This document summarizes a research seminar given by Dr. Liping Wang at National Chiao Tung University in Taiwan on October 29, 2019. The seminar covered Dr. Wang's research group's work on near-field thermal radiation and its applications. Key areas discussed included measurements of super-Planckian near-field thermal radiation using aluminum thin films and doped silicon, and theoretical predictions of gate-tunable near-field radiative heat flux using graphene that could allow thermal modulation and switching.
20191027 Wang Seminar at NTHU (Radiative Thermal Control).pdflwang78
The document summarizes a research seminar given by Dr. Liping Wang on using nanostructured materials and metamaterials to control thermal radiation for passive radiative cooling and active heat control, including work on silicon carbide metasurfaces, lithium fluoride emitters, and vanadium dioxide metamaterials and metafilms that enable tunable thermal emission.
20191101 Wang Invited Talk at APTSE (Thermal Energy Harvesting and Conversion)lwang78
This document summarizes research on using nano-engineered materials for high-efficiency solar thermal energy harvesting and conversion. It discusses using metamaterials and metafilms as selective absorbers and emitters to control the spectral properties of materials. Experimental results show the metafilm absorbers maintain high solar absorptance while significantly reducing infrared emittance, even after high-temperature testing. Theoretical analyses predict the metafilm designs can improve the efficiency of solar thermophotovoltaic energy conversion systems from around 10% to over 17% at 50 suns concentration by optimizing the material structures and incorporating a cavity reflector. Current work involves fabricating and testing a solar thermophotovoltaic experimental setup using the metafilm
2023Dec ASU Wang NETR Group Research Focus and Facility Overview.pptxlwang78
The document summarizes the research of Dr. Liping Wang's Nano-Engineered Thermal Radiation Group at Arizona State University. The group focuses on efficient energy harvesting, power conversion, and radiative thermal control using thermophotonic absorption and emission. Key areas of research include selective thermal emission and absorption for solar energy applications, near-field thermal radiation, and tunable thermal emission for applications like radiative cooling. The group has state-of-the-art facilities for optical characterization, thermophotonic energy conversion testing, and measuring near-field radiation.
Arquivo do seminário apresentado pelo professor Fernando Alvarez, pesquisador da seção Unicamp do Instituto Nacional de Engenharia de Superfícies, no dia 20 de agosto de 2013, na seção UCS do Instituto, para um público de 30 estudantes e professores de cursos de graduação e pós-graduação.
This document describes a technique for measuring interdiffusion in metallic multilayers during rapid heating using in situ X-ray reflectivity measurements. Key points:
- X-ray reflectivity is a sensitive probe for measuring interdiffusion as it is affected by changes in the composition modulation of the multilayer over time.
- A curved sample approach is used to collect a full reflectivity pattern simultaneously over a range of angles using a position-sensitive detector, allowing for in situ measurements during heating.
- Initial interdiffusion rates are determined from the decay of reflectivity peak intensities with increasing temperature. The activation energy for interdiffusion is found to be consistent with a grain boundary diffusion mechanism.
- At
The presentation file on workshop on Neutron and X-ray Characterisation on Caloric Materials, introduction to neutron scattering experiment with triple axis spectrometer for material scientist
DESIGN, OPTIMIZATION AND DEVELOPMENT OF SOLAR THERMAL HEAT RECEIVER SYSTEM WI...Journal For Research
Against a backdrop of our world’s changing climate solar thermal power generation shows great potential to move global energy production away from fossil fuels to non-polluting sources. A parameter study was conducted based on the previous analysis to improve specific aspects of the initial design using a value of benefit analysis to evaluate the different design. This project focused on the design, analysis and verification of a high temperature solar receiver. Computational Fluid Dynamic (CFD) analysis of Radiation model is carried out with new geometry design of receiver. Discrete Transfer Radiation Model (DTRM) model is used for numerical simulation.
This document discusses the design, optimization, and development of a solar thermal heat receiver system with a parabolic concentric collector. A computational fluid dynamics (CFD) analysis was conducted using a discrete transfer radiation model (DTRM) to simulate heat transfer and optimize the receiver design. The CFD analysis found that the receiver design achieved an average temperature of 453K on the receiver wall and outlet temperature of air at 392K with an air mass flow rate of 0.08kg/s. Higher temperatures can be achieved by using materials with higher reflectivity for the reflector and selecting optimal working fluids.
20191027 Wang Seminar at NTHU (Radiative Thermal Control).pdflwang78
The document summarizes a research seminar given by Dr. Liping Wang on using nanostructured materials and metamaterials to control thermal radiation for passive radiative cooling and active heat control, including work on silicon carbide metasurfaces, lithium fluoride emitters, and vanadium dioxide metamaterials and metafilms that enable tunable thermal emission.
20191101 Wang Invited Talk at APTSE (Thermal Energy Harvesting and Conversion)lwang78
This document summarizes research on using nano-engineered materials for high-efficiency solar thermal energy harvesting and conversion. It discusses using metamaterials and metafilms as selective absorbers and emitters to control the spectral properties of materials. Experimental results show the metafilm absorbers maintain high solar absorptance while significantly reducing infrared emittance, even after high-temperature testing. Theoretical analyses predict the metafilm designs can improve the efficiency of solar thermophotovoltaic energy conversion systems from around 10% to over 17% at 50 suns concentration by optimizing the material structures and incorporating a cavity reflector. Current work involves fabricating and testing a solar thermophotovoltaic experimental setup using the metafilm
2023Dec ASU Wang NETR Group Research Focus and Facility Overview.pptxlwang78
The document summarizes the research of Dr. Liping Wang's Nano-Engineered Thermal Radiation Group at Arizona State University. The group focuses on efficient energy harvesting, power conversion, and radiative thermal control using thermophotonic absorption and emission. Key areas of research include selective thermal emission and absorption for solar energy applications, near-field thermal radiation, and tunable thermal emission for applications like radiative cooling. The group has state-of-the-art facilities for optical characterization, thermophotonic energy conversion testing, and measuring near-field radiation.
Arquivo do seminário apresentado pelo professor Fernando Alvarez, pesquisador da seção Unicamp do Instituto Nacional de Engenharia de Superfícies, no dia 20 de agosto de 2013, na seção UCS do Instituto, para um público de 30 estudantes e professores de cursos de graduação e pós-graduação.
This document describes a technique for measuring interdiffusion in metallic multilayers during rapid heating using in situ X-ray reflectivity measurements. Key points:
- X-ray reflectivity is a sensitive probe for measuring interdiffusion as it is affected by changes in the composition modulation of the multilayer over time.
- A curved sample approach is used to collect a full reflectivity pattern simultaneously over a range of angles using a position-sensitive detector, allowing for in situ measurements during heating.
- Initial interdiffusion rates are determined from the decay of reflectivity peak intensities with increasing temperature. The activation energy for interdiffusion is found to be consistent with a grain boundary diffusion mechanism.
- At
The presentation file on workshop on Neutron and X-ray Characterisation on Caloric Materials, introduction to neutron scattering experiment with triple axis spectrometer for material scientist
DESIGN, OPTIMIZATION AND DEVELOPMENT OF SOLAR THERMAL HEAT RECEIVER SYSTEM WI...Journal For Research
Against a backdrop of our world’s changing climate solar thermal power generation shows great potential to move global energy production away from fossil fuels to non-polluting sources. A parameter study was conducted based on the previous analysis to improve specific aspects of the initial design using a value of benefit analysis to evaluate the different design. This project focused on the design, analysis and verification of a high temperature solar receiver. Computational Fluid Dynamic (CFD) analysis of Radiation model is carried out with new geometry design of receiver. Discrete Transfer Radiation Model (DTRM) model is used for numerical simulation.
This document discusses the design, optimization, and development of a solar thermal heat receiver system with a parabolic concentric collector. A computational fluid dynamics (CFD) analysis was conducted using a discrete transfer radiation model (DTRM) to simulate heat transfer and optimize the receiver design. The CFD analysis found that the receiver design achieved an average temperature of 453K on the receiver wall and outlet temperature of air at 392K with an air mass flow rate of 0.08kg/s. Higher temperatures can be achieved by using materials with higher reflectivity for the reflector and selecting optimal working fluids.
This document provides an overview of the Institute of Nanoscience and its research activities related to semiconductor nanostructures and their applications. The institute has over 250 researchers studying the fundamental properties and manipulation of nanoscale systems through synthesis, fabrication, experimental and theoretical studies of nanostructures and devices. Key areas of research include semiconductor nanowires for applications in electronics, optoelectronics and spintronics. Heterostructured nanowires of InAs, InSb and InP are investigated for high mobility transistors and terahertz detectors. Strain-driven self-assembly is used to create 3D nanostructures for applications in sensing, energy harvesting and photonics.
This document summarizes research on topological transport in antimony (Sb) quantum wells. Key points include:
1) Sb is predicted to be a topological semimetal or insulator depending on film thickness. Thin Sb films were grown by MBE to suppress bulk conduction and study topological surface states.
2) Magneto-transport measurements on Hall bar devices show weak antilocalization, consistent with topological surface states. Parameters like the phase breaking length are independent of film thickness.
3) A simple two-channel model of surface and bulk conduction quantitatively fits the high field magnetoresistance evolution with decreasing thickness.
Overall the results provide evidence for topological surface states in thin Sb
The document discusses nantennas, which are nanoscopic antennas that can convert solar radiation into electricity. Nantennas address many limitations of traditional photovoltaic cells. They work by absorbing electromagnetic waves from solar radiation and thermal earth radiation. This induces an alternating current in the nantenna, which is then rectified into direct current using a diode. Nantennas show promise for applications like self-charging batteries and could be mass produced inexpensively using roll-to-roll manufacturing. Future research aims to improve rectifier efficiency and upscale the technology for widespread use.
Ph d defense_rajmohan_muthaiah_University_of_oklahoma_07_28_2021Rajmohan Muthaiah
This slide describes the thermal transport in polymers, polymer nanocomposites and semiconductors using molecular dynamics simulations and first principles calculations
MRS Spring 2009 Poster Rare Earth Diffused GaNmoluen
The document discusses research on rare earth (RE)-doped gallium nitride (GaN) films grown via diffusion doping with neodymium (Nd) and erbium (Er). Key findings include:
1) Nd-doped and Er-doped GaN samples exhibited room temperature ferromagnetism and near-infrared luminescence. Emission wavelengths matched telecommunications applications.
2) Increasing silicon doping decreased the ferromagnetic properties, as silicon competes with rare earths for gallium sites. Luminescence intensity was less affected by silicon doping.
3) Annealing time affected luminescence intensity, which increased then decreased with longer annealing, suggesting
Laser trapped mirrors could enable the construction of large, lightweight optical systems in space. A laser traps microscopic particles at the interference fringes created by its reflection between two deflectors, arranging the particles into a reflective mirror surface. Key challenges include maintaining the trap against particle evaporation from infrared background photons and understanding optical binding forces between particles. Further experiments and simulations are needed to evaluate particle design, collective behavior, trap loading and damping mechanisms to develop this technology.
This Presentation is based on our Research work carried out in GNDU Amritsar and DAVIET, Jallandhar. We fabricated Ion track filters; nanowires and some Exotic Patterns for the first time in India using simple Techniques.
Room-temperature emission at telecom wavelengths from silicon photonic crysta...Roberto Lo Savio
Light emission in crystalline silicon is the fundamental goal for the development of an all-silicon device showing efficient infrared emission at room temperature. The exploitation of optically active structural defects that generates sub-bandgap luminescence is the strategy explored here to make silicon an efficient infrared emitter around 1.5 μm.
Radiation and magneticfield effects on unsteady naturalAlexander Decker
This document discusses research on the effects of thermal radiation and magnetic fields on unsteady natural convective flow of nanofluids past an infinite vertical plate with a heat source. The following key points are discussed:
- Governing equations for the unsteady, two-dimensional flow are derived taking into account radiation, magnetic fields, and thermophysical properties of nanofluids.
- The equations are solved numerically using Laplace transform techniques. Parameters like radiation, magnetic field, heat source, and nanoparticle volume fraction are examined.
- It is found that increasing the magnetic field decreases fluid velocity, while radiation, heat source, and nanoparticle volume fraction more strongly influence velocity and temperature profiles. Nanoparticle shape
Radiation and magneticfield effects on unsteady naturalAlexander Decker
This document discusses research on the effects of thermal radiation and magnetic fields on unsteady natural convective flow of nanofluids past an infinite vertical plate with a heat source. The following key points are discussed:
- Governing equations for the unsteady, two-dimensional flow are derived taking into account radiation, magnetic fields, and thermophysical properties of nanofluids.
- The equations are solved numerically using Laplace transform techniques. Parameters like radiation, magnetic field, heat source, and nanoparticle volume fraction are examined.
- It is found that increasing the magnetic field decreases fluid velocity, while radiation, heat source, and nanoparticle volume fraction have a greater influence on fluid velocity and temperature profiles. Nan
This document summarizes Andrew Oles' PhD dissertation on modeling of solar particle receivers for hydrogen production and thermochemical energy storage. It describes particle receivers as a potential next-generation concentrating solar power technology with solid particles as the heat transfer medium. The document outlines the modeling of inert and reactive particle receivers, including simulations of prototype and commercial-scale receivers to analyze performance tradeoffs. Selective absorption in particles is investigated, showing higher efficiencies are possible by tuning infrared emissivity.
Dr. Harold Weinstock presents an overview of his program, Quantum Electronic Solids, at the AFOSR 2013 Spring Review. At this review, Program Officers from AFOSR Technical Divisions will present briefings that highlight basic research programs beneficial to the Air Force.
Greg Smestad, Leonardo Micheli, Thomas Germer, and Eduardo Fernández presented research on characterizing the optical effects of soiling on PV glass and modules. They measured the transmission of glass coupons exposed outdoors at multiple locations over 8 weeks and found soiling reduced transmission more at shorter wavelengths. Particle area coverage on the coupons correlated linearly with reduced hemispherical transmittance. Angular measurements showed soiling impacts transmission more for direct light than hemispherical. The research aims to better understand how soiling impacts PV performance globally.
Optical Characterization of PV Glass Coupons and PV Modules Related to Soilin...Greg Smestad
Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses,
Greg P. Smestad, Ph.D., Sol Ideas Technology Development
December 6th, 2017, 11:35 AM - 12:00 PM
Session 5: Characterization (Chair: Xiaohong Gu, NIST)
Atlas/NIST Workshop on PV Materials Durability
December 5-6, 2017, Gaithersburg, Maryland
National Institute of Standards and Technology, Gaithersburg, Maryland
https://www.nist.gov/el/mssd/agenda
Different types of Nanolithography technique.
Types: Electron beam lithography, Photolithography, electron-beam writing, ion- lithography, X-ray lithography, and related images, concepts and graphical views.
I hope this presentation helpful for you.
https://www.linkedin.com/in/preeti-choudhary-266414182/
https://www.instagram.com/chaudharypreeti1997/
https://www.facebook.com/profile.php?id=100013419194533
https://twitter.com/preetic27018281
Please like, share, comment and follow.
stay connected
If any query then contact:
chaudharypreeti1997@gmail.com
Thanking-You
Preeti Choudhary
Tobias junginger low energy muon spin rotation and point contact tunneling ...thinfilmsworkshop
Muon spin rotation (muSR) and point contact tunneling (PCT) are used since several years for bulk niobium studies. Here we present studies on niobium thin film samples of different deposition techniques (diode, magnetron and HIPIMS) and compare the results with RF measurements and bulk niobium results. It is consistently found from muSR and RF measurements that HIPIMS can be used to produce thin films of high RRR. Hints for magnetic impurities are found on HIPIMS and dcms samples. The Meissner effect is linear on all tested samples.
Sputtering yield and nanopattern formation study of BNSiO2 (Borosil) at eleva...Dr. Basanta Kumar Parida
Lower sputtering yield of the discharge wall material is a crucial parameter for the performance of Hall Effect Thruster (HET) [1, 2]. In this article, we report the sputtering yield of HET wall
material BNSiO2 (borosil) at elevated temperature ~600 °C using quartz crystal microbalance (QCM). We observe a linear increase in the sputtering yield with temperature and it remains stable during long duration experiments using Xe ions. Two different crystallographic orientations of borosil give a
slight variation in the yield. The higher yields for higher operating temperatures is proposed to be due to the thermal spike nature. Microscopic surface morphology shows only different grains of BNSiO2, however high resolution nanoscopic view reveals the formation of nanoripple like structures over different grains [3]. The periodicity of such features increases with ion dose (sputtering time) and temperature in the range of 70-190 nm. Local curvature dependent erosion plays crucial role in such pattern formation [4].
Reference:
1. D.M. Goebel, I. Katz, Fundamentals of Electric Propulsion, Ion and Hall Thrusters, 2008.
2. M. Ranjan, A. Sharma, A. Vaid, T. Bhatt, V. Nandalan, M.G. James, H. Revathi, S. Mukherjee, AIP
Adv. 6 (2016) 95224
3. R. M. Bradley, J.M.E. Harper, J. Vac. Sci. Technol. A 6 (1988) 2390
4. B. K. Parida, Sooraj K P, S. Hans, V. Pachchigar, S. Augustine, Remyamol T, M. R. Ajith, M. Ranjan;
Nucl. Inst and Methods B, 514 (2022) 1-7
Study of size dependence of Raman scattering in Carbon nanotubes.
To Study Temperature dependence of Raman spectra
To Study spatial distribution of temperature during laser processing
To Study Temperature rise in CNTs as a function of laser power
Theoretically calculated Vs Experimental Raman temperature
Plenary lecture of the XVIII B-MRS Meeting given by Prof. Antonio José Roque da Silva (CNPEM, Brazil) on September 24, 2019 at Balneário Camboriú (Brazil).
This document provides an overview of the Institute of Nanoscience and its research activities related to semiconductor nanostructures and their applications. The institute has over 250 researchers studying the fundamental properties and manipulation of nanoscale systems through synthesis, fabrication, experimental and theoretical studies of nanostructures and devices. Key areas of research include semiconductor nanowires for applications in electronics, optoelectronics and spintronics. Heterostructured nanowires of InAs, InSb and InP are investigated for high mobility transistors and terahertz detectors. Strain-driven self-assembly is used to create 3D nanostructures for applications in sensing, energy harvesting and photonics.
This document summarizes research on topological transport in antimony (Sb) quantum wells. Key points include:
1) Sb is predicted to be a topological semimetal or insulator depending on film thickness. Thin Sb films were grown by MBE to suppress bulk conduction and study topological surface states.
2) Magneto-transport measurements on Hall bar devices show weak antilocalization, consistent with topological surface states. Parameters like the phase breaking length are independent of film thickness.
3) A simple two-channel model of surface and bulk conduction quantitatively fits the high field magnetoresistance evolution with decreasing thickness.
Overall the results provide evidence for topological surface states in thin Sb
The document discusses nantennas, which are nanoscopic antennas that can convert solar radiation into electricity. Nantennas address many limitations of traditional photovoltaic cells. They work by absorbing electromagnetic waves from solar radiation and thermal earth radiation. This induces an alternating current in the nantenna, which is then rectified into direct current using a diode. Nantennas show promise for applications like self-charging batteries and could be mass produced inexpensively using roll-to-roll manufacturing. Future research aims to improve rectifier efficiency and upscale the technology for widespread use.
Ph d defense_rajmohan_muthaiah_University_of_oklahoma_07_28_2021Rajmohan Muthaiah
This slide describes the thermal transport in polymers, polymer nanocomposites and semiconductors using molecular dynamics simulations and first principles calculations
MRS Spring 2009 Poster Rare Earth Diffused GaNmoluen
The document discusses research on rare earth (RE)-doped gallium nitride (GaN) films grown via diffusion doping with neodymium (Nd) and erbium (Er). Key findings include:
1) Nd-doped and Er-doped GaN samples exhibited room temperature ferromagnetism and near-infrared luminescence. Emission wavelengths matched telecommunications applications.
2) Increasing silicon doping decreased the ferromagnetic properties, as silicon competes with rare earths for gallium sites. Luminescence intensity was less affected by silicon doping.
3) Annealing time affected luminescence intensity, which increased then decreased with longer annealing, suggesting
Laser trapped mirrors could enable the construction of large, lightweight optical systems in space. A laser traps microscopic particles at the interference fringes created by its reflection between two deflectors, arranging the particles into a reflective mirror surface. Key challenges include maintaining the trap against particle evaporation from infrared background photons and understanding optical binding forces between particles. Further experiments and simulations are needed to evaluate particle design, collective behavior, trap loading and damping mechanisms to develop this technology.
This Presentation is based on our Research work carried out in GNDU Amritsar and DAVIET, Jallandhar. We fabricated Ion track filters; nanowires and some Exotic Patterns for the first time in India using simple Techniques.
Room-temperature emission at telecom wavelengths from silicon photonic crysta...Roberto Lo Savio
Light emission in crystalline silicon is the fundamental goal for the development of an all-silicon device showing efficient infrared emission at room temperature. The exploitation of optically active structural defects that generates sub-bandgap luminescence is the strategy explored here to make silicon an efficient infrared emitter around 1.5 μm.
Radiation and magneticfield effects on unsteady naturalAlexander Decker
This document discusses research on the effects of thermal radiation and magnetic fields on unsteady natural convective flow of nanofluids past an infinite vertical plate with a heat source. The following key points are discussed:
- Governing equations for the unsteady, two-dimensional flow are derived taking into account radiation, magnetic fields, and thermophysical properties of nanofluids.
- The equations are solved numerically using Laplace transform techniques. Parameters like radiation, magnetic field, heat source, and nanoparticle volume fraction are examined.
- It is found that increasing the magnetic field decreases fluid velocity, while radiation, heat source, and nanoparticle volume fraction more strongly influence velocity and temperature profiles. Nanoparticle shape
Radiation and magneticfield effects on unsteady naturalAlexander Decker
This document discusses research on the effects of thermal radiation and magnetic fields on unsteady natural convective flow of nanofluids past an infinite vertical plate with a heat source. The following key points are discussed:
- Governing equations for the unsteady, two-dimensional flow are derived taking into account radiation, magnetic fields, and thermophysical properties of nanofluids.
- The equations are solved numerically using Laplace transform techniques. Parameters like radiation, magnetic field, heat source, and nanoparticle volume fraction are examined.
- It is found that increasing the magnetic field decreases fluid velocity, while radiation, heat source, and nanoparticle volume fraction have a greater influence on fluid velocity and temperature profiles. Nan
This document summarizes Andrew Oles' PhD dissertation on modeling of solar particle receivers for hydrogen production and thermochemical energy storage. It describes particle receivers as a potential next-generation concentrating solar power technology with solid particles as the heat transfer medium. The document outlines the modeling of inert and reactive particle receivers, including simulations of prototype and commercial-scale receivers to analyze performance tradeoffs. Selective absorption in particles is investigated, showing higher efficiencies are possible by tuning infrared emissivity.
Dr. Harold Weinstock presents an overview of his program, Quantum Electronic Solids, at the AFOSR 2013 Spring Review. At this review, Program Officers from AFOSR Technical Divisions will present briefings that highlight basic research programs beneficial to the Air Force.
Greg Smestad, Leonardo Micheli, Thomas Germer, and Eduardo Fernández presented research on characterizing the optical effects of soiling on PV glass and modules. They measured the transmission of glass coupons exposed outdoors at multiple locations over 8 weeks and found soiling reduced transmission more at shorter wavelengths. Particle area coverage on the coupons correlated linearly with reduced hemispherical transmittance. Angular measurements showed soiling impacts transmission more for direct light than hemispherical. The research aims to better understand how soiling impacts PV performance globally.
Optical Characterization of PV Glass Coupons and PV Modules Related to Soilin...Greg Smestad
Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses,
Greg P. Smestad, Ph.D., Sol Ideas Technology Development
December 6th, 2017, 11:35 AM - 12:00 PM
Session 5: Characterization (Chair: Xiaohong Gu, NIST)
Atlas/NIST Workshop on PV Materials Durability
December 5-6, 2017, Gaithersburg, Maryland
National Institute of Standards and Technology, Gaithersburg, Maryland
https://www.nist.gov/el/mssd/agenda
Different types of Nanolithography technique.
Types: Electron beam lithography, Photolithography, electron-beam writing, ion- lithography, X-ray lithography, and related images, concepts and graphical views.
I hope this presentation helpful for you.
https://www.linkedin.com/in/preeti-choudhary-266414182/
https://www.instagram.com/chaudharypreeti1997/
https://www.facebook.com/profile.php?id=100013419194533
https://twitter.com/preetic27018281
Please like, share, comment and follow.
stay connected
If any query then contact:
chaudharypreeti1997@gmail.com
Thanking-You
Preeti Choudhary
Tobias junginger low energy muon spin rotation and point contact tunneling ...thinfilmsworkshop
Muon spin rotation (muSR) and point contact tunneling (PCT) are used since several years for bulk niobium studies. Here we present studies on niobium thin film samples of different deposition techniques (diode, magnetron and HIPIMS) and compare the results with RF measurements and bulk niobium results. It is consistently found from muSR and RF measurements that HIPIMS can be used to produce thin films of high RRR. Hints for magnetic impurities are found on HIPIMS and dcms samples. The Meissner effect is linear on all tested samples.
Sputtering yield and nanopattern formation study of BNSiO2 (Borosil) at eleva...Dr. Basanta Kumar Parida
Lower sputtering yield of the discharge wall material is a crucial parameter for the performance of Hall Effect Thruster (HET) [1, 2]. In this article, we report the sputtering yield of HET wall
material BNSiO2 (borosil) at elevated temperature ~600 °C using quartz crystal microbalance (QCM). We observe a linear increase in the sputtering yield with temperature and it remains stable during long duration experiments using Xe ions. Two different crystallographic orientations of borosil give a
slight variation in the yield. The higher yields for higher operating temperatures is proposed to be due to the thermal spike nature. Microscopic surface morphology shows only different grains of BNSiO2, however high resolution nanoscopic view reveals the formation of nanoripple like structures over different grains [3]. The periodicity of such features increases with ion dose (sputtering time) and temperature in the range of 70-190 nm. Local curvature dependent erosion plays crucial role in such pattern formation [4].
Reference:
1. D.M. Goebel, I. Katz, Fundamentals of Electric Propulsion, Ion and Hall Thrusters, 2008.
2. M. Ranjan, A. Sharma, A. Vaid, T. Bhatt, V. Nandalan, M.G. James, H. Revathi, S. Mukherjee, AIP
Adv. 6 (2016) 95224
3. R. M. Bradley, J.M.E. Harper, J. Vac. Sci. Technol. A 6 (1988) 2390
4. B. K. Parida, Sooraj K P, S. Hans, V. Pachchigar, S. Augustine, Remyamol T, M. R. Ajith, M. Ranjan;
Nucl. Inst and Methods B, 514 (2022) 1-7
Study of size dependence of Raman scattering in Carbon nanotubes.
To Study Temperature dependence of Raman spectra
To Study spatial distribution of temperature during laser processing
To Study Temperature rise in CNTs as a function of laser power
Theoretically calculated Vs Experimental Raman temperature
Plenary lecture of the XVIII B-MRS Meeting given by Prof. Antonio José Roque da Silva (CNPEM, Brazil) on September 24, 2019 at Balneário Camboriú (Brazil).
Similar to 20191028 Wang Seminar at NCTU (Near-field Thermal Radiation) (20)
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
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Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...
20191028 Wang Seminar at NCTU (Near-field Thermal Radiation)
1. Near-field Thermal Radiation for
Thermal Energy Conversion and Heat Modulation
Research Seminar at National Chiao Tung University
Hsinchu, Taiwan, October 29, 2019
Liping Wang, Ph.D.
Associate Professor in Mechanical and Aerospace Engineering
Director of Nano-Engineered Thermal Radiation Laboratory
School for Engineering of Matter, Transport & Energy
Arizona State University, Tempe, AZ USA
http://faculty.engineering.asu.edu/lpwang
Email: liping.wang@asu.edu
2. 2
Nano-Engineered Thermal Radiation Group
Phoenix, AZ
² 5th largest city in US with population ~1.7 million (2018)
² Abundant solar radiation: ~300 days sunshine /year
² Average temp.: summer >35degC, winter ~10degC
² < 5 hr driving to Los Angeles, San Diego, Las Vegas
² 5 hr driving to Grand Canyon and other national parks
² 2 hr driving to Flagstaff AZ (Ski resort, Indian habitat)
² ASU is Located in Tempe, Arizona, USA, southeast in the
Phoenix Metro Area with Intel, Freescale, etc
o Phoenix, AZ
ASU
3. 3
Nano-Engineered Thermal Radiation Group
ASU’s strong commitment to solar energy
Total Solar Generation Capacity: 24.1 MW (50% ASU daytime peak load)
(PV: 21.8 MW; Solar thermal: 13,908 MMBTUs = 2.3 MW equivalent)
Total Solar Systems: 89
Total Number of PV Panels Installed: 81,424
Total Number of CPV Modules Installed: 8,652
Total Number of Solar Collectors Installed: 9,280
Total Number of Shaded Parking Spaces: 5,952
http://about.asu.edu, https://cfo.asu.edu/solar
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5. 5
Nano-Engineered Thermal Radiation Group
Outline
1. Background
• Near-field thermal radiation and its potential applications
• Literature review – theoretical studies by Wang group
• Literature review – recent experiments by other groups
2. Super-Planckian Near-field Thermal Radiation Measurements
• Al thin films with nanoparticles as vacuum gap spacers
• Heavily-doped Si with polymer posts and in-situ gap determination
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
• Graphene characterization
• Theoretical prediction
• Preliminary experimental results
4. Future Work and Acknowledgments
6. Nano-Engineered Thermal Radiation Group
far field vs. near field
2
T
12
q¢¢
1
T
d
l evanescent wave
2
T
12
q¢¢
1
T
d
Subject to blackbody radiation
4 4
12 1 2
( )
q T T
es
¢¢ = -
Far field (d >> l):
Coupling of evanescent waves
Near field (d < l):
Near-field heat transfer
enhancement
1. Background
6
Liu, Wang and Zhang, Nanosc. Microsc. Therm. 19, 98 (2015)
What is near-field thermal radiation?
7. 7
Nano-Engineered Thermal Radiation Group Liu, Wang and Zhang, Nanosc. Microsc. Therm. 19, 98 (2015)
Near-field radiation applications
1. Background
8. 8
Nano-Engineered Thermal Radiation Group
Near-field thermophotovoltaic energy conversion (by Wang Group)
Metallodielectric
Near-Field TPV Emitter
Near-field TPV cell
with Back Reflector
Tungsten Nanowire-
based HMM Near-
field TPV Emitter
Chang, Yang, and Wang*,
IJHMT 87, 237 (2015)
Bright, Wang, and Zhang,
J. Heat. Transfer. 134, 062701(2014)
Yang, Chang, and Wang*,
JHT 139, 052701 (2015)
Nanostructured MM
Near-Field TPV Emitter
Sabbaghi, Yang, and Wang*,
JQSRT (2019)
1. Background
9. Nano-Engineered Thermal Radiation Group
5
10
15
20
330 335 340 345 350
Insulating VO
2
Metallic VO
2
VO
2
Emitter Temperature, T
H
(K)
Net
Heat
Flux,
q"
(kW/m
2
)
d = 50 nm
T
L
= 300 K
"ON"
"OFF" 10
3
10
4
10
5
10
6
0.5
1
1.5
2
10
1
10
2
10
3
forward heat flux
reverse heat flux
rectification factor
Net
Heat
Flux,
q''
(W/m
2
)
Rectification
Factor,
R
Vacuum Gap, d (nm)
Near-field Radiative Heat Flux
Near-Field
Thermal Modulator
Near-field
Thermal Switch
Yang, Basu, and Wang,
APL 103, 163101 (2013)
Yang and Wang,
JQSRT 197, 65-75 (2017)
Yang, Basu and Wang,
JQSRT 158, 69 (2015)
Near-field
Thermal Rectifier
Near-field radiative heat control (by Wang group)
1. Background
9
10. Nano-Engineered Thermal Radiation Group 10
• NFR between doped Si of 1×1 cm2
• d = 200 to 780 nm, DT= 2 to 30 K
• Using SiO2 posts
• 11 times as high as blackbody limit
• Bow reduction is done by depositing silicon
dioxide at 300 K
• Using FTIR to measure the reflectance to quantify
the gap spacing
Watjen et al. Applied Physics Letters, 2016
Bernardi et al. Nature Communications, 2016
• NFR between two glass surfaces
• d = 1 µm, Th= 323 K, Tc= 297 K
• Small polystyrene microsphere (80 particles)
• Exceeding the blackbody as the gap decreases
below 5 µm
Hu et al. Applied Physics Letters, 2008
• Radiative heat flux between two 5×5 mm2
Si surfaces;
• d = 150 nm and DTmax= 120 K;
• Using SU-8 with a 3.5 µm height and SiO2
stopper with a 150 nm height;
• Calibrated masses ranging from 0.9 to 5g;
• Exceeding the blackbody by 8.4 times;
• Enhancement only due frustrated modes.
Recent experimental NFR
1. Background
11. Nano-Engineered Thermal Radiation Group 11
Recent experimental NFR
• Radiative heat flux between 5×5 mm2
quartz plates
• Minimum gap of 200 nm
• Maximum temperature difference of
156 K
• Exceeding the blackbody by 40 times
at d = 200 nm
Ghashami et al., Phys. Rev. Lett. 2018
• Radiative heat flux between metallo-
dielectric (MD) multilayers (Ti / MgF2)
at nanoscale gaps
• Surface plasmon polaritons supported
at multiple metal-dielectric interfaces
• Minimum gap of 160 nm
• Exceeding the blackbody by 7 times at
d = 160 nm
Lim et al., Nature Commun. 2018
Fiorino et al., Nano Letters, 2018
• NFR between planar silica surfaces
• Separated by gaps as small as 25 nm
• 1200-fold enhancement with respect
to far field
• 700-fold enhancement over black
body limit
1. Background
12. Nano-Engineered Thermal Radiation Group 12
Recent experimental NFR
Shi et al.,
Nano Letters
2015
Hyperbolic
Metamaterials
NFR in nm and
sub-nm gaps
Cui et al.,
Nature Commun.
2016
1. Background
13. Nano-Engineered Thermal Radiation Group
2. Super-Planckian Near-field Thermal Radiation Measurements
Al thin films – setup with PS nanoparticles as spacer
Sabbaghi et al., PR Applied, in revision (available on arXiv) 13
14. Nano-Engineered Thermal Radiation Group
Al thin films – gap fitting with Si measurement
Sabbaghi et al., PR Applied, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
14
15. Nano-Engineered Thermal Radiation Group
Al thin films – comparison between measurement and theory
Sabbaghi et al., PR Applied, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
15
16. Nano-Engineered Thermal Radiation Group
Al thin films – near field enhancement over far field
Sabbaghi et al., PR Applied, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
16
17. Nano-Engineered Thermal Radiation Group
Heavily doped Si – vacuum gap created by patterned SU-8 posts
Wafer pre-treatment
SU-8 coating
Post-baking
Posts pattern
exposure
Height calibration
pattern exposure
Pre-baking
Post-baking
Same
Spin
Speed
Microscopic image
of SU-8 post
Thickness of SU-8
under profilometer
Wafer pre-treatment
SU-8 coating
Post-baking
Posts pattern
exposure
Height calibration
pattern exposure
Pre-baking
Post-baking
Same
Spin
Speed
Microscopic image
of SU-8 post
Thickness of SU-8
under profilometer
Anisotropic plasma
dry etching
Anisotropic plasma
dry etching
Ying et al., ACS Photonics, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
17
18. Nano-Engineered Thermal Radiation Group
Heavily doped Si – thermal measurement setup
Ying et al., ACS Photonics, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
18
19. Nano-Engineered Thermal Radiation Group
Heavily doped Si – vacuum gap determined by capacitance method
Ying et al., ACS Photonics, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
19
20. Nano-Engineered Thermal Radiation Group
Heavily doped Si – measured near-field radiative flux
Ying et al., ACS Photonics, in revision (available on arXiv)
2. Super-Planckian Near-field Thermal Radiation Measurements
20
21. Nano-Engineered Thermal Radiation Group 21
C-V Measurement
Purchased from Graphenea.com
• Graphene: monolayer, transferred from CVD
• SiO2: 300 nm thermal oxide (ed = 3.8)
• Doped Si: r<0.005 ohm·cm
• Size: 1 cm x 1 cm
https://www.graphenea.com/
𝐶! =
"!""#
$!
=11.2 nF
Electrically gating graphene
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
22. Nano-Engineered Thermal Radiation Group 22
Vg < Vcnp
Vg = Vcnp
Vg > Vcnp
Ω
R – V Measurement
Determination of charge neutrality point (CNP)
Vcnp = 90 V
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
23. Nano-Engineered Thermal Radiation Group 23
(1-R)
/
(1-R
cnp
)
Measurement Modeling
(1-R)
/
(1-R
cnp
)
Graphene: 0.345 nm
SiO2: 300 nm
Doped Si: 525 um
FTIR measurement with electrical gating
• Spectral reflectance is measured due to opaqueness
• Lowest absorption is observed at Vg = Vcnp = 80V, or µ = 0
• Absorption increased when Vg is away from Vcnp
• Consistent with modeling
|Vg – VCNP|
80V
0V
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
24. Nano-Engineered Thermal Radiation Group 24
Fermi level vs. Gating voltage
𝜇 = ℎ𝑣% ⁄
𝜋𝐶! 𝑉
! − 𝑉
&'( (𝐴𝑒)
where vF = 1.1 x 106 m/s
Falkovsky et al., J. Phys. 129, 012004 (2008)
G G G 0
/ ( )
i t
e s we
=
σG
= f (µ,T,ω),
Electrical Permittivity:
where
Predicted gating voltage (Vg) effect on graphene properties
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
25. Nano-Engineered Thermal Radiation Group
( ) ( ) ( )
1 2
2
0 0 0
1
( ) , , ,
4
w w w w w bx w b b
p
¥ ¥ ¥
¢¢ = = Q -Q
é ù
ë û
ò ò ò
q q d d T T d
( )
( )( ) ( )( )
( )
( ) ( )
( ) ( )
0 0
0 0
0 0
2 2 2 2
012 034 012 034
2 2
2 2
012 034 012 034
2Im 2Im
012 034 012 034
2 2
2 2
012 034 012 034
,
exp( / ) 1
1 1 1 1
( , )
1 1
4Im( )Im 4Im( )Im
,
1 1
B
s s p p
prop
i d i d
s s p p
d d
s s p p
evan
i d i d
s s p p
T
k T
r r r r
r r e r r e
r r e r r e
r r e r r e
g g
g g
g g
w
w
w
x w b
x w b
- -
Q =
-
- - - -
= +
- -
= +
- -
!
!
ì
ï
ï
ï
ï
ï
í
ï
ï
ï
ï
ï
î
2 2
2 2
2
02 12
012 2
02 12
1
i t
i t
r r e
R
r r e
g
g
+
=
+
2 2
2 2
2
02 12
012 2
02 12
1
i t
i t
t t e
T
r r e
g
g
=
+
( ) ( )
( ) ( )
2 2
2 2
2 0 2 0 0
20
2 0 2 0 0
2 0 0 2
20
2 0 0 2
/
/
p p
p
p p
s s
s
s s
r
r
e g g s g g we
e g g s g g we
g g µ s w
g g µ s w
ì - +
ï =
+ +
ï
í
ï - -
=
ï
+ +
î
SiO2
Doped Si
Doped Si
1
2
3
4
d
0
t2
t3
k
β
γ
NFR calculation for graphene
SiO2
where
Thin-film optics with surface currents:
where
• Graphene modelled
as surface current
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
25
26. Nano-Engineered Thermal Radiation Group 26
emitter receiver
Predicted NFR heat flux without gating (Vg = 0)
Heat
flux,
q
(W/m
2
)
Vacuum distance d = 200 nm
Vcnp = 80 V
qBB = 1 kW/m2
for ∆T = 100∘C
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
27. 27
Nano-Engineered Thermal Radiation Group
80 V
0 V
80 V
0 V
80 V
0 V
200 nm
350 nm
500 nm
• Greater tuning at smaller gap distance
Predicted NFR heat flux modulation with gating
Doped Si
Doped Si
Emitter at T1
Graphene
(ungated)
Graphene
(gated w/ Vg)
SiO2
SiO2
Receiver at T2
|Vg – VCNP|
Heat
flux,
q
(W/m
2
)
Vcnp = 80 V
qBB = 1 kW/m2
for ∆T = 100∘C
3. Gate-tunable Near-field Radiative Heat Flux with Graphene
29. Nano-Engineered Thermal Radiation Group
Ongoing and Future Work
Plate-Plate tunable NFR devices
graphene, VO2, etc
d > 100 nm
Tip-surface NFR
2D materials
d ~ nm
Sphere-plate NFR
metasurfaces, 2D materials
d > 30 nm
(DURIP Award)
29
30. 30
Nano-Engineered Thermal Radiation Group
Acknowledgements
Team Players:
o Dr. Yue Yang (2016-2012, currently Assistant Professor at Harbin Institute of Technology, Shenzhen)
o Dr. Hao Wang (2016-2012, currently postdoc at Lawrence Berkeley National Lab)
o Dr. Jui-Yung Chang (2017-2012, currently Assistant Professor at National Chiao Tung Univ., Taiwan)
o Dr. Hassan Alshehri (2018 – 2014, currently Assistant Professor at King Saud University, Saudi Arab)
o Dr. Linshuang Long (3rd year postdoc, VO2 metamaterial and graphene metasurface)
o Dr. Qing Ni (3rd year postdoc, TPV measurement and ultrathin cells)
o Mr. Payam Sabbaghi (5th year PhD student, near-field TPV and near-field radiation measurement)
o Ms. Sydney Taylor (4th year PhD student, NASA NSTRF Fellow, VO2 fab and metafilm)
o Ms. Xiaoyan Ying (3rd year PhD student, near-field radiation measurement and 2D materials)
o MS and UG students: Ramteja Kondakindi, Ryan McBurney, Lee Lambert, Niko Vlastos, etc