• Proceedings of the Korean Society of Laser Processing Conference
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• 2004.10a
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• pp.22-28
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• 2004

Pit and rim formation on the Acrylonitrile Butadiene Styrene(ABS) plastic surface was evaluated after it was irradiated by $CO_2$ and Nd:YAG laser beams. Our results show that thermal effect floor was well observed at the outer wall of pit with $CO_2$ laser irradiated while it was not the case with Nd:YAG laser irradiated. Also the volume and depth of pit formation increase proportionally with the energy intensities of two laser irradiations, but there are significant differences in the slope, width, and FWHM of the Pit formation with two types of laser irradiations. This result shows that $CO_2$ laser irradiation leads to better cooling contraction effect while Nd:YAG laser irradiation induces better recoil pressure effect during the interaction between ABS plastic and laser beam irradiation. The shape of the laser marking could vary significantly depending on the traveling path of molten plastic during injection molding of ABS plastic. Therefore, the selection of material and molding process can have a great impact on the performance of optical storage media.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.273-276
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• 2003

High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that can not be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. Bi2223 high-temperature superconductivity have a single filament drawing process, and multi-filament drawing process. This study analysed multi-filament drawing process by FEM, a defects during multi-filament drawing was studied by FEM.

• Transactions of Materials Processing
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• v.13 no.1
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• pp.78-83
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• 2004

High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that cannot be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. And by these properties, Bi2223 high-temperature superconductor, which has a single filament drawing process and multi-filament drawing process, has a defect like sausaging and bursting at a center. This study analyzed multi-filament drawing process by FEM, and a defect generated during multi-filament drawing was studied by FEH. Specially, in order to prevent a bursting at a center, this study presented a method that inserts a pure Ag at a center of multi-filament wire

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.1023-1031
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• 2010

With recent advances in hardware and wireless communication techniques, wireless multimedia sensor network which collects multimedia data through wireless sensor network has started to receive a lot of attentions from many researchers. Wireless multimedia sensor network requires a research of efficient compression and transmission to process the multimedia data which has large size, in the wireless sensor network that has very low network bandwidth. In this paper, we propose PIT protocol for the transmission based on the priority that classified by the DPCM compression. The PIT protocol sets different priority to the each subbands which are divided by the wavelet transform. The PIT protocol transmits the data with higher priority to guarantee the high image quality. The PIT protocol uses the characteristic of wavelet transform that the transformed image is very insensible to the data loss. In PIT protocol, each subbands of wavelet transformed image has fair weight in the compressed image to utilize the prioriy based transmission. The experiment results show that the PIT protocol improves the quality of image in spite of data loss.

• Animal Bioscience
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• v.35 no.12
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• pp.1977-1985
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• 2022

Objective: This study was conducted to determine the seasonal characteristics of odorous material emissions from a swine finishing barn equipped with a continuous pit recirculation system (CPRS) using aerobically treated manure. Methods: The CPRS consists of an aerobic manure treatment process and a pit recirculation system, where the solid fraction is separated and composted. The aerated liquid fraction (290.0%±21.0% per day of total stored pig slurry) is continuously recirculated to the top of the slurry in the pit. Four confinement pig barns in three piggery farms were used: two were equipped with CPRS, and the other two operated a slurry pit under the slatted floor across all seasons. Results: The indoor, exhaust, and outside odor intensities were significantly lower in the CPRS group than in the control group (p<0.001). In the CPRS group, the odor intensity outside was significantly lower in the fall than in the other seasons (p = 0.015). In the indoor atmosphere, the temperature and CO₂, NH₃, and H₂S contents of the CPRS group were significantly lower than those of the control group (p<0.05). In the CPRS group, indoor temperature did not significantly change in the spring, summer, and fall seasons and was significantly lower in the winter (p = 0.002). NH₃, H₂S, methyl mercaptan, dimethyl disulfide, trimethylamine, phenol, indole, and skatole levels were significantly lower in the CPRS group than in the control group (p<0.05). There were significant seasonal differences on the odorous material in both the control and CPRS groups (p<0.05), but the pattern was not clear across seasons. Conclusion: The CPRS can reduce the indoor temperature in the summer to a level similar to that in the spring and fall seasons. The CPRS with aerated liquid manure is expected to reduce and maintain malodorous emissions within acceptable limits in swine facilities.

• Progress in Superconductivity
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• v.3 no.2
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• pp.213-217
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• 2002

We have fabricated successfully single-filament composite $MgB_2$/SUS tapes, as an ultrarobust conductor type. The fabrication of the $MgB_2$/SUS tapes was performed by power-in-tube (PIT) process such as swaging and cold rolling. The critical transition temperatures $T_{c}$~38.5 K and ~36 K were observed for the sintered and the nonsintered $MgB_2$/SUS tapes, respectively In addition, the isothermal magnetization M(H) of the sintered $MgB_2$/SUS tapes was measured at temperatures T (between 5 and 50 K) in fields up to 6 T, employing a PPMS-9 (Quantum Design). The persistent current density (J$T_{P}$) values were obtained from the M(H) data, using Bean model, fur the sintered $MgB_2$/SUS tapes. The estimated values were higher than ~ 6$\times$ $10^{5}$ $A/\textrm{cm}^2$ at T = 5 K, with H : 0 G. We also investigated the cross section of the sintered tapes, by using SEM and EDX. An evidence of weak reaction on boundary between $MgB_2$ and SUS tube is found in the SEM and EDX.X.X.X.

• Corrosion Science and Technology
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• v.3 no.3
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• pp.102-106
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• 2004

Al foil used was 99.9 and 99.99 %. Test solution used was NaCl solution. The noise was determined using controlled potential electrolysis at -200 and -700 mV vs. NHE. The current fluctuation was caused by breakdown and repaired process of aluminum oxide film. The current fluctuation value of noise was proportion to degree of growth. The number of noise was proportion to the number of pit. The examining of current flutulation value and number of noise could be evaluated corrosion. A 99.99 % Al foil was the mostly crystal of {100} plane, and showed three-dimensional, as azimuth pit with along the direction of this place piled up. A 99.9 % Al foil was polycrystal, and in order of (311) >(222) >(200) >(111) plane. The azimuth pit did not occurred as the dissolution was occurred from each plane.

• Korean Journal of Optics and Photonics
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• v.4 no.4
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• pp.403-410
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• 1993

The scalar diffraction theory of the read-out signal in optical disc is described. and numerical results is given. The strength of this signal depends on the shape of bump(pit) which show more or less rounding of the edge because of the photoresist process. It is shown that the ideal shape is the retangular form, with no rounding of edge. This form is not achievable in practise. but the results show that very satisfactory values of the read-out signal can nevertheless be achieved in the presence of the moderate amounts of rounding.unding.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1211-1212
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• 2006

The electrophoretic deposition process of Ni nano-particles was employed for self-repairing of heat exchanger tubes. For electrophoretic deposition of Ni nano-particles on pitted Ni alloy specimen, a constant electric field of 100 V $cm^{-1}$ was applied to the specimen for 180 s in Ni-dispersed solution. It was found that as electrophoretic deposition proceeded, the size of the pit remarkably decreased due to the agglomeration of Ni nano-particles at the pit. This strongly suggests that the electrophoretic mobility of the charged particles is larger for the pit with a higher current value rather than outer surfaces with a lower current value.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.124-131
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• 2004

It is inevitable that corrosion pits have occurred on the marine propeller. If corrosion pits have occurred on the blades, they have been repaired by simple welding methods. It must be that the strength is degraded in this process. In this paper, we analyzed and compared the strength of A1BC3 and HBsCl used for marine propeller after repairing the artificial pit by several different methods.