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Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society 2023年第4期41卷 348-355页

作者： Nakawaki, Hiroki Tatsumi, Hiroaki Nitta, Shunya Yang, Chih-Han Lin, Shih-Kang Nishikawa, Hiroshi Joining and Welding Research Institute Osaka University Japan Graduate School of Engineering Osaka University Japan Department of Material Science and Engineering National Cheng Kung University Taiwan

In recent years, low-melting-temperature solders are required in electronics packaging. Among them, Sn-Bi alloys are expected to exhibit good wettability and strength. However, they have difficulty in ductility due to the brittle nature of Bi. In some research, to improve the mechanical property of Sn-Bi alloys, Zn and In are added. The modified alloy had better mechanical properties and the low-melting-temperature equivalent to Sn-58Bi. However, its ductility is not comparable to that of typical lead-free solder, Sn-3.0Ag-0.5Cu. Therefore, in this study, by reducing the content of Bi, we attempt to improve the ductility of Sn-Bi-Zn-In alloy. To investigate the effect of Bi content on the melting temperature, microstructure, and tensile strength were evaluated using Sn-xBi-2.6Zn-1.0In (x=45, 40, 35, 30, 25, 20 mass%) alloys. In addition, the fracture surfaces and nearby microstructures were observed to analyze the effect of the Bi content. As a result, the melting onset and offset temperatures increased with reducing the Bi content. In all alloys, the microstructures had Sn-rich phases, Bi-rich phases and Zn phases. As the Bi content was reduced, the morphology of Bi phase changed from layer-like eutectic phases to small round shape. Reducing the Bi content from 45 to 35 mass%, the ductility improved. However, with the decreasing Bi content from 35 to 20 mass%, the ductility was getting worse. The fracture surface analyses indicated that, their ductility was affected by the Bi-rich phase morphologies. Based on these results, the ductility enhancement with the enhancement with the 35 mass% Bi content would be understandable with the strain dispersion by the refined Bi-rich phases. The strength slightly increased decreasing the Bi content due to the decrease in the Sn-rich/Bi-rich phases interface. © 2023 Japan Welding Society. All rights reserved.

关键词： Tensile strength

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CFD Modelling of Solidification and Melting of Bath During Raft Formation

CFD Modelling of Solidification and Melting of Bath Durin...

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Light Metals Symposium held at the TMS Annual Meeting and Exhibition, TMS 2023

作者： Gylver, Sindre Engzelius Einarsrud, Kristian Etienne Department of Material Science and Engineering NTNU Alfred Getz’ veg 2 Trondheim7034 Norway

ISBN: (纸本)9783031225314

The dissolution of alumina in cryolite is a complex process, and better understanding is needed to ensure stable cell conditions and high energy efficiency. Additions of cold powder result in freezing of bath that hinders dissolution, and creation of rafts. The current work aims to develop and demonstrate a CFD framework in OpenFOAM for freezing of bath on a fed dose of alumina, based on the volume of fluid (VOF) method, where appropriate source- and sink terms are applied. Essential features have been verified by comparison with a Stefan problem, while simulating the dose as a floating rigid object demonstrate that a larger layer of freeze increase the damping of its movement. When simulating the dose as an immiscible fluid, spreading will hinder enough freeze to be formed around the dose. Hence, the added source terms behave as intended, but improvements on the alumina-bath interactions are needed. © 2023, The Minerals, Metals & materials Society.

关键词： Alumina

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Highly efficient ternary organic solar cells with excellent open-circuit voltage and fill factor via precisely tuning molecular stacking and morphology

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science China Chemistry 2024年第3期67卷 963-972页

作者： Dinghong Sun Zhenyu Chen Jianfeng Zhang Wei Song Jingyu Shi Jintao Zhu Yuanyuan Meng Fei Jin Shuncheng Yang Ziyi Ge Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China Faculty of Material Science and Chemical Engineering Ningbo UniversityNingbo 315211China Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology&EngineeringChinese Academy of SciencesNingbo 315201China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049China Department of Chemical and Environmental Engineering University of Nottingham NingboNingbo 315100China

The micro-morphology and molecular stacking play a key role in determining the charge transport process and nonradiative energy loss, thus impacting the performances of organic solar cells(OSCs). To address this issue, a non-fullerene acceptor PhC6-IC-F with alkylbenzene side-chain, possessing optimized molecular stacking, complementary absorption spectra and forming a cascade energy level alignment in the PM6:BTP-eC9 blend, is introduced as guest acceptor to improve efficiency of ternary OSCs. The bulky phenyl in the side-chain can regulate crystallinity and optimizing phase separation between receptors in ternary blend films, resulting in the optimal phase separations in the ternary films. As a result, high efficiencies of 18.33% as photovoltaic layer are obtained for PhC6-IC-F-based ternary devices with excellent fill factor(FF) of 78.92%. Impressively, the ternary system produces a significantly improved open circuit voltage(V_(oc)) of 0.857 V compared with the binary device,contributing to the reduced density of trap states and suppressed non-radiative recombination result in lower energy loss. This work demonstrates an effective approach for adjusting the aggregation, molecular packing and fine phase separation morphology to increase V_(oc) and FF, paving the way toward high-efficiency OSCs.

关键词： alkylbenzene side-chain morphology regulation ternary blends organic solar cells

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Nanostructured OLED Photonics 18

Nanostructured OLED Photonics

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18th IEEE Nanotechnology materials and Devices Conference, NMDC 2023

作者： So, Franky North Carolina State University Department of Material Science and Engineering RaleighNC United States

ISBN: (纸本)9798350335460

It has been challenging to measure the optical modes in an OLED. Here, we will describe how we use angle-resolved electroluminescence spectroscopy (ARES) to directly measure the optical modes of a nanostructured OLED. Specifically, we use ARES to measure the cavity modes in a planar OLED and measure the waveguide modes and surface plasmon polariton (SPP) modes of a nanostructured OLED. With this technique, we can determine how different optical modes are extracted due to different photonic crystals. © 2023 IEEE.

关键词： Electromagnetic wave polarization

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Potential use of Ulva intestinalis-derived biochar adsorbing phosphate ions in the cultivation of winter wheat Tristicum aestivum

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Bioresources and Bioprocessing 2024年第1期11卷 371-394页

作者： Natalia Niedzbała Ewa Lorenc-Grabowska Piotr Rutkowski Jacek Chęcmanowski Anna Szymczycha-Madeja Maja Wełna Izabela Michalak Department of Advanced Material Technologies Faculty of ChemistryWrocław University of Science and TechnologyWrocławPoland Department of Process Engineering and Technology of Polymer and Carbon Materials Faculty of ChemistryWrocław University of Science and TechnologyWrocławPoland Department of Analytical Chemistry and Chemical Metallurgy Faculty of ChemistryWrocław University of Science and TechnologyWrocławPoland

In this work,the properties of biochar produced from green macroalga Ulva intestinalis by pyrolysis were studied at temperatures of 300,500,and 700°*** biochar was characterized in terms of multielemental composition,BET surface area,total pore volume,and biosorption properties toward phosphate *** produced at 700°C-25 m2/g had the highest surface *** kinetics and isotherms of sorption processes of phosphate ions as sorbate by these sorbents were *** biochar was able to remove 84.3%of phosphate ions from wastewater,whereas non-modified biochar-only 40.6%.Hence,biochar enriched with phosphate ions can serve as a valuable soil *** experiments performed on winter wheat(Triticum aestivum)with a 3%addition of dry Ulva intestinalis,pristine biochar,and Mg-modified biochar enriched with phosphate ions showed that these amendments stimulated plant growth(length and fresh weight of plants)as well as enlarging the chlorophyll content in *** results indicate that the production of biochar(pristine and Mg-impregnated)is a sustainable option to valorize the biomass of seaweeds,and to recycle phosphorus from wastewater.

关键词： Green seaweed Pyrolysis Biochar Phosphate ions Wastewater treatment Soil additives

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Enhancement of strength and ductile-brittle transition temperature of SA508 Gr.3 low-alloy steel by controlling heat accumulation in laser powder-directed energy deposition

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Journal of materials science & Technology 2024年第35期202卷 240-252页

作者： Wonjong Jeong Young-Bum Chun Suk Hoon Kang Chang Kyu Rhee Chang Hyoung Yoo Seongjin Yoo Hongmul Kim Muhammad Akmal Ho Jin Ryu Department of Nuclear and Quantum Engineering Korea Advanced Institute of Science and TechnologyYuseong-guDaejeon34141Republic of Korea Korea Atomic Energy Research Institute Yuseong-guDaejeon34057Republic of Korea Advanced powder technology team HANA AMTCheongwon-guCheongju-si28126Republic of Korea Department of Material Science and Engineering Korea Advanced Institute of Science and TechnologyYuseong-guDaejeon34141Republic of Korea

The safety and longevity of small modular reactors are affected by reactor pressure vessels,which are complex integral components made of SA508 Gr.3 low-alloy *** this study,the impacts of heat accumulation on the microstructural and mechanical characteristics(tensile properties and Charpy V-notched impact energy)of SA508 Gr.3 steel fabricated using laser powder-directed energy deposition were *** samples were prepared using long raster and short raster scanning strate-gies for changing heat buildup,and the mechanical tests were conducted depending on build *** time-temperature profile measured at a fixed point in the long raster sample showed a lower max-imum temperature and a higher cooling rate,indicating lower heat accumulation compared to that of the short raster *** each build direction,the yield strength of the long raster sample was 45.8%-60.5%higher and its ductile-brittle transition temperature was 76.8-103.8℃ lower than that of the short raster ***,compared to conventionally made samples and without requiring heat treat-ment,the long raster sample exhibited over a 45%increase in yield strength and a 22.7℃ reduction in the ductile-brittle transition *** superior combination in long raster samples is induced by smaller effective grain size,smaller cementite,and a higher pre-existing dislocation *** re-sults emphasize the importance of controlling heat accumulation throughout the additive manufacturing process and provide valuable insights into the use of additive manufacturing for manufacturing reactor pressure vessels in the nuclear industry.

关键词： Reactor pressure vessel Laser powder directed energy deposition SA508 Gr.3 Low-alloy steel Heat accumulation Ductile-brittle transition temperature

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All-fluorinated electrolyte for non-flammable batteries with ultra-high specific capacity at 4.7 V

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Green Energy & Environment 2024年第10期9卷 1601-1609页

作者： Zhe Wang Zhuo Li Jialong Fu Sheng Zheng Rui Yu Xiaoyan Zhou Guanjie He Xin Guo State Key Laboratory of Material Processing and Die&Mould Technology Laboratory of Solid State IonicsSchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Electrochemical Innovation Lab Department of Chemical EngineeringUniversity College London20 Gordon StreetLondon WC1E 7JEUK

Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge ***,high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces,thus significantly degrading the cycling lifespan and decreasing the specific ***,we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl)borate(TFEB),based on 3,3,3-fluoroethylmethylcarbonate(FEMC)and fluoroethylene carbonate(FEC),which enables stable cycling of high nickel cathode(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),NMC811)under a cut-off voltage of 4.7 V in Li metal *** electrolyte not only shows the fire-extinguishing properties,but also inhibits the transition metal dissolution,the gas production,side reactions on the cathode ***,the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode,delivering a specific capacity>220 mA h g^(-1),an average Coulombic efficiency>99.6%and capacity retention>99.7%over 100 cycles.

关键词： Fluorinated electrolyte Li metal batteries Solid electrolyte interphase Cathode electrolyte interphase Coulombic efficiency

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Development of a novel quality control indicator for coffee roasting based on the digitalization of smell by a portable electronic nose 20

Development of a novel quality control indicator for coffee ...

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20th International Joint Conference on Computer science and Software engineering, JCSSE 2023

作者： Somaudon, Varanya Sakuldee, Pathapee Kerdcharoen, Teerakiat Materials Science and Engineering Program Mahidol University Faculty of Science Bangkok Thailand School of Science Material Engineering Mae Fah Luang University Chiang rai Thailand Mahidol University Faculty of Science Department of Physics Bangkok Thailand

ISBN: (纸本)9798350300505

Northern Thailand is home to several Arabica coffee-growing regions, including Mae-kampong, Teentok, Mae-lord, and Monngo Valleys, whose coffees are featured throughout this study. These coffees have distinct aromas and flavors due to their varied cultivation locations, which are influenced by unique climatic conditions. The purpose of this paper is to comprehend the aroma of coffees brought from various locations and roasted under the same conditions. Our lab-made electronic nose (e-nose) was used to digitalize and analyze the smell of coffee. In order to monitor the coffee scent throughout roasting and assess how similar the aromas of coffee samples taken from various locations are to one another, principal component analysis and hierarchical cluster analysis were used. It was found that our e-nose system is an effective tool for determining the geo-location of the coffee origin as well as for quality control of coffee production. © 2023 IEEE.

关键词： Electronic nose

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Perturbation Methods for Solving Non-Linear Ordinary Differential Equations

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IAENG International Journal of Applied Mathematics 2024年第10期54卷 2070-2082页

作者： Hijazi, Malak Ajeel, Mahmood Shareef Al-Khaled, Kamel Al-Khalid, Hala Department of Mathematics and Statistics Jordan University of Science and Technology Irbid22110 Jordan Department of Material Engineering College of Engineering Shatrah University Thi-Qar64001 Iraq Jordan University of Science and Technology Irbid22110 Jordan Western Michigan University KalamazooMI49008-5248 United States

The goal of this paper is to use general perturbation theory that is, singular perturbation theory and regular perturbation theory to solve both linear and nonlinear differential equations. We initially demonstrate the regular perturbation method’s application to the classification of nonlinear differential equations in order to demonstrate its efficacy. Next, in the event that normal perturbation approaches prove fruitless, we employ and demonstrate Lindstedt-Poincaré and singular perturbation methods to approximate periodic solutions to nonlinear ordinary differential equations. Upon computing the approximate solutions by Lindstedt-Poincaré, or by singular perturbation methods, we compare it with the exact solution found using MATHEMATICA software, we determine the absolute error and demonstrate the accuracy of our approach. © (2024), (International Association of Engineers). All rights reserved.

关键词： Perturbation techniques

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Quantum spin Hall effect protected by spin U(1) quasisymmetry

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Physical Review B 2024年第16期110卷 L161104页

作者： Lu Liu Yuntian Liu Jiayu Li Hua Wu Qihang Liu Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE) Laboratory for Computational Physical Sciences (MOE) State Key Laboratory of Surface Physics and Department of Physics Shanghai Qi Zhi Institute Shanghai 200232 China Nanjing 210093 China Guangdong Provincial Key Laboratory of Computational Science and Material Design

Quantum spin Hall (QSH) insulators, with their unique helical edge states where counterpropagating edge channels possess opposite spins, have attracted broad interest across various fields. While the exact quantization of spin Hall conductance (SHC) is elusive in realistic materials due to intrinsic spin mixing effects, the near quantization, as a compromised definition of the QSH effect, cannot be captured by rigorous topological invariants. In this Letter, we present a universal symmetry indicator for diagnosing the QSH effect in realistic materials, termed spin U(1) quasisymmetry. Such a symmetry eliminates the first-order spin-mixing perturbation and thus protects the near-quantization of SHC, applicable to time-reversal-preserved cases with either Z2=1 or Z2=0, as well as time-reversal-broken scenarios. We propose that spin U(1) quasisymmetry is hidden in the subspace spanned by the doublets with unquenched orbital momentum and emerges when SOC is present, which can be realized in 19 crystallographic point groups. Our theory is applied to identify previously overlooked QSH phases such as time-reversal-preserved even spin Chern phase and time-reversal-broken phase, as exemplified by twisted bilayer transition metal dichalcogenides, monolayer RuBr3, and monolayer FeSe. Our work provides a comprehensive symmetry-based framework for understanding the QSH effect and significantly expands the material pool for the screening of exemplary material candidates.

关键词： Electronic structure First-principles calculations Symmetry protected topological states Topological materials Dichalcogenides Two-dimensional electron system Z_2 symmetry

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