• Fibers and Polymers
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• v.4 no.4
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• pp.145-150
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• 2003

Polypropylene nonwoven fabrics were exposed to He/$O_2$ atmospheric pressure glow discharge plasma. Surface chemical analysis and contact angle measurement revealed the surface oxidation by formation of new functional groups after plasma treatment. Weight loss (%) measurement and scanning electron microscopy analysis showed a significant plasma etching effect. It was investigated in low-stress mechanical properties of the fabrics using Kawabata Evaluation System (KES-FB). The surface morphology change by plasma treatment increased surface friction due to an enhancement of fiber-to-fiber friction, resulting in change of other low-stress mechanical properties of fabric.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.188-191
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• 2003

In this wort. the effect of anodic oxidation on surface characteristics of high strength PAN-based carbon fibers is investigated in terms of surface and mechanical interfacial properties of the composites. As a result, the acidity of carbon fiber surfaces is increased, due to the development of oxygen functional groups in the presence of anodic oxidation. Also. it is found that the critical stress intensity factor ($K_{IC}$) is improved in the oxidized fibers-reinforced composites. which can be attributed to the good wettability between fibers and epoxy resin matrix.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.851-856
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• 1996

Copper Phthalocyanine (CuPc) thin films were fabricated on the silicon wafers by plasma activated evaporation method and structural analysis were carried out with various spectroscopies. The CuPc films had dense and smooth morphology and they also showed good mechanical properties and chemical resistance. The main molecular structure of the CuPc, which is the conjugated aromatic heterocyclic ring structure, was maintained even in the plasma process. However, metal-ligand (Cu-N) bands were deformed by the plasma process and the structure became amorphous especially at higher process pressures. Oxygen impurities were incorporated in the film and carboxyl functional groups were formed at the peripheral benzene ring. The structure and morphology of the films were dependent on the process pressure but relatively irrespective of the RF power.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.8-8
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• 2011

During the last half decade, chemically modified graphene (CMG) has been studied in the wide range of applications, such as polymer composites, energy-related materials, sensors, 'paper'-like materials, field-effect transistors (FET), inks, actuators, and biomedical applications due to its excellent electrical, mechanical, and thermal properties. Chemical modification of graphene oxide, which is generated from graphite oxide, which is produced by simple oxidation of graphite, has been a promising route to achieve mass production of CMG platelets via their colloidal suspensions. Graphene oxide contains a range of reactive oxygen functional groups, which renders it a good candidate for use in the aforementioned applications (among others) through chemical functionalizations. In this presentation, I will discuss my recent research activities on the fundamental chemistry of graphite oxide, as well as novel applications based on CMGs. Topics will include the chemical structure of CMGs and colloidal suspensions of CMG platelets, as well as a wide variety of applications.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.817-824
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• 1997

Stabilization is a key stage in the production of advanced carbon/carbon composites (ACC) from mesophase pitch, to render the mesophase infusible and the prevention of puffing during the subsequent carbonization. It is generally known that stabilization process as well as properties of mesophase pitch has a great deal of influence on the properties of the resultant ACC. Hence, it is possible to infer the properties of ACC by examing the stabilized mesophase pitch. In this study, extractions by solvents or acidified solvents extraction were carried out from the A-240 petroleum pitch. The extracted pitches were made into mesophase by heat treatments. Oxidative stabilization by air and non-oxidative stabilization by a chemical free radical initiator were performed. When a soluble polymer is fully stabilized, it should become insoluble in solvents. This phenomenon was used to estimated the degree of stabilization. The non-oxygen stabilized mesophase pitch powder was compared with the air stabilized mesophase pitch powder. FTIR provided additional information on the functional groups.

• Journal of the Korean Chemical Society
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• v.13 no.1
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• pp.56-61
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• 1969

By the chemical procedure and infra-red spectroscopy, the characteristics of humic acid were studied. The results were as follows: 1. Molecular weight. 5,200. 2. Molecular formula. $C_{240}H_{250}O_{120}N_{1O}$. 3. Rational formula. 4. Confirmation of the accurate structure of humic acid is beyond us nowadays. The structure is speculated that it may be a kind of condensed polymer of many benzene kerns in which above mentioned various functional groups are attached. Also some part of the large quantities of oxygen would be furan type carbonyl and aliphatic ethereal forms.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.113-119
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• 2021

Polypropylene fiber has the advantages of light weight, heat retention and antibacterial properties, but it is difficult to expand its market because it cannot be dyed or imparted functionality due to its hydrophobic properties. Atmospheric pressure plasma processing can modify the surface of the fiber and create polar functional groups on the surface of the fiber. In this study, an experiment was conducted on the hydrophilization of the ultra-hydrophobicity of polypropylene through plasma processing and surface changes before and after plasma processing. The ultra-hydrophobicity of polypropylene is the cause of impossible for dyeing and imparting functionality. Untreated polypropylene became hydrophilic, and it was confirmed that the ratio of oxygen and carbon(O/C) increased about 11 times from untreated polypropylene 0.017 to plasma-treated polypropylene 0.190.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.704-723
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• 2000

This study was undertaken to evaluate the tensile bond strength of In-Ceram alumina core treat-ed by ion assisted reaction(IAR). Ion assisted reaction is a prospective surface modification technique without damage by a keV low energy ion beam irradiation in reactive gas environments or reactive ion itself. 120 In-Ceram specimens were fabricated according to manufacturer's directions and divided into six groups by surface treatment methods of In-Ceram alumina core. SD group(control group): sandblasting SL group: sandblasting + silane treatment SC group: sandblasting + Siloc treatment IAR I group: sandblasting + Ion assisted reaction with argon ion and oxygen gas IAR II group: sandblasting + Ion assisted reaction with oxygen ion and oxygen gas IAR III group: sandblasting + Ion assisted reaction with oxygen ion only For measuring of tensile bond strength, pairs of specimens within a group were bonded with Panavia 21 resin cement using special device secured that the film thickness was $80{\mu}m$. The results of tensile strength were statistically analyzed with the SPSS release version 8.0 programs. Physical change like surface roughness of In-Ceram alumina core treated by ion assistad reaction was evaluated by Contact Angle Measurement, Scanning Electron Microscopy, Atomic Force Microscopy; chemical surface change was evaluated by X-ray Photoelectron Spectroscopy. The results as follows: 1. In tensile bond strength, there were no statistically significant differences with SC group, IAR groups and SL group except control group(P<0.05). 2. Contact angle measurement showed that wettability of In-Ceram alumina core was enhanced after IAR treatment. 3. SEM and AFM showed that surface roughness of In-Ceram alumina core was not changed after IAR treatment. 4. XPS showed that IAR treatment of In-Ceram alumina core was enabled to create a new functional layer. A keV IAR treatment of In-Ceram alumina core could enhanced tensile bond strength with resin cement. In the future, this ion assisted reaction may be used effectively in various dental materials as well as in In-Ceram to promote the bond strength to natural tooth structure.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.195-201
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• 2017

To study the effect of oxyfluorination on water dispersion of phthalocyanine blue(C.I. pigment blue 15:3), the pigment was oxyfluorinated using various oxygen to fluorine ratio of the reactant gas. After the oxyfluorination of the phthalocyanine blue pigment, no significant change in FT-IR spectra was observed, whereas XPS spectra showed the introduction of oxygen and fluorine containing functional groups. This suggests that the oxyfluorination of the pigment only occurred on the surface of the pigment particle and resulted in no significant change in UV-Vis spectra of the pigment. However, the oxyflurinated pigments showed improved water dispersion, compared to the non-treated pigment. Especially, when the oxygen to fluorine ratio was 47:3, the water dispersion of the oxyfluorinated pigments significantly increased, compared to the non-treated pigments. This suggests that the oxyfluorination of the phthalocyanine blue pigment has a potential to be used as a water dispersion improving method.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3327-3332
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• 2010

We investigated the effects of newly synthesized 4-[(butylsulfinyl)methyl]-1,2-benzenediol (SMBD) on the prevention of atherosclerosis in hypercholesterolemic rabbits. SMBD exhibited stronger inhibition of $Cu^{2+}$-induced low-density lipoprotein oxidation than that of ascorbic acid or simvastatin. Three-month-old rabbits were fed an atherogenic diet containing 0.5% cholesterol and 10% coconut oil, while other two groups were given an atherogenic diet with intravenous injection of either simvastatin or SMBD (0.33 mg/kg/day) for 4 weeks. The concentrations of plasma cholesterol and thiobarbituric acid reactive substances were significantly decreased in SMBD groups, compared to the control group. Also, aortic lipid level in the SMBD group significantly lower than that in the control group. Furthermore, compared with the control group, the SMBD group significantly inhibited the increase of aortic intimal thickness by 36% via reducing of aortic reactive oxygen species and cyclooxygenase-2 protein levels. We conclude that raised antioxidant effect of SMBD results in significant prevention against hypercholesterolemia.