• Korean Journal of Materials Research
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• v.20 no.8
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• pp.429-433
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• 2010

In this study, activated carbon (AC) as a carbon source was modified with different concentrations of cobalt chloride ($CoCl_2$) to prepare a Co-AC composite, and it was used for the preparation of Co-AC/$TiO_2$ composites with titanium oxysulfate (TOS) as the titanium precursor. The physicochemical properties of the prepared Co-AC/$TiO_2$ composites were characterized by $N_2$ adsorption at 77 K, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The photocatalytic treatments of organic dyes were examined under an irradiation of visible light with different irradiation times. $N_2$ adsorption data showed that the composites had decreased surface area compared with the pristine AC, which was $389\;m^2/g$. From the XRD results, the Co-AC/$TiO_2$ composites contained a mixturephase structuresof anatase and rutile, but a cobalt oxide phase was not detected in the XRD pattern. The EDX results of the Co-AC/$TiO_2$ composites confirmed the presence of various elements, namely, C, O, Ti, and Co. Subsequently, the decomposition of methylene orange (MO, $C_{14}H_{14}N_3NaO_3S$) and rhodamine B (Rh.B, $C_{28}H_{31}ClN_2O_3$) in an aqueous solution, respectively, showed the combined effects of an adsorption effect by AC and the photo degradation effect by $TiO_2$. Especially, the Co particles in the Co-AC/$TiO_2$ composites could enhance the photo degradation behaviors of $TiO_2$ under visible light.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.251-256
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• 2013

Multiwalled carbon nanotubes (MWCNTs) modified with Pd and $TiO_2$ composite catalysts were synthesized by the sol-gel method followed by solvothermal treatment at low temperature. The chemical composition and surface structure were characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Photocatalytic recycle degradation experiments were carried out under both UV and visible light irradiation in the presence of MWCNT/$TiO_2$ and Pd-MWCNT/$TiO_2$ composites. As expected, the nanosized Pd-MWCNT/$TiO_2$ photocatalysts had enhanced activity over the non Pd treated MWCNT/$TiO_2$ material in the degradation of a rhodamine B (Rh.B) solution. An increase in photocatalytic activity was observed and attributed to an increase in the photo-absorption effect by MWCNTs and the cooperative effect of Pd and $TiO_2$ nanoparticles. According to the recycled results, the as-prepared Pd-MWCNT/$TiO_2$ sample had a good effect on it.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.51-57
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• 2019

The objective of the study was to determine the mediation effects of hope and grit in the relationship between human rights damage and self-esteem. A sample of students was recruited from two universities in Korea. For data analysis, SPSS PC+ and SPSS PROCESS macro were used. Frequency, reliability, correlation and mediating effect analysis were performed. Bootstrap technique was done to verify the mediating effect. Results showed as follows. First, grit, self-esteem and hope were negatively correlated with human rights damage, but grit, self-esteem and hope were positively correlated with each other. Second, hope and grit mediated in the relationship between human rights damage and self-esteem. For further research, it was discussed how university students who experienced human rights abuses could use grit and hope to maintain their lowered self-esteem.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.293-298
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• 2009

Background/aim : Gallbladder stone is the most common disease of biliary tract. It is lead to acute abdominal pain. The cholecystitis which is caused by in gallbladder stone occurs frequently and the possibility of the gallbladder cancer comes to be high. Our study was designed to determine the prevalence and risk factors gallbladder stone in a population who community. Materials and Methods : We enrolled a total of 826 (male : 297, female : 529) persons who 60 or older in Jeju-do 10 places from 2008 July one months. The height, weight, liver function tests, lipid profile, fasting blood sugar, were all measurement. They had their gallbladder examined with using ultrasonography. Statistical significance was defined as a p-value less than 0.05. Results : Among 826 persons, gallbladder stone was found in 49 persons (5.9%). The male is 6.1% and the female is 5.8%, the male 1.03 times appeared more highly the female. The body mass index above of 23.0 kg/$m^2$ with the gallbladder stone was 69.3% (p<0.047). Conclusion : The gallbladder stone appeared highly according to age increases. The obesity is the risk factor of gallbladder stone. The weight management and diet control is a possibility of reducing a gallbladder stone creation.

• 한국문화재보존과학회:학술대회논문집
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• 2007.05a
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• pp.69-71
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• 2007

• Journal of the Chungcheong Mathematical Society
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• v.26 no.4
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• pp.831-842
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• 2013

In this paper, we investigate uniform Lipschitz and asymptotic stability for perturbed differential systems using integral inequalities.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.2
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• pp.335-345
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• 2014

In this paper, we investigate bounds for solutions of nonlinear perturbed functional differential systems.

• Journal of applied mathematics & informatics
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• v.32 no.5_6
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• pp.697-705
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• 2014

In this paper, we investigate bounds for solutions of the nonlinear functional differential systems.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.137-144
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• 1998

• Journal of the Chungcheong Mathematical Society
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• v.22 no.4
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• pp.635-643
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• 2009

We investigate h-stability of solutions of perturbed Volterra difference systems.