• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.58-65
• /
• 2016

This study was a preparatory experiment aimed the development of membrane scaffolds for tissue engineering. A PCL composite solution contained sodium chloride(NaCl). PCL porous membrane scaffolds were formed on a glass casting plate using a film applicator and immersed in distilled water to remove the NaCl reaching after drying. NaCl was used as a pore former for a 3 dimensional pore net-work. The dry condition parameters were $4^{\circ}C$, room temperature (RT) and $40^{\circ}C$ for each different temperatures in the drying experiment. SEM revealed the morphology of the pores in the membrane after drying and evaluated the in vitro cytotoxicity for basic bio-compatibility. The macro and micro pores existed together in the scaffold and showed a 3-dimensional pore net-working morphology at RT. The in vitro cytotoxicity test result was "grade 2" in accordance with the criterion for cytotoxicity by ISO 10993-5. The dry condition affected the formation of a 3 dimensional pore network and micro and macro pores. Therefore, these results are expected provide the basic process for the development of porous membrane scaffolds to control degradation and allow drug delivery.

• Ocean and Polar Research
• /
• v.39 no.2
• /
• pp.85-106
• /
• 2017

The Lago Sofia conglomerate in southern Chile is a deep-marine gravelly deposit, which is hundreds of meters thick and kilometers wide and extends laterally for more than 100 km, filling the foredeep trough of the Cretaceous Magallanes Basin. For understanding the depositional processes and environments of this gigantic deep-sea conglomerate, detailed analyses on sedimentary facies, architecture and paleoflow patterns were carried out, highlighting the differences between the northern (Lago Pehoe and Lago Goic areas) and southern (Lago Sofia area) parts of the study area. The conglomerate bodies in the northern part occur as relatively thin (< 100 m thick), multiple units intervened by thick mudstone-dominated sequences. They show paleoflows toward ENE and S to SW, displaying a converging drainage pattern. In the southern part, the conglomerate bodies are vertically interconnected and form a thick (> 400 m thick) conglomerate sequence with rare intervening fine-grained deposits. Paleoflows are toward SW. The north-to-south variations are also distinct in sedimentary facies. The conglomerate bodies in the southern part are mainly composed of clast-supported conglomerate with sandy matrix, which is interpreted to be deposited from highly concentrated bedload layers under turbidity currents. Those in the northern part are dominated by matrix- to clast-supported conglomerate with muddy matrix, which is interpreted as the products of composite mass flows comprising a turbidity current, a gravelly hyperconcentrated flow and a mud-rich debris flow. All these characteristics suggest that the Lago Sofia conglomerate was formed in centripetally converging submarine channels, not in centrifugally diverging channels of submarine fans. The tributaries in the north were dominated by mass flows, probably affected by channel-bank failures or basin-marginal slope instability processes. In contrast, the trunk channel in the south was mostly filled by tractive processes, which resulted in the vertical and lateral accretion of gravel bars, deposition of gravel dunes and filling of scours and channels, similar to deposits of terrestrial gravel-bed rivers. The trunk channel developed along the axis of foredeep trough and its confinement within the trough is probably responsible for the thick, interconnected channel fills. The large-scale architecture of the trunk-channel fills shows an eastward offset stacking pattern, suggesting that the channel migrated eastwards most likely due to the uplift of the Andean Cordillera.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.4
• /
• pp.529-537
• /
• 2005

Ssamjang samples were prepared by central composite design for five independent variables, Gochujang mash aging period $(X_1)$, Doenjang aging period $(X_2)$, Doenjang content $(X_3)$, sterilization temperature $(X_4)$ and storage temperature $(X_5)$. Browning characteristics of Ssamjang were analyzed such as water activity, free amino acids, free sugars and color during storage. Water activities of Ssamjang were ranged from 0.605 to 0.666 at the beginning of storage, and were shown to be the highest at the 8th week of storage and then decreased gradually. Among free amino acids the content of glutamic acid was the highest. Proline, leucine, phenylalanine, lysine and serine were slightly higher than the others. Larger amounts of free amino acids and free sugars were observed from the sample sterilized at $60^{\circ}C$ when compared to that at $70^{\circ}C$. Glucose, fructose and maltose as free sugars were identified from Ssamjang and glucose content was the largest among. During the storage, lightness $(L^*)$, redness $(a^*)$ and yellowness $(b^*)$ of Ssamjang were decreased and total color difference $({\Delta}E)$ was increased. The color changes in the sample surface were more affected by temperature of which storage temperature was more influenced than sterilization temperature.

• 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.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.3
• /
• pp.197-205
• /
• 2011

Cellulose nanofibrils (CNF) with 50~100 nm diameter were manufactured from micro-size cellulose by an application of a high-pressure homogenizer at 1,400 bar. High strength nanopapers were prepared over a filter paper by a vacuum filtration from CNF suspension. After reinforcing and dispersing CNF suspension, hydroxypropyl cellulose (HPC) and polyvinyl alcohol (PVA)-based composites were tailored by solvent- and film-casting methods, respectively. After 2, 4, 6 and 8 passes through high-pressure homogenizer, the tensile strength of the nanopapers were extremely high and increased linearly depending upon the pass number. Chemical modification of 1H, 1H, 2H, 2H-perfluorodecyl-triethoxysilane (PFDTES) on the nanopapers significantly increased the mechanical strength and water repellency. The reinforcement of 1, 3, and 5 wt% CNF to HPC and PVA resins also improved the mechanical properties of the both composites.

• Korean Journal of Food Science and Technology
• /
• v.41 no.3
• /
• pp.245-250
• /
• 2009

This study examined the optimization of alcohol extraction conditions for maximizing the total polyphenols derived from apple pomace, by response surface methodology (RSM). The effects of four independent variables, including $X_1$ (ratio of solvent to sample content), $X_2$ (dipping time), $X_3$ (extraction time), and $X_4$(extraction temperature), were investigated at five levels using central composite design (CCD). $Y_1$ (yield) and $Y_2$ (total polyphenols) were chosen as dependent variables. The coefficients of determination, $R^2$, were greater than 0.900 (0.9042 and 0.9555). The results showed that the model fit was very significant (p<0.001). The optimum extraction conditions were as follows: 13.00 mL/g for the ratio of solvent to sample content, 89.02 min for dipping time, 180 min for extraction time, and $70^{\circ}C$ for extraction temperature. At these conditions, the predicted total polyphenol content was 29.68 mg catechin equiv./g.

• Korean Journal of Food Science and Technology
• /
• v.40 no.3
• /
• pp.283-289
• /
• 2008

This study used response surface methodology (RSM) in an effort to optimize the hot water extraction conditions of dandelion leaves in order to increase antioxidant activity in the extract. A central composite design was applied to investigate the effects of independent variables, which included the ratio of solvent to sample ($X_1$), extraction temperature ($X_2$), and extraction time ($X_3$), on dependent variables of the extracts, including soluble solid ($Y_1$), total polyphenols ($Y_2$), total flavonoid ($Y_3$), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability ($Y_4$), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging ability ($Y_5$), and superoxide radical scavenging ability ($Y_6$). The estimated optimal conditions were as follows: $83.77{\pm}1.07^{\circ}C$ of the extraction temperature, $20.85{\pm}0.24 mL/g$ of solvent per sample, and $1.59{\pm}0.12$ hr of extraction time. At the optimal conditions, the predicted characteristic values were: a yield of 38.98%, a total polyphenol level of $74.28{\mu}g/mg$, a total flavonoid level of $74.00{\mu}g/mg$, a DPPH radical scavenging ability ($IC_{50}$) of 0.14 mg/mL, a ABTS radical scavenging ability ($IC_{50}$) of 3.24 mg/mL, and a superoxide radical scavenging ability ($IC_{50}$) of 2.49 mg/mL.

• Korean Journal of Food Science and Technology
• /
• v.23 no.5
• /
• pp.538-545
• /
• 1991

In order to develop low calorie noodles, flours of Jerusalem artichoke and strong wheat were mixed with ratios of 25 : 75, 30 : 70 and 35 : 65. The substitution of wheat flour with Jerusalem artichoke powder up to 25% showed good formation of noodle stripes similar to that of wheat flour alone. The formation was effectively improved by addition of $0.5{\sim}1.0%$ solution alginate, 1.0% Fremol or mixure of 0.5% ${\alpha}-Polygel$, 0.5% Alcalin and 1.5% fremol for $25{\sim}30%$ substitution with Jerusalem articoke powder. Also addition of sodium alginate to the 30% substitution with Jerusalem artichoke powder showed the high Hunter value of Lightness and good cooking quality of noodle, relatively close to those of noodle of wheat flour alone. The dough prepared with mixed flours showed increase in cohesiveness and resilience and decrease in hardness and adhesiveness, compared to those of wheat flour. The addition of sodium alginate was very effective for increase in adhesiveness and cohesiveness. The cohesiveness of cooked noodles was increased with substitution with Jerusalem artichoke powder while sodium alginate influenced little. There is no significant difference of taste, odor, color and texture of cooked noodles between wheat flour alone and composite flours with $25{\sim}30%$ of Jerusalem artichoke and texture modifying agents. The results suggested that good quality noodles could be produced using Jerusalem artichoke powder.

• Journal of the Korean Wood Science and Technology
• /
• v.28 no.4
• /
• pp.41-50
• /
• 2000

Cement-bonded particleboard is being used as outdoor siding material all over the world, because this composite particularly bears a light weight, high resistance against fire, decay, and crack by cyclic freezing and thawing, anti-shock property, and strength enhancement. Construction systems are currently changing into a frame-building style and wooden houses are being constructed with prefabrication type. Therefore, they require a more durability at outdoor-exposed sides. In this study, the cement hydration property for Korean pine particle, Japanese larch particle and face- and middle layer particles (designated as PB particle below) used in Korean particleboard-manufacturing company was investigated, and the rapid manufacturing characteristics of cement-bonded particleboard by supercritical $CO_2$ curing was evaluated. Korean pine flour showed a good hydration property, however, larch flour showed a bad one. PB particle had a better hydration property than larch flour. The addition of $Na_2SiO_3$ indicated a negative effect on hydration, however, $MgCl_2$ had a positive one. Curing by supercritical $CO_2$ fluid gave a conspicuous enhancement in the performances of cement-bonded particleboards compared to conventional curing. $MgCl_2$ 3%-added PB particle had the highest properties, and $MgCl_2$ 1%-added Korean pine particle had the second class with the conditions of cement/wood ratio of 2.7, a small fraction-screened particle and supercritical curing. On the contrary, the composition of non-hammermilled or large fraction-screened particle at cement/wood ratio of 2.2 was poorer. Also, the feasibility for actual use of 3%-added, small PB particle-screened fraction was greatest of all the conventional curing treatments. Relative superiority of supercritical curing vs. conventional curing at dimensional stability was not so apparent as in strength properties. Through the thermogravimetric analysis, it was ascertained that the peak of a component $CaCO_3$ was highest, and the two weak peaks of calcium silicate hydrate and ettringite and $Ca(OH)_2$ were present in supercritical treatment. Accordingly, it was inferred that the increased formation of carbonates in board contributes to strength enhancement.

• Journal of the Korean Wood Science and Technology
• /
• v.35 no.6
• /
• pp.100-107
• /
• 2007

People have spent lots of time inside building about 90% of these day. Industry has been developed rapidly after I960. Construction materials had changed from natural materials to chemical materials and confidentiality of building has been more higher than before by policy of saving energy. These have caused sick-building syndrome (SBS) for us. So people want environmental construction materials for their house. We designed a environmental loess (yellow soil) finishing material which was composed of loess, water, water-soluble resin, hardener and filler. The purposes of this study were that making an environmental loess finishing material with optimum ratio, evaluating the usability of loess finishing material for wall. Furthermore it was suitable for wall to evaluate mechanical properties that are impact test, cracking test, abrasion test and de-bonding test, environmental properties that were emission of VOCs, formaldehyde and far infrared radiation.