Simultaneous time monitoring observations of H2O and SiO maser lines were performed toward the D-type symbiotic binary system V407 Cyg with the Korean VLBI Network single dish radio telescope. These monitoring observations were carried out from March 2, 2010 (optical phase  = 0.0), 8 days before the nova outburst on March 10, 2010 to June 5, 2014 ( = 2.13). Eight days before the nova outburst, we detected the SiO v = 1, 2, J = 1–0 maser lines which exhibited values of 0.51 K ( 6.70 Jy) and 0.71 K ( 9.30 Jy), respectively, while after the outburst we could not detect them on April 2 ( = 0.04), May 5 ( = 0.09), May 8 ( = 0.09), or on June 5, 2010 ( = 0.13) within the upper limits of our KVN observations. After restarting our monitoring observations, we detected SiO v = 2, J = 1–0 masers starting on October 20, 2011 ( = 0.83) and detected SiO v = 1, J = 1–0 masers starting on December 22, 2011 ( = 0.92). These results provide clear evidence of the interaction between the shock from the nova outburst and the SiO maser regions of the Mira envelope. The peak emission of SiO v = 1, 2, J = 1–0 masers always occurred at blueshifted velocities with respect to the stellar velocity except for that of SiO v = 1 at one epoch. These phenomena may be related to the redistribution of SiO maser regions after the outburst. The peak velocity variations of SiO masers associated with stellar pulsation phases show an increasing blueshifted trend during our monitoring interval after the outburst.

Simultaneous time monitoring observations of H2O 616 − 523, SiO J = 1–0, 2–1, 3–2, and 29SiO v = 0, J = 1–0 lines are carried out in the direction of the Mira variable star TX Cam with the Korean VLBI Network single dish radio telescopes. For the first time, the H2O maser emission from TX Cam is detected near the stellar velocity at five epochs from April 10, 2013 (Ø = 3.13) to June 4, 2014 (Ø = 3.89) including minimum optical phases. The intensities of H2O masers are very weak compared to SiO masers. The variation of peak antenna temperature ratios among SiO v = 1, J = 1–0, J = 2–1, and J = 3–2 masers is investigated according to their phases. The shift of peak velocities of H2O and SiO masers with respect to the stellar velocity is also investigated according to observed optical phases. The H2O maser emission occurs around the stellar velocity during our monitoring interval. On the other hand, the peak velocities of SiO masers show a spread compared to the stellar velocity. The peak velocities of SiO J = 2–1, and J = 3–2 masers show a smaller spread with respect to the stellar velocity than those of SiO J = 1–0 masers. These simultaneous observations of multi-frequencies will provide a good constraint for maser pumping models and a good probe for investigating the stellar atmosphere and envelope according to their different excitation conditions.

We report the development of solar flux receivers operating at 2.8 GHz to monitor solar radio activity. Radio waves from the sun are amplified, filtered, and then transmitted to a power meter sensor without frequency down-conversion. To measure solar flux, a calibration scheme is designed with a noise source, an ambient load, and a hot load at 100℃. The receiver is attached to a 1.8 m parabolic antenna in Icheon, owned by National Radio Research Agency, and observation is being conducted during day time on a daily basis. We compare the solar fluxes measured for last seven months with solar fluxes obtained by DRAO in Penticton, Canada, and by the Hiraiso solar observatory in Japan, and finally establish equations to convert observed flux to the so-called Penticton flux with an accuracy better than 3.2 sfu.

This study investigated the antimicrobial activity of methanol extract of mulberry leaf against 16 strains of mutans streptococci and four species of periodontopathogens: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extracts or silica gel chromatography fractions of methanol-extracted mulberry leaf were evaluated by determining minimal inhibitory concentrations using an established microdilution method. The cytotoxicity of the extracts of mulberry leaf on KB cells was tested by the methyl thiazolyl tetrazolium assay. Chromatography fraction 12 displayed the most potent antimicrobial activity against all 16 strains of mutans streptococci, P. gingivalis, and P. intermedia. No KB cell cytotoxicity was evident up to 128μg/ml of fraction 12. The methanol extract had no antimicrobial activity against F. nucleatum and A. actinomycetemcomitans. These results suggest chromatography fraction 12 methanol extract of mulberry leaf could be useful in the development of oral hygiene products, such as dentifrice and oral hygiene solution, for the prevention of dental caries.

The aim of this study was to investigate antimicrobial effect of oleanolic acid (OA), ursolic acid (UA), and sophoraflavanone G against Enterococcus faecalis and Propionibacterium acnes, which are the major causative bacteria of endodontic infections. The antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC). The data showed that the OA, UA, and sophoraflavanone G had antimicrobial effect on all the strains use in the study with 16-64 µg/ml, 8-64 µg/ml, and 1-8 µg/ml of MIC values, respectively. These results indicate that OA, UA, and sophoraflavanone G could be useful in the development of antiseptic solution for washing the root canal in endodontic treatments.

In order to fabricate complex-shaped polycrystalline ceramics by sintering, organic binders are usually pre-mixed with ceramic powders to enhance the formability during the shape forming process. These organic binders, however, must be eliminated before sintering so as to eliminate the possibilities of poor densification and unusual grain growth during sintering. The present work studies the effect of binder addition on grain growth behavior during sintering of piezoelectric ceramics. The microstructures of the sintered samples were examined for various heating profiles and debinding schedules of the binder removal process. Addition of Polyvinyl butyral(PVB) binder promoted abnormal grain growth especially in incompletely debinded regions. Residual carbon appears to change the grain shape from comer-rounded to faceted and enhance abnormal grain growth

1995년도 1996년 6월에 실시된 CREAMS 항해 관측 자료를 이용하여 Wasaka bay 연안역의 수온역전 현상을 조사하였다. 수온역전현상은 대부분 20m 이천의 상층부에 위치하였으며, 특히 쓰시마난류와 연안수와의 경계역 부분에 형성되었다. 쓰시마난류는 고온·고염분수의 특징을 가지며, 이러한 고수온은 경계역 부분에서 수온역전 현상을 초래하여 밀도 역전현상을 일으키는 작용을 하는 반면, 고염분은 밀도를 증가시켜 주는 작용을 하여 수온역전에 따른 밀도역전현상을 막아주는 역할을 한다.

1996년 6월에 실시된 CREAMS 항해 관측 자료를 이용하여 동해 남부 해역의 해황을 분석하였다. 1996년은 1990년∼1999년 사이의 다른 해에 비해 동해 남부 해역에 저수온 현상이 나타났으며, 이러한 현상은 일본 연안을 따라 이동하는 쓰시마난류의 지류가 더욱더 연안에 근접하여 이동하는 것과 관련이 있다. 쓰시마난류의 분포는 수심 200m 이천의 대륙붕 위에 존재하는 core 형태의 고염분수 분포와 지형류의 분포로부터 확인된다. 해수의 안정도 계산결과로부터 고온 고염분수인 쓰시마 난류의 유입은 연안역의 연직 밀도 구조에 영향을 주게 되며, 이로 인하여 수주의 불안정한 상태를 초래하는 요인 중 한가지로 작용하는 것으로 나타난다.

We have investigated one dimensional steady flow model of a typical magnetic flux tube in the solar transition region constrained to observed Differential Emission Measure (DEM) for the average quiet-Sun deduced by Raymond & Doyle (1981) with a flux tube geometry conforming to Doppler shifts of UV lines measured by Chae, Yun & Poland (1998). Because local heating and filling factor in the transition region are not well known, we considered two extreme cases, one characterized by the filling factor= 1 ('filled-up model') and the other set by local heating=0 ('not-heated model'). We examined how much the heating is required for the flux tube by recomputing a model through adjustment of the filling factor in such a way that 'not-heated model' accounts for the observed DEM.

To understand the basic physics underlying large spatial fluctuations of intensity and Doppler shift, we have investigated the dynamical charctersitics of the transition region of the quiet sun by analyzing a raster scan of high resolution UV spectral band containing H Lyman lines and a S VI line. The spectra were taken from a quiet area of 100"×100" located near the disk center by SUMER on board SOHO. The spectral band ranges from 906 Å to 950 Å with spatial and spectral resolution of 1" and 0.044 Å, respectively. The parameters of individual spectral lines were determined from a single Gaussian fit to each spectral line. Then, spatial correlation analyses have been made among the line parameters. Important findings emerged from the present analysis are as follows. (1) The integrated intensity maps of the observed area of H I 931 line (1×10 4 K) and S VI 933 line (2×10 5 K) look very smilar to each other with the same characterstic size of 5". An important difference, however, is that the intensity ratio of brighter network regions to darker cell regions is much larger in S VI 933 line than that in H I 931 line. (2) Dynamical features represented by Doppler shifts and line widths are smaller than those features seen in intensity maps. The features are found to be changing rapidly with time within a time scale shorter than the integration time, 110 seconds, while the intensity structure remains nearly unchanged during the same time interval. (3) The line intensity of S VI is quite strongly correlated with that of H I lines, but the Doppler shift correlation between the two lines is not as strong as the intensity correlation. The correlation length of the intensity structure is found to be about 5.7' (4100 km), which is at least 3 times larger than that of the velocity structure. These findings support the notion that the basic unit of the transition region of the quiet sun is a loop-like structure with a size of a few 10 3 km, within which a number of unresolved smaller velocity structures are present.

배추좀나방과 담배거세미나방 유충에 대한 30종 한방 식물체 메탄올 조추출몰의 살충활성 및 섭식 저해활성을 잎침지법을 이용하여 5,000ppm으로 검정하였다. 황련의 추출물은배추좀나방에 대해 살충작용을 보였다. 길경, 사삼, 세신, 오배자 및 자초의 추출물은 배추좀나방 유충에 대해, 목통 및 속새의 추출물은 담배거세미나방 유충에 대한 강한 섭식저해활성을 보였으나, 오배자와 황련의 추출물은 이들 나비목 유충 모두에 강한 섭식저해활성을 나타내었다.

Magnetostatic models of starspots of late type main sequence stars ( G 5 V \~ K 5 V ) have been constructed to investigate their physical characteristics by using the similarity law suggested by Schluter and Temesvary(1958) and later employed by Deinzer(1965) and Yun(1968). The starspots are assumed to be single, circular and in horizontal magnetostatic equilibrium. In the present study we considered only those model spots whose area covers less than 12 % of the entire stellar surface as suggested by observations. The computed surface field strength of our model spots ranges from 10 3 \;to\;several\;10^3$ gauss and their magnetic flux is found to be 10 \~ 100 times that of sunspots. The field strength is sensitive to spectral type, which increases with later spectral type. In contrast to the field strength, the area of starspots depends strongly on the total magnetic flux. Finally, it is noted that the computed field strength of model spots belonging to G 0 V \~ G 5 V falls below the equipartition field strength at their parent stellar surface unless the coverage is less than 2 % . This suggests that the observed spot on G 0 V \~ G 5 V stars is likely to be a group of small starspots.