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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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From isolated polyelectrolytes to star-like assemblies: The role of sequence heterogeneity on the statistical structure of the intrinsically disordered Neurofilament-low tail domain

arXiv

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arXiv 2023年

作者： Kravikass, Mathar Koren, Gil Saleh, Omar A. Beck, Roy School of Physics and Astronomy The center for Nanoscience and Nanotechnology The center of Physics and Chemistry of Living Systems Tel Aviv University Tel Aviv Israel Materials Department Biomolecular Sciences and Engineering Program Physics Department University of California Santa Barbara United States

Intrinsically disordered proteins (IDPs) are a subset of proteins that lack stable secondary structure. Given their polymeric nature, previous mean-field approximations have been used to describe the statistical structure of IDPs. However, the amino-acid sequence heterogeneity and complex intermolecular interaction network have significantly impeded the ability to get proper approximations. One such case is the intrinsically disordered tail domain of Neurofilament low (NFLt), which comprises a 50 residue-long uncharged domain followed by a 96 residue-long negatively charged domain. Here, we measure two NFLt variants to identify the impact of the NFLt two main subdomains on its complex interactions and statistical structure. Using synchrotron small-angle x-ray scattering, we find that the uncharged domain of the NFLt induces attractive interactions that cause it to self-assemble into star-like polymer brushes. On the other hand, when the uncharged domain is truncated, the remaining charged N-terminal domains remain isolated in solution with typical polyelectrolyte characteristics. We further discuss how competing long- and short-ranged interactions within the polymer brushes dominate their ensemble structure, and, in turn, their implications on previously observed phenomena in NFL native and diseased states. © 2023, CC BY.

关键词： X ray scattering

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Ytterbium Femtosecond Fiber Laser Ablation Synthesis of Silicon Nanocrystals in Water: Laser Frequency and Pulse Energy Dependence

SSRN

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SSRN 2023年

作者： Piatkowski, Piotr A. Ali, Asghar Ialyshev, Vadim Iqbal, Mazhar Alnaser, Ali S. Department of Physics American University of Sharjah Materials Science and Engineering Program College of Arts and Sciences PO Box 26666 Sharjah United Arab Emirates

The utilization of femtosecond laser pulses in synthesizing silicon nanocrystals (SiNCs) poses great potential in producing stable nanostructures with chemically pure surfaces and easy-to- manipulate optical properties. In this work, we present an approach that enhances the production and optical quality of surfactant-free SiNCs synthesized in water by ablating silicon wafer with ytterbium fiber femtosecond laser operating at different pulse energies and repetition rates. By further post-synthesis laser treatment of SiNCs suspensions, fragmentation of larger aggregates is observed leading to absorption broadening and absorption-band blueshift. Furthermore, the increase in the repetition rate, from 1 to 500 kHz, of laser pulses having energies of 20 and 240 mJ leads to a decrease in the Si wafer ablation efficiency from 35 to 1.15 pg/pulse;and from 440 to 5.2 pg/pulse, respectively. Using laser pulses with energy of 240 mJ and a repetition rate of 50 kHz results in maximum SiNCs productivity of 33 mg/h. The dependence of the nanostructures’s size and ablation efficiency on the pulse energy and repetition rate is attributed to thermal effects on the Si/water interface and within the water layer illuminated by the strong laser radiation. © 2023, The Authors. All rights reserved.

关键词： Femtosecond lasers

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Emerging Interface Effects in Flat Optics

Emerging Interface Effects in Flat Optics

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2023 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, AP-S/URSI 2023

作者： Moccia, Massimo Castaldi, Giuseppe Alù, Andrea Galdi, Vincenzo University of Sannio Department of Engineering BeneventoI-82100 Italy City University of New York Advanced Science Research Center Photonics Initiative New YorkNY10031 United States City University of New York Graduate Center Physics Program New YorkNY10016 United States

ISBN: (纸本)9781665442282

In this paper, we discuss how the manipulation and control of surface-wave propagation can be achieved in natural low-dimensional materials or metasurfaces through the engineering of planar discontinuities in the surface impedance. We present two specific examples, 'ghost line waves' and 'flat leaky waves', that offer new possibilities for controlling light at the nanoscale and may have potential applications in areas such as integrated waveguides, nonlinear optics, optical sensing, and sub-diffraction imaging. © 2023 IEEE.

关键词： Nonlinear optics

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Exploring Interface Effects in Flatland Optics 17

Exploring Interface Effects in Flatland Optics

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17th International Congress on Artificial Materials for Novel Wave Phenomena, Metamaterials 2023

作者： Moccia, M. Castaldi, G. Alu, A. Galdi, V. University of Sannio Department of Engineering BeneventoI-82100 Italy City University of New York Advanced Science Research Center Photonics Initiative New YorkNY10031 United States City University of New York Graduate Center Physics Program New YorkNY10016 United States

ISBN: (纸本)9798350332445

This study explores the possibilities of manipulating and controlling the propagation of surface waves in low-dimensional materials or metasurfaces by designing planar discontinuities in the surface impedance. Specifically, two examples are presented, namely 'flat leaky waves' and 'ghost line waves.' These innovative concepts have the potential to offer new avenues for controlling light at the nanoscale and could find practical applications in various fields ranging from integrated waveguides to optical sensing. © 2023 IEEE.

关键词： Surface waves

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Non-Hermitian metasurface for asymmetric thermal emission

Non-Hermitian metasurface for asymmetric thermal emission

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Prasad, Ciril S. Everitt, Henry O. Naik, Gururaj V. Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States U.S. Army DEVCOM Army Research Laboratory-South HoustonTX United States

ISBN: (纸本)9781957171258

Non-Hermitian optics provides a unique platform to take advantage of absorption losses in materials and control radiative properties. We demonstrate a non-Hermitian metasurface that exhibit directional suppression of thermal radiation while maintaining transmission in mid-infrared. © Optica Publishing Group 2023 © 2023 The Author(s)

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Efficiency of Non-Thermal Pulsed Emission from Eight MeV Pulsars

arXiv

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arXiv 2024年

作者： Takata, J. Wang, H.-H. Lin, L.C.-C. Kisaka, S. Department of Astronomy School of Physics Huazhong University of Science and Technology Wuhan430074 China School of Physics and Astronomy Sun Yat-sen University Zhuhai519000 China Department of Physics National Cheng Kung University Tainan701401 Taiwan Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan

We report on the properties of pulsed X-ray emission from eight MeV pulsars using XMM-Newton, NICER, NuSTAR and HXMT data. For the five among eight MeV pulsars, the X-ray spectra can be fitted by a broken-power law model with a break energy of ∼ 5 − 10 keV. The photon index below and above break energy are ∼ 1 and ∼ 1.5, respectively. In comparison with the X-ray emission of the Fermi-LAT pulsars, the MeV pulsars have a harder spectrum and a higher radiation efficiency in 0.3-10 keV energy bands. By assuming the isotropic emission, the emission efficiency in the keVMeV bands is estimated to be ηMeV ∼ 0.01 − 0.1, and it is similar to the efficiency of GeV emission of the Fermi-LAT pulsars that have similar spin-down power. To explain the observed efficiency of the MeV pulsars, we estimate the required pair multiplicity as 104−7 that depends on the emission process (curvature radiation or synchrotron radiation) and the location in the magnetosphere. The large multiplicity indicates that the secondary pairs that are created by a pair-creation process of the GeV photons produce the X-ray/soft gamma-ray emissions of the MeV pulsars. We speculate that the difference between the MeV pulsars and Fermi-LAT pulsars is attributed to the difference in viewing angle measured from the spin-axis, if the emission originates from a region inside the light cylinder (canonical gap model) or the difference in the inclination angle of the magnetic axis, if the emission is produced from equatorial current sheet outside the light cylinder. © 2024, CC0.

关键词： Pulsars

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Optimizing ethanol gas sensor with rGO layer addition on LaFeO₃–Pd doped material using density functional theory

Kuwait Journal of Science

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Kuwait Journal of Science 2025年第3期52卷

作者： Aminudin, Ahmad Az-zahra, Rumaisya Feranie, Selly Hasanah, Lilik Sahari, Siti Kudnie Suhendi, Endi Physics Study Program Universitas Pendidikan Indonesia West Java Bandung Indonesia Faculty of Engineering Universiti Malaysia Sarawak UNIMAS Kota Samarahan Sarawak 94300 Malaysia

LaFeO3 is widely applied in ethanol gas sensors due to material composition and the stability of its sensing parameters. However, LaFeO3 is still limited in gas sensing properties, necessitating doping to enhance the ... 详细信息

LaFeO₃ is widely applied in ethanol gas sensors due to material composition and the stability of its sensing parameters. However, LaFeO₃ is still limited in gas sensing properties, necessitating doping to enhance the performance of gas sensors like palladium (Pd). In this study, the optimization of the ethanol gas sensor was explored by adding reduced graphene oxide (rGO) to Pd–LaFeO₃, focusing on adsorption energy and band gap energy using density functional theory (DFT) with the generalized gradient approximation (GGA-PBEsol) simulation method. The results show that Pd–LaFeO₃ adsorption energy of −2.01 eV, which increases to −2.29 eV with the addition of rGO, indicates stronger ethanol adsorption. The band gap of Pd–LaFeO₃ was 2.34 eV before exposure to ethanol gas and decreased to 2.06 eV upon exposure. After incorporating rGO, the band gap further narrowed, from 0.11 eV before exposure to 0.05 eV after exposure. The narrowing of the energy band potentially enhances the sensor's response. Those results indicate that adding rGO to Pd–LaFeO₃ shows promising potential for ethanol gas sensor applications. © 2025 The Authors

关键词： Adsorption energy Band gap Gas sensors LaFeO3 Pd rGO

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Monitoring System for Elderly Health Care Using Smart Band, Raspberry Pi, and Node-Red 2

Monitoring System for Elderly Health Care Using Smart Band, ...

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2nd International Conference on Electronic and Electrical engineering and Intelligent System, ICE3IS 2022

作者： Ardiyanto, Yudhi Adi, Kusworo Kurnianingsih Putra, Karisma Trinanda Utomo, Pradityo System School of Postgraduate Studies Universitas Diponegoro Doctoral Program of Information Semarang Indonesia Universitas Muhammadiyah Yogyakarta Faculty of Engineering Department of Electrical Engineering Yogyakarta Indonesia Universitas Diponegoro Faculty of Science and Mathematics Department of Physics Semarang Indonesia Politeknik Negeri Semarang Faculty of Engineering Department of Electrical Engineering Semarang Indonesia Universitas Merdeka Madiun Faculty of Engineering Department of Informatics Management Madiun Indonesia

ISBN: (纸本)9781665465410

The decline in physical, cognitive, and sensory functions for most elderly people leads to the development of several health issues such as memory loss, a tendency to fall, dizziness, and reduced ability to care for oneself independently. These can be mitigated using devices designed to monitor vital signs and human activity such as a smart band. However, the application of a smart band is characterized by a disadvantage which involves storing user data in the vendor's cloud and only one device can access the client applications. Therefore, nurses, doctors, and family members cannot simultaneously analyze data and receive alerts when abnormal conditions occur in elderly patients. This study aims to develop a system capable of monitoring the health conditions of multiple elderly individuals and sending alerts during abnormal conditions based on the heart rate value read by the smart band sensor. The process involved installing a database on the Raspberry Pi to store data while a monitoring system was built on the Node-RED platform to display elderly health data and made it accessible locally. The detection of an abnormal heart rate condition in the elderly patient leads the system to send notifications via telegram to multiple receivers registered in the system using their telegram identity. © 2022 IEEE.

关键词： Heart

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engineering of dendritic dopant-free hole transport molecules:enabling ultrahigh fill factor in perovskite solar cells with optimized dendron construction

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Science China Chemistry 2021年第1期64卷 41-51页

作者： Wei Chen Yang Wang Bin Liu Yajun Gao Ziang Wu Yongqiang Shi Yumin Tang Kun Yang Yujie Zhang Weipeng Sun Xiyuan Feng Frédéric Laquai Han Young Woo Aleksandra B.Djurisic Xugang Guo Zhubing He Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Physics The University of Hong KongPokfulamHong KongChina King Abdullah University of Science and Technology KAUST Solar CenterPhysical Sciences and Engineering DivisionMaterial Science and Engineering ProgramThuwal 23955-6900Kingdom of Saudi Arabia Department of Chemistry Korea UniversitySeoul 02841South Korea

Developing dopant-free hole-transporting materials(HTMs)for high-performance perovskite solar cells(PVSCs)has been a very active research topic in recent years since HTMs play a critical role in optimizing interfacial charge carrier kinetics and in turn determining device ***,a novel dendritic engineering strategy is first utilized to design HTMs with a D-A type molecular framework,and diphenylamine and/or carbazole is selected as the building block for constructing *** HTMs show good thermal stability and excellent film morphology,and the key optoelectronic properties could be fine-tuned by varying the dendron *** them,MPA-Cz-BTI and MCz-Cz-BTI exhibit an improved interfacial contact with the perovskite active layer,and non-radiative recombination loss and charge transport loss can be effectively ***,high power conversion efficiencies(PCEs)of 20.8%and 21.35%are achieved for MPA-Cz-BTI and MCz-Cz-BTI based devices,respectively,accompanied by excellent long-term storage *** encouragingly,ultrahigh fill factors of 85.2%and 83.5%are recorded for both devices,which are among the highest values reported to *** work demonstrates the great potential of dendritic materials as a new type of dopant-free HTMs for high-performance PVSCs with excellent FF.

关键词： dendritic molecules hole-transporting materials dopant-free ultrahigh fill factor perovskite solar cells

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