• Electrical & Electronic Materials
• /
• v.5 no.4
• /
• pp.393-399
• /
• 1992

In order to increase the coupling strength between bisphenol-A type epoxy resin and filler SiO$_{2}$ it was treated to filler with silane coupling agent[KBM-603]. To observe how silane coupling agent effects on dielectric breakdown strength of Epoxy/SiO$_{2}$ compound material, specimens of eight type were made like following. (A-1, A-2), (B-1, B-2), (C-1, C-2), (D-1, D-2) (see 2-2. Specimen) Specimen treated with silane coupling agent had always bigger dielectric breakdown strength than non-treated specimen. Under the influence of silane coupling agent, increment ratio of dielectric breakdown strength at specimen manufactured by hand drill was very bigger than that of specimen inserted spherical electrode. Therefore, as the specimen shape was varied, it was studied on effect that silane coupling agent affects on dielectric breakdown strength of Epoxy/SiO$_{2}$ compound material.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.5
• /
• pp.963-968
• /
• 2008

For the [$Cr_2(H_2tmp)_2Cl_4$] compound, simplified models with two bridging methoxo ligands have been studied. The influence of the bridging Cr-O-Cr bond angles on the exchange coupling between metal atoms in the model compound has been analyzed by means of density functional calculations with the broken-symmetry approach. Coupling constant calculated for the full structure is in good agreement with the experimentally reported value, confirming the validity of the computational strategy used in this work to predict the exchange coupling in a family of related dinuclear Cr(III) compounds. The calculations indicate a good correlation between the calculated coupling constant and the sum of the squared energy gap of three pairs of metal $t_{2g}$ OMSOs with a limited variation of the Cr-O-Cr angle. The spin density distribution and the mechanism of magnetic coupling interactions are discussed.

• Asia pacific journal of information systems
• /
• v.28 no.1
• /
• pp.19-35
• /
• 2018

This study uses the concepts of mental accounting and coupling in consumption to demonstrate a systematic relationship between behavioral costs, sunk costs, coupling, and user intention to discontinue social network services (SNS) use. An analysis of 213 SNS users found that coupling and sunk costs are two major factors that influence an individual's intention to discontinue SNS use. An interesting finding of this study is that the perception of coupling is created by behavioral costs in the context of an SNS. This finding implies that the source of cost perception when perceiving coupling may differ depending on whether the product or service is traditional or web-based. These results contribute to an expansion of the theoretical discussion of individual-level discontinuance intention after adopting SNS by conceptualizing the perception of coupling.

• Current Optics and Photonics
• /
• v.5 no.5
• /
• pp.538-543
• /
• 2021

The evanescent wave coupling of a microring resonator is controlled by changing the gap distance between the bus waveguide and the microring waveguide. However, the interdependence of the bus waveguide's width and the coupling is not well understood. In this paper, we investigate the dependence of coupling strength on the bus waveguide's width. The strength of the evanescent wave coupling is analytically calculated using coupled-mode theory (CMT) and numerically calculated by three-dimensional finite-difference-time-domain (FDTD) simulation. The analytic and numerical simulation results show that the phase-matching condition in evanescent wave coupling does not provide maximum coupling strength, because both phase-matching and mode confinement influence the coupling. The analytic and simulation results for the evanescent coupling correspond to the experimental results. The optimized bus-waveguide width that provides maximum coupling strength results in intrinsic quality factors of up to 1.3 × 10⁶. This study provides reliable guidance for the design of microring resonators, depending on various applications.

• Wind and Structures
• /
• v.29 no.6
• /
• pp.431-440
• /
• 2019

The aim of this study was to explore the influence of structure coupling effect on structural damping of blade based on the blade vibration characteristic. For this purpose, the scaled blade model of NREL 5 MW offshore wind turbine was processed and employed in the wind tunnel test to validate the reliability of theoretical and numerical models. The attenuation curves of maximum displacement and the varying curves of equivalent damping coefficient of the blade under the rated condition were respectively compared and analyzed by constructing single blade model and whole machine model. The attenuation law of blade dynamic response was obtained and the structure coupling effect was proved to exert a significant influence on the equivalent damping coefficient. The results indicate that the attenuation trend of the maximum displacement response curve of the single blade varies more obviously with the increase of elastic modulus as compared to that under the structure coupling effect. In contrast to the single blade model, the varying curve of equivalent damping coefficient with the period is relatively steep for the whole machine model. The findings are of great significance to guide the structure design and material selection for wind turbine blades.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.5
• /
• pp.427-432
• /
• 1995

A model based on two coupled generalized Langevin equations is proposed to investigate the trans-stilbene photoisomerization dynamics. In this model, a system which has two independent coordinates is considered and these two system coordinates are coupled to the same harmonic bath. The direct coupling between the system coordinates is assumed negligible and these two coordinates influence each other through the frictional coupling mediated by solvent molecules. From the Hamiltonian which is equivalent to the coupled generalized Langevin equations, we obtain the transition state theory rate constants of the stilbene photoisomerization. The rates obtained from this model are compared to experimental results in n-alkane solvents.

• Wind and Structures
• /
• v.10 no.4
• /
• pp.383-398
• /
• 2007

The paper describes a study of the effects of structural coupling on the wind-induced response of twin tall buildings connected by a skybridge. Development of a dual high-frequency force balance used in wind tunnel investigation and background information on the methodology employed in analysis are presented. Comparisons of the wind-induced building response (rooftop acceleration) of structurally coupled and uncoupled twin buildings are provided and the influence of structural coupling is assessed. It is found that the adverse aerodynamic interference effects caused by close proximity of the buildings can be significantly reduced by the coupling. Neglecting of such interactions may lead to excessively conservative estimates of the wind-induced response of the buildings. The presented findings suggest that structural coupling should be included in wind-resistant design of twin tall buildings.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.9
• /
• pp.2245-2250
• /
• 1994

The normal coordinates of a nonclassically damped systems are coupled by nonzero off-diagonal elements of modal damping matrix. The relationship between modal coupling and the frequency separation of the natural modes is presented in this paper. Contrary to widely accepted beliefs, increasing the frequency separation of the natural modes does not neccessarily diminish the effect of modal coupling. Consequently, in the pratical engineering applications, wide frequency separation of the natural modes would not be sufficient for neglecting modal coupling.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.206-209
• /
• 2002

The purpose of this research was to find influence of compounding materials on electrical properties of silicone rubber such as tracking characteristic. The tracking characteristic was tested through controlling the ATH, a widely use anti-tracking agent. Regarding the particle size and coupling agent of ATH, compound silicone rubber with ATH of coupling agent and larger diameter showed better anti-tracking properties. It can be included that ATH of coupling agent use vinyl silane, dispose of tracking characteristic was achieve excellant results.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.7
• /
• pp.2341-2344
• /
• 2012

A molecular orbital study is presented of the magnetic coupling in the one-dimensional vanadium oxide $Ba_2V_3O_9$ with a bridge formed by two different types of $VO_4$ tetrahedra. The concept of complementary versus counter-complementary effect has been used to explain the structural origin of the magnetic behavior of the compound. Namely, the observed antiferromagnetic coupling is dominated by the orbital complementarity of the V(1) tetrahedra sharing only one oxygen corner with two adjacent $VO_6$ octahedra. The second type of V(2) tetrahedra does not provide a noticeable contribution to the magnetic coupling due to the orbital counter-complementarity of the bridging ligand.