• Journal of the Korean Wood Science and Technology
• /
• 제50권3호
• /
• pp.149-158
• /
• 2022

To realize the infinite possibilities of materials derived from wood, it is necessary to overcome the weak moisture stability of wood. Thus, the development of an eco-friendly hydrophobic coating agent is essential, and of these, woody biomass-based materials are strongly attractive as coatings. In this study, eco-friendly hydrophobic wood coatings were prepared using carnauba wax purified from palm leaves and sprouts, and kraft lignin. The physicochemical properties of the carnauba wax/lignin blends according to the ratio of carnauba wax and lignin were observed by morphology and functional group change. In addition, the coating performance of carnauba wax/lignin blend coatings was confirmed by measuring the contact angle change. It was found that the addition of lignin could accelerate the atomization of wax particles, and that micro-roughness can be realized when applied to the actual wood surface, to ensure that the coating effect over time lasts longer. In addition, it was confirmed that the addition of lignin increases the hydrogen-bond-based interaction with the wood of the coating, thereby providing better coating stability and increasing the durability of the coating solvent under friction. The carnauba wax/lignin paint developed in this way is eco-friendly because all components are made of wood-based raw materials and have an excellent affinity with wood surfaces. Therefore, it is expected to be applicable to the coating process of wood-plastic composites and timber composites.

• 한국직업건강간호학회지
• /
• 제8권2호
• /
• pp.176-192
• /
• 1999

The purpose of this study is to analysis change of industrial health and safety before and after economic crisis(1997~1998). The data were obtained through mail interview with health supervisor(occupational health nurses) during February, 1999. The final sample was consisted of 127 respondents, 97 are selected in this study. The major findings were as follows: First, the percent of industries whose empl safe supervisors, physicians and industry hygi decreased in number is 79.4%, 3.8%, 50.0 21.5% in each. Second, man receiving over 1.5 million won as an average wage of health supervisor is 27.5% in 1997, but it decreased to 25.3% in 1998. Man receiving under 100~150 million won is 48.4% in 1997, but this percent decreased to 36.3% in 1998 and 13.6% of health supervisor regularly were transformed to contingent worker in 1998. Third, especially, budgets for health and saf work place decreased to 13.8% in 1998 than 19. Fourth, industrial accident case, unre accident case, occupational disease decreased than 1997, but mortality from industrial a increased in 250%. Fifth, according to the health diagnosis report, number of case with evidence of disease increased in liver disease, tuberculosis and so on, and number of case with evidence of occupational disease increased in noise induced hearing loss, pneumoconiosis. organic solvent poisoning and so on. Sixth, this survey shows that health council, health education in duty of health supervisor was conducted passive in 1998 thin 1997, and percent of hold two or more positions is 47.6% in medical insurance, 10.7% in accountant's business 8.3 in secretory. 7.1% in telephone operator awl 22.6% in etc. Seventh, distress of health supervisor after economic crisis is 30.9% in employment instability, 19.8% in hold two or more positions and decrease of budgets. For subjugation of the trouble, the respond of active policy of government occupied most.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
• /
• pp.204-204
• /
• 1999

The plasma source ion implantation(PSII) technique which is a method using high negative voltage pulse in plasma system has the potential to change the surface properties of polymer. PSII technique increase the surface free energy by introducing polar functional groups on the surface so that it improves reactivity, hydrophilicity, adhension, biocompatability, etc. However, the mobility of polymer chains enables the modified surface layers to adapt their composition to interfacial force. This hydrophobic recovery interrupts the stability of modified surfaces to keep for the long time. In this study, poly(methyl methacrylate)(PMMA), poly(2-hydroxyethyl methacrylate)(PHEMA), and polu(2-hydroxypropyl methacylate)(PHPMA) for contact lens application, were modified to improve the wettability with PSII technique and were investigated the surface stabilities. Polymer film was prepared with solution casting(3 wt.% solution) and was annealed at 11$0^{\circ}C$ under vacuum oven to remove solvent completely and to eliminate physical ageing. The thickness of the film measured by scanning electron microscopy (SEM) and surface profilometer was about 10${\mu}{\textrm}{m}$. Polymers were treated with different kinds of gases, pulse frequency, pulse with, pulse voltage, and treatment time. Even though PMMA, PHEMA, and PHPMA have similar repeat unit structure, the optimal treatment conditions and the tendency to hydrophobic recovery were different. PHPMA, more hydrophilic polymer than PMMA and PHEMA showd better wettability and stability after mild treatment. Surface tensions were obtained by water and diiodomethane contact angle measurements to monitor the relation between hydrophobic recovery and polymer structure. Different ion species in plasma change the polar component and dispersion component of polymer surface. For better wettability surface, the increase of polar component was a dominant factor. We also characterized modified polymer surfaces using x-ray photoelectron spectroscopy(XPS), secondary ion mass spectrometry(SIMS), Fourier Transform infrared spectroscopy(FT-IR), and SEM.

• 동력기계공학회지
• /
• 제22권6호
• /
• pp.67-73
• /
• 2018

Gasoline that meets the quality standards is distributed in Korea. However, consumers who use toluene or solvent mixed with gasoline have appeared due to rising crude oil prices and for the purpose of tax evasion. Gasoline quality standard is enacted by the domestic and international research reference. A wrong fuel can influence automobile performance or environmental issue. Thus, empirical data from this issue is necessary. Therefore, this research observed catalyst influence by gasoline property change and inspect influence of environment. In this study, fuel property evaluation, lean-burn evaluation, and real vehicle exhaust emission test were performed. In the result of fuel property, the fuel "A" was measured to be up to 27% less octane than the normal gasoline and the distillation property was measured 24% higher than normal gasoline. In the test result of single cylinder engine lean-burn test, the fuels "A" and "B" show torque value 20% less than the normal gasoline. As a result of vehicle test using the catalyst, the fuel "A" was increased more than the normal gasoline with 83% THC, 1,806% CO and 128% NOx, and the fuel "B" was increased more than normal gasoline with 1.6% THC, 391% CO and 142% NOx.

• 융합정보논문지
• /
• 제11권5호
• /
• pp.104-110
• /
• 2021

본 연구는 니파팜의 추출방법에 따른 성분 함량의 변화를 확인하기 위해 수행되어졌다. 니파팜을 에탄올 비율, 추출시간, 추출온도에 따라 추출 후 함량을 분석하였다. 추출용매 비율에 따른 폴리페놀과 플라보노이드의 함량은 50% 에탄올로 추출할 때 각각 36.91, 27.62 mg/g으로 가장 높게 나타났다. 추출온도 및 추출시간에 따른 폴리페놀과 플라보노이드는 60℃에서 6시간 추출 시 각각 40.83, 37.63 mg/g로 가장 높은 함량을 보였다. 니파팜의 주요성분을 에탄올 비율에 따라 함량을 분석한 결과 5-O-caffeoylshikimic acid는 70% 에탄올에서 2.08 mg/g, 4-hydroxybenzoic acid는 30% 에탄올에서 0.10 mg/g, 3,4-hydroxybenzoic acid는 50% 에탄올에서 0.12 mg/g의 가장 높은 함량을 보였다. 추출방법에 따른 니파팜에 함유된 성분의 함량 변화를 통해 식품, 화장품 등 천연물 소재 개발 시 기초 연구 자료로 활용할 수 있을 것으로 기대된다.

• 한국염색가공학회지
• /
• 제2권3호
• /
• pp.36-42
• /
• 1990

The effect of urea and its derivatives, which are known as structure breakers of water, in the dyeing of silk with acid dyes was investigated. Without ureas the maximum dye uptake was observed at $60^{\circ}C$ when dyed with Milling Cyanine 5R, but in the presence of ureas the maximum dye uptake was decreased and its temperature also shifted to lower regin in the order of urea >N-methyl urea > N,N-dimethyl urea>tetramethyl urea. These tendencies were more marked in the dyeing of silk fiber with Orange II, a typical levelling type acid dye. These can be interpreted as the decrease in the hydropholic interaction between fiber molecules which results in the broadening of the inter micelie spacing. The increased partition coefficient of dye molecules in the bath by the action of ureas also contributes to dyeing results, and it can be seen from the spectral characteristics of dyes in aqueous urea solution.

• Bulletin of the Korean Chemical Society
• /
• 제35권6호
• /
• pp.1675-1680
• /
• 2014

A peroxopolyoxotungsten-based ionic hybrid was synthesized by anion-change of peroxopolyoxometalate (POM) $PW_4O{_{24}}^{3-}$ with dicationic long-chain alkyl imidazolium ionic liquids. The characterization was conducted by FT-IR, TGA, $^1H$-NMR and CHN Elemental analyses. Its catalytic performance was evaluated by the epoxidation of soybean oil with $H_2O_2$ under solvent-free condition, including testing of organic cations influence, catalytic reusability and reaction conditions. The catalyst was proved to be a highly efficient recyclable catalyst for epoxidation of various vegetable oils with $H_2O_2$, showing high $H_2O_2$ utilization efficiency, high catalytic activity, convenient recovery and good reuse ability.

• 식품보건융합연구
• /
• 제5권4호
• /
• pp.13-17
• /
• 2019

Amiodarone hydrochloride is an antiarrhythmic agent which has low aqueous solubility and presents bioavailability problem. These properties are a challenge for the pharmaceutical industry. Inclusion of lipophilic compound in the hydrophobic core of micelles, i.e. self-assembled structures based on surfactants in aqueous solution, is one way of increasing the solubility. Intravenous formulation of amiodarone hydrochloride with polysorbate 80 as a detergent and benzyl alcohol as a co-solvent is used in medical practice. This paper aimed to study the effect of polysorbate 80 and benzyl alcohol on the water solubility of amiodarone hydrochloride. Formation of mixed micelles consisting of nonionic surfactant polysorbate 80 and cationic amiodarone with chloride counterion was investigated by fluorescence spectroscopy. Benzyl alcohol was found to decrease the stability of the mixed micelles and lead to crystallization of amiodarone hydrochloride. The greatest amounts of crystals formed at 4℃ for 30 days in the model drug solutions with polysorbate 80 concentrations of 100.1 mg/mL and 97.9 mg/mL. A change of the polysorbate 80 concentration and avoidance the use of benzyl alcohol are recommended to improve the stability of the parenteral dosage form. These results can open new perspectives in the optimization of amiodarone intravenous formulations.

• 한국수산과학회지
• /
• 제23권5호
• /
• pp.401-406
• /
• 1990

In order to assess fish meal as food protein source which contains heat denatured pro-tein, functional properties of fish meal protein to be treated with alkaline were examined. Ratio of fish meal to 0.2N NaOH solution for extract solvent which were 1:10 showed good results of extracted and recovered amount of fish meal protein. pH 4.5, solubility of protein treated with alkaline revealed the lowest value. Until concentrations of alkaline treated protein solution reached $0.7\%$, its emulsifying capacity steeply decreased. Emusifying capacity of alkali treated protein were higher value at pH 9.0 than pH 4.0 and 7.0, and also were higher quantity in 0.5M NaCl solution than that of 0.1M. Heating time of fish meal protein to be treated with alkaline reached until 30 mins, its fat binding capacity indicated little change and that of heating time 60 mins decreased. Gel forming concentrations of fish meal protein to be treated with alkali for 15 mins or less were $20\%$ but those of 30 and 60 mins were $25\%$. When treating time of fish meal protein with alkali solution reached till 20 mins, viscosity of alkali treated protein solution steeply decreased.

• Bulletin of the Korean Chemical Society
• /
• 제13권5호
• /
• pp.486-491
• /
• 1992

The rate constants for the reactions of p-nitrophenyl acetate with 6 different aryloxides and 2 benzohydroxamates have been measured spectrophotometrically in water containing various concentrations of cetyltrimethylammonium bromide (CTAB). The reactivity of the nucleophiles has been demonstrated to be significantly enhanced as the concentration of the surfactant increases up to a certain point. When the basicities of the aryloxides are comparable, the rate enhancement is more prominent for the aryloxide having larger binding constant to the micellar aggregate. Benzohydroxamates exhibitis significantly large ${\alpha}$-effect in the absence of the surfactant, although, the ${\alpha}$-effect nucleophiles are considered to be more solvated in water than the corresponding normal nucleophile. Thus, the solvation effect does not appear to be solely responsible for the ${\alpha}$-effect. Interestingly, the large ${\alpha}$-effect disappears in the presence of the surfactant. Therefore, one might attribute the disappearance of the ${\alpha}$-effect to solvent effect. However, a structural change of the reactive ${\alpha}$ -effect nucleophile into unreactive ones would also be considered to be responsible for the absence of the ${\alpha}$-effect in the present system.