• Analytical Science and Technology
• /
• v.15 no.4
• /
• pp.329-334
• /
• 2002

Tributyl phosphate(TBP) is used in solvent extraction process for radioactive waste. This compound may be degraded to dibutyl phosphate($DBP^-$), monobutyl phosphate($MBP^{2-}$) and ${PO_4}^{3-}$ by radioactive material. Amount of $DBP^-$ and $MBP^{2-}$ in TBP must be monitored because they production of these compounds means degradation of which leads to a decrease in the extraction yield. Retention behavior for $DBP^-$, $MBP^{2-}$, $F^-$, $Cl^-$, ${NO_2}^-$, ${NO_3}^-$, ${SO_4}^{2-}$ and ${PO_4}^{3-}$ are studied with AS4A-SC(Dionex) analytical column and $Na_2CO_3$/NaOH eluent by Ion chromatography. Optimum condition for these anions is 2 mM $Na_2CO_3$/1 mM NaOH eluent. All anions by this condition is well separated within 15min. Dynamic range is $10{\mu}g/mL$ - $100{\mu}g/mL$ for DBP and $5{\mu}g/mL$ - $50{\mu}g/mL$ for $MBP^{2-}$, respectively. The Detection limit for AS4A-SC are $1{\mu}g/mL$ for $DBP^-$ and $0.5{\mu}g/mL$ for $MBP^{2-}$ in this system with a $25{\mu}L$ sample loop.

• Textile Coloration and Finishing
• /
• v.32 no.2
• /
• pp.111-120
• /
• 2020

In this study, lignin/chlorinated poly(vinyl chloride)(CPVC) blended fibers have been produced for the development of low-cost carbon fiber. Carbon fiber manufacturing was accomplished through stabilization and carbonization process. The lignin/CPVC blended fibers were prepared by wet spinning method. Dimethylacetamid e(DMAc) and cychlohexanone in a ratio of 5:1(wt%) was employed as co-solvent. The ratio of lignin/CPVC was prepared at 0/10, 1/9, 2/8, 3/7, 4/6, and 5/5(wt%). The spinning solution was extruded at a rate of 0.1 to 0.4ml/min according to the blending ratio. The speed of the rollers was the same for all ratios(draw ratio=1). Analysis of fiber cross-section by scanning eletron microscopy(SEM) showed that as the lignin ratio increased in the same coagulation bath and distilled water, the pore size of the spinning fiber decreased. Therefore, the highest tensile strength of the blending fibers was 6.3±1.2MPa at the 5/5 ratio. The carbon fiber also showed the best tensile strength of 120.78±2.43MPa at 5/5 ratio.

• Applied Chemistry for Engineering
• /
• v.8 no.2
• /
• pp.220-229
• /
• 1997

Extraction of valuable light hydrocarbon from atmospheric residue using pentane as a solvent has been carried out. The SIMDIS was used to calculate the true boiling point of atmospheric residue containing complex components before the modeling of the extraction process could by performed. In order to simplify the procedure, modeling was adopted and a lumping method was used, such that a large number of compounds were divided into similar component classes called pseudocomponents. The modeling of the extraction process of the atmospheric residue-pentane system was based on the isothermal flash calculation, and the Peng-Robinson equation of state was used to calculate the fugacity coefficient of vapor and liquid phase during calculation steps of modeling. The agreement between the experiments and the calculations was reasonable considering the uncertainties involved in modeling such complex processes.

• Current Photovoltaic Research
• /
• v.10 no.4
• /
• pp.101-106
• /
• 2022

We prepared a CsPbI₂Br solution using Cesium iodide (CsI), Lead (II) bromide (PbBr₂) and Lead (II) iodide (PbI₂) materials into a polar solvent mixture of N,N-dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO). A simple spin coating technique was used for the fabrication of CsPbI₂Br absorber layer in the solution process. In order to prepare uniform coating of absorber film we adopted a hot-air process in assocation with the spin coating. It was confirmed that the thin film manufactured by the hot-air process had a higher absorption rate than that without it, and the optical band gap was measured 1.93 eV. The thin film of absorber was uniformly prepared and revealed the Black α-Cubic crystal phase as proved through X-ray diffraction analysis. Finally, a perovskite solar cell having an n-i-p structure was manufactured with a CsPbI₂Br perovskite absorption layer. From the solar cell, we obtained a power conversion efficiency (PCE) of 5.97% in a forward measurement.

• KSBB Journal
• /
• v.21 no.4
• /
• pp.312-316
• /
• 2006

A optimal condition for the Ginkgo biloba extraction in ethanol and water binary solvent system has been proposed based on concentration of bilobalide and ginkgolide known as having a antimicrobial components in the range 5% to 70% ethanol in water at $80^{\circ}C$. Concentration of bilobalide as a single component of Ginkgo biloba leaves extract is the highest at the 60% ethanol and ginkgolide A and B is highest at 50% ethanol. Antimicrobial effect of Ginkgo biloba leaves extracts on the S. aureus was also examined by disc diffusion test and optical density test. In case of the disc diffusion test, the clean zone diameter was increased from 0.95 cm to 1.70 cm as ethanol concentration increased from 5 to 70%. However, over the 40% of ethanol concentration the antimicrobial effect was almost flat. Based on these results, we propose that the 40% of ethanol and 60% water solvent is most desirable for Ginkgo biloba extract considering vapor pressure problem in concentrating process after extraction. We introduced SEM and TEM to figure out the morphological change on the surface and inside body of S. aureus when Ginkgo biloba leaves extract was treated. After mixed with Ginkgo biloba leaves extract blast like blebs appeared on the surface of S. aureus cells and cell wall was not observed. From the these results, it seems that the Ginkgo biloba leaves extract including bilobalide and ginkgolide A, B prevent cell wall synthesis.

• Polymer(Korea)
• /
• v.36 no.1
• /
• pp.98-103
• /
• 2012

Poly(2,6-dimethyl-1,4-phenylene ether) (PPE) was synthesized using $Cu(NO_2)_2{\cdot}3H_2O$ or CuCl catalyst with various amounts of ligand and base in several different solvent systems. CuCl/1-methylimidazole/ammonium hydroxide was found to be an effective catalyst system which showed the highest polymer yield and molecular weight. The effects of catalyst/monomer ratio, different amine ligands, and the content of mono-functional reagent 2,4,6-trimethylphenol (TMP) additive on the polymer yield and molecular weight were investigated. Among the co-solvent systems used in this polymerization, chloroform/methanol 9/1(v/v) gave the highest polymer yield and molecular weight ($\overline{M_n}$ 55 K, $\overline{M_w}$ 92 K, PDI 1.7). The catalytic activity between CuCl and CuI was compared by oxygen-uptake experiments and the formation of sideproduct, 5,5'-tetramethyl-4,4'-diphenoquinone (DPQ), was analyzed by ultraviolet spectroscopy.

• Proceedings of the Ginseng society Conference
• /
• 2002.10a
• /
• pp.491-501
• /
• 2002

A cross-examination between KT&G Central Research Institute and Guangzhou Institute for Drug Control was carried out in order to select optimum conditions for extraction, separation and determination of ginsenosides in red ginseng and to propose a better method for the quantitative analysis of ginsenosides. The optimum extraction conditions of ginsenosides from red ginseng were as follows: the extraction solvent, $70\%$ methanol; the extraction temperature, $100^{\circ}C;$ the extraction time, 1 hour for once; and the repetition of extraction, twice. The optimum separation conditions of ginsenosides on the SepPak $C_{18}$ cartridge were as follows: the loaded amount, 0.4 g of methanol extract; the washing solvents, distilled water of 25 ml at first and then $30\%$ methanol of 25 ml; the elution solvent, $90\%$ methanol of 5 ml. The optimum HPLC conditions for the determination of ginsenosides were as follows: column, Lichrosorb $NH_2(25{\times}0.4cm,$ 5${\mu}m$, Merck Co.); mobile phase, a mixture of acetonitrile/water/isopropanol (80/5/15) and acetonitrile/water/isopropanol (80/20/15) with gradient system; and the detector, ELSD. On the basis of the optimum conditions a method for the quantitative analysis of ginsenosides were proposed and another cross-examination was carried out for the validation of the selected analytical method conditions. The coefficient of variances (CVs) on the contents of ginsenoside-$Rg_{1}$, -Re and $-Rb_1$ were lower than $3\%$ and the recovery rates of ginsenosides were $89.4\~95.7\%,$ which suggests that the above extraction and separation conditions may be reproducible and reasonable. For the selected HPLC/ELSD conditions, the CVs on the detector responses of ginsenoside-Rg, -Re and $-Rb_1$) were also lower than $3\%$, the regression coefficients for the calibration curves of ginsenosides were higher than 0.99 and two adjacent ginsenoside peaks were well separated, which suggests that the above HPLC/ELSD conditions may be good enough for the determination of ginsenosides.

• Journal of Dairy Science and Biotechnology
• /
• v.34 no.2
• /
• pp.91-98
• /
• 2016

The goal of this study was to develop hydrolyzed whey protein powder (23%-GNANA) manufactured with high content of sialic acid, a marker compound that is usually present at 7% concentration in GMP obtained from the milk protein. It is a safe food, used worldwide in infant and baby foods, etc. The test substance was prepared using (7% sialic acid containing) GMP as a raw material. Alcalase, an enzyme approved as a food additive, was used after separating sialic acid, with 100% efficiency, and 23%-GNANA (composed of 23% sialic acid and protein; product name: HELICOBACTROL-23), provided by MEDINUTROL Inc. (Korea), manufactured to have high (23%) content through ethanol soaking and enrichment. Bacterial reverse mutation (Ames) test was conducted in accordance with the GLP Guideline using the test substance specified above. To detect its mutagenicity potential in microorganisms, histidine auxotrophic strains of Salmonella typhimurium, TA98, TA100, TA1535, and TA1537, and tryptophan auxotrophic Escherichia coli strain, WP2uvrA, were used. The bacterial reverse mutation (Ames) test was performed using five concentrations of the test substances (0, 61.7, 185, 556, 1,670, $5,000{\mu}g/plate$). The evaluation did not reveal repetitive increase of colony generating values and positive criteria for reverse mutagenicity for any tested concentration in the five strains regardless of the presence of metabolic activation system, and no dose-dependency. In conclusion, the safety of 23%-GNANA test substance was verified by the bacterial reverse mutation test conducted before registration of 23%-GNANA as a food additive.

• Applied Chemistry for Engineering
• /
• v.25 no.5
• /
• pp.503-509
• /
• 2014

The carbon/porous silica composite membrane was fabricated in a simple manner, which could be successfully for the simultaneous separation and production of chiral epoxides and 1,2-diols, based on their differences in hydrophilic/hydrophobic natures. The chiral Co(III)-$BF_3$ salen catalyst adopted in the membrane reactor system has given the very high enantioselectivity and recyclability in hydrolysis of terminal epoxides such as ECH, 1,2-EB, and SO. The optically pure epoxide and the chiral catalyst were collected in the organic phase after hydrolysis reaction. The hydrophilic water-soluble 1,2-diol product hydrolyzed by chiral salen diffused into the aqueous phase through the SBA-16 or NaY/SBA-16 silica composite layer during the reaction. The water acted simultaneously as a reactant and a solvent in the membrane system. One optical isomer was obtained with high purity and yield, and furthermore the catalysts could be recycled without observable loss in their activity in the continuous flow-type membrane reactor.

• Journal of the Korean Applied Science and Technology
• /
• v.29 no.3
• /
• pp.486-494
• /
• 2012

Nano-emulsion with phase inversion temperature (PIT) emulsifying system was prepared to use rapeseed oil from originating Jeju in order to apply various cosmetic applications. Natural rape seed oil (NRSO) extraction was extracted using n-hexane as a solvent. NRSO extract showed a light yellowish color of viscous liquid as well as yield was $43{\pm}2.5%$. Acid value was $2.76{\pm}0.5$ and gravity was $0.89{\pm}0.05$. Droplet size of PIT-Yuche-NE with 20wt% of rapeseed oil was 50-120nm (average: $82{\pm}5.8nm$) and zeta potential was -29.5mV. It was thermodynamically good stable emulsion due to $(PEG)_{5-30}$fattyacidether. Some conclusions from the result of characteristic experiment were obtained as follows. First, the anti-oxidative activity was measured by free radical scavenging activity using DPPH (1,1-diphenyl-2-picrylhydrazyl radical). Anti-oxidative activity of PIT-Yuche-NE was $37.2{\pm}6.7%$ on 10mg/mL compared with PIT-Toco-NE (Natural tocopherol nano-emulsion, $28.8{\pm}6.5%$ on 10 mg/mL) and PIT-Nokcha-NE (Green tea extract nano-emulsion, $29.6{\pm}7.2%$ on 10mg/mL). Second, the collagen synthesis activity of PIT-Yuche-NE was $148{\pm}15.2%$ compared with PIT-Toco-NE (Natural tocopherol nano-emulsion, $121{\pm}13.5%$ on 10mg/mL) and PIT-Nokcha-NE (Green tea extract nano-emulsion, $95{\pm}12.7%$ on 10mg/mL). Third, the effectiveness of moisturizing activity of Yuche-CRM with Aramo-TS after 6 hours increase $47{\pm}3.9%$ (*p-value￡0.05, n=7) whereas Both Toco-CRM was $30{\pm}5.2%$ (*p-value￡0.05, n=7) and Nokcha-CRM was $35{\pm}4.5%$. Therefore, Yuche-CRM has higher moisturizing effect than other two creams. Finally, Nano-emulsion stabilizing rapeseed oil using PIT emulsifying system of this study can be used to apply cosmetics industry and pharmaceutical industry.