• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1193-1194
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• 2009

• 대한본초학회지
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• 제36권5호
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• pp.59-67
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• 2021

Objectives : Hibiscus (Hibiscus sabdariffa L.) is rich in antioxidants such as flavonoids and anthocyanins and is known to have anti-inflammatory activity and anti-aging function of the skin, but there is no study on its effect on the skin barrier. This study aim to investigate the positive effect on the skin barrier by confirming the effect of water extracts of Hibiscus sabdariffa L. (WEHS) on the tight junction-related gene expression. Methods : The antioxidant efficacy of WEHS was investigated through ABTS and DPPH assays, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium was performed to examine the effect on cell viability. quantitative Reverse transcription polymerase chain reaction and immunoblot analysis were performed to confirm the effect of WEHS on the expression of tight junction-related genes, and immunofluorescence microscopy was used to confirm the movement of Claudin 1 protein into tight junctions. Results : WEHS showed strong antioxidant activity and induced an increase in both mRNA and protein expression levels of Claudin 1 among tight junction-related genes. The strong localization of Claudine 1 protein increased by WEHS to the tight junction was confirmed by immunofluorescence microscopy. Conclusions : Hibiscus was confirmed through this study to show antioxidant activity and the function of promoting the expression of the tight junction Claudin 1 gene, suggesting that Hibiscus can be used as a material for the prevention and treatment of skin moisturizing and atopy, which have an important influence on tight junction.

• 한국정보통신학회논문지
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• 제20권4호
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• pp.793-798
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• 2016

본 연구에서는 1T-DRAM 응용을 위해 Bipolar Junction Transistor 모드 (BJT mode)에서 비대칭 소스/드레인 수직형 나노와이어 소자의 순방향 및 역방향 메모리 윈도우 특성을 분석하였다. 사용된 소자는 드레인 농도가 소스 농도보다 높으며 소스 면적이 드레인 면적보다 큰 사다리꼴의 수직형 gate-all-around (GAA) MOSFET 이다. BJT모드의 순방향 및 역방향 이력곡선 특성으로부터 순방향의 메모리 윈도우는 1.08V이고 역방향의 메모리 윈도우는 0.16V이었다. 또 래치-업 포인트는 순방향이 역방향보다 0.34V 큰 것을 알 수 있었다. 측정 결과를 검증하기 위해 소자 시뮬레이션을 수행하였으며 시뮬레이션 결과는 측정 결과와 일치하는 것을 알 수 있었다. 1T-DRAM에서 BJT 모드를 이용하여 쓰기 동작을 할 때는 드레인 농도가 높은 것이 바람직함을 알 수 있었다.

• 설비공학논문집
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• 제18권1호
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• pp.31-37
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• 2006

The present study has been experimentally investigated the effect of geometric and operating parameters on the two-phase flow distribution of refrigerants in a horizontal T-junction. The operating parameters were the kind of refrigerants (R-22, R- l34a, and R-410A), saturated temperature, and the inlet mass flux and quality. The geometric parameters were the tube diameter and the tube diameter ratio. The measured data of refrigerants were compared with the values predicted using the models developed by several researchers for air/water or steani/water two-phase flow. Among the operating parameters, the inlet Quality was the most sensitive to the mass flow rate ratio. Between the geometric parameters, the tube diameter ratio was more sensitive than tube diameter.

• Journal of electromagnetic engineering and science
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• 제4권4호
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• pp.150-155
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• 2004

Universal design equations are presented for the H-plane T-junction power divider with a circular conducting post in a rectangular waveguide. For a given operating frequency and power split ratio, the post offset from the T-junction center line, the distance between the post and the waveguide wall, and the post diameter can be adjusted to obtain a minimum reflection at the input waveguide. Optimum values of the post offset are given in terms of the normalized frequency and the power split ratio. Corresponding values of the post diameter and the distance of the post from the waveguide wall are given in terms of the normalized frequency and the post offset.

• 한국가시화정보학회지
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• 제1권1호
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• pp.75-81
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• 2003

A custom micro-PIV optics assembly has been used to measure the flow fold inside a T-junction of a microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620 nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of 2.0, 4.0, 6.0 mL/hr. The micro-channels are fabricated with PDMS with a silicon mold, then O$_{2}$ -ion bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results include PIV data with vector-to-vector distances of 2 $\mu$m with 32 pixel-square interrogation windows at 50$\%$ overlap.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2658-2663
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• 2008

In the present study, we designed a microfluidic flatform that generates monodisperse droplets with diameters ranging from hundreds of nanometers to several micrometers. To generate fine droplets, T-junction and flow-focusing geometry are integrated into the microfluidic channel. Relatively large aqueous droplets are generated at the upstream T-junction and transported toward the flow-focusing geometry, where each droplet is broken up into the targeted size by the action of viscous stresses. Because the droplet prior to rupture blocks the straight channel that leads to the flow-focusing geometry, it moves very slowly by the pressure difference applied between the advancing and receding regions of the moving droplet. This configuration enables very low flow rate of inner fluid and higher flow rate ratio between inner and outer fluids at the flow-focusing region. It is shown that the present microfluidic device can generate droplets with diameters about 1 micrometer size and standard deviation less than 3%.

• 한국화재소방학회논문지
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• 제33권1호
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• pp.105-112
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• 2019

본 연구에서는 T자형의 복도 연결 공간에서 비상 방송음이 명료하고 고르게 전달되는지를 건축음향 시뮬레이션을 이용하여 알아보았다. 복도 공간의 흡음성능 변화, 비상 방송용 확성기의 설치 위치와 간격을 변화시켜 보았으며 변화에 따른 음압 레벨 분포, 음성 전달 지수(STI, RASTI) 분포를 비교하였다. 시뮬레이션 결과 명료한 음성 전달을 위해서는 비상 방송용 확성기를 T자형 복도 연결부의 중심에서 약 10 m를 이격시켜 설치하는 것이 좋은 것으로 나타났다. NFSC의 25 m 설치 간격을 좁히는 경우 더욱 명료하고 충분한 음량을 갖는 비상 방송음이 고르게 전달될 수 있는 것으로 나타났다.

• 대한통합의학회지
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• 제9권2호
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• pp.83-92
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• 2021

Purpose : Keratinocytes are the main cellular components involved in wound healing during re-epithelization and inflammation. Dysfunction of tight junction (TJ) adhesions is a major feature in the pathogenesis of various diseases. The purpose of this study was to identify the various effects of a Sparassis crispa water extract (SC) on HaCaT cells and to investigate whether these effects might be applicable to human skin. Methods : We investigated the effectiveness of SC on cell HaCaT viability using MTS. The antioxidant effect of SC was analyzed by comparing the effectiveness of ABTS to that of the well-known antioxidant resveratrol. Reverse-transcription quantitative polymerase chain reaction (qRT-PCR) is the most widely applied method Quantitative RT-PCR analysis has shown that SC in HaCaT cells affects mRNA expression of tight-junction genes associated with skin moisturization. In addition, Wound healing is one of the most complex processes in the human body. It involves the spatial and temporal synchronization of a variety of cell types with distinct roles in the phases of hemostasis, inflammation, growth, re-epithelialization, and remodeling. wound healing analysis demonstrated altered cell migration in SC-treated HaCaT cells. Results : MTS analysis in HaCaT cells was found to be more cytotoxic in SC at a concentration of 0.5 mg/㎖. Compared to 100 µM resveratrol, 4 mg/㎖ SC exhibited similar or superior antioxidant effects. SC treatment in HaCaT cells reduced levels of claudin 1, claudin 3, claudin 4, claudin 6, claudin 7, claudin 8, ZO-1, ZO-2, JAM-A, occludin, and Tricellulin mRNA expression by about 1.13 times. Wound healing analysis demonstrated altered cell migration in SC-treated HaCaT cells and HaCaT cell migration was also reduced to 73.2 % by SC treatment. Conclusion : SC, which acts as an antioxidant, reduces oxidative stress and prevents aging of the skin. Further research is needed to address the effects of SC on human skin given the observed alteration of mRNA expression of tight-junction genes and the decreased the cell migration of HaCaT cells.

• 한국인터넷방송통신학회논문지
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• 제13권2호
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• pp.33-39
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• 2013

본 논문에서는 시스템에서 사용 가능한 자계면 T-접합 구조를 갖는 X/Ku 밴드 도파고나 다이플렉서를 설계하고 특성을 확인하였다. 본 논문에서는 시스템에서 사용 가능한 자계면 T-접합 구조를 갖는 X/Ku 밴드 도파관 다이플렉서를 설계하고 특성을 확인하였다. 설계된 다이플렉서는 X 밴드(7.25 ~ 8.4 GHz) 주파수와 Ku 밴드(12.25 ~ 14.5 GHz) 주파수를 분리시키도록 설계하였다. 일반적인 다이플렉서는 저역통과필터와 고역통과필터, 그리고 도파관 접합부로 결합된다. 그러나 본 논문에서는 저역통과필터를 사용하지 않고 고역통과필터 자계면에 임피던스를 매칭시켜 도파관을 접합함으로써 다이플렉서 구조를 간소화 하였다. 또한, 직교모드 변환기 특성을 갖는 다이플렉서를 설계하여 수직 및 수평편파를 사용할 수 있게 하였다. 본 논문에서 설계한 다이플렉서는 이중대역 및 이중편파를 만족하는 것으로 위성통신용 안테나 피드 시스템에 사용 가능하리라 생각된다.