• Geomechanics and Engineering
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• 제12권6호
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• pp.1021-1046
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• 2017

The assessment of slope stability is an essential task in geotechnical engineering. In this paper, a three-dimensional (3D) finite element analysis (FEA) was employed to investigate the performance of different shear pin arrangements to increase the stability of a soil block resting on an inclined plane with a low-interface friction plane. In the numerical models, the soil block was modeled by volume elements with linear elastic perfectly plastic material in a drained condition, while the shear pins were modeled by volume elements with linear elastic material. Interface elements were used along the bedding plane (bedding interface element) and around the shear pins (shear pin interface element) to simulate the soil-structure interaction. Bedding interface elements were used to capture the shear sliding of the soil on the low-interface friction plane while shear pin interface elements were used to model the shear bonding of the soil around the pins. A failure analysis was performed by means of the gravity loading method. The results of the 3D FEA with the numerical models were compared to those with the physical models for all cases. The effects of the number of shear pins, the shear pin locations, the different shear pin arrangements, the thickness and the width of the soil block and the associated failure mechanisms were discussed.

• Journal of the Optical Society of Korea
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• 제20권3호
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• pp.427-430
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• 2016

The effect of the liquid density difference on interface shape of a double-liquid lens is analyzed in detail. The expressions of interface shape of two liquids with liquid density difference are analyzed and fitted with “even asphere”. The imaging analysis of the aspheric interface shape of a double-liquid lens is presented. The results show that the density difference of two liquids can cause the interface to be an aspheric surface, which can improve the image quality of a double-liquid lens. The result provides a new selection for the related further research and a wider application field for liquid lenses.

• 비파괴검사학회지
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• 제27권6호
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• pp.582-590
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• 2007

Imperfectly jointed interface serves as mechanical waveguide for elastic waves and gives rise to two distinct kinds of guided wave propagating along the interface. Contact acoustic nonlinearity (CAN) is known to plays major role in the generation of these interface waves called generalized Rayleigh waves in non-welded interface. Closed crack is modeled as non-welded interface that has nonlinear discontinuity condition in displacement across its boundary. Mathematical analysis of boundary conditions and wave equation is conducted to investigate the dispersive characteristics of the interface waves. Existence of the generalized Rayleigh wave(interface wave) in nonlinear contact interface is verified in theory where the dispersion equation for the interface wave is formulated and analyzed. It reveals that the interface waves have two distinct modes and that the phase velocity of anti-symmetric wave mode is highly dependent on contact conditions represented by linear and nonlinear dimensionless specific stiffness.

• Journal of Mechanical Science and Technology
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• 제15권2호
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• pp.172-179
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• 2001

The effects of the interface and two holes located near the crack path in the hybrid specimen on the dynamic crack propagation behavior have been investigated using dynamic photoelasticity with the aid of Cranz-Shardin type high speed camera system. The dynamic stress field around the dynamically propagating interface crack tip in the three point bending specimens under a dynamic load applied by a hammer dropped from 0.6m high without initial velocity are recorded. The complex stress intensity factors for the dynamically propagating interface crack are extracted by using a overdeterministic least square method. Theoretical dynamic interface isochromatic fringe loops generated by using the numerically determined complex stress intensity factors are compared with the experimental results. Furthermore, the influence of the hole to the dynamic interface crack velocities has been investigated experimentally.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.128-131
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• 1992

In this paper, the skewness properties of partial discharge at interface layer in mica-epoxy composite material were investigated and studied on interface specimens which has internal electrodes. As a result, it has been confirmed that the interface exists as abnormal resin layer and the contact condition at the interface is depended upon the density of si lane aqueous solution. The Pulse frequency of discharge at abnormal interface has been shown a linear increasing with enlargement of discharge quantity according to rising of the applied voltage. Whereas, in case of normal interface, pulse frequency represented exponential increasing at the saturating point of discharge quantity. The aging model can be represented from the variable characteristics of skewness.

• Structural Engineering and Mechanics
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• 제80권5호
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• pp.625-643
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• 2021

In this paper, we present a new method to calculate interface warping functions for the analysis of beams with geometric and material discontinuities in the longitudinal direction. The classical Saint Venant torsion theory is extended to a three-dimensional domain by considering the longitudinal direction. The interface warping is calculated by considering both adjacent cross-sections of a given interface. We also propose a finite element procedure to simultaneously calculate the interface warping function and the corresponding twisting center. The calculated interface warping functions are employed in the continuum-mechanics based beam formulation to analyze arbitrary shape cross-section beams with longitudinal discontinuities. Compared to the previous work by Yoon and Lee (2014a), both geometric and material discontinuities are considered with fewer degrees of freedom and higher accuracy in beam finite element analysis. Through various numerical examples, the effectiveness of the proposed interface warping function is demonstrated.

• Geomechanics and Engineering
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• 제22권3호
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• pp.245-254
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• 2020

The interaction between the frozen soil and building structures deteriorates with the increasing temperature. A nuclear magnetic resonance (NMR) stratification test was conducted with respect to the unfrozen water content on the interface and a shear test was conducted on the frozen soil-structure interface to explore the shear characteristics of the frozen soil-structure interface and its failure mechanism during the thawing process. The test results showed that the unfrozen water at the interface during the thawing process can be clearly distributed in three stages, i.e., freezing, phase transition, and thawing, and that the shear strength of the interface decreases as the unfrozen water content increases. The internal friction angle and cohesive force display a change law of "as one falls, the other rises," and the minimum internal friction angle and maximum cohesive force can be observed at -1℃. In addition, the change characteristics of the interface strength parameters during the freezing process were compared, and the differences between the interface shear characteristics and failure mechanisms during the frozen soil-structure interface freezing-thawing process were discussed. The shear strength parameters of the interface was subjected to different changes during the freezing-thawing process because of the different interaction mechanisms of the molecular structures of ice and water in case of the ice-water phase transition of the test sample during the freezing-thawing process.

• Tribology and Lubricants
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• 제29권6호
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• pp.392-396
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• 2013

Biodiesel fuels contain unsaturated fatty acid ester, which can easily oxidize, especially when exposed to ultraviolet light. The products formed by this oxidation give rise to sediment or gum formation. As a result, the fuel can contribute to the corrosion and plugging of the filter pump. Antioxidants have been used in an effort to stabilize biodiesels, but there is still a need for a biodiesel composition with improved oxidation stability. In general, good fuel compositions should provide synergistic combinations of a biodiesel and antioxidants. Our work involved the synthesis of antioxidants to improve the oxidative stability of biodiesel fuel.

• Journal of Magnetics
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• 제16권4호
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• pp.323-327
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• 2011

By means of Monte Carlo simulation, we investigate the effects of interface roughness and temperature on the exchange bias and coercivity in ferromagnetic (FM)/antiferromagnetic (AFM) bilayers. Both exchange bias and coercivity are strongly dependent on interface roughness. For a perfect uncompensated interface a domain wall is formed in the AFM system during FM reversal, which results in a very small exchange bias. However, a finite interface roughness leads to a finite value of the exchange bias due to the existence of pinned spins at the AFM surface adjacent to the mixed interface. It is observed that the exchange bias decreases with increasing temperature, consistent with the experimental results. It is also observed that a bump in coercivity occurs around the blocking temperature.

• Nano
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• 제13권12호
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• pp.1850140.1-1850140.9
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• 2018

An electrochemical sensor ($Cu^{2+}$-IIPs/GCE) was developed for detection of $Cu^{2+}$ in water. $Cu^{2+}$-IIPs/GCE was prepared by dispersing $Cu^{2+}$ imprinted polymers ($Cu^{2+}$-IIPs) on a preprocessed glassy carbon electrode. $Cu^{2+}$-IIPs were synthesized on the surface of modified carbon spheres by ion imprinting technology. The electrochemical performance of $Cu^{2+}$-IIPs/GCE was evaluated by differential pulse voltammetry method. The response of $Cu^{2+}$-IIPs/GCE to $Cu^{2+}$ was linear in $1.0{\times}10^{-5}mol/L$ to $1.0{\times}10^{-3}mol/L$. The detection limit was $5.99{\times}10^{-6}mol/L$ (S=N = 3). The current response value of $Cu^{2+}$-IIPs/GCE was 2.14 times that of the nonimprinted electrode. These results suggest that $Cu^{2+}$-IIPs/GCE can detect the concentration of $Cu^{2+}$ in water, providing a new way for heavy metal ions adsorption and testing.