• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.246-246
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• 2012

Smart catalyst design though novel catalyst preparation methods can improve catalytic activity of transition metals on reducible oxide supports such as titania by enhancement of metal oxide interface effects. In this work, we investigated Pt nanoparticles/titania catalysts under CO oxidation reaction by using novel preparation methods in order to enhance its catalytic activity by optimizing metal oxide interface. Arc plasma deposition (APD) and metal impregnation techniques are employed to achieve Pt metal deposition on titania supports which are prepared by multi-target sputtering and Sol-gel techniques. In order to tailor metal-support interface for catalytic CO oxidation reaction, Pt nanoparticles and thin films are deposited in varying surface coverages on sputtered titania films using APD. To assess the role of oxide support at the interface, APD-Pt is deposited on sputtered and Sol-gel prepared titania films. Lastly, characteristics of APD-Pt process are compared with Pt impregnation technique. Our results show that activity of Pt nanoparticles is improved when supported over Sol-Gel prepared titania than sputtered titania film. It is suggested that this enhanced activity can be partly ascribed to a very rough titania surface with the higher free metal surface area and higher number of sites at the interface between the metal and the support. Also, APD-Pt shows superior catalytic activity under CO oxidation as compared to Pt impregnation on sputtered titania support. XPS results show that bulk oxide is formed on Pt when deposited through impregnation and has higher proportion of oxidized Pt in the form of $Pt^{2+/4+}$ oxidation states than Pt metal. APD-Pt shows, however, mild oxidation with large proportion of active Pt metal. APD-Pt also shows trend of increasing CO oxidation activity with number of shots. The activity continues to increase with surface coverage beyond 100%, thus suggesting a very rough and porous Pt films with higher active surface metal sites due to an increased surface area available for the reactant CO and $O_2$ molecules. The results suggest a novel approach for systematic investigation into metal oxide interface by rational catalysts design which can be extended to other metal-support systems in the future.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.212-212
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• 2011

In addition to the catalysts' activity and selectivity, the deactivation of catalysts during use is of practical importance. It is crucial to understand the phenomena of the deactivation to predict the loss of activity during catalyst usage so that the high operational costs associated with catalyst replacement can be reduced. In this study, the activity of Ru catalysts, such as nanoparticles (3~6 nm) and polycrystalline thin film (50 nm), have been investigated under CO oxidation and oxidative/reductive reaction conditions at various temperatures with the ambient pressure X-Ray photoelectron spectroscopy (APXPS). With APXPS, the surface oxides on the catalyst are measured and monitored in-situ. It was found that the Ru film exhibited faster oxidation-and-reduction compared to that of nanoparticles showing mild oxidative-and-reductive characteristics. Additionally, the larger Ru nanoparticles showed a higher degree of oxide formation at all temperatures, suggesting a higher stability of the oxide. These observations are in agreement with the catalytic activity of Ru catalysts. The loss of activity of Ru films is correlated with bulk oxide formation, which is inactive in CO oxidation. The Ru nanoparticle, however, does not exhibit deactivation under similar conditions, suggesting that its surface is covered with a highly active ultrathin surface oxide. Since the active oxide is more stable as nanoparticles than as a film, the nanoparticles showed mild oxidative/reductive behavior, as confirmed by APXPS results. We believe these simultaneous observations of both the surface oxide of Ru catalysts and the reactivity in real time enable us to pinpoint the deactivation phenomena more precisely and help in designing more efficient and stable catalytic systems.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.304-304
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• 2010

The study on the catalytic oxidation of carbon monoxide (CO) to carbon dioxide ($CO_2$) using the noble metals has long been the interest subject and the recent progress in nanoscience provides the opportunity to develop new model systems of catalysts in this field. Of the noble metal catalysts, we selected ruthenium (Ru) as metal catalyst due to its unusual catalytic behavior. The size of colloid Ru NPs was controlled by the concentration of Ru precursor and the final reduction temperatures. For catalytic activity of CO oxidation, it was found that the trend is dependent on the size of Ru NPs. In order to explain this trend, the surface oxide layer surrounding the metal core has been suggested as the catalytically active species through several studies. In this poster, we show the influence of surface oxide on Ru NPs on the catalytic activity of CO oxidation using chemical treatments including oxidation, reduction and UV-Ozone surface treatment. The changes occurring to UV-Ozone surface treatment will be characterized with XPS and SEM. The catalytic activity before and after the chemical modification were measured. We discuss the trend of catalytic activity in light of the formation of core-shell type oxide on nanoparticles surfaces.

• Journal of muscle and joint health
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• v.20 no.3
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• pp.189-196
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• 2013

Purpose: The purpose of this study was to investigate electromyographic (EMG) activity of deep and superficial trunk muscles during trunk stabilization exercises with and without stabilization maneuvers. Methods: The relative muscle activity ratios and local muscle activities of 25 healthy males were measured using the 8 channel surface EMG system (Myosystem 1400A, Noraxon Inc., U.S.A). The surface EMG activities were tested during performing abdominal hollowing maneuver (AHM), abdominal bracing maneuver (ABM) and no stabilization maneuver (NSM) in random order. Data were analyzed using $1{\times}3$ repeated measures ANOVA. Results: During bridging exercises, the EMG activity ratio of transverse abdominis/internal oblique abdominis relative to rectus abdominis was significantly lower in NSM than in AHM and ABM. During bridging and kneeling exercises, the EMG activity ratio of multifidus relative to erector spinae was significantly higher in AHM than in NSM. Conclusion: The AHM can be clinically used by the physical therapist to activate selectively the trunk muscles when designing selective training programs for patients.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.1
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• pp.25-34
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• 2017

Purpose : The purpose of this study was to identify comparison of the abdominal muscle thickness and activity by using tool and unstable surface which is accompanied bridge exercise doing abdominal drawing-in breath. Method : This study was performed on normal 13 males and 17 females subjects doing bridge exercise accompanied abdominal drawing-in breath used tools. At this time muscle thickness and muscle activity is measured through ultrasound and EMG. Result : The results of this study, rectus abdominis, internal oblique and transverse abdominis showed a significant difference in muscle thickness when performed using pilates circle. And external oblique showed a significant difference muscle thickness when performed using gym ball. Rectus abdominis and external oblique showed a significant difference in muscle activity when performed using pilates circle. And internal oblique showed a significant difference in muscle activity when performed using sling. Conclusion : Therefore it is suggested that it would be effective to apply the gymball and pilates circle in the unstable surface for abdominal weakness.

• Nano
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• v.13 no.10
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• pp.1850117.1-1850117.11
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• 2018

Sulfated $TiO_2$ nanoparticles were successfully immobilized on zeolite through improving hydrolysis-deposition method. Microstructure, crystallization, surface state and surface area of composite catalysts were characterized by SEM, XRD, FTIR spectra, XPS and BET and the photocatalytic activity was evaluated by degradation of methyl orange under UV irradiation. We optimized these factors ($SO^{2-}_4$ ions, calcination temperature and loading amount of sulfated $TiO_2$) on photocatalytic activity and crystallization of composite photocatalysts. The results indicated that the $SO^{2-}_4$ ions are successfully immobilized on the surface of $TiO_2$, and sulfated $TiO_2$/zeolite show the highest photocatalytic activity for methyl orange at the $[SO^{2-}_4 ]/[Ti^{4+}]$ molar rate of 1:1, calcination temperature of $600^{\circ}C$ for 2 h, and sulfated $TiO_2$ loading amount of 40%, respectively.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.323-328
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• 2009

Cryotin F could be used for hydrolyzing shrimp byproducts into bioactive ingredients, which could be used as value-added products. The objective of this study was to investigate the optimum condition for antioxidative activities of the enzymatic hydrolysate produced with Cryotin F using response surface methodology with central composite rotatable design. Shrimp byproducts (shells and heads) were hydrolyzed with Cryotin F. The experimental ranges of the independent variables for 20 experimental runs were 28.2-61.8${^{\circ}C}$ reaction temperature, pH 6-10 and 0.5-5.5% enzyme concentration. The degree of hydrolysis for the reaction products was measured. Their antioxidative activities were measured using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity and Fe-chelating activity. The experimental method with central composite rotatable design was well designed to investigate the optimum condition for biofunctional ingredients with antioxidative activities using Cryotin F because of their high R2 values of 0.97 and 0.95 for DPPH-scavenging activity and Fe-chelating activity, respectively. Change in enzyme concentration did not significantly affect their antioxidative activities (p<0.05). Both DPPH scavenging activity and chelating activity against Fe for the enzyme hydrolysates were more affected by the pH of enzyme hydrolysis than by their action temperature. DPPH-scavenging activity was higher at acidic pH than alkali pH, while chelating activity against Few was inversely affected. Hydrolysate of shrimp byproducts showed high antioxidative activities depending on the treatment condition, so the optimum treatment of enzymatic hydrolysate with Cryotin F and other proteases can be applied to shrimp byproducts (shells) and other protein sources for biofunctional ingredients.

• Journal of Ginseng Research
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• v.40 no.3
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• pp.229-236
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• 2016

Background: Extraction conditions greatly affect composition, as well as biological activity. Therefore, optimization is essential for maximum efficacy. Methods: Korean Red Ginseng (KRG) was extracted under different conditions and antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content evaluated. Optimized extraction conditions were suggested using response surface methodology for maximum antioxidant activity and extraction yield. Results: Analysis of KRG extraction conditions using response surface methodology showed a good fit of experimental data as demonstrated by regression analysis. Among extraction factors, such as extraction solvent and extraction time and temperature, ethanol concentration greatly affected antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content. The optimal conditions for maximum antioxidant activity and extraction yield were an ethanol concentration of 48.8%, an extraction time 73.3 min, and an extraction temperature of $90^{\circ}C$. The antioxidant activity and extraction yield under optimal conditions were 43.7% and 23.2% of dried KRG, respectively. Conclusion: Ethanol concentration is an important extraction factor for KRG antioxidant activity and extraction yield. Optimized extraction conditions provide useful economic advantages in KRG development for functional products.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.263-267
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• 1999

NO removal activity (per unit of mass) of the used catalyst was seriously decreased as low as 27% of the new catalyst. Since the surface area of the used catalyst was 63% of that of the new one, the mojor reason for the lessened activity of the used catalyst compared to the new one may be due to the decreased surface area by sintering and surface concentration of active materials. Poison may be regarded as another important factor, since it affect the active site of catalyst by heavy metals. To recycle the used catalyst, we focused on the removal of poisoning agents from the catalyst. By using $80^{\circ}C$ water for 30 min upto 2 h, the recycled catalyst demonstrated the best activity and efficiency, which may be due to the removal of both K and Na. Although the recovered activity (per unit of surface area) of the catalyst was 79% compared to the new one, the activity (per unit of mass) of the recovered catalyst was only 49% compared of the activity of fresh catalyst.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.316-321
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• 2010

Krill byproduct was hydrolyzed with Alcalase 2.4L to produce functional ingredients for high antioxidative activities against 1,1-dimethyl-2-picryl-hydrazyl (DPPH) radical and Fe. The objective of this study was to investigate the optimum condition for degree of hydrolysis and antioxidative activity of enzymatic hydrolysate produced with the commercial Alcalase using response surface methodology (RSM) with a central composite rotatable design (CCRD). The ranges of independent variables were pH 7.6~10.4 for initial pH and $50.9{\sim}79.1^{\circ}C$ for hydrolysis temperature and their dependent variables were degree of hydrolysis, Brix, amount of phenolic compounds, DPPH-scavenging activity and Fe-chelating activity. RSM with CCRD was well designed to investigate the optimum condition for functional ingredients with high antioxidative activities using Alcalase 2.4L because of their high $R^2$ values of the range of 0.93~0.99 except the $R^2$ value of 0.50 for the amount of total phenolic compounds. The optimum hydrolysis conditions were pH 9.5 and $62^{\circ}C$ for degree of hydrolysis (DH) and pH 9.1 and $64^{\circ}C$ for DPPH-scavenging activity by response surface methodology. The yield of DH and DPPH-scavenging activity were $14.1{\pm}0.5%$ and $10.5{\pm}0.2%$, respectively. It is advantageous to determine the optimum hydrolysis conditions of krill and its by-products for the creation of different kinds of food products, as well as to increase the usage of marine protein sources.