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arXiv 2021年

作者： Ortiz, Víctor H. Gomez, Michael J. Liu, Yawen Aldosary, Mohammed Shi, Jing Wilson, Richard B. Department of Mechanical Engineering and Materials Science and Engineering Program University of California RiversideCA92521 United States Department of Physics and Astronomy Program University of California RiversideCA92521 United States

We investigate picosecond spin-currents across Au/iron-garnet interfaces in response to ultrafast laser heating of the electrons in the Au film. In the picoseconds after optical heating, interfacial spin currents occur due to an interfacial temperature difference between electrons in the metal and magnons in the insulator. We report measurements of this interfacial longitudinal spin Seebeck effect between Au and rare-earth iron-garnet insulators, i.e. RE3Fe5O12, where RE is Y, Eu, Tb, Tm. By systematically varying the rare-earth element, we modify the total magnetic moment of the iron-garnet. We use time domain thermoreflectance (TDTR) measurements to characterize the thermal response of the bilayer to ultrafast optical heating. We use time-resolved magneto-optic Kerr effect (TR-MOKE) measurements of the Au layer to measure the time-evolution of spin accumulation in the Au film. Replacing Y with other rare-earths enhances the electron-magnon conductance Ge-m at the Au iron-garnet interface by as much as a factor of three. The electron-magnon conductance does not follow the trend of either the total magnetization of the iron garnet or the magnetic moment of the rare-earth. © 2021, CC BY.

关键词： Electrons

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Stepwise construction of Pt decorated oxygen-deficient mesoporous titania microspheres with core-shell structure and magnetic separability for efficient visible-light photocatalysis

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Chinese Chemical Letters 2020年第6期31卷 1598-1602页

作者： Zhijian Li Yao Wang Ahmed A.Elzatahry Xuanyu Yang Shouzhi Pu Wei Luo Xiaowei Cheng Yonghui Deng Department of Chemistry State Key Laboratory of Molecular Engineering of PolymersShanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsiChEMFudan University.Shanghai 200433China Jiangxi Key Laboratory of Organic Chemistry Jiangxi Science and Technology Normal UniversityNanchang 330013China Materials Science and Technology Program College of Arts and SciencesQatar UniversityDoha PO Box 2713Qatar State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China

Solid photocatalysts with high specific surface area,superior photoactivity and ease of recycling are highly desired in chemical process,water treatment and so *** this study,a facile stepwise sol-gel coating approach was utilized to synthesize Pt decorated oxygen-deficient mesoporous titania microspheres with core-shell structure and convenient magnetic separability(denoted as Fe3 O4@-SiO2@Pt/mTiO2-x).These photocatalysts consist of magnetic Fe3 O4 cores,nonporous insulating SiO2 middle layer and mesoporous anatase TiO2-x shell decorated by Pt nanoparticles(~3.5 nm)through wet impregnation and H2 *** a result of high activity of oxygen-deficiency of black TiO2-x by H2 reduction and efficient inhibition of electron-hole recombination by Pt nanoparticles,the rationally designed core-shell Fe3 O4@SiO2@Pt/mTiO2-x photocatalysts exhibit superior photocatalytic performance in rhodamine B(RhB)degradation under visible light irradiation,with more than 98%of RhB degraded within 50 *** core-shell structured photocatalysts show excellent recyclability under the assistance of magnetic separation with well-retained photocatalytic performance even after running five *** stepwise synthesis method paves the way for the rational design of a high-efficiency recyclable heterogeneous catalyst,including photocatalysts,for various applications.

关键词： Core-shell Mesoporous TiO2 Photocatalytic activity Magnetic recovery Visible light

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Brachiation of a polymer chain in the presence of a dynamic network

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Physical Review E 2020年第2期102卷 020501(R)-020501(R)页

作者： Pamela C. Cai Brad A. Krajina Andrew J. Spakowitz Department of Chemical Engineering Stanford University Stanford California 94305 USA Department of Materials Science Stanford University Stanford California 94305 USA Department of Applied Physics Stanford University Stanford California 94305 USA Biophysics Program Stanford University Stanford California 94305 USA

The viscoelastic behavior of a physically crosslinked gel involves a spectrum of molecular relaxation processes, which at the single-chain level involve the chain undergoing transient hand-to-hand motion through the network. We develop a self-consistent theory for describing transiently associating polymer solutions that captures these complex dynamics. A single polymer chain transiently binds to a viscoelastic background that represents the polymer network formed by surrounding polymer chains. The viscoelastic background is described in the equation of motion as a memory kernel, which is self-consistently determined based on the predicted rheological behavior from the chain itself. The solution to the memory kernel is translated into rheological predictions of the complex modulus over a wide range of frequencies to capture the time-dependent behavior of a physical gel. Using the loss tangent predictions, a phase diagram is shown for the sol-gel transition of polymers with dynamic association affinities. This theory provides a predictive, molecular-level framework for the design of associating gels and supramolecular assemblies with targeted rheological properties.

关键词： Polymer gels Rheological properties Viscoelasticity Polymer theory

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Processing of Wc with Fe-Based Alternative Binders: Adjustment of C Content and Effect of Cr Addition

SSRN

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SSRN 2023年

作者： de Nicolás-Morillas, María Beshratloo, Hossein Cabezas, Laura de la Mata, María Sales, David L. Pereira, Leonel Müller-Grunz, Andrea Bertalan, Claudio Useldinger, Ralph Llanes, Luis Gordo, Elena GTP Department of Materials Science and Engineering IAAB Universidad Carlos III de Madrid Leganés Madrid28911 Spain Sustainable Powder Technologies – IMDEA Materials Institute Getafe Madrid28906 Spain CIEFMA Department of Materials Science and Metallurgical Engineering Universitat Politècnica de Catalunya - BarcelonaTech Barcelona08019 Spain Institute of Ceramic and Glass- CSIC Madrid28049 Spain Barcelona Research Center in Multiscale Science and Engineering Universitat Politècnica de Catalunya – BarcelonaTech Barcelona08019 Spain INNANOMAT Departamento de Ciencia de los Materiales I. M. y Q. I IMEYMAT Universidad de Cádiz Puerto Real Cádiz11510 Spain CERATIZIT Luxembourg S. à r. l. Mamer8232 Luxembourg

Alternative hard materials to traditional WC-Co are one of the main goals in the investigation efforts of both scientific and industrial communities. In this investigation, WC-based materials were designed and processed with different Fe alloys employing a powder metallurgy route. Two candidates were selected: FeCrAl and FeNiCr. The former showed the formation of aluminium oxides, which hindered a homogeneous metal-ceramic distribution. On the other hand, FeNiCr led to dense and optimised samples which were further characterised in terms of their mechanical properties and corrosion resistance. They revealed an excellent combination of hardness and toughness, comparable or even superior to industrial compositions containing Co. Selected Cr addition induced some segregation and formation of secondary carbides –as evidenced by optical microscopy, XRD and TEM analyses– with a decrease in the TRS value. However, massive nanoindentation tests revealed that it also led to improved intrinsic hardness of binder and composite (metal-ceramic) phases, as well as enhanced corrosion resistance in acidic media compared to Cr-free alternative and reference hardmetals. © 2023, The Authors. All rights reserved.

关键词： Corrosion resistance

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Self-sustained eversion or inversion of a thermally responsive torus

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Physical Review E 2021年第3期103卷 033004-033004页

作者： Kai Li Zengfu Chen Zhijian Wang Shengqiang Cai Department of Civil Engineering Anhui Jianzhu University Hefei Anhui 230601 China Materials Science and Engineering Program University of California San Diego La Jolla California 92093 USA Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla California 92093 USA

When a cylindrical rod is placed on a flat and hot surface with a constant temperature, it can reach a steady state after certain time. In the steady state, though the temperature field inside the rod is inhomogeneous, it does not change with time. The inhomogeneous temperature change in the rod may induce inhomogeneous thermal expansion in it. Recent experiments have determined that if the rod is slightly curved, the inhomogeneous thermal expansion in the rod can drive its continuous and self-sustained rolling on a hot surface. It has been further shown that if the rod is bent to a closed torus and placed on a hot surface, the torus everts or inverts continuously due to the cross-coupling between the thermal field and the cyclic rotation. Such cyclic eversion or inversion of a torus can be regarded as a zero-elastic-energy mode because both the elastic energy and the shape of the torus remain unchanged during the rotation. In this article, we develop a coupled mechanics theory to model the continuous self-sustained eversion or inversion of a viscoelastic torus on a hot surface. We hope our modeling will inspire more novel designs of elastic motors being capable of zero-energy mode motion and help to quantitatively predict their performance.

关键词： Continuum mechanics Elasticity Mechanical deformation

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Controllable directional excitation and emission of nanoemitters by a subwavelength mie antenna

Controllable directional excitation and emission of nanoemit...

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2020 Frontiers in Optics Conference, FiO 2020

作者： Fang, Jie Wang, Mingsong Yao, Kan Zheng, Yuebing Materials Science and Engineering Program Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States

ISBN: (纸本)9781943580804

We derive a universal multipolar model for dipole-sphere hybrids, introduce single subwavelength silicon nanospheres at visible wavelengths with facile size control, and demonstrate controllable directional excitation and emission of nanoemitters (e.g. WS2, MoS2) for on-demand emission property modulations. © OSA 2020 © 2020 The Author(s)

关键词： Nanospheres

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Two-step electronic response to magnetic ordering in a van der Waals ferromagnet

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Physical Review B 2024年第4期109卷 045416-045416页

作者： Han Wu Jian-Xin Zhu Lebing Chen Matthew W. Butcher Ziqin Yue Dongsheng Yuan Yu He Ji Seop Oh Bin Gao Jianwei Huang Shan Wu Cheng Gong Yucheng Guo Sung-Kwan Mo Jonathan Denlinger Donghui Lu Makoto Hashimoto Matthew B. Stone Alexander I. Kolesnikov Songxue Chi Junichiro Kono Andriy H. Nevidomskyy Robert J. Birgeneau Pengcheng Dai Ming Yi Department of Physics and Astronomy and Rice Center for Quantum Materials Rice University Houston Texas 77005 USA Theoretical Division Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Center for Integrated Nanotechnologies Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Department of Physics University of California at Berkeley Berkeley California 94720 USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas 77005 USA Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan Department of Applied Physics Yale University New Haven Connecticut 06511 USA Department of Electrical and Computer Engineering and Quantum Technology Center University of Maryland College Park Maryland 20742 USA Advanced Light Source Lawrence Berkeley National Laboratory Berkeley California 94720 USA Stanford Synchrotron Radiation Lightsource SLAC National Accelerator Laboratory Menlo Park California 94025 USA Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Electrical and Computer Engineering Rice University Houston Texas 77005 USA Smalley-Curl Institute Rice University Houston Texas 77005 USA Department of Material Science and Nanoengineering Rice University Houston Texas 77005 USA Department of Materials Science and Engineering University of California Berkeley California 94720 USA

The two-dimensional material Cr2Ge2Te6 is a member of the class of insulating van der Waals (vdW) magnets. Here, using high resolution angle-resolved photoemission spectroscopy in a detailed temperature dependence study, we identify a clear response of the electronic structure to a dimensional crossover in the form of two distinct temperature scales marking onsets of modifications in the electronic structure. Specifically, we observe Te p-orbital-dominated bands to undergo changes at the Curie transition temperature TC while the Cr d-orbital-dominated bands begin evolving at a higher temperature scale. Combined with neutron scattering, density functional theory calculations, and Monte Carlo simulations, we find that the electronic system can be consistently understood to respond sequentially to the distinct temperatures at which in-plane and out-of-plane spin correlations exceed a characteristic length scale. Our findings reveal the sensitivity of the orbital-selective electronic structure for probing the dynamical evolution of local moment correlations in vdW insulating magnets.

关键词： Electronic structure Magnetic order Magnetic phase transitions Van der Waals systems Angle-resolved photoemission spectroscopy

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Effect of dual modification on structural, functional and dielectric properties of cassava starch

Food Physics

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Food Physics 2025年 2卷

作者： Cremasco, Paula Figueiredo M. Siqueira, Karine Mayuri Pistoni Sobral, Paulo José do Amaral Velloso, Walter Ferreira de Lima, César Gonçalves Gut, Jorge Andrey Wilhelms Moraes, Izabel Cristina Freitas Postgraduate Program in Materials Science and Engineering Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Department of Biossistems Engineering Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Department of Food Engineering Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Food Research Center (FoRC) University of São Paulo Lake Street São Paulo São Paulo 05508-080 Brazil Departament of Basic Sciences Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Department of Chemical Engineering Polytechnic School University of São Paulo Lake Street São Paulo São Paulo 05508-080 Brazil

The combined effect of hydrocolloid addition and microwave heating on the structural, physical and functional properties of cassava starch remains underexplored, despite individual studies on these modification methods. The dielectric properties, important for the microwave treatment of starch, have received little attention in recent studies. Cassava starch with and without addition of hydrocolloids (guar and xanthan gums) was modified by microwave heating for two different exposure times, and its structural, functional, and dielectric properties were studied. The dual modification enhanced the swelling power and oil holding capacity of the starch, reduced its gelatinization temperature, and did not alter its crystallinity. Notably, xanthan-modified starch microwaved for 6 min exhibited higher color variation (ΔE*) and increased granules agglomeration, while the microwave treatment alone roughened the surface of the starch granules. The mean diameters D[4,3] of starch increased with xanthan gum addition, microwave treatment (6 min), and their combination. The relative permittivity (ε’), loss factor (ε”) and penetration depth (D_p) were lower for samples modified by the combined method. Considering the type of hydrocolloid and the microwave exposure time, the combined modification significantly influenced the properties of starch, offering a promising approach to producing starch with enhanced functional properties. © 2024 KeAi Communications Co., Ltd

关键词： Biopolymers Cassava starch Guar Microwave Xanthan

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Detecting diabetes-induced abnormal chirality in urine via accumulation-assisted plasmonic chiral sensing

Detecting diabetes-induced abnormal chirality in urine via a...

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2020 Frontiers in Optics Conference, FiO 2020

作者： Liu, Yaoran Wu, Zilong Zheng, Yuebing Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program Texas Materials Institute The University of Texas at Austin AustinTX78712 United States

We demonstrate the label-free chiral detection of metabolic molecules in urine via accumulation-assisted plasmonic chiral sensing, which will benefit the development of point-of-care devices for first-line noninvasive... 详细信息

ISBN: (纸本)9781943580804

关键词： Stereochemistry

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Machine Learning Moment Tensor Potential for Modelling Dislocation and Fracture in L10-TiAl and D019-Ti3Al Alloys

arXiv

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arXiv 2023年

作者： Qi, Ji Aitken, Z.H. Pei, Qingxiang Tan, Anne Marie Z. Zuo, Yunxing Jhon, M.H. Quek, S.S. Wen, T. Wu, Zhaoxuan Ong, Shyue Ping Materials Science and Engineering Program University of California San Diego 9500 Gilman Dr Mail Code 0448 La Jolla CA92093-0448 United States 1 Fusionopolis Way Connexis #16-16 Singapore138632 Singapore Department of NanoEngineering University of California San Diego 9500 Gilman Dr Mail Code 0448 La Jolla CA92093-0448 United States Department of Mechanical Engineering The University of Hong Kong Hong Kong Department of Materials Science and Engineering City University of Hong Kong Hong Kong Hong Kong Institute for Advanced Study City University of Hong Kong Hong Kong

Dual-phase γ-TiAl and α2-Ti3Al alloys exhibit high strength and creep resistance at high temperatures. However, they suffer from low tensile ductility and fracture toughness at room temperature. Experimental studies show unusual plastic behaviour associated with ordinary and superdislocations, making it necessary to gain a detailed understanding on their core properties in individual phases and at the two-phase interfaces. Unfortunately, extended superdislocation cores are widely dissociated beyond the length scales practical for routine first-principles density-functional theory (DFT) calculations, while extant interatomic potentials are not quantitatively accurate to reveal mechanistic origins of the unusual core-related behaviour in either phases. Here, we develop a highly-accurate moment tensor potential (MTP) for the binary Ti-Al alloy system using a DFT dataset covering a broad range of intermetallic and solid solution structures. The optimized MTP is rigorously benchmarked against both previous and new DFT calculations, and unlike existing potentials, is shown to possess outstanding accuracy in nearly all tested mechanical properties, including lattice parameters, elastic constants, surface energies, and generalized stacking fault energies (GSFE) in both phases. The utility of the MTP is further demonstrated by producing dislocation core structures largely consistent with expectations from DFT-GSFE and experimental observations. The new MTP opens the path to realistic modelling and simulations of bulk lattice and defect properties relevant to the plastic deformation and fracture processes in γ-TiAl and α2-Ti3Al dual-phase alloys. © 2023, CC BY.

关键词： Aluminum alloys

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