检索结果-南通市图书馆

Broadband high-efficiency dielectric metalenses based on quasi-continuous nanostrips

在线全文

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2024年第5期7卷 43-51页

作者： Xiaohu Zhang Qinmiao Chen Dongliang Tang Kaifeng Liu Haimo Zhang Lintong Shi Mengyao He Yongcai Guo Shumin Xiao key laboratory of optoelectronic Technology and Systems of the Education Ministry of China Chongqing UniversityChongqing 400044China Ministry of Industry and Information Technology key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China key laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial key laboratory of Low-Dimensional Structural physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China

Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical *** broadband and high-efficiency characteristics are highly attractive for the practical implementation of ***,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits *** this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this *** quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally *** quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power *** average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same *** proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.

关键词： broadband high-efficiency metalens sub-diffraction quasi-continuous

Dimensionality-driven metal to Mott insulator transition in two-dimensional 1T-TaSe2

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第3期11卷 108-118页

作者： Ning Tian Zhe Huang Bo Gyu Jang Shuaifei Guo Ya-Jun Yan Jingjing Gao Yijun Yu Jinwoong Hwang Cenyao Tang Meixiao Wang Xuan Luo Yu Ping Sun Zhongkai Liu Dong-Lai Feng Xianhui Chen Sung-Kwan Mo Minjae Kim Young-Woo Son Dawei Shen Wei Ruan Yuanbo Zhang State key laboratory of Surface physics New Cornerstone Science Laboratory and Department of PhysicsFudan University Shanghai Qi Zhi Institute Shanghai Research Center for Quantum Sciences Institute for Nanoelectronic Devices and Quantum Computing Fudan University Zhangjiang Fudan International Innovation Center Fudan University State key laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology(SIMIT)Chinese Academy of Sciences School of Physical Science and Technology ShanghaiTech University Korea Institute for Advanced Study School of Emerging Technology and Department of physics University of Science and Technology of China Advanced Light Source Lawrence Berkeley National Laboratory ShanghaiTech laboratory for Topological physics key laboratory of Materials physics Institute of Solid State Physics Hefei Institutes of Physical ScienceChinese Academy of Sciences High Magnetic Field laboratory Hefei Institutes of Physical Science Chinese Academy of Sciences Collaborative Innovation Centre of Advanced Microstructures Nanjing University Department of physics University of Science and Technology of China and Key Laboratory of Strongly Coupled Quantum Matter Physics Chinese Academy of Sciences National Synchrotron Radiation laboratory University of Science and Technology of China

Two-dimensional materials represent a major frontier for research into exotic many-body quantum phenomena. In the extreme two-dimensional limit, electron-electron interaction often dominates over other electronic energy scales, leading to strongly correlated effects such as quantum spin liquid and unconventional *** dominance is conventionally attributed to the lack of electron screening in the third dimension. Here, we discover an intriguing metal to Mott insulator transition in 1T-TaSe2that defies conventional wisdom. Specifically, we find that dimensionality crossover, instead of reduced screening, drives the transition in atomically thin 1T-TaSe2. A dispersive band crossing the Fermi level is found to be responsible for the bulk metallicity in the material. Reducing the dimensionality,however, effectively quenches the kinetic energy of these initially itinerant electrons, and drives the material into a Mott insulating *** dimensionality-driven metal to Mott insulator transition resolves the long-standing dichotomy between metallic bulk and insulating surface of 1T-TaSe2. Our work further reveals a new pathway for modulating two-dimensional materials that enables exploring strongly correlated systems across uncharted parameter space.

关键词： two-dimensional materials 1T-TaSe2 dimensionality crossover metal to Mott insulator transition

Pyridinic-N doping carbon layers coupled with tensile strain of FeNi alloy for activating water and urea oxidation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第4期9卷 684-694页

作者： Guangfu Qian Wei Chen Jinli Chen Li Yong Gan Tianqi Yu Miaojing Pan Xiaoyan Zhuo Shibin Yin Guangxi key laboratory of Electrochemical Energy Materials College of Chemistry and Chemical EngineeringState Key Laboratory of Processing for Non-Ferrous Metal and Featured MaterialsGuangxi University100 Daxue RoadNanning530004China Institute for Structure and Function and Department of physics Chongqing UniversityChongqing400030China

Exploitation of oxygen evolution reaction(OER)and urea oxidation reaction(UOR)catalysts with high activity and stability at large current density is a major challenge for energy-saving H_(2) production in water ***,we use the pyridinic-N doping carbon layers coupled with tensile strain of FeNi alloy activated by NiFe_(2)O_(4)(FeNi/NiFe_(2)O_(4)@NC)for efficiently increasing the performance of water and urea *** to the tensile strain effect on FeNi/NiFe_(2)O_(4)@NC,it provides a favorable modulation on the electronic properties of the active center,thus enabling amazing OER(η_(100)=196 mV)and UOR(E_(10)=1.32 V)intrinsic ***,the carbon-coated layers can be used as armor to prevent FeNi alloy from being corroded by the electrolyte for enhancing the OER/UOR stability at large current density,showing high industrial *** work thus provides a simple way to prepare high-efficiency catalyst for activating water and urea oxidation.

关键词： Carbon-encapsulated Tensile strain Catalyst Oxygen evolution reaction Urea oxidation reaction

在线全文

学校读者我要写书评

暂无评论

混合溶剂调控插层FeSe基超导体的层间距

Science China Materials 2024年第1期67卷 295-300页

作者：胡国兵石孟竹孟凡保江风云高敏钟钒陈欢郭景锋罗习刚 Physical Science and Technology College Yichun UniversityYichun 336000China key laboratory of strongly coupled Quantum Matter physics Chinese Academy of SciencesHefei National Laboratory for Physical Sciences at Microscaleand Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China

近年来,通过湿化学方法探索合成新型插层FeSe基超导体一直是凝聚态物理的研究热点之一.本文中,我们利用溶剂热离子交换技术成功合成出两种FeSe衍生物:c轴晶胞参数为9.93Å的Li_(0.34)Se_(0.05)(EG)_(0.14)-FeSe和c轴晶胞参数为13.85Å的Li... 详细信息

近年来,通过湿化学方法探索合成新型插层FeSe基超导体一直是凝聚态物理的研究热点之一.本文中,我们利用溶剂热离子交换技术成功合成出两种FeSe衍生物:c轴晶胞参数为9.93Å的Li_(0.34)Se_(0.05)(EG)_(0.14)-FeSe和c轴晶胞参数为13.85Å的Li_(0.21)Se_(0.05)(EG)_(0.26)FeSe.通过调整反应溶剂可以调控以上两种FeSe衍生物的层间距.磁化率和电阻率测试表明它们的超导转变温度(Tc)均为30 K左右,似乎与FeSe层层间距的大小无关.与原始FeSe单晶相比,X射线光电子能谱结果显示FeSe层Fe的价态降低,这表明Tc的提高可能是由于电子掺杂效应引起的.我们的研究为探索合成插层铁基超导体提供了有价值的参考,并为在超导领域探索新型插层材料提供了新的可能性.

关键词：超导转变温度凝聚态物理 X射线光电子能谱铁基超导体混合溶剂离子交换技术湿化学方法反应溶剂

Geant4 simulation of fast-electron bremsstrahlung imaging at the HL-3 tokamak

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第9期35卷 213-229页

作者： Shi-Kui Cheng Yi-Po Zhang Yue-Jiang Shi Jie Zhang Shuai Guan Hong-Bing Xu Qiu-Lei Yang College of Science Chongqing University of TechnologyChongqing 400054China chongqing key laboratory of New Energy Storage Materials and Devices Chongqing 400054China Southwestern Institute of physics Chengdu 610041China Hebei key laboratory of Compact Fusion Langfang 065001China ENN Science and Technology Development Co. Ltd.Langfang 065001China

To further research on high-parameter plasma,we plan to develop a two-dimensional hard X-ray(HXR)imaging system at the HL-3 tokamak to measure HXRs with energies ranging from 20 to 300 *** application of an array-structured detector ensures that this system can measure HXR-radiation spectra from the entire plasma cross ***,it is suitable for the study of fast-electron physics,such as radio-frequency wave current drives,fast electrons driving instabilities,and plasma disruptions in fusion *** this study,we develop a simulation for calculating fast-electron bremsstrahlung in the HL-3 tokamak based on the Monte Carlo simulation code Geant4,in which the plasma geometry and forward scattering of fast-electron bremsstrahlung are *** preliminary calculation results indicate that the HXR energy deposi-tion on the detector is symmetrically distributed,even though the plasma distribution is asymmetric owing to the toroidal *** simulation results are helpful in constructing the relationship between the energy deposition on the detector and parameter distribution on the plasma cross section during HL-3 *** is beneficial for the reconstruction of the fast-electron-distribution function and for optimizing the design of the HXR-imaging system.

关键词： Geant4 simulation HL-3 tokamak Fast-electron bremsstrahlung Hard X-ray imaging

Wave field structure and power coupling features of blue-core helicon plasma driven by various antenna geometries and frequencies

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics B 2024年第3期33卷 480-487页

作者：王超刘佳苌磊卢凌峰张世杰周帆涛 State key laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China Shanghai Institute of Space Propulsion Shanghai 201112China Southwestern Institute of physics Chengdu 610041China

This paper deals with wave propagation and power coupling in blue-core helicon plasma driven by various antennas and *** is found that compared to non-blue-core mode,for blue-core mode,the wave can propagate in the core region,and it decays sharply outside the *** power absorption is lower and steeper in radius for blue-core *** the effects of antenna geometry for blue-core mode,it shows that half helix antenna yields the strongest wave field and power absorption,while loop antenna yields the ***,near axis,for antennas with m=+1,the wave field increases with axial *** the core region,the wave number approaches to a saturation value at much lower frequency for non-blue-core mode compared to blue-core *** total loading resistance is much lower for blue-core *** findings are valuable to understanding the physics of blue-core helicon discharge and optimizing the experimental performance of blue-core helicon plasma sources for applications such as space propulsion and material treatment.

关键词： helicon plasma helicon wave helicon discharge radio frequency plasma source

Persistence of charge density wave against variation of band structures in V_(x)Ti_(1−x)Se_(2)(x=0–0.1)

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第3期17卷 2129-2135页

作者： Zhanfeng Liu Tongrui Li Wen Zhu Hongwei Shou Mukhtar Lawan Adam Qilong Cui Yuliang Li Sheng Wang Yunbo Wu Hongen Zhu Yi Liu Shuangming Chen Xiaojun Wu Shengtao Cui Li Song Zhe Sun National Synchrotron Radiation laboratory CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei 230029China CAS key laboratory of strongly-coupled Quantum Matter physics University of Science and Technology of ChinaHefei 230026China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China State key laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China School of Chemistry and Materials Sciences CAS Key Laboratory of Materials for Energy Conversionand CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei 230026China School Zhejiang Institute of Photonelectronics Jinhua 321004China

Charge density wave(CDW)is a phenomenon that occurs in materials,accompanied by changes in their intrinsic electronic *** study of CDW and its modulation in materials holds tremendous significance in materials research,as it provides a unique approach to controlling the electronic properties of ***_(2) is a typical layered material with a CDW phase at low *** V substitution for Ti in TiSe_(2),we tuned the carrier concentration in V_(x)Ti_(1-x)Se_(2) to study how its electronic structures ***-resolved photoemission spectroscopy(ARPES)shows that the band-folding effect is sustained with the doping level up to 10%,indicating the persistence of the CDW phase,even though the band structure is strikingly different from that of the parent compound TiSe_(2).Though CDW can induce the band fold effect with a driving force from the perspective of electronic systems,our studies suggest that this behavior could be maintained by lattice distortion of the CDW phase,even if band structures deviate from the electron-driven CDW *** work provides a constraint for understanding the CDW mechanism in TiSe_(2),and highlights the role of lattice distortion in the band-folding effect.

关键词： charge density wave band structure lattice distortion

Observational appearance and extra photon rings of an asymmetric thin-shell wormhole with a Bardeen profile

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics C 2024年第6期48卷 211-221页

作者：何柯腱罗智郭森李国平 Department of physics Chongqing UniversityChongqing 401331China Guangxi key laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China School of physics and Astronomy China West Normal UniversityNanchong 637000China

In this work,the optical appearance of an asymmetric thin-shell wormhole with a Bardeen profile is *** initiate the process,we need to construct an asymmetric thin-shell wormhole utilizing the cut-and-paste technique proposed by Visser and subsequently ascertain its pertinent physical quantities such as the radius of the photon sphere and critical impact parameters for different values of magnetic charge ***,the effective potential and motion behavior of photons are also investigated within the framework of asymmetric thin-shell wormholes with a Bardeen *** can be found that the effective potential,ray trajectory,and azimuthal angle of the thin-shell wormhole exhibit a strong correlation with the mass ratio of black *** considering the accretion disk as the sole background light source,we observe additional photon rings and lensing bands in the optical appearance of the asymmetric thin-shell wormhole with a Bardeen profile compared to those exhibited by the Bardeen black *** can find that there is an increase in the size of the specific additional light bands with increasing magnetic charge g,which is different from the black hole *** exceptionally luminous rings can serve as a robust criterion for the identification and characterization of the thin-shell wormhole spacetime.

关键词： shadow asymmetric thin-shell wormhole Bardeen black hole

Deactivation induced by metal sulfate over MnCeOx catalyst in NH_(3)-SCR reaction at low temperature

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第6期42卷 1056-1065,I0002页

作者： Qiao Xie Dongqi An Linsen Zhou Tingzhen Li Zhenghua Hu Menghan Chen Menglan Ma Lei Zhang Jingfang Sun Lin Dong School of Environmental and Chemical Engineering Chongqing Three Gorges UniversityChongqing404000China key laboratory of Water Environment Evolution and Pollution Control in the Three Gorges Reservoir Chongqing Three Gorges UniversityChongqing.404000China Jiangsu key laboratory of Vehicle Emissions Control Center of Modern AnalysisSchool of EnvironmentNanjing UniversityNanjing210093China Institute of Materials China Academy of Engineering PhysicsMianyang621908China

Sulfate adsorption is one of the factors that cause the poisoning of catalyst in the low-temperature NH_(3) selective catalytic reduction reaction(NH_(3)-SCR).In this paper,by controlling the co-adsorption time of SO_(2) and O_(2) at 150℃,a range of sulfated MnCeOx catalysts with different contents of metal sulfate species were prepared to reveal the influence of metal sulfate species content on the catalytic performances and reaction mechanisms at low *** catalytic activity below 250℃rapidly decreases with increasing metal sulfate species *** results of characterizations shed light on the reduction of specific surface area,Mn^(4+)and Ce^(3+)content,and redox ability of MnCeOx owing to the formation of metal sulfate *** experiments reveal that metal sulfate species preferentially absorb on MnOx domains rather than on CeO_(2) domains,and the adsorbed metal sulfate species can suppress the Eley-Rideal and the Langmuir-Hinshelwood reaction mechanisms over the sulfated *** the above results are detrimental to the activity of sulfated MnCeOx in the low-temperature NH3-SCR reaction.

关键词： NH_(3)selective catalytic reduction MnCeOx catalyst Sulfation Low-temperature activity SO_(2)poisoning Rare earths