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Unveiling the time-temperature dependence of metastability of supercooled liquid using nano-calorimetry

Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 119-127页

作者： Yijun Ding Lijian Song Zheng Wang Ruiqi Yu Junqiang Wang Lina Hu Yuanzheng Yue Edgar D.Zanotto key laboratory for Liquid-Solid Structural Evolution and Processing of Materials(ministry of Education) Shandong University Jinan 250061China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China key laboratory of Experimental Teratology Shandong University Jinan 250061 China Department of Chemistry and Bioscience Aalborg UniversityAalborg 9220Denmark Department of Materials Engineering Federal University of Sao CarlosSao Carlos SP 13.565-905Brazil

There is a lack of understanding of both the conversion of an unstable glass into a metastable supercooled liquid(MSL) upon heating and the metastability of MSLs. In this study, we investigated the time-and temperature-dependent metastability of an MSL using an advanced nano-calorimetric technique. The chosen Au-based metallic glass(Au MG) allowed adequate probing of its MSL in a temperature range between 10 and 70 K above the standard glass transition temperature. We found that the survival time of the MSL state is a quadratic function of temperature. Beyond this duration threshold, the sample undergoes fast crystallization even if it is below the crystallization temperature that is measured using differential scanning *** transmission electron microscopy, we observed the formation of clusters with a partially ordered lattice structure during relaxation in the Au MG sample fabricated using a nano-calorimeter. The atomic ordering within the clusters was enhanced by increasing time and temperature in the MSL region. Once the as-produced glass entered the MSL stage upon heating followed by a quenching stage at a given rate, the mechanical properties of the quenched glass remained the same regardless of its holding temperature and duration within the MSL region. This work provides insights into the glass-MSL-crystal transformation and offers guidance for designing standard metallic glasses for property characterizations.

关键词： metallic glass supercooled liquid relaxation nucleation nano calorimetric technology

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Ionic liquid-trimetallic electrocatalytic system for C–O bond cleavage in lignin model compounds and lignin under ambient conditions

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Nano Research 2024年第4期17卷 2420-2428页

作者： Guangyong Liu Yumiao Lu JunFeng Lu Yanlei Wang Shijing Liang Hongyan He Lilong Jiang National Engineering Research Center of Chemical Fertilizer Catalyst Fuzhou UniversityFuzhou 350002China CAS key laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex SystemsBeijing Key Laboratory of Ionic Liquids Clean ProcessInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Longzihu New Energy laboratory Zhengzhou Institute of Emerging Industrial TechnologyZhengzhou 450000China

Electrocatalytic depolymerization of lignin into value-added chemicals offers a promising technique to make biorefining ***,we report a robust trimetallic PdNiBi electrocatalyst for reductive C–O bond cleavage of different lignin model dimers and oxidized lignin under mild *** reduction reaction proceeds with complete substrate conversion and excellent yields toward monomers of phenols(80%–99%)and acetophenones(75%–96%)in the presence of an ionic liquid electrolyte with operational *** experimental investigations together with density functional theory(DFT)calculations reveal that the outstanding performance of the catalyst results from the synergistic effect of the metal elements,which facilitates the easier formation of a key Cαradical intermediate and the facile desorption of the as-formed products at the *** results open up new opportunities for lignin valorization through the green electrocatalytic approach.

关键词： electrocatalytic depolymerization lignin Ionic liquids density functional theory(DFT)calculation

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(DarkAI)Mapping the large-scale density field of dark matter using artificial intelligence

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 143-159页

作者： Zitong Wang Feng Shi Xiaohu Yang Qingyang Li Yanming Liu Xiaoping Li School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Department of Astronomy School of Physics and Astronomyand Shanghai Key Laboratory for Particle Physics and CosmologyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute and key laboratory for Particle Physics Astrophysics and CosmologyMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China Institute for Astronomy University of EdinburghRoyal ObservatoryEdinburgh EH93HJUnited Kingdom

Herein,we present a deep-learning technique for reconstructing the dark-matter density field from the redshift-space distribution of dark-matter *** built a UNet-architecture neural network and trained it using the COmoving Lagrangian Acceleration fast simulation,which is an approximation of the N-body simulation with 5123 particles in a box size of 500 h^(-1)***,we tested the resulting UNet model not only with training-like test samples but also with standard N-body simulations,such as the Jiutian simulation with 61443particles in a box size of 1000 h^(-1)Mpc and the ELUCID simulation,which has a different *** real-space dark-matter density fields in the three simulations can be reconstructed reliably with only a small reduction of the cross-correlation power spectrum at 1%and 10%levels at k=0.1 and 0.3 h Mpc-1,*** reconstruction clearly helps to correct for redshift-space distortions and is unaffected by the different cosmologies between the training(Planck2018)and test samples(WMAP5).Furthermore,we tested the application of the UNet-reconstructed density field to obtain the velocity&tidal field and found that this approach provides better results compared with the traditional approach based on the linear bias model,showing a 12.2%improvement in the correlation slope and a 21.1%reduction in the scatter between the predicted and true ***,our method is highly efficient and has excellent extrapolation reliability beyond the training *** provides an ideal solution for determining the three-dimensional underlying density field from the plentiful galaxy survey data.

关键词： dark matter large-scale structure cosmology

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Review on laser directed energy deposited aluminum alloys

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International Journal of Extreme Manufacturing 2024年第2期6卷 84-131页

作者： Tian-Shu Liu Peng Chen Feng Qiu Hong-Yu Yang Nicholas Tan Yew Jin Youxiang Chew Di Wang Ruidi Li Qi-Chuan Jiang Chaolin Tan Singapore Institute of Manufacturing Technology(SIMTech) Agency for ScienceTechnology and Research(A∗STAR)5 Cleantech LoopSingapore 636732Singapore State key laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025People’s Republic of China key laboratory of Automobile Materials Ministry of Education and Department of Materials Science and EngineeringJilin UniversityChangchun 130025People’s Republic of China School of Mechanical&Automotive Engineering South China University of TechnologyGuangzhou 510640People’s Republic of China State key laboratory of Powder Metallurgy Central South UniversityChangsha 410083People’s Republic of China

Lightweight aluminum(Al)alloys have been widely used in frontier fields like aerospace and automotive industries,which attracts great interest in additive manufacturing(AM)to process high-value Al *** a mainstream AM technique,laser-directed energy deposition(LDED)shows good scalability to meet the requirements for large-format component manufacturing and ***,LDED Al alloys are highly challenging due to their inherent poor printability(*** laser absorption,high oxidation sensitivity and cracking tendency).To further promote the development of LDED high-performance Al alloys,this review offers a deep understanding of the challenges and strategies to improve printability in LDED Al *** porosity,cracking,distortion,inclusions,element evaporation and resultant inferior mechanical properties(worse than laser powder bed fusion)are the key challenges in LDED Al *** parameter optimizations,in-situ alloy design,reinforcing particle addition and field assistance are the efficient approaches to improving the printability and performance of LDED Al *** underlying correlations between processes,alloy innovation,characteristic microstructures,and achievable performances in LDED Al alloys are *** benchmark mechanical properties and primary strengthening mechanism of LDED Al alloys are *** review aims to provide a critical and in-depth evaluation of current progress in LDED Al *** opportunities and perspectives in LDED high-performance Al alloys are also outlined.

关键词： additive manufacturing laser directed energy deposition(LDED) aluminum alloys printability aluminum matrix composite auxiliary fields mechanical properties

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New steelmaking process based on clean deoxidation technology

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1249-1262页

作者： Zhongliang Wang Yanping Bao State key laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

After the converter steelmaking process,a considerable number of ferroalloys are needed to remove dissolved oxygen from the molten steel,but it also forms a lot of oxide inclusions that cannot be completely *** the same time,it increases the carbon emis-sions in the steel production *** years of research,our team have developed a series of clean deoxidation technologies,includ-ing carbon deoxidation,hydrogen deoxidation,and waste plastic deoxidation of molten steel to address the aforementioned *** this study,thermodynamic calculations and laboratory experiments were employed to verify that carbon and hydrogen can reduce the total oxygen content in the molten steel melt to below 5×10^(-6) and 10×10^(-6),*** analysis of the deoxidation mechanisms and ef-fects of polyethylene and polypropylene was also *** addition,the applications of carbon deoxidation technology in different steels with the hot-state experiment and industrial production were discussed *** carbon deoxidation experimental results of different steels were as follows:(1)the oxygen content of bearing steel was effectively controlled at 6.3×10^(-6) and the inclusion number density was lowered by 74.73%compared to aluminum deoxidized bearing steel;(2)the oxygen content in gear steel was reduced to 7.7×10^(-6) and a 54.49%reduction of inclusion number density was achieved with almost no inclusions larger than 5μm from the average level of industry gear steels;(3)a total oxygen content of M2 high-speed steel was as low as 3.7×10^(-6).In industrial production practice,car-bon deoxidation technique was applied in the final deoxidation stage for non-aluminum deoxidized bearing steel,and it yielded excellent results that the oxygen content was reduced to below 8×10^(-6) and the oxide inclusions in the steel mainly consist of silicates,along with small amounts of spinel and calcium aluminate.

关键词： clean deoxidation carbon deoxidation hydrogen deoxidation waste plastics deoxidation

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Co-Sharing Waveform Design for Millimeter-Wave Radar Communication Systems

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China Communications 2024年第6期21卷 305-318页

作者： Cui Gaofeng He Mengmin Xu Lexi Wang Changheng Wang Weidong School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China key laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China China United Network Communications Corporation Beijing 100048China

Millimeter-wave(mmWave)radar communication has emerged as an important technique for future wireless ***,the interference between the radar signal and communication data is the main issue that should be considered for the joint radar communication *** this paper,a co-sharing waveform(CSW)is proposed to achieve communication and radar sensing *** eliminate the co-interference between the communication and sensing signal,signal splitting and processing methods for communication data demodulation and radar signal processing are given *** results show that the bit error rate(BER)of CSW is close to that of the pure communication ***,the proposed CSW can achieve better performance than the existing waveforms in terms of range and velocity estimation.

关键词： co-sharing waveform millimeter-wave radar communication radar sensing range and velocity estimation

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Advancing Energy Systems with In-Situ and Operando Surface-Enhanced Raman Scattering Spectroscopy

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CCS Chemistry 2024年第6期6卷 1403-1421页

作者： Haoming Bao Shi Xuan Leong Jaslyn Ru Ting Chen Zhenhai Shi Suli Chen Yan Lv Tianxi Liu In Yee Phang Xing Yi Ling key laboratory of Synthetic and Biological Colloids Ministry of EducationInternational Joint Research Laboratory for Nano Energy CompositesSchool of Chemical and Material EngineeringJiangnan UniversityWuxi 214122 School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological UniversitySingapore 637371

Surface-enhanced Raman scattering spectroscopy(SERS)has emerged as a powerful analytical technique to enable nanoscale investigations of energy *** mini-review focuses on the applications of in-situ and operando SERS in energy-related research,highlighting its unique capabilities and significant contributions to understanding energy storage and conversion *** first introduce the fundamental principles of SERS,key SERS-derived techniques,and commonly employed ***,we delve into the diverse applications of in-situ and operando SERS across various energy systems,encompassing photocatalytic and electrocatalytic systems,fuel cells,solar cells,and ***,we conclude with our perspective on the current challenges and prospects in this *** hope thismini-review serves as an essential overview to guide the design and implementation of in-situ and operando SERS studies of energy systems.

关键词： surface-enhanced Raman scattering spectroscopy in-situ operando energy systems photocatalysis electrocatalysis fuel cells solar cells batteries

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Quantum dot-enabled infrared hyperspectral imaging with single-pixel detection

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Light(Science & Applications) 2024年第6期13卷 1112-1121页

作者： Heyan Meng Yuan Gao Xuhong Wang Xianye Li Lili Wang Xian Zhao Baoqing Sun School of Information Sciences and Engineering Shandong UniversityQingdaoChina Center for Optics Research and Engineering(CORE) Key Laboratory of Laser&Infrared System(Shandong University)Ministry of EducationShandong UniversityQingdaoChina School of Mechanical Electrical and Information EngineeringShandong UniversityWeihaiChina

Near-infrared(NIR)hyperspectral imaging is a powerful technique that enables the capture of three-dimensional(3D)spectra-spatial information within the NIR spectral range,offering a wide array of ***,the high cost associated with InGaAs focal plane array(FPA)has impeded the widespread adoption of NIR hyperspectral *** this challenge,in this study,we adopt an alternative approach—single-pixel detection for NIR hyperspectral *** investigation reveals that single-pixel detection outperforms conventional FPA,delivering a superior signal-to-noise ratio(SNR)for both spectral and imaging *** implement this strategy,we leverage self-assembled colloidal quantum dots(CQDs)and a digital micromirror device(DMD)for NIR spectral and spatial information multiplexing,complemented by single-pixel detection for simultaneous spectral and image *** experimental results demonstrate successful NIR hyperspectral imaging with a detection window about 600 nm and an average spectral resolution of 8.6 nm with a pixel resolution of 128×*** resulting spectral and spatial data align well with reference instruments,which validates the effectiveness of our *** circumventing the need for expensive and bulky FPA and wavelength selection components,our solution shows promise in advancing affordable and accessible NIR hyperspectral imaging technologies,thereby expanding the range of potential applications.

关键词： spectral Quantum mirror

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Indentation behavior of a semi-infinite piezoelectric semiconductor under a rigid flat-ended cylindrical indenter

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 649-662页

作者： Shijing GAO Lele ZHANG Jinxi LIU Guoquan NIE Weiqiu CHEN State key laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei key laboratory for Mechanics of Intelligent Materials and Structures Department of Engineering MechanicsShijiazhuang Tiedao UniversityShijiazhuang 050043China State key laboratory of Computer Aided Design and Computer Graphics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

This paper theoretically studies the axisymmetric frictionless indentation of a transversely isotropic piezoelectric semiconductor(PSC)half-space subject to a rigid flatended cylindrical *** contact area and other surface of the PSC half-space are assumed to be electrically *** the Hankel integral transformation,the problem is reduced to the Fredholm integral equation of the second *** equation is solved numerically to obtain the indentation behaviors of the PSC half-space,mainly including the indentation force-depth relation and the electric potential-depth *** results show that the effect of the semiconductor property on the indentation responses is limited within a certain range of variation of the steady carrier *** dependence of indentation behavior on material properties is also analyzed by two different kinds of *** element simulations are conducted to verify the results calculated by the integral equation technique,and good agreement is demonstrated.

关键词： piezoelectric semiconductor(PSC) insulating indenter electromechanical response singular integral equation finite element simulation

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A cost-efficient quantum access network with qubit-based synchronization

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 12-22页

作者： Chunfeng Huang Ye Chen Tingting Luo Wenjie He Xin Liu Zhenrong Zhang Kejin Wei Guangxi key laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Guangxi key laboratory of Multimedia Communications and Network Technology School of Computer Electronics and InformationGuangxi UniversityNanning 530004China

Quantum key distribution(QKD)is a physical layer encryption technique that enables two distant parties to exchange secure keys with information-theoretic *** the last two decades,QKD has transitioned from laboratory research to real-world applications,including multi-user quantum access networks(QANs).This network structure allows users to share a single-photon detector at a network node through time-division multiplexing,thereby significantly reducing the network ***,current QAN implementations require additional hardware for auxiliary tasks such as time *** address this issue,we propose a cost-efficient QAN that uses qubit-based *** this approach,the transmitted qubits facilitate time synchronization,eliminating the need for additional synchronization *** tested our scheme by implementing a network for two users and successfully achieved average secure key rates of 53.84 kbps and 71.90 kbps for each user over a 50-km commercial fiber *** addition,we investigated the capacity of the access network under cross-talk and loss *** simulation results demonstrate that this scheme can support a QAN with 64 users with key rates up to 1070 *** work provides a feasible and cost-effective way to implement a multi-user QKD network,further promoting the widespread application of QKD.

关键词： quantum key distribution quantum access network qubit-based synchronization

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