• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1512-1521
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• 1991

본 연구에서는 유속과 압력등이 시간과 위치의 함수로 표현되는 비정상 유체 가 흐를 때 그 유동 특성이 파이프계에 미치는 영향을 고찰하기 위해 비정상 유동을 포함한 파이프계의 운동방정식을 유도하고 유동 변수가 파이프계의 안정성에 미치는 영향을 연구하였다.

• KSBB Journal
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• v.19 no.3
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• pp.221-225
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• 2004

Bacillus polyfermenticus SCD derived from Bacillus sp., which is commonly called as Bisroot$^{ⓡ}$. The goal of this study, is to Increase stability of Bacillus polyfermenticus SCD in low pH, high temperature and high glucose concentration via three layer coating. The viability of coated Bacillus polyfermenticus SCD increased to 30%, 20%, 14% in the condition of pH 2 4 6 than that of uncoated Bacillus polyfermenticus SCD at 37$^{\circ}C$ for 4 h. Final viability of the coated Bacillus polyfermenticus SCD in 80$^{\circ}C$ increased to 40% than that of uncoated Bacillus polyfermenticus SCD. In high glucose concentration coated Bacillus polyfermenticus SCD is more stable than uncoated about 50%. In conclusion, the three layer coated Bacillus polyfermenticus SCD is very stable for low pH, high temperature and high glucose concentration.

• The Korean Journal of Nuclear Medicine
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• v.39 no.5
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• pp.278-283
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• 2005

Purpose: In prior study, we synthesized $^{99m}Tc$-galactosylated chitosan (GC) and performed in vivo biodistribution study, showed specific targeting to hepatocyte. The aim of this study is to evaluate the labeling efficiency and cytotoxicity of modified galactosylated chitosan compounds, galactosyl methylated chitosan (GMC) and HYNIC-galactosylated chitosan (GCH). Materials and Methods: GC, GMC and GCH were synthesized and radiolabeled with $^{99m}Tc$. Then, they were incubated for 6 hours at room temperature and human serum at $37^{\circ}C$. Labeling efficiencies were determined at 15, 30 m, 1, 2, 3 and 6 h after radiolabeling. To evaluate cytotoxicity, MTT assay was performed in HeLa and HepG2 cells. Results: In comparison with them of $^{99m}Tc$-GC labeling efficiencies of $^{99m}Tc$-GMC were significantly improved (100, 97 and 89%) in acetone and 96.3, 95.8 and 75.6% in saline at 15 m, 1 and 6 h, respectively). Moreover, $^{99m}Tc$-GCH showed more improved labeling efficiencies (>95% in acetone and human serum and >90% in saline at 6 h). In MTT assay, cytotoxicity was very low and not different from that of controls. Conclusion: These results represent that these compounds are radiochemically compatible radiopharmaceuticals, can be used in hepatocyte specific imaging study and in vivo gene or drug delivery monitoring.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.188-194
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• 1999

We synthesized the nonlinear optical (NLO) PI-SOT(polyimide system, 4-[N,N-bis(hydroxyethyl)amino-4,-($\beta$-cyano-$\beta$-methylsulfonyl)vinyl]azobenzene) polymer with high electro-optic coefficients as well as good thermal and temporal stabilities of the elector-optic coefficient ${\gamma}_33$ by the simple Mitsunobu reaction. By using the simple reflection method of C. C. Teng, we measured the thermal and temporal stabilities of the electro-optic coefficient ${\gamma}_33$ of corona-poled PI-SOT polymer at the wavelength of 632.8 nm and 852 nm, respectively. At the temperature of $20^{\circ}C$, the electro-optic coefficient ${\gamma}_33$ of corona-poled PI-SOT polymer were 25.12 pm/V at the wavelength of 632.8 nm and 5.40 pm/V at the wavelength of 852 nm. These values were highly stabilized for more than 60 days at 2$0^{\circ}C$ and stabilized within 6% for more than 10 hours at $100^{\circ}C$.

• 한국체육학회지인문사회과학편
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• v.55 no.4
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• pp.507-516
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• 2016

The purpose of this study is to identify the effects of PPARβ/δ over-expression on PGC-1α mRNA and protein stability after single bout of swimming exercise in mice skeletal muscle. Empty vector (EV) or PPARβ/δ was over-expressed in tibialis anterior(TA) using electroporation(EPO) technique to compare with non-treatment muscle(control; Con). TA muscles were dissected at 0h, 24h or 54h after termination of exercise. PGC-1α mRNA in Con, EV and PPARβ/δ over-expressed muscles were increased 6.8 fold (p<.001), 6.2 fold(p<.001) and 7.1 fold(p<.001), respectively, than sedentary(Sed) group at 0h after exercise and then reverted to Sed group levels at 24h and 54h after termination of exercise. PGC-1α and PGC-1α ubiquitination in EV treated muscles were increased 2.2 fold and 1.74 fold, respectively, than Sed group at 24h after termination of exercise, and then reverted to Sed group levels at 54h after termination of exercise. PGC-1α in PPARβ/δ over-expressed muscles at 24h and 54h after termination of exercise were increased 2.5 fold and 2.2 fold, respectively, than Sed group, but PGC-1α ubiquitination was not increased at 24h and 54h after termination of exercise. Our results indicate that PPARβ/δ over-expression does not increase PGC-1α mRNA stability, but increase PGC-1α protein stability through post-translation mechanism after termination of exercise.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.4 s.310
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• pp.35-44
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• 2006

The network induced transmission delay deteriorates the performance and stability of the real-time distributed control system on LonWorks over IP (LonWorks/IP) virtual device network (VDN). LonWorks/IP virtual device network is an integrated form of LonWorks device network and IP data network. The time delay in servo control on the LonWorks/IP-based VDN has highly stochastic nature. In the real-time distributed servo applications for predictive maintenance on the factory floor, timely response is essential.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.407-411
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• 1997

Effects of heating time and storage temperature on the oxidative stability of heated palm oil were studied. Palm oil was heated at $150^{\circ}C$ for 0, 1, 10 or 20 min and stored at 4, 20 or $65^{\circ}C$. The oxidative stability of the sample was evaluated by determining peroxide value of the oil and measuring the volatiles in the headspace of the sample. Significant difference in the peroxide or volatile formation was observed (p<0.05) in heated palm oils between samples stored at 4 or $20^{\circ}C$ and those stored at $65^{\circ}C$. Pentane, hexanal, heptane and total volatiles increased with heating time, while storage temperature did not significantly affect their formation, indicating that heating time played more important role in volatile formation in the heated palm oil than storage temperature. However, adverse results were observed for the formation of peroxide. The interaction effect of heating time and storage temperature on the oxidative stability of heated palm oil was also observed.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.25-31
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• 2009

This study was conducted to characterize the relationship of rainfall intensity and slope stability by using numerical analysis. The maximum precipitation rate for 10 minutes, 1 hour and 1 day was determined as 28 mm, 70 mm and 271 mm, respectively, by investigating 36 years of KMA data. Then slope infiltration analysis was performed to obtain the ground water level in the slope by using computer programming SEEP/W, and slope stability analysis was done for each time step by using program SLOPE/W. The factor of safety was minimized when the slope was saturated under each rainfall intensity; the time required for saturation was 2 hours with 10 minutes rainfall intensity of 28 mm, 7 hours with 1 hour rainfall intensity of 70 mm and 3 days with 1 day rainfall intensity of 271 mm. When accumulated rainfall was 196 mm for the 10minutes rainfall intensity of 28 mm with duration of 2 hours, the factor of safety was decreased to 1.0, while accumulated rainfall of 468 mm and 820 mm for the 1 hour and 1 day rainfall intensity, respectively, was required to reach the factor of safety, 1.0. Since the normalized rainfall intensity was 13 mm and 1.9 mm for 1 hour and 1 day maximum rainfall, respectively, those results showed that the rainfall intensity could have a more effect on the slope stability than the accumulated rainfall.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.163-167
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• 2008

This paper presents pressure fluctuation characteristics of a 30 ton-f class liquid rocket engine combustor. Combustion stability of the combustor was evaluated using the results 46 firing tests performed with a varying O/F ratio and chamber pressure. The RMS value of pressure fluctuation during the steady state combustion was less than 2.6% of the static chamber pressure, demonstrating static stability of the combustion phenomenon. The decay time of pressure fluctuation caused by forced disturbance of a pulse gun was found to be less than 3.5 msec verifying dynamic stability of the combustor.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.333.1-333.1
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• 2014

이번 연구는 비정질 인듐-갈륨-아연-산화막(IGZO)을 이용한 박막트랜지스터(TFT)의 열처리 분위기에 따른 전기적 특성을 비교하는 것이다. IGZO의 열처리 시 널리 용하는 Air 분위기 뿐만 아니라, 순수한 N2 및 O2 분위기에서 전기적 특성(Ion/Ioff, S.S 기울기 및 V등)이 어떻게 변하는지를 1차적으로 비교 분석하며, 추후 심화 단계로 gate bias stress가 TFT에 미치는 영향을 확인하였다. 우선 열처리 분위기에 따른 특성을 확인하였다. N2분위기의 경우 다른 분위기와 아주 조금의 차이는 있으나 열처리를 하지 않은 경우를 제외한 나머지는 전체적으로 유사하였다. 좀 더 자세히 보면 두번째의 경우 Forward와 Reverse의 경우 전체적으로 모두 유사해 보였고, 특히 N2분위기의 경우 가장 안정적임을 알 수 있었다. 또 Stress Time에 따른 V의 변화량을 측정하였는데 역시 열처리를 하지 않은 경우에는 시간이 지날수록 변화가 크게 나타나 안정성에 문제가 있었다. 하지만 Air, N2, O2분위기에서는 약간의 미세한 차이는 있으나 전체적으로 유사하였다. 마지막으로 IGZO의 특성상 저온열처리를 하는 경우가 많은데 이러한 경우에는 열처리 시간에 따라 Stress Time의 변화에 따른 V차이를 확인하였다. 실험 결과 열처리 시간이 길어질수록 Stress Time에 따른 V의 변화가 작게 나타났다. 이를 통해 저온의 경우 약 5~8시간의 열처리를 한 경우가 안정적이라는 결론을 얻을 수 있었다.