• Carbon letters
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• 제6권3호
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• pp.166-172
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• 2005

The objective of this study was to investigate the possibility of application for water treatment using the zeocarbon. The zeocarbon was mixture of zeolite and activated carbon. In general, the application of commercial zeocarbon to water treatment is difficult because of weak strength in water and the high pH value of effluents after water treatment. Therefore, we have modified the surface of zeocarbon. For the surface modification, we used the acid treatment to make surface functional group. As a result of modification, was created functional group on zeocarbon surface and was formed mesopore in zeocarbon. The surface modified zeocarbon was applied to removal of nitrogen. In removal experiments of nitrogen, removal efficiency was very high. And, strength of zeocarbon after water treatment and pH of effluents were stabilized. This indicates that the surface modified zeocarbon was easy to recover and reuse. Consequently, our results were shown the possibility of application for water treatment using the surface modified zeocarbon.

• Membrane and Water Treatment
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• 제11권3호
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• pp.231-235
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• 2020

Industrialization and modern developments have led to an influx of toxic heavy metals into the aquatic environment, and the accumulation of heavy metals has serious adverse effects on humans. Among the various heavy metal treatment methods, adsorption is very useful and frequently used. Plastic materials, such as polypropylene and polyethylene, have been widely used as filter media due to their mechanical and chemical stability. However, the surface of plastic material is inert and therefore the adsorption capability of heavy metals is very limited. In this study, granular media and fiber media composed of polypropylene and polyethylene are used, and the surface modification was conducted in order to increase adsorption capability toward heavy metals. Oxygen plasma generated hydroxyl groups on the surface of the media to activate the surface, and then acrylic acid was synthesized on the surface. The grafted carboxyl group was confirmed by FT-IR and SEM. Heavy metal adsorption capability of pristine and surface modified adsorbents was also evaluated. Overall, heavy metal adsorption capability was increased by surface modification due to electrostatic interaction between the carboxyl groups and heavy metal ions. Fibrous PP/PE showed lower improvement compared to granular PP media because pore blockage occurred by the surface modification step, thereby inhibiting mass transfer.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1771-1773
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• 2007

Surface modification of the gate dielectric has a strong influence on the performance of printed transistors. The surface modification occurs between the gate dielectric and semiconductor. The printed transistor with evaporated vanadium pentoxide ($V_2O_5$) modification exhibits a mobility of $0.2cm^2\;V^{-1}\;s{-1}$ and a subthreshold slope of 1.47 V/decade.

• 한국표면공학회지
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• 제45권1호
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• pp.8-14
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• 2012

The effects of the alkali surface modification process on the adhesion strength between electroless-plated Cu and polyimide films were investigated. The polyimide surfaces were effectively modified by alkali surface treatments from the hydrophobic to the hydrophilic states, and it was confirmed by the results of the contact angle measurement. The surface roughness increased by alkali surface treatments and the adhesion strength was proportional to the surface roughness. The adhesion strength of Cu/polyimide interface treated by KOH + EDA (Ethylenediamine) was 874 gf/cm which is better than that treated by KOH and KOH + $KMnO_4$. The results of XPS spectra revealed that the alkali treatment formed oxygen functional groups such as carboxyl and amide groups on the polyimide films which is closely related to the interfacial bonding mechanism between electroless-plated Cu and polyimide films. It could be suggested that the species and contents of functional group on polyimide films, surface roughness and contact angle were related with the adhesion strength of Cu/polyimide in combination.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2747-2752
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• 2013

Surface modification of colloidal silica nanoparticles without disrupting the electric double layer of nanoparticles is a major challenge. In the work, silane was employed to modify colloidal silica nanoparticles without inducing bridge flocculation obviously. The effect of pH value of the silica sol, the amount of silane in feed, and reaction temperature on the graft amount and the final size of modified particles was investigated. The increased weight loss by TG and the appearance of $T_2$ and $T_3$ except for $Q_2$ and $Q_3$ signals by CP/MAS $^{29}Si$ NMR of the modified samples verified the successful grafting of silane. The graft amount reached 0.57 mmol/g, which was slightly lower than theory value, and the particle size remained nearly the same as unmodified particles for acidic silica sol at the optimum condition. For alkaline silica sol after modification, aggregates composed of several nanoparticles connected together with silane moleculars as the bridge appeared.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.282-289
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• 2010

In preparation of silica aerogel-based hybrid coating materials, the combination of hydrophobic aerogel with organic polar binder material is shown to be very limited due to dissimilar surface property between two materials. Accordingly, the surface modification of the aerogel would be required to obtain compatibilized hybrid coating sols with homogeneous dispersion. In this study, the surface of silica aerogel particles was modified by using both surfactant adsorption and heat treatment methods. Four types of surfactants with different molecular weights and HLB values were used to examine the effect of chain length and hydrophilicity. The surface property of the modified aerogel was evaluated in terms of visible observation for aerogel dispersion in water, water contact angle measurement, and FT-IR analysis. In surface modification using surfactants, the effects of surfactant type and content, and mixing time as process parameter on the degree of hydrophilicity for the modified aerogel. In addition, the temperature condition in modification process via heat treatment was revealed to be significant factor to prepare aerogel with highly hydrophilic property.

• Geomechanics and Engineering
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• 제6권2호
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• pp.139-151
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• 2014

Mudstone is a very common rock that, when in contact with water, can exhibit considerable volume change and breakdown. This behavior of mudstone is frequently encountered in geotechnical engineering and has a considerable influence on infrastructure stability. This is particularly important in the present work, which focuses on mitigating the harmful properties of mudstone. The samples studied are of Permian Age mudstone from Shandong Province, China. Modification tests using organic silicone additive material were carried out. The mechanisms of physical properties modification of mudstone were comparatively studied using corresponding test methods, and the modification mechanism of organic silicone additive material acting on mudstone was analyzed. The following conclusions were drawn. The surface texture and characters of mudstone changed dramatically, surface character turns from hydrophilic to hydrophobic after organic silicone additive material modification. The changes in the surface character indicate a reduction in the water sensitivity of mudstone. After modification, the shape of porosity and fracture of mudstone changed unremarkable, and the total and free expansion ratios decreased obviously, whereas the strength increased markedly.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1030-1033
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• 2004

We herewith report for the effect of dielectric surface modification on the electrical characteristics of organic thin-film transistors (OTFTs). The kist-jm-1 as an organic molecule for the surface modification is deposited onto the surface of zirconium oxide ($ZrO_2$) gate dielectric layer. The OTFTs are elaborated on the flexible plastic substrates through 4-level mask process to yield a simple fabrication process. In this work, we also have examined the dependence of electrical performance on the interface surface state of gate dielectric/pentacene, which may be modified by chemical properties in the gate dielectric surface.

• 한국생산제조학회지
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• 제9권2호
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• pp.66-71
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• 2000

Laser induced surface hardening of Tool steel(STC5) can be achieved either with or without surface melting. In trans-formation hardening as the surface is heated to a temperature below its melting point and is rapidly cooled solidified microstructures are usually much finer and stronger than those of the base matals. For this reason surface modification of tool steel by YAG laser irradiation has been studied as a function of processing parameters such as power density pulse width defocusing distance and molten depth. The high energy density changes and refines the microstructure of the near surface layer. In the case of beam passes martensite formed in the melt zone exhibited very high vickers hardness values. Molten depth and width depend on defocusing distance and energy of black color painting is more absorptive than other color painting.

• 한국생산제조학회지
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• 제23권6호
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• pp.576-579
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• 2014

Rails are continuously exposed to severe environments due to increases in train service frequency, passing tonnage, and speed. Wear is one of the most common types of damage observed on rails. The surface of railsis heat treated to secure safety at critical sites, such as curved tracks or turnouts. Ultrasonic nanocrystal surface modification (UNSM), a new approach for rails, was examined to strengthen the rail surface. The effect of UNSM on the wear resistance of rail specimens was compared with that of heat treatment. Wear resistance was improved after UNSM treatment due to increased hardness and surface compressive residual stress.