Extremely large-scale hybrid reconfigurable intelligence surface(XL-HRIS),an improved version of the RIS,can receive the incident signal and enhance communication performance.However,as the RIS size increases,the phas...Extremely large-scale hybrid reconfigurable intelligence surface(XL-HRIS),an improved version of the RIS,can receive the incident signal and enhance communication performance.However,as the RIS size increases,the phase variations of the received signal across the whole array are nonnegligible in the near-field region,and the channel model mismatch,which will decrease the estimation accuracy,must be considered.In this paper,the lower bound(LB)of the estimated parameter is studied and the impacts of the distance and signal-tonoise ratio(SNR)on LB are then evaluated.Moreover,the impacts of the array scale on LB and spectral efficiency(SE)are also studied.Simulation results verify that even in extremely large-scale array systems with infinite SNR,channel model mismatch can still limit estimation accuracy.However,this impact decreases with increasing distance.展开更多
Model is usually necessary for the design of a control loop. Due to simplification and unknown dynamics, model plant mismatch is inevitable in the control loop. In process monitoring, detection of mismatch and evaluat...Model is usually necessary for the design of a control loop. Due to simplification and unknown dynamics, model plant mismatch is inevitable in the control loop. In process monitoring, detection of mismatch and evaluation of its influences are demanded. In this paper several mismatch measures are presented based on different model descriptions. They are categorized into different groups from different perspectives and their potential in detection and diagnosis is evaluated. Two case studies on mixing process and distillation process demonstrate the efficacy of the framework of mismatch monitoring.展开更多
氧化物冶金技术在促进材料微观结构细化方面具有显著效果,这一强化机制与非金属夹杂物和基体之间的界面特性密切相关。基于二维错配度理论和界面形核理论,建立了一套系统评估非金属夹杂物在氧化物冶金中效用性的理论模型,并以典型TiN夹...氧化物冶金技术在促进材料微观结构细化方面具有显著效果,这一强化机制与非金属夹杂物和基体之间的界面特性密切相关。基于二维错配度理论和界面形核理论,建立了一套系统评估非金属夹杂物在氧化物冶金中效用性的理论模型,并以典型TiN夹杂物为例进行了计算验证。首先,通过二维错配度理论计算了TiN与铁素体(body centred cube-Fe,BCC-Fe)和奥氏体(face center cubic-Fe,FCC-Fe)的晶格匹配关系,结果显示TiN(100)/BCC-Fe(100)界面和TiN(110)/BCC-Fe(110)界面的错配度均为4.61%,表明TiN可作为铁素体形核的潜在基底;而TiN与奥氏体的错配度较大,难以形成稳定的界面结构。随后,基于表面收敛测试,选择5层BCC-Fe、7层FCC-Fe和9层TiN表面结构建立了TiN/BCC-Fe和TiN/FCC-Fe的界面模型。基于第一性原理计算的界面能量结果表明,TiN/FCC-Fe界面的黏附功呈负值,证实了TiN不能作为奥氏体的形核核心,反而可以阻碍奥氏体晶粒长大,发挥钉扎晶粒的作用;而TiN/BCC-Fe界面具有正黏附功值,表明TiN可以有效诱导铁素体形核。值得注意的是,TiN/BCC-Fe的界面能明显低于TiN/FCC-Fe的界面能,这一热力学优势为奥氏体内铁素体的形核提供了理论依据。在TiN/BCC-Fe体系中,TiN(100)/BCC-Fe(100)-N界面具有较大的黏附功和最小的界面能,表现出最强的稳定性。电子结构分析表明在TiN(100)/BCC-Fe(100)-N,TiN(110)/BCC-Fe(110)-Ti和TiN(110)/BCC-Fe(110)-N界面处均形成了Fe—N离子键,支撑了界面的稳定形成。研究结果为理解氧化物冶金中夹杂物诱导相变机制提供了新的理论视角。展开更多
The conventional analytical method of predicting strain in a thin film under bending is restricted to the uniform material assumption, while in flexible electronics, the film/substrate structure is widely used with mi...The conventional analytical method of predicting strain in a thin film under bending is restricted to the uniform material assumption, while in flexible electronics, the film/substrate structure is widely used with mismatched material properties taken into account. In this paper,a piecewise model is proposed to analyze the axial strain in a thin film of flexible electronics with the shear modification factor and principle of virtual work. The excellent agreement between analytical prediction and finite element results indicates that the model is capable of predicting the strain of the film/substrate structure in flexible electronics, whose mechanical stability and electrical performance is dependent on the strain state in the thin film.展开更多
基金supported in part by the National Natural Science Founda⁃tion of China(NSFC)under Grant Nos.62301148,62341107,and 62261160576by the Natural Science Foundation of Jiangsu Prov⁃ince under Grant No.BK20230824in part by the Key Technologies R&D Program of Jiangsu(Prospective and Key Technologies for Indus⁃try)under Grant Nos.BE2023022 and BE2023022-1.
文摘Extremely large-scale hybrid reconfigurable intelligence surface(XL-HRIS),an improved version of the RIS,can receive the incident signal and enhance communication performance.However,as the RIS size increases,the phase variations of the received signal across the whole array are nonnegligible in the near-field region,and the channel model mismatch,which will decrease the estimation accuracy,must be considered.In this paper,the lower bound(LB)of the estimated parameter is studied and the impacts of the distance and signal-tonoise ratio(SNR)on LB are then evaluated.Moreover,the impacts of the array scale on LB and spectral efficiency(SE)are also studied.Simulation results verify that even in extremely large-scale array systems with infinite SNR,channel model mismatch can still limit estimation accuracy.However,this impact decreases with increasing distance.
基金Supported in part by the National Basic Research Program of China (2012CB720500)the Erasmus Mundus Europe Asia(EMEA) Scholarship Program
文摘Model is usually necessary for the design of a control loop. Due to simplification and unknown dynamics, model plant mismatch is inevitable in the control loop. In process monitoring, detection of mismatch and evaluation of its influences are demanded. In this paper several mismatch measures are presented based on different model descriptions. They are categorized into different groups from different perspectives and their potential in detection and diagnosis is evaluated. Two case studies on mixing process and distillation process demonstrate the efficacy of the framework of mismatch monitoring.
文摘氧化物冶金技术在促进材料微观结构细化方面具有显著效果,这一强化机制与非金属夹杂物和基体之间的界面特性密切相关。基于二维错配度理论和界面形核理论,建立了一套系统评估非金属夹杂物在氧化物冶金中效用性的理论模型,并以典型TiN夹杂物为例进行了计算验证。首先,通过二维错配度理论计算了TiN与铁素体(body centred cube-Fe,BCC-Fe)和奥氏体(face center cubic-Fe,FCC-Fe)的晶格匹配关系,结果显示TiN(100)/BCC-Fe(100)界面和TiN(110)/BCC-Fe(110)界面的错配度均为4.61%,表明TiN可作为铁素体形核的潜在基底;而TiN与奥氏体的错配度较大,难以形成稳定的界面结构。随后,基于表面收敛测试,选择5层BCC-Fe、7层FCC-Fe和9层TiN表面结构建立了TiN/BCC-Fe和TiN/FCC-Fe的界面模型。基于第一性原理计算的界面能量结果表明,TiN/FCC-Fe界面的黏附功呈负值,证实了TiN不能作为奥氏体的形核核心,反而可以阻碍奥氏体晶粒长大,发挥钉扎晶粒的作用;而TiN/BCC-Fe界面具有正黏附功值,表明TiN可以有效诱导铁素体形核。值得注意的是,TiN/BCC-Fe的界面能明显低于TiN/FCC-Fe的界面能,这一热力学优势为奥氏体内铁素体的形核提供了理论依据。在TiN/BCC-Fe体系中,TiN(100)/BCC-Fe(100)-N界面具有较大的黏附功和最小的界面能,表现出最强的稳定性。电子结构分析表明在TiN(100)/BCC-Fe(100)-N,TiN(110)/BCC-Fe(110)-Ti和TiN(110)/BCC-Fe(110)-N界面处均形成了Fe—N离子键,支撑了界面的稳定形成。研究结果为理解氧化物冶金中夹杂物诱导相变机制提供了新的理论视角。
基金support from the National Natural Science Foundation of China(No.11172022)the support by the China Postdoctoral Science Foundation(No.2013M530907)the National Natural Science Foundation of China(No.11302039)
文摘The conventional analytical method of predicting strain in a thin film under bending is restricted to the uniform material assumption, while in flexible electronics, the film/substrate structure is widely used with mismatched material properties taken into account. In this paper,a piecewise model is proposed to analyze the axial strain in a thin film of flexible electronics with the shear modification factor and principle of virtual work. The excellent agreement between analytical prediction and finite element results indicates that the model is capable of predicting the strain of the film/substrate structure in flexible electronics, whose mechanical stability and electrical performance is dependent on the strain state in the thin film.
