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Thermal energy dependent transient permittivity of epsilon-near-zero material

science China(Physics,Mechanics & Astronomy) 2022年第8期65卷 96-101页

作者： Heng Wang Lixun Sun Kang Du Wending Zhang SooJin Chua Guixin Li Ting Mei MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an710129China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen518055China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen518055China Department of Electrical and Computer Engineering National University of SingaporeSingapore117583Singapore LEES Program Singapore-MIT Alliance for Research&Technology(SMART)Singapore138602Singapore

Transparent conductive oxides exhibit attractive optical nonlinearity with ultrafast response and giant refractive index change near the epsilon-near-zero(ENZ) wavelength, originating from the intraband dynamics of conduction electrons. The optical nonlinearity of ENZ materials has been explained by using the overall-effective-mass and the overall-scattering-time of electrons in the extended Drude model. However, their response to optical excitation is yet the last building block to complete the theory. In this paper, the concept of thermal energy is theoretically proposed to account for the total energy of conduction electrons exceeding their thermal equilibrium value. The time-varying thermal energy is adopted to describe the transient optical response of indium-tin-oxide(ITO), a typical ENZ material. A spectrally-resolved femtosecond pump-probe experiment was conducted to verify our theory. By correlating the thermal energy with the pumping density, both the giant change and the transient response of the permittivity of ITO can be predicted. The results in this work provide a new methodology to describe the transient permittivities of ENZ materials, which will benefit the design of ENZ-based nonlinear photonic devices.

关键词： epsilon-near-zero optical nonlinearity transient response thermal energy hot electron indium tin oxide

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Effect of Heat Treatments on Microstructure and mechanical Properties of Fe-Mn-Ni-Al-Gd Shape Memory Alloy

Effect of Heat Treatments on Microstructure and Mechanical P...

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2023 Sharjah International Conference on Physics of Advanced materials, SICPAM 2023

作者： Mustafa, Faisal Egilmez, Mehmet Abuzaid, Wael El-Khatib, Sami Department of Physics American University of Sharjah Sharjah26666 United Arab Emirates Materials Science and Engineering Program American University of Sharjah Sharjah26666 United Arab Emirates Department of Mechanical Engineering American University of Sharjah Sharjah26666 United Arab Emirates

There are significant scientific and industrial efforts to develop and optimize Iron-based shape memory alloys (SMA) such as FeMnNiAl for cost-sensitive applications. This alloy system shows shape memory and superelastic properties across a large temperature range. However, many studies have pointed out the need for rather complex thermo-mechanical treatments for the optimization of the SMA properties. In addition, works considering the effects of alloying on the development of microstructures that are more conducive to pseudo-elasticity in this system remain limited. Hence, systematic studies aiming at the investigation of the microstructural evolution of the FeMnNiAl(Gd) system are of great interest. In this study, solution heat treatment is done to tune the microstructure for optimum mechanical properties. The effect of phase distribution on mechanical properties is investigated at different heat treatments. Whereas cyclic heat treatment induced abnormal grain growth (AGG) in all samples, so large grains were obtained. The phase variation and elemental composition are analyzed by X-ray diffraction and Energy Dispersive Spectroscopy, respectively. The microstructure and phase distribution are observed using Scanning Electron Microscope and then related to the microhardness results. The microstructure has a good correlation with mechanical properties where the fine distribution of phases results in a higher hardness number. © Published under licence by IOP Publishing Ltd.

关键词： Microstructure

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Optothermal Manipulation at Fluid Interfaces

Optothermal Manipulation at Fluid Interfaces

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Kim, Youngsun Ponce, Carolina Chen, Zhihan Zheng, Yuebing Materials Science & Engineering Program Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States

Optothermal manipulation of particles at fluid interfaces was studied with a film of gold nanoparticles assembled at aqueous/oil interfaces. The unique optothermal behaviors of particles and fluid interfaces under opt... 详细信息

ISBN: (纸本)9781957171258

关键词： Gold nanoparticles

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Computational Modeling of Radiation Effects in Carbon Fiber-Reinforced Polyethylene Composites 38

Computational Modeling of Radiation Effects in Carbon Fiber-...

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38th Technical Conference of the American Society for Composites, ASC 2023

作者： Li, Fuyue Woodrough, Mary Deo, Chaitanya School of Materials Science and Engineering Georgia Institute of Technology North Avenue AtlantaGA30332 United States Nuclear and Radiological Engineering Program GWW School of Mechanical Engineering Georgia Institute of Technology North Avenue AtlantaGA30332 United States

ISBN: (纸本)9781605956916

Radiation effect in carbon fiber-filled polyethylene composites are of importance in space and aircraft applications. A two-fold approach is employed to study radiation effects in carbon nanotube polyethylene as the exemplar. First, a radiation transport model is created with a single-wall carbon nanotube (SWCNT) as thin carbon slab superimposed on a slab of medium-density polyethylene matrix. Different weight fractions of SWCNT are examined and compared with an integrated model for the shielding abilities of galactic cosmic radiation. Second, molecular dynamics simulation with bond-order force field are conducted for 350 eV carbon recoil cascade simulation. Preliminary results discuss the effect of SWCNT on the radiation damage of crystalline polyethylene. Transport simulation demonstrate the efficacy of the slab model in predicting the shielding abilities and concluded that the dose increases with increasing SWCNT filler. Molecular dynamics simulations demonstrate that adding SWCNT enhances the radiation resistance with fewer free molecules produced. © 2023 by DEStech Publications, Inc. and American Society for Composites. All rights reserved.

关键词： Single-walled carbon nanotubes (SWCN)

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Self-Attenuating Graphene-Based Antennas Utilizing Polyvinylidene Fluoride (PVDF) Substrates

Self-Attenuating Graphene-Based Antennas Utilizing Polyvinyl...

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Microwave and Antenna Symposium (IMAS), International

作者： Josef Frankhouse Evans Addo-Mensah Uche Wejinya Department of Mechanical Engineering University of Arkansas - Fayetteville Materials Science and Engineering Graduate Program University of Arkansas - Fayetteville

ISBN: (数字)9798350356359

ISBN: (纸本)9798350356366

In this study, a Terahertz (THz) band antenna which can regulate its own resonant frequency without the requirement of manual adjustment is simulated. A polyvinylidene fluoride (PVDF) substrate is applied onto a rectangular graphene patch antenna. With a voltage potential applied onto the PVDF, the patch antenna can attenuate its frequency by physically changing the shape of the antenna, and in turn its resonant frequency. These antennas are within a 0.1 THz band between 1.32 THz to 1.22 THz measured from a radial bend of a flat surface to r = 75 μm, fitting into a return loss (S11) above -30 dB. Although the return loss did not show consistency, the resonating frequency shifted at a linear rate relative to the cylindrical bending.

关键词： Microwave antennas Patch antennas Graphene Resonant frequency Prototypes Bandwidth Bending Loss measurement Substrates Terahertz communications

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Manufacturable Novel Nanogrease with Superb Physical Properties

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Nanomanufacturing and Metrology 2021年第4期4卷 289-297页

作者： Hammad Younes Ding Lou Haiping Hong Huahui Chen Hongtao Liu Yinhuai Qiang Department of Electrical Engineering South Dakota School of Mines and TechnologyRapid CitySD 57701USA Department of Material Science and Engineering School of Mechanical and Electrical EngineeringChina University of Mining and TechnologyBeijing 100083China School of Material Science and Engineering China University of Mining and TechnologyXuzhou 221166China

High-performance nanogrease manufactured from carbon nanomaterials is observed to be stable and homogeneous and have superb physical properties,such as thermal and electrical conductivities,compared with current commercial greases made of lithium,calcium,and *** the first time,carbon nanomaterials have been observed to disperse well as the sole thickeners in oil systems,e.g.,polyalphaolefin and polyester(ROYCO),without the aid of any chemical ***-dimensional percolation network structures that exist among carbon nanomaterials are easily scalable,which can be attributed to the intermolecular van der Waals ***,the introduction of hydrogen bonding in any form to grease significantly increases its thermal and electrical conductivities and substantially reduces the weight percentage of carbon nanomaterials needed to fabricate stable *** example,loading of only 1.4 wt%hydroxyl-functionalized multiwalled carbon nanotube(MWNT-OH)with Krytox XHT750 oil leads to a 37.8%increase in thermal ***,75%glycerol,25% water,and 4.5 wt% MWNT-OH yielded the lowest electrical resistivity of 10.0 Ω *** finding can be extended to hydrogen bonding materials with functional groups,such as OH,COOH,F,and *** nanogrease reported in this study has been manufactured using the three-roll mill method,which is an easy and cost-effective method,as the loading weight percentage of carbon nanomaterials to fabricate stable grease decreases from 12 wt% to 3-4 wt%.Furthermore,the process is easily scalable,reproduced,and *** novel high-performance nanogrease has a high commercial value and numerous applications and could replace current commercial greases.

关键词： Nanogrease Three-dimensional network percolation structure Carbon nanomaterial Van der Waals forces Hydrogen bonding Thermal conductivity Electrical conductivity

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CALPHAD coupled phase-field simulation of microstructural evolution during active metal brazing with Ag-Cu-Sn-Ti alloy 28

CALPHAD coupled phase-field simulation of microstructural ev...

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28th Congress of the International Federation for Heat Treatment and Surface engineering, IFHTSE 2023

作者： Morino, Takumi Hirosawa, Shoichi Ode, Machiko Abe, Taichi Mori, Yoichiro Suenaga, Seiichi Department of Mechanical Engineering and Materials Science Yokohama National University 79-5 Tokiwadai Hodogaya-ku Kanagawa Yokohama240-8501 Japan Computational Material Science Center National Institute of Material Science Ibaraki Tsukuba305-0047 Japan Toshiba Materials Corporation Kanagawa Yokohama235-8522 Japan

ISBN: (纸本)9781713889533

In this study, a new CALPHAD database of Ag-Cu-Sn-Ti system has been proposed, followed by a phase-field simulation to predict the solidification microstructure of the quaternary alloy during active metal brazing that joins copper circuits and Si3N4 substrates. From the CALPHAD coupled phase-field simulation, it was revealed that melting of copper circuit and a reaction of Ti with Si3N4 substrate decreases the amount of primary Sn3Ti5, resulting in an increased Sn concentration within Ag-Cu-Sn-Ti liquid and thus a lowering of the temperature at which solidification of the brazing metal is completed. Therefore, the developed phase-field program of our own coding can successfully clarify the effect of copper circuit melting and Ti depletion during active metal brazing, which cannot be experimentally monitored. © 2023 28th IFHTSE 2023 Congress. All rights reserved.

关键词： Tin alloys

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Moderate-Refractive-Index Mie Resonators for Versatile Modulation of Two-Dimensional Excitons

Moderate-Refractive-Index Mie Resonators for Versatile Modul...

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Fang, Jie Zheng, Yuebing Materials Science & Engineering Program Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States

ISBN: (纸本)9781957171258

By coupling well-designed moderate-refractive-index Mie resonators to monolayer semiconductors, we have demonstrated efficient modulation of two-dimensional excitons in multiple dimensions: far-field excitonic radiation patterns, intrinsic excitonic quantum dynamics, and bosonic exciton-polariton emission lines. © 2023 The Author(s)

关键词： Resonators

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Solar evaporator coupled with strong/weak convection and its cascade utilization

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science Bulletin 2025年第8期70卷 1264-1274页

作者： Zhengtong Li Jia-Han Zhang Jing Zhang Peng Yan Tao Yang Chao Yang Peng Lin Taotao Meng Meng An Yingtang Zhou Xingtao Xu The National Key Laboratory of Water Disaster Prevention Yangtze Institute for Conservation and DevelopmentState Key Laboratory of Hydrology-Water Resources and Hydraulic EngineeringHohai UniversityNanjing 210098China Electronic-Photonic Smart Sensing Device R&D Team Inner Mongolia Key Laboratory of Intelligent Communication and Sensing and Signal ProcessingSchool of Electronic Information EngineeringInner Mongolia UniversityHohhot 010021China Ningbo Key Laboratory of Green Petrochemical Carbon Emission Reduction Technology and Equipment Zhejiang Institute of Tianjin UniversityNingbo 315201China Department of Mechanical Engineering The University of TokyoTokyo113-8656Japan Marine Science and Technology College Zhejiang Ocean UniversityZhoushan 316022China College of Material Science and Engineering Nanjing Forestry UniversityNanjing 210037China

Modulating the macro/nanoarchitecture of evaporators to effectively harness diverse renewable energy sources is of paramount importance for optimizing the performance of solar-driven interfacial *** by the geometric structure of a windmill,we designed an innovative solar evaporator that expertly harnesses both strong and weak *** the purification of heavy metal wastewater,the maximum evaporation rate can reach 4.95 kg m^(−2)h^(−1)under one sun irradiation by introducing an ultralow wind flow(0.1 m s^(−1)),yielding an evaporation rate that is twice that of traditional ***,the gradual deposition of inorganic salt sediments on the evaporator surface is clearly *** address this issue,we present several innovative proof-of-concept cascade treatments that significantly extend the evaporator’s operational *** innovative design and exceptional performance of this solar evaporator open avenues for advancements in sustainable water treatment,energy generation,and environmental remediation.

关键词： Interfacial evaporation Petiole-based solar evaporators Secondary flow Cascade utilization Wastewater treatment

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Efficacy of Fleurya aestuans on Mild Steel Protection in Acidic Systems: Combined Gravimetry, Gasometry, and Electrochemical Evaluations

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Journal of Bio- and Tribo-Corrosion 2024年第2期10卷 1-15页

作者： Obike, Anthony I. Udorji, Franklin I. Ekerenam, Okpo O. Emori, Wilfred Onyeije, Ugomma C. Onyedinma, Ukaogo P. Okonkwo, Paul C. Ikeuba, Alexander I. Department of Pure and Industrial Chemistry Abia State University Uturu Nigeria Department of Biochemistry School of Pure & ampApplied Sciences Federal University of Technology Ikot Abasi Nigeria School of Materials Science and Engineering Sichuan University of Science and Engineering Sichuan Zigong643000 China Key Laboratory of Material Corrosion and Protection of Sichuan Province Sichuan Zigong643000 China Department of Pure and Industrial Chemistry Nnamdi Azikiwe University Awka Nigeria Mechanical and Mechatronics Engineering Dhofar University Salalah Oman Materials Chemistry Research Group Department of Pure and Applied Chemistry University of Calabar Calabar Nigeria

The anticorrosion studies of Fleurya aestuans extract on mild steel in acidic media was carried out in 2 M HCl and 1 M H2SO4 using gasometric, gravimetric, and electrochemical techniques at room temperature and at elevated temperatures (303 and 323 K). In all test settings, the inhibitory effectiveness changed in direct proportion to the extract concentration and in inverse proportion to the exposure duration and temperature. The anticorrosion potential of the extract is attributed to the adsorption of its phytoconstituents on the metal surface, blocking the active corrosion sites on mild steel. The adsorption mechanism conformed to the Langmuir, Freundlich, and Temkin adsorption isotherm models with the best fits recorded for the Langmuir model (R2 of 0.9777 and 0.9850 in HCl and H2SO4, respectively). The calculated thermodynamic parameters, namely Gibbs free energy (∆Goads), activation energy (Ea), and heat of adsorption (Qads) all favored a spontaneous and exothermic physical adsorption reaction mechanism of the extract. Potentiodynamic polarization experiments revealed that the extract displayed mixed-type corrosion suppression ability and electrochemical impedance spectroscopy (EIS) evaluations showed increasing charge transfer resistance with increasing extract concentration. Moreover, scanning electron microscopy examinations disclosed the presence of a protective covering on the surface of mild steel coupons in the acid solutions containing F. aestuans extract. The outcomes of the several tests show strong correlations with one another. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

关键词： Adsorption

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