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Transition from Diffusive to Superdiffusive Transport in Carbon Nanotube Networks via Nematic Order Control

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arXiv 2023年

作者： Wais, Michael Bagsican, Filchito Renee G. Komatsu, Natsumi Gao, Weilu Serita, Kazunori Murakami, Hironaru Held, Karsten Kawayama, Iwao Kono, Junichiro Battiato, Marco Tonouchi, Masayoshi Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore Institute for Solid State Physics TU Wien Vienna1040 Austria Institute of Laser Engineering Osaka University Osaka Suita565-0871 Japan Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Electrical and Computer Engineering University of Utah Salt Lake CityUT84112 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Department of Material Science and NanoEngineering Rice University HoustonTX77005 United States

The one-dimensional confinement of quasiparticles in individual carbon nanotubes (CNTs) leads to extremely anisotropic electronic and optical properties. In a macroscopic ensemble of randomly oriented CNTs, this anisotropy disappears together with other properties that make them attractive for certain device applications. The question however remains if not only anisotropy, but other types of behaviours are suppressed by disorder. Here, we compare the dynamics of quasiparticles under strong electric fields in aligned and random CNT networks using a combination of terahertz emission and photocurrent experiments and out-of-equilibrium numerical simulations. We find that the degree of alignment strongly influences the excited quasiparticles’ dynamics, rerouting the thermalisation pathways. This is, in particular, evidenced in the high-energy, high-momentum electronic population (probed through the formation of low energy excitons via exciton impact ionization) and the transport regime evolving from diffusive to superdiffusive. Copyright © 2023, The Authors. All rights reserved.

关键词： Anisotropy

Life Cycle Assessment for Servitization: A Case Study on Current Mobility Services

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Procedia Manufacturing 2020年 43卷 72-79页

作者： Chalaka Fernando Vi Kie Soo Matthew Doolan Research School of Electrical Energy and Material Engineering College of Engineering and Computer Science The Australian National University Canberra ACT 2601 Australia

The use of mobility services is increasing. There is a suggestion that this will present a range of different sustainable outcomes. Life Cycle Assessment is commonly used to assess the impact of mobility products, such as cars, as a function of distance. However, it is unclear how this approach applies to different servitization models with varying occupancy levels. This paper assesses the effect of different occupancy rates on life cycle impact of current mobility services: taxi and carpooling compared to the vehicle ownership model using two functional units: vehicle kilometre and passenger kilometre. Case studies were carried out in Europe and the US to assess the global warming potential. This study showed that the use impact normalized to *** is similar for different servitization modes but vary significantly when normalized to ***. The environmental impact of personal transportation can be reduced significantly with the increase in occupancy levels for mobility services.

关键词： life cycle assessment servitization shared mobility mobility as a service (MaaS) occupancy passenger kilometre

engineering the Impact of Phonon Dephasing on the Coherence of a WSe2 Single-Photon Source via Cavity Quantum Electrodynamics

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Physical Review Letters 2024年第20期132卷 206903-206903页

作者： Victor N. Mitryakhin Alexander Steinhoff Jens-Christian Drawer Hangyong Shan Matthias Florian Lukas Lackner Bo Han Falk Eilenberger Seth Ariel Tongay Kenji Watanabe Takashi Taniguchi Carlos Antón-Solanas Ana Predojević Christopher Gies Martin Esmann Christian Schneider Carl von Ossietzky Universität Oldenburg Fakultät V Institut für Physik 26129 Oldenburg Germany Institute for Theoretical Physics and Bremen Center for Computational Material Science University of Bremen 28334 Bremen Germany University of Michigan Department of Electrical Engineering and Computer Science Ann Arbor Michigan 48109 USA Friedrich Schiller University Jena Jena Germany Materials Science and Engineering School for Engineering of Matter Transport and Energy Arizona State University Tempe Arizona 85287 USA Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Depto. de Física de Materiales Instituto Nicolás Cabrera Instituto de Física de la Materia Condensada Universidad Autónoma de Madrid 28049 Madrid Spain Department of Physics Stockholm University 10691 Stockholm Sweden

Emitter dephasing is one of the key issues in the performance of solid-state single-photon sources. Among the various sources of dephasing, acoustic phonons play a central role in adding decoherence to the single-photon emission. Here, we demonstrate that it is possible to tune and engineer the coherence of photons emitted from a single WSe2 monolayer quantum dot via selectively coupling it to a spectral cavity resonance. We utilize an open cavity to demonstrate spectral enhancement, leveling, and suppression of the highly asymmetric phonon sideband, finding excellent agreement with a microscopic description of the exciton-phonon dephasing in a truly two-dimensional system. Moreover, the impact of cavity tuning on the dephasing is directly assessed via optical interferometry, which points out the capability to utilize light-matter coupling to steer and design dephasing and coherence of quantum emitters in atomically thin crystals.

关键词： Acoustic phonons Excitons Open quantum systems & decoherence Optical & microwave phenomena Optical coherence Photonics Single photon sources Quantum dots Transition metal dichalcogenides Cavity resonators Optical interferometry Optical pumping Photoluminescence

Thermal Emittance Isolation by Cathode Retraction

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arXiv 2024年

作者： Sims, Benjamin Lewellen, John W. Ting, Xu Baryshev, Sergey V. Department of Electrical and Computer Engineering Michigan State University MI48824 United States Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Facility for Rare Isotope Beams Michigan State University East LansingMI48824 United States Accelerator Operations and Technology Division Los Alamos National Laboratory NM87545 United States Department of Chemical Engineering and Material Science Michigan State University MI48824 United States

In this work, a combination of cathode retraction and two-slit emittance measurement technique is proposed as an advanced means to individually modify emittance growth components, specifically, rf injector fringe fields, to isolate and directly measure the thermal emittance, the fundamental beam emittance metric for an electron beam. A case study of the LCLS-II-HE Low Emittance Injector (LEI), a state-of-the-art superconducting radiofrequency (SRF) gun, designed for LCLS-II HE upgrade is used to showcase the power of the two-slit technique. Particularly, it is demonstrated that generating a high resolution phase-space distribution map, dominated by the intrinsic emittance of the electron bunch, is possible. This result goes beyond the normal single-parameter distribution characterizations (e.g. RMS emittance and Twiss parameters) provided by the solenoid scan. One key feature making this technique work (and in the end practically useful) is the ability to retract the cathode, because it provides the ability to compensate for radiofrequency (rf) de-focusing. It is demonstrated how the cathode retraction can serve as an additional optimisation tool for tailoring the routine performance of the photoinjector. We posit that a variable position cathode may be a useful method for optimizing photoinjector performance across multiple parameters regimes. © 2024, CC BY.

关键词： Phase space methods

Dual-mode rf cavity: design, tuning and performance

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arXiv 2024年

作者： Sims, Benjamin Sims, David Baryshev, Sergey V. Lewellen, John W. Department of Electrical and Computer Engineering Michigan State University MI48824 United States Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Facility for Rare Isotope Beams Michigan State University East LansingMI48824 United States Department of Chemical Engineering and Material Science Michigan State University MI48824 United States Accelerator Operations and Technology Division Los Alamos National Laboratory NM87545 United States

We present the design and characterization of a dual-mode radiofrequency (rf) cavity, a novel electromagnetic structure with potential benefits such as compactness, efficiency, cost reduction and multifunctionality. The cavity was designed to balance the dual-mode structure considering several factors, such as mode frequencies, quality factor (Q-factor), and minimizing cross talk between couplers. We preformed various tests to verify that this cavity preformed as expected compared to simulated results. As exampled here, a combination of the the fundamental mode TM010 and the TM011 mode, tuned to a harmonic of the fundamental, was realized to linearize the off-crest electric field, thereby enabling concurrent bunching and acceleration of charged particle (e.g. electrons) beam in high power systems. The reduction in the number of cavities required to bunch and accelerate promises cost and space savings over conventional approaches. This research lays the foundation for further exploration of multi-mode cavity applications and optimization for specific use cases, with potential implications for a wide range of fields including quantum information platforms. © 2024, CC BY.

关键词： Q factor measurement

Frequency Chirped Pulse-Based Methane Sensing with Inter-Pulse Calibration 27

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Frequency Chirped Pulse-Based Methane Sensing with Inter-Pul...

27th International Conference on Optical Fiber Sensors, OFS 2020

作者： Shi, Guannan Homa, Daniel Su, Xu Pickrell, Gary Wang, Anbo Zhu, Yizheng Center for Photonics Technology The Bradley Department of Electrical and Computer Engineering Virginia Tech BlacksburgVA24061 United States Center for Photonics Technology Department of Material Science and Engineering Virginia Tech BlacksburgVA24061 United States

A chirped pulse-based gas sensing technique was developed. With a short, 11.2 ns frequency chirped pulse generating differential absorption within the pulse duration, inter-pulse calibrated methane sensing up to 20.5%... 详细信息

ISBN: (纸本)9781557523075

关键词： Methane

Gaussian Process-based Active Learning for Efficient Cardiovascular Disease Inference

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Gaussian Process-based Active Learning for Efficient Cardiov...

IEEE International Conference on Bioinformatics and Biomedicine (BIBM)

作者： Stavroula C. Tassi Konstantinos D. Polyzos Dimitrios I. Fotiadis Antonis I. Sakellarios Department of Material Science and Engineering Unit of Medical Technology and Intelligent Information Systems (MEDLAB) University of Ioannina Ioannina Greece Department of Mechanical and Aeronautics Engineering University of Patras Patras Greece Department of Electrical and Computer Engineering University of Minnesota Minnesota USA Biomedical Reasearch Institute Foundation for Research and Technology-Hellas(FORTH) Ioannina Greece Department of Mechanical and Aeronautics Engineering Laboratory of Biomechanics and Biomedical Engineering University of Patras Patras Greece Unit of Medical Technology and Intelligent Information Systems (MEDLAB) University of Ioannina Ioannina Greece

Cardiovascular disease (CVD) poses a significant global health challenge, and accurate inference methods are vital for early detection and intervention. However, the quality of prediction relies heavily on the availability of labeled data, which are often limited in medical applications. To cope with the challenge of limited labeled data, we are the first to propose an active learning (AL) approach that leverages a weighted ensemble of Gaussian processes to effectively infer CVD by strategically selecting the few most informative data points to label. Through experiments conducted on the SMARTool dataset, we demonstrate the effectiveness of the advocated approach, achieving superior performance in CVD inference compared to baseline methods. Our findings highlight the potential impact of the proposed AL framework in CVD diagnosis and treatment clinical cases, particularly in scenarios where labeled data are scarce, due to data confidentiality concerns or high sampling costs.

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Room-temperature multiple ligands-tailored SnO_(2) quantum dots endow in situ dual-interface binding for upscaling efficient perovskite photovoltaics with high V_(OC)

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Light(science & Applications) 2021年第12期10卷 2467-2481页

作者： Zhiwei Ren Kuan Liu Hanlin Hu Xuyun Guo Yajun Gao Patrick W.K.Fong Qiong Liang Hua Tang Jiaming Huang Hengkai Zhang Minchao Qin Li Cui Hrisheekesh Thachoth Chandran Dong Shen Ming-Fai Lo Annie Ng Charles Surya Minhua Shao Chun-Sing Lee Xinhui Lu Frédéric Laquai Ye Zhu Gang Li Department of Electronic and Information Engineering Research Institute for Smart Energy(RISE)Guangdong-Hong Kong-Macao(GHM)Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and DevicesThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Department of Electrical and Computer Engineering Nazarbayev UniversityNur-SultanKazakhstan The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057China Hoffmann Institute of Advanced Materials Shenzhen Polytechnic7098 Liuxian BoulevardShenzhen 518055China Department of Applied Physics The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Department of Chemical and Biological Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina King Abdullah University of Science and Technology(KAUST) KAUST Solar Center(KSC)Physical Sciences and Engineering Division(PSE)Material Science and Engineering Program(MSE)Thuwal 23955-6900Kingdom of Saudi Arabia Department of Physics The Chinese University of Hong KongShatin 999077 Hong KongChina Center of Super-Diamond and Advanced Films(COSDAF) Department of ChemistryCity University of Hong KongHong KongChina

The benchmark tin oxide(SnO_(2))electron transporting layers(ETLs)have enabled remarkable progress in planar perovskite solar cell(PSCs).However,the energy loss is still a challenge due to the lack of“hidden interface”*** report a novel ligand-tailored ultrafine SnO_(2) quantum dots(QDs)via a facile rapid room temperature ***,the ligand-tailored SnO_(2) QDs ETL with multi-functional terminal groups in situ refines the buried interfaces with both the perovskite and transparent electrode via enhanced interface binding and perovskite *** novel ETLs induce synergistic effects of physical and chemical interfacial modulation and preferred perovskite crystallization-directing,delivering reduced interface defects,suppressed non-radiative recombination and elongated charge carrier *** conversion efficiency(PCE)of 23.02%(0.04 cm^(2))and 21.6%(0.98 cm^(2),V_(OC) loss:0.336 V)have been achieved for the blade-coated PSCs(1.54 eV E_(g))with our new ETLs,representing a record for SnO_(2) based blade-coated ***,a substantially enhanced PCE(V_(OC))from 20.4%(1.15 V)to 22.8%(1.24 V,90 mV higher V_(OC),0.04 cm^(2) device)in the blade-coated 1.61 eV PSCs system,via replacing the benchmark commercial colloidal SnO_(2) with our new ETLs.

关键词： perovskite interface quantum

Optical to infrared mapping of vapor-to-liquid phase change dynamics using generative machine learning

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arXiv 2025年

作者： Khodakarami, Siavash Kabirzadeh, Pouya Wang, Chi Thukral, Tarandeep Singh Miljkovic, Nenad Department of Mechanical Science and Engineering University of Illinois at Urbana – Champaign UrbanaIL61801 United States Department of Electrical and Computer Engineering University of Illinois at Urbana – Champaign UrbanaIL61810 United States Material Research Laboratory University of Illinois at Urbana – Champaign UrbanaIL61801 United States Air Conditioning and Refrigeration Center University of Illinois at Urbana – Champaign UrbanaIL61801 United States University of Illinois UrbanaIL United States Kyushu University 744 Motooka Nishi-ku Fukuoka819-0395 Japan

Infrared thermography is a powerful tool for studying liquid-to-vapor phase change processes. However, its application has been limited in the study of vapor-to-liquid phase transitions due to the presence of complex liquid dynamics, multiple phases within the same field of view, and experimental difficulty. Here, we develop a calibration framework which is capable to studying one of the most complex two-phase heat transfer processes: dropwise condensation. The framework accounts for non-uniformities arising from dynamic two-phase interactions such as droplet nucleation, growth, coalescence, and departure, as well as substrate effects particularly observed on micro- and nanoengineered surfaces. This approach enables high-resolution temperature measurements with both spatial (12 µm) and temporal (5 ms) precision, leading to the discovery of local temperature phenomena unobservable using conventional approaches. These observed temperature variations are linked to droplet statistics, showing how different regions contribute to local condensation heat transfer. We extend the developed method to quantify local thermal parameters by fusing it with a generative machine learning model to map visual images into temperature fields. The model is informed of the physical parameter by incorporating vapor pressure embedding as the conditional parameter. This work represents a significant step toward simplifying local temperature measurements for vapor-to-liquid phase change phenomena by developing a methodology as well as a machine learning approach to map local thermal phenomena using only optical images as the input. © 2025, CC BY-NC-ND.

关键词： Thermography (temperature measurement)