• 한국초전도ㆍ저온공학회논문지
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• 제14권4호
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• pp.46-49
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• 2012

The selection of the temperature sensor in the cryogenic system depends on the temperature range, shape and accuracy. The accuracy of the temperature sensor is essential to improve the reliability of experiment. We have developed the variable temperature cryostat using a two-stage cryocooler. In order to reduce heat load, thermal shield is installed at the first stage with MLI (Multiple layer insulation). We have also developed the sensor holder calibrating more than twenty sensors at the same time for saving time and money. The system can calibrate sensor at variable temperature by controlling electric heater. In this paper, we present design and fabrication of variable temperature cryostat and representative result of Cernox sensor calibration.

• Tribology and Lubricants
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• 제35권6호
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• pp.362-368
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• 2019

In this study, mechanical and tribological properties were investigated by varying the process temperature (50, 100, 125 and 150℃) to reduce internal stress. The internal stress reduction by thermal dissociation ta-C coating film with increasing temperature is confirmed through the curvature radius of the ta-C coating according to the temperature of the SUS plate. As the coating temperature increased, the mechanical properties (hardness, modulus, toughness) deteriorated, which is in agreement with the Raman analysis results. As the temperature increased, the sp² phase ratio increased owing to the dissociation of the sp³ phase. The friction and wear properties are related to the process temperature during ta-C coating. Low friction and wear properties are observed in high hardness samples manufactured at 50℃, and wear resistance properties decreased with increasing temperature. The contact area is expected to increase owing to the decrease of hardness(72 GPa to 39 GPa) and fracture toughness with increasing temperature which accelerated wear because of the debris generated. It was confirmed that at process temperature of over than 100℃, the bond structure of the carbon film changed, and the effect of excellent internal stress was reduced. However, the wear resistance simultaneously decreased owing to the reduction in fracture toughness. Therefore, in order to increase industrial utilization, optimum temperature conditions that reduce internal stress and retain mechanical properties.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.376-382
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• 2011

Since the Industrial Revolution has caused global change by using of a fossil fuel, a reckless and growth-oriented development. A global mean temperature since 19th century has climbed up 0.4~$0.8^{\circ}C$. Our country, afterwards, global warming has increased the temperature every season. After The Kyoto Protocol regarding a greenhouse gas reduction goal took effect, be situations that decrease of greenhouse gas was acutely required. Therefore, interest of utilization of the new & renewable energy is increasing everyday. In advanced research, we shows that at first divided a country to nine range by natural geography, and second executed Meteorological data analysis of recent 30 years considering level of significance by nine range. The results of advanced research are that the similarities are low because there are the regions that temperature deviation of the similar climate regions is large in winter season, and there are not characteristics of clear discrimination of temperature. This study shows that at first divided a country to six range by temperature range, and second executed Meteorological data analysis of recent 30 years considering level of significance by six range. The results of this study are that in heating load calculation of building, periodic temperature data management is required because facility capacity and cost are affected greatly by outdoor temperature, and temperature by climate range needs consideration of pertinent area. Ground temperature was assumed of the weather in region, the ground and soil. Lastly, we were able to know that establishment of climate region by temperature range can be useful policy making and plans of design of the horticultural facilities and architectures.

• 한국군사과학기술학회지
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• 제18권1호
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• pp.55-65
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• 2015

This paper describes the results of a temperature analysis of Korea and its neighbor regions for temperature specification of weapon systems to be deployed in Korea, and introduces the concept of a standard deviation frequency of occurrence which represents a frequency of yearly occurrence. On the basis of this analysis, reasonable operational temperatures for the Korea weapon systems are recommended, and the regional frequency of yearly occurrence of temperatures worse than recommended operational temperatures in each country regions are presented.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.740-741
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• 2015

the downscaled air temperature data over study region for the projected 2001 - 2099 period were then ensemble averaged, and the ensemble averages of 6 realizations were compared against the corresponding historical downscaled data for the 1961 - 2000 period in order to assess the impact of climate change on air temperature over study region by graphical, spatial and statistical methods. In order to evaluate the seasonal trends under future climate change conditions, the simulated annual, annual DJF (December-January-February), and annual JJA (June-July-August) mean air temperature for 5 watersheds during historical and future periods were evaluated. From the results, it is clear that there is a rising trend in the projected air temperature and future air temperature would be warmer by about 3 degrees Celsius toward the end of 21^st century if the ensemble projections of air temperature become true. Spatial comparison of 30-year average annual mean air temperature between historical period (1970 - 1999) and ensemble average of 6-realization shows that air temperature is warmer toward end of 21^st century compared to historical period.

• 센서학회지
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• 제26권2호
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• pp.141-147
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• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.934-939
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• 1998

This study discusses the results of adiabatic temperature rise tests which were performed considering various parameters, such as cement type, water-cement ratio, unit cement weigh, admixtures and placing temperature, which influence the temperature rise(K) and reaction velocity ($\alpha$). Theadiabatic temperature rise models obtained from this study are similar to those of Japan Concrete Institute. The models to calculate temperature rise and reaction velocity could be used the analysis f concrete thermal stress.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.25-28
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• 2005

The experimental results on the mechanical behavior of high-strength concretes subjected to high temperature were presented. Main variables were heating temperature, heating continuance time, and cooling condition. The compressive strength properties of high strength concrete(HSC) varied differently with temperature than those of normal strength concrete(NSC). HSC had higher rates of strength loss than NSC in the temperature range of between $20^{circ}C$ and $400^{circ}C$. Especially, HSC exploded in $400^{circ}C$ of high temperature.

• Macromolecular Research
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• 제8권2호
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• pp.89-94
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• 2000

A semi-interpenetrating network (IPN) was prepared for a temperature-sensitive polymer system composed of sodium alginate and poly (N, N-dimethylaminoethyl methacrylate (DMAEMA)-co-ethyl acrylamide (EAAm)). The role of sodium alginate is to provide crosslinked network and that of poly(DMAEMA-co-EAAm) is to provide temperature responsiveness to the polymer system. Semi-IPN gel shows temperature-induced swelling transition at the same temperature of the lower critical solution temperature of poly(DMAEMA-co-EAAm) and its swelling kinetics is manipulated by the control of crosslinking densitv.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.431-433
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• 2006

Accurate information on the ground surface temperature is essential for design of a borehole heat exchanger and thus ensuring the performance of a ground source heat pump system along with knowledge on thermal diffusivity and conductivity of ground. In this study we analyzed the shallow subsurface temperature monitoring data of 58 Korea Meteorological Administration synoptic stations. As a result, we compiled mean annual ground surface temperature distribution map using multiple regression analysis of the monitoring data.