• Journal of the Korean Society for Precision Engineering
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• v.29 no.12
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• pp.1267-1271
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• 2012

Demand for optical glass device used for lighting could increase rapidly because of LED lighting market growth. The optical glass devices that have been formed by hot press molding process the desired optical performance without being subjected to mechanical processing such as curve generation or grinding. EL-Max material has been used for many engineering applications because of their high wear resistance, high compressive strength, corrosion resistant and very good dimensional stability. EL-Max is very useful for a glass lens mold especially at high temperature and pressure. The performance and reliability of optical components are strongly influenced by the surface damage of EL-Max during grinding process. Therefore, the severe process condition optimization shall be necessary for the highly qualified EL-Max glass lens mold. To get the required qualified surface of EL-Max, the selection of type of the diamond wheel is also important. In this paper, we report best grinding conditions of ultra-precision grinding machining. The grinding machining results of the form accuracy and surface roughness have been analyzed by using Form Talysurf and NanoScan.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.2
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• pp.152-163
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• 1990

The purpose of this study is to experimentally analyze the relationship between structural characteristics of cotton fabrics and their cool-and-warm felling in order to develop more comfortable fabrics. Comfort in textile products has been emphasized as consumers preferred performance to fashion of clothing. Thermal comfort of clothing is a basic parameter of the comfort sensation which is usually represented by the cool-and-warm feeling felt by human skin. Cloo-and-warm feeling is perceived by the heat flux which transfers heat energy stored in an object to skin. We feel warm (cool) if the temperature of nerve extremity in skin ascends (descends). As cool-and-warm feeling determines the comfort sensation of clothing, it is important to develop new comfort fabrics. Although considerable works have been made on the body, clothing, and environment, there has been no research study on the structural characteristics of fabrics and their cool and warm feeling. Cool-and-warm feeling is closely related to the transient heat transfer property. This research study used the cotton fabrics manufactured in Korea as sample and measured $q_{max}$ value with thermal property measuring instrument (Thermo-Labo II type). $q_{max}$ values estimated by polynomial regression equation were compared with those observed in this study. This study also identified the structural parameters of cotton fabrics for a specific range of $q_{max}$ values. The findings of this study can be summarized as follows: 1) As the thickness, porosity and air permeability of cotton fabrics increase, $q_{max}$ value decreases. 2) As the fabric count and over factor of cotton fabrics increase, $q_{max}$ value also increases. 3) $q_{max}$ values have been estimated by simple and polynomial regression equations developed in this study. Regression curves which have been plotted by polynomial regression equations also provided with the range of structural parameters for a specific range of $q_{max}$ values of cotton fabrics. This study would be significant in that it has identified the structural Parameters for the cool-and-warm feeling of cotton fabric at $65\%$ relative humidity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.608-618
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• 1996

Wild perennial types of genus Glycine, as sources of genetic diversity, have been recently employed in the soybean breeding programs. This study was carried out to introduce some useful characters of wild perennial Glycine tomentella into common cultivars, G. max. Parent materials used for interspecific hybridization were three common cultivars, Ulsankong, Baemkong and Danyeobkong, and four G. tomentella strains having different diploid(2n) of 38, 40, 78, and 80. Their cross-fertility, effect of reciprocal cross, development comparison of crossing pod and optimum timing to efficient crossing were investigated. Plant were grown in 1/2,000 Wagner pots in greenhouse and field. Crossing efficiency and pod survival rate were the highest in 2n=38 of the four G. tomentella strains when the common cultivars were fixed as female parents. In the reciprocal cross of three common cultivars and four G. tomentella strains, when the former was used as maternal sources, they showed better crossing rate and longer pod survival than the latter. In the interspecific hybridization between G. max cv. Baemkong andG. tomentella, 2n=38, the pod formed from the female G. tomentella had relatively greater size and weight than that from the female Baemkong in comparison with parents. However, the reverse result was true in a number of ovules per pod. More efficient interspecific hybridization in the field was made on August 20, when temperature and relative humidity were higher and day length was shorter, than one or two months earlier.

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.64-69
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• 2003

Using a high fewer electron beam gun (max. power 20 kW), Gadolinium (Gd, atomic number 64) metal was melted and the temperature distribution of melted surface was measured. With proper optical filters and the adjustment of aperture of lens, the radiation of melted surface was received by a ccd camera and its signal transferred to a computer. The real time monitoring of melted surface with a variation of electron beam Power was Possible and stable operation of electron beam was achieved. It was found that the max. temperature measured by a ccd camera with an assumption of blackbody radiation of melted Gd surface and adaption of Planet's law was above 100~$200^{\circ}C$ compared to that measured by a pyrometer in the same e-beam power.

• The KSFM Journal of Fluid Machinery
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• v.8 no.6 s.33
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• pp.40-46
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• 2005

Because of design and manufacturing costs, it is important to predict an expected life of bellows with component stresses of bellows as its design factors and material characteristics. In this study, numerical analyses are carried out to elucidate the thermal and flow characteristics of the bellows-seal gate and globe valves for high temperature (max. $600^{\circ}C$) and for high pressure (max. $104 kgf/cm^2$) conditions. Using commercial codes, FLUENT, which uses FVM and SIMPLE algorithm, and ANSYS, which uses FEM, the pressure and temperature fields are graphically depicted. In addition, when bellows have an axial displacement, thermal stress affecting bellows life is studied. The pressure and temperature values obtained from the flow analyses are adopted as the boundary conditions for thermal stress analyses. As the result of this study, we got the reasonable coefficients for valve and thermal stress for bellows, compared with existing coefficients and calculated values.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.135-143
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• 2014

The variability and temporal trends of the annual and seasonal minimum and maximum temperature, rainfall, relative humidity, wind speed, sunshine hours, and runoff were analyzed for 5 major rivers in Korea from 1960 to 2010. A simple regression and non-parametric methods (Mann-Kendall test and Sen's estimator) were used in this study. The analysis results show that the minimum temperature ($T_{min}$) had a higher increasing trend than the maximum temperature ($T_{max}$), and the average temperature increased by about $0.03^{\circ}C\;yr.^{-1}$. The relative humidity and wind speed decreased by $0.02%\;yr^{-1}$ and $0.01m\;s^{-1}yr^{-1}$, respectively. With the exception of the Han River basin, the regression analysis and Mann-Kendall and Sen results failed to detect trends for the runoff and rainfall over the study period. Rapid land use changes were linked to the increase in the runoff in the Han River basin. The sensitivity of the evapotranspiration and ultimately the runoff to the meteorological variables was in the order of relative humidity > sunshine duration > wind speed > $T_{max}$ > $T_{min}$. Future studies should investigate the interaction of the variables analyzed herein, and their relative contributions to the runoff trends.

• 한국해양학회지
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• v.18 no.1
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• pp.55-63
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• 1983

The study on the periodic and correlation analysis between water temperature and air temperature has beenconducted by oceanographic data obtained from 1923 to 1979 (For 16-51 years) in 6 ststions in the Korean Waters. The periodic and correlation analyses has been examined by method of he Schuster's and the quadratic formula of least squares method, respectively. The results pbtained from the study are as follows; 1. Periodic analysis 1) The yearly difference between max. and mini. fo surface water temperature was 12.77-17.99$^{\circ}C$ (computed value : 11.67-16.64$^{\circ}C$) in offshore waters, and was 15.72-26.33$^{\circ}C$ (computed value : 15.13-25.29$^{\circ}C$) in inshore waters, and that of air temperature was 21.71-28.60$^{\circ}C$ (computed value : 10.50-27.22$^{\circ}C$). 2) The yearly mean of water temperature by station was 11.25-18.78$^{\circ}C$, and that of air temperature was 11.39-16.16$^{\circ}C$. 3) The annual compnent amplitrde of water temperature was 5.72-12.54$^{\circ}C$, and that of air temperature was 10.04-13.49$^{\circ}C$. 4) The semi-annual component amplitude of water temperature was 0.83-1.30$^{\circ}C$, and that of air temperature was 0.72-1.26$^{\circ}C$. 5) The annual component phase of water temperature was 215-228$^{\circ}C$ (max. temperature shall be in the first and in the middle ten days of August) in inshore waters and 138-244$^{\circ}C$ (max. temperature shall be in the first and in the middle ten days of August) in offshore waters, and that of air temperarture was 212-221$^{\circ}C$ (max. temperature shall be in the first and in the middle ten days of July and in the first tin days of August). 6) The semi-annual component phase of water temperature was 87-110$^{\circ}C$ in offshore waters, and 167-212$^{\circ}C$ in inshore waters, and that of air temperature was 156-189$^{\circ}C$. 2. Correlation analyses of water temperature and air temperature before one month. 1) When the water temperature is in rising time, the quadratic constant of correlation formual was the gradual inreasing type ( constant; 0.010-0.026) in offshore waters, and the gradual decreasing or proportional type (constant; -0.020-0.001) in inshore waters. 2) when the water temperature is in descending time, the quadratic constant of correlation formula was the gradual increasing type (constant: 0.012-0.021) 3) the determination coefficient was 0.964-0.992 at rising time and 0.982-0.999 at descending time of water temperature.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1115-1129
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• 2016

To analyze human thermal environments in protected horticultural houses (plastic houses), human thermal sensations estimated using measured microclimatic data (air temperature, humidity, wind speed, and solar and terrestrial radiation) were compared between an outdoor area and two indoor plastic houses, a polyethylene (PE) house and a polycarbonate (PC) house. Measurements were carried out during the daytime in autumn, a transient season that exhibits human thermal environments ranging from neutral to very hot. The mean air temperature and absolute humidity of the houses were $14.6-16.8^{\circ}C$ (max. 22. $3^{\circ}C$) and $7.0-12.0g{\cdot}m^{-3}$ higher than those of the outdoor area, respectively. Solar (K) and terrestrial (L) radiation were compared directionally from the sky hemisphere (${\downarrow}$) and the ground hemisphere (${\uparrow}$). The mean $K{\downarrow}$ and $K{\uparrow}$ values for the houses were respectively $232.5-367.8W{\cdot}m^{-2}$ and $44.9-55.7W;{\cdot}m^{-2}$ lower than those in the outdoor area; the mean $L{\downarrow}$ and $L{\uparrow}$ values were respectively $150.4-182.3W{\cdot}m^{-2}$ and $30.5-33.9W{\cdot}m^{-2}$ higher than those in the outdoor area. Thus, L was revealed to be more influential on the greenhouse effect in the houses than K. Consequently, mean radiant temperature in the houses was higher than the outdoor area during the daytime from 10:45 to 14:15. As a result, mean human thermal sensation values in the PMV, PET, and UTCI of the houses were respectively $3.2-3.4^{\circ}C$ (max. $4.7^{\circ}C$), $15.2-16.4^{\circ}C$ (max. $23.7^{\circ}C$) and $13.6-15.4^{\circ}C$ (max. $22.3^{\circ}C$) higher than those in the outdoor area. The heat stress levels that were influenced by human thermal sensation were much higher in the houses (between hot and very hot) than in the outdoor (between neutral and warm). Further, the microclimatic component that most affected the human thermal sensation in the houses was air temperature that was primarily influenced by $L{\downarrow}$. Therefore, workers in the plastic houses could experience strong heat stresses, equal to hot or higher, when air temperature rose over $22^{\circ}C$ on clear autumn days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.444-450
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• 1995

It was very hard to gather the seeds of Eleutherococcus senticosus Max. known as a medicinal plant for they tend to drop under the high temperature condition during the summer period in Korea. Therefore, this study was conducted to select seed production site for Eleutherococcus senticosus in Korea, comparing the climate of Hokkaido of Japan, in which the seeds have been produced, with that of various place in this country. It was low that the average maximum temperature during the hottest summer two months (July and August) as a 24.4$^{\circ}C$ in Hokkaido and 21.2$^{\circ}C$ in Daegwanryeong compared with 27.4$^{\circ}C$ in Changsu. Especially in Daegwanryeong, average maximum temperature from June to September remained as low as 21$^{\circ}C$. Effective accumulated temperature(>5$^{\circ}C$) was 807$^{\circ}C$ in Hokkaido and 964$^{\circ}C$ in Daegwanryeong during the ripening period. Monthly sunshined hours from July to August were 121.7~128 hours in Daegwanryeong and 83.5~85.4 hours in Hokkaido. The Eleutherococcus senticosus sprouts at 8.5$^{\circ}C$, comes to flowering season in mid-August, and ripens during late-August and October in Hokkaido, the climate of which is similar to that of Daegwanryeong.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.167-173
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• 2002

The look up table method conventionally applied to control the inner temperature and humidity of a laver drying machine has repeatedly occurred not only laver's damage but also inferior goods since the reaching time at the optimum state takes a long time. In this paper, a fuzzy control theory instead of the look up table was proposed to reduce the reaching time at the optimum state. The proposed method used six input variables and four output variables for the fuzzy control, and a triangle rule for a fuzzifier, The Mandani's min-max method was applied to a fuzzy inference. Also, the mean method of maximum was applied to a defuzzifier. The method applied to the fuzzy controller contributed to reduce the reaching time at the optimum state, and to minimize not only laver's damage but also inferior goods.