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Chinese physics B 2024年第4期33卷 640-648页

作者：陈登辉羊志付新宇秦申奥严岩王传奎李宗良邱帅 Shandong Key Laboratory of Medical physics and Image Processing&Shandong Provincial Engineering and technical Center of Light Manipulations School of Physics and ElectronicsShandong Normal UniversityJinan 250358China

Orientation-dependent transport properties induced by anisotropic molecules are enticing in single-molecule junctions.Here,using the first-principles method,we theoretically investigate spin transport properties and photoresponse characteristics in trimesic acid magnetic single-molecule junctions with different molecular adsorption orientations and electrode contact sites.The transport calculations indicate that a single-molecule switch and a significant enhancement of spin transport and photoresponse can be achieved when the molecular adsorption orientation changes from planar geometry to upright geometry.The maximum spin polarization of current and photocurrent in upright molecular junctions exceeds 90%.Moreover,as the Ni tip electrode moves,the tunneling magnetoresistance of upright molecular junctions can be increased to 70%.The analysis of the spin-dependent PDOS elucidates that the spinterfaces between organic molecule and ferromagnetic electrodes are modulated by molecular adsorption orientation,where the molecule in upright molecular junctions yields higher spin polarization.Our theoretical work paves the way for designing spintronic devices and optoelectronic devices with anisotropic functionality base on anisotropic molecules.

关键词： molecular spintronics spin polarization tunneling magnetoresistance photocurrent single-molecule junctions

QCD sum rule study of J^(P)=1^(±)exotic states with two heavy quarks in the molecular picture

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Chinese physics C 2024年第6期48卷 31-37页

作者： T.M.Aliev S.Bilmis M.Savcı Department of physics Middle East Technical UniversityAnkara06800Turkey TUBITAK ULAKBIM Ankara06510Turkey

In this study,the spectroscopic parameters of exotic molecular states composed of mesons containing two heavy quarks(scalar-axial and pseudoscalar-axial meson combinations)are investigated within the QCD sum rules.Our findings reveal that molecular states containing charm quarks do not form bound states,whereas states with b-quarks can form exotic molecular states.This observation has significant implications for understanding the structure of these exotic states.

关键词： QCD sum rules exotic mesons molecular states

Remote sensing of air pollution incorporating integrated-path differential-absorption and coherent-Doppler lidar

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Defence Technology（防务技术） 2024年第1期31卷 594-601页

作者： Ze-hou Yang Yong Chen Chun-li Chen Yong-ke Zhang Ji-hui Dong Tao Peng Xiao-feng Li Ding-fu Zhou School of physics Beijing Institute of TechnologyBeijing 100081China Southwest Institute of technical physics Chengdu 610041SichuanChina School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China

An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and demonstrated.The system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber laser.By combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric pollution.Extensive static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 km.Flight experiments is conducted with the helicopter.Scanning of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 s.The test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.

关键词： Differential absorption LIDAR Coherent Doppler lidar Remoting sensing Atmospheric pollution

Magnesium oxide(MgO) nanoadsorbents in wastewater treatment: A comprehensive review

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Journal of Magnesium and Alloys 2024年第5期12卷 1709-1773页

作者： H.C.S.Perera V.Gurunanthanan Anoop Singh M.M.M.G.P.G.Mantilaka G.Das Sandeep Arya Department of physics Khalifa University Postgraduate Institute of Science University of Peradeniya Department of Humanities and Sciences Guru Nanak Institutions Technical Campus Centre for Global Health Research Saveetha Medical College and Hospitals Saveetha Institute of Medical and Technical Sciences Department of physics University of Jammu

Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge, necessitating effective and sustainable separation techniques. This review article provides a detailed examination of magnesium oxide(MgO) nanoparticles as an innovative nanoadsorbent for wastewater treatment, with a specific focus on heavy metal and dye removal. The review comprehensively explores various aspects of MgO nanoparticles, including their structural characteristics and synthesis techniques. The article delves into the morphology and crystallographic arrangement of MgO nanoparticles, offering insights into their structural attributes. Given the complexity of adsorption processes, the review identifies and analyzes parameters influencing the adsorption efficiency of MgO nanoparticles, such as temperature, pH, contact time, initial concentration, and co-existing ions. The interplay between these parameters and the adsorption capability of MgO nanoparticles emphasizes the importance of optimizing operational conditions. Furthermore, the review assesses various synthesis methods for MgO nanoparticles, including sol-gel, hydrothermal, precipitation, green synthesis, solvothermal, and template-assisted techniques. It discusses the advantages, limitations, and resulting nanoparticle characteristics of each method, enabling readers to grasp the implications of synthesis processes on adsorption efficiency. This comprehensive review consolidates current insights into the effectiveness of MgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to MgO nanoparticles. Moreover, there is a need to investigate the use of MgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.

关键词： MgO nanoparticles Nanoadsorbent Wastewater treatment Heavy metals Dye separation Adsorption Synthesis methods

Probing valence quark width of the proton in deeply virtual Compton scattering at high energies

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Chinese physics C 2024年第5期48卷 235-243页

作者：向文昌曹德文周代翠 physics division Guangzhou Maritime UniversityGuangzhou 510725China Key Laboratory of Quark and Lepton physics(MOE) and Institute of Particle PhysicsCentral China Normal UniversityWuhan 430079China

We use the refined hot spot model to study the valence quark shape of the proton with the deeply virtual Compton scattering at high energies in the color glass condensate framework.To investigate the individual valence quark shape,a novel treatment of the valence quark width is employed.We calculate the cross-sections for coherent and incoherent deeply virtual Compton scattering using,for the first time,different widths(Bu and Bd)for the profile density distributions of the up and down quarks instead of using the same width as in the literature.We find that the cross-sections calculated with Bu≥Bd at each collision energy are consistent with each other,which is in agreement with theoretical expectations,whereas those computed with Bu

关键词： gluon saturation physics color glass condensate proton shape fluctuations

Even-odd layer-dependent multiferroic in freestanding rare-earth orthorhombic perovskite

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Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 151-157页

作者： Shaowen Xu Fanhao Jia Ning Dai School of physics and Optoelectronic Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Department of physics College of ScienceHangzhou Dianzi UniversityHangzhou 310018China State Key Laboratory of Infrared physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

Freestanding oxide perovskites possess strong interlayer coupling between adjacent atomic layers,thus exerting a determinative effect on the magnetism and ferroelectricity of these atomic-scale materials.Here,we propose an effective strategy to manipulate magnetism and ferroelectricity in freestanding rare-earth orthorhombic perovskite via modulation of layer thickness.By performing first-principles calculations,an even-odd oscillation is demonstrated in few-layer GdAlO_(3)perovskite(GAP).Specifically,odd-layer systems with charged atomic layers are ferromagnetic polar metals,while even-layer systems are antiferromagnetic ferroelectric semiconductors.This thickness-dependent magnetic phase transition originates from carrier doping,as rationalized by the Stoner criterion.Furthermore,we demonstrate the promotion of in-plane ferroelectricity via the concurrent application of two distinct antiferrodistortive displacements,each driven by formation and breaking of bonds.Analogous multiferroic phases may emerge in other transition metal oxide perovskites supporting multiple valence states,e.g.,few-layer Gd MO_(3)(M=V,Cr,Mn,and Ni).This work puts forward a strategy for layer thickness engineering of magnetism and ferroelectricity in 2D oxide perovskite multiferroic materials.

关键词： few-layer rare-earth perovskite multiferroicity size effect first principles calculations

Thermal Performance of a 4 K High-Frequency Pulse Tube Cryocooler with Different Working Fluids

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Journal of Thermal Science 2024年第4期33卷 1468-1479页

作者： GAO Zhaozhao YANG Biao FAN Xiaoyu CHEN Liubiao WANG Junjie Key Laboratory of Cryogenic Science and Technology Technical Institute of Physics and ChemistryChinese Academy of Sciences University of Chinese Academy of Sciences

The high-frequency pulse tube cryocooler（HPTC） represents a promising miniature cryocooling technology due to its compact structure and the absence of low-temperature moving components.However,limited to the non-ideal gas effect of4He,the HPTC is hard to obtain high cooling performance in the liquid helium temperature range.3He as the working fluid can effectively improve the cooling performance of the HPTC,but the high cost hinders its wide application.In consideration of both cooling performance and cost-effectiveness,this paper explores the feasibility of utilizing3He-4He mixtures as the working fluid for HPTCs.Firstly,the experimental results of a developed HPTC based4He are reported.With a total power consumption of 575 W,the lowest temperature of 3.26 K was observed.And the measured cooling power at 4.2 K was 20.8 mW.Then the theoretical utmost efficiency of the cryocooler was calculated in terms of the thermophysical properties of the working fluids,using3He-4He mixtures with different compositions as the working fluids.The whole machine modeling of the HPTC was further carried out,and the influence of the working fluids with different components on the structural parameters such as double-inlet and inertance tube,and operating parameters such as pressure and frequency were analyzed.The calculated results show that the cooling power is expected to be increased to36 mW and 53 mW if the equimolar3He-4He mixture and pure3He are used,respectively.

关键词： high-frequency pulse tube cryocooler 3 He- 4 He mixture liquid helium temperature thermally coupled

On-Chip Micro Temperature Controllers Based on Freestanding Thermoelectric Nano Films for Low-Power Electronics

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Nano-Micro Letters 2024年第7期16卷 98-108页

作者： Qun Jin Tianxiao Guo Nicolas Perez Nianjun Yang Xin Jiang Kornelius Nielsch Heiko Reith Institute for Metallic Materials Leibniz Institute for Solid State and Materials Research01069 DresdenGermany Institute of Materials Engineering University of Siegen57076 SiegenGermany Institute of Applied physics Technical University of Dresden01069 DresdenGermany Institute of Materials Science Technical University of Dresden01069 DresdenGermany

Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.

关键词： Temperature control Low-power electronics On-chip micro temperature controller Freestanding thermoelectric nano films Temperature-sensitive components

Highly efficient tunable photodetector with a bipolar response in van der Waals heterojunctions

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Science China(Technological Sciences) 2024年第2期67卷 639-646页

作者： SHI ChaoFan ZHANG Shi XIAO KeNing ZHANG LiBo HAN Li ZHU YuLin TANG WeiWei LIU ChangLong LI GuanHai CHEN XiaoShuang College of physics and Optoelectronic Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences Hangzhou310024China State Key Laboratory of Infrared physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

The heterojunction integration of two-dimensional(2D)materials via van der Waals(vdW)forces,unencumbered by lattice and processing constraints,constitutes an efficacious approach to enhance the overall optoelectronic performance of photodetectors,due to an assortment of distinctive light-matter interactions.Nonetheless,vdW heterojunction photodetectors based on transition metal dichalcogenides(TMDs)face an inevitable trade-off between low dark currents and high responsivity,curtailing the application potential of myriad novel optoelectronic components in sensing,spectral,and communication systems.In this study,we present the successful actualization of a highly sensitive,self-powered,and gate-tunable bipolar response photodetector.The mechanisms underlying photocurrent generation were scrutinized via bias-,power-,and position-dependent mapping photoresponse measurements,identifying the photovoltaic effect,which is attributable to the Schottky junction’s built-in electric field,as the predominant mechanism.The prototype Au-WS2-graphene photodetector exhibits a remarkable light on/off ratio of 1.2×10^(6),a specific detectivity of 6.12×10^(11)cm H^(z1/2)W^(-1)with 20μs response time at 638 nm.The wide gate-tunable responsivity provides an adjustability scope,ranging from 0.9 to 3.1 A W^(-1).Notably,the device demonstrates an exceptional linear photocurrent response,with a linear dynamic range(LDR)value approximating 130 dB,which significantly surpasses that of other photodetectors based on TMDs.

关键词： WS2/graphene van der Waals heterojunction gate-tunable bipolar response

Accelerated generation of holograms with ultra-low memory symmetrically high-compressed look-up table

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Chinese physics B 2024年第4期33卷 466-471页

作者：杨燕朱建英孙敏远毕勇 Applied Laser Research Center Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.

关键词： computergenerated hologram look-up table holography