• 한국작물학회지
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• 제50권1호
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• pp.16-21
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• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.

• Journal of electromagnetic engineering and science
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• 제13권3호
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• pp.173-177
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• 2013

This paper presents a new method for analyzing the maximum efficiency of a wireless power transfer (WPT) system with multiple n resonators. The method is based on ABCD matrices and allows transformation of the WPT system with multiple n resonators into a single two-port network system. The general maximum efficiency equation of a WPT system with multiple n resonators is derived using the ABCD matrix. Use of this equation allows placement of the relay resonators for maximum efficiency even though they are asymmetrical. The general maximum efficiency equation and the method of the optimum placement are verified by a full wave simulation. The results show that the method is useful for the analysis of a WPT system with relay resonators.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2021년도 추계학술대회
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• pp.128-128
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• 2021

• 현장농수산연구지
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• 제20권1호
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• pp.175-185
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• 2018

개체군생장율(CGR)은 유수형성기와 출수기 사이에 가장 높았는데, 주남벼, 낙동벼, 소비벼 등이 높았으며, 이삭의 등숙속도는 시비량이 증가할수록 증가하였고, 출수 후 20일까지 가장 많이 증가하고, 그 이후에는 점차 감소하는 경향이었는데, 주남벼, 소비벼에서 빨랐다. 관행재배에서 수량이 높은 품종은 소비재배에서도 수량이 높았으며, 소비재배시 수량에 가장 많은 영향을 미치는 수량구성요소는 단위면적당 영화수로, 고도의 정의 상관관계를 나타냈다. 또한 백미품위는 시비량이 증가할수록 감소하였는데, 소비벼의 품위가 가장 낮았으며, 사미와 분상 질립의 증가가 원인이었다.

• Applied Biological Chemistry
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• 제25권3호
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• pp.150-154
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• 1982

중질소요소(重窒素尿素)를 사용(使用) 3품종(品種)에 대(對)한 분시시험(分施試驗)을 폿드에서 수행하였다. 2회분시(回分施)는 4회분시(回分施)보다 통일계(統一系)에 월등히 좋았다. 시비효율(Fe), 이용율(利用率) 및 흡수시비질소효율(吸收施肥窒素效率)(Ef)은 4회분시(回分施)보다 2회분시(回分施)에서 월등히 컸다. Fe의 순위는 Ef의 순위와 같았다. 수량(收量)과 중질소과잉율(重素窒過利率)은 통일계(統一系)가 생육초기(生育初期)에 시용질소(施用窒素)를 많이 흡수(吸收)하여 후기(後期)에 상당히 재전류(再轉流)시킴을 나타내었다. 흡수시비질소(吸收施肥窒素)에 대(對)한 토양질소흡수증가량(土壤窒素吸收增加量) $({\Delta}Ns/Nf)$은 시비(施肥)로 인(因)한 토양질소이용율(土壤窒素利用率)의 지표(指標)가 될 수 있다.

• 마이크로전자및패키징학회지
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• 제28권1호
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• pp.13-20
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• 2021

GaN은 III-V족 화합물 반도체로 밴드갭을 조절하는 것이 가능하고 화학적으로 안정하기 때문에 다른 물질에 비해 산성, 염기성 용액에서 부식이 적다. 또한 GaN의 밴드갭이 물의 산화·환원 준위를 포함하고 있어 외부전압 없이 물 분해가 가능하다는 장점이 있다. 하지만 GaN 자체만으로는 태양광-수소 변환 효율(solar-to-hydrogen conversion efficiency, STH)이 낮아 이를 개선하기 위해 최근 활발한 연구가 이루어지고 있다. 본 총설에서는 GaN을 PEC 물분해의 광전극으로 사용하기 위한 방법들과 연구에 대해 정리하였다.

• 한국초지조사료학회지
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• 제41권4호
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• pp.280-286
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• 2021

The objective of this study was to prove the effect of pig slurry application with charcoal on nitrogen use efficiency (NUE), feed value and ammonia (NH₃) emission from maize forage. The four treatments were applied: 1) non-pig slurry (only water as a control), 2) only pig slurry application (PS), 3) pig slurry application with large particle charcoal (LC), 4) pig slurry application with small particle charcoal (SC). The pig slurry was applied at a rate of 150 kg N ha^-1, and the charcoal was applied at a rate of 300 kg ha-1 regardless of the size. To determine the feed value of maize, crude protein, dry matter intake, digestible dry matter, total digestible nutrient, and relative feed value were investigated. All feed value was increased by charcoal treatment compared to water and PS treatment. Also, the NUE for plant N was significantly higher in charcoal treatments (LC and SC) compared to PS treatment. On the other hand, there is no significant difference for feed value and NUE between LC and SC. The NH₃ emission was significantly reduced 15.2% and 27.9% by LC and SC, respectively, compared to PS. Especially, SC significantly decreased NH₃ emission by 15% compared to LC. The present study clearly showed that charcoal application exhibited positive potential in nitrogen use efficiency, feed value and reducing N losses through NH₃ emission.

• 한국토양비료학회지
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• 제48권5호
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• pp.372-378
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• 2015

Growing crops under different soil textures may affect crop growth and yield because of soil N availability, soil N leaching, and plant N uptake. The objective of this study was to evaluate effects of three different soils (sandy loam, loam, and clay loam) on cucumber (Cucumis sativus L.) yield, nitrogen (N) use efficiency (NUE), and water use efficiency (WUE) by subsurface drip fertigation in the greenhouse. Three different soil textures are sandy loam, loam, and clay loam with 3 replications. The dimension of each lysimeter was $1.0m(W){\times}1.5m(L){\times}1.0m(H)$. Cucumber was transplanted on April $8^{th}$ and Aug $16^{th}$ in 2011. The subsurface drip line and tensiometer was installed at 30 and 20 cm soil depth, respectively. An irrigation with $100mg\;NL^{-1}$ concentration was automatically applied when the tensiometer reading was 10 kPa. Volumetric soil water content for cucumber cultivation was the highest in 30 cm soil depth regardless of soil texture and was lowered when soil depth was deeper. The volumetric soil water contents at soil depths of 10, 30, 50, and 70 cm were the highest at clay loam, followed by loam, and sandy loam. The growth of cucumber at the $50^{th}$ day after transplanting was the lowest at sandy loam. Cucumber fruit yields were similar for all three soil textures. The highest amount of water use at sandy loam was observed. Nitrogen and water use efficiencies for cucumber were higher for clay loam, followed by loam and sandy loam, while the amount of N leaching was the greatest under sandy loam, followed by loam, and clay loam. Overall, growing cucumber on either loam or clay loam is better than sandy loam if subsurface drip fertigation is used in the greenhouse.

• 한국작물학회지
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• 제50권1호
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• pp.22-27
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• 2005

To find out the optimum mixture ratio of ammonium and nitrate on rice plant, 4 rice varieties were examined during 14days after transplanting in hydroponics with the different ratio of ammonium to nitrate(100 : 0, 75: 25,50: 50, 25: 75 and 0: 100). The highest N uptake from solution and the maximum plant dry weight were $60\~70\%$ ammonium and $30\~40\%$ nitrate mixture treatment both in Japonica and Tongil type rice plants. And with the same varieties N-uptake and N use-efficiency were compared between 10.0 mM and 1.0 mM nitrogen using $70\%$ ammonium and $30\%$ nitrate for 24 days after transplanting. Rice plants absorbed more nitrogen$(131\~145\%)$ in 10.0mM than 1.0mM treatment but accumulated N in rice plants were almost the same in both treatment. Among the tested rice cultivars, dry matter production and total accumulative nitrogen in rice plants were much high in Tongil type than japonica type rice cultivars. N-recovery ratios of rice plants from uptake N were $90.8-99.0\%$ in low concentration N solution(1.0 mM), but $69.4-81.7\%$ were observed in high concentration N solution(10.0 mM). It means that suppling low concentration N steadily will be better to prevent loss of N without reducing of growth in rice plants.

• 한국환경농학회지
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• 제18권4호
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• pp.304-309
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• 1999

소나무, 일본잎갈나무, 자작나무 묘목을 대상으로 온실 내에서 질소와 인 비료를 사용하고, 묘목 생체량, 잎, 줄기, 뿌리 등의 부위별 양분 농도, 그리고 양분이용효율에 미치는 영향을 연구하였다. 대부분의 경우 시비가 묘목의 생체량 변화에 미치는 효과는 없는 것으로 나타났다. 그러나 시비 후 묘목 내 부위별 질소와 인 농도는 증가하였다. 이러한 결과는 시비가 묘목을 양분 과다 이용상태에 이르게 한 것으로 사료되었다. 양분이용효율은 지상부와 지하부 생체량에 대한 묘목 내 양분 함량의 비로 계산하였는데, 시비 후 질소와 인의 이용효율은 소나무와 자작나무에서 감소하였으나, 일본 잎갈나무에서는 변화를 보이지 않았다. 수종별 양분이용효율은 자작나무에서 가장 높고, 소나무와 일본잎갈나무의 순으로 점차 감소하는 것으로 나타났다.