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SSRN 2022年

作者： Li, Fengji Yu, Xiuhan Shi, Xunwang Sun, Deen Du, Hongji Shao, Yong Wang, Jinbiao Zhang, Sam Center for Advanced Thin Films and Devices School of Materials and Energy Southwest University 2 Tiansheng Road Chongqing Beibei400715 China Beijing Vikaitech Ltd. 6 Caiyuan Road Nancai Town Shunyi District Beijing101399 China School of Materials Science and Engineering Jiangsu University of Science and Technology Jiangsu Zhenjiang212100 China Chongqing Key Laboratory of Materials Surface & Interface Science Chongqing University of Arts and Sciences Chongqing Yongchuan402160 China

The oxidation resistance of MoSi2 coating is challenged by the diffusion of Si elements towards the substrate and the "pesting" behavior caused by evaporation of MoO3. To solve these problems, this work prepared an MoSi2(N) interlayer on the Mo substrates as the diffusion barrier, followed by deposition of Si-doped MoSi2 (i.e., MoSi2(Si)) layer to suppress the "pesting" behavior. The as-deposited coatings were annealed subsequently at 1000℃ in an Ar atmosphere to obtain a stable structure. To evaluate the oxidation resistance, the as-annealed coating was heated in a muffle furnace in air at 700℃, 1000℃ and 1200℃ for different durations. The coating structure, surface morphology, cross section and chemical composition were examined by X-ray diffraction, field emission scanning electron microscopy, and energy dispersive spectroscopy. The results showed the MoSi2(N) interlayer was amorphous and kept the most stable thermal stability at Ar/N2 flow rate of 20/20 sccm. It effectively blocked the downward diffusion of Si. Free state Si elements only diffused towards the coating surface. "Pesting" pores in the MoSi2(Si) layer were repaired by the growth of SiO2 layer via the preferential oxidation of Si. The mechanism for the enhanced oxidation resistance was explained through a model. © 2022, The Authors. All rights reserved.

关键词： Oxidation resistance

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Correction: Synergistic Effects of Pre-charged Hydrogen and Tensile Stress on the Stress Corrosion Cracking of 2024-T351 Aluminum Alloy

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JOM 2024年第2期77卷 969-969页

作者： He, Qiyao Liang, Yuexing Chen, Junzhou Wang, Xiaoya Shao, Wenzhu Jiang, Jiantang Zhen, Liang School of Materials Science and Engineering Harbin Institute of Technology Harbin China Oil and Gas Engineering Research Institute PetroChina Tarim Oilfield Company Korla China Beijing Institute of Aeronautical Materials Beijing China Beijing Engineering Research Center of Advanced Aluminum Alloys and Application Beijing China Institute of Special Environments Physical Sciences Harbin Institute of Technology (Shenzhen) Shenzhen China National Key Laboratory of Precision Hot Processing of Metals Harbin Institute of Technology Harbin China

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Synergy of Photogenerated Electrons and Holes toward Efficient Photocatalytic Urea Synthesis from CO2and N2

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Angewandte Chemie 2024年第32期136卷

作者： Yida Zhang Dr. Yingjie Sun Qingyu Wang Dr. Zechao Zhuang Zhentao Ma Limin Liu Prof. Gongming Wang Prof. Dingsheng Wang Prof. Xusheng Zheng National Synchrotron Radiation Laboratory University of Science and Technology of China Anhui 230029 China College of Chemistry and Materials Science University of Science and Technology of China Anhui 230026 China Hebei Key Laboratory of Photoelectric Control on Surface and Interface College of Science Hebei University of Science and Technology Hebei 050018 China Engineering Research Center of Advanced Rare Earth Materials Department of Chemistry Tsinghua University Beijing 100084 China

Directly coupling N 2 and CO 2 to synthesize urea by photocatalysis paves a sustainable route for urea synthesis, but its performance is limited by the competition of photogenerated electrons between N 2 and CO 2 , as well as the underutilized photogenerated holes. Herein, we report an efficient urea synthesis process involving photogenerated electrons and holes in respectively converting CO 2 and N 2 over a redox heterojunction consisting of WO 3 and Ni single-atom-decorated CdS (Ni 1 -CdS/WO 3 ). For the photocatalytic urea synthesis from N 2 and CO 2 in pure water, Ni 1 -CdS/WO 3 attained a urea yield rate of 78 μM h −1 and an apparent quantum yield of 0.15 % at 385 nm, which ranked among the best photocatalytic urea synthesis performance reported. Mechanistic studies reveal that the N 2 was converted into NO species by ⋅OH radicals generated from photogenerated holes over the WO 3 component, meanwhile, the CO 2 was transformed into *CO species over the Ni site by photogenerated electrons. The generated NO and *CO species were further coupled to form *OCNO intermediate, then gradually transformed into urea. This work emphasizes the importance of reasonably utilizing photogenerated holes in photocatalytic reduction reactions.

关键词： urea synthesis nitrogen carbon dioxide photogenerated holes Ni single atoms

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Fabrication-induced even-odd discrepancy of magnetotransport in few-layer MnBi2Te4

arXiv

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arXiv 2023年

作者： Li, Yaoxin Wang, Yongchao Lian, Zichen Li, Hao Gao, Zhiting Xu, Liangcai Wang, Huan Lu, Rui'e Li, Longfei Feng, Yang Zhu, Jinjiang Liu, Liangyang Wang, Yongqian Fu, Bohan Yang, Shuai Yang, Luyi Wang, Yihua Xia, Tianlong Liu, Chang Jia, Shuang Wu, Yang Zhang, Jinsong Wang, Yayu Liu, Chang State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China School of Materials Science and Engineering Tsinghua University Beijing100084 China Tsinghua-Foxconn Nanotechnology Research Center Department of Physics Tsinghua University Beijing100084 China Beijing Academy of Quantum Information Sciences Beijing100193 China Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices Department of Physics Renmin University of China Beijing100872 China Key Laboratory of Quantum State Construction and Manipulation Ministry of Education Renmin University of China Beijing100872 China School of Mechanical and Electric Engineering Guangzhou University Guangzhou510006 China International Center for Quantum Materials School of Physics Peking University Beijing100871 China State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai200433 China Frontier Science Center for Quantum Information Beijing100084 China Shanghai Research Center for Quantum Sciences Shanghai201315 China Shenzhen Institute for Quantum Science and Engineering Department of Physics Southern University of Science and Technology Shenzhen518055 China Interdisciplinary Institute of Light-Element Quantum Materials Research Center for Light-Element Advanced Materials Peking University Beijing100871 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing100190 China College of Math and Physics Beijing University of Chemical Technology Beijing100029 China Hefei National Laboratory Hefei230088 China

The van der Waals antiferromagnetic topological insulator MnBi2Te4 represents a promising platform for exploring the layer-dependent magnetism and topological states of matter. Recently observed discrepancies between magnetic and transport properties have aroused controversies concerning the topological nature of MnBi2Te4 in the ground state. In this article, we demonstrate that fabrication can induce mismatched even-odd layer dependent magnetotransport in few-layer MnBi2Te4. We perform a comprehensive study of the magnetotransport properties in 6- and 7-septuple-layer MnBi2Te4, and reveal that both even- and odd-number-layer device can show zero Hall plateau phenomena in zero magnetic field. Importantly, a statistical survey of the optical contrast in more than 200 MnBi2Te4 flakes reveals that the zero Hall plateau in odd-number-layer devices arises from the reduction of the effective thickness during the fabrication, a factor that was rarely noticed in previous studies of 2D materials. Our finding not only provides an explanation to the controversies regarding the discrepancy of the even-odd layer dependent magnetotransport in MnBi2Te4, but also highlights the critical issues concerning the fabrication and characterization of 2D material devices. Copyright © 2023, The Authors. All rights reserved.

关键词： Fabrication

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Flexible, High Scintillation Yield Cu3Cu2I5Film Made of Ball-Milled Powder for High Spatial Resolution X-Ray Imaging

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advanced Optical Materials 2022年第5期10卷

作者： Nan Li Ziwei Xu Yingrui Xiao Yucheng Liu Zhou Yang Shengzhong (Frank) Liu Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology Institute for Advanced Energy Materials and School of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China Dalian National Laboratory for Clean Energy and Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

Cu halide materials with low electronic dimension show great scintillation properties with high photoluminescence quantum yield (PLQY) and large Stokes shift, which can result in reabsorption-free scintillators. However, there is still a need for a large-scalable method to fabricate large amount of scintillation powder and large-size scintillation films. In this regard, a high scintillation yield Cu 3 Cu 2 I 5 −PDMS flexible film utilizing ball-milled Cu 3 Cu 2 I 5 powder is developed. The ball-milled Cu 3 Cu 2 I 5 powder shows a high PLQY of 74.5%, narrow emission peak of 80 nm and good ambient stability, demonstrating the potential of ball-milling method for large-scale scintillator production. Furthermore, the Cu 3 Cu 2 I 5 −PDMS film shows even high PLQY exceeding 90%, which may be ascribed to the passivation effect of PDMS resulting in a little longer carrier lifetime. The flexible Cu 3 Cu 2 I 5 −PDMS film can further deliver high spatial resolution of 6.8 lp mm −1 @0.2 MTF in X-ray imaging and good stability under steady X-ray illumination. This work demonstrates that the ball-milling method could be an effective approach for large-scale fabrication of low electronic dimensional scintillation materials.

关键词： scintillators ball-milling spatial resolution

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Spin excitations in the quantum dipolar magnet Yb(BaBO3)3

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Physical Review B 2022年第1期106卷 014409-014409页

作者： C. Y. Jiang Y. X. Yang Y. X. Gao Z. T. Wan Z. H. Zhu T. Shiroka C. S. Chen Q. Wu X. Li J. C. Jiao K. W. Chen Y. Bao Z. M. Tian L. Shu State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai 200438 China School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Wuhan 430074 People's Republic of China Laboratory for Muon-Spin Spectroscopy Paul Scherrer Institute CH-5232 Villigen PSI Switzerland Laboratorium für Festkörperphysik ETH Zürich CH-8093 Zürich Switzerland Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics (CAEP) Mianyang 621999 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Spallation Neutron Source Science Center Dongguan 523803 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China Shanghai Research Center for Quantum Sciences Shanghai 201315 China

We report results of magnetization, specific heat, and muon spin relaxation (μSR) measurements on single crystals of disorder-free Yb3+ triangular lattice Yb(BaBO3)3. The magnetization experiments show anisotropic magnetic properties with Curie-Weiss temperatures θ⊥=−1.40K (H⊥c) and θ∥=−1.16K (H∥c) determined from low-temperature data. The absence of both long-range antiferromagnetic order and spin freezing is confirmed down to 0.27 K at zero field. A two-level Schottky anomaly due to the opening of the ground-state Kramers doublet is observed from the low-temperature specific heat measurements when the applied magnetic fields μ0H>0.7T. At zero field, the increase of both Cmag/T and the muon spin relaxation rate λ below 1 K is due to the electronic spin excitations, which often exist in quantum magnets where dipole-dipole interactions create an anisotropy of magnetic properties. The spin excitation is also supported by the unusual maximum of the field dependence of λ due to the field-induced increase in the density of excitations. We argue that dipolar interaction is dominant and induces the spin dynamics in the quantum magnet Yb(BaBO3)3.

关键词： Antiferromagnetism Quantum spin liquid Spin dynamics Antiferromagnets Magnetic systems Magnetization measurements Muon spin relaxation & rotation Specific heat measurements

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Fine cubic Cu₂O nanocrystals as highly selective catalyst for propylene epoxidation with molecular oxygen (vol 12, 5921, 2021)

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NATURE COMMUNICATIONS 2021年第1期12卷 5921-5921页

作者： Xiong, Wei Gu, Xiang-Kui Zhang, Zhenhua Chai, Peng Zang, Yijing Yu, Zongyou Li, Dan Zhang, Hui Liu, Zhi Huang, Weixin Hefei National Laboratory for Physical Sciences at the Microscale Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes and Department of Chemical Physics University of Science and Technology of China 230026 Hefei People’s Republic of China School of Power and Mechanical Engineering Wuhan University 430072 Wuhan People’s Republic of China Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces Institute of Physical Chemistry Zhejiang Normal University 321004 Jinhua People’s Republic of China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 200050 Shanghai People’s Republic of China School of Physical Science and Technology ShanghaiTech University 201210 Shanghai People’s Republic of China Dalian National Laboratory for Clean Energy 116023 Dalian People’s Republic of China

Propylene epoxidation with O2 to propylene oxide is a very valuable reaction but remains as a long-standing challenge due to unavailable efficient catalysts with high selectivity. Herein, we successfully explore 27 nm-sized cubic Cu2O nanocrystals enclosed with {100} faces and {110} edges as a highly selective catalyst for propylene epoxidation with O2, which acquires propylene oxide selectivity of more than 80% at 90–110 °C. Propylene epoxidation with weakly-adsorbed O2 species at the {110} edge sites exhibits a low barrier and is the dominant reaction occurring at low reaction temperatures, leading to the high propylene oxide selectivity. Such a weakly-adsorbed O2 species is not stable at high reaction temperatures, and the surface lattice oxygen species becomes the active oxygen species to participate in propylene epoxidation to propylene oxide and propylene partial oxidation to acrolein at the {110} edge sites and propylene combustion to CO2 at the {100} face sites, which all exhibit high barriers and result in decreased propylene oxide selectivity. Direct propylene epoxidation with O2 to form propylene oxide (PO) selectively is a challenge. Here, the authors explore 27 nm-sized cubic Cu2O nanocrystals as thermocatalysts for this reaction which facilitate PO production with high selectivity, >80%, at moderate temperatures of 90–110 °C.

关键词： Catalytic mechanisms Heterogeneous catalysis Materials for energy and catalysis

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Effect of hot isostatic pressing (HIP) on microstructure and mechanical properties of Ti6Ai4V alloy fabricated by cold spray additive manufacturing

Effect of hot isostatic pressing (HIP) on microstructure and...

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International Thermal Spray Conference and Exposition: New Waves of Thermal Spray technology for Sustainable Growth, ITSC 2019

作者： Chen, Chaoyue Ren, Zhongming Xie, Yingchun Huang, Renzhong Liu, Min Yan, Xingchen Xie, Xinliang Liao, Hanlin State Key Laboratory of Advanced Special Steels School of Materials Science and Engineering Shanghai University Shanghai200444 China National Engineering Laboratory for Modern Materials Surface Engineering Technology Key Lab of Guangdong for Modern Surface Engineering Technology Guangdong Institute of New Materials Guangzhou510651 China ICB UMR 6303 CNRS Univ. Bourgogne Franche-Comté UTBM BelfortF-90010 France

ISBN: (纸本)9781510888005

The interior porous defects formed during the layer-by-layer fabrication process has attracted increasing attention for different additive manufacturing (AM) techniques and are regarded as a crucial factor affecting the all-round performance. In this work, aiming at the cold spray Ti6Al4V bulk materials, the hot isostatic pressing (HIP) is adopted to reduce the interior defects, adjust the microstructure and improve the mechanical properties. To characterize the pore morphologies and porosity evolution, the cold spray (CS) Ti6Al4V sample is characterized by optical microscope and X-ray computed tomography (XCT). Three-dimensional reconstructions by XCT show that the fully dense Ti6Al4V alloy can be obtained through the high temperature diffusion and high pressure compacting of HIP. After HIP treatment, the seriously deformed grains experienced an obvious growth with the uniformly distributed β precipitates around equiaxed α grains. The tensile test showed that the strength and ductility of CS Ti6Al4V alloys can be largely improved by the enhanced diffusion and resultant metallurgical bonding. With the HIP treatment, the CS samples exhibit highly densified morphology and adjusted microstructure that can benefit the improvement of mechanical properties. © 2019 ASM International. All rights reserved.

关键词： Hot isostatic pressing

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Numerical simulation for the investment casting process of a large-size titanium alloy thin-wall casing

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Progress in Natural Science:Materials International 2018年第4期28卷 520-528页

作者： Pan Tao Heng Shao Zhijun Ji Hai Nan Qingyan Xu Key Laboratory for Advanced Materials Processing Technology Ministry of Education School of Materials Science and Engineering Tsinghua University Beijing Institute of Aeronautical Materials

To optimize the investment casting process when producing high quality large-size titanium alloy thin-wall components is a time-consuming job due to the complicated metallurgical process. Numerical simulation is a high-efficiency method compared with trial and error, and therefore is introduced to the investment casting process optimization to shorten the new product development cycle and reduce the production cost. In this study, weakly compressible model(WCM) and ununiformed finite difference mesh(UFDM) was developed to reduce the memory consumption and ensure the simulation efficiency. The precision of the WCM and UFDM were verified by numerical simulation of cavity heat convection in a square cavity and hydraulics simulation of centrifugal filling in a transparent cavity. The numerical simulation of the investment casting process of a titanium alloy thin-wall casing under different process conditions was accomplished using a self-developed software, and the distribution characteristics of potential shrinkage defects were predicted. It was found that the predicted defects in the titanium alloy casing matched well with the actual X-ray experimental results. For the components investigated in this paper, more numerical simulation results show that the centrifugal casting process with respect to gravity casting had no obvious improvements in the concentrated shrinkage defects, and the gravity casting process can be more reasonable from the engineering point of view.

关键词： Titanium alloy Investment casting Numerical simulation Finite difference method Non-uniform mesh

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Heat transport in herbertsmithite: Can a quantum spin liquid survive disorder?

arXiv

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arXiv 2021年

作者： Huang, Y.Y. Xu, Y. Wang, Le Zhao, C.C. Tu, C.P. Ni, J.M. Wang, L.S. Pan, B.L. Fu, Ying Hao, Zhanyang Liu, Cai Mei, Jia-Wei Li, Shiyan Y. State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai200438 China School of Physics and Electronic Science East China Normal University Shanghai200241 China Shenzhen Institute for Quantum Science and Engineering Department of Physics Southern University of Science and Technology Shenzhen518055 China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and Technology Shenzhen518055 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China Shanghai Research Center for Quantum Sciences Shanghai201315 China

Arguably the most favorable situation for spins to enter the long-sought quantum spin liquid (QSL) state is when they sit on a kagome lattice. No consensus has been reached in theory regarding the true ground state of this promising platform. The experimental efforts, relying mostly on one archetypal material ZnCu3(OH)6C12, have also led to diverse possibilities. Apart from subtle interactions in the Hamiltonian, there is the additional degree of complexity associated with disorder in the real material ZnCu3(OH)6C12that haunts most experimental probes. Here we resort to heat transport measurement, a cleaner probe in which instead of contributing directly, the disorder only impacts the signal from the kagome spins. For ZnCu3(OH)6C12and a related QSL candidate Cu3Zn(OH)6FBr, we observed no contribution by any spin excitation nor any field-induced change to the thermal conductivity. These results impose different constraints on various scenarios about the ground state of these two kagome compounds: while a gapped QSL, or certain quantum paramagnetic state other than a QSL, is compatible with our results, a gapless QSL must be dramatically modified by the disorder so that gapless spin excitations are localized. Copyright © 2021, The Authors. All rights reserved.

关键词： Ground state

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