检索结果-南通市图书馆

Effect of Co on Solidification Characteristics and Microstructural Transformation of Non-equilibrium Solidified Cu-Ni Alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 444-453页

作者：安红恩 Bih-Lii Chua Ismail Saad Willey Yun Hsien Liew Materials engineering research group Faculty of EngineeringUniversity Malaysia Sabah88400 Kota KinabaluSabahMalaysia College of Mechanical and Electronic engineering Huanghe Jiaotong UniversityJiaozuo 454950China Henan engineering Technology research Center on Intelligent Manufacturing Technology and Equipment Jiaozuo 454950China Centre of research in Energy and Advanced Materials Faculty of EngineeringUniversiti Malaysia SabahJalan UMS88400 Kota KinabaluSabahMalaysia Nano engineering and Materials research group Faculty of EngineeringUniversity Malaysia Sabah88400 Kota KinabaluSabahMalaysia

Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating *** variation of the recalescence phenomenon with the degree of undercooling in the rapid solidification process was investigated using an infrared *** addition of the Co element affected the evolution of the recalescence phenomenon in Cu-Ni *** images of the solid-liquid interface migration during the rapid solidification of supercooled melts were captured by using a high-speed *** solidification rate of Cu-Ni alloys,with the addition of Co elements,was ***,the grain refinement structure with low supercooling was characterised using electron backscatter diffraction(EBSD).The effect of Co on the microstructural evolution during nonequilibrium solidification of Cu-Ni alloys under conditions of small supercooling is investigated by comparing the microstructures of Cu55Ni45 and Cu55Ni43Co2 *** experimental results show that the addition of a small amount of Co weakens the recalescence behaviour of the Cu55Ni45 alloy and significantly reduces the thermal strain in the rapid solidification *** the rapid solidification phase,the thermal strain is greatly reduced,and there is a significant increase in the characteristic undercooling ***,the addition of Co and the reduction of Cu not only result in a lower solidification rate of the alloy,but also contribute to the homogenisation of the grain size.

关键词： non-equilibrium solidification recalescence effect solidification character microstructure

A state-of-the-art review on delayed expansion of cemented paste backfill materials

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第8期43卷 3475-3500页

作者： Meng-Yuan Li Li-Jie Guo Yue Zhao Lei Zhang Kai Yang Xiao-Peng Peng Andrew Pan BGRIMM Technology group National Centre for International research On Green Metal Mining Department of Civil and Mineral engineering University of Toronto

Utilizing delayed expansion cemented paste backfill materials(DECPB) in mine backfill operations offers an effective solution to the challenge of achieving proper contact between the in-situ cemented backfill mass and the roof in mined-out areas(backfill-roof contact).This article presents recent progress in both theoretical and experimental research concerning *** types and mechanisms of expansive additives,including expansive agents,foaming agents,and expansive mineral materials relevant to DECPB,are explained,along with their impact on the expansive properties and mechanical characteristics of *** composition,material characteristics,preparation methods,and controlled release mechanisms of microcapsules are *** methods for measuring the volume change rate of paste backfill slurries are *** indicates that an appropriate content of expansive additives not only enhances the expansive properties of cemented paste backfill materials but also contributes to improving their mechanical *** foaming agents and bentonite are found to be more suitable for preparing DECPB compared to expansive *** delayed expansion of cemented paste backfill material is influenced by microcapsules,with their wall materials,preparation parameters,and the alkaline slurry environment affecting their controlled release *** and optimizing precise measurement devices and methods forfor the volume change rate of cemented paste backfill materials is essential requirement for studying the performance of *** delayed expansion technology with retarding techniques in cemented paste backfill materials can provide a reliable solution for achieving proper backfill-roof contact in the future.

关键词： Paste backfill Delayed expansion Mining with backfill Expansive additives Tailings

Experimental study on the dynamic response of a 3-D wedge under asymmetric impact

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第2期36卷 263-274页

作者： Saeed Hosseinzadeh Kristjan Tabri Maritime engineering research group School of EngineeringUniversity of SouthamptonSouthamptonUK Department of Civil engineering and Architecture Tallinn University of TechnologyTallinnEstonia Marine Technology Competence Center Tallinn University of TechnologyKuressaareEstonia

Water entry problems represent complex multiphase flows involving air,water,and structure interaction,occurring rapidly in rough seas,and potentially effecting structural integrity of floating *** paper experimentally investigates asymmetric slamming loads acting on a 3-D elastic wedge *** specimen,featuring two different bottom plates(stiffened and unstiffened),each 4 mm thick,aims to assess the effect of structural stiffness on dynamic *** experiments are conducted at different drop heights of 25 cm and 50 cm and varying heel angles from 5°to 25°.The paper describes the experimental conditions,including wedge geometry,material properties,and the test *** study explores the influence of heel angle on impact acceleration,revealing an increase in peak acceleration with a higher inclination angle,particularly in the vertical ***,the hydrodynamic pressure resulting from asymmetric slamming is *** pressure results analyzed and compared at different locations along the length of the *** experimental findings indicate that,despite the leeward side(stiffened)experiencing a smaller hydrodynamic load,the heel angle significantly affects pressure results on the windward side(unstiffened),leading to a more pronounced dynamic *** time history of pressure results emphasizes the effect of elastic vibrations,particularly noticeable on the unstiffened bottom *** study contributes to a deeper understanding of asymmetric slamming on aluminum structures,facilitating the enhancement of mathematical models and the validation of numerical simulations.

关键词： Flexible fluid structure interactions(FFSI) experimental study asymmetric impact hydrodynamic pressure slamming loads

A novel refined dynamic model of high-speed maglev train-bridge coupled system for random vibration and running safety assessment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2024年第7期31卷 2532-2544页

作者： MAO Jian-feng LI Dao-hang YU Zhi-wu CAI Wen-feng GUO Wei ZHANG Guang-wen School of Civil engineering Central South UniversityChangsha 410075China National engineering research Center of High-speed Railway Construction Technology Changsha 410075China China Railway group Limited Beijing 100039China China Railway Eryuan engineering group Co. Ltd.Chengdu 610031China

Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic *** motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element *** model is proven to be applicable by comparing with Monte Carlo *** applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability ***,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are *** results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.

关键词： maglev train-bridge interaction electromagnetic force-air gap model stochastic dynamic analysis running safety assessment probability density evolution method

Regression Method for Rail Fastener Tightness Based on Center-Line Projection Distance Feature and Neural Network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical engineering 2024年第2期37卷 356-371页

作者： Yuanhang Wang Duxin Liu Sheng Guo Yifan Wu Jing Liu Wei Li Hongjie Wang Robotics research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China China Construction Industrial&Energy engineering group Co. Ltd.Nanjing 210023China

In the railway system,fasteners have the functions of damping,maintaining the track distance,and adjusting the track ***,routine maintenance and inspection of fasteners are important to ensure the safe operation of track ***,assessment methods for fastener tightness include manual observation,acoustic wave detection,and image *** are limitations such as low accuracy and efficiency,easy interference and misjudgment,and a lack of accurate,stable,and fast detection *** at the small deformation characteristics and large elastic change of fasteners from full loosening to full tightening,this study proposes high-precision surface-structured light technology for fastener detection and fastener deformation feature extraction based on the center-line projection distance and a fastener tightness regression method based on neural ***,the method uses a 3D camera to obtain a fastener point cloud and then segments the elastic rod area based on the iterative closest point algorithm *** component analysis is used to calculate the normal vector of the segmented elastic rod surface and extract the point on the centerline of the elastic *** point is projected onto the upper surface of the bolt to calculate the projection ***,the mapping relationship between the projection distance sequence and fastener tightness is established,and the influence of each parameter on the fastener tightness prediction is ***,by setting up a fastener detection scene in the track experimental base,collecting data,and completing the algorithm verification,the results showed that the deviation between the fastener tightness regression value obtained after the algorithm processing and the actual measured value RMSE was 0.2196 mm,which significantly improved the effect compared with other tightness detection methods,and realized an effective fastener tightness regression.

关键词： Railway system Fasteners Tightness inspection Neural network regression 3D point cloud processing

Rapid monitoring of indoor airborne influenza and coronavirus with high air flowrate electrostatic sampling and PCR analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & engineering 2024年第7期18卷 73-85页

作者： Sanggwon An Sangsoo Choi Hyeong Rae Kim Jungho Hwang School of Mechanical engineering Yonsei UniversitySeoul 02876Republic of Korea Gas Metrology group Korea Research Institute of Standards and Science(KRISS)Daejeon 34113Republic of Korea

The World Health Organization has raised concerns about the possibility of airborne transmission in enclosed and poorly ventilated ***,rapid monitoring of airborne viruses is necessary in multi-use facilities with dense ***,an electrostatic air sampler(250 L/min)was developed in this work to obtain indoor viral aerosol samples for analysis via the Polymerase Chain Reaction(PCR).Aerosol tests with H1N1 and HCoV-229E were performed to evaluate the sample collection *** analysis,along with another aerosol test,was conducted to evaluate the recovery of the virus particles collected by the *** laboratory tests,our electrostatic sampler obtained viral samples that were detectable by PCR under the simulated viral pandemic scenario(3000 RNA copies per cubic meter of air)within 40 *** resulting cycle threshold(C)values were 35.07 and 37.1 for H1N1 and HCoV-229E,*** the performance evaluation in the laboratory,field tests were conducted in a university classroom from October 28 to December 2,*** A and HCoV-229E were detected in two air samples,and the corresponding C,values were 35.3 and *** PCR results are similar to those obtained from laboratory tests,considering the simulatedviralpandemic scenario.

关键词： Airborne virus Electrostatic sampler Rapid monitoring Indoor environment Field test

A High-Linear Radio Frequency Quadrature Modulator with Improved Sideband Suppression and Carrier Leakage Performance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第3期29卷 635-643页

作者： Yingdan Jiang Zongguang Yu Shutong Wu Li Li Xuelian Liu School of Electronic Science and engineering Nanjing UniversityNanjing 210093China The 58th research Institute of China Electronic Technology group Corporation Wuxi 214072China

The quadrature modulator is a crucial block in transmitters that upconverts baseband signals to theRadio Frequency(RF)band of interest using local oscillator *** this paper,non-ideal factors thatinfluence the performance of the quadrature modulator are considered,and solutions are accordingly taken inthe quadrature modulator design.A high-linear RF quadrature modulator with improved sideband suppressionand carrier leakage performance is presented in this *** quadrature modulator implemented in the0.18-μm SiGe process uses the current bleeding technique to improve the general performance of the doublebalanced active Gilbert *** on-chip prescaler followed by two cascaded limiting amplifiers is designed toprovide accurate quadrature local oscillator *** at quadrature baseband signal input ports areproposed to eliminate DC *** measured sideband suppression achieves a performance of better than−43 dBc and carrier leakage is less than−38 dBm over the output RF frequency range of 30 MHz to 2.15 *** output 1 dB compression point equals 11.4 dBm at 800 MHz.

关键词： Radio Frequency(RF) quadrature modulator sideband suppression carrier leakage linearity

Single-atom catalysts for the electrochemical reduction of carbon dioxide into hydrocarbons and oxygenates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2024年第3期6卷 64-117页

作者： Karl Adrian Gandionco Juwon Kim Lieven Bekaert Annick Hubin Jongwoo Lim Department of Chemistry Seoul National UniversitySeoulRepublic of Korea research group Electrochemical and Surface engineering(SURF) Department of Materials and ChemistryVrije Universiteit BrusselBrusselsBelgium

The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel *** this technology,an electrocatalytic material and renewable energy-generated electricity drive the conversion of carbon dioxide into high-value chemicals and carbon-neutral *** the past few years,single-atom catalysts have been intensively studied as they could provide near-unity atom utilization and unique catalytic ***-atom catalysts have become one of the state-of-the-art catalyst materials for the electrochemical reduction of carbon dioxide into carbon ***,it remains a challenge for single-atom catalysts to facilitate the efficient conversion of carbon dioxide into products beyond carbon *** this review,we summarize and present important findings and critical insights from studies on the electrochemical carbon dioxide reduction reaction into hydrocarbons and oxygenates using single-atom *** is hoped that this review gives a thorough recapitulation and analysis of the science behind the catalysis of carbon dioxide into more reduced products through singleatom catalysts so that it can be a guide for future research and development on catalysts with industry-ready performance for the electrochemical reduction of carbon dioxide into high-value chemicals and carbon-neutral fuels.

关键词： electrocatalysis electrochemical CO_(2)reduction hydrocarbons oxygenates single-atom catalysts

Pathway Planning of Nuclear Power Development Incorporating Assessment of Nuclear Event Risk

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 500-513页

作者： Xinxin Yang Yusheng Xue Bin Cai School of Electrical engineering Southeast UniversityNanjingChinaand they are also with State Grid Electric Power Research Institute(NARI Group Corporation)NanjingChina State Key Laboratory of Smart Grid Protection and Operation Control NanjingChina State Grid Electric Power research Institute(NARI group Corporation) NanjingChina

The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear power more *** paper aims to explore the impact of nuclear events on NPD pathway *** influence of nuclear events is quantified as a monetary risk component,and an optimization model that incorporates the NER in the objective function is *** optimize the pathway of NPD in the lowcarbon transition course of power supply structure evolution,a simulation model is built to deduce alternative NPD pathways and corresponding power supply evolution scenarios under the constraint of an exogenously assigned carbon emission pathway(CEP);moreover,a method is proposed to describe the CEP by superimposing the maximum carbon emission space and each carbon emission reduction(CER)component,and various CER components are clustered considering the emission reduction characteristics and resource endowments of different power generation technologies.A case study is conducted to explore the impact of NER and its risk valuation uncertainty on NPD pathway *** method presented in this paper allows the impact of nuclear events on NPD pathway planning to be quantified and improves the level of coordinated optimization of benefits and risks.

关键词： Low-carbon transition power supply structure evolution nuclear power development(NPD) quantitative analysis nuclear event risk evaluation