Even in an era where 8-meter class telescopes are common, small telescopes are considered very valuable research facilities since they are available for rapid follow-up or long term monitoring observations. To maximize the usefulness of small telescopes in Korea, we established the SomangNet, a network of 0.4{1.0 m class optical telescopes operated by Korean institutions, in 2020. Here, we give an overview of the project, describing the current participating telescopes, its scientic scope and operation mode, and the prospects for future activities. SomangNet currently includes 10 telescopes that are located in Australia, USA, and Chile as well as in Korea. The operation of many of these telescopes currently relies on operators, and we plan to upgrade them for remote or robotic operation. The latest SomangNet science projects include monitoring and follow-up observational studies of galaxies, supernovae, active galactic nuclei, symbiotic stars, solar system objects, neutrino/gravitational-wave sources, and exoplanets.

Metal matrix composites(MMC) can obtain mechanical characteristics of application purposes that a single material is difficult to obtain. Al2 O3/AC8A composites were fabricated by low pressure infiltration process. The purpose is establishing the optimal casting conditions for composite preparation under low pressure. It is known the inorganic binder help infiltration. Therefore Al2O3 fiber preform's optimum sinter temperature is 1160℃, added inorganic binder is mixed binder(SiO2 sol:Al2O3 sol=5:2). And three fibers have been compared (Al2O3 80%/SiO2 20%, Al2O3 80%/SiO2 10% and Al2O3 97%/SiO2 3%). Al2O3/AC8A composites was made by each melting temperatures(650℃, 700℃, 750℃) and wear test was performed about effect of temperatures, kind of fiber, matrix and composites, aging time. Wear test is Ball on disk wear test. The resistance increased with the low melting temperature and Al2O3 80%/SiO2 20% fiber.

In ruminants, Interferon-τ (IFN-τ) has the role of recognizing pregnancy signals produced by the embryo and it may have an important role during the luteolysis. Therefore, the purpose of the present study was to investigate the effect of IFN-τ on prostaglandin synthesis, cyclooxygenase-2 (COX-2) gene expression in vitro and secretion of progesterone (P4) in vivo. The epithelial and stromal cells isolated from bovine endometrium were cultured with different doses of IFN-τ (0, 0.02, 0.2 and 2 μg/ml). Human chorionic gonadotropin (hCG, 1.5 IU/ml) was used as a positive control. Prostaglandin E2 and F2α levels in the culture media were analyzed by enzyme immunoassays, and total RNA was extracted from the cells for RT-PCR. P4 concentrations in blood samples were assayed by chemiluminescent immunoassay system. In epithelial cells, COX-2 gene expression was increased in the presence of IFN-τ (p<0.05), but it was not significantly different in all groups of stromal cells except 2 μg/ml IFN-τ group (p<0.05). Although IFN-τ did not affect PGE2 and PGF2α production in epithelial cells, it decreased PGE2 and PGF2α production significantly in stromal cells (p<0.05). In vivo experiment, the P4 concentrations in blood sample was significantly increased after injection of 1 μg/ml IFN-τ. These results indicate that PG production was mediated by COX-2 expression in the stromal cells but it did not affect in the epithelial cells, and suggest that treatment of IFN-τ was to improve the implantation environment of uterine by maintenance of high P4 concentration. * This work was carried out with the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project No. PJ907008)” Rural Development Administration, Republic of Korea.

We have made a comprehensive statistical study on the coronal mass ejections(CMEs) associated with helmet streamers. A total number of 3810 CMEs observed by SOHO/LASCO coronagraph from 1996 to 2000 have been visually inspected. By comparing their LASCO images and running difference images, we picked out streamer-associated CMEs, which are classified into two sub-groups: Class-A events whose morphological shape seen in the LASCO running difference image is quite similar to that of the pre-existing streamer, and Class-B events whose ejections occurred in a part of the streamer. The former type of CME may be caused by the destabilization of the helmet streamer and the latter type of CME may be related to the eruption of a filament underlying the helmet streamer or narrow CMEs such as streamer puffs. We have examined the distributions of CME speed and acceleration for both classes as well as the correlation between their speed and acceleration. The major results from these investigations are as follows. First, about a quarter of all CMEs are streamer-associated CMEs. Second, their mean speed is 413 km s-1 for Class-A events and 371 km s-1 for Class-B events. And the fraction of the streamer-associated CMEs decreases with speed. Third, the speed-acceleration diagrams show that there are no correlations between two quantities for both classes and the accelerations are nearly symmetric with respect to zero acceleration line. Fourth, their mean angular width are about 60°, which is similar to that of normal CMEs. Fifth, the fraction of streamer-associated CMEs during the solar minimum is a little larger than that during the solar maximum. Our results show that the kinematic characteristics of streamer-associated CMEs, especially Class-A events, are quite similar to those of quiescent filament-associated CMEs.