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Absence of superconductivity in micrometer-sized ɛ-NbN single crystals

Physical Review B 2022年第17期105卷 174512-174512页

作者： Fan-Yun Chiu Tsu-Lien Hung Cheng-Yen Liu Ya-Hsin Pai Wei-Liang Chien Peng-Jen Chen Ting-Kuo Lee Ming-Jye Wang Min-Nan Ou Chang C. Tsuei Maw-Kuen Wu Chia-Seng Chang Yang-Yuan Chen Department of Physics National Taiwan University Taipei 106319 Taiwan Republic of China Institute of Physics Academia Sinica Taipei 115201 Taiwan Republic of China Nano science and Technology program Taiwan International Graduate Program Taipei 115201 Taiwan Republic of China Department of Materials Science and Engineering National Taiwan University Taipei 106319 Taiwan Republic of China Department of Mechanical Engineering City University of Hong Kong Kowloon Hong Kong SAR China Hong Kong Institute for Advanced Study City University of Hong Kong Kowloon Hong Kong SAR China Department of Physics National Sun Yat-sen University Kaohsiung 804201 Taiwan Republic of China Institute of Astronomy and Astrophysics Academia Sinica Taipei 106319 Taiwan Republic of China Graduate Institute of Applied Physics National Chengchi University Taipei 116011 Taiwan Republic of China

It is important to study the properties of high quality single crystal in order to resolve the issue of an interesting material in which certain debatable fundamental properties exist. However, it is unfortunate that a sizable single crystal for experimental measurements is not always available. NbN is one of the examples; it has attracted scientific and engineering interest due to its diverse physical properties and a variety of structural phases. Until now superconductivity is only observed in cubic δ- and tetragonal γ-NbN but not in hexagonal ɛ-NbN. Recently, Zou et al. reported the observation of superconductivity with Tc∼11.6K in a hexagonal ɛ-NbN based on the measurement on a multiphase powder specimen. In order to resolve the issue, the work used the electron backscattering diffraction technique to characterize phases of micron-size NbN crystals from commercial powders and measure their transport properties. Our results unambiguously confirm that the hexagonal ɛ-NbN phase is not superconducting.

关键词： Electrical conductivity Specific heat Superconductors

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Consistency and variation in the placement of cortical folds: A perspective

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Brain Multiphysics 2023年 5卷

作者： Nagehan Demirci Fatemeh Jafarabadi Xincheng Wang Shuolun Wang Maria A. Holland Bioengineering Graduate Program University of Notre Dame Notre Dame IN 46556 USA Department of Aerospace and Mechanical Engineering University of Notre Dame Notre Dame IN 46556 USA

Cortical folds, known as gyri and sulci, are prominent features of the human brain that play a crucial role in its function. These folds exhibit both consistency and variation within and across individuals and species, presenting a scientific challenge to our understanding of the underlying mechanisms. In this perspective paper, we summarize current knowledge about fold development and placement. We discuss the temporal and anatomical differences between primary, secondary, and tertiary folds, highlighting the consistency of primary folds and the increasing variation in later-developing folds. We explore the biological and mechanical factors that influence fold placement, including gene expression, tissue growth, axonal tension, curvature, thickness, and stiffness, which likely work together in a complex, coupled manner. We also highlight the need for advanced computational modeling approaches to unravel the mechanisms of precise placement of primary folds and further our understanding of brain complexity. Statement of significance: Understanding the factors driving both the consistency and variation in fold patterns is essential for unraveling the functional implications and potential links to neurological and psychiatric disorders. Ultimately, gaining deeper insights into fold development and placement could have significant implications for our fundamental understanding of the brain, as well as mental health research and clinical applications.

关键词： Cortical folding Gyri Sulci Neurodevelopment Comparative neuroanatomy

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Polyzwitterionic Hydrogels for Highly Efficient High Salinity Solar Desalination

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Angewandte Chemie 2022年第36期134卷

作者： Chuxin Lei Weixin Guan Youhong Guo Wen Shi Yuyang Wang Prof. Keith P. Johnston Prof. Guihua Yu Materials Science and Engineering Program and Walker Department of Mechanical Engineering The University of Texas at Austin Austin TX 78712 USA McKetta Department of Chemical Engineering The University of Texas at Austin Austin TX 78712 USA

Interfacial solar vapor generation (SVG) is regarded as a promising and sustainable strategy for clean water production. While many materials have demonstrated excellent evaporation rates under one sun, it remains challenging to design solar evaporators without compromising SVG performance in high-salinity brines (≥10 wt %). Herein, polyzwitterionic hydrogels (PZHs) are proposed as a novel platform for high-salinity solar desalination. Taking advantage of the unique anti-polyelectrolyte effects, PZHs can trap salt ions from the brine water to form a more hydrated polymer network, leading to enhanced SVG performance. PZHs exhibit an exceptional solar evaporation rate of 4.14 kg m −2 h −1 in 10 wt % brine, which is ≈20 % higher than that in pure water. It is anticipated that salt-responsive PZHs may provide insights for the design of next-generation solar desalination systems.

关键词： Anti-Polyelectrolyte Effects Hydration Polyzwitterionic Hydrogel Solar Desalination Solar Vapor Generation

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Bridging particle deformability and collective response in soft solids

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Physical Review Materials 2021年第5期5卷 055605-055605页

作者： John D. Treado Dong Wang Arman Boromand Michael P. Murrell Mark D. Shattuck Corey S. O'Hern Department of Mechanical Engineering & Materials Science Yale University New Haven Connecticut 06520 USA Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut 06520 USA Department of Biomedical Engineering Yale University New Haven Connecticut 06520 USA Department of Physics Yale University New Haven Connecticut 06520 USA Systems Biology Institute Yale University West Haven Connecticut 06516 USA Benjamin Levich Institute and Physics Department The City College of New York New York New York 10031 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA

Soft, amorphous solids such as tissues, foams, and emulsions are composed of deformable particles. However, the effect of single-particle deformability on the collective behavior of soft solids is still poorly understood. We perform numerical simulations of two-dimensional jammed packings of explicitly deformable particles to study the mechanical response of model soft solids. We find that jammed packings of deformable particles with excess shape degrees of freedom possess low-frequency quartic vibrational modes that stabilize the packings even though they possess fewer interparticle contacts than the nominal isostatic value. Adding intraparticle constraints can rigidify the particles, but these particles undergo a buckling transition and gain an effective shape degree of freedom when their preferred perimeter is above a threshold value. We find that the mechanical response of jammed packings of deformable particles with shape degrees of freedom differs significantly from that of jammed packings of rigid-shape particles, which emphasizes the importance of particle deformability in modeling soft solids.

关键词： Collective behavior Jamming Emulsions Foams Tissues Molecular dynamics

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Cortisol AuPd plasmonic unclad POF biosensor

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Biotechnology Reports 2021年 29卷 e00587页

作者： Leitão, Cátia Leal-Junior, Arnaldo Almeida, Ana R. Pereira, Sónia O. Costa, Florinda M. Pinto, João L. Marques, C. i3N Department of Physics University of Aveiro Campus Universitário de Santiago Aveiro 3810-193 Portugal Graduate Program of Electrical Engineering & Mechanical Engineering Department Federal University of Espirito Santo Vitória 29075-910 Brazil

This paper presents the development and feasibility tests of a cortisol immunosensor. The sensor is based on surface plasmon resonance (SPR) using an unclad plastic optical fiber (POF) in which the SPR is used as sensitivity enhancer, promoted by a gold/palladium (AuPd) alloy coating. The AuPd coated fibers were functionalized with an anti-cortisol antibody and passivated with bovine serum albumin (BSA) to be tested in the presence of cortisol as target analyte. The antibody-antigen binding reaction caused a variation of the refractive index on the surface of the AuPd coating, which leads to a shift of the SPR signature wavelength. The sensor was tested for different cortisol concentrations, ranging from 0.005 to 10 ng/mL. The reported biosensor presented a total wavelength shift of 15 nm for the testing range, putting in evidence a high sensitivity. Control tests for selectivity assessment were also performed. Concentrations as high as 10 ng/mL of cortisol, in a sensor functionalized with anti-hCG antibodies, only resulted in 1 nm variation of the resonance wavelength, 15 times lower than the one functionalized with the anti-cortisol antibodies, which indicates a high selectivity for the proposed approach. For this sensing approach the limit of detection (LOD) was determined to be 1 pg/mL. The proposed SPR based POF sensor has a low-cost interrogation method, high sensitivity and low LOD, straightforward signal processing and find important applications in different biological fields. © 2021

关键词： Biosensor Plastic optical fiber SPR Stress monitoring Unclad POF Well-being monitoring

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Design and Control of an Autonomous Robot for Mobility-Impaired Patients

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Journal of Medical robotics Research 2021年第3期6卷

作者： Deb, Aarya Wypych, Zachery Lonner, Jess Ashrafiuon, Hashem Mechanical Engineering Department Villanova University Villanova 19085 PA United States Rothman Orthopaedic Institute Philadelphia 19107 PA United States Ambulatus Robotics Inc. Wynnewood 19096 PA United States

In this paper, a novel autonomous mobile robotic arm is presented that can autonomously follow mobility impaired patients and provide protection against backward and sideway falls. The arm is equipped with a Lidar sensor to estimate the subject distance and orientation for autonomous tracking. An end-effector with is designed to prevent backward and sideway falls when the subject becomes unbalanced. The robot is tested experimentally to demonstrate that it can effectively follow a subject and limit backward and sideway falls. © 2021 World Scientific Publishing Company.

关键词： Lidar guided autonomy Mobile robotic arms mobility aid robots rehabilitation robotics

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Structure of amorphous aluminosilicates obtained from mineral transformation: Potential path for partial remediation of alkaline bauxite residues

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Environmental Advances 2021年 6卷

作者： Bollinger, David L. Erickson, Jessica Stone-Weiss, Nicholas Lere-Adams, Arumala Josiah Karcher, Sam Akin, Idil Deniz McCloy, John S. Materials Science and Engineering Program Washington State University Pullman 99164 WA United States School of Mechanical and Materials Engineering Washington State University Pullman 99164 WA United States Department of Civil and Environmental Engineering Washington State University Pullman 99164 WA United States

Highly alkaline wastes known as bauxite residue are the abundant byproducts of refining bauxite into alumina through the Bayer process, and worldwide estimates of these bauxite residue stockpiles exceed 3 billion tons, with hundreds of millions of tons produced annually. Bauxite residue utilization and remediation are significantly complicated by the presence of recalcitrant minerals that buffer pH, such as sodalite and cancrinite, commonly referred to as desilication products (DSP) in the alumina industry. In this work, a mixture of sodalite (∼52 wt%) and cancrinite (∼30 wt%) was produced using similar conditions to those encountered in some alumina refineries using the Bayer process. These synthetic minerals were then transformed to hydrated aluminosilicates using a simple, low temperature aqueous process. The transformed products were then characterized with X-ray diffraction, infrared spectroscopy, nuclear magnetic resonance, and electron microscopy. Results suggest that a hypothesized conversion to 2:1-type clay minerals was not achieved, but that the materials were ∼79 wt% X-ray amorphous, resembling protoclay-like materials, with silicate network structures and primarily 4-coordinated Al atoms. This was confirmed by independent synthesis and structural comparison with amorphous aluminosilicates based on allophane and imogolite. Water vapor sorption behavior was similar for the synthesized allophane and the converted DSP minerals;∼0.3 g/g sorbed water content. The current process produces highly amorphous aluminosilicate gels with hydraulic properties similar to silica-rich allophane, which have the potential to aid in the remediation of bauxite residue storage facilities. © 2021 The Authors

关键词： Allophane Bauxite Cancrinite Imogolite Protoclays Sodalite

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In vivo investigation of 3D printed polycaprolactone/graphene electro-active bone scaffolds

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Bioprinting 2021年 24卷

作者： Lopes Nalesso, Paulo Roberto Wang, Weiguang Hou, Yanhao Bagne, Leonardo Pereira, Amanda Tavares Helaehil, Julia Venturini Moretti de Andrade, Thiago Antônio Chiarotto, Gabriela Bortolança Bártolo, Paulo Caetano, Guilherme Ferreira Graduate Program in Biomedical Sciences University Centre of Herminio Ometto Foundation Sao Paulo Araras 13607-339 Brazil Department of Mechanical Aerospace and Civil Engineering School of Engineering Faculty of Science and Engineering The University of Manchester Manchester M13 9PL United Kingdom

Additive manufactured scaffolds are widely used as 3D support structures for tissue engineering. This paper investigates the mechanisms behind bone regeneration due to the combined use of 3D printed poly (ϵ-caprolactone)/graphene (PCL/G) electro-active scaffolds and electrical stimulation. A comprehensive in vivo study was conducted to assess the proposed approach, using a rat model. Results show that the combined use of electro-active scaffolds and electrical stimulation therapy accelerates the bone regeneration process and the formation of more organized new bone, through fast angiogenesis, and a rapid transition to the mineralization and bone remodelling phase. The mechanism is investigated and explained. © 2021

关键词： Additive manufacturing Electrical stimulation Electro-active scaffolds Graphene In vivo bone Regeneration Poly(ϵ-caprolactone) Tissue engineering

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Dual Radar: A Multi-modal Dataset with Dual 4D Radar for Autononous Driving

arXiv

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arXiv 2023年

作者： Zhang, Xinyu Wang, Li Chen, Jian Fang, Cheng Yang, Lei Song, Ziying Yang, Guangqi Wang, Yichen Zhang, Xiaofei Li, Jun Li, Zhiwei Yang, Qingshan Zhang, Zhenlin Ge, Shuzhi Sam State Key Laboratory of Automotive Safety and Energy the School of Vehicle and Mobility Ts-inghua University Beijing100084 China School of Mechanical and Electrical Engineering China University of Mining and Technology-Beijing Beijing100083 China School of Artificial Intelligence China University of Mining and Technology-Beijing Beijing100083 China College of Information Science and Technology Beijing University of Chemical Technology Beijing100029 China Beijing Jingwei Hirain Technologies Co. Inc. Beijing100191 China China Automotive Innovation Cooperation Nanjing211113 China Department of Electrical and Computer Engineering Interactive Digital Media Institute Social Robotics Laboratory National University of Singapore Singapore

Radar has stronger adaptability in adverse scenarios for autonomous driving environmental perception compared to widely adopted cameras and LiDARs. Compared with commonly used 3D radars, latest 4D radars have precise vertical resolution and higher point cloud density, making it a highly promising sensor for autonomous driving in complex environmental perception. However, due to the much higher noise than LiDAR, manufacturers choose different filtering strategies, resulting in a direct ratio between point cloud density and noise level. There is still a lack of comparative analysis on which method is beneficial for deep learning-based perception algorithms in autonomous driving. One of the main reasons is that current datasets only adopt one type of 4D radar, making it difficult to compare different 4D radars in the same scene. Therefore, in this paper, we introduce a novel large-scale multi-modal dataset featuring, for the first time, two types of 4D radars captured simultaneously. This dataset enables further research into effective 4D radar perception algorithms. Our dataset consists of 151 consecutive series, most of which last 20 seconds and contain 10,007 meticulously synchronized and annotated frames. Moreover, our dataset captures a variety of challenging driving scenarios, including many road conditions, weather conditions, nighttime and daytime with different lighting intensities and periods. Our dataset annotates consecutive frames, which can be applied to 3D object detection and tracking, and also supports the study of multi-modal tasks. We experimentally validate our dataset, providing valuable results for studying different types of 4D radars. This dataset is released on https://***/adeptthu/Dual-Radar. Copyright © 2023, The Authors. All rights reserved.

关键词： Autonomous vehicles

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A Reflection on Teaching Design Thinking to First-Year engineering Students

A Reflection on Teaching Design Thinking to First-Year Engin...

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2019 IEEE International Conference on engineering, Technology and Education, TALE 2019

作者： Maneeratana, Kuntinee Chancharoen, Ratchatin Thongnuek, Peerapat Sukmuen, Potcharawan Inkaew, Chamaiporn Suwannatthachote, Praweenya Chulalongkorn University Department of Mechanical Engineering Bangkok Thailand Chulalongkorn University Interdisciplinary Program of Biomedical Engineering Thailand Chulalongkorn University Department of Educational Communication and Technology Thailand

ISBN: (纸本)9781728126654

A short ***-style design thinking project was offered to first-year engineering students as an option in an introduction to engineering course. Using the Stanford *** bootcamp bootleg as the guideline, students went through the process - empathy, define, ideate, prototype, and test - very fast with different levels of depth. The works were evaluated using the *** rubric and found to gain limited success. In order to improve the instructional design, the formal developmental study was initiated. Using class observation, focus-group interview and comparison with similar classes, the instructional design was analyzed and weakness identified. The major problems included the student preparation, engagement, participation, core concept understanding as well as active learning activities, technology utilization, feedback and reflection, in short, the class control and facilitation. The instruction design was adjusted with detailed activities such that it would be implemented in the next iteration. © 2019 IEEE.

关键词： Students

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