• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.352-357
• /
• 2003

Creep tests for Titan were carned out using constant-load at $600^{\circ}C$, $650^{\circ}C$ and $700^{\circ}C$. Material constants necessary to predict creep life were acquired from the experimental creep data. And the applicability of Monkman-Grant(M-G) and modified M-G relationships was discussed. It was discovered the log-log plot of M-G relationships between the rupure time(tr) and he minimum creep rate(${\varepsilon}_m$) was conditional on test temperatures. The slop of m was 2.75 at $600^{\circ}C$ and m was 1.92 at $700^{\circ}C$. However; the log-log plot of modified M-G relationships between $t_r/\varepsilon_r$ and $\varepsilon_m$ was indpendent on stresses and temperatures. That is the slop of m' was almost 3.90 in all the data. Thus, change M-G relationships to creep life prediction could be vtilized more reasonably than that of M-G relationships for type Titan. It was divided that the constant slopes never theless of temperatures of practical stresses in the modified relationship were due to an intergranular break grown by wedge-type cauities.

• Bulletin of the Korean Chemical Society
• /
• v.11 no.4
• /
• pp.297-302
• /
• 1990

Retention of mono-substituted phenols in reversed-phase liquid chromatography has been studied based on the linear solvation energy relationships using the solvatochromic mobile phase parameters, ${\pi}_m^{\ast}, {\alpha}_m$ and ${\beta}_m$. It has been observed that retention behavior of phenols in RPLC were well represented by regression equations vs. solvatochromic mobile phase parameters even though the equations may be incomplete due to lack of an explicit cavity term. Dependence of retention of monosubstituted phenols on the mobile phase properties were varied depending on the type of the organic cosolvent in the mobile phase, e.g., ${\beta}_m$ and {\alpha}_m$ in methanol-water system, but ${\pi}_m^{\ast} and ${\beta}_m$ in THF-water system. It has been suggested that retention of phenols in methanol-water system is controlled by the solvophobicity of the mobile phase.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.4
• /
• pp.601-611
• /
• 2010

Currently, a life cycle cost estimates(LCCE) is the most important factor in weapon system acquisition process. However, operation and maintenance(O&M) cost related studies are insufficient from the previous literature survey. O&M cost consists of various cost factors such a man power, maintenance and direct & indirect support costs. We have known that spare-parts cost is a key factor in the O&M cost. In this paper, we developed the spare-parts cost estimating relationships(CERs) of fixed-wing aircraft and armored vehicle weapon systems which include 4 historical cost drivers ; system acquisition cost, deterioration rate, localization rate, mission characteristic. Furthermore, we proposed the application methodologies that O&M cost estimating, total life cycle cost estimating and determination of the economic life using the spare-parts CERs.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.10 no.2
• /
• pp.142-145
• /
• 2010

We introduce the concept of IVF almost M-continuity and investigate characterizations for such mappings on the interval-valued fuzzy topological spaces. We study the relationships between IVF almost M-continuous mapping and IVF compactness.

• Korean Journal of Adult Nursing
• /
• v.17 no.2
• /
• pp.230-238
• /
• 2005

Purpose: The purposes of this study were to explore the concept of uncertainty and to examine the relationships among uncertainty, appraisal of uncertainty, depression, anxiety, and perceived health status in patients with atrial fibrillation. Method: The study utilized a descriptive correlational survey design using a face to face interview method. A convenience sample of 49 subjects were recruited from K university hospital over 8 months. The data were analyzed by t-test, ANOVA, Pearson correlation and partial correlation analysis. Results: 1) Subjects perceived with moderately high uncertainty(M=65.98); moderate physical health(M=39.80), mental health(M=47.38), and general health(M=2.94); moderate anxiety(M= 44.78); and slightly low depression(M=15.33). 2) There were significant differences in uncertainty by gender and education. 3) Uncertainty and danger appraisal were significantly correlated(r=.32, p=.03) while the uncertainty was not associated with opportunity appraisal. 4) Uncertainty was significantly correlated with mental health(r=-.31, p=.04), anxiety(r=.38, p=.01), and depression(r=.37, p=.01). Conclusion: This study was the first trial to explore uncertainty and to examine the relationships among its associated factors in Korean patients with atrial fibrillation. Thus, based on the findings of this study, directions for nursing practice and further nursing research for patients with atrial fibrillation were suggested.

• Honam Mathematical Journal
• /
• v.31 no.4
• /
• pp.497-504
• /
• 2009

We introduce the concepts of M-preclosed graph and M$^*$-preopen mapping on spaces with minimal structures and investigate some properties of M$^*$-preopen mapping. We also investigate the relationships between M-precontinuous mappings and several types of m-compactness.

• Molecules and Cells
• /
• v.25 no.4
• /
• pp.510-522
• /
• 2008

To construct the molecular systematics of the genus Megoura (Hemiptera: Aphididae), DNA based-identification was performed using four mitochondrial and three nuclear DNA regions: partial cytochrome c oxidase I (COI), partial tRNA-leucine + cytochrome c oxidase II (tRNA/COII), cytochrome b (CytB), partial 12S rRNA + tRNA-valine + 16S rRNA (12S/16S), elongation factor-1 alpha ($EF1{\alpha}$), and the internal transcribed spacers 1 and 2 (ITS1, ITS2). Pairwise sequence divergences between taxa were compared, and phylogenetic analyses were performed based on each DNA region separately, and the combined datasets. COI, CytB, $EF1{\alpha}$, ITS1, and ITS2 were relatively effective in determining species and resolving their relationships. By contrast, the sequences of tRNA/COII and 12S/16S were not able to separate the closely related species. CytB and $EF1{\alpha}$ gave better resolution with higher average sequence divergences (4.7% for CytB, 5.2% for $EF1{\alpha}$). The sequence divergence of COI (3.0%) was moderate, and those of the two ITS regions (1.8% for ITS1, 2.0% for ITS2) were very low. Phylogenetic trees were constructed by minimum evolution, maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses. The results indicated that the phylogenetic relationships between Megoura species were associated with their host preferences. Megoura brevipilosa and M. lespedezae living on Lespedeza were closely related, and M. nigra, monophagous on Vicia venosa, was rather different from M. crassicauda, M. litoralis, and M. viciae, which are oligophagous on Lathyrus and Vicia. The three populations of M. crassicauda formed a clade separated from M. litoralis and M. viciae. Nevertheless M. litoralis and M. viciae, which are morphologically similar, were not separated due to negligible sequence divergence. We discuss the phylogenetic relationships of the Megoura, and the usefulness of the seven DNA regions for determining the species level phylogeny of aphids.

• Journal of the Chungcheong Mathematical Society
• /
• v.20 no.4
• /
• pp.569-575
• /
• 2007

Let M be a nonzero module. M has the property that every submodule of M lies over a direct summand of M. We study some properties of such a module. The endomorphism ring of such a module is also studied. The relationships of such a module to the semi-regular modules, and to the semi-perfect modules are described.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.9 no.2
• /
• pp.133-136
• /
• 2009

In this paper, we introduce the concept of IVF weakly $m^*$-continuous mappings on between IVF minimal spaces and investigate some characterizations for such mappings. Also we study the relationships IVF weakly $m^*$-continuous mappings and IVF M-compactness.

• Research in Mathematical Education
• /
• v.18 no.2
• /
• pp.129-148
• /
• 2014

In this study, we examined the relationships among years of teaching experience, professional rank, number of courses taken, and knowledge of algebra for teaching (KAT). 338 in-service and 376 pre-service secondary mathematics teachers in China completed a KAT questionnaire. Various statistical techniques were employed to examine these relationships. The pre-service participants teachers performed statistically significantly higher in advanced mathematics knowledge than their in-service counterparts. Among the inservice teachers, senior teachers had scored higher in school mathematics and teaching mathematics, compared with junior teachers. Yet participants' advanced mathematics knowledge decreased as their professional rank advanced or their teaching experience increased. The number of courses taken has significantly positive correlation with school mathematics knowledge and advanced mathematics knowledge. The implications of these findings for mathematics teacher education are discussed.