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Preparation of Flaky Hexagonal Nanoporous Au-Cu and Au Particles via Dealloying

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Acta Metallurgica Sinica(English Letters) 2022年第11期35卷 1777-1786页

作者： Jing Deng Yuan-Yun Zhao Yong Shen Chuntao Chang Qiang Li School of Physics Science and Technology Xinjiang UniversityUrumqi 830046China Neutron Scattering Technical Engineering Research Center School of Mechanical EngineeringDongguan University of TechnologyDongguan 523808China Guangdong-HongKong-Macao Joint Laboratory for Neutron Scattering Science and TechnologyDongguan University of TechnologyDongguan 523808China Instituteof Metal Research Chinese Academy of SciencesShenyang 110016China

Nanoporous metals have attracted signifi cant attention owing to their excellent physical,chemical,and biological properties.However,preparing ultrafi ne nanoporous metal particles(1–5μm)with specifi c geometries remains challenging.Herein,we report a simple strategy to prepare ultrafi ne fl aky hexagonal nanoporous Au-Cu and Au particles via dealloying.Mg-based alloy ribbons with ultrafi ne fl aky hexagonal Mg-Au(Cu)-Gd particles dispersed in a Mg-Cu(Au)-Gd metallic glassy matrix were prepared.The size and morphology of the precipitated fl aky hexagonal Mg-Au(Cu)-Gd particles were controlled by the solidifi cation process of a Mg 61 Cu 21 Au 7 Gd 11 alloy melt.Ultrafi ne fl aky hexagonal nanoporous Au-Cu particles(diagonal diameter 2.58±0.44μm,ligament size~28 nm),Au-1 particles(diagonal diameter 2.38±0.35μm,ligament size~83 nm)and Au-2 particles(diagonal diameter 2.39±0.44μm,ligament size~66 nm)were prepared via ultrasonic-assisted dealloying of Mg 61 Cu 21 Au 7 Gd 11 alloy ribbons in 0.25 M HCl/ethanol,1 M HCl/ethanol and 0.25 M HNO 3/ethanol solutions,respectively.The ultrafi ne fl aky hexagonal nanoporous Au-Cu and Au particles with a large specifi c surface area have a uniform particle size and shape,implying that they possess adequate powder fl uidity and excellent catalytic properties.Moreover,the formation mechanism of the MgAu(Cu)Gd phase in solidifi ed Mg-Cu-Au-Gd alloys was discussed.This study provides a novel approach for synthesizing nanoporous metal particles with a specifi c geometry.

关键词： Metallic glasses Mg-based alloys Dealloying Nanoporous particles Mg-Au-Gd phase

Three-stage Nonlinear Thermal Model for Microspeakers in Mobile Phones

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Sound & Vibration 2018年第5期52卷 28-33页

作者： Zhiliang Zhang Yong Shen Jie Xia Yuchen shen Institute of Acoustics Key Laboratory of Modern Acoustics of Ministry of EducationNanjing UniversityNanjing210093China

Since microspeakers are widely used in mobile phones,high power is usually applied to obtain sufficient output sound pressure.However,the electric power is almost converted into heat,leading to the thermal problem in microspeakers.Compared with large loudspeaker,microspeakers are smaller and the under yoke is relatively closed,causing the heat transfer more complex.In this study,a three-stage nonlinear thermal model was proposed for analyzing the thermal behavior in microspeakers.The inside air is a buffer area between the voice coil and magnet,and modeled as a middle stage of the heat transfer.The forced convection is still significant in microspeakers while the eddy current can be ignored.In order to obtain the thermal parameters of the model,a corresponding parameter identification method was put forward.The basic linear parameters and forced convection parameters were all obtained by measuring and fitting the temperature curves of voice coil at different single tones.A series of experiments were conducted to verify the proposed model and parameter identification method,and the results showed good aggrement between the measured and predicted temperature curves for different input signals.The proposed model was valid and accurate,and may be helpful for the design and application of microspeakers.

关键词： Microspeakers heat transfer thermal model mobile phones

Perception of Nonlinear Distortion in Music Signals Reproduced by Microspeakers

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Sound & Vibration 2018年第5期52卷 6-11页

作者： Pei Yu Yong Shen Ziyun Liu Institute of Acoustics Key Laboratory of Modern Acoustics of Ministry of EducationNanjing UniversityNanjing210093China

A lot of work has focused on compensating nonlinear distortions ofthe microspeaker under large excitation, yet it is unclear at which levelthe effect of nonlinear distortion is imperceptible or not annoying. Inthis study virtual listening tests were performed to evaluate thedeterioration of sound quality in music signals with different levels ofnonlinear distortion by a microspeaker. Binaural recordings of themusic played by the microspeaker were made at different voltagelevels, adjusted to the same RMS power, and afterwards reproducedby a low distortion reference headphone. The “double-blind triple-stimuluswith hidden reference” method was used in the listening tests. Listenerswere required to not only discern the distortion, but also rank theseverity of the distortion. The effects of several factors includingsubject, program material and distortion level on the perceiveddistortion are discussed.

关键词： Nonlinear distortion microspeaker virtual listening test

Green rusts-derived iron oxide nanostructures catalyze NO reduction by CO

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Green Energy & Environment 2023年第2期8卷 499-508页

作者： Ping Wang Xiaoling Mou yong Li Wenjie shen Hangzhou Institute of Advanced Studies Zhejiang Normal UniversityHangzhou311231China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China

Green rusts with brucite-like layers of hydroxide intercalated with anions constitute a family of diverse precursors for the synthesis of iron oxides via dehydration,but precise structural control of the resulting oxides with respect to the size and shape at the nanometer level remains challenging due to the easy oxidation of the ferrous species.Herein,we report a new synthetic strategy for the facile preparation of fibrous-like green rusts by using appropriate balancing anions(CO_(3)^(2-)and SO_(4)^(2-))in ethylene glycol to regulate the morphology.Depending on the type of the intercalating anion,the green rusts were converted into hematite with fibrous-or plate-like shapes upon thermal activation.When evaluated in the reaction of NO reduction by CO,these iron oxides showed a prominent shape-dependent catalytic behavior.The fibrous-like Fe_(2)O_(3)was much more catalytically active and structurally robust than the plate-like analogue.Combined spectroscopic and microscopic characterizations on the nanostructured iron oxides revealed that the superior performance of the fibrous-like Fe_(2)O_(3)stemmed from a facile Fe_(2)O_(3)/Fe_(3)O_(4)redox cycle and a higher density of active sites for NO activation.

关键词： Green rust Hematite Morphology NO reduction by CO Redox cycle

Decoding hereditary spastic paraplegia pathogenicity through transcriptomic profiling

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Zoological Research 2023年第3期44卷 650-662页

作者： Nicolas James Ho Xiao Chen yong Lei shen Gu School of Biomedical Sciences Faculty of MedicineThe Chinese University of Hong KongHong Kong SARChina Dr.Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of the Second Affiliated Hospital Zhejiang University School of MedicineHangzhouZhejiang 310058China Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province Zhejiang University School of MedicineHangzhouZhejiang 310058China Zhejiang University-University of Edinburgh Institute&School of Basic Medicine Zhejiang University School of MedicineHangzhouZhejiang 310058China Department of Sports Medicine Zhejiang University School of MedicineHangzhouZhejiang 310058China China Orthopedic Regenerative Medicine Group(CORMed) HangzhouZhejiang310058 China School of Medicine The Chinese University of Hong Kong(Shenzhen)ShenzhenGuangdong 518172China The Chinese University of Hong Kong(shenzhen) Shenzhen Futian Biomedical Innovation R&D CenterShenzhenGuangdong 518172China Key Laboratory for Regenerative Medicine Ministry of EducationSchool of Biomedical SciencesFaculty of MedicineThe Chinese University of Hong KongHong Kong SARChina Kunming Institute of Zoology-The Chinese University of Hong Kong(KIZ-CUHK)Joint Laboratory of Bioresources and Molecular Research of Common Diseases Hong Kong SARChina Hong Kong Branch of CAS Center for Excellence in Animal Evolution and Genetics The Chinese University of Hong KongHong Kong SARChina

Hereditary spastic paraplegia(HSP)is a group of genetic motor neuron diseases resulting from length-dependent axonal degeneration of the corticospinal upper motor neurons.Due to the advancement of next-generation sequencing,more than 70 novel HSP disease-causing genes have been identified in the past decade.Despite this,our understanding of HSP physiopathology and the development of efficient management and treatment strategies remain poor.One major challenge in studying HSP pathogenicity is selective neuronal vulnerability,characterized by the manifestation of clinical symptoms that are restricted to specific neuronal populations,despite the presence of germline disease-causing variants in every cell of the patient.Furthermore,disease genes may exhibit ubiquitous expression patterns and involve a myriad of different pathways to cause motor neuron degeneration.In the current review,we explore the correlation between transcriptomic data and clinical manifestations,as well as the importance of interspecies models by comparing tissue-specific transcriptomic profiles of humans and mice,expression patterns of different genes in the brain during development,and single-cell transcriptomic data from related tissues.Furthermore,we discuss the potential of emerging single-cell RNA sequencing technologies to resolve unanswered questions related to HSP pathogenicity.

关键词： degeneration transcript hereditary

Bending fatigue behavior of thin Zr_(61)Ti_(2)Cu_(25)Al_(12)bulk metallic glass beams for compliant mechanisms application

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Journal of Materials Science & Technology 2021年第30期89卷 1-15页

作者： Diao-Feng Li Ya-Long Yang Yong Shen Jian Xu Institute of Metal Research Chinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

In this work,bending fatigue behavior of thinner Zr_(61)Ti_(2)Cu_(25)Al_(12)(ZT1)BMG beams with thicknesses of 500μm and 100μm were investigated with three-point bending(3PB),to evaluate the reliability and safety of this potentially material used in compliant mechanisms under cyclic bending load.Fatigue endurance limits(FELs)of ZT1 beams with thicknesses of 500μm and 100μm were determined to be 470 MPa,and~0.3 of its tensile strength.Fatigue life and FEL of ZT1 beams in bending are substantially independent of the beam thickness,in the scale from 500μm down to 100μm.Fatigue cracks of all ZT1 beams initiated at the extrinsic microvoids,either indirectly derived from surface scratches during mechanical polishing or originated from as-cast process.However,fatigue crack propagation behavior is highly related to the magnitude of cyclic stress level.By interrupted fatigue tests,larger proportion about 60-70%of fatigue life was spent on crack propagation under high stress level,while crack initiation occupied larger proportion about 80-85%under low stress level.The medium stress level of about 590 MPa almost shared the crack-initiation life and crack-propagation life.In addition,there are two crack deflection mechanisms during cracks steady propagation stage.One mechanism is crack deflection along the interacted shear bands ahead of crack-tip,the other one is crack"jump"from one shear band to another shear band at a certain angle.These two mechanisms alternate dominate the crack propagation process,generating typical staircase-like crack propagation trajectory.Fatigue endurance limits of ZT1 beams in the form of either stress amplitude or strain amplitude are superior to traditional candidate materials in the field of compliant mechanisms,showing that the better reliability and larger deflection deformation can be achieved for flexible members made by ZT1 BMG even under cyclic loading.

关键词： Metallic glasses Bending fatigue Crack initiation Crack propagation Compliant mechanisms

Mental healthcare for psychiatric inpatients during the COVID-19 epidemic

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General Psychiatry 2020年第2期33卷 64-65页

作者： shen Li yong Zhang Department of Psychiatry College of Basic Medical SciencesTianjin Medical UniversityTianjinChina Department of Bipolar Disorder Tianjin Anding HospitalTianjinChina

During this 2019 coronavirus disease(COVID-19)pneumonia epidemic,some experts have expressed concern for the mental healthcare of different types of population groups.However,hospitalised patients with severe mental illness are seemingly overlooked.Psychiatric patients are still a vulnerable group who need to obtain more attention and respect,particularly during the COVID-19 outbreak in China.In this commentary,we briefly introduce the situation of hospitalized patients with severe mental illness and suggest some effective measures that should be rapidly undertaken to reverse current challenges.

关键词： epidemic patients China.

New Version of the CMA-GFS Dynamical Core Based on the Predictor–Corrector Time Integration Scheme

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Journal of Meteorological Research 2023年第3期37卷 273-285页

作者： Xueshun shen yong SU Hongliang ZHANG Jianglin HU CMA Earth System Modeling and Prediction Centre China Meteorological Administration(CMA)Beijing 100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

The operational numerical weather prediction system established by the China Meteorological Administration(CMA),based on the Global/Regional Assimilation and Prediction System(GRAPES)model,adopts the classical semi-implicit semi-Lagrangian(SISL)time integration algorithm.This paper describes a major upgrade to the dynamical core of the CMA global forecast system(CMA-GFS),which was successfully incorporated into operation in 2020.In the upgrade,the classical SISL is further developed into a predictor–corrector scheme,a three-dimensional(3D)reference profile instead of the original isothermal reference profile is applied when implementing the semi-implicit algorithm,and a hybrid terrain-following vertical coordinate system is also applied.The new version of the dynamical core greatly improves the model performance,the time integration reaches second-order accuracy,the time step can be extended by 50%,and the efficiency is greatly improved(by approximately 30%).Atmospheric circulation simulation is systematically improved,and deviations in temperature,wind,and humidity are reduced.The new version of the dynamical core provides a solid foundation for further development of the entire operational system of the CMA.

关键词： Global/Regional Assimilation and Prediction System(GRAPES) China Meteorological Administration global forecast system(CMA-GFS) predictor-corrector three-dimensional(3D)reference profile

DQL-Based Intelligent Scheduling Algorithm for Automatic Driving in Massive MIMO V2I Scenarios

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China Communications 2023年第3期20卷 18-26页

作者： yong Liao Zisong Yin Zhijing Yang Xuanfan shen School of Microelectronics and Communication Engineering Chongqing UniversityChongqing 400044China

Connected and autonomous vehicle(CAV)vehicle to infrastructure(V2I)scenarios have more stringent requirements on the communication rate,delay,and reliability of the Internet of vehicles(Io V).New radio vehicle to everything(NR-V2X)adopts link adaptation(LA)to improve the efficiency and reliability of road safety information transmission.In order to solve the problem that the existing LA scheduling algorithms cannot adapt to the Doppler shift and complex fast time-varying channel in V2I scenario,resulting in low reliability of information transmission,this paper proposes a deep Q-learning(DQL)-based massive multiple-input multiple-output(MIMO)LA scheduling algorithm for autonomous driving V2I scenario.The algorithm combines deep neural network(DNN)with Q-learning(QL)algorithm,which is used for joint scheduling of modulation and coding scheme(MCS)and space division multiplexing(SDM).The system simulation results show that the algorithm proposed in this paper can fully adapt to the different channel environment in the V2I scenario,and select the optimal MCS and SDM for the transmission of road safety information,thereby the accuracy of road safety information transmission is improved,collision accidents can be avoided,and bring a good autonomous driving experience.

关键词： NR autonomous driving V2I link adap-tation massive MIMO deep Q-learning