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Photoionisation detection of a single Er3+ ion with sub-100-ns time resolution

National Science Review 2024年第4期11卷 38-45页

作者： Yangbo Zhang Wenda Fan Jiliang Yang Hao Guan Qi Zhang Xi Qin Changkui Duan Gabriele G.de Boo Brett C.Johnson Jeffrey C.Mc Callum Matthew J.Sellars Sven Rogge Chunming Yin Jiangfeng Du CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical sciences University of Science and Technology of China CAS Center for excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China centre of excellence for Quantum Computation and Communication Technology School of Physics University of New South Wales centre of excellence for Quantum Computation and Communication Technology School of Engineering RMIT University centre of excellence for Quantum Computation and Communication Technology School of Physics University of Melbourne centre of excellence for Quantum Computation and Communication Technology Research School of Physics and Engineering Australian National University

Efficient detection of single optical centres in solids is essential for quantum information processing, sensing and single-photon generation *** this work,we use radio-frequency（RF） reflectometry to electrically detect the photoionisation induced by a single Er3+ion in *** high bandwidth and sensitivity of the RF reflectometry provide sub-100-ns time resolution for the photoionisation *** this technique,the optically excited state lifetime of a single Er3+ion in a Si nano-transistor is measured for the first time to be 0.49±0.04μ*** results demonstrate an efficient approach for detecting a charge state change induced by Er excitation and *** approach could be used for fast readout of other single optical centres in solids and is attractive for large-scale integrated optical quantum systems thanks to the multi-channel RF reflectometry demonstrated with frequency multiplexing techniques.

关键词： single optical centres erbium ions RF reflectometry photoionisation detection

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A versatile model with three-dimensional triangular lattice for unconventional transport and various topological effects

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National Science Review 2024年第1期11卷 204-214页

作者： Jing-Yang You Gang Su Yuan Ping Feng Department of Physics National University of Singapore Kavli Institute for Theoretical sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences centre for Advanced 2D Materials National University of Singapore

The finite Berry curvature in topological materials can induce many subtle phenomena, such as the anomalous Hall effect(AHE), spin Hall effect(SHE), anomalous Nernst effect(ANE), non-linear Hall effect(NLHE) and bulk photovoltaic effects. To explore these novel physics as well as their connection and coupling, a precise and effective model should be developed. Here, we propose such a versatile model—a 3D triangular lattice with alternating hopping parameters, which can yield various topological phases,including kagome bands, triply degenerate fermions, double Weyl semimetals and so on. We reveal that this special lattice can present unconventional transport due to its unique topological surface states and the aforementioned topological phenomena, such as AHE, ANE, NLHE and the topological photocurrent effect. In addition, we also provide a number of material candidates that have been synthesized experimentally with this lattice, and discuss two materials, including a non-magnetic triangular system for SHE, NLHE and the shift current, and a ferromagnetic triangular lattice for AHE and ANE. Our work provides an excellent platform, including both the model and materials, for the study of Berry-curvature-related physics.

关键词： three-dimensional triangular lattice different topological phases various topological effects Berry curvature

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Deep Learning Based Efficient Crowd Counting System

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Computers, Materials & Continua 2024年第6期79卷 4001-4020页

作者： Waleed Khalid Al-Ghanem Emad Ul Haq Qazi Muhammad Hamza Faheem Syed Shah Amanullah Quadri Department of Computer Engineering College of Computer and Information SciencesKing Saud UniversityRiyadh12372Saudi Arabia centre of excellence in Cybercrime and Digital Forensics Naif Arab University for Security SciencesRiyadh14812Saudi Arabia Center of excellence for Information Assurance(COEIA) King Saud UniversityRiyadh12372Saudi Arabia

Estimation of crowd count is becoming crucial nowadays,as it can help in security surveillance,crowd monitoring,and management for different *** is challenging to determine the approximate crowd size from an image of the crowd’s *** in this research study,we proposed a multi-headed convolutional neural network architecture-based model for crowd counting,where we divided our proposed model into two main components:(i)the convolutional neural network,which extracts the feature across the whole image that is given to it as an input,and(ii)the multi-headed layers,which make it easier to evaluate density maps to estimate the number of people in the input image and determine their number in the *** employed the available public benchmark crowd-counting datasets UCF CC 50 and ShanghaiTech parts A and B for model training and testing to validate the model’s *** analyze the results,we used two metrics Mean Absolute Error(MAE)and Mean Square Error(MSE),and compared the results of the proposed systems with the state-of-art models of crowd *** results show the superiority of the proposed system.

关键词： Crowd counting EfficientNet multi-head attention convolutional neural network transfer learning

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Two-stage aging treatment to accelerate aging kinetics without impairing strength in B4C/7A04Al composite

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Science China Technological sciences 2024年第8期67卷 2485-2492页

作者： CHEN YunTao MA GuoNan ZHU ShiZe WANG Dong XIAO BoLv MA ZongYi Shi-Changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China centre of excellence for Advanced Materials

Aging treatments are the key process to obtain satisfactory strength for 7xxxAl alloys and their composites. However, traditional single-stage（SS） aging is time-consuming to reach a peak strength condition. In this study, an efficient 120℃ + 160℃ two-stage（TS） aging treatment was proposed on a B4C/7A04Al composite fabricated via powder metallurgy（PM） technology, which could acquire similar peak-aging strength but only took about 15% of the time compared to traditional 120℃ SS aging. The evolution of precipitation during the TS aging was investigated, as well as those of the 7A04Al alloys for comparison. In the second stage aging process, the higher aging temperature accelerated the nucleation of η′ phases inside the grains and thus increased the density of precipitates. Moreover, the short aging time limited the coarsening of precipitates and the broadening of precipitatefree zones. The above factors were beneficial for quickly obtaining satisfactory precipitation strengthening effects. The B4C/7A04Al composite exhibited slower aging kinetics than the 7A04Al alloy in the TS aging. Mg elements consumption by the chemical reaction between B impurities introduced by B4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B4C/7A04Al composite. Nevertheless, the precipitation sequence was not affected.

关键词： aluminum matrix composites aging treatment powder metallurgy mechanical properties precipitation

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Effect of heat treatment on the microstructure, mechanical properties and fracture behaviors of ultra-high-strength SiC/Al–Zn–Mg–Cu composites

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2233-2243页

作者： Guonan Ma Shize Zhu Dong Wang Peng Xue Bolü Xiao Zongyi Ma Shi-changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences centre of excellence for Advanced Materials

A high-zinc composite, 12vol% SiC/Al–13.3 Zn–3.27 Mg–1.07Cu(wt%), with an ultra-high-strength of 781 MPa was successfully fabricated through a powder metallurgy method, followed by an extrusion process. The effects of solid-solution and aging heat treatments on the microstructure and mechanical properties of the composite were extensively investigated. Compared with a single-stage solid-solution treatment, a two-stage solid-solution treatment(470°C/1 h + 480°C/1 h) exhibited a more effective solid-solution strengthening owing to the higher degree of solid-solution and a more uniform microstructure. According to the aging hardness curves of the composite, the optimized aging parameter(100°C/22 h) was determined. Reducing the aging temperature and time resulted in finer and more uniform nanoscale precipitates but only yielded a marginal increase in tensile strength. The fractography analysis revealed that intergranular cracking and interface debonding were the main fracture mechanisms in the ultra-high-strength SiC/Al–Zn–Mg–Cu composites. Weak regions, such as the SiC/Al interface containing numerous compounds and the precipitate-free zones at the high-angle grain boundaries,were identified as significant factors limiting the strength enhancement of the composite. Interfacial compounds, including MgO, MgZn2,and Cu5Zn8, reduced the interfacial bonding strength, leading to interfacial debonding.

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Confinement effect on CO_(2)and CH_(4)permeability in shale

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Energy Geoscience 2024年第1期5卷 256-263页

作者： Vikram Vishal Tuli Bakshi Computational and Experimental Geomechanics Laboratory Department of Earth SciencesIndian Institute of Technology BombayMumbai400076India National centre of excellence in Carbon Capture and Utilization Indian Institute of Technology BombayMumbai400076India

Gas flow in shales follows a number of physical mechanisms that include Knudsen diffusion,Darcy flow,and adsorption in the matrix and micro *** aim of the study is to resolve the interplay of gas transport in these media at increased effective stress as well as net pore *** this research,we investigated the nature of gas transport in the matrix of shale by sending He,CH_(4)and CO_(2)gases through a transient upstream pressure pulse decay instrument.A series of experiments were conducted at constant pore pressures and a gradually increasing confining *** same study was done in three different scenarios,injecting He,CO_(2)and CH_(4).At a constant pore pressure,gas permeability appears to decrease with an increasing confining pressure and effective *** increasing effective stress,the slip factor also decreases along with the *** decrease in slip could be attributed to prestressing,that is likely to create new *** the three purged gases,permeability of shale to CH_(4)is the highest,and that to CO_(2)is the lowest owing to its high *** permeability of CH_(4)against He,could be attributed to the dual transport mechanism.

关键词： Energy Porous media Gas transport Effective stress

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Interwoven grain boundary makes homoporous and crystalline polymer membrane with high mechanical stability

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Science China Chemistry 2024年

作者： Lianshan Li Zhiyong Tang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in Nanoscience National Centre for Nanoscience and Technology University of Chinese Academy of sciences

Membrane separation is widely used in industry to recover and capture gases or to purify liquids. Compared with conventional separation methods, such as cryogenic and adsorptive or absorptive separation, membrane separation is an energy-efficient and environment-friendly technique that occupies less space and can be operated in a continuous mode [1].

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Two diversities meet in the rhizosphere:root specialized metabolites and microbiome

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Journal of Genetics and Genomics 2024年第5期51卷 467-478页

作者： Xiaochen Wang Jingying Zhang Xinjun Lu Yang Bai Guodong Wang State Key Laboratory of Plant Genomics Institute of Genetics and Developmental BiologyThe Innovative Academy of Seed DesignChinese Academy of SciencesBeijing 100101China CAS-JIC centre of excellence for Plant and Microbial Science Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Hainan Yazhou Bay Seed Laboratory SanyaHainan 572025China College of Advanced Agricultural sciences Chinese Academy of SciencesBeijing 100049China

Plants serve as rich repositories of diverse chemical compounds collectively referred to as specialized *** compounds are of importance for adaptive processes,including interactions with various microbes both beneficial and *** microbes as bioreactors,the chemical diversity undergoes dynamic changes when root-derived specialized metabolites(RSMs)and microbes encounter each other in the *** advancements in sequencing techniques and molecular biology tools have not only accelerated the elucidation of biosynthetic pathways of RSMs but also unveiled the significance of RSMs in plant-microbe *** this review,we provide a comprehensive description of the effects of RSMs on microbe assembly in the rhizosphere and the influence of corresponding microbial changes on plant health,incorporating the most up-to-date information ***,we highlight open questions that remain for a deeper understanding of and harnessing the potential of RSM-microbe interactions to enhance plant adaptation to the ***,we propose a pipeline for investigating the intricate associations between root exometabolites and the rhizomicrobiome.

关键词： Root specialized metabolites Microbiome Plant-microbe interactions Rhizosphere Diversity

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Computational and dark-field ghost imaging with ultraviolet light

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Photonics Research 2024年第2期12卷 226-234页

作者： JIAQI SONG BAOLEI LIU YAO WANG CHAOHAO CHEN XUCHEN SHAN XIAOLAN ZHONG LING-AN WU FAN WANG School of Physics Beihang UniversityBeijing 102206China Australian Research Council centre of excellence for Transformative Meta-Optical Systems Department of Electronic Materials EngineeringResearch School of PhysicsThe Australian National UniversityCanberraACT 2600Australia Institute of Physics Chinese Academy of SciencesBeijing 100190China

Ultraviolet(UV)imaging enables a diverse array of applications,such as material composition analysis,biological fluorescence imaging,and detecting defects in semiconductor ***,scientific-grade UV cameras with high quantum efficiency are expensive and include complex thermoelectric cooling ***,we demonstrate a UV computational ghost imaging(UV-CGI)method to provide a cost-effective UV imaging and detection *** applying spatial–temporal illumination patterns and using a 325 nm laser source,a singlepixel detector is enough to reconstruct the images of *** use UV-CGI to distinguish four UV-sensitive sunscreen areas with different densities on a ***,we demonstrate dark-field UV-CGI in both transmission and reflection *** only collecting the scattered light from objects,we can detect the edges of pure phase objects and small scratches on a compact *** results showcase a feasible low-cost solution for nondestructive UV imaging and *** combining it with other imaging techniques,such as hyperspectral imaging or time-resolved imaging,a compact and versatile UV computational imaging platform may be realized for future applications.

关键词： ghost illumination versatile

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Copper(Ⅰ)-catalyzed diastereodivergent construction of vicinal P-chiral and C-chiral centers facilitated by dual“soft-soft”interaction

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Chinese Chemical Letters 2024年第7期35卷 264-270页

作者： Yan-Bo Li Yi Li Liang Yin CAS Key Laboratory of Synthetic Chemistry of Natural Substances Centre for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032China

A copper(Ⅰ)-catalyzed diastereodivergent addition of phosphinothioates(HP(S)ROR')toα,β-unsaturated thioamides is disclosed,which constructs vicinal P-chiral and C-chiral centers in generally high diastereoand *** this reaction,the kinetic resolution of HP(S)ROR'occurs,which affords(R)-HP(S)Ph OMe in high enantioselectivity in the addition with(R,R)-Ph-BPE as the *** is found through control experiment that dual“soft-soft”interaction,indicated by both1H and31P NMR experiments,is indispensable in the present *** first“soft-soft”interaction between copper(Ⅰ)catalyst and HP(S)ROR'enables facile deprotonation to generate nucleophilic[Cu]-SPROR'*** second one between the[Cu]-SPROR'species andα,β-unsaturated thioamides facilitated the nucleophilic ***,both Michael adducts and(R)-HP(S)PhOMe are easily converted to synthetically useful compounds.

关键词： Copper catalysis Asymmetric catalysis Diastereodivergent synthesis P-Chirality "Soft-soft"interaction

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