• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.877-881
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• 2006

We obtained sputtering yields for the MgO, $MgAl_2O_4$ and $MgAl_2O_4/MgO$ films using the FIB system. $MgAl_2O_4/MgO$ protective layers have been found to have less $24^{\sim}^30%$ sputtering yield values from 0.24 atoms/ion up to 0.36 atoms/ion than MgO layers with the values from 0.36 atoms/ion up to 0.45 atoms/ion for irradiated $Ga^+$ ion beam whose energies ranged from 10 keV to 14 keV. And $MgAl_2O_4$ layers have been found to have lowest sputtering yield values from 0.88 up to 0.11. It is also found that $MgAl_2O_4/MgO$ and MgO have secondary electron emission $coefficient({\gamma})$ values from 0.09 up to 0.12 for $Ne^+$ ion whose energies ranged from 50 eV to 200 eV.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.799-801
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• 2003

The secondary electron emission $coefficient({\bullet})$ of vacuum annealed MgO films has been investigated by ${\bullet}$ -focused ion beam(${\bullet}$ -FIB) system. The vacuum annealed MgO films have been found to have higher ${\bullet}$ values than those for as-deposited MgO films for Ne+ ion. Also it is found that the ${\bullet}$ for air-hold of vacuum annealed MgO layers for 24-hours is similar to that for vacuum annealed MgO films without any air-hold.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.358-358
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• 2012

The application of BZO (Boron-doped Zinc Oxide) films use as the TCO(Transparent Conductive Oxide) material for display and solar cell industries, where the conductivity of the BZO films plays a critical role for improvement of cell performance. Thin BZO films are deposited on glass substrates by using RF sputter system. Then charging flow rates of O2 gas from zero to 10 sccm, thereby controlling the impurity concentration of BZO. BZO deposited on soda lime glass and RF power was 300 W, frequency was 13.56 MHz, and working pressure was $5.0{\times}10-6$ Torr. The Substrate and glass between distance 200 mm. We measured resistivity, conductivity, mobility by hall measurement system. Optical properties measured by photo voltaic device analysis system. We measured surface build according to oxygen flow rate from XPS (X-ray Photoelectron Spectroscopy) system. The profile of the energy distribution of the electrons emitted from BZO films by the Auger neutralization is measured and rescaled so that Auger self-convolution arises, revealing the detail structure of the valence band. It may be observed coefficient ${\gamma}$ of the secondary electron emission from BZO by using ${\gamma}$-FIB (Gamma-Focused Ion Beam) system. We observed the change in electrical conductivity by correlation of the valence band structure. Therefore one of the key issues in BZO films may be the valence band that detail structure dominates performance of solar cell devices. Demonstrating the secondary electron emission by the Auger neutralization of ions is useful for the determination of the characteristics of BZO films for solar cell and display developments.

• 한국진공학회지
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• 제21권6호
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• pp.333-341
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• 2012

본 연구는 RF 마그네트론 스퍼터링법을 이용하여 산소유량 변화에 따라 증착된 ITO 박막 구조적, 전기적, 광학적 특성을 분석하였다. ITO (Indium Tin Oxide) 박막은 $1.0{\times}10^{-3}$ Torr의 공정 압력과 2 kW 및 13.56 MHz의 RF 전력, 1,000 sccm의 Ar 가스 조건하에 0~12 sccm의 $O_2$ 가스 유량을 변경하면서 증착하였다. 광투과율 측정은 적분구를 이용하였으며, 측정 파장 범위는 300~1,100 nm이다. 4-point probe를 이용하여 면저항을 측정하였으며, Hall Measurement System을 이용하여 비저항, 캐리어 농도 및 전자이동도를 측정하였다. Scanning electron microscope 장비를 이용하여 ITO 박막 표면을 분석하였고, 박막의 거칠기는 Atomic force microscope을 이용하여 측정하였다. ${\gamma}$-Focused ion beam system을 이용하여 ITO 박막의 이차전자방출계수를 측정하였으며, 이차전자방출계수 값으로 Auger neutralization mechanism 분석법을 이용해 ITO 박막의 일함수를 결정하였다. 3 sccm의 산소 유량에서 증착된 ITO 박막의 비저항은 약 $2.4{\times}10^{-4}{\Omega}{\cdot}cm$로 가장 좋았으며, 광학적 특성 또한 84.93% (Weighted average)로 가장 좋은 것을 확인할 수 있었다. 이 조건에서 이차전자방출 계수가 가장 높았고 일함수는 가장 낮은 경향의 일치함을 확인하였다.

• IMMUNE NETWORK
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• 제13권4호
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• pp.116-122
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• 2013

This study was conducted to determine whether CD4 T cell responses to citrullinated fibrinogen occur in patients with rheumatoid arthritis (RA), especially in HLA-DR4-positive subjects. Whole peripheral blood mononuclear cells (PBMCs) of RA patients and control subjects were stimulated with citrullinated fibrinogen peptides, and T-cell production of proliferation and proinflammatory cytokines, such as interferon-${\gamma}$(IFN-${\gamma}$) and interleukin-17A (IL-17A), were measured. In addition, CD4 T cells from RA patients were stimulated with the citrullinated fibrinogen peptide, $Fib-{\alpha}$ R84Cit, identified as a DRB1*0401-restricted T cell epitope in HLA-DR4 transgenic mice, and the degree of T cell activation was examined similarly. No proliferative responses to the citrullinated fibrinogen peptides were observed in whole PBMCs or CD4 T cells from RA patients. Furthermore, no increased production of IFN-${\gamma}$ or IL-17A was found in whole PBMCs or CD4 T cells stimulated with the citrullinated fibrinogen peptides, although these cells responded to recall antigen, a mixture of tetanus toxoid, purified protein derivative (PPD) from Mycobacterium tuberculosis, and Candida albicans. The results of this study indicate that anti-citrulline immunity in RA patients may be mediated by fibrinogen because there is no evidence of CD4 T cell-mediated immune responses to citrullinated fibrinogen peptides.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2001년도 추계학술발표회 초록집
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• pp.35-35
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• 2001

agnesium Oxide (MgO) with a NaCI structure is well known to exhibit high secondary electron emission, excellent high temperature chemical stability, high thermal conductance and electrical insulating properties. For these reason MgO films have been widely used for a buffer layer of high $T_c$ superconducting and a protective layer for AC-plasma display panels to improve discharge characteristics and panel lifetime. Up to now MgO films have been synthesized by lE-beam evaporation, Molecular Beam Epitaxy (MBE) and Metalorganic Chemical Vapor Deposition (MOCVD), however there have been some limitations such as low film density and micro-cracks in films. Therefore magnetron sputtering process were emerged as predominant method to synthesis high density MgO films. In previous works, we designed and manufactured unbalanced magnetron source with high power density for the deposition of high quality MgO films. The magnetron discharges were sustained at the pressure of O.lmtorr with power density of $110W/\textrm{cm}^2$ and the maximum deposition rate was measured at $2.8\mu\textrm{m}/min$ for Cu films. In this study, the syntheses of MgO films were carried out by unbalanced magnetron sputtering with various $O_2$ partial pressure and specially target power densities, duty cycles and frequency using pulsed DC power supply. And also we investigated the plasma states with various $O_2$ partial pressure and pulsed DC conditions by Optical Emission Spectroscopy (OES). In order to confirm the relationships between plasma states and film properties such as microstructure and secondary electron emission coefficient were analyzed by X-Ray Diffraction(XRD), Transmission Electron Microscopy(TEM) and ${\gamma}-Focused$ Ion Beam (${\gamma}-FIB$).

• Corrosion Science and Technology
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• 제14권2호
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• pp.64-75
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• 2015

Single $TiO_2$ coating prepared by sol-gel process usually experiences cracks in coating layer. In order to prevent cracks, an inorganic-organic hybrid $TiO_2-SiO_2$ coating was synthesized by combining precursors with an organic functional group. Five different coatings with various ratios of (1:8, 1:4, 1:1, 1:0.25 and 1:0.125) titanium alkoxide (TBOT, Tetrabutylorthotitanate) to organo-alkoxysilane (MAPTS, ${\gamma}$-Methacryloxy propyltrimethoxysilane) on carbon steel substrate were made by sol-gel dip coating. The prepared coatings were analyzed to study the coating properties (surface crack, thickness, composition) by scanning electron microscope (SEM), focused ion beam (FIB), and Fourier transform infrared spectroscopy (FT-IR). Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were also performed to evaluate the corrosion characteristics of the coatings. Crack free $TiO_2-SiO_2$ hybrid coatings were prepared with the optimization of the ratio of TBOT to MAPTS. The corrosion rates were significantly decreased in the coatings for the optimized precursor ratio without cracks.

• 한국재료학회지
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• 제26권5호
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• pp.271-280
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• 2016

When a single inorganic precursor is used for the synthesis of a sol-gel coating, there is a problem of cracking on the surface of coating layer. In order to solve this problem of surface cracking, we synthesized inorganic-organic coatings that have hybrid properties of inorganic and organic materials. Sols of various ratios (1:0.07, 0.2, 0.41, 0.82, 1.64, 3.26, 6.54, 13.2) of an inorganic precursor of Tetrabutylorthotitanate ($Ti(OBu)_4$, TBOT) and an organic precursor of ${\gamma}$-Methacryloxy propyltrimethoxysilane (MAPTS) were prepared and coated on stainless steels (SUS316L) by dip coating method. The binding structure and the physical properties of the synthesized coatings were analyzed by FT-IR, FE-SEM, FIB (Focused Ion Beam), and a nano-indenter. Dynamic polarization testing and EIS (electrical impedance spectroscopy) were carried out to evaluate the micro-defects and the corrosion properties of the coatings. The prepared coatings show hybrid properties of inorganic oxides and organic materials. Crack free coatings were prepared when the MAPTS ratio was above a critical value. As the MAPTS ratio increased, the thickness and the corrosion resistance increased, and the hardness decreased.

• Journal of Veterinary Science
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• 제23권3호
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• pp.37.1-37.8
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• 2022

Background: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, resulting in significant economic losses in the poultry industry. Objectives: In this study, the molecular characteristics of two extended-spectrum beta-lactamase (ESBL)-producing APEC isolates were compared with previously reported ESBL-producing E. coli isolates. Methods: The molecular characteristics of E. coli isolates and the genetic environments of the ESBL genes were investigated using whole genome sequencing. Results: The two ESBL-producing APEC were classified into the phylogenetic groups C and B1 and ST410 and ST162, respectively. Moreover, the ESBL genes of the two isolates were harbored in different Inc plasmids. The EC1809182 strain, harboring the bla_CTX-M-55 gene on the plasmid, exhibited extensive homology to IncFIB (98.4%) and IncFIC(FII) (95.8%). The EC1809191 strain, harboring the bla_CTX-M-1 gene, was homologous to IncI1-I (Gamma) (99.3%). All chromosomes carried the multidrug transporter, mdf(A) gene. Mobile genetic elements, adjacent to CTX-M genes, facilitated the dissemination of genes in the two isolates, analogous to other ESBL-producing E. coli isolates. Conclusions: This study clarifies the transmission dynamics of CTX-M genes and supports strengthened surveillance to prevent the transmission of the antimicrobial-resistant genes to humans via the food chain.

• 대한수의학회지
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• 제37권2호
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• pp.451-456
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• 1997

120 heads of korean native calves were examined of serum protein by using cellulose acetate electrophoresis. During 20 days since the calves were purchased, serum protein, fibrinogen values and plasma : fibrinogen ratio were examined in the calves with respiratory and diarrheal disease. The result obtained in this investigation were as follows : 1. Among the 120 heads of calves that were purchased from market, 14 heads(22%) of calves were occurred respiratory disease, and 12 heads(20%) of calves are occurred diarrhea. Occurrence of respiratory disease was 14.5(4~20) days in average and diarrhea was 9.6(2-15) days after they had been purchased. 2. Serum protein fraction were analyzed by cellulose acetate electrophoresis. ${\beta}-globulin$, A/G ratio and ${\beta}_2-globulin$ values were decreased in the calves with respiratory disease. Especially, ${\beta}_2-globulin$ were significantly decreased. In calves with diarrhea, there was no change in ${\beta}-globulin$ values. ${\beta}_2-globulin$ values were higher than that of the normal and respiratory diseased calves. 3. ${\alpha}-globulin$ values were increased in both of calves with diarrhea and respiratory disease. This tendency was due to increase ${\alpha}_2-globulin$ values. 4. The $\gamma$-globulin value of calves with diarrhea was the lowest among the 3 groups. 5. The total protein values of normal calves were $7.0{\pm}1.1g/dl$ and that of respiratory and diarrheal diseased calves were $6.9{\pm}0.9g/dl$ and $6.6{\pm}0.8g/dl$, respectively. Total protein value of calves with diarrhea was lower than that of normal and respiratory diseased calves. Globulin value of calves with diarrhea was the lowest among them. The low value of total protein in diarrheal diseased calves was due to decrease globulin values. 6. The fibrinogen values of calves with respiratory disease ($643{\pm}189mg/dl$) were significantly higher than that of normal calves($533{\pm}135mg/dl$) and calves with diarrhea($572{\pm}188mg/dl$). The plasma : fib. ratio of respiratory diseased calves was $12.0{\pm}4.9$, normal calves was $13.8{\pm}3.5$ and diarrheal diseased calves was $12.8{\pm}4.6$. The ratio of the calves with respiratory disease was significantly decreased.