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Polyamides Containing Thiadiazole Units:Synthesis and Optical Properties

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Chinese Journal of Polymer Science 2014年第3期32卷 292-304页

作者： Zhi-min li 张刚 Dong-sheng li 杨杰 College of Polymer Materials Science and Engineering of Sichuan University Institute of Materials Science & Technology Analytical & Testing CenterSichuan University State Key Laboratory of Polymer Materials Engineering (Sichuan University)

Highly refractive and transparent polyamides containing thiadiazole units have been developed. These polymers were prepared by a polycondensation reaction of 4,4＇-（1,3,4-thiadiazole-2,5-thio） his（methylene） dibenzoyl chloride （TDTBM-DC） and diamine which contained thioether （--S--） and sulfone units. They showed good thermal stabilities such as a relatively high glass transition temperature of 206-233℃ and a 5% weight-loss temperature （T5%） of 376-395 ℃. The optical transmittance of the polymer at 450 nm is higher than 83%. The heterocycle units and plural --S-- linkages provide the polymer with a high refractive index of 1.716-1.725 at 633 nm and a low birefringence of 0.003-0.004. Also they showed improved solubility in polar aprotic solvents and could form moderate strength films with tensile strength of 72.8-83.1 MPa and storage modulus of 1.0-1.8 GPa （at 200 ℃）.

关键词： Synthesis Optical property Soluble Heterocycle.

Public-key encryption and authentication of quantum information

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Science China(Physics,Mechanics & Astronomy) 2012年第9期55卷 1618-1629页

作者： liANG min YANG li State Key Laboratory oflnformation Security Institute of Information Engineering Chinese Academy of Sciences Beijing 100195 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Public-key cryptosystems for quantum messages are considered from two aspects:public-key encryption and public-key ***,we propose a general construction of quantum public-key encryption scheme,and then construct an informationtheoretic secure ***,we propose a quantum public-key authentication scheme,which can protect the integrity of quantum *** scheme can both encrypt and authenticate quantum *** is information-theoretic secure with regard to encryption,and the success probability of tampering decreases exponentially with the security parameter with regard to *** with classical public-key cryptosystems,one private-key in our schemes corresponds to an exponential number of public-keys,and every quantum public-key used by the sender is an unknown quantum state to the sender.

关键词： quantum cryptography authentication quantum public-key private quantum channel

Atom Probe and Mssbauer Spectroscopy Investigations of Cementite Dissolution in a Cold Drawn Eutectoid Steel

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Journal of Materials Science & Technology 2010年第9期26卷 776-782页

作者： Na min Wei li Hongyan li Xuejun Jin School of Materials Science an-d Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Mssbauer spectrum and three dimensional atom probes（3DAP） were combined to investigate the mechanism of cementite dissolution in a cold-drawn eutectoid steel at a true strain of *** experimental results suggest that the dislocations play an important role in the dissolution of the cementite by sweeping across the nano-scaled cementite,and transferring carbon from cementite to ferrite inducing cementite *** mechanism of cementite dissolution in the steel is discussed in association with the investigation of nonstoichiometric cementite structure after heavy deformation.

关键词： Eutectoid steel Cementite Three dimensional atoms probe Mssbauer spectrum

Rail Surface Defect Detection Based on Improved UPerNet and Connected Component Analysis

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Computers, Materials & Continua 2023年第10期77卷 941-962页

作者： Yongzhi min Jiafeng li Yaxing li School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou730070China Gansu Provincial Engineering Research Center for Artificial Intelligence and Graphics&Image Lanzhou Jiaotong UniversityLanzhou730070China State Grid Gansu Electric Power Baiyin Power Supply CompanyBaiyin730900China

To guarantee the safety of railway operations,the swift detection of rail surface defects becomes *** methods of manual inspection and conventional nondestructive testing prove inefficient,especially when scaling to extensive railway ***,the unpredictable and intricate nature of defect edge shapes further complicates detection *** these challenges,this paper introduces an enhanced Unified Perceptual Parsing for Scene Understanding Network(UPerNet)tailored for rail surface defect ***,the Swin Transformer Tiny version(Swin-T)network,underpinned by the Transformer architecture,is employed for adept feature *** approach capitalizes on the global information present in the image and sidesteps the issue of inductive *** model’s efficiency is further amplified by the windowbased self-attention,which minimizes the model’s parameter *** implement the cross-GPU synchronized batch normalization(SyncBN)for gradient optimization and integrate the Lovász-hinge loss function to leverage pixel dependency *** evaluations underscore the efficacy of our improved UPerNet,with results demonstrating Pixel Accuracy(PA)scores of 91.39%and 93.35%,Intersection over Union(IoU)values of 83.69%and 87.58%,Dice Coefficients of 91.12%and 93.38%,and Precision metrics of 90.85%and 93.41%across two distinct *** increment in detection accuracy was *** further practical applicability,we deploy semantic segmentation of rail surface defects,leveraging connected component processing techniques to distinguish varied defects within the same *** computing the actual defect length and area,our deep learning methodology presents results that offer intuitive insights for railway maintenance professionals.

关键词： Rail surface defects connected component analysis Transformer UPerNet

Covariant Prolongation Structure of Konno-Asai-Kakuhata Equation

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Communications in Theoretical Physics 2008年第9期50卷 565-567页

作者： XIE Tao li min-li School of Mathematical Sciences Capital Normal University Beijing 100048 China

Based upon the covariant prolongation structures theory, we construct the sl（2, R）×R（p） prolongation structure for Konno-Asai-Kakuhata equation. By taking two and one-dimensional prolongation spaces, we obtain the inverse scattering equations given by Konno et al. and the corresponding Riccati equation. The Baecklund transformations are also presented.

关键词： integrable equation covariant prolongation structure Baecklund transformation

Analytical Compliance Modeling of Serial Flexure-Based Compliant Mechanism Under Arbitrary Applied Load

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Chinese Journal of Mechanical Engineering 2017年第4期30卷 951-962页

作者： li-Ping Wang Yao Jiang Tie-min li Institute of Manufacturing Engineering Department of MechanicalTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Precision/Ultra-Precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China Institute of Instrument Science and Technology Department of Precision InstrumentTsinghua UniversityBeijing 100084China

Analytical compliance model is vital to the flexure- based compliant mechanism in its mechanical design and motion control. The matrix is a common and effective approach in the compliance modeling while it is not well developed for the closed-loop serial and parallel compliant mechanisms and is not applicable to the situation when the external loads are applied on the flexure mem- bers. Concise and explicit analytical compliance models of the serial flexure-based compliant mechanisms under arbitrary loads are derived by using the matrix method. An equivalent method is proposed to deal with the situation when the external loads are applied on the flexure mem- bers. The external loads are transformed to concentrated forces applied on the rigid links, which satisfy the equa- tions of static equilibrium and also guarantee that the deformations at the displacement output point remain unchanged. Then the matrix method can be still adopted for the compliance analysis of the compliant mechanism. Finally, several specific examples and an experimental testare given to verify the effectiveness of the compliance models and the force equivalent method. The research enriches the matrix method and provides concise analytical compliance models for the serial compliant mechanism.

关键词： Compliant mechanism Compliancemodeling Matrix method

MORPHOLOGY EVOLUTION OF POLY(St-co-BuA)/SIliCA NANOCOMPOSITE PARTICLES SYNTHESIZED BY EMULSION POLYMERIZATION

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Chinese Journal of Polymer Science 2006年第3期24卷 323-331页

作者： Hua li 周树学 Bo You li-min Wu Department of Materials Science The Advanced Coatings Research Center of China Educational Ministry Fudan University Shanghai 200433 China Faculty of Chemistry and Materials Science Hubei University Wuhan 430062 China

Poly（St-co-BuA）/silica nanocomposite latexes were synthesized via conventional emulsion polymerization in the presence of 3-（trimethoxysilyl）propyl methacrylate modified colloidal nano-silica. The effects of surface property, particle size and content of colloidal nano-silica as well as the concentrations of monomer and surfactant on the morphology of nanocomposite latex particles were investigated by transmission electron microscope （TEM） and scanning electron microscope （SEM） in detail. Various interesting morphologies such as grape-like, Chinese gooseberry-like, pomegranate-like and normal core-shell structures were observed. Droplet nucleation mechanism competing with micelle nucleation mechanism was proposed to explain the morphological evolution of the nanocomposite particles.

关键词： Morphology Colloidal nano-silica Nanocomposite particle Emulsion polymerization.

Observational analysis of the double-diffusive convection in the deep Canada Basin

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Acta Oceanologica Sinica 2015年第11期34卷 71-79页

作者： XIE lingling li mingming li min Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction (GLOD) Guangdong Ocean University

The Canada Basin （CB） is the largest sub-basin in the Arctic, with the deepest abyssal plain of 3 850 m. The double-diffusive process is the possible passage through which the geothermal energy affects the above isolated deep waters. With the temperature-salinity-pressure observations in 2003, 500-m-thick transition layers and lower 1 000-m-thick bottom homogenous layers were found below 2 400 m in the central deep CB. Staircases with downward-increasing temperature and salinity are prominent in the transition layers, suggesting the double- diffusive convection in deep CB. The interface of the stairs is about 10 m thick with 0.001-0.002℃ temperature difference, while the thicknesses of the homogenous layers in the steps decrease upward from about 60 to 20 m. The density ratio in the deep central CB is generally smaller than 2, indicating stronger double-diffusive convection than that in the upper ocean of 200-400 m. The heat flux through the deepest staircases in the deep CB varies between 0.014 and 0.031 W/m2, which is one-two orders smaller than the upper double-diffusive heat flux, but comparable to the estimates of geothermal heat flux.

关键词： double diffusion Canada Basin staircase heat flux water mass

Enhanced energy-absorbing and sound-absorbing capability of functionally graded and helicoidal lattice structures with triply periodic minimal surfaces

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International Journal of minerals,Metallurgy and Materials 2023年第10期30卷 1973-1985页

作者： Miao Zhao Zhendong li Jun Wei Chua Chong Heng lim Xinwei li Department of Mechanical Engineering National University of SingaporeSingapore 117411Singapore Chongqing Key Laboratory of Metal Additive Manufacturing(3D Printing) Chongqing UniversityChongqing 400044China Department of Mechanical Engineering Newcastle UniversitySingapore 567739Singapore

Lattice structures have drawn much attention in engineering applications due to their lightweight and multi-functional *** this work,a mathematical design approach for functionally graded(FG)and helicoidal lattice structures with triply periodic minimal surfaces is *** types of lattice structures including uniform,helicoidal,FG,and combined FG and helicoidal are fabricated by the additive manufacturing *** deformation behaviors,mechanical properties,energy absorption,and acoustic properties of lattice samples are thoroughly *** load-bearing capability of helicoidal lattice samples is gradually improved in the plateau stage,leading to the plateau stress and total energy absorption improved by over 26.9%and 21.2%compared to the uniform sample,*** phenomenon was attributed to the helicoidal design reduces the gap in unit cells and enhances fracture *** acoustic properties,the design of helicoidal reduces the resonance frequency and improves the peak of absorption coefficient,while the FG design mainly influences the peak of absorption *** broad range of frequency from 1000 to 6300 Hz,the maximum value of absorption coefficient is improved by18.6%-30%,and the number of points higher than 0.6 increased by 55.2%-61.7%by combining the FG and helicoidal *** study provides a novel strategy to simultaneously improve energy absorption and sound absorption properties by controlling the internal architecture of lattice structures.

关键词： additive manufacturing lattice structure triply periodic minimal surface energy absorption sound absorption