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Thermally Conductive,Healable Glass Fiber Cloth Reinforced Polymer Composite based onβ-Hydroxyester Bonds Crosslinked Epoxy with Improved Heat Resistance

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Chinese Journal of Polymer Science 2024年第5期42卷 643-654,I0009页

作者： Fang Chen xiao-Yan Pang Ze-Ping Zhang min-Zhi Rong ming-Qiu Zhang Key Laboratory for Polymeric Composite and Functional Materials of ministry of Education GD HPPC LabIGCMESchool of ChemistrySun Yat-sen UniversityGuangzhou510275China Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center Jieyang515200China

To simultaneously endow thermal conductivity,high glass transition temperature(Tg)and healing capability to glass fiber/epoxy(GFREP)composite,dynamic crosslinked epoxy resin bearing reversibleβ-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth(GFC@BNNSs).The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated ***,the GFC@BNNSs were impregnated with the mixture of lower concentration(3-glycidyloxypropyl)trimethoxysilane grafted BN micron sheets,3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride,which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical *** resultant GFREP composite containing less boron nitride particles(17.6 wt%)exhibited superior in-plane(3.29 W·m^(-1)·K^(-1))and through-plane(1.16 W·m^(-1)·K^(-1))thermal conductivities,as well as high Tg of 204℃(Tg of the unfilled epoxy=177℃).The reversible transesterification reaction enabled closure of interlaminar cracks within the composite,achieving decent healing efficiencies estimated by means of tensile strength(71.2%),electrical breakdown strength(83.6%)and thermal conductivity(69.1%).The present work overcame the disadvantages of conventional thermally conductive composites,and provided an efficient approach to prolong the life span of thermally conductive GFREP laminate for high-temperature resistant integrated circuit application.

关键词： Thermally conductive composites Boron nitride High-temperature resistance β-Hydroxyl ester bond Healing

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Injection of a Self-propelled Polymer into a Small Circular Cavity

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Chinese Journal of Polymer Science 2024年第6期42卷 886-894页

作者： Chao Wang Yan-Li Zhou xiao Yang Fan wu Meng-Bo Luo Department of Physics Taizhou UniversityTaizhou318000China Department of Physics Zhejiang UniversityHangzhou310027China

The injection of a polymer chain into a small circular cavity under tangential self-propelled force is studied by using Langevin dynamics *** indicate that the injection dynamics of the active polymer shows strong correlation with the polymer conformation inside the cavity depending on the polymer rigidity(k_(b)).The injection timeτvaries nonmonotonously with increasing k_(b),and reaches its minimum at k_(b)^(*).When k_(b) is small(k_(b)≪k_(b)^(*)),the polymer is nearly random coil in the cavity,and spends a long time at the final stage of the injection process due to the large repulsion between monomers inside the *** k_(b) is moderate(k_(b)∼k_(b)^(*)),the part of polymer inside the cavity forms spiral configuration under the tangential active force,and the whole polymer moves synchronously with a constant velocity during the injection process,leading to a small injection *** k_(b) is large(k_(b)≫k_(b)^(*)),the polymer is nearly straight at the initial stage of the injection process,and takes a long time to bend itself,leading to a large injection time.

关键词： Active Polymer Injection Dynamics Simulation

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Construction of biomimetic proton transport channels in metal-organic framework

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Chinese Chemical Letters 2024年第3期35卷 513-517页

作者： xiao-min Li Junchao Jia Danting Yang Jiali Jin Junkuo Gao School of Materials Science and Engineering Institute of Functional Porous MaterialsZhejiang Sci-Tech UniversityHangzhou 310018China Zhejiang Key Laboratory of Pathophysiology School of Public HealthSchool of MedicineNingbo UniversityNingbo 315211China

Construction of proton transport channels in metal-organic frameworks(MOFs)with simple synthesis processes,high proton conductivities and good performance stabilities has been of great interest for proton exchange membrane fuel cell(PEMFC).Herein,we mimic the proton transport behavior of amino acid residues in bacteriorhodopsin,select UiO-66-COOH as the host,glycine and aspartic acid as the functional guest molecules,and then functionalize the MOF framework with amino acids to obtain biomimetic proton transport *** strategy endows UiO-66-COOH-Asp a high proton conductivity of 1.19×10^(-2)S/cm at 70℃and 98%RH,excellent cycle stability of performances and performance durability,which can be comparable to the reported MOFs-based proton ***,the proton conduction mechanism in UiO-66-COOH-Asp is elaborated in detail due to its visual structure,which is also one of the advantages of adopting MOFs as research platform,making it possible to optimize the structure-activity relationship of advanced ***,this strategy has clear objectives and simple synthesis,which has made certain contributions to both theoretical research and future industrial production of proton conductors.

关键词： MOF Amino acids Biomimetic proton transport channels Synergistic effect Proton conduction mechanism

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New method to identify optimal discontinuity set number of rock tunnel excavation face orientation based on Fisher mixed evaluation

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Underground Space 2024年第4期17卷 300-319页

作者： Keshen Zhang Wei wu min Zhang Yongsheng Liu Yong Huang Baolin Chen College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of ministry of Education Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shudao Investment Group Co.Ltd Chengdu 610095China China Railway Tunnel Group Co.Ltd Guangzhou 511466China China Railway First Survey and Design Institute Group Co.Ltd Xi’an 710043China Zhejiang Institute of Communications Co.Ltd Hangzhou 310012China

Discontinuity is critical for strength,deformability,and permeability of rock *** information is one of the essential discontinuity characteristics and is usually accessed by orientation *** methods of identifying optimal discontinuity set numbers are usually achieved by clustering validity indexes,which mainly relies on the aggregation and dispersion of clusters and leads to the inaccuracy and instability of *** paper proposes a new method of Fisher mixed evaluation(FME)to identify optimal group numbers of rock mass discontinuity *** FME,orientation distribution is regarded as the superposition of Fisher mixed *** grouping results are identified by considering the fitting accuracy of Fisher mixed distributions,the probability monopoly and central location significance of independent Fisher centers.A Halley-Expectation-Maximization(EM)algorithm is derived to achieve an automatic fitting of Fisher mixed *** real rock discontinuity models combined with three orientation clustering algorithms are adopted for discontinuity *** clustering validity indexes are used to automatically identify optimal group numbers for *** results show that FME is more accurate and robust than the other clustering validity indexes in optimal discontinuity group number identification for different rock models and orientation clustering algorithms.

关键词： Rock mass discontinuity Orientation grouping Fisher mixed distribution 3D point cloud Stereo photogrammetry

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Frequency-dependent ferroelectric and electrocaloric properties in barium titanate-based ceramics based on Maxwell relations

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Journal of Advanced Dielectrics 2024年第2期14卷 54-62页

作者： Wanting Shu Hong Li Yanli Huang Cong Lin xiao wu min Gao Tengfei Lin Chunlin Zhao College of Materials Science and Engineering Fuzhou University Fuzhou 350108P.R.China College of Photonic and Electronic Engineering Fujian Normal University Fuzhou 350117P.R.China

In this work,the frequency dependence of ferroelectric and electrocaloric properties in barium titanate-based ceramics was studied based on Maxwell *** is found that the maximum and remnant polarization will decrease while the coercive field increases a lot with rising frequency from 0.1 to 10 Hz,indicating that polarization rotation and domain switching become difficult at high *** electrocaloric properties show the different frequency dependence at different phase *** entropy change(ΔS)and adiabatic temperature change(ΔT)are similar around/above Curie temperature(TCT,showing tiny frequency ***,ΔS andΔT display the obvious frequency dependence below T_(C),especially in the orthorhombic–tetragonal phase-transition region with a stable ferroelectric phase,and this frequency dependence becomes more obvious under a low-electric *** is also found that increasing the frequency can weaken the electric field dependence of electrocaloric *** work gives a general profile of frequency dependence for electrocaloric properties in ferroelectric ceramics.

关键词： Electrocaloric properties ferroelectric ceramics barium titanate frequency dependence

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CCDC181 is required for sperm flagellum biogenesis and male fertility in mice

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Zoological Research 2024年第5期45卷 1061-1072页

作者： Xiang-Jun Zhang xiao-Ning Hou Jian-Teng Zhou Bao-Lu Shi Jing-Wei Ye Meng-Lei Yang xiao-Hua Jiang Bo Xu Li-min wu Qing-Hua Shi Division of Reproduction and Genetics First Affiliated Hospital of University of Science and Technology of China(USTC)Hefei National Laboratory for Physical Sciences at MicroscaleSchool of Basic Medical SciencesDivision of Life Sciences and MedicineBiomedical Sciences and Health Laboratory of Anhui ProvinceInstitute of Health and MedicineHefei Comprehensive National Science CenterUniversity of Science and Technology of ChinaHefeiAnhui 230001China

The structural integrity of the sperm flagellum is essential for proper sperm *** defects can result in male infertility,yet the precise mechanisms underlying this relationship are not fully ***181,a coiled-coil domain-containing protein,is known to localize on sperm flagella and at the basal regions of motile *** this knowledge,the specific functions of CCDC181 in flagellum biogenesis remain *** this study,Ccdc181 knockout mice were *** absence of CCDC181 led to defective sperm head shaping and flagellum ***,the Ccdc181 knockout mice exhibited extremely low sperm counts,grossly aberrant sperm morphologies,markedly diminished sperm motility,and typical multiple morphological abnormalities of the flagella(MMAF).Additionally,an interaction between CCDC181 and the MMAF-related protein LRRC46 was identified,with CCDC181 regulating the localization of LRRC46 within sperm *** findings suggest that CCDC181 plays a crucial role in both manchette formation and sperm flagellum biogenesis.

关键词： Male infertility CCDC181 MMAF Spermiogenesis Flagellum biogenesis

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高聚合物膜蒸发器冷凝表面液滴润湿状态研究

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工程热物理学报 2016年第11期37卷 2447-2451页

作者：朱毅吴晓敏褚福强清华大学热能工程系热科学与动力工程教育部重点实验室北京市CO2资源利用与减排技术重点实验室北京100084

为了增强高聚合物膜蒸发器中换热面的导热性能,通常的做法是减小膜的厚度,而低膜厚条件下换热面上冷凝液滴的润湿状态通常只由表面一级结构(槽状)决定。本文在研究已有润湿状态区间的前提下,通过分析Cassie-Baxter方程和Wenzel方程在描... 详细信息

为了增强高聚合物膜蒸发器中换热面的导热性能,通常的做法是减小膜的厚度,而低膜厚条件下换热面上冷凝液滴的润湿状态通常只由表面一级结构(槽状)决定。本文在研究已有润湿状态区间的前提下,通过分析Cassie-Baxter方程和Wenzel方程在描述槽状聚合物表面液滴润湿状态时存在的问题,进一步细分了表面润湿状态区间,并分区间提出了相应的状态描述方程,为研究蒸发器换热面上液滴的冷凝形态及进行换热面设计提供了依据。

关键词：高聚合物膜蒸发器冷凝表面润湿状态槽状表面

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Surface tension of single suspended aerosol microdroplets

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Chinese Chemical Letters 2024年第4期35卷 520-524页

作者： Yukai Tong Zhijun wu Bo Zhou min Hu Anpei Ye Key Laboratory for the Physics and Chemistry of Nanodevices School of ElectronicsPeking UniversityBeijing 100871China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

The surface tension of troposphere aerosols can significantly influence their atmospheric processes and key properties, particularly on the morphology, the phase transition, the activation as cloud condensation nuclei, and the gas-particle partitioning. However, directly measuring the surface tension of single ambient aerosol is quite challenging, due to the limitations of their picolitre volumes and thermal motion. Here, we developed a dual laser tweezers Raman spectroscopy(DLT-RS) system to directly sense the surface tension of single airborne microdroplets(PM10particles). A pair of aerosol droplets were trapped and driven to coalesce by the laser tweezers. Meanwhile, the backscattering light intensity and brightfield images during the coalescence process were recorded to characterize the aerosol surface tension. A remarkable advantage of directly sensing aerosol surface tension is that the solutes in aerosols are often supersaturated, which is common in atmospheric aerosols but almost unavailable in bulk *** experimentally measured the surface tension of aerosols composed of nitrates or oxalic acid/nitrate mixture. Besides, the variation of surface tension during aerosol aging process was also explored, which brings possible implications on the surface evolution of actual ambient aerosol during their atmospheric lifetime.

关键词： Surface tension Droplet coalescence Single aerosol Laser tweezers Aerosol aging

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微观结构尺度对液滴润湿状态的影响

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工程热物理学报 2019年第11期40卷 2632-2636页

作者：朱毅吴晓敏褚福强清华大学能源与动力工程系热科学与动力工程教育部重点实验室北京市CO_2资源利用与减排技术重点实验室

在分析表面微观特征对液滴润湿状态的影响时,尺度效应是无法绕过的前提条件和分析基础。本文以矩形微结构表面液滴为研究对象,通过数值模拟,得到了给定微结构表面液滴在不同液滴半径与矩形微结构宽度比例下的润湿状态。此外,本文还模拟... 详细信息

在分析表面微观特征对液滴润湿状态的影响时,尺度效应是无法绕过的前提条件和分析基础。本文以矩形微结构表面液滴为研究对象,通过数值模拟,得到了给定微结构表面液滴在不同液滴半径与矩形微结构宽度比例下的润湿状态。此外,本文还模拟得到了液滴完全浸润矩形微结构的临界接触角及其相对于微结构尺寸的变化规律。结果表明,液滴半径与微结构宽度比越小,液滴下气液界面开始浸润微结构时的临界接触角越大,无重力条件下表面液滴下气液界面的稳定性越差。若重力不可忽略,则液滴半径与微结构宽度比越大,重力的影响越大,表面液滴下气液界面的稳定性越差。

关键词：微观结构尺度液滴润湿状态

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Asymptotic normality of error density estimator in stationary and explosive autoregressive models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 140-158页

作者： wu Shi-peng YANG Wen-zhi GAO min HU Shu-he School of Mathematical Sciences&School of Big Data and Statistics Anhui UniversityHefei 230601China School of Statistics Shanxi University of Finance and EconomicsTaiyuan030006China

In this paper,we consider the limit distribution of the error density function estima-tor in the rst-order autoregressive models with negatively associated and positively associated random *** mild regularity assumptions,some asymptotic normality results of the residual density estimator are obtained when the autoregressive models are stationary process and explosive *** order to illustrate these results,some simulations such as con dence intervals and mean integrated square errors are provided in this *** shows that the residual density estimator can replace the density\estimator"which contains errors.

关键词： explosive autoregressive models residual density estimator asymptotic distribution association sequence

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