检索结果-内蒙古大学图书馆

arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

来源：评论

学校读者我要写书评

暂无评论

Defect-driven relaxation of nanostructured Cu examined by in situ heating high-energy synchrotron X-ray microbeam diffraction

引用

Journal of Alloys and Compounds 2025年 1028卷

作者： Lee, Isshu Bhatta, Laxman Xu, Donghua Blankenburg, Malte Lienert, Ulrich Liss, Klaus-Dieter Kawasaki, Megumi Materials Science Program Oregon State University CorvallisOR97331 United States School of Mechanical Industrial and Manufacturing Engineering Oregon State University CorvallisOR97331 United States Hamburg22607 Germany University of Tennessee Oak Ridge Innovation Institute KnoxvilleTN37996 United States

Bulk nanostructured metals introduced by severe plastic deformation contain an excess of lattice defects. A nanostructured copper (Cu) processed by a high-pressure torsion technique was examined during in situ heating to investigate microstructural relaxation and quantify the evolution of microstructural parameters using high-energy synchrotron microbeam X-ray diffraction. While general microstructural relaxations, such as recovery, recrystallization, and subsequent grain growth, were observed, the key microstructural parameters, including grain size, microstrain, dislocation density, and thermal expansion coefficient, and their changes at critical temperatures were uniquely described and quantified through diffraction data. Based on this analysis, the stored energies driving thermally activated microstructural changes were estimated for individual defect types — grain boundaries, dislocations, and vacancies — that are expected to significantly influence the relaxation behavior of nanostructured Cu. This study demonstrates the effectiveness of diffraction characterization techniques for gaining a comprehensive understanding of the thermal stability of bulk nanostructured materials. © 2025 Elsevier B.V.

关键词： Dislocations (crystals)

来源：评论

学校读者我要写书评

暂无评论

High-Performance Silicon Anodes Enabled by Multifunctional Ultrafine Silica Nanoparticle-Embedded Carbon Coatings for Lithium-Ion Batteries

引用

Advanced Energy materials 2025年第0期

作者： Sun, Zhefei Yin, Quanzhi Zhou, Shenghui Chen, Haoyu Wen, Sifan Yang, Huiping Wu, Xiaoyu Pan, Jianhai Han, Jiajia Yang, Hui Zhuang, Zilong Feng, Shijie Zhang, Li Peng, Dong-Liang Zhang, Qiaobao State Key Laboratory of Physical Chemistry of Solid Surfaces College of Materials Xiamen University Xiamen361005 China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Tan Kah Kee Innovation Laboratory Collaborative Innovation Center of Chemistry for Energy Materials Xiamen University Fujian Xiamen361005 China State Key Laboratory of Material Processing and Die & Mould Technology Department of Mechanics School of Aerospace Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China Department of Mechanical Engineering University of Wisconsin-Madison MadisonWI53706 United States Materials Science and Engineering Program University of California San Diego La JollaCA92093 United States Longmen Laboratory Henan Luoyang471023 China

Silicon (Si) holds immense promise as viable anode for next-generation high-energy-density Li-ion batteries (LIBs). However, its poor ionic/electronic conductivity and significant volumetric changes during cycling lead to rapidly deteriorated LIB performance. Here, a novel multifunctional coating featuring ultrafine SiO2 nanoparticles (2-C) to resolve these challenges is proposed. This unique uSiO2-C coating provides high-efficient electron and ion transport pathways, while also improves interfacial stability and mitigates volume changes during cycling, thereby enhancing the conductivity and structural integrity of Si@uSiO2-C, as corroborated by extensive experimental and computational studies. In addition, the abundant interfaces in uSiO2-C coating facilitate Li+ transport and the evenly distributed ultrafine SiO2 nanoparticles impart high electrochemical reactivity and mechanical robustness. Consequently, the Si@uSiO2-C anode achieves a high reversible capacity of 2093 mAh g−1 at 0.2 A g−1, with a high initial Coulombic efficiency of 88.3%, superior rate capability and durability (1000 cycles, 928 mAh g−1 at 1.0 A g−1, 75% capacity retention). Full cells paired with commercial LiFePO4 cathodes demonstrate high cyclability, maintaining 80% capacity retention over 500 cycles at 4 C. This work highlights the vital role of multifunctional coating in promoting the electrochemical performance of Si-based anodes for high-performance LIBs. © 2025 Wiley-VCH GmbH.

关键词： SiO2 nanoparticles

来源：评论

学校读者我要写书评

暂无评论

SF6 Plasma Surface Modification of Flax Fibers for Improved Adhesion in Polypropylene Composites

引用

Fibers and Polymers 2025年第6期26卷 2569-2579页

作者： Veiga, Anderson Thiago Vasconcelos da Silva, Yuri Ferreira Cavalcante, Rafael Cordeiro Simão, Renata Antoun Metallurgical and Materials Engineering Program COPPE Federal University of Rio de Janeiro Av. Horácio Macedo 2030 F-213 RJ Rio de Janeiro21941-599 Brazil Department of Wood Science Faculty of Forestry The University of British Columbia 2424 Main Mall VancouverBCV6T 1Z4 Canada Université Paris-Saclay SFR Condorcet FR CNRS 3417 3 Rue Des Rouges Terres Pomacle51110 France Fraunhofer Institute for Machine Tools and Forming Technology IWU Theodor-Körner-Allee 6 Saxony Zittau02763 Germany

Flax fibers have attracted growing interest in the automotive industry as an eco-friendly reinforcement for polymer composites. However, their limited interfacial compatibility with hydrophobic matrices is detrimental to adhesion, a key factor in the composite mechanical behavior. To address this issue, this study investigates the surface modification of flax fibers using sulfur hexafluoride (SF6) plasma. The proposed treatment promotes fiber surface hydrophobization while preserving their bulk properties. The effect of SF6 plasma treatments on flax fiber adhesion to polypropylene (PP) blends containing post-consumer material is thoroughly examined. The analysis, conducted using scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, reveals that the plasma treatment induces the etching of amorphous substances present in the fibers, including amorphous cellulose, hemicelluloses, and lignin. Plasma etching in combination with fluorination significantly enhances the adhesion of flax fibers to the PP blend matrix. Notably, the treated fibers exhibit improvements in tensile strength (9%) and elastic modulus (25%) compared to untreated fibers. These findings highlight the potential of SF6 plasmas as an effective pretreatment method for natural fiber composite reinforcements. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.

关键词： Sulfur hexafluoride

来源：评论

学校读者我要写书评

暂无评论

Unavoidable multilevel biaxial symmetry breaking in chiral hybrid liquid crystals

引用

Physical Review E 2025年第4期111卷 045410-045410页

作者： Jin-Sheng Wu Marina Torres Lázaro Souvik Ghosh Haridas Mundoor Henricus H. Wensink Ivan I. Smalyukh Department of Physics and Chemical Physics Program University of Colorado Boulder Colorado 80309 USA Laboratoire de Physique des Solides–UMR 8502 Université Paris-Saclay and CNRS 91405 Orsay France International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima Japan Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA

Chiral nematic or cholesteric liquid crystals (LCs) are fluid mesophases with long-ranged orientational order featuring a quasilayered periodicity imparted by a helical director configuration but lacking long-range positional order. Doping molecular cholesteric LCs with strongly anisotropic uniaxial colloidal particles adds another level of complexity because of the interplay between weak surface-anchoring boundary conditions and bulk-based elastic distortions near the particle-LC interface. Using cylindrical colloidal disks and rods with different geometric shapes and surface conditions, we demonstrate that these colloidal inclusions generically exhibit biaxial orientational probability distributions which may impart anomalously strong local biaxiality onto the hybrid cholesteric LC structure. Unlike nonchiral hybrid molecular-colloidal LCs, where biaxial order emerges only at critical colloid volume fractions exceeding some uniaxial-biaxial transition value, the orientational probability of the colloidal inclusions immersed in chiral nematic hosts is unambiguously biaxial even at infinite dilution. We demonstrate that the colloids induce local biaxial perturbations within the molecular orientational order of the LC host medium which strongly enhances the weak but native biaxial order of chiral nematic LC induced by the chiral symmetry breaking of the director field. With the help of analytical modeling and computer simulations based on the Landau–de Gennes free energy of the host LC around the colloids, we rationalize the observed multilevel biaxial order and conclude that it is not only unavoidable but also strongly enhanced compared to both achiral hybrid LCs and purely molecular cholesteric LCs.

关键词： Cholesteric liquid crystals

来源：评论

学校读者我要写书评

暂无评论

HP40Nb reformer tube exposed to 950 °C – Machine learning informed microstructure evolution and multi-scale mechanical properties

引用

International Journal of Pressure Vessels and Piping 2025年 216卷

作者： Khan, Adnan Shunmugasamy, Vasanth C. Abuhelaiqa, Mousa Hamer, Wouter J. Laycock, Nicholas J. Mansoor, Bilal Department of Materials Science and Engineering Texas A&M University College StationTX United States Mechanical Engineering Program Texas A&M University at Qatar Doha Qatar Qatar Shell Research and Technology Center QSTP Doha Qatar Shell Global Solutions International B.V. Grasweg 31 Amsterdam1031 HW Netherlands

Austenitic stainless steel tubes extensively employed in energy sector, endure extreme service temperatures over long period of time and are susceptible to creep damage. This study investigates microstructural evolution and mechanical properties of HP40Nb (25Cr35Ni1Nb) steel exposed to 950 °C for up to 1600h, with specimens retrieved at 200h intervals. Advanced multi-scale characterization methods, including scanning electron microscopy, energy dispersive spectroscopy, and micro- and nanoindentation were utilized to analyze transformation of precipitates and resulting impact on mechanical properties. Microstructural changes (precipitate evolution, transformation and coarsening) were quantified using Machine Learning based algorithm and correlated with the mechanical properties. The as-cast microstructure comprised two primary intergranular Cr- and Nb-rich carbides in austenitic matrix. Post 200h exposure at 950 °C, secondary intragranular Cr-rich pepper carbide was observed in the austenite matrix. Following this, segregation of Si around Cr-rich precipitates occurred resulting in dark phases. At 800h, Si migrated to NbC resulting in transformation of NbC to Ni-Nb Silicide phase (G-phase). Transformation of NbC to G-phase and coarsening of the primary Cr-rich carbides was observed towards end of study at 1600h. The microstructural changes resulted in microcracks owing to precipitate transformation, coarsening and thermal coefficient mismatch. It was identified that both Nb and Cr precipitates are susceptible to microcracks post 800h at 950 °C. The study offers improved understanding of microstructural changes occurring in austenitic stainless steels used as reformer tubes during exposure to elevated service temperature. © 2025

关键词： Coarsening

来源：评论

学校读者我要写书评

暂无评论

engineering Andreev Bound States for Thermal Sensing in Proximity Josephson Junctions

arXiv

引用

arXiv 2025年

作者： Jung, Woochan Arnault, Ethan G. Huang, Bevin Park, Jinho Jang, Seong Watanabe, Kenji Taniguchi, Takashi Englund, Dirk Fong, Kin Chung Lee, Gil-Ho Physics Department Pohang University of Science and Technology Pohang37673 Korea Republic of Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States Intelligence Community Postdoctoral Research Fellowship Program Massachusetts Institute of Technology CambridgeMA02139 United States Department of Mechanical Engineering Columbia University New YorkNY10027 United States Research Center for Functional Materials National Institute for Materials Science Tsukuba Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science Tsukuba Japan Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical and Computer Engineering Northeastern University BostonMA02115 United States Department of Physics Northeastern University BostonMA02115 United States Quantum Materials and Sensing Institute BurlingtonMA01803 United States

The thermal response of proximity Josephson junctions (JJs) is governed by the temperature (T)- dependent occupation of Andreev bound states (ABS), making them promising candidates for sensitive thermal detection. In this study, we systematically engineer ABS to enhance the thermal sensitivity of critical current (lc) of proximity JJs, quantified as |dlc/dT/| for threshold readout scheme and |dlc/***−1| for inductive readout scheme. Using a gate-tunable graphene-based JJ platform, we explore the impact of key parameters—including channel length, transparency, carrier density, and superconducting material—on the thermal response. Our results reveal that the proximity-induced superconducting gap plays a crucial role in optimizing thermal sensitivity. Notably, we see a maximum |dlc/***−1| value of 0.6 K−1 at low temperatures with titanium-based graphene JJs. By demonstrating a systematic approach to engineering ABS in proximity JJs, this work establishes a versatile framework for optimizing thermal sensors and advancing the study of ABS-mediated transport. © 2025, CC BY.

关键词： Superconducting materials

来源：评论

学校读者我要写书评

暂无评论

Early and advanced crystallization stages in lithia-alumina-silica glasses nucleated by ZrO2

引用

Ceramics International 2025年

作者： Revelo, Raúl Julián Souza, Mauricio Lima Pena, Rafaella Bartz Yoshida, Satoshi Zanotto, Edgar Dutra Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil São Carlos Institute of Physics University of São Paulo SP São Carlos13566-590 Brazil Materials Integration Laboratories AGC Inc 1-1 Suehiro-Cho Tsurumi-Ku Kanagawa Yokohama230-0045 Japan

ZrO2 is one of the most effective and widely used nucleating agents in various families of glass-ceramics;however, its detailed mechanism remains a subject of debate. Understanding its nucleation mechanism requires a thorough analysis of microstructural evolution and the identification of factors influencing this process. This study investigates the effects of ZrO2 incorporation on the internal nucleation and microstructural evolution in stoichiometric LAS (Li2O·Al2O3·nSiO2) glass-ceramics of varying composition. Glasses with different SiO2 molar ratios (n = 2, 4, 5, and 6) were prepared with ZrO2 additions of 3.0 and 3.5 mol%. Several thermal treatments were employed, followed by characterization using XRD, SEM, STEM, and Raman spectroscopy. The results indicate that a minimum of 3.5 mol% ZrO2 is required to induce internal nucleation in LAS glasses with n = 4, 5, and 6. In these compositions, Zr-enriched regions formed through liquid-liquid phase separation serve as preferential sites for ZrO2 crystal precipitation, which subsequently induces the nucleation of β-quartz solid solution. Upon further treatment at higher temperatures, this metastable phase transforms into β-spodumene or its solid solution. As expected, increasing SiO2 content enhances glass network polymerization, as evidenced by the increased presence of Q3 species in Raman spectroscopy, leading to higher characteristic temperatures of glass transition and peak crystallization in DSC analyses. A higher SiO2 content results in fewer but larger crystals, whereas a lower SiO2 content promotes a higher number density of crystals within the glass matrix. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Glass ceramics

来源：评论

学校读者我要写书评

暂无评论

Optimal sandwich panel's core design for an enhanced impact resistance

引用

Heliyon 2025年第1期11卷 e41211页

作者： Charkaoui, Assil Hassan, Noha M. Bahroun, Zied Materials Science and Engineering Program College of Arts and Sciences American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates Department of Industrial Engineering College of Engineering American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates

Despite the extensive literature revealing various core structures that can enhance the impact resistance of composite panels, a comparative study illustrating the difference in performance of the various cores under same loading conditions is missing. The aim of this study is to determine the optimal core structure and design in terms of energy absorption under low-velocity impact using both numerical simulations and experimental testing for validation. Response surface analysis was used to design the experiments and analyse the panel's behaviour. A total of 160 numerical simulations were conducted by varying the core shape, density, number of layers and panel's thickness. Drop tower tests were performed to experimentally validate the results. Additive manufacturing was used to 3D print the tested structures which simplified the manufacturing process. Results provided insights on time to perforation, stiffness of the panels showcasing an inverse relationship between recoverable strain energy and equivalent plastic strain. The number of layers within the panels were identified as a pivotal factor in the energy distribution and tendency for localized plastic deformation to occur. Both numerical and experimental results revealed the superior energy absorption capabilities of the X-frame core shaped structure. Regression models developed shed light on the relationships between core height, volume fraction, number of layers, and core topology revealing the extent of damage. Multi-objective optimization was used to yield optimal configuration for sandwich panels with highest impact resistance. © 2024

关键词： Additive manufacturing Core geometry Energy absorption Impact resistance Optimization Sandwich panels

来源：评论

学校读者我要写书评

暂无评论

Nanoimprinted Sticky Hydrophobic SU-8 Nanopillars for Ultra-Sensitive Surface-Enhanced Raman Spectroscopy Applications

引用

ACS Applied Nano materials 2025年第19期8卷 10087-10095页

作者： Chang, Wen-Huei Wu, Yu-Cheng Shieh, Jiann Kuo, Kuan-Ting Huang, Chih-Chia Cheng, Horng-Long Lin, Chun-Hung Department of Applied Chemistry National Pingtung University Pingtung90003 Taiwan Department of Photonics National Cheng Kung University Tainan70101 Taiwan Department of Materials Science and Engineering National United University Miaoli36063 Taiwan Meta-nanoPhotonics Center National Cheng Kung University Tainan70101 Taiwan Program on Key Materials Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan70101 Taiwan

This study demonstrates the development of a sticky hydrophobic SU-8 nanopillar substrate combined with silver nanoparticles (AgNPs) for highly sensitive surface-enhanced Raman scattering (SERS) detection. The SU-8 nanopillars were fabricated using nanoimprint lithography (NIL) and modified with fluoride treatments to achieve sticky and hydrophobic properties, which enhance analyte concentration and SERS signal strength. SU-8 was selected for its durability, chemical resistance, and ease of modification, whereas NIL provided cost-effective, scalable, and precise nanoscale patterning, crucial for creating high-performance SERS substrates. Self-synthesized AgNPs, produced via a citrate reduction method, exhibited strong SERS signals due to their irregular shapes and sharp tips, enhancing localized surface plasmon resonance (LSPR) effects. The SERS performance of this system was evaluated using malachite green as a model analyte. Detection limits down to 10-17 M were achieved in deionized water and river water, demonstrating exceptional sensitivity. In seawater, detection was limited to 10-12 M due to salt deposition affecting the LSPR effect. The sticky hydrophobic substrate enabled precise analyte localization and reproducibility across different substrates, making this approach highly effective for ultralow concentration detection. This method presents a cost-efficient, scalable, and highly sensitive platform for SERS applications, offering detection capabilities beyond conventional limits for environmental monitoring and pollutant detection. © 2025 The Authors. Published by American Chemical Society.

关键词： Nanoimprint lithography

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：