• 반도체디스플레이기술학회지
• /
• 제22권4호
• /
• pp.19-25
• /
• 2023

With an attempt to investigate the correlation between the internal pressure distribution of slit nozzle and the thickness uniformity of slot-coated thin films, we have performed computational fluid dynamics (CFD) simulations of slit nozzles and slot coating of high-viscosity (4,800 cPs) polydimethylsiloxane (PDMS) using a gantry slot-die coater. We have calculated the coefficient of variation (CV) to quantify the pressure and velocity distributions inside the slit nozzle and the thickness non-uniformity of slot-coated PDMS films. The pressure distribution inside the cavity and the velocity distribution at the outlet are analyzed by varying the shim thickness and flow rate. We have shown that the cavity pressure uniformity and film thickness uniformity are enhanced by reducing the shim thickness. It is addressed that the CV value of the cavity pressure that can ensure the thickness non-uniformity of less than 5% is equal to and less than 1%, which is achievable with the shim thickness of 150 ㎛. It is also found that as the flow rate increases, the average cavity pressure is increased with the CV value of the pressure unchanged and the maximum coating speed is increased. As the shim thickness is reduced, however, the maximum coating speed and flow rate decrease. The highly uniform PDMS films shows the tensile strain as high as 180%, which can be used as a stretchable substrate.

• 반도체디스플레이기술학회지
• /
• 제22권4호
• /
• pp.32-37
• /
• 2023

For the potential applications in large-area OLED lightings, hydrogen fuel cells, and secondary batteries, we have performed an intermittent coating of high-viscosity polydimethylsiloxane using roll-to-roll slot die coater. During intermittent coating, dead zones inevitably appear where the thickness of PDMS patch films becomes non-uniform, especially at the leading/trailing edge. To reduce it, we have coated the PDMS patches by varying the process parameters such as the installation angle of the slot die head, coating speed, and patch interval. It is observed that the PDMS solution flows down and thus the thickness profile is non-uniform for horizonal intermittent coating, whereas the PDMS solution remaining on the head lip causes an increase in the PDMS thickness at the leading/trailing edges for vertical intermittent coating when the coating velocity is low. As the coating speed increases, however, the dead zone is shown to be reduced. It is addressed that the overall dead zone (the dead zone at the leading edge + the dead zone at the trailing edge) is smaller with horizontal intermittent coating than with vertical intermittent coating.

• 반도체디스플레이기술학회지
• /
• 제22권3호
• /
• pp.28-35
• /
• 2023

Moiré patterns emerge due to the interference between the non-emission area of the LED screen and the grid line in an image sensor of a video recording device when taking a video in the presence of the LED screen. To reduce the moiré intensity, we have fabricated an anti-moiré filter using hollow glass microspheres (HGMs) by slot-die coating. The LED screen has a large non-emission area because of a large pitch (distance between LED chips), causing more severe moiré phenomenon, compared with a display panel having a very narrow black matrix (BM). It is shown that HGMs diffuse light in such a way that the periodicity of the screen is broken and thus the moiré intensity weakens. To quantitatively analyze its moiré suppression capability, we have calculated the spatial frequencies of the moiré fringes using fast Fourier transform. It is addressed that the moiré phenomenon is suppressed and thus the amplitude of each discrete spatial frequency term is reduced as the HGM concentration is increased. Using the filter with the HGM concentration of 9 wt%, the moiré fringes appeared depending sensitively on the distance between the LED screen and the camera are almost completely removed and the visibility of a nature image is enhanced at a sacrifice of luminance.

• 대한약리학회지
• /
• 제31권3호
• /
• pp.365-375
• /
• 1995

Anemia-inducing strain of Friend virus (FVA)는 적혈구 progenitor cell의 증식을 촉진하는 생쥐 retrovirus의 일종이다. FVA에 감염된 생쥐는 생성이 촉진된 progenitor cell이 분화되지 못하고 비장내에 축적되므로서 비장비대를 초래한다. 이에 본 실험에서는 FVA에 감염된 생쥐의 비장비대를 지표로 사용하여 2',3'-dideoxycytidine (ddC) 및 $interferon-{\alpha}-A\;(rIFN-{\alpha}-A)$의 항retrovirus효과를 측정하였다. 매일 ddC (100 mg/kg) 및 $rIFN-{\alpha}-A$ (10 KU/mouse)를 각각 단독 또는 병용하여 18일간 복강내 투여시 비장의 비대가 각각 15.1%, 52.7%, 61.6% 억제되었다. 또 다른 실험군으로 ddC를 식수중에 용해하여 (0.1 mg/ml) 경구로 18일간 투여시, 그리고 ddC의 경구투여와 병용하여 $rIFN-{\alpha}-A$을 위와 마찬가지 용량으로 복강내 투여시, 비장비대를 각각 38.4% 및 83.2% 억제하였다. 이 결과는 ddC의 투여시 복강내 주사보다는 경구투여가 더 유효하며, ddC와 $rIFN-{\alpha}-A$는 병용투여시 상가적인 효과가 있음을 제시한다. ddC 투여시 progenitor cell의 특성상 변화를 검토하기 위해, $Ca^{++}$ uptake $[^3H]cyclohexyladenosine$ (CHA) binding 실험을 실시하였다. CHA bindng 실험결과 성숙된 적혈구에서는 저친화성의 결합부위 하나뿐인데 반해, progenitor cell에서는 고친화성과 저친화성의 두가지 결합부위를 나타내었다. $Ca^{++}$ uptake 측정결과 성숙된 적혈구에 비해 대조군의 정상적인progenitor cell은 약 20배 증가를 나타내었으며, ddC를 연속투여한 군에서도 유사한 결과를나타내었다. 이때 CHA에 의한 $Ca^{++}$ uptake의 억제효과를 측정한 바, ddC 100 mg/kg 투여군의 경우 76%로 대조군의 86% 보다 억제효과가 크게 나타났으며, 이들 모두는 adenosine 길항약인 theophylline의 전처치시 대조군과 유사하게 회복되었다.

• 대한지역사회영양학회지
• /
• 제4권2호
• /
• pp.175-185
• /
• 1999

This study was conducted among the university students to investigate the effects of working in an daytime and studying in an evening class on dietary behaviors and nutrient intakes. A 24-hour recall method was used along with food frequency questionnaires. The subjects were composed of three groups : 172 were in the daytime calss regular student group(RS), 178 were evening class students without a job(ESWOJ), and 140 were evening class students with a job(ESWJ). An average age of the ESWJ was 31 years old, which was 9 years older than the RS and 7 years older than the ESWOJ. The types of the residence were significantly different among the groups ; were seif-boarding 74% of the ESWJ stayed at home while 47% of the RS were self-boarding and 61% of the ESWOJ. The survey shows that while a great majority of the RS and ESWOJ has breakfast and supper at home, about 10% and 17% of the ESWJ ate breakfast and supper, respectively, at the cafeteria in their work place. The most frequently skipped meal was the breakfast in all groups. Approximately 9% of the ESWJ tended to skip the breakfast, while 27% of the RS and 33% of the ESWOJ did. It turns out that the mose common reason why ESWJ skipped meals was due to a lack of time. About 71% of the ESWJ ate out more than once a week compared to 57% and 62% of the RS and ESWOJ, respectively. Approximately 30% of the ESWJ ate out more than once a week compared to 57% and 62% of the RS and ESWOJ, respectively. Approximately 30% of the ESWJ spent less than 10 minutes at meal time, showing a hurried eating habit. The results show that the ESWJ tended to eat a variety of food s and eat less instant foods, but drink coffee more often compared to the other two groups. The results also show that in all groups, the intakes of energy, Ca, and vitamin A were lower than the Korean Recommended Daily Allowances(RDA). In addition to these nutrients, protein, vitamin B1, vitamin $B_2$, and niacin were also lower than the RDA in all make students, and Fe was lower than the RDA in all female students. Among the deficient nutrients, vitamin A showed the lowest % RDA : 48% in the male and 64% in the female students. Among the deficient nutrients, vitamin A showed the lowest % RDA ; 48% in the male and 64% in the female students. The intakes of Ca, Fe, and niacin in the ESWJ were significantly greater than those in the RS and ESWOJ groups, and the vitamin C intake in the ESWJ was greater than that in the ESWOJ(p<0.01). In conclusion, university students in all three groups have a serious imbalance in the nutrient intakes, and the evening class students with a daytime job have unhealthy dietary behaviors in the light of high frequency of eating out and heavy coffee drinking, a rushed eating pattern, and therefore showing a strong need of proper nutritional education for them.

• 사상체질의학회지
• /
• 제19권3호
• /
• pp.126-143
• /
• 2007

1. Objectives The purpose of this study is to find out the grade of practical use, the important element and the significant characteristics of Sasangin' s face, voice, skin and pulse diagnostic impression, in Sasang constitutional clinical diagnosis. 2. Methods We analysed the survey data about Sasangin' s face, voice, skin and pulse diagnostic impression, drawn up by specialist in Sasang constitutional medicine. 3. Results and Conclusions (1) In the application degree of face feature, the case which it was applied with 20-40% and 40-60% were 16 people(43.2%) respectively. In voice, the case applied with 0-20% was 19 people(51.4%), in skin, 0-20% and 20-40% were 14 people(37.8%) respectively and in pulse diagnosis, 0-20% were 25 people(73.0%). (2) In constitutional diagnosis, the important element of face were 'frontal whole shape', 'whole impression' and 'size and shape of eye, ear, mose and mouth', the important element of voice 'speed of speech', 'purity and impurity' and 'pitch', the important element of skin 'thickness', 'feel of touch' and 'size of skin pores' and the important element of pulse diagnosis 'speed of pulse', 'sinking and floating' and 'weakness and firmness'. (3) The important face characteristics of Taeyangin were 'bright eye', 'broad forehead' and 'strong impression', Soyangin 'protruding forehead', 'thin and small lips', 'narrowing and sharp chin', Taeumin 'thick lips', 'flat face', 'large eye, nose, ear and mouth' and Soeumin 'long and slender face', 'downward slanting eyes' and 'small eye, nose, ear and mouth', The important voice characteristics of Taeyangin were 'loud' and 'clear', Soyangin 'rapid' and 'high-pitched tone', Taeumin 'chick', 'slow' and 'low-pitched tone' and Soeumin 'small and feeble' and 'slow'. The important skin characteristics of Taeyangin were 'thin' and 'white', Soyangin 'thin', 'smooth' and 'elastic', Taeumin 'thick', 'large skin-pore', 'coarse' and Soeumin 'soft', 'thin' and 'subtle skin-pore'. The important pulse characteristics of Taeyangin were 'rapid' and 'large', Soyangin 'rapid' and 'floating', Taeumin 'tense', 'long' and 'solid' and Soeumin 'fine', 'weak' and 'slow'.