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Two-stage aging treatment to accelerate aging kinetics without impairing strength in B_4C/7A04Al composite

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 ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Centre of Excellence for Advanced materials Dongguan 523808China

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 B_4C/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 B_4C/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 B_4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B_4C/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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mRNA vaccine technology for infectious diseases and beyond

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Science China Life Sciences 2024年第10期67卷 2267-2270页

作者： Pei Hao xiao Li Xuan Li Wu zhong Key Laboratory of Molecular Virology and Immunology Shanghai Institute of Immunity and InfectionChinese Academy of Sciences University of Chinese Academy of Sciences Changchun Veterinary Research Institute Chinese Academy of Agricultural Sciences Key Laboratory of Synthetic Biology CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and EcologyChinese Academy of Sciences National Engineering Research Center for the Emergency Drug Beijing Institute of Pharmacology and Toxicology

The rise of mRNA vaccine technology Vaccines stand as one of the most significant medical advancements, playing a crucial role in the prevention of infectious diseases and the improvement of global health. The triumph of smallpox vaccination stands as a towering achievement in the annals of healthcare, leading to the complete elimination of a oncedevastating disease and showcasing the efficacy of vaccination methods.

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Micro/nanosystems for controllable drug delivery to the brain

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The Innovation 2024年第1期5卷 139-157页

作者： Mingzhen Tian Zhichao ma Guang-zhong Yang Institute of Medical Robotics School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Drug delivery to the brain is crucial in the treatment for central nervous system *** significant progress has been made in recent years,there are still major challenges in achieving controllable drug delivery to the *** clinical needs arise from various factors,including controlled drug transport,handling large drug doses,methods for crossing biological barriers,the use of imaging guidance,and effective models for analyzing drug *** advances in micro/nanosystems have shown promise in addressing some of these *** include the utilization of microfluidic platforms to test and validate the drug delivery process in a controlled and biomimetic setting,the development of novel micro/nanocarriers for large drug loads across the blood-brain barrier,and the implementation of micro-intervention systems for delivering drugs through intraparenchymal or peripheral *** this article,we present a review of the latest developments in micro/nanosystems for controllable drug delivery to the *** also delve into the relevant diseases,biological barriers,and conventional *** addition,we discuss future prospects and the development of emerging robotic micro/nanosystems equipped with directed transportation,real-time image guidance,and closed-loop control.

关键词： equipped doses barriers

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Sodium intake:a double-edged sword wielded by the brain

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Science China(Life Sciences) 2024年第7期67卷 1545-1547页

作者： Lingyu Xu xiaolong ma Yi Wang zhong Chen Key Laboratory of Neuropharmacology and Pharmaceutical Sciences Zheiiang Chinese Medical UniversityHangzhou 310053China Institute of Pharmacology&Toxicology College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China

Taste receptors on the tongue discriminate between five fundamental tastes:sour,sweet,bitter,salty,and umami(Chandrashekar et al.,2006).Typically,stimuli that evoke bitterness and acidity prompt aversive responses by animals,whereas sweet and umami flavors are appetitive and *** is unique in that it transitions from an appetitive to an aversive stimulus with increasing concentrations.

关键词： prompt sweet sword

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A novel DPSS filter optimization scheme to reduce the intrinsic interference of FBMC-QAM systems

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High Technology Letters 2024年第1期30卷 68-74页

作者：董琪阳 ma Tianming JIN Jie WU zhong School of Electrical and Electronic Engineering Shanghai University of Engineering ScienceShanghai 201620P.R.China

In order to reduce the intrinsic interference of the filter bank multicarrier-quadrature amplitude modulation(FBMC-QAM)system,a novel filter optimization scheme based on discrete prolate spheroidal sequences(DPSS)is ***,a prototype filter function based on DPSS is designed,since the eigenvalue can be used as an indicator of the energy concentration of DPSS,so a threshold is set,and the sequence with the most concentrated energy is selected under the threshold,that is,the sequence with the eigenvalue higher than the threshold,and the prototype filter function is rewritten as a weighted sum function of multiple *** the energy constraints of the filter,the relationship between the eigenvectors and the intrinsic interference function is established,and the function problem is transformed into an optimization problem for the weighted *** the interior point method,the most suitable weight is found to obtain the minimum intrinsic interference *** analysis and simulation results show that compared with the prototype filters such as Type1 and CaseC,the DPSS filter applying the proposed optimization algorithm can effectively suppress the intrinsic interference of the system and obtain a better bit error rate(BER)performance.

关键词： filter bank multicarrier-quadrature amplitude modulation(FBMC-QAM) intrinsic interference discrete prolate spheroidal sequences(DPSS) interior point method

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Production and test of sPHENIX W/SciFiber electromagnetic calorimeter blocks in China

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Nuclear Science and Techniques 2024年第8期35卷 167-176页

作者： xiao‑Zhou Yu Xi‑Yang Wang Wei‑Hu ma Shi‑Hong Fu Peng‑Fei Sun Jin‑Xing Song Wan‑Bing He Yang Shen Long ma Jin‑Hui Chen Huan‑zhong Huang Si‑Guang Wang Jing Zhou xiao‑Mei Li Institute of Modern Physics Fudan UniversityShanghai 200433China Key Laboratory of Nuclear Physics and Ion‑Beam Application(MOE) Fudan UniversityShanghai 200433China Science and Technology on Nuclear Data Laboratory China Institute of Atomic EnergyBeijing 102413China Department of Physics and Astronomy University of CaliforniaLos AngelesCA 90095USA State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

The sPHENIX experiment is a new generation of large acceptance detectors at the relativistic heavy ion collider at Brookhaven National Laboratory,with scientific goals focusing on probing the strongly interacting Quark–Gluon plasma with hard probes of jets,open heavy flavor particles,andγ*** EMCal detector,which covers the pseudo-rapidity region of|η|≤1.1,is an essential subsystem of *** this study,we focused on producing and testing EMCal blocks covering a pseudo-rapidity of|η|∈[0.8,1.1].These,in conjunction with the central pseudo-rapidity EMCal blocks,significantly enhance the sPHENIX physics capability of the jet andγparticle *** this paper,the detector module production and testing of sPHENIX W-powder/scintillating fiber(W/ScFi)electromagnetic calorimeter blocks are *** selection of the tungsten powder,mold fabrication,QA procedures,and cosmic ray test results are discussed.

关键词： sPHENIX Tungsten/scintillating fiber electromagnetic calorimeter Cosmic ray test

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Activation Redistribution Based Hybrid Asymmetric Quantization Method of Neural Networks

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工程与科学中的计算机建模(英文) 2024年第1期138卷 981-1000页

作者： Lu Wei zhong ma Chaojie Yang R&D Innovation Center Xi’an Microelectronics Technology InstituteXi’an710065China

The demand for adopting neural networks in resource-constrained embedded devices is continuously *** is one of the most promising solutions to reduce computational cost and memory storage on embedded *** order to reduce the complexity and overhead of deploying neural networks on Integeronly hardware,most current quantization methods use a symmetric quantization mapping strategy to quantize a floating-point neural network into an integer ***,although symmetric quantization has the advantage of easier implementation,it is sub-optimal for cases where the range could be skewed and not *** often comes at the cost of lower *** paper proposed an activation redistribution-based hybrid asymmetric quantizationmethod for neural *** proposedmethod takes data distribution into consideration and can resolve the contradiction between the quantization accuracy and the ease of implementation,balance the trade-off between clipping range and quantization resolution,and thus improve the accuracy of the quantized neural *** experimental results indicate that the accuracy of the proposed method is 2.02%and 5.52%higher than the traditional symmetric quantization method for classification and detection tasks,*** proposed method paves the way for computationally intensive neural network models to be deployed on devices with limited computing *** will be available on https://***/ycjcy/Hybrid-Asymmetric-Quantization.

关键词： Quantization neural network hybrid asymmetric accuracy

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Grating-free autofocus for single-pixel microscopic imaging

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Photonics Research 2024年第6期12卷 1313-1321页

作者： GUAN WANG HUAXIA DENG YU CAI MENGCHAO ma XIANG zhong XINGLONG GONG CAS Key Laboratory of Mechanical Behavior and Design of materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China School of Instrument Science and Opto-electronics Engineering Hefei University of TechnologyHefei 230009China

As a computational technology,single-pixel microscopic imaging(SPMI)transfers the target’s spatial information into a temporal *** traditional focusing method of imaging before evaluation is not applicable to the SPMI *** propose a grating-free autofocus strategy derived from the physical mechanism of optical *** the amplitude information of just one high-frequency point in the spectrum is all that is needed to achieve fast autofocus with the SPMI ***,only four patterns need to be cyclically projected,enabling efficient localization of the focal plane based on the measurement *** demonstrate SPMI autofocus experiments at micrometer and even nanometer depths of *** proposed method can be extended to achieve SMPI autofocus with invisible optical pattern illumination.

关键词： optical system illumination

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Transition-metal-catalyzed remote meta-C-H alkylation and alkynylation of aryl sulfonic acids enabled by an indolyl template

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Chinese Chemical Letters 2024年第8期35卷 254-259页

作者： Pengfei Zhang Qingxue ma Zhiwei Jiang xiaohua Xu zhong Jin College of Chemistry State Key Laboratory of Elemento-organic ChemistryNankai UniversityTianjin 300071China Key Laboratory of Xinjiang Native Medicinal and Edible Plant Resource Chemistry College of Chemistry and Environmental SciencesKashi UniversityKashgar 844007China

Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of phenyl ***,with the assistance of a practical biaryl indolyl directing template,palladium-catalyzed remote sp^(2)C-H alkylation of aryl sulfonic acids have been achieved in moderate to good yields with exclusive meta ***,remote meta-selective C-H alkynylation of aryl sulfonic acids was also accomplished with a rhodium *** meta-C-H functionalized products proved to be the superior synthetic precursors,which are difficult to access using the conventional strategy.

关键词： C-H functionalization Aryl sulfonic acid Site-selectivity Transition-metal catalysis Alkylation Alkynylation

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Reinforcement Learning Based Quantization Strategy Optimal Assignment Algorithm for Mixed Precision

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Computers, materials & Continua 2024年第4期79卷 819-836页

作者： Yuejiao Wang zhong ma Chaojie Yang Yu Yang Lu Wei Xi’an Microelectronics Technology Institute Xi’an710065China

The quantization algorithm compresses the original network by reducing the numerical bit width of the model,which improves the computation speed. Because different layers have different redundancy and sensitivity to databit width. Reducing the data bit width will result in a loss of accuracy. Therefore, it is difficult to determinethe optimal bit width for different parts of the network with guaranteed accuracy. Mixed precision quantizationcan effectively reduce the amount of computation while keeping the model accuracy basically unchanged. In thispaper, a hardware-aware mixed precision quantization strategy optimal assignment algorithm adapted to low bitwidth is proposed, and reinforcement learning is used to automatically predict the mixed precision that meets theconstraints of hardware resources. In the state-space design, the standard deviation of weights is used to measurethe distribution difference of data, the execution speed feedback of simulated neural network accelerator inferenceis used as the environment to limit the action space of the agent, and the accuracy of the quantization model afterretraining is used as the reward function to guide the agent to carry out deep reinforcement learning training. Theexperimental results show that the proposed method obtains a suitable model layer-by-layer quantization strategyunder the condition that the computational resources are satisfied, and themodel accuracy is effectively *** proposed method has strong intelligence and certain universality and has strong application potential in thefield of mixed precision quantization and embedded neural network model deployment.

关键词： Mixed precision quantization quantization strategy optimal assignment reinforcement learning neural network model deployment

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