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arXiv 2023年

作者： Camarasa-Gómez, María Ramasubramaniam, Ashwin Neaton, Jeffrey B. Kronik, Leeor Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Materials Science and Engineering Graduate Program University of Massachusetts Amherst AmherstMA01003 United States Department of Physics University of California BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute at Berkeley University of California BerkeleyCA94720 United States

The accurate description of electronic properties and optical absorption spectra is a long-standing challenge for density functional theory. Recently, the introduction of screened range-separated hybrid (SRSH) functionals for solid-state materials has allowed for the calculation of fundamental band gaps and optical absorption spectra that are in very good agreement with many-body perturbation theory. However, since solid-state SRSH functionals are typically tuned to reproduce the properties of bulk phases, their transferability to low-dimensional structures, which experience substantially different screening than in the bulk, remains an open question. In this work, we explore the transferability of SRSH functionals to several prototypical van der Waals materials, including transition-metal sulfides and selenides, indium selenide, black phosphorus, and hexagonal boron nitride. Considering the bulk and a monolayer of these materials as limiting cases, we show that the parameters of the SRSH functional can be determined systematically, using only the band-edge quasiparticle energies of these extremal structural phases as fitting targets. The resulting SRSH functionals can describe both electronic bandstructures and optical absorption spectra with accuracy comparable to more demanding ab initio many-body perturbation theory (GW and Bethe-Salpeter equation) approaches. Selected examples also demonstrate that the SRSH parameters, obtained from the bulk and monolayer reference structures, display good accuracy for bandstructures and optical spectra of bilayers, indicating a degree of transferability that is independent of the fitting procedure. Copyright © 2023, The Authors. All rights reserved.

关键词： Transition metals

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The Impact of Greening Strategies on Temperature Reduction at Bus Stop Utilizing computational Fluid Dynamics (Cfd) Analysis

SSRN

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SSRN 2024年

作者： Kim, Na Youn Kim, Eun Sub Yun, Seokhwan Lee, Dong Kun Department of Landscape Architecture and Rural System Engineering Seoul National University Seoul08826 Korea Republic of Interdisciplinary Program in Landscape Architecture Seoul National University Seoul08826 Korea Republic of Integrated Major in Smart City Global Convergence Program Seoul National University Seoul08826 Korea Republic of Specialized Graduate School of Intelligent Eco-Science 4 Dept. of Landscape Architecture Seoul National University Seoul08826 Korea Republic of

This study analyzed the effectiveness of a vegetation strategy for mitigating heat within a bus stop shelter by implementing vegetation wind permeability and transpiration cooling processes using a computational fluid dynamics (CFD) simulation. In scenario 1, a pot-type vertical greening system (VGS) without wind permeability had no significant effect on temperature reduction in the bus stop shelter. In contrast, scenario 2, with a mesh VGS allowing wind permeability, resulted in an average temperature reduction of 0.16°C within the interior area of the bus stop shelter, accompanied by shelter improved ventilation. Scenario 3, which entailed the removal of the shelter and the planting of trees, resulted in the least reduction in wind speed and an average temperature reduction of 0.14°C in the bus waiting area. Scenario 2 demonstrated the most effective temperature reduction for interior and surrounding area of the bus stop. Considering the normal effective temperature (NET), Scenario 3 provided the lowest sensation temperature. This indicates that the improved ventilation in Scenario 3 had a substantial impact on NET. Considering the effects of the vegetation strategies proposed in this study, it is essential to select suitable strategies for heat mitigation in bus-stop shelters based on regional and spatial considerations. © 2024, The Authors. All rights reserved.

关键词： computational fluid dynamics

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computational design of anisotropic stealthy hyperuniform composites with engineered directional scattering properties

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Physical Review E 2023年第4期108卷 045306-045306页

作者： Wenlong Shi David Keeney Duyu Chen Yang Jiao Salvatore Torquato Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Materials Research Laboratory University of California Santa Barbara California 93106 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Disordered hyperuniform materials are an emerging class of exotic amorphous states of matter that endow them with singular physical properties, including large isotropic photonic band gaps, superior resistance to fracture, and nearly optimal electrical and thermal transport properties, to name but a few. Here we generalize the Fourier-space-based numerical construction procedure for designing and generating digital realizations of isotropic disordered hyperuniform two-phase heterogeneous materials (i.e., composites) developed by Chen and Torquato [Acta Mater. 142, 152 (2018)] to anisotropic microstructures with targeted spectral densities. Our generalized construction procedure explicitly incorporates the vector-dependent spectral density function χ̃V(k) of arbitrary form that is realizable. We demonstrate the utility of the procedure by generating a wide spectrum of anisotropic stealthy hyperuniform microstructures with χ̃V(k)=0 for k∈Ω, i.e., complete suppression of scattering in an “exclusion” region Ω around the origin in Fourier space. We show how different exclusion-region shapes with various discrete symmetries, including circular-disk, elliptical-disk, square, rectangular, butterfly-shaped, and lemniscate-shaped regions of varying size, affect the resulting statistically anisotropic microstructures as a function of the phase volume fraction. The latter two cases of Ω lead to directionally hyperuniform composites, which are stealthy hyperuniform only along certain directions and are nonhyperuniform along others. We find that while the circular-disk exclusion regions give rise to isotropic hyperuniform composite microstructures, the directional hyperuniform behaviors imposed by the shape asymmetry (or anisotropy) of certain exclusion regions give rise to distinct anisotropic structures and degree of uniformity in the distribution of the phases on intermediate and large length scales along different directions. Moreover, while the anisotropic exclusion regions

关键词： Amorphous materials Complex materials Simulated annealing

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Million-Q Free Space Meta-Optical Resonator at Visible Wavelengths

arXiv

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arXiv 2024年

作者： Fang, Jie Chen, Rui Sharp, David Renzi, Enrico M. Manna, Arnab Kala, Abhinav Mann, Sander A. Yao, Kan Munley, Christopher Rarick, Hannah Tang, Andrew Pumulo, Sinabu Zheng, Yuebing Menon, Vinod M. Alù, Andrea Majumdar, Arka Department of Electrical and Computer Engineering University of Washington SeattleWA98195 United States Department of Physics University of Washington SeattleWA98195 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10016 United States Walker Department of Mechanical Engineering Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States Department of Physics City College of New York New YorkNY10031 United States

High-quality (Q)-factor optical resonators with extreme temporal coherence are of both technological and fundamental importance in optical metrology1,2, continuous-wave lasing3-5, and semiconductor quantum optics6-8. Despite extensive efforts in designing high-Q resonators across different spectral regimes, the experimental realization of very large Q-factors at visible wavelengths remains challenging due to the small feature size that is sensitive to fabrication imperfections9-12, and thus is typically implemented in integrated photonics1-4,9,10. In the pursuit of free-space optics with the benefits of large space-bandwidth product and massive parallel operations13,14, here we design and fabricate a visible-wavelength etch-free metasurface with minimized fabrication defects and experimentally demonstrate a million-scale ultrahigh-Q resonance. A new laser-scanning momentum-space-resolved spectroscopy technique with extremely high spectral and angular resolution is developed to characterize the record-high Qfactor as well as the dispersion of the million-Q resonance in free space. By integrating monolayer WSe2 into our ultrahigh-Q meta-resonator, we further demonstrate laser-like highly unidirectional and narrow-linewidth exciton emission, albeit without any operating power density threshold. Under continuous-wave laser pumping, we observe pump-power-dependent linewidth narrowing at room temperature, indicating the potential of our meta-optics platform in controlling coherent quantum light-sources. Our result also holds great promise for applications like optical sensing, spectral filtering, and few-photon nonlinear optics. Copyright © 2024, The Authors. All rights reserved.

关键词： Continuous wave lasers

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Detection and Classification of Coronary Artery Plaques in Coronary Computed Tomography Angiography Using 3D CNN 1

引用

12th International Workshop on Statistical Atlases and computational Models of the Heart, STACOM 2021 held in conjunction with MICCAI 2021

作者： Chen, Jun-Ting Huang, Yu-Cheng Roth, Holger Yang, Dong Lee, Chih-Kuo Lee, Wen-Jeng Wang, Tzung-Dau Chou, Cheng-Ying Wang, Weichung Graduate Program of Data Science National Taiwan University and Academia Sinica Taipei Taiwan Department of Medical Imaging National Taiwan University Hospital Taipei100 Taiwan NVIDIA BethesdaMD United States Department of Internal Medicine National Taiwan University Hospital Hsin-Chu Branch Hsinchu Taiwan Cardiovascular Center and Divisions of Cardiology and Hospital Medicine Department of Internal Medicine National Taiwan University Hospital Taipei Taiwan Department of Biomechatronics Engineering National Taiwan University Taipei Taiwan Institute of Applied Mathematical Sciences National Taiwan University Taipei Taiwan

ISBN: (数字)9783030937225

ISBN: (纸本)9783030937218

Measuring the existence of coronary artery plaques and stenoses is a standard way of evaluating the risk of cardiovascular diseases. Coronary Computed Tomography Angiography (CCTA) is one of the most common assessments of cardiovascular disease. Manually detecting stenoses over the complete coronary artery tree of each patient takes an expert about 10 min. Previous works about automated detection of plaques required carefully controlling parameters of region-based segmentation algorithms or hand-craft features extraction for machine learning algorithms. Current works presented the feasibility of deep learning algorithms for plaque and stenosis detection. This study aims to develop an efficient workflow for detecting plaques and classification using a 3D convolutional neural network (CNN). Based on a fully convolutional structure, our model has better stability than recurrent layers at the training stage. Furthermore, our method is efficient since the model takes only cross-sectional planes (CSP) images as the input, rather than including other views containing replicate information. For each patient, it takes less than 25 s to perform the whole workflow. The first step of our workflow is to extract CSP images on each control point of a given set of coronary artery centerlines. We then stack several contiguous CSP images together to form a 3D volume, which is the input of the CNN model. The model will predict the type of plaque (soft, mixed, or calcified) at each control point. With this information, we can not only detect the precise location of plaques but also summarize the existence of plaque in each artery segment. In addition, we consider the lumen radius estimation as the next step to approach stenosis detection. © 2022, Springer Nature Switzerland AG.

关键词： Heart

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Photothermal responsivity of van der Waals material-based nanomechanical resonators

arXiv

引用

arXiv 2022年

作者： Aguila, Myrron Albert C. Esmenda, Joshoua C. Wang, Jyh-Yang Lee, Teik-Hui Chen, Yen-Chun Yang, Chi-Yuan Lin, Kung-Hsuan Chang-Liao, Kuei-Shu Kafanov, Sergey Pashkin, Yuri A. Chen, Chii-Dong Department of Engineering and System Science National Tsing Hua University Hsinchu30013 Taiwan Nano Science and Technology Program Taiwan International Graduate Program National Tsing Hua University Academia Sinica Taiwan Institute of Physics Academia Sinica Nankang Taipei11529 Taiwan Department of Physics Lancaster University LancasterLA1 4YB United Kingdom

Nanomechanical resonators made from van der Waals materials (vdW NMRs) provide a new tool for sensing absorbed laser power. The photothermal response of vdW NMRs, quantified from the resonant frequency shifts induced by optical absorption, is enhanced when incorporated in a Fabry-Perot (FP) interferometer. Along with the enhancement comes the dependence of the photothermal response on NMR displacement, which lacks investigation. Here, we address the knowledge gap by studying electromotively driven niobium diselenide drumheads fabricated on highly reflective substrates. We use a FP-mediated absorptive heating model to explain the measured variations of the photothermal response. The model predicts a higher magnitude and tuning range of photothermal responses on few-layer and monolayer NbSe2 drumheads, which outperform other clamped vdW drum-type NMRs at a laser wavelength of 532 nm. Further analysis of the model shows that both the magnitude and tuning range of NbSe2 drumheads scale with thickness, establishing a displacement-based framework for building bolometers using FP-mediated vdW NMRs. © 2022, CC BY.

关键词： Van der Waals forces

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Ultra-Long Homochiral Graphene Nanoribbons Grown Within h-BN Stacks for High-Performance Electronics

arXiv

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arXiv 2024年

作者： Lyu, Bosai Chen, Jiajun Wang, Sen Lou, Shuo Shen, Peiyue Xie, Jingxu Qiu, Lu Mitchell, Izaac Li, Can Hu, Cheng Zhou, Xianliang Watanabe, Kenji Taniguchi, Takashi Wang, Xiaoqun Jia, Jinfeng Liang, Qi Chen, Guorui Li, Tingxin Wang, Shiyong Ouyang, Wengen Hod, Oded Ding, Feng Urbakh, Michael Shi, Zhiwen Shenyang National Laboratory for Materials Science School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China Department of Engineering Mechanics School of Civil Engineering Wuhan University Wuhan430072 China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China Department of Materials Science and Engineering Ulsan National Institute of Science and Technology Ulsan44919 Korea Republic of Graduate School of Carbon Neutrality Ulsan National Institute of Science and Technology Ulsan44919 Korea Republic of Department of Mechanical Engineering Ulsan National Institute of Science and Technology Ulsan44919 Korea Republic of Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai200240 China Department of Physical Chemistry School of Chemistry The Sackler Center for Computational Molecular and Materials Science The Raymond and Beverly Sackler Faculty of Exact Sciences Tel Aviv University Tel Aviv6997801 Israel Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China

Van der Waals encapsulation of two-dimensional materials within hexagonal boron nitride (h-BN) stacks has proven to be a promising way to create ultrahigh-performance electronic devices.1-4 However, contemporary approaches for achieving van der Waals encapsulation, which involve artificial layer stacking using mechanical transfer techniques, are difficult to control, prone to contamination, and unscalable. Here, we report on the transfer-free direct growth of high-quality graphene nanoribbons (GNRs) within h-BN stacks. The as-grown embedded GNRs exhibit highly desirable features being ultralong (up to 0.25 mm), ultranarrow (2V–1s–1 and on-off ratios of up to ~106. This paves the way to the bottom-up fabrication of high-performance electronic devices based on embedded layered materials. Copyright © 2024, The Authors. All rights reserved.

关键词： Boron nitride

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LayOut Loud: An AI-Powered Augmented Reality and Mobile Application for Room Interior Design and Layout Optimization

LayOut Loud: An AI-Powered Augmented Reality and Mobile Appl...

引用

Intelligent Cybernetics Technology & Applications (ICICyTA), International Conference on

作者： John Raphael G. Cuevas John Kenneth R. Rili Anny Neolicia G. Santillan Vivien A. Agustin Mary Grace N. Gonzales Criselle J. Centeno Richard C. Regala Department of Information Technology College of Information Systems and Technology Management Pamantasan ng Lungsod ng Maynila Manila Philippines Department of Computer Science Associate Dean of College of Information Systems and Technology Management Pamantasan ng Lungsod ng Maynila Manila Philippines Department of Information Technology Faculty of College of Engineering and Technology Pamantasan ng Lungsod ng Maynila Manila Philippines Department of Information Technology Director of Graduate Program of College of Information Systems and Technology Management Pamantasan ng Lungsod ng Maynila Manila Philippines Department of Computer Science Computer Lab Administrator of College of Engineering and Technology Pamantasan ng Lungsod ng Maynila Manila Philippines

ISBN: (数字)9798331506490

ISBN: (纸本)9798331506506

LayOut Loud is an AI-powered augmented reality (AR) and mobile application designed to revolutionize room interior design by offering tailored, real-time solutions for layout optimization. The primary objective of this tool is to design AI-powered features that analyze user-provided room dimensions, furniture types, and style preferences. By leveraging advanced algorithms, LayOut Loud generates personalized design suggestions that cater to the individual needs and aesthetic tastes of users, ensuring that each interior design experience is customized and unique. A key goal of the application is to enhance user experience and decision-making through a clustering algorithm. This algorithm categorizes furniture pieces based on their suitability and appearance in living spaces, streamlining the selection process for users. By enabling the visualization of these items in a 3D model, users can make informed decisions about their interior design choices, ensuring that each piece contributes to the overall aesthetic and functional harmony of the space. Additionally, LayOut Loud focuses on improving its AR capabilities by allowing users to capture their room layouts and view virtual furniture arrangements in real time. This feature provides practical, interactive design solutions, empowering users to experiment with different configurations and instantly see how potential changes would appear in their actual living environments. Ultimately, LayOut Loud offers a user-friendly, immersive platform that transforms the way individuals approach interior design.

关键词： Solid modeling Three-dimensional displays Layout Decision making Clustering algorithms Real-time systems User experience Mobile applications Augmented reality Optimization

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Addressing challenges for operating electrochemical solar fuels technologies under variable and diurnal conditions

引用

Frontiers in Energy Research 2024年 12卷

作者： Yap, Kyra M. K. Lee, Sol A. Kistler, Tobias A. Collins, Darci K. Warren, Emily L. Atwater, Harry A. Jaramillo, Thomas F. Xiang, Chengxiang Nielander, Adam C. Department of Chemical Engineering Stanford University StanfordCA United States SUNCAT Center for Interface Science and Catalysis SLAC National Accelerator Laboratory Menlo ParkCA United States Department of Applied Physics and Materials Science California Institute of Technology PasadenaCA United States Chemical Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA United States Chemistry and Nanoscience Center National Renewable Energy Laboratory GoldenCO United States Advanced Energy Systems Graduate Program Colorado School of Mines GoldenCO United States

The outdoor operation of electrochemical solar fuels devices must contend with challenges presented by the cycles of solar irradiance, temperature, and other meteorological factors. Herein, we discuss challenges associated with these fluctuations presented over three timescales, including the effects of diurnal cycling over the course of many days, a single diurnal cycle over the course of hours, and meteorological phenomena that cause fluctuations on the order of seconds to minutes. We also highlight both reaction-independent and reaction-specific effects of variable conditions for the hydrogen evolution reaction and CO2 reduction reaction. We identify key areas of research for advancing the outdoor operation of solar fuels technology and highlight the need for metrics and benchmarks to enable the comparison of diurnal studies across systems and geographical locations. Copyright © 2024 Yap, Lee, Kistler, Collins, Warren, Atwater, Jaramillo, Xiang and Nielander.

关键词： Hydrogen fuels

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A Critical Review of the Impact of Candidate Copy Number Variants on Autism Spectrum Disorders

arXiv

引用

arXiv 2023年

作者： Abedini, Seyedeh Sedigheh Akhavan, Shiva Heng, Julian Alizadehsani, Roohallah Dehzangi, Iman Bauer, Denis C. Rokny, Hamid The Graduate School of Biomedical Engineering UNSW Sydney SydneyNSW2052 Australia Department of Molecular Biology and Genetics Yeni Yuzyil University Istanbul Turkey Curtin Health Innovation Research Institute Curtin University Bentley6845 Australia Deakin University VIC Australia Center for Computational and Integrative Biology Rutgers University CamdenNJ08102 United States Department of Computer Science Rutgers University CamdenNJ08102 United States Sydney Australia Applied BioSciences Faculty of Science and Engineering Macquarie University Macquarie Park Australia

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder (NDD) that is caused by genetic, epigenetic, and environmental factors. Recent advances in genomic analysis have uncovered numerous candidate genes with common and/or rare mutations that increase susceptibility to ASD. In addition, there is increasing evidence that copy number variations (CNVs), single nucleotide polymorphisms (SNPs), and unusual de novo variants negatively affect neurodevelopment pathways in various ways. The overall rate of copy number variants found in patients with autism is 10%-20%, of which 3%-7% can be detected cytogenetically. Although the role of submicroscopic CNVs in ASD has been studied recently, their association with genomic loci and genes has not been properly studied. In this review, we focus on 47 ASD-associated CNV regions and their related genes. Here, we identify 1,632 protein-coding genes and long non-coding RNAs (lncRNAs) within these regions. Among them, 552 are significantly expressed in the brain. Using a list of ASD-associated genes from SFARI, we detect 17 regions containing at least one known ASD-associated protein-coding genes. Of the remaining 30 regions, we identify 24 regions containing at least one protein-coding genes with brain-enriched expression and nervous system phenotype in mouse mutant and one lncRNAs with both brain-enriched expression and upregulation in iPSC to neuron differentiation. Our analyses highlight the diversity of genetic lesions of CNV regions that contribute to ASD and provide new genetic evidence that lncRNA genes may contribute to etiology of ASD. In addition, the discovered CNVs will be a valuable resource for diagnostic facilities, therapeutic strategies, and research in terms of variation priority. © 2023, CC BY-NC-SA.

关键词： Gene expression

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