• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.646-650
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• 2001

In this study, we investigated the thermotropic behavior of Daucus carota L. (DCS) extracts in phosphatidylcholine(PC) liposomes using high-sensitivity differential scanning calorimetry (nano-DSC). We used dipalmitoylphosphatidylcholine (DPPC) bilayers which made most stable liposomes among the other phosphatidylcholine. The sample DCS was extracted and fractionated to four different types, hexane(DCSMH), ethylacetate (DCSMEA), butanol (DCSMB) and aqueous(DCSMA) fractions. Compared to the other fractions of Daucus carota L., the DCSMH and DCSMEA fractions markedly affected the thermotropic properties of DPPC liposomes, broadened and shifted the thermograms of transition to lower temperatures. The incorporation of DCSMH and DCSMEA in DPPC liposomes were preferentially located in the hydrophobic core of DPPC bilayers, where it reduced the lipid packing orderness (cooperative unit) in the gel state compared to it in the liquid-crystalline state. These results suggest that the activities of the Daucus carota L. extracts to enhance the fluidity of the liposomal membrane have implication in their biological activities.

• Elastomers and Composites
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• v.21 no.1
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• pp.13-19
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• 1986

The effects of several vulcanizing accelerators on the determination of kinetic parameters of natural rubber vulcanizate was studied by DSC. Kinetic parameters were determined by means of the calculation procedures of Borchardt-Daniels and Oscillating Disk Rheometer (ODR) cure curve analysis, using both DSC exothermal thermogram and ODR cure curve. In order to examine the credibility in the DSC method the same compound which was und for DSC method was used for the comparison with the results of ODR data. Upon this method, kinetic rate constant (k), and Arrehenius parameter (Ea, ko, n) have been determined for rubber compounds via a new method using DSC thermogram and ODR cure curve. In the comparison of DSC and ODR results, kinetic parameters has shown good agreements between two results. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method of kinetic study of rubber vulcanization.

• Polymer(Korea)
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• v.38 no.3
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• pp.320-326
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• 2014

The effects of high shear rate processing on the thermal properties of PC/ABS blends were studied. It was executed by the high shear processing machine (NHSS2-28) at the varied conditions of screw speeds and loaded duration. After the samples were processed with NHSS2-28, the $T_gs$ were shifted from 143 to $133^{\circ}C$, and the behavior of degradation determined by TGA showed two distinct steps before high shear rate processing, while it showed a straight line after the processing. In order to provide the reasons of the properties, it was showen by SEM and UTM that the droplet sizes morphologically decreased after the processing, and the elongations decreased slightly until 1000 rpm of screw speed and then sharply decreased, according to the conditions of high shear rate processing. Therefore, it can be confirmed that $T_g,s$ of PC/ABS blends were considerably shifted under an appropriate high shear rate condition, and rapidly dropped, so that blends degraded above the condition, due to stress-induced degradation.

• Food Science and Preservation
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• v.12 no.2
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• pp.101-106
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• 2005

This study was carried rut to investigate the quality properties of two cocked germinated-brown rices(A- and B-product). Color value of A- and B-product were L=68.46, a=0.92, b=9.49 and L=69.32, a=-1.10, b=9.77, respectively. Moisture content of those was $64.5\%$. The free sugar contents of A-product were $0.2\%$ glucose, $0.15\%$ sucrose, $0.18\%$ maltose, and those of B-product were $0.14\%$ glurose, $0.50\%$ sucrose, $0.17\%$ maltose, respectively. Vitamin E content in A-product was $30.7\;{\mu}g\;100\;g$ and $46.9\;{\mu}g\;100\;g$ in B-product. Total dietary fiber contents were $2.8\%$, and $2.2\%$, respectively. The DSC(differential scanning calorimetry) characteristics of two cooked germinated-brown rices showed similar pattern. Onset temperature and gelatinization enthalpy of peak 1 were $56.5^{\circ}C$, 5.46 J/g in A-product and $56.2^{\circ}C$, 5.56 J/g in B-product, respectively. Onset temperature and melting enthalpy of peak 2 were $109.5^{\circ}C$, 0.33 J/g in A-product and $108.9^{\circ}C$, 0.37 J/g in B-product, respective1y. Sensory properties of cocked germinated-brown rices were affected by appearance, taste and texture. Palatability score of B-product was higher than that of A-product.

• Composites Research
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• v.28 no.6
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• pp.395-401
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• 2015

This study investigated the thermal stability of Grubbs' catalyst and its reactivity with self-healing agents for self-healing damage repair. Four types of Grubbs' catalyst supplied by manufacturers were considered and each catalyst was tested in as-received and grinded conditions. Four types of self-healing agents were prepared by varying the mixing ratio of dicyclopentadiene (DCPD) and 5-ethylidene-2-norbonene (ENB). Heat flows as a function of temperature were measured through a differential scanning calorimetry (DSC) to determine the thermal stability of catalysts. Reaction heats of self-healing agents with the catalyst were measured to evaluate the reactivity of the catalyst. For this evaluation, Fluka Chemika Grubbs' catalyst was used based on the maximum temperature and the time to reach the maximum temperature. According to the results, catalysts had different shapes depending on the manufacturer and the results showed that the smaller the size of the catalyst the higher the reactivity with self-healing agents. As the ENB ratio in self-healing agents increased, the maximum temperature increased, and the time to reach the maximum temperature decreased. As the amount of the catalyst increased, the maximum temperature increased, and the time to reach the maximum temperature decreased. Considering the thermal stability of the catalyst and its reactivity with the self-healing agent, combination of 0.5 wt% catalyst and the D3E1 self-healing agent was optimal for self-healing damage repair. Finally, as the thermal decomposition may occur depending on the environmental temperature, the catalyst must not be exposed to temperature higher than that is necessary to maintain the thermal stability of the catalyst.

• Composites Research
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• v.33 no.3
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• pp.161-168
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• 2020

In this paper, we have studied the mechanical properties of thermoplastic carbon fiber fabric composites with spread technology and compression molding temperature were investigated. Carbon fiber reinforcement composites were fabricated using commercial carbon fiber fabrics and spread carbon fiber fabrics. Mechanical properties of the commercial carbon fiber composites (CCFC) and spread carbon fiber composites (SCFC) according to compression molding temperatures were investigated. Thermal properties of the polypropylene film were examined by rheometer, differential scanning calorimetry, thermal gravimetric analysis. Tensile, flexural and Inter-laminar shear test. Commercial carbon fiber reinforcement composites and spread carbon fiber composites were fabricated at 200~240℃ above the melting temperature of the polypropylene film. Impregnation properties according to compression molding temperature of the polypropylene film were investigated by scanning electron microscopy. As a result, as the compression molding temperature was increased, the viscosity of the polypropylene film was decreased. The mechanical properties of the compression molding temperature of 230℃ spread carbon fiber composite was superior.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.294-301
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• 2020

This study evaluated the burnability and hydration reaction of clinker burned with high Al₂O₃ content OPC to apply large amounts of industrial by-products in the cement manufacturing process. Specifically, after preparing a clinker with a high C₃A content by burning the OPC raw material with a high content of Al₂O₃ in a laboratory electric furnace, the burnability of the clinker was evaluated through XRD Rietveld analysis and polarization microscopy, and clinker hydration reactivity was reviewed through the Isothermal conduction calorimetry analysis and the cement compressive strength. As a result, the kiln burning temperature for the production of high Al₂O₃ content clinker lower, and the compressive strength was equal to or higher than OPC. Therefore it was confirmed the possibility to manufacturing energy-saving high Al₂O₃ content clinker using a large amount of industrial by-products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1559-1563
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• 2009

Scaled-up production of oil containing diacylglycerol (DAG), so called diacylglycerol-oil, was produced by lipase-catalyzed reaction. Mixture of soybean oil and glyceryl monooleate with 1:2 molar ratio was esterified with Lipozyme RMIM in a batch-type reactor at 55$^{\circ}C$ and 300 rpm during 6 hr. After short-path distillation for removal of monoacylglycerol and free fatty acid as reaction by-products, diacylglycerol-oil mainly consisted of DAG (29 area%) and TAG (71 area%). The major compositional fatty acids in diacylglycerol-oil were oleic (44.36 wt%), and linoleic acids (37.36 wt%). Acid value and iodine value of diacylglycerol-oil were 0.13 and 112.6, respectively. Solid fat content (SFC) of diacylglycerol-oil was observed after differential scanning calorimetry (DSC) analysis in which three melting peaks at -25.0, 0.1, and 11.2$^{\circ}C$ were shown.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.616-621
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• 2017

The objective of this study was to investigate the physicochemical properties of domestic strong wheat flour (DSWF). Three commercial DSWFs (D1, D2, and D3) were compared with imported strong wheat flour (ISWF). DSWFs had higher moisture content, crude protein content, lightness, and whiteness than ISWF. DSWFs showed lower solvent retention capacity and water absorption index than ISWF. DSWFs also showed significantly higher water solubility index than ISWF (P<0.05). Setback values by rapid visco analysis were significantly higher in D1 and D2 than in ISWF and D3, which means ISWF and D3 were better in retarding retrogradation. Differential scanning calorimetry results showed that ISWF required 6.2 J/g of energy for phase transition, whereas DSWFs needed 6.67~7.13 J/g. The farinograph results showed that ISWF had higher water absorption, longer dough stability time, and significantly higher softening of dough at 20 min than DSWF (P<0.05). Dough resistance and extensibility were higher in ISWF than in DSWFs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.1-8
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• 1992

A 4-week energy balance study was conducted to estimate the energy expenditure (EE) of 7 high school age men, 16 to 18 year of age, by measurement of energy intakes and changes in body energy (BE) content (intake/balance technique), keeping their normal living pattern and maintenance body weight. Gross energy intake (GE) and fecal energy (FE) loss was measured by bomb calorimetry, Urinary energy (UE) loss was calculated from nitrogen excreted. Fat mass (FM) was determined from body density estimated from skinfold thickness. 1) Mean constitutional ratio of carbohydrate, protein and Int for the total energy intake was $73.7{\pm}0.3%$, $13.5{\pm}0.3%$ and $12.9{\pm}0.5%$, respectively. 2) Fecal energy loss was 2.4% proportion of the gross energy intake. 3) Mean daily metabolizable energy estimated by subtract fecal and urinary energy loss was $2582{\pm}61\;kcal$. 4) Total body energy change estimated from body composition change over 28 days was decreased $4309{\pm}1837kcal$. 5) Mean daily energy expenditure was $2736{\pm}59kcal\;(46{\pm}1kcal/kg$ of body weight).