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한경남,남기봉,정충훈 한국어류학회 2001 韓國魚類學會誌 Vol.13 No.1
The early developmental stages, growth and morphological changes of the Korean bullhead, Pseudobagrus fulvidraco, were studied from a series of reared specimens. Details of the early developmental stages are illustrated with special reference to morphological transformations. Egg and sperm of Korean bullhead were obtained from mature adults under hormonal treatment, fertilized artificially, and incubated in the aquarium. The incubation period of fertilized eggs was 55 to 66 hours at a temperature of 24.9±0.34℃. Larvae were fed successively with Artemia salina and Daphnia magna for 2 to 15 days and artificial food after 20 days. Fertilized eggs were adhesive and spherical with a diameter of 2.04㎜(n=100). The mean total length of newly hatched larvae was about 4.92±0.33㎜. Mouth opening occurred on one-day-old yolk-sac larvae, and initial feeding was observed on the third day after hatching. The morphological transitions from larvae to juvenile and juvenile to young stages occurred when the fish reached about 17㎜ in total length(about 13 days after hatching) and about 32㎜ in total length(about 30 days after hatching), respectively. Many changes in proportion of body parts to total length were observed at about 7∼8㎜ and 30∼32㎜, corresponding to the transformations from larvae to juvenile and from juvenile to young, respectively. In comparing relative growth of each body part against total length, those characteristics related to head parts showed positive growth in the pre-larval stages, while those concerning mobile abilities showed positive growth in the post-larval stage.
메타 구조 Broadside Coupled 나선형 공진기를 이용한 저위상 잡음 전압 제어 발진기
한경남(Kyoungnam Han),서철현(Chulhun Seo) 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.9
본 논문에서는 메타 구조 Broadside Coupled 나선형 공진기(BC-DSRs)를 이용하여 전압 제어 발진기의 위상잡음 특성을 줄이기 위한 새로운 구조를 제안하였다. 이러한 특성 실현을 위하여 연속된 나선형 구조를 신호면과 그라운드 면에 각각 적용하였다. 일반적인 전압 제어 발진기와 비교하였을 때, 본 논문에서 제안한 VCO는 더 큰 결합 계수를 가지며, 이로 인하여 얻을 수 있는 더 높은 Q값을 통하여 전압 제어 발진기의 위상 잡음을 줄일 수 있다. 1.8 V의 공급 전력을 갖는 전압 제어 발진기는 주파수 조절 범위, 5.749~5.853 ㎓에서 -121~-117.16 ㏈c/㎐ @ 100 ㎑의 위상 잡음 특성을 갖는다. 또한 전압 제어 발진기의 Figure Of Merit(FOM)은 동일한 주파수 조절 범위에서 -198.45~-194.77 ㏈c/㎐ @ 100 ㎑의 특성을 보였다. In this paper, a novel voltage-controlled oscillator(VCO) using the metamaterial broadside coupled spiral resonators (BC-DSRs) is presented for reducing the phase noise. For reducing of the phase noise, the series spiral structures have been applied for the signal plane and ground plane at each in order to have the large coupling. Compared with the conventional VCO, the proposed VCO has the larger coupling coefficient constant, which makes a higher Q-factor and has reduced the phase noise of the VCO. The proposed VCO has the phase noise of -121~-117.16 ㏈c/㎐ at 100 ㎑ in the tuning range, 5.749~5.853 ㎓. The figure of merit(FOM) of this VCO is -198.45~-194.77 ㏈c/㎐ at 100 ㎑ in the same tuning range, respectively.