• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1137-1143
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• 2009

Experiments were conducted to evaluate pool boiling heat transfer performance between plain and micro finned surfaces with FC-72, which is chemically and electrically stable. Three kinds of micro fins with the dimension of $100{\mu}m\;{\times}\;10{\mu}m$, $150{\mu}m\;{\times}\;10{\mu}m$ and $200{\mu}m\;{\times}\;10{\mu}m$ (width $\times$ height) were fabricated on the surface of a silicon chip. The experiments were carried out on the liquid subcooling of 5, 10 and 15 K under the atmospheric condition. The micro finned surface with a larger fin width of $200{\mu}m$ provided a better pool boiling heat transfer performance. Also, the micro finned surfaces showed a sharp increase in heat flux with increasing wall superheat and a larger heat transfer enhancement compared to a plain surface.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1837-1844
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• 2009

In this paper, the circuit of 2 variable ternary adder and multiplier circuit using current mode CMOS are implemented. The presented ternary adder circuit and multiplier circuit using current mode CMOS are driven the voltage levels. We show the characteristics of operation for these circuits simulated by HSpice. These circuits are simulated under $0.18{\mu}m$ CMOS standard technology, $5{\mu}A$ unit current in $0.54{\mu}m/0.18{\mu}m$ ratio of NMOS length and width, and $0.54{\mu}m/0.18{\mu}m$ ratio of PMOS length and width, and 2.5V VDD voltage, MOS model Level 47 using HSpice. The simulation results show the satisfying current characteristics. The simulation results of current mode ternary adder circuit and multiplier circuit show the propagation delay time $1.2{\mu}s$, operating speed 300KHz, and consumer power 1.08mW.

• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.533-542
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• 2007

The general characteristics of fine particle and meteorological analysis of high $PM_{10}$ concentration day which was over $100{\mu}g/m^3$ in busan were investigated for period of 2002 to 2006. Annual mean concentration including Asian dust day was $68.7{\mu}g/m^3$ in 2002, $54.6{\mu}g/m^3$ in 2003, $60.4{\mu}g/m^3$ in 2004, $58.3{\mu}g/m^3$ in 2005 and $58.8{\mu}g/m^3$ in 2006, respectively. Seasonal mean concentration was $73.4{\mu}g/m^3$ in Springtime, $56.8{\mu}g/m^3$ in Summertime, $55.5{\mu}g/m^3$ in Wintertime and $54.4{\mu}g/m^3$ in Falltime, respectively. Mean concentration for land use was 69.2 $37.0{\mu}g/m^3$ in industrial area, 64.2 $35.5{\mu}g/m^3$ in rural area, 62.6 $34.4{\mu}g/m^3$ in commercial area and 55.3 $33.8{\mu}g/m^3$ in residential area, respectively. Frequency of synoptic pattern for high $PM_{10}$ concentration day was 18 days(16.7%) in I type, 27 days(25.0%) in II type, 10 days(9.3%) in III type, 5 days(4.6%) in IV type, 13 days(12.0%) in V type and 29 days (26.9%) in VI type, respectively. Frequency of long range transport sector for high $PM_{10}$ concentration day was 9 days(8.3%) in I type, 64 days(59.5%) in II type, 34 days(31.5%) in III type, 1 days in IV type, 0 days, respectively.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.535-543
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• 2012

The aerosol number concentration have measured with an aerodynamic particle sizer spectrometer(APS) at Gosan site, which is known as background area in Korea, from January to September 2011. The temporal variation and the size distribution of aerosol number concentration have been investigated. The entire averaged aerosol number concentration in the size range 0.25~32.0 ${\mu}m$ is about 252 particles/$cm^3$. The number concentration in small size ranges(${\leq}0.5{\mu}m$) are very higher than those in large size ranges, such as, the number concentration in range of larger than 6.5 ${\mu}m$ are almost zero particles/$cm^3$. The contributions of the number concentration to PM10 and/or PM2.5 are about 34%, 20.1% and 20.4% in the size range 0.25~0.28 ${\mu}m$, 0.28~0.30 ${\mu}m$ and 0.30~0.35 ${\mu}m$, respectively, however, the contributions are below 1% in range of larger than 0.58 ${\mu}m$. The monthly variations in the number concentration in smaller size range(<1.0 ${\mu}m$) are evidently different from the variations in range of larger than 1.0 ${\mu}m$, but the variations are appeared similar patterns in smaller size range(<1.0 ${\mu}m$), also the variations in range of larger than 1.0 ${\mu}m$ are similar too. The diurnal variations in the number concentration for smaller particle(<1.0 ${\mu}m$) are not much, but the variations for larger particle are very evident. Size-fractioned aerosol number concentrations are dramatically decreased with increased particle size. The monthly differences in the size-fractioned number concentrations for smaller size range(<0.7 ${\mu}m$) are not observed, however, the remarkable monthly differences are observed for larger size than 0.7 ${\mu}m$.

• Korean Journal of Plant Tissue Culture
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• v.28 no.6
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• pp.311-315
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• 2001

The relationship among leaf size, leaf protoplast (cell) size, chloroplast size, and chloroplast number were investigated in tobacco and Arabidopsis thaliana at various developmental stages. In tobacco, protoplasts, less than 15.6 ${\mu}{\textrm}{m}$ in diameter had less than 20 chloroplasts, 0.93 ${\mu}{\textrm}{m}$ in thickness and 3.3 ${\mu}{\textrm}{m}$ in length on average. As protoplast size increased from 30 ${\mu}{\textrm}{m}$ to 45 ${\mu}{\textrm}{m}$ in diameter, chloroplast size remained the same (1.57 ${\mu}{\textrm}{m}$ in diameter and 5.55 ${\mu}{\textrm}{m}$ in length on average), but chloroplast number increase from 42 to 101 on average. A similar relationship was also observed in A. thaliana. The ratio of total chloroplast volume to protoplast volume was constant (0.105 in tobacco and 0.325 in A. thaliana) over various developmental stages.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.25-31
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• 1997

Antioxidative activity of daidzin and puerarin isolated from Puerariae radix against oxidation of low density lipoprotein(LDL) was investigated. The concentration of daidzin at 100$\mu\textrm{g}$/$m\ell$ and puerarin at 60$\mu\textrm{g}$/$m\ell$ inhibited Cu$^{2+}$-mediated oxidation of LDL almost completely. The electrophoretic mobility of oxidized LDL by addition of daidzin(100$\mu\textrm{g}$/$m\ell$) and puerarin(60$\mu\textrm{g}$/$m\ell$) was faster than that of native LDL, but slower than that of oxidized LDL. The oxidized LDL induced by J774 or macrophage was inhibited strongly in the presence of 100$\mu\textrm{g}$/$m\ell$ daidzin and 60$\mu\textrm{g}$/$m\ell$ Puerarin. The formation of conjugated dienes in the oxidized LDL was strongly inhibited by 100$\mu\textrm{g}$/$m\ell$ daidzin and 60$\mu\textrm{g}$/$m\ell$ puerarin.n.

• Journal of Energy Engineering
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• v.6 no.1
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• pp.77-86
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• 1997

In this study, numerical computations were performed to scrutinize the effect of the size of coal particles on reactive flow fields and concentration distribution of product gases for five cases with four different particle sizes (40 $\mu\textrm{m}$, 60 $\mu\textrm{m}$, 100 $\mu\textrm{m}$, 120 $\mu\textrm{m}$, 140 $\mu\textrm{m}$) in an axisymmetric cylindrical coal gasifier in which Alaska Usibelli subbituminous coals were gasified. Predictions showed that coal particle size affected the concentration distribution of product gases. When coals of 100 $\mu\textrm{m}$ were gasified, the maximum average concentrations of major products, H$_2$and CO, were predicted at the exit of the gasifier. The average mole fractions of CO and H, were shown to be 0.62, and 0.16 (dry basis, inert free), respectively. The cold gas efficiency of 83% was also predicted for the same particle size of 100 $\mu\textrm{m}$.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.521-526
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• 2010

A high-performance liquid chromatography (HPLC) method was established for the determination of fluoroquinolones in milk. Protein was removed by using trichloroacetic acid in order to increase a mean recovery of milk. The extracts were using $Strata^{TM}$-X solid-phase extraction cartridge. The analytes were detected by HPLC on a $C_{18}$ column. HPLC method with fluorescence detection system (Ex: 278 nm, Em: 456 nm) provided a high degree of sensitivity in detecting fluoroquinolones. The limits of quantitation (LOQ) and mean recoveries of fluoroquinolones were 40 ${\mu}g$/kg and 73.6-95.2% (ofloxacin), 10 ${\mu}g$/kg and 77.3-91.9% (norfloxacin), 20 ${\mu}g$/kg and 91.6-94.3% (ciprofloxacin), 10 ${\mu}g$/kg and 81.0-87.8% (enrofloxacin), 10 ${\mu}g$/kg and 71.3-81.0% (sarafloxacin), 10 ${\mu}g$/kg and 89.4-90.8% (orbifloxacin), 2 ${\mu}g$/kg and 69.4-85.5% (danofloxacin).

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1284-1288
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• 2005

The methanol extract of Houttuynia cordata repressed the expression of tyrosinase gene of Bl6 mouse melanoma cell containing tyrosinase promoter. The extract repressed expression of tyrosinase gene by about 13$\%$ and 45$\%$ at 10$\mu$g/mL and 100 $\mu$g/mL, respectively. In the MTT assay, the same extract exhibited very low cytotoxicity at 1$\mu$g/mL, 10$\mu$g/mL, and 100 $\mu$g/mL, respectively. The fractions of ethyl acetate, butyl alcohol, and water did not showed the repressive effect on the expression of tyrosinase gone, but methylene chloride fraction layer repressed highly at 10$\mu$g/mL and 100$\mu$g/mL.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.4
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• pp.47-63
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• 1994

An important parameter in characterizing mobile communication channel is delay spread. This paper presents the results of measured delay profiles and calculated distribution funcations of delay spread for typical cellular service environments at Taejon and vicinities. The measurement system uses 1023 chip length, 5 Mbps PN code and sliding correlation method. It has been evaluated by using commercial hardware channel simulator for reliability of out data. As results the value of mean delay spread is 2.08 $\mu\textrm{s}$for suburban area. 2.12 $\mu\textrm{s}$ for urban area and 1.3 $\mu\textrm{s}$ for national/local road. Delay spread is less then 3.4$\mu\textrm{s}$, 2.8$\mu\textrm{s}$ and 1.5 $\mu\textrm{s}$ for probability of 50% and 4.5$\mu\textrm{s}$, 4.2$\mu\textrm{s}$ and 2.9$\mu\textrm{s}$ for probability of 90% at each tested site. The difference of delay spread is within 7% between going and returning status along same street. In this experiment, we found delay spread for suburban area is larger than reported foreign test results.