检索结果-内蒙古大学图书馆

Controlled synthesis, characterization and reduction of graphene oxide: A convenient method for large scale production

引用

Egyptian Journal of Basic and Applied sciences 2017年第1期4卷 74-79页

作者： Tarko Fentaw Emiru Delele Worku Ayele Material Science and Engineering Program College of Science Bahir Dar University P.O. Box 79 Bahir Dar Ethiopia Department of Chemistry College of Science Bahir Dar University P.O. Box 79 Bahir Dar Ethiopia Energy Research Center Bahir Dar Institute of Technology Bahir Dar University P.O. Box 79 Bahir Dar Ethiopia

In this work, graphene oxide was synthesized by treating graphite powder with KMnO 4 and a mixture of concentrated H 2 SO 4 /H 3 PO 4 and reduced with ascorbic acid to produce reduced graphene oxide. The effects of reaction parameters such as reaction time, reaction temperature and amount of KMnO 4 on the degree of oxidation of graphite powder to graphene oxide were studied. The prepared graphene oxide and reduced graphene oxide were characterized by UV–Visible spectroscopy, FT-IR spectroscopy, and XRD. The results showed that treating graphite powder with KMnO 4 at 40 °C for 12 h resulted in better degree of oxidation. The designed synthesis strategy could be simple/convenient, easily controlled and an alternative approach for large scale production of graphene oxide (GO) and reduced graphene oxide (rGO).

关键词： Graphite powder Graphene oxide Reduced graphene oxide Optical properties Large scale production

来源：评论

学校读者我要写书评

暂无评论

Long-term Room Temperature Instability in Thermal Conductivity of InGaZnO Thin Films

Long-term Room Temperature Instability in Thermal Conductivi...

引用

作者： Cui, Boya Bruce Buchholz, D. Zeng, Li Bedzyk, Michael Chang, Robert P. H. Grayson, Matthew Applied Physics Program Northwestern University EvanstonIL60208 United States Electrical Engineering and Computer Science Northwestern University EvanstonIL60208 United States Material Science and Engineering Northwestern University EvanstonIL60208 United States

The cross-plane thermal conductivities of InGaZnO (IGZO) thin films in different morphologies were measured on three occasions within 19 months, using the 3ω method at room temperature 300 K. Amorphous (a-), semi-crystalline (semi-c-) and crystalline (c-) IGZO films were grown by pulsed laser deposition (PLD), followed by X-ray diffraction (XRD) for evaluation of film quality and crystallinity. Semi-c-IGZO shows the highest thermal conductivity, even higher than the most ordered crystal-like phase. After being stored in dry low-oxygen environment for months, a drastic decrease of semi-c-IGZO thermal conductivity was observed, while the thermal conductivity slightly reduced in c-IGZO and remained unchanged in a-IGZO. This change in thermal conductivity with storage time can be attributed to film structural relaxation and vacancy diffusion to grain boundaries. © 2016 materials Research Society.

关键词： Thin films

来源：评论

学校读者我要写书评

暂无评论

Lateral load performance evaluation of larch glulam portal frames using GFRP-reinforced laminated plate and GFRP rod

Journal of the Korean Wood Science and Technology

引用

Journal of the Korean Wood science and Technology 2016年第1期44卷 30-39页

作者： Jung, Hong-Ju Song, Yo-Jin Lee, In-Hwan Hong, Soon-Il Program of Forest Biomaterials Engineering Division of Forest Material Science and Engineering Kangwon National University Chuncheon24341 Korea Republic of

The evaluation of the lateral load performance for larch glulam portal frames was carried out using glass fiber reinforced plastic (GFRP) as connector in two different systems: the GFRP-reinforced laminated plates combined with veneer, and GFRP rod joints glued with epoxy resins to replace usual metal connectors for the structural glulam rahmen joints. As a result the yield strength, ultimate strength, initial stiffness of glulams of GFRP rod joints glued with epoxy resin decreased to 49%, 52% and 61% compared to those of the conventional metal connector. This connector will be a stress device where the bonding strength between the GFRP rod and glued laminated timber is important. Thus, there will be a high possibility that a problem may occur when it is applied to the field. On the other hand, the GFRP reinforced laminated plates and wood (Eucalyptus marginata) pin were measured all within 3% for all measurements of the yield strength, ultimate strength, initial strength and ductility factor, regardless of high cross sectional loss on the glued laminated timber slit joint. In addition, the variation of stiffness on the cycle was 35%, which was the lowest, confirming that it was almost the same performance as the specimen prepared with the metal connector.

关键词： Timber

来源：评论

学校读者我要写书评

暂无评论

Moment resistance performance evaluation of larch glulam joints using GFRP-reinforced laminated plate and GFRP rod

Journal of the Korean Wood Science and Technology

引用

Journal of the Korean Wood science and Technology 2016年第1期44卷 40-47页

Instead of metal connector generally used on the structural glued laminated timber rahmen joints, the GFRP reinforced laminated plates combining veneer and GFRP (Glass Fiber Reinforced Plastic) and bonded type GFRP rod were used as the connectors. As a result of moment resistance performance evaluation on the joint part applied with these connectors, the yield moment of specimen using the GFRP reinforced laminated plates and GFRP rod pin was measured 4 % lower in comparison to the specimen (Type-1) using the metal connectors, but the initial rotational stiffness was measured 29% higher. Also, the yield moment and rotational stiffness of the specimen using the GFRP-reinforced laminated plates and wood (Eucalyptus marginata) pin showed were measured 11% and 56% higher in comparison to the Type-1 specimen, showing the best performance. It was also confirmed through the failure shape and perfect elasto-plasticity analysis that it showed ductility behavior, not brittle fracture, from the shear resisting force by the pin and the bonding strength increased and the unification of member was carried out. On the other hand, in case of the specimen bonded with GFRP rod, it was impossible to measure the bonding performance or it was measured very low due to poor bonding.

关键词： Plates (structural components)

来源：评论

学校读者我要写书评

暂无评论

Definition of periodic boundary conditions in explicit dynamic simulations of micro- or meso-scale unit cells with conformal and non-conformal meshes 17

Definition of periodic boundary conditions in explicit dynam...

引用

17th European Conference on Composite materials, ECCM 2016

作者： Garoz, D. Gilabert, F.A. Sevenois, R.D.B. Spronk, S.W.F. Rezaei, A. Van Paepegem, W. Department of Material Science and Engineering Faculty of Engineering and Architecture Ghent University Tech Lane Ghent Science Park - Campus A Technologiepark Zwijnaarde 903 ZwijnaardeB-9052 Belgium SIM Program M3Strength Technologiepark Zwijnaarde 935 ZwijnaardeB-9052 Belgium

ISBN: (纸本)9783000533877

Although Periodic Boundary Conditions (PBCs) have been extensively used in finite elements to analyze unit cell models of composites, there are few reported investigations using explicit dynamic simulations. While different formulations and implementations of PBCs do not affect the results of quasi-static simulations solved by an implicit solver, they have an impact on the results of dynamic simulations solved by an explicit solver. A simple benchmark with a cubic unit cell of an isotropic linear elastic material is used to compare the results of different scenarios, which have different formulations and implementation of PBCs. The stress-strain curves under simple uniaxial tension shows that, in some scenarios, the explicit analyses do not follow the expected linear elastic behavior. These unexpected results are remarkable when the characteristic length of the model is in the range of few microns. This work encapsulates the relevant features of the different formulations and implementations of PBCs, and indicates in which scenarios the PBCs must be carefully applied. © 2016, European Conference on Composite materials, ECCM. All rights reserved.

关键词： Stress-strain curves

来源：评论

学校读者我要写书评

暂无评论

Liquid crystal self-assembly of upconversion nanorods enriched by depletion forces for mesostructured material preparation

arXiv

引用

arXiv 2017年

作者： Xie, Yong Li, Yuanyuan Wei, Guoqing Liu, Qingkun Mundoor, Haridas Chen, Ziyu Smalyukh, Ivan I. Department of Physics Material Science and Engineering Program Department of Electrical Computer& Energy Engineering Liquid Crystal Materials Research Center University of Colorado BoulderCO80309 United States Department of Physics Beihang University Beijing100191 China National Renewable Energy Laboratory and University of Colorado Renewable and Sustainable Energy Institute BoulderCO80309 United States

Monodisperse rod-like colloidal particles are known for spontaneously forming both nematic and smectic liquid crystal phases, but their self-assembly was typically exploited from the fundamental soft condensed matter physics perspective. Here we demonstrate that depletion interactions, driven by non-adsorbing polymers like dextran and surfactants, can be used to enrich self-organization of photon-upconversion nanorods into orientationally ordered nematic and smectic-like membrane colloidal superstructures. We study thermodynamic phase diagrams and demonstrate polarization-dependent photon upconversion exhibited by the ensuing composites, which arises from the superposition of unique properties of the solid nanostructures and the long-range ordering enabled by liquid crystalline self-organization. Finally, we discuss how our method of utilizing self-assembly due to the steric and electrostatic interactions, along with attractive depletion forces, can enable technological uses of lyotropic colloidal liquid crystals and mesostructured composite materials enabled by them, even when they are formed by anisotropic nanoparticles with relatively small aspect ratios. Copyright © 2017, The Authors. All rights reserved.

关键词： Nanorods

来源：评论

学校读者我要写书评

暂无评论

Micro-scale finite element study of the damping in unidirectional fiber reinforced composites 17

Micro-scale finite element study of the damping in unidirect...

引用

17th European Conference on Composite materials, ECCM 2016

作者： Rezaei, A. Garoz, D. Faes, J. Gilabert, F.A. Desmet, W. Van Paepegem, W. Department of Material Science and Engineering Faculty of Engineering and Architecture Ghent University Tech. Lane Ghent Science Park - Campus A Technologiepark 903 Zwijnaarde Belgium Section Department of Mechanical Engineering KULeuven Leuven Belgium SIM Program M3Strength Technologiepark Zwijnaarde 935 ZwijnaardeB-9052 Belgium

ISBN: (纸本)9783000533877

This article employs the strain energy finite element method to study the anisotropic damping of unidirectional fiber reinforced composites in micro-scale. The simulations have been performed on a Representative Volume Element composed of randomly distributed glass fibers in an epoxy polymer matrix. The models include also Periodic Boundary Conditions. Influence of the fiber volume fraction on the loss factors of a unidirectional fiber reinforced composite is investigated. At the end of the article, using a simplified model, effect of a homogeneous and isotropic hard or soft interphases on the loss factors of a composite is studied. © 2016, European Conference on Composite materials, ECCM. All rights reserved.

关键词： Damping

来源：评论

学校读者我要写书评

暂无评论

Light-emitting hyperbolic metasurfaces at telecom frequencies

Light-emitting hyperbolic metasurfaces at telecom frequencie...

引用

Novel Optical materials and Applications, NOMA 2016

作者： Smalley, Joseph S.T. Vallini, Felipe Montoya, Sergio Ferrari, Lorenzo Riley, Conor T. Shahin, Shiva Kanté, Boubacar Fullerton, Eric Liu, Zhaowei Fainman, Yeshaiahu Department of Electrical and Computer Engineering University of California San Diego United States Material Science Program University of California San Diego United States Department of NanoEngineering University of California San Diego United States

We demonstrate light-emitting hyperbolic metasurfaces in the 1200-1600nm spectral range. The multilayer configuration, ideal for planar integration, enables characterization of hyperbolic dispersion by polarization an... 详细信息

ISBN: (纸本)9781943580149

关键词： Light

来源：评论

学校读者我要写书评

暂无评论

Magnetoresistance in the superconducting state at the (111) LaAlO3/SrTiO3 interface

引用

Physical Review B 2017年第13期96卷 134502-134502页

作者： S. Davis Z. Huang K. Han Ariando T. Venkatesan V. Chandrasekhar Graduate Program in Applied Physics Northwestern University 2145 Sheridan Road Evanston Illinois 60208 USA NUSNNI-Nanocore National University of Singapore 117411 Singapore Department of Physics National University of Singapore 117551 Singapore NUS Graduate School for Integrative Sciences & Engineering National University of Singapore 117456 Singapore Department of Electrical and Computer Engineering National University of Singapore 117576 Singapore Department of Material Science and Engineering National University of Singapore 117575 Singapore Department of Physics and Astronomy Graduate Program in Applied Physics Northwestern University 2145 Sheridan Road Evanston Illinois 60208 USA

Condensed-matter systems that simultaneously exhibit superconductivity and ferromagnetism are rare due the antagonistic relationship between conventional spin-singlet superconductivity and ferromagnetic order. In materials in which superconductivity and magnetic order are known to coexist (such as some heavy-fermion materials), the superconductivity is thought to be of an unconventional nature. Recently, the conducting gas that lives at the interface between the perovskite band insulators LaAlO3 (LAO) and SrTiO3 (STO) has also been shown to host both superconductivity and magnetism. Most previous research has focused on LAO/STO samples in which the interface is on the (001) crystal plane. Relatively little work has focused on the (111) crystal orientation, which has hexagonal symmetry at the interface, and has been predicted to have potentially interesting topological properties, including unconventional superconducting pairing states. Here we report measurements of the magnetoresistance of (111) LAO/STO heterostructures at temperatures at which they are also superconducting. As with the (001) structures, the magnetoresistance is hysteretic, indicating the coexistence of magnetism and superconductivity, but in addition, we find that this magnetoresistance is anisotropic. Such an anisotropic response is completely unexpected in the superconducting state and suggests that (111) LAO/STO heterostructures may support unconventional superconductivity.

关键词： Coherence length Ferromagnetism Magnetotransport Phase diagrams Superconducting phase transition Superconductivity Hall bar Resistivity measurements

来源：评论

学校读者我要写书评

暂无评论

CuFeO2 formation using fused deposition modeling 3D printing and sintering technique

引用

Journal of Physics: Conference Series 2017年第1期901卷

作者： A Salea A Dasaesamoh R Prathumwan T Kongkaew K Subannajui Advanced Material Processing Laboratory Material science and engineering program Faculty of science Mahidol University Bangkok 10400 Thailand Faculty of Science technology and Agricultural Yala Rajabhat University Yala 95000 Thailand

CuFeO2 is a metal oxide mineral material which is called delafossite. It can potentially be used as a chemical catalyst, and gas sensing material. There are methods to fabricate CuFeO2 such as chemical synthesis, sintering, sputtering, and chemical vapor deposition. In our work, CuFeO2 is prepared by Fused Deposition Modeling (FDM) 3D printing. The composite filament which composed of Cu and Fe elements is printed in three dimensions, and then sintered and annealed at high temperature to obtain CuFeO2. Suitable polymer blend and maximum percent volume of metal powder are studied. When percent volume of metal powder is increased, melt flow rate of polymer blend is also increased. The most suitable printing condition is reported and the properties of CuFeO2 are observed by Scanning Electron Microscopy, and Dynamic Scanning Calorimeter, X-ray diffraction. As a new method to produce semiconductor, this technique has a potential to allow any scientist or students to design and print a catalyst or sensing material by the most conventional 3D printing machine which is commonly used around the world.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：