• Journal of radiological science and technology
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• v.30 no.2
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• pp.161-165
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• 2007

Ultrasonic absorption spectrum in bovine serum albumin aqueous solutions have been measured at $20^{\circ}C$ over the broad frequency range $0.2{\sim}1,000\;MHz$ at pH 7. The absorption spectrum observed at neutral pH was successfully analyzed with the distribution of relaxation time assuming a mirror-image curve of the Davidson-Cole function. This distribution function suggests that hydration of BSA molecules is responsible for the absorption.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.63-67
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• 1989

In order to examine the suppressive effect of dietary fiber toward the intestinal absorption of lead, an in vitro absorption test using a semipermeable membrane was undertaken. Among dietary fiber components, cellulose showed no suppressive effect, guar gum and carboxymethyl-cellulose, a slight effect whereas citrus pectin and sodium alginate exhibited a remarkable effect. Among fibrous foods tested, rice bran, wheat bran, Chinese cabbage, radish and tangle had a higher suppressive effect while mandarin orange, apple and laver showed a lower effect.

• Journal of agriculture & life science
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• v.53 no.1
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• pp.13-21
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• 2019

This study was carried out to acquire basic data for a long-term hydroponic culture through investigating water and inorganic ion uptake characteristics at different EC level of nutrient solution of three tomato varieties. Three different tomato varieties, the European type(cv. Daphnis), the Asian type(cv. Super Doterang) and cherry type(cv. Minichal), were used for the investigation. Also, the deep flow technique(DFT) was applied. The three different electrical conductivity(EC) level(1.0, 2.0, 3.0, and 4.0 dS·m-1) of hydroponic nutrient solution were used as variable. At a high EC level of nutrient solution, the leaf area and fresh weight decreased in the early stage, and its growth(plant height, leaf number, leaf area, fresh-weight) was poor with salt stress. Result showed that the higher the EC level of the nutrient solution, the lesser was water uptake. The water uptake was not significantly different from varieties in the first survey, but In the second survey, the 'Daphnis' did not show a significant decrease in water uptake in the EC level higher than 2.0 dS·m-1., on the other hand, 'Super Doterang' presented very low water uptake. At a low EC level, N, P, and K, were absorbed more than the concentration of the irrigation water, while Ca, Mg, S uptake were low. At a high EC level, almost ions absorbed less than 50% of the initial concentration of irrigation water. Thus, imbalance among ions was severe at low EC level compared to high EC level. 'Daphnis' was a variety that effectively utilize nutrients under nutrient stress, showing high absorption at low concentration condition and low absorption at high concentration condition. However, 'Daphnis' suffered most seriously by absorbing nutrients excessively.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.166-172
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• 2022

A method of efficiently purifying high value-added indole among components of coal tar absorption oil was studied using a step-by-step process of extraction-distillation-crystallization. The coal tar absorption oil used in this study contains 1.2% naphthalene, 0.1% quinoline, 0.4% isoquinoline, 6.4% indole, 21.0% 1-methylnaphthalene, 48.8% 2-methylnaphthalene, and 11.7% biphenyl as main components. For the separation and purification of indole, methanol was first used as a solvent to separate indole species in the coal tar absorption oil into an extract phase. And then methanol was recovered by distillation. Subsequently, an extraction solution where methanol was removed was mixed with normal hexane, and then crystallized to recover indole having a purity of 99.3%. Based on the experiments of this study, a purification process scheme for indole in coal tar absorption oil was proposed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.458-465
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• 1993

Water culture experiments were carried out to elucidate the effects of N availability, temperature and water potential of culture solution on the uptake and assimilation of N and dry matter accumulation by barley seedlings. N assimilation and dry matter accumulation at 3 to 4 leaves stage in barley plants were maximized at about 3.4 % of N concentration in leaf. N assimilation by barley plants increased with increase of nitrate concentration up to 80ppm in the solution. Over this level nitrate began to accumulated in the leaves and stems proportionally to the N availability in culture solution. Nitrate reductase activity increased in parallel with the increase in the concentration of reduced N in leaves. N uptake by barley plants decreased markedly when water potential reduced below -2 bar or when temperature dropped below 5$^{\circ}C$. These results suggest that the basal application rate of N, 60kg per hectare, for the barley crop needs to be re-examined under the concept of N use efficiency with taking into consideration of temperature and soil N availability because about a half of N accumulated in the leaves of barley plant before wintering is known to be lost by winter killing of above-ground part of the plant.

• Composites Research
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• v.19 no.1
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• pp.36-42
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• 2006

MWNT(multi-walled carbon nanotube)-filled plain-weave glass/epoxy composites were fabricated and electromagnetic characteristics of the composites were investigated. The observation of the microstructures of the composites revealed that MWNTs are mostly distributed in matrix rich region and the interface between glass fiber yarns in warp and fill direction. The permittivity of the composites, measured in X-band (8.2-12.4 GHz) frequency range, increased with weight fraction of MWNTs and remained almost constant with frequency. The measured permittivity was used to investigate the reflection loss of radar absorbing structures (RAS) composed of MWNT-filled composites according to thickness and a RAS were constructed with 10 dB absorbing bandwidth 4.2 GHz and 3.3 mm in thickness.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.947-953
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• 2017

In this study, the regeneration efficiency of the amino acid salt absorbent which can be applied to carbon dioxide absorption / regeneration process was confirmed. The regeneration efficiency has a great influence on the economical judgment of the process. so, continuous regeneration experiment was conducted to establish economical process. The amino acid salts used in the experiments are Potassium L-lysinate and Potassium L-alaninate. Each amino acid and potassium hydroxide(KOH) were mixed at a 1: 2 molar ratio. In order to confirm the regeneration efficiency of the absorbent, carbon dioxide was absorbed in the two materials, and the carbon dioxide desorption experiment was carried out by heating. The initial reaction rate was L-alanine was faster. Over time, L-lysine, desorption higher concentrations of carbon dioxide. L-lysine showed higher regeneration efficiency than L-alanine, (L-alanine 47.26% and L-lysine 62.11%). As a result of the continuous regeneration experiment using the L-lysine having good absorption and regeneration efficiency, it was confirmed that the regeneration efficiency decreases as the number of regeneration increases.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.2
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• pp.121-131
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• 2021

Magnesium (Mg) present in carbonate minerals as impurities has been used as a geochemical proxy to infer the environmental conditions where the minerals precipitated. The reliability of Mg geochemical proxies requires fundamental understanding of Mg incorporation into minerals based on accurate speciation of Mg ²⁺ in the crystal structure, which is determined mainly by application of X-ray absorption spectroscopy (XAS). However, high uncertainties are involved in interpreting the XAS spectra of minerals containing trace amount of Mg ²⁺. Because density function theory (DFT) can predict an XAS spectrum for a crystal structure, DFT calculations can reduce the uncertainties in the interpretation of the XAS spectrum. In this study, we calculated ab initio Mg K-edge absorption spectra of Mg silicates and (hydr)oxides based on DFT and analyzed the correlation between the calculated spectra and Mg structural parameters. Our ab initio Mg K-edge absorption spectra well reproduced the key features of the experimental spectra. The absorption-edge positions of the calculated spectra showed the weak positive correlation with the average Mg-O bond distance or Mg effective coordination number. The current study shows that DFT-based core-level spectroscopy method is a powerful tool in providing standard Mg K-edge spectra of diverse Mg minerals and determining the Mg chemical species within carbonate minerals.

• The Science & Technology
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• v.33 no.3 s.370
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• pp.12-14
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• 2000

과학기술은 새로운 밀레니엄시대를 주도할 핵심분야로 국가경쟁력의 근원이 될 것이다. 과학기술이 낙후되면서 세계시장에서 설자리를 잃게되고 민족의 자부심도 지킬 수 없게 된다. 기존제품을 복사함으로써 개발비를 줄여 이익을 보는 시대는 이미 지나갔다. 새로운 시대를 맞아 과학발전을 위해서는 박사학위를 소지한 고급인력을 기업에서 흡수하여 장치와 부품, 재료에 대한 연구를 기초에서부터 다져 고부가가치를 창출해야 한다. 또 교육도 창의적으로 스스로 생각하는 훈련이 이루어져 독특한 재능을 지닌 과학기술의 탁월한 영재들을 많이 발굴해야 할 것이다.

• Bulletin of Food Technology
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• v.14 no.4
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• pp.87-94
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• 2001

Inflammatory bowel disease (IBD)환자의 유가공품 내성에 대한 병력과 의사나 영양학자로부터 받은 지침은 IBD환자들의 관리에 있어서 중요한 주안점이 된다. 대부분의 환자들이 불편 없이 매일 우유를 마실 수 있지만 부가적인 고찰에서는 개인적 요소와 크게 관련이 있는 특정요소가 있다는 것이다. 유가공품에 민감한 IBD 환자들의 진단으로 lactose의 내성과 흡수 장애, long- chain 지방산, 우유에 대한 알러지, 유가공품에 대한 심리적인 요소와 부정적인 인식 등이 있다. 유당 흡수장애의 발생빈도는 결장이나 ulcerative colitis (UC)를 포함하는 Crohndisease (CD)환자에서보다 소장의CD환자에서 더 높다. 유당 흡수장애의 후천적인 발생빈도는 유전적 요소에 기인하는 인종적 요인에 의해 주로 결정된다. 게다가 소장의 CD에서 유당 흡수장애는 lactase 효소보다도 세균성 이상증식이나 소장에서 통과하는 시간(small bowel transit time) 과 같은 요소에 의해 결정된다. 의사들이 IBD환자에게 내리는 지침에 있어서의 의견은 매우 다양하며, 진단이 내려지면 유가공품을 회피하라는 극단적인 충고가 있는 반면에IBD의 조절에 있어서 유가공품의 섭취를 줄이라는 제안을 내리는 경우도 있다. IBD환자들은 대중적인 식이요법 책의 저자들이나 의사들로부터 임의적인 제안과 환자들의 부정적 인식 때문에 우유 불내증이나 유당 흡수장애의 발병율의 근거가 거의 없는데도 필요이상으로 유가공품을 피한다. 따라서, 충분한 과학적.임상적 정보의 축적은 IBD환자들에게 유가공품의 섭취에 대한 지침을 설정하는 데에 유용하다.