• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.220-220
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• 2009

In case of favourable irradiation conditions, the ratio of irradiation to the total irradiation went up and then the irradiation increased in the area with high angle of inclination. The study showed that on a clear day with the irradiation of more than $800[W/m^2]$, the pattern of alternating current power change in the fixed system was similar with that in the single-axis tracker. On the contrary, in case of unfavourable irradiation conditions, the ratio of diffuse irradiation to the total irradiation went up and then the horizontal irradiation increased. In the demo system, the fixed system, the single-axis tracker and the dual-axis tracker all had low generation power and similar generation pattern with each other. The study showed the generation power varied with the irradiation in the fixed system, while in the single-axis tracker and the dual-axis tracker, the amount of the generation power variation was much more than the irradiation variation. The demo system was operated from 11:00 AM to 2:00 PM for generating power, during which time, 46[%] to 56[%] of the total generation power was produced. In this study. the generation power was increased by 147[%] in the fixed system, by 136[%] in the single-axis tracker, and by 164[%] in the dual-axis tracker, and the pattern of generation power was similar with the generation power variation in the situation where the irradiation increased by 140[%] in the spring with plenty of insolation. The alternating current power was more sensitive to variation of the irradiation than to that of the surface temperature of a module. The variation of the irradiation had a more positive effect on the generation power than the type of array.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.732-738
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• 2005

The purpose of this study is the presentation of the proper microwave treatment conditions by means of the investigation of the effect of microwave irradiation on the dewaterability and dryability of sludge. For the improving of dewatering efficiency of sludge using the microwave, the proper time of microwave irradiation is very important. The dewatering efficiency of thickening sludge conditioned by microwave irradiation for proper time was considerably improved with reducing of capillary suction time from 52.3 sec to 30.8 sec, and the sludge conditioned by microwave irradiation had contained the moisture of 81.4% after that pressure filtrationed. The result of drying characteristics of dewatered sludge using the microwave irradiation and furnace heating, for drying of sludge to moisture of below 55%, microwave irradiation time was required 3 min, whereas, furnace heating was required 40 min at $105^{\circ}C$, 20 min at $170^{\circ}C$ and 9 min at $300^{\circ}C$, respectively. We certified that the drying of dewatered sludge using the microwave irradiation was effectively reduction of moisture of sludge compare to traditional heating method.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.660-666
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• 2003

The purpose of this study was to investigate the inhibitory effect of Er:YAG laser against the intraoral acid producing bacterium of S. mutans. Bacterial pellet containing S. mutans KCTC 3065 was irradiated by Er:YAG laser having a $650\;{\mu}m$ diameter beam by non-contact mode. Irradiated parameters were 50mJ, 10Hz and exposure time were 1s, 3s, 5s, 7s, 9s respectively. We obtained the following results of relative growth rate and acid-producing ability of S. mutans by culturing for 48hrs. 1. The growth rate of S. mutans was decreased in the group of laser irradiation compared to the control group(P<0.01). 2. The growth rate at laser irradiation group of 7s, 9s irradiation time was decreased significantly compared to the laser irradiation group of 1s, 3s, 5s irradiation time, until 12 hours(P<0.05). After 24 hours, all groups of laser irradiation were not found to be statistically different in each other. 3. The acid-producing ability of S. mutans was inhibited for a certain duration by irradiation of laser. In summary, the growth rate and acid producing ability of S. mutans decreased according to laser irradiation. This effect was directly related to the amount of irradiation time. These results suggested that Er:YAG laser had an growth inhibition effect on S. mutans.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.128-131
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• 2003

The effect of microwave irradiation on waste activated sludge was investigated in order to improve solubilization. a different levels of microwave irradiation time were varied within a range from 1 min to 15 min. When WAS was pretreated at 1, 3, 5, 7, and 15 min, the SCOD concentration increased according to microwave irradiation time. A simple batch procedure was used to measure the VFA potential, i.e. the amount of VFA that can be formed through digestion of organic constituent in sludge. At equilibrium point, TVFA in the case of 1, 3, 5, 7 and 15 min microwaved sludges was 8%, 122%, 243%, 279% and 232% higher than that in the case of raw sludge, respectively.

• Tribology and Lubricants
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• v.16 no.4
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• pp.241-246
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• 2000

The effect of post-irradiation shelf-aging time on the wear of UHMWPE was investigated, and wear results were correlated with the time-dependent microstructural changes of polyethylene after gamma irradiation sterilization. The levels of oxidation and crosslinking in the shelf-aged acetabular liners were examined by FTIR and hot xylene extraction, respectively, and uni-directional repeat pass sliding wear tests were conducted by using a pin-on-disc wear tester. Gamma irradiation sterilization in the air environment caused an increase of oxidation, crosslinking, and wear resistance. With aging, however, oxidation progressed and decreased the level of crosslinking. This resulted in a decrease of wear resistance of UHMWPE that was accompanied with white bands and brittle cracking.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.296-302
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• 1999

The effect of post-irradiation shelf-aging time on the wear of orthopaedic grade UHMWPE was investigated, and wear results were correlated with the time-dependent microstructural changes of polyethylene after gamma irradiation sterilization. The levels of oxidation and crosslinking in the shelf-aged acetabular liners were examined by FTIR and hot xylene extraction, respectively, and uni-directional repeat pass sliding wear tests were conducted by using a pin-on-disc wear tester. Gamma irradiation sterilization in the air environment caused an increase of oxidation, crosslinking, and wear resistance. With aging, however, oxidation progressed and decreased the level of crosslinking. This resulted in a decrease of wear resistance of UHMWPE that was accompanied with the existence of white bands and brittle cracking.

• Journal of the Korean Home Economics Association
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• v.30 no.3
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• pp.101-117
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• 1992

Effects of gamma irradiation(2.5∼20kGy) on water absorption property was studied for a local variety of black soybeans. In water absorption patterns of black soybeans, the time to reach a fixed moisture content was reduced depending on the increment of water soaking temperature and irradiation dose. Irradiation at 2.5∼10kGy resulted in the reduction of soaking time of black soybeans by about 1∼3 hours and the increase of hydration capacity by 10∼20%, respectively, compared to the nonirradiated control black soybean. The water uptake rate constant of the irradiated black soybean difinitely increased with the increase of dose levels and water soaking temperature. The activation energy for water absorption and z-value were lower in the irradiated black soybeans than in the nonirradiated control black soybean. The efficacy of water absorption property in the irradiated black soybeans was also recognized after one year of storage at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.22-23
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• 2006

Proton irradiation technology was used for improvement of switching characteristics of the PT-IGBT. Proton irradiation was carried out at 5.56 MeV energy with $1{\times}10^{12}/cm^2$ doze from the back side of the wafer. Characterization of the device was performed by I-V, breakdown voltage, threshold voltage, and turn-off delay time measurement. For irradiated device by 5.56 MeV energy, the breakdown voltage and the threshold voltage were 730 V and 6.5~6.6 V, respectively. The turn-off time has been reduced to 170 ns, which was original $6\;{\mu}s$ for the un-irradiated device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.302-306
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• 2019

We investigated a solution-derived $Y_2O_3$ film treated by ion beam (IB) irradiation as a liquid crystal (LC) alignment layer. With IB irradiation, homogeneous LC alignment was achieved irrespective of the annealing temperature. To verify the effect of IB irradiation, we conducted surface analyses such as X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). As $Y_2O_3$ is a high-k material, the electro-optical properties of the twisted nematic (TN) cells were superior to those of conventional TN cells based on a rubbed polymer, with an LC rising time of 4.1ms and falling time of 2.9ms. The IB-irradiated $Y_2O_3$ is a good alternative as an alignment layer for fast-switching TN LC displays.

• Journal of the Korean institute of surface engineering
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• v.57 no.4
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• pp.331-337
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• 2024

Platinum has been utilized as an excellent electrocatalyst with low overpotential for the hydrogen evolution reaction (HER) in water splitting, despite of its high cost. In this study, platinum particles were produced using pulsed laser technology as a HER catalyst for water splitting. The colloidal platinum particles were synthesized by nanosecond pulsed laser irradiation (PLI) without reducing agents, not traditional polyol processes including reducing agents. The crystal structure, shape and size of the synthesized platinum particles as a function of pulsed laser irradiation time were investigated by XRD and SEM analysis. Additionally, the electrochemical properties for the HER in water splitting of the irradiation time-dependent platinum electrocatalysts were studied with the analysis of overpotentials in linear sweep voltammetry and Tafel slope.