• Steel and Composite Structures
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• v.31 no.6
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• pp.591-600
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• 2019

Based on the energy-variational principle, a coupling vibration analysis model of high-speed railway simply supported beam bridge-track structure system (HSRBTS) was established by considering the effect of shear deformation. The vibration differential equation and natural boundary conditions of HSRBTS were derived by considering the interlayer slip effect. Then, an analytic calculation method for the natural vibration frequency of this system was obtained. By taking two simply supported beam bridges of high-speed railway of 24 m and 32 m in span as examples, ANSYS and MIDAS finite-element numerical calculation methods were compared with the analytic method established in this paper. The calculation results show that two of them agree well with each other, validating the analytic method reported in this paper. The analytic method established in this study was used to evaluate the natural vibration characteristics of HSRBTS under different interlayer stiffness and length of rails at different subgrade sections. The results show that the vertical interlayer compressive stiffness had a great influence on the high-order natural vibration frequency of HSRBTS, and the effect of longitudinal interlayer slip stiffness on the natural vibration frequency of HSRBTS could be ignored. Under different vertical interlayer stiffness conditions, the subgrade section of HSRBTS has a critical rail length, and the critical length of rail at subgrade section decreases with the increase in vertical interlayer compressive stiffness.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1410-1411
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• 2011

Tip-type carbon nanotube(CNT) based electron emitters were fabricated by forming a hafnium(Hf) interlayer between the CNT and the substrate. The CNTs were deposited by using the electrophoretic deposition method and thermally treated. No significant change in the microscopic structure of the CNTs, such as the ratio of length to diameter, was observed after the deposition of Hf interlayer and thermal treatment. As compared with the CNT emitter without the Hf-interlayer and thermal treatment, the CNT emitter with the Hf-interlayer and thermal treatment showed noticeably improved electron-emission properties due to the enhanced adhesion.

• Steel and Composite Structures
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• v.46 no.1
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• pp.93-105
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• 2023

This paper examines a high-speed railway CRTS-II ballastless track-bridge system. Using the stationary potential energy theory, the mapping analytical solution between the bridge deformation and the rail vertical geometric irregularity was derived. A theoretical model (TM) considering the nonlinear stiffness of interlayer components was also proposed. By comparing with finite element model results and the measured field data, the accuracy of the TM was verified. Based on the TM, the effect of bridge deformation amplitude, girder end cantilever length, and interlayer nonlinear stiffness (fastener, cement asphalt mortar layer (CA mortar layer), extruded sheet, etc.) on the rail vertical geometric irregularity were analyzed. Results show that the rail vertical deformation extremum increases with increasing bridge deformation amplitude. The girder end cantilever length has a certain influence on the rail vertical geometric irregularity. The fastener and CA mortar layer have basically the same influence on the rail deformation amplitude. The extruded sheet and shear groove influence the rail geometric irregularity significantly, and the influence is basically the same. The influence of the shear rebar and lateral block on the rail vertical geometric irregularity could be negligible.

• Journal of the Korean Applied Science and Technology
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• v.23 no.4
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• pp.290-299
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• 2006

This article investigated to polymer-clay nanocomposite, especially in interfacial respect clay structure, its dispersion into polymer matrix, and clay modification is studied. The cationic exchange of surfactants with clay gallery results in preparing organo-clay capable of compatiblizing to monomer or polymer and increasing interlayer adhesion energy due to expansion of interlayer spacing. The orientation of surfactant in clay gallery is affected by chemical structure and charge density of clay, and interlayer spacing and volume is increased with alkyl chain length of surfactant, or charge density of clay. Also, the interaction between clay and polymer in preparing polymer-clay nanocomposite is explained thermodynamically. In the future, the study and development of polymer-clay nanocomposite is paid attention to the interfacial adhesion, clay dispersion within polymer, mechanism of clay intercalation or exfoliation.

• Polymer(Korea)
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• v.24 no.6
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• pp.794-801
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• 2000

The effect of chain length and packing density of intercalated surfactants, annealing temperature, and annealing time on static melt intercalation of thermoplastic polymers was examined using x-ray and FTIR spectroscopy. Although melt intercalation of polymers was not successful when alkyl chains in organosilicates form a lateral monolayer structure, the type and structure of surfactants could not much affect final interlayer distances of most polymer/silicate hybrids. As annealing time increases, interlayer distance in organosilicates increases while the dispersity of the spacing between silicate layers decreases. However, the dispersity of interlayer spacing as well as interlayer distance in organosilicates increase with annealing temperature.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.2
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• pp.63-67
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• 2015

$TiO_2/Ag/TiO_2$ trilayer films were deposited with radio frequency (RF) and direct current (DC) magnetron sputtering onto the glass substrate to consider the influence of Ag interlayer on the optical properties of the films. The thickness of $TiO_2$ films was kept at 24 nm, while the thickness of Ag interlayer was varied as 5, 10, 15, and 20 nm. As-deposited $TiO_2$ single layer films show the optical transmittance of 66.7% in the visible wave-length region and the optical reflectance of 16.5%, while the $TiO_2$ films with a 15 nm thick Ag interlayer show the enhanced optical transmittance of 80.2% and optical reflectance of 77.8%. The carrier concentration was also influenced by Ag interlayer. The highest carrier concentration of $1.01{\times}10^{23}cm^{-3}$ was observed for a 15 nm thick Ag interlayer in $TiO_2/Ag/TiO_2$ films. The observed result means that an optimized Ag interlayer in $TiO_2/Ag/TiO_2$ films enhanced the structural and optical properties of the films.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.338-347
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• 2021

This paper aims to evaluating the interlayer strength of 3D-printed concrete with interlayer reinforcement. According to lap splices, two reinforcement methods were considered. One method did not include lap splices of interlayer reinforcement, but the other method included lap splices with length of 40mm. In addition, two different curing conditions were applied: air curing conditions and water curing conditions. The compressive, splitting tensile, and flexural tensile strengths of 3D-printed concrete specimens were measured in three loading directions with different reinforcement methods and curing conditions. Splitting and flexural tensile strengths decreased considerably when tensile stresses acted over the interlayers of 3D-printed concrete specimens. However, the flexural tensile strength or interlayer bonding strength of the printed specimens increased significantly at the interlayers when the longitudinal interlayer reinforcement penetrated printed layers. Interlayer bonding strength of printed concrete decreased after air curing treatment was applied because interlayers of printed concrete with more pores formed by the air cu ring conditions are more vulnerable to the load.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.1
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• pp.27-34
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• 2017

In this study, desorption characteristics of Cs from clay according to the hydrophobic alkyl chain length of the cationic surfactant were investigated. Alkyltrimethylammonium bromide was used as a cationic surfactant, and the length of the hydrophobic alkyl chain of the cationic surfactant was varied from -octyl to -cetyl. The adsorbed amount of the cationic surfactant on montmorillonite increased with the length of the hydrophobic alkyl chain, and intercalation of the cationic surfactant into the clay interlayer increased the interlayer distances. The Cs removal efficiency was also enhanced with increasing alkyl chain length, and the cationic surfactant with the cetyl group showed a maximum Cs removal efficiency of $992{\pm}2.9%$.

• Korean Journal of Materials Research
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• v.13 no.11
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• pp.711-716
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• 2003

Gate length, height, and silicide thickness have all been shrinking linearly as device density has progressively increased over the years. We investigated the effect of the cobalt diffusion during the silicide formation process on the 60$\AA$-thick gate oxide lying underneath the Ti/Co and Co/Ti bilayers. We prepared four different cobalt silicides, which have similar sheet resistance, made from the film structure of Co/Ti(interlayer), and Ti(capping layer)/Co, and peformed the current-voltage, time-to-break down, and capacitance-voltage measurements. Our result revealed that the cobalt silicide process without the Ti capping layer allowed cobalt atoms to diffuse into the upper interface of gate oxides. We propose that 100$\AA$-thick titanium interlayer may lessen the diffusion of cobalt to gate oxides in 1500-$\AA$ height polysilicon gates.

• Journal of Welding and Joining
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• v.15 no.2
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• pp.43-53
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• 1997

The complete joining method for dissimilar press punch materials and its real-time evaluation method is not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction welding with a diffusion mechanism in bonding was applied in this study. This work was carried out to determine the proper friction welding conditions and to analyze mechanical properties of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch) using aluminum (A6061 for the interlayer material) as an insert material between the sintered carbide tool materials and the alloy steel. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.