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Reduced CoNi2S4 nanosheets decorated by sulfur vacancies with enhanced electrochemical performance for asymmetric supercapacitors

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Science China Materials 2020年第7期63卷 1216-1226页

作者： Yanpeng Liu Yuxiang Wen Yanan Zhang Xiaogang Wu Haoqian Li Hangda Chen Juanjuan Huang Guohan Liu Shanglong Peng National&Local Joint Engineering Laboratory for Optical Conversion Materials and Technology School of Physical Science and TechnologyLanzhou UniversityLanzhou 730000China Shenzhen Key Laboratory of Nanobiomechanics Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518055China Institute of Sensor Technology Gansu Academy of SciencesLanzhou 730000China

Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple *** these characteristics are usually related to the vacancies and impurities in the *** investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal *** the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other *** the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling *** with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great *** asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling *** feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.

关键词： defect engineering sulfur vacancies electrochemical performance asymmetric supercapacitors

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Competing effects of temperature and mechanical stress on polar vortex transition in oxide superlattices

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Physical Review B 2024年第19期110卷 195417-195417页

作者： Pan Chen Xu Hou Jiandi Zhang Congbing Tan Peng Gao Yan Liang Xuezeng Tian Lei Liao Xu-Sheng Yang Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China International Center for Quantum Materials and Electron Microscopy Laboratory School of Physics Peking University Beijing 100871 China Department of Industrial and Systems Engineering Research Institute for Advanced Manufacturing The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong China Department of Engineering Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Zheda Road 38 Hangzhou Zhejiang 310027 China The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518060 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and Electronics Hunan University of Science and Technology 411201 Hunan Xiangtan China

The interplay of different forms of energies in oxide superlattices, such as elastic, electrostatic, and gradient energies, can result in a stable long-range ordered polar vortex structure at room temperature. However, the role between these energies in determining the vortex structure still remains largely elusive due to the intricate interplay. By using a comprehensive in situ TEM apparatus and a prototype system, PbTiO3/SrTiO3 superlattice, we demonstrate that the vortex structure undergoes a first-order transition at the temperature around 653 K, while the application of in-plane mechanical stress at such a high temperature results in the reemergence of vortex structure. Cryogenic cooling to 94 K raises the stability of vortices, which would be destabilized by loading of out-of-plane mechanical stress. The results can be reproduced and well interpreted by phase-field simulations. These findings not only reveal the competing role of the temperature and mechanical stress at atomic scale but also demonstrate a feasible way to operate the vortex-based nanodevices working in harsh environments.

关键词： Electric polarization Ferroelectricity Electron diffraction Electron microscopy Liquid nitrogen cooling Phase-field modeling Scanning probe microscopy

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Highly efficient THz transient four-wave mixing in doped semiconductors

Highly efficient THz transient four-wave mixing in doped sem...

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International Conference on Infrared and Millimeter Waves

作者： N. Dessmann Nguyen H. Le V. Eless K. Saeedi S. G. Pavlov K. L. Litvinenko H. Riemann N. V. Abrosimov G. Aeppli B. Redlich B. Murdin Radboud University Institute for Molecules and Materials HFML-FELIX Nijmegen The Netherlands Advanced Technology Institute and Department of Physics University of Surrey Guildford UK Institute of Optical Sensor Systems German Aerospace Center (DLR) Berlin Germany Leibniz-Institut für Kristallzüchtung (IKZ) Berlin Germany Paul Scherrer Institute Villigen Switzerland

ISBN: (数字)9781728194271

ISBN: (纸本)9781728194288

We present a quantitative study of the efficiency of degenerate THz transient four-wave mixing in germanium doped by shallow impurities using the Dutch free electron laser FELIX. We derive the third order nonlinear sheet susceptibility and find values at low temperature that exceed those of any other material and wavelength range reported to date.

关键词： Temperature distribution Semiconductor lasers Four-wave mixing Impurities Free electron lasers Germanium Transient analysis

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Silver nanocolloid generation using dynamic Laser Ablation Synthesis in Solution system and drop-casting

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Nano-Structures and Nano-Objects 2022年 29卷

作者： McCarthy, Éanna Sreenilayam, Sithara Pavithran Ronan, Oskar Ayub, Hasan McCann, Ronan McKeon, Lorcan Fleischer, Karsten Nicolosi, Valeria Brabazon, Dermot I-Form Advanced Manufacturing Research Centre & Advanced Processing Technology Research Centre School of Mechanical and Manufacturing Engineering Dublin City University Glasnevin Dublin-9 Ireland I-Form and AMBER Research Centers School of Chemistry Trinity College Dublin Dublin 2 Ireland National Centre for Plasma Science and Technology Dublin City University Glasnevin Dublin 9 Ireland National Center for Sensor Research (NCSR) Dublin City University Glasnevin Dublin 9 Ireland

Conductive inks allow for low cost and scalable deposition of conductive tracks and patterns for printed electronics. Metal nanoparticle colloids are a novel form for producing conductive inks. Laser Ablation Synthesis in Solution (LASiS) is a “green” method for the production of metal nanoparticle colloids without the need for environmentally hazardous chemicals, however the method has typically been limited by its low production rates. This study reports on the generation of an additive free silver nanocolloid with maximized productivity using a flow-based LASiS system and its characterization using dynamic light scattering, UV–VIS, transmission electron microscopy and field emission scanning electron microscopy. The productivity of the LASiS silver nanoparticle (size ∼34 ± 5 nm) was ∼0.9 mg mL⁻¹. While the flow-based system achieves high laser ablation rates in the mass of nanomaterial generated per unit time, the volume of liquid required for the flow leads to relatively low concentrations. Therefore, in this work, LASiS concentrated ink was formulated via a centrifugal method, which was then drop-cast and heat treated to produce a conductive silver layer. Centrifuging to concentrate the ink was shown to be a necessary step to achieve good results, with the lowest resistance across the drop-cast material of 60.2 Ω after annealing. © 2022 Elsevier B.V.

关键词： Drop-casting TEM FESEM Laser ablation Nanocolloid Silver nanoparticle

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Optical Modelling Of Gaas/Gasb Core-Shell Cone Topped Octagonal Faced Nanopillar Array With Periodic Trapezoidal Textured Cut For High Photon Trapping Efficiency

Research Square

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Research Square 2021年

作者： Baruah, Smriti Borah, Janmoni Bora, Joyatri Maity, Santanu Department of Electronics and Communication Engineering Madanapalle Institute of Technology and Science Madanapalle India Department of Electronics and Communication Engineering North Eastern Regional Institute of Science and Technology Nirjuli India School of Advanced Materials Green Energy and Sensor Systems Indian Institute of Engineering Science and Technology Shibpur Howrah 711103 India

Proficiency in light reflectance mitigation is the most crucial factor for high photodetector *** this respect light trapping mechanism based on nanostructures or microstructures such as nanopillars,nanocones,nanopyramids have emerged as the most promising candidate for reducing overall light reflectance. This could be attributed to its effective large irradiation area, multiple scattering of incident light as well as increased path length of incident rays in these *** paper proposes an optical modelling of a GaAs/GaSb material based vertically oriented core-shell cone topped octagonal shaped nanopillar structure with periodical trapezoidal nanotexturization over it to be deployed over a circular planar detector’s surface of radius *** geometrical analytical investigation of the proposed model exhibits a 0.999 overall absorbance and 0.995A/W photoresponsivity along with 87% EQE at 1um operating wavelength. © 2021, CC BY.

关键词： Reflection

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Local structural study of α-MoO3 micro-strips using synchrotron X-ray diffraction and X-ray Absorption Spectroscopy at Mo K-edge

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EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS 2022年 97卷 65-65页

作者： Gawai, Umesh Kamble, Shilpa Kamble, Charudipa Waghmare, Yogita Kulkari, Suvarna Singh, Manvendra Yadav, Ashok Jha, Shambhu Dole, Babasaheb Department of Physics DDSP Arts Commerce and Science College Erandol Jalgaon 425109 (M.S.) India Department of Physics Shri Madhavrao Patil Mahavidyalaya Murum Osmanabad 413606 India Department of Physics and RUSA Centre for Advanced Sensor Technology Dr. Babasaheb Ambedkar Marathwada University Aurangabad 431004 (M.S.) India Department of Electronics K.R.T. Arts B.H. Commerce and A.M. Science College Nashik 422002 India Synchrotrons Utilization Section Raja Ramanna Centre for Advanced Technology Indore 452013 India Atomic & Molecular Physics Division Bhabha Atomic Research Centre Mumbai 400094 India Beamline Development & Application Section Bhabha Atomic Research Centre Mumbai 400094 India Advanced Materials Research Laboratory Department of Physics Dr. Babasaheb Ambedkar Marathwada University Aurangabad 431004 India

The orthorhombic MoO3 micro-strips sample was synthesized using microwave assisted chemical co-precipitation technique. Synchrotron X-ray Diffraction (SXRD) pattern and Rietveld Refinement was used to estimate structural parameter, crystallite size of sample. It reveals that the synthesized sample MoO3 crystallized as an orthorhombic phase. X-ray Absorption Spectroscopy (XAS) measurement, which comprises both X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) techniques, have been carried out on Mo K-edge to probe the local structure of samples. Local structure is also confirmed from the SXRD and Raman spectra of sample. XAS measurement reveals that the first bond length of Mo-O and Mo-Mo is 1.69 and 3.42 angstrom in orthorhombic MoO3 respectively. Transmission electron microscopy and SAED patterns showed stripe-like structure and single-crystal formation of MoO3 respectively.

关键词： Crystal structure

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A parallel Architecture of a Genetic Algorithm for EIT Image Reconstruction

A parallel Architecture of a Genetic Algorithm for EIT Image...

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IEEE SSD International Multi-Conference on Systems, Signals and Devices

作者： Mariem Hafsa Bilel Ben Atitallah Taha Ben Salah Najoua Essoukri Ben Amara Olfa Kanoun Professorship of Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany National Engineering School of Sousse University of Sousse Sousse Tunisia Université de Sousse Ecole Nationale d'Ingénieurs de Sousse LATIS-Laboratory of Advanced Technology and Intelligent Systems Sousse Tunisie

ISBN: (纸本)9781665414937;9781665430579

Nowadays, electrical impedance tomography (EIT) has become an interesting bio-medical imaging technique, it is non-invasive and shows great potential in medical investigation. The EIT presents high performances in conductivity mapping of the inner structure of a specific target. A set of electrodes are placed around the measured target where an excitation current is injected in a pre-defined frequency. This excitation will cause a variation of the potential distribution and consequently in the conductivity distribution of the measured medium. Therefore, boundary voltages are recorded, which will be used to provide the tomography image of the addressed cross-section. In this paper, the focus will be on the image reconstruction algorithm in order to reach high-quality images. A water tank set-up is used for the experiments where a conductive object is placed inside. Then, a genetic algorithm has been implemented in a parallel form to reduce the execution time by using a master/slave architecture. Moreover, to reach a high and accurate conductivity image, a reference technique has been integrated called the non-blind search. Further, a comparison study of genetic operators' configuration is carried out in terms of fitness values and object position identification. Nine combinations are tested, where the uniform crossover/random mutation shows the highest performance in object position identification with a fitness value equal to 0.0505. A comparison between the implemented solution and commonly used algorithms is established as well, where the genetic algorithm was able to outperform them in terms of fitness values.

关键词： Electric potential Current measurement Conductivity Genetics Storage tanks Frequency measurement Object recognition

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Forward Modelling of the Human Thorax for Electrical Impedance Tomography Measurements

Forward Modelling of the Human Thorax for Electrical Impedan...

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Impedance Spectroscopy (IWIS), International Workshop on

作者： Hamdi Haddad Oumaima Bader Mariem Hafsa Najoua Essoukri Ben Amara Olfa Kanoun University of Sousse National Engineering School of Sousse Sousse Tunisia LATIS- Laboratory of Advanced Technology and Intelligent Systems Université de Sousse Ecole Nationale d'Ingénieurs de Sousse Sousse Tunisie Professorship of Measurement and Sensor Technology Technische Universität Chemnitz Chemnitz Germany

Electrical Impedance Tomography (EIT) is a medical imaging technique that reflects the inner conductivity distribution of biological tissue based on boundary voltages measured at the electrodes around the thorax while injecting an alternating current with a low amplitude. In this work, a 16-electrode thorax mesh is implemented for the pyEIT library. This mesh builds the basis for the reconstruction of the conductivity distributions from real human thorax voltage measurements. Post-processing techniques, such as the K-means method and the region based segmentation, have also been implemented. The resulting re-constructed images reflect the conductivity changes during the breathing cycle and by post-processing artifacts are eliminated leading to a clear image of the lungs and the heart.

关键词： Heart Electrical impedance tomography Image segmentation Voltage measurement Impedance measurement Lung Conductivity

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Design and deployment of LoRaWAN smart streetlight for smart city

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AIP Conference Proceedings 2024年第1期2898卷

作者： Syed Muhammad Mamduh Syed Zakaria Ammar Zakaria Latifah Munirah Kamarudin Retnam Visvanathan Yuzairi Abdul Rahim Kamarulzaman Kamarudin Noraini Azmi Nurul Safirah Mohammad Faculty of Electronic Engineering Technology Universiti Malaysia Perlis Kampus Pauh Putra Perlis Malaysia Centre of Excellence for Advanced Sensor Technology (CEASTech) Arau Perlis Malaysia Faculty of Electrical Engineering Technology Universiti Malaysia Perlis Kampus Pauh Putra Perlis Malaysia Faculty of Mechanical Engineering Technology Universiti Malaysia Perlis Kampus Pauh Putra Perlis Malaysia

Streetlights are one of the major contributors of a city's energy usage, creating a large carbon footprint especially for highly populated areas. Current streetlights are turned on and off based on fixed schedule or by light sensors. Previous works have suggested the dimming of streetlights during zero traffic conditions to reduce energy consumption. This requires a reliable and economical communication backbone to ensure minimal service disruption. This work presents the design and performance evaluation of LoRa-based smart streetlight controllers in an urban environment. The deployment was designed to provide stress test, simulate communication connectivity, maintenance routine, firmware test and environmental conditions. The setup may also be used for staff training purposes and demonstration. The results of this work may be used achieve the effective control method for power saving, system stability, robustness and long-term performance. The deployed system includes test controllers, nodes, application server, database, gateway server and visualization dashboard. The system design demonstrated low packet error rates of approximately 1% and command response time of less than 3s in real world conditions.

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Effect of Hemoglobin Hydration on the Physical Properties of Erythrocyte Cytoplasm and Whole Blood

SSRN

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SSRN 2022年

作者： Zhbanov, Alexander Lee, Ye Sung Son, Minkook Jung, Myoung Hoon Eom, Kunsun Yang, Sung 123 Cheomdangwagi-ro Buk-gu Gwangju61005 Korea Republic of 123 Cheomdangwagi-ro Buk-gu Gwangju61005 Korea Republic of Healthcare Sensor Lab Device Research Center Samsung Advanced Institute of Technology Samsung Electronics Co. Ltd. 130 Samsung-ro Yeongtong-gu Suwon-si Gyeonggi-do 16678 Korea Republic of

Electrochemical impedance spectroscopy of whole blood and blood cells has great potential for assessing the health of patients. This potential has not been fully exploited for a detailed examination of the erythrocyte interior. The erythrocyte interior (cytoplasm) is often considered as continuous media. However, cytoplasm is a colloidal suspension of hydrated hemoglobin molecules. This study mainly focuses on the effect of hemoglobin hydration on the dielectric properties of erythrocyte cytoplasm and whole blood. The impedance spectra of separated cytoplasm and whole blood were measured at frequencies from 1 kHz to 110 MHz. The effective medium theory was used to analyze the experimental data. The cytoplasm was found to be best described as a colloid of hemoglobin cores surrounded by double hydration shells. The dielectric properties of the hemoglobin core, hydration shells and free intracellular fluid, as well as the thickness of the shells, were numerically determined from the impedance spectrum. An approach was developed to determine the intracellular fluid's viscosity and the density of bound water in the hydration shells. It shows that the hemoglobin hydration has a significant effect on the physical properties of blood. The detailed electrical properties of the cytoplasm can be detected from the impedance spectrum of whole blood. © 2022, The Authors. All rights reserved.

关键词： Hemoglobin

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