with a low limit of detection(LOD)(CC,0.079μmol/L;HQ,0.093μmol/L;RC,1.18μmol/L).Moreover,the ANN model is developed for machine-intelligent to predict concentrations of catechol isomers under an interfering environment via a single *** six unique parameters extracted from the differential pulse voltammetry(DPV)response,the machine learning-based regression provides a coefficient of correlation with 0.998 and is able to correctly predict the total and individual concentrations in complex river ***,this work provides a guide for the preparation and application of LIGS via facile and cost-efficient mass production and the development of an intelligent sensing platform based on the ANN model.

关键词： Laser-induced graphene Phenolic pollutants Electrochemical detection Artificial neural network

Buckling Optimization of Curved Grid Stiffeners through the Level Set Based Density Method

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 711-733页

作者： Zhuo Huang Ye tian Yifan Zhang Tielin shi Qi Xia State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China

Stiffened structures have great potential for improvingmechanical performance,and the study of their stability is of great *** this paper,the optimization of the critical buckling load factor for curved grid stiffeners is solved by using the level set based density method,where the shape and cross section(including thickness and width)of the stiffeners can be optimized *** grid stiffeners are a combination ofmany single stiffenerswhich are projected by the corresponding level set *** thickness and width of each stiffener are designed to be independent variables in the projection applied to each level set ***,the path of each single stiffener is described by the zero iso-contour of the level set *** the single stiffeners are combined together by using the p-norm method to obtain the stiffener *** proposed method is validated by several numerical examples to optimize the critical buckling load factor.

关键词： Stiffener buckling optimization shape and cross section level set based density

Ferroelectric perovskite PbTiO_(3)for advanced photocatalysis

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Rare Metals 2024年第9期43卷 4038-4055页

作者： Shuang Zhao shi-shi Shen Lu Han Bo-{2.ao tian Na Li Wei {2.en Xi-Bao Li School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China School of Materials Science and Engineering Nanchang Hangkong UniversityNanchang 330063China Department of chemistry National University of SingaporeSingapore 117543Singapore

The ferroelectric semiconductor material PbTiO_(3)exhibits remarkable spontaneous polarization and photoelectric properties,positioning it as a promising polar *** internal electric field of ferroelectrics can separate photocarriers and enhance the catalytic performance of ***,when combined with other semiconductors,PbTiO_(3)contributes to the construction of a depolarization field,extending the catalytic applications of PbTiO_(3)***_(3)exhibits optical absorption,semiconductor,and piezoelectric *** piezoelectric polarization field enhances charge separation,modulates band structure,surface charge conduction,and heterojunction interface charge conduction,thereby amplifying photocatalytic *** paper begins by examining the structure,properties,and preparation methods of PbTiO_(3).Subsequently,it delves into the optimization of PbTiO_(3)'s structure and performance,exploring applications in photocatalysis as a ferroelectric *** is placed on the detailed discussion of surface modification,heterostructure formation,and ferroelectric polarization of PbTiO_(3)*** aspects are thoroughly explored for their role in regulating activity and optimizing the performance of photocatalysis and photopiezoelectric *** conclusion,the paper addresses the current research status of PbTiO_(3)ferroelectric materials and highlights the challenges that lie *** intention is to provide valuable references for the ongoing research in PbTiO_(3)ferroelectric materials.

关键词： PbTiO_(3) Ferroelectric polarization Photocatalysis Piezoelectric catalysis Polarization

White matter disease derived from vascular and demyelinating origins

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Stroke & Vascular Neurology 2024年第4期9卷 344-350页

作者： Lin-Jie Zhang De-Cai tian Li Yang Kaibin shi Yaou Liu Yilong Wang Fu-Dong shi Department of Neurology Tianjin Medical University General HospitalTianjinTianjinChina National Clinical Research Center for Neurological Diseases of china Beijing Tiantan HospitalCapital Medical UniversityBeijingBeijingChina

Damage or microstructural alterations of the white matter can cause dysfunction of the intrinsic neural networks in a condition termed as white matter disease(WMD).Frequently detected on brain computed tomography and magnetic resonance imaging scans,WMD is commonly presented in inflammatory demyelinating diseases like multiple sclerosis(MS)and vascular diseases such as cerebral small vessel disease(CSVD).Prevention of MS and CSVD progression requires early treatments with drastically different medications and approaches,as such,early and accurate diagnosis of WMD,derived from vascular or demyelinating etiologies,is of paramount ***,the clinical and imaging similarities between MS,especially during the early stage,and CSVD,pose a significant dilemma in differentiating these two *** this review,we attempt to summarize and contrast the distinguishing features of MS and CSVD for aiding accurate diagnosis to ensure timely corresponding management in the early stages of MS and CSVD.

关键词： diagnosis myelin alterations