• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.305-312
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• 2019

The discovery of nitric oxide (NO) as a major signaling molecule in a number of pathophysiological processes - vasodilation, immune response, platelet aggregation, wound repair, and cancer biology - has led to the development of various exogeneous NO delivery systems. However, the development of ideal delivery system for human body application is still left as a challenge due to its high reactivity and short half-life in physiological condition. In this article, an overview of several nano-structures as potential NO delivery system will be presented, along with their recent research results and biomedical applications. Nano-size delivery system has immense advantages compared to others due to its high surface-to-volume ratio and capability for surface modification; thus, it has been proven to be effective in delivering nitric oxide with enhanced performance. Through this novel nano-structure delivery system, we are expecting to achieve sustained release of nitric oxide within adequate range of concentration, which ensures desired drug effects at the target site. Among different nano-structures, in particular, nanoparticle, microemulsion and nanofilm will be reviewed and compared to each other in respect of nitric oxide release profile. The proposed nano-structures for exogeneous NO delivery have a biological significance in that it can be further utilized in diverse biomedical fields as a highly promising therapeutic method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.601-608
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• 2011

In order to design floating structures, it should be required to evaluate hydrodynamic motions and structural behavior under the wave loadings. Then, structural behavior of floating structures should be evaluated including the effects of wave-induced hydraulic pressure subjected to floating structures. However, there has been a problem to exactly evaluate structural behavior of floating structures since it was difficult to directly connect wave-induced hydraulic pressure resulting from hydrodynamic analysis with structural analysis model. In this study, in order to exactly evaluate structural behavior of floating structures under the wave loading, integrated analysis of hydrodynamic motion and structural behavior was carried out to the large-scaled floating structure. The wave-induced hydraulic pressure resulting from hydrodynamic analysis AQWA were directly mapped to structural analysis model ANSYS bia Workbench interface of ANSYS Inc.. As the results of this study, it was found that the integrated analysis of this study evaluate exactly structural behavior of floating structures under the wave loadings since this method can directly reflect wave-induced hydraulic pressure resulting from hydrodynamic analysis to structural analysis model. Also, as the results of structural behavior evaluation, it was found that the tensile stress on the top slab was maximized at the wave direction of $0^{\circ}$, and tensile stress on the bottom slab was maximized at the wave direction of $45^{\circ}$, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.72-77
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• 2006

This paper presents a comparison of experimental value by electrolytic tank experimental apparatus and calculated value by CDEGS program for potential rise of structure. When a test current flowed through structure models, potential rise was measured and analyzed for types of structure using the electrolytic tank experimental apparatus in real time, and was computed by means of CDEGS program. The structure models were designed and fabricated with four types on a scale of one-one hundred sixty. When the experimental data were compared with the theoretical values, the similar profile was shown. Therefore, the confidence of measurement was obtained. Potential rise was the lowest value at electric cage type(structure model B). The distributions of potential rise are dependent on the resistivity and absorption percentage in concrete attached to structure.

• Applied Microscopy
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• v.36 no.2
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• pp.73-82
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• 2006

Major contributions has been made in cellular ultrastructure studies with the use of high voltage electron microscopy (HVEM) and tomography. Applications of HVEM, accompanied by appropriate image processing, have provided great improvements in the analysis of three-dimensional cellular structures. In the present study, structural patterns of the crystalline bodies that are distinguished in mesophyll plastids of CAM-performing Sedum rotundifolium L., have been investigated using HVEM and tomography. Tilting, and diffraction pattern analysis were performed during the investigation. The titlting was performed at ${\pm}60^{\circ}\;with\;2^{\circ}$ increments while examining serial sections ranging from 0.125 to $1{\mu}m$ in thickness. The young plastids exhibited crystalline inclusion bodies that revealed a peculiar structural pattern. They were irregular in shape and also variable in size. Their structural attributes affected the plastid morphology. The body consisted of a large number of tubular elements, often reaching up to several thousand in number. The tubular elements typically aggregated to form a fluster The elements demonstrated either a parallel or lattice arrangement depending on the sectioning angle. The distance between the elements was approximately 20nm as demonstrated by the diffraction analysis. HVEM examination of the serial sections revealed an occasional fusion or branching of elements within the inclusion bodies. Finally, a three-dimensional reconstruction of the plastid crystalline bodies has been attempted using two different image processing methods.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.367-379
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• 2022

In this paper, a multilayer radar absorbing structure was designed using the Particle Swarm Optimization (PSO) algorithm, and the characteristics of the multilayer radar absorbing structure were analyzed. It was shown that design values can be derived quickly and accurately by applying PSO to the design of a multilayer radar absorbing structure, and it is also shown that the optimal multilayer radar absorbing structure can be designed especially for an oblique incident. In addition, it was shown that the optimal value that meets the performance requirements can be determined even in a combination of various design parameters. It is presented through a comprehensive flowchart including the equations and detailed descriptions of all variables for each step. From the results of this paper, it is possible to omit complex and many calculations for designing a multilayer radar absorbing structure, and it is possible to use various composite materials. It can be utilized in the design and development of multilayer radar absorbing structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.187-192
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• 2013

Thin metallic sandwich plate with pyramidal metallic inner structures is manufactured from a continuous projection welding between face sheets and inner structures. Due to the welding pressure, imperfections of inner structures induced by the deformation of the inner structures occur. The imperfections affect the response of the thin metallic sandwich plate subjected to low-velocity impact loading. The goal of this paper is to obtain a proper dominant imperfection mode of the thin metallic sandwich plate with pyramidal metallic inner structures. The variation of impact responses of the thin metallic sandwich plate for different imperfection modes are investigated by finite element analysis. The results of the FE analysis are compared to those of drop impact experiments. From the results of the comparison, it has been shown that the dominant imperfection mode of the thin metallic sandwich plate with pyramidal metallic inner structures is all type of symmetric imperfection mode with symmetrical imperfections of four struts.

• International Journal of Highway Engineering
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• v.2 no.1
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• pp.135-145
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• 2000

A new procedure needs to be developed to predict the dynamic layer properties under moving truck loads. In this study, a computer code to evaluate layer moduli of asphalt concrete pavement from measured interior deflections at various depths were developed and verified from numerical model tests. Interior deflections of the pavement are measured from Multi-Depth Deflectometer(MDD). It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.32% for several numerical models tested. When impact loads were used, a technique to determine the depth to virtual rigid base was proposed through the analysis of compressive wave velocity and impulse loading durations. It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.114% when virtual rigid base was considered in numerical analysis. The pavement behavior must be evaluated under various vehicle speeds when determining the dynamic interaction between the loading vehicle and pavement system. To evaluate the dynamic behavior on asphalt concrete pavement under various vehicle speeds, truck moving tests were carried out. From the test results with respect to vehicle speed, it was found that the vehicle speed had significant effect on actual response of the pavement system. The lower vehicle speed generates the higher interior deflections, and the lower dynamic modulus.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.179-184
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• 2014

The discharge characteristics of an open dielectric structure were investigated, especially such as a firing voltage and related wall voltage, compared with conventional panel structure based on the Vt close curve measurement in AC plasma display panel. While the front panel of the conventional structure in AC plasma display panel was composed of the glass, electrodes, and dielectric, the open dielectric structure could easily produce the discharge between the scan and the sustain electrodes by erasing the dielectric layer between two electrodes. As the open dielectric structure differ from the conventional structure, various problems were produced when driving with the conventional driving waveform. Especially, due to the changes in the discharge firing characteristics of the open dielectric structure between the scan and the sustain electrodes on the front panel, the conventional reset waveform including the address waveform needed to be modified. In this study, the Vt close curves were measured to compare the discharge firing voltages on three electrodes in the conventional and open dielectric structure and based on the Vt close curve analysis, the modified driving waveform suitable for the open dielectric structure was proposed.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.61-69
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• 2015

나노과학에 대한 다양한 실험적 연구와 이론적 연구가 활발해지고 전문화 되어감에 따라 나노물질에 대해 연구하는 것은 더욱 중요해지고 있는 추세이다. 현재 고분자 나노물질들은 코팅, 광전자 부품, 자기 매체, 세라믹 등에 활발하게 이용되고 있으며 그 활용 범위가 더 커질 것으로 전망된다. 지난 몇 년간 사각기둥 형태의 구조체 내부에서 존재하는 고분자의 움직임에 대한 연구는 다양하게 진행되어왔다. 그러나 고분자들을 더욱 유용하게 응용하여 이용하기 위해서는 나노입자 기술과 연결시켜 보다 다양한 환경에서의 고분자의 상태를 자세하게 이해해야 할 필요가 있다. 고분자 물질에 대한 이론적 연구는 주로 계산이 용이한 거시적인 모델인 코스그레인(Coarse-grained) 모델을 이용한 컴퓨터 시뮬레이션을 통해 이루어져왔다. 본 연구에서도 에디슨 서버에 탑재된 코스그레인 모델을 이용한 분자 모델링 시뮬레이션을 통해 제한된 공간 안에서 다양한 구조체들의 내부에서 고분자의 구조를 계산하고, 시뮬레이션의 결과값과 Flory의 공식을 이용한 이론적인 계산값이 얼마나 잘 맞아 떨어지는지에 대해 알아보고자 한다.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1994.03a
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• pp.24-33
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• 1994

지하구조체를 안전하고 경제적으로 형성시키기 위해서는 구조계 구성인자의 재료특성에 대한 정확한 파악과 구조계의 거동에 대한 정확한 해석이 요구된다. 즉, 실제문제를 수치적으로 모형화하고 구조거동을 이해하기 위해서는 대상 암반체의 초기응력상태와 재료특성을 정확히 반영해야 한다. 이러한 암반의 역학적 특성치는 실험실시험이나 현장시험에 의해 구할 수 있으나, 이는 측정지점 주위의 국부적인 영역에 대한 결과이므로 구조체 전체에 대한 특성을 파악하는데 어려움이 있다. (중략)