• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.202-202
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• 2013

유도결합 플라즈마 방전 시 사용되는 L형 임피던스 정합기(impedance matcher)의 경우 일반적으로 직렬 및 병렬 콘데서가 연결되어있으며, 임피던스 정합조건이 되었을때 전원과 안테나 사이에 있는 임피던스 정합기의 소자값이 특정 값을 가지게 된다. 유도결합 플라즈마를 진단하기 위한 여러 방법들이 연구되어 왔지만, 이러한 임피던스 정합조건과 플라즈마 내부 변수들의 상관 관계에 대한 연구는 보고된 바 없다. 본 연구에서는 유도결합 플라즈마의 임피던스 정합조건과 유도결합 플라즈마의 변압기 회로모델를 이용하여 플라즈마 저항 및 플라즈마 인덕턴스를 구하기 위한 관계식을 도출하고 임피던스 정합기의 직렬 및 병렬 콘덴서 용량값 측정하여 플라즈마 저항 및 플라즈마 인덕턴스값을 계산하였다. 결과 검증을 위해 다양한 압력 및 전력 조건에서 부유랑뮤어 탐침법을 이용하여 플라즈마 밀도를 측정해 비교해 보았으며, 두 결과의 경향성은 잘 일치함을 확인하였다.

• KDI Journal of Economic Policy
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• v.11 no.2
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• pp.89-97
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• 1989

본고(本稿)의 목적(目的)은 현재 우리나라 신규(新規)아파트분양시장(分讓市場)에서 실시되고 있는 가격규제(價格規制), 특히 최고가격제(最高價格制) 채권입찰제(債券入札制) 아래서 수요(需要)의 가격탄성치(價格彈性値)를 계측(計測)해 보는 데 있다. 계측결과(計測結果) 중 흥미로운 것은, 첫째 분양가를 기준으로 계측한 평형별(坪型別) 가격탄성치(價格彈性値)가 대부분이고 2.5~3.5 사이의 수치(數値)를 일관성있게 보여 신규아파트 분양수요가 가격에 대단히 탄력적이고, 둘째 평형별(坪型別) 군별(群別) 신규(新規)아파트 수요(需要)의 가격탄성치(價格彈性値)는 2군(群)이 1군(群)보다 절대값에서 작은 수치를 보여주었으며, 셋째 아파트 가격이 상승함에 따라 절대값으로 표시한 가격탄성치(價格彈性値)가 처음에는 커져다가 점점 작아지는 것으로 보아 수요곡선이 완만한 L형을 나타낼 것이라는 점이다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.560-563
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• 2008

A condensed model is proposed for the simulation of forming of sandwich sheet with pyramid core. A corresponding finite element analysis for L-type bending is carried out to prove the accuracy and the effectiveness. Simulation results are compared with those of experiment. Deformation shape and post-buckling behavior by simulation are in good agreement with those of experiment for the considerable range of deformation. From the comparison of force-displacement curve, it is shown that the proposed model shows good prediction of the forming force compared to the experiment. Thus, the effectiveness of the proposed method is sufficiently demonstrated.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.2
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• pp.176-183
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• 1999

This paper is aimed to investigate behaviour of vortex in 2-D step cavity with high Reynolds numbers$(3.2{\times}10^{3},\;10^{4},\;3{\times}10^{4},\;5{\times}10^{4}\;and\;7{\times}10^{4})$. The SOLA algorithm which is MAC type was adopted to solution method computing the flow field on irregular grid. In case of $Re=7{\times}10^{4}$ flow behavior is steady bu periodic unsteady sinusoidal fluctuation of local velocity and kinetic energy is found for $Re=10^{4}$ Continuous movements of small eddies in the secondary flow regions are discov-ered for $3{\times}10^{4}$ Generation of eddies and their active migrating behavior are detected over $Re=5{\times}10^{4}$ resulting in complete unsteady and non-linear flow characteristics Furthermore a typhoon-like vortex(TLV) appears intermittently and rotates along the separation regions and boundary layers.

• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.447-455
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• 2013

In this study, reinforced concrete slabs with steps were experimentally studied to analyze their structural performance and to suggest reinforcing details in the step. Because the stepped slabs may behave very poorly in terms of bending strength, stiffness, deflection, cracking, etc., the study is aimed to suggest proper reinforcing details such that the same bending strength is obtained as that without steps. The bending strengths of 12 test specimens with a variety of different reinforcing detail types or other parameters were compared with each other. The specimen without any additional reinforcement in the step had a very low bending strength and significant damage, and the specimens with diagonal reinforcements in the step showed substantial early cracks, experienced hinging of the step, and had a substantial loss of the bending strength. In contrast, the specimens with a combination of U-bars, reversed U-bars, L-bars, and reversed L-bars performed very well and almost reached to 100% of the slab bending strength. The U-bars and reversed U-bars were effective in controling the diagonal cracks, while the L-bars and reversed L-bars were effective in preventing from yielding of slab reinforcement near the step.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1101-1110
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• 2011

This paper presents a printed, wideband folded monopole antenna for laptop and tablet computer applications. The proposed antenna is designed to cover bandwidth(2.3~10.6 GHz) of Bluetooth, WiMAX, and UWB system by using the printed folded monopole antenna having asymmetrical line width coupling with a parasitic inverted- L element. Also, wireless LAN band(5.15~5.85 GHz) which interferes with UWB system is rejected by inserting half-wavelength open stub in the folded monopole antenna. -10 dB bandwidth of the fabricated wideband antenna is 2.27~10.6 GHz (4.7:1) and -10 dB band-rejected bandwidth is measured as 700 MHz(5.15~5.85 GHz, 12.72 %). The gain and efficiency of the antenna except for the rejected band are higher than 3.93 dBi and 91.89 % and are measured as -2 dBi and 14.65 % at 5.5 GHz which is band-rejected frequency. The size of the antenna is suitable to install for small space of tablet and laptop computers as 12.75(1 ${\lambda}$/10)${\times}$12(1 ${\lambda}$/11) $mm^2$(${\lambda}$ is free space wavelength at 2.3 GHz). Therefore, we verified that the designed antenna is appropriate for wideband antenna of tablet and laptop PC applications.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.666-670
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• 2001

Levofloxacin is L-form stereoisomer of ofloxacin. It has better antibacterial activity than D-oflxacin. In this study, levofloxacin was produced enantioselectively by using high density culture of recombinant E. coli containing a foreign esterase gene. Final cell concentration was 89 g/L at the end of fed-batch culture and the cells were used for levofloxacin production after IPTG induction at the optimized condition. For the immobilization of recombinant E. coli. 1.5% sodium alginate showed the best result to maintain enzyme activity and enantioselectivity.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1802-1806
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• 2009

최근 들어 국내외에서는 하천환경 및 생태서식처 기능을 갖는 자연형 하천으로의 복원에 대한 연구가 활발히 진행되고 있다. 이러한 하천복원의 범주에서 하천 내 설치되는 수공구조물에 대한 중요성이 많이 언급 되고 있는데 그 중 대표적인 것으로 수제를 들 수 있다. 하천 내 설치하는 수제(groyne)는 제방보호 및 유로변경의 목적으로 하천내에 시공되는 구조물 중의 하나로서 하천복원과정에 있어 필수불가결한 구조물 중의 하나로 인식되고 있다. 근래에 들어 경제성 및 환경성을 갖는 수제에 대한 연구로 변형수제에 대한 연구들이 진행 되고 있는데 변형수제의 대표적인 형상으로는 L형, T형 수제 및 굴절, 열쇠형 수제 등이 있다. 각각의 수제들은 그 형상에 따라 수제주변에서 국부적인 흐름구조가 다르게 발생하게 된다. 이러한 수제들은 수제 고유의 형태에 대한 흐름특성 연구들이 주로 이루어지고 있는 반면에 수제의 투영길이에 대한비교는 수행되지 않았다. 즉 동일한 수제길이를 갖더라도 설치각이나 형태에 따라 투영면적에 대한 유수단면적의 변화가 발생하게 된다. 본 연구에서는 그림과 같이 상향 또는 하향굴절수제를 대상으로 팔길이(AL)의 변화를 주었으며, 팔길이 변화로 인해 발생되는 투영길이(L')와 동일한 길이를 갖는 연직수제를 제작하여 흐름특성을 관측하고 비교하여 보았다. 수제는 군집 형태로 건설되는 것이 일반적이나 여러 가지 형태의 조합으로 건설되기도 하는데 이러한 투영길이에 대한 비교는 수제설계 시 기초자료로 활용될 수 있을 것이다.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.111-117
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• 2006

Cardiac chambers serve as mechanosensory systems during the haemodynamic or mechanical disturbances. To examine a possible role of fluid pressure (FP) in the regulatien of atrial $Ca^{2+}$ signaling we investigated the effect of FP on L-type $Ca^{2+}$ current $(I_{Ca})$ in rat ventricular myocytes using whole-cell patch-clamp technique. FP $(\sim40cm\;H_2O)$ was applied to whole area of single myocytes with electronically controlled micro-jet system. FP suppressed the magnitude of peak $I_{Ca}$ by $\cong25\%$ at 0 mV without changing voltage dependence of the current-voltage relationship. FP significantly accelerated slow component in inactivation of $I_{Ca}$, but not its fast component. Analysis of steady-state inactivation curve revealed a reduction of the number of $Ca^{2+}$ channels available for activity in the presence of FP. Dialysis of myocytes with high concentration of immobile $Ca^{2+}$ buffer partially attenuated the FP-induced suppression of $I_{Ca}$. In addition, the intracellular $Ca^{2+}$ buttering abolished the FP-induced acceleration of slow component in $I_{Ca}$ inactivation. These results indicate that FP sup-presses $Ca^{2+}$ currents, in part, by increasing cytosolic $Ca^{2+}$ concentration.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.137-147
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• 2012

This paper describes an experimental study on the mechanical characteristic and behavior of a structure that has a joint between the reinforced concrete (RC) member and steel plate concrete (SC) member. An out-of-plane flexural test on an L-type test specimen and in-plane shear test on an I-type test specimen were carried out by means of repeated cyclic loading until their failure. Based on the results, the former showed pull-out failure mode of anchored vertical bars while the latter exhibited flexural failure mode of the basement member. These results reveal that the maximum capacity of the specimens is 96% and 82%, respectively, compared with the theoretical value.