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Cool white light and tunable multicolor emission from Tb^(3+)/Dy^(3+)co-activated glasses under different excitations for WLEDs

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Journal of Rare Earths 2024年第1期42卷 46-56,I0002页

作者： L.Vijayalakshmi K.Naveen Kumar Jong Dae Baek department of Automotive engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea department of mechanical engineering Yeungnam UniversityGyeongsan38541Republic of Korea

A set of co-doped(Tb^(3+)/Dy^(3+))lithium zinc borate(LZB)glasses were developed by melt *** structural evaluation was performed for synthesized glassy *** Dy^(3+)and Tb^(3+)individually doped glasses exhibit intense yellow and green luminescence bands at 575 nm(^(4)F_(9/2)→^(6)H_(13/2))and543 nm(^(5)D_(4)→^(7)F_(5)),*** sensitization effect of Dy^(3+)on Tb^(3+)was analyzed by increasing the Tb^(3+)content with respect to the optimum Dy^(3+)content(0.5 mol%)in Dy^(3+)/Tb^(3+).The spectral overlay of Dy^(3+)luminescence and Tb^(3+)absorption profiles,Dy^(3+)/Tb^(3+)PL spectra under different excitations 352,362,376,and 385 nm,shortening decay lifetimes of Dy^(3+)in Dy^(3+)/Tb^(3+)co-activated glasses,energy transfer(ET)parameters,chromaticity coordinates and their corresponding correlated temperatures all help to explain ET from Dy^(3+)to Tb^(3+).At 385 nm of Dy^(3+)excitation,the optimized co-activated(0.5Dy^(3+)+1.0Tb^(3+)):LZB glass displays cool white light *** non-radiative ET from Dy^(3+)to Tb^(3+)is dominated by electric dipole-dipole interaction and its ET efficiency was calculated to be 63%.At the same time,reverse ET from Tb^(3+)to Dy^(3+)was also *** shift in color coordinates from dominant yellow to greenish-yellow,green and white light emission suggests that Dy^(3+)/Tb^(3+)coactivated LZB glasses can be a potential candidate for UV converted multicolor and white light emitting devices.

关键词： Rare earths Photoluminescence Energy transfer Spectral overlap Decay lifetime Multicolor emitting LEDs

Crack elimination and strength enhancement mechanisms of selective laser melted Si-modified Al−Mn−Mg−Er−Zr alloy

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Transactions of Nonferrous Metals Society of China 2024年第8期34卷 2431-2441页

作者： Jiang YU Yao-xiang GENG Hong-bo JU Zhi-jie ZHANG Jun-hua XU School of Materials Science and engineering Jiangsu University of Science and TechnologyZhenjiang 212100China department of mechanical engineering CEMMPRE-Centre for Mechanical Engineering Materials and ProcessesUniversity of CoimbraCoimbraPortugal

In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was *** effect of Si alloying on the surface quality,processability,microstructure,and mechanical properties of the SLM-fabricated alloy was *** results showed that introducing Si into the Al−Mn−Mg−Er−Zr alloy prevented balling and keyhole formation,refined the grain size,and reduced the solidification temperature,which eliminated cracks and increased the processability and process window of the *** maximum relative density of the SLM-fabricated Si/Al−Mn−Mg−Er−Zr alloy reached 99.6%.The yield strength and ultimate tensile strength of the alloy were(371±7)MPa and(518±6)MPa,*** values were higher than those of the SLM-fabricated Al−Mn−Mg−Er−Zr and other Sc-free Al−Mg-based alloys.

关键词： selective laser melting Al−Mn−Mg−Er−Zr−Si alloy surface roughness processability mechanical properties

Chaotic Aquila Optimization Algorithm for Solving Phase Equilibrium Problems and Parameter Estimation of Semi-empirical Models

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Journal of Bionic engineering 2024年第1期21卷 486-526页

作者： Oguz Emrah Turgut Mert Sinan Turgut Erhan Kırtepe department of Industrial engineering Faculty of Engineering and ArchitectureIzmir Bakircay UniversityMenemenizmirTurkey department of mechanical engineering Faculty of EngineeringEge UniversityBornovaizmirTurkey department of Motor Vehicles and Transportation Technologies Sirnak UniversitySirnakTurkey

This research study aims to enhance the optimization performance of a newly emerged Aquila Optimization algorithm by incorporating chaotic sequences rather than using uniformly generated Gaussian random *** work employs 25 different chaotic maps under the framework of Aquila *** considers the ten best chaotic variants for performance evaluation on multidimensional test functions composed of unimodal and multimodal problems,which have yet to be studied in past literature *** was found that Ikeda chaotic map enhanced Aquila Optimization algorithm yields the best predictions and becomes the leading method in most of the *** test the effectivity of this chaotic variant on real-world optimization problems,it is employed on two constrained engineering design problems,and its effectiveness has been ***,phase equilibrium and semi-empirical parameter estimation problems have been solved by the proposed method,and respective solutions have been compared with those obtained from state-of-art *** is observed that CH01 can successfully cope with the restrictive nonlinearities and nonconvexities of parameter estimation and phase equilibrium problems,showing the capabilities of yielding minimum prediction error values of no more than 0.05 compared to the remaining algorithms utilized in the performance benchmarking process.

关键词： Aquila optimization algorithm Chaotic maps Parameter estimation Phase equilibrium Unconstrained optimization

Machine learning enabling prediction in mechanical performance of Ti6Al4V fabricated by large-scale laser powder bed fusion via a stacking model

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Frontiers of mechanical engineering 2024年第4期19卷 29-43页

作者： Changjun HAN Fubao YAN Daolin YUAN Kai LI Yongqiang YANG Jiong ZHANG Di WANG School of mechanical and Automotive engineering South China University of TechnologyGuangzhou 510641China department of mechanical engineering College of EngineeringCity University of Hong KongHong Kong 999077China

Determining appropriate process parameters in large-scale laser powder bed fusion(LPBF)additive manufacturing pose formidable challenges that necessitate advanced approaches to minimize trial-and-error during *** work proposed a data-driven approach based on stacking ensemble learning to predict the mechanical properties of Ti6Al4V alloy fabricated by large-scale LPBF for the first *** method can adapt to the complexity of large-scale LPBF data distribution and exhibits a more generalized predictive capability compared to base ***,the stacking model utilized artificial neural network(ANN),gradient boosting regressor,kernel ridge regression,and elastic net as base models,with the Lasso model serving as the *** optimization and cross-validation were utilized for model optimization and training based on a limited data set,resulting in higher predictive accuracy compared to traditional artificial neural network *** statistical analysis of the ANN and stacking models indicates that the stacking model exhibits superior performance on the test set,with a coefficient of determination value of 0.944,mean absolute percentage error of 2.51%,and root mean squared error of 27.64,surpassing that of the ANN *** statistical metrics demonstrate superiority over those obtained from the ANN *** results confirm that by integrating the base models,the stacking model exhibits superior predictive stability compared to individual base models alone,thereby providing a reliable assessment approach for predicting the mechanical properties of metal parts fabricated by the LPBF process.

关键词： machine learning laser powder bed fusion ensemble learning stacking algorithm additive manufacturing

Deep neural network-enabled battery open-circuit voltage estimation based on partial charging data

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Journal of Energy Chemistry 2024年第3期90卷 120-132,I0005页

作者： Ziyou Zhou Yonggang Liu Chengming Zhang Weixiang Shen Rui Xiong State Key Laboratory of mechanical Transmission for Advanced Equipment&College of mechanical and Vehicle engineering Chongqing UniversityChongqing 400000China department of Vehicle engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China department of Electrical engineering Harbin Institute of TechnologyHarbin 150000HeilongjiangChina School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthornVictoria 3122Australia

Battery management systems(BMSs) play a vital role in ensuring efficient and reliable operations of lithium-ion *** main function of the BMSs is to estimate battery states and diagnose battery health using battery open-circuit voltage(OCV).However,acquiring the complete OCV data online can be a challenging endeavor due to the time-consuming measurement process or the need for specific operating conditions required by OCV estimation *** addressing these concerns,this study introduces a deep neural network-combined framework for accurate and robust OCV estimation,utilizing partial daily charging *** incorporate a generative deep learning model to extract aging-related features from data and generate high-fidelity OCV *** analysis is employed to identify the optimal partial charging data,optimizing the OCV estimation precision while preserving exceptional *** validation results,using data from nickel-cobalt-magnesium(NCM) batteries,illustrate the accurate estimation of the complete OCV-capacity curve,with an average root mean square errors(RMSE) of less than 3 *** this level of precision for OCV estimation requires only around 50 s collection of partial charging *** validations on diverse battery types operating under various conditions confirm the effectiveness of our proposed *** cases of precise health diagnosis based on OCV highlight the significance of conducting online OCV *** method provides a flexible approach to achieve complete OCV estimation and holds promise for generalization to other tasks in BMSs.

关键词： Lithium-ion battery Open-circuit voltage Health diagnosis Deep learning

Comparative analysis on the performance of different types of input-and command-shaping controllers in minimizing payload residual vibration of an overhead crane with an inclined supporting track

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International Journal of mechanical System Dynamics 2024年第1期4卷 22-33页

作者： Mohammed Alfares Khaled Alhazza mechanical engineering department College of Engineering and PetroleumKuwait UniversityKuwait CityKuwait

Reducing the effects of external disturbance on overhead crane systems is crucial,as they can impair the controller performance and cause excessive vibrations or oscillations of the *** such external disturbance is the inclination of the supporting track of the crane trolley,which causes the system dynamics model to *** open-loop control strategy is widely utilized to control the payload sway motion and generally does not require any alterations in the physical structure of a system or the installation of sensors and/or *** and command shaping are two common open-loop control techniques applied to control overhead *** this paper,the effect of moving an overhead crane system along an inclined supporting track is *** addition,the ability of different types of input-and command-shaping control schemes to suppress the residual vibrations due to trolley track inclination is *** types of input-shaping controllers,which are double-step,zero vibration,and one command waveform(WF)shaper based on a trigonometric function,are used and tested.A linear equation of motion of the overhead crane resting on an inclined surface is developed to simulate the overhead crane and payload *** effectiveness of the different types of open-loop controllers to suppress residual vibrations is verified by both simulation and experimental *** addition,a new WF command shaper is proposed and designed to overcome track inclination while eliminating payload residual vibration.A comprehensive comparative analysis,both numerically and experimentally,is performed on the new proposed shaper to measure its effectiveness in handling inclination when compared to other types of open-loop *** new shaper outperforms other controllers in eliminating payload residual vibration for a wider range of inclination angles.

关键词： overhead cranes open-loop control input and command shaping payload residual vibrations

Critical assessment of R410A alternatives for mini-split air conditioners in the Egyptian market

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Energy and Built Environment

Energy and Built Environment 2024年第3期5卷 426-445页

作者： Omar M.Zaki Omar Abdelaziz mechanical Power engineering department Faculty of EngineeringCairo UniversityGiza 12613Egypt department of mechanical engineering The American University in CairoAUC AvenueNew Cairo 11835Egypt

In this study,the potential implementation of three different low-GWP refrigerants(R32,R452B,and R454B)as replacements for R410A was *** study was performed using a simulation tool developed by the authors called RACHP-Lab,which is a vapor compression system simulation tool developed based on physics-based simulation for typical mini-split air *** simulation study was carried out and validated using experimental performance data of 10 different air conditioning units available in the Egyptian *** units included fixed-speed or variable-speed compressors and operated in cooling or heating ***-in replace-ment with the new refrigerants was carried *** R32,the capacity increased between 4.9%and 13%for cooling cases,and 6.3%and 12.4%for heating ***,COP did not improve in all *** R452B and R454B with direct replacement,the capacity nearly remained the same,with an increase of COP between 1.6%and 8.0%.Soft optimization was also conducted on cooling cases where compressor suction superheat,condenser subcooling,and compressor volumetric speed were optimized to maximize COP while maintaining the original capacity of R410A.R32 showed an improvement of COP over R410A between 4.6%and 15.5%,while for R452B and R454B between 2.2%and 13.2%.

关键词： Air conditioner Heat pump Alternative refrigerants Vapor compression cycle modeling

Machining dynamics and chatters in micro-milling:A critical review on the state-of-the-art and future perspectives

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Chinese Journal of Aeronautics 2024年第7期37卷 59-80页

作者： Qingshun BAI Peng WANG Kai CHENG Liang ZHAO Yabo ZHANG School of mechanical and Electrical engineering Harbin Institute of TechnologyHarbin 150001China department of mechanical and Aerospace engineering Brunel University LondonUxbridge UB83PHUK

Micro-milling technology is widely applied in micro manufacturing,particularly for the fabrication of miniature and micro ***,the chatters and machining dynamics related issues in micro-milling are often the main challenges restricting its machining quality and *** research works have rendered that the machining dynamics and chatters in micro-milling are more complex compared with the conventional macro-milling process,likely because of the size effect and rigidity of the micro-milling system including the tooling,workpiece,process variables,materials involved,and the high-speed milling machines,and further their collective dynamic ***,in this paper,the state of the art focusing on micro-milling chatters and dynamics related issues over the past years are comprehensively and critically reviewed to provide some insights for potential researchers and ***,typical applications and the problems caused by the machining dynamics and chatters in micro-milling have been put forward in this ***,the research on the underlying micro-cutting mechanics and dynamics,stability analysis,chatters detection,and chatter suppression are summarized ***,the underlying scientific and technological challenges are discussed particularly against typical precision engineering ***,the possible future directions and trends in research and development of micro-milling have been discussed.

关键词： Micro-milling Machining dynamics Micro-cutting mechanics Stability lobe diagram(SLD) Chatters suppression Digital twin

Broadband angular spectrum analog processors based on all-dielectric metasurfaces

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 188-190页

作者： Lin Deng Yongmin Liu department of Electrical and Computer engineering Northeastern UniversityBoston 02115USA department of mechanical and Industrial engineering Northeastern UniversityBoston 02115USA

Digital signal processors are extensively used to execute mathematical operations and advanced computational tasks on digital ***,they suffer from several inherent limitations,including low speed,high energy consumption,and large memory requirements,because of the hardware bottleneck and the imperative conversion between digital and analogue signals.

关键词： dielectric spectrum hardware