검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 21

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since maize (Zea mays L.) originated in central and south America, it requires warm climate conditions throughout its growing season. Growth halts when night-time temperatures drop below 10℃, and the plant may die if temperature reach -1.7℃. Thus, temperature should be maintained between 10 and 30℃ from seeding to maturity. The germination temperature for maize should be at least 8-11℃, whit an optimal range 32-34℃. Since temperature significantly affects the germination rate and period, it plays a crucial role in maize growth. In this study, we evaluated the quantity and feed value of 11 major varieties to determine those best suited for maize cultivation as feed in higher latitude, specifically in Democratic People’s of Republic of Korea, below 38 degrees north. A cultivation test was also conducted in Suwon in Republic of Korea, to assess adaptability in areas south of Mt. Suyang. Among the varieties tested, Shinhwangok2 reached silking the fastest, in 65 days, while Gwangpyeongok took the longest at 75 days. The stem length of all varieties exceeded 230 cm. Gwangpyeongok had the tallest stems, while Daanok and Shinhwangok2ho displayed the highest ear ratios. Dacheongok presented the highest values in both dry matter and TDN quantity, with 31,420 kg/ha and 21,66 kg/ha respectively. Pyeonggangok had the highest crude protein content at 8.0%. TDN (%) ranged from 57-68%, with Hwangdaok reaching up to 68%. Based on these findings, Dacheongok and Pyeonggangok appear to be the most suitable varieties for cultivation in terms of both quantity and feed value.
        4,000원
        5.
        2006.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We carried out CO survey toward IR-excess clouds using SRAO 6-m telescope in search of molecular H2. These clouds, which show far-infrared excess over what is expected from HI column density, are considered to be candidates of molecular clouds. In order to find new high Galactic latitude clouds, we made mapping observations for 14 IR-excess clouds selected from Reach et al.(1998) in 12CO J = 1 - 0 line, supplementing the similar survey in southern hemisphere (Onishi et al. 2001). 12CO emission is detected from three IR-excess clouds among 14 objects. Three newly detected clouds exhibit somewhat clumpy morphology and column densities amount to ~ 1021 cm-2. One of three clouds, DIR120-28, show discrepancy between IR-excess center and CO emission center. It seems that IR-excess may not be an effective tracer of molecular gas. Instead, optical depth(τ) excess, i.e., IR-excess corrected for temperature dependence, may be more effective tracer of molecular clouds, since, by combining statistics from both hemispheres, we found that the detection rate is higher for IR-excess clouds with lower dust temperature.
        4,000원
        8.
        2002.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have mapped 1 deg2 region toward a high latitude cloud MBM 40 in the J = 1 - 0 transition of 12CO and 13CO, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. We used a high resolution autocorrelator to resolve extremely narrow CO linewidths of the molecular gas. Though the linewidth of the molecular gas is very narrow (FWHP < 1 km s-1), it is found that there is an evident velocity difference between the middle upper part and the lower part of the cloud. Their spectra for both of 12CO and 13CO show blue wings, and the position-velocity map shows clear velocity difference of 0.4 km s-1 between two parts. The mean velocity of the cloud is 3.1 km s-1. It is also found that the linewidths at the blueshifted region are broader than those of the rest of the cloud. We confirmed that the visual extinction is less than 3 magnitude, and the molecular gas is translucent. We discussed three mass estimates, and took a mass of 17 solar masses from CO integrated intensity using a conversion factor 2.3 × 10 20 cm -2 (K km s-1)-1. Spatial coincidence and close morphological similarity is found between the CO emission and dust far-infrared (FIR) emission. The ratio between the 100 f.Lm intensity and CO integrated intensity of MBM 40 is 0.7 (MJy/sr)/(K km s-1), which is larger than those of dark clouds, but much smaller than those of GMCs. The low ratio found for MBM 40 probably results from the absence of internal heating sources, or significant nearby external heating sources.
        4,000원
        9.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The investigation of the space environment requires the use of experimental and theoretical tools and resources in order to perform the research task. Understanding of these research tools is imperative for proper interpretation of the results. In this paper, we discuss on research tools that are widely used in the field of aeronomy; Fabry-Perot interferometer and Michelson interferometer. These instruments have been used extensively as passive optical devices, spectrally monitoring the natural atmospheric emissions (airglow). This function has made both instruments valuable tools in upper atmospheric studies since they provide the ability to determine the dynamic and thermodynamic properties of the upper atmosphere by monitoring naturally-occuring emission.
        4,000원
        10.
        2000.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have investigated the properties of the high-latitude cloud MBM 7 using the 3 mm transitions of CO, CS, HCN, HCO+,C3H2,N2H+, and SiO. The molecular component of MBM 7 shows a very clumpy structure with a size of ≤0.5 pc, elongated along the northwest-southeast direction, perpendicularly to an extended HI component, which could be resulted from shock formation. We have derived physical properties for two molecular cores in the central region. Their sizes are 0.1-0.3 pc and masses 1-2 M⊙ having an average volume density ~2×10 3 cm-3 at the peak of molecular emission. We have tested the stability of the cores using the full version of the virial theorem and found that the cores are stabilized with ambient medium, and they are expected not to be dissipated easily without external perturbations. Therefore MBM 7 does not seem to be a site for new star formation. The molecular abundances in the densest core appear to be much less (by about one order of magnitude) than the 'general' dark cloud values. If the depletions of heavy elements are not significant in the HLCs compared with those in typical dark clouds, our results may suggest different chemical evolutionary stages or different chemical environments of the HLCs compared with dense dark clouds in the Galactic plane.
        4,000원
        11.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We have mapped 1 deg2 region toward a high latitude HII region S73 (l, b) = (37°.69, 44°.55) and associated molecular cloud in 12CO J = 1 - 0, and 13CO J = 1 - 0, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. A high resolution autocorrelator is used to resolve extremely narrow CO linewidths (FWHP < 1 km/s) of the molecular cloud. Though the linewidths are very narrow, it is found that there is systematic velocity gradient in the molecular gas associated with the H II region. Both of 12CO and 13CO averaged spectra are non-gaussian, and there are obvious blue wings in the spectra. It is remarkable that the linewidths at the blueshifted region are broader than those of the rest of the cloud. The CO emission does match well with the dust emission.
        12.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We present the results of an rocket-borne observation of far-infrared [CII] line at 157.7 μm from the diffuse inter-stellar medium in the Ursa Major. We also introduce a part of results on the [CII] emission recently obtained by the IRTS, a liquid-helium cooled 15cm telescope onboard the Space Flyer Unit. From the rocket-borne observation we obtained the cooling rate of the diffuse HI gas due to the [CII] line emission, which is 1.3±0.2 × 10-26 ergss-1 H-1atom. We also observed appreciable [CII] emission from the molecular clouds, with average CII/CO intensity ratio of 420. The IRTS observation provided the [CII] line emission distribution over large area of the sky along great circles crossing the Galactic plane at I = 50° and I = 230°. We found two components in their intensity distributions, one concentrates on the Galactic plane and the another extends over at least 20° in Galactic latitude. We ascribe one component to the emission from the Galactic disk, and the another one to the emission from the local interstellar gas. The [CII] cooling rate of the latter component is 5.6 ± 2.2 ×10.
        13.
        1994.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We observed the molecular transitions of 12CO(1−0) 12CO(1−0) , 13CO(1−0) 13CO(1−0) , C18O(1−0) C18O(1−0) , CS(2-1), HCO+(1−0) HCO+(1−0) , and HCN(1-0) toward the high-latitude mole cular cloud MBM12. We derived total H2 H2 column densities for the two velocity components using the optically thin C18O C18O transition. Molecular abundances have been derived for the observed species at the core of this cloud, which appear to be less than an order of magnitude in fractional abundances relative to H2 H2 , compared to typical cold dark clouds.
        4,300원
        1 2