• 한국초전도ㆍ저온공학회논문지
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• 제14권2호
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• pp.24-27
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• 2012

The superconducting coil system is one of the most important components in Korea Superconducting Tokamak Advanced Research (KSTAR), which has been operated since 2008. $Nb_3Sn$ and NbTi superconductors are being used for cable-in-conduit conductors (CICCs) of the KSTAR toroidal field (TF) and poloidal field (PF) coils. The CICCs are cooled by forced-flow supercritical helium about 4.5 K. The temperature, pressure and mass flow rate of the supercritical helium in the CICCs are interacting with each other during the operation of the coils. The complicate behaviors of the supercritical helium have an effect on the operation and the efficiency of the helium refrigeration system (HRS) by means of, for instance, pressure drop. The hydraulic characteristics of the supercritical helium have been monitored while the TF coils have stably achieved the full current of 35 kA. In other hands, the PF coils have been operated with various pulsed or bipolar mode, so the drastic changes happen in view of hydraulics. The heat load including AC loss on the coils has been analyzed according to the measurement. These activities are important to estimate the temperature margin in various PF operation conditions. In this paper, the latest hydraulic behaviors of PF coils during KSTAR operation are presented.

• 대한본초학회지
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• 제39권3호
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• pp.57-67
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• 2024

Objectives : The aim of this study is to evaluate the potential biological activity of Veronica incana extracts (VIE) through in vitro, ex vivo, and in vivo experiments. Methods : In vitro, we conducted analyses on the total polyphenol (TP) and total flavonoid (TF) levels, alongside DPPHand ABTS radical scavenging activities. Ex vivo evaluations on adipose tissue measured glycerol release as a marker of lipolysis. In LPS-induced RAW 264.7 cells, we quantified nitric oxide (NO) production. Following H₂O₂ induction in U2OS cells, we performed mitochondrial assays such as MitoSox and MitoTracker. Moreover, Bodipy assays were conducted in 3T3-L1 cells. In vivo, we performed anti-osteoarthritis effect of VIE against monosodium iodoacetate (MIA)-induced osteoarthritis in rats. Results : The results presented encompass a myriad of models, from cell culture to animal experiments as well as ex vivo studies. VIE demonstrated high TP and TF contents, potent DPPH and ABTS scavenging activities, and regulated glycerol release. Moreover, the inhibition of NO production in LPS-induced inflammation was notably confirmed and the reduction of lipid droplets was distinctly shown. Furthermore, in H₂O₂-induced U2OS cells, MitoSox was effectively reduced while MitoTracker noticeably increased. In vivo assays confirmed a significant increase in hindpaw weight distribution (HWD) decreased by MIA after VIE treatment. Additionally, VIE inhibited serum inflammatory cytokines (TNF-𝛼, IL-6, and IL-1𝛽) and MDA levels in joint tissue. Conclusion : In conclusion, Veronica incana exhibited various pharmacological effects including antioxidant, anti-obesity, and anti-inflammatory properties.

• BMB Reports
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• 제50권11호
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• pp.537-538
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• 2017

Hypoxia affects various physiological and pathophyological processes. Hypoxia changes the expression of hypoxia-responsive genes through two main pathways. First, hypoxia activates transcription factors (TF) such as Hypoxia-inducible Factor (HIF). Second, hypoxia decreases the activity of Jumonji C domain-containing histone demethylases (JMJDs) that require $O_2$ and ${\alpha}$-Ketoglutarate (${\alpha}$-KG) as substrates. The JMJDs affect gene expression through their regulation of active or repressive histone methylations. Profiling of H3K4me3, H3K9me3, and H3K27me3 under both normoxia and hypoxia identified 75 TFs whose binding motifs were significantly enriched in the methylated regions of the genes. TFs showing similar binding strengths to their target genes might be under the 'metabolic control' which changes histone methylation and gene expression by instant changing catalytic activities of resident histone demethylases.

• 한국식품영양학회지
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• 제30권5호
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• pp.1025-1034
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• 2017

As the consumption of wheat has increased recently, the number of people who have digestive problems resulting from gluten in wheat has also increased. Teff has an attractive nutritional profile, as it not only gluten-free but also high in dietary fiber, protein, iron, and calcium. Seven samples were prepared for this study. The quality characteristics of gluten-free noodles were evaluated based on pH, salinity, water absorption, turbidity, color, texture properties, tensile strength, and SEM. The pH value was the highest in TF100 with a pH of 6.66 and the lowest in the control with a pH of 6.42. Salinity showed no significant difference among all samples, and it ranged from 0.02~0.04% (p<0.05). Water absorption was the highest in TFX with a value of 66.11%, and the lowest in the control with a value of 44.81%. Turbidity showed no significant difference among all samples, and it ranged from 0.14~0.21 O.D. (p<0.05). While the lightness and yellowness values decreased with an increase in teff flour content, the redness value tended to decrease. The color difference value was the highest in the sample group without gluten. Based on the texture profile analysis, the hardness was highest in the control with a value of 46.74 N and lowest in TF100 with a value of 18.34 N. The springiness showed no significant difference among all samples. The cohesiveness was highest in the control with a value of 0.92 N. The chewiness decreased with an increase in teff flour content. Although the control with gluten had the highest tensile strength at $3.42kg/cm^2$, TFX had considerable tensile strength at $2.30kg/cm^2$. This study demonstrated the processability of gluten-free noodles using teff flour.

• 한국전기전자재료학회논문지
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• 제34권1호
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• pp.1-7
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• 2021

This study investigated the structural, dielectric, ferroelectric, and strain properties of (0.98-x)Bi1/2Na1/2TiO3-0.02BiFeO3-xSrTiO3 (BNT-BF-100xST, x＝0.20, 0.22, 0.24, 0.26, and 0.28). All samples were successfully synthesized using the conventional solid-state reaction method and sintered at 1,175℃ for 2 h. The average grain size of the BNT-BF-100x ceramics decreased with increasing ST content. Furthermore, we observed that the ferroelectric- relaxor transition temperature (TF-R) decreased with increasing ST content, which eventually vanished in the BNT-BF-24ST ceramics. The results indicated that a ferroelectric to relaxor phase transition could be induced by ST modification. Consequently, a large electromechanical strain of 633 pm/V at 4 kV/mm was observed for the BNT-BF-26ST ceramics. These results imply that our materials have the competitive advantage of larger strain under lower operating field conditions compared with other BNT-based lead-free piezoelectric ceramics. We expect that BNT-BF-ST lead-free piezoelectric ceramics are promising candidates as a novel ternary BNT-based system and can find potential applications in actuators.

• 항공우주시스템공학회지
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• 제13권1호
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• pp.54-61
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• 2019

3D프린팅은 '12년 세계경제포럼에서 떠오르는 10대 기술 중 2번째로 선정이 되었고 기존 산업의 패러다임을 변화시켜 제조업 혁신과 신 시장을 창출할 핵심기술로 대두되었다. 미국 등 주요 선도 국가들은 3D 프린팅을 국방 분야에 적극 확대해 나가고 있으며, 우리나라 역시 3D 프린팅의 군사적 활용을 위해 국방 수리부품 생산기술 확보 및 국방전문인력 양성을 추진하고 있다. 이에 본 논문은 기존의 무기체계 개발단계, 양산단계, 운영유지단계의 부품 국산화 개발관리 절차를 활용하여 향후 신뢰성 있는 3D 프린팅 수리부품을 효율적으로 작전현장에 적용하기 위한 방안을 제시하였다.

• 한국작물학회지
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• 제55권4호
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• pp.284-291
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• 2010

고 고형분함량 감자 생산을 위한 수확시기를 예측하는 데 있어 에너지 소모량의 추정에 대한 연구결과는 다음과 같다. 1. 각 지역별로 포장의 파종시기부터 수확시기까지 최근 5년간(2005년~2009년) 평균기온, 강수량, 상대습도, 일조시간, 바람, 지중온도 등의 농업환경을 조사한 결과 파종기 저온피해와 괴경비대기 장마기간을 회피한다면 가공용 원료감자는 가공품 생산에 필요시마다 물량을 수급하기 때문에 만숙재배를 하지 않아 품종의존도가 낮아 수확시기의 환경에 대한 비중이 큰 것으로 판단되었다. 2. 파종시기부터 출현까지에는 지중온도에 영향을 많이 받아 지역별 편차가 심해 시뮬레이션에서는 출현시기를 기준으로 감자의 수확적기를 예측하는 것이 바람직하였다. 3 수확시기를 예측하기 위한 생장모형은 $Tp=\frac{Tm{\cdot}Wm^{Tp}}{Wm^{Tm}}$를 사용하고, 생장량 Wm을 계상하는 기본 생장모형은 $Wm={\int}^m_tf(x)dt$를 사용하였다. 4. 기본 생장모형을 통해 Wm을 계상할 때는 광합성율(${\Delta}A$)과 식물체내 에너지 소모(${\Delta}E$) 개념을 적용해야 보다 정밀한 수확시기를 예측할 수 있었으며, 식물체내 에너지 소모에 대한 정의는 기후변화에 대응하여 농업환경에 대처하는 식물체내 에너지 소모를 계상하는 것으로 최근 5년간(2005년~2009년) 수확시기에 따라 고형분함량을 측정한 결과 광합성율만 계상할 때 보다 에너지 소모개념을 적용한 것이 효과적이었다.

• 미생물학회지
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• 제35권3호
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• pp.237-241
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• 1999

페놀수지 폐수는 41,000 mg/l 의 페놀과 2,800 mg/l 의 포름알데히드를 포함하고 있어 직접적인 생물학적 처리가 어렵다. 자연계에서 분리된 Candida tropicalis PW-51 은 100 mg/l 이하의 포름알데히드 존재하에서 1,000 mg/l 의 페놀을 분해하였으나 포름알데히드의 농도가 증가함에 따라 페놀분해는 저해되었다. 페놀수지 폐수를 1/40 희석하였을 때 페놀류 화합물 농도가 882 mg/l 이었는데, 회분배양 후 페놀농도는 81 mg/l로 약 91% 분해되었다. 폐수를 1/40, 1/20 희석한 후 C.tropicalis PW-51에 의해 생물학적으로 연속처리한 결과 페놀류 화합물은 92% 까지 분해되었다. 그러나 1/10 희석된 폐수에서는 초기 페놀류 화합물 농도가 2,875 mg/l로 높아 생물학적 처리가 이루어지지 않고 균체가 사멸하였다. 1/40, 1/20 희석된 페수의 생물학적 처리후 잔류 페놀류 화합물을 흡착처리한 결과 최종 처리수에서 페놀류 화합물의 농도는 1 mg/l 이하로 총 페놀제거효율은 99.9%에 달하였다.

• 대한치과보철학회지
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• 제43권4호
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• pp.562-572
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• 2005

Statement of problem : Titanium is widely used as an implant material lot artificial teeth. Also, studies on surface treatment to form a fine passive film on the surface of commercial titanium or its alloys and improving bioactivity with bone have been carried out. However, there is insufficient data about the biocompatibility of the implant materials in the body. Purpose: The purpose of this study was to examine whether the precipitation of apatite on titanium metal is affected by surface modification. Materials and methods: Specimens chemically washed for 2 minute in a 1:1:1.5 (in vol%) mixture of 48% HF 60% $HNO_3$ and distilled water. Specimens were then chemically treated with a solution containing 97% $H_2SO_4$ and 30% $H_2O_2$ at $40^{\circ}C$S for 1 hour, and subsequently heat-treated at $400^{\circ}C$ for 1 hour. All specimens were immersed in the HBSS with pH 7.4 at $36.5^{\circ}C$ for 15 days, and the surface were examined with TF-XRD, SEM, EDX and XPS. Also, commercial purity Ti specimens with and without surface treatment were implanted in the abdominal connective tissue of mice for 4 weeks. Conventional aluminium and stainless steel 316L were also implanted for comparison. Results and conclusions : The results obtained were summarized as follows. 1. An amorphous titania gel layer was formed on the titanium surface after the titanium specimen was treated with a $H_2SO_4$ and $H_2O_2$ solution. The average roughness was $2.175{\mu}m$ after chemical surface treatment. 2. The amorphous titania was subsequently transformed into anatase by heat treatment at $400^{\circ}C$ for 1 hour. 3. The average thickness of the fibrous capsule surrounding the specimens implanted in the connective tissue was $46.98{\mu}m$ in chemically-treated Ti, and 52.20, 168.65 and $100.95{\mu}m$ respectively in commercial pure Ti, aluminum and stainless steel 316L without any treatment.

• 한국수정란이식학회지
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• 제18권2호
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• pp.125-134
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• 2003

본 연구는 사람의 시험관아기 프로그램에서 체외 수정란의 질을 향상시키는 한 방법으로 난포액으로 처리된 정자를 체외 수정에 사용하여 생산된 체외 수정란의 전핵 등급과 발달 능력을 조사하였다. 정상적인 시험관 아기 시술을 시행한 실례 환자를 대상으로 과배란을 유기하여 배란 직전의 난자를 채취하여, 난포액으로 처리된 정자와 체외 수정시킨 후 사람 체외 수정란의 전핵 등급과 체외발달율을 조사하였다. 체외수정을 위한 정자의 처리 방법으로 synthetic serum substitute (SSS)를 15% 첨가한 modified human total fluid (m-hTF) 혹은 난포액에서 정자를 2시간 동안 swimming-up 처리 후 각각 체외수정에 사용한 결과, 수정율은 75.3 및 82.1%를 나타내어 유의적인 차이는 없었으나, 1등급 전핵란은 각각 48.0 및 65.5%를 나타내어 난포액에서 유의적으로 (P<0.05) 높았고, 배양 후 3일째에 수정란의 등급을 조사한 결과, 1등급 체외수정란은 각각 44.9 및 60.5%를 나타내어 난포액에서 유의적으로 (P<0.05) 높았다. 또한 체외수정란을 배양 후 3일째에 수정란의 발달 단계를 조사 한 결과, 5-세포기 단계 이상을 발달하는 비율은 각각 51.0 및 70.5%를 나타내어 난포액에서 유의적으로 (P<0.05) 높았다.