• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.253-258
• /
• 2012

In this study, designs of the high efficiency composite propeller blade for a high speed turboprop aircraft, which will be used for a next generation regional commercial aircraft in Korea, are performed. Both the vortex theory and the blade element theory are used for preliminary aerodynamic design and performance analysis of the propeller. Then the aerodynamic design result is confirmed through performance analysis using a commercial CFD code, ANSYS. The carbon/epoxy composite materials is used, and the skin-spar-foam sandwich type structure is adopted for improvement of lightness and structural stability. Finally, it is investigated that the proposed propeller blade has high efficiency and structural safety through both aerodynamic and structural analysis and experimental test of a prototype propeller blade.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.30 no.2
• /
• pp.78-81
• /
• 2020

Quantum dot efficiency was increased to evaluate reliability and optical characteristics using incidental materials. Quantum dot was manufactured by wrapping a sandwich type quantum layer using a product with a barrier property to prevent water and oxygen because it is vulnerable to oxygen and moisture. We used the three quantum dot films consisting of quantum dot only and quantum dot products consisting of film and barrier film combined with PET in the quantum dot product to evaluate the change over 650 hours under high temperature and high humidity conditions at 60℃ and 90 % humidity. As a result, the quantum dot product with Barrier Film has lowered luminance by 8 %, CIE x by 2 % and CIE y by 8 %. Quantum dot products exposed to moisture and oxygen were oxidized and measured low before measurement.

• The Journal of Korean Oriental Chronic Disease
• /
• v.10 no.1
• /
• pp.1-20
• /
• 2005

Background and Objective: The importance of the presence of eosinophils in the airways of patients with fetal asthma has long been recognized, but the mechanism by which these cells are recruited and retained in the lung are only now being elucidated. Eotaxin is a potent and specific eosinophil chemoattractant that is mobilized in the respiratory epithelium after allergic stimulation. Material and Methods: We used water extracts of Liripois Tuber and pulmonary epithelial cell lines A549(human typeII-like epithelial cells) and human eosinophils. We estimated cytotoxic effects of Liripois Tuber via MTS assay, and estimated the effects of Liripois Tuber on chemokines from prestimulated A549 cells by sandwich ELISA and RT-PCR. We conducted chemotaxis assay on prestimulated eosinophils treated with Liripois Tuber. Result: In this study we demonstrated that $TNF-{\alpha}$, IL-4 and $IL-1{\beta}$ induced the accumulation of chemokines mRNA in the pulmonary epithelial cell lines A549 in dose-dependent manner. Chemokines were inhibited by Liripois Tuber in dose-dependent manner. The eosinophil migration was inhibited at high concentration of Liripois Tuber. Conculusion: These findings indicate that the supression of the expression of chemokines can be accomplished by Liripois Tuber treatment, raising the possibility that Liripois Tuber might be of therapeutic value in diseases such as asthma.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.3
• /
• pp.323-328
• /
• 2004

Down-conversion of Eu$^{3+}$ doped LiGdF$_4$ (LGF) for increasing the cell efficiency on dye-sensitized Ti $O_2$ solar cells has been studied. The dye sensitized solar cell (DSC) consisting of mesoporous Ti $O_2$ electrode deposited on transparent substrate, an electrolyte containing I$^{[-10]}$ /I$_3$$^{[-10]}$ redox couple, and Pt counter electrode is a promising alternative to the inorganic solar cell. The structure of DSC is basically a sandwich type, viz., FTO glass/Ru-red dye-absorbed Ti $O_2$/iodine electrolyte/sputtered Pt/FTO glass. The cell without down converter had open circuit potential of approximately 0.66 Volt, the short circuit photocurrent density of 1.632 mA/$\textrm{cm}^2$, and fill factor of about 50 ％ at the excitation wavelength of 550 nm. In addition, 5.6 mW/$\textrm{cm}^2$ incident light intensity beam was used as a light source. From this result, the calculated monochromatic efficiency at the wavelength of 550 nm of this cell was about 9.62 ％. The incident photon to current conversion efficiency (IPCE) of N3 used as a dye in this work is about 80 ％ at around 590 nm and 610 nm, which is the emission spectrum of Eu$^{3+}$ doped LGF, results in efficiency increasing of DSC.C.

• The Journal of Internal Korean Medicine
• /
• v.26 no.1
• /
• pp.129-142
• /
• 2005

Objective : Asthma is known as chronic airway inflammatory disease. This inflammation is conducted by various inflammatory cells including eosihophil. Chemotaxis is one way that circulating inflammatory cells invade a specific lesion. This study examines the degree to which Lonicerae Flos inhibits eosinophil chemotaxis at pulmonary epithelium after allergic stimulation. Material and Methods : Water extracts of Lonicerae Flos and pulmonary epithelial cell lines A549(human type II-like epithelial cells) and human eosinophils were used. Cytotoxic effects of Lonicerae Flos via MTS assay were estimated, as well as the effects of Lonicerae Flos on chemokines from prestimulated A549 cells by sandwich ELISA and RT-PCR. Chemotaxis assay was conducted on prestimulated eosinophils treated with Lonicerae Flos. Result : In this study $TNF-{\alpha}$ and IL-4, $IL-l{\beta}$ were seen to induced the accumulation of chemokines mRNA in the pulmonary epithelial cell lines A549 in a dose-dependent manner. Chemokines were inhibited by Liripois Tuber in a dose-dependent manner and especially, IL-8 and ICAM-l were inhibited considerably at $100\;{\mu}g/ml$ concentration of Lonicerae Flos. The eosinophil migration is inhibited in high concentration of Lonicerae Flos in a dose-dependent manner. Conclusion : These findings indicate that the supression of the expression of chemokines can be accomplished by Lonicerae Flos treatment, raising the possibility that Lonicerae Flos might be of therapeutic value in diseases such as asthma.

• The Journal of Internal Korean Medicine
• /
• v.26 no.1
• /
• pp.199-212
• /
• 2005

Objective : Airway inflammation is now regarded as a defining feature of asthma. The importance of eosinophits in the airway inflammation of asthma patients is widely recognized, and eosinophils mobilization in the respiratory epithelium is activated by chemoattractants and cytokines. This study was designed to examine the extent of the ability of Moutan Cortex Radicis to inhibit eosinophil chemotaxis of pulmonary epithelium after allergic stimulation. Material and Methods : Water extracts of Moutan Cortex Radicis and pulmonary epithelial cell lines A549(human type II-like epithelial cells) and human eosinophils were used. Cytotoxic effects of Moutan Cortex Radicis were estimated via MTS assay, and the effects of Moutan Cortex Radicis on chemokines from prestimulated A549 cells were estimated by sandwich ELISA and RT-PCR. Chemotaxis assay on prestimulated eosinophils treated with Moutan Cortex Radicis. was conducted Result : In this study we demonstrated that $TNF-{\alpha}$ and IL-4, $IL-1{\beta}$ induced the accumulation of chemokines' mRNA in the pulmonary epithelial cell lines A549 in a dose-dependent manner. Chemokines of eotaxin, ICAM-1, YCAM-1, IL-8, IL-16 were inhibited by Moutan Cortex Radicis in a dose dependent manner, but RANTES showed no inhibition due to Moutan Cortex Radicis. Eosinophil migration was inhibited at high concentrations of Moutan Cortex Radicis. Conculusion : These findings are indicative of supression of chemokines accomplished by Moutan Cortex Radicis treatment, demonstrating the potential therapeutic value of Moutan Cortex Radicis for treating diseases such as asthma.

• Journal of the Korean Wood Science and Technology
• /
• v.15 no.3
• /
• pp.44-55
• /
• 1987

In order to study the effect of sawdustboard combined with plastic chips, 0.5mm($T_1$), 1mm($T_2$), 1.4mm($T_3$) thick nylon fiber. polypropylene rope fiber(RP), and 0.23mm thick moth-proof polypropylene net fiber(NP) were cut into 0.5, 1, 2cm long plastic chips. Thereafter, sawdustboard combined with plastic chips prepared as the above and plastic non-combined sawdustboard(control) were manufactured into 3 types of one-, two-, and three layer with 5 or 10% combination level. By the discussions and results at this study, the significant conclusions of mechanical and physical properties were summarized as follows: 1. The MORs were shown in the order of 3 layer> 2 layer> 1 layer among plastic non-combined boards, and $T_3$ < $T_2$ < $T_1$ < RP (NP(5%) < NP(l0%) among plastic combined boards. In 2cm long plastic chip in 1 layer board, the highest strength through all the composition was recognized. 1 layer board showing the lower strength with 0.5cm plastic chip rendered to the bending strength improvement by 2 or 3 layer board composition. On the other hand, 2 or 3 layer combined with 1, 2cm long polypropylene net fiber chips incurred MOR's conspicuous decrease requiring optimum plastic chip combined level and consideration to combined type. 2. MOE in plastic non-combined 3 layer board exhibited sandwich construction effect by higher resin content application to surface layer in the order of 3layer>1layer>2layer with the highest stiffness of the board combined with polypropylene chip, while nylon chip-combined board had little difference from plastic non-combined board. In relevant to length and layer effect, 3 layer board combined with the 0.5cm long polypropylene net fiber chip in 5% and 10% combined level presented 34-43% and 44-76% stiffness increase against plastic non-combined board(control), respectively. Moreover, in 1 layer board, 30% stiffness increase with 10% against 5% combined level in the 1 and 2cm long polypropylene net fiber chip was obtained. 3. Stress at proportional limit(Spl) showing the fiber relationship (r: 0.81-0.97) between MOR presented in the order of 1 layer<2 layer<3 layer in plastic non-combined board. Correspondingly, combined effect by layer and plastic chip length was similar to MOR's. 4. Differently from previous properties(MOR, MOE, Spl). work to maximum load(Wml) of 2 layer board approached to that of 3 layer board. Conforming the above phenomenon. 2 layer combined with 0.5cm long polypropylene net fiber chip kept the greater work than 1 layer. The polypropylene combined board superior to nylon -and plastic non - combined board seemed to have greater anti - failing capacity. 5. Internal bond strength(IB), in contrast to MOR's tendency. showed in the order of T1

• Journal of the Society of Disaster Information
• /
• v.15 no.4
• /
• pp.469-478
• /
• 2019

Purpose: In this studies we examine the facilities damage characteristics caused by forest fire. Therefore, we surveyed damaged facilities from forest fire which was occurred on Goseong-Gun on march 28 in 2019.(damaged areas was 40ha) The types of facilities uses were house, public facility, warehouse and so on. 17 facilities were destroyed. The purpose of this study was to for establishing a disaster safety village in rural areas where damage from a similar type of disaster occurs repeatedly by conducting the consciousness survey targeting at experts and disaster safety officials in a local government. Method: We surveyed meteorological factors(temperature, wind speed, wind direction, humidity) per a minute for analyzing weather condition on Goseong-Gun when forest fire was occurred, spread and extinguished. And we surveyed forest fire risk factors(a slope degree, a slope direction, a geographical feature, a distance between forest and facility, main species, the existence of crown fire ignition, the direction of facility, the main material of building) around 10 damaged facilities. Finally, we analyzed damage pattern of facilities using meteorological factor and forest fire reisk fator Result: The weather condition of Kanseonng AWS (No.517) was high temperature, arid and strong wind, when the forest fire was occurred and spread. An average wind speed was 4.1m/s and the maximum wind speed was 11.6m/s. The main direction of wind was W(225~315°). Damaged facilities were located on the steep slope area and on the mountaintop. The forest density around facilities was high and main species was korean red pine. The crown fire was occurred in the forest around damaged facilities. The average distance was 13.5m from forest to facilities. When the main matarial of building was made by fire resistance materials (for example, rainforced concrete), the damage was slightly. on the other hand, when by flammable material (for example, a Sandwich Panel), the facilities were totally destroyed Conclusion: The results of this research which were the thinning around house, making a safety distance, the improvement of main material of building and etc, will be helpful for establishing a counter measure for a forest fire prevention of facilities in wild land urban interface