• Korean Journal of Materials Research
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• v.8 no.10
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• pp.898-904
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• 1998

Ni-W alloys containing 10 to 50wt% W were prepared by electrodeposition. Tungsten content in the alloy increased with current density. X-ray diffraction analysis revealed that the alloy was crystalline phase when deposited at current densities lower than 50mA/${cm}^2$. Their crystal structure transformed to amorphous at higher current densities. In terms of tungsten content, the crystal -+ amorphous transition occurred at 40-46wt% which was identified by the 3 fold increase in the width of a diffraction peak. The lattice parameter of crystalline phase increased with W upto 40wt% which is higher than the solubility limit of W (about 30wt%) in Ni. Therefore, the alloys are considered to be Ni solid solution supersaturated with W. The amorphous Ni-W alloys were recrystallized by annealing them at temperatures over $400^{\circ}C$. This was evidenced by the appearance a strong [ 11 11 annealing texture. The supersaturated W was precipitated during the annealing at over $800^{\circ}C$. The current-density dependence of W content and crystallinity was utilized to produce alternating layers of crystalline (30wt% W) and amorphous (50wt%) phases which may exhibit unique mechanical and corrosion properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.399-402
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• 2000

For improvement of B constant in $CaMnO_3$-$CaTiO_3$ perovskite type thermistors, effect of $Cr_2$$O_3$ addition ranged from 0.0wt% to 5.0wt% on electrical properties were investigated with contents and sintering temperatures in the view of crystal and microstructures. The solubility limit of Cr$_2$O$_3$was up to 0.5wt% judging from the result of lattice parameter. The grain size was decreased and the resistance at room temperature and B constant were increased with the addition of $Cr_2$$O_3$.On particular, B constant of$CaMnO_{3-x}$$Cr_2$$O_3$ system was increased greatly from 1574k to 2598k at 0.5wt% $Cr_2$$O_3$addition. Further addition of $Cr_2$$O_3$, however, resulted in the decrease of the resistance and B constant due to the $Cr_2$$O_3$ precipitation on the grain boundary. As the$CaTiO_3$contents increased in the $CaMnO_3$-$CaTiO_3$ system, the resistance at room temperature and B constant were highly changed.

• Membrane Journal
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• v.25 no.6
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• pp.547-557
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• 2015

In this study, we synthesized polyimide with high carbon dioxide gas transport property using 2,2-bis(3,4-carboxylphenyl) hexafluoropropane, 2,3,5,6-tetramethyl-1,4-phenylenediamine and poly(ethylene glycol) bis(3-aminopropyl) terminated and then we calculated solubility parameter of synthesized polymer and non-solvent phase separation coefficient to determine proper solvent for preparation of asymmetric membrane, also we measured the viscosity of the polymer solution to check polymer contents in membrane solution and prepare asymmetric membrane with $LiNO_3$ additives. The morphology and gas separation property of membrane prepared by phase separation method was confirmed using Field Emission Scanning Electron Microsope and the single gas permeation measurement apparatus. We confirmed that the carbon dioxide permeance of the membrane increased and the selectivity showed little change with decreasing of the volatile solvent contents.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.187-193
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• 2019

Regarding physical absorption mechanism for fine particles(Dust), internal pore-bridging is a major parameter in porous media. In this paper, internal bridging pore system is invented through FA-based geopolymer and incorporated PLA (Polylactic Acid) fiber with biodegradability. With various mix proportions, compressive strength over 20MPa is obtained but PLA is little dissolved in the condition of NaOH 5mole and $30^{\circ}C$ of temperature, which was found that temperature rising accelerates PLA solubility. Within 24hours, beads type PLA is completely dissolved under $90{\sim}130^{\circ}C$ and NaOH 5~12mole of alkali. In room condition, geo-polymerization is limitedly occurs so that the internal pore after PLA dissolution is thought to be effective to absorption and storage of fine particles.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.6
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• pp.881-890
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• 2019

Objective: A study was conducted to develop non-dairy creamer analogs/mimics using egg white, egg yolk, soy protein and their combinations, and their nutrient content, shelf-life and flavor acceptability were compared. Methods: Spray dried egg white, egg yolk, and soy protein isolate were purchased from manufacturers and used for the formulae. Results: The protein contents of the non-dairy creamer analogs/mimics were about 8.5% as calculated. The amounts of oleic and linoleic acid content increased as the amount of yolk increased in the formula, but the increases of polyunsaturated fatty acids were <0.5% of total fat. Addition of egg yolk to the formula increased choline and lutein content in the products, but the amounts were <0.4 mg/g for choline and $4{\mu}g/g$ for lutein. The lutein in the products continued to decrease over the storage time, and only about 15% to 20% of the 0-month amounts were left after 3 months of storage. Although the thiobarbituric acid reactive substances values of the spray-dried non-dairy creamer analogs/mimics increased as storage time increased, the values were still low. Yellowness, darkness, and egg flavor/odor of the non-dairy creamer analogs/mimics increased as the amount of egg yolk in the formula increased. The overall acceptability of the non-dairy creamer analogs/mimics was closely related to the intensity of egg flavor/odor, but storage improved their overall acceptance because most of the off-odor volatiles disappeared during the storage. Water temperature was the most important parameter in dissolving spray-dried non-dairy creamer analogs/mimics, and $55^{\circ}C$ to $75^{\circ}C$ was the optimal water temperature conditions to dissolve them. Conclusion: Higher amounts of yolk and soy protein combinations in place of egg white reduced the cost of the products significantly and those products contained better and balanced nutrients than the commercial coffee creamers. However, off-flavor and solubility were two important issues in the products.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1357-1364
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• 2000

Our study was performed to evaluate the effect of leaching parameters including the physicochemical characteristics and the fractionated composition of heavy metals on the release of heavy metals in fly ash discharged from MSWI. Leaching parameters such as pH, CEC, particle size, and exchangeable fraction among the fractional composition classified by sequential extraction procedure are considered. The leaching rate of heavy metal released by KSLT method is largely dependent on the pH of fly ash. The effect of pH on the release of heavy metals is different from elements. It appears that the leaching rate of cadmium and copper decreases with increasing pH, while lead and zinc increases at the condition of neutral or strong alkali condition, which suggests that the leaching of heavy metals are limited by the solubility. It is found that the effect of CEC is similarly to that of pH, $D_{10}$ among the particle size of fly ash is negative correlated with the concentration of heavy metals leached by KSLT method. In the case of exchangeable fraction, the leaching rate of heavy metals is linearly correlated with the exchangeable fraction for the fly ash below 40 meq/l00g of CEC, but not related out of the range.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.451-458
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• 2013

The physicochemical properties and cooking qualities of four rice varieties (Goami, Giant-embryonic rice, Baegjinju, Aranghyangchal) which grown under ecofriendly farming as development of material for chronic disease tailored instant rice and porridge, respectively, were investigated. The contents of crude protein, crude lipid and crude fiber were the highest in Goami. The water absorption rate of Aranghyangchal at $85^{\circ}C$ was higher than other rice. However on rice flour, the water absorption rate and solubility of all functional rices at $85^{\circ}C$ were higher than control (brown rice flour). In addition viscosity of all functional rices at $100^{\circ}C$ were higher than control (brown rice flour). In spite of brown rice, Aranhyangchal showed no significant differences about hardness of Ilpum (white rice). The sensory evaluation was shown that Aranghyangchal was the highest in glossiness, flavor, roasted nutty taste, cohesiveness and overall preference. Although Giant-embryonic rice and Baegjinju were brown rice, overall preference was higher than Ilpum (white rice). These study results were showed that the functional rices could be good to make instant rice.

• Journal of Adhesion and Interface
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• v.18 no.3
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• pp.109-117
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• 2017

Poly(N-vinyl carbazole) (PVK) homopolymer, poly(4-vinylpyridine) (PVP) homopolymer, and PVK-b-PVP block copolymer were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and the polymers were used to prepare non-aqueous graphene dispersions with four different solvents, ethanol, N-methyl-2-pyrrolidone (NMP), dichloromethane (DCM), and tetrahydrofuran (THF). $^1H-$ and $^{13}C-NMR$ spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC) were carried out to confirm the chemical structure of the polymers. Stability of graphene dispersions was measured by on-line turbidity measurement. Time-dependent Turbiscan Stability Index (TSI) values were interpreted in terms of surface tension (${\sigma}$) and solubility parameter (${\delta}$) among solvents, polymers, and graphene. It was confirmed that the solubilities of polymer and surface tension between solvent and graphene affected the dispersion stability of graphene. PVK-b-PVP block copolymer could effectively maintain the low TSI values of graphene dispersions in ethanol and THF, which have been known as poor solvents for graphene dispersions. It can also be noted that DCM shows good dispersion stability comparable to NMP, which has been known as the best solvent for graphene dispersion.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.686-692
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• 2001

The effects of extrusion on solubilization of brown rice, glutinuous rice, barley and job's tear were analyzed by response surface methodology (RSM). Solubilization of whole grains by extrusion was characterized in terms of water solubility index (WSI), concentration of water soluble polysaccharides (C) and intrinsic viscosity $([\eta])$. Considering both concentration and intrinsic viscosity, a dimensionless target parameter $([\eta])$ was also included for analysing the extrusion effects on cereal extrusion. Response surface methodology analysis showed that the moisture content was the most significant contributor among screw speed, temperature and moisture content affecting the solubilizing phenomena of cereals processed with extrusion. Brown rice was not showed the significant relationship on $([\eta])$ because $([\eta])$ was more affected by intrinsic viscosity. The critical point of whole grains extrusion except brown rice was corresponded to screw speed of 300 rpm, moisture content of 20% and temperature of $120^{\circ}C$.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.180-189
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• 2017

Pharmaceutical co-crystals primarily to improve the solubility as well as stability of insoluble drug are to be investigated more intensively for IMDs as US FDA has reclassified co-crystal as a special case of solvates in August this year. In this study, we proposed a mechanism of indomethacin-saccharin co-crystal formation and the creation of transient indomethacin meta-stable form using in-line monitoring tools with the addition rate of anti-solvent as a critical process parameter. Among various instruments, we combined PVM (particle vision measurement) and FBRM (focused beam reflectance measurement) for the in-line monitoring of anti-solvent co-crystallization process. The off-line characterization of resulting powders was carried out employing the PXRD (powder x-ray diffraction) and DSC (differential scanning calorimeter). It was observed that the pathway to the final IMC-SAC co-crystal was significantly dependent upon the anti-solvent addition rate. The process conditions to obtain high quality co-crystal powder effectively were established. Consequently, we concluded that in-line monitoring combing the PVM and FBRM should be useful for the in-line monitoring of pharmaceutical co-crystallization processes.