• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.91-91
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• 2004

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.270.1-270.1
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• 2000

• Bulletin of the Korean Space Science Society
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• 2000.10a
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• pp.75-75
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• 2000

No Abstract, See Full Text

• Korean Journal of Materials Research
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• v.2 no.4
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• pp.270-278
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• 1992

The effect of Ni-rich phase on the stress-rupture properties of Ni mlcroalloyed W were studied using direct load creep tester at 100$0^{\circ}C$, 110$0^{\circ}C$, and 120$0^{\circ}C$ in $H_2.$ The stress rupture strength of 100hrs. of W-0.4wt% Ni was 43% higher at 100$0^{\circ}C$ and 35% higher at 110 $0^{\circ}C$than that of W-0.2wt% Ni due to the larger initial grain size, the higher relative density and the higher grain growth during test. That of W-0.8wt% Ni was 90% higher at 100$0^{\circ}C$ and 60% higher at 110$0^{\circ}C$ than that of W-0.2wt% Ni. The activation energy of W-0.4wt% Ni for creep was 81.3 Kcal/mole. It was considered that creep deformation was controlled by the diffusion of W in the Ni rich phase between the grains and the deformation of grains. All of the specimens showed intergranular fracture by grain boundary cavitation and growth of cavity throughout the entire spcimen cross-section.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.637-647
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• 2010

This paper suggested an algorithm that uses a multiplier, 'w bit $\times$ w bit = 2w bit', to process $\frac{N}{D}$ integer division of 2w bit integer N and w bit integer D. An algorithm suggested of the research, when the divisor D is '$D=0.d{\times}2^L$, 0.5 < 0.d < 1.0', approximate value of $\frac{1}{D}$, '$1.g{\times}2^{-L}$', which satisfies '$0.d{\times}1.g=1+e$, e < $2^{-w}$', is defined as over reciprocal number and the dividend N is segmented in small word more than 'w-3' bit, and partial quotient is calculated by multiplying over reciprocal number in each segmented word, and quotient of double precision integer division is evaluated with sum of partial quotient. The algorithm suggested in this paper doesn't require additional correction, because it can calculate correct reciprocal number. In addition, this algorithm uses only multiplier, so additional hardware for division is not required to implement microprocessor. Also, it shows faster speed than the conventional SRT algorithm. In conclusion, results from this study could be used widely for implementation SOC(System on Chip) and etc. which has been restricted to microprocessor and size of the hardware.

• IMMUNE NETWORK
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• v.2 no.3
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• pp.158-165
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• 2002

Background: Toluene diisocyanate (TDI) can cause contact allergy and occupational asthma, but the mechanism underlying sensitization to this chemical compound remains controversal. Also the correlation of mast cell with contact hypersensitivity (CHS) and the role of mast cell in the TDI-induced CHS is unknown. This issue was investigated by administrating TDI on the skin of genetically mast cell-deficient WBB6F1/$J-Kit^{W}/Kit^{W-v}$ ($W/W^{V}$) and congenic normal WBB6F1/J-Kit+/+ (+/+) mice. Methods: To development of animal model of TDI-induced CHS and to investigate the correlation of mast cell with CHS and the role of mast cell in the TDI-induced CHS, $W/W^V$ and +/+ mice were sensitized with TDI on the back skin at day 1 and day 8, and then challenged with 1% TDI on the ear at day 15. At 1, 2, 4, 8, and 24 hours after 1% TDI challenge, the ear thicknesses were measured. It was investigated the histologic changes of dermis in the ear of $W/W^V$ and +/+ mice at 24 hours after 1% TDI challenge. Results: TDI induced a significant ear swelling response in $W/W^V$ and +/+ mice. TDI induced the significant infiltrations of polymorphonuclear leukocytes and eosinophils in $W/W^V$ and +/+ mice, but not of mast cells in normal mice. And TDI increased a characteristic extent of mast cell degranulation in normal mice. There were no significant differences in the ear swelling and the infiltrations of polymorphonuclear leukocytes and eosinophils of normal versus $W/W^V$ mice, either at baseline or after TDI-induced CHS. Conclusion: From the above results, TDI can be used as a murine CHS model, and the mast cells may not be essential in TDI-induced CHS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.207-214
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• 2016

This study determined the effect of Lespedeza Caneata extract on the livers and kidneys of lead-administered mice. The experimental groups were divided into a normal group, Pb 4W group, Pb-LC 4W group, Pb 8W group, and Pb-LC 8W group. The normal group was supplied single distilled water, and the pb group was provided distilled water in which lead acetate was dissolved at 1,000 ppm. The Pb-LC group was provided with lead as drinking water, and the Lespedeza Caneata was orally medicated at a concentration of 500 mg/kg daily. AST, ALT, and BUN enzyme activities and histological experiments on the livers and kidneys resulted in the following conclusions. AST, ALT, and BUN activities increased in the experimental group compared to the normal group and decreased more in the Pb-LC group than the pb group during the same period. The histological results reveal that portions of the livers and kidneys were deformed in the Pb 4W group, and most of the Pb 8W group experienced necrosis and deformation. pb-LC4W and Pb-LC 8W groups experienced less deformation than the Pb 4W and Pb 8W groups. During the same period, the Pb-LC group experienced less histological changes than the Pb group. These results suggest that Lespedeza Caneata extract may have some protective effect on hepatic tissue and renal tissue damage with lead-administered in mice.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.447-455
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• 2005

The purpose of this study was to examine the effect of Nd:YAG laser irradiation for sensory nerve conduction change. Nd:YAG laser was irradiated to mental region for 5 minutes with the parameters that 10 Hz and 20 Hz of 100 mJ/pulse. Target size of irradiation was 30 mm diameter of circle and target-tip distance was about 10 mm. Therefore, the power density were 212 $mW/cm^2$ and 424 $mW/cm^2$. Sensory nerve conduction was evaluated with $Neurometer^{\circled}$ CPT/C before and after Nd:YAG laser irradiation. As an outcomes, the current perception threshold(CPT) and pain tolerance threshold(PTT) were obtained. We made a comparison of these two values and the results were as follows. 1. There was no significant difference in CPT at 1W, 10 Hz and 2 W, 20 Hz Nd:YAG laser irradiation. 2. There was no significant difference in PTT at 10 Hz, 20 Hz of 100 mJ/pulse Nd:YAG laser. 3. There were no significant differences in CPT and PTT between 1 W, 10 Hz group and 2 W, 20 Hz group. Therefore, We can make a conclusion that Nd:YAG laser irradiation to mental region have no effect on mental nerve conduction in our study model.

• Korean Journal of Materials Research
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• v.10 no.3
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• pp.218-222
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• 2000

W-Ti film properties for X-ray absorber applications have been investigated with Ti composition have been investigated with Ti composition variation. W-Ti films were deposited by DC magnetron sputtering system. As the working pressure increases, film density decreases and film stress changes from compressive to tensile. The transition pressure (where the film stress in zero) and the stress gradient decrease by adding Ti into W-Ti(6.5 at.%) film shows the smallest stress gradient and transition pressure. It also shows high density ($17.7g/\textrm{cm}^3$) similar to that of pure-W ($17.8g/\textrm{cm}^3$) at the transition pressure. All the films show columnar structure, and its size decreases with increasing Ti composition. Surface roughness and thermal stability are improved by Ti-addition, resulting in a better property for X-ray absorber applications.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.333-340
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• 2016

An alkaline protease was purified and characterized from an alkalophilic microorganism, Bacillus sp. DK1122, isolated from soil in central Korea. The optimum temperature and pH for the growth of the producer strain were 40℃ and pH 9.0, respectively. The protease was produced aerobically at 40℃ after 24 h incubation in modified Horikoshi I medium (pH 9.0) containing 0.5% (w/v) glucose, 0.8% (w/v) yeast extract, 0.5% (w/v) polypeptone, 0.1% (w/v) K₂HPO₄, 0.02% (w/v) MgSO₄·7H₂O, 1% (w/v) Na₂CO₃, and 3% (w/v) NaCl. The alkaline protease was purified by 70% ammonium sulfate precipitation of the culture supernatant of Bacillus sp. DK1122, followed by CM-Sepharose chromatography. The molecular weight of the enzyme was estimated to be 27 kDa on the basis of SDS-PAGE. The optimum temperature and pH for the protease activity were 60℃ and pH 9.0, respectively. Addition of CaCl₂ increased the thermal stability of the purified protease, where 90% of protease activity was retained at 60℃ for up to 3 h. Consequently, it is expected that the alkaline protease from this study, exhibiting stability at pH 7–9 and 60℃, may be promising for application in the food and detergent industries.