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arXiv 2023年

作者： Zhou, Xinyi Chao, Paul Sloan, Luke Lien, Huai-Hsun Hunter, Allen H. Misra, Amit Shahani, Ashwin J. Engineering Physics Program University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Michigan Center for Materials Characterization University of Michigan Ann ArborMI48109 United States Department of Chemical Engineering University of Michigan Ann ArborMI48109 United States

Al-Si alloys processed by laser rapid solidification yield eutectic microstructures with ultrafine and interconnected fibers. Such fibrous structures have long been thought to bear resemblance to those formed in impurity-doped alloys upon conventional casting. Here, we show that any similarity is purely superficial. By harnessing high-throughput characterization and computer vision techniques, we perform a three-dimensional analysis of the branching behavior of the ultrafine eutectic and compare it against an impurity-modified eutectic as well as a random fractal (as a benchmark). Differences in the branching statistics point to different microstructural origins of the impurity- and quench-modified eutectic. Our quantitative approach is not limited to the data presented here but can be used to extract abstract information from other volumetric datasets, without customization. © 2023, CC BY.

关键词： Eutectics

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High pressure synthesis and characterization of the pyrochlore Dy2Pt2O7:A new spin ice material

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Chinese physics B 2020年第4期29卷 116-120页

作者： Qi Cui Yun-Qi Cai Xiang Li Zhi-Ling Dun Pei-Jie Sun Jian-Shi Zhou Hai-Dong Zhou Jin-Guang Cheng Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Materials Science and Engineering Program Mechanical EngineeringUniversity of Texas at AustinAustinTexas 78712USA Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement of Ministry of Education School of PhysicsBeijing Institute of TechnologyBeijing 100081China Department of Physics and Astronomy University of TennesseeKnoxvilleTN 37996USA School of Physics Georgia Institute of TechnologyAtlantaGA 30332USA Songshan Lake Materials Laboratory Dongguan 523808China

The cubic pyrochlore Dy2Pt2O7 was synthesized under 4 GPa and 1000℃ and its magnetic and thermodynamic properties were characterized by DC and AC magnetic susceptibility and specific heat down to 0.1 *** found that Dy2Pt2O7 does not form long-range magnetic order,but displays characteristics of canonical spin ice such as Dy2Pt2O7,including(1)a large effective moment 9.64μB close to the theoretical value and a small positive Curie-Weiss temperatureθCW=+0.77 K signaling a dominant ferromagnetic interaction among the Ising spins;(2)a saturation moment ~4.5μB being half of the total moment due to the local<111>Ising anisotropy;(3)thermally activated spin relaxation behaviors in the low(~1 K)and high(~20 K)temperature regions with different energy barriers and characteristic relaxation time;and most importantly,(4)the presence of a residual entropy close to Pauling’s estimation for water ice.

关键词： Dy2Pt2O7 pyrochlore oxide spin ice high-pressure synthesis

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Unavoidable emergent biaxiality in chiral molecular-colloidal hybrid liquid crystals

arXiv

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arXiv 2023年

作者： Wu, Jin-Sheng Lázaro, Marina Torres Ghosh, Souvik Mundoor, Haridas Wensink, Henricus H. Smalyukh, Ivan I. Department of Physics and Chemical Physics Program University of Colorado BoulderCO United States Laboratoire de Physique des Solides UMR 8502 Université Paris-Saclay CNRS Orsay91405 France International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima Japan Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado BoulderCO United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

Chiral nematic or cholesteric liquid crystals (LCs) are chiral mesophases with long-ranged orientational order featuring a quasi-layered periodicity imparted by a helical director configuration but lacking positional order. Doping molecular cholesteric LCs with thin colloidal rods with a large length-to-width ratio or disks with a large diameter-to-thickness ratio adds another level of complexity to the system because of the interplay between weak surface anchoring boundary conditions and bulk-based elastic distortions around the particle-LC interface. By using colloidal disks and rods with different geometric shapes and boundary conditions, we demonstrate that these anisotropic colloidal inclusions exhibit biaxial orientational probability distributions, where they have tendencies to orient with the long rod axes and disk normals perpendicular to the helix axis, thus imparting strong local biaxiality on the hybrid cholesteric LC structure. Unlike the situation in non-chiral hybrid molecular-colloidal LCs, where biaxial order emerges only at modest to high volume fractions of the anisotropic colloidal particles, above a uniaxial-biaxial transition concentration, the orientational probability distribution of colloidal inclusions immersed in chiral nematic hosts are unavoidably biaxial even at vanishingly low particle volume fractions. In addition, the colloidal inclusions induce local biaxiality in the molecular orientational order of the LC host medium, which enhances the weak biaxiality of the LC in a chiral nematic phase coming from the symmetry breaking caused by the presence of the helical axis. With the help of analytical modeling and computer simulations based on minimizing the Landau de Gennes free energy of the host LC around the colloidal inclusions, we explain our experimental findings and conclude that the biaxial order of chiral molecular-colloidal LCs is strongly enhanced as compared to both achiral molecular-colloidal LCs and molecular cholesteric LCs

关键词： Probability distributions

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Stress-shape misalignment in confluent cell layers

arXiv

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arXiv 2023年

作者： Nejad, Mehrana R. Ruske, Liam J. McCord, Molly Zhang, Jun Zhang, Guanming Notbohm, Jacob Yeomans, Julia M. The Rudolf Peierls Centre for Theoretical Physics Department of Physics University of Oxford Parks Road OxfordOX1 3PU United Kingdom Biophysics Program University of Wisconsin-Madison United States Department of Mechanical Engineering University of Wisconsin-Madison United States Department of Engineering Physics University of Wisconsin-Madison United States Center for Soft Matter Research Department of Physics New York University New York10003 United States Simons Center for Computational Physical Chemistry Department of Chemistry New York University New York10003 United States

This study investigates the relationship between cell shape and cell-generated stresses in confluent cell layers. Using simultaneous measurements of cell shape orientation and cell-generated contractile forces in MDCK and LP-9 colonies, we report the emergence of correlated, dynamic domains in which misalignment between the directors defined by cell shape and by contractile forces reaches up to 90o, effectively creating extensile domains in a monolayer of contractile cells. To understand this misalignment, we develop a continuum model that decouples the orientation of cell-generated active forces from the orientation of the cell shapes. This challenges the prevailing understanding that cells throughout a tissue create either contractile or extensile forces, and the validity of the usual active nematic models of cell motility where active forces are strictly slaved to cell shape orientation. © 2023, CC BY.

关键词： Cells

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Imbalance fault detection in BLDC motors through audio signals using the density of maxima and CNN

Imbalance fault detection in BLDC motors through audio signa...

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Brazilian Symposium on Computing System engineering (SBESC)

作者： Yuri C. Gouveia Alisson V. Brito Tiago P. Nascimento Jorge Gabriel Ramos Abel Lima Filho Graduate Program in Informatics Universidade Federal da Paraiba Joao Pessoa Brazil Laboratory of System Engineering and Robotics Universidade Federal da Paraiba Joao Pessoa Brazil Department of Physics Universidade Federal da Paraiba Joao Pessoa Brazil Department of Mechanical Engineering Universidade Federal da Paraiba Joao Pessoa Brazil

Unmanned Aerial Vehicles (UAVs), commonly known as drones, are increasingly used for various tasks. However, increased usage leads to more failures, posing risks to humans and the environment. This study identifies propeller imbalance faults in Brushless DC (BLDC) motors of UAVs. It compares two fault detection methodologies based on chaotic behavior: the alreadyknown CNN approach, and the SAC-DM+CNN approach. Both methods involve acquiring audio signals, generating spectrograms, and training a Convolutional Neural Network (CNN) model. Results show that the CNN approach achieves 98.18% accuracy, while the SAC-DM+CNN approach achieves 71.43% accuracy in classifying propeller balance faults.

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Frequency-Dependent Dielectric Characterization of Bi1.75pb0.25sr2ca2cu3-Xsnxo10+Δ Glass Ceramics System

SSRN

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SSRN 2023年

作者： Kaya, Naki Bariş, Çağrı Öcal Çavdar, Şükrü Tuğluoğlu, Nihat Koralay, Haluk Seçkin, Ayten Kafkas University Kağızman Vocational School Department of Medical Service Optician Program Kars Turkey Gazi University Ankara Turkey Garching bei MünchenD-85748 Germany Department of Physics Gazi University Ankara06531 Turkey Giresun University Faculty of Engineering Department of Energy Systems Engineering Giresun Turkey

In this study, Bi1.75Pb0.25Sr2Ca2Cu3-xSnxO10+δ glass ceramic structure;(x = 0.0, 0.3, 0.5) depending on Cu3-x-Snx displacement, frequency-dependent (100 Hz-2 MHz), capacitance-conductance measurements were taken at 75 K and 125 K temperature values. Dielectric constant reel part (Ε'), imaginary dielectric constant (Ε''), dielectric loss (tanδ) and ac electrical conductivity (σac) frequency dependence were analyzed using the capacitance–voltage (C–V) and conductance-voltage (G-V) measurements. Sn doping had a negative capacitive effect and a decrease in capacitive effect was observed with the addition of Sn doping rate. The observed negative capacitance effect is believed to arise from the polarization effect generated by the Sn dopant. The negative dielectric constant and the virtual negative dielectric constant were calculated from the negative capacitance values. While the undoped sample exhibits a positive capacitance characteristic, the addition of Sn dopant to the samples results in the observation of a negative capacitance property. © 2023, The Authors. All rights reserved.

关键词： Capacitance

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The Utilization of Padding Scheme on Convolutional Neural Network for Cervical Cell Images Classification

The Utilization of Padding Scheme on Convolutional Neural Ne...

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2020 International Conference on Computer engineering, Network, and Intelligent Multimedia, CENIM 2020

作者： Haryanto, Toto Sitanggang, Imas Sukaesih Agmalaro, Muhammad Ashyar Rulaningtyas, Riries IPB University Computer Science Department Bogor Indonesia Universitas Airlangga Biomedical Engineering Program Department of Physics Surabaya Indonesia

ISBN: (纸本)9781728182834

Cervical cancer identification through pap-smear images analysis is a challenge for medicians, especially in distinguishing cells, between the normal and abnormal one. This study aims to create the classification model of Cervical Cell Images using the Convolutional Neural Network (CNN) algorithm. The dataset used is the image dataset SIPaKMeD. The CNN algorithm was implemented using the AlexNet architecture with and non-padding scheme. Padding is included in the experiments by adding the pixel 0 on the original images to improve the accuracy of the model. The experimental results show that using the utilization padding scheme on the AlexNet architecture can increase the accuracy of the model slightly significantly from 84.88% to 87.32%. © 2020 IEEE.

关键词： Convolutional neural networks

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Phase-engineered heterostructures of Mo2C by plasma-assisted selenization and sulfurization processes toward excellent hydrogen evolution reaction

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Nano Energy 2024年 122卷

作者： Kimbulapitiya, K.M.M.D.K. Rehman, Bushra Wani, Sumayah Shakil Chen, Chieh-Ting Cyu, Ruei-Hong Manikandan, Arumugam Date, Manisha Kondiba Peng, Yu-Ren Kumara, R.J.G.L.R. Chuang, Feng-Chuan Chueh, Yu-Lun Department of Physics National Sun Yat-sen University Kaohsiung80424 Taiwan Department of Materials Science and Engineering National Tsing-Hua University Hsinchu Taiwan College of Semiconductor Research National Tsing-Hua University Hsinchu30013 Taiwan Center for Nanotechnology Materials Science and Microsystem National Tsing-Hua University Hsinchu Taiwan Ph.D. Program in Prospective Functional Materials Industry National Tsing Hua University Hsinchu30013 Taiwan Physics Division National Center for Theoretical Sciences Hsinchu30013 Taiwan Center for Theoretical and Computational Physics National Sun Yat-Sen University Kaohsiung80424 Taiwan Department of Physics National Tsing Hua University Hsinchu30013 Taiwan

Due to the outstanding semiconducting and metallic properties, 2D materials such as Transition Metal dichalcogenides (TMDs) and Transition Metal Carbides (TMCs) appear to be promising candidate for Nano-scale electronics devices. Among them, 2D - Mo2C (Molybdenum carbide) has attracted attention as a new member of the MXene group, owing to its potential applications for superconductors, electronics devices, and catalysts for Hydrogen evolution Reactions (HER). Structural modification toward the creation of novel heterostructures with phase engineering opens new pathways for different applications. Herein, we prepared a large area Mo2C film by chemical vapor deposition method. The upper region of Mo2C layers can be oxidized to create Mo2C/MoOx heterostructures. Furthermore, those oxide layers were further transformed into MoSe2 and MoS2 by plasma-assisted selenization and sulfurization processes at different temperatures with a fixed plasma power of 150 W. The heterostructures demonstrated outstanding electrocatalytic activity for HER due to an existed metallic phase and active sites present after plasma-assisted selenization and sulfurization processes at the low temperature. The performance of the HER decreases at high temperatures owing to their semiconducting phase. The pristine Mo2C showed a Tafel slope of 72 mV dec−1 and an overpotential of 276 mV at 10 mA/cm2, while the Mo2C/MoSe2 heterostructure synthesized at 350 °C350 °exhibited an improved Tafel slope of 66 mV dec−1 and overpotential of 257 mV at 10 mA/ cm2. Additionally, the Mo2C/MoS2 heterostructure prepared at 350 °C also demonstrated a 263 mV improvement in overpotential at 10 mA/cm2. All the heterostructures showed excellent stability over a period of 10 h except Mo2C/MoOx. This work opens new strategies to fabricate high-quality MXene and TMDs heterostructures with metal-semiconductor interface. © 2024

关键词： Molybdenum compounds

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Implementation of Electromagnetic Measurements with Satellite Data for TLEs Determination and Classification

Implementation of Electromagnetic Measurements with Satellit...

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International Symposium on Lightning Protection (XII SIPDA)

作者： Carlos Gómez Fernando Díaz Francisco Román Torsten Neubert Víctor Reglero Nikolai Østgaard Electric Engineering Departament Universidad Nacional de Colombia Bogotá Colombia Electronic Engineering Program Universidad de Cundinamarca Fusagasugá Colombia National Space Institute Technical University of Denmark Kongens Lyngby Denmark Image Processing Laboratory University of Valencia Valencia Spain Department of Physics and Technology University of Bergen Bergen Norway

This paper describes a lightning measurement station together with preliminary results of using both electric and magnetic field records in conjunction with satellite data provided by ASIM project to establish the presence of Transient Luminous Events in images captured by satellite platforms. The lightning measurement station is located near the center of Colombia at an altitude of 3,000 m.a.s.l.

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Enhancing Zinc Electrode Stability Through Pre-Desolvation and Accelerated Charge Transfer Via a Polyimide Interface

SSRN

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SSRN 2023年

作者： Lai, Chi-Yu Liao, Yin-Song Ku, Hao-Yu Jao, Wen-Yang Gull, Sanna Chen, Han-Yi Chou, Jyh-Pin Hu, Chi-Chang Department of Chemical Engineering National Tsing Hua University Hsinchu300044 Taiwan Tsing Hua Interdisciplinary Program National Tsing Hua University Hsinchu300044 Taiwan Department of Materials Science and Engineering National Tsing Hua University Hsinchu300044 Taiwan Department of Physics National Changhua University of Education Changhua50074 Taiwan

Aqueous zinc-based energy storage devices possess superior safety, cost-effectiveness, and high energy density;however, dendritic growth and side reactions on the zinc electrode curtail their widespread applications. In this study, we mitigate these issues by introducing a polyimide (PI) nanofabric interfacial layer onto the zinc substrate. Simulations reveal that the PI nanofabric promotes a pre-desolvation process, effectively desolvating hydrated zinc ions from Zn(H2O)62+ to Zn(H2O)42+ before approaching zinc surface. The exposed zinc ion in Zn(H2O)42+ provides an accelerated charge transfer process and reduces the activation energy for zinc deposition from 40 to 21 kJ mol−1. The PI nanofabric also acts as a protective barrier, reducing water molecule interactions and side reactions at the electrode. The PI-Zn symmetric cell exhibits remarkable cycling stability over 1200 h, maintaining a dendrite-free morphology and minimal byproduct formation. Moreover, the cell exhibits high stability and low voltage hysteresis even under high current densities (20 mA cm−2, 10 mAh cm−2) thanks to the three-dimensional porous structure of PI nanofabric. When integrated into full cells, the PI-Zn||AC hybrid zinc-ion capacitor and PI-Zn||MnVOH@SWCNT zinc-ion battery achieve impressive lifespans of 15000 and 600 cycles with outstanding capacitance retention. This approach paves a novel avenue for high-performance zinc metal electrodes. © 2023, The Authors. All rights reserved.

关键词： Charge transfer

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