• Korean Journal of Materials Research
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• v.20 no.3
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• pp.142-147
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• 2010

Nano-sized $BaNd_2Ti_5O_{14}$ powders were prepared by the spray pyrolysis process. Sucrose used as the organic additive enabled the formation of nano-sized $BaNd_2Ti_5O_{14}$ powders. The powders prepared from the spray solution without sucrose had a spherical shape, dense structure and micron size before and after calcination. However, the precursor powders prepared from the spray solution with sucrose had a large size, and hollow and porous morphology. The precursor powders had an amorphous crystal structure because of the short residence time of the powders inside the hot wall reactor. The complete decomposition of sucrose did not occur inside the hot wall reactor. Therefore, the precursor powders obtained from the spray solution with sucrose of 0.5M had a carbon content of 39.2wt.%. The powders obtained from the spray solution with sucrose of 0.5M had a slightly aggregated structure of nano-sized primary powders of $BaNd_2Ti_5O_{14}$ crystalline phase after calcination at $1000^{\circ}C$. The calcined powders turned into nano-sized $BaNd_2Ti_5O_{14}$ powders after milling. The mean size of the $BaNd_2Ti_5O_{14}$ powders was 125 nm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.6
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• pp.1983-1993
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• 1996

For selected (pure and compound) metallic species effects of saturation ratio, temperature, particle size and number density on condensation mechanisms are first reviewed. The tendencies for vaporization and condensation differ between metallic species because of the significant differences in their saturation pressures. Then particle pressure of a metal vapor species at incineration temperature is calculated by simplifying waste as a compound of methane, chlorine and small amounts of metals and assuming a thermodynamic equilibrium state. Next the condition is assessed for which supersaturation of combustion gases by the species above the critical level for homogeneous condensation may occur, when the gases contain a large number of pre-existing particles such as entrained ashes. Regardless of the presence of chlorine in the waste, the homogeneous condensation of PbO vapors may occur, depending on number density of the pre-existing particles. However, when chlorine exists in the waste, the homogeneous condensation of PbCl$_2$vapors does not occur, which is similar to the case of Cd and Hg vapors. Thus these highly volatile species, PbCl$_2$, Cd, and Hg, may emit to atmosphere as vapor phase. In general, for reducing the emission of hazardous metallic species into the atmosphere, the number density of pre-existing particles has to be increased. For fixed particle number density, the temperature drop rate must be kept in low if the temperature at which a condensable vapor species emits from a incineration system is fixed, while the temperature drop rate must be kept in high if the residence time for which a condensable species stays in the system is fixed.

• Nutrition Research and Practice
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• v.2 no.2
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• pp.107-113
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• 2008

This study was done to investigate the relationship between the perception of body image, body weight satisfaction or dietary behavior and self-rated health status in Korean college students. Subjects, 285 college students, were divided into three groups (healthy, normal, and unhealthy) according to the answer for the self-rated health question. Information about demographic status, self-rated health condition, height and weight, perception of body image, satisfaction of body weight, concern for body weight control, dietary behavior, nutritional knowledge, and health-related characteristics collected by a self-reported questionnaire. The proportion of men and women in each group was not significantly different. The academic year, major, experience of nutritional education, and type of residence were not significantly related with self-rated health but the pocket money range was significantly associated (p<0.05) with self-rated health. The proportion of subjects rated their health as unhealthy was the lowest in 210-300 thousand won pocket money range and was increased in less than 210 thousand won or over 300 thousand won pocket money ranges. There were no significant differences for age, height, weight and BMI between the groups. The body image perception and body weight satisfaction levels of healthy group was significantly higher than those of unhealthy group (p<0.01 and p<0.001, respectively), but the level of concern for body weigh1 control in healthy subjects was significantly lower than that in unhealthy subjects (p<0.05). The proportion of subjects reported as healthy was significantly increased with increased frequencies of following food behaviors; weekly use of protein foods (p<0.01), vegetables (p<0.05) and dairy products (p<0.01), and food habits such as "regularity of meal time" (p<0.01), "eating in moderation" (p<0.05), and "eating breakfast" (p<0.001). Overall results suggested that the college students have tended to have a better perception of health when they have better body image perception, body weight satisfaction and dietary behaviors.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.95-100
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• 2019

In this paper, autonomous vehicles of service with existing vehicle accident for the prevention of the vehicle communication technology, self-driving techniques, brakes automatic control technology, artificial intelligence technologies such as well and developed the vehicle accident this occur to death or has been techniques, can prepare various safety cases intended to minimize the injury. In this paper, it is a study to secure safety in autonomous vehicles. This is determined according to spatial factors such as chip signals for general low-power short-range wireless communication and micro road AI. On the other hand, in this paper, the safety of boarding is improved by checking the signal from the electronic chip, up to "recognition of the emotion from residence time in the sensing area" to the biological electronic chip. As a result of demonstrating the reliability of the world countries the world, inducing safety autonomous system of all passengers in terms of safety. Unmanned autonomous vehicle riding and commercialization will lead to AI systems and biochips (Verification), linked IoT on the road in the near future, and the safety technology reliability of the world will be highlighted.

• Journal of the Korea Society for Simulation
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• v.28 no.3
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• pp.25-40
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• 2019

Today, container terminals are fiercely competing to attract an increasing number of containers. As a way to improve terminal productivity, this study proposes two dispatching rules for yard truck allocation priorities. First, Multi-Attribute Dispatching Rule(MADR) is an allocation method to calculate the weighted sum of multiple factors affecting container terminal productivity and priority them. Especially, the workload of the quay crane was considered one of the factors to reduce the residence time of the ship. Second, Cycling Dispatching Rule(CDR) is the effective way to increase the number of double cycles that directly affect terminal productivity. To identify the effects of combinations of pooling and dispatching, a comparative experiments was performed on 8 scenarios that combined them. A simulation environment has been developed for experiments and the results have demonstrated that the combination of terminal level pooling and Multi-attribute Dispatching could be an excellent combination in KPIs consisting of GCR and delayed departure of ships, etc.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.78-86
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• 2000

The objective of this research is to understand the characteristics of a nonpremixed, turbulent, hydrogen jet flame which is stabilized in Mach 1.8 coflowing air flows. In order to investigate the flame structure, flame lengths and fuel trajectories were measured by using direct photography, acetone PLIF, Mie scattering techniques, and numerical simulation. Effect of increasing air velocity was investigated when fuel velocity is fixed. The subsonic flame length was decreased drastically, however the supersonic flame length was increased slowly Then the change of flame blow out characteristics was observed as varying fuel nozzle lip thickness. The flame stability can be increased when fuel nozzle lip thickness was increased, which indicates that the minimum fuel lip thickness ratio is required for the stable supersonic flames. Also, it is found that fuel jet is blocked by high pressure zone and low scattering zone is made. Then the fuel that was moving along the recirculation zone had longer residence time within the supersonic flames, which made partially premixed zone.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.853-860
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• 2019

In order to meet more severe environmental regulations, oxy-fuel circulating fluidized bed(CFB) boilers or ultra supercritical CFB boilers, which are a kind of process in that solid particles moves similar to fluid, have been developed in the world. In CFB power generation processes, the method to reduce or remove sulfur dioxide is in-situ desulfurization reaction via limestone directly injected into CFB boilers. However, the desulfurization efficiencies have continuously changed because limestones injected into CFB boilers are affected by various operation conditions (Bed temperature, pressure, solid circulating rate, solid holdup, residence time, and so on). In this study, a prediction method with physical and chemical properties of limestone and operation conditions of CFB boiler for in-situ desulfurization reaction in CFB boilers has developed by integrating desulfurization kinetic equations and hydrodynamics equations for CFB previously published. In particular, the prediction equation for in-situ desulfurization was modified by using experimental results from desulfurization reactions of various domestic limestones.

• Journal of Preventive Medicine and Public Health
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• v.54 no.4
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• pp.230-237
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• 2021

Objectives: This study explored changes in individuals' behavior in response to social distancing (SD) levels and the "no gatherings of more than 5 people" (NGM5) rule in Korea during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Using survey data from the COVID-19 Behavior Tracker, exploratory factor analysis extracted 3 preventive factors: maintenance of personal hygiene, avoiding going out, and avoiding meeting people. Each factor was used as a dependent variable. The chisquare test was used to compare differences in distributions between categorical variables, while binary logistic regression was performed to identify factors associated with high compliance with measures to prevent transmission. Results: In men, all 3 factors were significantly associated with lower compliance. Younger age groups were associated with lower compliance with maintenance of personal hygiene and avoiding meeting people. Employment status was significantly associated with avoiding going out and avoiding meeting people. Residence in the capital area was significantly associated with higher compliance with personal hygiene and avoiding venturing out. Increasing SD levels were associated with personal hygiene, avoiding going out, and avoiding meeting people. The NGM5 policy was not significantly associated with compliance. Conclusions: SD levels, gender, age, employment status, and region had explanatory power for compliance with non-pharmaceutical interventions (NPIs). Strengthening social campaigns to inspire voluntary compliance with NPIs, especially focused on men, younger people, full-time workers, and residents of the capital area is recommended. Simultaneously, efforts need to be made to segment SD measures into substrategies with detailed guidance at each level.

• Cross-Cultural Studies
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• v.26
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• pp.353-377
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• 2012

This treatise studies on how ideology and value of Chinese minority race undergo change according to social, political transition that the Chinese minority race has experienced for a long time and I also have tried to elucidate how these kinds of their experiences have been effected upon their own life, even it is part of my basic subjects for my study. Hence I would give weigh to focus on contemplating process of the past and the present rather than predictive discussion of how their pursuing value will be transformed. For my ebullient study, I'm willing to make Yi-Zu's moral culture become axis of my treatise, and capitalize on not only how Han-Zu's ideological philosopies have been disseminated, but also how acculturation have been taken place in Yi-Zu's moral culture system. Yi-Zu has the longest history and the greatest their own population, even the largest residence of various Chinese minority races. And Yun-Nan is the historical place where not only various Chinese minority races have lived, but also acculturation between Chinese majority, Han-Zu and them have been begotten. Above all, I would delve into traditional religion to understand Yi-Zu's moral culture as was already mentioned that it is my axis of treatise. Furthermore, I deliberated on how Taoism have been infiltrated Yi-Zu's moral culture, also how Han-Zu's ideological philosophies have been permeated Yi-Zu's, and what is more how to help themselves still remained in Yi-Zu's. Through my such these efforts, I analyze the aspect of embracing of Han-Zu's moral culture by Yi-Zu's and some facts of vicissitudes about it.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.330-337
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• 2018

The Korean Eutrophication Index($TSI_{ko}$) was estimated using water quality monitoring data of eight main sites in the SoOoak River watershed. The environmental characteristics of rivers were classified and evaluated using the $TSI_{ko}$ for each factor calculated by COD, T-P, and Chl-a. There is a good condition for the algae to grow due to shallow water depth, inflow of non-point source pollution during rainfall, influx of sewage treatment effluent and increase of residence time. It shows trophic state more than mesotrophication year round. Especially, in case of Chuso point, which is the inflow point of Daecheong Lake, the water quality deteriorated due to hydraulic characteristics and showed the eutrophic state. Therefore, it is necessary to establish the measures to improve the water quality through the precise monitoring of SoOak River.