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Benchmark problems for transcranial ultrasound simulation: Intercomparison of compressional wave models

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arXiv 2022年

作者： Aubry, Jean-Francois Bates, Oscar Boehm, Christian Pauly, Kim Butts Christensen, Douglas Cueto, Carlos Gélat, Pierre Guasch, Lluis Jaros, Jiri Jing, Yun Jones, Rebecca Li, Ningrui Marty, Patrick Montanaro, Hazael Neufeld, Esra Pichardo, Samuel Pinton, Gianmarco Pulkkinen, Aki Stanziola, Antonio Thielscher, Axel Treeby, Bradley Van't Wout, Elwin Physics for Medicine Paris INSERM U1273 ESPCI Paris PSL University CNRS UMR 8063 France Department of Bioengineering Imperial College London Exhibition Road LondonSW7 2AZ United Kingdom Institute of Geophysics ETH Zürich Sonneggstrasse 5 Zürich8092 Switzerland Department of Radiology Stanford University StanfordCA United States Department of Biomedical Engineering Department of Electrical and Computer Engineering University of Utah United States Department of Surgical Biotechnology Division of Surgery and Interventional Science University College London LondonNW3 2PF United Kingdom Earth Science and Engineering Department Imperial College London London United Kingdom Centre of Excellence IT4Innovations Faculty of Information Technology Brno University of Technology Bozetechova 2 Brno612 00 Czech Republic Graduate Program in Acoustics The Pennsylvania State University University Park PA16802 United States Joint Department of Biomedical Engineering University of North Carolina at Chapel Hill North Carolina State University NC United States Department of Electrical Engineering Stanford University StanfordCA United States Zurich Switzerland Laboratory for Acoustics / Noise control Empa Swiss Federal Laboratories for Materials Science and Technology Dubendorf Switzerland Zurich Switzerland Radiology and Clinical Neurosciences Departments Cumming School of Medicine University of Calgary Canada Department of Applied Physics University of Eastern Finland Kuopio70211 Finland Department of Medical Physics and Biomedical Engineering University College London Gower Street LondonWC1E 6BT United Kingdom Technical University of Denmark Denmark Danish Research Center for Magnetic Resonance Copenhagen University Hospital Hvidovre Denmark Institute for Mathematical and Computational Engineering School of Engineering and Faculty of Mathematics Pontificia Universidad Catolica de Chile Santiago Chile

Computational models of acoustic wave propagation are frequently used in transcranial ultrasound therapy, for example, to calculate the intracranial pressure field or to calculate phase delays to correct for skull distortions. To allow intercomparison between the different modeling tools and techniques used by the community, an international working group was convened to formulate a set of numerical benchmarks. Here, these benchmarks are presented, along with intercomparison results. Nine different benchmarks of increasing geometric complexity are defined. These include a single-layer planar bone immersed in water, a multi-layer bone, and a whole skull. Two transducer configurations are considered (a focused bowl and a plane piston), giving a total of 18 permutations of the benchmarks. Eleven different modeling tools are used to compute the benchmark results. The models span a wide range of numerical techniques, including the finite-difference time-domain method, angular-spectrum method, pseudospectral method, boundary-element method, and spectral-element method. Good agreement is found between the models, particularly for the position, size, and magnitude of the acoustic focus within the skull. When comparing results for each model with every other model in a cross comparison, the median values for each benchmark for the difference in focal pressure and position are less than 10% and 1 mm, respectively. The benchmark definitions, model results, and intercomparison codes are freely available to facilitate further comparisons. Copyright © 2022, The Authors. All rights reserved.

关键词： Bone

Performance Improvement of VLC Systems Employing an Amplify-and-Forward Scheme

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Performance Improvement of VLC Systems Employing an Amplify-...

International Symposium on Wireless Personal Multimedia Communications (WPMC)

作者： Marcelo de Oliveira Paulo P. Monteiro Alexandre de Almeida Prado Pohl Graduate Program in Electrical and Computer Engineering Federal University of Technology - Paraná Curitiba Brazil Instituto de Telecomunicações DETI University of Aveiro Aveiro Portugal

ISBN: (数字)9781728154190

ISBN: (纸本)9781728154206

Visible light communications (VLC) are a novel technology that employs LEDs lamps to transfer data between devices, and has the potential to improve wireless communications in the following years. Relay-based cooperative communication, a technique developed for RF communication, takes advantages of spatial diversity without the need of additional resources on the communication transceivers. In this paper, we present a simulation model for the VLC channel with amplify-and-forward cooperative cooperation and show that it can improve the performance of such systems at indoor scenarios.

关键词： Wireless communication Multimedia communication

Levels and trends in the sex ratio at birth in seven provinces of Nepal between 1980 and 2016 with probabilistic projections to 2050: A Bayesian modeling approach

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arXiv 2020年

作者： Chao, Fengqing Samir, K.C. Ombao, Hernando Statistics Program Computer Electrical And Mathematical Sciences And Engineering Division King Abdullah University Of Science And Technology 4700 KAUST Thuwal23955-6900 Saudi Arabia Asian Demographic Research Institute Shanghai University Shangda Road Shanghai200444 China International Institute For Applied Systems Analysis Schlossplatz 1 Laxenburg2361 Austria

Background: The sex ratio at birth (SRB;ratio of male to female births) in Nepal has been reported without imbalance on the national level. However, the national SRB could mask the disparity within the country. Given the demographic and cultural heterogeneities in Nepal, it is crucial to model Nepal SRB on the subnational level. Prior studies on subnational SRB in Nepal are mostly based on reporting observed values from surveys and census, and no study has provided probabilistic projections. We aim to estimate and project SRB for the seven provinces of Nepal from 1980 to 2050 using a Bayesian modeling approach. Methods: We compiled an extensive database on provincial SRB of Nepal, consisting 2001, 2006, 2011, and 2016 Nepal Demographic and Health Surveys and 2011 Census. We adopted a Bayesian hierarchical time series model to estimate and project the provincial SRB, with a focus on modelling the potential SRB imbalance. Results: In 2016, the highest SRB is estimated in Province 5 at 1.102 with a 95% credible interval (1.044, 1.127) and the lowest SRB is in Province 2 at 1.053 (1.035, 1.109). During 1980-2016, the provincial SRB was around the same level as the national SRB baseline of 1.049. The SRB imbalance probabilities in all provinces are generally low and vary from 16% in Province 2 to 81% in Province 5. SRB imbalances are estimated to have begun at the earliest in 2001 in Province 5 with a 95% credible interval (1992, 2022) and the latest in 2017 (1998, 2040) in Province 2. We project SRB in all provinces to begin converging back to the national baseline in the mid-2030s. By 2050, the SRBs in all provinces are projected to be around the SRB baseline level. Conclusion: Our findings imply that the majority of provinces in Nepal have low risks of SRB imbalance for the period 1980-2016. However, we identify a few provinces with higher probabilities of having SRB inflation. The projected SRB is an important illustration of potential future prenatal sex discriminat

关键词： Bayesian networks

Overcoming the surface paradox: Buried perovskite quantum dots in wide-bandgap perovskite thin films

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arXiv 2025年

作者： Zhang, Hao Pasha, Altaf Metcalf, Isaac Zhou, Jianlin Staunstrup, Mathias Zhu, Yunxuan Liao, Shusen Ssennyimba, Ken Chen, Jia-Shiang Reddy, Surya Prakash Thébaud, Simon Hou, Jin Shuai, Xinting Mandani, Faiz Sidhik, Siraj Jones, Matthew R. Ma, Xuedan Balakrishna, R. Geetha Susarla, Sandhya Ginger, David S. Katan, Claudine Kanatzidis, Mercouri G. Bawendi, Moungi G. Natelson, Douglas Tamarat, Philippe Lounis, Brahim Even, Jacky Mohite, Aditya D. Department of Chemical and Biomolecular Engineering Rice University HoustonTX77005 United States Applied Physics Program Smalley‐Curl Institute Rice University HoustonTX77005 United States Centre for Nano and Material Sciences Jain University Jain Global Campus Kanakapura Karnataka Bangalore562112 India Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Université de Bordeaux LP2N Talence France Institut d’Optique CNRS LP2N Talence France Department of Physics and Astronomy Rice University HoustonTX77005 United States Center for Nanoscale Materials Argonne National Laboratory LemontIL60439 United States School for Engineering of Matter Transport and Energy Arizona State University TempeAZ85281 United States UMR 6082 CNRS INSA de Rennes Rennes35708 France Department of Chemistry Rice University HoustonTX77005 United States Department of Chemistry University of Washington Box 351700 SeattleWA98195-1700 United States UMR 6226 Rennes35000 France Department of Chemistry Northwestern University EvanstonIL United States Department of Chemistry Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States

Colloidal perovskite quantum dots (PQDs) are an exciting platform for on-demand quantum, and classical optoelectronic and photonic devices. However, their potential success is limited by the extreme sensitivity and low stability arising from their weak intrinsic lattice bond energy and complex surface chemistry. Here we report a novel platform of buried perovskite quantum dots (b-PQDs) in a three-dimensional perovskite thin-film, fabricated using one-step, flash annealing, which overcomes surface related instabilities in colloidal perovskite dots. The b-PQDs demonstrate ultrabright and stable single-dot emission, with resolution-limited linewidths below 130 μeV, photon-antibunching (g2(0)=0.1), no blinking, suppressed spectral diffusion, and high photon count rates of 104/s, consistent with unity quantum yield. The ultrasharp linewidth resolves exciton fine-structures (dark and triplet excitons) and their dynamics under a magnetic field. Additionally, b-PQDs can be electrically driven to emit single photons with 1 meV linewidth and photon-antibunching (g2(0)=0.4). These results pave the way for on-chip, low-cost single-photon sources for next generation quantum optical communication and sensing. © 2025, CC BY.

关键词： Photons

Bright high-purity quantum emitters in aluminium nitride integrated photonics

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arXiv 2020年

作者： Lu, Tsung-Ju Lienhard, Benjamin Jeong, Kwang-Yong Moon, Hyowon Iranmanesh, Ava Grosso, Gabriele Englund, Dirk Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Photonics Initiative Advanced Science Research Center and Physics Program Graduate Center City University of New York New YorkNY10031 United States Department of Physics Korea University Seoul02841 Korea Republic of

Solid-state quantum emitters (QEs) are fundamental in photonic-based quantum information processing. There is strong interest to develop high-quality QEs in III-nitride semiconductors because of their sophisticated manufacturing driven by large and growing applications in optoelectronics, high voltage power transistors, and microwave amplifiers. Here, we report the generation and direct integration of QEs in an aluminium nitride-based photonic integrated circuit platform. For individual waveguide-integrated QEs, we measure an off-chip count rate exceeding 6 × 104 counts per second (cps) (saturation rate > 8.6 × 104 cps). In an unpatterned thin-film sample, we measure antibunching with g(2)(0) ~ 0.05 and photon count rates exceeding 8 × 105 cps (saturation rate > 1 × 106 cps). Although spin and detailed optical linewidth measurements are left for future work, these results already show the potential for high-quality QEs monolithically integrated in a wide range of III-nitride device technologies that would enable new quantum device opportunities and industrial scalability. Copyright © 2020, The Authors. All rights reserved.

关键词： III-V semiconductors

Artificial confocal microscopy for deep label-free imaging

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arXiv 2021年

作者： Chen, Xi Kandel, Mikhail E. He, Shenghua Hu, Chenfei Lee, Young Jae Sullivan, Kathryn Tracy, Gregory Chung, Hee Jung Kong, Hyun Joon Anastasio, Mark Popescu, Gabriel Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign UrbanaIL United States Department of Computer Science & Engineering Washington University in St. Louis St. LouisMO63130 United States Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Neuroscience Program University of Illinois at Urbana-Champaign UrbanaIL United States Department of Bioengineering University of Illinois at Urbana-Champaign UrbanaIL United States Department of Molecular and Integrative Physiology University of Illinois at Urbana-Champaign UrbanaIL United States Chemical and Biomolecular Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Carl Woese Institute for Genomic Biology University of Illinois at Urbana-Champaign UrbanaIL United States

Enhanced meta-displays using advanced phase-change materials

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arXiv 2021年

作者： Hemmatyar, Omid Abdollahramezani, Sajjad Zeimpekis, Ioannis Lepeshov, Sergey Krasnok, Alex Khan, Asir Intisar Neilson, Kathryn M. Teichrib, Christian Brown, Tyler Pop, Eric Hewak, Daniel W. Wuttig, Matthias Alù, Andrea Muskens, Otto L. Adibi, Ali School of Electrical and Computer Engineering Georgia Institute of Technology 778 Atlantic Drive NW AtlantaGA30332-0250 United States Zepler Institute Faculty of Engineering and Physical Sciences University of Southampton SouthamptonSO17 1BJ United Kingdom ITMO University St. Petersburg197101 Russia Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical Engineering Department of Materials Science and Engineering Precourt Institute for Energy Stanford University StanfordCA94305 United States Physikalisches Institut IA RWTH Aachen Sommerfeldstrasse 14 Aachen52074 Germany Physics Program Graduate Center City University of New York New YorkNY10016 United States Physics and Astronomy Faculty of Engineering and Physical Sciences University of Southampton SouthamptonSO17 1BJ United Kingdom

Structural colors generated due to light scattering from static all-dielectric metasurfaces have successfully enabled high-resolution, high-saturation, and wide-gamut color printing applications. Despite recent advances, most demonstrations of these structure-dependent colors lack post-fabrication tunability. This hinders their applicability for front-end dynamic display technologies. Phase-change materials (PCMs), with significant contrast of their optical properties between their amorphous and crystalline states, have demonstrated promising potentials in reconfigurable nanophotonics. Herein, we leverage tunable all-dielectric reflective metasurfaces made of newly emerged classes of low-loss optical PCMs, i.e., antimony trisulphide (Sb2S3) and antimony triselenide (Sb2Se3), with superb characteristics to realize switchable, high-saturation, high-efficiency and high-resolution dynamic meta-pixels. Exploiting polarization-sensitive building blocks, the presented meta-pixel can generate two different colors when illuminated by either one of two orthogonally polarized incident beams. Such degrees of freedom (i.e., material phase and polarization state) enable a single reconfigurable metasurface with fixed geometrical parameters to generate four distinct wide-gamut colors. We experimentally demonstrate, for the first time, an electrically-driven micro-scale display through the integration of phase-change metasurfaces with an on-chip heater formed by transparent conductive oxide. Our experimental findings enable a versatile platform suitable for a wide range of applications, including tunable full-color printing, enhanced dynamic displays, information encryption, and anti-counterfeiting. © 2021, CC BY.

关键词： Light scattering

Deciphering Domestic Energy Demand through Household Electricity and Gas Consumption

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Energy and Built Environment

Energy and Built Environment 2025年

作者： Sari Khdhaer Mukhlif Ahmed K. Nassar Omer Al-Dulaimi Hassan Falah Fakhruldeen Talib Munshid Hanoon Feryal Ibrahim Jabbar Doaa H. Khalaf Sameer Algburi Technical College of Engineering Al-Bayan University Baghdad 10011 Iraq. Policy Planning and Development Program Department of International Affairs College of Arts and Sciences Qatar University Doha 2713 Qatar. Electrical Technical College Al-Farahidi University Baghdad 10001 Iraq. Computer Techniques Engineering Department Faculty of Information Technology Imam Ja’afar Al-Sadiq University Baghdad 10011 Iraq Mazaya University College Nasiriyah 64001 Iraq Medical Physics Department College of Sciences Al-Mustaqbal University Babil 51001 Iraq. Design Department Al-Turath University College Baghdad 10011 Iraq College of Engineering Al-Kitab University Kirkuk 36015 Iraq

This study investigates residential electricity and gas demand in Iraq using smart meter data from 15,000 households between 2019 and 2023. The primary objective is to analyze temporal energy consumption patterns, focusing on the impact of environmental, behavioral, and household-specific factors. The results show that electricity consumption peaks during the afternoon, particularly between 12:00 and 14:00, with average usage reaching 2.3 to 2.6 kWh, while gas consumption increases in the winter months, especially in the early morning hours, driven by heating and cooking activities. The analysis of weekend versus weekday consumption reveals a 6.4% increase in electricity and a 3.1% rise in gas usage on weekends, indicating shifts in behavioral energy usage patterns. The study finds that predicted values closely match observed data, with a deviation of only 5% for electricity and 7% for gas, showcasing high model accuracy. The concept of "variability" is clarified as fluctuations in demand across different times of the day, which were reduced in households with efficient appliances, as identified from household energy audits linked to smart meters. The dataset also provides insights into the use of energy-efficient appliances, collected from utility-linked surveys and integrated household registration data. The findings offer valuable insights into demand-side energy management and are particularly relevant to urban Iraqi households but may also inform demand forecasting in similar regions with comparable climates and energy use behaviors.

关键词： Household energy consumption Electricity and gas demand patterns Energy clustering analysis Predictive energy modeling

In situ observations of interfacial evolutions in solid-state lithium battery with sulfide-based solid electrolyte

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In situ observations of interfacial evolutions in solid-stat...

IEEE Conference on Nanotechnology

作者： Akshay Kakar Fang Hao Yanliang Liang Yan Yao Zheng Fan Materials Science and Engineering Program University of Houston Houston TX USA Department of Electrical and Computer Engineering University of Houston Houston TX USA Department of Engineering Technology University of Houston Houston TX USA

Solid electrolytes provide for safe rechargeable lithium batteries and allow the batteries with lithium metal anodes to possess higher energy densities than those of traditional liquid electrolyte based batteries. However, the structural evolution-induced interfacial failures during the electrochemical cycling have not been explored at a fundamental level. In this report, a practical setup is developed for in situ detection of the electrochemical reaction- induced micro and nanoscale morphological changes along the battery's interface. We have focused on the anode interface with lithium metal as the electrode and solid sulfide as the electrolyte, while monitoring an inflating phenomenon in the electrolyte during the lithium plating. This observation suggests that the lithium dendrite formation as well as the lithium deposition in the porous structures drives the volume expansion of the solid electrolyte. This rare finding offers a fresh perspective, indicating a new impact of the lithium plating in sulfide electrolyte, which does not accord with the conventional structural evolution model at the electrode-solid electrolyte interface. This study contributes significant insights into the mechanism of the interfacial phenomena in sulfide solid-state battery and paves the way for their advanced engineering.

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