• Elastomers and Composites
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• v.55 no.1
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• pp.51-58
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• 2020

In this study, the thermal oxidation of raw natural rubber (NR) was investigated under controlled conditions by optical image and fourier transform infrared (FT-IR) analysis. The thermal oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at 80℃ under low humidity conditions to completely exclude moisture and restrict light oxidation. Images of the thin film of raw NR were obtained before and after thermal oxidation. FT-IR absorption spectra were measured in the transmission mode at different thermal exposure times. The thermal oxidation of NR was examined by the changes in the absorption peaks at 3449, 1736, 1447, 1377, 1242, 1072, and 833 cm^-1, which corresponded to a hydroxyl group (-OH), a carbonyl group (-C=O) from an aldehyde and a ketone, a methylene group (-CH₂-), a methyl group (-CH₃), a carbon-oxygen single bond (-C-O) from an epoxide, a carbon-oxygen bond (-C-O) from an ether, an alcohol, a peroxide, or a cyclic peroxide, and a cis-methine group (cis-CCH₃=CH-), respectively. In the initial stage of thermal oxidation, two different types of free radicals were produced quickly and randomly by the homolytic cleavage of a double bond and allylic hydrogen abstraction. Aldehydes and ketones were formed from chain scissions of the double bonds and alcohols were produced from allylic hydrogen abstraction at the methylene or methyl groups. Two reactions seemed to proceed competitively with each other. At a later stage, oxidative crosslinks seemed to dominate through the combination of free radicals such as an allyl radical (CH=CHCH₂·), alkoxy radical (RO·), and peroxy radical (ROO·) and the reaction of a hydroperoxide (-ROOH) with a double bond. The image obtained after thermal oxidation showed hardening without cracks. Based on these observations, a plausible two-step mechanism was suggested for chain hardening caused by the thermal oxidation.

• Korea Science and Art Forum
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• v.36
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• pp.11-22
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• 2018

This study recent changes in urban thermal environment caused by climate change generate diverse problems such as urban heat island effects, heat wave, and drought. Under this condition, with the increased perception and expectation of the quality of life, the urban citizens' desire for outdoor activities is increasing. This study conducted the thermal environment analysis focusing on the urban ecological park used by many urban citizens, and also suggested the renovation measures for urban ecological park considering the thermal environment. As the research site, the ecologically-favorable Gildong Ecological Pak with diverse space composition was selected. The measuring items were measured and analyzed by dividing them into thermal environment index and thermal comfort index. In the results of analysis in each type of park space, the forest zone showed the most favorable result. Based on such results, total three kinds of renovation measures for urban ecological park considering the thermal environment were suggested. Through this, the urban ecology park renovation plans were presented in three ways. The results of this study are meaningful in that it can be used as a base material for creating an ecological park considering the thermal environment.

• Journal of Acupuncture Research
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• v.18 no.1
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• pp.40-49
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• 2001

Background and Purpose : There have been many studys about the relationship between the meridians and the acupoints of the twelve meridians, but no study about the extra points. To verify Dong-Shi acupoints, a kind of extra points, we studied the effects on the thermal changes of the ankle region following acupuncture on the Wu-Hu. Object and Methods : This study was researched into clinical statistics for 45 healthy normal students. The object was divided into two groups. One was the control group and the other was the acupuncture group. The acupuncture group was divided into two groups ; ACU-up : The class of ascent thermal change among acupuncture group. ACU-dn : The class of descent thermal change among acupuncture group. First, in the control group, we took a picture at the ankle region(BL60, BL62, GB40, ST41) without any stimulation with the Digital Infrared Thermal Imaging System and did after 10 minutes respectively. Second, in the acupuncture group, we took a picture without any stimulation and then acupuncture on Wu-Hu and took a picture after 10 minutes in the same way respectively. Results : 1. In the control group, average thermal change of BL60, BL62, GB40 and ST41 was decreased(about $0.2^{\circ}C$) after 10 minutes. 2. The skin temperature of all measured parts was significantly lower in the ACU-dn group after 10 minutes. 3. There were no significant differences of thermal change between the control and the acupuncture group, between the control and ACU-up group after 10 minutes. Conclusion : This result indicated that the acupuncture on the Wu-Hu was effective at the ankle region. And so the more study is needed continuously.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.1-8
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• 2010

We determined oxidative stress caused by thermal stress in olive flounder Paralichthys olivaceus based on the altered-mRNA expression and enzymatic activity of two key antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), along with monitoring of several other biomarkers. When the fish were exposed to acute thermal change (from $20^{\circ}C$ to $25^{\circ}C$ and $30^{\circ}C$), the expression and activity of both enzymes were significantly higher at elevated temperatures ($25^{\circ}C$ and $30^{\circ}C$) than at $20^{\circ}C$. Lipid peroxidation (LPO) was also higher at $25^{\circ}C$ and $30^{\circ}C$ than at $20^{\circ}C$. In addition, the plasma $H_2O_2$ concentration was significantly increased by thermal stress. Furthermore, we investigated changes due to thermal stress by measuring levels of plasma alanine aminotransferase (AlaAT) and aspartate aminotrasferase (AspAT). Both were significantly increased by thermal stress. As an immune indicator, the lysozyme concentration was lower at $30^{\circ}C$ than at $20^{\circ}C$, indicating that thermal stress decreases immune function. Therefore, thermal stress could induce oxidative stress and suppress immune function and can cause physiological stress.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.229-240
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• 2022

Purpose : In this study, using Oyster Shell Thermal Therapy for metabolic diseases, we analyzed the effect of immune and inflammation-related variables and respiratory health-related variables of test subjects to verify the effect of improving respiratory health. Methods : In this study, 26 patients with metabolic diseases were divided into an experimental group (N=13) and a control group (N=13). After Oyster Shell Thermal Therapy (four weeks/three times a week/1 hour per time), metabolic disease-related variables and immune and respiratory health-related variables were measured and compared between the two groups. The conclusion of this study is as follows: Results : After the four-week Oyster Shell Thermal Therapy, in terms of changes in the metabolic disease-related variables, the control group exhibited a higher increase in TC and LDL-C levels than the experimental group. In the case of glucose, the experimental group showed a decrease after the experiment (p<.05). After the four-week thermotherapy, a statistically significant interactive effect occurred in natural killer (NK) cells among the immune-related variables. According to the results of a post-experimental analysis, the control group showed a higher decrease in NK cells than the experimental group (p<.05). After the 4-weeks thermotherapy, the experimental group showed a greater increase in maximum oxygen intake of the respiratory health-related variables than the control group. Conclusion : Based on a comprehensive review of the study results, the subjects who underwent the four-week Oyster Shell Thermal Therapy exhibited positive physical changes in metabolic disease-related variables as well as immune and respiratory health-related variables, which demonstrates the effectiveness of Oyster Shell Thermal Therapy on immune and respiratory health. Accordingly, it is recommended to conduct long-term Oyster Shell Thermal Therapy with various models in terms of the size and shape.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.26-31
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• 2004

The radiation-induced changes taking place in poly(vinylidene fluoride) (PVDF) exposed to $^{60}Co$ $\gamma-ray$ irradiation were investigated in correlation with the applied doses. Samples were irradiated in air at room temperature by $^{60}Co$ $\gamma-ray$ to doses in the range of 200 to 1000kGy. Various properties of the irradiated PVDF were studied using FTIR, differential scanning calorimetry (DSC), gel fraction and elongation. $^{60}Co\gamma-ray$ irradiation was found to induce changes in chemical, thermal, mechanical and structural properties of PVDF and such changes vary depending on the radiation dose.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.218-226
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• 1996

This study was performed to evaluate the possibility of pulpal damage by measuring temperature change occured in dentin according to the thickness of dentin, the time of irradiation and the output of laser energy when the dentin surfaces were irradiated with Nd-YAG laser under water coolant and no water coolant. Sound upper and lower molar teeth were sectioned with 1mm, 1.5mm and 2mm thickness of dentin discs and divided into 4 groups by dentin thiness. 0.5 watt, 1 watt, 1.5 watt and 2 watt-energied beam of pulsed 10 p.p.s of Nd : YAG laser was applied respectively to dentin surfaces for 8 secs and 16 secs when water coolant is used or not.Ant then the temperature changes occurd in dentin were measured at opposite surfaces of laser-irradiated dentin surfaces with digital thermometer. The results were as follow. 1. When the amount of irradiated energy was same, the temperatue changes of dentin were higher as the thickness of dentin discs was thinner(p<0.01). 2. When the amount of irradiated energy and the thickness of dentins were same, The temperature changes of dentin were lower under water coolant than under no water coolant in all groups(p<0.01). 3. With the increase of time of irradiation, the temperature changes of Dentin became higher in all groups and were steeply increased at initial period of irradiation of laser. 4. Under the same thickness of dentin, the temperature changes of dentin became higher as irradiated energy was increased. These results suggest that when the beam of Nd : YAG Laser is irradiated to dential hard tissue, amount of irradiating energy, thickness of dentin, using water coolant must be considered in order to minimize thermal damage of the pulp.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.256-259
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• 2005

Analysis of behavior pattern and thermal response during bathing and showering provides important fundamental data when developing an automatic bathing/showering system. The behavior pattern and physiological changes during bathing/showering were measured und analyzed for the aged male group. We recorded the volunteers showering at front, back, left and right view using four CCTV cameras in order to study the behavior pattern during showering. The photographic data were analyzed by counting the frequencies of body contact and identifying zones where hands could reach. In order to study the thermal response, we measured the blood pressure (B.P), heart rate (H.R), body temperature (B.T.), breathing rate (B.R) for the different water temperatures and the locations of immersion for the young and old age groups. The results showed that the frequencies of body contacts were varied for different body sections. Also there were some body sections where hands could not be reached because of reduced pliability and muscular strength of the aged group. But we observed rather uniform body contact frequencies when a towel was used. In partial immersion bath experiments, we observed the changes of B.P. H.R and B.T in the case of young and old age groups, and the changes were more significant in the young age group.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1403-1415
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• 2019

Urban population growth and consequent rapid urbanization involve some thermal environmental problems in the cities. Monitoring of thermal environments in urban areas such as hot spot analysis is required for effective actions to resolve these problems. This study selected 14 dongs and surrounding administrative districts of Sejong city as study areas and analyzed the characteristics of changes in surface temperature due to the urban expansion in the summer from 2013 to 2018. In the study, the surface temperature distributions in the study areas were plotted using surface temperature values from Landsat 8 and NDVI (Normalized Difference Vegetation Index) and NDBI (Normalized Difference Built-up Index) based on KOMPSAT 2/3 data, and the patterns of surface temperature changes with urban expansion were discussed using the estimated NDVI and NDBI. In particular, the distinct urbanization in the study areas were selected for case studies, and the cause of the changes in the hot spots in the regions was analyzed using high-resolution KOMPSAT images. This study results present that hot spots appeared in urbanized regions within the study areas, and it was plotted that the lower the NDVI values and the higher the NDBI values indicate the temperature values are high. The land surface temperature and satellite-based products were used to divide the study areas into continuously urbanized regions and rapidly urbanized regions and to identify the different characteristics depending on land covers. In the regions with distinct surface temperature changes by urbanization, the analysis using high-resolution KOMPSAT images as presented in this study could provide effective information for urban planning and policy utilization in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.325-330
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• 2000

Alginate obtained from brown algae had various physicochemical and rheological properties and could used as a dietary fiber, However, alginate has not been widely applied to the food industry, since it had high viscosity, high gelling effect conjugated with some mineral, and low solubility. To improve functionality of alginate, partially develymerized alginates, which was water-soluble dietary fiber were obtained by hydrolysis of alginate from the sea tangle, Laminaria japonicus, heated at $121^{\circ}C$. Effects of depolymerization of alginate on the changes of viscosity and average molecular weight, block composition ratio of mannuronate to guluronate (M/G ratio), chemical properties using $PT-IR, ^1H-NMR, and ^(13)C-NMR$ spectrum were investigated. The average molecular weight and viscosity of the alginate were rapidly decreased with the thermal decomposition, and estimated to be 1,307,415 dalton and 284,000 cps, before heating, 728,106 and 3,940.29 cps after 30 min heating, 102,635 and 22.22 cps after 2.5 hrs heating, 51,205 and 12.05 cps after 3 hrs, and 10,049 and 4.28 cps after 6.5 hrs, respectively. The M/G ratio was increased with the heating time, while MM-block did not show any changes and GG-block diminished. The results of $FT-IR, ^1H-NMR and ^(13)C-NMR$ spectrum suggested that changes of molecular structure did not occur by the thermal decomposition.