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Electric field control of phonon angular momentum in perovskite BaTiO3

Physical Review materials 2022年第10期6卷 104410-104410页

作者： Kevin Moseni Richard B. Wilson Sinisa Coh Materials Science and Engineering University of California Riverside Riverside California 92521 USA Mechanical Engineering University of California Riverside Riverside California 92521 USA

We find that in BaTiO3 the phonon angular momentum is dominantly pointing in directions perpendicular to the electrical polarization. Therefore, the external electric field in ferroelectric BaTiO3 does not control only the direction of electrical polarization but also the direction of the phonon angular momentum. This finding opens up the possibility of electric field control of physical phenomena that depend on phonon angular momentum. We construct an intuitive model, based on our first-principles calculations, that captures the origin of the relationship between phonon angular momentum and electric polarization.

关键词： Crystal symmetry Electric polarization Phonons Noncentrosymmetric materials Perovskites Angular momentum Polarization First-principles calculations Inversion symmetry Models based on symmetries

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Insights into the Effect of Ni Doping on In2S3 for Enhanced Activity and Selectivity of Photocatalytic CO2 Reduction

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SSRN 2024年

作者： Guo, Biao Liu, Liyuan Li, Ai Li, Xinlin Chang, Yue Jiao, Zhengbo Han, Minmin National Engineering Research Center for Intelligent Electrical Vehicle Power System College of Mechanical and Electrical Engineering Qingdao University Shandong Qingdao266071 China Institute of Materials for Energy and Environment College of Material Science and Engineering Qingdao University Qingdao266071 China College of Mechanical and Electrical Engineering Qingdao University Qingdao266071 China Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing100083 China

In this work, we developed the Ni-doped In2S3 nanotube photocatalysts for enhanced photocatalytic CO2 reduction performance. The introduction of Ni element into the lattice of In2S3 could significantly improve the photocatalytic activity and selectivity without the destruction of the hollow-nanotube structure of In2S3. A high yield of 243.2 μmol/g/h for CO was achieved under visible light, which is 8.2 times that of the pure In2S3. Moreover, by modulating the doping amount of Ni element, the selectivity of CO varied from 27.7% to 51.0%. Further characterizations were performed regarding to the enhancement in activity and selectivity. The doping of Ni element altered the electronic bandgap arrangement of In2S3, where the position of the conduction band is conducive to the activation of CO2 molecules. Moreover, the defect level resulting from Ni-doping not only facilitates the separation of photoexcited electron-hole pairs but also suppresses the recombination of electrons and holes. Therefore, the photocatalytic CO2 reduction performance is improved. This study provides an available and reliable strategy for enhancing the photocatalytic CO2 reduction performance of related sulfide photocatalytic materials in future studies. © 2024, The Authors. All rights reserved.

关键词： Sulfur compounds

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Photoresponse of Thermally Evaporated Copper Oxide-Based Solar Cells 1

Photoresponse of Thermally Evaporated Copper Oxide-Based Sol...

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1st Middle East and North Africa Solar Conference, MENA-SC 2023

作者： Alami, Abdul Hai Ayoub, Mohamad Alashkar, Adnan Alasad, Shamma Mdallal, Ayman Khuri, Siren Aljaghoub, Haya University of Sharjah Sustainable Energy & Power Systems Research Centre Sustainable and Renewable Energy Engineering Department Sharjah United Arab Emirates American University of Sharjah Materials Science and Engineering PhD Program Sharjah United Arab Emirates American University of Sharjah Mechancial Engineering Department Sharjah United Arab Emirates University of Sharjah Sustainable Energy & Power Systems Research Centre Sharjah United Arab Emirates University of Sharjah Industrial Engineering and Engineering Management Department Sharjah United Arab Emirates

ISBN: (纸本)9781665491464

This study reports on the fabrication and characterization of a copper oxide (CuO)-based photoactive cell. Copper was thermally evaporated onto two substrates and post-treated using chemical and thermal treatments to obtain different semiconducting types of CuO. Absorption measurements were conducted to obtain the bandgaps of CuO, which were found to be 1.51 eV and 1.21 eV, for the chemically and thermally treated CuO, respectively. Finally, a chronoamperometry test was conducted to confirm the photoresponse of the cell, which showed a doubling of output current values under light conditions compared to dark conditions. © 2023 IEEE.

关键词： Copper oxides

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Tailored morphology of indium-doped titania via sol-gel method for enhanced photocatalysis

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Ceramics International 2025年第16期51卷 21590-21599页

作者： Rehman, Junaid ur Zeng, Yilan Javed, Sofia Gohar, Osama Ahmad, Awais Bouyer, Melany Mujahid, Mohammad Motola, Martin H-12 Islamabad44000 Pakistan Texas State University San MarcosTX78666 United States Department of Inorganic Chemistry Faculty of Natural Sciences Comenius University Bratislava Ilkovicova 6 Bratislava842 15 Slovakia Department of Environmental Ecology and Landscape Management Faculty of Natural Sciences Comenius University Bratislava Mlynska Dolina Ilkovicova 6 Bratislava842 15 Slovakia Department of Mechanical and Electrical Systems Engineering of Engineering Kyoto University of Advanced Science Gotanda-cho Yamanouchi Ukyo-ku Kyoto 615-8577 Japan Department of Chemistry The University of Lahore Lahore Pakistan Department of Chemistry and Biochemistry Texas State University San MarcosTX78666 United States Department of Materials Science and Engineering Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology Mang Khyber Pakhtunkhwa Haripur22601 Pakistan Center for Nanotechnology and Advanced Materials Faculty of Mathematics Physics and Informatics Comenius University Bratislava Mlynska Dolina Bratislava842 48 Slovakia

This study investigates the photocatalytic decomposition of methylene blue (MB) using indium-doped titania nanoparticles (TiO2 NPs), synthesized via the sol-gel reflux method, and explores their potential in heterojunction photocatalysis. Titanium tetraisopropoxide was utilized as the precursor, with indium (In) incorporated in varying concentrations (0.25, 0.50, and 0.75 wt%) to enhance photocatalytic activity. Scanning electron microscopy and atomic force microscopy that revealed particle sizes ranging from 12 to 22 nm. X-ray diffraction and Raman spectroscopy confirmed the formation of phase-pure nanocrystalline anatase TiO2. Fourier transform infrared spectroscopy verified the presence of Ti-O-Ti bonding characteristic of the anatase phase. Surface area analysis indicated an increase in surface area with indium doping, rising from 102.9982 m2/g (0.25 wt% In-doped) to 104.5035 m2/g (0.50 wt% In-doped) and reaching 109.8041 m2/g at the highest concentration. Optical properties revealed a corresponding decrease in bandgap energy, which dropped from 3.31 eV (pure TiO2) to 2.97 eV (0.75 wt% In-doped). The results demonstrated that indium doping significantly enhanced the overall photocatalytic degradation of MB, 85 % degradation was achieved after 8 h of UV irradiation at 0.25 wt% In-doped TiO2, making indium-doped titania a promising material for photocatalytic applications. © 2025 The Authors

关键词： Fourier transform infrared spectroscopy

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Nonreciprocity of acoustic intensity in viscous fluids

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Physical Review B 2025年第10期111卷 104317-104317页

作者： Yuqi Jin Arkadii Krokhin Teng Yang Tae-Youl Choi Arup Neogi Department of Physics University of North Texas P. O. Box 311427 Denton Texas 76203 USA Department of Materials Science and Engineering University of North Texas Denton Texas 76207 USA Department of Mechanical Engineering University of North Texas Denton Texas 76207 USA

A mechanism of nonreciprocal transmission of sound through a viscous environment with asymmetric scatterers is proposed and experimentally demonstrated using a Tesla valve filled by stationary liquids with different viscosities. The nonreciprocal quantity is the local intensity of sound. Unlike pressure, which remains reciprocal even in a viscous fluid, the intensity exhibits nonreciprocity due to the asymmetry of the field of acoustic velocities if the mirror symmetry (P symmetry) is broken by asymmetric scatterers. Nonreciprocity in intensity appears in the linear regime of propagation, while the intensity itself scales quadratically with the amplitude of sound. Our study supports the general conclusion that Newton's dynamics of a system with broken time-reversal symmetry (T symmetry) is nonreciprocal. Due to the irreversibility of viscous fluid dynamics, the dissipation-induced nonreciprocity does not follow Onsager symmetry, unlike nonreciprocity caused by fluid motion or magnetic field.

关键词： Viscosity of liquids

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Strengthening Mechanism of Powder Metallurgy Hot-rolled Ti-Zr-TiC Composites

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Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 2024年第10期71卷 492-498页

作者： Miyamoto, Sei Kariya, Shota Umeda, Junko Chen, Biao Shen, Jianghua Li, Shufeng Alhazaa, Abdulaziz N. Kondoh, Katsuyoshi Dept. Mechanical Engineering Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita565-0871 Japan Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki 567-0047 Japan State Key Laboratory of Solidification Processing Northwestern Polytechnical University Shaanxi Xi'an710072 China School of Aeronautics Northwestern Polytechnical University Shaanxi Xi'an710072 China School of Materials Science and Engineering Xi'an University of Technology NO.5 South Jinhua Road Xi'an710048 China King Abdullah Institute for Nanotechnology King Saud University P.O BOX 2455 Riyadh11451 Saudi Arabia

The microstructural and mechanical properties investigation on powder metallurgy (PM) Ti-Zr composite alloys dispersed with TiC particles via sintering and hot rolling process was carried out in this study. PM Ti-Zr-TiC composites were fabricated from the pre-mixed pure Ti, metal Zr and TiC powders, and heat treatment was applied to the sintered materials to homogenize Zr solid-solution in α-Ti matrix. XRD analysis results of these rolled composite materials indicated complete solid-solution of Zr elements. Microstructures observation clarified the binary Ti-(10-20%)Zr alloys had a mean grain size of around 4 µm, which was much smaller compered to pure Ti material with 10 µm grain diameter. According to the tensile test results, Ti-Zr alloys showed a remarkable increment of tensile strength due to Zr solid-solution and α-Ti grain refinement, and also had a large elongation. On the other hand, since Young's modulus gradually decreased with increased in Zr content, TiC particles were added into Ti-10%Zr alloy to improve the modulus. The uniform dispersion of (2.5-5 wt%)TiC particles in the matrix resulted in the increase of both Young's modulus and tensile strength. The experimental values of Young's modulus showed a good agreement with the calculated ones by using the law of mixture. © 2024 Journal of the Japan Society of Powder and Powder Metallurgy. All rights reserved.

关键词： Tensile strength

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Tribological behaviour of LM25 hybrid metal matrix composites by using Taguchi’s techniques

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materials Today: Proceedings 2022年 50卷 1827-1834页

作者： Amol S. Mali S.T. Vagge Aniket Kolekar Department of Metallurgy and Materials Science College of Engineering Pune 411005 India Department of Mechanical Engineering DYPIEMR Akurdi Pune 411044 India

In the competitive industrial world, the composite materials have vast scope due to its mechanical and wear characteristics like strength, hardness, toughness, wear in micron and coefficient of friction. Conventional monolithic general materials have limitations concerning recently advanced materials like composite as well as Hybrid composite materials. The innovation of hybrid metal matrix composite has become an exciting task in material science and metallurgy . Aluminum alloy composites are primarily utilized in the car and the aerospace industry due to their excellent mechanical characteristics, including greater stiffness, low density, excellent corrosion resistance, and significant wear resistance. So in the present research, Wear and frictional characteristics of aluminum alloy-based hybrid composite material has been investigated with the help of tribometer testing apparatus. Tribological behavior of LM25 reinforced with Fly ash and Alumina with a varying percentage from 4%, 8%, 12% manufactured with stir casting technique and studied. The study was planned on Taguchi's approach, and the L9 array has been used for experimentation. In this research, experiments were conducted as per ASTM-G99 standard and with pin-on-disk (POD) tribo testing machine for characterization of Hybrid metal matrix composite. The speed of disc has the most significant impact, on the wear in micron after that the Normal loads and the reinforcement percentage. The reinforcement percentage shows more effect on coefficient of friction in hybrid composite material. The SEM images shows that abrasive wear of Hybrid composite material occur during Sliding wear of specimen on Pin-on-disc apparatus. The validation of results was done with the help of SEM (Scanning Electron Microscope) studies with the experimental results.

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Enhancing the detection capabilities of nano-avalanches via data-driven classification of acoustic emission signals

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Physical Review E 2023年第4期108卷 045001-045001页

作者： Emil Bronstein Jonathan Zimmerman Eugen Rabkin Eilon Faran Ronen Talmon Doron Shilo Faculty of Mechanical Engineering Technion–Israel Institute of Technology 3200003 Haifa Israel Department of Materials Science and Engineering Technion–Israel Institute of Technology 3200003 Haifa Israel Viterbi Faculty of Electrical and Computer Engineering Technion–Israel Institute of Technology 3200003 Haifa Israel

Acoustic emission (AE) is a powerful experimental method for studying discrete and impulsive events termed avalanches that occur in a wide variety of materials and physical phenomena. A particular challenge is the detection of small-scale avalanches, whose associated acoustic signals are at the noise level of the experimental setup. The conventional detection approach is based on setting a threshold significantly larger than this level, ignoring “false” events with low AE amplitudes that originate from noise. At the same time, this approach overlooks small-scale events that might be true and impedes the investigation of avalanches occurring at the nanoscale, constituting the natural response of many nanoparticles and nanostructured materials. In this work, we develop a data-driven method that allows the detection of small-scale AE events, which is based on two propositions. The first includes a modification of the experimental conditions by setting a lower threshold compared to the conventional threshold, such that an abundance of small-scale events with low amplitudes are considered. Second, instead of analyzing several conventional scalar features (e.g., amplitude, duration, energy), we consider the entire waveform of each AE event and obtain an informative representation using dynamic mode decomposition. We apply the developed method to AE signals measured during the compression of platinum nanoparticles and demonstrate a significant enhancement of the detection range toward small-scale events that are below the conventional threshold.

关键词： Acoustic measurements Acoustic signal processing & noise Disclinations & dislocations Plasticity Nanoparticles Acoustic techniques

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Investigation of the Effect of Partial Co Substitution by Ni and Fe on the Interface Bond Strength of WC Cemented Carbide Based on First-Principles Calculations

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SSRN 2024年

作者： Li, Hongnan Zhang, Hongmei Jiang, Zhengyi School of Materials and Metallurgy University of Science and Technology Liaoning Anshan114051 China School of Mechanical Materials Mechatronic and Biomedical Engineering University of Wollongong WollongongNSW2522 Australia

In this work, the effect of Ni and Fe replacing part of Co on the interfacial properties of WC cemented carbides was evaluated by using first-principles calculations and WC/Co and WC/CoNiFe cemented carbides were prepared by powder metallurgy. The effects of replacing part of the Co by Ni and Fe on the interfacial electronic structure, interfacial bond strength, microstructure and mechanical properties of WC cemented carbides was investigated by establishing the WC/Co and WC/CoNiFe interfacial models and examining the porosity, KPFM and microhardness of the actual samples. The results indicate that the substitution of partial Co by Fe and Co has little effect on the interface binding energy and interface structure of WC cemented carbides. Co, Ni, and Fe atoms can all form strong covalent and metallic bonds with W atoms, with atomic bonding strength W-Fe>W-Co>W-Ni. Fe atoms play a major role in the strength of the WC/CoNiFe interface. The porosity of the WC/CoNiFe cemented carbide sample is 0.78%, which is significantly smaller than that of the WC/Co cemented carbide and the porosity distribution is relatively homogeneous. The hardness of WC/CoNiFe cemented carbide is lower (1182 HV) than that of the WC/Co cemented carbide (1320 HV) but the distribution is much more uniform than that of the WC/Co cemented carbide. © 2024, The Authors. All rights reserved.

关键词： Binary alloys

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Effects of Bi-dopant and co-catalysts upon hole surface trapping on La_(2)Ti_(2)O_(7) nanosheet photocatalysts in overall solar water splitting

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Nano Research 2022年第1期15卷 438-445页

作者： Xiaoyan Cai Liang Mao Mamoru Fujitsuka Tetsuro Majima Sujan Kasani Nianqiang Wu Junying Zhang School of Materials Science and Physics Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology and EquipmentChina University of Mining and TechnologyXuzhou 221116China School of Physics Beihang UniversityBeijing 100191China The Institute of Scientific and Industrial Research(SANKEN) Osaka UniversityMihogaoka 8-1IbarakiOsaka 567-0047Japan Department of Mechanical and Aerospace Engineering West Virginia UniversityMorgantownWV 26506-6106USA Department of Chemical Engineering University of Massachusetts AmherstAmherstMA 01003-9303USA

Pristine and Bi-doped lanthanum titanium oxide(La_(2)Ti_(2)O_(7))nanosheets have been synthesized as photocatalysts for overall solar water *** surface hole trap is a critical factor that limits the photocatalytic activity of pristine La_(2)Ti_(2)O_(7)-Deposition of cobalt phosphate(Co-Pi)and platinum(Pt)nanoparticles on La_(2)Ti_(2)O_(7) cannot remove the surface traps although they are essential for enabling the oxygen and hydrogen evolution *** is interesting that doping bismuth(Bi)into La_(2)Ti_(2)O_(7) nanosheets has eliminated the surface traps due to surface enrichment of *** Co-Pi/Bi-La_(2)Ti_(2)O_(7)/Pt nanosheets exhibit increasing photocatalytic activity toward overall water splitting with increasing the Bi-dopant level up to 5 at.%.Further increasing the Bi-dopant level leads to the formation of localized states above the valence band,leading to the lifetime reduction of photogenerated charge-carriers,and jeopardizing the photocatalytic *** work proposes an effective strategy to address the surface trapping and surface catalysis issues in the nanostructured metal oxide photocatalysts.

关键词： photocatalyst water splitting surface trap co-catalyst solar fuel

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