检索结果-内蒙古大学图书馆

arXiv 2025年

作者： Anadón, Alberto Singh, Harjinder Díaz, Eva Le-Guen, Yann Hohlfeld, Julius Wilson, Richard B. Malinowski, Gregory Hehn, Michel Gorchon, Jon Université de Lorraine CNRS IJL NancyF-54000 France Department of Mechanical Engineering and Materials Science and Engineering Program University of California RiversideCA United States

Magneto-optical techniques have become essential tools in spintronics, enabling the investigation of spin dynamics in the ultrafast regime. A key challenge in this field has been to accurately isolate the contributions to magneto-optical signals of spin transport phenomena from the local magnetization dynamics. The contribution of transported and accumulated spins was long believed to be orders of magnitude smaller than that of the magnetization and thus previous approaches to disentangle these signals have relied on specific experimental designs, usually including thick metal layers. Here, we present experimental evidence demonstrating that the magneto-optical signal from ultrafast spin accumulations can, under certain conditions, be comparable to or even exceed that of the magnetic layer in a standard ultrafast demagnetization experiment. Our findings provide a new framework for accessing and isolating these spin accumulations, allowing for time and depth dependent probing of transported spin and/or orbital angular momentum. © 2025, CC BY.

关键词： Spin dynamics

来源：评论

学校读者我要写书评

暂无评论

Two-Layer High-Throughput:Effective Mass Calculations Including Warping

引用

engineering 2022年第3期8卷 74-80页

作者： Andrew Supka Nicholas A.Mecholsky Marco Buongiorno Nardelli Stefano Curtarolo Marco Fornari Department of Physics&Science of Advanced Materials Program Central Michigan UniversityMount PleasantMI 48859USA Department of Physics&Vitreous State Laboratory The Catholic University of AmericaWashingtonDC 20064USA Department of Physics&Department of Chemistry University of North TexasDentonTX 76203USA Center for Autonomous Materials Design Duke UniversityDurhamNC 27708USA Department of Mechanical Engineering and Materials Science Duke UniversityDurhamNC 27708USA

In this paper,we perform two-layer high-throughput *** the first layer,which involves changing the crystal structure and/or chemical composition,we analyze selected Ⅲ-Ⅴ semiconductors,filled and unfilled skutterudites,as well as rock salt and layered *** second layer searches the full Brillouin zone(BZ)for critical points within 1.5 eV(1 eV=1.602176×10^(-19)J)of the Fermi level and characterizes those points by computing the effective *** introduce several methods to compute the effective masses from first principles and compare them to each *** approach also includes the calculation of the density-of-states effective masses for warped critical points,where traditional approaches fail to give consistent results due to an underlying non-analytic behavior of the critical *** demonstrate the need to consider the band structure in its full complexity and the value of complementary approaches to compute the effective *** also provide computational evidence that warping occurs only in the presence of degeneracies.

关键词： High-throughput Electronic structure Band warping Effective mass

来源：评论

学校读者我要写书评

暂无评论

Study on the Flow, Foaming Characteristics and Structural Strength of Polypropylene Structural Foam Injection Molding by Innovative Nitrogen and Molten Plastic Mixing Mechanism

引用

Polymers 2023年第9期15卷 2116-2116页

作者： Huang, Po-Wei Peng, Hsin-Shu Hwang, Sheng-Jye Huang, Chao-Tsai Program of Mechanical and Aeronautical Engineering Feng Chia University of Engineering and Science Taichung407102 Taiwan Department of Mechanical and Computer Aided Engineering Feng Chia University of Engineering and Science Taichung407102 Taiwan Department of Mechanical Engineering National Cheng Kung University of Engineering Tainan70101 Taiwan Department of Chemical and Materials Engineering Tamkang University of Engineering New Taipei City251301 Taiwan

Plastic foam molding methods include thermoforming, extrusion and injection molding. Injection foam molding is a one-time molding method with high production efficiency and good product quality. It is suitable for foamed plastic products with complex shapes and strict size requirements. It is also the main method for producing structural bubbles. In this investigation, we developed a structural foam injection molding technology using the gas supply equipment connected to the unique plasticizing mechanism of the injection machine and studied its influence on the specimens’ melt rheology quality and foam structures. In the experiment, the forming material was polypropylene (PP), and the gas for mixing/forming foaming characteristics was nitrogen (N2). Additionally, in order to observe the rheological properties of N2/melt mixing, a melt flow specimen mold cavity was designed and the change in the melt viscosity index was observed using a melt pressure sensing element installed at the nozzle position. With the nitrogen supply equipment connected to a unique plasticizing mechanism, the mixing of gas and molten plastic can be achieved at the screw plasticizing stage, where the foaming effect is realized during the melt-filling process due to the thermodynamic instability of the gas. It was also found that an increase in N2 fill content increased melt fluidity, and the trend of melt pressure and melt viscosity index showed that the higher the gas content, the lower the trend. The foaming characteristic depends on the gas thermodynamic instability and the pressure release, so it can be seen from the melt fill path that, the greater the pressure near the gate, the lower the foaming amount and the internal structure (SEM) after molding;the farther from the gate, the greater the relative increase in the foaming growth/amount. This phenomenon will be more obvious when the N2 fill content is increased. © 2023 by the authors.

关键词： Gases

来源：评论

学校读者我要写书评

暂无评论

Atomistic modeling and rational design of optothermal tweezers for targeted applications

引用

Nano Research 2021年第1期14卷 295-303页

作者： Hongru Ding Pavana Siddhartha Kollipara Linhan Lin Yuebing Zheng Walker Department of Mechanical Engineering The University of Texas at AustinAustinTX 78712USA State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China Materials Science&Engineering Program and Texas Materials Institute The University of Texas at AustinAustinTX 78712USA

Optical manipulation of micro/nanoscale objects is of importance in life sciences,colloidal science,and *** tweezers exhibit superior manipulation capability at low optical ***,our implicit understanding of the working mechanism has limited the further applications and innovations of optothermal ***,we present an atomistic view of opto-thermo-electro-mechanic coupling in optothermal tweezers,which enables us to rationally design the tweezers for optimum performance in targeted ***,we have revealed that the non-uniform temperature distribution induces water polarization and charge separation,which creates the thermoelectric field dominating the optothermal *** further design experiments to systematically verify our atomistic *** by our new model,we develop new types of optothermal tweezers of high performance using low-concentrated ***,we demonstrate the use of new tweezers in opto-thermophoretic separation of colloidal particles of the same size based on the difference in their surface charge,which has been challenging for conventional optical *** the atomistic understanding that enables the performance optimization and function expansion,optothermal tweezers will further their impacts.

关键词： optothermal tweezers optical tweezers optical manipulation thermophoresis molecular dynamics simulation

来源：评论

学校读者我要写书评

暂无评论

!D-architected gratings for polarization-sensitive, nature-inspired structural color

arXiv

引用

arXiv 2024年

作者： Ibarra Miranda, Moisés H. Osterberg, Lars W. Shah, Dev H. Regulagadda, Kartik Poulikakos, Lisa V. Department of Mechanical and Aerospace Engineering Program of Materials Science and Engineering University of California San Diego La Jolla CA United States Program of Materials Science and Engineering University of California San Diego La Jolla CA United States Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA United States Laboratory for Multiphase Thermofluidics and Surface Nanoengineering Department of Mechanical Engineering University of California BerkeleyCA United States

Structural coloration, a color-generation mechanism often found in nature, arises from light-matter interactions such as diffraction, interference and scattering, with micro- and nanostructured elements. Herein, we systematically study anisotropic,:D-architected grating structures with polarization-tunable optical properties, inspired by the vivid blue of Morpho butterfly wings. Using two-photon lithography, we fabricate multilayered gratings, varying parameters such as height (through scanning speed and laser power), periodicity, and number of layers. In transmission, significant color transitions from blue to brown were identified when varying structural parameters and incident light polarization conditions (azimuthal angle and ellipticity). Based on thin film diffraction efficiency theory in the Raman-Nath regime, optical characterization results are analytically explained, evaluating the impact of each parameter variation. Overall, these findings contribute to technological implementations of polarization-sensitive,:D-architected gratings for structural color applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Color

来源：评论

学校读者我要写书评

暂无评论

Thermodynamic and Environmental Assessment of Low-GWP Alternative Refrigerants for Domestic Cooling

引用

Journal of The Institution of Engineers (India): Series C 2023年第2期104卷 377-383页

作者： Islam, Md. Amirul Rupam, Tahmid Hasan Hosan, Shahadat Saha, Bidyut Baran Institute for Materials Chemistry and Engineering Kyushu University Kasuga-Koen 6-1 Kasuga-Shi Fukuoka816-8580 Japan Department of Electrical and Electronics Engineering Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalganj8100 Bangladesh Kyushu University 744 Motooka Nishi-Ku Fukuoka819-0395 Japan Kyushu University Program for Leading Graduate School Green Asia Education Center Kyushu University Fukuoka Japan Department of Mechanical Engineering Kyushu University 744 Motooka Nishi-Ku Fukuoka819-0395 Japan

Nearly two billion air-conditioning (AC) units are currently being used for space cooling worldwide. The majority of these ACs use R134a as the working fluid, a greenhouse gas (GHG) with a global warming potential (GWP) of 1300 kg-CO2-eq. According to the rules set by the world environment safety organizations, the GWP of domestic air-conditioning systems must not exceed 750 kg-CO2-eq. Hence, the R134a must be phased out by 2025, and an alternative refrigerant with similar thermodynamic properties yet low GWP is required. Therefore, the authors have investigated several potential binary/ternary refrigerant blends in this study. Among the studied refrigerants, R445A, R30A, and NPB2 (newly proposed blend: 8% R152a + 92% R1234yf) can reduce 90–99% global warming impact (more than 200 million tonnes of CO2 emission equivalent) caused by the domestic air-conditioning systems every year. © 2023, The Institution of Engineers (India).

关键词： Refrigerants

来源：评论

学校读者我要写书评

暂无评论

Flexible organic solar cells for biomedical devices

引用

Nano Research 2021年第9期14卷 2891-2903页

作者： Bin Kan Faheem Ershad Zhoulyu Rao Cunjiang Yu Department of Mechanical Engineering University of HoustonHoustonTX 77204USA Department of Biomedical Engineering University of HoustonHoustonTX 77204USA Materials Science and Engineering Program University of HoustonHoustonTX 77204USA Department of Electrical and Computer Engineering University of HoustonHoustonTX 77204USA Texas Center for Superconductivity University of HoustonHoustonTX 77204USA

Organic solar cells(OSCs),particularly made based on solution processing methods,have made significant progress over the past decades through the concurrent evolution of organic photovoltaic materials and device ***,high power conversion efficiencies around 18%and over 16%have been demonstrated in both rigid and flexible OSCs,*** most of the OSC research has centered on efficiency and cost,their emerging and potential usages in many critical applications,particularly in biomedical fields have been *** this mini-review,we will briefly discuss the high-performance organic photovoltaic materials and the representative flexible OSCs to give a scope on the recent rapid development of ***,we will review some progress on the applications of OSCs in biomedical devices and integrated *** potential challenges associated with integrating OSCs for biomedical devices will be put forward.

关键词： organic solar cells photovoltaic flexible biomedical bioelectronics

来源：评论

学校读者我要写书评

暂无评论

Water Distillation-Advances, Challenges & Future Directions: A Brief Review

Water Distillation-Advances, Challenges & Future Directions:...

引用

IEEE International Conference on Emerging & Sustainable Technologies for Power & ICT in a Developing Society (NIGERCON)

作者： Remilekun R. Elewa Temitayo S. Ogedengbe Olawale Charles Ogunnigbo Sunday A. Afolalu Moses E. Emetere Adediran A.A Oluwatoyin Augustine Ojo Mechanical and Mechatronics Engineering Department Afe Babalola University Ado-Ekiti Nigeria Mechanical Engineering Department Nile University of Nigeria Abuja Department of Mechanical Science University Johannesburg South Africa Physics Program. Bowen University Iwo Osun State Nigeria Department of Metallurgical & Materials Engineering Federal University Ekiti Nigeria Department of Mechanical Engineering Science University of Johannesburg South Africa

ISBN: (数字)9798331542559

ISBN: (纸本)9798331542566

Every human being has the basic need for clean drinking water, however 1.1 billion people worldwide do not have access to it. While there are other methods for purifying water, including filtration, reverse osmosis, UV light, and carbon absorption, but distillation and boiling are the most dependable. Distillation is a vital method of purifying water, particularly in areas where tap water or water resources are unfit for human consumption without chemical or heating treatment. This review discusses the recent advances in water distillation. The techniques employed and challenges involved have also been discussed. Finally, the future direction of technology in this regard has been reviewed.

关键词： Humanities Heat treatment Reviews Purification Filtration Water heating Production Reverse osmosis Water resources Chemicals

来源：评论

学校读者我要写书评

暂无评论

First principles derivation of a Rayleigh Gans Debye model for scattering from anisotropic inhomogeneities

arXiv

引用

arXiv 2023年

作者： Shachar, M.H. Garay, J.E. Materials Science & Engineering Program Mechanical & Aerospace Engineering Department University of California San Diego La Jolla CA United States

Scattering problems are important in describing light propagation in wide ranging media such as the atmosphere, colloidal solutions, metamaterials, glass ceramic composites, transparent polycrystalline ceramics, and surfaces. The Rayleigh-Gans-Debye (RGD) approximation has enjoyed great success in describing a wide range of scattering phenomena. We derive a generalized RGD formulation from the perturbation of Maxwell’s equations. In contrast to most treatments of RGD scattering, our formulation can model any soft scattering phenomena in linear media, including scattering by stochastic process, lossy media, and by anisotropic inhomogeneities occurring at multiple length scales. Our first-principles derivation makes explicit underlying assumptions and provides jumping-off points for more general treatments. The derivation also facilitates a deeper understanding of soft scattering. It is demonstrated that sources of scattering are not interfaces as is often presumed, but excess accelerating charges emitting uncompensated radiation. Approximations to the equations are also presented and discussed. For example, the scattering coefficient in the large-size RGD limit is shown to be proportional to the correlation length and the variance of a projected phase shift. © 2023, CC BY.

关键词： Random processes

来源：评论

学校读者我要写书评

暂无评论

Preparation of Graphene Aerogel for Application in Solar Energy Harvesting

Preparation of Graphene Aerogel for Application in Solar Ene...

引用

2022 Advances in science and engineering Technology International Conferences, ASET 2022

作者： Alhammadi, Alya Alnaqbi, Amna Almarashda, Meera Alasad, Shamma Alashkar, Adnan Inayat, Abrar Abdelkareem, Mohammad Alami, Abdul Hai University of Sharjah Sustainable and Renewable Energy Engineering Department Sharjah United Arab Emirates American University of Sharjah Mechanical Engineering Department Sharjah United Arab Emirates American University of Sharjah Materials Science and Engineering PhD Program Sharjah United Arab Emirates

ISBN: (纸本)9781665418010

In this paper, Graphene Aerogel (GA) is prepared and investigated for its potential employment for solar energy harvesting applications. GA can be applied in solar cells applications as an absorption material and as a catalyst for fuel cells. GA is characterized by its extraordinary electrical conductivity and mechanical strength, in addition to a large surface and a low density. The electrical, mechanical, thermal, and absorption characteristics of GA can be tuned depending on the manufacturing process. Hence, GA is utilized in a multitude of applications such as: supercapacitors, air purification, oil and dye absorption from water, and water waste treatment. GA is also an excellent candidate for superior electrodes. In addition, GA are environmentally friendly materials since they are 100% recyclable and do not produce any ozone-depleting compounds. In this paper, GA is synthesized, characterized, and assessed for solar energy harvesting applications with the aid of absorption and Cyclic voltammetry (CV) tests. Results show that GA has immense potential in solar application due to its low band gap and outstanding optical and electrochemical properties. © 2022 IEEE.

关键词： Cyclic voltammetry

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：