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International Journal of Minerals,metallurgy and Materials 2024年第5期31卷 877-886页

作者： Qiuhong Liu Qing Du Xiaobin Zhang Yuan Wu Andrey A.Rempel Xiangyang Peng Xiongjun Liu Hui Wang Wenli Song Zhaoping Lü Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China institute of metallurgy of the ural Branch of the russian academy of sciences Ekaterinburg 620016Russia China Nuclear Power Technology Research institute Co.Ltd. Shenzhen 518000China institute of High Energy physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China

Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied *** electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex *** this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of *** using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was ***,the perspective related to application of TEM techniques in HEAs are also discussed.

关键词： high entropy alloys transmission electron microscopy short-range ordering deformation mechanisms

Pulsed THz radiation under ultrafast optical discharge of vacuum photodiode

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Frontiers of Optoelectronics 2024年第2期 100-113页

作者： Aleksandr A.Ushakov Kseniia A.Mamaeva Leonid V.Seleznev Georgy E.Rizaev Vladimir Bukin Timophey V.Dolmatov Pavel A.Chizhov Vladimir Bagdasarov Sergey V.Garnov Prokhorov General physics institute of the russian academy of sciences Physical institute Russian Academy of Sciences Moscow institute of physics and Technology russian institute for Scientific and Technical Information

In this paper, we first present an experimental demonstration of terahertz radiation pulse generation with energy up to 5 pJ under the electron emission during ultrafast optical discharge of a vacuum photodiode. We use a femtosecond optical excitation of metallic copper photocathode for the generation of ultrashort electron bunch and up to 45 kV/cm external electric field for the photo-emitted electron acceleration. Measurements of terahertz pulses energy as a function of emitted charge density, incidence angle of optical radiation and applied electric field have been provided. Spectral and polarization characteristics of generated terahertz pulses have also been studied. The proposed semi-analytical model and simulations in COMSOL Multiphysics prove the experimental data and allow for the optimization of experimental conditions aimed at flexible control of radiation parameters.

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Terahertz high-sensitivity SIS mixer based on Nb–AlN–NbN hybrid superconducting tunnel junctions

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Chinese physics B 2024年第5期33卷 681-686页

作者：刘博梁刘冬姚明金骏达王争李婧史生才 Artem Chekushkin Michael Fominsky Lyudmila Filippenko Valery Koshelets Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space sciences University of Science and Technology of ChinaHefei 230026China Kotel'nikov institute of Radio Engineering and Electronics Russian Academy of SciencesMoscow 125009Russia

The terahertz band,a unique segment of the electromagnetic spectrum,is crucial for observing the cold,dark universe and plays a pivotal role in cutting-edge scientific research,including the study of cosmic environments that support life and imaging black ***-sensitivity superconductor–insulator–superconductor(SIS)mixers are essential detectors for terahertz astronomical telescopes and interferometric *** to the commonly used classical Nb/AlO_(x)/Nb superconducting tunnel junction,the Nb/AlN/NbN hybrid superconducting tunnel junction has a higher energy gap voltage and can achieve a higher critical current *** makes it particularly promising for the development of ultra-wideband,high-sensitivity coherent detectors or mixers in various scientific research *** this paper,we present a superconducting SIS mixer based on Nb/AlN/NbN parallel-connected twin junctions(PCTJ),which has a bandwidth extending up to490 GHz–720 *** best achieved double-sideband(DSB)noise temperature(sensitivity)is below three times the quantum noise level.

关键词： SIS mixer terahertz gap voltage critical current density hybrid superconducting tunnel junction

Constraints on holographic QCD phase transitions from PTA observations

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Science China(physics,Mechanics & Astronomy) 2024年

作者： Song He Li Li Sai Wang Shao-Jiang Wang Center for Theoretical physics and College of physics Jilin University School of Physical Science and Technology Ningbo University Max Planck institute for Gravitational physics (Albert Einstein institute) CAS Key Laboratory of Theoretical physics Institute of Theoretical Physics Chinese Academy of Sciences School of Fundamental physics and Mathematical sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences (UCAS) School of Physical sciences University of Chinese Academy of Sciences (UCAS) Theoretical physics division Institute of High Energy Physics Chinese Academy of Sciences

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves(GWs) within the standard model of particle physics. If these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

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Compression of Battery X-Ray Tomography Data with Machine Learning

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Chinese physics Letters 2024年第9期41卷 153-158页

作者： Zipei Yan Qiyu Wang Xiqian Yu Jizhou Li Michael K.-P.Ng Department of Electronic Engineering The Chinese University of Hong KongHong KongChina Beijing National Laboratory for Condensed Matter physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China Huairou division Institute of PhysicsChinese Academy of SciencesBeijing 101400China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China CUHK Shenzhen Research institute Shenzhen 518057China Department of Mathematics Hong Kong Baptist UniversityHong KongChina

With the increasing demand for high-resolution x-ray tomography in battery characterization,the challenges of storing,transmitting,and analyzing substantial imaging data necessitate more efficient *** data compression methods struggle to balance reduction ratio and image quality,often failing to preserve critical details for accurate *** study proposes a machine learning-assisted compression method tailored for battery x-ray imaging *** physics-informed representation learning,our approach significantly reduces file sizes without sacrificing meaningful *** validate the method on typical battery materials and different x-ray imaging techniques,demonstrating its effectiveness in preserving structural and chemical *** results show an up-to-95 compression ratio while maintaining high fidelity in the projection and reconstructed *** proposed framework provides a promising solution for managing large-scale battery x-ray imaging datasets,facilitating significant advancements in battery research and development.

关键词： battery Battery details

Utilizing a metal-forging inspired chain combing strategy to enhance properties and expand applications of Nylon 66 plastic via heat inducing

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Nano Research 2024年第3期17卷 2164-2171页

作者： Junyu Yang Jiangwei Zhang Nan Wang Guangyuan Zhou division of Energy Materials Daglian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Innovation Center of Energy Material and Chemistry College of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot 010021China

The mechanical properties of engineering plastics can be enhanced through effective surface mechanical treatment(SMT),which can be applied to various types of engineering plastics,eliminating the limitations of conventional polymer processing and could potentially extend their applications and improve their performance and reliability as structural-functional *** by metal forging,this work proposes a simple and effective SMT strategy to enhance the mechanical properties of polyamide 66(PA66).Tensile tests have shown that SMTed PA66 samples exhibit significant improvements in both Young’s modulus and ultimate tensile strength(UTS),with a 2104 MPa Young’s modulus,almost double that of the pristine samples,and a 35.56%increase in UTS,reaching 183 ***,the modulus within the localized SMTed surface layer could reach up to 14 GPa,which is approximately 14 times higher than that of the pristine *** Vickers hardness within the localized SMTed surface layer can be doubled,reaching 10.72 Hv,and the crystallinity can increase by approximately 20%compared to the untreated ***,force field molecular dynamics(FFMD)simulations were conducted to investigate the ternary relationship between the SMT method,PA66’s molecular structure,and its *** combination of MD simulations and versatile structural characterizations provides evidence that the SMT method’s mechanism,under heat induction,results in a chain-combing procedure that changes the polymer’s molecular morphology microscopically and enhances its mechanical properties macroscopically.

关键词： Nylon 66 mechanical properties hardness crystallinity structural characterizations molecular dynamics simulation

Measuring the anisotropies in astrophysical and cosmological gravitational-wave backgrounds with Taiji and LISA networks

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Science China(physics,Mechanics & Astronomy) 2024年

作者： Zhi-Chao Zhao Sai Wang Department of Applied physics College of Science China Agricultural University Theoretical physics division Institute of High Energy Physics Chinese Academy of Sciences

We investigate the capabilities of space-based gravitational-wave detector networks, specifically Taiji and LISA, to measure the anisotropies in stochastic gravitational-wave background(SGWB), which are characterized by the angular power spectrum. We find that a detector network can improve the measurement precision of anisotropies by at most fourteen orders of magnitude,depending on the angular multipoles. By doing so, we can enhance our understanding of the physical origins of SGWB, both in astrophysical and cosmological contexts. We assess the prospects of the detector networks for measuring the parameters of angular power spectrum. We further find an inevitable effect of cosmic variance, which can be suppressed by a better angular resolution, strengthening the importance of configuring detector networks. Our findings also suggest a potential detection of the kinematic dipole due to Doppler boosting of SGWB.

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Light People:*** May Lau,newly elected US NAE member in Hong Kong,talks about future of photonics and women in science

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Light(Science & Applications) 2024年第4期13卷 602-608页

作者： Yating Wan Chenzi Guo Electrical and Computer Engineering the ComputerElectrical and Mathematical Sciences and Engineering DivisionKing Abdullah University of Science and Technology23955-6900 ThuwalSaudi Arabia Changchun institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchunChina

Editorial Photonics technology remains a driving force in today’s scientific landscape,marked by continuous innovation and crossdisciplinary *** an enlighting conversation with Light:Science&Applications,*** May Lau,a pioneer in photonics research,shares her deep insights on the evolution of technologies of LEDs,lasers,challenges of hetero-epitaxy,and the future of micro-LEDs and quantum dot *** honored as a member of the US National academy of Engineering(NAE)for her significant contributions to photonics and electronics using III-V semiconductors on silicon,*** stands out as the sole Hong Kong scholar inducted into the NAE this year,joining 114 new and 21 international *** this exclusive Light People interview,*** shares her journey as a pioneering woman in engineering,her commitment to mentorship and academia,and her perspective on advancing female representation in *** summary provided is distilled from ***’s thoughtful responses during the *** a deeper exploration of ***’s experiences and advice,the full interview is available in the Supplementary material.

关键词： interview lighting driving

Impact of doping profiles on the formation of laser-active centers in bismuth-doped GeO_(2)–SiO_(2)glass fibers

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Photonics Research 2024年第2期12卷 260-270页

作者： SERGEY ALYSHEV ALEXANDER VAKHRUSHEV ALEKSANDR KHEGAI ELENA FIRSTOVA KONSTANTIN RIUMKIN MIKHAIL MELKUMOV LYUDMILA ISKHAKOVA ANDREY UMNIKOV SERGEI FIRSTOV Prokhorov General physics institute of the russian academy of sciences Dianov Fiber Optics Research Center119333 MoscowRussia Devyatykh institute of Chemistry of High-Purity Substances of the russian academy of sciences 603951 Nizhny NovgorodRussia

Multi-wavelength-band transmission technology based on the exploitation of the extended spectral region is considered as a potential approach to increase the transmission capacity in the deployed fiber-optic communication *** development of optical amplifiers operating in the O-,E-,S-,and U-telecom bands is an extremely important challenge for the successful implementation of this ***-doped fibers are of increasing interest as gain materials,which can be used to provide broadband amplification in the mentioned telecom *** is due to the ability of Bi ions incorporated into glass network to form bismuth active centers(BACs)with specific optical properties,which are primarily determined by the glass *** this work,the impact of the doping profiles of both Ge atoms as glass modifiers and Bi ions on the BACs formation is studied using a series of bismuth-doped fibers fabricated by the modified chemical vapor deposition(MCVD)*** Bi-to-BACs conversion efficiency in various spatial regions of the studied samples is *** is turned out that for high-Bi concentration regions,the conversion efficiency is very low(less than 10%).In addition,the relationship of the conversion efficiency to the distribution of Bi ions and/or Ge atoms is ***,a continuous-wave laser at 1.46μm with a record slope efficiency of 80%is demonstrated using a Bi-doped fiber with confined doping profile,where the Bi-to-BACs conversion efficiency is 35%.This paper provides new information which might help to facilitate understanding of the features of Bi-doped fibers and their potentially achievable characteristics.

关键词： fiber fibers bismuth

Designing ABC-6 family small pore zeolites by epitaxial growth approach

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Chinese Chemical Letters 2024年第3期35卷 508-512页

作者： Xiaohui Cui Jia Lv Chao Ma Yujiao Wang Zhenghao Jia Daliang Zhang Peng Guo Zhongmin Liu Henan institute of Advanced Technology Zhengzhou UniversityZhengzhou 450001China National Engineering Research Center of Lower-Carbon Catalysis Technology Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Multi-scale Porous Materials Center Institute of Advanced Interdisciplinary Studies&School of Chemistry EngineeringChongqing UniversityChongqing 400044China University of Chinese academy of sciences Beijing 100049China division of Energy Research Resources Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Aluminosilicate small pore zeolites belonging to ABC-6 family play crucially important roles in the high methanol conversion with the high selectivity of light olefins,gas separation and storage,and selective catalytic reduction of NO_(x).In this work,we report a general method,called the epitaxial growth approach,for designing ABC-6 family small pore *** is mainly realized through the epitaxial growth on the nonporous SOD-type zeolite in the presence of inorganic cations(Na^(+)and K^(+))combined with a variety of organic structure directing agents(OSDAs).In this case,a series of ABC-6 family small pore zeolites such as ERI-,SWY-,LEV-,AFX-,and PTT-type zeolites have been successfully synthesized within a few *** importantly,the advanced focused ion beam(FIB)and the low-dose high-resolution transmission electron microscopy(HRTEM)imaging technique have been utilized for unraveling the zeolite heterojunction at the atomic level during the epitaxial growth *** turns out(222)crystallographic planes of the SOD-type zeolite substrate provide unique pre-building units,which facilitate the growth of targeted ABC-6 family small pore zeolites along its ***,the morphologies of ERI-type zeolite can also be tuned through the epitaxial growth approach,achieving a longer lifetime in the methanol conversion.

关键词： Zeolite structure Zeolite synthesis Structural characterizations Low-dose imaging Focused ion beam