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Properties of the mixing layer height retrieved from ceilometer measurements in Slovakia and its relationship to the air pollutant concentrations

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Environmental Science and Pollution Research 2023年第54期30卷 115666-115682页

作者： Nguyen, Duy-Hieu Štefánik, Dušan Šedivá, Tereza Lin, Chitsan Ph.D. Program in Maritime Science and Technology College of Maritime National Kaohsiung University of Science and Technology Kaohsiung811213 Taiwan Slovak Hydrometeorological Institute Jeséniova 17 Bratislava833 15 Slovakia Faculty of Mathematics Physics and Informatics Comenius University in Bratislava Mlynská Dolina F1 Bratislava842 48 Slovakia Department of Marine Environmental Engineering National Kaohsiung University of Science and Technology Kaohsiung811213 Taiwan

Mixing layer height (MLH) is an important meteorological parameter for air quality since it significantly affects ground-level pollution in the atmosphere. This study examined the properties of the MLH on diurnal and seasonal timescales over a 3-year period (2020–2022) using high temporal resolution measurements from eight Vaisala CL31 ceilometers situated around Slovakia. Hourly averaged MLH data was retrieved from the BL-View software using merged method. The highest daily maxima for the MLH occurred mostly in summer and spring, while the lowest values occurred predominantly during winter and autumn. The average MLH daily maximum in summer was 2229 m, and just 859 m in winter. During summer, the spatial distribution of the MLH daily maxima was more uniform compared to winter, when the air masses within the individual valleys did not mix well. Correlations between ground-level pollutant concentrations and hourly mean/daily mean MLH were analyzed. The highest correlation, R≈0.6, was found for O3. For PM10, PM2.5, and NOx, the anticorrelations with MLH were found with maximum in winter (R ≈ − 0.3 for hourly data and R ≈ − 0.5 for daily mean data) but no relation in summer. Lastly, the ceilometer MLH was compared to the radiosonde retrieved MLH for various cloud covers. Our analysis is based on an extensive set of empirical data, which can improve the accuracy and effectiveness of meteorological and atmospheric chemistry models. The findings can support air pollution forecasting and warning systems, providing valuable insights for policymakers and researchers. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

关键词： Air quality

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SWING-BY DYNAMICS IN CONCEPT LEARNING AND COMPOSITIONAL GENERALIZATION

arXiv

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arXiv 2024年

作者： Yang, Yongyi Park, Core Francisco Lubana, Ekdeep Singh Okawa, Maya Hu, Wei Tanaka, Hidenori CBS-NTT Physics of Intelligence Program Harvard University CambridgeMA United States Physics & Informatics Laboratories NTT Research Inc. SunnyvaleCA United States Computer Science and Engineering University of Michigan Ann ArborMI United States Department of Physics Harvard University CambridgeMA United States

Prior work has shown that text-conditioned diffusion models can learn to identify and manipulate primitive concepts underlying a compositional data-generating process, enabling generalization to entirely novel, out-of-distribution compositions. Beyond performance evaluations, these studies develop a rich empirical phenomenology of learning dynamics, showing that models generalize sequentially, respecting the compositional hierarchy of the data-generating process. Moreover, concept-centric structures within the data significantly influence a model’s speed of learning the ability to manipulate a concept. In this paper, we aim to better characterize these empirical results from a theoretical standpoint. Specifically, we propose an abstraction of prior work’s compositional generalization problem by introducing a structured identity mapping (SIM) task, where a model is trained to learn the identity mapping on a Gaussian mixture with structurally organized centroids. We mathematically analyze the learning dynamics of neural networks trained on this SIM task and show that, despite its simplicity, SIM’s learning dynamics capture and help explain key empirical observations on compositional generalization with diffusion models identified in prior work. Our theory also offers several new insights—e.g., we find a novel mechanism for non-monotonic learning dynamics of test loss in early phases of training. We validate our new predictions by training a text-conditioned diffusion model, bridging our simplified framework and complex generative models. Overall, this work establishes the SIM task as a meaningful theoretical abstraction of concept learning dynamics in modern generative models. © 2024, CC BY.

关键词： Mapping

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Vibrational EELS for Solid-State Li-Ion Batteries: Mapping Li Distributions and Beyond

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Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 633-635页

作者： Gadre, Chaitanya A. Lee, Tom Qi, Ji Ong, Shyue Ping Pan, Xiaoqing Department of Physics and Astronomy University of California Irvine CA United States Department of Materials Science and Engineering University of California Irvine CA United States Materials Science and Engineering Program University of California San Diego La Jolla CA United States Department of NanoEngineering University of California San Diego La Jolla CA United States Irvine Materials Research Institute University of California Irvine CA United States

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Correlation versus dissipation in a non-Hermitian Anderson impurity model

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Physical Review B 2025年第12期111卷 125157-125157页

作者： Kazuki Yamamoto Masaya Nakagawa Norio Kawakami Department of Physics Tokyo Institute of Technology Meguro Tokyo 152-8551 Japan Department of Physics University of Tokyo Hongo Tokyo 113-0033 Japan Fundamental Quantum Science Program TRIP Headquarters RIKEN Wako 351-0198 Japan Department of Physics Ritsumeikan University Kusatsu Shiga 525-8577 Japan Department of Materials Engineering Science Osaka University Toyonaka Osaka 560-8531 Japan

We analyze the competition between strong correlations and dissipation in quantum impurity systems from the Kondo regime to the valence fluctuation regime by developing a slave-boson theory for a non-Hermitian Anderson impurity model with one-body loss. Notably, in the non-Hermitian Kondo regime, strong correlations qualitatively change the nature of dissipation through renormalization effects, where the effective one-body loss is suppressed and emergent many-body dissipation characterized by the complex-valued hybridization is generated. We unveil the mechanism of a dissipative quantum phase transition of the Kondo state on the basis of this renormalization effect, which counterintuitively enhances the lifetime of the impurity against loss. We also find a crossover from the non-Hermitian Kondo regime to the valence fluctuation regime dominated by one-body dissipation. Our results can be tested in a wide variety of setups such as quantum dots coupled to electronic leads and quantum point contacts in ultracold Fermi gases.

关键词： Bosons

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Percolation Nature of Threshold Switching: an Experimental Verification

Percolation Nature of Threshold Switching: an Experimental V...

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IEEE Conference on Nanotechnology

作者： Suman Devkota Brendan M Kuzior Victor G. Karpov Daniel G. Georgiev Frank Li Vamsi Borra Electrical and Computer Engineering program Youngstown State University Youngstown OH OH USA Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science respectively University of Toledo Toledo OH USA

This paper details a process used to create an interconnect in a conducting systems, such as amorphous or polycrystalline semiconductors. An experimental verification on the plasticity that supports the percolation conduction mechanism is provided. The plasticity observed in the sample could be harnessed in the development of new electronic devices that require flexibility and adaptability, such as wearable electronics and bendable screens. Overall, TEM characterization, in combination with SAED analysis, revealed a highly oriented crystalline structure in the sample. In addition, the results of this study have implications for the design of new memory devices that are based on a percolation conduction mechanism, which could potentially lead to the development of more efficient and reliable non-volatile storage technologies.

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2mm Continuous DOI Positioning in Arrays of Side-Coupled Crystals for a Highly Compact 100 ps FWHM CTR TOF-PET Detector Design

2mm Continuous DOI Positioning in Arrays of Side-Coupled Cry...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： S. Pourashraf J. W. Cates D. Innes M.N. Ullah C. S. Levin Radiology Department Stanford University Stanford California United States of America Lawrence Berkeley National Laboratory Applied Nuclear Physics Program Berkeley California United States of America Bioengineering Physics and Electrical Engineering Stanford University Stanford California United States of America

ISBN: (数字)9798350388152

ISBN: (纸本)9798350388169

To achieve more accurate depth-of-interaction (DOI) response and 3D positioning of photoelectric or scattered events in our highly compact 100 ps CTR TOF-PET detector design, we have replaced a previously CPLD-based 3DPS approach with a 3D position sensitive charge-division scalable readout which better preserves our ∼100 ps FWHM CTR results. To validate the performance and compatibility of the readout with our mixed-signal TOF-PET design, we used $2 \times 4$ arrays of $3 \times 3 \times 10 \mathrm{~mm}^{3}$ LGSO crystals side-coupled to $4 \times 6$ arrays of $3 \times 3 \mathrm{~mm}^{2}$ SiPMs. By embedding this 3DPS readout in our scaled-up TOF-PET system, we resolved 3D interaction positions along the crystal array with an average 1.6 mm FWHM DOI resolution while easily preserving our 100 ps CTR and also saving the components, footprint, and subsequently the cost, power dissipation by 32% and at least 40% compared to our previous 3DPS CPLD-based and the common 3D Anger-based readouts, respectively.

关键词： Microwave integrated circuits Three-dimensional displays Costs Accuracy Semiconductor detectors Crystals Power dissipation

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Spin scattering and Hall effects in monolayer Fe3GeTe2

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Physical Review B 2023年第13期108卷 134425-134425页

作者： Luyan Yu Jie-Xiang Yu Jiadong Zang Roger K. Lake Houlong Zhuang Gen Yin Department of Physics University of Texas at Austin Austin Texas 78712 USA Department of Physics University of Florida Gainesville Florida 32611 USA Department of Physics and Materials Science Program University of New Hampshire Durham New Hampshire 03824 USA Laboratory for Terahertz and Terascale Electronics (LATTE) Department of Electrical and Computer Engineering University of California at Riverside Riverside California 92521 USA Mechanical and Aerospace Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Georgetown University Washington DC 20057 USA

We theoretically show that the carrier transport in a monolayer Fe3GeTe2 experiences a transition between anomalous and spin Hall effects when the spin polarization of disorders switches between out-of-plane and in-plane. These Hall effects are allowed when the magnetization is polarized in-plane, breaking the C3 rotation symmetry. The transition originates from the selection rule of spin scattering, the strong spin-orbit coupling, and the van Hove singularities near the Fermi surface. The scattering selection rule tolerates the sign change of the disorder spin, which provides a convenient method to detect the switching of antiferromagnetic insulators regardless of the interfacial roughness in a heterostructure. This provides a convenient platform for the study of 2D spintronics through various van der Waals heterostructures.

关键词： Magnetotransport Spin Hall effect 2-dimensional systems Density functional calculations

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Biomimetic Synthesis of the Plasmodium falciparum Malaria Pigment and engineering of its Physical Attributes via pH Control

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Biomedical Materials and Devices 2025年第1期3卷 638-645页

作者： Azad, Saeed Al Shboul, Ahmad Lacroix, Christian Izquierdo, Ricardo Ménard, David Olivier, Martin Guerrero, Carlos Villalba Ung, Bora Department of Electrical Engineering École de technologie supérieure Montreal H3C 1K3 Canada Department of Electrical Engineering LACIME Montreal H3C 1K3 Canada Department of Engineering Physics Regroupement Québécois sur les Matériaux de Pointe (RQMP) Polytechnique Montréal Montréal H3T 1J4 QC Canada The Research Institute of the McGill University Health Centre Program in Infectious Diseases and Immunology in Global Health Departments of Medicine Microbiology and Immunology McGill University Montreal Canada

Although preventable and curable if diagnosed early, malaria still represents a life-threatening illness affecting over 200 million people every year with a significant mortality rate (2.4%). Research for the development of convenient and rapid diagnostic methods have recently shown promise in using the magneto-optical properties of the hemozoin compound, an iron-rich by-product excreted by malaria parasites, most notably the Plasmodium falciparum species, during ingestion of hemoglobin in the host’s blood. However, much research is still required in order to fully understand and exploit the properties of the hemozoin toward early-onset diagnosis of the illness. In this regard, access to an innocuous and controllable synthetic form of hemozoin (SHz) would be an invaluable tool to promote research in this area. The present work describes a straightforward aqueous acid-catalyzed technique for producing SHz with controlled dimensions and magnetic response that result in SHz samples with properties similar to natural hemozoin caused by Plasmodium falciparum. In particular, the results indicate that SHz with the closest resemblance to the natural hemozoin exhibits a paramagnetic response with magnetic susceptibility of 1.4E−5 and a refractive index of 1.7035 along the preferred crystallographic growth direction at 635 nm wavelength. The findings reported in this study provide new insights relevant to magneto-optic biomedical sensing and biochemical synthesis methods. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.

关键词： Hemozoin Magnetic and optical properties Malaria pigment

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Camera-based Motion Correction for PET/MR Brain Imaging

Camera-based Motion Correction for PET/MR Brain Imaging

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2022 IEEE Nuclear Science Symposium, Medical Imaging Conference, and Room Temperature Semiconductor Detector Conference, IEEE NSS MIC RTSD 2022

作者： Fisher, Jonathan Groll, Andrew Kim, Chris C. Innes, Derek Levin, Craig S. Stanford University Department of Electrical Engineering CA United States Molecular Imaging Program Stanford University Department of Radiology CA United States Stanford University Department of Computer Science CA United States Stanford University Physics Electrical Engineering and Bioengineering Department of Radiology CA United States

ISBN: (纸本)9781665488723

In this work, we evaluated the performance of a camera-based rigid body motion correction solution in PET studies. We compared the image quality obtained by reconstructing a static phantom scan to those obtained by reconstructing a moving phantom scan with and without applying motion correction. Our suggested solution uses a camera to track a 3D marker attached to the object to be imaged (in this work, a resolution phantom). This data was incorporated in the multiple acquisition frames (MAF) image reconstruction algorithm to compensate for motion. While we got multiple spatially shifted replicas of the resolution phantom in the motion study's reconstructed image when motion correction was not applied, the motion-corrected image was comparable to the static image, with some degradation in spatial resolution (3.2-4.2 vs. 2.8-3.2 mm) and lower peak to valley ratio (indicating lower contrast to noise ratio). The context of the results presented is in PET/MR imaging, but in principle, this motion compensation method could be used in any type of medical imaging modality. © 2022 IEEE.

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Opto2P-FCM: A MEMS Based Miniature Two-Photon Microscope with Patterned Optogenetic Stimulation

Opto2P-FCM: A MEMS Based Miniature Two-Photon Microscope wit...

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Microscopy Histopathology and Analytics, Microscopy 2024 - Part of Optica Biophotonics Congress: Biomedical Optics

作者： Futia, Gregory L. Zohrabi, Mo McCullough, Connor Teel, Alec de Souza, Fabio Simoes Oroke, Ryan Bright, Victor M. Restrepo, Diego Gopinath, Juliet T. Gibson, Emily A. Department of Bioengineering University of Colorado Anschutz Medical Campus AuroraCO80045 United States Department of Cell and Developmental Biology University of Colorado Anschutz Medical Campus AuroraCO80045 United States Department of Electrical Computer and Energy Engineering University of Colorado BoulderCO80309 United States Department of Mechanical Engineering University of Colorado BoulderCO80309 United States Department of Physics University of Colorado BoulderCO80309 United States Materials Science and Engineering Program University of Colorado BoulderCO80309 United States

Miniaturized microscopes for monitoring neural activity are an indispensable tool for neuroscience research. We present a novel MEMS based miniature microscope with patterned optogenetic stimulation capabilities enabl... 详细信息

ISBN: (纸本)9781957171340

关键词： Microscopes

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