• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.379-385
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• 2010

This study was carried out to develop cultivation techniques of Climacium japonicum in transparent pot. We analyzed effect of different soil moisture content, air exposure degree, bed soil and ground cover moss on the growth of Climacium japonicum. The best humidity condition in transparent pot culture was 60~80% and a mixture of bed soil with peatmoss : perlite as 7:3 ratio was effective to growth. Two holes(each diameter is 4 mm) in the cover were also effective to the growth and control moisture in the transparent pot. The best mixture of bed soil was moss with peatmoss : pelite(7:3) in the pot culture but price of moss is expensive, the moss treatment was not practical. Total of 10 moss species were selected as ground cover plant; Hypnum erectiusculum Sull. et Lesq., Thuidium kanedae Sak., Hypnum plumaeforme Wils., Trachycystis microphylla Lindb., Bryum argenteum Hedw., Hypnum oldhamii Jaeg., Funaria hygrometrica Hedw., Leucobryum glaucum Aongstr., Polytrichum commune Hedw. and Weissia controversa Hedw. The plant height of selected moss was smaller than that of Climacium japonicum so these moss were very effective to cover the ground.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.298-307
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• 2010

The purpose of this study was to assess the effect on oxygen inhibition layer(OIL) for the interfacial bonding between resin composite layers, including shear bond strength, fracture modes and degree of conversion. The first layer of specimen was filled with Z-250(shade A3) and was cured for 40s. The second layer of specimen was filled with same composite(shade A1) and was cured for 40s. The first layer of specimens for each group were prepared by methods as followings. Control(curing in atmospheric air), Group1(curing against Mylar strip), Group2(scrubbed with a acetone-soaked cotton), Group3(using Tescera light cup), Group4(using Tescera heat cup), Group5(stored in disti1led water for 30days at $37^{\circ}C$), Group6 (using bonding agent). The results were as follows: 1. There was no statistically significant different shear bond strength between control and group 1(p>0.05). 2. Group 2 showed significantly lower shear bond strength than control and group 1(p<0.05). 3. The observation of the fracture surface leads to the evidence that a major difference occurs in the case of control, group1 and group 3 samples which break mainly cohesively while the other groups break in majority adhesively. 4. The results of FTIR showed that the degree of conversion was the highest in group 2 and the lowest in control group(p<0.05). It can be concluded that an OIL is not necessary for bonding with composite resin. But if a reduced critical amount of the unreacted monomer is present, it was detrimental to bonding additional layers of composite. Further study, such as the quantitative analysis of the unreacted monomer are required.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.363-369
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• 2018

A salivary testing instrument has an advantage that the method is simple and can be performed in a short time. However, it is necessary to verify the factors that affect the reliability of the result, because the device is easy to use and even saliva collection is simple. The aim of this study was to compare the difference of the test results according to the measurement time in order to analyze the time factor of the external variable among the factors that may affect the measurement results of the salivary testing instrument. The relationship between the measured values of the salivary testing instrument to identify the internal variables was analyzed. Saliva was collected from 20 randomly selected patients regardless of age, sex, or diseases. The mean age was 46.6 years, 10 males and 10 females. The saliva collected was directly measured with the salivary testing instrument as group I. The saliva samples were placed in air in a paper cup for 10 minutes, and then measured as group III. Then group I was remeasured after 30 minutes and assigned as group II. Group III was remeasured after 30 minutes and called as group IV. As a result, all of the cariogenic bacteria, acidity, buffer capacity, blood, leukocyte, protein and ammonia, except buffer capacity, showed statistically significant changes in group II and IV. This means that the reliability of the test results is poor if the measurement time is not observed. Cariogenic bacteria were correlated with leukocyte and protein, buffer capacity was related to acidity, protein, and protein was related to buffer capacity and leukocyte. In conclusion, the result according to the measurement time as the external variable was different, which means that time must be strictly monitored when testing saliva. It is also necessary to take into account the relevance of the correlations between the internal variables and the clinical data.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.78-91
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• 2012

The Terrestrial DTV service compliant with ATSC has been advancing for years. In KBA(Korean Broadcasters Association), a multi-channel service was broadcasted on air during the period of the 2006 FIFA World Cup Germany with the various type of MMS(Multi Mode Service) using MPEG-2 encoding method. MMS Service can provides not only one HD channel but also serveral additional services within 6MHz bandwidth. Using digital video compression technology(MPEG-2), many various programs such as HDTV, SDTV, Audio and Data are able to be transmitted within the same bandwidth. From November 2009, KBS has been preparing an advanced MMS service, 'Korea-View' which has both methods of encoding, MPEG-2 and H.264 that is compliant ATSC mobile standard, A/153. Korea-View is a kind of multi-channel broadcast service to provide one HD and 3 SD programs with the bandwidth of 6MHz. Terrestrial multi-channel service is required to focuse on expanding viewer service. Such Terrestrial multi-channel services will contribute to transferring to digital broadcasting and to extending the viewers' welfare. Due to advances in digital technology, Pay-TV channels has increased to hundreds. Even though digital switchover is being proceeded, terrestrial broadcasters have been unable to deliver multi-channel services. In this paper, technical features and differences of MMS and Koreaview will be analyzed regarding terrestrial multi-channel broadcasting services, and the politic direction will be proposed in accordance with introduction of future service.