• The Journal of Korean Medicine
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• v.33 no.1
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• pp.42-51
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• 2012

Objectives: We measured the density of smoke and harmful gases emitted from burning adhesive indirect moxa. Through the test we aimed to find out if there was an excessive amount of smoke emitted and if it included harmful gases. Methods: 9 types of adhesive indirect moxa were chosen. The buffer layers which do not burn during treatment were removed and 10g of each moxa were made into powder and put into a holder. A smoke density chamber (Smoke Density Chamber FTT. U.K) and Fourier transform infrared spectroscopy (FT-IR I 4001. MIDAC U.S.A.) were used to measure the density of smoke and harmful gases emitted from burning moxa by ISO 5659-2 test. Results: The result of measuring maximum smoke density showed that the regular indirect adhesive moxa (A-F) emitted high density smoke of 172.1-291.4Ds. The smokeless moxas, Seoam moxas, emitted the least amount of 3.4-5.5Ds. Concentrations of 7 typical harmful gases (CO, HCl, HCN, HBr, HF, SO2, NOx) were measured and all of the moxas emitted CO due to incomplete combustion. 4 types of moxa emitted NOx and all smokless moxas emitted NOx. HBr, HCN, HCl, HF, SO2 were not found in any of the moxas. Conclusions: The amount of harmful gases emitted from burning moxa was much lower than short-term exposure standards of chemical and physical factors (Ministry of Labor 2010-44). Further experiments measuring gases from moxa combustion should be done in larger environments similar to normal medical clinics.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.165-171
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• 1998

The $Y_1Ba_2Cu_3O_{7-x}$(123) superconductor powders were prepared by pyrophoric synthesis method(PSM) using $Y_2O_3$(99.9%), $BaCO_3$(99.9%), and CuO(99.9%) powders. The phase formation and reaction kinetics of 123 superconductor manufactured with powders prepared in various pHs of pyrophoric synthetic solution have been studied through the experiments at various heat treatment temperatures and times. Inductively coupled plasma(ICP) spectroscopy and scanning electron microscopy(SEM) measurements were performed to examine the composition and morphology of the sample. X-ray diffraction(XRD) analysis was done to determine phase formation and conversion ratio of Y-Ba-Cu-O systems. The 123 powder prepared at pH 7(${\pm}0.3$) yields the best result in terms of purity, homogeneity, and reactivity. The activation energies(${\Delta}E_a$) of 123 phase formation were found to be 191 kJ/mol and 230kJ/mol in solid state reaction method and pyrophoric synthesis method, respectively.

• Journal of Life Science
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• v.20 no.9
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• pp.1385-1393
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• 2010

Three mold strains, Aspergillus oryzae (AOFAG), Aspergillus kawachii (AKFAG), and Monascus purpureus (MPFAG) were used for fermentation of Angelica gigas Nakai powder. The contents of polyphenolic compounds, flavonoids, minerals, decursin and decursinol angelate and the activities of DPPH (${\alpha},{\alpha}'$-diphenyl-$\beta$-picrylhydrazyl) free radical scavenging, reducing power, and tyrosinase were measured. The highest contents of phenolic compound and flavonoid were NFAG at 2.78% and MPFAG at 1.18%, respectively. Major minerals were K, Mg, Fe, Na and Ca. Decursin and decursinol angelate were the major ingredients of Angelica gigas according to HPLC analysis. Decursin area was higher in all fermented Angelica gigas than in NFAG. The activities of free radical scavenging and tyrosinase were stronger in all fermented Angelica gigas than NFAG. However, the Fe/Cu reducing powers were stronger in NFAG than all fermented Angelica gigas. Overall, these results may provide the basic data needed to understand the biological activities and chemical characteristics of Angelica gigas fermented by mold for the development of functional foods.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.159-163
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• 2002

A single phase perovskite relaxor ferroelectric PMN-PT-BT was prepared by a single calcination and the modified mixed oxide process. It was accomplished by ball-milling PbO, $Nb_2O_5,\;Ti(OC_3H_7)_4,\;BaCO_3,\;and\;Mg(NO_3)_2$ instead of MgO, removing the solvent, and then followed by calcination at 900$^{\circ}C$ for 2h. The specimen sintered at 1100$^{\circ}C$/2h showed the sintered density of 7.83 g/$cm^3$, room temperature dielectric constant of 22000, and dielectric loss of 2.5%. Addition of 1.0 mole% (0.3 wt%) of Ag as $AgNO_3$ and followed by calcination at 550$^{\circ}C$/2h lowered the sintering temperature to 900$^{\circ}C$. It still showed the sintered density of 7.88 g/$cm^3$, room temperature dielectric constant of 20000 and dielectric loss of 2.4%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.35-36
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• 2008

PTC thermistor are characterized by an increase in the electrical resistance with temperature. The PTC materials of middle Curie point were produced or that of high Curie point (above $200^{\circ}C$), it was determined that compositional modifications of $Pb^{2+}$ for $Ba^{2+}$ produce change sin the Curie point to higher temperature. PTC ceramic materials with the Curie point above $120^{\circ}C$ were prepared by adding $PbTiO_3$, PbO or $Pb_3O_4$ into $BaTiO_3$. Thereby, adding $Pb^{2+}$ into $BaTiO_3$-based PTC material to improve Tc was studied broadly, however, weal know that PbO was poisonous and prone to volatilize, then to pollute the circumstance and hurt to people, so we should dope other innocuous additives instead of lead to increase Tc of composite PTC material. In order to prepare lead-free $BaTiO_3$-based PTC with middle Curie point, the incorporation on $Bi_{1/2}K_{1/2}TiO_3$ into $BaTiO_3$-based ceramics was investigated on samples containing 0, 1, 2, 3, 4, and 50mol% of $Bi_{1/2}K_{1/2}TiO_3$. $Bi_{1/2}K_{1/2}TiO_3$ was compounded as standby material by conventional solid-state reaction technique. The starting materials were $Bi_2O_3$, $K_2CO_3$, $BaCO_3$ and $TiO_2$ powder, and using solid-state reaction method, too. The microstructures of samples were investigated by SEM, DSC, XRD and dielectric properties. Phase composition and lattice parameters were investigated by X-ray diffraction.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.50-57
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• 2015

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of a by-products such as fly ash and ground granulated blast-furnace slag to partially replace the cement in concrete are gathering momentum. Many researchs on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the sources of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of $CO_2$ gas. In this study, we investigated the influence of the fluidity, air content and compressive strength of mortar on alkaline activator in order to develop cementless fly ash and ground granulated blast-furnace slag based alkali-activated mortar with superplasticizer. In view of the results, we found out that Pn of fluidity and compressive strength is the best in four type of superplasticizer, and PNS of powder type of fluidity is better than that of liquid type in the case of AA.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.159-164
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• 2013

A white powder-like substance, so called 'bloom', is formed on the surface of fruits of many varieties of cucumber. Although it is a natural phenomenon, bloomed fruits are accepted lower in quality compared to bloomless fruits by consumers. The experiments were conducted to obtain basic informations for breeding rootstocks, and to develop promising bloomless rootstocks from basic source materials collected and selected by seed company. The surfaces of bloomless fruits were appeared on the bladder cell of glandular trichome and the epicuticular waxes. Those of bloom fruits appeared with an injured bladder cell and many particles, which were not seen on those of bloomless fruits. The chromaticity was investigated on the surface of the bloom and the bloomless fruits. The 'a' and 'b' value of the bloom and the bloomless fruits did not show any significant difference. The 'L' value was significantly different and that of bloom fruits was higher than that of bloomless fruits. Fruit Si content was conspicuously lower in the fruits of cucumber plants grafted on the bloomless rootstock than in the fruits of those grafted on general bloom rootstocks.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.416-422
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• 2020

In this study, eco-friendly biodegradable materials were prepared using poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT), and hydrogenated castor oil power (HCO) as an additive. The prepared PLA/PBAT/HCO blended films were characterized by the scanning electron microscope (SEM) and fourier-transform infrared spectroscopy (FT-IR). The results of SEM analysis indicated that PLA/PBAT (8 : 2) blended films added HCO showed no rough area, crack, or large agglomeration when compared with those adding various additives (12-hydroxy stearic acid (12HSA) and cellulose). The FT-IR results indicated the presence of specific peak of HCO in the PLA/PBAT blended films, and its peak intensity increased with increasing HCO content (0~5.0 wt%). Tensile strength, elongation at break, and water barrier and thermal properties of the prepared PLA/PBAT/HCO blended films were also investigated, indicating that the physical and thermal properties was improved more than three times by the addition of HCO. The biodegradability test in soil revealed that the prepared biodegradable materials were degraded by about 6.0~20% after 90 days.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.298-307
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• 2019

Two types of CaO-Al₂O₃-SiO₂ (CAS) glass powder applied spray coating on the surface of sintered Al₂O₃ were researched for sintering behavior; (1) Si-rich, glass containing high content SiO₂, (2) Ca-rich, containing high content CaO. Foaming of bubbles remaining inside the Ca-rich glass was produced at a viscosity of approximately 10⁷~10⁹ poise, resulting in decreasing shrinkage (interfering with sintering) and increasing surface roughness. In case of Si-rich glass, there was no serious foaming bubbles phenomenon like Ca-rich below 1000℃, however cristobalite crystals with low density occurred at 1200℃ and then produced re-foaming of bubbles, resulting in abnormal sintering behavior. These phenomenon is considered to be a decrease in viscosity due to an increase in the Ca content of the glass according to the formation of low-density cristobalite crystals. Therefore, in case of CAS glass, it is necessary to consider the increase of surface roughness and the sintering interference because of foaming bubbles phenomenon at low temperature sintering. Especially, when containing high SiO₂ content, abnormal foaming phenomenon due to crystallization at high temperature should be predicted.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.41-62
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• 2003

In this research, we manufactured the paste opaque porcelains using Propylene Glycol (PG) and Buthylene Glycol (BG) as a solvent, and compared the composition of solvents, the coefficient of thermal expansion, the particle size distribution, the viscosity and bonding strength to metal, and the tone with those of the commercial products(Duceram Plus, Duceram GmbH; VMK 95, Vita Co.; Noritake EX-3, Noritake Co.)used in the clinical field. The results of the research were as follows: 1. The result of solvent analysis indicated that the solvents included in the paste opaque porcelains of the control group were mainly composed of Glycols. 2. From the Coefficient of thermal expansion measurement, we drew out the following results; testing group: $14.0\times10^{-6}/^{\circ}C$, Duceram Plus: $13.9\times10^{-6}/^{\circ}C$, VMK 95: $14.3\times10^{-6}/^{\circ}C$, and Noritake EX-3: $13.3\times10^{-6}/^{\circ}C$. 3. Seen from the result of particle size distribution measurement, the experimental group was similar to the control group in 1$\mu m$ below, but the experimental group marked the highest distribution of 61% in the case of between 1$\mu m$ and 5$\mu m$. Between 5$\mu m$ and 10$\mu m$, they showed relatively similar distribution, and Noritake EX-3 was turned out the highest distribution of 29% in 10$\mu m$ above. 4. From the result of viscosity measurement, Duceram plus showed the highest viscosity throughout all the measurements followed by Noritake Ex-3, experimental group and VMK 95 in decreasing order. 5. The result of bonding strength measurement was EX 35.53 $\beta\acute{A}$, DU 40.88 $\beta\acute{A}$, VM 39.43 $\beta\acute{A}$, and NO 35.39 $\beta\acute{A}$, and no significant difference was found between the experimental group and the control groups(P>0.05). 6. The measurement of the tone indicated that the $L^*$ value of the experimental group was 86.89 0.63 in average, which is higher than the control group in its brightness. In the case of the $a^*$ value, Duceram Plus, VMK 95 and EX-3 showed positive value, whereas the testing group was turned out negative value. In $b^*$ value, Duceram Plus proved the highest. From the results of this research, the paste opaque porcelains using Propylene Glycol (PG) and Buthylene Glycol (BG) as a solvent did not make differences from the commercial products that are actually used in the clinical fields. Therefore, it is possible to utilize Propylene Glycol (PG) and Buthylene Glycol (BG) for the paste opaque porcelains of P.F.M crown. It is also recommended that further researches concerning the compositions and forms of powder, the types of organic solvent components and the ratio of mixture proceeded in order to improve the level of productivity in the future.