• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.11
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• pp.581-586
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• 2015

In this study, an analysis was performed on the performance of the solar water heating system with geo-thermal heat pump for a detached house. This system has a flat plate solar collector ($8\;m^2$) and a 3 RT heat pump. The heat pump acts as an auxiliary heater of the solar water heating system. These systems were installed at four individual houses with the same area of $100\;m^2$. The monitoring results for one year are as follows. (1) The average daily operating time of the solar system appeared to be 313 minutes in spring (intermediate season), and 135 minutes and 76 minutes in winter and summer respectively. The reason for the short operating time in summer is the high storage temperature due to low water heating load. The high storage temperature is caused by a decrease in collecting efficiency as well as by overheating. (2) The geothermal heat pump as an auxiliary heater mainly operates on days of poor insolation during the winter season. (3) Despite controlling for total house area, hot water consumption varies greatly according to the number of people in the family, hot water usage habits, etc. (4) The yearly solar fraction was 69.8 to 91.5 percent, which exceeds the maximum value of 80% as recommended by ASHRAE. So the solar collector area of $8\;m^2$ appeared to be somewhat greater for the house with an area of $100\;m^2$. (5) The observed annual efficiency of solar systems was relatively low at 13.5 to 23.6%, which was analyzed to be due to the decrease in thermal efficiency and the overheating caused by a high solar fraction.

• Economic and Environmental Geology
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• v.50 no.1
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• pp.45-59
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• 2017

In this research, we have extracted historical records regarding the geotechnology from the Goryeosa and the Annals of the Joseon Dynasty which are rated as ancient books that have objective views in the Goryeo Dynasty and the Joseon Dynasty in order to understand the national awareness and the social situation of the past events. We used the Korean history database system of National Institute of Korean History (NIKH) and collected related records by searching specific keywords such as volcano, mining, hot spring, and meteorite. According to the historical records, geological events such as the volcano and meteorite were regarded as important issues which were enough to be recorded in annals and surveyed by the dispatched government officials to the fields of events. In case of the hot springs, government officials conducted explorations of hot springs at king's orders and developed the potential areas of hot springs. Among the historical records on mining, the contents of geotechnology including the contents about discovered minerals and its locations can be easily found from those ancient books. Especially, it is possible to understand the history of geotechnology such as an establishment of modern organizations and a capitalistic flow for development through the history of the mining in the late Joseon Dynasty.

• The Journal of Engineering Geology
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• v.18 no.2
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• pp.185-190
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• 2008

Nine wells have been developed for uses of thermal waters at the Icheon hot spa area. Drilling depths of those hot spring wells range from 166 to 294 m and their piezometric heads are located at about 50 m below the surface. Using the differences between the surface and bottom temperatures within all boreholes, we can simply estimate geothermal gradient in this area. Thus, we obtained the highest, lowest and average gradient values as $64^{\circ}C/km$ from SB-2 well, $45^{\circ}C/km$ from SB-1 well and approximately $54.28^{\circ}C/km$, respectively. However, observing the MRD-2 well additionally drilled into the depth of 996 m, we found out that this study area has widely experienced the temperature disturbance due to thermal groundwater penetration through the fracture systems within the depth of 720 m. Unlikely this phenomenon, we can conclude that the groundwater flow below the depth of 720 m does not exist. Therefore, using only those temperature data below the 720 m depth, we can estimate reasonable geo-thermal gradient values as $33^{\circ}C/km$ in this study area. Pumping test shows that outflowing temperature is $36^{\circ}C$ corresponding to the temperature logging data at 720 m depth.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.325-330
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• 2001

One of the principal components of the KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak structure is the vacuum vessel, which acts as the high vacuum boundary for the plasma and also provides the structural support for internal components. Hyundai Heavy Industries Inc. has performed the engineering design of the vacuum vessel. Here the overall configuration of the KSTAR vacuum vessel was briefly described and then the design methodology and the analysis results were presented. The vacuum vessel consists of double walls, several ports, leaf spring style supports. Double walls are separated by reinforcing ribs and filled with baking/shielding water. The overall external dimensions of the main body are 3.39 m high, 1.11 m inner radius, 2.99 m outer radius, and made of SA240-316LN. The vacuum vessel was designed to be capable of achieving the base pressure of $1\times10^{-8}$ Torr, and also to be structurally capable of sustaining the vacuum pressure, the electromagnetic and thermal loads during plasma disruption and bakeout, respectively. The vacuum vessel will be baked out maximum $150^{\circ}C$ by hot pressurized water through the channels formed between double walls and the reinforcing ribs. A 3-D temperature distribution and the resulting thermal loads in the vessel were calculated during bakeout. It was found that the vacuum vessel and its supports were structurally rigid based on the thermal stress analysis. The maximum electromagnetic loads on the vacuum vessel induced by eddy and halo currents resulting from the engineering plasma radial and vertical disruption scenarios have been estimated. The stress analyses have been performed based on these electromagnetic loads and the resulting stresses at he critical locations of the vacuum vessel were within the allowable stresses.

• Composites Research
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• v.15 no.4
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• pp.17-22
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• 2002

Small diameter composite helical springs (CS) are developed using a hot plated mold for reinforcement of common optical fiber jumper cord (OJC). The outer diameters of the springs are about 2 ~ 3mm. These springs are inserted into the OJC to protect the damage of an optical fiber from the sudden lateral load. Two types of CS, Yarn type (Y-type) and Band type (B-type), are manufactured to compare the effectiveness for the damage protection. The experimental works were conducted to check the effect of the CS covered around OJC on the mechanical and optical properties. Experimental observations show a considerable effect on the flexural resistance, hence slowing down the deterioration of the optical power by the internal damage of the fiber. Obtained main results are as follows: (1) Y-type CS has better protection abilities to lateral loading than B-types. (2) Compared with bare OJC, CS-OJC has less power loss under the loading. (3) OJC covered with the composite coil spring has a possibility for a practical usage with full fruits.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.442-450
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• 2015

Climate temperature affects animal production. This study was conducted to evaluate whether climatic conditions affect beef carcass characteristics of Korean cattle steers. The monthly carcass characteristics of Korean cattle steers (n = 2,182,415) for 8 yr (2006 through 2013) were collected from the Korean Institute for Animal Products Quality Evaluation. Daily climate temperature (CT) and relative humidity (RH) data were collected from the Korean Meteorological Administration. Weather conditions in South Korea during summer were hot and humid, with a maximum temperature of $28.4^{\circ}C$ and a maximum RH of 91.4%. The temperature-humidity index (THI), calculated based on CT and RH, ranges from 73 to 80 during summer. Winter in South Korea was cold, with a minimum temperature of $-4.0^{\circ}C$ and a wind-chill temperature of $-6.2^{\circ}C$. Both marbling score (MS) and quality grade (QG) of Korean cattle steer carcasses were generally best (p<0.05) in autumn and worst in spring. A correlation analysis showed that MS and QG frequencies were not associated (p>0.05) with CT. Yield grade (YG) of Korean cattle steer carcasses was lowest (p<0.05) in winter (November to January) and highest in spring and summer (May to September). A correlation analysis revealed that YG frequency was strongly correlated ($r{\geq}0.71$; p<0.01) with CT and THI values. The rib eye area, a positive YG parameter, was not associated with CT. Backfat thickness (BT), a negative YG factor, was highest in winter (November and December). The BT was strongly negatively correlated ($r{\leq}-0.74$; p<0.01) with CTs. Therefore, the poor YG during winter is likely due in part to the high BT. In conclusion, YG in Korean cattle steer carcasses was worst in winter. QGs were not associated with winter or summer climatic conditions.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.6
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• pp.590-605
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• 1987

The purpose of this study was to investigate thermal environmental factors, thermal clothing properties, and thermal sensation of the office workers in four selected office buildings in Seoul, and to determine the effect of thermal environmental factors and clothing insulation to the thermal sensation of the subjects. The subjects selected from each office were 5 males and 5 females at a time. Thermal environmental factors(DBT, GT, RH, MRT, $ET^{\ast}$) and clothing variables such as clothing weight per body surface $area(g/m^2)$ and estimated clothing insulation values(clo) were significantly different among each seasons(p<0,001). Means of $ET^{\ast}$ and estimated clothing insulation values of each season were as follows; Winter; $20.84^{\circ}C$ $ET^{\ast}$ with 0.72 clo for male and 0.79 clo for female Spring and fall; $23.65^{\circ}C$ $ET^{\ast}$ with 0.59 clo for male and 0.68 clo for female Summer; $26.00^{\circ}C$ $ET^{\ast}$ with 0.47 clo for male and 0.53 clo for female. In comparison these data with ASHRAE Standard, the subjects were predicted to feel comfort-able in spring and fall, and slightly hot in summer and slightly cold in winter because of high and low clo respectively. But the result of this survey showed more than $80\%$ of the occupants were thermally comfortable at a given environmental temperature and clo.

• Korean Journal of Oriental Medicine
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• v.11 no.2
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• pp.23-33
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• 2005

Four Properties and five Flavors of Drugs is interpreted by adaptation of human body to the environmental theory(天人相應). The Structural model of the body is compared with sky, earth, sun and moon (天, 地, 日, 月). The natural changes of the four seasons give rise to that of Four Properties and five Flavors of Drugs. On equal terms it is happened in our body. On this study we can draw an analogy between sky, earth, sun & moon (天, 地, 日, 月) and the body. The six bu(六腑) is related to the earth, the five ju(五主) to the sky, the five jang(五臟) to the sun, the meridians system (經絡) to the moon. When spring, the air is warm, the water element of the earth is ascending, and the earth gives birth to the sour flavor. Like this, the water element is absorbed by six bu and then is ascended to the meridian system. When summer, the air is hot and the water element of the earth is floated, the earth make the bitter flavor. In the same way, the six bu absorbed the hot air from the five ju and the water element is quickly absorbed by six bu and then the water element is ascended to the meridian system. When rainy season (長夏), the earth creates the sweet flavor The sweet flavor give warmer energy to the five jang and the six bu. When autumn, the earth change the sweet flavor into pungent. The earth gives warmer energy to the sky, because of cool weather According to same process, the pungent flavor give warmer energy to the five jang and the six bu, and the meridian system gets back the water element from the five ju. When winter, the air is cold and the water element of the earth is hidden. The sky and the earth are not interchangeable. At that time, the earth produce the salty flavor and the water element is keeping in the meridian system.

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.148-155
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• 2011

Thermal treatment techniques are used for modifying wood and wood-based materials to improve dimensional stability and hygroscopicity. This study investigated the effects of press pressure and temperature on density, vertical density profile, thickness swelling and surface hardness of eucalyptus wood boards. The experimental wood boards were prepared from Turkish River Gum ($Eucalyptus$ $camaldulensis$ Dehn.). The surface hardness value increased with increasing press pressure in the treated groups. The application of a higher pressure at the same temperature level increased the amount of swelling of wood. It means that it is not needed for application of higher pressure to enhance the dimensional stability of wood. It is expected that it is possible to produce increased hardness, dimensional stability and durability by application of hot pressing treatment. This research showed that different press pressure and temperature values should be used to improve the performance properties of eucalyptus wood so that the end-use of the wood materials could be expanded.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.303-306
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• 2006

Using a variety of chemical geothermometers we estimate the temperature of a deep geothermal reservoir in relation to thermal groundwater in the Bugok area, southern Korea, in order to assess the potential use of geothermal energy in South Korea. Thermal water at Bugok has been exploited down to about 400 m below the land surface and shows the highest outflow temperatures (up to $78{\circ}C$) in South Korea. Based on the hydrochemical data and occurrence, groundwater in Bugok can be classified into three groups: $Na-SO_4$ type thermal groundwater (CTGW) occurring in the central part (about 0.24 $km^2$) $Ca-HCO_3$ type cold groundwater (SCGW) occurring in shallow peripheral parts of CTGW; and the intermediate type groundwater (STGW). CTGW waters are typical of thermal water in the area, because they have the highest outflow temperatures and contain very high concentrations of Na, K and $SiO_2$ due to the sufficient reaction with silicate minerals in deep reservoir. Their enriched $SO_4$ was likely formed by gypsum dissolution. The major ion composition of CTGW shows the general approach to a partial equilibrium state with rocks at depth. The application of various alkali ion geothermometers yields temperature estimates in the range of 88 to $198{\circ}C$ for the thermal reservoir. Multiple mineral equilibrium calculation indicates asimilar but narrower temperature range between about 100 and $155{\circ}C$. These temperature estimates are not significantly higher than the measured outflow temperatures for CTGW Considering the heat loss during the ascent- of thermal waters, this fact may suggest that a thermal reservoir in the study area is likely located at relatively shallow depths (possibly close to the depth of preexisting wells). Therefore, we suggest a high potential for geothermal energy development around the Bugok area in southern Korea.