• 한국정보통신학회논문지
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• 제17권5호
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• pp.1055-1063
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• 2013

전자파 내성 및 전자파 장해 측정을 위한 표준 전자파 발생 장치 중 하나인 CTL cell에서 두 개의 입력 단자에 동일 신호와 역위상 신호 입력에 따른 다양한 전계와 자계 발생에 대해 살펴보았다. 기본 공진주파수 TE011이 2.20GHz인 CTL cell을 이용하여 우세 전계장과 우세 자계장 조건에서 입력 전력의 변화에 따른 전계 특성, 측정 위치에 따른 전계 특성, 주파수 변화에 따른 전계 특성을 측정하였고, 이를 이용하여 CTL cell의 측정 영역에서의 동작 특성과 공진주파수의 영향을 받지 않고 사용 가능한 주파수 대역을 살펴보았다.

• 대한전자공학회논문지
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• 제26권8호
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• pp.1145-1151
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• 1989

New method to calculate the characteristics of the dominant and higher order modes of waveguide latching phase shifters are presented. Due to the tensor permeability, E and H fields inside the ferrite are expanded in terms of the LSE and LSM eigenmodes of the dielectric-slab-loaded waveguide. The equivalent coupled transmission line equations on the transverse plane are derived to obtain the dispersion characteristics and the E and H field distributions. Numerical results at X-band are compared with those published previously. The derived field distributions can be used to suppress the higher order modes of the latching phase shifters, so that the phase shift from the dominant mode only contributes the performance of the phase shifters.

• The Korean Journal of Ecology
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• 제8권3호
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• pp.171-176
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• 1985

The structure of natural vegetation and soil condition in bog area of Woopo, Changnyeung, South Korea were observed. The vegetations in the investigated area could be classified into two groups; a typical bog vegetation with dominant species of Eleocharis mamillats, Acorus calamus and Persicaria hostatosagittata and the transitional vegetation of three neighboring areas. Interspecific correlation in the investigated area was very close. In the typical bog vegetatiion regions (region II, III, V, VI, VII, VIII and X) soil pH, field moisture capacity, available P content and exchangeable K were moderate. But, In the transitiional area I, with the highest humus content, field moisture capacity and exchangeable K Salix gracilistyla was dominant. In the region IV with the lowest humus and a ailable P content and with high soil pH Geophyta was a major component species. Also Acorus region IX with the lowest content of exchangeable K Therophyta was dominant and plant species was diverse due to weak water influence. The vegetation structure of the region IX was most different from that of the whole vegetation.

• 한국잡초학회지
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• 제17권3호
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• pp.262-268
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• 1997

경북지역 벼재배지에서 잡초분포현황을 조사하여 잡초방제의 기초자료로 활용코자 조사한 결과는 다음과 같다. 1. 생활사별 잡초 분포에 있어서 일년생이 56.5%로서 다년생 43.5% 보다 많았으며 형태적 분포는 화본과 25.2%, 사초과 12.3%, 광엽잡초 62.5%로 분포하였으며 화본과 잡초의 발생이 1971년, 1981년보다 증가하는 경향이었다. 2. 지대별 잡초 분포에서 평야지, 중간지, 냉조풍지에서는 피, 벗풀, 올방개, 물달개비가 우점초종이었으며 답종류별로는 보통답과 습답은 우점초종이 서로 비슷하게 발생하였으나 사질답에서는 잡초 발생 양상이 다르게 나타났다. 3. 손이앙답과 건답직파에서는 피의 우점이 가장 높았으나 기계이앙묘에서는 벗풀, 여뀌바늘 등이 우점잡초였고 이앙기별로는 이앙기가 늦어질수록 피의 발생이 많았다. 4. 경북지역의 주요 우점잡초는 피, 벗풀, 여뀌바늘, 올방개, 물달개비 순으로 나타났다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.273-278
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• 2007

2-D MT surveys at the Century mine in Australia have been performed with very far remote reference in Esashi, Japan as well as Gregory Downs, which are roughly 6400 km and 80 km apart from the field site, respectively. Long period pulsations observed in this survey generally showed dominant $H_x$ polarization than $H_y$; $H_x$ component is more than 3 times stronger than $H_y$ component. Polarity reversal in magnetic field pointing east ($H_y$ component) has also been observed in long period pulsations, while $H_x$ component remain coherent between the hemispheres. Though $H_x$ component shows relatively good coherency than $H_y$ component between the hemispheres at frequencies lower than 0.01 Hz, it seems rather too far to be used as a remote reference for ordinary MT frequency band.

• 한국초지조사료학회지
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• 제18권3호
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• pp.259-266
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• 1998

A field experiment was carried out to determine the effects of mechanical and chemical drying agents at mowing on the field drying rate and hay quality of orchardgrass dominant pasture plants. The mower conditioner /chemical drying agent ($K_2CO_3$ 2% conditioning, $K_2CO_3$ 2% + conditioning and control) were treated at different harvest stages (late boot, heading and bloom stage) for hastening hay manufacture in 1996. After field dry, four square bales were made by hay baler, and the visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rate of pasture plants was higher with delayed stage of harvest, and mechanical and mechanical + chemical, but chemical alone was very low. In mower conditioning, the duration of field dry was shortened by 0.5 to 1 day compared with $K_2CO_3$ and 1.5 to 2 days compared with control. The dry matter loss of hay was reduced by late harvest and mechanical, and mechanical + chemical, but the score by chemical alone was very low. The visual score (leafiness, green color, odor and softness) of hay after storage was high in mechanical and mechanical + chemical, but the score by chemical alone was very low. Nutritive value (ADF, NDF, digestibility, and relative feed value) of hay was also high with treatment of mechanical and mechanical + chemical, but the quality by chemical alone was similar compared with control. The quality of hay was very low when harvested at bloom stage. In conclusion, mower conditioning can enhance the field drying rate of orchardgrass dominant pasture plants, however the drying efficiency of chemical drying agent was very low. Harvesting at early heading to heading stage was recommened for manufacture of high quality hay.

• Journal of Magnetics
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• 제5권3호
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• pp.90-98
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• 2000

The change in the magnetic properties of a spin-valve multilayer with the structure IrMn (9 m)/CoFe (4 nm)/Cu (2.6 nm)/CoFe (2 nm)/NiEe (6 nm) is investigated as a function of the size and the aspect ratio. At a fixed aspect ratio (the length/width ratio) of 2, the magnetostatic interactions begin to affect the magnetic properties substantially at a spin-valve length of 5 $\mum$, and, at a length of 1 $\mum$, they become even more dominant. In the case of a fixed multilayer size (2.4 $\mum$) which is indicated by the sum of the length and the width, magnetization change occurs by continuous spin-reversal and M-H loops are characterized by no or very small hysteresis at aspect ratios smaller than unity, At aspect ratios greater than unity, magnetization change occurs by spin-flip resulting in squared hysteresis loops. A very large changes in the coercivity and the bias field is observed, and these results are explained by two separate contributions to the total magnetostatic interactions: the coercivity by the self-demagnetizing field and the bias field by the interlayer magnetostatic interaction field.

• 한국결정성장학회지
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• 제12권4호
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• pp.210-214
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• 2002

$450^{\circ}C$ 이하에서 Cu를 이용한 전계 유도 방향성 결정화 공정을 통해 비정질 실리콘의 결정화 거동을 고찰하였다. 열처리와 동시에 전계를 인가하여 Cu가 증착된 패턴의 외부에서 Cu가 존재하지 않는 비정질 실리콘의 영역으로 측면 결정화를 유도하였다. 특히, Cu가 존재하지 않는 영역의 측면결정화는 (-) 전극 쪽에서 (+) 전극 쪽으로 방향성을 가지고 결정화가 진행되었다. 이러한 현상은 Cu와 Si가 반응 할 때, 주확산 종이 금속(Cu)이기 때문에 가능하다고 판단되었다. 또한, FALC 공정을 이용한 $350^{\circ}C$의 온도에서 결정화된 영역 내에 커다란 dendrites 형태의 가지가 형성되었고 전계 방향에 따른 측면 결정화가 진행되었음을 확인하였다. 결론적으로 $350^{\circ}C$의 매우 낮은 온도에서 30 V/cm의 전계 인가를 통해 12$\mu$m/h의 결정화 속도로 결정화가 가능함을 확인하였다.

• 천문학회보
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• 제36권2호
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• pp.108.2-108.2
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• 2011

We investigate decaying magnetohydrodynamic (MHD) turbulence by including the effects of expansion and collapse of the background medium. The problem has two time scales, the eddy turn-over time($t_{eddy}$) and the expansion/collapse time scale(${\tau}_H$). The turbulence is expected to behave differently in two regimes of $t_{eddy}$ < ${\tau}_H$ and $t_{eddy}$ > ${\tau}_H$. For instance, for $t_{eddy}$ < ${\tau}_H$, the turbulence would decay more or less as in a static medium. On the other hand, for $t_{eddy}$ > ${\tau}_H$, the effects of expansion and collapse would be dominant. We examine the properties of turbulence in the regimes of $t_{eddy}$ < ${\tau}_H$ and $t_{eddy}$ > ${\tau}_H$. Based on it, we derive a scaling for the time evolution of flow velocity and magnetic field.

• 환경위생공학
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• 제5권1호
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• pp.54-62
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• 1990

충청북도 일원에서 1976년부터 1981년사이에 산불이 발생한 산화적지와 그에 인접한 비산화지의 식생과 토양성분을 조사하여, 산화 후의 식생회복과 토양성분과의 관계를 분석한 결과는 다음과 같다. 1. 79-B의 우점종 순위가 억새-산거울-싸리의 순으로 비산화지와 같게 나타나 산화 후 2년째 회복되었고, 그 후 산화적지에서 싸리가 점차 우점종으로 발달하여 산화 후 5년이 지난 76-B의 우점종 순위가 싸리-산거울-억새의 순이었다. 2. 생활형 조성은 산화 후 2년째부터 조사지소에 따라 H-e-$D_1-R_5$ 또는 Ph-e-$D_1-R_5$로 산화적지와 비산화지가 같게 되어, 산화 후 2년째에 산화적지의 생활형이 회복되었다. 3. 천이도는 81-B의 DS=423, 81-U의 DS=524로 산화적지가 낮았으나, 산화 후 2년째인 79-B의 DS=510, 79-U의 DS=520으로 거의 같았고, 산화 후 3년째부터는 산화적지가 비산화지보다 점차 높게 나타나 산화적지는 비산화지보다 천이가 빠르게 진행됨을 알 수 있다. 4. Shannon-Wiener function, Morishita's index 및 Simpson's index 등 종 다양성의 분석 결과에 의하면, 산화 당년에는 복잡한 군집이었으나 산화 후 2~3년째에 비산화지와 같은 단순한 군집으로 회복되었다. 또한 Evenness index의 분석 결과, 산화 당년에 식물종수가 비산화지보다 많았으나 산화 후 2년째부터 비산화지와 같은 종수가 되었다. 6. 산화적지의 식생은 산화 후 2~3년째에 비산화지의 식생과 거의 같게 회복되었고, 토양성분도 2~3년째에 회복되었다. 따라서, 산화 후 식생회복 과정과 토양성분의 변화사이에는 밀접한 관련이 있었다.