• Wind and Structures
• /
• v.12 no.3
• /
• pp.205-217
• /
• 2009

Aerodynamic flutter control for long-span cable-supported bridges was investigated based on three basic girder sections, i.e. streamlined box girder section, box girder section with cantilevered slabs and two-isolated-girder section. Totally four kinds of aerodynamic flutter control measures (adding fairings, central-slotting, adding central stabilizers and adjusting the position of inspection rail) were included in this research. Their flutter control effects on different basic girder sections were evaluated by sectional model or aeroelastic model wind tunnel tests. It is found that all basic girder sections can get aerodynamically more stabled with appropriate aerodynamic flutter control measures, while the control effects are influenced by the details of control measures and girder section configurations. The control effects of the combinations of these four kinds of aerodynamic flutter control measures, such as central-slotting plus central-stabilizer, were also investigated through sectional model wind tunnel tests, summarized and compared to the flutter control effect of single measure respectively.

• Journal of electromagnetic engineering and science
• /
• v.17 no.4
• /
• pp.197-201
• /
• 2017

In this paper, we present a novel design for a dual-band bandpass filter (BPF) based on the conventional second-order, open-loop BPF. By adding series resonant circuits to the open ends of the resonator, we can create two resonant modes from the even and odd modes. One pair of the even and odd modes constitutes the upper passband, while the other pair constitutes the lower passband. By adding another series resonant circuit to the open-loop resonator, we can control the bandwidth of either the upper passband or the lower passband. We can replace the series resonant circuits with simple microstrip line resonators. A dual-band BPF working at both Wi-Fi bands (2.4 GHz and 5.8 GHz bands) is designed based on the proposed method and is tested. The measured and simulated results show excellent agreement.

• Journal of the Korea Institute of Building Construction
• /
• v.5 no.2 s.16
• /
• pp.131-138
• /
• 2005

Most concrete is recently made of an aggregate which is properly absorbed, and carried in it in order to do capability at every fields. We have been close to demand new rapability of high flowing and enduring for specific concretes. That is difficult to cope with claiming the efficiency on deterioration from lack of a high quality aggregate. Therefore, For solving the problems we apply to a packing method for using dried materials. That is to say that it is a kind of making into an instant. In this study. There is a purpose to present fundamental data, comparing and analyzing a phenomenon of aggregate's absorption following the rate of adding water, for using existing materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.493-496
• /
• 2003

Electrical characteristic of tracking resistance, volume resistance, insulation breaking strength etc. and mechanical characteristic are required to high voltage insulation insulator silicone rubber. Tracking resistance is adding much ATH to improve tracking resistance as the most important factor among them. But, there is problem that mechanical strength grows worse rapidly adding much ATH. Therefore, this research studied effect that flame retardant gets to tracking resistance during factor that influence to tracking resistance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1994.11a
• /
• pp.21-23
• /
• 1994

By adding La₂O₃ to optical multicomponent glass composition, after making mother glass and core fiber that enable to enlarge the infrared transmittance region, then surveyed the optical properties. Through thermal analysis of the glass abstained by melt-quenching after selecting stable basic composition on devitrification and replace SiO₂ by 4-12wt% La₂O₃. As La₂O₃ increases up to l2wt% transition temperature, refractive index, density, deformation temperature increased, whereas thermal expansion coefficient decreased. As a result of inspectig transmittance in UV/VIS/IR region, visable region indicated the decrease of transmittance by increasing the La₂O₃ and transmittance region was enlarged by increasing the La₂O₃ in IR region. Also, fabricate core fiber at 820℃ and severy the optical loss we could fact that La₂O₃ composition added 12wt% showed the minimum optical loss.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.11 s.242
• /
• pp.1248-1256
• /
• 2005

This study was undertaken to investigate the flow characteristics of emulsified fuel with the ultrasonic energy-adding system by using the chaotic method. Efffcts of water contents within emulsified fuel, flow rate and tube length with 5m in diameter from an emulsified chamber has been discussed on the strange attractor and power spectral density function. Five probe sensors were set up from 0.5 to 2.5m by length in 0.5m increments in the tube. In particular, the chaotic features of this system have been practically characterized in terms of chaotic statistics such as the power spectral density function and phase space portraits by resorting to the somewhat noble deterministic chaos theory. In the tube, the dominant frequency increased with increasing water contents and flow rate, but decreased a little with an increase in the length from the emulsified chamber.

• Journal of the Korean Society of Food Culture
• /
• v.18 no.4
• /
• pp.356-364
• /
• 2003

The purpose of this study was to evaluate quality characteristics of the bread added with chlorella growth factor(CGF). The bread was manufactured by adding 0.5%, 1.0%, 1.5% or 2.0% of CGF(w/w) to wheat flour. The bread volume was increased from 1,755mL to 1,840mL as CGF contents increased from 0% to 1.0%. The lightness(L values)and the redness(a values) decreased with increasing CGF contents, but the yellowness(b values) increased with increasing CGF contents. Textural characteristics of the bread were influenced by adding the CGF. The breads containing CGF showed a decrease in hardness, springiness, gumminess and chewiness. In sensory evaluation, sensory scores decreased with increasing CGF contents for color. On the other hand, the highest sensory scores for grain, flavor, taste, softness, chewiness, aftertaste and overall acceptability were obtained, when CGF content was 1.0%. In conclusion, the bread with 1.0% CGF was the best quality in textural and sensory evaluation.

• Korean journal of food and cookery science
• /
• v.15 no.2
• /
• pp.163-170
• /
• 1999

To investigate the effect of adding sugars and lipids on characteristics of cooked rice, the solubility, swelling power, blue value, amylogram and sensory evaluation characteristics of cooked rices with 0.5, 1.0, 1.5, 2.0% level of sugars and lipids additives were measured. The solubility, swelling power and blue value of cooked rice with sugars were increased as the more sugars were added. Those parameters of the cooked rice with isomalto oligosaccharide were higher than sucrose. The solubility decreased as the more lipids were added. The swelling power decreased as the more lipids were added. As the result of amylograph analysis, addition of isomalto oligosaccharide accelerates the gelatinization and retards the retrogradation. In sensory evaluation, the cooked rice with 0.5% level of sucrose and isomalto oligosaccharide were showed better acceptability than the others. In conclusion, the additions of sugars and lipids affect characteristics of cooked rice. Especially, the cooked rice with 0.5% isomalto oligosaccharide was showed the best physiochemical and sensory properties.

• Journal of the Korean Society of Food Culture
• /
• v.20 no.6
• /
• pp.675-682
• /
• 2005

This study was aimed to determine microbiological quality by adding green tea extracts to chicken meat salad. For this study, Chicken meat salad were prepared with two production method. (method 1: addition of green tea extracts to boiling phase, method 2: addition of green tea extracts to salad dressing) Microbiological effects of green tea extracts were assessed during production process by measuring process time, temperature, pH and Aw and determining total plate counts and coliforms. Effects of green tea extracts on total plate counts and coliforms were observed during holding at 3, 10, $25{\pm}1^{\circ}C$ for 12 hours. Green tea extracts improved the microbiological quality and showed antibacterial properties when they are added to chicken meat salad.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2006.05a
• /
• pp.27-30
• /
• 2006

This study investigated influence of organic fiber type and contents on engineering properties of concrete. Test showed that increase of fiber contents decreased fluidity of fresh concrete and it was even worse in concrete adding cellulose fiber. It is decided that concrete containing more than proper level of fiber should be considered. In addition, concrete adding more fiber, nylon and cellulose, resulted in increase of air content but it was satisfied in aimed value. Bleeding capacity of concrete containing more fiber significantly declined and setting time of that was also slightly retarded. For the properties of strength, both compressive and tensile strength of fiber containing concrete were indicated at similar value to control concrete. However, it is clear that if those concrete containing fiber revised the value of increased air contents at fresh state, the strength value of that would be slightly increased.