검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 50

        41.
        2016.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        As described in the previous paper (Park et al. 2013), the detector subsystem of optical wide-field patrol (OWL) provides many observational data points of a single artificial satellite or space debris in the form of small streaks, using a chopper system and a time tagger. The position and the corresponding time data are matched assuming that the length of a streak on the CCD frame is proportional to the time duration of the exposure during which the chopper blades do not obscure the CCD window. In the previous study, however, the length was measured using the diagonal of the rectangle of the image area containing the streak; the results were quite ambiguous and inaccurate, allowing possible matching error of positions and time data. Furthermore, because only one (position, time) data point is created from one streak, the efficiency of the observation decreases. To define the length of a streak correctly, it is important to locate the endpoints of a streak. In this paper, a method using a differential convolution mask pattern is tested. This method can be used to obtain the positions where the pixel values are changed sharply. These endpoints can be regarded as directly detected positional data, and the number of data points is doubled by this result.
        42.
        2016.05 서비스 종료(열람 제한)
        Background : The purpose of the present investigation is to enhance extracellular acidic protease production by subjecting a protease producing strain Cordyceps pruinosa DK-01 to random mutagenesis by UV irradiation after ethidium bromide treatment. Methods and Results : Mutants were screened as protease producers on the basis of zone of clearance and relative proteolytic activity (RPA) on skimmed milk agar plates. In addition, mutants showed strong pink-red color intensity and different RAPD profiling compared with wild type control. Four mutants were randomly selected and their extracellular enzyme activities were investigated. In liquid culture without casein, 2.2-, 2.9-, 5.2- and 4.4-fold higher acid protease activity was achieved from mutants DK-m9, -m11 and -m12, respectively, than that of wild type strain (11.13 ± 1.60 U/ml). In liquid culture with casein, 1.1-, 1.3-, 1.3 and 1.3-fold higher acid protease activity was achieved with those mutants were found to produce, respectively, than that of wild type strain (93.95 ± 12.84 U/ml). Maximum acid protease activity was noticed from a mutant DK-m11 in liquid culture with casein (121.18 U/ml) and without casein (57.65 U/ml). The extracellular acid protease produced from DJ-m11 that was active in the pH range 4.5-6.5 and optimum temperature for the activity was 37°C. Furthermore, we found a deformed, shorten structure of setae on the elytron surface of dynastid beetles treated with culture supernatant of the DK-m11. Conclusion : These findings have more impact on enzyme economy for biotechnological and insecticidal applications of fungal proteases.
        43.
        2015.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        To protect and manage the Korean space assets including satellites, it is important to have precise positions and orbit information of each space objects. While Korea currently lacks optical observatories dedicated to satellite tracking, the Korea Astronomy and Space Science Institute (KASI) is planning to establish an optical observatory for the active generation of space information. However, due to geopolitical reasons, it is difficult to acquire an adequately sufficient number of optical satellite observatories in Korea. Against this backdrop, this study examined the possible locations for such observatories, and performed simulations to determine the differences in precision of optical orbit estimation results in relation to the relative baseline distance between observatories. To simulate more realistic conditions of optical observation, white noise was introduced to generate observation data, which was then used to investigate the effects of baseline distance between optical observatories and the simulated white noise. We generated the optical observations with white noise to simulate the actual observation, estimated the orbits with several combinations of observation data from the observatories of various baseline differences, and compared the estimated orbits to check the improvement of precision. As a result, the effect of the baseline distance in combined optical GEO satellite observation is obvious but small compared to the observation resolution limit of optical GEO observation.
        44.
        2012.07 서비스 종료(열람 제한)
        To produce abiotic stress resistant transgenic cucumber, the cotyledonary node explants of cucumber (c.v. Eunsung) were inoculated with A. tumefaciens strain EHA105 containing the binary vector (pPZP211) carrying Nit gene. The 491 explants inoculated with bacterium solution for 30 min were maintained on 50 mg/L paromomycin contained shoot induction (SI) medium for first 2 weeks and then subcultured on 100 mg/L paromomycin to obtain transgenic adventitious shoots for 4 x 14 days. So far, 5 plant were selected, and then acclimated in soil. Of them, 3 transgenic plants with Nit gene were confirmed by Southern blot analysis.
        46.
        2011.09 서비스 종료(열람 제한)
        Human embryonic stem cells (hESCs) have the potential for use in regenerative medicine and in the field of basic research. Therefore, effective cryopreservation and storage of hESCs are important for preservation of newly established cell line for various purposes. Despite poor survival and slow recovery after thawing, the conventional slow freezing method is most commonly used for cryopreservation of hESCs due to its simplicity and ease of use for freezing a large number of hESCs appropriate to clinical applications. Here we controlled the clump size (Group Ⅰ; 400~450 ㎛, Group Ⅱ; 800~900 ㎛, and Group Ⅲ; 1500~1700 ㎛) of hESCs at 5 days after plating using a glass pipette during cryopreservation in order to obtain a larger amount of hESCs after thawing. Attachment rates differed significantly (P<0.05) in each of the three groups and the average of attachment rate of GroupⅡ was highest in SNUhES4 and H1. In particular, the attachment rate of Group Ⅱ in SNUhES3 showed a significant improvement with ROCK inhibitor Y-27632. These results indicate that clump size and cell-cell adhesions of GroupⅡ are appropriate for cryopreservation compared to the Group Ⅰ and Group Ⅲ. This method increased cell viability and reduced the recovery time leading to various experiments, and therefore has an advantage for use with hESCs like newly established in particular. We demonstrated that use of this effective cryopreservation method with control of the clump size of hESCs can effectively improve the attachment rate and survival of post-thaw hESCs with and without Y-27632.
        48.
        2007.06 KCI 등재 서비스 종료(열람 제한)
        Hopyeongbyeo is an anther culture derived Japonica rice (Oriza sativa L.) cultivar from the cross between Hitomebore and Hwajinbyeo by the rice breeding team of Honam Agricultural Research Institute (HARI), NICS, RDA, in 2003. This cultivar has a about 126 days growth duration from transplanting to harvesting. The short and round grain shape of Hopyeongbyeo is translucent with non-glutinous endosperm. Amylose content of rice grain is about 17.8% and high palatability of cooked rice compared with Nampyeongbyeo. This cultivar shows resistant to bacterial blight pathogenes of K1. The milled rice yield of Hopyeongbyeo is about 5.13MT/ha at ordinary transplanting culture in the local adaptability test. Hopyeongbyeo would be adaptable for the southern plain area of Korea.
        49.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        ‘Gwangan’ is a new six-rowed covered barley cultivar developed by the National Institute of Crop Science (NICS), R.D.A in 2004. This cultivar is developed from a cross between “Mirak” and ‘Milyang59’ in 1995. An F6 selection was made at Milyang in 2001 an
        1 2 3