• Journal of the Korean GEO-environmental Society
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• v.12 no.3
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• pp.63-67
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• 2011

Recently, the application of unsaturated-soil theory is concerned in practice. Most characteristics of unsaturated-soil is the relationship between volumetric water contents and matric suction. Usually the volume water contents is estimated by the relationship between gravity water contents and volume water contents because of the difficulty of measurement of volumetric water contents. In this case, the water exists in only void of soil, and the relationship between gravity water contents and volume water contents is calculated by only water in void, but in fact, the water exists in the particle of the soil. So the real volume water contents is different with calculated volume water contents derived by the relationship containing only void water. The object of this research is to revise the relationship between volume water contents and gravity water contents by using the absorptivity tests of the soil particle.

• Journal of the Korea Institute of Building Construction
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• v.14 no.1
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• pp.11-20
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• 2014

This research examined the effect of the quality of aggregate on concrete workability and compressive strength through an investigation into regional aggregate used in domestic ready mixed concrete plants. Through the research, it was found that aggregate for ready mixed concrete shows poor quality overall. The main factor of deterioration in the quality of the concrete is the particle size of fine aggregate and fine particle content in coarse aggregate. The quality of aggregate significantly influences concrete's workability, which is defined based on 0.08mm passage related with powder and absorption. In addition, poor aggregate quality leads to increased water content in concrete to secure workability, which is related with a decline in the compressive strength and durability of concrete.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.198-202
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• 2014

In the solar heat collection system, we can determine how the collector will perform under specific conditions from the efficiency curve. By understanding the basic principles which govern the operation, designers can maximize the output from the collector. Absorptance, transmission and the total heat transfer coefficient were introduced to induce this efficiency curve. Designers who can make use of the implicit information on the curve in this report will generate systems which obtain the best return from their client's investment.

• Agricultural and Biosystems Engineering
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• v.2 no.2
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• pp.75-80
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• 2001

This paper describes method to diagnose abiotic stresses such ad low root temperature, low light intensity and high salinity in cucumber plants with several physiological instruments. The stresses could be detected by measuring and analyzing the differences in chlorophyll content, temperature difference between leaf and atmosphere and light absorptance at wavelengths of 480, 560, 710, 1420 and 1650nm. It was concluded that the stresses could be first diagnosed from the 3rd to 10th day after treatment and the overall accuracy of diagnosis was estimated between 25 and 75%. near-infrared spectrometer showed better and earlier detection than the other instruments investigated.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.437-439
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• 2007

This paper was analyzed the resistivity change characteristic of mortar model block and concrete that was made earth electrode that's used concrete or basic concrete of building for 1 year. The early resistivity measurement value of concrete model block is higher than mortar model block. But after 1 year the resistivity measurement value of mortar model block is significantly higher than concrete model block. Because depends on time elapsed complete dryness factor of mortar model block that has not gravel is higher than concrete model block. And absorptance and function of mortar mode block was by far outstanding than concrete model block in the data for verification of the amount of contained water and the amount of dryness of mortar model block and concrete model block.

• Solar Energy
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• v.2 no.2
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• pp.1-9
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• 1982

This paper presents a method. for estimating the useful output of solar heating sys-terns. Heating load calculations, climatic data and various conditions are used in this procedure to estimate the fraction of the monthly heating load supplied by solar energy for a particular system the design procedure presented in this paper referred to the f-chart method. The results of this study are as follows; 1) The collected energy is not rised lineary to collector area. 2) If the heating area has equivalent solar collector area, the solar energy utilization for space heating is over 90%. 3) Transmittance- absorptance product for radiation at normal incidence, (${\tau}{\alpha}$)/(${\tau}{\alpha}$)n, during most of the heating season is 0.92 for a two-cover collector. 4) Orientation of the collector has little effect on the annual performance of solar heating system within the $15^{\circ}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.464-467
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• 2004

An uncooled infrared sensor has been prepared with sputtering, plasma ash, ICP, and PECVD on a Si wafer In order to analyze the resistance characteristics with the bridge length in the infrared sensor, three samples were prepared with lengths of 0 (no bridge), 15 (short bridge), and 29 urn (long bridge), respectively. I-V curves were measured for their resistance characteristics and EPMA for the dopping concentration of the amorphous Si. The phosphorus concentration was about 4 % and the resistance was increased with the bridge length. The bridge length of cantilever is very important factor for improvement of the efficiency in an infrared sensor.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.57-64
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• 2006

Cr-CrO cermet solar selective coatings with a double cermets layer film structure were prepared using a special direct current (dc) magnetron sputtering technology. The typical films structures from surface to bottom substrate were measured to be an $Al_2O_3$ anti-reflection layer on a double Cr-CrO cermet layer on an Al metal infrared reflection layer. Optical properties of optimized Cr-CrO cermet solar selective coating were absorptance (${\alpha}$) = 0.95 and emittance (${\varepsilon}$) = 0.10 ($100^{\circ}C$). Atomic force microscopy (AFM) image showed that Cr-CrO cermet film was very smooth and their grain size was also very small The results of thermal stability test showed that the Cr-CrO cermet solar selective coatings were stable for use at temperature of $400^{\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.4
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• pp.185-191
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• 2010

To effectively utilize resources of reject ash and dredged soil, globular shape-formed artificial lightweight aggregate were manufactured in 8~10 mm size. Starting materials were changed various grading and composition, sintered at $1050{\sim}1250^{\circ}C$. The specific gravity, water absorptance of artificial lightweight aggregates were measured on the basis of the KS. In this study could make a prediction about application of bloating mechanism by ferrous materials and alkali/alkali-earth oxide at high temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.391-392
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• 2008

A surface micromachined uncooled microbolometer based on the amorphous silicon was designed and fabricated. We designed the microbolometer with a pixel size of $35\times35$, $44\times44{\mu}m^2$ and a fill factor of about 70 % by considering such important factors as the thermal conductance, thermal time constant, the temperature coefficient of resistance, and device resistance. Finally, we successfully fabricated the microbolometer by using surface MEMS technology, and the properties of bolometer have been measured as such that TCR and absorptance can be achieved above -2.5%/K and about 90% with titanium layer, respectively.