• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.712-714
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• 1999

The rate constants for the nucleophilic addition of potassium cyanide to α,N-diphenylnitrone and its derivatives (p-OCH3, p-CH3, p-Cl, and p-NO2) were determined by ultraviolet spectrophotometer at 25℃, and the rate equations which can be applied over a wide pH range were obtained. On the basis of pH-rate profile, adduct analysis, general base catalysis and substituent effect, a plausible mechanism of this addition reaction was proposed: At high pH, the cyanide ion to carbon-nitrogen double bond was rate controlling, however, in acidic media, the reaction proceeded by the addition of hydrogen cyanide molecule to carbon-nitrogen double bond after protonation at oxygen of a,N-diphenylnitrone. In the range of neutral pH, these two reactions occured competitively.

• 자연과학논문집
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• 제12권1호
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• pp.81-84
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• 2002

식물 중 단자엽을 제외한 쌍자엽 식물은 선택적으로 제거할 수 있는 헤테로 고리 화합물을 기존에 알려진 방법보다 용이하게 합성할 수 있는 방법을 연구하였으며, 과정에 일부 헤테로 고리 치환기의 4위치에 염소기가 치환된 화합물 5a를 70%수율로 하는 5b는 74%수율로 각각 수득하였다. 술폰 산화제로 potassium percarbonate를 사용하였을 때 1)의 화합물을 90%수율로 고순도 화합물을 수득하였으며 2)의 경우 85%의 고수율, 고순도 화합물을 수득하였다. Sodium hypochlorite의 경우 피리미딘 헤테로 고리에 염소가 치환되는 불순물 생성으로 적합지 않음이 판명되었다.

• Journal of Plant Biology
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• 제20권3호
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• pp.109-118
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• 1977

Seasonal distribution of N, P and K contents and their cycling were studied in Korean oak (Quercus acutissima) and Korean alder (Alnus sibirica) stands in central part of Korean peninsula. The amounts of three minerals were high in young leaves but gradually decreased with the process of leaf development in both stands. The amounts of minerals in the branches, trunks and roots were decreased in summer, however, they increased again in autumn. Seansonal changes of these minerals were not significant in the two stands. The amounts of phosphorus and potassium in plant and soil were higher in the oak stand than the alder one, but those of nitrogen were reversed. The amounts of minerals absorbed during one year were greater in the oak stand than in the alder one, but those returned into soil through mineralization of litter were less in the former than in the latter. The nutrient requirements of the oak stand were greater than the alders, but the cycling rate, the ratio of the amount of minerals absorbed to returned, was opposite.

• 한국결정성장학회지
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• 제8권3호
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• pp.396-400
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• 1998

KLN은 성장 결정 내의 $Nb_2O_5$함유량에 따라 물성이 크게 변화하므로 단결정의 조성제어가 매우 중요하다. 본 실험에서는 초기 KLN용액의 $Nb_2O_5$함량을 증가시켜 $Nb_2O_5$함유량이 높은 KLN단결정을 온도요동법과 TSSG법에 의해 성장시키고 성장된 KLN단결정인 $Nb_2O_5$증가량에 따른 격자결함의 유무를 관찰하고자 유전 및 광학 특성을 관찰하다. KLN 단결정 내에 격자결함의 증가에 의해 낮은 에너지로의 단락 frequency 이동과 DPT 특성을 보이는 넓은 Curie 범위가 관찰되었다.

• 대한의생명과학회지
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• 제15권2호
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• pp.127-133
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• 2009

This study was designed to investigate the effects of high concentration of (-)-epigallocatechin-3-gallate(EGCG) on the neuronal activity of rat substantia nigra dopaminergic neurons. Sprague-Dawley rats aged 14 to 16 days were decapitated under ether anesthesia. After treatment with pronase and thermolysin, the dissociated dopaminergic neurons were transferred into a chamber on an inverted microscope. Spontaneous action potentials and potassium currents were recorded by standard patch-clamp techniques under current and voltage-clamp modes respectively. 18 dopaminergic neurons(80%) revealed inhibitory responses to 40 and 100 ${\mu}M$ of EGCG and 4 neurons(20%) did not respond to EGCG. The spike frequency and resting membrane potential of these cells were decreased by EGCG. The amplitude of afterhyperpolarization was increased by EGCG. Whole potassium currents of dopaminergic neurons were increased by EGCG(n=10). These experimental results suggest that high concentration EGCG decreases the neuronal activity of the dopaminergic neurons by altering the resting membrane potential and afterhyperpolarization.

• 자원리싸이클링
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• 제22권1호
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• pp.48-54
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• 2013

LCD용 편광필름에 핵심적으로 사용되어진 요오드화칼륨 (KI, Potassium Iodide) 폐용액으로부터 분별결정법을 이용하여 고순도의 요오드화칼륨 결정을 제조하는 실험을 행하였다. 본 연구에서는 붕소, 나트륨 및 PVA 등의 불순물을 포함한 1.3% 요오드화칼륨 폐액을 3회에 걸쳐 농축하였으며, 용해도 차이를 이용하여 최대 불순물인 붕소화합물을 제거하고, 여과지를 이용하여 유기물을 제거하였다. 또한 24시간 숙성을 통하여 $K_2SO_4$ 형태로 불순물을 제거하여 99.5% 이상의 고순도 요오드화칼륨 결정을 제조하였으며, 재결정을 통하여 농축되어진 불순물을 약 70% 제거할 수 있었다.

• Journal of Applied Biological Chemistry
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• 제49권4호
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• pp.154-156
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• 2006

Trace metals in honey have an influence on the taste of honey along with pollens. Western bee honeys, which are mostly collected from acacia, have less than 0.1% of ash. Savor of Korean native-bee honey is thought to be due to the difference of the contents of trace metals. Korean native-bee honeys collected from Jirisan District, which is the greatest producing area of native-bee honey in Korea, showed high contents of ash. Korean native-bee honeys from the districts other than Jirisan District also showed similar results($0.44{\sim}0.83%$ of ash) to those from Jirisan District. Potassium was found to be the principal factor of high content of ash with over 85% of trace metals in ash.

• 한국임상수의학회지
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• 제16권2호
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• pp.272-275
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• 1999

Generally, it is known that the composition of the cation of the dog's RBCs is high in potassium(K) and low in sodium(Na). However, it is reported that certain kinds of dogs have HK, HG phenotype which contains a large amount of reduced glutathione(GSH) by the effect of Na-K pump on the cell membrane of RBC with high concentration of K and low concentration of Na. Although this HK phenotype is not regarded as a disease, it is supposed to be an important assignment to examine the distribution and the occurrence rate of the dogs that contain HK cell in their RBCs for the proper clinical treatments as these HK dogs are very sensitive to aromatic disul-fide or onions and have a tendency to cause hemolysis. Accordingly, present study was performed to measure the concentration of K, Na and GSH in the RBCs of Jindo dogs and that of Dosa dogs at the same time.

• The Plant Pathology Journal
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• 제35권6호
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• pp.684-691
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• 2019

Evolution of adaptive mechanisms to abiotic stress is essential for plant growth and development. Plants adapt to stress conditions by activating the abscisic acid (ABA) signaling pathway. It has been suggested that the ABA receptor, clade A protein phosphatase, SnRK2 type kinase, and SLAC1 anion channel are important components of the ABA signaling pathway. In this study, we report that the shaker type potassium (K⁺) channel, GORK, modulates plant responses to ABA and abiotic stresses. Our results indicate that the full length of PP2CA is needed to interact with the GORK C-terminal region. We identified a loss of function allele in gork that displayed ABA-hyposensitive phenotype. gork and pp2ca mutants showed opposite responses to ABA in seed germination and seedling growth. Additionally, gork mutant was tolerant to the NaCl and mannitol treatments, whereas pp2ca mutant was sensitive to the NaCl and mannitol treatments. Thus, our results indicate that GORK enhances the sensitivity to ABA and negatively regulates the mechanisms involved in high salinity and osmotic stresses via PP2CA-mediated signals.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1727-1732
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• 2017

Pyroprocessing is an alternative method of reprocessing spent fuel, usually involving the dissolving spent fuel in a molten salt media. The National Nuclear Laboratory designed, built, and commissioned a molten salt dynamics rig to investigate the transfer characteristics of molten lithium chloride-potassium chloride eutectic salt. The efficacy and flow characteristics of a high-temperature centrifugal pump and argon gas lift were obtained for pumping the molten salt at temperatures up to $500^{\circ}C$. The rig design proved suitable on an industrial scale and transfer methods appropriate for use in future molten salt systems. Corrosion within the rig was managed, and melting techniques were optimized to reduce stresses on the rig. The results obtained improve the understanding of molten salt transport dynamics, materials, and engineering design issues and support the industrialization of molten salts pyroprocessing.