Copper (775) - an optics, 2PPE, and Bulk state simulation studyPo-Chun Yeh
My earlier studies on Cu(775) - a tilt cut highly crystalline copper surface using ultrafast femtosecond laser based 2-photon photoemission and its related simulation via Fortran 77.
Space Radiation Superconductive Shield (SR2S) is an EU funded FP7 project which is researching new technology to protect astronauts in space from radiation. On 9th April 2014 in Torino, Italy, SR2S held their first conference to give an update on the project so far.
For more information visit:
www.sr2s.eu
Twitter - @SR2SMars
This research, presented at the 2014 APS March Meeting in Denver, Colorado, characterizes magnetic phase transitions in the manganese-doped dichalcogenide TaS2.
- The document describes an add-on setup for making bifacial PV cell measurements in a Berger flasher system using two mirrors to direct light to the rear side of the cell.
- Key characteristics of the setup are that it provides front and rear illumination at up to 1.5 suns intensity levels, maintains constant cell temperature, and uses a reference cell to correct for intensity fluctuations.
- Initial measurements showed the setup could fulfill IEC flasher measurement criteria except for spatial homogeneity, and was suitable for investigating differences between bifacial cell designs.
The document reports on an ARPES microscopy study of free-standing bilayer graphene. Key findings include:
1) Bilayer graphene samples were prepared by mechanical exfoliation on 5μm wells and studied using ARPES microscopy between 110-300K.
2) Analysis of ARPES data using a tight-binding model found the Fermi velocity to be 1.003-1.042×106 m/s, interlayer asymmetry Δ/2 = 48-56 meV, and interlayer coupling γ1 = 0.6-0.611 eV.
3) Additional trilayer graphene was studied at room temperature using a 74eV photon energy, showing a doped sample with a 350
This document discusses the use of superconductive magnetic shielding for radiation protection on exploration missions. It describes the radiation risks faced during long-duration space travel and proposes active magnetic shielding as a solution. Magnetic shield configurations like toroidal and solenoidal fields are examined, with previous modeling showing a racetrack toroid could provide effective shielding against galactic cosmic rays if its magnetic field strength and radius products reach approximately 15 Tm. Mechanical and structural design challenges for magnet systems in space are also addressed.
The document summarizes the design evaluation results for a gamma ray incidence detector housing for a CubeSat mission. Key features of the new design include cork insulation sleeves for thermal insulation and vibration dampening, an internal PCB for signal amplification isolation, and a ceramic interface to electrically isolate the housing from the satellite structure. Testing showed the design met requirements for the satellite's temperature and vibration ranges to ensure proper detector performance during the EXACT mission to study solar flares and measure photon time arrivals.
Effects of ionizing radiation on the layered semiconductor tungsten diselenideRoger Walker
This document summarizes research on the effects of ionizing radiation on tungsten diselenide (WSe2), a two-dimensional material with potential applications in space electronics. The research examined how WSe2 is impacted by exposure to x-rays, electrons, protons at different energies, and heavy metal ions like iron and silver. It was found that thin films of WSe2 grown via MOCVD were stable against soft x-rays, but exfoliated WSe2 ionized in response to protons and was destabilized by heavy metal ions. The band alignment of WSe2 on silicon carbide substrates was also modified by ionization. Exposure to air led to oxidation of WSe2 damaged by
Copper (775) - an optics, 2PPE, and Bulk state simulation studyPo-Chun Yeh
My earlier studies on Cu(775) - a tilt cut highly crystalline copper surface using ultrafast femtosecond laser based 2-photon photoemission and its related simulation via Fortran 77.
Space Radiation Superconductive Shield (SR2S) is an EU funded FP7 project which is researching new technology to protect astronauts in space from radiation. On 9th April 2014 in Torino, Italy, SR2S held their first conference to give an update on the project so far.
For more information visit:
www.sr2s.eu
Twitter - @SR2SMars
This research, presented at the 2014 APS March Meeting in Denver, Colorado, characterizes magnetic phase transitions in the manganese-doped dichalcogenide TaS2.
- The document describes an add-on setup for making bifacial PV cell measurements in a Berger flasher system using two mirrors to direct light to the rear side of the cell.
- Key characteristics of the setup are that it provides front and rear illumination at up to 1.5 suns intensity levels, maintains constant cell temperature, and uses a reference cell to correct for intensity fluctuations.
- Initial measurements showed the setup could fulfill IEC flasher measurement criteria except for spatial homogeneity, and was suitable for investigating differences between bifacial cell designs.
The document reports on an ARPES microscopy study of free-standing bilayer graphene. Key findings include:
1) Bilayer graphene samples were prepared by mechanical exfoliation on 5μm wells and studied using ARPES microscopy between 110-300K.
2) Analysis of ARPES data using a tight-binding model found the Fermi velocity to be 1.003-1.042×106 m/s, interlayer asymmetry Δ/2 = 48-56 meV, and interlayer coupling γ1 = 0.6-0.611 eV.
3) Additional trilayer graphene was studied at room temperature using a 74eV photon energy, showing a doped sample with a 350
This document discusses the use of superconductive magnetic shielding for radiation protection on exploration missions. It describes the radiation risks faced during long-duration space travel and proposes active magnetic shielding as a solution. Magnetic shield configurations like toroidal and solenoidal fields are examined, with previous modeling showing a racetrack toroid could provide effective shielding against galactic cosmic rays if its magnetic field strength and radius products reach approximately 15 Tm. Mechanical and structural design challenges for magnet systems in space are also addressed.
The document summarizes the design evaluation results for a gamma ray incidence detector housing for a CubeSat mission. Key features of the new design include cork insulation sleeves for thermal insulation and vibration dampening, an internal PCB for signal amplification isolation, and a ceramic interface to electrically isolate the housing from the satellite structure. Testing showed the design met requirements for the satellite's temperature and vibration ranges to ensure proper detector performance during the EXACT mission to study solar flares and measure photon time arrivals.
Effects of ionizing radiation on the layered semiconductor tungsten diselenideRoger Walker
This document summarizes research on the effects of ionizing radiation on tungsten diselenide (WSe2), a two-dimensional material with potential applications in space electronics. The research examined how WSe2 is impacted by exposure to x-rays, electrons, protons at different energies, and heavy metal ions like iron and silver. It was found that thin films of WSe2 grown via MOCVD were stable against soft x-rays, but exfoliated WSe2 ionized in response to protons and was destabilized by heavy metal ions. The band alignment of WSe2 on silicon carbide substrates was also modified by ionization. Exposure to air led to oxidation of WSe2 damaged by
This document summarizes an ARPES and SPE-LEEM study on supported, suspended, and twisted bilayer MoS2. The study directly measures the MoS2 band structure using SPE-LEEM to study the band gap transition and role of interlayer coupling in monolayer, bilayer, and twisted bilayer MoS2. It also studies the substrate effect by examining suspended MoS2. Preliminary results on effective mass and spin-orbit splitting are also presented.
Joe Kelleher Presentation (May 27th 2014)Roadshow2014
The document discusses using neutrons for in-situ observation of engineering material behavior. It describes the ENGIN-X beamline at ISIS, which allows for various types of in-situ experiments including mechanical deformation, heat treatment, and phase transformations. Examples are given of experiments involving in-situ heat treatment, cyclic electric fields on ferroelectrics, welding, and fatigue crack growth. Practical considerations for in-situ neutron experiments and opportunities for future directions are also outlined.
Characterization of the electrical properties of interfaces by impedance spec...Edmund Mills
Summary of major research accomplishments during PhD. Emphasizes my most recent work: the development of a new method for the determination of Peukert's constant, and the demonstration of the utility of Peukert's equation for the analysis of supercapacitor performance.
The driving engine for the exponential growth of digital information processing systems is scaling down the transistor dimensions. For decades, this has enhanced the device performance and density. However, the International Technology Roadmap for Semiconductors (ITRS) states the end of Moore’s law in the next decade due to the scaling challenges of silicon-based CMOS electronics, e.g. extremely high power density. The forward-looking solutions are the utilization of emerging materials and devices for integrated circuits, e.g. carbon-based materials. The presentation of my Ph.D. work focuses on graphene, one atomic layer of carbon sheet, experimentally discovered in 2004. Since fabrication technology of emerging materials is still in early stages, transistor modeling has been playing an important role for evaluating futuristic graphene-based devices and circuits. The device has been simulated by solving a quantum transport model based on non-equilibrium Green’s function (NEGF) approach, which fully treats short channel-length electrostatic effects and the quantum tunneling effects, leading to the technology exploration of graphene nanoribbon field effect transistors (GNR FETs) for the future. This research presents a comprehensive study of the width-dependence performance of the GNR FETs and the scaling of its channel length down to 2.5 nanometer, investigating its potential use beyond-CMOS emerging technology.
1) The document summarizes the synthesis and characterization of the ferroelectric material barium strontium titanate (Ba1-xSrxTiO3 or BST) through solid state and sol-gel methods.
2) Key characterization techniques discussed are X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and dielectric measurement through impedance spectroscopy.
3) Results shown include XRD patterns demonstrating phase composition and structure of BST samples with varying strontium content, as well as frequency-dependent dielectric properties such as real and imaginary permittivity and loss tangent.
The document discusses graphene and its potential use in transistors. It describes graphene as a single sheet of carbon atoms arranged in a honeycomb lattice. Researchers have shown that stacking a few layers of graphene could enable optical switches that are 100 times faster than current technologies. The document also details experiments where graphene field-effect transistors were fabricated with gate lengths down to 150nm, achieving a cutoff frequency of 26GHz. Scaling to smaller gate lengths allows higher frequencies, with cutoff frequency scaling inversely with the square of the gate length. Graphene has potential for high-frequency and versatile applications due to its high carrier mobility and small channel lengths.
This document summarizes several experiments measuring out-of-equilibrium transport in oxide materials. It focuses on measurements using conducting atomic force microscopy (AFM) and electrostatic force microscopy (EFM) to study the metal-insulator transition in vanadium dioxide (VO2) thin films at the nanoscale. In conducting AFM mode, current switching was observed in local I-V curves, indicating a transition between metallic and insulating states. EFM detected random telegraphic noise in VO2 at room temperature, suggesting many-body effects are involved in the transition absent Joule heating effects.
This doctoral dissertation examines the use of reduced graphene oxide and its composites for various energy applications. The document outlines the synthesis of reduced graphene oxide through chemical reduction of graphene oxide. Characterization shows the reduced graphene oxide has a layered morphology. The dissertation discusses using reduced graphene oxide composites with materials like ZnO, Ag, and Ag2O as electron transport layers to improve dye-sensitized solar cell performance. Reduced graphene oxide is also investigated as a counter electrode material for dye-sensitized solar cells. Additionally, the potential of reduced graphene oxide composites with polymers and metal oxides for supercapacitors, lithium-ion batteries, and electromagnetic interference shielding is reviewed. Specific applications demonstrated include a reduced graphene oxide
Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems...Pawan Kumar
This document provides supporting information for a research article on flexible and ultra-soft inorganic semiconductor systems based on tin(II) iodide (SnIP). It includes details from quantum chemical calculations and experimental measurements that characterize the mechanical and structural properties of individual SnIP nanowires. Density functional theory calculations determine the phonon dispersion relations and Raman modes of SnIP under pressure. Experimental force-distance spectroscopy on suspended SnIP nanowires measures the Young's modulus, finding values around 190 GPa along the wire direction. High-pressure x-ray diffraction data and Rietveld refinement are used to calculate the bulk modulus of SnIP as 14.87 GPa, characterizing its compressibility.
This document provides information on radioactivity and radioactive isotopes used in clinical medicine. It discusses the properties of natural and artificial radioactivity and types of radioactive decay. Common medical radioisotopes used for therapy and diagnosis like radium-226, cesium-137, cobalt-60, iridium-192, gold-198, and iodine-125 are described in terms of their production, half-lives, emissions, and clinical applications and source forms. The ideal properties of radioisotopes for use in teletherapy and brachytherapy are also summarized.
This document discusses graphene MOSFETs and their potential for post-silicon electronics. It summarizes that graphene has zero bandgap, which prevents switching, but the bandgap can be modified through nanoribbons, bilayers, or strain. Graphene MOSFETs have been fabricated with exfoliated or epitaxial graphene using various dielectrics and show high mobility but low on-off ratios. While graphene's properties are promising for high-speed devices, opening a bandgap comparable to silicon would decrease mobility and hinder low-power applications. Overall, graphene transistors continue to be explored but challenges remain for practical logic devices to replace silicon MOSFETs.
Noble Metal Free, Visible Light Driven Photocatalysis Using TiO2 Nanotube Arr...Pawan Kumar
Bulk g-C3N4 is an earth-abundant, easily synthesizable, and exceptionally stable photocatalyst with an electronic bandgap of 2.7 eV. Herein, the concepts of P-doping and size quantization are combined to synthesize highly fluorescent P-doped carbon nitride quantum dots (CNPQDs) with a bandgap of 2.1 eV. CNPQDs are hosted on anatase-phase and rutile-phase TiO2 nanotube array scaffolds, and examined as photoanodes for sunlight-driven water-splitting and as photocatalysts for surface catalytic reactions. Square-shaped rutile phase TiO2 nanotube arrays (STNAs) decorated with CNPQDs (CNPQD-STNA) generate 2.54 mA cm−2 photocurrent under AM1.5 G simulated sunlight. A champion hydrogen evolution rate of 22 µmol h−1 corresponds to a Faradaic efficiency of 93.2%. In conjunction with Ag nanoparticles (NPs), the CNPQD-STNA hybrid is also found to be an excellent plexcitonic photocatalyst for the visible light-driven transformation of 4-nitrobenzenethiol (4-NBT) to dimercaptoazobenzene (DMAB), producing reaction completion at a laser power of 1 mW (532 nm) while Ag NP/TNA and Ag NP/STNA photocatalysts cannot complete this transformation even at 10 mW laser power. The results point the way forward for photochemically robust, noble metal free, visible light harvesting photoacatalysts based on nanostructured heterojunctions of graphenic frameworks with TiO2.
Gamry’s eQCM 10M™ is a rapid, impedance-scanning electrochemical quartz crystal microbalance (EQCM) that adds a valuable tool in the analytical toolbox of anyone investigating interfacial processes.
A few Curious Aspects of ZnO Nanostructures - Prof.Joy MitraSTS FORUM 2016
This document summarizes research on designing defects in ZnO nanostructures. It discusses how ZnO naturally forms with n-type doping due to oxygen vacancies and zinc interstitials. The researcher investigates controlling the ratio of zinc interstitials to oxygen vacancies to tune the material's optical and electrical properties. Photoluminescence and conductive atomic force microscopy experiments on ZnO nanorods with varying defect concentrations show changes in emission spectra and localized photoresponse correlated with grain structure. The findings provide insight into defect engineering of ZnO for optoelectronic applications.
Plenary lecture given by Prof. Katsuhiko Ariga (WPI-MANA, NIMS and University of Tokyo, Japan) on September 12, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting.
In the focus of attention at the present time are the new rare earth‐cobalt‐based magnet alloys. This paper is primarily a qualitative review of the physical phenomena controlling their behavior and of the materials problems these magnets have posed. It also provides an outlook at possibilities for the development of still better or cheaper permanent magnets which current research on rare earth‐ transition metal alloys appears to provide. The origins of the magnetic moments and the crystal anisotropy of rare earth‐transition metal phases are discussed. Alternative concepts of the causes of coercivity in powders and sintered bodies are analyzed. Some basic aspects of the sintering of R‐Co compacts and the magnetic hardening of R–Co–Cu alloys in the massive state are reviewed. Specific problems related to particular alloys and applications of the magnets are pointed out. The conclusion is drawn that the new family of permanent magnets now emerging rivals in complexity both the Alnicos and the ferrites together. There are many development opportunities for the future, and we can expect that, eventually, magnets based on high‐anisotropy alloys containing rare earths will be offered in a variety of grades, covering a wide range of properties and prices, and that they will be produced by several drastically different methods.
Primary results or synthesis and characteristics of thin-film materials for PV converters. Work performed by 4-point-probe method, Hall effect, magnetron sputtering, electron microscopy.
Rare-earth nitrides such as GdN, SmN, and EuN are intrinsic ferromagnetic semiconductors that show promise for spintronic applications. Epitaxial thin films of these materials were grown with controlled stoichiometry and doping levels. GdN exhibits ferromagnetism below 70K with carrier-mediated exchange possibly enhancing its Curie temperature above 200K. SmN orders ferromagnetically below 27K despite having a net magnetic moment of zero, while EuN displays unexpected ferromagnetism below 25K likely due to Eu vacancies. Further studies of the electronic band structures and tunable magnetic and transport properties of these rare-earth nitrides could lead to new spintronic and
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.
The document discusses neutrino oscillations and the T2K experiment. It provides a brief history of neutrino discoveries and outlines the current neutrino oscillation model. The T2K experiment uses a neutrino beam produced at J-PARC that travels 295 km to the Super-Kamiokande detector. Recent T2K results and future prospects are discussed. The document raises several open questions in neutrino physics that ongoing experiments hope to address.
This document summarizes an ARPES and SPE-LEEM study on supported, suspended, and twisted bilayer MoS2. The study directly measures the MoS2 band structure using SPE-LEEM to study the band gap transition and role of interlayer coupling in monolayer, bilayer, and twisted bilayer MoS2. It also studies the substrate effect by examining suspended MoS2. Preliminary results on effective mass and spin-orbit splitting are also presented.
Joe Kelleher Presentation (May 27th 2014)Roadshow2014
The document discusses using neutrons for in-situ observation of engineering material behavior. It describes the ENGIN-X beamline at ISIS, which allows for various types of in-situ experiments including mechanical deformation, heat treatment, and phase transformations. Examples are given of experiments involving in-situ heat treatment, cyclic electric fields on ferroelectrics, welding, and fatigue crack growth. Practical considerations for in-situ neutron experiments and opportunities for future directions are also outlined.
Characterization of the electrical properties of interfaces by impedance spec...Edmund Mills
Summary of major research accomplishments during PhD. Emphasizes my most recent work: the development of a new method for the determination of Peukert's constant, and the demonstration of the utility of Peukert's equation for the analysis of supercapacitor performance.
The driving engine for the exponential growth of digital information processing systems is scaling down the transistor dimensions. For decades, this has enhanced the device performance and density. However, the International Technology Roadmap for Semiconductors (ITRS) states the end of Moore’s law in the next decade due to the scaling challenges of silicon-based CMOS electronics, e.g. extremely high power density. The forward-looking solutions are the utilization of emerging materials and devices for integrated circuits, e.g. carbon-based materials. The presentation of my Ph.D. work focuses on graphene, one atomic layer of carbon sheet, experimentally discovered in 2004. Since fabrication technology of emerging materials is still in early stages, transistor modeling has been playing an important role for evaluating futuristic graphene-based devices and circuits. The device has been simulated by solving a quantum transport model based on non-equilibrium Green’s function (NEGF) approach, which fully treats short channel-length electrostatic effects and the quantum tunneling effects, leading to the technology exploration of graphene nanoribbon field effect transistors (GNR FETs) for the future. This research presents a comprehensive study of the width-dependence performance of the GNR FETs and the scaling of its channel length down to 2.5 nanometer, investigating its potential use beyond-CMOS emerging technology.
1) The document summarizes the synthesis and characterization of the ferroelectric material barium strontium titanate (Ba1-xSrxTiO3 or BST) through solid state and sol-gel methods.
2) Key characterization techniques discussed are X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and dielectric measurement through impedance spectroscopy.
3) Results shown include XRD patterns demonstrating phase composition and structure of BST samples with varying strontium content, as well as frequency-dependent dielectric properties such as real and imaginary permittivity and loss tangent.
The document discusses graphene and its potential use in transistors. It describes graphene as a single sheet of carbon atoms arranged in a honeycomb lattice. Researchers have shown that stacking a few layers of graphene could enable optical switches that are 100 times faster than current technologies. The document also details experiments where graphene field-effect transistors were fabricated with gate lengths down to 150nm, achieving a cutoff frequency of 26GHz. Scaling to smaller gate lengths allows higher frequencies, with cutoff frequency scaling inversely with the square of the gate length. Graphene has potential for high-frequency and versatile applications due to its high carrier mobility and small channel lengths.
This document summarizes several experiments measuring out-of-equilibrium transport in oxide materials. It focuses on measurements using conducting atomic force microscopy (AFM) and electrostatic force microscopy (EFM) to study the metal-insulator transition in vanadium dioxide (VO2) thin films at the nanoscale. In conducting AFM mode, current switching was observed in local I-V curves, indicating a transition between metallic and insulating states. EFM detected random telegraphic noise in VO2 at room temperature, suggesting many-body effects are involved in the transition absent Joule heating effects.
This doctoral dissertation examines the use of reduced graphene oxide and its composites for various energy applications. The document outlines the synthesis of reduced graphene oxide through chemical reduction of graphene oxide. Characterization shows the reduced graphene oxide has a layered morphology. The dissertation discusses using reduced graphene oxide composites with materials like ZnO, Ag, and Ag2O as electron transport layers to improve dye-sensitized solar cell performance. Reduced graphene oxide is also investigated as a counter electrode material for dye-sensitized solar cells. Additionally, the potential of reduced graphene oxide composites with polymers and metal oxides for supercapacitors, lithium-ion batteries, and electromagnetic interference shielding is reviewed. Specific applications demonstrated include a reduced graphene oxide
Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems...Pawan Kumar
This document provides supporting information for a research article on flexible and ultra-soft inorganic semiconductor systems based on tin(II) iodide (SnIP). It includes details from quantum chemical calculations and experimental measurements that characterize the mechanical and structural properties of individual SnIP nanowires. Density functional theory calculations determine the phonon dispersion relations and Raman modes of SnIP under pressure. Experimental force-distance spectroscopy on suspended SnIP nanowires measures the Young's modulus, finding values around 190 GPa along the wire direction. High-pressure x-ray diffraction data and Rietveld refinement are used to calculate the bulk modulus of SnIP as 14.87 GPa, characterizing its compressibility.
This document provides information on radioactivity and radioactive isotopes used in clinical medicine. It discusses the properties of natural and artificial radioactivity and types of radioactive decay. Common medical radioisotopes used for therapy and diagnosis like radium-226, cesium-137, cobalt-60, iridium-192, gold-198, and iodine-125 are described in terms of their production, half-lives, emissions, and clinical applications and source forms. The ideal properties of radioisotopes for use in teletherapy and brachytherapy are also summarized.
This document discusses graphene MOSFETs and their potential for post-silicon electronics. It summarizes that graphene has zero bandgap, which prevents switching, but the bandgap can be modified through nanoribbons, bilayers, or strain. Graphene MOSFETs have been fabricated with exfoliated or epitaxial graphene using various dielectrics and show high mobility but low on-off ratios. While graphene's properties are promising for high-speed devices, opening a bandgap comparable to silicon would decrease mobility and hinder low-power applications. Overall, graphene transistors continue to be explored but challenges remain for practical logic devices to replace silicon MOSFETs.
Noble Metal Free, Visible Light Driven Photocatalysis Using TiO2 Nanotube Arr...Pawan Kumar
Bulk g-C3N4 is an earth-abundant, easily synthesizable, and exceptionally stable photocatalyst with an electronic bandgap of 2.7 eV. Herein, the concepts of P-doping and size quantization are combined to synthesize highly fluorescent P-doped carbon nitride quantum dots (CNPQDs) with a bandgap of 2.1 eV. CNPQDs are hosted on anatase-phase and rutile-phase TiO2 nanotube array scaffolds, and examined as photoanodes for sunlight-driven water-splitting and as photocatalysts for surface catalytic reactions. Square-shaped rutile phase TiO2 nanotube arrays (STNAs) decorated with CNPQDs (CNPQD-STNA) generate 2.54 mA cm−2 photocurrent under AM1.5 G simulated sunlight. A champion hydrogen evolution rate of 22 µmol h−1 corresponds to a Faradaic efficiency of 93.2%. In conjunction with Ag nanoparticles (NPs), the CNPQD-STNA hybrid is also found to be an excellent plexcitonic photocatalyst for the visible light-driven transformation of 4-nitrobenzenethiol (4-NBT) to dimercaptoazobenzene (DMAB), producing reaction completion at a laser power of 1 mW (532 nm) while Ag NP/TNA and Ag NP/STNA photocatalysts cannot complete this transformation even at 10 mW laser power. The results point the way forward for photochemically robust, noble metal free, visible light harvesting photoacatalysts based on nanostructured heterojunctions of graphenic frameworks with TiO2.
Gamry’s eQCM 10M™ is a rapid, impedance-scanning electrochemical quartz crystal microbalance (EQCM) that adds a valuable tool in the analytical toolbox of anyone investigating interfacial processes.
A few Curious Aspects of ZnO Nanostructures - Prof.Joy MitraSTS FORUM 2016
This document summarizes research on designing defects in ZnO nanostructures. It discusses how ZnO naturally forms with n-type doping due to oxygen vacancies and zinc interstitials. The researcher investigates controlling the ratio of zinc interstitials to oxygen vacancies to tune the material's optical and electrical properties. Photoluminescence and conductive atomic force microscopy experiments on ZnO nanorods with varying defect concentrations show changes in emission spectra and localized photoresponse correlated with grain structure. The findings provide insight into defect engineering of ZnO for optoelectronic applications.
Plenary lecture given by Prof. Katsuhiko Ariga (WPI-MANA, NIMS and University of Tokyo, Japan) on September 12, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting.
In the focus of attention at the present time are the new rare earth‐cobalt‐based magnet alloys. This paper is primarily a qualitative review of the physical phenomena controlling their behavior and of the materials problems these magnets have posed. It also provides an outlook at possibilities for the development of still better or cheaper permanent magnets which current research on rare earth‐ transition metal alloys appears to provide. The origins of the magnetic moments and the crystal anisotropy of rare earth‐transition metal phases are discussed. Alternative concepts of the causes of coercivity in powders and sintered bodies are analyzed. Some basic aspects of the sintering of R‐Co compacts and the magnetic hardening of R–Co–Cu alloys in the massive state are reviewed. Specific problems related to particular alloys and applications of the magnets are pointed out. The conclusion is drawn that the new family of permanent magnets now emerging rivals in complexity both the Alnicos and the ferrites together. There are many development opportunities for the future, and we can expect that, eventually, magnets based on high‐anisotropy alloys containing rare earths will be offered in a variety of grades, covering a wide range of properties and prices, and that they will be produced by several drastically different methods.
Primary results or synthesis and characteristics of thin-film materials for PV converters. Work performed by 4-point-probe method, Hall effect, magnetron sputtering, electron microscopy.
Rare-earth nitrides such as GdN, SmN, and EuN are intrinsic ferromagnetic semiconductors that show promise for spintronic applications. Epitaxial thin films of these materials were grown with controlled stoichiometry and doping levels. GdN exhibits ferromagnetism below 70K with carrier-mediated exchange possibly enhancing its Curie temperature above 200K. SmN orders ferromagnetically below 27K despite having a net magnetic moment of zero, while EuN displays unexpected ferromagnetism below 25K likely due to Eu vacancies. Further studies of the electronic band structures and tunable magnetic and transport properties of these rare-earth nitrides could lead to new spintronic and
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.
The document discusses neutrino oscillations and the T2K experiment. It provides a brief history of neutrino discoveries and outlines the current neutrino oscillation model. The T2K experiment uses a neutrino beam produced at J-PARC that travels 295 km to the Super-Kamiokande detector. Recent T2K results and future prospects are discussed. The document raises several open questions in neutrino physics that ongoing experiments hope to address.
Xiaoxing Xi - Magnesium Diboride Thin Films for Superconducting RF Cavitiesthinfilmsworkshop
http://www.surfacetreatments.it/thinfilms
Magnesium Diboride Thin Films for superconducting RF cavities (Xiaoxing Xi - 40')
Speaker: Xiaoxing Xi - Temple University | Duration: 40 min.
Abstract
MgB2 has a Tc of 40 K, a low residual resistivity, and a high Hc . RF cavities coated with MgB2 films have the potential for a higher Q and gradient than Nb cavities with an operation temperature of 4.2 K or higher. At Temple University, we have started a project to study issues related to the application of MgB2 to RF cavities, and to coat single-cell RF cavities with MgB2 film for characterization by the collaborators in accelerator-compatible environment. The key technical thrust of this project is the deposition of high quality clean MgB2 films and coatings using a hybrid physical-chemical vapor deposition technique. I will review the progress to date in this project.
Resonant-tunneling-diode effect in Si-based double-barrier structure sputtere...IJRES Journal
This paper presents the resonant-tunneling-diode (RTD) effect in a SiO2/n-Si/SiO2/p-Si double-barrier structural thin films fabricated using radio frequency (RF) magnetron sputtering at room temperature (300 K). The implementation of a circuit prototype is first accomplished by modulating a Si-based RTD with a solar-cell bias voltage. The important electrical properties of the peak current density and peak-to-valley current ratio (PVCR) are 184 nA/cm2 and 1.67, respectively. The connection between the two RTDs in series is biased by a solar cell. The value of the switching transition time is 24.37 μs; oscillation occurs with an operating frequency of 41.6 KHz. In semiconductor applications, the developed RTD is characterized by stability, enduring environmentally elevated temperature and relative humidity.
The document summarizes the MiniCLEAN experiment, which aims to test a liquid argon detector design for dark matter searches. MiniCLEAN has completed construction and is undergoing commissioning. Key points include:
- MiniCLEAN will study light yield, position reconstruction, and background rejection techniques in liquid argon using a 500 kg detector.
- Construction is complete and cooling of the detector is underway. Analyses of LED calibration data and cryopit vacuum data are ongoing.
- Expected performance is a light yield of 6 photons/keV and background rate below 1 event/year in the fiducial volume. This would allow a WIMP sensitivity down to a cross-section of ~10^-10 pb.
The document summarizes the conception, construction, and testing of LIBO, a prototype linear accelerator module for a compact proton therapy facility. Key points:
- LIBO is a side-coupled linear accelerator structure operating at 3 GHz designed to boost the energy of a proton beam from 62 MeV to 200 MeV for cancer therapy applications.
- The design and construction of a prototype LIBO module is described, including the half-cell design, material selection, thermal stabilization, bridge couplers, and integration of permanent magnet quadrupoles.
- The prototype module was machined at CERN using numerical control and its components were brazed together under vacuum. RF measurements validated the electric field flatness was within 3
EMVT 12 september - Pavol Bauer - TU DelftDutch Power
This document discusses renewable energy and electrical power transmission technologies. It introduces offshore wind and wave energy technologies and the need for DC power grids to transmit renewable energy over long distances. Various electrical power conversion and transmission technologies are presented, including HVDC transmission using line-commutated converters and voltage source converters. Applications of HVDC systems include long-distance overhead lines, submarine cable connections, and interconnectors between asynchronous grids. Control and operation of HVDC converters in rectifier and inverter modes are also covered.
This document summarizes applications of the LDA+U and LDA+DMFT methods to strongly correlated materials. It discusses how LDA+U can describe Mott insulators, charge order, spin order, orbital order, and phase transitions. Applications included Fe3O4, KCuF3, Pr1-xCaxMnO3, and LaCoO3. It also introduces the dynamical mean-field theory (DMFT) method, which goes beyond LDA+U by including dynamical correlations. DMFT maps the lattice problem to an effective impurity problem, which can be solved using techniques like quantum Monte Carlo. The document outlines the DMFT self-consistency cycle and implementation of QMC as an impurity solver.
This chapter describes the fabrication of a zirconia nanoparticle-decorated reduced graphene oxide (ZrO2/rGO) nanocomposite for an electrochemical sensor to detect the anticancer drug regorafenib. Characterization using XRD, FT-IR, XPS, TEM and EDX confirmed the successful synthesis of ZrO2 nanoparticles on rGO. Electrochemical tests using cyclic voltammetry and differential pulse voltammetry showed the ZrO2/rGO modified electrode has excellent electrocatalytic activity for regorafenib oxidation, with a wide linear detection range of 11-343 nM and a low detection limit of 3.7 nM. The sensor also demonstrated good
Nucleon electromagnetic form factors at high-momentum transfer from Lattice QCDChristos Kallidonis
This document summarizes a presentation on calculating the nucleon electromagnetic form factors at high momentum transfer using lattice QCD. Key points:
1) Lattice QCD simulations were performed on two ensembles with different volumes but similar lattice spacing to calculate the nucleon form factors up to momentum transfers of 12 GeV^2.
2) Boosted nucleon states were used in the simulations to access higher momentum transfers while keeping nucleon energies low. Three-point correlation functions were calculated to extract the matrix elements.
3) Plateaus in the ratio of three-point to two-point functions were identified to obtain the form factors, and two-state fits were also used to account for excited state contributions.
Simple and direct synthesis of zinc vanadate ZnV2O5 nanocrystals for its elec...Arvind Singh Heer
Zinc Vanadate (ZnV2O5) Nanocrystals were prepared by two steps, ceramic route process. Optimization of the
ceramic route processing conditions enhances the Electrocatalytic and Antimicrobial performance of the prepared
nanoparticles. The thermally treated material was subjected to XRD, FTIR, UV-Visible spectroscopy, SEM and
EDS, which confirmed the formation of Zinc Vanadate (ZnV2O5) Nanocrystals. The electrochemical detection of
Anthracene by Zinc Vanadate nanoparticles was investigated by Cyclic Voltammetry. The result concludes that the
ZnV2O5 NPs have the higher activity for detection and oxidation of Anthracene. The as-synthesized ZnV2O5 NPs were
found to exhibit strong antimicrobial activity against both Escherichia coli (E.coli) gram-negative and
Staphylococcus aureus (S. aureus) gram-positive microorganisms implying their strong potential as the antimicrobial
agent.
This document describes a passively Q-switched Nd:YAG ceramic laser using a single wall carbon nanotube saturable absorber. The laser generated pulses with a maximum duration of 1.2 ms, repetition rate varying from 14 to 95 kHz, and maximum pulse energy of 4.5 mJ at a repetition rate of 31.8 kHz. The laser achieved a maximum output power of 376 mW and optical-to-optical conversion efficiency of 4.3% at a pump power of 8.68 W. Characterization of the Nd:YAG ceramic gain medium showed scattering and absorption losses similar to a crystal, with the ceramic laser demonstrating output power only 6.3% lower than an equivalent
The Muon g-2 experiment at Fermilab aims to precisely measure the anomalous magnetic moment of the muon to test predictions of the Standard Model. Current efforts involve shaping the magnetic field in the storage ring to reduce uncertainties. Laminating over 9,000 small iron foils around the ring poles has improved field consistency from 200 ppm to under 25 ppm azimuthally. Further reductions to below 0.5 ppm are expected to achieve the experiment's goal of limiting systematic uncertainties to 140 ppb.
This document discusses photocatalysis using semiconductors like TiO2. It describes the discovery of photocatalytic water splitting on a TiO2 electrode under UV light in 1972. The steps in photocatalysis are outlined as light absorption, generation of electron-hole pairs, migration/recombination of pairs, adsorption/desorption of reactants/products, and redox reactions. TiO2 is discussed as a common photocatalyst due to its stability, low cost, and oxidizing power. Different types of heterojunction photocatalysts - including Type I, II, III and p-n heterojunctions - are described in terms of their band structure and ability to separate electron-hole pairs. Surface
1) Researchers fabricated carbon nanotube field-effect transistors (CNTFETs) using dielectrophoresis to position carbon nanotubes and semiconductor materials like Sb2Te3 and Bi2Te2Se as the source and drain contacts. This approach selectively turned off metallic nanotubes to improve device performance.
2) The team implemented this novel fabrication process to create basic CNTFET circuits like an inverter. Electrical measurements showed the process enhanced characteristics like current on/off ratio compared to prior approaches.
3) Going forward, the method could enable wafer-scale integration of CNTFET-based nanoelectronic circuits using semiconductor contact materials.
Electronic structure of strongly correlated materials Part II V.AnisimovABDERRAHMANE REGGAD
This document summarizes applications of the LDA+U and LDA+DMFT methods to strongly correlated materials. It discusses how these methods can accurately model Mott insulators, charge order, spin order, orbital order, and other phenomena. Specific examples discussed include charge ordering in Fe3O4, orbital ordering in KCuF3 and LaMnO3, and the spin state of Co3+ in LaCoO3. It also outlines the theoretical foundations and computational schemes of the LDA+U and LDA+DMFT methods, such as how the quantum Monte Carlo method can be used to solve the effective impurity problem in LDA+DMFT.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Nano-confined fluids exhibit layering and ordering behavior not seen in bulk fluids. X-ray reflectivity studies of polystyrene films with thicknesses less than the polymer's radius of gyration showed layering with periodicity matching the film thickness. Atomic force microscopy found the surface energy of these nano-confined films was spatially varying. This leads to a new state for nano-confined fluids with low out-of-plane cohesion but tunable in-plane self-assembly of gold nanoparticles controlled by film thickness.
Recent neutrino oscillation results from T2KSon Cao
The document summarizes recent neutrino oscillation results from the T2K experiment. It begins with a brief history of neutrino discoveries and introduces the concept of neutrino oscillations. It then describes the T2K experiment, including the neutrino beam produced at J-PARC, the near detectors that characterize the beam, and the large far detector in Korea. The document presents the T2K collaboration's latest neutrino oscillation results and concludes by summarizing the current understanding of neutrino oscillations.
Este documento presenta los objetivos y resultados de una jornada científica sobre nanociencia e imanes permanentes con bajo contenido de tierras raras. Se describen los avances en el desarrollo de nuevos materiales magnéticos compuestos y en el estudio de redes ordenadas de microhilos magnéticos y sus interacciones con ondas electromagnéticas. También se muestran los resultados preliminares de un sistema de telemetría inalámbrica para el seguimiento de procedimientos vasculares basado en microhilos magnéticos.
The summary discusses the work of the Theoretical Chemistry Group at the Universidad Autónoma de Madrid (UAM). The group studies several topics including self-assembly of molecules on surfaces, graphene on metal surfaces, NO catalysis, fullerenes, and antimonene. Specific projects mentioned include studying the controlled self-assembly of TCNQ and TTF molecules on Cu(111) and Ag(111) surfaces, graphene intercalated with sulfur on Ru(0001) surfaces, and predicting the structures and stabilities of charged fullerene molecules.
1) Graphene has potential for spintronics applications due to its long spin diffusion length and ability to manipulate spin. Intercalating graphene with Pb on an Ir substrate induces a giant spin-orbit coupling that splits graphene's bands.
2) Depositing molecules like TCNQ on graphene can induce a Kondo effect and long-range magnetic order. TCNQ forms nearly flat, half-filled bands predicted to have a ferromagnetic ground state.
3) Pb intercalated graphene on Ir has properties resembling Landau levels without a magnetic field, with quantized resistance and possible applications in topological insulators.
This document summarizes research on improving the magnetic and electrical properties of type-II superconductors through nanostructured hybrids. It discusses using nanostructured defects like dots of materials like nickel to enhance pinning of vortices in the mixed state and reduce resistance. Arrays of magnetic dots on niobium films allow controlling the remanent magnetic state of the dots to realize three-state memory function and ratchet effects influencing voltage outputs. The compensation field and matching fields where resistance is minimized depend on sample design.
The document describes the current and future facilities for very high magnetic field scanning tunneling microscopy (VHT-STM) at the Laboratorio de Bajas Temperaturas at the Universidad Autónoma de Madrid. The current facilities include a dilution refrigerator STM that can reach temperatures as low as 7 mK combined with magnetic fields up to 9T. A new dilution refrigerator STM is under construction that will be capable of reaching 7 mK and applying a 17T magnetic field. Future facilities planned include a dilution refrigerator STM that can apply 22T at 7 mK and a hybrid magnet STM that can generate over 30T. The VHT-STM will allow scientists to visualize electronic correlations and perform Landau
This document discusses magnetic nanowires and microwires. It describes how cylindrical nanowires of various compositions, diameters, and geometries have been synthesized using electrochemical methods. These include uniform nanowires, nanowires with modulated diameters, and multisegmented nanowires. Characterization of individual nanowires reveals correlation between their crystal structure, composition, and magnetic properties. Modulated nanowires have been shown to exhibit tailored reversal behavior compared to uniform nanowires. Various techniques including Lorentz microscopy and photoemission electron microscopy with x-ray magnetic circular dichroism have provided insights into spin configurations in these artificial nanowire systems.
Signatures of wave erosion in Titan’s coastsSérgio Sacani
The shorelines of Titan’s hydrocarbon seas trace flooded erosional landforms such as river valleys; however, it isunclear whether coastal erosion has subsequently altered these shorelines. Spacecraft observations and theo-retical models suggest that wind may cause waves to form on Titan’s seas, potentially driving coastal erosion,but the observational evidence of waves is indirect, and the processes affecting shoreline evolution on Titanremain unknown. No widely accepted framework exists for using shoreline morphology to quantitatively dis-cern coastal erosion mechanisms, even on Earth, where the dominant mechanisms are known. We combinelandscape evolution models with measurements of shoreline shape on Earth to characterize how differentcoastal erosion mechanisms affect shoreline morphology. Applying this framework to Titan, we find that theshorelines of Titan’s seas are most consistent with flooded landscapes that subsequently have been eroded bywaves, rather than a uniform erosional process or no coastal erosion, particularly if wave growth saturates atfetch lengths of tens of kilometers.
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
BIRDS DIVERSITY OF SOOTEA BISWANATH ASSAM.ppt.pptxgoluk9330
Ahota Beel, nestled in Sootea Biswanath Assam , is celebrated for its extraordinary diversity of bird species. This wetland sanctuary supports a myriad of avian residents and migrants alike. Visitors can admire the elegant flights of migratory species such as the Northern Pintail and Eurasian Wigeon, alongside resident birds including the Asian Openbill and Pheasant-tailed Jacana. With its tranquil scenery and varied habitats, Ahota Beel offers a perfect haven for birdwatchers to appreciate and study the vibrant birdlife that thrives in this natural refuge.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
Compositions of iron-meteorite parent bodies constrainthe structure of the pr...Sérgio Sacani
Magmatic iron-meteorite parent bodies are the earliest planetesimals in the Solar System,and they preserve information about conditions and planet-forming processes in thesolar nebula. In this study, we include comprehensive elemental compositions andfractional-crystallization modeling for iron meteorites from the cores of five differenti-ated asteroids from the inner Solar System. Together with previous results of metalliccores from the outer Solar System, we conclude that asteroidal cores from the outerSolar System have smaller sizes, elevated siderophile-element abundances, and simplercrystallization processes than those from the inner Solar System. These differences arerelated to the formation locations of the parent asteroids because the solar protoplane-tary disk varied in redox conditions, elemental distributions, and dynamics at differentheliocentric distances. Using highly siderophile-element data from iron meteorites, wereconstruct the distribution of calcium-aluminum-rich inclusions (CAIs) across theprotoplanetary disk within the first million years of Solar-System history. CAIs, the firstsolids to condense in the Solar System, formed close to the Sun. They were, however,concentrated within the outer disk and depleted within the inner disk. Future modelsof the structure and evolution of the protoplanetary disk should account for this dis-tribution pattern of CAIs.
Farming systems analysis: what have we learnt?.pptx
2016.06.21 lbt uam NanoFrontMag
1. NUEVAS FRONTERAS DEL NANOMAGNETISMO FUNDAMENTAL Y APLICADO
4. Mejora de las propiedades magnéticas y eléctricas de los superconductores mediante la
fabricación de nanoestructuras hibridas
Objetivo 2: Control del campo magnético en nanoestructuras híbridas magnéticas/superconductoras
2. NUEVAS FRONTERAS DEL NANOMAGNETISMO FUNDAMENTAL Y APLICADO
4. Mejora de las propiedades magnéticas y eléctricas de los superconductores mediante la
fabricación de nanoestructuras hibridas
Objetivo 2: Control del campo magnético en nanoestructuras híbridas magnéticas/superconductoras
• ERC StG Pnicteyes, 1,7M€, PI Isabel Guillamón
• FIS2014-54498-R, 130k€, PI Hermann Suderow
• MDM-2014-0377, 160k€ Internal IFIMAC Project, Pis, Hermann Suderow and Alfredo Levy
• Nobu or Prof Nobuhiko Nishida, travel to Japan to see Toyota Museum …
3. • The size of the vortex core
• Pnictides or the iron age of superconductivity
Superconductivity
8. -2 -1 0 1 2
0.0
0.5
1.0
1.5
Normalizedconductance
Bias Voltage (mV)
-2 -1 0 1 2
0.0
0.5
1.0
1.5
Normalizedconductance
Bias voltage (mV)
0 mV 0.3 mV 0.5 mV
NbSe2
NbS2
Internal electronic structure of the vortex cores:
NbSe2 vs. NbS2
Superconducting density of states and vortex cores in NbS2
I. Guillamon, H. Suderow, S. Vieira and P. Rodiere
Phys Rev Lett, 101, 166407 (2008)
9. r
ns(r)
H(r)
r
E
|∆|
Vortex core shrinking with the magnetic field
Field dependence of the vortex core size
V.G. Kogan and N.V. Zhelezina,
Phys. Rev. B, 71, 134505 (2005).
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r
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E
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d/dr 1/H
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10. -Bi2Pd: Bi surface prepared by scotch method
140 nm
4.2 nm
1.7 nm
0.24 {1/A}
0 200
0
8
Z(A)
x(nm)
Pd
Bi
c
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b
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3.36 A
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11. -Bi2Pd: single gap superconductor
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0
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NormalizedConductance
Bias Voltage (mV)
0 1 2 3 4 5
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0.2
0.4
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(meV)
T(K)
-2 -1 0 1 2
0
1
2
3
4
5
6
7
8
3.0 K
2.0 K
1.0 K
0.5 K
NormalizedTunnelingConductance
Bias Voltage (mV)
0.1 K
4.0 K
3.7 K
3.5 K
4.4 K
5.0 K
4.6 K
4.2 K
12. -Bi2Pd: hexagonal vortex lattice
1
0
50 mT5 mT 100 mT 200 mT 250 mT
300 mT 350 mT 400 mT 450 mT 500 mT
59 nm 59 nm 59 nm 59 nm 59 nm
59 nm84 nm84 nm110 nm220 nm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
0.00 mm
147.66 mm
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147.66 mm
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1
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2
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4
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0.2T
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Bias Voltage (mV)
0.1T
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2H-NbS2
MgB2
2H-NbSe2
Single band
s-wave
-Bi2
Pd
mid
(r) B/B
c2
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70 nm
-Bi2Pd: Magnetic field dependence of the intervortex density of states
MgB2
Kohen et al Appl. Phys. Lett.
86, 212503 (2005).
14. Vortex core shrinking with the magnetic field
Field dependence of the vortex core size
V.G. Kogan and N.V. Zhelezina,
Phys. Rev. B, 71, 134505 (2005).
r
E
|∆|
d/dr 1/H
r
E
|∆|
d/dr 1/H
r
E
|∆|
d/dr 1/(Hc20
0.3 T
70 nm
Calculations by V.G. Kogan
IncreasingH
15. Vortex core shrinking with the magnetic field
Field dependence of the vortex core size
V.G. Kogan and N.V. Zhelezina,
Phys. Rev. B, 71, 134505 (2005).
r
E
|∆|
d/dr 1/H
r
E
|∆|
d/dr 1/H
r
E
|∆|
d/dr 1/(Hc20
IncreasingH
80nm