• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.12
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• pp.674-678
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• 2013

We present a non-invasive technique to the measure temperature distribution in nano-sized porous thin films by means of the two-color laser-induced fluorescence (2-LIF) of rhodamine B. The fluorescence induced by the green line of a mercury lamp with the makeup of optical filters was measured on two separate color bands. They can be selected for their strong difference in the temperature sensitivity of the fluorescence quantum yield. This technique allows for absolute temperature measurements by determining the relative intensities on two adequate spectral bands of the same dye. To measure temperature fields, Silica (SiO2) nanoporous structure with 1-um thickness was constructed on a cover glass, and fluorescent dye was absorbed into these porous thin films. The calibration curves of the fluorescence intensity versus temperature were measured in a temperature range of $10-60^{\circ}C$, and visualization and measurement of the temperature field were performed by taking the intensity distributions from the specimen for the temperature field.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.165-168
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• 2008

This paper presents the design, fabrication and performance of a reinforced concrete beam strengthened by GFRP box plate and its possibility for structural rehabilitations. The load capacity, ductility and failure mode of reinforced concrete structures strengthened by FRP box plate were investigated and compared with traditional FRP plate strengthening method. This is intended to assess the feasibility of using FRP box plate for repair and strengthening of damaged RC beams. A series of four-point bending tests were conducted on RC beams with or without strengthening FRP systems the influence of concrete cover thickness on the performance of overall stiffness of the structure. The parameters obtained by the experimental studies were the stiffness, strength, crack width and pattern, failure mode, respectively. The test yielded complete load-deflection curves from which the increase in load capacity and the failure mode was evaluated.

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.295-299
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• 1998

The magnetic thin films can be prepared without vacuum process and under the low temperature(<100 $^{\circ}C$) by ferrite plating. We have performed ferrite plating of $Ni_xFe_{3-x}O_4$ (x=0.162~0.138) films on cover glass at the substrate temperature 80 $^{\circ}C$ and pH range of the oxidizing solution, 7.1~8.8. the crystal structure of the samples has been identified as a single phase of polycrystal spinel structure by x-ray diffraction technique. The deposition rate and the grain size of the film increased with the pH of oxidizing solution. The coercive force (H_C)$ decreased with the pH of oxidizing solution.

• Environmental Engineering Research
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• v.13 no.3
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• pp.136-140
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• 2008

$TiO_2$ photocatalyst has been known to exhibit a notable disinfecting activity against a broad spectrum of microorganisms. A lot of commercial $TiO_2$ photocatalyst products have been developed for antimicrobial purposes. However, a standard method has not yet been proposed for use in testing antimicrobial activity. In this study, we developed a $TiO_2$ photocatalytic adhesion test method with film as the standard testing method for the evaluation of antimicrobial activity. This method was devised by modifying the previous antimicrobial products test method, which has been widely used, and considering the characteristics of $TiO_2$ photocatalytic reaction. The apparatus for testing the antimicrobial activity was composed of a Black Light Blue (BLB) lamp as UV-A light source, a Petri dish as the cover material, and a polypropylene film as the adhesion film. The standard $TiO_2$ photocatalyst sample, Degussa P25 $TiO_2$ - coated glass, could only be used once. The optimal initial concentration of the microorganism, proper light intensity, and light irradiation time were determined to be $10^6$ CFU/mL, 1.0 mW/$cm^2$, and 3 hr, respectively, for testing and evaluating antimicrobial activity on the $TiO_2$ surface.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.221-225
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• 2009

A solar thermal collector is a solar collector specifically intended to collect heat: that is, to absorb sunlight to provide heat. A flat plate is the most common type of solar thermal collector, and is usually used as a solar hot water panel to generate solar hot water. A flat plate collector consists basically of an insulated metal box with a glass or a plastic cover and a dark-colored copper absorber plate. Solar radiation is absorbed by the copper absorber plate and transferred to water that circulates through the collector in copper tubes. Ultrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to work pieces being held together under pressure to create a solid-state weld. In this study, we developed solar collector ultrasonic welding machine with digital controlled power supply and tested various welding conditions such as welding pressure, welding amplitude, welding speed. Welding speed was considered in 2~12m/min. The width of ultrasonic welds was increased with welding amplitude by 2.2~2.5mm. The fracture load of ultrasonic welds showed 20% higher than domestic products.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.157.1-157.1
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• 2016

In this work, we experimentally investigated the solar absorption performance of Cu-based scalable nanostructured surfaces and compared their performance with the conventional TiNOX. We fabricated Cu-based nanostructured surfaces with a controlled chemical oxidation process applicable to a large area or complex geometry. We optimized the process parameters including the chemical compounds, dipping time and process temperature. We conducted both lab-scale and outdoor experiments to characterize the conversion efficiency of each absorber surfaces with single and double glazing setup. Lab-scale experiment was conducted with $50mm{\times}50mm$ absorber sample with 1-sun condition (1kW/m2) using a solar simulator (PEC-L01) with measuring the temperature at the absorber plate, cover glass, air gap and ambient. From the lab-scale experiment, we obtained ${\sim}91^{\circ}C$ and $94^{\circ}C$ for CuO and TiNOX surfaces after 1 hr of solar illumination at single glazing, respectively. To measure the absorber performance at actual operating condition, outdoor experiment was also conducted using $110mm{\times}110mm$ absorber sample. We measured the solar flux with thermopile detector (919P-040-50). From outdoor experiment, we observed ${\sim}123^{\circ}C$ and $131^{\circ}C$ for CuO and TiNOX with 0.6 kW/m2 insolation at double glazing, respectively. We showed that the suggested nanostructured CuO solar absorber has near-equivalent collection efficiency compared with the state-of-the-art TiNOX surfaces even with much simpler manufacturing process that does not require an expensive equipment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1061-1068
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• 2013

This study predicts distillate productions according to design variables by numerical analysis when the waste heat from a diesel generator is added to the solar-assisted still proposed in a previous study. Mathematical models were set up in reference to previous studies, and the amount of heat exchange from the waste heat recovery pipe was considered. To ensure the reliability of numerical analysis, the result was compared with that of a previous study and then, the distillate productions according to design variables were obtained by the analysis model. The results were found to generally be in agreement, and the increasing amount of distillate production of the still with the added waste heat was confirmed. In addition, the optimal value of the tilt angle of glass cover and the number of cells were determined by numerical analysis.

• Parasites, Hosts and Diseases
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• v.21 no.2
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• pp.187-192
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• 1983

In order to clarify infestation Pattern for the encysted larvae of digenetic trematodes from fresh-water fishes, this survey was carried out from March to September, 1983. A total of 380 fishes of 32 species wore collected with netting at the three reaches, upper, middle and lower in Mangyeong riverside area. After the fishes were dissected into small scraps, they were pressed under cover glass and examined-for the presence of those of digenetic trematodes with a microscope. The resillts obtailled were as follows; Out of a total of 380 knishes inspected, 320 fishes(84%) from 31 species were found positive with, digenetic trematode metacercariae; more than 10 species of the metacercariae Ivere detected in Pseuderasbora parva; .Gnnthepegen mtajimae, Microphysogokio yaluensis, Cultriculus eigenmanni and Gnnthopogon coreanus (more than 8 species) ; Aphyocypris chinensis (8 species) and etc. respectively. Clonorchis sinensis metacercariae were found positive from 93 fishes (25%) from 12 species and detection rates in other species of digenetic trematode metacercariae from various fishes were; Exorchis oviformis, 261 fisles (57%) from 28 species; Cyathocotyle criensalis, 47 fishcs (12%) from 12 species; Metorchis orientalis, 21 fishes (6%) from 12 species; Metagonimus yokogawai, 164 fishes (43%) from 26 species; Pseudesorchis major, 71 fishes (19%) from 18 species; Metacercaria haiegawai, 77 fishes (20%) from 25 species; Centrocestus armatus, 24 fishes (6%) from 7 species; Echinochasmus japonicus, 2 fishes (0.5%) from 2 species, and unidentified species, 34 fishes (9%) from 15 species respectively. The sums of average number of the encysted larvae of all species found in fish body/gram showed 83 in P.parva, Cobitis taenia (74.2), A. chinensis (28.5), Pseudoperilampus uyekii (26.6), G. majimae (19.6) and etc. respectively and the average peak number of each metacercaria in fish body/gram showed 21.7 C. sinensis, 245. ovifcrmis, 15, 3 M, crientalis and 6.1 5. japonicus in P. parva. 42.7 C. orientalis and 25.1 M. yohogawai in C. taenia; 8.3 C. armatus and 8.3 M. hasegawai in P. uyekii. 6.3 P. major in Carassius carassius, and 2.9 unidentified species in G, niajimae respectively.

• Tribology and Lubricants
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• v.32 no.2
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• pp.56-60
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• 2016

Sapphire has a high hardness and strength and chemical stability as a superior material. It is used mainly as a material for a semiconductor as well as LED. Recently, the cover glass industry used by a sapphire is getting a lot of attention. The sapphire substrate is manufactured through ingot sawing, lapping, diamond mechanical polishing (DMP) and chemical mechanical polishing (CMP) process. DMP is an important process to ensure the surface quality of several nm for CMP process as well as to determine the final form accuracy of the substrate. In DMP process, the material removal is achieved by using the mechanical energy of the relative motion to each other in the state that the diamond slurry is disposed between the sapphire substrate and the polishing platen. The polishing platen is one of the most important factors that determine the material removal characteristics in DMP. Especially, it is known that the geometric characteristics of the polishing platen affects the material removal amount and its distribution. This paper investigated the material removal characteristics and the effects of the polishing platen groove in sapphire DMP. The experiments were preliminarily carried out to evaluate the sapphire material removal characteristics according to process parameters such as pressure, relative velocity and so on. In the experiment, the monitoring apparatus was applied to analyze process phenomena in accordance with the processing conditions. From the experimental results, the correlation was analyzed among process parameters, polishing phenomena and the material removal characteristics. The material removal equation based on phenomenological factors could be derived. And the experiment was followed to investigate the effects of platen groove on material removal characteristics.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.2
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• pp.67-73
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• 2010

Unlike Urban building, horticultural facilities has a lot of heat loss through plastic or glass covering material which could be much influential to growing plant and consuming energy for heating greenhouse. In many cases, heat loss from a break of cover, a gap of joint sealing, the entrance to greenhouse and windows for ventilation are the main factors considered in calculating the heating load for horticultural facilities. however the normal observation through human eye and digital camera could not recognize where the heat loss occurred. but the infrared thermal image camera with detecting thermal difference could be very effective for noticing heat loss by analyzing infrared thermal image. In this study, greenhouse structure, covering material, internal and external provisions for Horticultural facilities were surveyed in different sites and Infrared thermal camera shooting and image analysis were performed for auditing heat loss from cultivation facilities The results from this study were that unexpected heat loss had been noticed in 7 representative cases of greenhouse such as side wall covered with single or double plastic, and the joint of horizontal thermal curtain, roof without horizontal thermal curtain, entrance to greenhouse, windows for ventilation. the most important factors for keeping heat energy were whether the horizontal thermal curtain with multifold thermal material was installed or not. The internal or external covering using multifold thermal curtain proved to be the most effective ways to keep heat energy from losing through heat transmission, heat radiation. from inside to outside the horticultural facilities.