检索结果-内蒙古大学图书馆

Journal of Materiomics 2019年第2期5卷 185-194页

作者： Ruiping Liu Zirui Wu Peng He Haoyu Fan Zeya Huang Lei Zhang Xinshuang Chang Hang Liu Chang-an Wang Yutao Li Department of Materials Science and Engineering China University of Mining&Technology(Beijing)Beijing 100083China School of Materials Science and Engineering State Key Laboratory of New Ceramics and Fine ProcessingTsinghua UniversityBeijing 100084China Department of Mechanical Engineering University of Alaska FairbanksFairbanksAK 99775United States Materials Science and Engineering Program and Texas Materials Institute The University of Texas at AustinTexas78712United States

A self-standing,flexible and lithium dendrite growth-suppressing composite gel polymer electrolyte membrane was designed for the use of room-temperature lithium ion *** multi-functional composite semi-interpenetrating polymer network(referred to as“Cs-IPN”)electrolyte membrane was fabricated by combining a UV-cured ethoxylated trimethylolpropane triacrylate(ETPTA)macromer with alumina nanoparticles in the presence of liquid electrolyte and thermoplastic linear poly(ethylene oxide)(PEO).The polymer electrolyte membrane exhibits a semi-interpenetrating polymer network structure and a higher room temperature ionic conductivity,which impart the electrolyte with a significant cycling(120 mAh g^(-1)after 200 cycles)and a remarkable rate(137 mAh g^(-1)at 0.1℃,130 mAh g^(-1)at 0.5℃,119 mAh g^(-1)at 1℃ and 100 mAh g^(-1)at 2℃)performance in Li/LiFePO4 *** importantly,the polymer electrolyte possesses superior ability to inhibit the growth of lithium dendrites,which makes it promising for next generation lithium ion batteries.

关键词： Gel polymer electrolytes Semi-interpenetrating polymer network UV-Cured reaction Ionic conductivity Lithium ion batteries

Dependence of adhesive friction on surface roughness and elastic modulus

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Maksuta, Daniel Dalvi, Siddhesh Gujrati, Abhijeet Pastewka, Lars Jacobs, Tevis D.B. Dhinojwala, Ali Department of Biology Integrated Bioscience Program The University of Akron AkronOH44325 United States School of Polymer Science and Polymer Engineering The University of Akron AkronOH44325 United States Department of Mechanical Engineering and Materials Science University of Pittsburgh PittsburghPA15261 United States Department of Microsystems Engineering University of Freiburg Freiburg79110 Germany

When adhesive elastomeric materials slide over hard rough surfaces at low velocities, there are two primary dissipative mechanisms that control how friction changes with sliding velocity: viscoelastic dissipation and adhesive dissipation. To distinguish the contribution of these dissipative mechanisms we have measured frictional shear stresses for crosslinked polydimethylsiloxane (PDMS) on three different rough surfaces of similar surface chemistry across nearly six decades of sliding velocity. The results show that the observed friction is dominated by adhesive dissipation, rather than viscoelastic dissipation. Prior models for elastomer friction assume that roughness only influences adhesive dissipation via the amount of contact area;by contrast, we find that the roughness-induced oscillations occurring across all length scales from macroscopic to atomic influence the molecular processes governing the adhesive dissipation. While it was previously known that roughness-induced oscillations affected the viscoelastic dissipation;this is the first demonstration that these oscillations also control the behavior of the adhesive component of friction. Finally, while theory predicts that rough friction should be independent of elastic modulus, we show that a strong dependence on modulus, with the frictional shear stress scaling as E’1/2. When analyzed in this way, data from four different moduli and three different roughnesses collapse onto a universal curve to describe the velocity-dependent friction of soft materials. Taken together, this investigation sheds new light on the adhesive component of friction, and how it depends on the roughness and stiffness of the materials. © 2021, CC BY-NC-SA.

关键词： Surface roughness

Understanding the Durability of Nanocatalysts in Energy Conversion by Advanced Electron Microscopy

学校读者我要写书评

暂无评论

Microscopy and Microanalysis 2024年第SUPPLEMENT_1期30卷

作者： Ferreira, Paulo INL – International Iberian Nanotechnology Laboratory Braga Portugal Materials Science and Engineering Program The University of Texas at Austin Austin Texas United States Mechanical Engineering Department and IDMEC Instituto Superior Técnico University of Lisbon Lisboa Portugal

Inter-Site Distance Effect in Electrocatalysis

学校读者我要写书评

暂无评论

Angewandte Chemie 2025年

作者： Jiongcan Xiang Pengfei Wang Panpan Li Min Zhou Guihua Yu Zhaoyu Jin Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu 611731 China College of Materials Science and Engineering Sichuan University Chengdu 610065 China State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China Materials Science and Engineering Program and Walker Department of Mechanical Engineering the University of Texas at Austin Austin TX 78712 USA

The inter-site distance effect (ISDE) has gained significant attention in heterogeneous catalysis, challenging classical models that treat adjacent nonbonded sites as isolated. Recent studies demonstrate that these sites can exhibit long-range cooperative interactions, enhancing reaction efficiencies. Fully leveraging the ISDE to overcome limitations in site reactivity requires a multidisciplinary approach and advanced techniques. This review provides a comprehensive overview of ISDE in electrocatalysis, starting with strategies for synthesizing materials with tunable inter-site distances. It examines ISDE across various catalyst models, including monometallic and heteronuclear atomic sites, active sites within clusters, and the lattice of nanocatalysts, focusing on their electronic structures, spatial geometries, and synergistic interactions. Advanced characterization and computational methods are highlighted as essential for identifying inter-site structures and distances, providing a systematic framework for understanding ISDE's role in electrocatalysis. The review also proposes best practices for studying ISDE, addressing current challenges and offering future perspectives. These insights aim to inform the design of highly efficient catalysts, enhance the understanding of catalytic mechanisms, and contribute to the development of more efficient energy conversion technologies, providing a foundation for further research into optimizing electrocatalysts.

关键词： Electrocatalysis Inter-site distance Single-atom catalysts Site density

Characterizing the mechanical response of metallic glasses to uniaxial tension using a spring network model

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Nawano, Aya Schroers, Jan Shattuck, Mark D. O’Hern, Corey S. Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

Metallic glasses are frequently used as structural materials. Therefore, it is important to develop methods to predict their mechanical response as a function of the microstructure prior to loading. We develop a novel coarse-grained spring network model, which describes the mechanical response of metallic glasses using an equivalent series network of springs, which can break and re-form to mimic atomic rearrangements during deformation. To validate the spring network model, we perform numerical simulations of quasistatic, uniaxial tensile deformation of Lennard-Jones and embedded atom method (EAM) potentials for Cu50Zr50 metallic glasses in the absence of large-scale shear band formation. We consider samples prepared using a wide range of cooling rates and with different amounts of crystalline order. We show that both the Lennard-Jones and EAM models possess qualitatively similar stress σ versus strain γ curves. By specifying five parameters in the spring network model (ultimate strength, strain at ultimate strength, slopes of σ(γ) at γ = 0 and at large strain, and strain at fracture where σ = 0), we can accurately describe the form of the stress-strain curves during uniaxial tension for the computational studies of Cu50Zr50, as well as recent experimental studies of several Zr-based metallic glasses. For the computational studies of Cu50Zr50, we find that the yield strain distribution is shifted to larger strains for slowly cooled glasses compared to rapidly cooled glasses. In addition, the average number of new springs and their rate of formation decreases with decreasing cooling rate. These effects offset each other at large strains, causing the stress-strain curve to become independent of the sample preparation protocol in this regime. In future studies, we will extract the parameters that define the spring network model directly from atomic rearrangements that occur during uniaxial deformation. © 2023, CC BY-NC-ND.

关键词： Metallic glass

Detection of Toxic Contaminants in Alcohol-Based Hand Sanitizers Using Infrared Spectroscopy

学校读者我要写书评

暂无评论

Applied Spectroscopy Practica

Applied Spectroscopy Practica 2023年第2期1卷

作者： Aminur Rashid Chowdhury Umar Burney David King Tse-Ang Lee Dan Hutter Tanya Hutter Department of Mechanical Engineering The University of Texas at Austin Austin Texas USAMaterials Science and Engineering Program and Texas Materials Institute The University of Texas at Austin Austin Texas USA Department of Mechanical Engineering The University of Texas at Austin Austin Texas USA Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas USA

Recent fatalities due to methanol and 1-propanol toxicity in alcohol-based hand sanitizers has led the U.S. Food and Drug Administration (FDA) to ban 594 different hand sanitizer brands. The FDA also introduced methanol testing in alcohol-based hand sanitizers before allowing the products to enter the United States This requirement creates a need for inexpensive, rapid, and portable testing methods to measure methanol and 1-propanol concentrations in alcohol-based hand sanitizers. Here we study the performance of infrared (IR) spectroscopy for measuring methanol and 1-propanol concentrations in an alcohol-based hand sanitizer, and compare the performance of two portable spectrometers, Texas Instruments near-infrared (NIR) spectrometer (TI NIR) and NeoSpectra mid-infrared (MIR) spectrometer. The IR absorbance spectra were measured in transmission mode at different path lengths for 52 different hand sanitizer samples spiked with 0%–1% v/v concentrations of methanol and 1-propanol. A partial least-squares regression analysis shows ability to detect contaminant concentrations with a correlation coefficient of determination (r2) up to 0.99 and root mean square error of prediction as low as 0.34% v/v.

关键词： Hand sanitizers toxins methanol 1-propanol infrared spectroscopy partial least-squares regression PLSR

Linear Dielectric Thermodynamics: A New Universal Law for Optical, Dielectric Constants

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Burns, S.J. Materials Science Program Department of Mechanical Engineering University of Rochester RochesterNY14627 United States

Linear dielectric thermodynamics are formally developed to explore the isothermal and adiabatic temperature - pressure dependence of dielectric constants. The refractive index of optical materials is widely measured in the literature: it is both temperature and pressure dependent. The argument to establish the dielectric constant’s isentropic temperature dependence is a thermodynamic one and is thus applicable to all physical models that describe electron clouds and electronic resonances within materials. The isentropic slope of the displacement field versus the electric field at all temperatures is described by an adiabatic dielectric constant in an energy-per-unit mass system. This slope is shown through the electronic part of the entropy to be unstable at high temperatures due to the change in the curvature of the temperature dependence of the dielectric constant. The electronic entropy contribution for optical, thermo-electro materials has negative heat capacities which are unacceptable. The dielectric constant’s temperature and pressure dependence is predicted to be only dependent on the specific volume so isentropes are always positive. A new universal form for the dielectric constant follows from this hypothesis: the dielectric constant is proportional to the square root of the specific volume. Copyright © 2020, The Authors. All rights reserved.

关键词： Refractive index

Erratum: Perspective—Mass Conservation in Models for Electrodeposition/Stripping in Lithium Metal Batteries [ J. Electrochem. Soc., 168, 092502 (2021)]

学校读者我要写书评

暂无评论

Journal of The Electrochemical Society 2022年第5期169卷 059002-059002页

作者： Lubhani Mishra Venkat R. Subramanian Walker Department of Mechanical Engineering and Materials Science and Engineering Program Texas Materials Institute The University of Texas at Austin Austin Texas 78712 United States of America

Light-driven C-H activation mediated by 2D transition metal dichalcogenides

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Li, Jingang Zhang, Di Guo, Zhongyuan Jiang, Xi Larson, Jonathan M. Zhu, Haoyue Zhang, Tianyi Gu, Yuqian Blankenship, Brian Chen, Min Wu, Zilong Huang, Suichu Kostecki, Robert Minor, Andrew M. Grigoropoulos, Costas P. Akinwande, Deji Terrones, Mauricio Redwing, Joan M. Li, Hao Zheng, Yuebing Materials Science & Engineering Program Texas Materials Institute Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States Laser Thermal Laboratory Department of Mechanical Engineering University of California BerkeleyCA94720 United States Tohoku University Sendai980-8577 Japan Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Chemistry and Biochemistry Baylor University WacoTX76798 United States Department of Materials Science and Engineering The Pennsylvania State University University ParkPA16802 United States Chandra Family Department of Electrical & Computer Engineering The University of Texas at Austin AustinTX78712 United States Department of Materials Science and Engineering University of California BerkeleyCA94720 United States Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States National Center for Electron Microscopy Molecular Foundry Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Center for Two-Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States Department of Physics Department of Chemistry The Pennsylvania State University University ParkPA16802 United States 2D Crystal Consortium Materials Research Institute The Pennsylvania State University University ParkPA16802 United States

C-H bond activation enables the facile synthesis of new chemicals. While C-H activation in short-chain alkanes has been widely investigated, it remains largely unexplored for long-chain organic molecules. Here, we report light-driven C-H activation in complex organic materials mediated by 2D transition metal dichalcogenides (TMDCs) and the resultant solid-state synthesis of luminescent carbon dots in a spatially-resolved fashion. We unravel the efficient H adsorption and a lowered energy barrier of C-C coupling mediated by 2D TMDCs to promote C-H activation. Our results shed light on 2D materials for C-H activation in organic compounds for applications in organic chemistry, environmental remediation, and photonic materials. © 2022, CC BY-NC-SA.

关键词： Chemical activation

3D-printed micro-pore evaporator for increasing concentration of analytes in aqueous solutions

学校读者我要写书评

暂无评论

Lab on a chip 2025年 2025 May 27页

作者： Yufeng Su Tanya Hutter Walker Department of Mechanical Engineering The University of Texas at Austin Austin TX 78712 USA. tanya.hutter@utexas.edu. Materials Science and Engineering Program and Texas Material Institute The University of Texas at Austin Austin TX 78712 USA.

To address the detection limit challenges of analytical instruments at low concentrations, this study explores the development of a concentrator, fabricated micro-3D printing technology, relying on solvent evaporation through micro-pores. The operating temperature can be as low as room temperature, allowing for compatibility with biomolecules that are sensitive to high temperatures. Moreover, the device is suitable for processing small sample volumes ranging from hundreds to tens of microliters. There are three designs of the hydrophilic biocompatible polymer tube, each featuring micro-pores with diameters of 30, 50 and 70 μm, spaced at distances of 150, 250 and 350 μm, respectively. All designs have the same total length of 16 mm and identical contact surface area. The tube is surrounded by an outer tube for a sweeping gas at a flow between 20 and 100 mL min for evaporation rate control. Theoretical calculations and experimental data were used to quantify device's performance and capabilities. Experiments conducted with deionized water and with aqueous glucose solutions demonstrate the device's capability to achieve up to a 10-fold concentration increase. The study also addresses potential issues such as analyte loss and the influence of various parameters like sweeping gas flow rates and liquid feeding rates on the concentration process. This work demonstrates the potential of the micro-3D printed device as a reliable and efficient method for sample concentration, critical for enhancing detection sensitivities for various applications such as bioassays and biosensors.

关键词： Bioassay