• 신재생에너지
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• 제4권2호
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• pp.68-73
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• 2008

It is very important that constitution of good hetero-junction interface with a high quality amorphous silicon thin films on very cleaned c-Si wafer for making high efficiency hetero-junction solar cells. For achieving the high efficiency solar cells, the inspection and management of c-Si wafer surface conditions are essential subjects. In this experiment, we analyzed the c-Si wafer surface very sensitively using Spectroscopic Ellipsometer for < ${\varepsilon}2$ > and u-PCD for effective carrier life time, so we accomplished < ${\varepsilon}2$ > value 43.02 at 4.25eV by optimizing the cleaning process which is representative of c-Si wafer surface conditions very well. We carried out that the deposition of high quality hydrogenated silicon amorphous thin films by RF-PECVD systems having high density and low crystallinity which are results of effective medium approximation modeling and fitting using spectroscopic ellipsometer. We reached the cell efficiency 12.67% and 14.30% on flat and textured CZ c-Si wafer each under AM1.5G irradiation, adopting the optimized cleaning and deposition conditions that we made. As a result, we confirmed that spectroscopic ellipsometry is very useful analyzing methode for hetero-junction solar cells which need to very thin and high quality multi layer structure.

• Journal of Ginseng Research
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• 제10권1호
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• pp.94-100
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• 1986

홍미삼을 원료로 홍삼엑기스를 제조할때 추출용매, 온도 및 시간등의 추출조건이 홍삼엑기스의 색상과 관능적 조화미에 미치는 영향을 조사한 결과 홍삼엑기스의 색상은 에탄올의 농도증가에 따라 갈색도는 감소되고 L치 및 b치가 증가되는 반면 a치는 감소되어 황절색계가 주가 되었으며 온도상승에서는 이와 반대로 암적황색계가 주가 되었꼬 추출시간 경과에 따라 갈변반응은 계속 진행되었다. 관능적인 홍삼의 향취는 90~50% 에탄올구에서 좋았고 고미성질은 90~70%구에서 현저하였으나 전체적인 조화미로는 70~30%구가 유의성있게 선호되는 것으로 평가되었고 이들 용매에서는 구간의 차이가 없었다. 온도상승으로도 유의적인 차이가 인정되지 않아 홍삼엑기스의 색상과 관능적인 성질에 영향을 미치는 주요한 인자는 추출용매로서 에탄올의 농도임임을 알수 있었다.

• Journal of Ginseng Research
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• 제10권1호
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• pp.36-44
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• 1986

추출조건이 인삼엑기스의 일반성분 및 사포닌 함량에 미치는 영향을 조사하기 위하여 수삼과 백삼을 시료로 추출용매, 용매농도, 온도등의 조건을 달리하여 조사 비교한 결과 수삼의 경우 $70^{\circ}C$ 및 $100^{\circ}C$구가 다른구에 비하여 가용성물질의 용출량이 5배이상 컸으며 사포닌의 용출율은 $70^{\circ}C$-$H_2O$구가 가장 높았고, $100^{\circ}C$구는 거의 1/2이 감소되었다. 압착에 의한 방법으로 사포닌의 52%가 추출되었고 triol계가 diol계 사포닌보다 더 잘 추출되었다. 전당, 환원당, 조단백 및 총 아미노산의 용출율도 $H_2O$구가 ethanol구보다 높은 값을 나타내었고 회분은 압착구에서 높은 값을 보였다.

• 한국자기학회지
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• 제2권3호
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• pp.228-232
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• 1992

고온초전도체 $Y_1Ba_2Cu_3O_{7-y}$의 grain을 높은 자기장에서 정렬시켜 여러가지 자기적 특성을 조사하였다. Grain이 정렬된 초전도체는 단결정과 같이 Cu-O layer에 수직, 수평 방향에 대해 자기이방성을 가진다. 2~77 K의 온도영역에서 측정한 lower critical field$(H_{c1})$은 온도가 증가하면서 선형적으로 감소하였는데, Cu-O layer에 대하여 외부 자기장이 수직인 경우가 더욱 급격히 감소하였다. 온도변화에 따른 자율화$(4{\pi}\;X)$의 측정으로부터 극저온의 자화율이 -1에 가까운 값을 가진다는 것을 알 수 있었다. 또한 이 자화 곡선을 London의 공식과 two-fluid model을 이용해 최소자승법으로 fitting하여 절대 영도에서 침투깊이$({\lambda}_0)$를 구하였다. 또한 2 K에서 외부 자기장에 따른 자화곡선을 측정하였으며, Bean의 critical state model을 이용한 임계전류밀도$(J_c)$의 계산으로부터 grain내부는 단결정 수준의 높은 $(J_c)$를 가지고 있음을 알 수 있었다.

• 한국컴퓨터산업학회논문지
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• 제9권1호
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• pp.21-28
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• 2008

본 논문에서는 입술 주위 영상만으로 독화를 위한 에지 파라미터를 추출하였고, 한국어 5모음 'ㅏ/ㅔ/ㅣ/ㅗ/ㅜ'를 인식하는데 효과적임을 보였다. 발화하는 입주위의 이미지를 $5{\times}5$로 나누고, 각 영역에 소벨 연산자를 적용하여 디지털 에지 수를 구한 후, 이 값들의 관찰 오차를 정규화를 통하여 수정하고, 정규화 된 값을 파라미터로 사용하였다. 파라미터의 견인성을 확인하기 위하여, 자동 독화 시스템을 구축하였다. 인식 실험에 정상인 50명이 동원되었고, 10명의 이미지로 분석하고, 다른 40명의 이미지로 인식 실험을 하였다. 500개의 데이터를 분석하고, 이 분석을 바탕으로 신경망 시스템을 구축하였으며, 400개의 데이터로 인식 실험하였다. 신경망 시스템의 최고 인식 결과는 91.1%였다.

• Journal of Oral Medicine and Pain
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• 제18권2호
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• pp.71-79
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• 1993

Many types of occlusal splints are used for treatment of craniomandibular disorders. Most widely used splint among them is flat-type centric relation splint. Insertion of splint into the mouth may cause increasing of vertical dimension, masticatory muscle realignment and rearrangement of maxillo-mandibular relationship, so as a result of splint treatment, occlusal relation may vary whether you like it or not. From this point of view, occlusal state of patient shold be frequently monitored to prevent undesired or harmful effect during occlusal splint therapy. The purpose of this study was to investigate the effect of occlusal splint, especially centric relation splint, on the occlusal contact state after 3 months treatment. 32 patients with craniomandibular disorders who had unilateral symptoms participated in this study. To observe and record occlusal contact state, the author used T-Scan system (Tekscan Co. U.S.A.) at both pretreatment and posttreatment. The recorded date were analyzed with regard to contact number, contact force and contact time, change of anterior tooth contact and coincidence of first contact point with affected side were observed, too. Aan last, the subjects were divided into 2 groups and compared, according to average value of VAS index, with respect to joint pain, sound and limitation of movement, respectively. The collected date were statistically processed with SPSS and the result as follows : 1. Total occlusal contact number and force were not changed by occlusal splint therapy but total occlusal contact time decreased slightly. 2. There was a tendency of increasing number of subjects with anterior tooth contact after treatment and change of first contact point side were observed in as many as 40.6% of subjects. 3. There were no difference between higher and lower group of VAS index, and between pretreatment and posttreatment in each group, either.

• 응용통계연구
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• 제22권2호
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• pp.261-270
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• 2009

주식 수익률, 환율 등과 같은 금융 자료를 이해하는데 있어서 최근의 국제 금융위기를 통해 더욱 중요해진 이슈는 바로 변동성(volatility)이다. 변동성(조건부 이분산성)에 대한 모형은 Engle (1982)의 ARCH 모형과 Bollerslev (1986)의 GARCH 모형을 시작으로 수만은 연구가 이루어졌으며 특히 금융 시계열 분석에서는 시계열 자료들 간의 변동성을 함께 모형화 하는 MGARCH(multivariate GARCH) 모형이 널리 이용되고 있다. 추정된 MGARCH 모형들은 그 자체로서 여러 개의 변동성들 간의 시간에 따른 동적인 관계를 설명해주는 데 유용할 뿐만 아니라 추정된 (조건부)상관계수들은 hedge ratio 계산 또는 VaR 계산 등과 같이 금융시장에 대한분석에도 이용되고 있다. 본 논문에서는 국내 14개 최신 주가자료에 대한 MGARCH 분석을 수행하고 연관된 사후검증(back-testing)을 통해 MGARCH 모형들을 평가하고 있으며 사후검증 수치를 얻기 위한 S-PLUS 프로그램을 수록하였다.

• 한국환경과학회지
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• 제22권11호
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• pp.1457-1464
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• 2013

We investigated the optimal conditions for keratinase production by feather-degrading Pseudomonas geniculata H10 using one variable at a time (OVT) method. The optimal medium composition and cultural condition for keratinase production were determined to be glucose 0.15% (w/v), beef extract 0.08% (w/v), $KH_2PO_4$ 0.12% (w/v), $K_2HPO_4$ 0.02% (w/v), NaCl 0.07% (w/v), $MgSO_4{\cdot}7H_2O$ 0.03%, $MgCl_2{\cdot}6H_2O$ 0.04% along with initial pH 10 at 200 rpm and $25^{\circ}C$, respectively. The production yield of keratinase was 31.6 U/ml in an optimal condition, showing 4.6-fold higher than that in basal medium. The strain H10 also showed plant growth promoting activities. This strain had ammonification activity and produced indoleacetic acid (IAA), siderophore and a variety of hydrolytic enzymes such as protease, lipase and chitinase. Therefore, this study showed that P. geniculata H10 could be not only used to upgrade the nutritional value of feather wastes but also useful in situ biodegradation of feather wastes. Moreover, it is also a potential candidate for the development of biofertilizing agent applicable to crop plant soil.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1614-1618
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• 2003

Twenty crossbred (HF${\times}$Tharparkar) dry pregnant cows were divided into four equal groups. They were supplemented with 1,000 I.U. $\alpha$-tocopheryl acetate from 0 (group I), 15 (group II), 30 (group III) and 60 (group IV) days before parturition to 1month of lactation. All the cows were kept under similar feeding and management conditions. Blood plasma samples collected on specific days were analyzed for $\alpha$-tocopherol, retinol, total antioxidant activity (FRAP), immunoglobulin and calcium. Plasma $\alpha$-tocopherol concentration at 30 days prepartum averaged 3.5, 4.1, 4.4 and $3.9{\mu}g/ml$ and decreased by 50.0, 41.4, 34.1 and 33.3 percent on the day of parturition in the four respective groups. After calving, plasma vitamin E started to recover earlier in groups II, III and IV as compared to group I. Mean plasma $\alpha$-tocopherol concentration at 21 days postpartum was significantly higher in groups II, III and IV (2.9, 3.5 and $3.1{\mu}g/ml$) compared to group I ($1.9{\mu}g/ml$) cows. Plasma retinol concentration also showed a substantial decrease in all the groups on the day of calving but recovered to its normal value at 3 weeks postpartum. Plasma total antioxidant activity averaged 901, 895, 859 and $875{\mu}mol/l$ in the four respective groups on 30 days prepartum and decreased on the day of calving in all the groups, but the decrease was less in groups III and IV. Plasma immunoglobulin concentration was higher in group IV, followed by groups III, II and I, respectively, showing better immune status of vitamin E supplemented cows due to less oxidative stress. Supplementation of vitamin E resulted in higher plasma calcium concentration. The data showed that vitamin E supplementation should be started at least 30 days prepartum to reduce oxidative stress in periparturient cows.

• Journal of Korean Dental Science
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• 제11권1호
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• pp.14-20
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• 2018

Purpose: The purpose of this study is to measure and compare the removal torques of different cements applied in attachments of zirconia restorations on titanium (Ti) abutments fitted with retrievable cement-type slot (RCS) on the lingual side for the better retrievablity by use of a slot driver. Materials and Methods: Three types of cements were used in the experiment: two permanent cements in $RelyX^{TM}$ U200 (RU) (3M ESPE) which is a resin cement and $FujiCem^{TM}$ (FC) (GC) which is a resin-modified glass ionomer cement, and a temporary cement in $Freegenol^{TM}$ temporary cement (TC) (GC). Measurements of removal torques were conducted as follows; an attached sample was fixed on the equipment customized for the experiment; a slot driver was connected to a MGT12 (Mark-10 Corp.), a torque measurement instrument; the sample had the driver fitted to its RCS and then was rotated until the it was removed; and finally, the maximum torque value was recorded. Result: As for the removal torque measurement results, the average values were $47.9{\pm}2.6Ncm$ for RU, $43.4{\pm}1.5Ncm$ for FC, and $20.9{\pm}1.0Ncm$ for TC. The statistical analysis using Kruskal-Wallis test yielded the significance probability of P<0.05 (P=0.002), which confirmed the presence of significant differences between the three groups. Conclusion: All three cements exhibit clinically acceptable levels of removal torque when applied to an upper zirconia implant restoration fitted with a lingual slot, with RU and FC, the two permanent cements, having the significantly higher values than that of TC, the temporary cement.