• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.1
• /
• pp.39-45
• /
• 2007

In this paper, a research has been conducted to find out the optimal combination of central meridian and scale factor of UTM-K to apply for the whole area of Korean peninsula. For this research, various combinations of central meridian and stale factor are set up and the cumulated level or distortion for each combination has been computed and compared to each other. In the case of using the central meridian and scale factor defined in the present UTM-K, the level of distortion shows about $47.0837{\times}10^{-2}$. On the other hand, the minimum distortion which is about $21.0495{\times}10^{-2}$ can be obtained when the $127^{\circ}26'$ for the central meridian and 0.99991 for scale factor are used for computation. Consequently, we can conclude that later result is the optimum combination of central meridian and scale factor for the Korean peninsula.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11a
• /
• pp.242-247
• /
• 1996

Flow oscillations in boiling channels induces a drastic reduction of the (critical heat flux) CHF or premature burnout. However, most of CHF works and correlations have been focused on stable flow conditions without considering flow oscillation. Therefore to improve the understanding on flow oscillation CHF, in this paper a new CHF correction factor to predict the CHF values under flow oscillation conditions has been developed from 126 experimental data. Also to investigate the dominant factor on flow oscillation CHF parametric trends are analyzed by using the developed correction factor. The overall mean accuracy ratio of the developed correction factor is 1.033 with a standard deviation of 0.195. The RMS errors 0.198. Its assessment shows that the predictions agree well with the experimental data within 25% error bounds.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.11
• /
• pp.925-929
• /
• 2009

In this study, $0.95(K_{0.5}Na_{0.5})NbO_3-0.05Li(Sb_{0.8}Nb_{0.2})O_3$ ceramics were investigated as a function of the amount of $Ag_2O$ addition in order to improve dielectric and piezoelectric properties of lead-free piezoelectric ceramics. With increasing the amount of $Ag_2O$ addition, density and electromechanical coupling factor ($k_p$) increased up to 0.2 wt.% $Ag_2O$ and decreased above 0.2 wt.% $Ag_2O$. At the sintering temperature of $1020^{\circ}C$, electromechanical coupling factor ($k_p$), density, dielectric constant (${\varepsilon}r$) and curie temperature (Tc) of ceramics with 0.2 wt% $Ag_2O$ showed the optimal values of 0.42, $4.33\;g/cm^3$, 738 and $393^{\circ}C$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.3
• /
• pp.194-199
• /
• 2011

In this study, non-stoichiometric 1-x$[(K_{0.5}Na_{0.5})_{0.97}(Nb_{0.96}Sb_{0.04})O_3]$ + x $CeMnO_3$ + 0.8 mol%CuO + 0.2 wt% $Ag_2O$ (x=0, 0.005) ceramics were prepared by a conventional mixed oxide and carbonate method, their dielectric and piezoelectric properties were investigated with the variations of sintering temperature. As $CeMnO_3$ substitution incereased, the density, piezoelectric constant($d_{33}$) and dielectric constant($\varepsilon_r$) were increased and the mechanical quality factor(Qm) was decreased. At the sintering temperature of $1100^{\circ}C$, the density, electromechanical coupling factor($k_p$), dielectric constant($\varepsilon_r$) and piezoelectric constant($d_{33}$) of 0.5mol% $CeMnO_3$ specimen showed the optimun values of 4.475 $g/cm^2$, 0.437, 552 and 166 pC/N, respectively. However, the mechanical quality factor($Q_m$) showed the minimum value of 380.

• Journal of Korean society of Dental Hygiene
• /
• v.15 no.6
• /
• pp.963-971
• /
• 2015

Objectives: The purpose of the study is to investigate the relationship between health factor, oral health factor and revalence of depression in Korea elderly by data from the 5th Korea National Health and Nutrition Examination Survey(KNHANES) 2012. Methods: The subjects were 10,938 elderly over 65 years old by rolling survey method and data were extracted from the 5th Korea National Health and Nutrition Examination Survey(KNHANES) 2012. Data of 1,421 elderly were finally selected and analyzed using kstrada. The questionnaire consisted of socio-demographical characteristics of the subjects, health factors, oral health factors and depression. The oral health factors included subjective perception of oral health, alcohol consumption, exercise, smoking, and toothache. Results: Health factors influencing on the prevalence of depression were subjective health(p<0.001), stress(p<0.001), and alcohol consumption(p<0.05). Oral health factors related to the prevalence of depression were subjective oral health(p<0.05), annual dental checkup(p<0.01), and speaking problem(p<0.01). Conclusions: It is necessary to develop the oral health promotion program for the elderly and help them maintain good quality of life and mental health.

• Journal of the Korean Ceramic Society
• /
• v.39 no.9
• /
• pp.890-895
• /
• 2002

Effect of the sintering time on the microwave dielectric properties of the layered Functionally Graded Materials(FGMs) of the Mg0.93Ca0.07TiO3(MCT) with (Ca0.3Li0.14Sm0.42)TiO3(CLST) ceramics was investigated. The dielectric constant of layered FGMs specimens showed a nearly constant value and did not change significantly with sintering time. The quality factor, however, was affected by the relative density and thermal stress developed in each dielectric layer. With an increase of the relative density and the decrease of the induced thermal stresses, quality factor of the layered FGMs specimens increased and the quality factor was incluenced sensitively by the change of compressive stress developed in MCT layers which had a lower thermal expansion coefficient than that of CLST. For the layered FGMs specimen sintered at 1300$^{\circ}C$ for 9h, the compressive stress developed in MCT layer showed the maximum value, which, in turn, the quality factor of the specimen was the minimum value.

• Tunnel and Underground Space
• /
• v.30 no.1
• /
• pp.87-97
• /
• 2020

Fracture toughness of rock is a constant that can indicate the initiation and propagation of cracks due to blasting, excavation, etc. Scaled model tests have been applied to the behavior of tunnels and the stability of limestone mines. Through the scaled model, damaged zone evaluation due to blasting is also carried out, and the scale factor is not applied to the failure-related factors. In this study, DCT (diametral compression test) and finite element method ATENA2D numerical analysis results were compared to determine whether the scale factor could be applied to the fracture toughness of rock. The theoretical values of the scale factor applied to the fracture toughness of the rock and the DCT test results and the numerical results are 0.21~0.46, 0.40, and 0.99MPa ${\sqrt{m}}$ respectively, so these three values should be considered when determining scale factor. It is necessary to derive a suitable scale factor in consideration of the length, time, and mass to which the scale factor is applied, as well as the values of the scale factor of major design factors such as uniaxial compressive strength and density.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.9
• /
• pp.3735-3740
• /
• 2015

Context: Insulin-like growth factor peptides play important roles in regulating cell growth, cell differentiation, and apoptosis, and have been demonstrated to promote the development of colorectal cancer (CRC). Objective: To examine the association of insulin-related biomarkers including insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) and C-peptide with CRC risk and assess their relevance in predictive models. Materials and Methods: The odds ratios of colorectal cancer for serum levels of IGF-1, IGFBP-3 and C-peptide were estimated using unconditional logistic regression models in 100 colorectal cancer cases and 100 control subjects. Areas under the receiving curve (AUC) and integrated discrimination improvement (IDI) statistics were used to assess the discriminatory potential of the models. Results: Serum levels of IGF-1 and IGFBP-3 were negatively associated with colorectal cancer risk (OR=0.07, 95%CI: 0.03-0.16, P for trend <.01, OR=0.06, 95%CI: 0.03-0.15, P for trend <.01 respectively) and serum C-peptide was positively associated with risk of colorectal cancer (OR=4.38, 95%CI: 2.13-9.06, P for trend <.01). Compared to the risk model, prediction for the risk of colorectal cancer had substantially improved when all selected biomarkers IGF-1, IGFBP-3 and inverse value of C-peptide were simultaneously included inthe reference model [P for AUC improvement was 0.02 and the combined IDI reached 0.166% (95 % CI; 0.114-0.219)]. Conclusions: The results provide evidence for an association of insulin-related biomarkers with colorectal cancer risk and point to consideration as candidate predictor markers.

• The Korean Journal of Food And Nutrition
• /
• v.30 no.1
• /
• pp.105-111
• /
• 2017

This study was performed to provide fundamental data on the convenience foods purchase according to the food-related lifestyle. The subject was 250 Chinese students in South Korea region through a self-administered questionnaire. A factor analysis extracted five comprising food-related lifestyle, which we named health seeking (factor 1), taste seeking (factor 2), easy seeking (factor 3), popularity seeking (factor 4) and safety seeking (factor 5). According to the results of the reliability analysis, the food-related lifestyle showed an average of 3.16 and 0.813 for Cronbach's alpha coefficient. There were significant differences for the selection of convenience foods according to health seeking (p<0.05). Also, the popularity seeking and easy seeking lifestyle factors showed significant differences for the reason the purchase criteria of convenience food (p<0.05). There was not significant differences in convenience foods of selection criteria according to health seeking, taste seeking, easy seeking, popularity seeking and safety seeking types (p<0.05). A significant positive result of the internal characteristics of convenience foods purchase (p<0.05) was shown for the health seeking and taste seeking. A significant positive result of the external characteristics of convenience food purchase (p<0.05) was shown for the health seeking, taste seeking and safety seeking. In the correlation between convenience food purchase factors, the correlation coefficient of nutrition and ingredients are highest with 0.46, 0.445 in cooking and price, 0.441 in ingredients and expiry date, 0.383 in brand and price, 0.361 in taste and easy. In conclusion, this study presented the desirable direction of convenience food consumption in Chinese students.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.243-251
• /
• 2019

This study was undertaken to validate and assess the reliability of the Korean version of professional quality of life scale (K-ProQOL) that measures the compassion satisfaction, compassion fatigue and burnout among clinical nurses in Korea. We conducted an internal consistency reliability and construct validity by applying confirmatory factor analysis using SPSS WIN (24.0) and AMOS (18.0). Survey data were collected from 210 nurses working at three tertiary hospitals located in Seoul. Reliable internal consistency was achieved for the K-ProQOL, with a Cronbach's alpha for the total scale and three sub scale values of 0.72-0.90. Factor loadings on three subscales of the 30 items considered ranged from 0.25 to 0.82. The model was validated by confirmatory factor analysis (RMSEA 0.05-0.1, GFI >0.7, CFI >0.7). The findings of this study demonstrate that the K-ProQOL has satisfactory construct validity and reliability to measure compassion satisfaction, compassion fatigue and burnout among clinical nurses in Korea. This is the first study assessing the validity and reliability of the Korean version of professional quality of life scale for clinical nurses in Korea.