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An interlaminar damage shell model for typical composite structures

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Chinese Journal of Aeronautics 2024年第1期37卷 118-137页

作者： jie ZHOU zhen WU zhengliang liU Xiaohui REN School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China National Key Laboratory of Strength and Structural Integrity Xi’an 710065China School of Mechanical Engineering Xi’an Aeronautical UniversityXi’an 710065China

Using the plate/shell elements in commercial software,accurate analysis of interlaminar initial damage in typical composite structures is still a challenging *** propose an accurate and efficient model for analysis of interlaminar initial damage,the following work is carried out:(A)A higher-order theory is firstly proposed by introducing the local Legendre polynomials,and then a novel shell element containing initial damage prediction is developed,which can directly predict transverse shear stresses without any postprocessing *** variables at each node are independent of number of layers,so the proposed model is more efficient than the 3D-FEM.(B)Compression experiment is carried out to verify the capability of the proposed *** results obtained from the proposed model are in good agreement with experimental data.(C)Several examples have been analyzed to further assess the capability of the proposed model by comparing to the 3D-FEM ***,accuracy and efficiency have been evaluated in different damage criterion by comparing with the selected *** numerical results show that the proposed model can well predict the initial interlaminar damage as well as other ***,the model is implemented with UEL subroutine,so that the present approach can be readily utilized to analyze the initial damage in typical composite structures.

关键词： Compression experiment Finite element method Initial damage Interlaminar stress Plate/shell element

In Vitro Study on Mg-Sn-Mn Alloy as Biodegradable Metals

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Journal of Materials Science & Technology 2014年第7期30卷 675-685页

作者： zhen zhen Tingfei Xi Yufeng zheng li li Lugee li Center for Biomedical Materials and Tissue Engineering Academy for Advanced Interdisciplinary StudiesPeking University Biomedical Engineering Research Center Shenzhen InstitutePeking University Department of Materials Science and Engineering College of EngineeringPeking University Center for Biomedical Materials and Engineering Harbin Engineering University Dongguan EONTEC Company Ltd

The mechanical properties, chemical properties and biocompatibility of Mg-3Sn-0.5Mn alloy were tested. A series of in vitro evaluations such as tensile test, static and dynamic immersion test, hemocompatibility test as well as cytotoxicity test were presented, with commercial magnesium alloy WE43 as the control. Mg-3Sn-0.5Mn alloy possesses suitable strength and superior ductility compared with WE43 and AZ31. Static immersion and dynamic degradation tests showed more uniform degradation with a more moderate rate for Mg-3Sn-0.5Mn alloy （0.34 mm/y in static condition and 0.25 mm/y in dynamic condition） compared with WE43 alloy （0.42 mm/y in static condition and 0.33 mm/y in dynamic condition） in Hank＇s solution. Blood compatibility evaluation suggested that Mg-3Sn-0.5Mn alloy had no destructive effect on erythrocyte and showed excellent anti-thrombogenicity to blood system. Besides, Mg-3Sn-0.5Mn alloy showed no inhibition effect to L929 metabolic activity and mild toxicity to vascular smooth muscle cell （VSMC） in preliminary cell viability assessment. By considering its excellent mechanical strength, corrosion resistance, low ion release rate and good biocompatibility, Mg-3Sn-0.5Mn alloy may be a promising economical candidate as biomedical implant material for load-bearing clinical applications in the future.

关键词： Mg-3Sn-0.5Mn alloy Corrosion Dynamic immersion Static immersion Biodegradable material

Direct demonstration of triplet excimer in purely organic room temperature phosphorescence through rational molecular design

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light(Science & Applications) 2022年第6期11卷 1218-1226页

作者： zhenjiang liu Yu Tian jie Yang Aisen li Yunsheng Wang Jia Ren Manman Fang Ben Zhong Tang zhen li Institute of Molecular Aggregation Science Tianjin UniversityTianjin 300072China Joint School of National University of Singapore Tianjin UniversityInternational Campus of Tianjin UniversityBinhai New CityFuzhou 350207China Shenzhen Institute of Molecular Aggregate Science and Engineering School of Science and EngineeringThe Chinese University of Hong KongShenzhenGuangdong 518172China Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of ChemistryTianjin UniversityTianjin 300072China Department of Chemistry Wuhan UniversityWuhan 430072China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Organic luminogens with room temperature phosphorescence(RTP)have been paid great attention and developed rapidly for their wide application *** now,the internal mechanism and source of phosphorescence are still obscure,especially for the relationship between molecular dimer and RTP ***,we designed and synthesized eight phenothiazine 5,5-dioxide derivatives to directly reveal how the monomer and dimer in packing affect the RTP *** with strongπ-πstacking(θ<20.66°;d<3.86A)lead to pure triplet excimer emission,while those with weakπ-πstacking(27.02°<θ<40.64°;3.84A

关键词： RTP excimer rational

■-dressing Method for the Coupled Two-component Kundu-Eckhaus Equations

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Acta Mathematicae Applicatae Sinica 2024年

作者： zhen-jie NIU Biao li School of Mathematics and Statistics Ningbo University

In this paper,■-dressing method based on a local 3×3 matrix ■-problem with non-normalization boundary conditions is used to investigate coupled two-component Kundu-Eckhaus ***,we propose a new compatible system with singular dispersion relation,that is time spectral problem and spatial spectral problem of coupled two-component Kundu-Eckhaus equations via constraint ***,we derive a hierarchy of nonlinear evolution equations by introducing a recursive *** last,by solving constraint matrixes,a spectral transform matrix is given which is sufficiently important for finding soliton solutions of potential function,and we obtain N-soliton solutions of coupled two-component Kundu-Eckhaus equations.

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疾病空间异质性定量分析方法及其应用

山东大学学报（医学版） 2002年第6期40卷 485-488页

作者：薛付忠王洁贞范丽炜王振光山东大学公共卫生学院山东大学计财处山东大学科技处

目的:探讨疾病空间异质性理论及其定量分析方法。方法:在疾病空间相关-自相关假设下,定义疾病空间化变量,构造疾病空间异质性的变异函数模型,利用该模型将疾病空间异质性分解成各定量组分,进而确定疾病空间异质性程度和变化尺度;定义疾... 详细信息

目的:探讨疾病空间异质性理论及其定量分析方法。方法:在疾病空间相关-自相关假设下,定义疾病空间化变量,构造疾病空间异质性的变异函数模型,利用该模型将疾病空间异质性分解成各定量组分,进而确定疾病空间异质性程度和变化尺度;定义疾病空间异质性参数的流行病学含义。结果:获得疾病空间异质性的定量分析方法和流行病学参数,并以对肾综合征出血热空间异质性的分析验证方法的科学性。结论:该方法能准确刻画疾病空间异质性特点,解释疾病的地理流行病学机制。

关键词：疾病空间异质性定量分析变异函数地理流行病学

Peak-like three-dimensional CoFe_(2)O_(4)/carbon nanotube decorated bamboo fabrics for simultaneous solar-thermal evaporation of water and photocatalytic degradation of bisphenol A

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Journal of Materials Science & Technology 2024年第12期179卷 40-49页

作者： Rui-jie Pan Jing Wu Jin Qu Tingting Zhang Fan-zhen Jiao Mang Zhao Meng-Yan Han Xiaofeng li Zhong-zhen Yu State Key Laboratory of Organic-Inorganic Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Advanced Functional Polymer Composites Beijing University of Chemical TechnologyBeijing 100029China

Catalytic CoFe_(2)O_(4) and solar-thermal carbon nanotube decorated bamboo fabrics(CCBF)are fabricated for integrating efficient solar steam generation from wastewater with catalytic degradation of its organic *** to the numerous porous channels and polar groups of bamboo fabric and the efficient solar-thermal energy conversion of black carbon nanotubes,the porous and hydrophilic CCBF exhibits fast upward transport of water,efficient solar light absorption,and high solar-thermal energy conversion *** decorated CoFe_(2)O_(4) not only enhances the solar-thermal energy conversion efficiency of CCBF but also activates potassium peroxymonosulfate to generate abundant highly active species for catalytic degradation of bisphenol A(BPA).Furthermore,folding the CCBF into a peak-like 3D evaporator can en-hance solar energy utilization,and gain environmental energy for promoting solar-thermal water evapo-ration and catalytic degradation *** 3D CCBF evaporator achieves a water evaporation rate of 2.72 kg m^(-2) h^(-1) under 1-sun ***,100%of the BPA in the seawater can be degraded within 10 *** exceptional high purification efficiency of 27.72 kg m^(-2) h^(-1) is achieved with the 3D evaporator during a long-term treatment of BPA-containing seawater under 1-sun *** work demonstrates efficient purification of seawater/wastewater with both metal ions and organic pollutants by simultaneous solar-thermal evaporation of water and catalytic degradation of organic pollutants.

关键词： Solar-thermal water evaporation Seawater desalination Catalytic degradation Carbon nanotubes CoFe_(2)O_(4)

Stochastic Optimal Control Problem in Advertising Model with Delay

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Journal of Systems Science & Complexity 2020年第4期33卷 968-987页

作者： CHEN li WU zhen School of Science China University of Mining&TechnologyBeijing 100083China School of Mathematics Shandong UniversityJinan 250100China

This paper investigates the optimal control problem arising in advertising model with delay. The authors reformulate the problem in Hilbert space by stochastic evolution equation and consider the optimal control problem of controlled stochastic evolution system. The necessary and sufficient optimality conditions of the control are established. The proposed approach is different from most existing studies of optimal advertising policy problem with delay. These results are applied to the optimal advertising policy problem under two different structures and the optimal advertising strategies are obtained.

关键词： optimal stochastic Optimal

Improved genetic algorithm based on reinforcement learning for electric vehicle front-end structure optimization design

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Advances in Manufacturing 2024年第3期12卷 556-575页

作者： Feng-Yao Lyu zhen-Fei Zhan Gui-lin Zhou Ju Wang jie li Xin He Chongqing Jiaotong University Chongqing400074People’s Republic of China Changan Automobile Co.Ltd. Chongqing404100People’s Republic of China

The structural optimization of electric vehicles involves numerous design variables and constraints,making it a complex engineering optimization task over the past *** population-based evolutionary algorithms encounter issues such as converging to local optima and lacking population diversity when tackling such optimization ***,the solutions obtained for the optimization may be flawed or *** address these problems,an improved genetic algorithm(GA)based on reinforcement learning is proposed in this *** proposed method introduces a population delimitation method based on individual fitness *** population is divided into two parts:the excellent population and the ordinary population,and different selection and cross-mutation methods are applied to each part *** efficient crossover and mutation methods are then applied to the ordinary population to enhance the generation of excellent ***,the proposed approach replaces the traditional fixed crossover and mutation rates with a dynamic selection method based on reinforcement learning to enhance optimization efficiency.A markov decision process model is constructed based on GA environment in this *** population state determination method and reward method are designed for reinforcement learning in the GA environment,dynamically selecting the most appropriate genetic parameters based on the current state of the ***,the uncertainty in the manufacturing process is introduced into the optimization problem and the case study results demonstrate that the proposed reinforcement learning-based GA significantly outperforms other evolutionary algorithms when applied to solving the structural optimization of electric vehicles.

关键词： Structure optimization Genetic algorithm(GA) Q-learning

From blocker to booster:Harnessing garnet surface chemistry for advanced solid-state electrolytes

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Nano Research 2025年第1期18卷 323-331页

作者： Jun Cheng Xuan Zhou Hongqiang Zhang zhen Zeng Yuanyuan li Yulong Zhu Yingsheng liao lijie Ci Deping li State Key Laboratory of Precision Welding and Joining of Materials and Structures School of Materials Science and EngineeringHarbin Institute of Technology(Shenzhen)Shenzhen 518055China

Garnet electrolytes with high ionic conductivity and electrochemical stability are widely used as fillers to fabricate composite solid electrolytes(CPEs)within polymer ***,the performance of CPEs is significantly influenced by the surface characteristics of the garnet ***,the impact of garnet surface characteristics on CPEs was systematically investigated and a conversion from a typically unstable and Lewis basic surface to a more stable Lewis acidic surface was realized,which is shown to be more conductive to the improved performance of *** simultaneously removing the li_(2)CO_(3)layer and applying a li-Al-O coating,the influence of surface characteristics on CPEs was *** Lewis acid li-Al-O surface coating not only promotes lithium salt dissociation,improving the ionic conductivity and ionic transfer number,but also prevents the reformation of the passive Lewis basic li_(2)CO_(3)*** to garnet with a Lewis basic li_(2)CO_(3)surface,the garnet modified with a Lewis acid li-Al-O coating enhances CPEs,which exhibit an improved critical current density of 1.0 mA·cm^(-2)and highly stable lithium symmetric cell cycling for 400 h at 0.2 mA·cm^(-2).This research highlights the importance of surface chemistry in the design of high-performance solid-state batteries and presents a strategic modification approach for garnetbased CPEs.

关键词： garnet electrolyte composite solid electrolyte surface chemistry all-solid-state batteries