• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.471-476
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• 2004

We propose an analytical model to estimate the influence of a merger on the thermal SZ effect. Following observations we distinguish between subsonic and transonic mergers. Using analytical velocity fields and the Bernoulli equation we calculate the excess pressure around a moving subcluster for an incompressible subsonic gas. Positive excess around the stagnation point and negative excess on the side of the subcluster lead to characteristic signatures in the SZ map, of the order of $10\%$ compared to the unperturbed signal. For a transonic merger we calculate the change in the thermal spectral SZ function, resulting from bow shock accelerated electrons. The merger shock compression factor determines the power law tail of the new non-thermal electron population and is directly related to a shift in the crossover frequency. This shift is typically a few percent towards higher frequencies.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.690-692
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• 2001

A FEM model of the remote-field eddy current effect is presented for zirconium-2.5percent niobium(Zr-2.5%Nb) nuclear reactor pressure tubes to demonstrate the important electromagnetic field. Phenomena that describe this effect. This model is applied to evaluate the optimal operating frequency and detector position. There are many ambiguous experimental results connected with this technique. Finite element calculations can be used in the interpretation of these experimental results even though the electromagnetic fields measured in the remote-field technique are very small.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.7 no.3
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• pp.151-159
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• 1978

A heat transfer model for the case of simultaneous vibration of both the heated surface and its surrounding medium is constructed and the dimensional analysis is applied to this model in order to and the governing dimensionless Parameters in which the vibration effects the heat transfer. In the second Part of this study, an experimental investigation of the effect of vibration on natural convective heal transfer from spheres has been performed for the case of the external oscillatory motion being imposed on the heated surface which is immersed in an otherwise undisturbed air, The ranges of the experimental variables were: temperature difference 10 to $120^{\circ}C$; vibration frequency 10 to 120Hz; displacement amplitude 1.3 to 12.5mm. Three different diameter aluminum were used as the experimental models. Improvements in heat transfer due to vibration were observed, with the maximum increase being 330 Percent. A dimensionless correlation describing the measured heat transfer data is given.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.25-31
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• 2020

Boiling Liquid Expanding Vapor Explosion(BLEVE) can cause not only economic damage to the plant but also serious casualties. LPG accidents account for 89.6 percent of all accidents caused by gas leaks in Korea over the past nine years, while casualties from accidents also account for 73 percent of all accidents, according to statistics from the Korea Gas Safety Corporation. In addition, a potential explosion and a fire accident from one LPG storage tank may affect the nearby storage tanks, causing secondary and tertiary damage (domino effect). The safety distance standards for LPG used by LPG workplaces, charging stations, and homes in Korea have become stricter following the explosion of LPG charging stations in Bucheon. The safety distance regulation is divided into regulations based on the distance damage and the risk including frequency. This study suggests two approaches to optimizing the safety distance based on the just consequence and risk including frequencies. Using the Phast 7.2 Risk Assessment software by DNV GL, the explosion overpressure and heat radiation were derived according to the distance caused by BLEVE in the worst-case scenario, and accident and damage probability were derived by considering the probit function and domino effect. In addition, the safety distance between LPG tanks or LPG charging stations was derived to minimize damage effects by utilizing these measures.

• Steel and Composite Structures
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• v.25 no.2
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• pp.141-155
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• 2017

This paper presents an investigation into the magneto-thermo-mechanical vibration and damping of a viscoelastic functionally graded-carbon nanotubes (FG-CNTs)-reinforced curved microbeam based on Timoshenko beam and strain gradient theories. The structure is surrounded by a viscoelastic medium which is simulated with spring, damper and shear elements. The effective temperature-dependent material properties of the CNTs-reinforced composite beam are obtained using the extended rule of mixture. The structure is assumed to be subjected to a longitudinal magnetic field. The governing equations of motion are derived using Hamilton's principle and solved by employing differential quadrature method (DQM). The effect of various parameter like volume percent and distribution type of CNTs, temperature change, magnetic field, boundary conditions, material length scale parameter, central angle, viscoelastic medium and structural damping on the vibration and damping behaviors of the nanocomposite curved microbeam is examined. The results show that with increasing volume percent of CNTs and considering magnetic field, material length scale parameter and viscoelastic medium, the frequency of the system increases and critically damped situation occurs at higher values of damper constant. In addition, the structure with FGX distribution type of CNTs has the highest stiffness. It is also observed that increasing temperature, structural damping and central angle of curved microbeam decreases the frequency of the system.

• Korean journal of food and cookery science
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• v.28 no.1
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• pp.57-66
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• 2012

This study was carried out to investigate the effect of nutritional knowledge on food habits of male employees in Korea. A questionnaire was developed and distributed to 265 male employees of Seoul and Kyunggi area in Korea. The data were analyzed by t-test and ANOVA using SPSS (ver 12.0). Regarding the general aspects of subjects, the highest percent of ages were between the age 21-30 year old. Most respondents were graduates from a university. About twenty percent of male employees' average income was 1-2 million won per month. Most of their families were nuclear families. Eighty three percent of the respondents did not experience any education on nutrition and obtained food and nutritional information from television and internet. The respondents had a high level of perceived knowledge (86.2%); yet, the accuracy of knowledge was lower than the perceived knowledge (72.31%). Regarding the nutritional knowledge, single groups showed a lower score than married groups and groups living with family. Higher nutritional knowledge correlated with higher educational levels, among man in their twenties and thirties. With regards to their eating habits, the frequency of food intake within a weekly period was significantly different; a large percentage of respondents had high frequencies of instant food, alcohol consumption, and smoking. The higher scores regarding dietary habits were for age groups ranging from 41-60 year old, married individuals, nuclear family groups and educational groups with university degrees. Based on the results of this study, male employees have problem concerning food habits in that they are unbalanced and have a tendency to skip meals. Therefore, for the improvement of nutritional status and eating behavior of male employees, the importance of nutrition needs to be emphasized with proper nutritional education programs.

• Quality Improvement in Health Care
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• v.22 no.2
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• pp.75-90
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• 2016

Objectives: This study measures the level of cognition of employee's patient safety culture and evaluates the current level through comparing the results to external levels. Ultimately it is performed to construct a strategic improvement plan through the basic database for patient's safety culture. Methods: A questionnaire survey of self reporting type was carried out using structured questionnaire of the patient's safety culture for employees currently employed in a hospital. Total responders was 1,129 and a response rate was 54.6%. The survey results were calculated with a percent positive response, and the current level was evaluated by comparing with the survey results of a hospital (2009 and 2014) and the survey result of The Agency for Healthcare Research and Quality(2014). Results: Sub-dimension of high percent positive response for each area were 'teamwork within hospital units' (80%), 'feedback & communication about error' (73%) and 'supervisor/manager expectations & actions promoting safety' (67%). Meanwhile, 'teamwork across hospital units' (31%), 'hospital management support for patient safety' (29%), 'staffing' (27%) and 'non-punitive response to error' (17%) were relatively low percent positive response. Compared to the survey results of AHRQ (2014) for each area, 'teamwork within hospital units' (80%), 'feedback & communication about error' (73%), 'frequency of event reporting' (66%) were at the top 50% percentile level and the remaining sub-dimensions showed a very low level in the lower 10% percentile area. Conclusion: In order to establish a system for patient safety culture within the hospital and evaluate the effect on this, it is necessary to periodically evaluate the patient's safety culture and establish regulations on hospital safety culture to comply with this.

• Journal of the Korean Society of Food Culture
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• v.13 no.5
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• pp.487-496
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• 1998

The survey was conducted in July first to 15th, among 463 elementary school students, 4th grade to 6th grade in Chonj. The subjects were 252 male and 211 female students. The mean age of the subjects was 9.8 year The percent of relative body weight of the subjects compared to Korean standard was 100.1%, it almost matched to Korean standard. The percent of relative body weight in male students was 100.4%, where as the female's was 99.7%. Thirty six percent of the subjects have breakfast irregularly. The reason skipping breakfast were 'no appetite' 50.5%, 'get up late' 35.8%,' no delicious food' 18.2%. The reason skipping breakfast was significantly different by sex and obese index. The frequency taking snack was significantly different by sex, 34.6% of female subjects took snack more than twice per day, while 16.7% of male subjects did it. The most frequently taking snack were fruits, the points was 4.0 of 5.0. Ramyun, Sundai were taking more frequently among males than females. Females took fruits more frequently than males. Hot dog, ice cream ,and chocolate intakes were significantly different by obese index. The most preference of snack were fruits and ice cream in all subjects. The preference of ramyun, hamburger, egg, chicken, dried squid, milk, peanut, and soft drink were higher in males than in females. Biscuit, ice cream, and chocolate preference were significantly different in obese index.

• Korean Journal of Psychosomatic Medicine
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• v.5 no.1
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• pp.52-62
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• 1997

This study was designed to determine the frequency of premenstrual dysphoric disorder in gynecological outpatients, and also attempted to compare premenstrual change characteristics, functional impairment due to premenstrual changes and frequency of risk factors reported by women with confirmed premenstrual changes$(PMC^+)$(n=17) and those without confirmed premenstrual changes$(PMC^-)$(n=23). Forty gynecological outpatients who complained of premenstrual discomforts were asked to complete questionnaires on menstrual history, obstetric-gynecological history, and premenstrual change and functional impairment. The women were also asked to complete a daily rating form based on DSM-IV diagnostic criteria for one menstrual cycle. Absolute severity method, effect size method and percent change method were used to assess changes between follicular phase and luteal phase. The results of the study were as follows: 1) The frequency of premenstrual dysphoric disorder according to each of the three methods was 5% for the absolute severity method, 15% for the effect size method, and 27.5% for the percent change method. 2) The frequently reported symptoms were as follow: physical symptoms(64.7%) : lethargy, easy fatigability, or marked lack of energy(41.2%) : decreased interest in usual activities(29.4%) ; and marked affective lability(23.5%). 3) There were no significant differences in onset ages of premenstrual changes, regularities of premenstrual changes and changes of severity and duration of premenstrual symptoms over time between women with and without confirmed premenstrual changes. However, women with confirmed premenstrual changes reported both physical and emotional symptoms as earliest symptoms most frequently, while women without confirmed premenstrual changes reported only physical symptoms most frequently. 4) functional impairment was significantly higher in women with confirmed premenstrual changes than those without confirmed premenstrual changes, but impairment was not severe. 5) No differences were found between women with and without confirmed premenstrual changes in risk factors including demographic data, menstrual and obstetric and gynecological history. These results suggest that the prevalence of premenstrual dysphoric disorder varies with scoring methods. The women with confirmed premenstrual changes reported physical symptoms most frequently(64.7%). functional impairment was significantly higher in women with confirmed premenstrual changes, but impairment was not severe.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.52-58
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• 2005

The assessment on characteristics of hydraulic behavior and water quality variations of underground reservoirs of buildings were studied. Firstly, it was thought that underground reservoir capacities($m^3$) of buildings should be not determinated by the uniform and same methods but be estimated on the basis of the dwelling areas on dominated households and their residential characteristics, because these characteristics influence significantly on actual water usages and patterns of buildings. Secondly, it was likely that the average reduction rate of residual chlorine in underground reservoirs were affected from the their capacities, because the average reduction rate of residual chlorine in underground reservoirs under $1,000m^3$ was 43 percent, on the other hand, that rate of underground reservoirs over $1,000m^3$ was 60 percent. Thirdly, through the field investigation, the retention time of drinking water in underground reservoirs were in the range from 0.3 day to 3.9 day. In addition to, the average reduction rate of residual chlorine were depended largely on the retention time of drinking water. When the retention time was under 24 hours, the average reduction rate of residual chlorine was 45 percent, and in case of over 24 hours, was 49 percent. Fourth, water level in underground reservoirs was averagely varied in the range from 0.1 m to 2.65 m at the height of underground reservoirs. If considered actual height of underground reservoirs, 37.6 percent of the height of underground reservoirs was only used. Consequently, the frequency of the inflow and outflow of drinking water in underground reservoir were very increased, and had an effect on the reduction of residual chlorine. Lastly, the investigations on hydraulic structure characteristics of underground reservoirs inside showed the locations of inflow and outflow of drinking water almost were in the opposite direction. And some buildings had several baffles in the middle. Nevertheless, their installations had no beneficial for the improvement of water quality.