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2D SAXS/WAXD ANALYSIS OF PAN CARBON FIBER MICROSTRUCTURE IN ORGANIC/INORGANIC TRANSFORMATION

Chinese Journal of Polymer Science 2013年第5期31卷 823-832页

作者： Cai-zhen Zhu Xiao-lan Yu Xiao-fang liu Yun-zen Mao rui-gang liu 赵宁 Xiao-li Zhang 徐坚 Beijing National Laboratory for Molecular Sciences Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of Sciences ShenZhen Key Laboratory of Functional Polymer College of Chemistry and Chemical EngineeringShenzhen University College of Materials Science and Engineering Donghua University

Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction （2D SAXS/WAXD）. The SAXS results show that during pre-oxidation between 180 ℃ and 275 ℃, the volume content of microvoids increases with the temperature increasing, which may be one of reasons for the decrease of tensile strength ofpre-oxidized fibers. 253 ℃ was the critical transition temperature, the length, diameter, aspect ratio and orientation distribution of microvoids increased with temperature before this temperature and decreased after this temperature. After the high temperature carbonization, lots of spindly microvoids formed. WAXD patterns demonstrate that the crystallite size of PAN fibers first increased before 230 ℃ and then decreased with the increase of temperature during the pre-oxidation. The diffraction peak of PAN fibers at 2θ ≈ 17°almost disappeared at the end of pre- oxidation while the diffraction peak of aromatic structure at 2θ ≈ 25° appeared at 253 ℃. During carbonization, the peak intensity at 2θ ≈ 25° increased apparently due to the formation of graphite structure. The results obtained give a deep understanding of the microstrncture development in the PAN fibers during pre-oxidation and carbonization, which is important for the preparation of high performance carbon fibers.

关键词： Polyacrylonitrile Pre-oxidation Carbonization SAXS/WAXD Microstructure.

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Effect of austenitizing condition on mechanical properties,microstructure and precipitation behavior of AISI H13 steel

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Journal of Iron and Steel Research International 2024年第1期31卷 143-156页

作者： An-gang Ning Yang liu rui Gao Stephen Yue Ming-bo Wang Han-jie Guo College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Department of Mining and Materials Engineering McGill UniversityMontrealQCH3A 0C5Canada ASSAB Tooling Technology(Chongqing)Co. Ltd.Chongqing401120China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China

The effects of austenitizing temperature(1223,1303,and 1373 K)and holding time(1-1500 s)on the microstructure,mechanical properties,and precipitation behavior of the H13 hot work die steel were *** results indicate a softening phenomenon when H13 steel is austenitized at 1303 K beyond 900 s and 1373 K beyond 600 s,*** the sample held for 1200 s,the tensile strength is found capable of reaching up to 2.2 GPa when quenched from a temperature above 1303 ***,prior-austenite grain size increases with the increase in austenitizing *** kinetic behavior of the precipitates(mainly MC-type carbides)in H13 steel could be elaborated through the principles set forth by the Arrhenius and Avrami ***,the comprehensive strengthening of the H13 steel was discussed in *** results show that the activation energy of the transformed fraction of carbides is higher than that of the diffusion process for common alloying elements(Cr,V,Mo,and Ni)found in the *** suggests that it would be difficult for precipitates to dissolve into the matrix when H13 steel is austenitized at high *** the increasing austenitizing temperature,the precipitation fraction decreases,and the dislocation density *** dislocation strengthening is regarded as the dominant strengthening contributed to yield strength in as-quenched H13 steel.

关键词： H13 steel Austenitizing Mechanical property Precipitation behavior Comprehensive strengthening

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Development of a cell-permeable adenine-derived probe for capture of nucleotide-binding proteins in living cells

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Chinese Chemical Letters 2024年第3期35卷 243-246页

作者： Lihong liu rui Chen gang Xue Chenzhou Hao Weizhi Weng Zhengying Pan State Key Laboratory of Chemical Oncogenomics School of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China

Adenine is an essential building block of genetic material and a range of *** probes containing an adenine moiety have been used in kinase profiling studies in cell *** we report that adenine-derived small-molecule probes with an activated ester reactive group can covalently modify a conserved lysine residue of protein kinases and capture a number of nucleotide-binding proteins within living cells.

关键词： Adenine-derived probe Cell-permeable Lysine residue Protein kinases Nucleotide-binding proteins

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Structural evolution and high-temperature sensing performance of polymer-derived SiAlBCN ceramics

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Journal of Advanced Ceramics 2024年第4期13卷 478-485页

作者： Chao Ma Kun liu Pengfei Shao Daoyang Han Kang Wang Mengmeng Yang rui Zhao Hailong Wang rui Zhang gang Shao School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Zhongyuan Critical Metal Laboratory Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentZhengzhou UniversityZhengzhou 450002China

In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great ***,the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment,limiting their practical ***,polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis *** microstructure evolution,high temperature sensing properties,and stability were investigated in *** results show that the amorphous SiAlBCN phase grows more orderly and the size of the free carbon phase enlarges with the increasing *** defect concentration displays a decreasing ***,the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from roo temperature to 1100℃.The fabricated SiAlBCN temperature sensor possesses excellent stability,repeatability,and ***,SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200℃in a water/oxygen environment,which is attributed to their low corrosive rate constant(0.57 mg/(cm^(2)·h))and oxidative rate constant(3.43 mg^(2)/(cm^(4)·h)).Therefore,polymer-derived SiAlBCN ceramics as sensing materials,which possess outstanding stability and oxidation/corrosion resistance,have great potential for in-situ monitoring of extreme environmental temperatures in the future.

关键词： polymer-derived SiAlBCN ceramics temperature sensor harsh environments oxidation and corrosion resistance

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Ice-Induced Vibrational Response of Single-Pile Offshore Wind-Turbine Foundations

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Fluid Dynamics & Materials Processing 2024年第3期20卷 625-639页

作者： Zhoujie Zhu gang Wang Qingquan liu Guojun Wang rui Dong Dayong Zhang Department of Renewable Energy Engineering PowerChina Huadong Engineering Corporation LimitedHangzhou311122China School of Ocean Science and Technology Dalian University of TechnologyPanjin124221China Ningbo Institute of Dalian University of Technology Ningbo315000China

Important challenges must be addressed to make wind turbines sustainable renewable energy sources.A typical problem concerns the design of the *** the pile diameter is larger than that of the jacket platform,traditional mechanical models cannot be *** this study,relying on the seabed soil data of an offshore wind farm,the m-method and the equivalent embedded method are used to address the single-pile wind turbine foundation problem for different pile *** approach to determine the equivalent pile length is also proposed *** results provide evidence for the effectiveness and reliability of the model based on the equivalent embedded method.

关键词： Wind turbine ice-induced vibration dynamic response equivalent embedded method

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Construction of multifunctional lanthanum manganese mixed nanoparticles mediated by ionic liquids for selective aerobic oxidation of cyclohexane

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Rare Metals 2024年第5期43卷 2205-2221页

作者： Hao Li rui-rui Zhang Ke-Xin Li Shuang Wei Yu-Mei liu rui-Xia liu Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Selective oxidation of alkanes to produce highvalue chemicals is an essential strategy and means to realize efficient utilization of *** this work,a strategy of lanthanum manganese mixed metal oxides(LMMO)regulated via a facile ionic liquid(IL)-assisted hydrothermal method was proposed to construct the multifunctional catalysts,which exhibited excellent catalytic performance in the selective aerobic oxidation of *** 8.9%cyclohexane conversion with 90%KA oi(cyclohexanol and cyclohexanone)selectivity was achieved over the optimal LMMO catalyst under mild *** effects of anion type,carbon chain length and concentration of ILs on the structure and properties of catalysts were investigated through various characterizations,indicating the structure-directing and template effect of ILs on the multifunctional *** formation of self-assembled spherical nanoparticles followed the"dissolution-nucleation-proliferation"mechanism with the introduction of 1-butyl-3-methylimidazolium hydrogen sulfate,ascribing the synergistic effect between the microenvironment of ILs and the hydrothermal ***,the high reactive oxygen concentration redox capacity,and suitable basic sites of LMMO catalysts mediated by ILs enhance the activation of C-H bonds and molecular oxygen,simultaneously influencing the adsorption and desorption of the substrate.A comprehensive understanding of the high KA oil selectivity and radical reaction mechanism was elucidated based on in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and radical trapping *** recycling and regeneration experiments further illuminated that the removal of adsorbed cyclohexanone acting on the LMMO catalyst was the key to achieve high KA oil selectivity.

关键词： Ionic liquids Nanoparticle Multifunctional catalyst Cyclohexane oxidation

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Nano-engineered catalysts for high-performance oxygen reduction reaction

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Chinese Chemical Letters 2024年第10期35卷 510-516页

作者： Kunsong Hu Yulong Zhang Jiayi Zhu Jinhua Mai gang liu Manoj Krishna Sugumar Xinhua liu Feng Zhan rui Tan School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China Energy Innovation Centre Warwick Manufacture GroupUniversity of WarwickCoventry CV47ALUnited Kingdom School of Transportation Science and Engineering Beihang UniversityBeijing 100191China IDTECH(Suzhou)Co. Ltd.Suzhou 215217China College of Mechatronical and Electrical Engineering Hebei Agricultural UniversityBaoding 071001China

The efficient energy conversion of fuel cells is greatly constrained by the slow oxygen reduction reac tion(ORR)kinetics,which necessitates the use of highly active metal catalysts such as platinum(Pt).The critical challenge limiting large-scale usage of Pt is the capital cost that can be addressed through a pro totypical approach by embedding metal nanoparticles(NPs),e.g.,Pt NPs,in the conductive framework However,previously reported embedding approaches are sophisticated and suffer from limited yields leading to higher chemical process costs and remaining distant from commercial ***,we re port a facile,cost-effective and time-efficient structural tuning approach to synthesizing ultrafine Pt NP impregnated within a conductive and highly porous carbon framework via a microwave-assisted polyo reduction *** NPs with a uniform size of~2.27 nm can be successfully integrated within the pore of the carbon framework,enabling homogeneous *** from these highly dispersed and ultrafine Pt NPs,the electrochemical surface area(ECSA)is improved to 142.98 m^(2)/gPt,2.25 times highe than that of the commercial counterpart(63.52 m^(2)/gPt).Furthermore,our structurally optimized catalys composite features a remarkably catalytic activity with a high half-wave potential(E_(1/2))of 0.895 V and an improved mass activity(MA)of 0.2289 A/mgPt,2.39-fold improvement compared to the commercia *** addition,orthogonal experiments were designed to identify the key process parameter for fabricating Pt/C catalysts,offering insights for scaled-up and industrial production.

关键词： Fuel cells Oxygenreductionreaction Structural engineering Microwave method Ultrafine nanoparticles

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Elevated nitrogen and co-evolution history with competitors shape the invasion process of Galinsoga quadriradiata

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Journal of Plant Ecology 2024年第4期17卷 9-22页

作者： Wen-gang Zhang Xing-Jiang Song Laís Petri gang liu Xiao-Yan Chen rui-Ling liu Fang-Fang Huang Jia-Bin Zou Zhi-Hong Zhu College of Life Sciences Shaanxi Normal UniversityXi’an 710119China School for Environment and Sustainability University of MichiganAnn ArborMI 48109USA Research Center for UAV Remote Sensing Shaanxi Normal UniversityXi’an 710119China Changqing Teaching&Research Base of Ecology Shaanxi Normal UniversityXi’an 710119China Guangdong Provincial Key Laboratory of Silviculture Protection and UtilizationGuangdong Academy of ForestryGuangzhou 510520China

Invasive plants usually experience population differentiation as they expand from their initial invasive range to the ***,invasive plants usually encounter competitors which shared different co-evolutionary histories with *** factors may lead to varying responses of invasive plant populations to elevated nitrogen deposition during ***,this issue has received limited attention in prior *** address these challenges,we conducted a greenhouse experiment to investigate how population differentiation of Galinsoga quadriradiata interacts with the presence of various competitors in response to increased nitrogen *** types(new or old that shared short or long co-evolutionary history with the invader,respectively)were set to compete with the invasive central and edge populations under different nitrogen addition *** from the central population of ***,originating from the initial invasion range,showed greater total mass,reproduction and interspecific competitiveness compared with the edge *** addition improved growth and reproductive performance in both populations,and the central population had a stronger response compared with the edge *** performance of *** was inhibited more effectively by old competitors than new *** results indicate that population differentiation occurs in terms of growth and competitiveness during the range expansion of ***,with the central population exhibiting superior ***-evolutionary history with competitors is considered unfavorable for invasive plants in this *** results highlight the combined effects of population differentiation in invasive species and their co-evolution history with competitors in the context of global change factors.

关键词： Galinsoga quadriradiata central population edge population interspecific competition population differentiation elevated nitrogen

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Strong and tough chitin hydrogel constructed by dehydration and rehydration strategy

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Nano Research 2024年第9期17卷 8192-8199页

作者： rui-rui liu Li-Bo Mao Shu-Hong Yu Division of Nanomaterials and Chemistry Hefei National Research Center for Physical Sciences at the MicroscaleDepartment of ChemistryInstitute of Biomimetic Materials and ChemistryAnhui Engineering Laboratory of Biomimetic MaterialsUniversity of Science and Technology of ChinaHefei 230026China Institute of Innovative Materials Department of Materials Science and EngineeringDepartment of ChemistrySouthern University of Science and TechnologyShenzhen 518055China

As a renewable,biocompatible,biodegradable soft material,chitin hydrogels have better advantages in stability,antibacterial activity,antifouling,cost,immunogenicity,and so on than most polymer ***,compared with other widely used polymer hydrogels with high strength and toughness,the practical applications of chitin-based hydrogels have been limited by their weak mechanical properties,such as cartilage repair and meniscus ***,we present the design and fabrication of chitin hydrogels with excellent mechanical strength and toughness by a dehydration and rehydration *** sequential dehydration and rehydration processes,the crystalline domains in the chitin hydrogels can be properly *** optimized crystallinity,the elastic modulus of the chitin hydrogels exceeds all previously reported values,and the fracture toughness is even comparable to some synthetic polymer hydrogels,while maintaining a high-water-content of about 80 wt.%.At the same water content,the mechanical properties of the chitin hydrogels are positively correlated with the hydrogel crystallinity,which proves that the change of mechanical properties of hydrogels is not simply dependent on weight *** hydrogels can be further strengthened by incorporating other biopolymers that are intrinsically weak,which makes the hydrogels promising for applications in fields such as cartilage repair and meniscus ***,the hydrogels enable loading and release of water-soluble and poorly water-soluble *** highly extendable strengthening and toughening strategy of chitin and chitin-based biopolymer hydrogels paves the way for their widely applications.

关键词： chitin hydrogel crystallinity rehydration chemical transformation strong and tough

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Combustion characteristics of millimeter-sized aluminum particles in fluidized bed under various O_(2)/CO_(2)/H_(2)O atmospheres Author links open overlay panel

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Particuology 2024年第8期91卷 315-322页

作者： Jialing Zhou rui Zhang Dong liu Key Laboratory of Thermal Control of Electronic Equipment Ministry of Industry and Information TechnologyNanjing210094China Advanced Combustion Laboratory School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China

Aluminum is an attractive alternative fuel,but it burns very inefficiently due to the formation of a dense Al_(2)O_(3)layer which prevents O_(2)from diffusion to the surface of Al *** previous experiments,the combustion of millimeter-sized Al(mAl)particles in the fluidized bed has achieved a substantial increase in the combustion efficiency,but further improvements are still *** this study,the effects of reaction atmosphere on the fluidized combustion of mAl particles were *** experiments with different O_(2)/H_(2)O/CO_(2)concentrations were *** experimental results indicate that the combustion efficiency of mAl particles in fluidized bed increases as the mole fraction of O_(2),H_(2)O or CO_(2)increases,and the highest combustion efficiency can reach 38.7%.After the analysis of the oxide film on the surface of aluminum particles,it was found that it is easier to generate the unstableθ-Al_(2)O_(3)under CO_(2)atmosphere,and it is easier to generate the unstableγ-Al_(2)O_(3)andθ-Al_(2)O_(3)under H_(2)O *** unstable Al_(2)O_(3)film is more likely to be abraded in the fluidized bed,which leads to the effective improvement of the combustion efficiency.

关键词： Al combustion Fluidized bed Atmosphere Combustion efficiency

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