A small ultraviolet telescope which can be established on a satellite of the Korean small satellite (KITSAT) series is proposed with a concept design. Possible scientific objectives are identified, and the basic structure and characteristics of the telescope are described. In order to overcome limitation of pointing and stabilization accuracy of the KITSAT, a system of secondary stabilization is designed at the focal plane, where both star-tracking CCD and science detector share a 1.2deg field of view. Star tracking information is fed to three-axis drivers that move the platform on which the star-tracking CCD and science detector are installed. The proposed stabilization system is light and efficient, in comparison with a standard system of stabilization that basically moves the whole telescope or satellite. With a good intensified CCD and second stabilization system, the telescope will achieve a limiting magnitude of 21 at 1600 angstrom, which is sufficient for observing a variety of celestial objects, such as hot stars, nebulae, galaxies with UV excess, and quasars.

Observational trends of the Jovian UV aurora, obtained from the Goddard High Resolution Spectrograph(GHRS) on board the Hubble Space Telescope(HST), are explained by a simple two component model. The model consists of cool and warm components with temperatures of about 400 and 1000K, and with methane absorptions corresponding to column densities of 6-9e16/cm2 and no methane absorption, respectively. Three trends that (1) brighter UV spectra have lower temperatures, and (2) spectra with stronger methane absorption show lower temperatures, and (3) spectra with stronger methane absorption seem to be brighter, are accounted by combinations of two components with various filling factors and intensity ratios. The model implies that precipitating particles responsibie for the cool component have higher individual energy and stronger energy flux than those for the warm component. Estimation of GHRS aperture location on UV auroral images taken by the Wide Field Planetary Camera 2(WFPC2) suggests that the cool component may correspond to emission along the oval, and the warm component to diffuse features of UV emission. Preliminary comparison of images by the WFPC2 and those by H3+ 4 micrometer ground-based observations implies that the warm component causes both weak diffuse features of UV emission and bright H3+ emission in an area at lambda III - 150 deg. inside the northern oval.

We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the 1.5 μm NH3 band, the 2.3 μm CH4 band, the 2.12 μm H2 S(0) pressure-induced absorption, and the continua at 1.58 μm and 2.0 μm (short K-band). All images except those with the 1.58 μm continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about 45° S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric CH4, NH3 or H2. The impact sites observed with the 2.3 μm filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and 2.12 μm filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about 1%. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.

We present for the first time the characteristics of upper atmospheric horizontal winds over the Korean Peninsula. Winds and their variability are derived using four-year measurements by the Korea Astronomy and Space Science Institute (KASI) meteor radar. A general characteristic of zonal and meridional winds is that they exhibit distinct diurnal and seasonal variations. Their changes indicate sometimes similar or sometimes different periodicities. Both winds are characterized by either semi-diurnal tides (12 hour period) and/or diurnal tides (24 hour period) from 80–100 km. In terms of annual change, the annual variation is the strongest component in both winds, but semi-annual and ter-annual variations are only detected in zonal winds.

The ionospheric mid-latitude trough (IMT) is the electron density depletion phenomenon in the F region during nighttime. It has been suggested that the IMT is the result of complex plasma processes coupled to the magnetosphere. In order to statistically investigate the characteristics of the IMT, we analyze topside sounding data from Alouette and ISIS satellites in 1960s and 1970s. The IMT position is almost constant for seasons and solar activities whereas the IMT depth ratio and the IMT feature are stronger and clearer in the winter hemisphere under solar minimum condition. We also calculated transition heights at which the densities of oxygen ions and hydrogen/helium ions are equal. Transition heights are generally higher in daytime and lower in nighttime, but the opposite aspects are seen in the IMT region. Utilizing the Incoherent Scatter Radar (ISR) electron temperature measurements, we find that the electron temperature in the IMT region is enhanced at night during winter. The increase of electron temperature may cause fast transport of the ionospheric plasma to the magnetosphere via ambipolar diffusion, resulting in the IMT depletion. This mechanism of the IMT may work in addition to the simply prolonged recombination of ions proposed by the traditional stagnation model.

We have investigated the variations of sporadic E (Es) layer using the measurements of digisondes at Icheon (37.14°N, 127.54°E, IC) and Jeju (33.4°N, 126.30°E, JJ) in 2011–2018. The Es occurrence rate and its critical frequency (foEs) have peak values in summer at both IC and JJ in consistent with their known seasonal variations at mid-latitudes. The virtual height of the Es layer (h’Es) during equinox months is greater than that in other months. It may be related to the similar variation of meteor peak heights. The h’Es shows the semidiurnal variations with two peaks at early in the morning and late in the afternoon during equinoxes and summer. However, the semi-diurnal variation is not obvious in winter. The semi-diurnal variation is generally thought to be caused by the semi-diurnal tidal variation in the neutral wind shear, whose measurements, however, are rare and not available in the region of interest. To investigate the formation mechanism of Es, we have derived the vertical ion drift velocity using the Horizontal Wind Model (HWM) 14, International Geomagnetic Reference Field, and Naval Research Laboratory Mass Spectrometer and Incoherent Scatter Radar-00 models. Our results show that h’Es preferentially occur at the altitudes where the direction of the vertical ion velocity changes. This result indicates the significant role of ion convergence in the creation of Es.

A Fabry-Perot interferometer (FPI) for mesospheric observations was installed at King Sejong Station (62.2°S, 58.9°W) in Antarctica in 2017. For the initial validation of the FPI measurements, we compare neutral wind data recorded with the FPI with those from a Meteor Radar (MR) located nearby. The overall characteristics of the FPI and MR winds of both OH 892.0 nm (87 km) and OI 557.7 nm (97 km) airglow layers are similar. The FPI winds of both layers generally match the MR winds well on the observed days, with a few exceptions. The correlation analysis of the FPI and MR wind data shows that the correlation coefficients for the zonal winds at 87 and 97 km are 0.28 and 0.54, respectively, and those for the meridional winds are 0.36 and 0.54, respectively. Based on the assumption that the distribution of the airglow emissions has a Gaussian function with respect to the altitude, we calculated the weighted mean winds from the MR wind profile and compared them with the FPI winds. By adjusting the peak height and full width at half maximum of the Gaussian function, we determined the change of the correlation between the two winds. The best correlation for the OH and OI airglow layers was obtained at a peak height of 88–89 km and 97–98 km, respectively.

Jang Bogo Station (JBS), the second Korean Antarctic research station, was established in Terra Nova Bay, Antarctica (74.62°S 164.22°E) in February 2014 in order to expand the Korea Polar Research Institute (KOPRI) research capabilities. One of the main research areas at JBS is space environmental research. The goal of the research is to better understand the general characteristics of the polar region ionosphere and thermosphere and their responses to solar wind and the magnetosphere. Ground-based observations at JBS for upper atmospheric wind and temperature measurements using the Fabry-Perot Interferometer (FPI) began in March 2014. Ionospheric radar (VIPIR) measurements have been collected since 2015 to monitor the state of the polar ionosphere for electron density height profiles, horizontal density gradients, and ion drifts. To investigate the magnetosphere and geomagnetic field variations, a search-coil magnetometer and vector magnetometer were installed in 2017 and 2018, respectively. Since JBS is positioned in an ideal location for auroral observations, we installed an auroral all-sky imager with a color sensor in January 2018 to study substorms as well as auroras. In addition to these observations, we are also operating a proton auroral imager, airglow imager, global positioning system total electron content (GPS TEC)/scintillation monitor, and neutron monitor in collaboration with other institutes. In this article, we briefly introduce the observational activities performed at JBS and the preliminary results of these observations.

The ionosphere has been monitored by ionosondes for over five decades since the 1960s in Korea. An ionosonde typically produces an ionogram that displays radio echoes in the frequency-range plane. The trace of echoes in the plane can be read either manually or automatically to derive useful ionospheric parameters such as foF2 (peak frequency of the F2 layer) and hmF2 (peak height of the F2 layer). Monitoring of the ionosphere should be routinely performed in a given time cadence, and thus, automatic scaling of an ionogram is generally executed to obtain ionospheric parameters. However, an auto-scaling program can generate undesirable results that significantly misrepresent the ionosphere. In order to verify the degree of misrepresentation by an auto-scaling program, we performed manual scaling of all 35,136 ionograms measured at Jeju (33.43˚N, 126.30˚E) throughout 2012. We compared our manually scaled parameters (foF2 and hmF2) with auto-scaled parameters that were obtained via the ARTIST5002 program. We classified five cases in terms of the erroneous scaling performed by the program. The results of the comparison indicate that the average differences with respect to foF2 and hmF2 between the two methods approximately correspond to 0.03 MHz and 4.1 km, respectively with corresponding standard deviations of 0.12 MHz and 9.58 km. Overall, 36 % of the auto-scaled results differ from the manually scaled results by the first decimal number. Therefore, future studies should be aware of the quality of auto-scaled parameters obtained via ARTIST5002. Hence, the results of the study recommend the use of manually scaled parameters (if available) for any serious applications.

Gold kiwifruit was fermented with Lactobacillus plantarum CK10 derived from kimchi and the fermented products were extracted with ethanol at various fermentation time-points The bacterial cellular density, total titratable acidity, total polyphenol content (TPC), and total flavonoid content (TFC) increased during fermentation, while pH values and total soluble solids decreased. Levels of TPC and TFC were highest after five days, at 1.21±0.13 mg GAE/g dry weight and 0.36±0.04 mg RE/g dry weight, respectively. The antioxidant activities of the fermented gold kiwifruit were analyzed using Fe2+ chelating activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH)-, and 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) (ABTS)- radical scavenging activities, and superoxide dismutase (SOD)-like activity. The Fe2+ chelating activity of gold kiwifruit (125-500 μg/mL) peaked after five days of fermentation at 38.40-78.47%. The DPPH radical- scavenging activity and SOD-like activity were somewhat higher after seven days of fermentation (36.01-86.81% and 54.79-93.83% at 2.5-10.0 mg/mL concentration of samples, respectively). On the other hand, the ABTS radical- scavenging activity of fermented gold kiwifruit was similar to that of the non-fermented form. The polyphenol and flavonoid contents were significantly correlated with the antioxidant activity. In conclusion, our results suggest that TPC, TFC, and antioxidant activity were increased after five and seven days of fermentation, respectively. Therefore, fermented gold kiwifruit with its increased antioxidant activity could be useful in the development of functional foods.

Ascidian embryos have become an important model for embryological studies, offering a simple example for mechanisms of cytoplasmic components segregation. It is a well-known example that the asymmetric segregation of mitochondria into muscle lineage cells occurs during ascidian embryogenesis. However, it is still unclear which signaling pathway is involved in this process. To obtain molecular markers for studying mechanisms involved in the asymmetric distribution of mitochondria, we have produced monoclonal antibodies, Mito-1, Mito-2 and Mito-3, that specifically recognize mitochondriarich cytoplasm in cells of the ascidian Halocynthia roretzi embryos. These antibodies stained cytoplasm like reticular structure in epidermis cells, except for nuclei, at the early tailbud stage. Similar pattern was observed in vital staining of mitochondria with DiOC2, a fluorescent probe of mitochondria. Immunostaining with these antibodies showed that mitochondria are evenly distributed in the animal hemisphere blastomeres at cleavage stages, whereas not in the vegetal hemisphere blastomeres. Mitochondria were transferred to the presumptive muscle and nerve cord lineage cells of the marginal zone in the vegetal hemisphere more than to the presumptive mesenchyme, notochord and endoderm lineage of the central zone. Therefore, it is suggested that these antibodies will be useful markers for studying mechanisms involved in the polarized distribution of mitochondria during ascidian embryogenesis.

We retrieved rotational temperatures from emission lines of the OH airglow (8-3) band in the sky spectra of the Sloan digital sky survey (SDSS) for the period 2000-2014, as part of the astronomical observation project conducted at the Apache Point observatory (32°N, 105°W). The SDSS temperatures show a typical seasonal variation of mesospheric temperature: low in summer and high in winter. We find that the temperatures respond to solar activity by as much as 1.2 K ±0.8 K per 100 solar flux units, which is consistent with other studies in mid-latitude regions. After the seasonal variation and solar response were subtracted, the SDSS temperature is fairly constant over the 15 year period, unlike cooling trends suggested by some studies. This temperature analysis using SDSS spectra is a unique contribution to the global monitoring of climate change because the SDSS project was established for astronomical purposes and is independent from climate studies. The SDSS temperatures are also compared with mesospheric temperatures measured by the microwave limb sounder (MLS) instrument on board the Aura satellite and the differences are discussed.

Background : The practice of keeping the medicinal herbs at room temperature causes many problems, but due to lack of sufficient field research and study, it is difficult to improve related regulations and safety management. Methods and Results : The Cnidium Rhizome and Angelica gigas Root were inoculated with Lasioderma serricorne F. and incubated at 28℃ for 2.5 months and 5 months. After five months, the number of Lasioderma serricorne F. in Cnidium Rhizome increased from 30 to 1,429 (about 47 times). In the same period, the number of insects in Angelica gigas Root increased from 30 to 663 (about 22 times). Due to the rapid increase in pest population, hygiene deteriorated, changes in the active ingredient and appearance quality of the herbal medicines, which greatly damaged the value of the herbal medicine. Conclusions : These results show that current regulation requiring only sealing and not specifying the storage temperature do not guarantee quality safety. Therefore, it is necessary to establish appropriate preservation standards and improve management regulations in order to preserve safety.

In South Korea, there are about 80 Global Positioning System (GPS) monitoring stations providing total electron content (TEC) every 10 min, which can be accessed through Korea Astronomy and Space Science Institute (KASI) for scientific use. We applied the computerized ionospheric tomography (CIT) algorithm to the TEC dataset from this GPS network for monitoring the regional ionosphere over South Korea. The algorithm utilizes multiplicative algebraic reconstruction technique (MART) with an initial condition of the latest International Reference Ionosphere-2016 model (IRI-2016). In order to reduce the number of unknown variables, the vertical profiles of electron density are expressed with a linear combination of empirical orthonormal functions (EOFs) that were derived from the IRI empirical profiles. Although the number of receiver sites is much smaller than that of Japan, the CIT algorithm yielded reasonable structure of the ionosphere over South Korea. We verified the CIT results with NmF2 from ionosondes in Icheon and Jeju and also with GPS TEC at the center of South Korea. In addition, the total time required for CIT calculation was only about 5 min, enabling the exploration of the vertical ionospheric structure in near real time.

In animal development, the mechanisms by which localized factors and organelles in egg cytoplasm were exactly distributed into each daughter cell are essential for formation of various cell types. During ascidian Halocynthia roretzi embryogenesis, ooplasmic mitochondria were mainly segregated into muscle and neural precursor cells. At the 32-cell stage, localized mitochondria in the B6.2 blastomeres were preferentially distributed into the B7.4 muscle precursors compared with the B7.3 mesenchyme/ notochord precursors. When the B6.2 blastomeres were isolated from the early 32-cell stage embryos and then allowed to divide 2 times of cell division, the resultant partial embryos showed symmetric distribution of mitochondria, and the partial embryos were composed of equal size cells. In normal development, cell fates of the B7.3 blastomere were correlated with the unequal cleavage of B6.2 lineage cells that normally occurs in the next two-cell division stages to produce a large B8.5 mesenchyme and a small B8.6 notochord cell. Mitochondria are distributed asymmetrically in both cells. When embryos were treated with FGF receptor inhibitor SU5402 and MEK inhibitor U0126 between the 32-cell and the early 64-cell stages, the resultant embryos showed equal cleavage pattern and symmetric distribution of mitochondria in daughter cells of the B6.2 blastomeres. However, blocking of Nodal and Notch signaling did not affect the cell division pattern and mitochondrial distribution in the B6.2 lineage blastomeres between the 32-cell and 110-cell stages. Therefore, it is likely that FGF/MEK signaling is involved in asymmetric distribution of mitochondria and unequal cleavage of the B6.2 lineage blastomeres in ascidian embryo.

Analysis of lunar samples returned by the US Apollo missions revealed that the lunar highlands consist of anorthosite, plagioclase, pyroxene, and olivine; also, the lunar maria are composed of materials such as basalt and ilmenite. More recently, the remote sensing approach has enabled reduction of the time required to investigate the entire lunar surface, compared to the approach of returning samples. Moreover, remote sensing has also made it possible to determine the existence of specific minerals and to examine wide areas. In this paper, an investigation was performed on the reflectance distribution and its trend. The results were applied to the example of the double ray stretched in parallel lines from the Tycho crater to the third-quadrant of Mare Nubium. Basic research and background information for the investigation of lunar surface characteristics is also presented. For this research, resources aboard the SELenological and ENgineering Explorer (SELENE), a Japanese lunar probe, were used. These included the Multiband Imager (MI) in the Lunar Imager / Spectrometer (LISM). The data of these instruments were edited through the toolkit, an image editing and analysis tool, Exelis Visual Information Solution (ENVI).

At the suggestion of the NASA Meteoroid Environment Office (NASA/MEO), which promotes lunar impact monitoring worldwide during NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) mission period (launched Sept. 2013), we set up a video observation system for lunar impact flashes using a 16-inch educational telescope at Chungnam National University. From Oct. 2013 through Apr. 2014, we recorded 80 hours of video observation of the unilluminated part of the crescent moon in the evening hours. We found a plausible candidate impact flash on Feb. 3, 2014 at selenographic longitude 2.1° and latitude 25.4°. The flash lasted for 0.2 s and the light curve was asymmetric with a slow decrease after a peak brightness of 8.7 ± 0.3 mag. Based on a star-like distribution of pixel brightness and asymmetric light curve, we conclude that the observed flash was due to a meteoroid impact on the lunar surface. Since unequivocal detection of an impact flash requires simultaneous observation from at least two sites, we strongly recommend that other institutes and universities in Korea set up similar inexpensive monitoring systems involving educational or amateur telescopes, and that they collaborate in the near future.

In this study, a star identification algorithm which utilizes pivot patterns instead of apparent magnitude information was developed. The new star identification algorithm consists of two steps of recognition process. In the first step, the brightest star in a sensor image is identified using the orientation of brightness between two stars as recognition information. In the second step, cell indexes are used as new recognition information to identify dimmer stars, which are derived from the brightest star already identified. If we use the cell index information, we can search over limited portion of the star catalogue database, which enables the faster identification of dimmer stars. The new pivot algorithm does not require calibrations on the apparent magnitude of a star but it shows robust characteristics on the errors of apparent magnitude compared to conventional pivot algorithms which require the apparent magnitude information.

Since the operation of the King Sejong Station (KSS) started in Antarctic Peninsula in 1989, there have been continuous efforts to perform the observation for the upper atmosphere. The observations during the initial period of the station include Fabry-Perot Interferometer (FPI) and Michelson Interferometer for the mesosphere and thermosphere, which are no longer in operation. In 2002, in collaboration with York University, Canada, the Spectral Airglow Temperature Imager (SATI) was installed to observe the temperature in the mesosphere and lower thermosphere (MLT) region and it has still been producing the mesopause temperature data until present. The observation was extended by installing the meteor radar in 2007 to observe the neutral winds and temperature in the MLT region during the day and night in collaboration with Chungnam National University. We also installed the all sky camera in 2008 to observe the wave structures in the MLT region. All these observations are utilized to study on the physical characteristics of the MLT region and also on the wave phenomena such as the tide and gravity wave in the upper atmosphere over KSS that is well known for the strong gravity wave activity. In this article, brief introductions for the currently operating instruments at KSS will be presented with their applications for the study of the upper atmosphere.