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2024 Laser Science, LS 2024

作者： Xu, Yuan Liu, Jiangnan Singh, Anshuman Tsai, Cheng-Chia Malek, Stephanie C. Shin, Walter Jin Wu, Jiahao Zhu, Freddie Liu, David Yu, Nanfang Mi, Zetian Soltani, Mohammad Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States Raytheon BBN Technologies CambridgeMA02138 United States

We fabricated GaN metasurfaces doped with InGaN quantum dots by templated molecular beam epitaxy (MBE) that support tunable high Q-factor quasi-bound states in the continuum (q-BICs) and demonstrated efficient optical... 详细信息

关键词： Gallium nitride

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Dynamics of self-hybridized exciton–polaritons in 2D halide perovskites

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Light(Science & Applications) 2024年第1期13卷 13-22页

作者： Surendra B.Anantharaman Jason Lynch Christopher E.Stevens Christopher Munley Chentao Li Jin Hou Hao Zhang Andrew Torma Thomas Darlington Francis Coen Kevin Li Arka Majumdar PJames Schuck Aditya Mohite Hayk Harutyunyan Joshua R.Hendrickson Deep Jariwala Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA19104USA KBR Inc. BeavercreekOH45431USA Air Force Research Laboratory Sensors DirectorateWright-Patterson Air Force BaseOH45433USA Department of Physics University of WashingtonSeattleWA98195USA Department of Physics Emory UniversityAtlantaGA30322USA Department of Chemical and Biomolecular Engineering Rice UniversityHoustonTX77005USA Department of Materials Science and Nanoengineering Rice UniversityHoustonTX77005USA Applied Physics Program Smalley‐Curl InstituteRice UniversityHoustonTX77005USA Department of Mechanical Engineering Columbia UniversityNew YorkNY10027USA Department of Electrical and Computer Engineering University of WashingtonSeattleWA98195USA

Excitons,bound electron–hole pairs,in two-dimensional hybrid organic inorganic perovskites(2D HOIPs)are capable of forming hybrid light-matter states known as exciton-polaritons(E–Ps)when the excitonic medium is confined in an optical *** the case of 2D HOIPs,they can self-hybridize into E–Ps at specific thicknesses of the HOIP crystals that form a resonant optical cavity with the ***,the fundamental properties of these self-hybridized E–Ps in 2D HOIPs,including their role in ultrafast energy and/or charge transfer at interfaces,remain ***,we demonstrate that>0.5µm thick 2D HOIP crystals on Au substrates are capable of supporting multiple-orders of self-hybridized E–P *** E–Ps have high Q factors(>100)and modulate the optical dispersion for the crystal to enhance sub-gap absorption and *** varying excitation energy and ultrafast measurements,we also confirm energy transfer from higher energy E–Ps to lower energy E–***,we also demonstrate that E–Ps are capable of charge transport and transfer at *** findings provide new insights into charge and energy transfer in E–Ps opening new opportunities towards their manipulation for polaritonic devices.

关键词： charge polar excitation

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Approximate Selection with Unreliable Comparisons in Optimal Expected Time 40

Approximate Selection with Unreliable Comparisons in Optimal...

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40th International Symposium on Theoretical Aspects of Computer Science, STACS 2023

作者： Huang, Shengyu Liu, Chih-Hung Rutschmann, Daniel Department of Computer Science EPFL Lausanne Switzerland Department of Electrical Engineering National Taiwan University Taipei Taiwan Department of Applied Mathematics and Computer Science Technical University of Denmark Copenhagen Denmark

ISBN: (纸本)9783959772662

Given n elements, an integer k ≤ n/2 and a parameter Ε ≥ 1/n , we study the problem of selecting an element with rank in (k − nΕ, k + nΕ] using unreliable comparisons where the outcome of each comparison is incorrect independently with a constant error probability, and multiple comparisons between the same pair of elements are independent. In this fault model, the fundamental problems of finding the minimum, selecting the k-th smallest element and sorting have been shown to require Θ(n log 1/Q), Θ(n log k/Q) and Θ(n log n/Q) comparisons, respectively, to achieve success probability 1 − Q [9]. Considering the increasing complexity of modern computing, it is of great interest to develop approximation algorithms that enable a trade-off between the solution quality and the number of comparisons. In particular, approximation algorithms would even be able to attain a sublinear number of comparisons. Very recently, Leucci and Liu [23] proved that the approximate minimum selection problem, which covers the case that k ≤ nΕ, requires expected Θ(Ε−1 log 1/Q) comparisons, but the general case, i.e., for nΕ −2 log 1/Q) comparisons to achieve success probability at least 1 − Q. For k = nΕ, the number of comparisons is O(Ε−1 log 1/Q), matching Leucci and Liu’s result [23], whereas for k = n/2 (i.e., approximating the median), the number of comparisons is O(Ε−2 log 1/Q). We also prove that even in the absence of comparison faults, any randomized algorithm with success probability at least 1 − Q performs expected Ω(min{n, k/n Ε−2 log 1/Q }) comparisons. As long as n is large enough, i.e., when n = Ω(k/n Ε−2 log 1/Q), our lower bound demonstrates the optimality of our algorithm, which covers the possible range of attaining a sublinear number of comparisons. Surprisingly, for constant Q, our algorithm performs expected O(k/n Ε−2) comparisons, matching the best possible approximation algorithm in the absence of computation faults. In contrast, for the exact selection problem, the expe

关键词： Approximation algorithms

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Thermally stratified flow of hybrid nanofluids with radiative heat transport and slip mechanism: multiple solutions

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Communications in Theoretical Physics 2022年第1期74卷 142-151页

作者： Rai Sajjad Saif Hashim Maria Zaman Muhammad Ayaz Department of Humanities and Sciences School of Electrical Engineering and Computer Science(SEECS)National University of Sciences and Technology(NUST)IslamabadPakistan Department of Pure&Applied Mathematics University of Haripur22620HaripurPakistan Department of Mathematics&Statistics Riphah International University IslamabadPakistan Department of Mathematics Abdul Wali Khan UniversityMardan23200Pakistan

Research on flow and heat transfer of hybrid nanofluids has gained great significance due to their efficient heat transfer *** fact,hybrid nanofluids are a novel type of fluid designed to enhance heat transfer rate and have a wide range of engineering and industrial *** by this evolution,a theoretical analysis is performed to explore the flow and heat transport characteristics of Cu/Al_(2)O_(3) hybrid nanofluids driven by a stretching/shrinking ***,this work focuses on the physical impacts of thermal stratification as well as thermal radiation during hybrid nanofluid flow in the presence of a velocity slip *** mathematical modelling incorporates the basic conservation laws and Boussinesq *** formulation gives a system of governing partial differential equations which are later reduced into ordinary differential equations via dimensionless *** efficient numerical solver,known as bvp4c in MATLAB,is utilized to acquire multiple(upper and lower)numerical solutions in the case of shrinking *** computed results are presented in the form of flow and temperature *** most significant findings acquired from the current study suggest that multiple solutions exist only in the case of a shrinking surface until a critical/turning ***,solutions are unavailable beyond this turning point,indicating flow *** is found that the fluid temperature has been impressively enhanced by a higher nanoparticle volume fraction for both *** the other hand,the outcomes disclose that the wall shear stress is reduced with higher magnetic field in the case of the second *** simulation outcomes are in excellent agreement with earlier research,with a relative error of less than 1%.

关键词： multiple numerical solutions hybrid nanofluids thermal radiation thermal stratification slip conditions heat transfer

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Fully relativistic many-body perturbation energies,transition properties,and lifetimes of lithium-like iron Fe XXIV

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Chinese Physics B 2023年第10期32卷 90-99页

作者：李双赵敏刘国庆胡昌宝潘国柱 School of Electrical and Opto-electronic Engineering West Anhui UniversityLu'an 237012China College of Mechanical and Electronic Engineering Fujian Agriculture and Forestry UniversityFuzhou 350002China Institute of Applied Physics and Computational Mathematics Beijing 100088China Shanghai EBIT Laboratory Institute of Modern PhysicsDepartment of Nuclear Science and TechnologyFudan UniversityShanghai 200433China

Employing the advanced relativistic configuration interaction(RCI)combined with the many-body perturbation theory(RMBPT)method,we report energies and lifetime values for the lowest 35 energy levels from the(1s^(2))nl configurations(where the principal quantum number n=2–6 and the angular quantum number l=0,...,n-1)of lithium-like iron Fe XXIV,as well as complete data on the transition wavelengths,radiative rates,absorption oscillator strengths,and line strengths between the *** the allowed(E1)and forbidden(magnetic dipole M1,magnetic quadrupole M2,and electric quadrupole E2)ones are *** detailed comparisons with previous results,we assess the overall accuracies of present RMBPT results to be likely the most precise ones to *** interaction effects are found to be very important for the energies and radiative properties for the *** present RMBPT results are valuable for spectral line identification,plasma modeling,and diagnosing.

关键词： relativistic many-body perturbation multi-reference configuration radiative rates lifetime

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Advancements in Geopolymer Concrete for Marine Infrastructure: An Optimization of Performance Considering Workability, Compressive Strength, Capillary Water Absorption, Porosity, and Chloride Migration

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Iranian Journal of Science and Technology - Transactions of Civil engineering 2024年 1-14页

作者： Shahedan, Noor Fifinatasha Hadibarata, Tony Jusoh, Muhammad Noor Hazwan Isia, Ismallianto Bouaissi, Aissa Juwono, Filbert Hilman Nawawi, Natasha Ahmad Kusumaningrum, Hermin Pancasakti Muslim, Abrar Hidayat, Topik Environment Engineering Program Curtin University Malaysia Miri CDT 250 Malaysia School of Engineering University of Plymouth Plymouth PL4 8AA United Kingdom Department of Electrical and Electronic Engineering Xi’an Jiaotong – Liverpool University Suzhou China School of Mechanical Engineering College of Engineering Universiti Teknologi MARA Shah Alam 40450 Malaysia Biotechnology Study Program Department of Biology Faculty of Science and Mathematics Universitas Diponegoro Semarang Indonesia Department of Chemical Engineering Faculty of Engineering Universitas Syiah Kuala Banda Aceh Indonesia Biology Study Program Faculty of Mathematics and Science Education Universitas Pendidikan Indonesia Bandung Indonesia

This research investigates the effectiveness of geopolymer concrete incorporating fly ash in environments rich in chlorides;in contrast to conventional Portland cement concrete (OPC). The study emphasizes essential characteristics such as workability, mechanical strength, capillary water absorption, open porosity, and chloride migration. The experiments demonstrated that geopolymer concrete exhibits a 30% enhancement in slump values, reflecting improved workability, and its compressive strength rose by 14.90–23.94% when compared with OPC. A significant reduction in binder content led to a notable decrease in capillary water absorption, highlighting a positive impact on long-term durability. With time, geopolymer concrete showed a reduction in open porosity and chloride migration coefficient, indicating better resistance to chloride penetration in marine settings. Although these outcomes underscore the potential of geopolymer concrete to improve structural durability, especially in marine infrastructure, additional optimization is required to tackle its relatively higher capillary water absorption and chloride migration during the initial stages. These results contribute to the ongoing investigation of sustainable building materials, offering valuable insights into geopolymer concrete’s ability to endure severe chloride exposure and serve as a durable solution for corrosion management in marine infrastructure. © The Author(s), under exclusive licence to Shiraz University 2024.

关键词： Durability Geopolymer concrete Marine environments Mix design Sustainable construction

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Development of LED Lighting for Microalgae Propagation with Emission Spectrum Having Broader Emission Peaks

Development of LED Lighting for Microalgae Propagation with ...

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2024 IEEE Sustainable Smart Lighting World Conference and Expo, LS24 2024

作者： Hosoda, Nobuaki Murata, Takashi Misu, Takayuki Kanagawa Institute of Technology Graduate School of Engineering Master's Degree Program in Electrical and Electronic Engineering Atsugi Kanagawa243-0292 Japan Kanagawa Institute of Technology Faculty of Engineering Department of Applied Chemistry and Bioscience Atsugi Kanagawa243-0292 Japan Kanagawa Institute of Technology Faculty of Engineering Department of Electrical and Electronic Engineering Atsugi Kanagawa243-0292 Japan

ISBN: (纸本)9798331540197

In this study, we aimed to develop LED lighting with an emission spectrum effective for microalgae propagation, and fabricated LED lighting with Phosphor layer RGB, which has peaks in the red, green, and blue wavelength bands, and Phosphor layer RG'B', which has broader peaks in the red, green, and blue wavelength bands. In order to examine the effect of microalgae propagation, Closterium ehrenbergii samples prepared at different dilution rates were irradiated with LED illumination light of Phosphor layer RG'B' and Phosphor layer RGB, respectively, for 7 days, and their propagation rates were compared. The results of the experiment showed that Phosphor layer RG'B' produced a higher propagation rate than Phosphor layer RGB. © 2024 IEEE.

关键词： Light emitting diodes

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Multilevel Converters for Doubly-Fed Induction Generator Wind Energy Systems: A Review 13

Multilevel Converters for Doubly-Fed Induction Generator Win...

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13th International Renewable Energy Congress, IREC 2022

作者： Amorim, A.E.A. Encarnacao, L.F. Yahyaoui, I. Department of Electrical Engineering ES Sao Mateus Brazil Department of Electrical Engineering Brazil Applied Mathematics Materials Science and Engineering and Electronic Technology School of Experimental Sciences and Technology Madrid Spain

ISBN: (纸本)9781665488976

This research paper presents a review for multilevel power electronics converters topologies which are used for wind energy conversion systems based in Doubly-Fed Induction Generator (DFIG). In fact, the paper focuses on the most principal technologies used to allow the power generated by the wind turbines to be increased and to enhance the fault supportability. © 2022 IEEE.

关键词： Wind power

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Shedding Light on Problems with Hyperbolic Graph Learning

arXiv

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arXiv 2024年

作者： Katsman, Isay Gilbert, Anna Department of Applied Mathematics Yale University United States Department of Applied Mathematics Department of Statistics Data Science Department of Electrical Engineering Yale University United States

Recent papers in the graph machine learning literature have introduced a number of approaches for hyperbolic representation learning. The asserted benefits are improved performance on a variety of graph tasks, node classification and link prediction included. Claims have also been made about the geometric suitability of particular hierarchical graph datasets to representation in hyperbolic space. Despite these claims, our work makes a surprising discovery: when simple Euclidean models with comparable numbers of parameters are properly trained in the same environment, in most cases, they perform as well, if not better, than all introduced hyperbolic graph representation learning models, even on graph datasets previously claimed to be the most hyperbolic (Chami et al., 2019) as measured by Gromov δ-hyperbolicity (i.e., perfect trees). This observation gives rise to a simple question: how can this be? We answer this question by taking a careful look at the field of hyperbolic graph representation learning as it stands today, and find that a number of papers fail to diligently present baselines, make faulty modelling assumptions when constructing algorithms, and use misleading metrics to quantify geometry of graph datasets. We take a closer look at each of these three problems, elucidate the issues, perform an analysis of methods, and introduce a parametric family of benchmark datasets to ascertain the applicability of (hyperbolic) graph neural networks. Copyright © 2024, The Authors. All rights reserved.

关键词： Contrastive Learning

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A Performance Study on Deep Learning Covid-19 Prediction through Chest X-Ray Image with ResNet50 Model 2

A Performance Study on Deep Learning Covid-19 Prediction thr...

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2nd International Conference on Advances in electrical, Computing, Communication and Sustainable Technologies, ICAECT 2022

作者： Kumar, Dhirendra Sharma, Pulkit Anupama, Anupama Sharma, Parth Delhi Technological University Department of Applied Mathematics Delhi India Delhi Technological University Department of Electrical Engineering Delhi India

ISBN: (纸本)9781665411202

The COVID-19 epidemic has claimed many lives throughout the world and constitutes an unprecedented public health concern. The key challenge in early detection of the corona virus is early detection. And the main obstacle was the similarity of COVID-19 symptoms to flu symptoms. With the goal of saving human lives and stemming the spread of a worldwide pandemic, an accurate and speedy analysis of COVID-19-induced pneumonia has now taken centre stage. Responding this urgent concern and to reduce the burden as well as chances of faulty manual diagnosis, several deep learning approaches are developed to conduct early diagnosis. Based on the availability of reliable patient's records, an accepted technique is pre-trained deep learning prediction approach through patient's chest X-Rays. Convenience of this approach led development of a number of novel deep learning-based lung screening technologies. However, little emphasis is placed on ensuring the quality of their output. Pre-trained deep learning systems will be used in this project to evaluate their ability to recognise and diagnose disorders. To categorise COVID and normal pictures, a neural network-based ResNet50 architecture is presented. The implementation is based on the normal, COVID, and lung opacity datasets. For data pre-processing, ImageDataGenerator is used, which rescales, flips, and modifies the range to meet the model. To categorise the x- ray images, the suggested method ResNet50 architecture is used. Performance matrices like precision, accuracy, recall, as well as F1-score are examined to verify the algorithm's usefulness. The suggested technique has an accuracy of 80%, indicating that the proposed model is quite good in classifying COVID and normal x-ray pictures. This research will have a significant influence on real-time since it will accurately diagnose COVID in less time, perhaps lowering the mortality rate. © 2022 IEEE.

关键词： COVID-19

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