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Using 4D-STEM to Map 3D Morphologies of 2D materials

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 262-263页

作者： Mireles, Adan Shi, Chuqiao Park, Jeongwon Shin, Bongki Sung, Suk Hyun Ophus, Colin Hovden, Robert Kang, Kibum Han, Yimo Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX United States Department of Materials Science and NanoEngineering Rice University Houston TX United States Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Materials Science and Engineering University of Michigan Ann Arbor MI United States National Center for Electron Microscopy Molecular Foundry Lawrence Berkeley National Laboratory Berkeley CA United States

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Correlating the Ambient Conditions and Performance Indicators of the LoRaWAN via Surrogate Gaussian Process-Based Bidirectional LSTM Stacked Autoencoder

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IEEE Transactions on Network and Service Management 2023年第3期20卷 3413-3427页

作者： Bhat, Showkat Ahmad Huang, Nen-Fu Hussain, Imtiyaz Sajjad, Uzair National Tsing Hua University College of Electrical and Computer Science Hsinchu1300044 Taiwan National Tsing Hua University Department of Computer Science Hsinchu1300044 Taiwan National Taipei University of Technology Graduate Program in Energy and Opto-Electronic Materials Taipei10608 Taiwan National Taipei University of Technology Department of Energy and Refrigerating Airconditioning Engineering Taipei10608 Taiwan

LoRa's biggest advantage is its flexibility, which is the ability to increase or decrease data rate and range while decreasing or increasing sensitivity. Whenever propagation conditions change frequently, this function allows the spreading factor to be modified accordingly. Despite their efficiency and scalability, adaptive data rate algorithms ignore and fail to factor in the complex correlation between ambient weather parameters influencing the communication channel design. In this research, a Bayesian surrogate Gaussian process-based bidirectional LSTM stacked autoencoder model (BSGP-BLSTM-SAE) is proposed to estimate the channel performance indicators such as received signal strength indicator (RSSI) and signal-to-noise ratio (SNR) and to determine the correlation between the ambient weather conditions and performance indicators for the LoRaWAN network. Bayesian optimization algorithm has been used to optimize the hyper-parameters of the developed model. A LoRaWAN experimental multivariate time series dataset has been used for the evaluation of the developed model, which upon testing and validation produces high accuracy in predicting the channel performance indicators and ambient conditions of the experimental LoRaWAN network. The mean absolute error of the developed model was around 0.45. Thus, the proposed model can predict the link performance indicators and thereby assist in real-time optimization of the transmission parameters to enhance the network performance in LoRaWAN-based systems at different ambient conditions. © 2004-2012 IEEE.

关键词： Internet of things

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New insights into the hardening and pitting corrosion mechanisms of thermally aged duplex stainless steel at 475℃:A comparative study between 2205 and 2101 steels

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Journal of materials science & Technology 2022年第3期98卷 123-135页

作者： R.Silva G.S.Vacchi C.L.Kugelmeier I.G.R.Santos A.A.Mendes Filho D.C.C.Magalhães C.R.M.Afonso V.L.Sordi C.A.D.Rovere Munir Rachid Corrosion Laboratory Department of Materials EngineeringFederal University of São CarlosRodovia Washington Luis Km 23513565-905 São CarlosSPBrazil Engineering Modeling and Applied Social Sciences Center(CECS)Federal University of ABCAvenida dos Estados 500109210580 Santo AndréSPBrazil Federal University of São Carlos Graduate Program in Materials Science and EngineeringBrazil

In this study,the relationship between spinodal decomposition and the formation of Ni-rich clusters and G-phase in the ferrite on hardening and pitting corrosion of two thermally aged duplex stainless steels(DSSs)at 475℃was *** indicate that,for 2205 DSS,pitting corrosion behavior is influenced by the presence and size of G-phase precipitates for longer aging times,but this contribution is masked by the advanced stage of spinodal decomposition in the ferritic *** the other hand,for 2101 DSS,the formation of Cr-richer nitrides impairs pitting corrosion resistance more than spinodal decomposition.

关键词： Duplex stainless steel Spinodal decomposition G-phase precipitation Pitting corrosion Hardening

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Characterizations of Ni-loaded lignite char catalysts and their performance enhancements to catalytic steam gasification of coal

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Journal of the Energy Institute 2022年 105卷 53-71页

作者： Tipo, Ronnachai Tippayawong, Nakorn Chaichana, Chatchawan Chimupala, Yothin Chaiklangmuang, Suparin Graduate Program in Industrial Chemistry Faculty of Science Chiang Mai University Chiang Mai50200 Thailand Department of Industrial Chemistry Faculty of Science Chiang Mai University Chiang Mai50200 Thailand Department of Mechanical Engineering Faculty of Engineering Chiang Mai University Chiang50200 Thailand Center of Excellence in Materials Science and Technology Faculty of Science Chiang Mai University Chiang Mai50200 Thailand Materials Science Research Center Faculty of Science Chiang Mai University Chiang Mai50200 Thailand

Catalyst characteristics such as specific surface area, porosity and active site play an essential role in catalyst design. Understanding of the characteristic functions in controlling catalyst activity is necessary for considering the catalyst application, especially the Ni-loaded lignite char catalyst, employed in catalytic steam gasification. In this work, the unmodified and five modified catalysts were used to study the effect of catalyst characteristics on their performance for catalytic steam gasification of coal in the two-stage fixed-bed reactor. The findings indicated that the fresh acid modified catalysts increased specific surface area and micropore formation, including the smaller Ni metal crystallite size, the decreasing of Ni metal nanoparticle size and the well-dispersed of Ni metal nanoparticles. Meanwhile, the fresh modified catalysts by the alkali and the combined alkali-acid treatments promoted mesopore formation. Enhancing catalytic steam gasification of coal, it was found that the mesoporosity of catalyst was the considerable initial characteristic for controlling the catalyst activity. The total gas yields of the mesoporous catalysts were in the range of 50.65–77.70 mmol/gVM,feed, while the total gas yields of the microporous catalysts were 43.82–55.34 mmol/gVM,feed. After catalyst testings, the specific surface areas and number of mesopores in the spent catalysts were increased by steam. Remarkably, these changing pore sizes affected the transformations of the isotherms (type I + II to type II) and the hysteresis loops (type H4 to type H3). Also, steam influenced the conversion of Ni metals to NiO, Ni(OH)2 and Ni2O3. For thermal property, all spent catalysts had high thermal stability. The modified catalysts could decrease carbon deposition more than the unmodified catalyst, which was an upside for catalyst reusability. © 2022 Energy Institute

关键词： Catalyst activity

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Elevated temperature-driven coordinative reconstruction of an unsaturated single-Ni-atom structure with low valency on a polymer-derived matrix for the electrolytic oxygen evolution reaction

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Nanoscale 2024年第15期16卷 7467-7479页

作者： Patil, Rahul Rajput, Anubha Matsagar, Babasaheb M. Chen, Norman C. R. Ujihara, Masaki Salunkhe, Rahul R. Yadav, Praveen Wu, Kevin C.-W. Chakraborty, Biswarup Dutta, Saikat Electrochemical Energy & Sensor Research Laboratory Amity Institute of Click Chemistry Research & Studies Amity University Noida India Department of Chemistry Indian Institute of Technology New Delhi India Department of Chemical Engineering National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taiwan National Taiwan University Taiwan Graduate Institute of Applied Science and Technology National Taiwan University of Science and Technology Taipei Taiwan Materials Research Laboratory Department of Physics Indian Institute of Technology Jammu India Synchrotron X-ray Facility Raja Ramanna Centre for Advanced Technology Rajendra Nagar Madhya Pradesh 452013 Indore India

A high-temperature pyrolysis-controlled coordination reconstruction resulted in a single-Ni-atom structure with a Ni-Nx-C structural unit (x = N atom coordinated to Ni). Pyrolysis of Ni-phen@ZIF-8-RF at 700 °C resulted in NiNP-NC-700 with predominantly Ni nanoparticles. Upon elevating the pyrolysis temperature from 700 to 900 °C, a coordination reconstruction offers Ni-Nx atomic sites in NiSA-NC-900. A combined investigation with X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and soft X-ray L3-edge spectroscopy suggests the stabilization of low-valent Niδ+ (0 −2 was achieved. The cell potential recorded with Pt(−)/(+)NiSA-NC-900/NF was much lower than that obtained for other cells, i.e., Pt(−)/NF and NF(−)/(+)NF, which enhances the potentials of low-valent NiSAs for insightful understanding of the OER. At a constant applied potential of 1.61 V (vs. RHE) for 12 h, an small increase in current for initial 0.6 h followed by a constant current depicts the fair stability of catalyst for 12 h. Our results offer an insightful angle into the OER with a coordinatively reconstructed single-Ni-atom structure at lower valency ( © 2024 The Royal Society of Chemistry.

关键词： Reaction kinetics

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Vibrational entropies of oxygen vacancy formation in metal oxides

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Physical Review materials 2024年第5期8卷 055407-055407页

作者： Bianca Baldassarri Jiangang He Christopher Wolverton Graduate Program in Applied Physics Northwestern University Evanston Illinois 60208 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA

Oxygen vacancies play a key role in many energy-related applications, and the investigation of the thermodynamic forces driving their formation across different materials can be tackled through the use of ab initio methods. In this context, however, computational studies targeting finite-temperature properties such as entropy remain scarce. Wider-ranging studies are of interest to deepen the understanding of the role of the entropy of oxygen vacancy formation and its different components in processes like the ones involved in solar thermochemical hydrogen (STCH) production, and to investigate the existence of common trends and differences between materials. In this work, we use density functional theory and harmonic phonon calculations to compute the vibrational entropy of oxygen vacancy formation (ΔSvib) for 10 different metal oxide compounds. The computation is carried out by taking the difference between the vibrational entropy of a vacancy-containing and a pristine structure, while the entropic contribution from the final gaseous state of the oxygen lost from the material is accounted for separately with a gas entropy term. We first examine the temperature dependence of ΔSvib and highlight the presence of an initial peak around room temperature, followed by a steady decrease resulting from the presence of an additional O atom (the one becoming vacant) in the defect-free structure. We then inspect the atomic contributions to ΔSvib, and highlight similarities and differences between compounds. Finally, we consider other significant sources of entropy, and find ΔSvib to provide a smaller, yet non-negligible, contribution to the total entropy of vacancy formation. We also compare the temperature dependence of ΔSvib to that of the gas entropy, and show that the two largely counterbalance each other at high temperatures.

关键词： Entropy Hydrogen production Density functional theory

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Preparation of LFP-based cathode materials for lithium-ion battery applications

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materials Today: Proceedings 2022年 65卷 2347-2350页

作者： Suttison, Suchanat Pengpat, Kamonpan Intatha, Uraiwan Fan, Jinchen Zhang, Wei Eitssayeam, Sukum Master's Degree Program in Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Graduate School Chiang Mai University Chiang Mai Thailand Department of Physics and Materials Science Faculty of Science Chiang Mai University Thailand Center of Innovative Materials for Sustainability School of Science Mae Fah Luang University Chiang Rai 57100 Thailand School of Materials and Chemistry University of Shanghai for Science and Technology Shanghai 200093 China Department of Engineering Mechanics Dalian University of Technology Dalian 116024 China

Lithium-ion batteries (LIB) have developed into the mainstream power source of energy storage devices due to their advantages: high power density, high power, long service life, and less pollution. This materials development for LFP batteries was considered successful in synthesizing powder. Here we show that three synthesis conditions were performed. LFP doped NiO, NMC, and (NH4)2HPO4 were synthesized by the nitrogen gas flow method. LFP-doped NiO was burned at 600 °C and 700 °C for five h. NMC doped with LFP burned at 550 °C for five h, and NMC-doped LFP and (NH4)2HPO4 were burned at 550 °C and 600 °C for five h. The structure and morphology of the material were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). © 2022

关键词： Lithium-ion batteries

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Evaluation of the Influence of Eggshell (ES) Concentration on the Degradation Behavior of Mg-2.5Zn Biodegradable Alloy in Simulated Body Fluid

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ACS Biomaterials science and engineering 2023年第5期9卷 2376-2391页

作者： Radwan, A. Bahgat Okonkwo, Paul C. Murugan, Srinivasan Parande, Gururaj Taryba, Maryna Montemor, M. Fatima Al-Mansoori, Layla Elrayess, Mohamed A. Al-Qahtani, Noora Gupta, Manoj Youssef, Khaled M. Case, Raymundo Shakoor, R.A. Abdullah, Aboubakr M. Center for Advanced Materials Qatar University Doha2713 Qatar Department of Mechanical and Mechatronics Engineering Dhofar University Salalah211 Oman Mahendra Engineering College Tamil Nadu Namakkal637503 India Department of Mechanical Engineering National University of Singapore 9 Engineering Drive 1 Singapore117576 Singapore Centro de Quimica Estrutural Instituto Superior Técnico Universidade de Lisboa Avenida Rovisco Pais Lisboa1049-001 Portugal Qatar University Doha2713 Qatar Materials Science and Technology Graduate Program College of Arts and Sciences Qatar University Doha2713 Qatar Department of Materials Science and Engineering Texas A&M University College StationTX77843 United States

Currently, permanent vascular stents are fabricated using titanium and stainless steel implants that are nondegradable and offer high stability, but they have certain disadvantages. For example, the prolonged exposition of aggressive ions in the physiological media and the existence of defects in the oxide film create conditions for corrosion to occur, thus triggering unwanted biological events and compromising the mechanical integrity of the implants. Moreover, when the implant does not need to be permanent, there is the need to submit the patient for a second surgery for implant removal. As a solution for nonpermanent implants, biodegradable magnesium alloys have been deemed a promising substitute, for example, for cardiovascular-related applications and the construction of orthopedic devices. A biodegradable magnesium alloy (Mg-2.5Zn) reinforced by zinc and eggshell was employed in this study as an environment-conscious magnesium (eco) composite (Mg-2.5Zn-xES). Disintegrated melt deposition (DMD) was used to fabricate the composite. Experimental studies were conducted to investigate the biodegradation performance of Mg-Zn alloys containing 3 and 7 wt % eggshell (ES) in simulated body fluid (SBF) at 37 °C. Different corrosion techniques were used to study the corrosion behavior of the Mg-2.5Zn-xES composites, including weight loss measurements, hydrogen evolution, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning vibrating electrode technique (SVET). Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were employed to scrutinize the corroded surfaces’ morphology and composition. The outcomes indicated that Mg-2.5Zn-3ES possesses the lowest degradation activity. © 2023 American Chemical Society.

关键词： Electrochemical impedance spectroscopy

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Recent advances in electronic devices for monitoring and modulation of brain

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Nano Research 2021年第9期14卷 3070-3095页

作者： Yong Won Kwon Yoon Sun Jun Young-Geun Park Jiuk Jang Jang-Ung Park Nano Science Technology Institute Department of Materials Science and EngineeringYonsei UniversitySeoul 03722Republic of Korea Center for Nanomedicine Institute for Basic Science(IBS)Seoul 03722Republic of Korea Graduate Program of Nano Biomedical Engineering(NanoBME) Advanced Science InstituteYonsei UniversitySeoul 03722Republic of Korea

The brain is actuated by billions of neurons with trillions of interconnections that regulate human *** the mechanisms of these systems that induce sensory reactions and respond to disease remains one of the greatest challenges in science,engineering,and *** advances in nanomaterials and nanotechnologies have led to the extensive research of electronic devices for brain interfaces to better understand the neural activities of the brains complex nervous *** development of sensor devices for monitoring the physiological signals of the brain related to traumatic injury status has accompanied by the progress of electronic neural probes in *** addition,these neurological and stereotactic surgical revolutions hold immense potential for clinical analysis of pharmacological systems within cerebral ***,we review the progress of electronic devices interfacing with brain in terms of the materials,fabrication technologies,and device *** activity can be measured and modulated by brain probes based on newly developed nanofabrication ***,in vivo pathological monitoring of the brain and pharmacological assessment has been developed in miniaturized and wireless *** also consider the key challenges and prospects for further development,and explore the future directions emerging in the latest research.

关键词： neural interfaces neural recording neuromodulation intracranial pressure monitoring microfluidic drug delivery

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engineering dimensionality of collective dipole-dipole interactions using a nanophotonic environment

Engineering dimensionality of collective dipole-dipole inter...

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Boddeti, Ashwin K. Wang, Yi Juarez, Xitlali Boltasseva, Alexandra Alaeian, Hadiseh Odom, Teri W. Jacob, Zubin Elmore Family School of Electrical and Computer Engineering Birck Nanotechnology Center Purdue University West LafayetteIN47907 United States Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States

ISBN: (纸本)9781957171258

We experimentally demonstrate reduced dimensionality in a interacting ensemble of emitters. The well-known stretched exponential decay dynamics, (Equation presented) with β = 0.5 in 3D geometries, is strikingly modified in a nanophotonic environment that supports long-range interaction to β ~ 0.3. © Optica Publishing Group 2023.

关键词： Nanophotonics

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