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Thermodynamics aided design of hBN-capsulated diboride powders from novel nitrate precursors for high entropy ceramics

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Journal of Materials Science & technology 2024年第11期178卷 133-142页

作者： Hailing Yang Ji Zou Zhimin Xiong Jingjing Liu Weimin Wang Zhengyi Fu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000China

Hexagonal BN-coated powders have been widely used in various engineering sectors,however,their pro-ductions are restricted by the complexity of gas-solid *** this study,guided by thermodynamics,a novel approach to synthesize Layer-structured hexagonal BN(hBN)-coated high entropy diboride pow-ders in vacuum was developed,using metal salt Zr(NO_(3))4·5H_(2)O,HfCl_(4),NbC_(15),TaC_(15),C_(16)H_(36)O_(4)Ti,boric acid,and sucrose as raw *** adjusting the ratio of carbon to metal source(C/M),powders only consisting of two boride solid solutions and hBN were finally obtained,under an optimal process-ing condition of C/M=5.5 and synthesis temperature of 1400 ℃.Parts of hBN were found to coat on high-entropy metal diborides ceramic(HEB)particles,corresponding formation mechanism for core-shell structured powders was investigated,together with the liquid precursor assisted boro/carbothermal re-duction *** from as-synthesized core-shell powders,(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B2-11 vol%hBN ceramics were densified at 1900 ℃ under 50 MPa without holding,with a high relative density of 97.3%.

关键词： High entropy boride Boro/carbothermal reduction Sol-gel Core-shell powders Densification

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A Longitudinal and Lateral Coordinated Control Method of Autonomous Vehicles Considering Time-varying Delay

IEEE Transactions on Intelligent Vehicles

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IEEE Transactions on Intelligent Vehicles 2024年 1-15页

作者： Qin, Zhaobo Liang, Wang Zang, Zuoxu Chen, Liang Hu, Manjiang Cui, Qingjia Bian, Yougang State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha China

In order to improve the control accuracy and stability of autonomous vehicles under large delay conditions, the paper proposes a longitudinal and lateral coordinated control method considering fixed sensor delay, actuator lag, and timevarying CAN communication delay. An adaptive all-pass filter time-delay estimator (AAPF-TDE) based on finite impulse response (FIR) and its improved strategies are designed to realize accurate online estimation of CAN communication delay. According to the estimated delay, a longitudinal and lateral coupling time-delay dynamics model with prediction revision and delay augmentation is constructed. A model predictive controller (MPC) combined with Lyapunov asymptotic stability constraints is then designed. CarSim/Simulink co-simulation and vehicle experiment results show that the proposed controller can improve the vehicle stability effectively while ensuring the longitudinal and lateral control accuracy under large delay conditions compared with the controller without considering delay or only considering fixed delay. IEEE

关键词： Time delay

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Promising thermal photonic management materials for sustainable human habitat

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Nano Research 2024年第1期17卷 112-131页

作者： Houze Yao Qihua Liao Huhu Cheng Liangti Qu Key Laboratory of Organic Optoelectronics&Molecular Engineering Ministry of EducationDepartment of ChemistryLaboratory of Flexible Electronics TechnologyTsinghua UniversityBeijing 100084China State Key Laboratory of Tribology in Advanced Equipment(SKLT) Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The spectral characteristics of outdoor structures,such as automobiles,buildings,and clothing,determine their energy interaction with the environment,from broad-spectrum absorption of light energy to high-efficiency thermal *** developed spectrally selective absorption(SSA)materials permit the reduction of energy loss from human habitat eco-system in the sustainable way and further reduce the utilization of fossil energy to achieve carbon *** we review recent advances in SSA materials that enable rational and efficient management of thermal energy and provide new solutions for the resource base that supports human life like comfortable heat management,electricity production,and water *** basic principles of thermal photonic management,the regulation of SSA materials,and functional properties are *** outlook discussing challenges and opportunities in SSA material energy management for comfortable living environments is finally presented,which expects the enormous potential of this interdisciplinary research in solving growing resource-shortage of human society.

关键词： spectrally selective absorption passive cooling solar power eco-system

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Thermal cycling on microstructure and mechanical properties of laser powder bed fusion manufactured IN738LC alloy

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Rare Metals 2024年第12期43卷 6649-6672页

作者： Yong Hu Hui-Bin Jia Yong-Qi Hu Cheng Chu Xu Zhang Li-Hua Wang Dong Zhang School of Material Science and Engineering Lanzhou University of TechnologyLanzhou730050China State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of TechnologyLanzhou730050China State Key Laboratory of Nickel and Cobalt Resources Comprehensive Utilization Jinchang737100China

This study investigated the impact of thermal cycling effects on the microstructure and mechanical properties of IN738LC alloy manufactured by laser powder bed fusion,considering different volumetric energy densities(VEDs)and interlayer times(ILTs)as part of the experimental *** results show that low VED and long ILT samples displayed superior quality,with an average grain size of 10.97μm and relatively low strain accumulation *** contrast,samples with high VED and long ILT exhibit increased cracking and porosity,the average grain size is 14.63μm and present higher strain accumulation *** nano-primary MC phase within the alloy transformed into a spherical secondary MC phase inside the grain and a polygonal secondary MC phase on the grain *** the low VED and long ILT,the mean equivalent diameter(MED)of MC carbide within the grain and on the grain boundary was 63 and 140 nm,respectively,the tensile strength was 1072±21 *** contrast,for the high VED and long ILT,the MED of MC carbide in the grain and on the grain boundary were 47 and105 nm,respectively,and the tensile strength was794±31 *** tensile strength of high VED and long ILT decreased by 26%compared with low VED and long ILT.

关键词： Laser powder bed fusion(L-PBF) IN738LC alloy Thermal cycling Microstructure Mechanical properties

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Analysis of an Axial-flux Slotted Limited-angle Torque Motor with Quasi-Halbach Array for Torque Performance Improvement

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CES Transactions on Electrical Machines and Systems 2023年第3期7卷 266-274页

作者： Mingjie Wang Dawei Li Ronghai Qu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China IEEE

Better torque performance and higher reliability have long been the focus of research for slotted limited-angle torque motors(LATMs),which are primarily used to position first-stage valves in electrohydraulic *** paper presents a high reliability axial-flux slotted LATM with quasi-Halbach array for torque performance improvement including constant torque range(CTR)and output ***,the structure with two sets of windings and the operation principle of the proposed slotted LATM is ***,a brief design procedure is presented,the structure selections of open slot and double-stator single-rotor(DSSR)interior rotor with surface mounted quasi-Halbach permanent magnet(PM)array are illustrated,and the geometric parameters are optimized to obtain the optimal design of the proposed slotted ***,3-D finite-element method(FEM)is employed to compare the proposed slotted LATM with the conventional surface mounted PM slotted LATM in terms of cogging torque,no-load back EMF,and output torque,and the results show that the proposed LATM with quasi-Halbach array has a 10%improvement in output torque and a 25%improvement in ***,the flux linkages and torque performance of the two sets of windings under various conditions verify good magnetic ***,prototypes of two different rotor types are manufactured and a series of experiments are performed to validate the analysis.

关键词： Limited-angle torque motor(LATM) Axial-flux machine Quasi-Halbach array Finite-element method(FEM) Cogging torque Torque performance

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Study of Star-Delta Soft Switch to Extend AC Motor High Speed Operation Region

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CES Transactions on Electrical Machines and Systems 2023年第3期7卷 248-255页

作者： Yixuan Shuai Dong Jiang Zhuo Chen Zicheng Liu Haijing Sun Peng Li IEEE State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

In traction application,speed range of motor is an important index for motor *** AC motor control,the maximum speed of the motor is limited by the output voltage capability of the traditional three-phase inverter with star connenction of *** the star connection to delta connection in high-speed range can extend the speed *** order to extend the speed operation region,star-delta switch proposed by many literatures relies on mechanical relay,which needs a dead zone of tens of milliseconds and seriously affects torque ***,the traditional method will cause current overshoot during the switch transient process,decreasing the device security and *** at the defects existing in the star-delta hard switching,this paper proposes a star-delta soft switching *** adding extra power electronics devices,DC-bus capacitor is used to provide the path of zero axis current in the transient process,which helps to achieve the smooth torque output and zero current switch in the *** have been done to validate the performance of the proposed *** switching transient from star to delta connection in the motor drive can be much more stable than hard switching method.

关键词： Speed range Soft switch 0-axis current Zero current switch

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Torque Ripple Suppression Method for Segmental Rotor Switch Reluctance Motor Based on Current Profile Optimization 26

Torque Ripple Suppression Method for Segmental Rotor Switch ...

引用

26th International Conference on Electrical Machines and Systems, ICEMS 2023

作者： Yang, Yang Sun, Jianbo Gan, Chun Wang, Shuanghong Zhao, Ziqi Yu, Zhiyue Qu, Ronghai Wu, Huangyuan Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnets Engineering and Technology Wuhan China Cyan Exploring Power Technology Wuxi Co Wuxi China

ISBN: (纸本)9798350317589

This paper proposes a novel torque ripple suppression method based on current profile optimization for segmental-rotor switch reluctance motor (SSRM). Instead of directly optimizing the phase current at each position, with the Fourier series expression, the phase current profile is expressed by a set of Fourier coefficients, turn-on angle, and conduction angle. With a certain phase current root mean square value, these three kinds of parameters above are optimized for torque ripple reduction on the premise of maintaining the output torque capability. With the optimized current profile, the torque ripple can be effectively suppressed. Besides, with the limitation of the conducting interval, the current in the low torque production region can be controlled to zero, which reduces the torque ripple and the copper loss. Finite element simulation results show that the proposed method has a good torque ripple suppression effect in both light load and rated conditions. © 2023 IEEE.

关键词： Fourier series

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A bi-functional catalyst strategy to selectively regulate sulfur redox kinetics in lithium-sulfur batteries

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Journal of Materials Science & technology 2024年第6期173卷 54-62页

作者： Yanan Liu Xiaoxiao Huang Honglei Zhang Guangyu Qin Xiaoshuang Wang Meixiu Song Hongbo Liang Jingzhe Hong Yudong Huang State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China MIIT Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001China

Designing electrochemical catalysts has become a research hotspot due to their accelerating the polysulfide conversion of the sulfur cathode to inhibit the“shuttle effect”in lithium-sulfur ***,it is still a great challenge to design the heterogeneous selective electrochemical catalyst for inhibiting the“shuttle effect”.Herein,nickel cobalt phosphide and cobalt phosphide as the heterogeneous catalyst active sites embedded in the nitrogen-doped hollow carbon nanocages(NiCoP@CoP/NC)are reported,used for multi-step and multi-phase sulfur electrode reaction,and it is found that metal-sulfur d-p hybridization can effectively indicate the intrinsic catalytic activity of metal *** of labor and cooperation of the bi-active NiCoP@CoP as heterogeneous catalysts propel the stepwise polysulfide *** and CoP sites preferentially accelerate the long-chain polysulfide conversion reaction(S_(8)■LiPSs)and the short-chain polysulfide conversion reactions(LiPSs■Li_(2)S),***,the hollow and porous N-doped carbon structure can successfully suppress the volume effect and improve the conductivity of the sulfur *** unique design can obtain an effective inhibition of the shuttle effect and rapid electrode *** a result,Li-S batteries demonstrate a high initial capacity of 1063 mAh g^(-1) and a low-capacity decay of 0.04% per cycle within 1000 *** work provides a feasible idea for the design of host materials in Li-S batteries.

关键词： Shuttle effect d-p hybridization Heterogeneous catalysts Stepwise polysulfide conversion

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Micro-strain regulation strategy to stabilize perovskite lattice based on the categories and impact of strain on perovskite solar cells

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Journal of Energy Chemistry 2025年第1期100卷 578-604页

作者： Caixia Li Wenwu Liu Shiji Da Lingbin Kong Fen Ran State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050GansuChina School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050GansuChina

Photovoltaic metal halide perovskite solar cells(PSCs) convert light to electricity more efficiently than crystalline silicon cells, and the cost of materials used to make them is lower than that of silicon *** efficiency is not a core issue affecting the application of perovskite solar cells in special *** present, stability is the major technical encounters that hinders its further commercial development. Microstrain in PSCs is currently a significant factor responsible for the device's instability. Strain-induced ion migration is widely believed to accelerate perovskite degradation even when external stimuli are ***, it is imperative to study strain to enhance the stability of PSCs. This paper reviews recent developments to understand strain's origin and effect mechanisms on performance of PSCs, including ion migration,failure behavior, defect formation, and its effect on photoelectric properties, stability, and ***, several well-known strain management strategies are systematically introduced based on the strain effect mechanism and strain engineering on the film, providing more clues for further preparation with increased stability. The manipulation of external physical strain applied from films to entire devices has been extensively studied. Furthermore, recommendations for future research directions and chemical approaches have been provided. It is emphasized that strain engineering plays a crucial role in improving the efficiency and longevity of PSCs. Tensile strain causes rapid degradation, while moderate compressive strain and external strain control could improve properties and stability. Efforts should focus on controlling compressive strain to mitigate residual tensile strain and introducing it in a controlled manner. Future research endeavors may focus on exploring these pathways to improve the efficiency and lifespan of PSCs.

关键词： Halide perovskite solar cells Strain origins Strain effects Strain management

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Enhanced rate capability and cycle stability of Ti2C MXene for sodium storage through an aniline molecules welding strategy

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Tungsten 2025年第1期7卷 161-171页

作者： Hao Chen Ya-Qin Wang Dong-Ting Zhang Bei Zhao Min-Peng Li Chen-Yang Li Tian-Peng Xu Mao-Cheng Liu State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of Technology School of Materials Science and Engineering Lanzhou University of Technology School of Computer and Communication Technology Lanzhou University of Technology

MXenes obtained significant attention in the field of energy storage devices due to their characteristic layered structure,modifiable surface functional groups,large electrochemically active surface,and regulable interlayer ***,the self-restacking and sluggish ions diffusion kinetics performance of MXenes during the alkali metal ions insertion/extraction process severely impedes their cycle stability and rate *** paper proposes an aniline molecule welding strategy for welding p-phenylenediamine（PPDA） into the interlayers of Ti2C through a dehydration condensation *** welded PPDA molecules can contribute pillar effect to the layered structure of *** pillar effect effectively maintains the structural stability during the sodium ions insertion/extraction process and effectively expands the interlayer spacing of Ti2C from 1.16 to 1.38 nm,thereby enhancing ions diffusion kinetics performance and improving the long-term cycle *** Ti2C-PPDA demonstrates outstanding Na+storage capability,exhibiting a specific capacity of 100.2 mAh·g-1at a current density of 0.1 A·g-1over 960 cycles and delivering a remarkable rate capability 81.2 mAh·g-1at a current density of 5 A·*** study demonstrates that expanding interlayer spacing is a promising strategy to enhance the Na+storage capacity and improve long-term cycling stability,which provides significant guidance for the design of two-dimensional Na+storage materials with high-rate capability and cycle stability.

关键词： Ti_2C Expanding interlayer spacing Sodium ions storage Diffusion kinetics Rate capability

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