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钙钛矿CsPbX_(3)(X=Cl,Br,I)与五环石墨烯范德瓦耳斯异质结的界面相互作用和光电性能的第一性原理研究

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物理学报 2021年第5期70卷 269-277页

作者：吴甜姚梦丽龙孟秋中南大学物理与电子学院长沙410083 中南大学先进材料超微结构与超快过程研究所长沙410083

异质结工程是一种提高半导体材料光电性能的有效方法.本文构建了全无机钙钛矿CsPbX_(3)(X=Cl,Br,I)和二维五环石墨烯penta-graphene(PG)的新型范德瓦耳斯(vdW)异质结,利用第一性原理研究了CsPbX_(3)-PG异质结不同界面接触的稳定性,进而... 详细信息

异质结工程是一种提高半导体材料光电性能的有效方法.本文构建了全无机钙钛矿CsPbX_(3)(X=Cl,Br,I)和二维五环石墨烯penta-graphene(PG)的新型范德瓦耳斯(vdW)异质结,利用第一性原理研究了CsPbX_(3)-PG异质结不同界面接触的稳定性,进而计算了稳定性较好的Pb-X接触界面异质结的电子结构和光电性能.研究结果表明,CsPbX_(3)-PG(X=Cl,Br,I)异质结具有II型能带排列特征,能级差距由Cl向I逐渐缩小,具有良好的光生载流子分离能力和电荷输运性质.此外,研究发现CsPbX_(3)-PG异质结能有效拓宽材料的光吸收谱范围,并能显著提高其光吸收能力,尤其是CsPbI_(3)具有最优的光吸收性能.经理论估算,CsPbX_(3)-PG的光电功率转换效率(PCE)可高达21%.这些结果表明,全无机金属卤化物钙钛矿CsPbX_(3)-PG异质结可以有效地提高半导体材料的光电性能,预期在光电转换器件中具有重要的应用潜力.

关键词：钙钛矿CsPbX_(3) 五环石墨烯范德瓦耳斯异质结光电性能

Modulated thermal transport for flexural and in-plane phonons in double-stub graphene nanoribbons

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Chinese Physics B 2018年第8期27卷 566-571页

作者： Chang-Ning Pan meng-qiu long JuJa He Hunan Key Laboratory of Super Micro-structure and Ultrafast Process School of Physics and Electronics Central South UniversityChangsha 410083China School of Science Hunan University of TechnologyZhuzhou 412008China

Thermal transport properties are investigated for out-of-plane phonon modes （FPMs） and it-plane phonon modes （IPMs） in double-stub graphene nanoribbons （GNRs）. The results show that the quantized thermal conductance plateau of FPMs is narrower and more easily broken by the double-stub structure. In the straight GNRs, the thermal conductance of FPMs is higher in the low temperature region due to there being less cut-off frequency and more low-frequency excited modes. In contrast, the thermal conductance of IPMs is higher in the high temperature region becau~,＇.e of the wider phonon energy spectrum. Furthermore, the thermal transport of two types of phonon modes can be modulated by the double-stub GNRs, the thermal conductance of FPMs is less than that of IPMs in the low temperatures, but it dominates the contribution to the total thermal conductance in the high temperatures. The modulated thermal conclu~＇tanc：e can provide a guideline for designing high-performance thermal or thermoelectric nanodevices based on graphene.

关键词： graphene nanoribbon flexural phonons in-plane phonons thermoelectric properties

Fano Resonance Effect in CO-Adsorbed Zigzag Graphene Nanoribbons

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Chinese Physics Letters 2017年第9期34卷 91-94页

作者： Gao Wang meng-qiu long Dan Zhang Advanced Research Center Central South University Changsha 410083 Institute of Super Microstructure and Ultrafast Process Central South University Changsha 410083 School of Science Hunan University of Technology Zhuzhou 412007

Quantum interference plays an important role in tuning the transport property of nano-devices. Using the non- equilibrium Green＇s Function method in combination with density functional theory, we investigate the influence to the transport property of a CO molecule adsorbed on one edge of a zigzag graphene nanoribbon device. Our results show that the CO molecule-adsorbed zigzag graphene nanoribbon devices can exhibit the Fano resonance phenomenon. Moreover, the distance between CO molecules and zigzag graphene nanoribbons is closely related to the energy sites of the Fano resonance. Our theoretical analyses indicate that the Fano resonance would be attributed to the interaction between CO molecules and the edge of the zigzag graphene nanoribbon device, which results in the localization of electrons and significantly changes the transmission spectrum.

关键词： DOS Fano Resonance Effect in CO-Adsorbed Zigzag Graphene Nanoribbons CO

Investigation of straightforward impedance eduction method on single-degree-of-freedom acoustic liners

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Chinese Journal of Aeronautics 2018年第12期31卷 2221-2233页

作者： Xianghai qiu Bo XIN long WU Yang meng Xiaodong JING Fluid and Acoustic Engineering Laboratory School of Energy and Power Engineering Beihang University

In order to address the current aircraft noise problem, the knowledge of impedance of acoustic liners subjected to high-intensity sound and grazing flow is of crucial importance to the design of high-efficiency acoustic nacelles. To this end, the present study is twofold. Firstly, the StraightForward impedance eduction Method(SFM) is evaluated by the strategy that the impedance of a liner specimen is firstly experimentally educed on a flow duct using the SFM, and then its accuracy is checked by comparing the numerical prediction with the measured wall sound pressure of the flow duct. Secondly, the effects of grazing flow and high-intensity sound on the impedance behavior of two single-layer liners are investigated based on comparisons between educed impedance and predictions by three impedance models. The performance of the SFM is validated by showing that the educed impedance leads to excellent agreement between the simulation and the measured wall sound pressure for different grazing flow Mach numbers and Sound Pressure Levels(SPLs) and over a frequency range from 3000 Hz down to 500 Hz. The grazing flow effect generally has the tendency that the acoustic resistance exhibits a slight decrease before it increases linearly with an increase in Mach,predicted successfully by the sound-vortex interaction theoretical model and the Kooi semi-empirical impedance model. However, the Goodrich semi-empirical impedance model gives only a simple linear relation of acoustic resistance starting from Mach zero. Additionally, when the SPL increases from 110 to 140 d B in the present investigation, the acoustic resistance exhibits a significant increase at all frequencies in the absence of flow; however, the resistance decreases slightly under a grazing flow of Mach 0.117. It indicates that the SPL effect can be greatly inhibited when flow is present,and the grazing flow effect can be reduced partly as well at a relatively high SPL.

关键词： Acoustic liner Experimental validation Grazing flow effect High sound intensity effect Impedance eduction Numerical evaluation Straightforward impedance eduction method

The Emergence of Functional Ultrasound for Noninvasive Brain-Computer Interface

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Research 2024年第2期6卷 301-317页

作者： Hairong Zheng Lili Niu Weibao qiu Dong Liang Xiaojing long Guanglin Li Zhiyuan Liu long meng Institute of Biomedical and Health Engineering Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Shenzhen Institute of Advanced Integration Technology Chinese Academy of Sciences and The Chinese University of Hong KongShenzhen518055China

A noninvasive brain-computer interface is a central task in the comprehensive analysis and understanding of the brain and is an important challenge in international brain-science *** implanted brain-computer interfaces are cranial and invasive,which considerably limits their *** development of new noninvasive reading and writing technologies will advance substantial innovations and breakthroughs in the field of brain-computer ***,we review the theory and development of the ultrasound brain functional imaging and its ***,we introduce latest advancements in ultrasound brain modulation and its applications in rodents,primates,and human;its mechanism and closed-loop ultrasound neuromodulation based on electroencephalograph are also ***,high-frequency acoustic noninvasive brain-computer interface is prospected based on ultrasound super-resolution imaging and acoustic tweezers.

关键词： breakthrough computer Computer

Management and Reconfiguration of a Radiology Department under the Threat of Coronavirus Disease 2019:Experience from Wuhan

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Current Medical Science 2020年第4期40卷 608-613页

作者： meng TIAN Cong-cong LIU Lu long qiu-xia WANG Department of Radiology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430000China Department of Epidemiology and Biostatistics West China School of Public HealthSichuan UniversityChengdu 610000China

Summary:The corona virus disease 2019(COVID-19)is an emerging respiratory infectious disease caused by SARS-CoV-2,which first occurred in December 2019 in Wuhan,*** days,in China,chest CT is used for diagnosis of COVID-19,as an important complement to the reverse-transcription polymerase chain reaction(RT-PCR)*** of contacting with a large number of suspected or probable cases closely during chest CT examination,radiographers are easily infected with *** article included the rearrangement of CT examination room in fever clinic,the rearrangement of human resources in radiology department,and the drafting of new operating procedures for radiologists who carry out CT examination on COVID-19 *** article also introduced the emergency management procedures of the department of radiology during the outbreak,and the experience of infection prevention for the staff of the department of radiology.

关键词： COVID-19 management reconfiguration radiology department

Covalent coupling of DNA bases with graphene nanoribbon electrodes: Negative differential resistance, rectifying, and thermoelectric performance

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Chinese Physics B 2020年第10期29卷 418-427页

作者： Peng-Peng Zhang Shi-Hua Tan Xiao-Fang Peng meng-qiu long Hunan Provincial Key Laboratory of Materials Surface or Interface Science and Technology Central South University of Forestry and TechnologyChangsha 410004China School of Physics and Electronics Central South UniversityChangsha 410083China

By applying nonequilibrium Green's functions in combination with the density-functional theory, we investigate the electronic, thermal, and thermoelectric properties of four kinds of bases in DNA perpendicularly coupling between two ZGNR electrodes. The results show that the electron transport is highly sensitive to different base-ZGNR coupling geometries, and the system can present large rectifying and negative differential resistance effects. Moreover, the fluctuations of electronic transmission and super-low thermal conductance result in significant enhancement of the thermoelectric figure of merit (ZT): the ZT will be over 1.4 at room temperature, and over 1.6 at 200 K. The results show that the base-ZGNR coupling devices can present large rectifying, negative differential resistance, and enhanced thermoelectric effects.

关键词： DNA bases graphene electron transport phonon transport thermoelectric performance

Electronic and Thermoelectric Properties in SnS-Nanoribbon-Based Heterojunctions

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Chinese Physics Letters 2024年第9期41卷 63-68页

作者： Kai-Bo Zhang Shi-Hua Tan Xiao-Fang Peng meng-qiu long Hunan Province Key Laboratory of Materials Surface or Interface Science and Technology Central South University of Forestry and TechnologyChangsha 410004China School of Physics and Electronics Central South UniversityChangsha 410083China

As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric *** extensive research on the thermoelectric properties of this material in recent years,the room-temperature thermoelectric figure of merit(ZT)of SnS has not been broke through 2[2022 *** Mater.651143].In this work,based on a combination of density functional theory and non-equilibrium Green’s function method,the electronic and thermoelectric properties in SnS-nanoribbon-based heterojunctions are *** results show that although SnS nanoribbons(SNSNRs)with zigzag edges(ZSNSNRs)and armchair edges(ASNSNRs)both have semiconductor properties,the bandgaps of ASNSNRs are much wider than those of ZSNSNRs,which induces much wider conductance gaps of𝑁N-ASNSNR(N is the number of tin-sulfide lines across the ribbon width)).In the positive energy region,the ZT peaks of𝐿L-SNS-Au are much larger than those of𝐿L-SNS-GNR(L represents the number of longitudinal repeating units of SNSNR in the scattering region).While in the positive energy region,the ZT peaks of L-SNSGNR are larger than those of *** calculations reveal that the figure of merit will be over 3.7 in L-SNS-Au and 2.2 in L-SNS-GNR at room temperature,and over 4 in L-SNS-Au and 2.6 in L-SNS-GNR at 500 K.

关键词： material sulfide ribbon

Seismicity changes and numerical simulation of coseismic deformation following the 2022 M_(s)6.8 Luding earthquake in Sichuan,China

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Science China Earth Sciences 2024年第8期67卷 2507-2521页

作者： qiu meng Zitao WANG Huai ZHANG Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Earth Critical Zone National Research Station Beijing 101408China

The Xianshuihe fault is a major tectonic boundary between the Sichuan-Yunnan rhombic and Bayanhar blocks in Southwest *** an average left-lateral strike-slip movement of 10–15 mm/yr,it is a fast-moving strike-slip continental *** September 5,2022,the Ms6.8 Luding earthquake occurred along the Moxi segment of the Xianshuihe fault,reaching a maximum intensity of IX and resulting in a significant number of casualties and severe property *** earthquake broke the long-standing seismic quiescence of the Xianshuihe fault,which lasted for more than 40 years,and was followed by a significant number of *** outstanding question is how the behavior of the Xianshuihe fault and major earthquakes changed following this *** this study,we examined the changes in regional seismicity following the Luding earthquake and identified the potential for future strong earthquakes along the Xianshuihe *** used a finite element numerical method to simulate the environment of the seismogenic fault and its adjacent *** addition,we used the coseismic slip model of the Luding earthquake with the split-node method to calculate how the stress and strain fields in the surrounding area were affected by the2022 *** stress changes were resolved in the main faults,and the seismicity of adjacent faults was analyzed in conjunction with the observed seismic *** results indicate that regional tectonic movement primarily occurred to the southeast along the Moxi *** stress field is approximately north-south in tension and east-west in *** in the stress field in the epicentral region of the Luding earthquake exceeded 1 *** maximum displacement of the coseismic deformation field was concentrated between Moxi town and Tuanjie village,and the Coulomb stress of the fault zone in this region experienced the largest ***,the b-value of the Gutenberg-Richter magnitude-frequency relationship at the epicenter a

关键词： Luding earthquake Seismicity Coulomb failure stress change Finite element numerical simulation