• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.349-358
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• 2004

A low pressure impactor is an impaction device to separate airborne particles into aerodynamic size classes at low pressure condition. We designed a two-stage low-pressure impactor to classify submicron sized environmental aerosols. Performance evaluation was carried out for stages 1 and 2 by using an electrical method. Monodisperse liquid dioctyl sebacate (DOS) particles were generated using evaporation-condensation process followed by electrostatic classification using a DMA (differential mobility analyzer). The test particles were in the range of 0.08∼0.8$\mu\textrm{m}$. For the evaluation of the impactor we used two electrometers; one was connected to the impaction plate of the impactor and the other was to the Faraday cage used as a backup filter. The effect of polydispersity of test aerosols on the performance was investigated. The results showed that the experimental 50-% cutoff diameters at each impactor's operation pressure were 0.53 and 0.187$\mu\textrm{m}$ for stages 1 and stage 2, respectively. The effects of operation pressure on the cutoff diameter and the steepness of collection efficiency curves were also investigated.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1687-1697
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• 2007

Paik Nam-June is known as a Video Artist. Video is a presentation tool with the feature of recordability. However, it is not only a video which has been applied as an art presentation tool by him. Nevertheless, the existing researches fail to notice the aesthetic concept which is shown as the rest contents or forms, as they focus on the media features of Paik Nam-June's video. Therefore, this article aims at contemplating the art world of Paik Nam-June with its contents as 'visualization of music' and its form as 'hypermediacy' Therefore, 1. Sound is shown as the visualization of music, with the direct influence of absolute hollowness and noise of John Cage, originated from Zen Buddhism, while the foundation of it is known to be from the liberation of dissonance of Arnold Schoenberg and creative impromptu of shamanic sound. 2. The from of TVs influence of the orchestra, originated from Culture of a dining table in Korean. and indicated hypermediacy 3. Paik Nam-June indicated 'Text-interpretation' us to text analytics of 'how to read', rather than the question of 'what to tell' by intermedia as the visualization of music & hypermediacy.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1417-1422
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• 2003

An electrical cascade impactor is a multistage impaction device to separate airborne particles into aerodynamic size classes using electrical method. We designed a real-time three-stage electrical low-pressure impactor, which is proper to nanometer sized environmental aerosols. Performance evaluation was carried out for stage 1 and 2. The monodisperse liquid dioctyl sebacate (DOS) particles were generated using condensation-evaporation followed by electrostatic classification using DMA (differential mobility analizer) for particles with diameters in the range of $0.04{\sim}0.8{\mu}m$. The evaluation of the electrical impactor is based on the use of two electrometers, one connected to the impaction plate of the impactor, and the other to the faraday cage as backup filter. The results showed that the experimental 50% cutoff diameters in the operation pressure were 0.53 and $0.12{\mu}m$ for stage 1 and stage 2. The effect of operation pressure on the cutoff diameter and the steepness of collection effcieicy curves is investigated.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.17-23
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• 2016

This study investigates the development of an automatic lightening buoy that can indicate an aquaculture cage at night or in rough weather. The energy for the light is generated by the linear motion of a magnet along with a coil inside the buoy as the waves cause the buoy to oscillate up and down. The principle of the magnet motion is different between the magnet and body of the buoy because the movement of the latter is dependent on the surface wave, while the former is affected by the damper. To obtain a quantitative performance of the buoy, the voltage as well as up and down motion produced by several waves were measured in the wave tank. A shorter wave period, i.e., faster motion, of the magnet produced a brighter light. It is expected that this study can aid in deciding the optimum design of a buoy capable of producing a bright light at any aquaculture site affected by sea or fresh water waves.

• Advances in concrete construction
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• v.2 no.4
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• pp.281-300
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• 2014

This study presents the experimental results of twenty three reinforced concrete beams with rectangular web openings externally strengthened with Fiber Reinforced Polymers (FRP) composites bonded around openings. All tested beams had the same geometry and reinforcement details. At openings locations, the stirrups intercepted the openings were cut during fabrication of reinforcement cage to simulate the condition of inclusion of an opening in an existing beam. Several design parameters are considered including the opening dimensions and location in the shear zone, the wrapping configurations, and the amount and the type of the FRP composites in the vicinity of the openings. The wrapping configurations of FRP included: sheets, strips, U-shape strips, and U-shape strips with bundles of FRP strands placed at the top and sides of the beam forming a fan under the strips to achieve closed wrapping. The effect of these parameters on the failure modes, the ultimate load, and the beam stiffness were investigated. The shear contribution of FRP on the shear capacity of tested beams with web openings was estimated according to ACI Committee 440-08, Canadian Standards S6-06, and Khalifa et al. model and examined against the test results. A modification factor to account for the dimensions of opening chords was applied to the predicted gain in the shear capacity according to ACI 440-08 and CSA S6-06 for bonded Glass Fiber Reinforced Polymers (GFRP) around openings. The analytical results after incorporating the modification factor into the codes guidelines showed good agreement with the test results.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.135-142
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• 2020

The objective of this experiment was to determine the apparent (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in five feed ingredients for male broiler chickens (Ross 308). The test feed ingredients consisted of corn, wheat, soybean meal (SBM), canola meal (CM), and corn distillers dried grains with solubles (DDGS). The birds were fed a standard starter diet for the first 19 d. On day 19, nine hundred sixty birds were assigned to six dietary treatments with eight replicate cages (20 birds/cage) in a randomized complete block design. All experimental diets contained chromic oxide (0.5% in the diet) as an indigestible index. The diets were offered ad libitum for 4 d. At the end of the experiment, all birds were euthanized and ileal digesta samples were collected immediately. The indispensable AA with the least AID and SID were Thr for all the ingredients used in the present study, except for DDGS, in which Lys had the lowest digestibility. For indispensable AA, the AID and SID of Leu, Phe, Arg, and Met were the greatest in corn, DDGS, wheat, SBM, and CM, respectively. The results from the present study showed that there are variations in both the AID and SID of CP and AA among feed ingredients.

• Korean Journal of Poultry Science
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• v.43 no.1
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• pp.21-29
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• 2016

A total of 144 one-day-old male broilers (ROSS ${\times}$ Ross 308) ($42{\pm}0.1g$) were used in a completely randomized design and allotted to one of three dietary treatments to give 6 replicates per treatment (8 birds per cage). The three watery dietary treatments were 1) a corn-soybean meal-based relation [Negative control (NC); no antimicrobial compounds added] with tab water, 2) 8 ppm liquid-alpha-lipoic acid [Positive control (PC)] or 3) 100 ppm liquid-resveratrol. All dietary treatments were continuously provided as a liquid form. Birds were housed in a battery cage (n=48), and were offered liquid dietary treatments at all times. The ambient temperature was maintained at $32{\pm}1^{\circ}C$ for the first 3 weeks and decreased gradually to $28{\pm}1^{\circ}C$ by the end of the experiment (d 35) to induce moderate heat stress. One bird per pen (n=6) was euthanized via cervical dislocation at day 21 to obtain terminal ileum to measure villous height and crypt depth, while another bird per pen (n=6) was similarly euthanized at day 35 and used to harvest breast meat and drumsticks to evaluate meat quality traits. Birds fed liquid-resveratrol did not improve (P>0.05) body weight and average daily gain compared with those fed other dietary treatments from day 1 to day 35. Birds fed liquid-resveratrol had no effect (P>0.05) on villous height compared with birds were in other dietary treatments at day 21. Liquid-resveratrol had no effect (P>0.05) on thiobarbituric acid reactive substance (TBARS) in drumsticks compared with other dietary treatments at day 35. Furthermore, birds fed liquid-resveratrol had no effect (P>0.05) on DPPH radical scavenging activity both in breast meat and drumsticks compared with those fed other dietary treatments at day 35. Morphological changes of ileum were not observed by immunofluorescence, and the level of occludin protein from ileum extracts also did not differ among groups. Our results suggested that liquid form of antioxidant compounds used in the current study such as alpha-lipoic acid (8 ppm) or resveratrol (100 ppm) did not improve growth performance, meat quality traits and histology of terminal ileum compared with those fed negative control in broiler chickens under moderate heat stress for 35 days.

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.161-169
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• 2023

The present study aimed to investigate the effect of Allium hookeri (AH) root on growth performance, serum antioxidant enzyme activity, cecal short-chain fatty acid profiles, and tight junction-related gene expression of broiler chickens. On day 10, 96 birds were allocated to one of two dietary treatments with 6 replicate cages, and 8 birds per cage in a randomized complete block design. The experimental diets consisted of a corn-soybean meal-based control diet and a diet supplemented with 0.3% AH root powder at the expense of the corn in the control diet. The experimental diets were formulated to meet or exceed the nutrients requirements of broilers recommended by Aviagen for each phase (from day 10 to 21 and from day 21 to 28). On day 28, a bird representing the median body weight in each cage was selected, and then blood, cecal digesta, and jejunum tissue samples were collected. No significant differences were observed in body weight gain and feed intake among dietary treatments. However, birds fed the diet containing AH showed a greater gain-to-feed ratio compared to the control group at 21 days of age and throughout the entire experimental period (P<0.05). Serum antioxidant enzyme activity, cecal short-chain fatty acid profiles, and tight junction-related gene expression were not affected by the dietary AH supplementation. Based on the results of the present study, dietary AH supplementation may improve the gain-to-feed ratio, but not gut health markers in broiler chickens from day 10 to 28.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1194-1203
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• 2000

A magnetic field exposure system that generates 60 Hz magnetic fields from 1 mG to 5 G was designed and constructed for small-sized animal study. In order to investigate as many animals as possible at one series of test, uniform magnetic fields are required at wide living area of the animals. In this article, a cubic shaped field exposure system with three animal living floors was designed, which offers about 50 seating capacity. For calculation of magnetic fields inside the cage, a three-dimensional calculation program was developed. Using this, optimum electric current ratio of inner coil to outer coil and position of each coil were determined. Meanwhile, inductance of the exposure system was calculated for the design of power supply. The field measurement results of the manufactured exposure system showed that the difference between maximum and minimum magnetic field at the testing floors was less than 3%, which strongly demonstrated the field exposure system was good for small sized animal study.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1726-1733
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• 2015

In order to study the effect of the high-altitude and dusty weather in northwest of China on the corona characteristics of transmission lines, a corona caged based experimental system with sandy and dusty flow condition is numerically investigated and designed. This system overcomes the difficulties caused by harsh environment and offers easy usage for off-site tests. The design parameters are mainly determined by the characteristics of strong sandstorm in northwest region and test requirements. By the comparison of numerical simulation of the particle diffusion in four programs with rectangular or circular air-duct, a practical technology, which introduces swirl to control the particle diffusion length, is obtained. Accordingly, the structure of round air-duct with swirl elbow in inlet and outlet of high level segment is selected as final program. Systems of control and measurement are designed at the same time. Field tuning results show that the test system could ensure the range of sandy and dusty coverage. The wind speed, sandy and dusty concentration could be controlled and meet the requirements of accuracy. The experimental system has many features, such as simple structure, easy to be assembled, disassembled, transported and operated, small space occupied.