• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.911-914
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• 2005

Soft tissue characterization and modeling based on living tissues has been investigated in order to provide a more realistic behavior in a virtual reality based surgical simulation. In this paper, we characterize the nonlinear viscoelastic properties of intra-abdominal organs using the data from in vivo animal experiments and inverse FE parameter estimation algorithm. In the assumptions of quasi-linear-viscoelastic theory, we estimated the nonlinear material parameters to provide a physically based simulation of tissue deformations. To calibrate the parameters to the experimental results, we developed a three dimensional FE model to simulate the forces at the indenter and an optimization program that updates new parameters and runs the simulation iteratively. The comparison between simulation and experimental behavior of pig intra abdominal soft tissue are presented to provide a validness of the tissue model using our approach.

• Mass Spectrometry Letters
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• 제9권3호
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• pp.67-72
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• 2018

Alkaline phosphatase (AP) is a membrane-bound glycoprotein that is widely distributed in the plasma membrane of cells of various organs and also found in many organisms from bacteria to humans. The complete amino acid sequence and three-dimensional structure of human placental alkaline phosphatase have been reported. Based on the literature data, AP consists of two presumptive glycosylation sites, at Asn-144 and Asn-271. However, it only contains a single occupied N-linked glycosylation site and no occupied O-linked glycosylation sites. Hydrophilic interaction chromatography (HILIC) has been primarily employed for the characterization of the glycan structures derived from glycoproteins. N-glycan structures from human placental alkaline phosphatase (PLAP) were investigated using HILIC-Orbitrap MS, and subsequent data processing and glycan assignment software. 16 structures including 10 sialylated N-glycans were identified from PLAP.

• 대한수학회보
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• 제50권6호
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• pp.1781-1797
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• 2013

Let x : $M{\rightarrow}\mathbb{R}^n$ be an n - 1-dimensional hypersurface in $\mathbb{R}^n$, L be the Laguerre Blaschke tensor, B be the Laguerre second fundamental form and $D=L+{\lambda}B$ be the Laguerre para-Blaschke tensor of the immersion x, where ${\lambda}$ is a constant. The aim of this article is to study Laguerre Blaschke isoparametric hypersurfaces and Laguerre para-Blaschke isoparametric hypersurfaces in $\mathbb{R}^n$ with three distinct Laguerre principal curvatures one of which is simple. We obtain some classification results of such isoparametric hypersurfaces.

• 연구논문집
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• 통권23호
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• pp.45-56
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• 1993

In order to acquire more comprehensive understanding of textile composites, the processing-microstructure-performance relationships for a variety of material systems, reinforcing schemes and processing technologies should be established. In this paper, emphasis is placed on the integrated analysis of three-dimensional (3-D) 2-step braided composites. The analysis includes the geometric model of unit cells, identification of key process parameters and processing windows due to limiting geometries of yarn jamming, and prediction of elastic constants of the composite. The coordinate transformation and averaging of stiffness and compliance constants are utilized in the prediction of elastic constants. Since there are several types of unit cells in the thickness and width directions of the composites, characterization of mechanical properties is based upon the macro-cell, which occupies the entire cross-section and the unit pitch length of the sample. The performance map demonstrates that a wide range of elastic properties can be achieved by varying the geometric and process parameters.

• 통합자연과학논문집
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• 제2권1호
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• pp.45-49
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• 2009

Electrochemical etching of heavily doped p-type silicon wafers (boron doped, <100> orientation, resistivity; $0.8-1.2m{\Omega}/cm$) with different current density resulting two different refractive indices resulted in DBR (Distributed Bragg Reflectors) porous silicon, which exhibited strong in-plane anisotropy of refractive index (birefringence). Dielectric stacks of birefringent porous silicon acting as distributed Bragg reflectors have two distinct reflection bands depending on the polarization of the incident linearly polarized light. This effect is caused by a three-dimensional (in plane and in depth) variation of the refraction index. Optical characteristics of DBR porous silicon were investigated.

• 대한기계학회논문집A
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• 제33권1호
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• pp.64-71
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• 2009

In this paper, a study on low-velocity impact response of honeycomb sandwich panels was done for the changes of impact location and core fabrication angles. The test specimens were made of glass/epoxy laminate facesheet and aluminum honeycomb core. Square samples of 100mm and 100mm sides were subjected under low-velocity impact loading using instrumented testing machine at three energy levels. Impact parameters like maximum force, time to maximum force, deflection at maximum force and absorbed energy were evaluated and compared for the changes of impact location and core fabrication angle. The impact damage size were measured at facesheet surface by 3-Dimensional scanner. Also, sandwich specimens after impact test were cut to analyse the failure mode.

• Structural Engineering and Mechanics
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• 제60권5호
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• pp.829-849
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• 2016

In this paper, experimental as well as numerical analysis of Glass Fiber Reinforced Polymer (GFRP) laminated composite has been presented under ballistic impact with varying projectile nose shapes (conical, ogival and spherical) and incidence velocities. The experimental impact tests on GFRP composite plate reinforced with woven glass fiber ($0^{\circ}/90^{\circ}$)s are performed by using pneumatic gun. A three dimensional finite element model is developed in AUTODYN hydro code to validate the experimental results and to study the ballistic perforation characteristic of the target with different parametric variations. The influence of projectile nose shapes, plate thickness and incidence velocity on the variation of residual velocity, ballistic limit, contact force-time histories, energy absorption, damage pattern and damage area in the composite target have been studied. The material characterization of GFRP composite is carried out as required for the progressive damage analysis of composite. The numerical results from the present FE model in terms of residual velocity, absorbed energy, damage pattern and damage area are having close agreement with the results from the experimental impact tests.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1409-1410
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• 2008

Layer manufacturing technology has been recently spotlighted as a promising candidate to fabricate porous scaffolds for tissue engineering, because it can provide three dimensional interconnectivity and different pore structures and on-demand scaffold design. This study aims to fabricate HA/PCL composite scaffolds for bone tissue engineering by a layer manufacturing technology, paste extruding deposition, and to characterize in vitro and in vivo biocompatibilities of the scaffolds. This study discusses the mechnical properties, proliferation and differentiation of osteogenic cells, and tissue in-growth and bone regeneration behavior using animal models.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1401-1406
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• 2003

Mechanical behavior of a piezoelectric actuator is studied as a preceding research for the manufacturing of three-dimensional micro-structures. It is needed to examine the simulation of a piezoelectric actuator according to applied direction of voltage, by researching displacement characterization of piezoelectric material through piezoelectric theory. To this end, finite element modeling is employed to study the response of a piezoelectric material under the various input voltages. Where the actuator is simulated by use of ANSYS. To avoid direct contact piezoelectric material with working fluid, silicon, polymer, etc., the actuator is modeled with nickel fixed diaphragm.

• The Korean Journal of Ceramics
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• 제3권3호
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• pp.155-158
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• 1997

Highly oriented diamond films were deposited on a (100) silicon substrate by bias enhanced nucleation technique. Both plan-view and cross-section TEM were applied to study the nucleation and growth mechanism of diamond grains. Randomly oriented polycrystalline diamond grains with internal microtwins were observed at the nucleation stage while defect free regions were retained at the growth stage and were apparently related with the epitaxy of diamond films. From our experimental results, the nucleation and texture formation mechanism of diamond films is discussed.