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Microstructure, mechanical properties and magnetic properties of FeCoNiCuTiSix high-entropy alloys 认领
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作者 QU HuaiZhi GONG MingLong +4 位作者 LIU FengFang GAO BingYu BAI Jing GAO QiuZhi LI Song 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2020年第3期459-466,共8页
The microstructure, mechanical properties and magnetic properties of FeCoNiCuTiSi_x(x=0, 0.05, 0.1, 0.2, 0.4 and 0.5) highentropy alloys were studied in detail in the present paper. The crystal structure changes from ... The microstructure, mechanical properties and magnetic properties of FeCoNiCuTiSi_x(x=0, 0.05, 0.1, 0.2, 0.4 and 0.5) highentropy alloys were studied in detail in the present paper. The crystal structure changes from FCC+Laves to FCC+BCC+Laves phases, as the Si content increases. Cu is more segregated with the increase in Si content, which can be explained from a thermodynamic point of view. The FeCoNiCuTi high-entropy alloy has good compression mechanical properties, and the fracture strength, fracture strain, and Vickers hardness are 1584.2 MPa, 3.3% and 483.2 HV, respectively. However, the plasticity of the alloy decreases slightly as the Si content increases. The highest fracture strength obtained in this study is 1841.7 MPa at x=0.1. 展开更多
关键词 high-entropy alloys MICROSTRUCTURE PROPERTIES mechanical PROPERTIES MAGNETIC PROPERTIES
Synergistic effect of hybrid Himalayan Nettle/Bauhinia-vahlii fibers on physico-mechanical and sliding wear properties of epoxy composites 认领
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作者 Sandeep Kumar KKSMer +1 位作者 Brijesh Gangil Vinay Kumar Patel 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第4期762-776,共15页
The cellulosic bast fibers are recognized as a justifiable and biodegradable substitute for producing moderate strength polymer composite materials because of their characteristics of renewability,ecofriendliness,and ... The cellulosic bast fibers are recognized as a justifiable and biodegradable substitute for producing moderate strength polymer composite materials because of their characteristics of renewability,ecofriendliness,and higher specific strength.Hence the aim of this research work is to fabricate Himalayan bast fibers(Nettle fiber(NF)/bauhinia vahlii fiber(BF)) based mono/hybrid epoxy composites at varying weight percentage of 2-6 wt% and evaluate the physical(void fraction and water absorption),mechanical(tensile strength,flexural strength,hardness) and sliding wear properties of as-fabricated composites.The 6 wt% NBF reinforced composites exhibited higher mechanical properties as compared to NF and BF composites with tensile strength of 34.04 MPa,flexural strength of 42.45 MPa,and hardness of 37.01 Hv respectively.The influence of various control factors(sliding velocity,NF/BF/NBF contents,normal load and sliding distance) on specific sliding wear rate of composites was evaluated by Taguchi(three factors at three levels) experimental design and the percentage contribution of these selected parameters on sliding wear performance was examined by Analysis of variance(ANOVA).The sliding wear property of as-developed composites was found to be greatly influenced by sliding velocity and the wear resistance was observed to be improved with the NF/BF/NBF contents.The wear mechanism of the as-fabricated composites has been elucidated by scanning electron microscopy analysis.The research outcomes demonstrated that the hybridization of Bauhinia vahlii fiber with Nettle fiber led to improve the mechanical and wear properties of epoxy composites. 展开更多
关键词 Natural fiber Physical properties Mechanical properties Wear properties Taguchi analysis
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Theoretical investigation on the stability, mechanical and thermal properties of the newly discovered MAB phase Cr4AlB4 认领
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作者 Fu-Zhi Dai Haiming Zhang +1 位作者 Huimin Xiang Yanchun Zhou 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第4期161-166,共6页
The nanolaminated MAB phases have attracted great research interests in recent years due to their similarities to MAX phases,which display both metallic and ceramic-like properties.In the present work,a newly discover... The nanolaminated MAB phases have attracted great research interests in recent years due to their similarities to MAX phases,which display both metallic and ceramic-like properties.In the present work,a newly discovered MAB phase Cr4AlB4 was investigated by first principles calculations.Energy evaluations indicate that Cr4AlB4 can be synthetized in Al lean condition,which can further transform to Cr2AlB2 in Al rich condition.The full set of elastic properties and their dependences on temperature,ideal strengths under different tensile and shear deformations,and thermal expansions of Cr4AlB4 were predicted.The results reveal that the properties of Cr4AlB4 are dominated by the layered crystal structure and weak bonding nature between Al and Cr2B2 layers,including low elastic stiffness and large thermal expansion along[010]direction(the stacking direction of Al and Cr2B2 layers),low shear resistances in(010)plane,and preferentially cleavage along and/or shear in(010)plane.Therefore,it suggests that Cr4AlB4 displays similar mechanical properties to MAX phases,including readily machinable,thermal shock resistant,and damage tolerant.In combination with the fact that Cr,Al and B all can form dense oxides to protect the material from further oxidation,Cr4AlB4 is regarded as a promising high temperature ceramic. 展开更多
关键词 MAB PHASE Cr4AlB4 FIRST-PRINCIPLES Mechanical PROPERTIES Thermal PROPERTIES
Ultralight three-dimensional,carbon-based nanocomposites for thermal energy storage 认领
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作者 Oluwafunmilola Ola Yu Chen +3 位作者 Qijian Niu Yongde Xia Tapas Mallick Yanqiu Zhu 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第1期70-78,共9页
Polymer based nanocomposites consisting of elastic three-dimensional(3 D)carbon foam(CF),paraffin wax and graphene nanoplatelets(GNPs)have been created and evaluated for thermal energy storage.The ultralight,highly po... Polymer based nanocomposites consisting of elastic three-dimensional(3 D)carbon foam(CF),paraffin wax and graphene nanoplatelets(GNPs)have been created and evaluated for thermal energy storage.The ultralight,highly porous(~98.6%porosity),and flexible CFs with densities of2.84-5.26 mg/cm^3 have been used as the backbone skeleton to accommodate phase change wax and nanoscale thermal conductive enhancer,GNP.Low level of defects and the ordered sp2 configuration allow the resulting CFs to exhibit excellent cyclic compressive behavior at strains up to 95%,while retaining part of their elastic properties even after 100 cycles of testing.By dispersing the highly conductive GNP nanofillers in paraffin wax and infiltrating them into the flexible CFs,the resultant nanocomposites were observed to possess enhanced overall thermal conductivity up to 0.76 W/(m K),representing an impressive improvement of226%,which is highly desirable for thermal engineering. 展开更多
关键词 NANOCOMPOSITES Foam THERMAL PROPERTIES COMPRESSIVE PROPERTIES
Combustion synthesis,structural,magnetic and dielectric properties of Gd3+-doped lead molybdato-tungstates 认领
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作者 T.GRON M.MACIEJKOWICZ +6 位作者 E.TOMASZEWIC M.GUZIK M.OBOZ B.SAWICKI S.PAWLUS A.NOWOK Z.KUKULA 《先进陶瓷:英文版》 SCIE CSCD 2020年第2期255-268,共14页
Gd^3+-doped lead molybdato–tungstates with the chemical formula of Pb1–3x􀀀xGd2x(MoO4)1–3x(WO4)3x(where x=0.0455,0.0839,0.1430,corresponding to 9.53,18.32,33.37 mol%of Gd^3+,respectively,as well as􀀀... Gd^3+-doped lead molybdato–tungstates with the chemical formula of Pb1–3x􀀀xGd2x(MoO4)1–3x(WO4)3x(where x=0.0455,0.0839,0.1430,corresponding to 9.53,18.32,33.37 mol%of Gd^3+,respectively,as well as􀀀denotes cationic vacancies)were successfully synthesized via combustion route.The XRD and SEM results confirmed the formation of single-phase,tetragonal scheelite-type materials(space group I41/a)with the uniform,spherical and oval grains ranging from 5 to 20mm.Individual grains are strongly agglomerated into big clusters with the size even above 50mm.The magnetic measurements as well as the Brillouin fitting procedure showed paramagnetic state with characteristic superparamagnetic-like behaviour and the short-range ferromagnetic interactions.The electrical and broadband dielectric spectroscopy studies revealed insulating properties with the residual electrical n-type conduction of 2×10^–9 S/m and low energy loss(tand»0.01)below 300 K.Dielectric analysis showed that no dipole relaxation processes in the Gd^3+-doped materials were observed.A fit of dielectric loss spectra of Gd^3+-doped samples by sum of the conductivity and the Havriliak–Negami,Cole–Cole,and Cole–Davidson functions confirmed this effect. 展开更多
关键词 SCHEELITE Gd^3+-substituted PbMoO4 combustion solid solution magnetic properties dielectric properties
Mechanical properties and frictional resistance of Al composites reinforced with Ti3C2Tx MXene 认领
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作者 Jie Hu Shibo Li +3 位作者 Jing Zhang Qiuying Chang Wenbo Yu Yang Zhou 《中国化学快报:英文版》 SCIE CAS CSCD 2020年第4期996-999,共4页
Two-dimensional(2D)Ti3C2Tx MXene is an attractive additive not only used in base oil due to its low friction coefficient,but also used in composites due to its high aspect ratio and rich surface functional groups.So f... Two-dimensional(2D)Ti3C2Tx MXene is an attractive additive not only used in base oil due to its low friction coefficient,but also used in composites due to its high aspect ratio and rich surface functional groups.So far there has been intense research into polymer matrix composites reinforced with Ti3C2Tx,Here we report on the use of 2D Ti3C2Tx to enhance the mechanical and frictional properties of Al matrix composites.Ti3C2Tx/Al composites were designed and prepared by pre s sureless sintering followed by hot extrusion technique.The prepared composites exhibit a homogeneous distribution of Ti3C2Tx.The Vickers hardness and the tensile strength continuously increase with increasing Ti3C2Tx content.A hardness of 0.52 GPa and a tensile strength of 148 MPa were achieved in the 3 wt%Ti3C2Tx/Al composite.The frictional properties of pure Al and the Ti3C2Tx/Al composite were comparably studied under dry sliding.A low friction coefficient of 0.2,twice lower than that of pure Al,was achieved in the 3 wt%Ti3C2Tx/Al composite.Ti3C2Tx acting as a solid lubricant reduces the abrasive wear in the composite,improving the frictional properties of Al matrix composites. 展开更多
关键词 Ti3C2Tx Mxene Al composites MICROSTRUCTURE Mechanical properties Frictional properties
Syntheses,Crystal Structures,Luminescent and Magnetic Properties of Three Ni(Ⅱ),Zn(Ⅱ) and Cd(Ⅱ) Coordination Polymers Based on an Ether-bridged Tetracarboxylic Acid 认领
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作者 黎彧 陈泳璇 +2 位作者 赵振宇 邹训重 冯安生 《结构化学》 SCIE CAS CSCD 2020年第5期967-977,共11页
Two 1D and one 3D coordination polymers,namely[Ni2(μ3-deta)(H2 biim)3(H2O)2]n(1),{[Zn2(μ4-deta)(Phen)2(H2O)]·H2O}n(2)and[Cd2(μ6-deta)(Phen)2(H2O)]n(3),have been constructed hydrothermally using H4deta(H4deta=2... Two 1D and one 3D coordination polymers,namely[Ni2(μ3-deta)(H2 biim)3(H2O)2]n(1),{[Zn2(μ4-deta)(Phen)2(H2O)]·H2O}n(2)and[Cd2(μ6-deta)(Phen)2(H2O)]n(3),have been constructed hydrothermally using H4deta(H4deta=2,3,3’,4’-diphenyl ether tetracarboxylic acid),H2 biim(H2 biim=2,2’-biimidazole),phen(phen=1,10-phenanthroline),and nickel,zinc or cadmium chlorides at 160℃.The products were isolated as stable crystalline solids and characterized by IR spectra,elemental analyses,thermogravimetric analyses(TGA)and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group■.Compounds 1 and 2 disclose a 1D chain structure.Compound 3 features a 3D framework.The structural diversity of compounds 1~3 is driven by the metal(Ⅱ)node and the type of supporting ligand.Magnetic studies for compound 1 demonstrate an antiferromagnetic coupling between the adjacent Ni(Ⅱ)centers.The luminescence behavior of compounds 2 and 3 was also investigated. 展开更多
关键词 coordination polymer tetracarboxylic acid magnetic properties luminescent properties
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Effects of Surface Modifications on the Mechanical Properties of Reinforced Pineapple Leaf Fibre Polypropylene Composites 认领
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作者 Samuel Wadzani Gadzama O. K. Sunmonu +1 位作者 U. S. Isiaku Abdullahi Danladi 《化学工程与科学期刊(英文)》 2020年第1期24-39,共16页
Pineapple Leaf Fibre (PALF) is one of the natural fibres that have high potential in the industry. Natural fibres have become the main alternative source for reinforced polymer composites. The objective of this study ... Pineapple Leaf Fibre (PALF) is one of the natural fibres that have high potential in the industry. Natural fibres have become the main alternative source for reinforced polymer composites. The objective of this study is to observe the effect of chemical treatments using Sodium Hydroxide (NaOH) solution, Zinc chloride, Acetic Anhydride and Nitric acid on the mechanical properties of pineapple leaf fibre reinforced polypropylene composites. The tensile test was conducted by using the ASTM D638-10 to obtain the tensile strength (TS) and Young’s modulus (YM), Flexural properties were conducted to determine the flexural strength (FS) and flexural modulus (FM) of the reinforced composites using the ASTM D256-10 method, and impact test was conducted to determine the impact strength (IS) of the reinforced composites using the Izod ASTM D790-17 method. From the results obtained, the composites with surface modified PALF fillers show enhanced mechanical properties over the untreated PALF fillers in this order;for TS untreated composite C3H6O3 3. For YM untreated composite 3 C3H6O3 3 3H6O3. For FM, untreated reinforced PALF/PP composites C3H6O3 3. For IS, the untreated reinforced PALF/PP composites 3 C3H6O3. SEM analysis was carried out on the PALF before the compounding to analyze the effect of the surface modification agents. 展开更多
关键词 SURFACE Modifications PROPERTIES
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Theoretical prediction on thermal and mechanical properties of high entropy(Zr(0.2)Hf(0.2)Ti(0.2)Nb(0.2)Ta(0.2))C by deep learning potential 认领
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作者 Fu-Zhi Dai Bo Wen +2 位作者 Yinjie Sun Huimin Xiang Yanchun Zhou 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第8期168-174,共7页
High entropy materials(HEMs, e.g. high entropy alloys, high entropy ceramics) have gained increasing interests due to the possibility that they can provide challenge properties unattainable by traditional materials. T... High entropy materials(HEMs, e.g. high entropy alloys, high entropy ceramics) have gained increasing interests due to the possibility that they can provide challenge properties unattainable by traditional materials. Though a large number of HEMs have emerged, there is still in lack of theoretical predictions and simulations on HEMs, which is probably caused by the chemical complexity of HEMs. In this work,we demonstrate that the machine learning potentials developed in recent years can overcome the complexity of HEMs, and serve as powerful theoretical tools to simulate HEMs. A deep learning potential(DLP) for high entropy(Zr(0.2) Hf(0.2) Ti(0.2) Nb(0.2) Ta(0.2))C is fitted with the prediction error in energy and force being 9.4 me V/atom and 217 me V/?, respectively. The reliability and generality of the DLP are affirmed,since it can accurately predict lattice parameters and elastic constants of mono-phase carbides TMC(TM = Ti, Zr, Hf, Nb and Ta). Lattice constants(increase from 4.5707 ? to 4.6727 ?), thermal expansion coefficients(increase from 7.85×10-6 K~(-1) to 10.58×10-6 K~(-1)), phonon thermal conductivities(decrease from 2.02 W·m-1·K~(-1) to 0.95 W·m-1·K~(-1)), and elastic properties of high entropy(Zr(0.2) Hf(0.2) Ti(0.2) Nb(0.2) Ta(0.2))C in temperature ranging from 0°C to 2400°C are predicted by molecular dynamics simulations. The predicted room temperature properties agree well with experimental measurements, indicating the high accuracy of the DLP. With introducing of machine learning potentials, many problems that are intractable by traditional methods can be handled now. It is hopeful that deep insight into HEMs can be obtained in the future by such powerful methods. 展开更多
关键词 High entropy ceramics Machine learning potential Thermal properties Mechanical properties Molecular dynamics Simulation
Application of Design of Experiments for AlloyDevelopment of an Aluminum Copper Casting Alloy 认领
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作者 Franziska Kr?ger Babette Tonn 《材料科学与工程:中英文A版》 2020年第1期6-23,共18页
Design of experiments (DoE) based on a linear regression model was used to develop an Aluminum Copper-based casting alloy. The main objectives of the development were the achievement of (1) a high strength at elevated... Design of experiments (DoE) based on a linear regression model was used to develop an Aluminum Copper-based casting alloy. The main objectives of the development were the achievement of (1) a high strength at elevated temperatures with (2) a low hot tearing tendency. Within the DoE, 17 different chemical compositions of the newly developed alloy AlCuMnCo(Ni) were cast, tested regarding hot tearing tendency and characterized in tensile tests up to 300 °C. Test results showed that the AlCuMnCo(Ni)-alloys from the DoE have high mechanical properties from ambient temperature up to 300 °C and thus feature a high thermal stability. It was found that the alloying elements Cu and Co increase the yield strength whereas Mn and Ni tend to increase the attainable elongation. Furthermore, some of the alloys showed no or a very low tendency to hot tearing a remarkable feature for Al-Cu alloys which are otherwise highly susceptible to hot tearing. The regression model that was developed from the test results fulfils a set of quality criteria and is therefore expected to provide reliable predictions. The predictive ability of the model was validated by casting and testing a sweet spot alloy. Results show that the model is sufficient for predicting the mechanical properties from ambient temperature to 250 °C. Furthermore, the sweet spot alloy surpasses the reference alloy AlCuNiCoSbZr (RR30) in its mechanical properties up to 250 °C. It was shown that by applying design of experiments, time and effort for an alloy development can effectively be reduced and simultaneously a high degree of information density about the alloying system considered is generated. 展开更多
关键词 Optimization ELEVATED temperature PROPERTIES mechanical PROPERTIES HOT TEARING AlCuMnCo(Ni).
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Influence of travel speed on microstructure and mechanical properties of wire + arc additively manufactured 2219 aluminum alloy 认领
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作者 Yinghui Zhou Xin Lin +3 位作者 Nan Kang Weidong Huang Jiang Wang Zhennan Wang 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第2期143-153,共11页
Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum alloy.The influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties w... Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum alloy.The influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties were investigated.The results indicated that as the electric arc TS increased,the size and the volume fraction of equiaxed grain decreased.The high arc TS during WAAM also promoted the precipitation of theθ(Al2Cu)phase.The volume fractions ofθ’’andθ’phases reached maximum values when TS is 350 and 250 mm/min,respectively.The thermal cycle facilitated the precipitation of theθ’phase.In addition,the micro-hardness and tensile strength of the alloy were analyzed,and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength(273.5 MPa)and yield strength(182.9 MPa)compared to those fabricated at 250 mm/min. 展开更多
关键词 Wire+arc ADDITIVE MANUFACTURING 2219 ALUMINUM alloy MICROSTRUCTURE Mechanical properties
Mechanical properties and wear resistance of ultrafine bainitic steel under low austempering temperature 认领
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作者 Wei Liu You-hui Jiang +3 位作者 Hui Guo Yue Zhang Ai-min Zhao Yao Huang 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2020年第4期483-493,共11页
The mechanical properties and wear resistance of the ultrafine bainitic steel austempered at various temperatures were investigated.Scanning electron microscopy(SEM)and X-ray diffraction were used to analyze the micro... The mechanical properties and wear resistance of the ultrafine bainitic steel austempered at various temperatures were investigated.Scanning electron microscopy(SEM)and X-ray diffraction were used to analyze the microstructure.The worn surfaces were observed via laser scanning confocal microscopy and SEM.Results indicated that,under low austempering temperatures,the mechanical properties differed,and the wear resistance remained basically unchanged.The tensile strength of the samples was above 1800 MPa,but only one sample austempered at 230°C had an elongation of more than 10%.The weight loss of samples was approximately linear with the cycles of wear and nonlinear with the loads.The samples showed little difference in wear resistance at different isothermal temperatures,whereas the thickness of their deformed layers varied greatly.The results are related to the initial hardness of the sample and the stability of the retained austenite.Meanwhile,the experimental results showed that the effect of austempering temperature on the wear resistance of ultrafine bainitic steel can be neglected under low applied loads and low austempering temperature. 展开更多
关键词 bainitic steel mechanical properties WEAR resistance AUSTEMPERING temperature
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Preparation of Photochromic Waterborne Polyurethane Films:Effect of Spiropyran Concentration on Photochromic Properties 认领
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作者 鲍利红 王世贤 《东华大学学报:英文版》 EI CAS 2020年第1期28-34,共7页
Incorporation of photochromic compounds to the polymer through chemical bonding will result in an enhancement of photoactivity and stabilization of optical properties.Here,spiropyran(SP)was introduced into polyurethan... Incorporation of photochromic compounds to the polymer through chemical bonding will result in an enhancement of photoactivity and stabilization of optical properties.Here,spiropyran(SP)was introduced into polyurethane(PU)through semi-continuous emulsion copolymerization to get waterborne polyurethane dispersion(SPU).Studies on photochromic properties by UV-vis technique demonstrated the absorption intensity increased with the increasing of SP concentration and the colorless film turned to purple under UV irradiation.The kinetics for ring-opening and ring-closing reaction against SP were both first order,but the rate constants decreased with the increasing of SP concentration.The prepared SPU films showed reasonable photostability and photoreversibility according to the convenient test methods under UV-vis irradiation.Temperature dependence studies demonstrated that the photobleaching rate increased at higher temperatures with the same SP concentration.The chemical combination between SP and isocyanate(NCO)end group of polyurethane was confirmed through swelling experiments.Morphology studies were conducted by scanning electron microscope(SEM)micrographs and showed good compatibility between SP and PU. 展开更多
关键词 SPIROPYRAN CONCENTRATION WATERBORNE POLYURETHANE film PHOTOCHROMIC properties KINETICS
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Mineralogical characteristics and photocatalytic properties of natural sphalerite from China 认领
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作者 Can Shen Xiangping Gu +5 位作者 Bin Yang Dexian Zhang Zhilin Wang Zhengxiang Shu Jeffrey Dick Anhuai Lu 《环境科学学报:英文版》 SCIE EI CAS CSCD 2020年第3期156-166,共11页
Different natural sphalerites have a range of photocatalytic properties that can potentially be exploited for environmental remediation purposes.To develop value in the exploitation of sphalerite,samples were collecte... Different natural sphalerites have a range of photocatalytic properties that can potentially be exploited for environmental remediation purposes.To develop value in the exploitation of sphalerite,samples were collected from 19 ore deposits in China and characterized for their mineralogical and photocatalytic properties.X-ray diffraction(XRD) and electron probe micro analysis(EPMA) measurements indicated that all the natural sphalerites from various localities crystallized in cubic phases with various chemical compositions.The substitution of Fe for Zn ranged from 0.235% to 14.826% by weight,Mn from 0.004% to4.868%,Cu from 0.009% to 5.529% and Cd from 0.133% to 1.576%.As Fe became more abundant,the color of natural sphalerite darkened,becoming almost black;and higher Fe content was associated with stronger visible light absorption.Photoluminescence spectra showed emission mainly related to S-vacancies and progressively decreasing fluorescence intensity with increasing Fe content.Tests of the photocatalytic degradation of methyl orange indicated that the sample with the highest Cd content but moderate Fe content had the highest photocatalytic activity.Specifically,the degradation of Methyl Orange(30 mg/L)attained 82.11% efficiency under visible light irradiation for 4 hr of natural sphalerite with4.262% Fe and 1.576% Cd.Overall,the Fe content in sphalerite was found to contribute to the visible light absorption ability and the recombination rate of photo-generated electrons and holes,while substitution by Cd was observed to have a greater effect on the photocatalytic properties.These findings provide a scientific basis for the profitable utilization of base metal resources like sphalerite. 展开更多
关键词 NATURAL SPHALERITE MINERALOGICAL properties Band gap PHOTODEGRADATION of Methyl ORANGE
Effect of graphene oxide and reduced graphene oxide nanosheets on the microstructure and mechanical properties of mild steel jointing by flux-cored arc welding 认领
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作者 Mohammad Khosravi Mohammad Mansouri +1 位作者 Ali Gholami Yadollah Yaghoubinezhad 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2020年第4期505-514,共10页
The effect of graphene oxide(GO)and reduced graphene oxide(RGO)nanosheets on the microstructure and mechanical properties of welded joints of mild steel was evaluated by flux-cored arc welding.GO was synthesized by th... The effect of graphene oxide(GO)and reduced graphene oxide(RGO)nanosheets on the microstructure and mechanical properties of welded joints of mild steel was evaluated by flux-cored arc welding.GO was synthesized by the Hummer’s method and was reduced under hydrothermal conditions at a pressure of 1.1 MPa at 180°C for 12 h.1,3,and 10 mg/mL paste fillers were used in GO and RGO,and applied to the weld notch.The results clearly showed that by increasing the concentration of RGO up to 10 mg/mL,the tensile strength and hardness of the weld metal were improved by approximately 20.5%and 38.4%,respectively,because the coarse grains were changed into fine domains.The domain of the nanosheets cluster was 19.85×10^?9 m.Specifically,the RGO nanosheets contributed to modifying the mechanical properties of the welded steel,likely due to dislocation pinning. 展开更多
关键词 GRAPHENE OXIDE reduced GRAPHENE OXIDE FLUX-CORED arc welding steel mechanical properties
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海藻酸钠-乳清蛋白复合益生菌微胶囊的构建及性能评价 认领
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作者 周莉 王晓瑞 +2 位作者 谭静 平洋 徐钟 《中国食品添加剂》 CAS 2020年第4期108-113,共6页
将两歧双歧杆菌包埋在海藻酸钠和乳清蛋白中制成微胶囊,探索影响制备益生菌微胶囊的因素,通过正交实验确定最佳的工艺参数及条件,并对益生菌微胶囊的耐酸、肠溶性等特性展开研究。制备微胶囊的最佳工艺参数:海藻酸钠浓度为3%,乳清蛋白... 将两歧双歧杆菌包埋在海藻酸钠和乳清蛋白中制成微胶囊,探索影响制备益生菌微胶囊的因素,通过正交实验确定最佳的工艺参数及条件,并对益生菌微胶囊的耐酸、肠溶性等特性展开研究。制备微胶囊的最佳工艺参数:海藻酸钠浓度为3%,乳清蛋白浓度为10%,氯化钙浓度为2%,搅拌速度800r/min。此条件下包埋率达到(78.0±2.0)%。经人工胃液处理后菌体存活率≥70%,在模拟肠液中60min后能够完全释放出来,可显著提高两歧双歧杆菌在模拟消化液处理后或在4℃储藏期内的存活率。本研究为益生菌微胶囊的进一步开发利用奠定基础。 展开更多
关键词 益生菌 微胶囊 性能
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聚4-甲基-1-戊烯的结构与性能 认领
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作者 赵彤 于泓锦 +2 位作者 薛增增 李丹婷 杨明山 《现代塑料加工应用》 CAS 北大核心 2020年第2期5-8,共4页
通过红外光谱、差示扫描量热、力学性能与耐热性能、透光率和动态力学性能测试等测试分析考察了聚4-甲基-1-戊烯(PMP)的结构与性能,并与几种传统工程材料进行对比分析。结果表明:PMP是一种具有优异的透光性和耐热性,且在力学性能、电性... 通过红外光谱、差示扫描量热、力学性能与耐热性能、透光率和动态力学性能测试等测试分析考察了聚4-甲基-1-戊烯(PMP)的结构与性能,并与几种传统工程材料进行对比分析。结果表明:PMP是一种具有优异的透光性和耐热性,且在力学性能、电性能和加工性能方面表现优良的新型聚烯烃树脂。 展开更多
关键词 聚4-甲基-1-戊烯 结构 性能
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Basic Physical Properties and Degradability of Tungsten Wire Fibers 认领
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作者 朱烨佳 马颜雪 +2 位作者 关国平 孟粉叶 李毓陵 《东华大学学报:英文版》 EI CAS 2020年第1期50-54,共5页
In order to explore the feasibility of tungsten filament as biomedical metal material,this article conducted a series of performance tests on two different thicknesses of black tungsten filament and two different thic... In order to explore the feasibility of tungsten filament as biomedical metal material,this article conducted a series of performance tests on two different thicknesses of black tungsten filament and two different thicknesses of white tungsten filament.It mainly tested the basic physical properties of the tungsten filament including the longitudinal cross-section of the fiber,the fiber diameter,the mechanical properties of the fiber and the biodegradability,and analyzed the results.The results showed that the breaking force of tungsten filament was about 3000MPa.And whether it was black tungsten filament or white tungsten filament,the larger the diameter,the greater the breaking force,and the breaking strength of the tungsten filament was much larger than the breaking strength of the steel wire.The larger the diameter of the tungsten filament,the slower the degradation rate.During the two months,the mass loss rate of the thick black tungsten filament was 59.40%,thin black tungsten filament was 83.88%,thick white tungsten filament was 47.39%,thin white tungsten filament was 72.29%,the degradation rate of thick tungsten wire was nearly half of the thin,and degradation mainly occured in the first months. 展开更多
关键词 TUNGSTEN FILAMENT DEGRADATION performance MECHANICAL properties DIAMETER
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Underwater pulsed spark discharge influenced by the relative position between the top of a pin electrode and an insulating tube 认领
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作者 高旭东 王继选 +4 位作者 高艳丰 闫红艳 薛凯强 邓星男 杨新 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2020年第5期35-43,共9页
Needle-to-plane geometry has been widely investigated and used in underwater pulsed discharges.The position relationship between the needle tip and insulation layer significantly affects the discharge patterns.We carr... Needle-to-plane geometry has been widely investigated and used in underwater pulsed discharges.The position relationship between the needle tip and insulation layer significantly affects the discharge patterns.We carried out experiments on underwater pulsed discharge with the needle tip protruding from,recessing into,and flushing with the insulating tube.The results are as follows.First,underwater pulsed discharge has a strong randomness under the experimental conditions.Different discharge patterns appeared under the same experimental environment.Second,recession into the insulator surface led to a higher probability of occurrence but a lower strength of spark discharge than protrusion.Third,between the needle tip protruding from and recessing into the insulation material,the average speed of propagation of underwater pulsed spark discharge decreased by an order of magnitude.The study shows that the optimum length of needle tip protruding from the insulation layer is 1 mm to obtain a strong underwater pulsed spark discharge. 展开更多
关键词 discharge strength development speed of discharge channel plasma properties randomicity of spark discharge underwater pulsed spark discharge
Mechanical and corrosion fatigue behaviors of gradient structured 7B50-T7751 aluminum alloy processed via ultrasonic surface rolling 认领
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作者 Xingchen Xu Daoxin Liu +2 位作者 Xiaohua Zhang Chengsong Liu Dan Liu 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第5期88-98,共11页
In this work,ultrasonic surface rolling process(USRP)was utilized to produce a gradient structured layer on 7 B50-T7751 aluminum alloy,and the mechanical properties and corrosion fatigue behavior of treated samples we... In this work,ultrasonic surface rolling process(USRP)was utilized to produce a gradient structured layer on 7 B50-T7751 aluminum alloy,and the mechanical properties and corrosion fatigue behavior of treated samples were studied.These results reveal that underwent USRP,a 425~m thick gradient structure and a 700~m deep compressive residual stress field are created,aluminum grain size become fine(~67 nm),and the corrosion rate of treated surface reduces by 60.08%owing to the combined effect of compressive residual stress and surface nanocrystallization.The corrosion fatigue strength is enhanced to 117%of that of 7 B50 Al alloys by means of USRP due to the introduced compressive residual stress,which is considered as the major favorable factor in suppressing the initiation and early propagation of corrosion fatigue cracks.Besides,the gradient structure is an important factor in providing a significant synergistic contribution to the improvement of corrosion fatigue performance. 展开更多
关键词 Aluminum alloy MECHANICAL properties CORROSION fatigue behavior Gradient structure COMPRESSIVE residual stress ULTRASONIC surface ROLLING process
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