• 한국재료학회지
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• 제12권12호
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• pp.962-966
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• 2002

The $SrBi_2$$Nb_2$$O_{9}$ (SBN) thin films were deposited with $SrNb_2$$O_{6}$ / (SNO) and $Bi_2$$O_3$ targets by co-sputtering method. For the growth of SBN thin films, we adopted the various power ratios of two targets; the power ratios of the SNO target to $Bi_2$$O_3$ target were 100 W : 20 W, 100 W : 25 W, and 100 W : 30 W during sputtering the SBN films. We found that the electrical properties of SBN films were greatly dependent on Bi content in films. The $Bi_2$Pt and $Bi_2$$O_3$ phase as second phases occurred at the films with excess Bi content greater than 2.4, resulting in poor ferroelectric properties. The best growth condition of the SBN films was obtained at the power ratio of 100 W : 25 W for the two targets. At this condition, the crystallinity and electrical properties of the films were improved at even low annealing temperature as $700^{\circ}C$ for 1h in oxygen ambient and the Sr, Bi and Nb component in the SBN films were about 0.9, 2.4, and 1.8 respectively. From the P-E and I-V curves for the specimen, the remnant polarization value ($2P_{r}$) of the SBN films was obtained about 6 $\mu$C/c $m^2$ at 250 kV/cm and the leakage current density of this thin film was $2.45$\times$10^{-7}$ $A/cm^2$ at an applied voltage of 3 V.V.

• 대한전자공학회논문지SD
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• 제38권3호
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• pp.229-235
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• 2001

Si₃N₄/SiO₂/Si₃N₄ 멤브레인에 의해 실리콘 기판으로부터 열차단된 비냉각 초전형 박막 (Ba,Sr)TiO₃ 적외선 검지기를 제작하고, 적외선 검지기의 특성을 논의하였다. 25℃의 공기중에서 쵸핑주파수가 1 ㎐일 때 적외선 검지기는 약 168.8 V/W의 비교적 높은 전압 감응도를 나타내었으나, 매우 작은 신호대잡음비 때문에 약 2.6×10⁴㎝·㎐/sup 1/2//W의 낮은 비검지도를 나타내었다. 또한 출력파형의 쵸핑주파수 및 온도 의존성에 대한 정성적인 해석으로부터 적외선 검지기의 열잡음전압 및 열시정수가 모두 상당히 크다는 것을 알 수 있었다.

• Journal of Nutrition and Health
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• 제27권1호
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• pp.23-45
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• 1994

It has been recently reported that degenerative diseases are increasing rapidly in many other countries as well as in Korea according to expansion of life expectancy, economic development and dietary patterns. The aim of this study was to investigate changes in lipid metabolism with age, to determine which dietary factors affect the serum lipid profiles, and to compare Korean and western diets. With clinically normal participants(made 60, female 63), this study was carried out in three phases : 1) to analyze blood lipid levels with age, 2) to analyze the effects of different dietary intakes on blood lipid levels according to age, and 3) to compare the effects of different food intakes on blood lipids between eastern and western coutries. The results are follows : 1) Mean serum values of triglyceride and cholesterol reached a peak level at the age of 50-60 years, although men has higher levels than women at earlier ages. LDL cholesterol percentage increased sharply after 50 years and continued to 70 years. 2) Differences of dietary calorie intake including carbohydrate, total fat and animal fat affected serum lipid profiles, such that high intake groups generally showed higher triglyceride and cholesterol values than the lower intake groups. 3) Compared with Americans(45%), Koreans consumed carbodydrates at 65% of their calorie intake. At this carbohydrate level dietary fatty acid P/S and W-6/W-3 ratio were 1.1 and 6, this could make Koreans continue this dietary pattern composed of carbohydrate at 65% of total calorie intake, and P/S ratio of fatty acid at 1 to 2.

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1776-1783
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• 2006

Despite being a rich source of protein (28-34%), karanj (Pongamia glabra) cake is found to be bitter in taste and toxic in nature owing to the presence of flavonoid (karanjin), tannin and trypsin inhibitor, thereby restricting its safe inclusion in poultry rations. Feeding of karanj cake at higher levels (>10%) adversely affected the growth performance of poultry due to the presence of these toxic factors. Therefore, efforts were made to detoxify karanj cake by various physico-chemical methods such as dry heat, water washing, pressure cooking, alkali and acid treatments and microbiological treatment with Sacchraromyces cerevisiae (strain S-49). The level of residual karanjin in raw and variously processed cake was quantified by high performance liquid chromatography and tannin and trypsin inhibitor was quantified by titrametric and colorimetric methods, respectively. The karanjin, tannin and trypsin inhibitor levels in such solvent and expeller pressed karanj cake were 0.132, 3.766 and 6.550 and 0.324, 3.172 and 8.513%, respectively. Pressure-cooking of solvent extracted karanj cake (SKC) substantially reduced the karanjin content at a cake:water ratio of 1:0.5 with 30-minute cooking. Among chemical methods, 1.5% (w/w) NaOH was very effective in reducing the karanjin content. $Ca(OH)_2$ treatment was also equally effective in karanjin reduction, but at a higher concentration of 3.0% (w/w). A similar trend was noticed with respect to treatment of expeller pressed karanj cake (EKC). Pressure cooking of EKC was effective in reducing the karanjin level of the cake. Among chemical methods alkali treatment [2% (w/w) NaOH] substantially reduced the karanjin levels of the cake. Other methods such as water washing, dry heat, HCl, glacial acetic acid, urea-ammoniation, combined acid and alkali, and microbiological treatments marginally reduced the karanjin concentration of SKC and EKC. Treatment of both SKC and EKC with 1.5% and 2.0% NaOH (w/w) was the most effective method in reducing the tannin content. Among the various methods of detoxification, dry heat, pressure cooking and microbiological treatment with Saccharomyces cerevisiae were substantially effective in reducing the trypsin inhibitor activity in both SKC and EKC. Based on reduction in karanjin, in addition to tannin and trypsin inhibitor activity, detoxification of SKC with either 1.5% NaOH or 3% $Ca(OH)_2$, w/w) and with 2% NaOH were more effective. Despite the effectiveness of pressure cooking in reducing the karanjin content, it could not be recommended for detoxification because of the practical difficulties in adopting the technology as well as for economic considerations.

• 한국구조물진단유지관리공학회 논문집
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• 제3권4호
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• pp.163-171
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• 1999

In this study, we executed fundamental experiment to investigate properties of accelerated carbonation with changing chloride content of concrete used sea sand in order to examine durability. So we obtained the results of following properties of mechanics, durability, concrete with sea sand, determined concrete w/C 30%, 40%, 50%, and fine aggregate 40% and changing containing chloride 0, 0.3, 0.6, $0.9kg/m^3$ by the experiment of accelerated neutralization. The results of this study as follows: 1) As result of changing chloride content of concrete used sea sand augmented in stages $0.3kg/m^3$, accelerated carbonation was increased as increment chloride content. The increment depth was decreased as it went long term age. It was shown the chloride content effected increment of carbonation depth in concrete 2) As a result of changing W/C of concrete used sea sand augmented in stages 10% at a time from 30% to 50%, accelerated carbonation depth of concrete was increased as W/C ratio. 3) As the carbonation concrete used sea sand, compressive strength between 8 weeks and accelerated carbonation depth of 1 weeks, 2 weeks, 4 weeks, 8 weeks was inversion proportion.

• 한국가스학회지
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• 제20권6호
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• pp.65-72
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• 2016

천연가스용으로 개조된 가스엔진에서 방출되는 폐열을 활용하기 위한 유기 랭킨사이클 (Organic Rankine Cycle: ORC) 발전시스템을 설계 및 제작하였다. 이 연구에서는 개조된 가스엔진의 폐열을 실험적으로 분석한 데이터를 바탕으로 구성한 ORC 시스템의 컴포넌트를 설계하고 제작하였다. ORC 시스템에는 2개의 판형 열교환기와 5kW급 팽창기, 다단 펌프가 사용되었으며, 전기 히터를 이용하여 ORC 시스템의 열역학적 성능을 분석하였다. 또한, 실제로 가스엔진과 연동하여 작동 특성을 파악하기 위한 실험을 수행하였다. ORC 시스템에 열량을 공급해주는 2대의 가스엔진을 사용하였다. 열원모사실험 결과, 열원온도 $110^{\circ}C$에서 축동력 5.22kW가 발생, 압력비 7.41, 열효율 9.09%가 계산되어졌으며, 엔진연동실험에서는 고온수 온도 $86^{\circ}C$에서 축동력 2kW가 발생, 이 때의 압력비는 3.75, 열효율 6.45%가 계산되었다.

• 한국식품저장유통학회지
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• 제14권5호
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• pp.474-480
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• 2007

홍삼 첨가 액상청국장의 추출공정별 청국장 추출물의 특성 비교 및 청국장의 최적 추출 조건을 설정하고자 하였다. 용매로 물을 사용하여 추출한 홍삼 첨가 액상청국장을 각각 마이크로웨이브 파워별(30, 60, 90, 120 및 150 W), 시간별(1, 5, 9, 13 및 17분)로 추출한 후 생리활성 실험을 수행하였을 때, 수율, 전자공여능, 아질산염 소거능, tyrosinase 저해작용, SOD 유사 활성 등의 생리활성 측정을 통해 추출 최적점을 찾아내었다. 홍삼을 첨가한 액상 청국장의 경우 마이크로웨이브 파워 $0{\sim}85\;W$, 시료에 대한 용매비 $1.4{\sim}2.8\;g/mL$, 추출시간 $6.5{\sim}11$분에서 최적의 조건이 나타났다. 예측결과에 의한 최적조건을 확인하기 위하여 예측된 최적조건 범위 내에서 임의의 조건을 대입하여 이화학적 특성을 예측해본 결과 홍삼을 첨가한 액상 청국장에 대한 임의의 조건으로 시료에 대한 파워 90W, 용매비 2.5 g/mL, 추출 시간 9분을 설정한 후 홍삼을 첨가한 액상 청국장에 대한 각각의 회귀식에 대입하여 얻은 예측된 최적값은 수율 23.04%, 전자공여능 56.33%, 아질산염 소거능 65.62%, tyrosinase 저해작용 4.96%, SOD 유사활성 41.97%로 실험값과 예측값 간의 유의적인 차이가 나타나지 않았다.

• 한국자기학회지
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• 제14권6호
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• pp.228-231
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• 2004

Ta(5 nm)/NiFe(11 nm)/FeMn(16 nm) Ta(5 nm)과 Ta(5 nm)/NiFe(11 run)/FeMn(16 nm)/NiFe(7 nm)/Ta(5 nm) 다층박막구조를 제작하여, Laser의 power, 조사 위치, 자장의 방향에 따라 자기저항(MR)비와 교환결합력(H$_{ex}$) 자기적 특성을 연구하였다. Laser 열처리는 power를 440 mW까지 증가시키면서 FeMn/NiFe 이중박막을 15분 씩 Laser로 조사하여, 200 mW에서부터 음의 자기장에서 자기저항곡선의 피크가 발생하기 시작하였다. 400 mW까지 증가시키면서 양의 자기장에서 자기저항곡선의 MR비와 H$_{ex}$:가 각각 0.9%에서 0.1%로, 87 Oe에서 76 Oe로 감소하였고, 음의 자기장 피크에서는 MR비와 H$_{ex}$가 모두 증가하였다. 또한 NiFe/FeMn/NiFe삼중박막에서도 같은 결과를 얻었다. 300 mA로 laser열처리한 면적을 증가시켰을 때 자기저항곡선이 positive 피크는 감소하고 negative 피크는 증가하였다. 이러한 Laser 열처리효과에 의해 결과적으로 교환결합된 박막구조의 국소적 자화반전을 가능하게 하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권6호
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• pp.602-608
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• 2014

저탄소 친환경 대체 에너지의 한 분야인 수소에너지는 화석연료의 개질 및 물의 전기분해 등 다양한 방법을 통해 얻어진다. 수소를 연료로 사용하는 연료전지인 PEMFC용 1kW급 평판형 수소생산시스템을 자체 개발하였다. FEMFC는 CO에 의한 오염에 민감하므로 공급되는 개질가스 중에 CO 농도는 10ppm 이하로 제거되어야 한다. 본 연구에서는 다양한 실험조건에서 $H_2$ 및 CO의 농도를 측정하여 최적의 운전조건을 확립하였다. 결과적으로 A/F ratio ${\alpha}=1.3$, STR temperature 1023K, S/C ratio 3, and $PrOx1{\cdot}2$ 30cc/min에서 최적임을 확인하였다. 또한 PrOx 2단이 CO 농도를 줄이는데 더욱 효과적임을 알 수 있었다.

• 한국자원식물학회지
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• 제32권3호
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• pp.228-236
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• 2019

This study is conducted to investigate the effects of growth characteristics (GC) and DPPH radical scavenging activity (DRSA) of the heading lettuce 'Fidel' depending on four concentrations of activated mineral groups (AMG: 1.6% active minerals and 0.03% CaO) added to basic nutrient solutions (diluted by 0, 0.05, 0.1, and 0.2%) and on four different light-emitting diodes (LED; B:R:W ratio = 0:1:12, 0:1:9, 0:5:5, and 2:3:5). Both 0.1 and 0.2% AMG showed better GC of lettuce in plant width, plant length, leaf width, leaf length, and the number of leaves than those of other AMG, while leaf thickness and chlorophyll value did not show significant difference among all AMG. Moreover, 0.1 and 0.2% AMG showed heavier shoot fresh weights than those of other AMG. As for the combinations of AMG and LED, B0:R5:W5 showed the best lettuce GC regardless of AMG compared to other AMG and LED combinations. As shown in the above results of LED, although there was a difference in lettuce growth by LED, the differences of lettuce growth by AMG were statistically significant. The DRSA was the highest at 82.8% in B2:R3:W5, followed by B0:R5:W5 at 77.8%. LED showed differences but AMG did not affect DRSA. Therefore, the optimal conditions in plant factory for GC and DRSA of the lettuce were 0.1% AMG and B0:R5:W5.