http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Semi-lumped Balun Transformer using Coupled LC Resonators
Park, Jongcheol,Yoon, Minkyu,Park, Jae Yeong The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
This paper presents a semi-lumped balun transformer using conventional PCB process and its design theory and geometry for the maximally flat response and wide bandwidth using magnetically coupled LC resonators. The proposed balun is comprised of two pairs of coupled resonators which share one among three LC resonators. It provides an identical magnitude and phase difference of 180° between two balanced ports with DC isolation and an impedance transformation characteristic. Theoretical design and analysis were performed to optimize the inductance and capacitance values of proposed balun device for obtaining the wide bandwidth and maximally flat response in its pass-band. Three balun transformers with a center frequency of 500 MHz were demonstrated for proving the concept of design proposed. They were fabricated by using lumped chip capacitors and planar inductors embedded into a conventional 4-layered PCB substrate. They exhibited a maximum magnitude difference of 0.8 dB and phase difference within 2.4 degrees.
Semi-lumped Balun Transformer using Coupled LC Resonators
Jongcheol Park,Minkyu Yoon,Jae Yeong Park 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
This paper presents a semi-lumped balun transformer using conventional PCB process and its design theory and geometry for the maximally flat response and wide bandwidth using magnetically coupled LC resonators. The proposed balun is comprised of two pairs of coupled resonators which share one among three LC resonators. It provides an identical magnitude and phase difference of 180° between two balanced ports with DC isolation and an impedance transformation characteristic. Theoretical design and analysis were performed to optimize the inductance and capacitance values of proposed balun device for obtaining the wide bandwidth and maximally flat response in its pass-band. Three balun transformers with a center frequency of 500 MHz were demonstrated for proving the concept of design proposed. They were fabricated by using lumped chip capacitors and planar inductors embedded into a conventional 4-layered PCB substrate. They exhibited a maximum magnitude difference of 0.8 dB and phase difference within 2.4 degrees.
연약지반상 압성토의 최적단면 및 측구위치 결정을 위한 해석적 연구
박종철(Jongcheol Park),장용채(Yongchai Chang),백인철(Incheol Baek),정동환(Donghwan Jung) 한국지반신소재학회 2015 한국지반신소재학회 논문집 Vol.14 No.1
압성토공법은 성토체의 안정성을 높이기 위하여 성토체 측면에 일정한 폭과 높이로 흙을 쌓은 공법을 말한다. 본 연구는 실제 도로현장에서 전단파괴가 발생되어 복구방법으로 압성토공법을 적용한 시공사례를 분석한 것이다. 본 연구는 수치해석을 실시하여 효율적인 압성토 단면을 제시하고자 한다. 수치해석결과 효율적인 압성토 단면은 압성토 폭 : 제체 높이의 2배(2H), 압성토 높이 : 제체높이의 1/3(H/3) 이다. 또한, 압성토체를 가로지르는 측구를 설치할 경우, 본성토체로부터 적절한 이격거리를 제시함으로서 효과적인 횡단측구의 범위를 제시하였다. The counter weight filling is a technology to accumulate soils on the side of berm with a proper width and height for improving the stability of the embankment. This study aims to assess a feasibility of the counter weight filling in the construction of pavement roads for recovery of shear failure during the construction. An effective counter weight filling section was suggested using the numerical analysis. The results showed that the effective counter weight filling section is two-fold (x2) higher than the ratio of width in counter weight filling : embankment height and one third (1/3) to the ratio of height in counter weight filling : embankment height. Also a range of effective trench crossing the counter weight filling required when a trench crossing counter weight filling is installed was suggested by supplying a proper distance between the counter weight filling section and cross-sectional trench.
Park, HyungBin,Ko, ChungHo,Lee, SeungYoun,Kim, SangYong,Yang, JongCheol,Lee, KiCheol The Ecological Society of Korea 2019 Journal of Ecology and Environment Vol.43 No.2
Background: To exploit the ornamental and medicinal purposes of Lonicera harae Makino, L. subsessilis Rehder, L. praeflorens Batalin, and L. insularis Nakai, native to Korea, it is necessary to understand their seed ecology for propagation. In this study, we investigated the seed dormancy type and germination characteristics of seeds of the four Korean native Lonicera species. Results: The seeds of the four Lonicera species imbibed water readily, suggesting that the species do not have physical dormancy. Furthermore, the seeds exhibited underdeveloped embryos with only about 15-25% of the length of the seeds at dispersal. The embryos grew to the critical length with approximately 50-80% of the length of the seeds' development before radicle protrusion. Further, 94.4% and 61.1% of freshly matured seeds of L. insularis and L. harae germinated within 4 weeks after sowing at 15 ℃ and 20 ℃, respectively. Contrarily, L. praeflorens and L. subsessilis seeds did not germinate within 4 weeks under all temperature treatments. At 15 ℃, L. praeflorens seeds started to germinate from 5 weeks and the final germination rate was 51.1% at 13 weeks. At 15 ℃, L. subsessilis seeds started to germinate from 5 weeks after sowing and the final germination rate was 85.6% at 17 weeks after sowing. Embryo growth and germination of L. praeflorens and L. subsessilis occurred at a relatively high temperature (≥ 15 ℃). Conclusions: Overall, L. insularis seeds have only morphological dormancy. The seeds of L. harae have approximately 60% and 40% of morphological dormancy and morphophysiological dormancy, respectively. Contrarily, L. praeflorens and L. subsessilis exhibited non-deep simple-type morphophysiological dormancy that requires relatively high temperature (≥ 15 ℃) for embryo growth and dormancy breaking. The optimum temperature for the germination of seeds of L. insularis, L. harae, L. praeflorens, and L. subsessilis was 15 ℃, 20 ℃, 15 ℃, and 20 ℃, respectively. There was interspecific variation in seed dormancy and germination patterns in the four Lonicera species. The difference in these characteristics within the four Lonicera species could be useful for understanding the seed ecophysiological mechanisms of Lonicera species.