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Transparent high-performance piezoceramics through pressureless sintering

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Journal of Advanced Ceramics 2024年第5期13卷 561-567页

作者： Hye-Lim Yu Woo-Seok Kang Ju-Hyeon Lee Temesgen Tadeyos Zate young-Jin Lee Bo-kun Koo Dong-Jin Shin Min-Soo Kim Soon-Jong Jeong young Ghyu Ahn Wook Jo Department of Material Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Energy Conversion Research Center Korea Electrotechnology Research InstituteChangwon 51543Republic of Korea MLCC Development Team Component Biz.UnitSamsung Electro-Mechanics Co.Ltd.Suwon 16674Republic of Korea

Piezoelectricity offers an electromechanical coupling that is widely utilized in transducer *** has been a consistent demand for transparent piezoelectric materials for optoelectrical ***,despite the inherent tradeoff between the transparency and the piezoelectricity,numerous strategies have been explored to develop the transparent piezoelectric ***,the most transparent piezoelectric materials developed to date is either a single crystal or materials that achieve transparency via hot-press sintering,limiting its industrial ***,we introduce a novel piezoelectric material that ensures transparency through co-doping and pressureless sintering of polycrystalline *** this study,we employed a compositional optimization approach to enhance the synergistic effect between the transparency and the piezoelectric properties of 0.71Pb(Mg_(1/3)Nb_(2/3))O_(3)–0.29PbTiO_(3)(PMN–0.29PT)*** utilizing the tape casting process for mass production and large-area manufacturing,our Pb_(0.913)La_(0.0145)Sm_(0.0145)(Mg_(1/3)Nb_(2/3))_(0.71)Ti_(0.29)O_(3)(TP2.9)ceramics exhibited over 60%transparency and large piezoelectric coefficient(d33)of 1104 pC/*** material holds considerable promise for a wide range of industrial applications in both the optical and electronic domains.

关键词： piezoelectric ceramics transparency pressureless sintering co-doping tape casting

Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

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Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： Se Hyun Kim younghwan Lee Dong Hyun Lee Geun Hyeong Park Hyun Woo Jeong kun Yang Yong Hyeon Cho young Yong Kim Min Hyuk Park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Inter-university Semiconductor Research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization

Adaptive Consensus of Uncertain Multi-Agent Systems With Unified Prescribed Performance

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1310-1312页

作者： kun Li Kai Zhao Yongduan Song The authors are with the School of Automation Chongqing UniversityChongqing 400044China

Dear Editor,An adaptive consensus control algorithm for uncertain multi-agent systems(MAS),capable of guaranteeing unified prescribed performance,is presented in this *** many existing prescribed performance related works,the developed control exhibits some ***,a distributed prescribed time observer is introduced so that not only each follower is able to estimate the leader’s signal within a predetermined time,but also the control design for each agent is independent with its neighbors.

关键词： agent prescribed Uncertain

Effect of Ti_(p) Content on the Work Hardening and Softening Behavior of Mg-Zn-Ca Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 551-560页

作者： Jin-Kai Zhang Cui-Ju Wang Yi-Dan Fan Chao Xu Kai-Bo Nie kun-kun Deng Shanxi Key Laboratory of Advanced Magnesium-Based Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring *** extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyzed compared with the ZX60(Mg-6Zn-0.2Ca)*** results showed that the addition of Ti_(p) could not only promote the nucleation of dynamic recrystallized(DRXed)grains,but also be propitious to the refinement of DRXed *** increasing Ti_(p) content,the size of DRXed grains decreased accompanied with increasing volume fraction of DRXed *** the Ti_(p) content increased to 15 vol.%,the average size and volume fraction of DRXed grains reached to~0.32μm and 93.2%,***,both the strength and elongation were improved by the addition of Ti_(p).With increasing content of Ti_(p),a substantial increase in the strength was achieved with little change in the ***,the elongation decreased sharply when the Ti_(p) content further increased to 15 vol.%.The addition of Ti_(p) led to an increase in the work hardening rate,which gradually increased with increasing Ti_(p) ***,the softening rate did not demonstrate the same tendency with increasing Ti_(p) *** the conventional ceramic particles,the Ti_(p) can be deformed in coordination with the matrix alloy,which imparted a higher softening rate to the matrix *** though the softening rate improved as the Ti_(p) content increased from 5 to 10 vol.%,it dropped deeply as the Ti_(p) content increased to 15 vol.%owing to the fracture of Ti_(p) during extrusion.

关键词： Titanium particle content Particle reinforced magnesium matrix composites Work hardening Softening behavior Mechanical properties

Effects of Interaction between Axial and Radial Secondary Air and Reductive Intensity in Reduction Region on Combustion Characteristics and NO_(x) Emission of Coal Preheated by a Self-Preheating Burner

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Journal of Thermal Science 2024年第1期33卷 249-267页

作者： SU kun DING Hongliang OUYANG Ziqu ZHANG Jinyang ZHU Shujun Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China

The study focused on the effects of the interaction between axial and radial secondary air and the reductive intensity in reduction region on combustion characteristics and NO_(x) emission in a 30 kW preheating combustion *** results revealed that the interaction and reductive intensity influenced the combustion in the down-fired combustor(DFC) and NO_(x) emission *** the temperature distribution,the interaction caused the position of the main combustion region to shift down as R_(2-12)(ratio of axial secondary air flow to radial secondary air flow) decreased or λ_(2)(total secondary air ratio) increased,and there was the interplay between both of their *** R_(3-12)(ratio of first-staged tertiary air flow to second-staged tertiary air flow)increased,the decrease in the reductive intensity also caused the above phenomenon,and the peak temperature increased in this *** the NO_(x) emission,the interaction affected the NO_(x) reduction adversely when λ_(2) or R_(2-12) was higher,and the range of this effect was larger,so that the NO_x emission increased obviously as they *** decrease in the reductive intensity caused the NO_(x) emission increased under the homogeneous reduction mechanism,while was unchanged at a high level under the heterogeneous reduction *** the combustion efficiency,the interaction improved the combustion efficiency as λ_(2) increased when R_(2-12) was lower,while reduced it as λ_(2) increased excessively when R_(2-12) was *** proper decrease in the reductive intensity caused the combustion efficiency increased obviously,while was hardly improved further when the intensity decreased *** this study,the lowest NO_(x) emission was only 41.75 mg/m^(3) without sacrificing the combustion efficiency by optimizing the interaction and reductive intensity.

关键词： self-preheating interaction of axial and radial secondary air reductive intensity combustion characteristic NO_(x)emission

Effect of annealing temperature on microstructure and mechanical properties of Mg-Zn-Zr-Nd alloy with large final rolling deformation

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Journal of Central South University 2024年第6期31卷 1774-1789页

作者： ZHANG Jin-hai NIE Kai-bo ZHANG Jin-hua DENG kun-kun LIU Zhi-long College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of High-end Compressor and System Technology Hefei 230031China

In this study,the Mg-3Zn-0.5Zr-χNd(χ=0,0.6)alloys were subjected to final rolling treatment with large deformation of 50%.The impact of annealing temperatures on the microstructure and mechanical properties was *** rolled Mg-3Zn-0.5Zr-0.6Nd alloy exhibited an ultimate tensile strength of 386 MPa,a yield strength of 361 MPa,and an elongation of 7.1%.Annealing at different temperatures resulted in reduced strength and obviously increased elongation for both *** mechanical properties for the Mg-3Zn-0.5Zr-0.6Nd alloy were achieved after annealing at 200℃,with an ultimate tensile strength of 287 MPa,a yield strength of 235 MPa,and an elongation of 26.1%.The numerous deformed microstructures,twins,and precipitated phases in the rolled alloy could impede the deformation at room temperature and increase the work hardening *** annealing,a decrease in the work hardening effect and an increase in the dynamic recovery effect were obtained due to the formation of fine equiaxed grains,and the increased volume fraction of precipitated phases,which significantly improved the elongation of the ***,the addition of Nd element could enhance the annealing recrystallization rate,reduce the Schmid factor difference between basal and prismatic slip systems,facilitate multi-system slip initiation and improve the alloy plasticity.

关键词： Mg-Zn-Zr-Nd alloy large final rolling deformation annealing temperatures microstructures mechanical properties

Heat distribution model under hydrogen-rich low-carbon conditions in blast furnace

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Journal of Iron and Steel Research(International) 2024年第3期31卷 584-594页

作者： Gang Wang Jun Xu kun He Zhong-ping Zou Hao Bai School of Metallurgy and Ecological Engineering University of Science and Technology BeijingBeijing 100083China CISDI Low-Carbon Blast Furnace Research Office MCC Low-Carbon Technology Research InstituteChongqing 401122China

Low carbon development of blast furnaces is one of the key technological directions in the current development of *** to the differences in the physical and chemical properties of hydrogen and carbon,hydrogen-rich media entering a blast furnace will change the heat distribution,thus affecting the stability of ***,a heat distribution model was proposed to study the temperature distribution in a blast furnace,simultaneously considering gas-solid heat exchange,slag and iron melting,and chemical *** model was used to analyze the temperature distribution of a 2300 m^(3) blast furnace and was verified via comparison with actual production ***,the effects of the injection rate of hydrogen-rich media,H2 concentration,and oxygen enrichment rate of the blast on the temperature distribution were *** indicated that the increase in the injection rate of the hydrogen-rich media decreased the amount of direct reduction and led to an increase in the furnace ***,an increase in the oxygen enrichment rate led to a decrease in the furnace temperature,but could reduce the solid fuel ratio,while the change in H2 concentration had less effect on the temperature *** combination of hydrogen-rich media injection and the increase in the oxygen enrichment rate would help to adjust the temperature distribution to the same level as the conventional blast furnace conditions.

关键词： Heat distribution Blast furnace Low-carbon condition Hydrogen enrichment Calculation model

TROPICAL CYCLOGENESIS DETECTION IN NWP AT KMA

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Tropical Cyclone Research and Review 2014年第4期3卷 256-269页

作者： Woojeong Lee KiRyong Kang Jiyoung Kim kun-young byun Jong Sook Park Seonghee Won Yunho Park WonTae Yun National Typhoon Center Korea Meteorological AdministrationJejuKorea Weather Radar Center Korea Meteorological AdministrationSeoulKorea Global Environment System Research Division National Institute Meteorological ResearchKorea Meteorological AdministrationJejuKorea Foreast Research Division National Institute Meteorological ResearchKorea Meteorological AdministrationJejuKorea Numerical Model Development Division Korea Meteorological AdministrationSeoulKorea

In this study,a tropical cyclogenesis detection system,Tropical Cyclone Analysis&Forecast(TCAF),was evaluated with an operational numerical model of the Korea Meteorological Administration(KMA).The tracking performance was compared with the result with the ECMWF model input field(TCAF-ECMWF).In order to improve the performance,different tracking time at an interval of 6 hours were *** lowest false alarm rate and the highest hit rate(correct detection)were achieved at 06 hour after the initial tracking *** tracking performance was also tested on two typhoons in 2013,LEEPI(1304)and DANAS(1324).The results showed that the TCAF-ECMWF detected tropical depressions 72 hours before the formation of the typhoon DANAS,which is a 12-hour earlier detection compared with the current performance with the use of KMA’s numerical weather prediction(NWP)model ***,it is expected that TC genesis detection could be improved by determining an optimal tracking time and by using more accurate NWP model data.

关键词： tropical cyclone genesis detection numerical weather prediction

Review on frost resistance and anti-clogging of pervious concrete

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 481-496页

作者： Zhuo Wang Zhichen Liu Feng Zeng kun He Shuaicheng Guo China Railway Construction Group Co. Ltd.Beijing 100040China State Key Laboratory of Bridge Safety and Resilience College of Civil EngineeringHunan UniversityChangsha 410082China

Pervious concrete is a special type of concrete that is of high porosity and contains no or a small amount of fine aggregate,and it is an important basic material for sponge city *** presence of a large number of connected pores inside pervious concrete leads to a marked difference in durability failure mechanism compared with that of ordinary *** this study,the frost resistance and anti-clogging of pervious concrete were introduced in detail,and the methods to improve their performance were summarized *** cracking pattern of pervious concrete is influenced by geometric characteristics and three-dimensional morphological features of pores,resulting in its crack generation,development,and geometry being significantly different from those of ordinary concrete,thus leading to different freeze-thaw cycle *** addition,due to its different pore structure compared to ordinary concrete,three types of clogging mechanisms,affecting the long-term permeability of pervious concrete were elaborated systematically(i.e.,physical clogging,biological clogging,and chemical clogging).And the ways to improve the anti-clogging of pervious concrete are systematically presented from multiple ***,in order to broaden the engineering applications of pervious concrete,some research proposals are presented in this study.

关键词： Pervious concrete Connected pore Frost resistance Clogging mechanism