• 대한환경공학회지
• /
• 제38권1호
• /
• pp.34-41
• /
• 2016

UF (ultrafiltration)-SWRO (seawater reverse osmosis) 공정을 이용하여 해수와 기수의 유입수 블렌딩(pre-blending)이 보론(boron)과 휴믹산(humic acid)의 제거에 미치는 영향을 조사하였다. 유입수 블렌딩은 TDS (total dissolved solids) 농도를 기준으로 15,000 mg/L~27,000 mg/L까지 설정하였으며, RO에서의 보론 제거특성을 분석하였다. 또한, 동일한 TDS 농도범위에서 휴믹산을 주입하여 유기물 제거 특성을 알아보았다. 보론은 TDS 농도가 높아질수록 제거율은 76.60% - 83.27%로 높게 나타났지만, 최종 생산된 생산수의 보론 농도는 0.48 mg/L-0.69 mg/L로 높아져 유입수 내 보론 농도가 다량 유입될 시 유입수 블렌딩이 필요할 것으로 판단된다. 휴믹산의 경우 10 mg/L 수준일 경우 TDS 농도 22,500 mg/L가 27,000 mg/L 보다 제거율이 높게 나타났지만, 휴믹산이 5 mg/L 수준일 경우 TDS 농도 18,000 mg/L가 15,000 mg/L보다 높게 나타났다. 한편, 휴믹산이 주입되었을 때 UF-SWRO 공정에서는 오히려 플럭스(flux)와 회수율(recovery rate)이 증가하는 효과를 나타내었는데, 이는 파울링 물질이 $Ca^{2+}$와 휴믹산의 결합에 의해 대부분 제거되어 나타난 것으로 판단된다. 따라서 UF-SWRO를 이용한 해수 담수화 시 보론 농도와 휴믹산 제거측면에서 TDS 농도가 낮을수록 유리하다고 판단된다.

• 센서학회지
• /
• 제9권2호
• /
• pp.134-140
• /
• 2000

Si기판 직접접합기술은 전자소자 및 MEMS에의 응용에 있어 대단히 매력적인 기술이다. 본 논문에서는 Si기판 직접접합에 있어서 HF 전처리 조건에 따른 초기접합에 관하여 서술한다. 접합된 시료들의 특성은 HF 농도, 인가하중과 같이 각각의 접합조건하에서 분석하였으며, 접합력은 인장강도측정법에 의해 평가하였다. 계면상의 결합성분과 표면의 거칠기는 FT-IR과 AFM을 사용하여 평가하였다. HF 전처리 후 Si기판 표면상의 Si-F결합은 DI water에 세정하는 동안 Si-OH로 재배열되며, 결과적으로 hydrophobic 기판은 Si-OH$\cdots$(HOH$\cdots$HOH$\cdots$HOH)$\cdots$OH-S의 수소결합되어 hydrophilic화된다. 초기접합력은 초기접합전의 HF 전처리 조건에 의존한다. (최소 : $2.4kgf/cm^2{\sim}$최대 : $14.9kgf/cm^2$)

• 신재생에너지
• /
• 제10권1호
• /
• pp.20-29
• /
• 2014

The present study investigated the effects of thermal pre-treatment on the enhancement of anaerobic biodegradability of waste activated sludge at varied TS concentration levels. The activated sludges were thermally oxidized for 30 minutes at $80{\sim}200^{\circ}C$ with varied TS concentrations (2%, 4% and 6%). and then, sludge characteristics, solubilization efficiency and methane production yield of thermally pre-treated sludges were analyzed. The higher the temperature in the thermal pre-treatment, the higher the concentration levels of dissolved matters such as $SCOD_{Cr}$, $NH_4{^+}$ and VFAs, which indicates that the thermal pre-treatment facilitates the hydrolysis and acid fermentation. Furthermore, the solubilization efficiency was increased in proportion to the temperature rise at all TS concentrations and was reached at 68.9%, 55.6% and 53.1%, respectively, at $200^{\circ}C$. In the BMP test of the pre-treated sludges, higher methane production yields were observed as 0.313. 0.314 and $0.299m^3\;CH_4/kg\;VS_{add}$ at the condition of TS 2% ($160^{\circ}C$), 4% ($160^{\circ}C$) and 6% ($180^{\circ}C$), respectively, and degradation rate was increased by 84%, 79% and 65% compared with non-pretreated waste activated sludge. These findings suggest the effectiveness of thermal pre-treatment of waste activated sludge for anaerobic biodegradable process.

• Journal of Nutrition and Health
• /
• 제36권10호
• /
• pp.1036-1041
• /
• 2003

Ecological studies have indicated that the essential fatty acids in maternal and umbilical cord blood samples are associated with gestational length and birth weight. The objectives of this study were to examine serum fatty acid concentration, particularly $\omega$3 fatty acids, in maternal and umbilical cord blood and to investigate the relationship of serum fatty acid levels in the blood of the mother and of the umbilical cord. Subjects consisted of 30 full-term and 30 pre-term mothers and neonates of both groups. Serum levels of fatty acids were measured by gas chromatography. The concentration of total saturated fatty acids in pre-term pregnant women was significantly higher than that of the full-term group (p<0.05), however, the maternal level of $\omega$3 fatty acids in the pre-term group was significantly lower than that of the full-term pregnant women (p<0.05), Moreover, the concentrations of $\alpha$-linolenic acid and eicosapentaenoic acid in full-term pregnant women were significantly higher than those of the pre-term group. In umbilical cord blood, the levels of total $\omega$3 fatty acid and arachidonic acid were significantly lower in the pre-term group than in the full-term group (p<0.05). Based on the coefficient of correlation between serum fatty acids in the mother and the umbilical cord, it turned out that in the full-term group, the newborn's umbilical cord serum fatty acids were not influenced by the levels of serum fatty acids in the mother. However, in the pre-term group, it seems to have positive correlations in terms of the levels of SFA, MUFA, PUFA and $\alpha$-linolenic acid. This study suggests that a lower status of $\omega$3 fatty acids in maternal and umbilical cord blood probably is a risk factor for pre-term birth.

• 한국지역사회생활과학회지
• /
• 제16권1호
• /
• pp.65-72
• /
• 2005

To increase dyeability of cotton fabric to the chestnut shell dyeing, we had several dyeing experiments with the experimental fabrics which was pre-treated by soybean, NaOH, KOH. Three kinds of experimental cotton fabrics were used and chestnut shell dyebath was made for the experiment. Munsell's color HV/C and color differences ΔE of dyeing fabrics were compared between pre-treatment and none pre-treatment dyeing fabrics. The main results were as follows ; Color differences of dyeing fabrics pre-treated with soybean, NaOH, KOH were higher than those of none pre-treated dyeing fabrics. In case of pre-treatment with soybean, the concentration of the soybean bath affected the color differences but not affected in case of pre-treatment with NaOH & KOH. Munsell's color of pre-treatment fabrics with soybean, NaOH, KOH were same with the none pre-treatment fabrics. Colorfastness of the pre-treated fabrics were same degree, but only in case of soybean pre-treated fabrics were low in fastness of washing(change) & perspiration(acidic change).

• 한국의류산업학회지
• /
• 제8권4호
• /
• pp.476-480
• /
• 2006

For the purpose of application to new natural dyestuff, the dyeability of Rubus coreanus Miquel extract was analyzed. It was dyed in silk fabric according to various dye concentration, dyeing temperature, dyeing time, and dyeing repetition. And the effects of mordanting conditions were examined as color differences and color fastnesses. The maximum absorbance of Rubus coreanus Miquel extract was at 521 nm. The dyeaffinities were increased gradually as were increased dye concentration, dyeing temperature, dyeing time, and dyeing repetition. The dyeaffinity was increased at pre-mordanted condition, and color difference was increased distinctly at post mordanted condition. The hues of mordanted silk fabrics were RP, P, PB, BG where as non mordanted silk fabric was R. Lightfastness was the best at pre-Sn mordanted and the worst at Post-Al mordanted. Washing and perspiration fastnesses were improved on pre and post-Sn mordanted.

• 한국세라믹학회지
• /
• 제47권3호
• /
• pp.244-248
• /
• 2010

Porous calcium phosphates were successfully fabricated by using a cuttlefish bone. The cuttlefish bone, which is composed of $CaCO_3$, showed a special porous microstructure containing uniform-sized voids. In this study, the pre-forms infiltrated distilled phosphoric acid were sintered at $1200^{\circ}C$ in an air atmosphere. The porous microstructure of the pre-forms was kept their original pattern after sintering with a synthesis of calcium phosphate. The obtained porous calcium phosphate, sintered at $1200^{\circ}C$ for 3 h at 17% concentration of phosphoric acid, showed uniform open pores of 150 ${\mu}m$ in size and $\beta$-TCP phase in the XRD patterns. Above 16% concentration, CaO phase, derived from the decomposition of $CaCO_3$, decreased gradually in the sintered samples, and the measured Ca/P ratios of the samples prepared from 16% and 18% concentration were 1.67 and 1.43, which are close to stoichiometric HA (1.66) and $\beta$-TCP (1.50).

• Animal cells and systems
• /
• 제1권1호
• /
• pp.87-91
• /
• 1997

Effects of divalent cations such as $Mg^{2+}$, $Mn^{2+}$, $Ca^{2+}$, and $Zn^2$ on splicing activity of phage T4 thymidylate synthase intron RNA have been investigated. At the concentration of 0.5 mM, $Mn^{2+}$ in the absence of $Mg^{2+}$, a very small amount of pre-RNA was cleaved into ligation products (El-E2) but no circular or linear intron was produced. As the concentration of $Mn^{2+}$ was increased from 1 to 5 mM the pre-RNA was completely hydrolyzed. In the presence of 5 mM $Mg^{2+}$, both the linear intron and circular intron were produced but no El-E2 ligation product was produced. At both 3 and 5 mM $Mn^{2+}$ the RNA was hydrolyzed completely as observed with no $Mg^2+$ being present. In the case of $Zn^{2+}$, even at 0.5 mM concentration, the pre-RNA was completely hydrolyzed. This observation suggested that $Zn^{2+}$ facilitates RNA hydrolysis more rapidly than $Mn^{2+}$ does. at 5mM $Ca^{2+}$, the RNA was not hydrolyzed and remained intact as a primary transcript.

• 한국염색가공학회지
• /
• 제30권4호
• /
• pp.294-303
• /
• 2018

In this study, eco-friendly natural dyeing for pig leather was explored by using onion skin which is food waste. Sodium caseinate was used as a pre-treatment agent to improve dyeability of pig leather and its effect on dye uptake was investigated according to treatment concentration. Dye uptake of the pre-treated pig leather was increased by about two times compared to untreated one at 0.2% pre-treatment concentration. Onion skin colorant imparted YR color on pig leather. After mordanting, the color of pretreated/dyed pig leather was varied from brick-red to khaki shades. However, mordanting did not improved dye uptake of the pre-treated/dyed pig leather significantly. The color-fastnesses of un-mordanted samples to light, dry cleaning, rubbing were grades 3-4, 5, and 4, respectively, which is good enough to meet all Korean Standard for Fastness of leather products. After mordanting, the light fastness of pig leather was improved to 4, 4-5 grade. The efficacy of sodium caseinate as a pre-treatment agent for pig leather was verified by improved dye uptake and good colorfastness. And, the natural dyeing of pig leather using food waste would be a significant sustainable way in terms of eco-friendliness and reuse of biomass to reduce environmental pollution.

• International Journal of Oral Biology
• /
• 제40권4호
• /
• pp.183-187
• /
• 2015

The present study was aimed to evaluate the influence of glutaraldehyde (GA) concentration on multiple electron microscopic (EM) immunostaining using pre-embedding peroxidase and post-embedding immunogold method. Influence of various concentrations of GA included in the fixative on immuoreactivity was assessed in the multiple immunostaining using antisera against anti-transient receptor potential vanilloid 1 (TRPV1) for peroxidase staining and anti-GABA for immunogold labeling in the rat trigeminal caudal nucleus. Anti-TRPV1 antiserum had specificity in pre-embedding peroxidase staining when tissues were fixed with fixative containing paraformaldehyde (PFA) alone. Immunoreactivity for TRPV1 was specific in tissues fixed with fixative containing 0.5% GA at both perfusion and postfixation steps, though the immunoreactivity was weaker than in tissues fixed with fixative containing PFA alone. Tissues fixed with fixative containing 0.5% GA at the perfusion and postfixation steps showed specific immunogold staining for GABA. The results of the present study indicate that GA concentration is critical for immunoreactivity to antigens such as TRPV1 and GABA. This study also suggests that the appropriate GA concentration is 0.5% for multiple immunostaining with peroxidase labeling for TRPV1 and immunogold labeling for GABA.