• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.696-699
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• 1999

The electron transport coefficients in $SF_6+N_2$ gas is analysed in range of E/N values from 100~900(Td) by a Monte Carlo simulation and Boltzmann method, using a set of electron collision cross sections determined by the authors. The result of the Monte Carlo simulation such as electron drift velocity, ionization and electron attachment coefficients, longitudinal and transverse diffusion coefficients in nearly agreement with the respective experimental and theoretical for a range of E/N.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.816-818
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• 2000

본 논문에서는 $SF_6$ 차단기 내의 대전류 아크에 대한 수치적인 해석을 모의하는 도구를 제시한다. 대전류의 차단을 위해서 해석을 통해 열적 파괴를 예측하는 것이 필수적이다. 본 논문에서 사용한 방법은 FVFLIC(finite volume fluid in cells)이며 지배방정식은 압축성 오일러 방정식으로 아크와 유동의 상호 작용을 해석한다. 아크는 기본적으로 에너지 보존식에서 열소스항으로 나타나며 주울열과 복사항으로 표현된다. 주울열은 플라즈마 영역내의 전계해석을 통해 계산되며 복사항은 방출과 흡수항의 합으로 나타내어지고 이것은 국소적인 온도와 압력의 함수이다. 본 논문에서는 수정된 방출과 흡수 모델로 복사 열전달을 계산하였다.

• 유기물자원화
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• 제26권2호
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• pp.75-84
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• 2018

본 연구에서는 하수슬러지의 연료화를 위하여 반탄화 생성물을 분석하였다. 혼합시료는 하수슬러지 함량을 50%로 고정하고, 왕겨와 커피박의 함량을 50%로 조절하여 제조하였다. 반탄화 실험에서 반응 시간(30min, 60min)과 온도($200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$)를 SF(Severity Factor)를 이용하여 단일변수로 나타내었다. 연구 결과 반탄화 조건인 SF가 증가할수록 발열량과 연료비가 증가하였으며, 연소성지수는 감소하는 것을 확인하였다. 혼합시료의 발열량은 커피박(CR)과 반탄화 조건(SF) 모두의 영향을 받는 것으로 나타났으며, 연료비 범위는 SF가 6.19보다 낮은 경우 갈탄의 연료비 범위(0.5~1.0)와 유사하나 SF가 7.36보다 큰 경우 저도역청탄의 연료비 범위(1.0~1.8)와 유사한 것을 확인하였다. 연소성지수는 커피박보다는 왕겨가 더 함유될수록 낮은 조건의 SF에서 안정 범위(3,000~5,500kcal/kg)의 값을 나타내는 것으로 확인되었다.

• Journal of Microbiology
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• 제42권1호
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• pp.25-31
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• 2004

Sf9 cells have obvious advantages for the conventional production technology of vaccine. They are useful tools for high concentration and large-scale cultures. Sf9 cells were grown to maximal concentration, 8${\times}$l0$\^$6/ cells/$m\ell$ in a 500$m\ell$ spinner flask, with a doubling time at the exponentially growing phase of 24.5 hours, using serum-free media. To explore the ability of Sf9 cells to be infected by the Japanese encephalitis (JE) virus Beijing-l strain, Sf9 cells were infected with the virus. By 4-5 days post-infection, 10-15 % of the Sf9 cells showed cytopathic effect (CPE), from granularity to the formation of syncytia and multinucleated giant cells continuously observed over a period of 35 days. Positive fluorescent reactions were detected in 30-40% of cells infected with the JE virus Beijing-l strain, and the uninfected Sf9 cells were completely negative. Virus particles, propagated in Sf9 and Vero cells, were concentrated by sedimentation on 40% trehalose cushions by ultracentrifugation, and showed identical patterns of viral morphogenesis. Complete virus particles, 40 to 50 nm in diameter, were observed, and JE virus envelope (E) proteins, at 53 kDa, were found in the western blot analysis to the anti-JE virus E protein monoclonal antibody and reacted as a magenta band in the same position to the glycoprotein staining. To evaluate whether the infectious virus was produced in Sf9 cells inoculated with the JE virus Beijing-l stain, Sf9 cells were inoculated with the virus, and sample harvested every 5 days. The titers of the JE virus Beijing-l strain rose from 1.0${\times}$l0$\^$5/ to 1.5${\times}$l0$\^$6/ pfu/$m\ell$. The infected Sf9 cells could be subcultured in serum-free medium, with no change in the plaque sizes formed by the JE virus Beijing-l strain in the plaque assay. It is suggested that the ability of the JE virus Beijing-l strain to infect Sf9 cells in serum-free media will provide a useful insect cell system, where the JE virus replication, cytopathogenicity and vaccine immunogen can be studied.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.168-171
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• 1999

This paper describes the influence of conducting particle within the coaxial cylindrical electrodes gap under alternating voltage condition investigated using charge simulation method. If the conducting particles precent in the gas insulated system, they can cause decrement of breakdown voltage. Thus, three dimensions computations of electric fields and electrostatic forces have been carried out according to particle location. The results show a good agreement with those of outside country, which can offer a practical reference on the insulation design of domestic GIS.

• Advances in concrete construction
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• 제6권4호
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• pp.323-344
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• 2018

The study herein reports the impact of Steel Fiber (SF) and Ground Granulated Blast Furnaces slag (GGBFS) content on the fresh and hardened properties of fly ash (FA) based Self-Compacting Geopolymer Concrete (SCGC). Two series of self-compacting geopolymer concrete (SCGC) were formulated with a constant binder content of $450kg/m^3$ and at an alkaline-to-binder (a/b) ratio of 0.50. Fly ash (FA) was substituted with GGBFS with the replacement levels being 0%, 25%, 50%, 75%, and 100% by weight in each SCGC series. Steel fiber (SF) wasn't employed in the assembly of the initial concrete series whereas, within the second concrete series, an SF combination was achieved by a constant additional level of 1% by volume. Fresh properties of mixtures were through an experiment investigated in terms of slump flow diameter, T50 slump flow time, V-funnel flow time, and L-box height ratio. Moreover, the mechanical performance of the SCGCs was evaluated in terms of compressive strength, splitting tensile strength, and fracture toughness. Furthermore, a statistical analysis was applied in order to judge the importance of the experimental parameters, like GGBFS and SF contents. The experimental results indicated that the incorporation of SF had no vital impact on the fresh characteristics of the SCGC mixtures whereas GGBFS aggravated them. However, the incorporation of GGBFS was considerably improved the mechanical properties of SCGCs. Moreover, the incorporation of SF with the total different quantity of GGBFS replacement has considerably increased the mechanical properties of SCGCs, by close to (65%) for the splitting strength and (200%) for compressive strength.

• The Journal of Korean Physical Therapy
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• 제19권5호
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• pp.29-41
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• 2007

Purpose: The aim of this study was to examine the validity and reliability on Psychometric Arthritis Impact Measurement Scale-Short Form (AIMS-SF) in patients with knee osteoarthritis(OA). Methods: The sample consisted of 62 patients who had received physical therapy at the physical therapy units of the Andong Medical Center, Sungso Hospital, Ahn Orthopedic Surgery Clinic, and St. Luke Clinic in Andong city in June 2006. Questionnaire on the AIMS-SF was recruited by 5 physical therapists. The internal structure and reliability of the scales were evaluated by means of item-internal consistency(Cronbach's alpha coefficient: ${\alpha}$), item-discriminant validity, Pearson's relation coefficient. To explore construct validity we conducted a principal component factor analysis with varimax rotation analysis. The criterion for factor extraction was an eigenvalue >1.0. Results: 62 OA patients's an average $age{\pm}standard$ deviation was $53.8{\pm}14.4$ years (range: $40{\sim}81$ yr). The internal consistency reliability of 11 items, as estimated by Cronbach's ${\alpha}$ coefficient, was high ranging $0.60{\sim}0.78$ (except for 0.40 for mobility level and -0.48 for mood). The internal consistency reliability of item-each scale was also high $0.82{\sim}0.93$ (except for 0.48 for mood). Of 11 items, the item-discriminant validity on 6 items was high (${\alpha}$ coefficient range: $0.11{\sim}0.25$), however, others (0.57 for tension level, 0.48 for arthritis pain, 0.41 for walking and bending, and 0.40 for work) were a little low. The construct validity by factor analysis was a little low. Conclusion: In conclusion, the results reported here confirm the validity and reliability of the AIMS-SF in patients with OA of the knee. The Collection of information on health status using this instrument was acceptable to patients. A further prospective multi-center study will be necessary to prove the construct validity.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.72-77
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• 2021

The radial distribution of etch rate was analyzed using the ion energy flux model in VHF-CCP. In order to exclude the effects of polymer passivation and F radical depletion on the etching. The experiment was performed in Ar/SF6 plasma with an SF6 molar ratio of 80% of operating pressure 10 and 20 mTorr. The radial distribution of Ar/SF6 plasma was diagnosed with RF compensated Langmuir Probe(cLP) and Retarding Field Energy Analyzer(RFEA). The radial distribution of ion energy flux was calculated with Bohm current times the sheath voltage which is determined by the potential difference between the plasma space potential (measured by cLP) and the surface floating potential (by RFEA). To analyze the etch rate uniformity, Si coupon samples were etched under the same condition. The ion energy flux and the etch rate show a close correlation of more than 0.94 of R² value. It means that the etch rate distribution is explained by the ion energy flux.

• Journal of Ginseng Research
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• 제41권3호
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• pp.386-391
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• 2017

Background: Korean Red Ginseng (KRG) is an ethnopharmacological plant that is traditionally used to improve the body's immune functions and ameliorate the symptoms of various diseases. However, the antitumorigenic effects of KRG and its underlying molecular and cellular mechanisms are not fully understood in terms of its individual components. In this study, in vitro and in vivo antitumorigenic activities of KRG were explored in water extract (WE), saponin fraction (SF), and nonsaponin fraction (NSF). Methods: In vitro antitumorigenic activities of WE, SF, and NSF of KRG were investigated in the C6 glioma cell line using cytotoxicity, migration, and proliferation assays. The underlying molecular mechanisms of KRG fractions were determined by examining the signaling cascades of apoptotic cell death by semiquantitative reverse transcriptase polymerase chain reaction and Western blot analysis. The in vivo antitumorigenic activities of WE, SF, and NSF were investigated in a xenograft mouse model. Results: SF induced apoptotic death of C6 glioma cells and suppressed migration and proliferation of C6 glioma cells, whereas WE and NSF neither induced apoptosis nor suppressed migration of C6 glioma cells. SF downregulated the expression of the anti-apoptotic gene B-cell lymphoma-2 (Bcl-2) and upregulated the expression of the pro-apoptotic gene Bcl-2-associated X protein (BAX) in C6 glioma cells but had no effect on the expression of the p53 tumor-suppressor gene. Moreover, SF treatment resulted in activation of caspase-3 as evidenced by increased levels of cleaved caspase-3. Finally, WE, SF, and NSF exhibited in vivo antitumorigenic activities in the xenograft mouse model by suppressing the growth of grafted CT-26 carcinoma cells without decreasing the animal body weight. Conclusion: These results suggest that WE, SF, and NSF of KRG are able to suppress tumor growth via different molecular and cellular mechanisms, including induction of apoptosis and activation of immune cells.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.27-30
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• 2011

A sub-cooled liquid nitrogen cooling system is known as a most promising method to develop large scale superconducting apparatuses such as superconducting fault current limiters and superconducting cables [1]. Gaseous helium (GHe), gaseous nitrogen ($GN_2$) and sulfur hexafluoride ($SF_6$) are commonly used for designing an high voltage applied superconducting device as an injection gaseous medium [2, 3]. In this paper, the analysis on the dielectric characteristics of GHe, $GN_2$ and $SF_6$ are conducted by designing and manufacturing sphere-to-plane electrode systems. The AC withstand voltage experiments on the various gaseous insulation media are carried out and the results are analyzed by using finite element method (FEM) considering field utilization factors (${\xi}$). It is found that the electric field intensity at sparkover ($E_{MAX}$) of insulation media exponentially decreases according to ${\xi}$ increases. Also, the empirical expressions of the functional relations between $E_{MAX}$ and ${\xi}$ of insulation media are deduced by dielectric experiments and computational analyses. It is expected that the electrical insulation design of applied superconducting devices could be performed by using the deduced empirical formulae without dielectric experiments.