• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1350-1356
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• 1998

An attempt was made to investigate the effects of additives (3%) such as egg white, soybean protein, corn starch and Read Amity-N (green bean starch 85%+psyllium husk 10%) on the thermal properties and gel structures of mackerel surimi and to examine the quality of surimi by using differential scanning calorimetry (DSC), rheometry and scanning electron microscopy (SEM). The thermal transition temperatures of mackerel surimi protein were 40, 52, 67 and $79^{\circ}C$ after those temperatures were changed to 37, 46, 57 and $76^{\circ}C$ after adding salt (3% NaCl). Addition of Read Amity-N and corn starch to surimi showed new peak at the temperature of $90^{\circ}C\;and\;92^{\circ}C$, respectively. The enhancing effects of gel strengths of mackerel surimi cooked gels prepared from adding four kinds of additives, respectively, were egg white > soybean protein > Read Amity-N > corn starch in order. Scanning electron microscopy showed a difference in fine structures between the cooked gels which were prepared with and without additives. Dispersion profiles of protein were more thick in cooked gel prepared with additive than in cooked gel prepared without additive.

• Restorative Dentistry and Endodontics
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• v.43 no.2
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• pp.25.1-25.10
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• 2018

Objectives: To evaluate the mechanical properties and metallurgical characteristics of the M3 Rotary and M3 Pro Gold files (United Dental). Materials and Methods: One hundred and sixty new M3 Rotary and M3 Pro Gold files (sizes 20/0.04 and 25/0.04) were used. Torque and angle of rotation at failure (n = 20) were measured according to ISO 3630-1. Cyclic fatigue resistance was tested by measuring the number of cycles to failure in an artificial stainless steel canal ($60^{\circ}$ angle of curvature and a 5-mm radius). The metallurgical characteristics were investigated by differential scanning calorimetry. Data were analyzed using analysis of variance and the Student-Newman-Keuls test. Results: Comparing the same size of the 2 different instruments, cyclic fatigue resistance was significantly higher in the M3 Pro Gold files than in the M3 Rotary files (p < 0.001). No significant difference was observed between the files in the maximum torque load, while a significantly higher angular rotation to fracture was observed for M3 Pro Gold (p < 0.05). In the DSC analysis, the M3 Pro Gold files showed one prominent peak on the heating curve and 2 prominent peaks on the cooling curve. In contrast, the M3 Rotary files showed 1 small peak on the heating curve and 1 small peak on the cooling curve. Conclusions: The M3 Pro Gold files showed greater flexibility and angular rotation than the M3 Rotary files, without decrement of their torque resistance. The superior flexibility of M3 Pro Gold files can be attributed to their martensite phase.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.2
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• pp.219-226
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• 2020

Over the last decades, great efforts have been devoted to reuse industrial wastes and by-products from various industries as supplementary cementitious materials in order to reduce carbon dioxide(CO₂) emission by reducing the use of Portland cement in construction. Oyster shell waste, originating from the fishery industry, is available in huge quantities in certain areas, and is generally discarded or landfilled. In this study, we aimed to reuse oyster shell as an alternative to limestone in limestone calcined clay cement(LC³). The oyster shell calcined clay cement(OC³) paste were produced and were characterized via X-ray diffraction, isothermal calorimetry, compressive strength tests, and thermogravimetry. The results revealed that OC³ pastes exhibited similar strength development and reactivities by pozzolanic reaction with LC³, which implies that oyster shell could be used as a substitute for limestone in LC³.

• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.227-234
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• 1999

Solid dispersions were prepared to increase the dissolution rate of biphenyl dimethyl dicarboxylate (DDB) using water-soluble carriers such as povidone, copolyvidone, $2-hydroxypropyl-{\beta}-cyclodextrin (HPCD)$, sodium salicylate or sodium benzoate by solvent evaporation method. Solid dispersions were characterized by infrared spectrometry, differential scanning calorimetry (DSC) and powder X-ray diffractometry, dissolution and permeation studies. DDB tablets (7.5 mg) were prepared by compressing the powder mixtures composed of solid dispersions, lactose, com starch, crospovidone and magnesium stearate using a single-punch press. DDB capsules (7.5 mg) were also prepared by filling the mixtures in empty hard gelatin capsules (size No.1). From the DSC and powder x-ray diffractometric studies, it was found that DDB was amorphous in the HPCD or copolyvidone solid dispersions. Dissolution rates after 10 min of DDB alone and solid dispersions (1 : 10) in sodium benzoate, sodium salicylate and copolyvidone were 11.8, 23.5, 22.8 and 82.5%, respectively. Dissolution rates of DDB after 30 min from 1 : 10 and 1 : 20 copolyvidone solid dispersions were 80.5 and 95.0%, respectively. For the DDB tablets prepared using solid dispersions (1 : 20), the initial dissolution rate was dependent on carrier material, and was ranked in order, $Kollidon\;30\;{\ll}$ copolyvidone < HPCD. For the HPCD solid dispersion tablets, dissolution rate reached 97.4% after 15 min, but thereafter slowly decreased to 80.7% after 2 hr due to the precipitation of DDB. However, in the case of copolyvidone solid dispersion tablets, dissolution increased linearly and reached 93.4% after 2 hr. Reducing the volume of test medium from 900 to 300 ml markedly decreased the dissolution rate of the tablets containing 1 : 20 HPCD solid dispersions and 1 : 10 copolyvidone solid dispersion. For 1 : 20 copolyvidone solid dispersion tablets, there was no significant change in dissolution rate up to 1 hr with different volumes of test medium. Preparation of the copolyvidone solid dispersion (1 : 20) in capsules markedly delayed the dissolution (31.2 % after 2hr) due to the limited diffusion within capsules. The permeation rate $(13.4\;g/cm^2\;after\;8\;hr)$ of DDB through rabbit duodenal mucosa from copolyvidone solid dispersion (1 : 10) was markedly enhanced, when compared with drug alone or physical mixtures. From overall findings, DDB formulations containing copolyvidone solid dispersions (1 : 20) could be used to remarkably improve the dissolution rate in dosage form of powders and tablets.

• Polymer(Korea)
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• v.28 no.5
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• pp.404-411
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• 2004

The microcapsules containing triphenyl phosphate (TPP), a flame retardant, were prepared by phase-inversion emulsification technique using the epoxy resin (Novolac type) with excellent physical properties and network structure. This microencapsulation process was adopted for the protection of TPP evaporation and wetting of polymer composite during the polymer blend processing. The TPP, epoxy resin and mixed surfactants were emulsified to oil in water (O/W) by the phase inversion technology and then conducted on the crosslinking of epoxy resin by in-situ polymerization. The capsule size and size distribution of TPP capsules was controlled by mixed surfactant ratio, concentration and TPP contents, The formation and thermal property of TPP capsules were measured by differential scanning calorimetry and thermogravimetric analysis. The morphology and size of TPP capsules were also investigated by scanning and transmission electron microscopies. As the surfactant concentration increased, the TPP capsules were more spherical and mono-dispersed at the same weight ratio of mixed surfactants (F127: SDBS).

• Korean journal of food and cookery science
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• v.24 no.5
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• pp.636-644
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• 2008

The principal objective of this study was to assess the effects of hydrocolloids(xanthan gum, guar gum, sodium alginate, k-carrageenan, carboxy-methyl cellulose) on the suppression of retrogradation in the bread. The pasting properties of the doughs and the sensory properties were determined in the bread samples, to which xanthan gum, guar gum, sodium alginate, k-carrageenan, and CMC, were added at different ratios(0.2%, 0.6%, 1%). CMC and k-carrageenan with 0.6% level were selected for the further retrogradation studies. Changes in the firmness of the bread samples at room temperature for 15 days were assessed using a texture analyzer, and the type of retrogradation was calculated via the Avrami equation. The thermal properties of the samples were also determined via differential scanning calorimetry (DSC). The addition of hydrocolloids was shown to increase the viscosities of the doughs. Setback and breakdown viscosity were reduced significantly via the addition of CMC(0.6%, 1%), xanthan gum(1%), and k-carrageenan(1%). Sensory hardness was significantly increased when 1% hydrocolloids were added. Our textural analysis showed that the addition of CMC reduced the firmness of the bread, whereas k-carrageenan didn't. However, the retrogradation rate was reduced via the addition of k-carrageenan, as was also demonstrated in the results of our DSC analysis.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.787-793
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• 1998

Physicochemical properties of starch of three cultivars of Korean kidney Bean Starches, Pink (PKB), Red (RKB) and White (WKB) were studied. Starch granule was oval/round and smooth in all samples. The amylograms showed a continuous increase of viscosity without peak during heating. The water-binding capacities of starches of PKB, RKB and WKB were 102.1%, 94.7% and 106.9%, respectively. The swelling powers were rapidly incresed in all samples. The amylose content, blue value and relative viscosity of kidney bean starches were $31.1{\sim}32.8%,{\;}0.64{\sim}0.66$ and $2.27{\sim}2.61{\;}mlg^{-1}$, respectively. The transmittance of starch suspension was linearly increased as the temperature raised from $65^{\circ}C{\;}to{\;}85^{\circ}C$. The gelatinization temperature ranges determined by differential scanning calorimetry (DSC) were $71.1{\sim}86.9^{\circ}C for PKB, $71.1{\sim}86.0^{\circ}C$ for RKB and $60.8{\sim}77.9^{\circ}C$ for WKB.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1285-1290
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• 2000

The objective of this study was to evaluate the characteristics on the thermal denaturation of free drip released from pork loin during chilled storage using DSC (differential scanning calorimetry) with pH, concentration of NaCl and phosphate. The increasing of pH stabilized the heat resistance of the proteins in drip. A $T_1$ greatly increased of $T_{max}$ by $6.33^{\circ}C$ incline from pH 5.5 to 6.5. And increasing the concentration of NaCl destabilized the heat resistance of drip. $T_1$ showed the greatest reduction of $T_{max}\;(9.41^{\circ}C)$ in the presence of 5% NaCl. The presence of STPP (Sodium Tripolyphosphate) enchanced the thermal stability of pork drip by $5.84^{\circ}C$ in the presence of 0.5% STPP. As temperature increased from 40 to $100^{\circ}C$, lightness $(L^*)$ increased from 41.1 to 69.5, while redness $(a^*)$ decreased from 26.70 to 5.40. Particularly, both values of $L^*-$ and $a^*-$ greatly changed by 78% from 40 to $60^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.27-33
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• 2016

Phenolic resin has excellent heat resistance and good mechanical properties as a thermosetting resin. However, its thermosetting characteristics cause it to produce a non-recyclable waste in the form of sprue and runner which is discarded and represents up to 15~20% of the overall products. Forty thousand tons of phenolic resin sprue and runner are disposed of (annually). The (annual) cost of such domestic waste disposal is calculated to be 20 billion won. In this study, discarded phenol resin scraps were pulverized and treated by silanes to improve their interfacial adhesion with HDPE. The sizes of the pulverized pulverulent bodies and fine particles were (100um~1000um) and (1~100um), respectively. The pulverized phenol resin was treated with 3-(methacryloyloxy) propyltrimethoxysilane and vinyltrimethoxy silane and the changes in its characteristics were evaluated. The thermal properties were evaluated by DSC and HDT. The mechanical properties were assessed by a notched Izod impact strength tester. When the silane treated phenol resin was added, the heat distortion temperature of HDPE increased from $77^{\circ}C$ to $96^{\circ}C$ and its crystallinity and crystallization temperature also increased. Finally, its impact strength and tensile strength increased by 20% and 50%, respectively, in comparison with the non-treated phenol resin.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.687-691
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• 1993

Complexation of $Cd^{2+},\;Pb^{2+}\;and\;Hg^{2+}$ ions with four cryptands were studied by potentiometry and solution calorimetry in various weight percent methanol-aqueous solvent at 25${\circ}$C under $CO_2$free nitrogen atmosphere. The stabilities of the complexes were dependent on the cavity size of macrocycles. The $Hg^{2+}$ ion stability constants are higher than those of $Cd^{2+}\;and\;Pb^{2+}$ ion. All the cryptands formed complexes having 1 : 1 (metal to ligand) mole-ratio except for $Hg^{2+}-L_1$ (cryptand 1,2b: 3,5-benzo-9,14,17-trioxa-1,7-diazabicyclo-(8,5,5) heptadecane) and $Cd^{2+}-L_2$ (cryptand 2,2b: 3,5-benzo-10,13,18,21-tetraoxa-1,7-diazabicyclo (8,5,5) eicosane) complexes. $Hg^{2+}-L_1$ complex was a sandwitch type, and the $Cd^{2+}-L_2$ complex showed two stepwise reactions. Thermodynamic parameters of the $Cd^{2+}-L_2$ complex were $6.08(log\;K_1)$, -7.28 Kcal/mol $({\Delta}H_1)$, and $4.78\;(log\;K_2)$, -4.62 Kcal/mol $({\Delta}H_2)$, respectively, for 1 : 1 and 2: 1 mole-ratio. The sequences of the selectivity were increased in the order of $Hg^{2+}\;>Pb^{2+}\;>Cd^{2+}$ ion for $L_3\;and\;L_4$ macrocycles, and the $L_2$-macrocycle has a selectivity for $Cd^{2+}$ ion relative to $Zn^{2+},\;Ni^{2+},\;Pb^{2+}\;and\;Hg^{2+}$ ions. Thus, it is expected that the $L_2$ can be used as carrier for seperation of the post transition metals by macrocycles-mediated liquid membrane because $L_2$ is not soluble in water, and the difference of stability constants of the metal complexes with $L_2$ are large as compared with the other transition metal complexes. The $^1H\;and\;^{13}C-NMR studies indicated that the nitrogen atoms of cryptands have greater affinity to the post transition metal ions than the oxygen atoms, and that the planarities of the macrocycles were lost by complexation with the metal ions because of the perturbation of ring current of benzene molecule attached to macrocycles and counter-anions.