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arXiv 2023年

作者： Doumani, Jacques Lou, Minhan Dewey, Oliver Hong, Nina Fan, Jichao Baydin, Andrey Yomogida, Yohei Yanagi, Kazuhiro Pasquali, Matteo Saito, Riichiro Kono, Junichiro Gao, Weilu Department of Electrical and Computer Engineering Rice University HoustonTX United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX United States Department of Electrical and Computer Engineering The University of Utah Salt Lake CityUT United States Carbon Hub Rice University HoustonTX United States Department of Chemical and Biomolecular Engineering Rice University HoustonTX United States J.A. Woollam Co. Inc. LincolnNE United States Smalley–Curl Institute Rice University HoustonTX United States Department of Physics Tokyo Metropolitan University Tokyo Japan Department of Chemistry Rice University HoustonTX United States Department of Materials Science and NanoEngineering Rice University HoustonTX United States Department of Physics Tohoku University Sendai Japan Department Physics and Astronomy Rice University HoustonTX United States

There is an emerging recognition that successful utilization of chiral degrees of freedom can bring new scientific and technological opportunities to diverse research areas. Hence, methods are being sought for creating artificial matter with controllable chirality in an uncomplicated and reproducible manner. Here, we report the development of two straightforward methods for fabricating wafer-scale chiral architectures of ordered carbon nanotubes (CNTs) with tunable and giant circular dichroism (CD). Both methods employ simple approaches, (i) mechanical rotation and (ii) twist-stacking, based on controlled vacuum filtration and do not involve any sophisticated nanofabrication processes. We used a racemic mixture of CNTs as the starting material, so the intrinsic chirality of chiral CNTs is not responsible for the observed chirality. In particular, by controlling the stacking angle and handedness in (ii), we were able to maximize the CD response and achieve a record-high deep-ultraviolet ellipticity of 40 ± 1 mdeg/nm. Our theoretical simulations using the transfer matrix method reproduce the salient features of the experimentally observed CD spectra and further predict that a film of twist-stacked CNTs with an optimized thickness will exhibit an ellipticity as high as 150 mdeg/nm. The created wafer-scale objects represent a new class of synthetic chiral matter consisting of ordered quantum wires whose macroscopic properties are governed by nanoscopic electronic signatures such as van Hove singularities. These artificial structures with engineered chirality will not only provide playgrounds for uncovering new chiral phenomena but also open up new opportunities for developing high-performance chiral photonic and optoelectronic devices. © 2023, CC BY.

关键词： Carbon nanotubes

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THz Emission from Exchange-Coupled Fe/Ru/Ni Spintronic Emitters

THz Emission from Exchange-Coupled Fe/Ru/Ni Spintronic Emitt...

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International Conference on Infrared and Millimeter Waves

作者： R. Adam C. Greb D. E. Bürgler D. Cao S. Heidtfeld F. Wang J. Cheng D. Chakraborty I. Komissarov H. Hardtdegen M. Mikulics M. Büscher C. M. Schneider Roman Sobolewski Research Centre Jülich Peter Grünberg Institute (PGI-6) Jülich Germany Institut für Laser- und Plasmaphysik Heinrich Heine Universität Düsseldorf Düsseldorf Germany College of Physics Center for Marine Observation and Communications Qingdao University Qingdao China Materials Science Graduate Program University of Rochester Rochester New York USA Laboratory for Laser Energetics University of Rochester Rochester New York USA Department of Electrical and Computer Engineering University of Rochester Rochester New York USA Research Centre Jülich Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons Jülich Germany Faculty of Physics University Duisburg-Essen Duisburg Germany Department of Physics University of California Davis Davis California USA

We explored THz emission from $\mathrm{Si}^{2} / \mathrm{SiO}_{2} / / \mathrm{Ta} / \mathrm{Fe} / \mathrm{Ru} /$ $\mathrm{Ni} / \mathrm{Al}_{2} \mathrm{O}_{3}$ spintronic emitters. We tuned magnetization alignment of Fe and Ni layers by varying the interlayer exchange coupling (IEC) strength using a range of Ru layer thickness t. Depending on IEC strength, magnetization hysteresis shows either ferromagnetic $(t=1.1 \mathrm{~nm}, 1.5 \mathrm{~nm})$, antiferromagnetic $(t=1.3 \mathrm{~nm})$ or canted $(t=1.7 \mathrm{~nm}, 1.9 \mathrm{~nm})$ relative alignment. Competition between IEC and an external magnetic field results in a dramatic difference in THz emission from the ferromagnetically (FM) and anti-ferromagnetically (AFM) coupled structures. The resulting THz emission from IEC structures is a result of an interference of THz transiens generated by the individual $\mathrm{Fe} / \mathrm{Ru}$ and $\mathrm{Ru} / \mathrm{Ni}$ emitters.

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Development of a Selective Wet-Chemical Etchant for 3D Structuring of Silicon via Nonlinear Laser Lithography

arXiv

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arXiv 2023年

作者： Borra, Mona Zolfaghari Radfar, Behrad Nasser, Hisham Çolakoğlu, Tahir Tokel, Onur Turnalı, Ahmet Demirtaş, Merve Ustunel, Hande Toffoli, Daniele Ömer İlday, F. Turan, Raşit Pavlov, Ihor Bek, Alpan ODTÜ-GÜNAM Middle East Technical University Ankara06800 Turkey Ankara06800 Turkey Department of Electronics and Nanoengineering Aalto University Tietotie 3 EspooFI-02150 Finland Department of Physics Engineering Ankara University Ankara06100 Turkey Department of Physics Bilkent University Ankara06800 Turkey UNAM National Nanotechnology Research Center Institute of Materials Science and Nanotechnology Bilkent University Ankara06800 Turkey Department of Electrical and Electronics Engineering Bilkent University Ankara06800 Turkey Department of Electrical and Computer Engineering Boston University 8 Saint Mary’s Street BostonMA02215 United States Ankara06800 Turkey Network Technologies Department TUBITAK ULAKBIM Ankara06800 Turkey Department of Chemical and Pharmaceutical Sciences Trieste University Trieste Italy IOM-CNR Istituto Officina dei Materiali Trieste34149 Italy Micro and Nanotechnology Graduate Program of Natural and Applied Sciences Middle East Technical Turkey

Recently-demonstrated high-quality three-dimensional (3D) subsurface laser processing inside crystalline silicon (c-Si) wafers opens a door to a wide range of novel applications in multidisciplinary research areas. Using this technique, a novel maskless micro-pillars with precise control on the surface reflection and coverage are successfully fabricated by etching the laser processed region of c-Si wafer. To achieve this, a particular selective wet chemical etching is developed to follow subsurface laser processing of c-Si to reveal the desired 3D structures with smooth surfaces. Here, we report the development of a novel chromium-free chemical etching recipe based on copper nitrate, which yields substantially smooth surfaces at high etch rate and selectivity on the both laser-processed Si surface and subsurface, i.e., without significant etching of the unmodified Si. Our results show that the etch rate and surface morphology are interrelated and strongly influenced by the composition of the adopted etching solution. After an extensive compositional study performed at room temperature, we identify an etchant with a selectivity of over 1600 times for laser-modified Si with respect to unmodified Si. We also support our findings using density functional theory calculations of HF and Cu adsorption energies, indicating significant diversity on the c-Si and laser-modified surfaces. Copyright © 2023, The Authors. All rights reserved.

关键词： Morphology

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Influence of Dentin Priming with Tannin-Rich Plant Extracts on the Longevity of Bonded Composite Restorations

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Scientific World Journal 2021年第1期2021卷 1614643页

作者： Polassi, Mackeler Ramos Oliveira, Thales De Sá Carvalho, Ana Calheiros De Medeiros, Lívia Soman De Medeiros Veiga, Thiago André Moura Graeff, Carlos Frederico De Oliveira González, Alejandra Hortencia Miranda Marcucci, Maria Cristina Grecco, Simone Dos Santos Dalpino, Paulo Henrique Perlatti Universidade Anhanguera de São Paulo São Paulo Brazil Department of Chemistry Universidade Federal de São Paulo SP Diadema Brazil São Paulo State University (UNESP) School of Sciences POSMAT - Post-Graduate Program in Materials Science and Technology SP Bauru Brazil Triplet Biotechnology Solutions São Paulo Brazil Science and Technology Institute Universidade Estadual Paulista - UNESP SP São José dos Campos Brazil

Objective. This in vitro study evaluated the influence of bioactive plant extracts as dentin biomodifying agents to improve the longevity of bonded restorations. For that, plant extracts were applied to the dentin surface prior to the adhesive system. materials and Methods. Bovine incisors were ground flat to obtain 2 mm thick slices in which conical preparations were made (N = 10). Tannin-containing plant extracts were applied to dentin before the application of the restorative system, as follows: control group (untreated, CTL), chlorhexidine 0.12% (CHX), mastruz (Dysphania ambrosioides, MTZ), cat's claw (Uncaria tomentosa, CTC), guarana (Paullinia cupana, GUA), galla chinensis (Rhus chinensis, GCH), and tannic acid (extracted from Acacia decurrens, TNA). The push-out bond strength test was conducted (0.5 mm/min). Dentin biomodification was assessed by the modulus of elasticity and mass change in bovine tooth sections (0.5 × 1.7 × 7.0 mm). The dentin staining after extract treatments of dentin slices was compared. The dentin surface wettability was also evaluated by means of the contact angles of the adhesive system with the dentin surface and compared with the untreated control group. Data were subjected to ANOVA/Tukey's test (α = 0.05). Results. The bond strength of the restoratives to dentin was not significantly improved by the plant extracts, irrespective of the evaluation time (p>0.05). Except for TNA, the elastic modulus of demineralized dentin significantly reduced after treatment with the plant extracts (p<0.05). The dentin staining correlated with the tannin content of the extracts. The contact angle was significantly reduced when treated with CTC, GCH, and TNA. Conclusions. The tannin-containing extracts had a questionable effect on the longevity of bonded restorations. The dentin modulus was negatively affected by the extract treatments. Although some of the extracts changed the contact angle, which seems to improve the adhesive monomer permeation, the

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Topology of three-dimensional Dirac semimetals and generalized quantum spin Hall systems without gapless edge modes

arXiv

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arXiv 2020年

作者： Tyner, Alexander C. Sur, Shouvik Puggioni, Danilo Rondinelli, James M. Goswami, Pallab Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Department of Materials Science and Engineering Northwestern University IL60208 United States Northwestern Argonne Institute for Science and Engineering EvanstonIL60208 United States

Usually the quantum spin Hall states are expected to possess gapless, helical edge modes. Are there clean, non-interacting, quantum spin Hall states without gapless, edge modes? We show the generic, n-fold-symmetric, momentum planes of three-dimensional, stable Dirac semi-metals, which are orthogonal to the direction of nodal separation are examples of such generalized quantum spin Hall systems. We demonstrate that the planes lying between two Dirac points and the celebrated Bernevig-Zhang-Hughes model support identical quantized, non-Abelian Berry flux of magnitude 2π. Consequently, both systems exhibit spin-charge separation in response to electromagnetic, π-flux vortex. The Dirac points are identified as the unit-strength, monopoles of SO(5) Berry connections, describing topological quantum phase transitions between generalized, quantum spin Hall and trivial insulators. Our work identifies precise bulk invariant and quantized response of Dirac semimetals and shows that many two-dimensional higher-order topological insulators can be understood as generalized quantum spin Hall systems, possessing gapped edge states. Copyright © 2020, The Authors. All rights reserved.

关键词： Fruits

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A genuine correlation in piezoelectric properties of two-dimensional materials: A high-throughput computational study

arXiv

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arXiv 2020年

作者： Arlı, Cihan Kocabaş, Tugbey Çakır, Deniz Sevik, Cem Department of Materials Science and Engineering Institute of Graduate Program Eskisehir Technical University Eskiehir TR26555 Turkey Department of Physics and Astrophysics University of North Dakota Grand ForksND58202 United States Department of Mechanical Engineering Faculty of Engineering Eskisehir Technical University Eskiehir TR26555 Turkey

The rational design of two-dimensional piezoelectric materials has recently garnered increasing interest because of harnessing these materials in technological applications, including sensor technology, actuating devices, energy harvesting, and medical applications. Several materials possessing high piezoelectric response have been reported so far, but a high-throughput first-principles approach to estimate the piezoelectric potential of layered materials has not been performed yet. In this respect, we systematically investigated the piezoelectric (e11, d11) and elastic (C11 and C12) properties of 108 thermodynamically stable two-dimensional (2D) semiconductor materials by employing first-principle methods. Our calculations found a notable difference between the relaxed ion coefficients calculated with GGA and LDA functionals, indicating a strong exchange-correlation functional dependence. Nevertheless, both functionals yield the same trends for the elastic constants and piezoelectric coefficients. Our high-throughput approach demonstrates that the materials containing Group-V elements produce notably high piezoelectric strain constants, d11 > 40 pmV−1, and 42 of considered materials have the e11 coefficient higher than MoS2 insomuch as BrSSb has one of the largest d11 with a value of 503.6 pmV−1. Besides, we established simple empirical models to estimate the d11 coefficients by utilizing the relative ionic motion in the unit cell and the polarizability of the individual elements in the compounds. The proposed models, tested for both exchange-correlation functionals, are successful in estimating the piezoelectric constants of the studied materials with sufficient accuracy. Copyright © 2020, The Authors. All rights reserved.

关键词： Piezoelectricity

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Retraction notice to "Personal protective equipment-derived pollution during Covid-19 era: A critical review of ecotoxicology impacts, intervention strategies, and future challenges" [Sci. Total Environ. 887(2023) 164164]

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The science of the total environment 2025年 967卷 178758页

作者： Mehedi Hasan Abu Reza Md Towfiqul Islam Most Mastura Munia Farjana Jion Md Naimur Rahman Susmita Datta Peu Arnob Das A B M Mainul Bari Md Saiful Islam Subodh Chandra Pal Aznarul Islam Tasrina Rabia Choudhury Md Refat Jahan Rakib Abubakr M Idris Guilherme Malafaia Department of Disaster Management Begum Rokeya University Rangpur 5400 Bangladesh. Department of Disaster Management Begum Rokeya University Rangpur 5400 Bangladesh Department of Development Studies Daffodil International University Dhaka 1216 Bangladesh. Department of Geography and Environmental Science Begum Rokeya University Rangpur 5400 Bangladesh. Department of Agriculture Hajee Mohammad Danesh Science and Technology University Dinajpur 5200 Bangladesh. Department of Mechanical Engineering Rajshahi University of Engineering & Technology 6 Rajshahi 6204 Bangladesh. Department of Industrial and Production Engineering Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh. Department of Soil Science Patuakhali Science and Technology University Dumki Patuakhali 8602 Bangladesh. Department of Geography The University of Burdwan Bardhaman 713104 West Bengal India. Department of Geography Aliah University 17 Gorachand Road Kolkata 700 014 West Bengal India. Analytical Chemistry Laboratory Chemistry Division Atomic Energy Centre Dhaka (AECD) Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh. Department of Fisheries and Marine Science Faculty of Science Noakhali Science and Technology University Noakhali Bangladesh. Department of Chemistry College of Science King Khalid University Abha 62529 Saudi Arabia Research Center for Advanced Materials Science (RCAMS) King Khalid University Abha Saudi Arabia. Post-Graduation Program in Conservation of Cerrado Natural Resources Goiano Federal Institute Urutaí GO Brazil Post-Graduation Program in Ecology Conservation and Biodiversity Federal University of Uberlândia Uberlândia MG Brazil Post-Graduation Program in Biotechnology and Biodiversity Federal University of Goiás Goiânia GO Brazil.

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Double affinity ligands modified graphene enabled orientation-controllable cryo-EM sample preparation

Double affinity ligands modified graphene enabled orientatio...

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第七届全国冷冻电子显微学与结构生物学专题研讨会

作者：程航 Liming Zheng Nan Liu Jie Xu Congyuan Huang Ye Lu Hailin Peng Yanan Chen Hong-Wei Wang Ministry of Education Key Laboratory of Protein Sciences Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua University Tsinghua-Peking Joint Center for Life Sciences Tsinghua University Center for Nanochemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking University Joint Graduate Program of Peking-Tsinghua-NIBS School of Life SciencesTsinghua University Academy for Advanced Interdisciplinary Studies Peking University School of Materials Science and Engineering Tianjin University Beijing Frontier Research Center for Biological Structures Tsinghua University

With the development of both hardwares and softwares of cryo-electron microscopy (cryo-EM),high- resolution structures of macromolecules have been increasingly ***,the robustness and generality of this technique are severely challenged by the air-water interface and preferred orientation issues during specimen preparation,which practically take plenty of efforts to overcome,especially for those hard *** we reported double-modified graphene (DMG) as the supporting material in cryo-EM sample preparation by covalently modified graphene membrane with two different affinity ligands,

关键词： DMG Double affinity ligands modified graphene enabled orientation-controllable cryo-EM sample preparation

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Physical characteristics of modified cassava flour wastewater at room temperature

Physical characteristics of modified cassava flour wastewate...

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International Conference on Food science and Technology 2018, ICFST 2018

作者： Yaqin, N. Al-Baarri, A.N. Legowo, A.M. Widayat Budihardjo, M.A. Program of Environmental Science School of Post-Graduate Studies Diponegoro University Semarang Indonesia Food Technology Department Faculty of Animal and Agricultural Sciences Diponegoro University Semarang Indonesia Chemical Engineering Department Faculty of Engineering Diponegoro University Semarang Indonesia Center of Research and Services Diponegoro University Semarang Indonesia Department of Environmental Engineering Faculty of Engineering Diponegoro University Indonesia

Cassava is an agricultural material that is considered as important raw resources in the industrial sector. The benefits are even greater after being modified using lactic acid bacteria. However, the mocaf industry often causes water and air pollution. Environmental problems arise after the fermentation process. Determination problems with lightness, TDS (Total Dissolved Solid), conductivity and pH analysis are required to measure the impact to the environment. This research was used waste water from mocaf during 3 days fermentation. The wastewater had the highest color level (Lightness) on initial day of fermentation at 83.7±3.73 and then decrease along the day of fermentation at the averages of 65.2±2.0. The highest TDS was resulted from the mocaf wastewater at a value of 1218 ± 4.6 ppm which continued to decline until day 4. The conductivity and pH showed a decrease along the day of fermentation. As conclusion, physical characteristic of wastewater from mocaf production could be analyzed specifically and determined through color, TDS, conductivity, and pH. © 2019 Published under licence by IOP Publishing Ltd.

关键词： Fermentation

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Alternation of Magnetic Anisotropy Accompanied by Metal-Insulator Transition in Strained Ultrathin Manganite Heterostructures

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Physical Review Applied 2021年第6期15卷 064019-064019页

作者： Masaki Kobayashi Le Duc Anh Masahiro Suzuki Shingo Kaneta-Takada Yukiharu Takeda Shin-ichi Fujimori Goro Shibata Arata Tanaka Masaaki Tanaka Shinobu Ohya Atsushi Fujimori Department of Electrical Engineering and Information Systems The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Center for Spintronics Research Network The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Institute of Engineering Innovation Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan PRESTO JST 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan Department of Physics The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Materials Sciences Research Center Japan Atomic Energy Agency Sayo-gun Hyogo 679-5148 Japan Department of Applied Physics Tokyo University of Science Katsushika Tokyo 125-8585 Japan Quantum Matter Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima 739-8530 Japan Department of Applied Physics Waseda University Okubo Shinjuku Tokyo 169-8555 Japan

A fundamental understanding of the interfacial magnetic properties in ferromagnetic heterostructures is essential for utilizing ferromagnetic materials for spintronic device applications. Here, we investigate the interfacial magnetic and electronic structures of epitaxial single-crystalline LaAlO3(LAO)/La0.6Sr0.4MnO3(LSMO)/Nb:SrTiO3(Nb:STO) heterostructures with varying LSMO layer thicknesses, in which the magnetic anisotropy strongly changes with the LSMO thickness due to the delicate balance between strains originating from both the Nb:STO and LAO layers, using x-ray magnetic circular dichroism and photoemission spectroscopy. We successfully detect the clear change of the magnetic behavior of the Mn ions concomitant with the thickness-dependent metal-insulator transition. Our results suggest that the double-exchange interaction induces ferromagnetism in the metallic LSMO film under tensile strain caused by the STO substrate, while the superexchange interaction determines the magnetic behavior in the insulating LSMO film under compressive strain originating from the top LAO layer. The change in strain, depending on LSMO layer thickness, is confirmed by scanning transmission electron microscopy. Based on those findings, the formation of a magnetic dead layer near the LAO/LSMO interface is attributed to competition between the superexchange interaction via Mn 3d3z2−r2 orbitals under compressive strain and the double-exchange interaction via the 3dx2−y2 orbitals. These findings provide key aspects of ferromagnetic oxide heterostructures for the development of spintronic device applications.

关键词： Electronic structure Ferromagnetism Magnetic anisotropy Metal-insulator transition Spintronics Transition metal oxides Photoemission spectroscopy X-ray magnetic circular dichroism

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