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Block Copolymer Thin Films Above and Below the Order-Disorder Transition Temperature

MRS Online Proceedings Library 2011年第1期629卷 1-6页

作者： Ratchana Limary Peter F. Green Dept. of Chemical Engineering and the Graduate Program in Materials Science The University of Texas at Austin Austin USA

Symmetric diblock copolymers undergo a disorder to order transition below a microphase separation transition temperature. In this temperature range the structure is characterized by alternating lamellae of thickness L. In thin film geometries, the lamellae are oriented normal to the substrate if there is a preferential interaction between either of the block constituents and the substrate/copolymer or copolymer/vacuum interfaces. Depending on the relation between the film thickness and L, the topography of the film might comprise of holes, islands or spinodal-like structures. We show that in a polystyrene-b-poly(methyl methacrylate) diblock copolymer of molecular weight 20, 000 g/mol, above the microphase separation transition temperature, the topography of the film depends on the thickness. A heirarchy of bicontinuous patterns and holes is observed with increasing film thickness for films thinner than 35 nm.

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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

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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

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Analysis of A 2D cathodic protection system for a buried slender structure with the dual boundary element method

Analysis of A 2D cathodic protection system for a buried sle...

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European Congress on Computational Methods in Applied sciences and engineering, ECCOMAS 2004

作者： De Lacerda, Luiz A. De Oliveira, Paulo A. Lázaris, José Da Silva, José M. LACTEC - Institute of Technology for Development Materials Department Centro Politécnico Cx. P. 19067 Curitiba Brazil PPGMNE - Post-Graduate Program on Numerical Methods in Engineering UFPR - Federal University of Paraná Curitiba Brazil

In this paper a boundary element formulation is developed and used for the analysis of cathodic protection systems of buried slender structures, such as foundations of electric transmission line towers. The foundation is basically a truss structure and the slenderness of the pieces composing it, brings numerical difficulties into the classical boundary element method. To avoid this problem, the dual boundary element method is implemented: combination of standard and hypersingular integral equations to form a mathematically well-posed system. A simple experiment is carried out where a galvanized metallic sheet is buried alongside two Copper electrodes (anodes) in parallel, with the objective of simulating a two-dimensional problem. The soil resistivity properties are measured along the depth and the non-linear polarization curves describing the relation between the current density and the electrochemical potential at the metallic sheet is investigated. Two situations are analysed: a) current is injected into the ground through both electrodes;b) current is injected through only one of the electrodes. In the numerical implementation, the soil is modeled as a homogeneous layered half-space with a different property for each layer. The validity of the proposed dual approach is discussed and compared with the measurements of potential at the ground surface.

关键词： Boundary element method

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Effect of Surface Roughness on the Magnetism, Nano-indentation, Surface Energy, and Electrical Properties of Co60Fe20Dy20 Films on Si (100) Substrate

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Journal of Electronic materials 2024年第4期53卷 1752-1762页

作者： Liu, Wen-Jen Chang, Yung-Huang Chiang, Chia-Chin Chen, Yuan-Tsung Lin, Chih-Chien Chen, Pei-Ling Lin, Shih-Hung Department of Materials Science and Engineering I-Shou University Kaohsiung840 Taiwan Bachelor Program in Industrial Technology National Yunlin University of Science and Technology 123 University Road Section 3 Yunlin Douliou64002 Taiwan Department of Mechanical Engineering National Kaohsiung University of Science and Technology Kaohsiung City80778 Taiwan Graduate School of Materials Science National Yunlin University of Science and Technology 123 University Road Section 3 Yunlin Douliou64002 Taiwan Department of Electronic Engineering National Yunlin University of Science and Technology 123 University Road Section 3 Yunlin Douliou64002 Taiwan

In this study, we focused on depositing a target material, cobalt-iron-dysprosium (Co60Fe20Dy20), onto silicon (Si) (100) substrates with thickness varying from 10 nm to 50 nm through a direct-current (DC) magnetron sputtering technique. The subsequent step involved subjecting the samples to an hour-long annealing process in a vacuum annealing furnace at temperatures of 100°C, 200°C, and 300°C. To assess the elemental composition of the CoFeDy films, energy-dispersive X-ray spectroscopy (EDS) was employed. An observed trend indicated an increase in low-frequency alternating-current magnetic susceptibility (χac) with the increasing thickness. Remarkably, the CoFeDy films exhibited their peak χac following annealing at 300°C, with an optimal resonance frequency of 50 Hz. After annealing at 300°C, the CoFeDy film’s surface energy peaked at 50 nm. The magnetic, electrical, and adhesive properties of the CoFeDy films were notably influenced by surface roughness at different annealing temperatures. Atomic force microscopy (AFM) analysis revealed a gradual reduction in film roughness post-annealing, corresponding to smoother surfaces indicative of a weaker domain wall pinning effect, heightened carrier conductivity, and increased liquid spreading. Collectively, these outcomes contributed to diminished χac, reduced electrical resistance, and enhanced adhesion. Graphical Abstract: (Figure presented.) © The Minerals, Metals & materials Society 2024.

关键词： Adhesion

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On-Chip Perovskite Nanocrystal Laser Integrated with Long-Range Surface Plasmon Polariton Waveguide by Etching-Free Lithographic Patterning

On-Chip Perovskite Nanocrystal Laser Integrated with Long-Ra...

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2022 JSAP-Optica Joint Symposia, JSAP 2022

作者： Lee, Yang-Chun Lin, Hsin-Chang Lin, Cheng-Chieh Ho, Ya-Lun Xing, Di Chen, Mu-Hsin Lin, Bo-Wei Chen, Li-Yin Chen, Chun-Wei Delaunay, Jean-Jacques School of Engineering The University of Tokyo Japan Department of Photonics National Sun Yat-sen University Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Academia Sinica Taiwan Department of Materials Science and Engineering National Taiwan University Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taiwan Department of Photonics National Yang Ming Chiao Tung University Taiwan Center of Atomic Initiative for New Materials National Taiwan University Taiwan

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Evaluation of Single and Duplex Plasma Treatment Applied to Aisi 409 Stainless Steel

SSRN

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SSRN 2024年

作者： do Monte e Silva, André Felipe Soares de Almeida, Larissa Solano Monteiro, Leandro Rossino, Luciana Sgarbi Nunes, Maelson Sousa Libório, Maxwell Santana de Carvalho Costa, Thércio Henrique Bandeira, Rafael Marinho de Sousa, Rômulo Ribeiro Magalhães Post-Graduate Materials Science and Engineering Program Federal University of Piauí PI Teresina Brazil Post-Graduate Program in Materials Science Federal University of São Carlos São Carlos Brazil Post-Graduate Program in Chemistry Federal University of Piauí PI Teresina Brazil School of Science and Technology Federal University of Rio Grande do Norte RN Natal Brazil Brazil Department of Mechanical Engineering Federal University of Piauí PI Teresina Brazil Brazil

The industrial landscape has witnessed a growing demand for components exhibiting superior performance and extended lifespan, especially in parts made of stainless steels like AISI 409 steel, widely used in automotive exhaust systems, heat exchangers, and lightweight structural components. This study investigates the enhancement of surface properties of AISI 409 stainless steel through cathodic cage plasma nitriding (CCPN) and cathodic cage plasma deposition (CCPD) processes, focusing on the novel implementation of duplex treatments. The research aims to improve the mechanical strength, wear resistance, and corrosion resistance of the steel by forming nitrides and vanadium nitride films on its surface. The duplex treatments, specifically N400D450 and N450D450, were found to significantly enhance the hardness of AISI 409 stainless steel, with the N450D450 sample achieving a maximum hardness of 1100 HV—a 461.22% increase compared to the untreated steel. This enhancement is attributed to the formation of a thick, uniform nitrided layer followed by a vanadium nitride film. The critical role of processing order was highlighted, with the sequence of nitriding followed by deposition proving more effective than the reverse. Corrosion resistance was markedly improved in the duplex-treated samples. The N450D450 sample exhibited an Ecorr of -198 mV and reduced jcorr values, indicating superior resistance to corrosive environments. These results underscore the synergistic effect of combining nitriding and vanadium deposition, which optimizes the formation of protective surface layers. Overall, this study demonstrates that duplex treatments significantly enhance the surface properties of AISI 409 stainless steel, offering the potential for extended component lifespan and reduced maintenance in industrial applications. The findings suggest that careful control of process parameters and treatment sequence is essential for achieving optimal results. © 2024, The Authors. All rights

关键词： Tribology

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Plasmonic Nanolaser by Silver Nanowire Embedded in CsPbBr3 Quantum Dots

Plasmonic Nanolaser by Silver Nanowire Embedded in CsPbBr3 Q...

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JSAP-OSA Joint Symposia, JSAP 2021

作者： Xing, Di Lin, Cheng-Chieh Won, Phillip Xiang, Rong Chen, Tzu-Pei A. Kamal, A. Syazwan Lee, Yang-Chun Ho, Ya-Lun Maruyama, Shigeo Ko, Seung Hwan Chen, Chun-Wei Delaunay, Jean-Jacques School of Engineering The University of Tokyo Japan International Graduate Program of Molecular Science and Technology National Taiwan University Taiwan Department of Materials Science and Engineering National Taiwan University Taiwan Department of Mechanical Engineering Seoul National University Korea Republic of Center of Atomic Initiative for New Materials National Taiwan University Taiwan

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A problem-based learning case study for teaching voice over internet protocol - VoIP: Using asterisk as a tool for teaching VoIP for information technology classes

A problem-based learning case study for teaching voice over ...

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6th International Conference on Computer Supported Education, CSEDU 2014

作者： Dias, M.C. Gabi, C.F. Rodrigues, E.P. Souza, V.R. Perkusich, A. Coordination of Electrical Engineering Federal Institute of Education Science and Technology of Paraíba - IFPB João Pessoa Brazil Post-Graduate Program in Electrical Engineering - PpgEE - COPELE Electrical Engineering Department Federal University of Campina Grande - UFCG Campina Grande Brazil

ISBN: (纸本)9789897580215

This paper shows the use of PBL (Problem-Based Learning) technique as a key to learning VoIP in courses like Electrical engineering and Computer Networks in conjunction with open source and the public domain software called Asterisk which was used to create the scenario of the experiment and the problems presented to the students. In order to make the validation, the experiment was applied to students of Bachelor in Electrical engineering and in Communication Technology System, undergraduate courses at the Federal Institute of Education, science and Technology of Paraíba - IFPB, in the Telephony subject, with promising results. The Asterisk software was presented as a useful and flexible tool for constructing scenarios and problems for the teaching of VoIP technologies and the used approach resulted as effective for improving the attainment of the defined learning objectives.

关键词： Teaching

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Effects of nanopores and sulfur doping on hierarchically bunched carbon fibers to protect lithium metal anode

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Carbon Energy 2021年第5期3卷 784-794页

作者： Ji In Jung Sunwoo Park Son Ha Se Youn Cho Hyoung-Joon Jin Young Soo Yun Program in Environmental and Polymer Engineering Inha UniversityIncheonSouth Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoulSouth Korea Carbon Composite Materials Research Center Korea Institute of Science and TechnologyWanju-gunJeollabuk-doSouth Korea Department of Polymer Science and Engineering Inha UniversityIncheonSouth Korea Department of Integrative Energy Engineering Korea UniversitySeoulSouth Korea

Studies on three-dimensional structured carbon templates have focused on how to guide homogeneous lithium metal nucleation and growth for lithium metal anodes(LMAs).However,there is still insufficient evidence for a key factor to achieve their high electrochemical ***,the effects of nanopores and sulfur doping on carbon-based nanoporous host(CNH)electrode materials for LMAs were investigated using natural polymer-derived *** pore-filling behaviors of lithium metal in the nanopores of the CNH electrode materials were first observed by ex situ scanning electron microscopy analysis,where the protective lithium metal nucleation and growth process led to significantly high Coulombic efficiency(CE)of~99.4%and stable 600 *** addition,a comparison study of CNH and sulfurdoped CNH(S-CNH)electrodes,which differ only in the presence or absence of sulfur,revealed that sulfur doping can cause lower electrochemical series resistance,higher CE value,and better cycling stability in a wide range of current densities and number of ***,S-CNH-based LMAs showed high electrochemical performance in full-cell Li-S battery tests using a sulfur copolymer cathode,where a high energy density of 1370Wh kgelectrode−1 and an excellent power density of 4120Wkgelectrode−1 were obtained.

关键词： carbon template Li-S batteries lithium metal anode lithium metal batteries nanoporous carbon sulfur doping

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Characterizations of trimetallic heteronuclear Bi1-xLa x[Fe(CN)6]·n(H2O) complexes and their thermal decomposition products

Characterizations of trimetallic heteronuclear Bi1-xLa x[Fe(...

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作者： Aono, Hiromichi Kondo, Nobuyuki Katagishi, Haruo Kurihara, Masato Sakamoto, Masatomi Sadaoka, Yoshihiko Department of Materials Science and Engineering Faculty of Engineering Ehime University Matsuyama 790-8577 Japan Graduate Program of Human Sensing and Functional Sensor Engineering Graduate School of Science and Engineering Yamagata University Yamagata 990-8560 Japan Department of Material and Biological Chemistry Faculty of Science Yamagata University Yamagata 990-8560 Japan

Heteronuclear Bi1-x La x [Fe(CN)6] &middotnH2O complexes were synthesized, and their crystal structures and thermal decomposition process were investigated by X-ray diffraction (XRD), thermogravimetry analysis (TG... 详细信息

Heteronuclear Bi1-x La x [Fe(CN)6] ·nH2O complexes were synthesized, and their crystal structures and thermal decomposition process were investigated by X-ray diffraction (XRD), thermogravimetry analysis (TGA), Auger electron spectroscopy (AES) with scanning electron microscope (SEM), and transmission electron microscopy (TEM). The crystal system of the complexes was orthorhombic having n = 4 for x = 0-0.7 and was hexagonal having n = 5 for x = 1.0. Their mixture was confirmed for x = 0.8 and 0.9. The lattice parameters for the orthorhombic increased with increasing the x value for the complexes. The single phase of trimetallic perovskite-type Bi1-x La x FeO3 was obtained by its thermal decomposition at low temperature. The crystal system was hexagonal for BiFeO3 (x = 0) and orthorhombic for x = 0.1-1.0. In the case of the decomposed perovskite sample, the lattice parameters decreased with increasing x values for Bi1-x La x FeO3. The particle size was ca. 30 nm for Bi0.2La0.8FeO3 obtained by thermal decomposition at 500 °C and it grew with an increase in decomposition temperature. For the Bi0.5La0.5FeO 3, AES showed that the elemental distributions of Bi, La, and Fe on the surface were very homogeneous for the sample decomposed at 700 °C.

关键词： Bismuth compounds

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