• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.155-160
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• 2005

Removal of methyl mercaptan was investigated using adsorption on virgin activated carbon (VAC) and modified activated carbons with acidic chemicals in the present work. CAC, NAC, AAC and SAC were represented as activated carbons modified with HCI, HNO$_{3}$, CH$_{3}$COOH and H$_{2}$S0$_{4}$ ,respectively The pore structures were evaluated using nitrogen isotherm. The surface properties of virgin activated carbon and modified activated carbons were characterized by EA, pH of carbon surface and acid value from Boehm titration. The modification of activated carbon with acidic chemicals resulted in a decrease in BET surface area, micropore volume and surface pH, but an increase in acid value. The order of the adsorption capacity of activated carbons was NAC>AAC>SAC>CAC>VAC, and in agreement with that of acid value of activated carbons, whereas in disagreement with that of micropore volume of activated carbons. It appeared that chemical adsorption played an important role in methyl mercaptan on modified activated carbons with acidic chemicals compared to virgin activated carbon. Modifying activated carbon with acidic chemicals enabled to significantly enhance removal of methyl mercaptan.

• KSBB Journal
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• v.23 no.1
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• pp.70-76
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• 2008

Surface of hydrophobic media was modified to become hydrophilic by ion beam irradiation. Fixed bed biofilm reactors packed with or without surface modification were used to remove organics, nitrogen, and phosphorus from sewage. This system composed of anoxic/oxic cycles to increase the nutrient removal. A cylindrical polyethylene was used as a packing media in this study. With 12 hours of hydraulic retention time (HRT), the reactors with and without surface modification showed 95% and 92% $COD_{cr}$ removal, respectively. Both reactors showed over 95% $COD_{cr}$ removals for a longer HRT of 16 hours. Nitrogen removal ranged 54.8% to 70.2% for the surface modified system and 57.5% to 76.5% for the non-modified system under same condition. Finally, phosphorus removal ranged 59.4% to 69.8% for the surface modified system and 51.3% to 63.4% for the non-modified system under same condition. From this study organics and phosphorus were better removed in using surface modified media and vice versa for nitrogen removal.

• Journal of Periodontal and Implant Science
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• v.52 no.4
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• pp.261-281
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• 2022

Purpose: Short implants are a potential alternative to long implants for use with bone augmentation in atrophic jaws. This meta-analysis investigated the survival rate and marginal bone level (MBL) of surface-modified short vs. long implants. Methods: Electronic and manual searches were performed for articles published between January 2010 and June 2021. Twenty-two randomized controlled trials (RCTs) comparing surface-modified short and long implants that reported the survival rate with at least 1 year of follow-up were selected. Two reviewers independently extracted the data, and the risk of bias and quality of evidence were evaluated. A quantitative meta-analysis was performed regarding survival rate and MBL. Results: The failure rates of surface-modified short and long implants differed significantly (risk ratio, 2.28; 95% confidence interval [CI], 1.46, 3.57; P<0.000). Long implants exhibited a higher survival rate than short implants (mean follow-up, 1-10 years). A significant difference was observed in mean MBL (mean difference=-0.43, 95% CI, -0.63, -0.23; P<0.000), favoring the short implants. Regarding the impact of surface treatment in short and long implants, for hydrophilic sandblasted acid-etched (P=0.020) and titanium oxide fluoride-modified (P=0.050) surfaces, the survival rate differed significantly between short and long implants. The MBL differences for novel nanostructured calcium-incorporated, hydrophilic sandblasted acid-etched, and dual acid-etched with nanometer-scale calcium phosphate crystal surfaces (P=0.050, P=0.020, and P<0.000, respectively) differed significantly for short vs. long implants. Conclusions: Short surface-modified implants are a potential alternative to longer implants in atrophic ridges. Long fluoride-modified and hydrophilic sandblasted acid-etched implants have higher survival rates than short implants. Short implants with novel nanostructured calcium-incorporated titanium surfaces, hydrophilic sandblasted acid-etched surfaces, and dual acid-etched surfaces with nanometer-scale calcium phosphate crystals showed less marginal bone loss than longer implants. Due to high heterogeneity, the MBL results should be interpreted cautiously, and better-designed RCTs should be assessed in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.110-115
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• 2005

Plasma Transferred Arc Spray process was used to make modified surface for wear and corrosion resistant by using Co system powder type alloy. The modified surface was produced by changing only spray current and other process variables were constant. The current range was from 80 amp to 140 amp as inclosing 20 amp. It was appeared that the geometrical shape, microstructures and microhardness of the modified surface were affected by the different cooling rate of base metal. The modified surface that produced by 120 amp current exhibited the fine microstructure and the highest microhardness number impling good surface characteristics. It was also found that the spray current affected the width but not the height of the bead as increasing current.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.443-448
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• 2011

The propellant has a short shelf-life because of nitrogen oxides that were released from nitrocellulose decomposition. As-received and surface-modified ACFs were applied to remove the nitrogen oxides with intend to extend the shelf-life of propellant. The specific surface area of modified ACFs was slightly decreased but nitrogen function groups such as pyridine, pyridone and pyrrol were created on the surface of ACFs. As a result, the NO removal capacity of the surface-modified ACF by propellant waste increased about twice than that of the as-received ACF. The shelf-life of propellant was extended about 1.25 times by accompanying surface-modified ACF.

• Carbon letters
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• v.6 no.3
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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.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.41-56
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• 2008

The methods of surface modification of commercial implants were various according to the manufacturer. Surface modification of implant may produce diverse physical and chemical surface characteristics resulted from the treatment method and treatment condition. As a result, the bone response might be different. Even though surface modified implants have been used clinically, most researches are focusing on the bone response of surface modified implants comparing to machined implants rather than surface modified commercial implants. This study compare and analyze bone responses of 4 surface modified commercial implants with different shapes and surfaces. Eighty surface modified commercial implants with 4 different surface characteristics were installed in the tibia of white Newzealand rabbits. Biomechanical stability tests and histomorphometric evaluation were done. The results were as follows: 1. Surface modified commercial implants showed stable osseointegration at 6 weeks after installation. 2. Histomorphometric evaluation showed that there was no significant differences in bone to implant contact among 4 different commercial titanium implants. In comparing the implants with different shape the measurement of bone growth in subcortical area would be more reliable than entire bone to implant contact length. 3. Resonance Frequency Analysis showed that there was no significant differences among 4 types of implants, even though they were significantly different in installation. 4. There was significant differences in interfacial shear strength among 4 type of implants. 5. It is difficult to observe accurate bone to implant interface using Micro-CT. However, it is possible to measure the entire contact length of the implant to the bone.

• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.621-636
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• 1999

When mucoperiosteal flaps are positioned and sutured to desirable position, the wound contains several interface between tissues which differ fundamentally in composition & biological reaction. Thus the C-T surface of the flap will, on one hand, oppose another vascularized surface, and on the other, the avascular dental material for example, when root resoptions, fractured root, endodontic perforation, deep root carious lesions were filled with amalgam, glass ionomer, resin etc. Recently, a number of case report described the successful treatment of a subgingival root lesion with restorative material & free gingival graft, open flap surgery, but more objective research was needed . Most of study on restorative materials were concerned for cytotoxicity not for actual healing event on that materials and its influencing factors such as biocompatibility, surface wettability, surface topography . The aim of this in vitro study was to evaluate the effect of amalgam, resin modified glass ionomer, composite resin per se, and their surface roughness on the growth of human gingival fibroblast. The cells were obtained and placed on culture flask and incubated for 3 days with the prepared test materials. Then count the attached cell number with hemocytometer,(n=12) and 2 samples were examined with SEM about attachment cell morphology . Another 4 samples were evaluated on their surface roughness with Talysurf and average surface roughness value(Ra) were obtained. Statistical difference in attached cell number, roughness value were analyzed using ANOVA. The number of attached cell was as follows, for root dentin specimen 16.7${\pm}$4.41, resin modified glass ionomer 14.0${\pm}$4.15, resin 8.13${\pm}$3.63, amalgam 0.72${\pm}$3.33(${\times}10^3$). Between root dentin and resin-modified glass ionomer, no significant difference was observed, but resin, amalgam showed a significant less cell numbers than for root dentin, resin modified glass ionomer cement. SEM examination expressed many cell surface attachment apparatus in root dentin and resin modified glass ionomer specimens. For resin specimen, cell attachment was observed but exposed less appratus. The average surface roughness value are following results. Dentin specimen 0.6972${\pm}$ 0.104, resin modified glass ionomer 0.0822${\pm}$0.009, resin 0.0875${\pm}$0.005, amalgam 4.2145${\pm}$0.985(${\mu}m$). Between root dentin, resin-modified glass ionomer, and resin, no significant difference was observed, but amalgam showed a significant more rough surface than other groups. When evlauated the interrelationship between cell attachment and surface roughness, therefore, there was weak reverse correlation.(pearson correlation : - 0.593) These results suggest that resin modified glass ionomer have the favorable healing potential when used for subgingival restoration. And for relationship between cell attachment and surface characteristics, further investigations were needed.

• Corrosion Science and Technology
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• v.8 no.3
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• pp.103-109
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• 2009

An epoxy coating was designed to give a hydrophobic property on its surface by modifying it with three types of Amino Terminated Polydimethylsiloxane (ATP), and then effects of the modification on the structure, surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified epoxy coating were examined using FT-IR spectroscopy, hydrothermal cyclic test, and impedance test. The surface of epoxy coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between epoxy and modifier by the modification. The phase separation tendency is more appreciable when modified by ATP with higher molecular weight ATP at higher content. Water transport behavior of the modified epoxy coating decreased more in that with higher hydrophobic surface property. The resistance to localized corrosion of the modified epoxy coated carbon steel was well agreed with its water transport behavior and hydrophobic tendency.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.156-163
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• 2003

This research presents modeling of a functional surface which is a constructed free-formed surface. The modeling introduced in this paper adopts modified B-spline that is utilizing approximating technique. The modified B-Spline is constructed with altered control vertices. It is applied to measure points on a surface of an impeller blade. This research builds a surface-modeler accepting inputs of measured points. Generation of cutter-paths for NC machining employs the model of the constructed surfaces. The machined surfaces which is generated in several cases are compared in the aspect of machining accuracy.