• Journal of the Korean Institute of Gas
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• v.11 no.3
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• pp.1-6
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• 2007

The heat transfer coefficient and pressure drop during gas cooling process of $CO_2$ (R-744) in inclined helical coil copper tubes were investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube, which is specified as the inner diameter of 4.55 mm. The refrigerant mass fluxes were varied from 200 to $600kg/m^2s$ and the inlet pressures of gas cooler were done 7.5 to 10.0 (MPa). The heat transfer coefficients of $CO_2$ in the inclined helical coil tubes increase with the increase of mass flux and gas cooling pressure of $CO_2$. The pressure drop of $CO_2$ in the gas cooler shows relatively good coincidence with those predicted by Ito's correlation developed for single-phase in a helical coil tube. The local heat transfer coefficient of $CO_2$ is well coincident with the correlation by Pitla et al. However, at the region near pseudo-critical temperature, the experiments indicate higher values than the Pitla et al. correlation.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.132-143
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• 2019

The purposes of this study are to identify how university's entrance examination system is related to private education, and to explore how to improve the university of education entrance system in order to reduce private education costs. For these purposes, 116 teachers of senior students in high school in Daegu and Gyeongbuk and 107 pre-service teachers who had experienced the entrance of the university were surveyed in order to find out the perception of the relationship between admissions elements and private education. As a result, it is possible to concentrate more on school education by strengthening high school grades in the entrance examination. However, there was other opinion that the strengthening high school grades in the university entrance could lead to the further increase in the cost of private education. As there are big differences in the perception of the screening factors between rural areas (Gyeongsangbuk-do) and large cities (Daegu), it is necessary to introduce the entrance examination system considering the characteristics of each region. Third-year teachers in high schools argued that university admissions should reduce the rate of the College Scholastic Ability Test (CSAT) and increase the rate of interviews. The results of this study suggest that the improvement of the university entrance examination system to reduce the cost of private tutoring requires securing fairness of document evaluation, strengthening interviews, and opening interview questions.

• Journal of the Korean Chemical Society
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• v.67 no.5
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• pp.378-392
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• 2023

The purpose of this study is to analyze the pre-service chemistry teachers' cognition of the nature of model in process of designing and developing models using technology. For this purpose, 19 pre-service chemistry teachers' in the 3rd grade of a education college located in the central region observe experimental phenomena related to Boyle's law presented in the 7th grade science textbook and researchers required the design and development of a model related to the observed experimental results using technology. Based on previous studies, the nature of model were classified into two aspect: 'Representational aspect' and 'Explanatory aspect'. The 'Representational aspect' was classified into 'Representation', 'Abstraction', and 'Simplification', and the 'Explanatory aspect' was classified into 'Analysis', 'Interpretation', 'Reasoning', 'Explanation', and 'Quantification'. The pre-service chemistry teachers' cognition were analyzed by the classification. As a result of the study, the 'Representation' of the 'expressive aspect' was uniformized in the form of space that changes in volume, and the pressure was expressed as the Brightness inside the cylinder or frequency of color change of particles for 'Abstraction'. In the case of 'Simplification', the particle collision was expressed as a perfectly elastic collision, but there was a group that could not simply indicate the type of particle. In the 'Explanatory aspect', in the case of 'Analysis', volume was classified as a manipulated variable, and in the case of 'Interpretation', most groups analyzed the change in pressure through the collision of gas particles. However, the cognition involved in 'Reasoning' was not observed much. In the case of 'Explanation', there were groups that did not succeed in explanation because the area where the particles collided was not set or incorrectly set, and in the case of 'Quantification', there was a group that formulated the number of collisions per unit time, and on the contrary, there was a group that could not quantify the number of collisions because they could not be expressed in numbers.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.239-246
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• 2008

Yeongweol sericite deposit of Gangwon Province is regarded as one of the sericite deposits derived from granitic rocks due to post-magmatic alkali metasomatism, and the other sericite deposit of the same origin is the Daehyun mine of Gyungbug Province. Sericite ores were originated from leucocratic granitic stocks of Cambrian-Triassic age which intruded the pegmatitic migmatite of the unknown age and granite of the Pre-cambrian age, respectivcly. Jangsan quartzite of the lowermost formations of the Paleozoic era, which played as the capping rock protected from the leakage of the hydrothermal solution. It is well known that those sericite deposits arc formed during formation of the geosyncline, and they are also situated in the margins of the Hambaeg Syncline. Leucocratic granites commonly contain pegmatites with tourmaline crystals, and are rich in potassium feldspars, and sodium plagioclase as well. Sericitized ores are mainly found as we go up to the higher elevations or to the margins of the stocks. And some of the Highest grade sericite ores show the monominerallic character composed of nearly pure sericite probably doc to the ultra greisenization. Chemical analysis shows higher $Na_{2}O$ and $K_{2}O$ contents $(2.00\sim7.03wt%)$ as the sericitizations arc preceded and they represent obvious greisenization. But low CaO contents $(0.05\sim4.51wt%)$ indicate that albitizations are so weak. Pyrophyllite of the Youngweol area is often accompanied by the sericite, indicating rather stronger thermal effect than the Daehyun mine. It is known that there are several Sn deposits originated from greisenization in the Taebaegsan region. And greisens are inclined to contain W, Mo and several REE's such as Be, Nb and Li, and so Taebaegsan region interbedded with lots of carbonate formations are still worthwhile to survey for those metallic deposits.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.264-274
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• 2020

Background: Climate change has altered the various ecosystem processes including forest ecosystem in Himalayan region. Although the high mountain natural forests including treelines in the Himalayan region are mainly reported to be temperature sensitive, the temperature-related water stress in an important growth-limiting factor for middle elevation mountains. And there are very few evidences on growth performance of planted forest in changing climate in the Himalayan region. A dendrochronological study was carried out to verify and record the impact of warming temperature tree growth by using the tree cores of Pinus roxburghii from Batase village of Dhulikhel in Central Nepal with sub-tropical climatic zone. For this total, 29 tree cores from 25 trees of P. roxburghii were measured and analyzed. Result: A 44-year long tree ring width chronology was constructed from the cores. The result showed that the radial growth of P. roxburghii was positively correlated with pre-monsoon (April) rainfall, although the correlation was not significant and negatively correlated with summer rainfall. The strongest negative correlation was found between radial growth and rainfall of June followed by the rainfall of January. Also, the radial growth showed significant positive correlation with that previous year August mean temperature and maximum temperature, and significant negative correlation between radial growth and maximum temperature (Tmax) of May and of spring season (March-May), indicating moisture as the key factor for radial growth. Despite the overall positive trend in the basal area increment (BAI), we have found the abrupt decline between 1995 and 2005 AD. Conclusion: The results indicated that chir pine planted population was moisture sensitive, and the negative impact of higher temperature during early growth season (March-May) was clearly seen on the radial growth. We emphasize that the forest would experience further moisture stress if the trend of warming temperatures continues. The unusual decreasing BAI trend might be associated with forest management processes including resin collection and other disturbances. Our results showed that the planted pine forest stand is sub-healthy due to major human intervention at times. Further exploration of growth climate response from different climatic zones and management regimes is important to improve our understanding on the growth performance of mid-hill pine forests in Nepal.

• Research in Community and Public Health Nursing
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• v.13 no.2
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• pp.280-291
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• 2002

Objectives: This study was conducted to evaluate the maternal child health services provided by public health centers in Pyungtaek city. Methods: Data were collected based on multiple sources of official records. A questionnaire survey was obtained from 50 mothers with premature babies, and 89 mothers with full- term babies, in order to compare their demographic factors, and physical, obstetrical, and emotional status. In addition, the investigators collected data on pre and post follow-up care for the remature group to evaluate the effects of home visiting services on them. Moreover, additional data were collected from 135 pregnant women and 315 mothers with infants, to assess their degree of satisfaction for prenatal education course and breast feeding practices. Results: 1) The pregnant women's satisfaction for the prenatal education course, knowledge, and practices on self care were considered to be high. 2) Of the mothers with infants, 62.9% experienced breast feeding, but only 35.9% of them did it for six months. 3) Premature birth rate in the region was 5.6%, and 75.6% of all premature babies received follow-up care. 4) The mothers with premature babies experienced premature rupture of membrane. placenta previa, preeclampsia, and cesarean section more frequently than the mothers with full-term babies. 5) At the pre-intervention data collection point. mothers with premature babies experienced significantly less social support than mothers with full-term babies. In addition, mothers with premature babies reported higher levels of stress and care-giving burdens, and lower level of self esteem, than mothers with full-term babies, although the differences were not statistically significant. 6) In the premature group, stress, care giving burdens, and postpartum depression decreased after the intervention, whereas maternal self esteem, and the husband's support were increased after the intervention. Social support from significant others were somewhat decreased. 7) Satisfaction for the home visiting service in the mothers with premature babies was very high. Conclusion: These results showed a possibility that the recently started maternal child health services provided by the public health centers may be efficient. Although statistically significant differences were not found, the investigators found a potential for changes in a positive direction. Long-term effects of the health services on maternal child health needs should be addressed in future studies.

• Journal of agricultural medicine and community health
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• v.47 no.4
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• pp.220-228
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• 2022

Objective: glucometer is one of POCT(point-of-care testing) devices used by EMS. Accurate measurement value is important for patient decision making. Quality control is necessary for this, but most EMS are still using glucometer without quality control it. Therefore, management status and quality control status of glucometers used by 119 paramedics waswere investigated. Methods: 6 and 8 of glucometers and blood glucose test strips were submitted from 4 safety centers in 2010 and 8 safety centers in 2012, respectively. Glucometers submitted by local safety centers were analyzed in 2010 and 2012. The control glucometer, which was well managed at A University Hospital, was assumed to be accurate for at blood glucose measurement. Glucose values of various quality control materials control solutions were measured and analyzed using linear regression and Pearson's correlation test. Error rates were obtained via error tolerance range required by the 2011 ISO(International Organization for Standardization) guideline. For statistics, Excel and MedCalC programs were used. Results: mong 14 safety centers in the region, 4 centers(28.5%) in 2010 and 8 centers(57.1%) in 2012 submitted 6 and 8 glucometers. In the first evaluation in 2010, 2 out of 6(33.3%) glucometers were untestable due to error, and 45 out of 6(66.683.3%) blood glucose test strips' validity were expired. In the second evaluation in 2012, 1 out of 8(13.5%) glucometers were untestable due to lack of battery, and 2 out of 8(25%) blood glucose test strips' validity were expired. All correlation coefficients were above 0.989 in 2010 and above 0.997 in 2012. Error rates were generally high when using expired blood glucose test strips. Conclusion: Among 119 paramedics' guideline, quantity and operation status of POCT devices are well managed, but quality control is not. Therefore, it is necessary to add management status and quality control status of POCT devices to the EMS' field work guideline.

• The korean journal of orthodontics
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• v.46 no.2
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• pp.96-103
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• 2016

Objective: To compare the transverse dental changes induced by the palatally applied Frog appliance and buccally applied Karad's integrated distalizing system (KIDS). Methods: We evaluated the pre- and post distalization orthodontic models of 39 patients, including 19 treated using the Frog appliance, which is palatally positioned (Frog group), and 20 treated using KIDS, which is buccally positioned (KIDS group). Changes in intermolar and interpremolar distances and the amount of maxillary premolar and molar rotation were evaluated on model photocopies. Wilcoxon and Mann-Whitney U tests were used for statistical evaluations. A p-value of < 0.05 was considered statistically significant. Results: Significant distopalatal rotation of premolars and distobuccal rotation of molars were observed in Frog group (p < 0.05), while significant distopalatal rotation of molars (p < 0.05), with no significant changes in premolars, was observed in KIDS group. The amount of second premolar and first molar rotation was significantly different between the two groups (p < 0.05 and p < 0.001, respectively). Furthermore, expansion in the region of the first molars and second premolars was significantly greater in KIDS group than in Frog group (p < 0.001 for both). Conclusions: Our results suggest that the type and amount of first molar rotation and expansion vary with the design of the distalization appliance used.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.3
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• pp.263-271
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• 2007

The heat transfer coefficient and pressure drop during 9as cooling process of $CO_2$ (R744) in a helically coiled copper tube with the inner diameter of 4.55 mm and outer diameter of 6.35 mm were investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump. a mass flow meter a pre-heater and a helically coiled type gas cooler (test section). The refrigerant mass fluxes are varied from 200 to $800kg/m^2s$ and the inlet pressures of gas cooler are 7.5 to 10.0 MPa. The heat transfer coefficients of $CO_2$ in a helically coiled tube are higher than those in a horizontal tube. The Pressure drop of $CO_2$ in the gas cooler shows a relatively good agreement with those predicted by Ito's correlation developed for single-phase in a helically coiled tube. The local heat transfer coefficient of $CO_2$ agrees well with the correlation by Pitla et al. However. at the region near pseudo-critical temperature. the experiments indicate higher values than the Pitla et al correlation. Therefore, various experiments in helically coiled tubes have to be conducted and it is necessary to develop the reliable and accurate prediction determining the heat transfer and pressure drop of $CO_2$ in a helically coiled tube.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.981-986
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• 2010

Genetic parameters of growth traits were estimated in the German Angora rabbit reared in the sub-temperate region of India. Estimates of (co)variance components were obtained for body weights at weaning (42 days) and post-weaning at 84, 126 and 168 days. A total of 8,324 animal records were used for the analysis of these traits. The data were analyzed by restricted maximum likelihood (REML) fitting six animal models with various combinations of direct and maternal effects. A log likelihood ratio test was used to select the most appropriate univariate model for each trait. Direct heritability estimates were observed to be moderate for the traits under study. Heritability estimates for weaning (42 d), 84, 126 and 168 d weights obtained from the best models were $0.25{\pm}0.05$, $0.17{\pm}0.05$, $0.21{\pm}0.06$ and $0.12{\pm}0.05$. Maternal effects had higher importance at weaning, and declined with the advancement of age. Significant maternal permanent environmental effect on weaning and post-weaning weights was a carryover effect of maternal influences during pre-weaning age. The estimated repeatabilities of doe effects on body weights were 0.37, 0.22, 0.18 and 0.28 at weaning, 84, 126 and 168 d body weight, respectively. Results indicated that modest rate of genetic progress is possible for body weight traits of Angora rabbit through selection. Similarly, these growth traits could be included in selection criteria along with wool traits for early selection of the animals.