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        검색결과 127

        25.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We estimate the fractal dimension of the ρ Ophiuchus Molecular Cloud Complex, associated with star forming regions. We selected a cube (v, l, b) database, obtained with J = 1−0 transition lines of 12CO and 13CO at a resolution of 22′′ using a multibeam receiver system on the 14-m telescope of the Five College Radio Astronomy Observatory. Using a code developed within IRAF, we identified slice-clouds with two threshold temperatures to estimate the fractal dimension. With threshold temperatures of 2.25 K (3σ) and 3.75 K (5σ), the fractal dimension of the target cloud is estimated to be D = 1.52–1.54, where P / AD/2 , which is larger than previous results. We suggest that the sampling rate (spatial resolution) of observed data must be an important parameter when estimating the fractal dimension, and that narrower or wider dispersion around an arbitrary fit line and the intercepts at NP = 100 should be checked whether they relate to rms noise level or characteristic structure of the target cloud. This issue could be investigated by analysing several high resolution databases with different quality (low or moderate sensitivity).
        4,000원
        34.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 산국 생균제가 비육후기 거세한우의 성장율과 육질에 미치는 효과를 조사하기 실시하였다. 거세한우 15두(565±17kg)를 시험구별 개시체중이 유사하도록 산국 생균제 무첨가구(CON), 농후사료의 0.2% 첨가구(LCB) 및 0.4% 첨가구(HCB)에 각 5두씩을 배치하고 150일간 사양시험을 실시하였다. 농후사료와 조사료를 8:2의 비율로 설정하고 생체중의 약 2.5%를 오전(8시)과 오후(5시)로 나누어 급여하였다. 미네랄 블록과 음수는 자유로이 섭취할 수 있도록 하였다. 사양시험 종료 후에는 모든 공시동물은 도축하여 도체특성을 조사하고 등심육을 채취하여 육질분석에 이용하였다. 개시체중과 종료체중은 처리구간 차이가 없었으나, 일당증체량, 사료섭취량 및 사료효율은 산국 생균제를 급여한 모든 시험구에서 대조구에 비해 개선되었다(p<0.05). 분 중 황화수소와 암모니아 가스는 시험구간 차이가 없었다. 신선육 관능평가에서 등심육의 육색은 산국 생균제를 급여한 시험구가 개선되었으나(p<0.05), 등심육의 물리화학적 특성과 기타 신선육 관능평가는 시험구간 차이가 없었다. 등심육의 지방산 조성은 산국 생균제를 급여한 시험구에서 C14:0과 C18:0 함량이 증가하였으며(p<0.05), HCB 시험구에서 C18:2n-6와 polyunsaturated fatty acid 함량은 HCB 시험구에서 가장 높게 나타났다(p<0.05). 따라서 비육후기 거세한우에 산국 생균제를 0.4% 수준으로 급여하는 것은 사료효율 개선, 육색 및 등심육 지방산 품질개선에 유리할 것으로 사료된다.
        4,000원
        36.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 미생물 첨가가 느타리버섯 폐배지의 영양소 함량, 발효특성 및 미생물상에 미치는 영향을 조사하기 위해 수행하였다. 시험은 느타리버섯 폐배지에 미생물 무첨가구(CON), 고초균 첨가구 (Bacillus subtilis 2⨯1010 cfu/g; BS), 유산균 첨가구(Lactobacillus plantarum 2⨯1010 cfu/g; LP) 및 혼합균 첨가구(Bacillus subtilis : Lactobacillus plantarum = 1:1; BL)로 4 시험구를 설정하고 6일간 발효시켰다. 발효 직후 0, 1, 2, 4 및 6일에 시료를 채취하여 분석에 이용하였다. 발효 6일후 조단백질과 조지방 함량은 BS구에서 가장 높았다(P<0.05). NDF 함량은 LP구와 BL구에서, ADF 함량은 미생물을 첨가한 모든 시험구에서 높은(P<0.05) 반면, in vitro 건물소화율은 CON구가 높았다 (P<0.05). Lactate와 propionate 함량은 CON구와 BS구가 타 시험구에 비해 높았다(P<0.05). 한편 발효 0일에 유산균 함량은 BS구와 LP구에서 높았으며(P<0.05), 발효 1일에 유산균 함량은 LP구에서, 고초균 함량은 BL구에서 각각 높았다(P<0.05). 발효 2일에 lactate와 propionate 함량은 LP구와 BL구에서 타 시험구에 비해 높았다(P<0.05). 이상에서와 같이 BS 첨가는 발효과정 중 유기산 생성량 개선에는 유리하나 건물소화율에는 부정적인 영향을 미칠 것으로 사료된다.
        4,000원
        37.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the ‘background’ task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using ‘background’ task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.
        4,000원
        39.
        2012.06 구독 인증기관·개인회원 무료
        The reactive oxygen species (ROS) generated during the somatic cell transfer nuclear (SCNT) procedures may cause the mitochondrial dysfunction and DNA damage, which may result in restricts the reprogramming of SCNT embryos and play a key direct role in apoptosis. The present study was conducted to investigate the effect of antioxidant treatment during the SCNT procedures on the inhibition of mitochondria and DNA damages in bovine SCNT embryos. The reconstituted oocytes were treated with antioxidants of 25 μM β-mercaptoethanol (β-ME) or 50 μM vitamin C (Vit. C) during the SCNT procedures. In vitro fertilization (IVF) was performed for controls. Mitochondrial morphology and membrane potential (ΔΨ) were evaluated by staining the embryos with MitoTracker Red or JC-1. Apoptosis was analyzed by Caspase-3 activity assay and TUNEL assay, and DNA fragmentation was measured by comet assay at the zygote stage. Mitochondrial morphology of non-treated SCNT embryos was diffused within cytoplasm without forming clumps, while the IVF embryos and antioxidant treated SCNT embryos were formed clumps. The ΔΨ of β-ME (1.3±0.1, red/green) and Vit. C-treated (1.4±0.2, red/green) SCNT embryos were significantly higher (p<0.05) than that of non-treated SCNT embryos (0.9±0.1, red/ green), which similar to that of IVF embryos (1.3±0.1, red/green). Caspase-3 activity was not difference among the groups. TUNEL assay also revealed that little apoptosis was occurred in SCNT embryos as well as IVF embryos regardless of antioxidant treatment. Comet tail lengths of β-ME and Vit. C-treated SCNT embryos (337.8±23.5 μm and 318.7 ±27.0 μm, respectively) were shorter than that of non-treated SCNT embryos (397.4± 21.4 μm) and similar to IVF embryos (323.3±10.6 μm). These results suggest that antioxidant treatment during SCNT procedures can inhibit the mitochondrial and DNA damages of bovine SCNT embryos.
        40.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the silver nanoparticles have been synthesized by electrical explosion of wire in three liquid mediums: deionized water (DIW), polyvinylpyrrolidone (PVP) and sodium dodecyl benzene sulfonate (SDBS) solutions. Absorption in the UV-visible region of these suspensions was measured in the range of 300-800 nm. A surface plasmon peak was observed at ~400 nm in all suspensions in measured wavelength range. Particle size was analyzed by transmission electron microscope. It showed that the particles had nearly spherical shape in all samples. The average particle sizes prepared in DIW, PVP and SDBS solution were 37, 31 and 27 nm, respectively. Stability of the suspensions was estimated by multiple light scattering method. The presence of PVP and SDBS surfactants in the exploding medium resulted in enhanced stability of the silver suspensions.
        4,000원
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