• The Korean Journal of Community Living Science
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• v.24 no.4
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• pp.583-589
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• 2013

This study was to provide the information for optimum utilization of the air-conditioning system in the human health and energy saving perspective. Subjects were 17 male and female college students(7 males and 10 females) with normal weight. They wore a short sleeved shirt, knee length trousers, socks, and underwear(0.4clo). They were asked to choose the preferred temperature from different environmental temperatures($28^{\circ}C$, $25^{\circ}C$). The physiological responses were measured and the subjective sensation was voted during the step changes of environmental temperature, starting at $28^{\circ}C$ to $25^{\circ}C$ with $1^{\circ}C$ decrease every 20 minutes. The preferred temperature was $25.9{\pm}0.4^{\circ}C$ for males and $26.9{\pm}0.2^{\circ}C$ for females at $28^{\circ}C$ and $24.8{\pm}0.6^{\circ}C$ for males and $25.6{\pm}0.1^{\circ}C$ for females at $25^{\circ}C$. The preferred temperature decreased about $1.3^{\circ}C$ while the environmental temperature changed $3^{\circ}C$. During the environmental step changes, mean skin temperature decreased more in females while the oxygen uptake and rectal temperature were kept constant for both males and females. We found the preferred temperature was affected by the exposed temperature and the thermal sensation in the condition. Subjects preferred a lower environmental temperature when they were exposed to a lower temperature with cooler sensation. Therefore, in the perspective of human health and energy saving, it is recommended to start setting the air-conditioning temperature higher than the preferred temperature.

• The Korean Journal of Community Living Science
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• v.22 no.3
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• pp.485-491
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• 2011

This study was to present the preferred and the suggested indoor temperature of college students in winter based on their body composition. A total of 14 subjects(6 males and 8 females) participated in this study. They sat in a climatic chamber controlled at $24^{\circ}C$ wearing experimental garments(0.7clo). The air temperature decreased $1^{\circ}C$ every 15 minutes until it reached $19^{\circ}C$. After the stepwise temperature change, subjects were asked to select a comfortable air temperature by dialing the temperature control switch inside the chamber. The preferred temperature was determined when subjects did not change the air temperature for 10 minutes. The measurements were oxygen consumption, rectal temperature, skin temperature, and subjective sensation. Main results are as follows. In a mild cold condition, females demonstrated lower oxygen consumption and mean skin temperature than males while keeping a constant rectal temperature. Females increased rectal temperature and decreased mean skin temperature greater than males from $24^{\circ}C$ to $19^{\circ}C$. Males showed larger oxygen consumption increase than females. It appears that the thermo-physiological responses in a mild cold condition might be different between males and females. The preferred winter indoor temperature was $22.3^{\circ}C$ for males and $23.4^{\circ}C$ for females, and the suggested temperature was $21^{\circ}C$ for males and $23^{\circ}C$ for females.

• Journal of the Korean Institute of Rural Architecture
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• v.20 no.2
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• pp.29-36
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• 2018

Even in modern times, we are accustomed to the lifestyle of floor heating system in which the floor is heated for warmth like Ondol, which is the traditional Korean heating system. So, this study was designed to understand the preferred floor temperature through the questionnaires targeting the local residents living in K region. This study would also find out the floor temperature which is preferred by young people and old people through the experiments. The findings are as follows; (1) the old people do not prefer the temperature higher than young people do. It was found that the old people prefer the floor temperature of $40^{\circ}C$ under the air temperature of $20^{\circ}C$ or the floor temperature of $41^{\circ}C$ under the air temperature of $20^{\circ}C$. (2) Both young people and old people tend to like the average skin temperature of $35.5^{\circ}C$. The skin temperature which both young and old people like was $35.2^{\circ}C$ under the air temperature of $24^{\circ}C$ and the skin temperature preferred by young people was $0.4^{\circ}C$ higher than that preferred by under the air temperature of $20^{\circ}C$ (p<0.01). (3) It was found in the questionnaires that the young people prefer the higher floor temperature in terms of age and that the people who get older in their 50s or higher tend to prefer the lower temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.6
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• pp.294-300
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• 2014

In this study, we investigated and evaluated the air conditioning operation of the driver according to the temperature difference between the inside and outside of a car parked outside during the summer. We suggest including a comfort mode to the car air conditioning system to improve the thermal comfort of the driver, in which the comfort can be maintained for a longer time. For the a result of our experiment, in the cases with temperature of above $45^{\circ}C$ inside of the car, the subjects preferred strong air blow with the face and the arms in the direction of the blow. In the cases with temperature of below $40^{\circ}C$ inside of the car, the subjects preferred lower volume of air blow. In the temperature below $28.1^{\circ}C$ inside of the car, the mean temperature on the skin of the driver reached the comfort zone.

• The Korean Journal of Community Living Science
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• v.22 no.1
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• pp.155-161
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• 2011

This study was designed to present the preferred indoor temperature of college students in summer based on their body composition. A total of 19 subjects, 10 females and 9 males, participated in this study. They sat in a climatic chamber controlled at $27^{\circ}C$ wearing a short sleeved shirt and short trousers. The air temperature decreased by $0.5^{\circ}C$ every 10 minutes until it reached $24^{\circ}C$. Oxygen uptake, rectal temperature, and skin temperature, subjective sensation were measured and recorded. Females increased the rectal temperature and decreased mean skin temperature in an air conditioned environment, showing better physiological responses. But they felt more thermal discomfort than males. The preferred indoor temperature of college students in summer was $25.3^{\circ}C$, $25.7^{\circ}C$ for females and $24.97^{\circ}C$ for males.

• The Korean Journal of Community Living Science
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• v.21 no.4
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• pp.633-639
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• 2010

This study was carried out to compare human thermoregulatory responses and preferred air temperature by feet immersion between summer and winter in terms of thermal comfort. Five healthy female university students participated in the study as subjects. They experienced feet immersion at $40^{\circ}C$ of water in the climatic chamber of $24^{\circ}C$, 50%RH from 19:30 to 21:00 in the summer and winter, respectively. Rectal temperature gradually decreased and maintained $0.08^{\circ}C$ lower in winter than summer, while mean skin temperature changed $0.4^{\circ}C$ greater in winter than summer(p=0.00). Air temperature selected by each subject for their thermal comfort revealed $0.8^{\circ}C$ higher in summer than winter(p=0.06). The results obtained suggest an increase in human thermoregulation and be used as preliminary data to maintain optimal indoor temperature in summer and winter.

• Journal of Korean Society on Water Environment
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• v.38 no.1
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• pp.19-30
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• 2022

Climate change has increased the average air temperature. Rising air temperature are absorbed by water bodies, leading to increasing water temperature. Increased water temperature will cause eutrophication and excess algal growth, which will reduce water quality. In this study, long-term trends of air and water temperatures in the Han-river basin over the period of 1997-2020 were discussed to assess the impacts of climate change. Future (~2100s) levels of air temperature were predicted based on the climate change scenarios (Representative concentration pathway (RCP) 2.6, 4.5, 6.0, and 8.5). The results showed that air and water temperatures rose at an average rate of 0.027℃ year^-1 and 0.038℃ year^-1 respectively, over the past 24 years (1997 to 2020). Future air temperatures under RCP 2.6, 4.5, 6.0, and 8.5 increased up to 0.32℃ 1.18℃, 2.14℃, and 3.51℃, respectively. An increasing water temperature could dissolve more minerals from the surrounding rock and will therefore have a higher electrical conductivity. It is the opposite when considering a gas, such as oxygen, dissolved in the water. Water temperature also governs the kinds of organisms that can live in rivers and lakes. Fish, insects, zooplankton, phytoplankton, and other aquatic species all have a preferred temperature range. As temperatures get too far above or below this preferred range, the number of individuals of the species decreases until finally there are none. Therefore, changes of water temperature that are induced by climate change have important implications on water supplies, water quality, and aquatic ecosystems of a watershed.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.333-339
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• 1999

$RuO_2$ thin films were prepared with various deposition conditions by rf magnetron sputtering. The films were annealed in vacuum, air, and air-vacuum, after that, the structural and electrical properties of the films were investigated. As the substrate temperature increases, the preferred orientation of the films changes from (101) to (200), and the grain size increases; especially, at $500^{\circ}C$, the size considerably increases. The preferred orientation of the films changes from (200) to (101) and the roughness of surface increase with the increase in oxygen partial pressure. The lowest value of resistivity of $RuO_2$ we prepared is $1.5\times 10^{-5}\Omega\codt\textrm{cm}$ at the conditions of $400^{\circ}C$ and 10% of oxygen partial pressure. After the processes of annealing, the films deposited at $400^{\circ}C$ and a oxygen partial pressure of 10% were relatively stable. The films deposited at $500^{\circ}C$ have denser structure and smoother surface when the films are annealed in vacuum after annealing in air.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.497-501
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• 2009

Effect of angle of supply air on cooling and heating performances of office space is studied by numerical simulation. For a constant air volume(CAV) air-conditioning system, air is supplied vertically($90^{\circ}$) and horizontally($10^{\circ}$). Due to buoyancy, the supply angle affects the performance of cooling and heating. In cooling, since the cold supply air tends to move downward due to its high density, horizontal supply angle is better for uniform temperature distribution. In heating, however, vertical supply angle is preferred for better mean and uniform temperature distribution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.2
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• pp.72-75
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• 2008

Zinc oxide (ZnO) thin films were prepared by a sol-gel method. The structural and electrical properties were investigated by varying drying and annealing temperatures. The thin films were coated (250 nm) by spin-coating method on glass substrates. The optimum drying temperature of ZnO thin films was 300$^{\circ}C$ where the resistivity was the lowest and the preferred c-axis orientation was the highest. The annealing was carried out in air and inert atmospheric conditions. The degree of the preferred c-axis orientation was estimated. The highest preferred c-axis orientation was recorded at 600$^{\circ}C$. The preferred c-axis orientation and grain growth resulted in the mobility enhancement of the ZnO thin films, and the lowest resistivity was 0.62${\Omega}{\cdot}cm$ at 600$^{\circ}C$.