• 에너지공학
• /
• 제17권1호
• /
• pp.38-45
• /
• 2008

본 연구는 캐나다산 아사바스카 오일샌드 역청(Athabasca Oilsands Bitumen)의 용매 불용분 실험(Solvent-Insolubles Experiment)을 통하여 아스팔텐(Asphaltenes : Solvent-Insolubles) 및 말텐(Maltenes : Solvent-Solubles)에 대한 다양한 물리 화학적 특성변화를 살펴보기 위하여 수행되었다. 용매는 n-Heptane, n-Hexane, n-Pentene의 3가지 용매를 사용하였고, 아스팔텐의 분리는 ASTM D 3279 방법을 응용하여 실시하였다. 역청, 아스팔텐, 말렌에 대한 분석항목은 원소분석, 분자량 분포, 비점 분포, 중금속 함량, API 비중, 점도, SARA 분포 등이다. 분석 결과 모든 말텐의 황 함량, 중금속 함량 및 분자량은 역청에 비하여 낮은 경향을 보였다. 그리고 n-Pentane 용매를 사용한 경우가 다른 용매에 비하여 말텐의 점도가 감소하였고, 황, 중금속 함량 및 분자량도 상대적으로 낮게 측정되었다. 따라서, 본 실험결과는 합성원유(SCO) 생산을 위한 역청의 경질화 공정에 필요한 기초자료로 활용할 수 있다고 판단된다.

• 한국생활과학회지
• /
• 제21권5호
• /
• pp.989-1004
• /
• 2012

The purpose of this study was to investigate the characteristics of the pigment and the dyeability of juniperus chinensis needles, berry, bark and heartwood extracts using distilled water, methanol, normal butanol and ethyl acetate as a solvent. Ultraviolet-visible absorption spectrum bands of the extracts were measured at around 280nm to 320nm in all the solvent extracts. The maximum absorption wavelength was able to determine tannin. All the solvent extracts except for distilled water extracts were able to confirm the presence of chlorophyll. Infrared absorption spectra (FT-IR) of all parts of the extracts showed broad absorption bands of OH due to phenolic-OH, benzene CH peak of phenol chemical structure, ether-based stretching vibration peak and the peak of flavonoid compounds that appeared in all the solvent extracts. The yield of juniper needles and heartwood in distilled water and methanol extraction were effective. Extraction of berry yields in distilled water was also effective. The yield of ethanol extraction from the bark showed better efficiency. As a result of using distilled water for the dye solution, the color of the fabrics dyed with all extracts of the needles and Y series berries generally showed light Y progression with a strong red tinge. By using a mixture of 20% ethanol and 80% distilled water for the dye solution, the color of the fabrics dyed with needles and berry extracts showed Y series dominantly. The color of the fabrics dyed with Bark and heartwood extracts were dominantly R series.

• 한국산학기술학회논문지
• /
• 제16권8호
• /
• pp.5721-5727
• /
• 2015

페인트는 외부로부터 본체가 손상되는 것을 막아주며, 오랫동안 색깔과 마무리 상태를 유지해 준다. 유기용제와 물이 페인트의 용제로 사용되고 있으며, 유기용제는 VOCs의 인위적인 공급원으로 알려져 있다. 이러한 이유로 자동차 내장부품에서 유기용재 페인트의 사용은 줄어들고 있으며, 외장 부품에서는 계속 사용하고 있다. 수성페인트의 접착력은 유성페인트에 비하여 작아, 페인트가 기제로부터 박리되고 있어, 품질문제를 일으킨다. 본 연구에서는 수성페인트와 실린 혼합물의 접착 특성에 대하여 연구하였다. 수성페인트의 접착력을 향상시키기 위하여 접착제와 혼합이 필요하다. 접착력은 UTM을 이용하여 ASTM D1002 방법으로 측정하였고, 박리현상은 ASTM D1002를 사용하여 측정하였다. 수성페인트와 실란접착제의 최적 혼합조건은 $25^{\circ}C$, 500rpm, 20분 이었으며. 실란접착제 농도는 5wt% 이었다

• Archives of Pharmacal Research
• /
• 제23권4호
• /
• pp.385-390
• /
• 2000

To demonstrate the effect of formulation conditions on the controlled release of protein from poly(lactide-co-glycolide) (PLGA) microspheres for use as a parenteral drug carrier, ovalbumin (OVA) microspheres were prepared using the W/O/W multiple emulsion solvent evaporation and extraction method. Methylene chloride or ethyl acetate was applied as an organic phase and poly(vinyl alcohol) as a secondary emulsion stabilizer. Low loading efficiencies of less than 20％ were observed and the in vitro release of OVA showed a burst effect in all batches of different microspheres, followed by a gradual release over the next 6 weeks. Formulation processes affected the size and morphology, drug content, and the controlled release of OVA from PLGA microspheres.

• 약학회지
• /
• 제39권6호
• /
• pp.593-599
• /
• 1995

Erythromycin was formulated as enteric-coated pellets in order to reduce degradation in stomach and gastromtestmal irritation, and to maximize the absorption in intestine followmg its oral administration. Core pellets were prepared using fluid-bed granulator with two different methods (powder layering and solvent spraying) and enteric-coated with two different coating polymers (HPMCP and Eudragit E30D). Physical characteristics md dissolution rates of core pellets and enteric-coated pellets were evaluated to optimize the formulation. Powder layering method resulted in shorter initial dissolution time than solvent spraying method, but physicochmical properties of the product were worse than solvent spraying method with respect to hardness, ftiability and density. The dissolution rate of the drug was increased with the addition of surfactants, showing concentration-dependence. The scanning electron microscopic observation of pellets revealed significant differences on the surface appearances prepared with solvent spraying method. The core pellet made with powder layering method had crystals on the surface, which resulted in poor physical properties of the pellets. The dissolution profiles of erythromycin pellets coated with HPMCP or Eudragit L30D were close to that of commercially available erythromycin enteric-coated product.

• 한국염색가공학회지
• /
• 제15권3호
• /
• pp.146-153
• /
• 2003

This article describes the metal ions adsorption of chitosan fibers. The chitosan fibers were manufactured by wet spinning using 2% acetic acid as solvent, 10% aqueous sodium hydroxide as non solvent, and 4%chitosan solution as a solvent. The adsorption characteristics of chitosan fibers towards 100ppm solutions of various metal ions such as Cu(II), Cd(II), Cr(III), Hg(II) were examined at different pH value by ICP-Atomic Emission Spectrometer. The adhesiveness of metallic ions to the chitosan fiber were increased with the increase of pH and the decrease of denier. On the other hand, from pH4, chitosan fiber that is immersed in metal ion aqueous solution of Cu(II) and Cd(II) became homogeneous solution because is dissolved. The adhesiveness of metallic ions to chitosan fiber were found to increased in a sequence of Hg(II)> Cr(III)> Cu(II)> Cd(II). The antimicrobial characteristics of the chitosan fiber by adhered metal ions, virgin chitosan fiber, and cotton fiber were evaluated. The antimicrobial activity of the fibers were increased with the decrease of denier.

• 펄프종이기술
• /
• 제39권3호
• /
• pp.70-76
• /
• 2007

The raw oriental lacquer produced in China was used in this study. This lacquer was diluted with ethanol and terpene in different solvent ratios. The diluted lacquer in the solvents had two layers. The upper layer was solvent soluble and the lower contained precipitates. Hanji was treated with the solvent solubles and the mixture containing precipitates, and then properties of the Hanji were evaluated. The average weight, thickness, and density of Hanji treated with oriental lacquer tended to gradually be decreased as the lower concentration of lacquer was used and as the solvent soluble was treated. Tensile strength of the treated Hanji decreased when the diluted lacquer was used and Hanji treated with terpene dilution at the ratio of lacquer to solvent of 1:5 (v/v) showed higher tensile strength than ones treated with ethanol dilution. The folding endurance decreased as the less concentrated lacquer was used and the highest value was obtained when 1:40 (v/v) of lacquer to solvent ratio in both ethanol and terpene mixture. Absorption ratio was higher in the Hanji treated with ethanol mixture, treated with the lacquer in lower concentration, and treated with ethanol mixture. Hanji treated with ethanol dilution at 1:20 (v/v) and the lower ratio of lacquer to solvent showed a hydrophobic property. Amount of the bound dye materials tended to be decreasing as the concentration of lacquer became lower and it was higher in Hanji treated with ethanol mixture than with terpene mixture.

• 한국산업보건학회지
• /
• 제29권4호
• /
• pp.488-499
• /
• 2019

Objectives: This study was conducted to identify the characterization of organics solvent exposure among painting workers in the shipbuilding painting process, especially for their daily variations(within worker variance). Methods: Charcoal passive dosimeters were worn throughout each work shift for 20 days for five painting workers from October 19 to November 26, 2015. A total of 100 samples were collected, analyzed and compared with statutory workplace environmental measurements. Results: The geometric mean(GM) and geometric standard deviation(GSD) of mixed organic solvent(six substances) exposure index(EI) for the 100 samples were 0.42 and 4.42 respectively. The median and range of GSD for within worker EI representing five workers' daily EI variation is 3.72 and 2.63 ~ 5.20, respectively, which is classified as a very large variation(GSD>3). We were able to divide the painting process into two similar exposure groups(SEGs), Touch-up and Spray. Spray painting workers were much more exposed to organic solvent than Touch-up painting workers(GM=0.71 vs. 0.19), but less variably (GSD=3.64 vs. 4.10). xylene is the substance to which the workers were most exposed(GM=16.19 ppm, GSD=4.36), and the exposure characteristics of six substances including xylene is similar to those of EI. Conclusions: The daily variation of organic solvent exposure in the shipbuilding painting process is so high that statutory Assessment of Reliability of Work Environment Monitoring needs to be conducted with statistically sufficient number of samples and evidence.

• Journal of Electrochemical Science and Technology
• /
• 제14권3호
• /
• pp.262-271
• /
• 2023

For electrode stability and the electrochemical performance of the Li-ion cell, it is essential that the active ingredients and unique additives in the polymer binder be well dispersed with the solvent-based slurry. The efficient procedure used to create the slurry affects the rheological characteristics of the electrode slurry. When successively adding different steps of Nmethyl-2-pyrrolidone (NMP) solvent to the cathode composition, it is evenly disseminated. The electrochemical performance of the Li-ion cells and the electrodes made with slurry formed by single step and multiple steps of addition of NMP solvent are examined. To preform rheological properties of cathode electrode slurry on Ni-rich Lithium Nickel-Cobalt-Aluminum Oxide (LiNi_0.80Co_0.15Al_0.05) (NCA). Also, we investigate different step addition of electrode formation and mechanical strength characterization like peel strength. According to the EIS study, a multi-step electrode slurry has lower internal resistance than a single-step electrode slurry, which results in better electrical characteristics and efficiency. Further, microstructure of electrodes is obtained electrochemical performance in the 18650 cylindrical cells with targeted capacity of 1.5 Ah. The slurry of electrodes prepared by single step and multiple steps of addition of NMP solvent and its effect on the fabrication of 1.5 Ah cells. A three-step solvent addition on slurry has been found to be a lower internal resistance than a single-step electrode slurry as confirmed by the EIS analysis, yielding improved electrical properties and efficiency.

• 한국염색가공학회지
• /
• 제29권3호
• /
• pp.105-114
• /
• 2017

High tenacity polyethylene(HTPE) fiber is one of the most important synthetic fibers which possesses outstanding properties such as low density, excellent surface hardness and scratch resistance, superior electrical insulation and low cost. In this study, we dyed high tenacity polyethylene filaments using three different solvent dyes based on log P calculations. We evaluated the dyeing characteristics of dyed high tenacity polyethylene filaments based on dyeing temperature, dyeing time and concentration of solvent dyes. We also analyzed the tensile strength and elongation properties of dyed high tenacity polyethylene filaments with various dyeing temperature and dyeing times. The optimized dyeing condition can be found at $120^{\circ}C$ for dyeing time of 1 hour with 4%(o.w.f.) of solvent dyes.