• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.517-524
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• 2018

This purpose of this research is to observe the influence of non-condensable gas (NCG) on a horizontal super-hydrophobic aluminum tube and compare it with a bare aluminum tube. To achieve super-hydrophobic characteristics, an aluminum tube was coated with a Self-Assembled Monolayer (SAM). The overall heat transfer coefficient U was used to represent the condensation performance. The NCG mass fraction was the main variable, and its range was 0.08 to 0.45. The condensation performance of the SAM tube and bare tube increased with decreasing mass fraction of NCG. The SAM tube showed 1.9 to 2.5 times larger dropwise condensation performance than the bare tube. When the mass fraction of NCG decreased in the SAM tube, the rate of increase of the SAM tube was lower because flooded condensation occurred. In addition, filmwise condensation occurred in the SAM tube when more active condensation was generated, and its performance was lower than that of the bare aluminum tube. The flooded and filmwise condensation in the SAM tube is explained by the pinning effect. In conclusion, controlling the condition of the condenser is necessary to improve the condensation performance by surface modification a SAM.

• Korean Journal of Veterinary Research
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• v.6 no.1
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• pp.10-17
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• 1966

The antigenecity of somatic substances of S. pullorum standard strain and variant strain extracted byheat treatment, acid treatment and their modification, ammonium sulfate saturation (60 per cent), trypsin digestion was tested by indirest hemagglutination test and precipitation test and following results were optained. 1. Teatment at $100^{\circ}C$ for an hour of the bacteria could extract the antigen of S. pullorum standard strain and variant strain which was demonstrable by hemagglutination reaction with the human a group and chicken red blood cell. 2. Trypsin digestion was more enhanced its antigenecity in acid extracted antigen of S. pullorum variant strain compare with the S. pullorum standard strain. 3. The extracted antigenic substances of S. pullorum standard strain existed chiefly in the elicited fraction of precipitate at the treatment of ammonium sulfate saturation and after trypsin digestion, its antigenecity was demonstrated by hemagglutination. 4. At the treatment of ammonium sulfate treatment, did not occur the precipicate in acid extracted antigens of S. pullorum variant strain, however, the heal extracted antigen, positive reactions were obtained in both of the precipitate and supernatant fraction of the S. pullorum variant strain by hemagglutination reaction. After trypsin digestion, these fraction also exhibited positive reactions. 5. Precipitation test also tested dub could not detect in any soft of the antigens.

• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.78-85
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• 2012

In order to improve the adhesion between poly-monochloro-para-xylylene (Parylene-C) film and Aluminum thin film, the surface of Parylene-C film was irradiated by ${O_2}^+$ and $Ar^+$ ion beam generated by duoplamatron ion source. The ion dose of $Ar^+$ and ${O_2}^+$ was changed from $5{\times}10^{14}$ to $1{\times}10^{17}/cm^2$ and the ion beam energy was 1 kV. Contact angles of water on Parylene-C modified by $Ar^+$ and ${O_2}^+$ ion irradiation decreased from $78^{\circ}$ to around $17^{\circ}$, and $9^{\circ}$, respectively. X-ray photoelectron spectroscopy analysis shows that the hydrophilic groups were formed on the surface of Parylene-C by chemical reaction between the unstable chains induced by the ion irradiation and oxygen ions or residual oxygen gas. The hydrophilic groups were identified as C-O bond, C=O bond and (C=O)-O bond. The cross cut tape test which was applied to characterize the adhesion between Al thin film and Parylene-C film modified by ${O_2}^+$ ions irradiation shows that the adhesion strength was improved as increasing ion dose.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.57-68
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• 2008

For improving water quality and hish habitat environment the targeted instream flows added to the field measurement of low flow at each reach along Wonju Cheon are calculated by depth, velocity, and the present lower channel width with considering the landscape, aquatic environment, and natural ecological function. Target instream flow increasing ranged from $0.03m^3/s$ of upstream to $0.90m^3/s$ of downstream according to the proposed depths of 0.10m to 0.30m and velocity of 0.2m/s. The methods for target instream flow increasing are base flow increasing by watershed management, non polluted discharge inflow from valley and combined sewer by sewerage system modification, and discharges from upstream reservoirs and detention basins near-by stream. The possible increasing flow rates are $0.19m^3/s$ to $3.42m^3/s$ which are 1.4 to 2.5 times of low flow to be measured which are the equivalent targeted instream flows along Wonju Cheon. The BOD-based water quality improvement are analyzed by QUAL2E. The habitat suitability indices by PHABSIM of Zacco temmincki as target species at middle stream of Wonju Cheon improve significantly by low flow increasing, which is very important to improve water quality and fish habitat.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.367-376
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• 2017

The purpose of this study was to identify the impact of empowerment on achievement in the team based learning by college nursing students and the mediation effects of co-regulation. A convenience sample of 243 subjects were recruited from one university in G city. And data were collected from May 23 to May 30, 2017. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's Correlation, Multiple regression analyses with SPSS 21.0 Program. The psychological empowerment showed a significantly positive correlation of co-regulation and achievement, co-regulation showed a significantly positive correlation of achievement. The factors affecting the achievement were co-regulation, psychological empowerment, improvement on cooperation and modification, grade, and explanatory power was 57.2%. Co-regulation had a partial mediating effect in the relationship between shared psychological empowerment and Achievement. This study provided basic data for developing the nursing education program to improve achievement. and it is necessary to repeat the study including various variables related to achievement of the task in the future.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.345-352
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• 2014

In this paper, the CAD data for the optimal shape design obtained by isogeometric shape optimization is directly used to fabricate the specimen by using 3D printer for the experimental validation. In a conventional finite element method, the geometric approximation inherent in the mesh leads to the accuracy issue in response analysis and design sensitivity analysis. Furthermore, in the finite element based shape optimization, subsequent communication with CAD description is required in the design optimization process, which results in the loss of optimal design information during the communication. Isogeometric analysis method employs the same NURBS basis functions and control points used in CAD systems, which enables to use exact geometrical properties like normal vector and curvature information in the response analysis and design sensitivity analysis procedure. Also, it vastly simplify the design modification of complex geometries without communicating with the CAD description of geometry during design optimization process. Therefore, the information of optimal design and material volume is exactly reflected to fabricate the specimen for experimental validation. Through the design optimization examples of elasticity problem, it is experimentally shown that the optimal design has higher stiffness than the initial design. Also, the experimental results match very well with the numerical results. Using a non-contact optical 3D deformation measuring system for strain distribution, it is shown that the stress concentration is significantly alleviated in the optimal design compared with the initial design.

• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.207-215
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• 2012

Soft carbons are prepared by heat-treatment of cokes with different amounts of phosphoric acid (2, 4.5, and 10 wt% vs. cokes) at $900^{\circ}C$ to be used as anode materials for lithium ion batteries. From electrochemical measurements combined with structural analyses, we confirm that abundant nano-pores are existed in the microstructure of soft carbons prepared with the phosphoric acid, which are responsible for further lithium ion storage. Significant increase in reversible capacity of soft carbon is attained in proportion to added amount of the phosphoric acid. We also demonstrate the effect of structural modification with phosphoric acid on electrochemical performance of soft carbon to elucidate the origin of additional capacity.

• Journal of Preventive Medicine and Public Health
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• v.42 no.5
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• pp.337-342
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• 2009

Background : Many previous studies have shown that elevated homocysteine in the serum is a well known risk factor for cardiovascular disease and this is associated with other risk factors for cardiovascular disease, but any Korean data on this is limited. Objectives : This study aimed to calculate the prevalence of hyperhomocysteinemia and to analyze the relation between elevated homocysteine and the lifestyle factors of Korean adults. Methods : We conducted a cross-sectional survey that included 650 men and 743 women (age range, 20 to 79 years) who were residents of Gwangju City in Gyeonggi-do. These subjects participated in the health interview and examination survey from November to December 2005. The total homocysteine, total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride in the serum were measured. All the participants had their body composition measured such as height and weight, and we obtained health-related behavioral information through the self-entry questionnaire. Results : Very right-handed skewed distributions of homocysteine were shown in men and women. The prevalence of hyperhomocysteinemia was 22.6% in men and 13.7% in women in Gwangju city. On the multiple logistic regression analysis, hyperhomocysteinemia was associated with age (OR=1.02, 95% CI=1.01-1.04), male gender (OR=1.60, 95% CI=1.02-2.52), severe general physical activity (OR=0.32, 95% CI=0.15-0.69) and nutrient consumption (OR=0.49, 95% CI=0.31-0.76). Conclusions : There is a great prevalence of hyperhomocysteinemia in adults of Gwangju City, Korea and it was associated with both genetic factors and lifestyle risk factors. This study can suggest that comprehensive lifestyle modification is needed in order to diminish the prevalence of hyperhomocysteinemia and to prevent CVD.

• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.99-110
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• 2007

Efficient and inexpensive hydrogen storage is an essential prerequisite for the utilization of hydrogen, one of the new and clean energy sources for $21^{st}$ century. In this review, several storage techniques are briefly reviewed and compared. Especially, adsorption/storage via physisorption at low temperature, by using nanoporous adsorbents, is reviewed and evaluated for further developments. The adsorption over a porous material at low temperature is currently investigated deeply to fulfill the storage target. In this review, several characteristics needed for the high hydrogen adsorption capacity are introduced. It may be summarized that following characteristics are necessary for high storage capacity over porous materials: i) high surface area and micropore volume, ii) narrow pore size, iii) strong electrostatic field, and iv) coordinatively unsaturated sites, etc. Moreover, typical results demonstrating high storage capacity over nanoporous materials are summarized. Storage capacity up to 7.5 wt% at liquid nitrogen temperature and 80 atm is reported. Competitive adsorbents that are suitable for hydrogen storage may be developed via intensive and continuous studies on design, synthesis, manufacturing and modification of nanoporous materials.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.4
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• pp.164-172
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• 2004

Water temperature, salinity, the phytoplankton community and population of a marine photosynthetic ciliate, Mesodinium rubrum (=Myrionecta rubra), were monitored every 0.5-2 weeks in Gomso Bay and the Geum River Estuary from September 1999 to December 2000. Patterns of temporal variation of the M. rubrum population and phytoplankton community were compared with each other in relation to the differences in temporal fluctuation patterns of the water temperature and salinity in the two study areas. Higher population densities and more frequent blooms of M. rub rum in the Geum River Estuary than those in Gomso Bay could be due to the relatively higher nutrient input by freshwater influx in the Geum River Estuary. In the Geum River Estuary which experience more abrupt and irregular fluctuations of salinity, M. rubrum with its greater tolerance to salinity change exhibited increased dominance while neritic diatoms such as Skeletonema costatum, Asterionellopsis glacialis, A. kariana, Chaetoceros debilis, Eucampia zodiacus, Paralia sulcata, Thalassiosira pacifica, T. nordenskioeldii showed decreased dominance compared with those in Gomso Bay. Thus, it is possible that M. rubrum replaces the dominant diatom species in coastal waters where artificial modification of coast lines as in the case of Saemankeum Reclamation Project should increase the frequency as well as the absolute scale of freshwater discharges.