• Composites Research
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• v.29 no.6
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• pp.408-413
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• 2016

Commonly-used polymers are manufactured as versatile forms. Furthermore, continuous polymer fibers are recently manufactured using nylon or aramid fiber. One of common epoxy was also used to make polymer fibers. Bisphenol-A type was used as base epoxy whereas amine and anhydride were used as hardeners. Epoxy fibers was cured by stepping up the temperature to maintain the shape of epoxy fiber. Surface energy was measured to confirm the degree of interfacial adhesion by modified static contact angle method. After mechanical properties were measured via fiber tensile test, the evaluation of fiber fracture was proceeded. Tensile strength of epoxy fiber using amine type hardener was higher as 138 MPa than anhydride case as 70 MPa. Fractured surface exhibited different failure patterns at the cross-section.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.674-680
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• 2015

A solvent-soluble polyimide (PI) polymeric binder was synthesized by a two-step reaction for silicon (Si) anodes for lithium-ion batteries. Polyamic acid was first prepared through ring opening between two monomers, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCDA) and 4,4-oxydianiline (ODA), followed by condensation reaction. Using the synthesized PI polymeric binder (molecular weight = ~10,945), the coating slurry was then prepared and Si anode was fabricated. For the control system, Si anode based on polyvinylidene fluoride (PVDF, molecular weight = ~350,000) having the same constituent ratio was prepared. During precycling, PI polymeric binder revealed much improved discharge capacity ($2,167mAh\;g^{-1}$) compared to that of using PVDF polymeric binder ($1,740mAh\;g^{-1}$), while the Coulombic efficiency of two systems were similar. PI polymeric binder improved the cycle retention ability during cycles compared to that of using PVDF, which is attributed to an improved adhesion property inside Si anode diminishing the dimensional stress during Si volume changes. The adhesion property of each polymeric binder in Si anode was confirmed by surface and interfacial cutting analysis system (SAICAS) (Si anode based on PI polymeric binder = $0.217kN\;m^{-1}$ and Si anode based on PVDF polymeric binder = $0.185kN\;m^{-1}$).

• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.9-18
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• 2004

In this study, the observation data for the yellow sandy dust phenomena from the year 1999 to 2003 at background sites in Korea were collected at Global Atmospheric Observatory at An-Myeon island and its temporal variation were analyzed. The chemical characteristics of the fine particles were also analyzed in order to evaluate sources of the yellow sandy dust particles. The results showed that the monthly average mass concentration of the fine particles was the highest in springtime and the lowest in summertime in general. The magnitude of its variation was also the highest in March in which the occurrence of yellow sandy dust was the most frequent and thus the number of samples was the largest, while the lowest in June through September. The yearly variation of ion components contributions to the total mass concentration of the fine particles was slowly decreasing, showing that $63\%$ in 1999, $59\%$ in 2000 and $56\%$ in 2003. The most prevalent ion components in the fine particles were found to be $NO_3$ and $SO_4^{2-}$, which are known to be source materials of acidic precipitation, and $NH_4^+$, a neutralizing material of the acid precipitation. Relative proportion of metal components in the fine particles was calculated as $14\%$ in average, and their concentrations are in an order of Fe > Al > Na > Ca > Zn > Pb > Cu > Mn > Ni > Cd > Cr > Co > U. The results indicated that main sources of the metals was soil-originated Fe, Al, Ca, and Mg, and the contribution of anthropogenic air Pollution-originated Zn, Pb, Cu, Mn were also high and keep slightly increasing. Statistical analysis showed that the chemical components could be divided into soil-originated group of Mg, Al, Ca, Fe, and Mn and air pollution-originated group of $NO_3$, Zn, Pb, and they are occupying more than $60\%$of all the components in the dusty sand. The results explain that An-Myeon island is more influenced by soil-originated source than ocean-originated one and also the influencing strength of anthropogenic poilution-originated source is less than $50\%$ of that of soil-originated sources. Compared to non-yellow sandy period, the yellow sandy dust period showed that the amounts of soil-originated $Mg^{2+}$ and $Ca^{2+}$ and ocean-originated $Na^+$ and $Cl^-$ were increased to more than double and the metals of Mg, Al, Ca, Fe were also highly increased, while micro metal components such as Pb, Cd, Zn, which have a tendency of concentrating in air, were either decreased or maintained at nearly constant level. In the period of yellow sandy dust, a strong positive correlation was observed between water soluble ions and between metals in terms of its concentration, respectively. Factor analysis showed that the first group being comprised of about $43\%$ of the total inorganic components was affected by soil and they are ions of $Na^+,\;Mg^{2+}\;and\;Ca^{2+}$ and metals of Na, Fe, Mn and Ni. The result also showed that the metals of Mg and Cr were classified as second group and they were also highly affected by soil sources.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.487-498
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• 2006

Total 438 precipitation samples were collected in Jeju City between 1997 and 2005, and their major ionic components were analyzed. The comparison tests using ion balance, electric conductivity and acid fraction were performed. It was found their correlation coefficients were in the range of 0.977$\sim$0.994, indicating the good quality of collected dam. The volume-weighted mean pH and electric conductivity were 4.8 and 23.0 $\mu$S/cm, respectively. with the ionic strength of 0.23$\pm$0.20 mM. The marine ($Na^+$, $Mg^{2+}$, and $CI^-$), anthropogenic (nss$SO_4{2-}$, $NO_3^-$, and $NH_4^+$) and soil (nss-$Ca^{2+}$) species have contributed to the ionic components of precipitation samples with 43$\sim$74%, 16$\sim$37% and $\sim$5%, respectively. The seasonal variations of $NO_3^-$ and nss-$SO_4^{2-}$ showed a distinct seasonality with higher concentrations in winter than summer, indicating an increase of fossil fuel consumption and a possibility of long-range transport of those pollutants from continental area along the dominant winter westerly. The levels of nss-$Ca^{2+}$ also were appeared the highest in winter and increased comparatively in spring season. possibly due to the soil influences including the Asian Dust. The acidification contribution of nss-$SO_4^{2-}$ and $NO_3^-$ showed 88$\sim$96%, and the free acidity was in the range of 6.0$\sim$40.1%. Interestingly, the backward trajectories for the case of upper 10% nss-$SO_4^{2-}$ and $NO_3^-$ levels have passed through the China continent before their arrival to Jeju. The precipitation of pH below 4.5 has been occurred frequently when the trajectory's path lied over the China continents. On the other hand, the air masses from the North Pacific area were characterized by lower 10% of nss-$SO_4^{2-}$- and $NO_3^-$ concentration, which demonstrated that air mass from the North Pacific was the cleanest among air masses moved to Jeju.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.6
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• pp.786-791
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• 2010

The effects of fermented garlic powder on production performance, egg quality, blood profiles and fatty acid composition of egg yolk in laying hens were studied in a 35-d experiment. Two-hundred and forty (ISA brown) layers aged 41 weeks were randomly allocated into the following four treatments: i) CON (basal diet); ii) G1 (CON+fermented garlic powder 1.0%); iii) G2 (CON+fermented garlic powder 2.0%) and iv) G3 (CON+fermented garlic powder 3.0%). There were no differences (p>0.05) among treatments in egg production, egg weight, eggshell breaking strength and eggshell thickness throughout the whole experimental period. However, yolk height was increased significantly (p<0.05) by the addition of fermented garlic powder during the 5th week while yolk color was greater (p<0.05) in G2 and G3 than in CON and G1 in the 5th week. Compared with CON, Haugh unit was increased (p<0.05) in response to fermented garlic powder treatments during the 5th week. No significant effects on total protein, albumin and IgG were observed in response to any of the treatments over the experimental period (p>0.05). There was a significant (p<0.05) reduction in plasma cholesterol concentration when the dietary level of fermented garlic powder was increased from 0.0 to 3.0%. The levels of saturated fatty acids (SFA) were significantly decreased (p<0.05) in response to G2 and G3 while monounsaturated fatty acids (MUFA) were higher (p<0.05) in G2 and G3 treatment groups than in CON and G1. Compared with other treatments, polyunsaturated fatty acids (PUFA) and PUFA:SFA ratio were higher (p<0.05) in G3. In conclusion, this study demonstrated that addition of fermented garlic powder reduced plasma cholesterol concentration and did not cause adverse effects on production performance. Moreover, addition of 3.0% garlic powder decreased SFA but increased PUFA and PUFA:SFA ratio in egg yolk.

• Journal of Society of Preventive Korean Medicine
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• v.21 no.2
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• pp.117-126
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• 2017

Objectives : The use of health functional foods is gradually increasing. On the other hand, the use of the Korean herbal medicine is gradually decreasing. Especially children are known to have a high percentage of taking a health functional food. This study was designed to compare the use of health functional food with the reason for taking the Korean herbal medicine. Methods : The participants were 453 parents who have kids age between 3 to 6 years old from day care center in Wonju and Chungju. The questionnaire consisted of 17 questions and the survey was conducted by self-entry method. This study analyzed 374 participants' questionnaires who agreed to the survey. Results : The percentages of children's health functional food intake experience were 82.9% and they usually bought products which contain lactic acid bacteria(55.6%). The reason for consuming health functional food was to strengthen the immune system and enhance the physical strength. Most of the participants purchased health functional food from pharmacy through inaccurate information such as the internet. The percentages of children's health functional food preference were 58.5% because it is easy to take. The percentages of children's herbal medicine preference were 41.7%. There are inconveniences of taking herbal medicine because of taste and smell(68.8%). Conclusions : Therefore, it is necessary to change the formulation of the herbal medicine and increase convenience for use of the herbal medicine to preschooler(3-6 years old). In additionary, it is necessary to supply accurate and up to date information of herbal medicine taking.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.175-180
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• 1998

As a part of investigation for quality improvement of surimi gel from fish with a red muscle by addition of calcium-based powder from fish bone, we investigated the processing condition of calcium-fortified mackerel surumi gel and its quality stability during storage at $5^{\circ}C$. Judging from the results of the soluble calcium content and jelly strength, the reasonable addition concentration of calcium-based powder from Alaska pollack bone for improvement of functional properties in surimi gel was revealed 0.9% on the weight basis of the chopped mackerel meat. The soluble calcium content of the calcium-fortified surimi gel (105.0 mg/100 g) was more than that of the ordinary surumi gel (2.9 mg/100 g). During cold storage of calcium-fortified surumi gel, the moisture contents, amino acid compositions, soluble calcium and phosphorus contents were little changed, the pH, volatile basic nitrogen contents, histamine contents, peroxide values and brown pigment formation were slightly increased and viable cell counts and coliform groups were not detected. The calcium-fortified surimi gel was superior in the lysine and calcium contents, EPA and DHA compositions to the ordinary surumi gel. Judging from the results, it was suggested that calcium-fortified surumi gel was nutritive, functional and safety foods.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.466-472
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• 2013

This study was performed to determine the effects of the pretreatment and cold-vacuum drying methods on the physicochemical properties and antioxidant activities of dried peaches. Moisture content was significantly lower with 0.3% NaCl treatment with cold-vacuum drying. The pH, brix and acid ratio (SS/TA) were the lowest with 1.0% soluble Ca treatment, while soluble solid and SS/TA were significantly higher with 0.1% vitamin C treatment compared to those with other treatments. The ${\delta}E$ and browning degree was lower in the pretreated sample compared to the untreated sample. Cutting strength of dried peaches was highest in the pretreated samples, and it was the highest with 1.0% soluble Ca treatment. Total sugar content with 0.1% vitamin C and 1.0% soluble Ca treatment was significantly higher than that with 0.3% NaCl treatment. The free sugar content was lower with 0.3% NaCl treatment but it was higher with 0.1% vitamin C and 1.0% soluble Ca treatment. The sensory evaluation result was highest with 0.1% vitamin C treatment. Phenolic compounds and antioxidant ability were the highest with the 0.1% vitamin C and 0.1% soluble Ca treatment; all the dried peaches showed relatively high antioxidant activities. These results suggest that pretreatment can affect the quality of dried peaches, showing that cold-vacuum drying can be applied for the production of high quality dried peach products.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.373-378
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• 1991

The skin and fleshy substance on the net fiber of sponge-gourd fruit pressed mechanically was removed with 0.2% NaOH solution in $3{\sim}5$ hours. The treatment of 0.2% NaOH with 0.02% Monopol(non-ionogenic polyoxethylen derivative) as surfactnat and with 0.1% $Ca(OCl)_2$ as bleaching agent enhanced the effect to remove the fleshy substance and improve the quality of net fiber. Also, the wet hardness and tensile strength of net fiber were controlled by the crosslinkage of the fiber with glu tardialdehyde, glyoxal, and formalin, respectively. The net fiber was stable on the acid and alkaline solutions. Also the range of temperature to degradate the fiber was $338{\sim}385^{\circ}C$. These values indicated a fair stability. The improved net fiber can be used for raw material of bath, dish washing, oil and gas filter, and many kinds of decorations.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.502-506
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• 2017

To improve the storage and firmness of Tteokbokki tteok Korean-style rice cakes with spicy sauce, steaming of the rice dough, soaking of the rice cake in acidic solution, and heat sterilization were conducted sequentially. The untreated control could be stored for 1 month under cold conditions, but this was extended to 10 months at room temperature ($15-30^{\circ}C$) after immersion in lactic acid solution (pH 4.0) for 20 min and heating to $100^{\circ}C$ for 30 min. The mechanical strength, which was related to firmness, was significantly increased to $11.4kgm/s^2$ compared with the untreated rice cakes ($8.8kgm/s^2$, p<0.05) and the overall descriptions of the sensory evaluation, including texture, was significantly higher than the control (p<0.05). The average size of the pores in the treated rice cakes was smaller than that of the conventional sample and the texture was improved as a result of decreased starch elution from smaller pores.