• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.144.2-144.2
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• 2016

Diamond-like carbon (DLC) coatings have been widely applied to the mechanical components, cutting tools due to properties of high hardness and wear resistance. Among them, hydrogenated amorphous carbon (a-C:H) coatings are well-known for their low friction properties, stable production of thin and thick film, they were reported to be easily worn away under high temperature. Non-hydrogenated tetrahedral amorphous carbon (ta-C) is an ideal for industrial applicability due to good thermal stability from high $sp^3$-bonding fraction ranging from 70 to 80 %. However, the large compressive stress of ta-C coating limits to apply thick ta-C coating. In this study, the thick ta-C coating was deposited onto Inconel alloy disk by the FCVA technique. The thickness of the ta-C coating was about $3.5{\mu}m$. The tribological behaviors of ta-C coated disks sliding against $Si_3N_4$ balls were examined under elevated temperature divided into 23, 100, 200 and $300^{\circ}C$. The range of temperature was setting up until peel off observed. The experimental results showed that the friction coefficient was decreased from 0.14 to 0.05 with increasing temperature up to $200^{\circ}C$. At $300^{\circ}C$, the friction coefficient was dramatically increased over 5,000 cycles and then delaminated. These phenomenon was summarized two kinds of reasons: (1) Thermal degradation and (2) graphitization of ta-C coating. At first, the reason of thermal degradation was demonstrated by wear rate calculation. The wear rate of ta-C coatings showed an increasing trend with elevated temperature. For investigation of relationship between hardness and graphitization, thick ta-C coatings(2, 3 and $5{\mu}m$) were additionally deposited. As the thickness of ta-C coating was increased, hardness decreased from 58 to 49 GPa, which means that graphitization was accelerated. Therefore, now we are trying to increase $sp^3$ fraction of ta-C coating and control the coating parameters for thermal stability of thick ta-C at high temperatures.

• 한국식품위생안전성학회지
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• 제19권4호
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• pp.193-197
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• 2004

산삼배양추출물의 세균에서의 돌연변이 유발성 검색을 위하여 Salmonella typhimurium의 히스티딘 요구성 균주 LA100, TA1535, TA98 및 TA1537의 4개의 균주와 대장균 Escherichia coli의 트립토판 요구성 균주인 WP2 uvrA를 이용해 복귀돌연변이 시험을 실시하였다 시험물질은 멸균생리식염수에 용해하여 처리하였다. 대사활성계 적용 및 미적용시 모든 균주에 대해 0, 62, 185, 556, 1,667 및 5,000{\mu}g/plate의 범위를 설정하고 각각 음성 및 양성대 조군으로 시험군을 구성해 본 시험을 실시하였다. 시험 결과 모든 균주에서 최고농도에 이르기까지 집락수의 일관성 있는 증가는 나타나지 않았다. 이상의 결과를 종합할 때, 시험물질 산삼배양추출물은 본 시험조건 하에 사용한 시험균주들의 복귀돌연변이를 유발하지 않는 것으로 사료된다.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.219-223
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• 2000

The ferroelectric SBT films were deposited on Pt/Ti/SiO$_2$/Si substrates by liquid injection metalorganic chemical vapor deposition (MOCVD) with single-mixture solution of Sr[Ta(OEt)$_5$(dmae)]$_2$and Bi(C$_6$ 6/H$_5$)$_3$. The Sr/Ta and Bi/Ta ratio in SBT films depended on deposition temperature and mol ratio of precursor in the single-mixture solution. At the substrate temperature of 40$0^{\circ}C$, Sr/Ta and Bi/Ta ratio were close to 0.4 and 1 at precursor mol ratio of 0.5~1.0, respectively. As-deposited film was amorphous. However, after annealing at 75$0^{\circ}C$ for 30 min in oxygen atmosphere, the diffraction patterns indicated polycrystalline SBT phase. The remanent polarization (Pr) and coercive field (Ec) of SBT film annealed at 75$0^{\circ}C$ were 4.7$\mu$C/$\textrm{cm}^2$ and 115.7kV/cm at an applied voltage of 5V, respectively. The SBT films annealed at 75$0^{\circ}C$ showed practically no polarization fatigue up to 10$^10$ switching cycles.

• 한국표면공학회지
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• 제42권4호
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• pp.161-168
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• 2009

Effects of TiN/Ti multilayer coating on the Ti-30Ta-xZr alloy surface were studied by using various experiments. The Ti-30Ta containing Zr (5, 10 and 15 wt%) were melted 10 times to improve chemical homogeneity by using a vacuum furnace. And then samples were homogenized for 24 hrs at $1000^{\circ}C$. The specimens were prepared for TiN/Ti coating by cutting and polishing. The prepared specimens were coated with TiN/Ti multilayers by using DC magnetron sputtering method. The analyses of coated surface and coated layer were carried out by field emission scanning electron microscope(FE-SEM), EDX, and X-ray diffractometer(XRD). From the microstructure and XRD analysis of Ti-30Ta-xZr alloys, The equiaxed structure was changed to needle-like structure with increasing Zr content. And $\alpha$-peak and elastic modulus increased as Zr content increased. The $\alpha$ and $\beta$ phase predominantly were found in the specimen containing high Zr content. According to the analysis of TiN/Ti coating layer, the surface defects and structures of Ti-30Ta-xZr were covered with TiN/Ti coating layer and surface roughness decreased.

• 한국재료학회지
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• 제3권3호
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• pp.310-315
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• 1993

P-type(100)Si Wafer 위에 400$\AA$의 Ta를 증착하여 열산화법으로 ${Ta_2}{O_5}$박막을 형성시킴 후 RTA후처리를 통하여 절연파괴전장 특성 개선을 이루고자 하였다. 유전상수에 미치는 RTA후처리의 영향은 미약하지만 절연파괴전장을 나타내었으나 결정화 온도 이하의 RTA온도에서는 절연파괴전장이 5.4MV/cm로 RTA효과가 크게 나타났다. 이러한 RTA효과는 RTA온도 $575^{\circ}C$에서 flat band voltage shift가 RTA 시간에 따라 변화가 없는 것으로 미루어 보아 RTA효과는 계면 변화에 의한 것이 아님을 알 수 있었으며, RBS 분석을 통하여 ${Ta_2}{O_5}$1박막의 치밀화에 의한 것임을 확인할 수 있었다.

• The Journal of Korean Physical Therapy
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• 제34권1호
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• pp.12-17
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• 2022

Purpose: Ankle dorsiflexion is an essential element of normal functions, including walking, activities of daily living and sport activities. The tibialis anterior (TA) muscle functioned as a dorsiflexor and as a dynamic stabilizer of the ankle joint during walking and jumping. This study aimed to compare TA muscle thickness using ultrasonography according to the four different toe and ankle postures for the selective TA strengthening exercise. Methods: This study were recruited 26 (males: 15, females: 11) aged 20-30 years, with no injury ankle and calf in the medical history, had normal dorsiflexion and inversion range of motion (ROM). The thickness of the TA muscle was measured by ultrasonography in the four different toe and ankle postures: 1. Ankle dorsiflexion with all toe extension and ankle inversion (ITEDF); 2. Ankle dorsiflexion with all toe flexion and ankle inversion (ITFDF); 3. Ankle dorsiflexion with all toe extension and neutral position (NTEDF); 4. Ankle dorsiflexion with all toe flexion and neutral position (NTFDF). One-way repeated analysis of variance (ANOVA) and Bonferroni correction were used to confirm the significant difference among conditions. The level of statistical significance was set at α=0.01. Results: TA muscle thickness with ITFDF was significantly greater than in any other ankle positions, including ITEDF, NTFDF, and NTEDF (p<0.01). Conclusion: Among the four toe and ankle postures, isometric contraction in ITFDF postures showed the greatest increase in thickness of TA rather than ITEDF, NTEDF, and NTFDF postures. Based on these results, ITFDF can be recommended in an efficient way to selectively strengthen TA muscle.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.94.2-94.2
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• 2010

Indium tin oxide (ITO) Thin films were grown on Non-alkarai glass Substrates by PVD method and Subsequently Subjected to ($100^{\circ}C-350^{\circ}C$) Thermal Annealing (TA) In Nitr Oxygen ambinent. Most of all, The effect of TA treatment on the structural properties were studied by using X-Ray diffraction and atomic force microscopy, while optical properties were studied by UV-Transmittance measurements. After TA treatment, the XRD spectra have shown an effective relaxation of the residual compressive stress, As a result, XRD peaks increase of the intensity and narrowing of full width at half-maximun (FWHM). In addtion The microstructure, The surface morphology, the optical transmittance changed and improved, and we investigated The effects of temperature, Time and atmosphere during the TA on the structural and electrical properties of the ITO/glass on TA at $300^{\circ}C$. As a results, the films are highly transparent (80%～89%) in visible region. AFM analysis shows that the films are very smooth with root mean square surface roughness 0.58nm -2.75nm thickness film. It is observed that resistivity of the films drcreases T0 $1.05{\times}10^{-4}{\Omega}cmt$ $6.06{\times}10^{-4}{\Omega}cm$, while mobility increases from $152cm^2/vs$ to $275cm^2/vs$.

• 한국식품영양학회지
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• 제26권4호
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• pp.814-823
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• 2013

This study is carried out to evaluate the genotoxicity of herbs (Angelica decursiva, Polypori umbellate, Astragalus membranaceua, Paeonia iactiflora, Glycyrrhiza uralensis, Cnidium officinale, Rehmannia glutinosa, Cyperus rotundus, Dioscorea batatas and Platycodi Radix) by using the Ames test. The Salmonella typhimurium reversion assay is being performed by using the Sal. typhimurium TA98, TA100, TA102, TA1535 and TA1537 as tester strains. Among 70% of ethanol extracts from 10 herbs, the number of revertant colonies is being increased in Astragalus membranaceua, Cnidium officinale and Dioscorea batatas in a dose-dependent manner, as compared with negative controls of the metabolic activation. In case of dichloromethane and ethyl acetate fraction from 70% of ethanol extracts, the number of revertant colonies is increased in Angelica decursiva, Astragalus membranaceua, Cnidium officinale, Rehmannia glutinosa and Dioscorea batatas in a dose-dependent manner, as compared with negative controls of metabolic activation. Such results indicate that Angelica decursiva, Astragalus membranaceua, Cnidium officinale, Rehmannia glutinosa and Dioscorea batatas all show genotoxic effects when being extracted with the solvent extractions such as 70% of ethanol, dichloromethane and ethyl acetate, and thus, they might be genotoxically- non-safe.

• The Journal of Korean Physical Therapy
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• 제32권4호
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• pp.233-237
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• 2020

Purpose: This study compared the electromyographic activity of the tibialis anterior (TA) and isometric dorsiflexor strength during dorsiflexion according to the toe postures in individuals with ankle dorsiflexor weakness. Methods: Twenty subjects with ankle dorsiflexor weakness participated in this study. The electromyographic activity of the TA and isometric dorsiflexor strength during dorsiflexion between with toe flexion, extension, and neutral postures were measured using an electromyography device and a hand-held dynamometer in individuals with ankle dorsiflexor weakness. One-way repeated measured analysis of variance, and a Bonferroni post hoc test was used. The level of statistical significance was set to α=0.01. Results: The electromyographic activity of the TA was greater with toe flexion during dorsiflexion than with toe extension and neutral postures (p<0.01). The isometric dorsiflexor strength was smaller with toe flexion during dorsiflexion than with toe extension and neutral postures (p<0.01). Conclusions: In individuals with ankle dorsiflexor weakness, the dorsiflexion with toe flexion can help improve the TA electromyographic activity. The toe posture during dorsiflexion for selective TA activation should be considered, especially in individuals with ankle dorsiflexor weakness.

• Toxicological Research
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• 제17권3호
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• pp.235-239
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• 2001

CJ-50005 is an inactivated whole virus vaccine derived from hepatitis A virus (HM175) grown in human MRC-5 diploid fibroblasts cell culture. In order to evaluate the mutagenic potential of CJ-50005, : 3 sets of mutagenicity tests were performed. In the reverse mutation test wing Salmonella typhimurium TA1535, TA1 537, TA98, TA100 and TA102, CJ-50005 did not increase the number of revertants at any concentration tested in this study (2.8, 1.4, 0.7, 0.35 and 0.175 $\mu\textrm{g}$/plate). CJ-50005, at concentration of 2.8, 1.4 and 0.7 $\mu\textrm{g}$/ml, did not increase the number of cells having structural or numerical chromosome aberration in cytogenic test using Chinese Hamster Lung cells. In mouse micronucleus test, no significant increase in the occurrence of micronucleated polychromatic erythrocytes was observed in ICR male and female mice intraperitoneally administered with CJ-50005 at the doses of 25, 12.5 and 6.25 $\mu\textrm{g}$/kg. These results indicate that CJ-50005 has no mutagenic potential in these in vitro and in vivo system.