• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.621-625
• /
• 2007

Oscillating wave amplitude in a bottom-mounted owe chamber designed for wave energy converter is investigated by applying characteristic wave conditions in Korean coastal water. The effects of shape parameters of OWC chamber in a view of wave energy absorbing capability are analyzed. Both experimental and numerical approaches are adopted and their results are compared to optimize the shape parameters which can result in a maximum power production under given wave distribution. The experiment was carried out in a wave flume under 2-D assumption of OWC chamber. In numerical scheme, the potential problem inside the chamber is solved by use of the Green integral equation associated with the Rankine Green function, while outer problem with the Kelvin Green function taking account of fluctuating air pressure in the chamber. Air duct diameter, chamber width, and submerged depths of front skirt and back wall of chamber changes the magnitude and peak frequency of wave absorption significantly.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
• /
• pp.1218-1220
• /
• 2005

We have developed laser absorption spectroscopy system for the measurement of excited Xe atoms in micro-discharged AC-PDP plasma. In this study, we have measured the absorption signals for the $1S_5$ xenon metastable state in the PDP cell with the various gas mixtures of Ne-Xe(1%), Ne-Xe(4%) and Ne-Xe(10%) under fixed gas pressure of 350 Torr and the eletrode gap distance of 50um. It is found that the maximum excited xenon densities are $1.2^{\ast}10^{12}\;cm^{-3}$, $1.8^{\ast}10^{12}\;cm^{-3}$ and $2.7^{\ast}10^{12}cm^{-3}$ for gas mixtures of Ne-Xe(1%), Ne-Xe(4%) and Ne-Xe(10%) respectively, in this experiment.

• 대한가정학회지
• /
• 제42권7호
• /
• pp.63-72
• /
• 2004

This study discussed the dyeing of wool and cotton fabrics with Betel Palm Tree White woolen fabrics and cotton fabrics purchased from HATH (Korea Apparel Testing ＆ Research Institute) were used as experimental fabrics. Using dyeing powder extracted from dyeing material, various temperatures, dyeing times, and pH were used in the dyeing process. Al, Cr, Fe, Cu, and Sn were used as mordant and the absorption was compared with different mordanting methods. The optimum condition for pre-mordanting dyeing was dye concentration of 25% (o.w.f) and mordant concentration of 0.5$^{\circ}$∼1%. Woolen fabric showed an increase of absorption and the maximum absorption was achieved at weak acidity. According to the mordanting methods, woolen fabrics and cotton fabrics were treated with various mordanting agents, a mordant rate of 1:100, at 60$^{\circ}C$, for 30 minutes and dyed with a dyeing material concentration of 25% (o.w.f), at a rate of 1:100, at 60$^{\circ}C$ for 60 minutes. The best dyeing effect w3s achieved at the temperature of 60$^{\circ}C$ for cotton and 80$^{\circ}C$ for wool fabrics. The light fastness of cotton and wool fabrics was low and particularly the fastness to perspiration was decreased with Fe mordanting. I concluded that pre-mordanting method was better than post-mordanting method for cotton and woolen fabrics.

• 한국가구학회지
• /
• 제27권2호
• /
• pp.137-144
• /
• 2016

Wood plastic composite (WPC) is a green composite made of wood flour and thermoplastics to provide better performance by removing the defects of both wood and plastics. However, relatively low thermal stability and poor fire resistance of wood and plastics included in WPC have been still issues in using WPC as a building material for interior applications. This study investigated the effect of environmentally-friendly flame retardants (EFFRs) on the mechanical, thermal, morphological, and water absorption properties of wood flour (WF)/talc/polypropylene (PP) composites in comparison with neat PP. The whole EFFRs-filled WF/talc/PP composites showed higher values in flexural strength, flexural modulus, and impact strength compared to neat PP. In thermal properties, aluminum hydroxide (AH)-filled composite showed a $36^{\circ}C$ reduction in maximum thermal decomposition temperature ($T_{max}$) compared to neat PP, but magnesium hydroxide (MH) played an important role in improving thermal stability of filled composite by showing the highest $T_{max}$. From this research, it can be said that MH has potentials in reinforcing PP-based WPCs with improvement of thermal stability.

• Bulletin of the Korean Chemical Society
• /
• 제31권11호
• /
• pp.3272-3278
• /
• 2010

Synthesis and structural characterization of peripherally ferrocene-substituted zinc phthalocyanine (ZnPc-Fc) were carried out for efficient far-red/near-IR performance in dye-sensitized nanostructured $TiO_2$ solar cells. Incorporating ferrocene into phthalocyanine strongly improved the dye solubility in polar organic solvents, and reduced surface aggregation due to the steric effect of bulky ferrocene substituents. The involvement of electron transfer reaction pathways between ferrocene and phthalocyanine in ZnPc-Fc was evidenced by completely quenched fluorescence from S1 state (< 0.08% vs ZnPc). Strong absorption bands at 542 and 682 nm were observed in the transient absorption spectroscopy of ZnPc-Fc in DMSO, which was excited at a 670 nm laser pulse with a 15 ps full width at half maximum. Also, the excited state absorption signals at 450 - 600 and 750 - 850 nm appeared from the formation of charge separated state of phthalocyanine's anion. The lifetime of the charge separate state in ZnPc-Fc was determined to be $170{\pm}8$ ps, which was almost 17 times shorter than that of the ZnPc.

• Journal of Pharmaceutical Investigation
• /
• 제30권4호
• /
• pp.283-288
• /
• 2000

The purpose of the present study was to investigate the topical bioavailability of retinol (vitamin A) after its transdermal administration. For this purpose, we developed the convenient HPLC method to measure the retinol concentration in the biological fluids such as plasma and skin tissues. The low detection limit was $0.1\;{\mu}g/ml$ using a gradient HPLC system of UV detection. The initial plasma concentration of retinol was about $20\;{\mu}g/ml$ after its i.v. bolus administration (4.32 mg/kg). The half life $(t_{1/2{\alpha}})$ in the distributive phase was 1.3 min, while retinol was slowly disappeared in the post-distributive phase. On the other hand, the maximum plasma concentration $(C_{max})$ was about 776 ng/ml after appling to rat skin at a dose of 43.2 mg/kg. Furthermore, the concentration of retinol in the skin tissues was about 600 ng/g tissue at 12 hr after its transdermal administration. In conclusion, the initial plasma concentration of retinol was comparable with the skin concentration after its cutaneous absorption, followed by being decreased with the passage of the time.

• Journal of Pharmaceutical Investigation
• /
• 제21권4호
• /
• pp.247-251
• /
• 1991

Effects of aluminum magnesium hydroxide (A) and cimetidine (C) on the pharmacokinetics of minocycline (M) were investigated in female rats. Blood samples were collected at various time intervals until 36 hrs following oral dosing of drugs. Plasma minocycline concentrations were determined by HPLC. Control group (M), $T_1$ group (M+A), $T_2$ group (A+M after 2 hrs), $T_3$ group (M+A after 2 hrs), $T_4$ group (M+C) and $T_5$ group (C+M after 2 hrs) were divided to examine interaction of the drugs with minocycline. Plasma minocyline level-time curves were well described by two-compartment open model with first-order absorption in rats. Antacid treatment was associated with reduced of 71.0, 45.9, 35.7% in minocycline absorption rate $constant(K_{\alpha})$, maximum plasma $concentration(C_{max})$, and relative $bioavailability(F_{rel})$, respectively. Cimetidine treatment group exhibited no significant changes in plasma level-time curve when compared with control group and did not affect minocycline absorption as by any of these three parameters.

• Geomechanics and Engineering
• /
• 제17권4호
• /
• pp.393-403
• /
• 2019

The cycling impact test of red sandstone soil under different axial pressure and different impact loads are conducted to reveal the mechanical properties and energy consumption mechanism of red sandstone soil with static-dynamic coupling loading. The results show that: Under the action of different axial pressure and different impact loads, the peak stress of the specimen increases, and then tends to be stable with the times of impact. With the increase of impact times, the specific energy absorption value of the red sandstone soil specimen is increased first and then gentle development trend. When the impact loads are certain, the larger the axial pressure is, the smaller the peak value of energy absorption, which indicates that the energy utilization rate is not high under the condition of large axial pressure. Through the analysis of energy utilization, it is found that the smaller the impact load, the higher the energy utilization rate. The greater the axial pressure, the lower the energy utilization rate. when the axial pressure is large, the impact loads corresponding to the maximum values of reflectivity, transmissivity and absorptivity are the same. The relationship between reflectivity and transmissivity is negatively correlated.

• 한국전자파학회논문지
• /
• 제29권12호
• /
• pp.963-968
• /
• 2018

본 논문에서는 수동소자를 이용한 소형 공통 모드 필터를 설계 및 제작하였다. 주어진 주파수 응답을 갖는 공통 모드 필터를 설계하기 위해 차동 모드와 공통 모드에서 등가회로를 분석하였다. 제안된 구조는 기존의 ${\lambda}/4$ 공진기로 구현된 필터에 비해 60 %의 크기가 감소하였다. 또한, 제작된 공통 모드 필터는 ${\mid}S_{dd11}{\mid}$, ${\mid}S_{cc21}{\mid}$, ${\mid}S_{cc11}{\mid}$ < -10 dB를 만족하는 27.5 %의 공통 모드 흡수 대역폭에서 최대 1.2 dB의 차동 모드 삽입손실과 최소 78.2 %의 공통 모드 흡수 효율을 갖는다.

• Advances in concrete construction
• /
• 제11권1호
• /
• pp.73-80
• /
• 2021

Rice Husk Ash (RHA) geopolymer paste activated by sodium aluminate were characterized by X-ray diffractogram (XRD), scanning electron microscope (SEM), energy dispersion X-Ray analysis (EDAX)and fourier transform infrared spectroscopy (FTIR). Five series of RHA geopolymer specimens were prepared by varying the Si/Al ratio as 1.5, 2.0, 2.5, 3.0 and 3.5. The paper focuses on the correlation of microstructure with hardened state parameters like bulk density, apparent porosity, sorptivity, water absorption and compressive strength. XRD analysis peaks indicates quartz, cristobalite and gibbsite for raw RHA and new peaks corresponding to Zeolite A in geopolymer specimens. In general, SEM micrographs show interconnected pores and loosely packed geopolymer matrix except for specimens made with Si/Al of 2.0 which exhibited comparatively better matrix. Incorporation of Al from sodium aluminate were confirmed with the stretching and bending vibration of Si-O-Si and O-Si-O observations from the FTIR analysis of geopolymer specimen. The dense microstructure of SA2.0 correlate into better performance in terms of 28 days maximum compressive strength of 16.96 MPa and minimum for porosity, absorption and sorptivity among the specimens. However, due to the higher water demand to make the paste workable, the value of porosity, absorption and sorptivity were reportedly higher as compared with other geopolymer systems. Correlation regression equations were proposed to validate the interrelation between physical parameters and mechanical strength. RHA geopolymer shows comparatively lower compressive strength as compared to Fly ash geopolymer.