检索结果-内蒙古大学图书馆

SSRN 2024年

作者： Nenninger, Tara Sansoz, Frederic Department of Mechanical Engineering The University of Vermont BurlingtonVT05405 United States Materials Science Program The University of Vermont BurlingtonVT05405 United States

Spectral analysis of local atomic environments has become a powerful tool for studying solute atom segregation and interactions at grain boundaries in nanocrystalline alloys. When applied to individual grain boundaries, the spectral analysis has shown that solute-solute interaction can be either attractive or repulsive, with long-range relative attraction enhancing the likelihood for solute cluster nucleation. In this article, we combine this analysis with a new grain-boundary structure descriptor based on grain-boundary atom coordination, to investigate the impact of grain-boundary junctions on solute atom segregation in polycrystals. Specifically, we systematically characterize the nucleation tendency of solute clusters at various types of ordinary grain boundaries, triple junctions, and high-order junctions in Ag polycrystals containing either Ni or Cu solute atoms. Our findings demonstrate that the nucleation of solute clusters at grain boundaries is primarily driven by long-range relative solute attraction, rather than short-range solute-solute interactions. This effect is most pronounced near grain-boundary junctions. Our study highlights the multiscale nature of solute segregation at crystalline interfaces and provides new insights into the complex phenomena governing heterogeneous solute segregation in grain-boundary networks. © 2024, The Authors. All rights reserved.

关键词： Nanocrystalline alloys

来源：评论

学校读者我要写书评

暂无评论

Effect of Parasitic Leakage Currents Associated with the Regrown Aperture of AlGaN/GaN Current Aperture Vertical Electron Transistors (CAVETs)

Effect of Parasitic Leakage Currents Associated with the Reg...

引用

IEEE Electron Devices Technology and Manufacturing Conference (EDTM)

作者： Sara Pouladi Jae Hyun Ryou Department of Mechanical Engineering Texas Center for Superconductivity at UH Advanced Manufacturing Institute University of Houston USA Department of Electrical and Computer Engineering Materials Science and Engineering Program University of Houston USA

We present a numerical simulation on the effect of leakage paths in the regrown GaN layer in the aperture and above the current blocking layer (CBL) of current aperture vertical electron transistor (CAVET) devices. Here, a 2D TCAD modeling is employed to simulate a CAVET device structure considering two main origins of parasitic leakage current from CBL/regrown-GaN interface and gate/regrown-GaN bulk and their degree of detrimental effect on the characteristics of AlGaN/GaN CAVETs.

关键词： Performance evaluation Apertures Logic gates Numerical simulation Wide band gap semiconductors Numerical models Leakage currents

来源：评论

学校读者我要写书评

暂无评论

Transparent Porphyrin-Based Hybrid Films for Spectral Selective Solar Harvesting and Energy Generation

SSRN

引用

SSRN 2022年

作者： Shi, Donglu Lin, Jou Wang, Yuxin Lyu, Mengyao Deng, Zicheng The Materials Science and Engineering Program Department of Mechanical Materials Engineering College of Engineering and Applied Science University of Cincinnati CincinnatiOH45221 United States

Spectral-selectively solar harvest is achieved in designated frequency regions for photothermal energy generation. In this study, we have designed and synthesized porphyrin-based hybrids that typically exhibit two absorption peaks respectively near 400 nm (blue-violet) and 700 nm (NIR). To be able to tune the optical absorptions for more efficient solar harvest especially in the IR region, unique porphyrin hybrids are developed by incorporating another porphyrin compound such as phthalocyanine, and inorganic Fe 3 O 4 @Cu 2-x S nanoparticles with different absorption characteristics. By controlling the ratio of the components, the hybrids exhibit gradual and consistent changes in the optical spectra, showing high spectral tunability. Transparent thin films of the hybrids are deposited on glass substrates and constructed in parallel for 3D solar harvesting in a cuboid photothermal generator. Solar light is able to pass through the multilayers of thin films, generating significant thermal heat on each one for enhanced energy density. The structural features of the hybrids are well correlated to the optical behaviors based on Raman studies. Also discussed is the operating mechanisms underlying the photothermal behaviors associated with the hybrid structures. © 2022, The Authors. All rights reserved.

关键词： Multilayers

来源：评论

学校读者我要写书评

暂无评论

Performance-driven Computational Design of Multi-terminal Compositionally Graded Alloy Structures using Graphs

arXiv

引用

arXiv 2024年

作者： Allen, Marshall D. Attari, Vahid Vela, Brent Hanagan, James Malak, Richard Arróyave, Raymundo J. Mike Walker’66 Department of Mechanical Engineering Texas A&M University College StationTX77843 United States Department of Materials Science and Engineering Texas A&M University College StationTX77843 United States

The spatial control of material placement afforded by metal additive manufacturing (AM) has enabled significant progress in the development and implementation of compositionally graded alloys (CGAs) for spatial property variation in monolithic structures. However, cracking and brittle phase formation have hindered CGA development, with limited research extending beyond materials design to structural design. Notably, the high-dimensional alloy design space (systems with more than three active elements) remains poorly understood, specifically for CGAs. As a result, many prior efforts take a trial-and-error approach. Additionally, current structural design methods are inadequate for joining dissimilar alloys. In light of these challenges, recent work in graph information modeling and design automation has enabled topological partitioning and analysis of the alloy design space, automated design of multi-terminal CGAs, and automated conformal mapping of CGAs onto corresponding structural geometries. In comparison, prior gradient design approaches are limited to two-terminal CGAs. Here, we integrate these recent advancements, demonstrating a unified performance-driven CGA design approach on a gas turbine blade with broader application to other material systems and engineering structures. © 2024, CC BY-NC-SA.

关键词： Structural properties

来源：评论

学校读者我要写书评

暂无评论

Enhancing PV solar panel efficiency through integration with a passive Multi-layered PCMs cooling system: A numerical study

引用

International Journal of Thermofluids 2024年 23卷

作者： Sheikh, Yahya Jasim, Muhammad Qasim, Muhammad Qaisieh, Alaa Hamdan, Mohammad O. Abed, Farid Materials Science and Engineering Program American University of Sharjah Sharjah United Arab Emirates Department of Mechanical Engineering American University of Sharjah Sharjah United Arab Emirates Department of Chemical and Biological Engineering American University of Sharjah Sharjah United Arab Emirates Civil Engineering Department American University of Sharjah Sharjah United Arab Emirates

Photovoltaic (PV) solar cells are at the forefront of sustainable electricity generation technologies, yet they exhibit relatively low efficiency. Typically, less than 20 % of the solar energy absorbed is converted into electrical energy, with the remainder converts into heat. This heat increases the PV panel's operating temperature, negatively impacting its efficiency and life expectancy. To mitigate this, a novel approach using multi-layered phase change materials (PCMs) has been examined in this study. The approach involves integrating organic PCMs (OPCMs) with metallic PCMs (MPCMs), enhancing PV panel cooling efficiency by attaching the multi-layer PCM to the panel's rear. This study, employing ANSYS FLUENT software's solidification and melting model, explores the impact of multi PCM layers thickness and total multi layers thickness on PV cell temperature and electrical efficiency. The analysis reveals that a multi-layered PCMs configuration with a thickness ratio of 15:85 between MPCM (CERROLOW-117® alloy) and OPCM (RT44) significantly decreases temperature rise in PV cells, resulting in a temperature drop of 59.6 °C. This improvement boosts PV panel performance by an average of 35.8 % compared to panels lacking cooling systems during peak sun hours under hot climate conditions characterized by ambient temperatures of 40 °C and high solar radiation exceeding 1000 W/m². This suggests that a carefully optimized PCM layering approach could markedly improve PV system efficiency, offering a practical solution to the overheating problem and extending the operational life of PV installations. © 2024 The Author(s)

关键词： Phase change materials

来源：评论

学校读者我要写书评

暂无评论

Surface Characterization of Sodium Cholate Treated CVD Graphene

Surface Characterization of Sodium Cholate Treated CVD Graph...

引用

IEEE Conference on Nanotechnology

作者： Evans Addo-Mensah Janet Obaemo Katie Welch Yang Tian Shiva Dolatabadi Hugh Churchill Uchechukwu Wejinya Materials Science and Engineering Graduate Program University of Arkansas Microelectronics and Photonics Program University of Arkansas Department of Physics University of Arkansas Fayetteville Arkansas Department of Mechanical Engineering University of Arkansas Fayetteville Arkansas

The advancement of graphene has created a need in exploring its properties for different applications. One way to explore its properties is by reducing its hydrophobicity. To overcome hydrophobicity of graphene, surfactants have been used in functionalization, hence improving the surface properties of the graphene monolayer. Therefore, investigating surfactant treatment for CVD graphene becomes useful in understanding the surface property effects on graphene. This study utilizes CVD graphene on silicon substrates. Its treatment was done with varying concentrations of Sodium Cholate (SC) for different treatment times. These samples were then characterized using Atomic Force Microscopy (AFM) to investigate the surface properties of the samples before and after treatment. To be optimized, the graphene must remain attached to the silicon substrate. The result shows that the integrity of the graphene, which is basically the Sp2 structure, is preserved as there was no delamination from the substrate even after treatment for as long as 2 hours in 1% weight/volume concentration of the SC solution.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Opto2P-FCM: A MEMS Based Miniature Two-Photon Microscope with Patterned Optogenetic Stimulation

Opto2P-FCM: A MEMS Based Miniature Two-Photon Microscope wit...

引用

Microscopy Histopathology and Analytics, Microscopy 2024 - Part of Optica Biophotonics Congress: Biomedical Optics

作者： Futia, Gregory L. Zohrabi, Mo McCullough, Connor Teel, Alec de Souza, Fabio Simoes Oroke, Ryan Bright, Victor M. Restrepo, Diego Gopinath, Juliet T. Gibson, Emily A. Department of Bioengineering University of Colorado Anschutz Medical Campus AuroraCO80045 United States Department of Cell and Developmental Biology University of Colorado Anschutz Medical Campus AuroraCO80045 United States Department of Electrical Computer and Energy Engineering University of Colorado BoulderCO80309 United States Department of Mechanical Engineering University of Colorado BoulderCO80309 United States Department of Physics University of Colorado BoulderCO80309 United States Materials Science and Engineering Program University of Colorado BoulderCO80309 United States

Miniaturized microscopes for monitoring neural activity are an indispensable tool for neuroscience research. We present a novel MEMS based miniature microscope with patterned optogenetic stimulation capabilities enabl... 详细信息

ISBN: (纸本)9781957171340

关键词： Microscopes

来源：评论

学校读者我要写书评

暂无评论

Cracking Prediction at Solid-Tooth Support Interface During Laser Powder Bed Fusion Additive Manufacturing

SSRN

引用

SSRN 2023年

作者： To, Albert C. Tran, Hai T. J. Mike Walker’66 Department of Mechanical Engineering Texas A&M University College StationTX77843 United States Department of Mechanical Engineering and Materials Science University of Pittsburgh PittsburghPA15261 United States

Cracking resulted from residual stress at the solid-tooth support interface frequently occurs in laser powder bed fusion (LPBF) metallic additive manufacturing, and thus it is critical to predict possible cracking and design the support to prevent it. This study employs a combination of computational methods and experiments to predict cracking at the interface and, for the first time, determine the relationship between the critical J-integral and the contact area of the solid-tooth support interface. In particular, the finite element method-based global-local approach is used to perform the modified inherent strain analysis with homogenized material for the entire part (global), which is followed by the fracture mechanics-based J-integral analysis at conjectured vulnerable locations (local). Both numerical and experimental validations are conducted showing that the local-global approach is both accurate and efficient in crack prediction at the interface between the solid and the tooth support in as-built LPBF printed metals. It is found that given the same basic tooth unit design in the support structure, the critical J-integral increases at an approximate linear slope of 2 with local contact area percentage (~20-40%) at the solid-support interface. These results will enable support designers the flexibility to design the support contact area to prevent solid-tooth support cracking while ensuring the ease of support removal. © 2023, The Authors. All rights reserved.

关键词： 3D printing

来源：评论

学校读者我要写书评

暂无评论

Epilayer on NEAT Grown GaN Schottky Diodes for Radiation Detection

Epilayer on NEAT Grown GaN Schottky Diodes for Radiation Det...

引用

2023 Transactions of the American Nuclear Society Annual Meeting and Technology Expo, ANS 2023

作者： Remy, Jarod Zhang, Yuxuan Talesara, Vishank Zhao, Hongping Lu, Wu Hashimoto, Tadao Cao, Lei R. Nuclear Engineering Program Department of Mechanical and Aerospace Engineering 281 W. Lane Ave. ColumbusOH43210 United States Department of Electrical and Computer Engineering 281 W. Lane Ave ColumbusOH43210 United States Department of Material Science and Engineering The Ohio State University 281 W. Lane Ave ColumbusOH43210 United States SixPoint Materials Inc 37 Industrial Way STE 106 BuelltonCA United States

来源：评论

学校读者我要写书评

暂无评论

Real-time in situ study of adsorption kinetics in PMMA thin films using infrared spectroscopy

Real-time in situ study of adsorption kinetics in PMMA thin ...

引用

Computational Optical Sensing and Imaging, COSI 2022

作者： Lee, Tse-Ang Kowal, Gina Peng, Jessie Hutter, Tanya Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States Department of Psychology University of Texas at Austin AustinTX78712 United States Department of Biomedical Engineering University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program Texas Materials Institute University of Texas at Austin AustinTX78712 United States

Studying adsorption in polymers is important for many applications. We present results on real-time in situ adsorption of ethanol and water in thin polymethyl methacrylate (PMMA) layers using attenuated total reflecti... 详细信息

ISBN: (纸本)9781557528209

关键词： Polymethyl methacrylates

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：