• Membrane Journal
• /
• v.8 no.1
• /
• pp.29-41
• /
• 1998

Thin-film composite reverse osmosis membranes of aromatic polyamides were prepared by the interfacial polymerization. Aromatic polyamides as active skin layer were made from the interfacial polymerization of MPD(m-phenylene diamine) in the aqueous and TMC(trimesoyl chloride) in HCFC(1,1-dichloro-1-fluoroethane) organic solvent. The performances of the various reverse osmosis composite membranes prepared by changing processing variables were examined. The performance of membrane manufactured by batch system was varied with organic solvent, monomer concentration, dipping time, heat treatment temperature, acid acceptor, ethanol post treatment, and acid post treatment. Ethanol post treatment was the most dominant factors in increasing permeate amount, while the monomer concentration and dipping time were the main factors in increasing selectivity. The spiral-wound module was produced with the membrane prepared at optimum condition of the continuous process. Comparing the performance of this membrane module made here with that of commercial membrane module, the permeate flux was increased by 33% while the rejection was decreased by 5%.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.28 no.2
• /
• pp.91-97
• /
• 2018

Indium hydroxide powder was prepared by precipitation method. The reaction temperature ($150{\sim}250^{\circ}C$) and the holding time at each reaction temperature (1~72 h) were used as experimental variables. The particle size, microstructure and crystal phase of each prepared powder were observed through X-ray diffraction (XRD), Transmission electron microscope (FE-TEM) and BET. In this study, we investigated the phase and microstructural change induced by heat treatment of indium hydroxide nanoparticles at various temperatures for different holding times.

• Polymer(Korea)
• /
• v.24 no.3
• /
• pp.342-349
• /
• 2000

Hollow fiber membranes were prepared via thermally-induced phase separation process followed by stretching process from isotactic polypropylene and soybean oil system. Various operating parameters were examined in terms of their effects on the structure variation and performances of the membrane, and were optimized. Melt viscosity of the melt sample had influence on the formation of the microfibrils, and addition of nucleating agent increased the nucleation density to enhance the interspherulitic pore formation by stretching. Annealing the membrane at its stretched state relaxed the stress induced by stretching and helped the membrane maintain the stretched structure without shrinking. Solid-liquid Phase separation is more prevalent when the nucleating agent was added, and coagulation bath temperature determined the nucleation density, which affected the pore formation by stretching. In the absence of nucleating agent, nucleation was not effective and liquid-liquid phase separation governed the structure formation, which showed the opposite trend to that of the case with nucleating agent.

• Applied Chemistry for Engineering
• /
• v.30 no.3
• /
• pp.331-336
• /
• 2019

In this study, required properties and optimized procedure conditions for the pitch based soft carbon anode of lithium ion battery was investigated for improving the initial efficiency and rate performance. Each petroleum residue was thermally treated at 360, 370, and $410^{\circ}C$ for 3 hours to synthesis a pitch and the corresponding pitch shows the softening point of 86, 98, and $152^{\circ}C$, respectively. The elemental analysis and thermal characteristics of the pitch were investigated by EA analysis and TGA. It was noted that the low H/C and improved thermal stability were obtained with the high softening point. The obtained pitch was carbonized at $1,200^{\circ}C$ for 1 hour to produce a soft carbon based anode. As a result of investigating the crystal structure by XRD analysis, it was found that the crystallinity of soft carbon increased with increasing the softening point. It was considered that relatively higher boiling components and decreases in the evaporation component resulted the components participation for cyclization during the heat treatment process. The soft carbon based anode with an improved crystallinity shows the enhanced initial efficiency and rate performance. The mechanism of both improvements was also discusssed based on the developed crystal structure of soft carbon based anode materials.

• Korean Journal of Food Science and Technology
• /
• v.38 no.3
• /
• pp.355-360
• /
• 2006

Antioxidative activity and physicochemical characteristics of heat-treated licorice extracted by ethyl-acetate (EtOAc) and ethyl-alcohol (EtOH) were evaluated at various treatment temperatures (110, 120, 130, 140, and $150^{\circ}C$), times (1, 2, 3, 4, and 5 hr), and moisture contents (10, 20, 30, 40, and 50%). Maximum extraction yields of EtOAc treated at $140^{\circ}C$, 2 hr, and 20% moisture content and EtOH extracts treated at $120^{\circ}C$, 2 hr, and 40% moisture content were 9.48 and 32.90%, whereas those of control were 3.74 and 14.60%, respectively. Highest total polyphenol content was obtained from 13.95 mg/g EtOH extract treated at $150^{\circ}C$, 3 hr, and 30% moisture content (control: 6.92 mg/g). Highest antioxidative activity $(IC_{50})$ was obtained from 0.32 g/L EtOAc treated at $140^{\circ}C$, 2 hr, and 20% moisture content (control: 0.57 g/L). Highest ascorbic acid equivalent antioxidant activity value of 2,112.61 mg ascorbic acid (AA) eq was obtained from EtOAc extract treated at $120^{\circ}C$, 2 hr, and 40% moisture content (control: 1,920.27 mg AA eq). Optimum heat treatment conditions were $130-140^{\circ}C$, 3 hr, and 30% moisture content.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.6
• /
• pp.689-695
• /
• 2007

Antioxidative activity and polyphenol contents of heated licorice in Korea extracted by ethyl.acetate (EtOAc) and ethyl.alcohol (EtOH) were evaluated at various heating temperatures (110, 120, 130, 140, and $150^{\circ}C$), times (1, 2, 3, 4, and 5 hr), and moisture contents (10, 20, 30, 40, and 50%). Maximum extraction yields of EtOAc extract was 10.9% at $130^{\circ}C$, 3 hr, and 50% moisture content and that of EtOH extract was 25.0% at $120^{\circ}C$, 2 hr, and 20% moisture content, whereas those of control were 0.8 and 15.8%, respectively. The highest total polyphenol content was 845.67 mg/100 g in EtOH extract at $120^{\circ}C$, 2 hr, and 20% moisture content (control: 277.00 mg/100 g). The antioxidative activity ($IC_{50}$) was the highest value of 0.53 mg/mL in EtOAc extract at $120^{\circ}C$, 2 hr, and 20% moisture content (control: 12.34 mg/mL). The highest ascorbic acid equivalent antioxidant activity value of 1,584 mg ascorbic acid (AA) eq was obtained from EtOAc extract at $120^{\circ}C$, 2hr, and 40% moisture content (control: 1,263 mg AA eq). Optimum heating conditions for the improvement of antioxidative activity of licorice in Korea was $120^{\circ}C$, 2 hr, and $20{\sim}40%$ moisture content.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.21 no.4
• /
• pp.158-163
• /
• 2011

$CuInS_2$ thin films were prepared using a sol-gel spin-coating method. That makes large scale substrate coating, simple equipment, easy composition control available. The structural and optical properties of $CuInS_2$ thin films that include less toxic materials (S) instead of Se, tetragonal chalcopyrite structure. Copper acetate monohydrate ($Cu(CH_3COO)_2{\cdot}H2O$) and indium acetate ($In(CH_3COO)_3$) were dissolved into 2-propanol and l-propanol, respectively. The two solutions were mixed into a starting solution. The solution was dropped onto glass substrate, rotated at 3000 rpm, and dried at $300^{\circ}C$ for Cu-In as-grown films. The as-grown films were sulfurized inside a graphite container box and chalcopyrite phase of $CuInS_2$ was observed. To determine the optical properties measured optical transmittance of visible light region (380~770 nm) were less than 30 % in the overall. The XRD pattern shows that main peak was observed at Cu/In ratio 1.0 and its orientation was (112). As annealing temperature increases, the intensity of (112) plane increases. The unit cell constant are a = 5.5032 and c = 11.1064 $\AA$, and this was well matched with JCPDS card. The optical transmittance of visible region was below than 30 %.

• Journal of the Korean Ceramic Society
• /
• v.39 no.8
• /
• pp.721-727
• /
• 2002

In order to overcome trade-off among compositions, process and properties of the glasses with high PbO-base composition for PDP Rib, we studied glass crystallization and crystallization kinetics by Differential Thermal Analysis(DTA). Glass powder was obtained through melting/cooling/grinding, with 3 wt%TiO2 addition for the crystal nucleation and growth in $62PbO-19B_2O_3-10SiO_2-9(Al_2O_3-K_2O-BaO-ZnO)$(in wt%) composition glass. This powder was heat-treated for 1 to 10 h at $445^{\circ}C$ for nucleation. DTA measurements were performed to obtain the crystallization peak with $5∼25^{\circ}C/min$ heating rates. DTA crystallization peak temperature increased with increasing the heating rate and decreased with increasing the heating time. Because the Avrami parameter (n) was approximately 1, the surface crystallization occurred. The maximum nucleation time was 2 h.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.5
• /
• pp.905-910
• /
• 2004

This study was carried out to observe the change of oriental melon juice quality during manufacture by heating condition and enzyme treatment. To use over-production oriental melon effectively, oriental melon juice was prepared with change of heating temperature and heating time. The heating conditions for minimum filtration time were 98.57$^{\circ}C$ and 11.29 min. The optimum conditions Predicted for separation ratio of clear solution, filtration time and browning color intensity of oriental melon juice were 98$^{\circ}C$, 13 min. In the pectin-degrading enzyme treatment test, turbidity showed minimum value in 4.40 mg％(pectin-degrading enzyme content)， 39.72 mg％ (gelatin content) and 24.09 min (treatment time)．Browning color intensity showed minimum value in 9.33 mg％ (pectin-degrading enzyme content)，44.70 mg％ (gelatin content) and 115.56 min (treatment time). The optimum conditions predicted for turbidity and browning color intensity of oriental melon concentration Juice were 6.6 mg％ (pectin-degrading enzyme content), 33.6 mg％ (gelatin content) and 70 min (treatment time).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.4
• /
• pp.549-556
• /
• 2005

Response surface methodology (RSM) was applied in steaming and roasting processes of Polygonatum odoratum roots in order to monitor hypoglycemic components and sensory property. In steaming and roasting processes based on the central composite design with variations in steaming time $(60\~180\;min)$, roasting temperature $(110\~150^{\circ}C)$ and roasting time $(10\~50\;min)$, coefficients of determinations $(R^2)$ were 0.8691 (p<0.05), 0.8253 (p<0.l0), 0.8727 (p<0.05), 0.8706 (p<0.05) and 0.8316 (p<0.10) in soluble solid, stigmasterol, $\beta-sitosterol$, hypoglycemic component (total), and overall acceptability, respectively. The maximum value of soluble solid was $71.47\%$ in 65.24 min of steaming time, $126.93^{\circ}C$ of roasting temperature and 37.58 min of roasting time. The maximum value of hypoglycemic component (total) was $764.10\;{\mu}g/g$ in 107.76 min, $117.78^{\circ}C$ and 14.70 min. Meantime, the maximum value of overall acceptability was 6.89 in 126.04 min, $115.79^{\circ}C$ and 43.93 min. The predicted values in optimum conditions for hypoglycemic components and sensory property were in good agreement with experimental values.