• Structural Engineering and Mechanics
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• 제87권1호
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• pp.95-106
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• 2023

This paper investigates the dynamic response of a functionally graded material (FGM) coated half-plane excited by distributed time harmonic loading. Three types of typical distributed surface loads, including uniform load, Hertz load, and square-root singular load, are considered. The mass density and elastic modulus of the FGM coating are supposed to be described by the exponential function. The material damping is modelled by a linearly hysteretic damping which is expressed by a complex modulus in the time harmonic motion. Using Fourier integral transform technique and numerical integral method, the effects of the excitation frequency, gradient index, damping, and load type on the dynamic stresses and displacements are discussed.

• 분석과학
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• 제22권5호
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• pp.355-359
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• 2009

An enzyme electrode bound by rubber solution was newly constructed and the test of its practicability were carried out. The binder of carbon powder was styrene-butadiene rubber dissolved in toluene and enzyme source was ground tissue of cabbage root. Volatilization of the solvent made the electrode material possess a mechanical robustness and a fast signal appearance. The electrode showed electrochemically irreversible characteristics and a powerful catalytic power (detection limit=$5.0{\times}10^{-5}M$, S/N=2). The double reciprocal plot of signal current and substrate concentration was ideally linear and the symmetry factor and exchange current density of the electrode used in this work were 0.35 and $4.93{\times}10^{-5}Acm^{-2}$ respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1203-1206
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• 2005

Electron temperature and plasma density in coplanar alternating-current plasma display panels (AC-PDP's) have been experimentally investigated in accordance with discharge time by a micro-probe in this experiment. The resolution of a step mortor to move in micro-Langmuir probe is 10um.[1-3] The used gas in this experiment is He-Ne-Xe (4%) mixure gas. And sustain voltage is 320V which is above of firing voltage for degradation. The electron temperature and plasma density can be obtained from current-voltage (I-V) characteristics of micro Langmuir probe, in which negative to positive bias voltage was applied to the probe. And Efficiency is calculated by formula related discharge power and light emission. Those experiments operated as various discharge time ($0{\sim}72$ Hours). As a result of this experiment, Electron Temperature was increased from 2eV to 5eV after discharge running time of 20 hours and saturates beyond 20 hours. The plasma density is inversely proportional to the square root of electron temperature. So the plasma density was decreased from $1.8{\times}10^{12}cm^{-3}$ to $8{\times}10^{11}cm^{-3}$ at above discharge running time. And the Efficiency was reduced to 70% at 60hours of discharge running time.

• 농업과학연구
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• 제2권1호
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• pp.125-130
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• 1975

묘삼(苗蔘)의 재배현황(栽培現況) 및 재식위치(栽植位置)에 따르는 생육(生育)의 차이(差異)와 형질상호간(形質相互間)의 관계(關係)를 구명(究明)하고져 이 조사연구(調査硏究)를 수행(遂行)하였던바 결과(結果)를 요약(要約)하면 다음과 같다. 1. 대부분(大部分)의 농가(農家)에서 지력증진(地力增進)을 위(爲)한 특별(特別)한 고려(考慮)는 거의 없었으며 시비(施肥)는 기비(基肥)로서 녹비(綠肥)만을 시용(施用)하고 있고 금비(金肥)의 시용(施用)은 전(全)혀 없었다. 2. 종자(種子)의 개량(改良)을 위(爲)한 노력(努力)은 전(全)혀 없었고 종자(種子)는 3년근(年根)의 인산(人蔘)에서 채종(採種)하고 있었으며 재식밀도(栽植密度)는 평균(平均) $1.8cm{\times}2cm$였다. 3. 묘삼(苗蔘)의 생육전반(生育全般)에 걸쳐 재배포장(栽培圃場)(농가(農家)) 간(間)에 고도(高度)의 유의차(有意差)가 인정(認定)되었으며 재배포장(栽培圃場)에 따라 변이정도(變異程度)가 가장 큰 형질(形質)은 근직경(根直徑)이었고 다음이 경태(莖太)였으며 변이정도(變異程度)가 가장 적었던 것은 근장(根長)이었다. 4. 근직경(根直徑)을 제외(除外)한 모든 형질(形質)의 발육(發育)은 전열(前列)에서 현저(顯著)한 저조(低調)를 보였고 근직경(根直徑)은 후례(後例)에서 가장 짧았다. 5. 경장(莖長)과는 어떠한 형질(形質)도 유의상관(有意相關)이 인정(認定)되지 않았으며 근직경(根直徑)과 경태(莖太), 엽폭(葉幅)과 경태(莖太) 엽폭(葉幅)과 엽장간(葉長間)에는 유의상관(有意相關)이 인정(認定)되었고 경장(莖長)과 근직경(根直徑), 경장(莖長)과 경태(莖太), 경장(莖長)과 근장간(根長間)에는 유의성(有意性)은 인정(認定)되지 않으나 부(負)의 상관(相關)을 보이고 있어 주목(注目)된다.

• 한국환경농학회지
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• 제20권2호
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• pp.86-92
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• 2001

벼논 오리농법에 있어서 오리 방사체계를 명확히 하기 위해 각 처리구를 4 a의 동일면적으로 구분하고, 방사 오리수를 각각 6수, 9수, 12수 및 15수씩으로 하는 4처리구를 설계하여 방사밀도에 따른 오리의 행동형 및 벼 생육과 수량반응에 미치는 영향에 대하여 검토하였던 바, 그 결과를 요약하면 다음과 같다. 오리 방사밀도에 따른 일중 12시간 동안의 행동변화에서 섭식 및 이동행동은 12수 방사구에서 가장 길었고, 노동행동에서도 다른 3처리구에 비해 12수 방사구에서 유의적으로 길게 나타났다(P<0.05). 반면 휴식행동은 12수 방사구에 비해 9수 및 15수 방사구에서 현저히 길게 나타났다(P<0.05). 방사오리가 가장 활발한 활동을 보이는 일중 6시간 동안의 이동 회수는 15수 방사구에서 가장 적었고 나머지 3처리구간에서는 거의 비슷한 수준을 보였다. 잠수회수는 9수 방사구에서 다른 3처리구에 비해 유의적으로 많았으며(P<0.01), 벼 포기 쪼는 회수도 9수 방사구에서 12수 및 15수 방사구에 비해 현저히 많았다(P<0.05). 그러나 오리가 쪼은 총 벼포기수에서는 방사밀도가 낮은 6수 및 9수 방사구에 비해 15수 방사구에서 유의적으로 많았다(P<0.01). 벼 초장은 오리 방사후 30일째부터 방사밀도가 높을 수록 짧아지는 경향을 보였고(P<0.05), 경수(莖數)는 방사밀도에 의해 대차없었다. 출수후 벼 생육변화에서 간장(稈長)은 방사밀도가 높은 12수 및 15수 방사구에서 짧았고(P<0.05), 수장(穗長)은 오리 방사밀도에 의해 대차없었다. 벼 지상부의 건물중량은 방사밀도가 높을 수록 낮은 값에 편중됨을 보인 반면, 지하부의 건물중량은 증가하는 경향을 나타냈다. 오리 방사밀도에 따른 벼 결주발생수은 15수 방사구에서 가장 많았고, 다음으로 6수, 9수 및 12수의 순으로 나타났다. 한편 수당(穗當) 영화수는 6수 및 9수 방사구에 비해 12수 및 15수 방사구에서 유의적으로 많았고(P<0.05), 등숙율은 다른 3처리구에 비해 15수 방사구에서 낮은 경향을 보였다. 10 a당 수량은 12수 방사구에서 726.5 kg으로 가장 높은 수량증가를 보였고, 다음으로 9수, 15수 및 6수 방사구의 순으로 나타났다.

• 한국환경복원기술학회지
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• 제5권6호
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• pp.24-29
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• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.

• 한국자원식물학회지
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• 제16권1호
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• pp.40-48
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• 2003

C. destructans는 인삼에서 가장 문제가 되고 있는 뿌리섞음병을 유발하는 매우 중요한 미생물이다. 현재까지 정상적인 인삼포장이나 폐포지에서도 이 병원균의 농도를 조사할 만한 방법이 없어 이를 쉽게 조사함으로서 인삼 예정지 관린시 도움을 줄 수 있는 새로운 방법이 절실이 요구되고 있다. 본 연구에서는 nested PCR이란 분자생물학적 방법을 이용하여 효과적으로 매우 낮은 농도의 C. destructans을 검출할 수 있는 방법을 개발하였다. 2개의 universal ITS primers(ITS5F와 ITS4R)을 사 용 하 여 Cylindrocarpon spp.의 rDNA로부터 ITS영역을 증폭하였다. 이어 C. destructans의 specific primer(Nest 1 과 Nest 2)을 사용하여 최적의 PCR조건으로 재증폭시켜 밴드를 확인하였다. 또한 이런 2번의 과정을 4개의 primer를 동시에 사용함으로서 한번에 확인할 수 있는 방법을 개발하였으며 이에 따른 PCR조건도 확립하였다. 따라서 본 방법에 의해서 인삼포장의 토양에서 채취된 매우 낮은 농도의 wild type C. destructans spore로부터 성공적으로 positive band을 확인함으로써 추후 인삼포장의 선정 및 4년생에서 6년까지(홍삼포) 재배기간등의 예측에 활용 될 것으로 생각된다.

• 동의생리병리학회지
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• 제29권4호
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• pp.322-329
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• 2015

Cirsium japonicum var. ussuriense are often used in treatment of human diseases such as hemorrhage, blood congestion and inflammation in Korea. However, there was not report on the anti-obesity efficacy of water extracts from different organs of C. japonicum var. ussuriense. Here, we investigated the antioxidant effects of water extracts of flowers, leaves and roots from C. japonicum var. ussuriense. Total polyphenol amounts of the flower extract showed higher than those of leaf and root extract. Flower extract also showed the high antioxidant activities such as DPPH radical scavenging activity and reducing power. We also investigated the anti-obesity effects of water extracts of flowers, leaves and roots from C. japonicum var. ussuriense in 3T3-L1 cells and high fat diet-induced obesity mice. The mice were divided into four groups [high fat diet (HFD) control, HFD + leaf extract, HFD + flower extract and root extract] and administered with each extract (200 mg/kg) for 12 weeks. The flower and leaf extract significantly suppressed the levels of oil red O and triglyceride content. The flower and leaf extract also significantly reduced the triglyceride, total cholesterol and lower density lipoprotein levels of plasma as well as body and abdominal fat weight. Furthermore, oral glucose tolerance in the flower and leaf extract groups were significantly ameliorated in comparison to the high fat diet group. Therefore, these results indicate that the flower and leaf extract could ameliorate obesity and attenuate blood glucose level in high fat diet-induced obesity mice. We conclude that this study may provide positive insights into water extracts of flowers and leaves from C. japonicum var. ussuriense as a functional food ingredient for treatment of obesity.

• 한국작물학회지
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• 제44권3호
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• pp.201-206
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• 1999

For the mass production of plug seedlings in cultivar ‘Dejima’ potato (Solanum tuberosum L.) the optimal apical cutting diameter for rooting and rapid multiplication of stem cuttings in hydroponics were determined. In addition, the best planting date was predicted to increase tuber yield of plug seedlings at fall cropping in Cheju-Do, Korea. Days to initial rooting decreased as the cutting diameter was reduced. Plant height, leaf number, root length and root weight per plant were favorable as the cutting diameter was small. The ideal cutting diameter was 1-2 mm in this experiment. In the hydroponic cultures, the Japanese standard (JS) nutrient solution was the most effective for multiplication of stem cuttings. It was able to propagate more than 20 times a month from a single mother plant. Viability of plants, which were derived from plug seedlings using stem cuttings, was excellent when transplanted to the field. The number of tubers and tuber yield in both of the plug seedlings and seed potato planting plots were high when planted on 25 August. The number and yield were reduced when planted on 15 August, 5 September and 15 September. The degree of decrease of tuber yield in the plug seedling planting plot however, was lower than that of seed potatoes when the planting date was late. In the case of small tubers (under 30 g), the number of tubers and tuber yield were evidently increased in the seed potato tuber planting plot; the yield of large tuber (over 80g) in the plug seedling planting plot was higher than that of the seed potato. The total tuber yield per plant in the plug seedling planting plot was less than that of the seed potato; therefore, in order to increase tuber yield it was necessary to increase field plant density.

• 아시안잔디학회지
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• 제17권2_3호
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• pp.87-97
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• 2003

The growth characteristics of creeping bentgrass seeded in the seaside landfill golf course are as follows. 1. As a result of analysis on the chemical characteristics of soil mixture used for turfgrass ground in this experiment, soil pH was 7.9, which is somewhat higher than the creeping bentgrass reference value of pH 5.5∼6.5; T-N(%) was 0.02, which is proper for the reference value, and trace element too lacked. 2. The cultivar with the fastest water infiltration was Seaside II recorded as 226.2cm/sec, while that with the slowest water infiltration was Pennlinks recorded as 141.1 cm/hr which was too faster than the USGA water infiltration reference value of 15∼30cm/hr. For the surface hardness of turfgrass ground with different cultivars, no statistically significant variation was found between the Penncross grass and the Pennlinks recorded as 18.6mm and 19.1 mm, respectively. The soil penetration was the highest in Pennlinks recorded as 7.6kg/$\textrm{cm}^2$ and lowest in Penn A-1 as 6.1kg/$\textrm{cm}^2$. 3. As a result of evaluation on visual quality at the early stage of growth, Penncross showed the most excellent visual quality compared to the others. However, Penn A-1 showed the most excellent visual quality at a late stage of growth around Sep. 17, 2003, and it was also excellent in the evaluation of visual color. Seaside II showed higher density around the root and the longest root length and was highly resistant to salt compared to others, but the initial sprouting rate was not satisfied, and the visual quality in the summer season was inferior to others. 4. As a result of measurement of the traffic injury, Penncross showed the most tolerant to the traffic stress and Pennlinks showed the most susceptible.