• 한국수소및신에너지학회논문집
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• 제22권5호
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• pp.616-624
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• 2011

Hydrogen storage and release of Fe/Zr/Mo mixed oxide mediums were investigated by hydrogen reduction and water splitting oxidation($Fe_3O_4+4H_2{\rightleftharpoons}3Fe+4H_2O$). As the results of TPR/O, Mo was an additive to enhance the reactivity of water splitting oxidation as well as the stability of the medium. On the other hand, it seemed that $ZrO_2$ additive provided the passway for the diffusion of gaseous chemicals on the medium in repeated redox cycles. Among the Fe/Zr/Mo mediums, a FeZrMo-7 medium (Fe/Zr/Mo=80/13/7mol%) exhibited the best performance with good durability during five repeated redox cycles. The amount of hydrogen evolved on the medium was maintained at ca. 10.7mmol-$H_2$/g-medium corresponding to the hydrogen storage amount of ca. 2.2wt%.

• 한국안전학회지
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• 제38권3호
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• pp.43-50
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• 2023

Silicone tetrachloride (SiCl₄) leak accidents cause enormous human and environmental damage because it is highly toxic. Some handling facilities use water curtains to reduce the impact range of SiCl₄. Although the water curtain is known as one of the most efficient technologies for post-release mitigation, its effect on reducing SiCl₄ concentration needs to be investigated scientifically and quantitatively. In this study, three-dimensional computational fluid dynamics (CFD) was used to investigate the physical and chemical effects of water curtains as a release-mitigation system for SiCl₄. SiCl₄ is released and dispersed five seconds prior to the operation of the water curtain. Once the water curtain works, the SiCl₄ reacts chemically with the water and its concentration decreases rapidly; it reaches an emergency response planning guidelines level 2 (ERPG-2) of 5 parts per million (ppm) at about 570 m. We observed, however, that the physical effect of water curtains on reducing SiCl₄ concentration is insignificant when the chemical effect is eliminated. These results are crucial since they can be a scientific and quantitative basis for the 'technical guidelines for estimating the accident affected range'. In order to protect the public from chemical accidents, more toxic gas mitigation technologies need to be developed.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.159-159
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• 2003

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2007년도 추계학술논문발표회 논문집
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• pp.193-198
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• 2007

• 폴리머
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• 제31권3호
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• pp.189-193
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• 2007

항암제인 독소루비신의 지속적인 방출을 위하여 PLGA와 독소루비신의 미립구를 수중유형(O/W) 용매증발 방법을 이용하여 약물의 농도와 고분자의 분자량의 변화에 따른 방출거동의 차이를 확인하였다. 이중층 미립구내의 독소루비신의 방출을 분석하기 위하여 형광 분광 광도계를 이용하여 5주 동안 독소루비신의 방출을 보았으며 주사전자현미경을 이용하여 이중층미립구의 단면과 표면을 확인하였다. 제조된 이중층 미립구는 외부층이 전체적으로 매끄러운 표면과 구형을 나타내고 있었고 이중층 미립구의 단면을 잘라 계면층을 중심으로 하여 내부형태와 외부형태를 구분 지을 수 있었다. 또한 제조된 이중층 PLGA 독소루비신 미립구는 방출 결과를 통하여 저분자량의 고분자를 이용할수록 방출이 빠르다는 것을 확인할수 있었다. 따라서 미립구를 제조하는데 있어서 고분자의 분자량을 조절함으로써 방출거동을 조절할 수 있다는 것을 확인하였다.

• Journal of Pharmaceutical Investigation
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• 제37권2호
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• pp.101-106
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• 2007

Venlafaxine, 1-[2-(dimethylamino)-1-(4-methoxyphenyl)ethyl] cyclohexanol hydrochloride is a novel, nontricyclic antidepressant. venlafaxine is a unique antidepressant that differs structurally from other currently available. The aim ot the study was to formulate sustained-release venlafaxine granules and assess their formulation variables. It consists of two layers, venlafaxine drug layer and sustained release coating layer and manufactured by fluidized bed process. The sustained release of drug could be increased by double-control rising various components in venlafaxine drug layer and sustained-release layer. The drug-containing granules were coated with cellulose acetate, cetyl alcohol and Eudragit RS along with plastisizer such as dibuthyl sebacate as an nano-pore former The release oi venlafaxine depended on the type of Eudragit such as RS, and RL used in the formulation of controlled release layer. These results obtained clearly suggest that the sustained release oral delivery system for venlafaxine could be designed with satisfying drug release profile approved.

• 약학회지
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• 제44권6호
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• pp.511-520
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• 2000

Various bupivacaine-loaded microspheres were prepared from poly (d,l-lactide) (PLA) or poly (d,l-lactic-co-glycolide) (PLGA) by a solvent evaporation method for the sustained release of drug. PLA and PLGA microspheres were prepared by w/o/w and w/o/o multiple emulsion solvent evaporation, respectively. The effects of process conditions such as emulsification speed, emulsifier type, emulsifier concentration and internal/external phase ratio on the characteristics of microspheres were investigated. The prepared microspheres were characterized for their drug loading, size distribution, surface morphology and release kinetics. Drug loading efficiency was higher in the microspheres prepared by w/o/o multiple emulsion than that by w/o/w multiple emulsion method, because the solubility of bupivacaine HCI was decreased in oil phase compared with water phase. The prepared microspheres had an average diameter between 1 and $2\;{\mu}M$ in all conditions of two methods. In morphology studies the PLA microspheres showed an irregular shape and smooth surface, but PLGA microspheres had a spherical shape and smooth surface. The release pattern of the drug from microspheres was evaluated on the basis of the burst effect and the extent of the release after 24h. The in vitro release of bupivacaine HCl from microspheres showed a large initial burst release and $60{\sim}80%$ release within one day in all conditions of two methods. The extents of the burst release against PLA and PLGA microspheres were $30{\sim}50%$ and $50{\sim}80%$ within 20min, respectively. This burst release seems to be due to the smaller size of microspheres and the solubility of drug in water.

• Journal of Forest and Environmental Science
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• 제34권4호
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• pp.338-351
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• 2018

This study was conducted in a long-term experimental forest in the central hardwoods region of southwestern Michigan to retrospectively examine the role of past forest management practices and climate on red oak (Quercus rubra L.) productivity. Initially, in 1971, plots within the experimental forest were treated separately with a clearcut and shelterwood regeneration harvest in an attempt to increase red oak regeneration. From 1987-1989, a new study was initiated within a portion of the clearcut and shelterwood plots to evaluate the effectiveness of additional oak crop tree release using mechanical and chemical applications. Cumulative diameter and mortality rates of 719 red oaks were monitored across the four silvicultural treatments: Clearcut-A (clearcut without additional release treatment), Clearcut-B (clearcut with additional release treatment), Shelterwood-A (shelterwood without additional release), and Shelterwood-B (shelterwood with additional release) plus an untreated control. Increment cores were obtained from red oak trees and neighboring competitor species. Tree-ring analyses (dendrochronology) were applied to examine the effect of these silvicultural treatments and climatic factors (temperature and precipitation) on red oak productivity. The results indicated that crop tree release following a clearcut or shelterwood harvest reduced mortality rates and thus increased survival of red oak. Red oak in control plots or plots only receiving the initial regeneration harvesting treatment and no additional competition release were negatively affected by climatic stress, which included summer moisture stress. In contrast, red oak in plots that received the competition release treatment from shade tolerant tree species not only had higher tree level productivity (i.e., tree basal area) and lower mortality rates, but were also relatively more resilient to climatic stress by showing limited or no associations between climate and growth.

• 한국토양비료학회지
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• 제35권6호
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• pp.381-386
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• 2002

관행시비 (4회 분시)에 비해 완효성 비료 2회 분시가 수량이 12.5% 증수하였으나, 1회 분시는 $6{\pm}3%$ 감소하였다. 관행시비에 비해 완효성 비료 2회 분시가 총질소, 총 아미노산, 엽록소, 비타민 C 함량과 감칠맛 주성분인 theanine, glutamic acid, arginine 함량이 많았고, tannin 함량은 적은 편이였으나, 완효성 비료 1회 분시는 2회분시와는 반대의 경향을 나타냈다. 형상, 향, 맛 등 제다품질은 완효성 비료 2회분시가 1회분시나 관행 시비 4회 분시에 비해 우수하였다. 결론적으로 완효성 비료의 분시효과가 우수한 이유는 비료성분이 서서히 용출되어 나와 효과적으로 작물에 공급되는 한편 비료성분의 손실을 줄일수 있었기 때문으로 판단된다.

• 한국분말재료학회지
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• 제22권1호
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• pp.21-26
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• 2015

In this study, the control of microstructure for increasing surface roughness of Al with an electro-chemical reaction and a post treatment is systematically investigated. The Al specimen is electro-chemically treated in an electrolyte. In condition of the post treatment at $100^{\circ}C$ for 10 min, a change of the surface microstructure occur at 50V (5 min), and a oxidized layer is at 400V, to which lead a decreasing surface roughness. The minimum temperature of the post treatment for a change of microstructure is $80^{\circ}C$. Moreover, in the condition of 300V (5 min), the electro-chemical reaction is followed by the post treatment at $100^{\circ}C$, the critical enduring time for the change of microstructure is 3 min. The longer post treatment time leads to the rougher surface. The treated Al specimen demonstrate better heat release ability owing to the higher surface roughness than the non-treated Al.