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arXiv 2017年

作者： Wei, Guohua Lenferink, Erik J. Czaplewski, David A. Stern, Nathaniel P. Applied Physics Program Northwestern University 2145 Sheridan Road EvanstonIL60208 United States Department of Physics and Astronomy Northwestern University 2145 Sheridan Road EvanstonIL60208 United States Center for Nanoscale Materials Argonne National Laboratory 9700 S Cass Avenue ArgonneIL60439 United States

Single layers of transition metal dichalcogenides such as MoS2 are direct bandgap semiconductors with optical and electronic properties distinct from multilayers due to strong vertical confinement. Despite the fundamental monolayer limit of thickness, the electronic structure of isolated layers can be further tailored with lateral degrees of freedom in nanostructures such as quantum dots or nanoribbons. Although one-dimensionally confined monolayer semiconductors are predicted to have interesting size-and edge-dependent properties useful for spintronics applications, experiments on the opto-electronic features of monolayer transition metal dichalcogenide nanoribbons is limited. We use nanolithography to create monolayer MoS2 nanoribbons with lateral sizes down to 20 nm. The Raman spectra show polarization anisotropy and size-dependent intensity. The nanoribbons prepared with this technique show reduced susceptibility to edge defects and emit photoluminescence with size-dependent energy that can be understood from a phenomenological model. Fabrication of monolayer nanoribbons with strong exciton emission can facilitate exploration of low-dimensional opto-electronic devices with controllable properties. Copyright © 2017, The Authors. All rights reserved.

关键词： Monolayers

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Reduced modeling of porous media convection in a minimal flow unit at large Rayleigh number

arXiv

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arXiv 2018年

作者： Wen, Baole Chini, Gregory P. Department of Geological Sciences Jackson School of Geosciences University of Texas at Austin AustinTX78712 United States Institute of Computational Engineering and Sciences University of Texas at Austin AustinTX78712 United States Program in Integrated Applied Mathematics University of New Hampshire W113 Kingsbury Hall 33 Academic Way DurhamNH03824 United States Center for Fluid Physics University of New Hampshire DurhamNH03824 United States Department of Mechanical Engineering University of New Hampshire DurhamNH03824 United States

Direct numerical simulations (DNS) indicate that at large values of the Rayleigh number (Ra) convection in porous media self-organizes into narrowly-spaced columnar flows, with more complex spatiotemporal features being confined to boundary layers near the top and bottom walls. In this investigation of high-Ra porous media convection in a minimal flow unit, two reduced modeling strategies are proposed that exploit these specific flow characteristics. Both approaches utilize the idea of decomposition since the flow exhibits different dynamics in different regions of the domain: small-scale cellular motions generally are localized within the thermal and vorticity boundary layers near the upper and lower walls, while in the interior, the flow exhibits persistent large-scale structures and only a few low (horizontal) wavenumber Fourier modes are active. Accordingly, in the first strategy, the domain is decomposed into two near-wall regions and one interior region. Our results confirm that suppressing the interior high-wavenumber modes has negligible impact on the essential structural features and transport properties of the flow. In the second strategy, a hybrid reduced model is constructed by using Galerkin projection onto a fully a priori eigenbasis drawn from energy stability and upper bound theory, thereby extending the model reduction strategy developed by Chini et al. (Physica D, vol. 240, 2011, pp. 241-248) to large Ra. The results indicate that the near-wall upper-bound eigenmodes can economically represent the small-scale rolls within the exquisitely-thin thermal boundary layers. Relative to DNS, the hybrid algorithm enables over an order-of-magnitude increase in computational efficiency with only a modest loss of accuracy. Copyright © 2018, The Authors. All rights reserved.

关键词： Porous materials

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Composition and structural studies of glass fertilizer

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Journal of physics: Conference Series 2018年第1期1120卷

作者： N Kiwsakunkran N Chanthima J Kaewkhao N. Sangwaranateec Physics Program Faculty of Science and Technology Nakhon Pathom Rajabhat University Nakhon Pathom 73000 Thailand Center of Excellence in Glass Technology and Materials science (CEGM) Nakhon Pathom Rajabhat University Nakhon Pathom 73000 Thailand Applied Physics Faculty of Science and Technology Suan Sunandha Rajabhat University Bangkok 10300 Thailand

Glass fertilizers are new type of advanced and controlled released fertilizer and made of glass matrixes with macro elements most useful for plants and also incorporated with microelements which are important to the growth and development of corps or plants. This study the glasses sample was prepared, which may be used as slow release fertilizer for different type of plant. All of samples were analyzed by using X-ray fluorescence (XRF), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR). The results of the experiments reported here demonstrate that is possible to adjust the release of phosphate from the fertilizer to phosphate demand of the plant.

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INTRODUCTION

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Bulletin of the American Meteorological Society 2024年第8期105卷 S1-S11页

作者： Boyer, T. Blunden, J. Dunn, R.J.H. NOAA/NESDIS National Centers for Environmental Information Silver Spring Maryland NOAA/NESDIS National Centers for Environmental Information Asheville North Carolina Met Office Hadley Centre Exeter United Kingdom European Centre for Medium-Range Weather Forecasts Reading United Kingdom University of Maryland College Park Maryland Scripps Institution of Oceanography University of California San Diego La Jolla California NOAA/NWS National Centers for Environmental Prediction Climate Prediction Center College Park Maryland Brandenburg University of Technology (BTU) Cottbus-Senftenberg Germany Servicio Meteorológico Nacional Buenos Aires Argentina NOAA/OAR Physical Sciences Laboratory Boulder Colorado European Centre for Medium-Range Weather Forecasts Bonn Germany Center for Geophysical Research and School of Physics University of Costa Rica San José Costa Rica Department of Meteorology and National Centre for Earth Observation University of Reading Reading United Kingdom Centro Nacional de Monitoramento e Alertas de Desastres Naturais CEMADEN São Paulo Brazil Université Grenoble Alpes Institut des Géosciences de l’Environnement IRD CNRS Grenoble INP Grenoble France Hampton University Hampton Virginia Seychelles Meteorological Authority Mahe Seychelles Section for Glaciers Ice and Snow Norwegian Water Resources and Energy Directorate Oslo Norway National Research Institute for Agriculture Food and Environment (INRAE) CARRTEL Université Savoie Mont Blanc Thonon les Bains France Graduate School of Agriculture Osaka Metropolitan University Sakai Japan Science Faculty Universidad Nacional de Colombia Bogotá Colombia University of Bremen Bremen Germany NOAA Global Monitoring Laboratory Boulder Colorado Servicio Nacional de Meteorología e Hidrología del Perú Lima Perú Centro de Investigaciones sobre Desertificación – Spanish National Research Council (CSIC-UV-GVA) Valencia Spain Hydro-Climate Extremes Lab (H-CEL) Ghent University Ghent Belgium Department o

In 2023, La Niña conditions that generally prevailed in the eastern Pacific Ocean from mid-2020 into early 2023 gave way to a strong El Niño by October. Atmospheric concentrations of Earth’s major greenhouse gases—carbon dioxide, methane, and nitrous oxide—all increased to record-high levels. The annual global average carbon dioxide concentration in the atmosphere rose to 419.3±0.1 ppm, which is 50% greater than the pre-industrial level. The growth from 2022 to 2023 was 2.8 ppm, the fourth highest in the record since the 1960s. The combined short-term effects of El Niño and the long-term effects of increasing levels of heat-trapping gases in the atmosphere contributed to new records for many essential climate variables reported here. The annual global temperature across land and oceans was the highest in records dating as far back as 1850, with the last seven months (June–December) having each been record warm. Over land, the globally averaged temperature was also record high. Dozens of countries reported record or near-record warmth for the year, including China and continental Europe as a whole (warmest on record), India and Russia (second warmest), and Canada (third warmest). Intense and widespread heatwaves were reported around the world. In Vietnam, an all-time national maximum temperature record of 44.2°C was observed at Tuong Duong on 7 May, surpassing the previous record of 43.4°C at Huong Khe on 20 April 2019. In Brazil, the air temperature reached 44.8°C in Araçuaí in Minas Gerais on 20 November, potentially a new national record and 12.8°C above normal. The effect of rising temperatures was apparent in the cryosphere, where snow cover extent by June 2023 was the smallest in the 56-year record for North America and seventh smallest for the Northern Hemisphere overall. Heatwaves contributed to the greatest average mass balance loss for Alpine glaciers around the world since the start of the record in 1970. Due to rapid volume loss beginning in 2021, St. A

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Strain Distribution in Circular Disk of PMMA by Using Reflection Polariscope

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Journal of physics: Conference Series 2018年第1期1144卷

作者： Y Manjit A Limpichaipanit A Ngamjarurojana Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Faculty of Science at Si Racha Kasetsart University Si Racha Campus Chon Buri 20230 Thailand PhD's Degree Program in Applied Physics Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand

The experiment was conducted to study strain distribution in circular disk of PMMA by photoelasticity in reflection polariscope. The strain in circular disk was induced by two point load created by hydraulic system (535.37-994.63 N) with the step increase of 153.21 N. We added the Babinet compensater in basic reflection polariscope to observe the fractional isochromatic fringe order in the first quadrant of disk and we calculated strain by using stressstrain optic laws. The result showed the relation between absolute of different strain in first quadrant of circular disk and the relation of force with absolute of different strain. It was found that maximum different strain produced at contact area of disk decreased along horizontal and vertical direction. The relation of force with different strain was linear.

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Honeycomb Networks of Metal Oxides from Self-Assembling PS-PMMA Block Copolymers

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Microscopy and Microanalysis 2017年第S1期23卷 1654-1655页

作者： Frank Barrows Paul Nealey Tamar Segal-Peretz Liliana Stan Jeffrey Elam Anil Mane Ellie Porath Charudatta Phatak Amanda Petford-Long Applied Physics Program Northwestern University Evanston IL USA Material Science Division Argonne National Laboratory Argonne IL USA Technion- Israel Institute of Technology Haifa Israel Center for Nanoscale Materials Argonne National Laboratory Argonne IL USA Energy Science Division Argonne National Laboratory Argonne IL USA Physics Department University of Chicago Chicago IL USA

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Wear characterization of nano-hydroxyapatite with addition of titanium (HA-Ti)

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IOP Conference Series: Materials Science and Engineering 2018年第1期348卷

作者： R. Rosmamuhamadani A.Z.O. Arawi M.K. Talari M.M. Mahat N.N. Bonnia Sabrina M. Yahaya S. Sulaiman M.I.S. Ismail Materials Technology Program School of Physics & Material Studies Faculty of Applied Sciences Universiti Teknologi MARA Selangor 40450 Shah Alam Selangor Malaysia Mechanical and Manufacturing Department Faculty of Engineering Universiti Putra Malaysia 43400 Serdang Selangor Malaysia

Hydroxyapatite (Ca10 (PO4)6(OH)2, HA), is an attractive material of an inorganic compound whose chemical composition and crystallographic structures are similar to the composition of the bone. A natural source such as egg shells is composed of 94 wt. % of calcium carbonate (CaCO3), which can be calcined as calcium oxide (CaO) by the calcinations process. The efficient temperature to produce CaO is 900 °C for 2 hours. The synthesis of nano-HA was done by the mixing the diammonium phosphate (DAP) and calcium hydroxide (Ca(OH)2) and subjected into a microwave for 30 minutes at 1100 W irradiation power. Ball milling process was used for 30 minutes to mix the nano-HA with different compositions of titanium. These were pressed to form pallets by hand hydraulic pump (force=2300 psi). The pallets then were sintered at 1200 °C with the heating rate of 3 °C/min for 2 hours. The pallets were tested by several mechanical testing including hardness, compression strength and wear. From the results, HA-25wt. %Ti composite gave the highest hardness, compression and coefficient of friction for wear test values which were 89.6 Hv, 82.5MPa and 0.76μ respectively. It showed that by adding Ti to nano-HA, the mechanical properties of nano-HA could be enhanced. The microstructure analyses by optical micrograph showed that nano-HA-Ti particles displayed shape likes needle morphology. The particles showed the high tendency to form the agglomerations.

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Luminescence study and Judd-Ofelt analysis of CaO-BaO-P 2 O 5 glasses doped with Nd 3+ ions

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Materials Today: Proceedings 2017年第5期4卷 6091-6098页

作者： N. Chanthima J. Kaewkhao Y. Tariwong N. Sangwaranatee N.W. Sangwaranatee Physics Program Faculty of Science and Technology Nakhon Pathom Rajabhat University Nakhon Pathom 73000 Thailand Center of Excellence in Glass Technology and Materials Science (CEGM) Nakhon Pathom Rajabhat University Nakhon Pathom 73000 Thailand Applied Physics Faculty of Science and Technology Suan Sunandha Rajabhat University Bangkok 10300 Thailand Informatics Mathematics Faculty of Science and Technology Suan Sunandha Rajabhat University Bangkok 10300 Thailand

Neodymium (Nd 3+ ) doped calcium barium phosphate glasses have been studied in different concentration of Nd 3+ ions. The absorption and luminescence spectra, the Judd–Ofelt (JO) intensity parameters Ω 2,4,6 and other radiative properties, which is radiative transition probabilities ( A R ), stimulated emission cross-sections (σ(λ p ) and branching ratios ( β R ) were calculated. These glass samples have shown strong absorption bands in the visible (VIS) and near-infrared (NIR) region. The emission spectra of glass samples have exhibited three emission transitions, which are assigned to 4 F 3/2 → 4 I 9/2 , 4 F 3/2 → 4 I 11/2 and 4 F 3/2 → 4 I 13/2 transitions, respectively. Also, the results obtained were compared with reports on similar glasses.

关键词： Judd-Ofelt analysis Luminescence Neodymium Phosphate glasses

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EP21.01: Confocal microtomography (micro-CT) analysis and three-dimensional (3D) reconstruction of pathological conditions affecting the human fallopian tube (FT)

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Ultrasound in Obstetrics & Gynecology 2018年第S1期52卷 272-273页

作者： P.T. Castro O.L. Aranda A.P. Matos E. Marchiori H.D. Alves R.T. Lopes A.S. Machado H. Werner E. Araujo Junior Womens' Health FTE Souza Marques Rio de Janeiro Brazil Radiology Federal University of Rio de Janeiro Rio de Janeiro Brazil Obstetrics and Gynecology Vassouras University Vassouras Rio de Janeiro Brazil CDPI Rio de Janeiro Brazil Fetal Medicine Alta Excelência Diagnóstica Rio de Janeiro Brazil Applied Physics and Thermodynamics Department Universidade Do Estado do Rio de Janeiro Rio de Janeiro Brazil Nuclear Engineering Program (PEN/COPPE) Federal University of Rio de Janeiro Rio de Janeiro Brazil Obstetrics Federal University of São Paulo São Paulo Brazil

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Author Correction: Emission budgets and pathways consistent with limiting warming to 1.5 °C

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Nature Geoscience 2018年第6期11卷 454-455页

作者： Richard J. Millar Jan S. Fuglestvedt Pierre Friedlingstein Joeri Rogelj Michael J. Grubb H. Damon Matthews Ragnhild B. Skeie Piers M. Forster David J. Frame Myles R. Allen College of Engineering Mathematical and Physical Sciences University of Exeter Exeter UK Environmental Change Institute University of Oxford Oxford UK Center for International Climate and Environmental Research—Oslo (CICERO) Blindern Norway Energy Program International Institute for Applied Systems Analysis (IIASA) Laxenburg Austria Institute for Atmospheric and Climate Science ETH Zurich Zurich Switzerland Institute for Sustainable Resources University College London London UK Concordia University Montreal Canada School of Earth and Environment University of Leeds Leeds UK New Zealand Climate Change Research Institute Victoria University of Wellington Wellington New Zealand Department of Physics University of Oxford Oxford UK

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