检索结果-内蒙古大学图书馆

engineering chirality at wafer scale with ordered carbon nanotube architectures

学校读者我要写书评

暂无评论

Nature communications 2023年第1期14卷 7380页

作者： Jacques Doumani Minhan Lou Oliver Dewey Nina Hong Jichao Fan Andrey Baydin Keshav Zahn Yohei Yomogida Kazuhiro Yanagi Matteo Pasquali Riichiro Saito Junichiro Kono Weilu Gao Department of Electrical and Computer Engineering Rice University Houston TX USA. Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA. Department of Electrical and Computer Engineering The University of Utah Salt Lake City UT USA. Carbon Hub Rice University Houston TX USA. Department of Chemical and Biomolecular Engineering Rice University Houston TX USA. J.A. Woollam Co. Inc. Lincoln NE USA. Smalley-Curl Institute Rice University Houston TX USA. Department of Physics Tokyo Metropolitan University Tokyo Japan. Department of Chemistry Rice University Houston TX USA. Department of Materials Science and NanoEngineering Rice University Houston TX USA. Department of Physics Tohoku University Sendai Japan. Department of Physics National Taiwan Normal University Taipei Taiwan. Department of Physics and Astronomy Rice University Houston TX USA. Department of Electrical and Computer Engineering The University of Utah Salt Lake City UT USA. weilu.gao@utah.edu. Carbon Hub Rice University Houston TX USA. weilu.gao@utah.edu.

Creating artificial matter with controllable chirality in a simple and scalable manner brings new opportunities to diverse areas. Here we show two such methods based on controlled vacuum filtration - twist stacking and mechanical rotation - for fabricating wafer-scale chiral architectures of ordered carbon nanotubes (CNTs) with tunable and large circular dichroism (CD). By controlling the stacking angle and handedness in the twist-stacking approach, we maximize the CD response and achieve a high deep-ultraviolet ellipticity of 40 ± 1 mdeg nm. Our theoretical simulations using the transfer matrix method reproduce the experimentally observed CD spectra and further predict that an optimized film of twist-stacked CNTs can exhibit an ellipticity as high as 150 mdeg nm, corresponding to a g factor of 0.22. Furthermore, the mechanical rotation method not only accelerates the fabrication of twisted structures but also produces both chiralities simultaneously in a single sample, in a single run, and in a controllable manner. The created wafer-scale objects represent an alternative type of synthetic chiral matter consisting of ordered quantum wires whose macroscopic properties are governed by nanoscopic electronic signatures and can be used to explore chiral phenomena and develop chiral photonic and optoelectronic devices.

关键词：

Expression of concern: Microchip-based structure determination of low-molecular weight proteins using cryo-electron microscopy

学校读者我要写书评

暂无评论

Nanoscale 2024年第9期16卷 4919页

作者： Michael A Casasanta G M Jonaid Liam Kaylor William Y Luqiu Maria J Solares Mariah L Schroen William J Dearnaley Jarad Wilson Madeline J Dukes Deborah F Kelly Department of Biomedical Engineering Pennsylvania State University University Park PA 16802 USA. Debkelly@psu.edu. Materials Research Institute Pennsylvania State University University Park PA 16802 USA. Bioinformatics and Genomics Graduate Program Huck Institutes of the Life Sciences Pennsylvania State University University Park PA 16802 USA. Molecular Cellular and Integrative Biosciences Graduate Program Huck Institutes of the Life Sciences Pennsylvania State University University Park PA 16802 USA. Department of Electrical and Computer Engineering Duke University Durham NC 27708 USA. RayBiotech Life Peachtree Corners GA 30092 USA. Applications Science Protochips Inc. Morrisville NC 27560 USA.

Expression of concern for 'Microchip-based structure determination of low-molecular weight proteins using cryo-electron microscopy' by Michael A. Casasanta , , 2021, , 7285-7293, https://***/10.1039/D1NR00388G.

关键词：

Terahertz time-domain polarimetry for generalized anistropic and chiral materials 12

学校读者我要写书评

暂无评论

Terahertz time-domain polarimetry for generalized anistropic...

Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XII 2019

作者： Cheng, Gong Choi, Won Jin Jang, Hee-Jeong Kotov, Nicholas A. Norris, Theodore B. Department of Physics University of Michigan Ann ArborMI48109 United States Center for Ultrafast Optical Science University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Department of Chemical Engineering University of Michigan Ann ArborMI48109 United States Biointerfaces Institute University of Michigan Ann ArborMI48109 United States Program in Macromolecular Science and Engineering University of MI Ann ArborMI48109 United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States

ISBN: (纸本)9781510624764

We have developed two terahertz (THz) polarimetric methodologies based on terahertz time-domain spectroscopy (THz-TDS) incorporating three wire-grid polarizers. They require no change to existing THz-TDS setups and are free of any complicated electronic controls and synchronizations. In addition to the standard quantities measured by THz-TDS such as transmission and optical constants, they provide complete information on the anisotropy and chirality for a generalized material through measurements of the full electric field vector and hence the Jones matrix, and calculating specific quantities. Thus terahertz time-domain polarimetry (THz-TDP) can be considered as an upgrade of the conventional THz-TDS, needed for full characterization of anisotropic and chiral materials. In this paper, we describe the details of the experimental settings, mathematical procedures and property quantifications in these methodologies. We present experimental results on an anisotropic polymer sheet showing the effectiveness of the methods, and preliminary data for chiral DNA molecules for the first time in the THz frequency range. © 2019 SPIE.

关键词： Polarimeters

Considerations and recommendations from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 3 — Ex vivo imaging: data processing, comparisons with microscopy, and tractography

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Schilling, Kurt G. Howard, Amy F.D. Grussu, Francesco Ianus, Andrada Hansen, Brian Barrett, Rachel L.C. Aggarwal, Manisha Michielse, Stijn Nasrallah, Fatima Syeda, Warda Wang, Nian Veraart, Jelle Roebroeck, Alard Bagdasarian, Andrew F. Eichner, Cornelius Sepehrband, Farshid Zimmermann, Jan Soustelle, Lucas Bowman, Christien Tendler, Benjamin C. Hertanu, Andreea Jeurissen, Ben Verhoye, Marleen Frydman, Lucio van de Looij, Yohan Hike, David Dunn, Jeff F. Miller, Karla Landman, Bennett A. Shemesh, Noam Anderson, Adam McKinnon, Emilie Farquharson, Shawna Dell' Acqua, Flavio Pierpaoli, Carlo Drobnjak, Ivana Leemans, Alexander Harkins, Kevin D. Descoteaux, Maxime Xu, Duan Huang, Hao Santin, Mathieu D. Grant, Samuel C. Obenaus, Andre Kim, Gene S. Wu, Dan Le Bihan, Denis Blackband, Stephen J. Ciobanu, Luisa Fieremans, Els Bai, Ruiliang Leergaard, Trygve B. Zhang, Jiangyang Dyrby, Tim B. Johnson, G. Allan Cohen-Adad, Julien Budde, Matthew D. Jelescu, Ileana O. Radiology and Radiological Sciences Vanderbilt University Medical Center NashvilleTN United States Vanderbilt University Institute of Imaging Science Vanderbilt University NashvilleTN United States Department of Bioengineering Imperial College London London United Kingdom FMRIB Centre Wellcome Centre for Integrative Neuroimaging Nuffield Department of Clinical Neurosciences University of Oxford Oxford United Kingdom Radiomics Group Vall d’Hebron Institute of Oncology Vall d’Hebron Barcelona Hospital Campus Barcelona Spain Queen Square MS Centre Queen Square Institute of Neurology Faculty of Brain Sciences University College London London United Kingdom Champalimaud Research Champalimaud Foundation Lisbon Portugal Center of Functionally Integrative Neuroscience Aarhus University Aarhus Denmark Department of Neuroimaging Institute of Psychiatry Psychology and Neuroscience King's College London London United Kingdom NatBrainLab Department of Forensics and Neurodevelopmental Sciences Institute of Psychiatry Psychology and Neuroscience King's College London London United Kingdom Russell H. Morgan Department of Radiology and Radiological Science Johns Hopkins University School of Medicine BaltimoreMD United States Maastricht University Medical Center Maastricht Netherlands The Queensland Brain Institute The University of Queensland Queensland Australia Melbourne Neuropsychiatry Centre The University of Melbourne ParkvilleVIC Australia Department of Radiology and Imaging Sciences Indiana University IN United States Stark Neurosciences Research Institute Indiana University School of Medicine IN United States Center for Biomedical Imaging NYU Grossman School of Medicine New YorkNY United States Faculty of psychology and Neuroscience Maastricht University Maastricht Netherlands Department of Chemical & Biomedical Engineering FAMU-FSU College of Engineering Florida State University TallahasseeFL United States Center for Interdisciplinary Magnetic Res

Preclinical diffusion MRI (dMRI) has proven value in methods development and validation, characterizing the biological basis of diffusion phenomena, and comparative anatomy. While dMRI enables in vivo non-invasive characterization of tissue, ex vivo dMRI is increasingly being used to probe tissue microstructure and brain connectivity. Ex vivo dMRI has several experimental advantages that facilitate high spatial resolution and high signal-to-noise ratio (SNR) images, cutting-edge diffusion contrasts, and direct comparison with histological data as a methodological validation. However, there are a number of considerations that must be made when performing ex vivo experiments. The steps from tissue preparation, image acquisition and processing, and interpretation of results are complex, with many decisions that not only differ dramatically from in vivo imaging of small animals, but ultimately affect what questions can be answered using the data. This work concludes a 3-part series of recommendations and considerations for preclinical dMRI. Herein, we describe best practices for dMRI of ex vivo tissue, with a focus on image pre-processing, data processing and model fitting, and tractography. In each section, we attempt to provide guidelines and recommendations, but also highlight areas for which no guidelines exist (and why), and where future work should lie. We end by providing guidelines on code sharing and data sharing, and point towards open-source software and databases specific to small animal and ex vivo imaging. © 2024, CC BY.

关键词： Data Sharing

Coherent growth and characterization of van der Waals 1T-VSe2 layers on GaAs(111)B using molecular beam epitaxy

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Zhu, Tiancong O’Hara, Dante J. Noesges, Brenton A. Zhu, Menglin Repicky, Jacob J. Brenner, Mark R. Brillson, Leonard J. Hwang, Jinwoo Gupta, Jay A. Kawakami, Roland K. Department of Physics Ohio State University ColumbusOH43210 United States Program in Materials Science and Engineering University of California RiversideCA92521 United States Materials Science Division Lawrence Livermore National Laboratory LivermoreCA94550 United States Department of Materials Science and Engineering Ohio State University ColumbusOH43210 United States Department of Electrical and Computer Engineering Ohio State University ColumbusOH43210 United States Semiconductor and Epitaxy Analysis Laboratory Ohio State University ColumbusOH43210 United States

We report epitaxial growth of vanadium diselenide (VSe2) thin films in the octahedrally-coordinated (1T) structure on GaAs(111)B substrates by molecular beam epitaxy. Film thickness from a single monolayer (ML) up to 30 ML is demonstrated. Structural and chemical studies using by x-ray diffraction, transmission electron microscopy, scanning tunneling microscopy and x-ray photoelectron spectroscopy indicate high quality thin films. Further studies show that monolayer VSe2 films on GaAs are not air-stable and are susceptible to oxidation within a matter of hours, which indicates that a protective capping layer should be employed for device applications. This work demonstrates that VSe2, a candidate van der Waals material for possible spintronic and electronic applications, can be integrated with III-V semiconductors via epitaxial growth for 2D/3D hybrid devices. Copyright © 2020, The Authors. All rights reserved.

关键词： Molecular beam epitaxy

Phase imaging with computational specificity (PICS) for measuring dry mass changes in sub-cellular compartments

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Kandel, Mikhail E. He, Yuchen R. Lee, Young Jae Chen, Taylor Hsuan-Yu Sullivan, Kathryn Michele Aydin, Onur Saif, Taher M.A. Kong, Hyunjoon Sobh, Nahil Popescu, Gabriel Beckman Institute University of Illinois at Urbana-Champaign UrbanaIL United States Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Neuroscience Program University of Illinois at Urbana-Champaign UrbanaIL United States Department of Bioengineering University of Illinois at Urbana-Champaign UrbanaIL United States Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Chemical and Biomolecular Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Carl Woese Institute for Genomic Biology University of Illinois at Urbana-Champaign UrbanaIL United States

Due to its specificity, fluorescence microscopy (FM) has become a quintessential imaging tool in cell biology. However, photobleaching, phototoxicity, and related artifacts continue to limit FM’s utility. Recently, it has been shown that artificial intelligence (AI) can transform one form of contrast into another. We present PICS, a combination of quantitative phase imaging and AI, which provides information about unlabeled live cells with high specificity. Our imaging system allows for automatic training, while inference is built into the acquisition software and runs in real-time. Applying the computed fluorescence maps back to the QPI data, we measured the growth of both nuclei and cytoplasm independently, over many days, without loss of viability. Using a QPI method that suppresses multiple scattering, we measured the dry mass content of individual cell nuclei within spheroids. In its current implementation, PICS offers a versatile quantitative technique for continuous simultaneous monitoring of individual cellular components in biological applications where long-term label-free imaging is desirable. Copyright © 2020, The Authors. All rights reserved.

关键词： Fluorescence microscopy

Secure state estimation and control for cyber security of AC microgirds

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Fooladivanda, Dariush Hu, Qie Chang, Young Hwan Sauer, Peter W. Department of Mechanical and Aerospace Engineering University of California San Diego United States Department of Electrical Engineering and Computer Sciences University of California Berkeley United States Department of Biomedical Engineering and Computational Biology Program Oregon Health and Science University United States Department of Electrical and Computer Engineering University of Illinois Urbana-Champaign United States

A timely, accurate, and secure dynamic state estimation is needed for reliable monitoring and efficient control of microgrids. The synchrophasor technology enables us to obtain synchronized measurements in real-time and to develop dynamic state estimators for real-time monitoring and control of microgrids. In this study, we consider an AC microgrid comprising several synchronous generators and inverter-interface power supplies, and focus on securely estimating the dynamic states of the microgrid from a set of corrupted data. We propose a dynamic state estimator which enables the microgrid operator to reconstruct the dynamic states of the microgrid from a set of corrupted data. Finally, we consider an AC microgrid with the same topology as the IEEE 33-bus distribution system, and numerically show that the proposed secure estimation algorithm can accurately reconstruct the attack signals. Copyright © 2019, The Authors. All rights reserved.

关键词： State estimation

Multiscale assay of unlabeled neurite dynamics using phase imaging with computational specificity (PICS)

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Kandel, Mikhail E. Kim, Eunjae Lee, Young Jae Tracy, Gregory Chung, Hee Jung Popescu, Gabriel Beckman Institute University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign UrbanaIL61801 United States Neuroscience Program University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Bioengineering University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Molecular Integrated Physiology University of Illinois at Urbana Champaign UrbanaIL61801 United States

Primary neuronal cultures have been widely used to study neuronal morphology, neurophysiology, neurodegenerative processes, and molecular mechanism of synaptic plasticity underlying learning and memory. Yet, the unique behavioral properties of neurons make them challenging to study - with phenotypic differences expressed as subtle changes in neuronal arborization rather than easy to assay features such as cell count. The need to analyze morphology, growth, and intracellular transport has motivated the development of increasingly sophisticated microscopes and image analysis techniques. Due to its high-contrast, high-specificity output, many assays rely on confocal fluorescence microscopy, genetic methods, or antibody staining techniques. These approaches often limit the ability to measure quantitatively dynamic activity such as intracellular transport and growth. In this work, we describe a method for label-free live-cell cell imaging with antibody staining specificity by estimating the associated fluorescent signals via quantitative phase imaging and deep convolutional neural networks. This computationally inferred fluorescence image is then used to generate a semantic segmentation map, annotating subcellular compartments of live unlabeled neural cultures. These synthetic fluorescence maps were further applied to study the time-lapse development of hippocampal neurons, highlighting the relationships between the cellular dry mass production and the dynamic transport activity within the nucleus and neurites. Our implementation provides a high-throughput strategy to analyze neural network arborization dynamically, with high specificity and without the typical phototoxicity and photobleaching limitations associated with fluorescent markers. Copyright © 2020, The Authors. All rights reserved.

关键词： Fluorescence microscopy

Two-dimensional charge order stabilized in clean polytype heterostructures

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Sung, Suk Hyun Schnitzer, Noah Novakov, Steve El Baggari, Ismail Luo, Xiangpeng Gim, Jiseok Vu, Nguyen M. Li, Zidong Brintlinger, Todd H. Liu, Yu Lu, Wenjian Sun, Yuping Deotare, Parag B. Sun, Kai Zhao, Liuyan Kourkoutis, Lena F. Heron, John T. Hovden, Robert Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering Cornell University IthacaNY14853 United States Kavli Institute at Cornell for Nanoscale Science IthacaNY14853 United States Department of Physics University of Michigan Ann ArborMI48109 United States Department of Physics Cornell University IthacaNY14853 United States Rowland Institute at Harvard CambridgeMA02142 United States Electrical and Computer Engineering Department University of Michigan Ann ArborMI48109 United States Materials Science and Technology Division U.S. Naval Research Laboratory WashingtonDC20375 United States Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei230031 China High Magnetic Field Laboratory Chinese Academy of Sciences Hefei230031 China Collaborative Innovation Centre of Advanced Microstructures Nanjing University Nanjing210093 China Applied Physics Program University of Michigan Ann ArborMI48109 United States School of Applied and Engineering Physics Cornell University IthacaNY14853 United States

Compelling evidence suggests distinct correlated electron behavior may exist only in clean 2D materials such as 1T-TaS2. Unfortunately, experiment and theory suggest that extrinsic disorder in free standing 2D layers disrupts correlation-driven quantum behavior. Here we demonstrate a route to realizing fragile 2D quantum states through endotaxial polytype engineering of van der Waals materials. The true isolation of 2D charge density waves (CDWs) between metallic layers stabilizes commensurate long-range order and lifts the coupling between neighboring CDW layers to restore mirror symmetries via interlayer CDW twinning. The twinned-commensurate charge density wave (tC-CDW) reported herein has a single metal–insulator phase transition at ~350 K as measured structurally and electronically. Fast in-situ transmission electron microscopy and scanned nanobeam diffraction map the formation of tC-CDWs. This work introduces endotaxial polytype engineering of van der Waals materials to access latent 2D ground states distinct from conventional 2D fabrication. © 2021, CC BY.

关键词： Charge density waves