• 원예과학기술지
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• 제32권4호
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• pp.463-472
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• 2014

Ion imbalance in recycled nutrient solutions is caused by selective ion uptake of plants, which occurs at different rates in different growth stages. The objectives of this study were to investigate the ion balances in both recycled nutrient solutions and rockwool media using different renewal patterns for the nutrient solutions, and to analyze the subsequent effects on uptake of water and nutrients. Over 12 weeks of paprika cultivation, two different renewal patterns (week units) of 6-4-2 and 8-2-2 weeks were compared with a constant renewal pattern of 4-4-4 weeks (control). The nutrient solution in the reservoir tank was constantly maintained at EC $2.5dS{\cdot}m^{-1}$ and pH 5.5-6.5. The changes in the ion balance with the 4-4-4 week pattern were smaller than those with the other treatments. In the early growth stage, however, the ion balances similarly changed among all treatments. Greater changes were subsequently observed for the 6-4-2 week pattern. Although fruit yield and shoot fresh weight of paprika were the lowest with 6-4-2 renewal pattern, no significant differences were observed. Our results indicate that renewal intervals can be extended in consideration of growth stage for more efficient and practical operations in closed soilless cultures.

• 전기화학회지
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• 제2권2호
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• pp.75-80
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• 1999

Li-ion 2차전지는 정극재료로 리튬전이금속산화물을, 부극재료로 탄소를 사용한다. 고용량 및 장수명을 지닌 Li-ion 2차 전지를 제작하기 위하여, 충전중에 탄소표면에 리튬 석출이 없이 전극 활물질의 이용율은 가능한 높아야 한다. 정극 및 부극 재료의 balance 및 적절한 충전 방식이 Li-ion 2차전지의 설계에 있어서 중요한 요소이다. 본 연구에서는 $LiCoO_2/MPCF$전지의 성능에 미치는 정$\cdot$부극 중량비의 효과를 고찰하였다. 먼저 각 반전지의 충방전 특성을 평가하였다. 그리고 흑연화 MPCF를 부극으로, $LiCoO_2$를 정극으로 사용하여 원통형 Li-ion 2차전지를 제작하였다. 기준전극으로 리튬금속을 사용하여 $LiCoO_2/MPCF$전지에서 각 반전지의 전위를 측정하였다. 또한 중량비에 따른 $LiCoO_2/MPCF$ 전지의 충방전 수명 성능을 평가하였다. 시험 결과, $LiCoO_2$ 정극의 이용율은 중량비에 의존하지 않지만, MPCF부극 이용율은 중량비에 크게 의존하였다. 또한, $LiCoO_2/MPCF$전지의 최적 중량비는 $2.0\~2.2$인 것으로 판단되었다.

• 한국표면공학회지
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• 제37권4호
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• pp.220-225
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• 2004

A new ion beam extraction system is designed using a simple ion mass filter and a micro mass balance and a QMS based detecting system. A quadrupole Mass Filter is used for selective ion beam formation from inductively coupled high density plasma sources with appropriate electrostatic lens and final analyzing QMS. Also a quartz crystal microbalance is set between a QMF and a QMS to measure the etching and polymerization rate of the mass selected ion beam. An inductively coupled plasma was used as a ion/radical source which had an electron temperature of 4-8 eV and electron density of $4${\times}$10^{11}$＃/㎤. A computer interfaced system through 12bit AD-DA board can control the pass ion mass of the qmf by setting RF/DC voltage ratio applied to the quadrupoles so that time modulation of pass ion's mass is possible. So the direct measurements of ion - surface chemistry can be possible in a resolution of $1\AA$/sec based on the qcm's sensitivity. A full set of driving software and hardware setting is successfully carried out to get fundamental plasma information of the ICP source and analysed $Ar^{+}$ beam was detected at the $2^{nd}$ QMS.

• 원예과학기술지
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• 제29권1호
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• pp.29-35
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• 2011

EC 기준의 순환식 수경재배시스템에서 재사용 양액 내의 이온 농도의 변화와 각 이온의 EC 기여 비율의 변화는 안정적인 양액 관리를 위해서 고려되어야 할 중요한 요인이다. 본 연구는 초기 생육단계 파프리카의 EC 기준 순환식 수경재배에서 교체 주기에 따른 재사용 양액 내 이온 농도, 이온균형 및 이온의 EC 기여도의 변화를 조사하여 재사용 양액의 적정 분석 주기를 규명하고자 수행하였다. 실험은 파프리카의 평균 마디수가 13마디일 때 시작하였고, 처리 종료시점에서는 평균 마디수가 18마디였다. 1개의 암면 슬라브당 3주의 파프리카가 재배되었다. 처리는 재사용 양액의 교체 주기에 따라 각각 1주, 2주, 3주, 4주 교체 처리구로 구성되었다. 양액은 일사비례제어방식으로 급액되었다. 배액은 배액 탱크에 수집된 후에 당일 관수가 종료된 후 혼합 탱크에서 EC $2.69dS{\cdot}m^{-1}$가 될 때까지 희석되었다. 혼합된 양액은 익일의 양액으로 사용되었다. 재사용 양액은 주기적으로 수집하여 분석되었다. 교체 주기에 따른 이온 농도의 변화는 처리별 차이가 나타나지 않았다. 모든 처리구에서 이온 농도의 변화 범위는 각각 $K^+$ 5-8, $Ca^{2+}$ 11-14, $Mg^{2+}$ 2.0-2.7, $Na^+$ 0.5-0.6, $NO_3{^-}$ 14-19, ${SO_4}^{2-}$ 4-5, ${PO_4}^{3-}$ 1-4, $Cl^-$ $0.3-0.5meq{\cdot}L^{-1}$와 같았다. 교체 주기에 따른 이온 균형 변화는 크지 않았다. 그러나 전체 처리구에서 이온 비율의 변화는 일정한 경향을 나타냈다. 양이온 비율 변화는 $K^+$ : $Ca^{2+}$을 중심으로 나타났으며, 음이온은 ${SO_4}^{2-}$ : ${PO_4}^{3-}$를 중심으로 나타났다. 양액 중의 $K^+$, $NO_3{^-}$, $H_2PO_4{^-}$의 1가 이온과 $Ca^{2+}$, $Mg^{2+}$, ${SO_4}^{2-}$의 2가 이온의 활동도 계수는 각각 0.8-0.9, 0.5-0.6 사이에서 변하였고, 시간 경과와 함께 각 이온의 활동도 계수는 일정한 경향을 나타냈다. 각 이온이 양액의 EC에 기여한 비율은 $K^+$와 $NO_3{^-}$가 가장 컸고, 다음으로 $Ca^{2+}$, ${SO_4}^{2-}$, $Mg^{2+}$ 순으로 나타났다. 본 실험에 적용한 교체 주기 4주는 초기 생육단계의 파프리카를 EC 기준 순환식으로 수경재배 할 경우, 이온 농도 변화와 이에 따른 EC 기여도의 변화는 안정적인 범위 이내라고 판단된다.

• Mycobiology
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• 제38권4호
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• pp.302-309
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• 2010

Formic acid is a representative carboxylic acid that inhibits bacterial cell growth, and thus it is generally considered to constitute an obstacle to the reuse of renewable biomass. In this study, Saccharomyces cerevisiae was used to elucidate changes in protein levels in response to formic acid. Fifty-seven differentially expressed proteins in response to formic acid toxicity in S. cerevisiae were identified by 1D-PAGE and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analyses. Among the 28 proteins increased in expression, four were involved in the MAP kinase signal transduction pathway and one in the oxidative stress-induced pathway. A dramatic increase was observed in the number of ion transporters related to maintenance of acid-base balance. Regarding the 29 proteins decreased in expression, they were found to participate in transcription during cell division. Heat shock protein 70, glutathione reductase, and cytochrome c oxidase were measured by LC-MS/MS analysis. Taken together, the inhibitory action of formic acid on S. cerevisiae cells might disrupt the acidbase balance across the cell membrane and generate oxidative stress, leading to repressed cell division and death. S. cerevisiae also induced expression of ion transporters, which may be required to maintain the acid-base balance when yeast cells are exposed to high concentrations of formic acid in growth medium.

• 한국항공우주학회지
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• 제34권4호
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• pp.89-101
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• 2006

본 논문에서는 HAUSAT-2 전력계의 설계와 각 모드별로 에너지 평형 해석을 통한 전력계 설계의 타당성을 검증하였다. 태양전지판은 GaAs 셀을 사용하였고 디지털 방식의 최대 전력 추적기를 채택하였다. 배터리 팩은 4개의 Li-Ion 셀로 구성하였고 최대 전력 추적기와 배터리 충전 조절기로 배터리 충전 기능을 구현하였다. 전력 제어기는 DC-DC 변환기로 요구되는 전압을 출력하고 상용 IC 및 MOSFET으로 이루어진 전력 분배기가 서브시스템 및 탑재체에 전력을 분배시킨다. 전력생성 분석은 다양한 승교점 지방시(LTAN)를 가지는 궤도를 고려하여 수행하였으며, 이 중 HAUSAT-2의 임무 수행에 적합한 궤도를 선정하여 모드별 전력 사항을 반영하여 에너지 평형 해석(EBA)을 진행하였다.

• 한국대기환경학회지
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• 제10권2호
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• pp.98-104
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• 1994

Precipitation samples were collected at Kosan, Cheju Island over a period of 6 months An automatic rain sampler was manufactured domestically and installed at Kosan station. All samples were collected on a weekly basis. Samples were analyzed for S $O_4$$^{=}$, N $O_3$$^{[-10]}$ , C $l^{[-10]}$ , N $H_4$$^{+}$, N $a^{+}$, $K^{+}$, $Ca^{++}$, $Mg^{++}$, and pH and specific conductivity. The quality analysis of rain sample data were performed based on ion balance and specific conductivity. The pH of rain samples ranged between 4.6 to 6.6. Bicarbonate ion concentration were included in ion balance and specific conductivity calculations. The sum of cation concentrations were slightly greater than the sum of anion concentrations. Calculated specific conductivity was greater than measured specific conductivity. The most probable explanations for this discrepancy is "an anion too low or anion missing." Two criteria were used to identify outliners. They are 1) the difference between the sum of anion concentrations and cation concentration is more than 50 $\mu$eq./1 and 2) the difference between calculated and measured specific conductivity is more than 25%. Chemical analysis from several samples did not satisfy these quality control criteria. Volume weighted average concentrations were calculated. Dominant free acids in rain samples were N $a^{+}$, C $l^{[-10]}$ , S $O_4$$^{=}$, N $O_3$$^{[-10]}$ ions in order of abundance. Non-seasalt sulfate comprises 76% of total sulfate.sulfate.e.ate.e.

• 방사성폐기물학회지
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• 제16권1호
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• pp.65-82
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• 2018

With the significant increase in spent ion-exchange resin generation, to meet the requirements of Waste Acceptance Criteria (WAC) of the Wolsong disposal facility in Korea, blending is considered as a method for enhancing disposal options for intermediate level waste from nuclear reactors. A mass balance formula approach was used to enable blending process with an appropriate mixing ratio. As a result, it is estimated around 44.3% of high activity spent resins can be blended with the overall volume of low activity spent resins at a 1:7.18 conservative blending ratio. In contrast, the reduction of high activity spent resins is considered a positive solution in reducing the amount of spent resins stored. In an economic study, the blending process has been proven to lower the disposal cost by 10% compared to current APR1400 treatment. Prior to commencing use of this blending method in Korea, coordinated discussion, and safety and health assessment should be undertaken to investigate the feasibility of fitting this blending method to national policy as a means of waste predisposal processing and management in the future.

• Bulletin of the Korean Chemical Society
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• 제7권6호
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• pp.428-433
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• 1986

It is demonstrated by using a highly positive uranium ion as a test case that the exact relation between the small and the large components of a Dirac spinor in relativistic self-consistent-field (RSCF) calculations is not fully satisfied by the kinetic balance condition only even for two electron systems. For a fixed number of large component basis functions, total energies are sensitive to the change of the size of the small component basis sets even after the kinetic balance condition is fully satisfied. However, the kinetic balance condition appears to be a reasonable guideline in generating reliable and practical basis sets for most applications of RSCF calculations. With a complete small component basis set, energies from RSCF calculations exhibit a variational behavior, implying the stability of the present RSCF procedure.

• Journal of Power Electronics
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• 제18권4호
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• pp.1127-1139
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• 2018

A reduced particle-unscented Kalman filter estimation method, along with a splice-equivalent circuit model, is proposed for the state-of-charge estimation of an aeronautical lithium-ion battery pack. The linearization treatment is not required in this method and only a few sigma data points are used, which reduce the computational requirement of state-of-charge estimation. This method also improves the estimation covariance properties by introducing the equilibrium parameter state of balance for the aeronautical lithium-ion battery pack. In addition, the estimation performance is validated by the experimental results. The proposed state-of-charge estimation method exhibits a root-mean-square error value of 1.42% and a mean error value of 4.96%. This method is insensitive to the parameter variation of the splice-equivalent circuit model, and thus, it plays an important role in the popularization and application of the aeronautical lithium-ion battery pack.