检索结果-内蒙古大学图书馆

The ALCHEMI atlas: principal component analysis reveals starburst evolution in NGC 253

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Harada, Nanase Meier, David S. Martín, Sergio Muller, Sebastien Sakamoto, Kazushi Saito, Toshiki Gorski, Mark D. Henkel, Christian Tanaka, Kunihiko Mangum, Jeffrey G. Aalto, Susanne Aladro, Rebeca Bouvier, Mathilde Colzi, Laura Emig, Kimberly L. Herrero-Illana, Rubén Huang, Ko-Yun Kohno, Kotaro König, Sabine Nakanishi, Kouichiro Nishimura, Yuri Takano, Shuro Rivilla, Víctor M. Viti, Serena Watanabe, Yoshimasa van der Werf, Paul P. Yoshimura, Yuki National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Institute of Astronomy and Astrophysics Academia Sinica 11F of AS/NTU Astronomy-Mathematics Building No.1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Astronomical Science Program Graduate Institute for Advanced Studies SOKENDAI 2-21-1 Osawa Mitaka Tokyo181-1855 Japan New Mexico Institute of Mining and Technology 801 Leroy Place SocorroNM87801 United States National Radio Astronomy Observatory PO Box O 1003 Lopezville Road SocorroNM87801 United States European Southern Observatory Alonso de Córdova 3107 Vitacura Santiago763-0355 Chile Joint ALMA Observatory Alonso de Córdova 3107 Vitacura Santiago763-0355 Chile Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory OnsalaSE-439 92 Sweden Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany Astronomy Department Faculty of Science King Abdulaziz University P. O. Box 80203 Jeddah21589 Saudi Arabia Department of Physics Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kanagawa Yokohama223-8522 Japan National Radio Astronomy Observatory 520 Edgemont Road CharlottesvilleVA22903-2475 United States Department of Space Earth and Environment Chalmers University of Technology GöteborgSE-412 96 Sweden Leiden Observatory Leiden University P.O. Box 9513 Leiden2300 RA Netherlands CSIC-INTA Ctra. de Ajalvir Km. 4 Torrejón de Ardoz Madrid28850 Spain Campus UAB Carrer de Magrans BarcelonaE-08193 Spain Institute of Astronomy Graduate School of Science The University of Tokyo 2-21-1 Osawa Mitaka Tokyo181-0015 Japan Department of Astronomy The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan ALMA Project National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Physic

Molecular lines are powerful diagnostics of the physical and chemical properties of the interstellar medium (ISM). These ISM properties, which affect future star formation, are expected to differ in starburst galaxies from those of more quiescent galaxies. We investigate the ISM properties in the central molecular zone of the nearby starburst galaxy NGC 253 using the ultra-wide millimeter spectral scan survey from the ALMA Large program ALCHEMI. We present an atlas of velocity-integrated images at a 1′′. 6 resolution of 148 unblended transitions from 44 species, including the first extragalactic detection of HCNH+ and the first interferometric images of C3H+, NO, HCS+. We conduct a principal component analysis (PCA) on these images to extract correlated chemical species and to identify key groups of diagnostic transitions. To the best of our knowledge, our dataset is currently the largest astronomical set of molecular lines to which PCA has been applied. The PCA can categorize transitions coming from different physical components in NGC 253 such as i) young starburst tracers characterized by high-excitation transitions of HC3N and complex organic molecules (COMs) versus tracers of on-going star formation (radio recombination lines) and high-excitation transitions of CCH and CN tracing PDRs, ii) tracers of cloud-collision-induced shocks (low-excitation transitions of CH3OH, HNCO, HOCO+, and OCS) versus shocks from star-formation-induced outflows (high-excitation transitions of SiO), as well as iii) outflows showing emission from HOC+, CCH, H3O+, CO isotopologues, HCN, HCO+, CS, and CN. Our findings show these intensities vary with galactic dynamics, star formation activities, and stellar feedback. © 2024, CC BY.

关键词： Principal component analysis

Corrigendum to "Development and functional evaluation of a hyaluronic acid coated nano-formulation with kaempferol as a novel intra-articular agent for knee osteoarthritis treatment"[ Biomed. Pharmacother. 175(2024) 116717]

学校读者我要写书评

暂无评论

Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie 2024年 177卷 116944页

作者： Ching-Yu Lee Yu-Chu Chang Kai-Chiang Yang Yung-Fang Lin Alexander T H Wu Ching-Li Tseng International Ph.D. Program in Cell Therapy and Regenerative Medicine College of Medicine Taipei Medical University Taipei 110301 Taiwan Department of Orthopedics Taipei Medical University Hospital Taipei 110301 Taiwan Department of Orthopaedics School of Medicine College of Medicine Taipei Medical University Taipei 110301 Taiwan Orthopedic Research Center Taipei Medical University Hospital Taipei 110301 Taiwan. Department of Biochemistry and Molecular Cell Biology School of Medicine College of Medicine Taipei Medical University Taipei 110301 Taiwan. School of Dental Technology College of Oral Medicine Taipei Medical University Taipei 110301 Taiwan. Graduate Institute of Biomedical Materials and Tissue Engineering College of Biomedical Engineering Taipei Medical University Taipei 110301 Taiwan International Ph.D. Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University Taipei 110301 Taiwan. The Ph.D. Program for Translational Medicine College of Medical Science and Technology Taipei Medical University Taipei 110301 Taiwan Clinical Research Center Taipei Medical University Hospital Taipei Medical University Taipei 110301 Taiwan. Electronic address: chaw1211@tmu.edu.tw. International Ph.D. Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University Taipei 110301 Taiwan. Electronic address: chingli@tmu.edu.tw.

Effect of Processing Conditions on the Mechanical and Morphological Properties of Elastomeric Poly (Methyl Methacrylate)/Polycarbonate Blends

学校读者我要写书评

暂无评论

Macromolecular Symposia 2019年第1期383卷

作者： de Macedo, Thatiana Cristina Pereira da Silva Reinaldo, Juciklécia Pereira, Laurenice Martins do Rêgo, José Kaio Max Alves Ueki, Marcelo Massayoshi Damasceno, Igor Zumba Ito, Edson Noriyuki Graduate Program in Materials Science and Engineering Federal University of Rio Grande do Norte Avenida Senador Salgado Filho 3000 NatalRN59078-970 Brazil Department of Materials Science and Engineering Federal University of Sergipe Avenida Marechal Rondon São CristóvãoSEs/n 49100-000 Brazil Department of Materials Engineering Federal University of Rio Grande do Norte Avenida Senador Salgado Filho 3000 NatalRN59078-970 Brazil

The aim of this study was to investigate the influence of the processing conditions in single and co-rotational twin screw extruders on the mechanical and morphological properties of elastomeric poly (methyl methacrylate)/polycarbonate (PMMAe/PC) blends until the phase inversion. The characterizations were performed by measuring the melt flow index, capillary rheometry, thermogravimetric analysis, tensile tests, Izod impact, and atomic force microscopy (AFM). The thermal and rheological properties showed that PC had a higher sensitivity to processing conditions than PMMAe. The increase in PC concentration altered the mechanical properties of the PMMAe/PC blends with variations according to processing conditions. The morphology of PMMAe/PC blends up to phase inversion was visualized by AFM, and the results showed that the material processed with a single screw extruder obtained similar morphologies to that material processed in twin screw extruder. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

关键词： Atomic force microscopy

Highly Recyclable and Tough Elastic Vitrimers from a Defined Polydimethylsiloxane Network

学校读者我要写书评

暂无评论

Angewandte Chemie 2023年第47期135卷

作者： Dr. Jiancheng Luo Dr. Xiao Zhao Hao Ju Dr. Xiangjun Chen Dr. Sheng Zhao Dr. Zoriana Demchuk Dr. Bingrui Li Dr. Vera Bocharova Dr. Jan-Michael Y. Carrillo Dr. Jong K. Keum Prof. Sheng Xu Prof. Alexei P. Sokolov Dr. Jiayao Chen Prof. Peng-Fei Cao Chemical Sciences Division Oak Ridge National Laboratory Oak Ridge TN-37830 USA State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Beijing 100029 China Materials Science and Engineering Program University of California San Diego La Jolla CA-92093 USA Department of Chemistry University of Tennessee Knoxville TN-37996 USA The Bredesen Center for Interdisciplinary Research and Graduate Education University of Tennessee Knoxville TN-37996 USA Center for Materials Sciences Oak Ridge National Laboratory Oak Ridge TN-37830 USA Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge TN-37830 USA

Despite intensive research on sustainable elastomers, achieving elastic vitrimers with significantly improved mechanical properties and recyclability remains a scientific challenge. Herein, inspired by the classical elasticity theory, we present a design principle for ultra-tough and highly recyclable elastic vitrimers with a defined network constructed by chemically crosslinking the pre-synthesized disulfide-containing polydimethylsiloxane (PDMS) chains with tetra-arm polyethylene glycol (PEG). The defined network is achieved by the reduced dangling short chains and the relatively uniform molecular weight of network strands. Such elastic vitrimers with the defined network, i.e., PDMS-disulfide-D, exhibit significantly improved mechanical performance than random analogous, previously reported PDMS vitrimers, and even commercial silicone-based thermosets. Moreover, unlike the vitrimers with random network that show obvious loss in mechanical properties after recycling, those with the defined network enable excellent thermal recyclability. The PDMS-disulfide-D also deliver comparable electrochemical signals if utilized as substrates for electromyography sensors after the recycling. The multiple relaxation processes are revealed via a unique physical approach. Multiple techniques are also applied to unravel the microscopic mechanism of the excellent mechanical performance and recyclability of such defined network.

关键词： Defined Network Polydimethylsiloxane Recyclable Polymer Tough Elastomer Vitrimers

Efficient construction method for phase diagrams using uncertainty sampling

学校读者我要写书评

暂无评论

Physical Review materials 2019年第3期3卷 033802-033802页

作者： Kei Terayama Ryo Tamura Yoshitaro Nose Hidenori Hiramatsu Hideo Hosono Yasushi Okuno Koji Tsuda RIKEN Center for Advanced Intelligence Project Tokyo 103-0027 Japan Medical Sciences Innovation Hub Program RIKEN Cluster for Science Technology and Innovation Hub Kanagawa 230-0045 Japan Graduate School of Medicine Kyoto University Kyoto 606-8507 Japan International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science Ibaraki 305-0044 Japan Research and Services Division of Materials Data and Integrated System National Institute for Materials Science Ibaraki 305-0047 Japan Graduate School of Frontier Sciences University of Tokyo Chiba 277-8568 Japan Department of Materials Science and Engineering Kyoto University Kyoto 606-8501 Japan Laboratory for Materials and Structures Institute of Innovative Research Tokyo Institute of Technology Yokohama 226-8503 Japan Materials Research Center for Element Strategy Tokyo Institute of Technology Yokohama 226-8503 Japan

We develop a method to efficiently construct phase diagrams using machine learning. Uncertainty sampling (US) in active learning is utilized to intensively sample around phase boundaries. Here, we demonstrate constructions of three known experimental phase diagrams by the US approach. Compared with random sampling, the US approach decreases the number of sampling points to about 20%. In particular, the reduction rate is pronounced in more complicated phase diagrams. Furthermore, we show that using the US approach, undetected new phases can be rapidly found, and smaller numbers of initial sampling points are sufficient. Thus, we conclude that the US approach is useful to construct complicated phase diagrams from scratch and will be an essential tool in materials science.

关键词： Phase diagrams

Contact network changes in ordered and disordered disk packings

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Tuckman, Philip J. VanderWerf, Kyle Yuan, Ye Zhang, Shiyun Zhang, Jerry Shattuck, Mark D. O’Hern, Corey S. Department of Physics Yale University New HavenCT06520 United States Department of Mechanics and Engineering Science College of Engineering Peking University Beijing100871 China Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department City College of New York New YorkNY10031 United States Department of Physics Yale University Department of Applied New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

We investigate the mechanical response of packings of purely repulsive, frictionless disks to quasistatic deformations. The deformations include simple shear strain at constant packing fraction and at constant pressure, "polydispersity" strain (in which we change the particle size distribution) at constant packing fraction and at constant pressure, and isotropic compression. For each deformation, we show that there are two classes of changes in the interparticle contact networks: jump changes and point changes. Jump changes occur when a contact network becomes mechanically unstable, particles "rearrange", and the potential energy (when the strain is applied at constant packing fraction) or enthalpy (when the strain is applied at constant pressure) and all derivatives are discontinuous. During point changes, a single contact is either added to or removed from the contact network. For repulsive linear spring interactions, second- and higher-order derivatives of the potential energy/enthalpy are discontinuous at a point change, while for Hertzian interactions, third- and higher-order derivatives of the potential energy/enthalpy are discontinuous. We illustrate the importance of point changes by studying the transition from a hexagonal crystal to a disordered crystal induced by applying polydispersity strain. During this transition, the system only undergoes point changes, with no jump changes. We emphasize that one must understand point changes, as well as jump changes, to predict the mechanical properties of jammed packings. Copyright © 2020, The Authors. All rights reserved.

关键词： Potential energy

Effects of TiO 2 waste on the formation of clinker phases and mechanical performance and hydration of Portand cement

学校读者我要写书评

暂无评论

CEMENT 2022年 9卷

作者： José S. Andrade Neto Bruna B. Mariani Nilson S. Amorim Júnior Daniel V. Ribeiro Laboratory of Testing on Materials Durability (LEDMa) / Federal University of Bahia Rua Aristides Novis 02. Federação. 40210-630. Salvador/BA Brazil Post-Graduate Program in Civil Engineering (PPEC) / Federal University of Bahia Aristides Novis 02. Federação. 40210-630. Salvador/BA Brazil Department of Materials Science and Technology / Federal University of Bahia Aristides Novis 02. Federação. 40210-630. Salvador/BA Brazil

The incorporation of different levels of UOW into Portland clinker raw meals and its effects on the clinker and cement properties were evaluated. Clinkers were produced and characterized by X-ray diffractometry (XRD) and optical microscopy; the cements were produced and physically characterized. Finally, pastes were produced and analyzed using isothermal calorimetry, thermogravimetry, XRD, and compressive strength tests. UOW, when added up to 1.29% in Portland clinker raw meal, acts as a mineralizer, increasing the content of alite by 6.44%. The incorporation of UOW reduces the hydration rate in the first days owing to the increase in the size of the alite crystals and delays the point of sulfate depletion due to the increase in the SO 3 content of the clinkers. Owing to the higher content of alite formed, the cement produced from the raw meal with 1.29% of UOW presents the highest early mechanical strength (up to 7 days).

关键词： Portland clinker Unreacted ore waste (UOW) Mineralizer Hydration

Observation of anti-parity-time-symmetry, phase transitions and exceptional points in an optical fibre

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Bergman, Arik Duggan, Robert Sharma, Kavita Tur, Moshe Zadok, Avi Alù, Andrea Faculty of Engineering Institute for Nano-Technology and Advanced Materials Bar-Ilan University Ramat-Gan5290002 Israel Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States School of Electrical Engineering Tel-Aviv University Tel-Aviv6997801 Israel Physics Program Graduate Center City University of New York New YorkNY10026 United States

The exotic physics emerging in non-Hermitian systems with balanced distributions of gain and loss has drawn a great deal of attention in recent years. These systems exhibit phase transitions and exceptional point singularities in their spectra, at which eigen-values and eigen-modes coalesce and the overall dimensionality is reduced. Among several peculiar phenomena observed at exceptional points, an especially intriguing property, with relevant practical potential, consists in the inherently enhanced sensitivity to small-scale perturbations. So far, however, these principles have been implemented at the expenses of precise fabrication and tuning requirements, involving tailored nano-structured devices with controlled distributions of optical gain and loss. In this work, anti-parity-time symmetric phase transitions and exceptional point singularities are demonstrated in a single strand of standard single-mode telecommunication fibre, using a setup consisting of entirely of off-the-shelf components. Two propagating signals are amplified and coupled through stimulated Brillouin scattering, which makes the process non-Hermitian and enables exquisite control over gain and loss. Singular response to small variations around the exceptional point and topological features arising around this singularity are experimentally demonstrated with large precision, enabling robustly enhanced spectral response to small-scale changes in the Brillouin frequency shift. Our findings open exciting opportunities for the exploration of non-Hermitian phenomena over a table-top setup, with straightforward extensions to higher-order Hamiltonians and applications in quantum optics, nanophotonics and sensing. Copyright © 2020, The Authors. All rights reserved.

关键词： Optical fibers

Non-reciprocal interactions induced by water in confinement

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Jiménez-Ángeles, Felipe Harmon, Katherine Nguyen, Trung Dac Fenter, Paul de la Cruz, Monica Olvera Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Applied Physics Graduate Program Northwestern University EvanstonIL60208 United States Department of Chemical and Biological Engineering Northwestern University EvanstonIL60208 United States Chemical Sciences and Engineering Division Argonne National Laboratory LemontIL60439 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States

Water mediates electrostatic interactions via the orientation of its dipoles around ions, molecules, and interfaces. This induced water polarization consequently influences multiple phenomena. In particular, water polarization modulated by nanoconfinement affects ion adsorption and transport, biomolecular self-assembly, and surface chemical reactions. Therefore, it is of paramount importance to understand how water-mediated interactions change at the nanoscale. Here we show that near the graphene surface anion-cation interactions do not obey the translational and isotropic symmetries of Coulomb’s law. We identify a new property, referred to as non-reciprocity, which describes the non-equivalent and directional interaction between two oppositely charged ions near the confining surface when their positions with respect to the interface are exchanged. Specifically, upon exchange of the two ions’ positions along the surface normal direction the interaction energy changes by about 5kBT. In both cases, confinement enhances the attraction between two oppositely charged ions near the graphene surface, while intercalation of one ion into the graphene layers shifts the interaction to repulsive. While the water permittivity in confinement is different from that in bulk, the effects observed here via molecular dynamics simulations and X-ray reflectivity experiments cannot be accounted for by current permittivity models. Our work shows that the water structure is not enough to infer electrostatic interactions near interfaces. Copyright © 2020, The Authors. All rights reserved.

关键词： Ions