• Journal of Ginseng Research
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• v.34 no.3
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• pp.227-236
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• 2010

The objective of this study was to evaluate the potential use of ginseng leaf as a cosmetic material. In this research, we employed enzymatic treated ginseng leaf by using Ultraflo L to improve the recovery of ginsenosides from the ginseng leaf and studied the biological activities and skin safety of the enzymatic treated ginseng leaf for use as a cosmetic material. The total ginsenoside contents of the non-enzymatic treated ginseng leaf (NEGL) and Ultraflo L treated ginseng leaf (UTGL) were 271 and 406 mg/g, respectively. The level of metabolite ginsenosides (sum of Rg2, Rg3, Rg5, Rk1, compound K, Rh1, Rh2, and F2) was higher in UTGL (93.1 mg) compared to NEGL (62.4 mg) in one gram ginseng leaf extract. The increase in amounts of ginsenoside types in UTGL compared to NEGL was generally 140% to 157%. UTGL exhibited relatively higher 2,2-diphenyl-2-picrylhydrazyl hydrate ($IC_{50}$, 2.8 mg/mL) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt ($IC_{50}$, 1.6 mg/mL) radical scavenging activities compared to NEGL (4.8 mg/mL and 2.2 mg/mL). The UTGL group showed normalized hydrogen peroxide, lipid peroxidation and visual wrinkling grade induced-UVB exposure. The UTGL did not induce any adverse reactions such as erythema and edema on intact skin sites; however, some guinea pigs treated with UTGL on abraded skin sites showed very slight erythema. The primary irritation index (PII) score of UTGL was 0.05 and it was classified as a practically non-irritating material (PII, 0 to 0.5). In skin sensitization tests with guinea pigs, UTGL had a positive rate of skin sensitization at 40%, and the mean evaluation score was 0.4.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1011-1018
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• 2005

The influence of liquid shotcrete accelerators(alkali aluminate, two types of alkali-free) was investigated. Comparing to the existing alkali aluminate accelerator, new alkali-free accelerator, AF2, shortened initial and final setting of cement system, and after curing for 1 day compressive strength was analogous with others. On the other hand, compressive strength of specimen cured for 12 hour was the highest by the addition of alkali aluminate accelerator, but final strength was the lowest by that. But compressive strengths of AF1, AF2 were similar to Plain up to 28day. Further from XRD(X-Ray Diffractometer) and DSC(Differential Scanning Calorimeter) analyses, we confirmed that setting promoted by alkali aluminate was mainly because of Ca(OH)2(calcium hydroxide), but the accelerating behavior of alkali-free was influenced by the needle-like ettringite$(6CaO{\cdot}Al_2O_3{\cdot}3SO_3{\cdot}32H_2O)$ crystal.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1019-1024
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• 2005

To research effects of various chemical superplasticizers(Lignosulfonic acid, Naphthalene sulfonated formaldehyde condensate, melamine sulfonated formaldehyde condensate, and Polycarboxylate) on the hydration of cement, experiments involving XRD, SEM, and DSC have been analysed with cement paste specimens. Regardless of types and dosages of superplasticizers, hydration reaction of specimen applied superplasticizer was delayed to 3 day, but then it showed similarity to plain which don't add superplasticizer. Moreover, the hydrating rate of cement paste was retarded as dosage of superplasticizer was increased. Also, kinetics related with hydrate of cement paste was slow in order of lignosulfonic acid, polycarboxylate, melamine and naphthalene sulfonated formaldehyde condensate. Nevertheless, when all kinds of chemical admixtures were used, morphologies of these hydrates were denser and more uniform than those of plain.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.823-829
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• 1997

The patients visiting pediatric dental office have been being younger than the previous, and they were often combined with systemic disease. But, we aren't able to perform the verbal communication, because of their impediment and youthfullness. And, we can't carry out the behavior control via physical restraint, as the developed social structure and the attitude of children and their parents. So, the importance and concerning of conscious sedation using sedative medicine are increased by time and time. Among the various conscious sedation, Chloral Hydrate and Nitrous Oxide inhalation are most popularly used, and barbiturates, benzodiazepine, opioids and hydroxyzine are used often. But, these medications have some side-effects and adverse reactions, may be failed to sedate the children. And limited use of medically compromised patients, especially for ASA class III, IV or more dangerous patients. We, the Department of Pediatric Dentistry, Chosun University have met some dangerous situation due to unfavorable pharmacogenic reactions, but we can control the situation and get well healed results. The below results are common situations and their solutions during conscious sedation. 1. By the intravenous administration, thrombophlebitis is the most common side-effects, but it may be healed with time without any special treatment. 2. Under the definitive guidelines about conscious-sedation, we can perform a safe conscious sedation for ASA class III patients. 3. When adversed reaction of Benzodiazepine is occured, it could be cared effectively with benzodiazepine antagonist, named Flumazenil.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.53-59
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• 2012

In this study, strength and durability of a geo-polymer grout material(HIT) was investigated through unconfined compression strength tests(UCS)), scanning electron microscope(SEM), elution tests, and surface observations. UCS tests showed high initial strength and rapid continuous strength increments when compared to labile wasser glass(LW) and space grouting rocket system (SGR) grout materials, which showed strength reduction after 28 days. The higher strength was also reflected in SEM results which showed calcium silicate hydroxide(C-S-H) gels of the dense hydrate range, indicating higher strength and durability. Additionally, elution tests and grout surface observations showed HIT was in good condition and the decrease in weight was minor when under water for six months. LW and SGR showed the grout surface to be constricted and lower durability due to higher weight increase. These results and observations show HIT to be better suited for coastal structural applications than LW and SGR in long terms of strength and durability.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.525-532
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• 1998

The autism is a complex disorder, characterized language impairment, perceptual-motor difficulties, and social disturbance. The autistic children have hyperactivity, lack of communication' lack of cooperation, inappropriate patient/dentist interaction, so they require professionally recognized behavioral management technique during dental treatment such as behavior modification, phamacological agents, and general anesthesia. A behavior management technique can be chosen by factors such as the severity of autism and possible accompanying disabilities, degree of cooperation, oral and general conditions of children. A non-pharmacological behavior modification may be selected for the autistic children who are able to communicate with dentist with mild dental caries, without compromised medical history. In case of excessively hyperactive, destructive, antisocial, and/or severe communicative disorder, a sedation technic with chloral hydrate, hydroxyzine, midazolam or nitrous oxide gas might to be performed. General anesthesia is preferred for severe communicative and/or behavioral disorder, elder age, excessive dental care need, and living a remote area.

• Journal of the Korean Ceramic Society
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• v.56 no.5
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• pp.489-496
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• 2019

Cement-based thermal insulation material was manufactured using OPC, lime, anhydrite, and CSA cement in this study. The morphology and physical properties of the material were analyzed using XRD. All samples had ettringite, Ca(OH)₂, and CaCO₃ crystals. The XRD peak intensity of the ettringite and Ca(OH)₂ slightly increased with an increase in curing time from 3 to 7 days. The compressive strength values at 28 days of specimens 1-8 were in the range of 0.25-0.32 MPa, and the compressive strength values of specimens 3-8 were > 0.3 MPa. The coefficients of correlation between compressive strength and apparent gravity at 7 days and those between compressive strength and ettringite/Ca(OH)₂ XRD peak intensity at 28 days were above 0.8. That is, the compressive strength exhibited an influence on apparent gravity at 7 days and on hydrate at 28 days. The thermal conductivity of all specimens was 0.041-0.045 W/mK, and the highest value of thermal conductivity was shown by specimen 5. The coefficient of correlation between apparent gravity and thermal conductivity was 0.84. It was concluded that control of raw materials and hydrates must be considered for manufacturing of insulation materials. The cement-based thermal insulation material in this study could be used in construction fields.

• Resources Recycling
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• v.18 no.3
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• pp.42-48
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• 2009

Since there are $OH^-,\;[SiO_4]^{4-}$ ion of high concentration at early hydration in the system added with activator (NaOH+$Na_2OSiO_2$) in the blast furnace slag, different from cement hydration, hydration progresses fast without induction period and forms reaction rim around the blast furnace slag grain. $0.6{\mu}m$ reaction rim was formed around the blast furnace slag grain from the 1 day of reaction period, and the thickness of reaction rim increases over the reaction time, growing to $1{\mu}m$ on the 28 days. Unreacted blast furnace slag grain deformed from angular shape to the spherical shape. Mole ratio of Ca/Si tends to decrease from inside of blast furnace slag grain to reaction rim. Difference of Ca/Si mole ratio between reaction rim and inside the blast furnace slag grain decreased and generated hydrate was a poor crystalline CSH(I) with Ca/Si mole ratio less than 1.5.

• Corrosion Science and Technology
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• v.6 no.5
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• pp.227-232
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• 2007

The corrosion behavior of carbon steel (N80) in carbon dioxide saturated 1%NaCl solution with and without acetic acid or acetate was investigated by weight-loss test, electrochemical methods (polarization curve, Electrochemical impedance spectroscopy). The major objective is to make clear that the effect of acetic acid and acetate on the corrosion of carbon steel in $Co_2$ environments. The results indicate that either acetic acid or acetate accelerates cathodic reducing reaction, facilitates dissolution of corrosion products on carbon steel, and so promotes the corrosion rate of carbon steel in carbon dioxide saturated NaCl solution. All Nyquist Plots are consisting of a capacitive loop in high frequency region, an inductive loop in medial frequency region and a capacitive arc in low frequency region. The high frequency capacitive loop, medial frequency inductive loop and low frequency capacitive arc are corresponding to the electron transfer reaction, the formation/adsorption of intermediates and dissolution of corrosion products respectively. All arc of the measured impedance reduced with the increase of the concentration of Ac-, especially HAc. However, the same phenomenon is not notable after reducing pH value by adding HCl. HAc is a stronger proton donor and can be reduced directly by electrochemical reaction firstly. Ac- can't participate in electrochemistry reaction directly, but $Ac^-$ an hydrate easily to create HAc in carbon dioxide saturated environments. HAc is as catalyst in $Co_2$ corrosion. As a result, the corrosion rate was accelerated in the presence of acetate ion even pH value of solution increased.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.305-312
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• 2018

This study is about the development of a non-sintered binder (NSB) which does not require a sintering process by using the industrial by-products Phosphogypsum (PG), Waste Lime (WL) and Granulated Blast Furnace Slag (GBFS). In this report, through SEM analysis of the NSB paste hardening body, micropore analysis of paste using the mercury press-in method and microstructure observation were executed to consider the influence of the formation of the pore structure and the distribution of pore volume on strength, and the following conclusions were reached. 1) Pore structure of NSB paste of early age is influenced by hydrate generation amount by GBFS and activator. 2) Through observing the internal microstructure of NSB binder paste, it was found that the strength expression at early age due to hydration reaction was achieved with a large amount of ettringite serving as the frame with C-S-H gel generated at the same time. It was confirmed that C-S-H gel wrapped around ettringite, and as time passed, the amount generated continually increased, and C-S-H gel tightly filled the pores of hardened paste, forming a dense network-type web structure. 3) For NSB-type cement, the degree of formation of gel pores below $10{\mu}m$ had a greater influence on strength improvement than simple pore reduction by charging capillary pores, and the pore size that had the greatest effect on strength was micropores with diameter below $10{\mu}m$.