检索结果-内蒙古大学图书馆

Transition-Metal Dichalcogenides: Anisotropic Collective Charge Excitations in Quasimetallic 2D Transition-Metal Dichalcogenides (Adv. Sci. 10/2020)

学校读者我要写书评

暂无评论

Advanced science 2020年第10期7卷 2070055-2070055页

作者： Chi Sin Tang Xinmao Yin Ming Yang Di Wu Jing Wu Lai Mun Wong Changjian Li Shi Wun Tong Yung-Huang Chang Fangping Ouyang Yuan Ping Feng Shi Jie Wang Dongzhi Chi Mark B. H. Breese Wenjing Zhang Andrivo Rusydi Andrew T. S. Wee Department of Physics Faculty of Science National University of Singapore S12 Science Drive 3 Singapore 117551 Singapore NUS Graduate School for Integrative Sciences and Engineering National University of Singapore 21 Lower Kent Ridge Singapore 119077 Singapore Singapore Synchrotron Light Source (SSLS) National University of Singapore 5 Research Link Singapore 117603 Singapore Institute of Materials Research and Engineering (IMRE) A*STAR (Agency for Science Technology and Research) 2 Fusionopolis Way Innovis Singapore 138634 Singapore International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology Shenzhen University Shenzhen 518060 China School of Physics and Electronics Central South University No. 932 South Lushan Road Changsha Hunan 410083 China Department of Materials Science & Engineering National University of Singapore 9 Engineering Drive 1 Singapore 117575 Singapore Bachelor Program in Interdisciplinary Studies National Yunlin University of Science and Technology 123 University Road Section 3 Douliou Yunlin 64002 Taiwan

In article number https://***/10.1002/advs.201902726 , Xinmao Yin, Andrew T. S. Wee, and co‐workers observe 1D mid‐IR range anisotropic plasmons in quasi‐metallic WSe 2 and MoS 2 monolayers. In‐depth analysis reveals that the long‐range inter‐chain coupling is responsible for the 1D‐charge dynamics and the plasmon energy is dictated by the effects of spin–orbit coupling. Detailed investigation into these collective modes in 2D‐chained systems opens new opportunities for novel device applications and holds significant implications to the underlying mechanism that governs superconductivity in 2D‐transition‐metal dichalcogenide systems.

关键词： anisotropic charge dynamics phase transitions plasmons spectroscopic ellipsometry transition-metal dichalcogenides

The Alumina Film Nanomorphology Formed to Improve the Corrosion Resistance of Al-2.0 wt% Fe Alloy as Result of the Laser Surface Melting Technique Applied

学校读者我要写书评

暂无评论

Advances in Chemical engineering and science 2017年第1期7卷 10-22页

作者： Moises Meza Pariona Katieli Tives Micene Graduate Program in Engineering and Materials Science State University of Ponta Grossa (UEPG) Ponta Grossa Brazil

The laser surface remelting (LSR) treatment was performed to Al-2.0 wt% Fe alloy with a 2 kW Yb-fiber laser (IPG YLR-2000S). The substrate and laser-treated material characterization were executed using different techniques. Among them, the microstructure was analyzed by optical microscope, SEM, low-angle X-ray diffraction (LAXRD) and the corrosion test was made in aerated solution of 0.1 M H2SO4 at a temperature of 25°C ± 0.5°C. As result was shown, the micrograph of LSR-treated material displaying can be a fine cellular structure and the existence of certain nano-porosities and a similar to a nano-dendritic growth was observed too. The characteristic of melted zone was constituted of metastable phases according to the result of x-rays and the behavior corrosion as a result of the LSR-treated sample, which it was shown to be more resistant to corrosion than the untreated sample. A comparative study was carried out of the cyclic polarization of the laser-treated and untreated samples, demonstrating that the reduction and oxidation reverse peaks were not observed and being the cyclic polarization behavior was of irreversible character in both samples, however, the LSR-treated sample propitious the passivity on the surface also reduced the corrosion phenomena. Wherefore, this type of laser-treated alloy can be applied in the aerospace, aeronautic and automobilist industries.

关键词： Al-2.0 wt% Fe Alloy Laser-Treated Microstructure Low-Angle X-Ray Diffraction Cyclical Polarization

Polycrystalline ZrTe5 Parametrized as a Narrow-Band-Gap Semiconductor for Thermoelectric Performance

学校读者我要写书评

暂无评论

Physical Review Applied 2018年第1期9卷 014025-014025页

作者： Samuel A. Miller Ian Witting Umut Aydemir Lintao Peng Alexander J. E. Rettie Prashun Gorai Duck Young Chung Mercouri G. Kanatzidis Matthew Grayson Vladan Stevanović Eric S. Toberer G. Jeffrey Snyder Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Department of Chemistry Koç University Sariyer Istanbul 34450 Turkey Applied Physics Graduate Program Northwestern University Evanston Illinois 60208 USA Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA National Renewable Energy Laboratory Golden Colorado 80401 USA Department of Metallurgical and Materials Engineering Colorado School of Mines Golden Colorado 80401 USA Department of Chemistry Northwestern University Evanston Illinois 60208 USA Department of Electrical Engineering and Computer Science Northwestern University Evanston Illinois 60208 USA Department of Physics Colorado School of Mines Golden Colorado 80401 USA

The transition-metal pentatellurides HfTe5 and ZrTe5 have been studied for their exotic transport properties with much debate over the transport mechanism, band gap, and cause of the resistivity behavior, including a large low-temperature resistivity peak. Single crystals grown by the chemical-vapor-transport method have shown an n−p transition of the Seebeck coefficient at the same temperature as a peak in the resistivity. We show that behavior similar to that of single crystals can be observed in iodine-doped polycrystalline samples but that undoped polycrystalline samples exhibit drastically different properties: they are p type over the entire temperature range. Additionally, the thermal conductivity for polycrystalline samples is much lower, 1.5 Wm−1 K−1, than previously reported for single crystals. It is found that the polycrystalline ZrTe5 system can be modeled as a simple semiconductor with conduction and valence bands both contributing to transport, separated by a band gap of 20 meV. This model demonstrates to first order that a simple two-band model can explain the transition from n- to p-type behavior and the cause of the anomalous resistivity peak. Combined with the experimental data, the two-band model shows that carrier concentration variation is responsible for differences in behavior between samples. Using the two-band model, the thermoelectric performance at different doping levels is predicted, finding zT=0.2 and 0.1 for p and n type, respectively, at 300 K, and zT=0.23 and 0.32 for p and n type at 600 K. Given the reasonably high zT that is comparable in magnitude for both n and p type, a thermoelectric device with a single compound used for both legs is feasible.

关键词： Band gap Charge density waves Hall effect Semimetals Spin-orbit coupling Thermoelectric effects Chalcogenides Semiconductor compounds

Dynamical charge structure factor of a one-dimensional ionic Hubbard model in the low-energy region

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Komaki, Yuhei Iwase, Yuma Yanagimatsu, Shogo Muta, Yoshiyuki Maeshima, Nobuya Hino, Ken-ichi Doctoral Program in Materials Science Graduate School of Pure and Applied Sciences University of Tsukuba Tsukuba Ibaraki305-8573 Japan College of Engineering Sciences University of Tsukuba Tsukuba305-8573 Japan Center for Computational Sciences University of Tsukuba Tsukuba305-8577 Japan Division of Materials Science University of Tsukuba Tsukuba305-8573 Japan

We present a numerical study of the charge dynamical structure factor N(k, ω) of a one-dimensional (1D) ionic Hubbard model in the Mott insulator (MI) phase. We show that the low-energy spectrum of N(k, ω) is expressed in terms of the spin operators for the spin degrees of freedom. Numerical results for the spin degrees of freedom, obtained by the Lanczos diagonalization method, well reproduce the low-energy spectrum of N(k, ω) of the 1D ionic Hubbard model. In addition, we show that these spectral peaks probe the dispersion of the spin-singlet excitations of the system and are observed in the wide parameter region of the MI phase. Copyright © 2018, The Authors. All rights reserved.

关键词： Numerical methods

Dark-Exciton-Mediated Fano Resonance from a Single Gold Nanostructure Deposited on Monolayer WS2 at Room Temperature

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Wang, Mingsong Wu, Zilong Krasnok, Alex Zhang, Tianyi Liu, Mingzu Liu, He Scarabelli, Leonardo Fang, Jie Liz-Marzán, Luis M. Terrones, Mauricio Alù, Andrea Zheng, Yuebing Department of Mechanical Engineering Materials Science and Engineering Program Texas Materials Institute University of Texas at Austin AustinTX78712 United States Photonics Initiative Advanced Science Research Center Physics Program Graduate Center Department of Electrical Engineering City College of The City University of New York NY10031 United States Department of Materials Science and Engineering Department of Physics Center for 2-Dimensional and Layered Materials Department of Chemistry Pennsylvania State University Pennsylvania State University University ParkPA16802 United States Department of Chemistry and Biochemistry California NanoSystems Institute University of California Los Angeles Los AngelesCA90095 United States Bionanoplasmonics Laboratory CIC biomaGUNE Paseo de Miramón 182 Donostia-San Sebastián20014 Spain Ikerbasque Basque Foundation for Science Bilbao48013 Spain Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine CIBER-BBN Donostia- San Sebastián20014 Spain

Strong spatial confinement and highly reduced dielectric screening provide monolayer transition metal dichalcogenides (TMDCs) with strong many-body effects, thereby possessing optically forbidden excitonic states (i.e., dark excitons) at room temperature. Herein, we explore the interaction of surface plasmons with dark excitons in hybrid systems consisting of stacked gold nanotriangles (AuNTs) and monolayer WS2. We observe a narrow Fano resonance when the hybrid system is surrounded by water, and we attribute the narrowing of the spectral Fano linewidth to the plasmon-enhanced decay of dark K-K excitons. Our results reveal that dark excitons in monolayer WS2 can strongly modify Fano resonances in hybrid plasmon-exciton systems and can be harnessed for novel optical sensors and active nanophotonic devices. Copyright © 2018, The Authors. All rights reserved.

关键词： Gold nanoparticles

Fluorescent phenylthiazoles: Application as latent fingermark and their cytotoxicity against NOK-SI cell line

学校读者我要写书评

暂无评论

Chemical Data Collections 2021年 33卷

作者： Bruno Nunes da Rosa Kristiane de Cássia Mariotti Bruna Silveira Pacheco Caroline Carapina da Silva Neftalí Lenin Villarreal Carreño Caroline Nicolodi Tais Poletti Allison Carlos Assunção Silva Adriana Fernandes da Silva Janice Luehring Giongo Rodrigo de Almeida Vaucher Tiago Franco de Oliveira Claudio Martin Pereira de Pereira Laboratory of Lipidomics and Bioorganic Bioforensics Research Group Federal University of Pelotas 96010 900 Pelotas RS Brazil National Institute of Forensic Science and Technology (INCT Forensic) Porto Alegre (RS) Pelotas (RS) Brazil Identification Group Brazilian Federal Police 90610-093 Porto Alegre RS Brazil Materials Science and Engineering Technology Development Center Federal University of Pelotas 96010-000 Pelotas RS Brazil Post-Graduate Program in Dentistry Department of Restorative Dentistry Dental School Federal University of Pelotas 96010 Pelotas RS Brazil Laboratory of Biochemistry Research and Molecular Biology of Microorganisms (LaPeBBiOM) Federal University of Pelotas 96010-900 Pelotas RS Brazil Pharmacosciences Department Federal University of Health Sciences of Porto Alegre Porto Alegre RS Brazil

Fingerprints are unique to each individual who contributes to human identification in forensic cases. In this sense, the present work aimed to synthesize 1H-pyrazol-1-yl-4-phenylthiazoles and apply them as powder agents to reveal latent finger marks as an alternative and low cost related to powders found on the market. The compounds were characterized by infrared; fluorescence; 1H NMR; 13C NMR; laser diffractometer and SEM. In addition, cytotoxicity was also evaluated in oral keratinocytes showing high cell viability. The result of the hemolytic assay revealed that compound 2a does not present red cell cytotoxicity. The prepared powders were applied to fingermarks deposited on different surfaces providing quality visualization at level three so that human identification is possible.

关键词： Forensic chemistry Fingermark Thiazoles Cytotoxicity Development powder

Computational analysis for the rational design of anti-amyloid beta (Aβ) antibodies

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Greene, D'Artagnan Po, Theodora Pan, Jennifer Tabibian, Tanya Luo, Ray Department of Molecular Biology and Biochemistry University of California IrvineCA92697 United States Chemical and Materials Physics Graduate Program University of California IrvineCA92697 United States Department of Biomedical Engineering University of California IrvineCA92697 United States Department of Chemical Engineering and Materials Science University of California IrvineCA92697 United States

Alzheimer’s Disease (AD) is a neurodegenerative disorder that lacks effective treatment options. Anti-amyloid beta (Aβ) antibodies are the leading drug candidates to treat AD, but the results of clinical trials have been disappointing. Introducing rational mutations into anti-Aβ antibodies to increase their effectiveness is a way forward, but the path to take is unclear. In this study, we demonstrate the use of computational fragment-based docking and MMPBSA binding free energy calculations in the analysis of anti-Aβ antibodies for rational drug design efforts. Our fragment-based docking method successfully predicted the emergence of the common EFRH epitope, MD simulations coupled with MMPBSA binding free energy calculations were used to analyze scenarios described in prior studies, and we introduced rational mutations into PFA1 to improve its calculated binding affinity towards the pE3-Aβ3−8 form of Aβ. Two out of four proposed mutations stabilized binding. Our study demonstrates that a computational approach may lead to an improved drug candidate for AD in the future. Copyright © 2018, The Authors. All rights reserved.

关键词： Antibodies

Analyses of protein cores reveal fundamental differences between solution and crystal structures

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Mei, Zhe Treado, John D. Grigas, Alex T. Levine, Zachary A. Regan, Lynne O'Hern, Corey S. Integrated Graduate Program in Physical & Engineering Biology Yale University New HavenCT06520 United States Department of Chemistry Yale University New HavenCT06520 United States Department of Mechanical Engineering & Materials Science Yale University New HavenCT06520 United States Graduate Program in Computational Biology & Bioinformatics Yale University New HavenCT06520 United States Department of Pathology Yale University New HavenCT06520 United States Department of Molecular Biophysics and Biochemistry Yale University New HavenCT06520 United States Institute of Quantitative Biology Biochemistry and Biotechnology Center for Synthetic and Systems Biology School of Biological Sciences University of Edinburgh Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States

There have been several studies suggesting that protein structures solved by NMR spectroscopy and x-ray crystallography show significant differences. To understand the origin of these differences, we assembled a database of high-quality protein structures solved by both methods. We also find significant differences between NMR and crystal structures|in the root-mean-square deviations of the Cα atomic positions, identities of core amino acids, backbone and sidechain dihedral angles, and packing fraction of core residues. In contrast to prior studies, we identify the physical basis for these differences by modelling protein cores as jammed packings of amino-acid-shaped particles. We find that we can tune the jammed packing fraction by varying the degree of thermalization used to generate the packings. For an athermal protocol, we find that the average jammed packing fraction is identical to that observed in the cores of protein structures solved by x-ray crystallography. In contrast, highly thermalized packing-generation protocols yield jammed packing fractions that are even higher than those observed in NMR structures. These results indicate that thermalized systems can pack more densely than athermal systems, which suggests a physical basis for the structural differences between protein structures solved by NMR and x-ray crystallography. Copyright © 2019, The Authors. All rights reserved.

关键词： X ray crystallography

Vectorial Holograms: Full‐Color Complex‐Amplitude Vectorial Holograms Based on Multi‐Freedom Metasurfaces (Adv. Funct. Mater. 21/2020)

学校读者我要写书评

暂无评论

Advanced Functional materials 2020年第21期30卷

作者： Zi‐Lan Deng Mingke Jin Xuan Ye Shuai Wang Tan Shi Junhong Deng Ningbin Mao Yaoyu Cao Bai‐Ou Guan Andrea Alù Guixin Li Xiangping Li Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics Technology Jinan University Guangzhou 510632 P. R. China Department of Materials Science and Engineering Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen 518055 P. R. China Photonics Initiative Advanced Science Research Center City University of New York 85 St. Nicholas Terrace New York NY 10031 USA Physics Program The Graduate Center City University of New York 365 Fifth Avenue New York NY 10016 USA Department of Electrical Engineering City College of New York New York NY 10031 USA