• Korean Journal of Materials Research
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• v.12 no.1
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• pp.16-20
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• 2002

In this study, the 95W heavy alloys of 3/7, 5/5 and 7/3 of Ni/Fe ratio were sintered at the temperature range between 1420 and $1480^{\circ}C$ for 1h and their microstructures were discussed for an effect of the ${\mu}$-phase $(Fe_7W_6)$ on the microstructure. The ${\mu}$-phase was observed in the only 95W-1.5Ni-3.5Fe alloy of 3/7 and it is thought to be formed and grown from the surface of the W particle. The W particle was surrounded with the ${\mu}$-phase and there were only the W particles and this phase without Ni-Fe-W matrix at the most part. The ${\mu}$-phase changed the interphase structure in the alloy and the grain growth of the W was suppressed because of interrupting the solution-reprecipitation of the W. The W content in the matrix was considered to be lowered due to the interruption of the solution-reprecipitation and the formation of the ${\mu}$-phase in the .

• Journal of Powder Materials
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• v.8 no.4
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• pp.245-252
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• 2001

Recent remarkable progress in the semiconductor industry has promoted smaller size of semiconductor chips and increased amounts of heat generation. So, the demand for a substrate material to meet both the characteristics of thermal expansion coefficient and heat radiation has been on the increase. Under such conditions, tungsten(W)-copper(Cu) has been proposed as materials to meet both of the above characteristics. In the present study, the W-10wt.%Cu powders were synthesised by the mixing and hydrogen reduction of the starting mixture materials such as W-Cu, $W-CuCl_2$and $WO_3-CuCl_2$ in order to obtain the full densification. The W-10wt.%Cu produced by hydrogen reduction showed the higher interparticle friction than the simple mixed W-10wt%Cu because of the W agglomerates. In the dilatometric analysis the W-10wt.%Cu prepared from the $W-CuCl_2$was largely shrank by heating up $1400^{\circ}C$ at the constant heating rate of $5^{\circ}C$/min. The possibility of application of metal injection molding (MIM) was also investigated for mass production of the complex shaped W-Cu parts in semiconductor devices. The relationship between the temperature of molding die and the pressure of injection molding was analyzed and the heating up stage of 120-$290^{\circ}C$ in the debinding process was controlled for the most suitable MIM condition.

• Food Science and Preservation
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• v.17 no.5
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• pp.741-751
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• 2010

We evaluated the nutritional value of a Monascus pilosus mycelial ethanolic extract (MEM) and culture filtrate (CFM) by determining the contents of monacolin K and citrinin, and by measuring antioxidant and antimicrobial activities. The yields of freeze-dried MEM and CFM powder were 4.02% and 3.35% of wet weight, respectively. Pigment content ($OD_{500}$ value) of MEM (0.79) and CFM (0.63) were lower than those of commercial rice beni-koji ethanolic extracts (EERB) (0.87), but were in good agreement with the L*, a*, and b* values and the hue angles of the products. The total monacolin K content of MEM (24.91 mg%) was higher than those of CFM (1.27 mg%) and EERB (14.65 mg%). However, the active monacolin K content of EERB (5.48 mg%) was higher than those of MEM (3.35 mg%) and CFM (0.4 mg%). Citrinin was not detected in any sample. The total polyphenol content of MEM (4.68%, w/w) was similar to that of CFM (4.29%, w/w), thus 13.75.20.94% higher than that of EERB. The total flavonoid content of EERB was 6.8.7.0-fold higher than those of MEM (0.64%, w/w) and CFM (0.66%, w/w). The total antioxidant capacity of CFM (3.51%, w/w) was 1.62.2.08-fold higher than those of MEM (2.74%, w/w) and EERB (1.69%, w/w). The electron-donating capacities of 1% (w/v) solutions of CFM, MEM, BHT, and EERB were 86.20%, 77.25%, 77.25%, and 44.82%, respectively, and the corresponding reducing powers ($OD_{700}$ values) were 2.1, 2.4, 1.1, and 1.6, respectively. SOD(superoxide dismutase)-like activities were in the order MEM (39.85%) > BHT (37.68%) > EERB (26.70%) > CFM (21.5%). Although the TBARS (% value) of MEM was a little lower than that of BHT, it was higher than those of CFM and EERB. The antibacterial activities of CFM acting on Bacillus brevis and Escherichia coli were somewhat higher than those of MEM, whereas the activities of MEM on Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, and Salmonella enteritidis were higher than those of CFM. However, the antibacterial activities of MEM and CFM were less than those of EERB and BHT. In conclusion, although further studies are needed, we offer experimental evidence that the by-products of M. pilosus MEM and CFM contain significant antioxidant and antimicrobial activities that may be useful in the development of healthy foods.

• Analytical Science and Technology
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• v.7 no.2
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• pp.237-243
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• 1994

The stability of W/O emulsions (milk fat : water=4 : 1, w/w) containing various emulsifiers was compared to determine the effect of different chemical types of emulsifiers in relation to the change of HLB value caused by emulsifier type and the influence of single vs. binary emulsifier systems. These variables were compared at emulsifier HLB values of 0.5~16.7 and at emulsifier concentrations of 1.0~3.0%(w/w). Eleven emulsifiers used as 11 different single mixtures and 16 different binary mixtures were evaluated in W/O type emulsion systems containing 20.0%(w/w) of water in milk fat. This W/O emulsion was stable (more than 90.0 of ESI value) in the range of low value of emulsifier HLB (less than 4.7 of HLB value). All the ESI values of binary emulsifier systems were higher than those of single emulsifier systems. But, the influence pattern of emulsifier HLB on this emulsion stability in single emulsifier systems was very similar to the trend in binary emulsifier systems.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.753-759
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• 1999

The microstructure and electrical properties of ZNR that W $O_3$ is added in the range 0.5~4.0mol%, were investigated. The major part of W $O_3$ were segregated at the nodal point and W-rich phase was formed. Three crystalline phases, such as W-rich phase (W $O_3$), Bi-rich phase (B $i_2$W $O_{6}$ ), and spinel phase (Z $n_{2.33}$S $b_{0.67}$ $O_4$) were confirmed to be co-existed at the nodal point The average grain size increased in the range 15.5~29.9$\mu\textrm{m}$ with increasing W $O_3$ additive content. Consequently. W $O_3$ acted as a promotion additive of grain growth. As the W $O_3$ additive content increases. the varistor voltage and the nonlinear exponent decreased in the range 186.82~35.87V/mm and 20.90~3.34, respectively, and the leakage current increased in the range of 22.39~83.01 uh. With increasing W $O_3$ additive content, the barrier height and the density of interface states decreased in the range 1.93~0.43eV and (4.38~1.22)$\times$10$^{12}$ $\textrm{cm}^2$, respectively. W $O_3$ acted as an acceptor additive due to the donor concentration increasing in the range (1.06~0.38)$\times$10$^{18}$ /㎤with increasing W $O_3$ additive content.t.t.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.235-239
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• 2001

Effect of microwave treatment to barley bran was tested on antioxidative ability. Treatments of microwave at 100 W and 200 W, changed color of barley bran to brown, but carbonation was happening at 440 W. The electron donating abilities of barley bran was not reduced when treated with 100 W and 200 W microwave treatment for 10 minute. According to TBARS, the barley bran extract treated with 100 W and 200 W intensity of microwave for 10 min maintained the inhibition of lipid peroxidation, while the extract from 440 W microwave treatment for 5 min did not. Total phenolic contents were reduced with increased intensity of microwave treatment. The antioxidant activity of barley bran was not affected by microwave treatment at 100 W and 200 W, while the 440w microwave treatment reduced the activity due to carbonation of barley bran and decreased phenolic compounds.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.3
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• pp.198-204
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• 2022

In this paper, the 5kW and 50kW vertical axis wind turbines were studied using the ANSYS flow analysis simulation program. The 5 kW vertical shaft wind turbine has 30 units of the number of main blades and sub-blades and the electrical characteristics were analyzed by changing the tip speed ratio (TSR) from 0.2 to 06. A 50kW vertical axis wind turbine was designed based on the electrical characteristics of a 5kW vertical axis wind turbine. When the tip speed ratio was 0.5, the 5 kW wind power generation showed the maximum output of 9.5 kW and the efficiency of 0.28. The calculation of the power current(Ip) and the power voltage(Ep) show that, as the tip speed ratio increases, the power current(Ip) decreases and the power voltage(Ep) increases. And even if the tip speed ratio was changed, 5kW wind power generation was measured for output of 5 kW or higher. When the tip speed ratio was changed from 0.3 to 0.6, 50 kW wind power generation was output more than 50 kW. When the tip speed ratio of 50kW wind power generation was 0.4, the output was 58.37 [kW] and the efficiency was 0.318, and it was confirmed that the proposed 50kW wind power generation satisfies the design conditions.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.3
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• pp.492-501
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• 2015

To improve the shortcomings of baked Yugwa 0.5, 1.0, 1.5 and 2.0% natural ind igestible materials,- (gellan gum, glucomannan and carrageenan) were each treated with glutinous rice-baked Yugwa was processed, and quality imprpvements were deducted. Baked Yugwa with natural additives,- (gellan gum, glucomannan and carrageenan) was compared,- to additional test results with sample 1.5%(w/w) additives,- The one showing the highest preference from the sensory test was the acid number reference group at $2.19{\pm}0.42$, while the sample groups,- with different additives, were lower than the reference group by $1.48{\pm}0.39$ to $1.67{\pm}0.68$. The peroxide number reference group showed the highest preference of $49.34{\pm}0.42$, whereas the sample groups, with different additives, showed lower preferences than the reference group by $36.72{\pm}$0.42 compared to the sample group of glucomannan 1.5% (w/w), $32.45{\pm}0.59$ compared to the sample group of gellan gum 1.5%(w/w), and $28.65{\pm}0.56$ compared to the sample group of carrageenan 1.5% (w/w). According to the preference test targeting employees of Korean cake, manufacturers, there was no significant difference in color and flavor among all groups, whereas the sample group of carrageenan 1.5% (w/w) showed the highest scores in items of taste, texture and overall-preference, and also sample groups of glucomannan 1.5% (w/w) and gellan gum 1.5% (w/w) scored higher than the reference group. Baked Yugwa with 1.5% (w/w) additives of carrageenan, glucomannan and gellan gum have higher marketability by decreasing deterioration caused by oxidation of existing deep fried Yugwa and by improving the solid texture of baked Yugwa.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.4
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• pp.397-403
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• 1999

The author examined the response of Amberjacks, Seriola quinqueradiata [TEMMINCI et SCHLIBEL] to the surface attracting lamps (0.5W, 0.8W, 1W) line in the experimental water tank (550 L$\times$58W$\times$73Hcm).The attracting rate was investigated in accordance with the intervals of lighting and putting out hour (1,5 minute) when each of the attracting lamps was gradually switched off after they were switched on all at once. The results are as follows:1. Total distribution rate of fish in the illuminated section was 92.4% (mean 18.5%) in case of 1 minute interval, and 95.8% (mean 19.2%) in case of 5 minutes interva. 2. Mean distribution rate of fish at the illuminated section: Distribution rate at interval of 1 minute were 19.0% in 1W, 18.4% in 0.5W, and 18.0% in 0.8W respectively. distribution rate at interval of 5 minutes were 19.5% in 1W, 19.2% in 0.5 W, and 18.8% in 0.8W respectively.3. Attracting rates of the last section showed very much increasing as illuminating time elapsed, but there was a little difference of attracting rates according to interval and lighting source. 4. Attracting rate of fish in only last section switched on : Attracting rate at interval in case of 1 minute were 97.0% in 1W, 86.0% in 0.8W and 74.0% in 0.5W respectively. Attracting rate at interval in case of 5 minutes were 97.3% in 1W, 90.0% in 0.5W and 88.0% in 0.8W respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.1
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• pp.42-49
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• 1996

The author examined the response of Armorclad rockfish, Sebastes hubbsi [MATSUBARA]to the surface attracting lamps (0.5W, 0.8W, 1W) line in the experimental water tank ($550L{\times}58W{\times}73H$cm). The attraction rate was investigated in accordance with the intervals of lighting and putting out hour (1,5 minute) when each of the attraction lamps was gradually switched off after they were switched on all at once. The results are as follows : 1. Total distribution rate of fish in the illuminated section was 61.6%(mean 12.3%) in case of 1 minute interval, and 41.0%(mean 8.2%) in case of 5 minutes interval. 2. Mean distribution rate of fish at the illuminated section : \circled1Distribution rate at interval of 1 minute were 12.7% in 0.8W, 12.4% in 0.5W and 11.9% in 1 W respectively. \circled2Distribution rate at interval of 5 minutes were 9.0% in 1W, 8.6% in 0.8W and 7.0% in 0.5W respectively. 3. Attraction rates of the last section showed a little increasing as illuminating time elapsed. A difference of attraction rates according to lighting source in 1 minute interval was bigger than that in 5 minute interval. 4. Attraction rate of fish in only last section switched on : \circled1Attraction rate at interval in case of 1 minute were 52.0% in 0.8W, 46.7% in 0.5%W and 45.3% in 1W respectively. \circled2Attraction rate at interval in case of 5 minutes were 32.0% in 1W, 24.0% in 0.8W and 14.7% in 0.5W respectively.