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Field trial measurement and channel modeling for reconfigurable intelligent surface 被引量:2
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作者 Peng Zheng jianwen ding +5 位作者 Dan Fei Jiayi Zhang Bo Ai Xiao Li Shi Jin Tiejun Cui 《Digital Communications and Networks》 SCIE CSCD 2023年第3期603-612,共10页
With the advantage of programmable electromagnetic properties,Reconfigurable Intelligent Surfaces(RISs)havedrawn wide attention from both industry and academia.RIS-assisted communication systems can promote hugewirele... With the advantage of programmable electromagnetic properties,Reconfigurable Intelligent Surfaces(RISs)havedrawn wide attention from both industry and academia.RIS-assisted communication systems can promote hugewireless channel quality improvement and remarkable coverage enhancement.This paper proposes generalpathloss model,radiation pattern and mirror beam effect of 1-bit RIS at sub-6 GHz band.Field trails have beencarried out in outdoor and indoor deployment scenarios.The proposed model is validated through extensivesimulations and field-trial measurements.In addition,an optimized RIS phase-shit design process for the mirrorbeam elimination is proposed and validated with simulations.The proposed theoretical model and measurementresults can promote future research and application in RIS-assisted communications. 展开更多
关键词 Reconfigurable intelligent surfaces Channel measurement Path loss PROTOTYPE
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Radio Communication Scenarios in 5G-Railways 被引量:1
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作者 Ruisi He Bo Ai +8 位作者 Zhangdui Zhong Mi Yang Chen Huang Ruifeng Chen jianwen ding Hang Mi Zhangfeng Ma Guiqi Sun Changzhu Liu 《China Communications》 SCIE CSCD 2023年第9期235-246,共12页
With the rapid development of railways,especially high-speed railways,there is an increasingly urgent demand for new wireless communication system for railways.Taking the mature 5G technology as an opportunity,5G-rail... With the rapid development of railways,especially high-speed railways,there is an increasingly urgent demand for new wireless communication system for railways.Taking the mature 5G technology as an opportunity,5G-railways(5G-R)have been widely regarded as a solution to meet the diversified demands of railway wireless communications.For the design,deployment and improvement of 5GR networks,radio communication scenario classification plays an important role,affecting channel modeling and system performance evaluation.In this paper,a standardized radio communication scenario classification,including 18 scenarios,is proposed for 5GR.This paper analyzes the differences of 5G-R scenarios compared with the traditional cellular networks and GSM-railways,according to 5G-R requirements and the unique physical environment and propagation characteristics.The proposed standardized scenario classification helps deepen the research of 5G-R and promote the development and application of the existing advanced technologies in railways. 展开更多
关键词 5G-R scenario classification smart rail-ways
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Formation and evolution of layered structure in dissimilar welded joints between ferritic-martensitic steel and 316L stainless steel with fillers 被引量:4
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作者 Guoliang Liu Shanwu Yang +7 位作者 jianwen ding Wentuo Han Lujun Zhou Mengqi Zhang Shanshan Zhou RDKMisra Farong Wan Chengjia Shang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2019年第11期2665-2681,共17页
Dissimilar high-energy beam(HEB)welding is necessary in many industrial applications.Different composition of heat-affected zone(HAZ)and weld metal(WM)lead to variation in mechanical properties within the dissimilar j... Dissimilar high-energy beam(HEB)welding is necessary in many industrial applications.Different composition of heat-affected zone(HAZ)and weld metal(WM)lead to variation in mechanical properties within the dissimilar joint,which determines the performance of the welded structure.In the present study,appropriate filler material was used during electron beam welding(EBW)to obtain a reliable dissimilar joint between reduced-activation ferritic-martensitic(RAFM)steel and 316L austenitic stainless steel.It was observed that the layered structure occurred in the weld metal with 310S filler(310S-WM),which had the inferior resistance to thermal disturbance,leading to severe hardening of 310S-WM after one-step tempering treatment.To further ameliorate the joint inhomogeneity,two-step heat treatment processes were imposed to the joints and optimized.δ-ferrite in the layered structure transformed intoγ-phase in the first-step normalizing and remained stable during cooling.In the second-step of tempering,tempered martensite was obtained in the HAZ of the RAFM steel,while the microstructure of 310S-WM was not affected.Thus,the optimized properties for HAZ and 310S-WM in dissimilar welded joint was both obtained by a two-step heat treatment.The creep failure position of two dissimilar joints both occurred in CLAM-BM. 展开更多
关键词 Dissimilar welding with fillers Electron beam welding Layered structure Post weld heat treatment Microstructural evolution
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Characterization of Compactness of Rust Layers on Weathering Steels by an Adsorption/Dehydration Test of Ethanol 被引量:1
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作者 Lujun Zhou Shanwu Yang +5 位作者 Yi Dong Wenhua Zhang jianwen ding Guoliang Liu Chengjia Shang Raja Devesh Kumar Misra 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2020年第6期846-856,共11页
A new method for evaluating the compactness of rust layers on steels has been proposed in the present study. The method includes adsorption and dehydration process of anhydrous ethanol. The protective ability of rust ... A new method for evaluating the compactness of rust layers on steels has been proposed in the present study. The method includes adsorption and dehydration process of anhydrous ethanol. The protective ability of rust layers can be qualitatively reflected by the adsorption/dehydration rates. The specific surface area and porosity of rust layers can be calculated by a quantitative model. The results from the present method are consistent with electrochemical tests, N2 adsorption and X-ray diffraction analysis. The method characterizes the compactness of rust layers rather than that of corrosion products removed from the metal surfaces, which is generally practiced in classic N2 adsorption method. Furthermore, the method can reflect the compactness of inner rust layers, to which N2 adsorption is unavailable. The method provides a new approach for the study of rust layers. 展开更多
关键词 Weathering steel Rust layers Ethanol adsorption/dehydration Specific surface area
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Superconductivity in potassium and ammonia co-intercalated FeSe_(1-x)Te_x
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作者 BinBin Xiao NaiZhou Wang +4 位作者 Chao Shang FanBao Meng jianwen ding Bin Lei XiGang Luo 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2019年第4期84-90,共7页
The origin of the ~40 and ~30 K superconducting phases in the metal-intercalated FeSe superconductors is still unclear. We report the synthesis of K_(0.3)(NH_3)_y(FeSe_(1-x)Te_x)_2 and K_(0.6)(NH_3)_y(FeSe_(1-x)Te_x... The origin of the ~40 and ~30 K superconducting phases in the metal-intercalated FeSe superconductors is still unclear. We report the synthesis of K_(0.3)(NH_3)_y(FeSe_(1-x)Te_x)_2 and K_(0.6)(NH_3)_y(FeSe_(1-x)Te_x)_2 with x=0-0.6 by using the liquid ammonia method at room temperature. The superconducting transition temperature Tcof the former remains about 43 K for all the nominal Te content less than 0.3, while that of the latter is about 30 K and obviously decreases with Te doping. Superconductivity disappears for x ≥0.4 in both systems. Except for the different chemical pressure induced by substitution of Te for Se in both systems, we also observed distinct external pressure effect on superconductivity for both systems, with much more efficiency of suppressing Tcby external pressure in the former system. These dramatic differences of both chemical and external pressure effects on Tc between the ~30 and ~40 K superconducting phases revealed that the existence of the two superconducting phases can be ascribed to the moderate and negligible coupling between FeSe layers, respectively. 展开更多
关键词 PNICTIDES and CHALCOGENIDES properties of superconductors effects of pressure methods of MATERIALS synthesis and MATERIALS processing
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