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Research on Infrared Emissivity and Laser Reflectivity of Sn_(1−x)Er_(x)O_(2)Micro/Nanofibers Based on First-Principles 被引量:1
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作者 Yuanjia Xia Fang Zhao +2 位作者 Zhizun Li Zhaogang Cheng Jianwei Hu 《Journal of Renewable Materials》 SCIE EI 2023年第2期921-936,共16页
Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target produc... Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material. 展开更多
关键词 Micro/nano fibers Er^(3+)doping SnO_(2) laser and infrared compatible stealth material
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CHARACTERIZATION OF AMPHIPHILIC AND MICROPHASE SEPARATED GRAFT COPOLYMERS Ⅱ SURFACE CHARACTERIZATION AND IN VITRO BLOOD-COMPATIBILITY ASSESSMENT OF POLYSTYRENE-GRAFT-ω-STEARYLPOLY (ETHYLENE OXIDE)
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作者 邱永兴 俞小洁 +1 位作者 封麟先 杨士林 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第2期112-125,共14页
This paper reported the research results concerning the surface characterization ofpolystyrene-graft-w-stearyl poly(ethylene oxide) (PS-g-SPEO) by means of XPS,contactangle measurement and TEM, and its in vitro blood ... This paper reported the research results concerning the surface characterization ofpolystyrene-graft-w-stearyl poly(ethylene oxide) (PS-g-SPEO) by means of XPS,contactangle measurement and TEM, and its in vitro blood compatibility assessment by measuringthe plasma recalcification time (RT) and partial thromboplastin time (PTT). The XPSresults demonstrated that the surface and bulk composition of the PS-g-SPEO graftcopolymers differ remarkably from each other,and that SPEO component was constantlyenriched at the copolymer/air interface. Contact angle studies indicated that the surfacewater wettability can be adjusted effectively by changing the composition of the copolymer.PS-g-SPEO graft copolymers can undergo microphase separation as clearly illustrated byTEM photographs. The relationship between the surface properties of PS-g-SPEO graftcopolymer and its blood compatibility was also discussed. 展开更多
关键词 Polystyrene-g-w-stearyl-poly (ethylene oxide) Surface properties Graft copolymer Blood compatible material
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Modeling of Rolling Contact Friction of Ball Bearings at Elevated Temperature
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作者 胡瑞 刘佐民 《Journal of Donghua University(English Edition)》 EI CAS 2011年第6期547-551,共5页
In order to predict the rolling friction coefficient and analyze the effects of material compatibility on the friction coefficient at elevated temperature(from room temperature to 600℃),a theoretic computation model ... In order to predict the rolling friction coefficient and analyze the effects of material compatibility on the friction coefficient at elevated temperature(from room temperature to 600℃),a theoretic computation model was developed based on bearing's elastic contact hysteresis and related material characteristic parameters.Some examples were carried out to verify the feasibility of the model.The research results show that the material compatibility has significant effects on rolling friction coefficient,especially the modulus of elasticity and the expansion coefficient of material,and results also show the rolling friction coefficient of the matched pair between GCr15 and Si3N4 is the smallest comparing with that between GCr15 and M50(or ASP-23,or GCr15) when making GCr15,M50,ASP-23,and Si3N4 materials as bearing's rolling balls and GCr15 material as bearing's inner and outer rings.Further research indicates that the working temperature also has played an important role in the rolling friction coefficient of the ball bearing,moreover,the friction coefficient of the matched pair of M50 and Si3N4 behaves most stably at elevated temperature. 展开更多
关键词 high temperature field ball bearing friction coefficient material compatibility
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Material Compatibility of Hexamethyldisiloxane as Organic Rankine Cycle Working Fluids at High Temperatures
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作者 DAI Xiaoye SHI Lin QIAN Weizhong 《Journal of Thermal Science》 SCIE EI CAS CSCD 2020年第1期25-31,共7页
The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy utilization.High temperature ORCs have attracted particular interest because of their high thermal effici... The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy utilization.High temperature ORCs have attracted particular interest because of their high thermal efficiencies and outputs.The material compatibility of working fluid is a significant limitation for the working fluid selection and system design for high temperature ORCs.This work presents a method for studying the material compatibility of ORC working fluids based on the calculated conditions of the ORCs and matching of components,temperatures,and materials.Hexamethyldisiloxane(MM)was chosen as the test fluid.The experimental results show that 304 stainless steel has better compatibility with MM than copper as the material of evaporators.Fluoric rubber is not a suitable sealing material for high temperature ORCs with MM as the working fluids because of the bad compatibility.Mineral oil has better compatibility with MM than polyol ester(POE)lubricant as the lubricant for the fluid pump. 展开更多
关键词 organic Rankine cycle(ORC) material compatibility high temperatures hexamethyldisiloxane(MM)
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