• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.57-62
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• 2000

Sulfonated Polysulfone (SPSF) cation-exchange membranes were synthesized by introducing various ratio of chlorosulfuric acid (CSA) onto the main chain of polysulfone (PSF). Properties such as ion exchange capacity, water content, liked ion concentration, and partition coefficient were measured, respectively. Through the analysis of DSC and TGA, it has been shown that glass transition temperature increased and weight loss decreased as sulfuric acid group concentration increased. Structure of membrane measured by AFM and SEM was seen to be asymmetric. Apparent diffusion coefficient of sodium ions through SPSF membrane by AC impedance was increased as sulfuric acid group concentration increased.

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.120-127
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• 2004

This study was conducted to evaluate quality characteristics of noodles when different concentrations of chlorella extract powder were added to the wheat flour. The characteristics of noodle including cooking properties, color, mechanical texture properties, and sensory properties were determined. The noodles containing chlorella extract powder exhibited higher values in cooked weight, volume, moisture absorption, and cooking loss. When the amount of chlorella extract powder increased, the Hunter L(lightness) value, a(redness) value of cooked noodles decreased but b(yellowness) value increased. From the textural properties measured by texture analyzer, the noodles with chlorella extract powder were significantly lower in hardness, cohesiveness, springiness, gumminess, and chewiness than those of 100％ wheat noodle. The results of sensory evaluation of cooked noodles containing chlorella extract powder indicated that the cooked noodle with 1.5％ chlorella extract powder showed the highest value. Based on cooking properties and sensory evaluation, chlorella extract powder up to 1.5％ could be substituted for wheat flour to improve the noodle quality.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.371-377
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• 1998

The effect of epoxy resin on the water stability of HAC/PVA based MDF cement composite were stu-died through the three different forming methods calendering extruding and warm pressing. In prexing step the epoxy resin was added in 5-15wt% of cement weight. The 3-point flexural strength of each dry and wet specimen which were immersed in water during 3. 7, 14 days was estmated and the mi-crostructural change of epoxy resin-added MDF cement composite due to water immersion was charac-terized by scanning electron microscopy. As the addition amount of epoxy resin the im-provement of water stability of MDF cement composite was achieved in most case. Especially through the warm press forming method the effectiveness of epoxy resin addition to the water stability was enhanced. When the epoxy resin was added by 5wt% to 7wt% the optimum flexural strength and water stability

• Polymer(Korea)
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• v.33 no.5
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• pp.477-484
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• 2009

Suspension polymerization with hydrophobic silica as a stabilizer and AIBN as an initiator was conducted to synthesize PBMA particles and PBMA composite particles containing carbon black. Surface modification of silica particles by controlling pH revealed that 90% of them functioned as stabilizer and 10% were incorporated into PBMA particles. While stabilizer concentration had no impact on reaction kinetics and particle diameter, an increase in stabilizer concentration displayed an increase in molecular weights when it exceeded 1.67 wt%. An increase in initiator concentration and reaction temperature decreased molecular weights in close agreement with the theoretical equation. An increase in carbon black concentration from 1 to 7 wt%, relative to the monomer, showed a progressive decrease in reaction conversion. As carbon black was increased from 3 to 5 wt%, glass transition showed a $4^{\circ}C$ increase. The presence of carbon black was confirmed by TEM while its concentration was measured by TGA.

• Fire Science and Engineering
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• v.10 no.3
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• pp.3-9
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• 1996

The Polyimide thin films based on PMDA and 4,$4^{\circ}$'-DDE were fabricated by VDPM, and their heat resistance characteristics were invastigated by TGA(Thermogravimetry Analyzer). It was found that deposition rate decreased with increasing substrate temperature and the thin films were not fabricated over the substrate temperature of $70^{\circ}$. $T_{TG}$ of weight loss temperature is $565^{\circ}$, $397^{\circ}$ and $210^{\circ}$ at the substrate temperature of $20^{\circ}$, $40^{\circ}$ and $70^{\circ}$, respectively. It is realized that the endurace temperature for 20,000 hour of thin films fabricated at $20^{\circ}$ and $40^{\circ}$ is $230^{\circ}$ and $200^{\circ}$, respectively.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.405-409
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• 2003

This study was conducted to evaluate quality characteristics of noodles containing barley flour and ${\beta}$-glucan enriched fraction. Compared to 100% wheat flour, composite flours containing barley flour and ${\beta}$-glucan enriched fraction decreased initial pasting temperature and increased maximum peak viscosity. The noodles containing ${\beta}$-glucan enriched fraction exhibited somewhat darker color and lower values in cooked weight, volume, moisture content, and cooking loss. From the textural properties measured by texture analyzer, the noodles with 30% barley flour and ${\beta}$-glucan enriched fraction were similar to 100% wheat noodle in springiness value and significantly higher in gumminess, hardness, and chewiness. The results of sensory evaluation indicated that barley flour or ${\beta}$-glucan enriched fraction at levels up to 30% could be substituted for wheat flour without seriously depressing noodle quality. Cooking of raw noodle with ${\beta}$-glucan enrichment slightly increased total, insoluble, and soluble ${\beta}$-glucan content.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.59-63
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• 1999

To verify allelopathic effects, seed germination and seedling growth test, chemical analysis and bioassay of selected species were carried out with naturally occurring chemicals of Artemisia capillaris. Seed germination ratio of Calamagrostis arundinacea. Youngia denticulata and Lactuca indica var. laciniata showed decrease in proportion to increase in aqueous extracts concentration of A. capillaris. while that of Cosmos bipinnatus and Leonurus sibiricus did not. However, dry weight growth of selected species treated with the same extracts as the above experiment was inhibited remarkably compared to the germination test. In the test at different concentrations of essential oil from A. capillaris, seedling growth of A. princeps var. orientalis and Plantago asiatica was suppressed according to the concentration of the essential oil, and root growth of the selected species was more inhibitory than that of shoot growth. Thirty-six chemical compounds were identified from A. capillaris plant by gas chromatography. Seven compounds out of 36 were bioassayed, and terpinen-4-ol was the most toxic among the tested substances.

• Food Science and Preservation
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• v.10 no.2
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• pp.131-135
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• 2003

Bell pepper was packed with several plastic films, and investigated the quality Characteristics such as gas composition, weight loss, microbial load, soluble solid content, ascorbic acid and color during storage at 10$^{\circ}C$. Cast polypropylene (CPP), low density Polyethylene (LDPE), Polyolefin (MPD, PD961) and linear low density polyethylene (LLDPE) were used for this purpose. Oxygen concentration inside packages generally showed a 10∼14% after 1∼2 weeks, but package with CPP maintained above 15％ throughout the storage. Carbon dioxide concentration of CPP was above 2%, but other treatments showed below 2%. Weight loss of all treatments was below 3.0% after 5 weeks. Total microbial count showed a similar pattern compared to yeast and mold, and CPP maintained the highest microbial load after 3 weeks. Yellowness (b value) of bell pepper was generally increased throughout the storage, and MPD and PD961 were higher than other treatments.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.182-184
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• 1984

In order to develop the storage method of pine agaric by irradiation, pine agarics irradiated with 1,2 and 2.5 kGy were stored in natural low temperature storage room ($15{\pm}2^{\circ}C$, RH: $80{\pm}5%$) and the physicochemical properties were investigated during the 15 days of storage. Veil opening rate of pine agaric was 97% after 7 days storage in control, whereas only 5% in 2-2.5 kGy irradiated groups. Rotting rate after 7 days storage were 28% in control,5-8% in 2-2.5 kGy irradiated groups. In comparison of weight loss, texture and appearance.2-2.5 kGy irradiated groups were better than control. Chemical composition of pine agaric was not remarkably changed by the irradiation and storage period except a slight increase in reducing sugar and a decrease in ascorbic acid by the increase of irradiation dose.

• Food Science and Preservation
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• v.6 no.2
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• pp.137-142
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• 1999

Physicochemical properties were evaluated for stored garlic bulbs during 9 months under different conditions, such as low-temperature condition (3${\pm}$1$^{\circ}C$, 80${\pm}$5% RH, LT), pit-temperature condition (9${\pm}$6$^{\circ}C$, 80${\pm}$5% RH,PT) and ambient-temperature condition (14${\pm}$11$^{\circ}C$, 67${\pm}$5% RH, AT). The internal sprout development was more significant in pit and ambient conditions than in low temperature and thus certain means for sprout control is required for long-term storage of garlic bulbs under such conditions. The rates of rotting and weight loss were appreciable especially after 7 months of storage (next March) in the order of PT, AT and LT, when external sprouts were observed in PT and AT. Moisture content of stored samples were relatively constant in LT until next May, but that in W and AT was significantly reduced after next January. Total sugars showed a decreasing tendency with the prolonged period, whereas an apparent increase was found in the contents of reducing sugar and vitamin C along with external sprouting of garlic bulbs from the 7th month of storage (next March). Based on the results that around March is a limiting point in garlic storage at such conditions from the physiological and physicochemical points of view, improved storage condition should be applied to overcome the storage barrier.