• New & Renewable Energy
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• v.4 no.2
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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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• v.10 no.1
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• pp.94-100
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• 1986

Korean red ginseng tails was extracted with solutions having various ethanol concentration at the temperature range of 70-$100^{\circ}C$, Extraction was carried out for 1-5 times of 8 hours at given condition. Sensory properties and color of RG-Ext. were found to be significantly affected by conditions of extraction. Absorbance at 490nm was decreased as the ethanol concentration increased, the increase in ethanol concentration also showed an increase in the Hunter's values of "L" and "b", and a decrease in "a" value indicating the color of RG-Ext. was changed to yellowish with less in darkness. Increase in extraction time and temperature caused darker brown color which is indicates a typical phenomena of non-enzymatic browning reaction. The flavor and bitternes of RG-Ext. were found to be significantly increased as the ethanol concentration increase, the generally responses of acceptance range of ethanol concentration was 30-70%.

• Journal of Ginseng Research
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• v.10 no.1
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• pp.36-44
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• 1986

Fresh ginseng roots were extracted by different extraction methods to estimate the amount of extracts, and the content of common constituents and ginsenosides for comparison. The results are as follows: 1 The amount of the extract obtained by water as a solvent was about five times higher than those by ethanol or pressing process. 2. Water extraction at 70-$80^{\circ}C$ gave highest value in saponin yield, which was reduced by half by boiling, 3. The saponin yield by pressing process was shown to be about 52% of total saponin; saponins belonging to protopanaxatriol-ginsenosides being extracted better than those belonging to proto-panaxadiol-ginsenosides . 4. The contents of total sugar, reducing sugar, crude protein and total amino acids in the water extract were revealed to be higher compared to those in an ethanol extract. 5. The extract obtained by press had the highest ash content.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.228-232
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• 1992

Magnetic properties of grain aligned high $T_c\;Y_1Ba_2Cu_3O_{7-y}$ superconductor are inverstigated. Grain-aligned superconductors have magnetic anisotropy in the Cu-O layer like single crystals. The lower critical field $H_{c1},$ measured at the temperature range of 2 K up to 77 K, is found to be decreasing linearly as temperature goes up. Moreover, it decreaes more rapidly when the Cu-O layer is perpendicular to the external magnetic field. The temperature dependence of the magnetic susceptibility shows that the value of magnetic susceptibility, $4{\pi}\;X,$ is close to -1 at low temperature. The intra grain critical current density $J_c,$ obtained from the Bean's critical state model, is found to be comparable to that of single crystal superconductors.

• Journal of the Korea Computer Industry Society
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• v.9 no.1
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• pp.21-28
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• 2008

In this paper, the edge parameters were drawn from speaking image around lip and effective automatic lip reading system to recognize the Korean 'a/e/i/o/u' 5 owels were constructed using the parameter. Speaking images around lip were divided into $5{\times}5$ pane. In each pane the number of digital edge element using Sobel operator were evaluated. The observational error between samples was corrected by using normalization method and the normalized value is used for parameter In the experiment to convince the strength of parameter, 50 normal persons were sampled. The images of 10 persons were analyzed and the images of another 40 persons were experimented for recognition. 500 data are gathered and analyzed. Based on this analysis, the neural net system is constructed and the recognition experiments are performed for 400 data. The neural net system gave the best recognition result of 91.1%.

• Journal of Oral Medicine and Pain
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• v.18 no.2
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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.

• The Korean Journal of Applied Statistics
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• v.22 no.2
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• pp.261-270
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• 2009

Current financial crisis triggered by shaky U.S. banking system adds to the emphasis on the importance of the volatility in controlling and understanding financial time series data. The ARCH and GARCH models have been useful in analyzing economic time series volatilities. In particular, multivariate GARCH(MGARCH, for short) provides both volatilities and conditional correlations between several time series and these are in turn applied to computations of hedge-ratio and VaR. In this short article, we try to assess various MGARCH models with respect to the back-testing performances in VaR study. To this end, 14 korean stock prices are analyzed and it is found that MGARCH outperforms rolling window, and BEKK and CCC are relatively conservative in back-testing performance.

• Journal of Environmental Science International
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• v.22 no.11
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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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• v.16 no.11
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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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• v.11 no.1
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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.