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Mechanical and damping performances of TPMS lattice metamaterials fabricated by laser powder bed fusion

China Foundry 2024年第4期21卷 327-333页

作者： Yan-peng Wei Huai-qian Li jing-jing Han Ying-chun ma Hao-ran Zhou jing-chang Cheng Jian Shi Zhi-quan Miao Bo Yu Feng Lin National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China

Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ***,its vibration and noise reduction,and damping properties have not been fully ***,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static *** modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal *** the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,*** results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.

关键词： lattice metamaterials TPMS energy absorption damping laser powder bed fusion

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An Initial Perturbation Method for the Multiscale Singular Vector in Global Ensemble Prediction

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Advances in Atmospheric Sciences 2024年第3期41卷 545-563页

作者： Xin LIU jing CHEN Yongzhu LIU Zhenhua HUO Zhizhen XU Fajing CHEN jing WANG Yanan ma Yumeng HAN School of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing 210044China Chinese Academy of Meteorological Sciences Beijing 100081China Cma Earth System Modeling and Prediction Centre(CEMC) Beijing 100081China Key Laboratory of Earth System Modeling and Prediction of China Meteorological Administration Beijing 100081China Tianjin Meteorological Observatory Tianjin 300074China China Meteorological Administration Xiong’an Atmospheric Boundary Layer Key Laboratory Hebei 071799China

Ensemble prediction is widely used to represent the uncertainty of single deterministic Numerical Weather Prediction(NWP) caused by errors in initial conditions(ICs). The traditional Singular Vector(SV) initial perturbation method tends only to capture synoptic scale initial uncertainty rather than mesoscale uncertainty in global ensemble prediction. To address this issue, a multiscale SV initial perturbation method based on the China Meteorological Administration Global Ensemble Prediction System(Cma-GEPS) is proposed to quantify multiscale initial uncertainty. The multiscale SV initial perturbation approach entails calculating multiscale SVs at different resolutions with multiple linearized physical processes to capture fast-growing perturbations from mesoscale to synoptic scale in target areas and combining these SVs by using a Gaussian sampling method with amplitude coefficients to generate initial perturbations. Following that, the energy norm,energy spectrum, and structure of multiscale SVs and their impact on GEPS are analyzed based on a batch experiment in different seasons. The results show that the multiscale SV initial perturbations can possess more energy and capture more mesoscale uncertainties than the traditional single-SV method. Meanwhile, multiscale SV initial perturbations can reflect the strongest dynamical instability in target areas. Their performances in global ensemble prediction when compared to single-scale SVs are shown to(i) improve the relationship between the ensemble spread and the root-mean-square error and(ii) provide a better probability forecast skill for atmospheric circulation during the late forecast period and for short-to medium-range precipitation. This study provides scientific evidence and application foundations for the design and development of a multiscale SV initial perturbation method for the GEPS.

关键词： multiscale uncertainty singular vector initial perturbation global ensemble prediction system

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S-(1,3-Dioxoisoindolin-2-yl)O,O-diethyl phosphorothioate (SDDP): A practical electrophilic reagent for the phosphorothiolation of electron-rich compounds

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Chinese Chemical Letters 2024年第5期35卷 151-154页

作者： Ze-Yuan ma mei Xiao Cheng-Kun Li Adedamola Shoberu Jian-Ping Zou Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry and Chemical EngineeringSoochow UniversitySuzhou 215123China

An efficient synthesis of the electrophilic reagent,S-(1,3-dioxoisoindolin-2-yl)O,O-diethyl phosphorothioate(SDDP)is ***,the synthetic applications of SDDP wherein the transfer of the SP(O)(OEt)_(2) moiety occurs were *** this manner,SDDP underwent facile SP(O)(OEt)_(2) transfer with electron-rich substrates such as ketones,indoles,and thiols to formα-phosphorothiolated ketones,3-phosphorothiolated indoles and S-phosphorothiolated thioethers,respectively.

关键词： Electrophilic reagent Phosphorothiolation Electrophilic substitution

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Overview of the immunological mechanisms in hepatitis B virus reactivation:Implications for disease progression and management strategies

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World Journal of Gastroenterology 2024年第10期30卷 1295-1312页

作者： Hui ma Qing-Zhu Yan jing-Ru ma Dong-Fu Li Jun-Ling Yang Department of Clinical Laboratory The Second Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina Department of Ultrasound Medicine The Second Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina Digestive Diseases Center Department of Hepatopancreatobiliary MedicineThe Second Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina Department of Respiratory and Critical Care Medicine The Second Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina

Hepatitis B virus(HBV)reactivation is a clinically significant challenge in disease *** review explores the immunological mechanisms underlying HBV reactivation,emphasizing disease progression and *** delves into host immune responses and reactivation’s delicate balance,spanning innate and adaptive *** factors’disruption of this balance,as are interac-tions between viral antigens,immune cells,cytokine networks,and immune checkpoint pathways,are ***,the roles of T cells,natural killer cells,and antigen-presenting cells are discussed,highlighting their influence on disease *** reactivation’s impact on disease severity,hepatic flares,liver fibrosis progression,and hepatocellular carcinoma is *** strategies,including anti-viral and immunomodulatory approaches,are critically *** role of prophylactic anti-viral therapy during immunosuppressive treatments is explored alongside novel immunotherapeutic interventions to restore immune control and prevent *** conclusion,this compre-hensive review furnishes a holistic view of the immunological mechanisms that propel HBV *** a dedicated focus on understanding its implic-ations for disease progression and the prospects of efficient management stra-tegies,this article contributes significantly to the knowledge *** more profound insights into the intricate interactions between viral elements and the immune system will inform evidence-based approaches,ultimately enhancing disease management and elevating patient *** dynamic landscape of management strategies is critically scrutinized,spanning anti-viral and immunomodulatory *** role of prophylactic anti-viral therapy in preventing reactivation during immunosuppressive treatments and the potential of innovative immunotherapeutic interventions to restore immune control and proactively deter reactivation.

关键词： Hepatitis B virus reactivation Immunological mechanisms Disease progression management strategies Immune response

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Grain size refinement of additive manufactured Ce-TZP ceramics by coupled two-step pre-sintering and HIP

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Journal of Advanced Ceramics 2024年第5期13卷 621-629页

作者： Ruoshi Zhao Hongbing Yang Xintong Liu Hezhen Li Chang-An Wang jing ma Yanhao Dong State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Ceria-stabilized tetragonal zirconia polycrystal(Ce-TZP)has exceptional fracture toughness and flaw tolerance due to facile t‒m phase transformation ***,its wider-range applications are limited by its relatively low strength due to its large grain size and low transformation stress,which results in yield-like ***,we combined additive manufacturing(AM),pressureless two-step sintering,and hot isostatic pressing(HIP),and addressed the challenging grain size refinement problem in *** successfully produced dense ultrafine-grained Ce-TZP ceramics with an average grain size below 500 nm,a three-point bending strength above 800 MPa,and a single-edge-notch-beam fracture toughness in the range of 11‒12 MPa·m^(1/2).The critical roles of processing design,mixed Ce valences,and ***-stabilization of tetragonal polymorphs were *** work offers insights and strategies for the future development of stronger and tougher Ce-TZP ceramics that can compete with tetragonal yttria-stabilized zirconia in various applications,including additive manufacturing.

关键词： zirconia additive manufacturing(AM) two-step sintering hot isostatic pressing(HIP) grain size refinement

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Liquid-phase epitaxial layer by layer brushing fabrication of metalorganic frameworks films

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Nano Research 2024年第6期17卷 5698-5704页

作者： Li-mei Chang Rui Zhai Zhi-Zhou ma Jian-Dong Huang Zhi-Gang Gu Jian Zhang College of Chemistry Fuzhou UniversityFuzhou 350108China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

Development of metal-organic framework(MOF)films is of great importance to expand their ***,we report a facile and universal method of liquid-phase epitaxial(LPE)layer by layer(LBL)brushing approach for fabricating MOF films on various substrates in a high-throughput *** MOF films preparation method offers a great prospective to cost-effectively construct films with short preparation time and little reagent ***,this LBL brushing approach has been implemented successfully to assemble various MOF films,including HKUST-1,zeolitic imidazolate framework-8(ZIF-8),Cu(bdc),and Cu_(2)(L)_(2)P(L=bdc,ndc,and cam;P=dabco and bipy).Afterwards,the classic MOF HKUST-1 and ZIF-8 films were grown on sensor chip electrode and porous fiber support for good volatile organic compounds(VOCs)selective sensing and water purification *** study demonstrates that this LBL brushing preparation method can be employed to synthesize various MOF films with a variety of characteristics to realize their sensing and separation applications.

关键词： metal-organic framework porous materials layer by layer fabrication film

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Lightweight Dual‑Functional Segregated Nanocomposite Foams for Integrated Infrared Stealth and Absorption‑Dominant Electromagnetic Interference Shielding

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Nano-Micro Letters 2024年第11期16卷 38-55页

作者： Zhonglei ma Ruochu Jiang Jiayao jing Songlei Kang Li ma Kefan Zhang Junxian Li Yu Zhang Jianbin Qin Shuhuan Yun Guangcheng Zhang MOE Key Laboratory of material Physics and Chemistry Under Extraordinary Conditions Shaanxi Key Laboratory of Macromolecular Science and TechnologySchool of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China College of Chemistry and Chemical Engineering Key Laboratory of Auxiliary Chemistry and Technology for Chemical IndustryMinistry of EducationShaanxi University of Science and TechnologyXi’an 710072People’s Republic of China Department of Mechanical and Industrial Engineering University of Toronto5 King’s College RoadTorontoON M5S 3G8Canada Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135People’s Republic of China

Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable ***,lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO_(2)(SC-CO_(2))foaming combined with hydrogen bonding assembly and compression molding *** obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity,and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated ***,the segregated nanocomposite foams present a large radiation temperature reduction of 70.2℃ at the object temperature of 100℃,and a significantly improved EM wave absorptivity/reflectivity(A/R)ratio of 2.15 at an ultralow Ti_(3)C_(2)T_(x) content of 1.7 vol%.Moreover,the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression *** results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace,weapons,military and wearable electronics.

关键词： Segregated nanocomposite foams Microcellular structures Infrared stealth EMI shielding Low infrared emissivity

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Feasible Synthesis of N,O-Bidentate Difluoroboron Chromophores through Direct Functionalization of Quinoxalin-2(1H)-ones with Ketones in One Shot

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Chinese Journal of Chemistry 2024年第13期42卷 1481-1486页

作者： Shuaichen Zhang jing Zhang Xiang Ling Yifan Zhao Yue ma Peng Sun State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs Artemisinin Research Center and Institute of Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijing 100700China Department of Pharmaceutics School of PharmacyChina Pharmaceutical UniversityState Key Laboratory of Natural MedicinesNanjingJiangsu 210009China

Organic difluoroboron complexes are a kind of potential platforms for a wide range of applications owing to their excellent photophysical ***,we have explored a simple and direct synthesis methodology for a library of N,O-bidentate difluoroboron complexes from quinoxalin-2(1H)-ones and ketones in one *** photophysical properties of the generated complexes were evaluated and the application potential of these compounds on subcellular imaging was also explored.

关键词： N,O-Bidentate difluoroboron Chromophores Quinoxalin-2(1H)-ones Ketones/Green chemistry Synthetic method C-CcouplingI Boron

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Nitrogen–sulfur co-doped porous carbon derived from asphalt as efficient catalyst for oxygen reduction

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Rare Metals 2024年第1期43卷 380-388页

作者： jing-Sheng ma Ming-Zai Wu Ling Chen Li-Xing Zhang Ying Xiong Key Laboratory of Structure and Functional Regulation of Hybrid materials Ministry of EducationInstitute of EnergyHefei Comprehensive National Science CenterAnhui UniversityHefei 230601China

As an environment-friendly and low-cost petrochemical by-product, asphalt has great potential in the preparation of metal-free oxygen reduction electrocatalysts with excellent performance and outstanding stability. In this paper, we converted asphalt into porous carbon nanosheets by a simple activation method, using potassium citrate as the swelling agent.

关键词： stability porous catalyst

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Enhancing personalized exercise recommendation with student and exercise portraits

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Journal of Electronic Science and Technology 2024年第2期22卷 91-109页

作者： Wei-Wei Gao Hui-Fang ma Yan Zhao jing Wang Quan-Hong Tian College of Computer Science and Engineering Northwest Normal UniversityLanzhou730070China Computer Center of Gansu Province Lanzhou730070China

The exercise recommendation system is emerging as a promising application in online learning scenarios,providing personalized recommendations to assist students with explicit learning *** solutions generally follow a collaborative filtering paradigm,while the implicit connections between students(exercises)have been largely *** this study,we aim to propose an exercise recommendation paradigm that can reveal the latent connections between student-student(exercise-exercise).Specifically,a new framework was proposed,namely personalized exercise recommendation with student and exercise portraits(PERP).It consists of three sequential and interdependent modules:Collaborative student exercise graph(CSEG)construction,joint random walk,and recommendation list ***,CSEG is created as a unified heterogeneous graph with students’response behaviors and student(exercise)***,a joint random walk to take full advantage of the spectral properties of nearly uncoupled markov chains is performed on CSEG,which allows for full exploration of both similar exercises that students have finished and connections between students(exercises)with similar ***,we propose to optimize the recommendation list to obtain different exercise *** analyses of two public datasets,the results demonstrated that PERP can satisfy novelty,accuracy,and diversity.

关键词： Educational data mining Exercise recommend Joint random walk Nearly uncoupled markov chains Optimization Personalized learning

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