• Applied Microscopy
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• 제38권2호
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• pp.73-79
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• 2008

현재 생물학 분야에서 세포 구조를 3차로 구현하기 위해 전자 현미경을 이용하는 연구는 매우 빠르게 발전하고 있다. 최근에는 시료의 구조를 변형시키는 화학 고정법 대신 시료를 빠른 시간 내에 동결고정시킴으로써 구조 변형 없이 세포 3차 구조 구현이 가능해졌다. 이러한 기술의 도입으로 단편이미지로만 세포 구조를 이해해왔던 지금까지와 달리 Cryo-ET를 통해 인위적인 구조 변형 없는 3차 구조 구현이 가능해졌고, 이 기법은 약물전달, 나노 공학 등 여러 학문 분야에 활용됨으로써 학문 발전에 이바지 할 것이다.

• Current Photovoltaic Research
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• 제8권4호
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• pp.114-119
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• 2020

In this study, Mitigation of Potential-induced degradation (PID) for PERC solar cells using SiO2 Structure of ARC layer. The conventional PID test was conducted with a cell-level test based on the IEC-62804 test standard, but a copper PID test device was manufactured to increase the PID detection rate. The accelerated aging test was conducted by maintaining 96 hours with a potential difference of 1000 V at a temperature of 60℃. As a result, the PERC solar cell of SiO2-Free ARC structure decreased 22.11% compared to the initial efficiency, and the PERC solar cell of the Upper-SiO2 ARC structure decreased 30.78% of the initial efficiency and the PID reliability was not good. However, the PERC solar cell with the lower-SiO2 ARC structure reduced only 2.44%, effectively mitigating the degradation of PID. Na+ ions in the cover glass generate PID on the surface of the PERC solar cell. In order to prevent PID, the structure of SiNx and SiO2 thin films of the ARC layer is important. SiO2 thin film must be deposited on bottom of ARC layer and the surface of the PERC solar cell N-type emitter to prevent surface recombination and stacking fault defects of the PERC solar cell and mitigated PID degradation.

• Applied Microscopy
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• 제44권2호
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• pp.61-67
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• 2014

Layered structures of fiber cell wall of Korean red pine (Pinus densiflora) were investigated by confocal reflection microscopy (CRM). CRM micrographs revealed detailed structures of the fiber cell wall such as S1, S2, and S3 layers as well as transition layers (S12 and S23 layers), which are present between the S1, S2, and S3 layers. Microfibril angle (MFA) measurement was possible for the S2 and S3 layer in the cell wall. The experimental results suggest that CRM is a versatile microscopic method for investigation of layered structures and MFA measurement in individual sub layer of the tracheid cell wall.

• 한국시뮬레이션학회논문지
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• 제7권2호
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• pp.63-78
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• 1998

The hierarchical cell structure consists of the macrocell and microcells to increase the system capacity and to achieve broad coverage. The hierarchical cell structure provides services for users in different mobility. In this paper, an analytical queueing model in mobile networks is proposed for the performance evaluation of the hierarchical cell structure. The model for networks with the multiple levels can simplify multi-dimensional ones into one-dimensional queueing model. The computational advantage will be growing as the layers are constructed in multiple levels. The computer simulation is provided for validating the proposed analytical model.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.231-238
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• 2006

The performance of free-breathing polymer electrolyte membrane fuel cell (PEMFC) was studied experimentally and the effect of cathode separator structure on the cell performance was investigated. Cathode separators were used for the cell with $18cm^2$ active area. In channel type, the contact resistance is low, and the nature convection. which is strongly affected by the cross-sectional shape of cathode separator channel, is dominant in a cell performance. The maximum power density with $18cm^2$ active area is $105mW/cm^2$ using the 10mm depth and 2mm width channel. A computational analysis was optimum structure of free-breathing channel type PEMFC for robotic application.

• 한국자기공명학회논문지
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• 제15권1호
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• pp.1-13
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• 2011

9Pbw2 is a 9-mer analog of protaetiamycine derived from the larvae of the beetle Protaetia brevitarsis. Previously, we designed four 9-mer peptide analogues to optimize the balance between the hydrophobicity and cationicity of the peptides and to increase bacterial cell selectivity. Among them, 9Pbw2 has high antibacterial activity without cytotoxicity. The results obtained in previous study suggest that the bactericidal action of 9Pbw2 may be attributed to the inhibition of the functions of intracellular components after penetration of the bacterial cell membrane. In order to understand structure-activity relationships, we determined the three-dimensional structure of 9Pbw2 in 200 mM DPC micelle by NMR spectroscopy. 9Pbw2 has one hydrophobic turn helix from $Trp^3$ to $Arg^8$ and positively charged residues at the N- and C-terminus. This result suggested that positively charged residues from position at the C-terminus in 9Pbw2 may be important for the primary binding to the negatively charged phospholipid head groups in bacterial cell membranes and hydrophobic residues in the middle portion face toward the acyl chains of the hydrophobic lipid in the bacterial cell membrane.

• 대한수의학회지
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• 제32권3호
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• pp.295-308
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• 1992

In order to study on the Sertoli cell, we attempt have been made to measure the average number of each germ cells per Sertoli cell on the 12 stages of cycle in matured korean Jindo dog. The fine structure of Sertoli cell junctional specialization was studied with electron microscope. The results were summarized as follows; 1. The average number of various germ cells associated with Sertoli cell was 9.77 to 13. 80 through stages of cycle and the total average number was 11.62. 2. Sertoli-Sertoli cell junctional specialization was present in seminiferous epilthelium, and Sertoli-spermatid cell junctional specialization rose from stage 8 spermatid, persisted to step 13 spermatid and then disappeared. The structure of Sedoli-spermatid cell juncticnal specialization was not similar to that of Sertoli cxlls. 3. Just after spermiation, free-surface of Sertoli-spermatid cell junctional specialization was replaced by Sertoli cell cytoplasm with tubulobulbar complex at the neiglaboring region observed. 4. The Sertoli cell process was located within the cytoplasm of late stage spermatids. Some membranes of residual body and spermatid cytoplasm partly disappeared, resulting in opening of the cytoplasm of spermatid into that Sertoli cell. This fact suggested that spermatid cytoplasm was partly eliminated.

• 대한화학회지
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• 제11권2호
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• pp.60-62
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• 1967

액체에 대한 Significant Structure Theory와 자유부피계산시 수정된 Onno근사법을 사용한 Cill Theory와의 통계역학적 분배함수에 대하여 이론적으로 비교 논의하였다.

• 한국표면공학회지
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• 제41권2호
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• pp.69-75
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• 2008

Electrochemical behaviors of surface modified and MC3T3-E1 cell cultured Ti-30Ta alloys have been investigated using various electrochemical methods. The Ti alloys containing Ta were melted by using a vacuum furnace and then homogenized for 6 hrs at $1000^{\circ}C$. MC3T3-E1 cell culture was performed with MC3T3-E1 mouse osteoblasts for 2 days. The microstructures and corrosion resistance were measured using FE-SEM, XRD, EIS and potentiodynamic test in artificial saliva solution at $36.5{\pm}1^{\circ}C$. Ti-Ta alloy showed the martensite structure of ${\alpha}+{\beta}$ phase and micro-structure was changed from lamellar structure to needle-like structure as Ta content increased. Corrosion resistance increased as Ta content increased. Corrosion resistance of cell cultured Ti-Ta alloy increased predominantly in compared with non cell cultured Ti- Ta alloy due to inhibition of the dissolution of metal ion by covered cell. $R_p$ value of MC3T3-E1 cell cultured Ti-40 Ta alloy showed $1.60{\times}10^6{\Omega}cm^2$ which was higher than those of other Ti alloy. Polarization resistance of cell-cultured Ti-Ta alloy increased in compared with non-cell cultured Ti alloy.

• 한국재료학회지
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• 제12권6호
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• pp.482-487
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• 2002

A $TiO_2$ film for photocatalyst was prepared by anodic oxidation at 180V in acidic electrolyte and film formation mechanism was studied. The major part of anodic $TiO_2$ film consisted of anatase type structure and surface morphology exhibited a porous cell structure. The thickness growth rate of the oxide film with anodization time revealed two-stage slope corresponds to the surface morphology between anodic films. The growth of pores on cell structure and the growth rate of film with two-stage slope are related to the constant formation rate of the $TiO_2$ layer.