• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.91-101
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• 2017

In this study, we conducted the preliminary research for high speed laser cutting of LED module. In particular, the feasibility of ultra-high speed laser cutting of 100 mm/s which exceeds the cutting speed of conventional dicing saw was examined. For this, copper/ceramic and silicone/ceramic hybrid substrates, which are the components of the LED module, were fabricated, and the surface morphology, surface roughness and flexural strength of the laser-cut samples were investigate and compared with the dicing-cut samples. To investigate optimal laser cutting conditions for hybrid substrates, the effects of various laser cutting conditions on cutting surface characteristics were studied using single ceramic and copper substrate. Optimal laser cutting conditions of the hybrid substrates were the use of Ar assist gas, high laser power and high assist gas pressure. Comparing the cutting surface of the hybrid substrates, the surface characteristics of the laser-cut samples are slightly inferior to those of the dicing-cut samples. The average surface roughness of the laser-cut samples was about $9{\mu}m$, and that of the dicing-cut samples was about $4{\mu}m$. However, considering very low cutting speed (3 mm/s) of the dicing saw, the surface morphology of the laser-cut sample was relatively uniform, and the surface roughness was not much different from that of the dicing-cut sample. The flexural strength of the laser-cut samples was equivalent to or slightly inferior to the flexural strength of dicing-cut samples. However, if the laser processing conditions are sufficiently optimized, the ultra-high speed laser cutting of the LED module will be possible.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.205-212
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• 1987

To examine the morphogenetic response, stem segments of 8 Populus spp. and 3 different explants of P. nigra var. italica were cultured on MS (Murashige and Skoog 1962) and WPM (Woody Plant Medium) medium containing various phytohormones. The results obtained were as follows: 1. Shoot regeneration and development from stem segment of 8 Populus spp. showed a quite difference according to the section and the species. All of the species of Leuce and Tacamahaca section did not form adventitious buds, while most of explants showed axillary or dormant bud elongation after 4 weeks. But P. nigra var. italica of Aigeiros section showed a successful adventitious bud formation (mean 5.4 buds per explant). 2. Leaf, petiole, and internode segment of P. nigra var. italica showed a quite differences according to media and ex plants upon the morphogenetic response. Adventitious bud formation from leaf was more abundant and readily initiated on the abaxial side than on the adaxial side. Mean number of 103 adventitious buds per explant was obtained from abaxial side of leaf segment cultured on WPM medium containing $0.2mg/{\ell}$ BAP for 5 weeks. 3. 2,4-D (2,4-dichlorophenoxy acetic acid) supplemented to media appeared to be negative upon the adventitious bud formation of P. nigra var. italica, while it promoted callus formation from all explants. Especially, NAA (${\alpha}$-naphtalene acetic acid) or NAA combination with BAP (6-benzylaminopurine) promoted root regeneration from the all explant of P. nigra var. italica in this study.

• Journal of the Korean Magnetics Society
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• v.26 no.3
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• pp.76-80
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• 2016

CoSiB is the amorphous ferromagnetic material and multilayer consisting of CoSiB and Pd has perpendicular magnetic anisotropic property. PMA has strong advantages for STT-MRAM. Moreover, amorphous materials have two advantages more than crystalline materials: no grain boundary and good thermal stability. Therefore, we studied the magnetic properties of multilayers consisting of the $Co_{75}Si_{15}B_{10}$ with PMA. In this study, we investigated the magnetic property of the [CoSiB (3, 4, 5, and 6) ${\AA}$/Pd(11, 13, 15, 17, 19,and $24{\AA})]_5$ multilayers and found the annealing temperature dependence of the magnetic property. The annealing temperature range is from room temperature to $500^{\circ}C$. The coercivity and the saturation magnetization of the CoSiB/Pd multilayer system have a close association with the annealing temperature. Moreover, the coercivity especially shows a sudden increasing at the specific annealing temperature.

• Food Science and Preservation
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• v.13 no.4
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• pp.465-471
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• 2006

The chemical components of chlorella powder and quality characteristics (texture, color and sensory evaluation etc.) of white bread added with chlorella powder in order to use as a new functional food material of chlorella powder were examined. The proximate composition was composed of crude protein 61.45%, crude fiber 13.47%, nitrogen free extract 13.15%, ash 6.35%, moisture 3.27% and crude fat 2.31%, respectively. The component of major minerals were P (1,478.94 mg%), K (250.54 mg%), Ca (147.24 mg%) and Na (107.26 mg%) and free sugar was composed of maltose 0.12%, glucose 0.09% and fructose 0.08%. The major amino acids of chlorella powder were glutamic acid(4,009.20 mg%), aspartic acid(3,017.72 mg%), proline(3,055.24 mg%), methionine(3,001.52 mg%) and histidine(2,951.06 mg%). The major fatty acids in chlorella powder were composed of linoleic acid and the amounts of those showed 34.27%. The volume tended to increase according to the addition of chlorella powder. Substituting chlorella powder with flour also resulted in decreased lightness, redness and yellowness of the white bread crust The color of white bread crust became darker as the amount of chlorella powder increased. The texture characteristics of white bread containing chlorella powder was no significant difference. The result of sensory evaluation by QDA (quantitative descriptive analysis) showed that overall acceptability of white broads containing 0.2% chlorella powder were higher than that of control without chlorella powder.

• Korean journal of food and cookery science
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• v.3 no.2
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• pp.17-27
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• 1987

The Namul is one of the most popular and fundamental foods in the Korean meal. The taste of NAMUL depends mostly on the seasonings put on which the salt concentration is the prevailing element of them. The purpose of this study is to investigate the optimum salt concentration by sensory evaluation. The amount of each seasoning except salt was reviewed and used following many food preparation books published. Four different concentrations of salt were added to make different salt concentrations of Namuls. The results of the study are following: 1. By reviewing the related publishments, the amount of seasoning used in 300g of cooked Namul were 15.5g of welsh onion, 7.9g of garlic, 9.0g of sesame, and 11.5g of welsh onion, 7.0g of garlic, 6.0g of sesame oil, 3.3g of sesame, 13.9g of sugar, 10.6g of vinegar and 5.6g of red pepper were the main seasonings for 300g of raw Namul. 2. The optimum salt concentration of cooked Nanul was 1.412% and that of raw Namul was 1.368%. 3. The salt concentration had no effect on the texture within the salt concentrations ranges of 0.84% through 1.89% in Platycodon Namul, Radish Namul, Soybean sprouts Namul, Pumpkin Namul, Raw Radish Namlll, Raw Cucumber Namu1. 4. The more the amount of soy sauce increases, the more the palatability drops. Platycodon and Cucumber Namuls had preference of color when the amount of soy sauce added was 0.8%∼l.0% of the Namul. On the other hand, Spinach Namul had the preference up to 4.8% of the Namul. 5. The overall taste of cooked Namul was considered to be the test in the salt concentrations 1.223%∼l.513%, while that of raw Namul was considered to be best in 1.183%∼1.373% of salt concentration. 6. According to the sensory evaluation, there was a tendency that the overall taste of Namul is consistent with the preferance of saltiness in Namul.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.111-120
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• 2016

Wire recognition is one of the important tasks in chip reverse engineering since connectivity comes from wires. Recognized wires are used to recover logical or functional representation of the corresponding circuit. Though manual recognition provides accurate results, it becomes impossible, as the number of wires is more than hundreds of thousands. Wires on a chip usually have specific intensity or color characteristics since they are made of specific materials. This paper proposes two stage wire recognition scheme; image binarization and then the process of determining whether regions in binary image are wires or not. We employ existing techniques for two processes. Since the second process requires the characteristics of wires, the users needs to select the typical wire region in the given image. The histogram characteristic of the selected region is used in calculating histogram similarity between the typical wire region and the other regions. The first experiment is to select the most appropriate binarization scheme for the second process. The second experiment on the second process compares three proposed methods employing histogram similarity of grayscale or HSV color since there have not been proposed any wire recognition method comparable by experiment. The best method shows more than 98% of true positive rate for 25 test examples.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.535-543
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• 2016

This study has been carried out to evaluate the CBR characteristics and the correlations among every soil properties of National road in Yeongnam region. Total of 480 soil samples were collected from 41 administrative districts for more than 30 years. Their physical and mechanical properties such as natural water content, the Atterberg limit, No. 200 sieve passing, the compaction test and the CBR test results were involved. The soils in Yeongnam region, SM, SC, SP and CL by USCS have predominated approximately 79%. The test results show that average CBR values of gravel and sand range from 12.7% to 20.3% and those of silt and clay range from 4.8% to 7.1%. It means that average CBR values of fine grained soils are less than a half of coarse grained one. Natural water content, No. 200 sieve passing, optimum moisture content and maximum dry density of soils are well correlated with CBR values. Especially, it presents that No. 200 sieve passing is the best correlation factor with CBR value. If consider the partition off this region into 6 zones of classified by mother rock, the correlation between CBR value and every soil properties tends to increase. It is suggested that tables, figures and the regressions described in this paper may be available for designers and engineers to understand the characteristics of an embankment materials in Yeongnam region.

• Composites Research
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• v.26 no.1
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• pp.14-20
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• 2013

The electrospun PVDF containing CNT was made for fabricating materials of the actuator. The electrochemical and their actuating movement were evaluated for the actuator performance in the electrochemical environment. The actuator (which was fabricated by electrospinning) had some advantages, i.e., good dispersion and flexible properties. In the electrospinning process, the final product would have different forms based on different essential factors. In this work, electrospun nanofibers were aligned by using the drum-type collector, and the morphology was identified via the field emission-scanning electron microscope (FE-SEM). The uniform dispersion of CNT in PVDF nanofiber was observed by electron probe X-ray micro-analysis (EPMA) test. The results of tensile strength and electrical resistivity provided the aligned state. The electrospun CNT/PVDF nanofiber sheet on the aligned direction showed better mechanical and electrical properties than the case of the vertically-aligned direction. The efficiency and electrical capacities of electrospun CNT/PVDF nanofiber sheets were compared with the cast PVDF sheet for actuator application. Electrospun CNT/PVDF nanofiber sheet exhibited much better the case of actuator performance than cast neat PVDF actuator, due to the excellent electrical connecting areas.

• Journal of the Korean Arthroscopy Society
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• v.10 no.2
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• pp.159-164
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• 2006

Purpose: To evaluate the clinical stability and function after one-stage revision anterior cruciate ligament (ACL) reconstruction using fresh-frozen Achilles tendon allograft Materials and Methods: Thirteen patients who underwent one-stage revision ACL reconstruction using Achilles tendon allograft could be evaluated. The average time from primary procedure to revision surgery was 61.8 months. The mean follow-up period was 38.4 months. The bone defects of pre-constructed femoral and tibial tunnels were filled with calcaneal bone attached to Achilles tendon and the new femoral and tibial tunnels were created. Evaluations included the causes of failure of primary ACL reconstruction, Lysholm knee score, Lachman test, pivot shift test and KT-1000 arthrometer measurement. Results: The most common causes of failure of ACL reconstruction were poor surgical techniques in 10 cases (76.9%). Ten patients (76.9%) were good or excellent on the Lysholm score. Twelve patients (92.3%) had negative or 1+firm end Lachman test. Eleven patients (84.6%) had negative pivot shift test. Nine patients (69.2%) had less than 3 mm difference of manual maximum by KT-1000 arthrometer. Conclusion: One-stage revision ACL reconstruction with fresh-frozen Achilles tendon allograft, creating new tunnels after filling bone defects, resulted in a reliable and predictable outcome in terms of stability.

• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.32-38
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• 1982

This study was carried out to examine the possibility to replace imported wheat flour with taro. Taro and wheat flour were used for the extenders after oven drying($100{\pm}3^{\circ}C$)and pulverized into 80-100mesh minute powder by laboratory willey mill. Urea- and phenol-formaldehyde resin adhesives were used for plywood manufacture, and the extending materials mixed with the extension at the ratio of 10, 20, 30, and 50% to each resin solution. The results obtained at this study were summarized as follows; 1) In dry and wet shear strength of urea-formaldehyde resin adhesive, taro showed very excellent bonding strength compared with wheat flour in all extending ratio. Therefore taro showed the possibility that be usable to taro in place of wheat flour. 2) In dry and wet shear strength of phenol-formaldehyde resin adhesive, in general, wheat flour showed higher bonding strength than taro. But in dry shear strength, taro showed higher shear strength than wheat flour in 30 and 50% extension.