• Economic and Environmental Geology
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• v.25 no.3
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• pp.233-243
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• 1992

Ore mineralization of the Hwanghak copper deposit in the Ogsan area occurred in three stages of quartz (stage I and II) and calcite (stage III) veining along fissures in Early Cretaceous sedimentary rocks. Ore minerals are pyrite, pyrrhotite, chalcopyrite (dominant), sphalerite, hematite, galena, and Ag-, Pb-, and Bi-sulfosalts. These were deposited during the first stage at temperatures between $370^{\circ}C$ and < $200^{\circ}C$ from fluids with salinities between 0.5 and 7.6 equiv. wt. % NaCl. There is evidence of boiling and this suggests pressures of less than 180 bars during the first stage. Equilibrium thermodynamic interpretation accompanying with mineral paragenesis and fluid inclusion data indicates that copper precipitation in the hydrothermal system occurred due to cooling and changing in chemical conditions ($fs_2$, $fo_2$, pH). Gradual temperature decrease from $350^{\circ}$ to $250^{\circ}C$ of ore fluids by boiling and mixing with less-evolved meteoric waters mainly led to copper deposition through destabilization of copper chloride complexes. Sulfur isotope values of sulfide minerals decrease systematically with paragenetic time from calculated ${\delta}^{34}S_{H_2S}$ values of 8.2 to 4.7‰. These values, together with the observed change from sulfide-only to sulfide-hematite assemblages and fluid inclusion data, suggest progressively more oxidizing conditions, with a corresponding increase of the $sulfate/H_2S$ ratio of hydrothermal fluids. Measured and calculated hydrogen and oxygen isotope valutls of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values.

• Journal of The Korean Association For Science Education
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• v.19 no.1
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• pp.1-7
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• 1999

The purpose of this study was to survey the high school students' concern levels on decision-making problems based on biology, This study is a exploratory research to develop teaching strategies and curriculum of the common science for the enhancement of the students' decision-making ability in problems involved biological knowledges. The survey subjects were 101 first graders of the high school in Seoul area. The survey instrument developed was 5-point scale of Likert type consisted of 24 question items. The survey results showed that the concern level on selection of method for learning was the highest. The concern levels on selection of method for sports or diet which are the individual faced problems were high, and concern levels on the problems social issued such as decisions about standard for noise, pros and cons of approval for brain death or artificial abortion were high, too. The students' concern levels on problems individual context were significantly higher than concern levels on problems social context (p<0.01). The males' concern levels were higher than females' on 'AIDS', 'incinerator for rubbish', 'atomic power plant', 'protection policy for decreasing species', 'standard for noise' (p<0.05), And the males' concern levels were higher than females' on domain of 'ecosystem and environment pollution'. But the females had higher concern levels than males on 'diet' and 'surrogate mother' (p<0.05). The analyzed results were discussed in respects of implication for teaching strategies and curriculum.

• Applied Microscopy
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• v.32 no.2
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• pp.107-119
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• 2002

Early spermatocytes of U. unicinctus are found in cluster floating in the coelomic fluid. The spermatocytes in a cluster form a syncytium or cytoplasmic mass, but there are no indications that the cytoplasmic mass is a component of a somatic cell. This work suggested that this type of spermatogenesis can be subordinated to solitary spermatogenesis in the sense excluding structural and functional support of a somatic cell for sperm developments. The solitary spermatogenesis in U. unicinctus is different in appearances and developmental details of sperm organelles and stage distributions from that of localized spermatogenesis. The acrosomal rudiments and centrioles can be observed in the early single cells of spermatogonia and clearly disclosed in the primary spermatocyte. In the stage of secondary spermatocyte, the acrosomal precursor and the centrioles begin to move to each cytoplasmic poles. The polarities of the organelles are attained at stage of spermatids. The spermatocytes and spermatids are arranged circumferentially along the cytoplasmic mass in which some amorphological cytoplasmic components are included. The spermatids reveal to be detached from the cytoplasmic mass into coelomic fluid. It suggests that the spermatogenesis are progressed in support of coelomic fluid, and the fact take into consideration that the spermatogenic cells can be in vitro cultured without somatic cells and with supplements of coelomic fluid.

• Korea journal of population studies
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• v.21 no.2
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• pp.58-82
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• 1998

It is usually proposed that job security of old age workers is hampered by the structure of wage increasing with age. This paper sets forth a model to comprehend the characteristic of the old age workers' labor market and policy implications derived from it. In order to stimulate demand for old age workers, policy initiatives should be taken as follows : the wage criteria should be simplified which apply differently from one institution to other; incentives relatively favorable for employing old age workers' in manufacturing sector should be also given to service sectors; employment subsidy or other tax incentives should be given for labor contract after the retirement age; licensing and evaluation system for job ability should be introduced based on occupation & job analysis. To lower the reservation wage of workers, mortgage loan for house and long-term low interest loan for tuition fees should be developed together with stabilization of housing cost. Wedding culture which requires high expense should be amended. Above all, it is necessary to install reasonable social security system. Policy orientation should also pay attention to reduce labor supply of the old aged via aiding old age workers' firm opening and voluntary civil service together with developing various honor programs for members of civil corps.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.249-256
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• 2014

Advancing health screening and treatment of cancer techniques, they contribute to grow the probability of survival of cancer patients for a long time. So health behavior and quality of life of the patients are getting important. This study analysed correlation between healthy person and cancer patient's EQ-5D index, social demographic characteristics, health behavior and so on by the multiple regression analysis. The result was that EQ-5D index of cancer patients is lower than healthy persons. Patients of cervical cancer and lung cancer had very low the index especially. In conclusion, cancer have a bad influence on the quality of life. For cancer patients, smoking and drinking are a major factors of correlation. The number of non-smokers among the patients is lower than the number of smokers among healthy persons. This conclusion means that the importance of health behaviors and quality of life for cancer patients is established so that this will be used for basic reference of PHR models and service enhancing quality of life.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.9-18
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• 2016

The slender structures such as high rise building or marine riser are highly susceptible to dynamic force exerted by fluid-structure interactions among which vortex-induced vibration(VIV) is the main cause of dynamic unstability of the structural system. If VIV occurs in natural frequency regime of the structure, fatigue failure likely happens by so-called lock-in phenomenon. This study presents the numerical analysis of dynamic behavior of both structure and fluid in the lock-in regimes and investigates the subjacent phenomena to hold the resonance frequency in spite of the change of flow condition. Unsteady and laminar flow was considered for a two-dimensional circular cylinder which was assumed to move freely in 1 degree of freedom in the direction orthogonal to the uniform inflow. Fluid-structure interaction was implemented by solving both unsteady flow and dynamic motion of the structure sequentially in each time step where the fluid domain was remeshed considering the movement of the body. The results show reasonable agreements with previous studies and reveal characteristic features of the lock-in phenomena. Not only the lift force but also drag force are drastically increasing during the lock-in regime, the vertical displacement of the cylinder reaches up to 20% of the diameter of the cylinder. The correlation analysis between lift and vertical displacement clearly show the dramatic change of the phase difference from in-phase to out-of-phase when the cylinder experiences lock-in. From the results, it can be postulated that the change of phase difference and flow condition is responsible for the resonating behavior of the structure during lock-in.

• The Journal of the Petrological Society of Korea
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• v.20 no.2
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• pp.99-114
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• 2011

Precambrian gneiss complex in the Pyeongchang-Wonju area, which lies west of the Paleozoic sedimentary basin of the Yeongwol-Taebaek area, is being considered as a part of the Gyeonggi massif, but its ages of formation and metamorphic events are not well defined yet. In this study, SHRIMP zircon U-Pb ages were determined from the gneiss complex in the area, We obtained the discrete ages of magmatic (ca. 1960 Ma) and metamorphic (ca. 1860 Ma) events through the interpretation of the SHRIMP data based on the internal structures of zircons. These are almost the same to the ages of main intrusion and metamorphism reported from the Precambrian basements of Gyeonggi, Yeongnam and Nangnim massifs of the Korean Peninsula, Ages of 3200~3300 Ma, 2900 Ma, 2660 Ma, 2430 Ma, 2260 Ma, and 2080~2070 Ma obtained from inherited cores of studied zircons are also very similar to the frequently reported ages from the basement rocks of the Gyeonggi and Yeongnam massifs, Lower intercept age of about 270 Ma calculated from the rim data seems to indicate that the study area suffered from a late Paleozoic metamorphism (Okcheon Orogeny), but we need more reasonable and sufficient data to confirm it. According to the results of this study, it is suggested that the Bangnim group unconformably overlying the gneiss complex was deposited after the Paleoproterozoic granitic magmatism (ca. 1960 Ma) and metamorphism (ca. 1860 Ma).

• Journal of Dairy Science and Biotechnology
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• v.34 no.1
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• pp.37-41
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• 2016

Melatonin is a hormone produced by the pineal gland in dark conditions. It plays a major role in the regulation of the sleep-wake cycle. Melatonin synthesis is known to be suppressed by environmental light. Cortisol is a steroid hormone that is a major indicator of physiological alterations due to stressful stimuli. It also displays a circadian rhythm, like melatonin. The highest levels are encountered during early morning and the lowest levels are observed at around midnight. In the present study, the effects of milking time on the melatonin and cortisol concentrations of raw milk and milk powder at the summer and winter solstices were examined. The melatonin concentration in milk increased significantly if cows were milked in the dark at night (p<0.05). The melatonin concentration in milk powder showed the same pattern with respect to the milking time (p<0.05). However, no significant difference in the cortisol concentration was observed between day- and night-time milk. Although the time of day did not affect the level of milk cortisol, seasonal factors affected the release of cortisol in milk (p<0.05). In conclusion, night-time milk is rich in endogenous melatonin. In this respect, it has potential applications for the development of melatonin rich-dairy products, which serve as natural sources of melatonin.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.317-327
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• 2012

The purpose of present study was to observe the path and influencing effects between socioeconomic class (SEC), health practices and self-rated health(SRH) by the age bracket. The subjects were 4,987 adults over 25 years old who participated in the 2008 Korean National Examination Health and Nutrition Survey and could be classified into SEC in terms of the three characteristics: education, income and occupation. Path analysis was conducted with the effects of health behaviors execution on the differences in SRH, and the complex samples analysis executed by chi-square test, t-test, ANOVA. As the result, lower SRH level paralleled with the lower SEC, and more health behaviors had differed by SEC in the younger and middle aged group. The lower SEC, the lower SRH: non-smoking and weight control for younger women and exercise for aged men had indirect effects as parameters. In conclusion, when planning a health promotion program, to select the correct target populations with consideration of the age bracket, gender and SEC and to establish tailored contents fit for each of the population would be important.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.2
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• pp.73-77
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• 2008

Purpose: The purpose of this study was to describe the method of dynamic sonographic measurements in the evaluation of the MCL injury of the knee joint while applying valgus and varus stress. Materials and Methods: Seven cases of MCL injury from January to April of 2008 was used for the study. For the evaluation of the medial instability, sonography was used immediately after injury, 6 weeks and 12 weeks after conservative treatment with limited motion brace. The length between the foot of the medial femoral epicondyle and the most proximal point of the tibial cortex was measured in 30 degrees flexion with valgus and varus stress of the knee joint. Results: The foot of the medial epicondyle and the starting point of the proximal tibial cortex underneath the round portion of the articular cartilage were always able to be seen on ultrasonography, even in varus and valgus stress with gravity in 30 degrees flexion of the knee joint. The results of measurements were always constant. Conclusion: Sonography can be used in evaluation of medial instability under the dynamic valgus and varus stress of the knee joint without further injury.