• Fire Science and Engineering
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• v.32 no.5
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• pp.1-5
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• 2018

Curtains are used for shading in windows. Since most curtains are made of flammable materials and are installed vertically, curtains can be an important factor in fire spreading. Accordingly, it is important to predict fire behaviors in studies on the combustion characteristics of flammable interior decorations, such as curtains. In this study, to analyze the combustion characteristics of six kinds of curtains, which are widely used interior decorations, the oxygen index was measured at room temperature and higher temperature. As a result of the experiment, the oxygen index at higher temperature of all specimens was about 3%~7.5% lower than that at room temperature and difference of 0.2% of oxygen index show big differences in combustion phenomenon of specimens. Therefore, when flame retardancy is evaluated with the oxygen index value of flammable interior decorations, the oxygen index value at higher temperature should be sufficiently considered.

• The Korean Journal of Archival Studies
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• no.31
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• pp.139-161
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• 2012

Donald K. Sebera model can quantitatively compare the preserving environment by calculating the preserving valuation index with changing only the temperature and humidity. In this study, Donald K. Sebera model was used in order to compare and evaluate the preserving valuation index on the best condition and the worst condition in the temperature and humidity range of public records management act. As the results, the preserving valuation index in the best conditions was larger 2.47 times than the worst conditions within the preserving environment permitted in public records management act. Also, the influence of the humidity on the preserving valuation index of a paper archives as decreasing the activation energy for the hydrolysis reaction was larger rather than temperature. Thus the preserving valuation index can easily evaluate the suitability of the temperature and humidity conditions for preserving a archives. Therefore it can be used as useful tool for preservation of archives on change of the temperature and humidity.

• Journal of Sensor Science and Technology
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• v.17 no.4
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• pp.261-266
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• 2008

In this paper, we present thermal characteristics of high-temperature measurement sensor using fiber Bragg grating(FBG), including peak reflectivity, FWHM bandwidth and various normalized refractive index change along temperature variation. The temperature stability of FBG temperature sensor can be changed by varying the refractive index change and grating length. The proposed FBG temperature sensor can measure up to about $600^{\circ}C$ and 1000 hours of heating time.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.24.2-24.2
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• 2008

We have examined the relative contributions of representative space weather proxies (geomagnetic aa index) to global warming (Global temperature anomaly) and compared them with that of green house effect characterized CO2 content from 1868 to 2005. For this we used Hadcrut3 temperature anomaly (Ta) data, aa index taken at two anti-podal subauroral stations (Canberra Australia and hartland England), and the CO2 data come from historical ice core records. From the comparison between Ta and aa index, we found several interesting results: (1) the linear correlation coefficient between two parameters increases until 1990 and then decreases rapidly, and (2) the scattered plots between two parameters shows different patterns before and after 1990. A partial correlation of Ta and two quantities (aa, CO2) also shows that the geomagnetic effect (aa index) is dominant until about 1990 and the CO2 effect becomes much more important after then. These results imply that the green house effect become very important since at least 1990. For a further analysis, we simply assume that Ta (total) = Ta (aa) + Ta (CO2) and made a linear regression between Ta and aa index from 1868 to 1990. A linear model is then made from the linear regression between energy consumption (a proxy of CO2 effect) and Ta (total) - Ta (aa) since 1990. This linear model makes it possible to predict the temperature anomaly in 2030, about 1 degree higher than the present temperature, which is much larger than in the previous century.

• Environmental Analysis Health and Toxicology
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• v.26
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• pp.9.1-9.9
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• 2011

Objectives: In order to evaluate which temperature index is the best predictor for the health impact assessment of heat stress in Korea, several indexes were compared. Methods: We adopted temperature, perceived temperature (PT), and apparent temperature (AT), as a heat stress index, and changes in the risk of death for Seoul and Daegu were estimated with $^1{\circ}C$ increases in those temperature indexes using generalized additive model (GAM) adjusted for the non-temperature related factors: time trends, seasonality, and air pollution. The estimated excess mortality and Akaike's Information Criterion (AIC) due to the increased temperature indexes for the $75^{th}$ percentile in the summers from 2001 to 2008 were compared and analyzed to define the best predictor. Results: For Seoul, all-cause mortality presented the highest percent increase (2.99% [95% CI, 2.43 to 3.54%]) in maximum temperature while AIC showed the lowest value when the all-cause daily death counts were fitted with the maximum PT for the $75^{th}$ percentile of summer. For Daegu, all-cause mortality presented the greatest percent increase (3.52% [95% CI, 2.23 to 4.80%]) in minimum temperature and AIC showed the lowest value in maximum temperature. No lag effect was found in the association between temperature and mortality for Seoul, whereas for Daegu one-day lag effect was noted. Conclusions: There was no one temperature measure that was superior to the others in summer. To adopt an appropriate temperature index, regional meteorological characteristics and the disease status of population should be considered.

• Journal of Environmental Science International
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• v.26 no.12
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• pp.1399-1405
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• 2017

We compared the spatial distribution of several heat stress indices (the Wet-Bulb Globe Temperature(WBGT) index, Environmental Stress Index (ESI), and Modified Discomfort Index(MDI)) for the heat wave of June 6~August 26, 2016, in Daegu. We calculated the heat stress indices using data from the high density urban climate observation network in Daegu. The observation system was established in February. 2013. We used data from a total of 38 air temperature observation points (23 thermometers and 18 automatic weather stations). The values of the heat stress indices indicated that the danger level was very high from 0900-2000h in downtown Daegu. The daily maximum value of the WBGT was greater than or equal to $35^{\circ}C$. The differences in the heat stress indices from downtown and rural areas were higher in the daytime than at nighttime. The maximum difference was about 4 before and after 1400h, and the time variations of the heat stress indices corresponded well. Thus, we were able to confirm that the ESI and MDI can be substituted with the WBGT index.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1025-1029
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• 2003

We studied the cross-sectional profiles of deformed thermoplastics in hot embossing process and compared with melt flow index for various embossing conditions such as embossing temperature, embossing pressure and initial thickness of the thermoplastics. The fastest embossing times for complete penetration of the cavities were obtained at temperature greater than $60^{\circ}C$ above glass transition temperature (Tg). When the melt flow index of polymer is low, the penetration ratio does not become large even if the embossing pressure increases. The complete occupation of the cavities was easier obtained with high melt flow index polymer than low melt flow index polymer at the same process condition. We believe these results can be very useful for optimizing nanostructured hot embossing also known nanoimprinting process conditions.

• Journal of Environmental Science International
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• v.27 no.12
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• pp.1261-1269
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• 2018

The purpose of this study was to investigate changes in the external thermal environment, following the application of evaporative cooling systems in buildings, in response to climate change. In order to verify changes in the external thermal environment, a T-test was performed on the microclimate, Thermal Comfort Index (TCI), and building surface temperature. Differences in microclimate, following the application of the evaporative cooling system in the building, were significant in terms of temperature and relative humidity. In particular, temperature decreased by more than 7% when the evaporative cooling system was applied. According to the results of the Thermal Comfort Index analysis, the Wet-Bulb Globe Temperature (WBGT) was below the limit of outdoor activities, indicating that outdoor activities were possible. The Universal Thermal Climate Index (UTCI) values were within the very strong heat stress range when the evaporative cooling system was not applied, When the system was applied, the UTCI values were within the strong heat stress range, indicating that they were lowered by one level. The building surface temperature decreased by ~10% or more when the evaporative cooling system was applied, compared to when it was not applied. Finally, the outside surface temperature of the building decreased by ~12% or more when the system was applied, compared to when it was not applied. We conclude that the energy saving effect of the building was significant.

• Korean Journal of Optics and Photonics
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• v.21 no.5
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• pp.190-194
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• 2010

A hybrid grating sensing device based on a side-polished fiber Bragg grating (FBG) with a polymer overlay is proposed for simultaneous measurement of external refractive index and temperature. The side-polished FBG, which is insensitive to ambient index change, is utilized for detecting temperature variation, and the polymer overlay is coated on the side-polished FBG for measurement of ambient index change. The temperature sensitivities of the side-polished FBG and the polymer overlay were measured to be 0.01 nm/$^{\circ}C$ and -0.58 nm/$^{\circ}C$, respectively, in a temperature range from $30^{\circ}C$ to $100^{\circ}C$. The ambient index sensitivities of the polymer overlay were measured to be 498.8 nm/RIU in an ambient index range from 1.33 to 1.39, 694.9 nm/RIU from 1.39 to 1.42, and 1312 nm/RIU from 1.42 to 1.44.

• Atmosphere
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• v.24 no.1
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• pp.29-38
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• 2014

A characteristic of snowfall and minimum temperature variability in South Korea with respect to the variability of Arctic Oscillation (AO) was investigated. The climatic snowfall regions of South Korea based on daily new fresh snowfall data of 59 Korea Meteorological Administration (KMA) stations data corresponding to the sign of AO index during December to February 1979~2011 were classified. Especially, the differences between snowfalls of eastern regions and that of western regions in South Korea were seen by each mean 1000hPa geopotential height fields, which is one of physical structure, for the selected cases over the East Asia including the Korean Peninsula. Daily minimum temperature variability of 59 KMA station data and daily AO index during the same period were investigated using Cyclo-stationary empirical orthogonal function (CSEOF) analysis. The first CSEOF of wintertime daily AO index and that of minimum temperature of 59 KMA stations explain 33% and 66% of total variability, respectively. Correlation between principal component time series corresponding to the first CSEOF of AO index and that of temperature at the period of 1990s is over about -0.7 when that of AO index leads about 40 days.