• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.80-83
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• 2000

In this work we deposited Pentacene thin film by OMBD at the various substrate temperatures, deposition rate and the various annealing temperatures for the fabrication of organic TFT and investigated the electrical and film surface characteristics such as sheet resistance, contact resistance and conductance Film thickness were measured by $\alpha$-step and the sheet resistance, contact resistance and conductance were extracted from the relation between the distance of the contacts and the resistance. During the film deposition the substrate temperature was held at 3$0^{\circ}C$, 4$0^{\circ}C$, 5$0^{\circ}C$, 6$0^{\circ}C$, 8$0^{\circ}C$ and 10$0^{\circ}C$, respectively. After the film deposition, Au contact was deposited by thermal evaporation. For the effect of annealing, the thin film was annealed in the nitrogen environment at 10$0^{\circ}C$ and 14$0^{\circ}C$ for 10 seconds, respectively. Film surface characteristics at the vatious substrate temperatures were measured by AFM. The crystallization of thin film was improved as the substrate temperatures were increased and the maximum gram size was 4${\mu}{\textrm}{m}$. The conductivity of thin film was found to be 7.40 $\times$10$^{-7}$ ~ 7.78$\times$10$^{-6}$ S/cm and the minimum contact resistance was 2.5324 ㏁.

• Journal of Life Science
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• v.30 no.1
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• pp.77-81
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• 2020

The aim of this study was to overcome some of the limiting factors that the maxi cryopreservation straw of 5 ml presents in processing boar semen. Cryopreservation of semen samples was conducted in 0.5 ml and 5.0 ml straws at two freezing rates: -140℃ in 8 minutes and 30 seconds (FR-1) and -140℃ in 14 minutes (FR-2). The straws were then thawed and the semen parameters were compared by Computer Assisted Sperm Analysis, and sperm morphology and acrosome status were examined by Coomassie blue staining. The effects of different thawing temperatures and durations were also compared, namely 37℃ for 115 sec, 50℃ for 45 sec, or 70℃ for 25 sec. In general, the FR-1 group showed higher (p<0.05) sperm viability and motility than the FR-2 group in the 5.0 ml straws. Compared to other ranges, thawing at 50℃ for 45 sec showed the highest sperm viability and motility (68.4±3.6% and 69.5±2.2%, p<0.05), suggesting that thawing temperature should be adjusted concurrently with freezing rate. Sperm morphology and acrosome integrity did not significantly differ among the groups (p>0.05). The data obtained in this study suggest that improving the freezing-thawing protocol for one artificial insemination dose straws (5.0 ml) retains the sperm's parameters from 0.5 ml cryopreservation, and is more convenient to handle, which could result in enhanced reproductive performance.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.87-94
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• 2010

Objective: Many studies have carried out research on comparisons between laser etching and conventional etching systems to investigate methods of reinforcing shear bond strength. The purposes of this study were to assess the efficiency of bonding with erbium, chromium doped: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching combined with the conventional etching technique. Methods: Sixty-four sound premolars, extracted for orthodontic purposes, were randomly divided into 4 groups and treated in the following manner. First group, conventional etching of 37% phosphoric acid for 15 seconds (control); second group, 1.5 W laser etching for 10 seconds followed by conventional etching; third group, conventional etching followed by 1.5 W laser etching; fourth group, 1.5 W laser etching for 15 seconds only. We assessed the shear bond strength, the surface characteristics, and the adhesive remnant index scores between all groups. Results: Experimental groups showed higher shear bond strength than the control group. But no statistically significant differences were found between the second and third groups. Adhesive remnant scores were compared with the Kruskal-Wallis test, and no statistically significant differences were found between all groups. Conclusions: To obtain maximum shear bonding strength, a combined technique of Er,Cr:YSGG and 37% phosphoric acid is useful even though it may be inconvenient.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.3 s.32
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• pp.23-30
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• 2004

Interfacial reaction of Pb-free $Sn0.7wt{\%}Cu$ and $Sn3.8wt{\%}Ag0.7wt{\%}Cu$ solders and Pt during aging has been investigated. After the $Sn3.8wt{\%}Ag0.7wt{\%}Cu/Pt$ specimens were reflowed at $250^{\circ}C$ for 30s and the $Sn0.7wt{\%}Cu/Pt$ specimens were reflowed at $260^{\circ}C$, the specimens were aged at $125^{\circ}C,\;150^{\circ}C$ and $170^{\circ}C$ for 25-121 hours. The intermetallic thitkness and morphology change during aging were characterized using SEM, EDS and XRD. $PtSn_4$ and $PtSn_2$ were observed in the solder/pt interface and the intermetallic formation was governed by diffusion. The activation energy of intermetallic formation was 145.3 kJ/mol for$Sn3.8wt{\%}Ag0.7wt{\%}Cu/Pt$ specimens for $Sn0.7wt{\%}Cu/Pt$ specimens from the measurement of the intermetallic thickness with aging temperature and time.

• Culinary science and hospitality research
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• v.18 no.1
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• pp.40-53
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• 2012

The quality changes of vegetables including cucumbers, young pumpkins, carrots, radishes, onions by different cooking methods in $90^{\circ}C$ water, 0.5% NaCl solution, 1.0% NaCl solution and $400^{\circ}C$ superheated steam were investigated. The changes in pH of cooked vegetables were increased. Hunter color system values for L(lightness), a(redness) and b(yellowness) of the vegetables cooked in $400^{\circ}C$ supetbeated steam for 30 seconds were less compared with those in $90^{\circ}C$ water, 0.5% NaCl solution and 1.0% NaCl solution. The microbial growth was inhibited very effectively when the vegetables cooked in $400^{\circ}C$ superheated steam for 30 seconds. After cooked in $90^{\circ}C$ water, 0.5% NaCl solution, 1.0% NaCl solution, $400^{\circ}C$ superheated steam, vitamin C content decreased by different ratio depending on cooking methods and vegetable varieties. Based on the results of the quality changes of cooked vegetables, the superheated steam cooking method showed a positive effect on sterilization and maintaining pH, color, hardness of vegetable tissues, vitamin C content. The data obtained from this study could be utilized as basic information for the optimum conditions of superheated steam cooking to develope HMR(Home Meal Replacement).

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.145-149
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• 1997

Lipoxygenase activity from brown rice varieties (Tongjinbyeo, Kumohbyeo and Kanchukbyeo) was investigated using spectrophotometric method. In all three varieties, there was an increase in the enzyme activity with the reaction time. Enzyme activity was tested at different concentration of the substrate. The $V_{max}\;and\;K_m$ values of Tongjin, Kumoh and Kanchukbyeo were 57.89, 19.85 and 31.38 units/mg protein and 0.054, 0.045 and 0.035 mM. The study of lipoxygenase activity at different pH levels showed that all the varieties had maximal activities around $pH\;7.0{\sim}7.6$. The enzyme activity and specific activity on milled fractions of different brown rice varieties, fraction II was superior to the other fractions and fraction IV was inferior to the other fractions. As the result of microwave heating for 0, 30, 60 and 90 sec, the enzyme activity and specific activity of all the varieties were decreased by the elapse of heating time.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.806-813
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• 2000

Attempts were made to evaluate possibilities of adding water soluble chitosan to milk for improving functionality of milk, and physico-chemical and sensory properties of chitosan added milk were studied. pH and acidity of milk with ethyl alcohol washed chitosan were close to those of control. Color and consistency of chitosan added milk were better with chitosan of lower molecular weight than with high molecular weight. Chitosan of high molecular weight resulted in increased consistency and browning of milk. Milk with less than 1.0% chitosan could be sterilized at $73^{\circ}C$ for 15 sec. with minimum protein coagulation and increase of consistency. Low molecular weight chitosan$(MW\;0.2{\sim}3\;kDa)$ accelerated the growth of Bifidobacterium bifidum, showing 10 times more cell population after 32 hrs incubation. Sensory tests showed that adding chitosan to the regular city milk resulted in significant difference in color and chemical off-flavor(p<0.05). When chitosan was added to coffee milk, there was no significant difference in sensory quality from control. The storage test showed that pH, acidity, consistency and color of coffee milk with 0.5% chitosan did not change markedly during 30 days storage at 0 and $5^{\circ}C$, but changed rapidly after 16days storage at $10^{\circ}C$. Bacterial counts increased when storage temperature was high, and the growth of bacteria was delayed in coffee milk with chitosan.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.74-74
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• 2001

난자 동결방법의 선별은 보다 효과적인 난자은행의 개발에 필수 불가결한 중요한 요소이다. 이전의 연구에서 마우스의 난자를 ethylene glycol과 electron microscope grid를 이용한 유리화 동결법으로 동결 융해한 결과 기존의 slow freezing 방법에서보다 높은 생존율과 배발달율이 나타남을 관찰하였다. 그러나 동결융해후의 난자는 방추사와 염색체의 이상성이 대조군에 비해 높은 빈도로 나타나 융해후의 배발달율을 감소시키는 것으로 보고되었다. 이에 본 연구에서는 유리화동결법동안 항동해제에 Cytoskeleton system을 안정화시키는 cytoskeleton stabilizer인 taxol을 첨가시킨후 동결시켰을때 생존율과 발달율을 개선시킬 수 있는지 알아보고자 본 실험을 시행하였다. ICR mouse의 성숙란을 채취하여 연구목적에 따라 taxol을 첨가시키지 않은 대조군과 첨가시킨 실험군으로 분류하였다. 동결방법은 난자를 1.5 M ethylene glycol (EG)에 2분 30초간 노출시킨후 5.5 M EG와 1 M sucrose가 첨가된 동결액에 20초간 노출시킨 후 Grid에 난자를 부착시킨후 직접 액체질소에 침지하여 동결하였다. 동결후 난자는 5단계로 융해를 실시한 후 정자와 체외수정을 시킨 후 수정된 난자는 modified P1 배약액에 124 h까지 발달율을 관찰하였고, 배양 후 발달된 배반포는 대조군과 실험군, 각각 4마리의 발정동기화된 recipient에 이식을 시행하였다. 배발달율은 대조군에 비해 실험군에서 4세포기 (48 vs. 84.4%), 8세포기 (34% vs. 70.6%), 상실배 (26% vs. 58.6%) 그리고 배반포 발달율은 (24% vs. 58.6%)로 높게 관찰되었다. 배아이식후 대조군과 실험군에서 각각 2 마리가 임신이되어 정상적인 산자를 분만하였다. 따라서 항동해제에 taxol의 첨가는 동결 융해후의 난자의 배발달율을 증진시킬 수 있었다..8%로 나타나 난할율 및 배반포 발생율에 있어서 융합조건에 따라 큰 차이는 없었으나 1.9㎸/cm, 30$\mu\textrm{s}$ 2회의 조건이 다른 조건들에 비하여 유의적으로 낮았다. 따라서, 체세포와 수핵란 세포질간의 융합율과 배반포 발생에 미치는 영향은 전압보다는 시간에 더 크게 받음을 알 수 있었으며, 이와 같은 결과에서 융합시 시간을 오래 주는 것보다 전압을 높이는 것이 수핵난자의 세포질에 상해를 줄이고 이후 배반포 발생에 유리할 것으로 사료되었다.면에서도 더욱 더 활발할 것으로 기대된다. 배란후 72시간째에 초음파진단기를 이용하여 난소의 난포발달을 조사한 결과 , 대조구와 bFF처리구에 비해 AI처리구에서 발달난포가 유의적으로 많은 것을 확인하였다. 이상과 같은 결과로, Anti-inhibin serum은 한우 자체에서 분비하는 Inhibin을 특이하게 억제하여 Inhibin에 의해 억제되는 FSH분비가 촉진됨으로써 난포발달과 estrogen의 농도가 촉진되는 것으로 사료되어 anti-inhibin serum이 한우의 과배란유기 효과가 있는 것으로 사료된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가 있음을 시사한다.se that were all low in two aspects, named "the Nonsignificant group". And the issues were high risk perception in general setting and

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.75-75
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• 2001

유리화 동결법은 동결중 ice crystal의 형성이 이루어지지 않으므로 난자의 동결보존을 위한 유용한 동결방법이다. 이전의 연구에서 마우스의 난자를 ethylene glycol과 electron microscope grid를 이용한 유리화 동결법으로 동결 융해한 결과 기존의 slow freezing 방법에서보다 높은 생존율과 배발달율이 나타남을 관찰하였다. 그러나 동물과 인간 난자를 이용한 연구를 통하여 난자의 경우 동결 융해후 염색체에 부착되어 있는 미세소관인 방추사가 온도의 변화에 매우 민감하여 염색체 이상성이 증가되는 것이 보고되었다. 이에 본 연구에서는 성숙난자를 유리화동결법에 의해 동결 융해후 난자의 염색체와 방추사의 이상성이 증가되는지 알아보고자 본 실험을 수행하였다. ICR mouse의 성숙란을 채취하여 연구목적에 따라 fresh한 대조군과 동결음해 시킨 실험군으로 분류하였다. 동결방법은 난자를 1.5 M ethylene glycol (EG)에 2분 30초간 노출 시킨후 5.5 M EG와 1M sucrose가 첨가된 동결액에 20초간 노출시킨 후 Grid에 난자를 부착시킨 후 직접 액체질소에 침지하여 동결하였다. 동결후 난자는 5단계로 융해를 실시한 후 생존된 난자는 tubulin 항체를 이용한 immunostaining 방법으로 방추사의 이상성을 관찰하였고, 염색체는 난자를 고정 후 10% Giemza로 염색 후 염색체의 수적인 이상성을 관찰하였다. 염색체 분석결과 염색체 이상 빈도는 대조군의 경우 19.6%, 동결융해군은 32.8%로 관찰되었다. 또 방추사의 이상빈도는 대조군의 경우 20.2%, 동결 융해군은 32.3%로 관찰되어 동결 융해후의 난자에서 염색체와 방추사의 이상 빈도가 증가됨이 관찰되었다.찰되었다. 배아이식후 대조군과 실험군에서 각각 2 마리가 임신이되어 정상적인 산자를 분만하였다. 따라서 항동해제에 taxol의 첨가는 동결 융해후의 난자의 배발달율을 증진시킬 수 있었다..8%로 나타나 난할율 및 배반포 발생율에 있어서 융합조건에 따라 큰 차이는 없었으나 1.9㎸/cm, 30$\mu\textrm{s}$ 2회의 조건이 다른 조건들에 비하여 유의적으로 낮았다. 따라서, 체세포와 수핵란 세포질간의 융합율과 배반포 발생에 미치는 영향은 전압보다는 시간에 더 크게 받음을 알 수 있었으며, 이와 같은 결과에서 융합시 시간을 오래 주는 것보다 전압을 높이는 것이 수핵난자의 세포질에 상해를 줄이고 이후 배반포 발생에 유리할 것으로 사료되었다.면에서도 더욱 더 활발할 것으로 기대된다. 배란후 72시간째에 초음파진단기를 이용하여 난소의 난포발달을 조사한 결과 , 대조구와 bFF처리구에 비해 AI처리구에서 발달난포가 유의적으로 많은 것을 확인하였다. 이상과 같은 결과로, Anti-inhibin serum은 한우 자체에서 분비하는 Inhibin을 특이하게 억제하여 Inhibin에 의해 억제되는 FSH분비가 촉진됨으로써 난포발달과 estrogen의 농도가 촉진되는 것으로 사료되어 anti-inhibin serum이 한우의 과배란유기 효과가 있는 것으로 사료된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며

• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.90-97
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• 2008

The purpose of this study was to evaluate the effect of passive or active application of primer and coat times of bond on the shear bond strength when a self-etching primer adhesive (Clearfil SE Bond) was applied to enamel surface. Crowns of sixteen human molars were selected. Buccal and lingual enamels of crowns were partially exposed and slabs of 1.2 mm thick were made. They were divided into one of four equal groups (n = 8). Group 1: passive application of Primer and 1 coat of Bond, Group 2: active application of Primer and 1 coat of Bond, Group 3: passive application of Primer and 2 coats of Bond, Group 4: active application of Primer and 2 coats of Bond. Clearfil AP-X was bonded to enamel suface of each group using Tygon tubes. The bonded specimens were subjected to microshear bond strength (uSBS) testing with a crosshead speed of 1 mm/min. The results of this study were as follows; 1. The uSBS of Group 1 was the lowest among groups and the uSBS of Group 4 was the highest. 2. There was not statistically significant interaction between enamel uSBS by application method of Primer and coat time of Bond (p > 0.05). 3. There was not statistically significant difference between enamel uSBS by passive and active application of Primer (p > 0.05). 4. There was statistically significant difference between enamel uSBS by one- and two-coat of Bond (p < 0.05).