• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.10C
• /
• pp.1395-1401
• /
• 2004

In The objective of this paper is to apply blind minimum output energy multiuser detection method to multicarrier direct sequence code division multiple access system. The performance of MC/DS-CDMA is reduced due to multiple access. To increase the performance of system, we need to cancel multiple user components. Blind interference canceller is able to detect the desired's information with the only minimal information of the desired user. We evaluate the performance of the proposed receiver under Gaussian channel. Simulation results show that the proposed receiver has about 6［dB］ gain of signal to noise ratio without multiple user interference and has about 3［dB］ gain of SNR with multiple user interference. Also, the result of comparing the capacity of the active users shows that the proposed method has about 2 times capacity more than conventional method. As a conclusion, simulation results show that the proposed method has better performs better than conventional method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2009.10a
• /
• pp.54-55
• /
• 2009

The bandwidth of detecting radars used for military purpose is increasingly broadened, and recently, the frequency band of the detecting radars is expanding to millimeterwave bands c! the millimeterwave bands of 35 GHz and 94 GHz. Since, especially, it is essential and important to fabricate and develop EM wave absorber with the absorption ability more than 10 dB in 94 GHz band, the EM wave absorber was manufactured based on the design method by FDTD simulation As a result, the developed EM wave absorber with the composition ratio of Binder(CPE with additional materials) : Carbon = 70 : 30 wt.% has the thickness of 0.7 mm and the absorption ability more than 14 dB in the frequency range of 94 GHz.

• Journal of Surface Science and Engineering
• /
• v.36 no.4
• /
• pp.296-300
• /
• 2003

Extended cylindrical magnetron sputtering system with rotating 600-mm long and 90-mm diameter graphite cathode and pulsed power supply voltage generator were developed and fabricated. Time-dependent Langmuir probe characteristics as well as carbon films thickness were measured. It was shown that ratio of ions flux to carbon atoms flux for pulsed magnetron discharge mode was equal to $\Phi_{i}$ $\Phi$sub C/ = 0.2. It did not depend on the discharge current in the range of $I_{d}$ / = 10∼60 A since both the plasma density and the film deposition rate were found approximately proportional to the discharge current. In spite of this fact carbon film structure was found to be strongly dependent on the discharge current. Grain size increased from 100 nm at $I_{d}$ = 10∼20 A to 500 nm at $I_{d}$ = 40∼60 A. To deposit fine-grained hard nanocrystalline or amorphous carbon coating current regime with $I_{d}$ = 20 A was chosen. Pulsed negative bias voltage ($\tau$= 40 ${\mu}\textrm{s}$, $U_{b}$ = 0∼10 ㎸) synchronized with magnetron discharge pulses was applied to a substrate and voltage of $U_{b}$ = 3.4 ㎸ was shown to be optimum for a hard carbon film deposition. Lower voltages were not sufficient for amorphization of a growing graphite film, while higher voltages led to excessive ion bombardment and effects of recrystalization and graphitization.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.69-72
• /
• 2018

A new silkworm variety 'Chilseongjam' was bred for special purpose as educational learning and festivals. Their breeding history and major characteristics are as follows. The Chilseongjam variety was selected and succeeded from the F1 of Galwon ${\times}$ C721 in 2009 autumn. They are showing 94% (spring & autumn) of high practical hatching ratio. The larval period of Chilseongjam (spring: 23 d, autumn: 24 d 3 h) was shorter than that of Daebakjam (spring: 24 d, autumn: 25 d 23 h). In the pupation percentage, Chilseongjam (spring: 96.6%, autumn: 86.1%) is similar to Daebakjam Daebakjam (spring: 96.3%) in spring, but autumn is lower than Daebakjam (autumn: 94.9%). Single cocoon weight (spring: 1.57 g, autumn: 1.29 g) and Cocoon yield (spring: 14.2 kg, autumn: 11.1 kg) were lower than those of Daebakjam (spring: 2.76 g, 25.4 kg, autumn: 2.19g, 20.2 kg), respectively. The new silkworm variety, Chilseongjam showed higher pupation rate than control variety. This variety can be used as a educational learning and festivals.

• Nutrition Research and Practice
• /
• v.13 no.3
• /
• pp.205-213
• /
• 2019

BACKGROUND/OBJECTIVES: Myocardial infarction (MI) is caused by extensive myocardial damage attributed to the occlusion of coronary arteries. Our previous study in a rat model of ischemia/reperfusion (I/R) demonstrated that administration of arabinoxylan (AX), comprising arabinose and xylose, protects against myocardial injury. In this study, we undertook to investigate whether psyllium seed husk (PSH), a safe dietary fiber containing a high level of AX (> 50%), also imparts protection against myocardial injury in the same rat model. MATERIALS/METHODS: Rats were fed diets supplemented with PSH (1, 10, or 100 mg/kg/d) for 3 d. The rats were then subjected to 30 min ischemia through ligation of the left anterior descending coronary artery, followed by 3 h reperfusion through release of the ligation. The hearts were harvested and cut into four slices. To assess infarct size (IS), an index representing heart damage, the slices were stained with 2,3,5-triphenyltetrazolium chloride (TTC). To elucidate underlying mechanisms, Western blotting was performed for the slices. RESULTS: Supplementation with 10 or 100 mg/kg/d of PSH significantly reduces the IS. PSH supplementation (100 mg/kg/d) tends to reduce caspase-3 generation and increase BCL-2/BAX ratio. PSH supplementation also upregulates the expression of nuclear factor erythroid 2-related factor 2 (NRF2), and its target genes including antioxidant enzymes such as glutathione S-transferase mu 2 (GSTM2) and superoxide dismutase 2 (SOD2). PSH supplementation upregulates some sirtuins ($NAD^+$-dependent deacetylases) including SIRT5 (a mitochondrial sirtuin) and SIRT6 and SIRT7 (nuclear sirtuins). Finally, PSH supplementation upregulates the expression of protein kinase A (PKA), and increases phosphorylated cAMP response element-binding protein (CREB) (pCREB), a target protein of PKA. CONCLUSIONS: The results from this study indicate that PSH consumption reduces myocardial I/R injury in rats by inhibiting the apoptotic cascades through modulation of gene expression of several genes located upstream of apoptosis. Therefore, we believe that PSH can be developed as a functional food that would be beneficial in the prevention of MI.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.12
• /
• pp.33-40
• /
• 2008

The load distribution and deformation of rock-socketed drilled shafts subjected to axial loads are evaluated by a load-transfer method. The emphasis is on quantifying the effect of coupled soil resistance in rock-socketed drilled shafts using the 2D elasto-plastic finite element analysis. Slippage and shear load transfer behavior at the pile-soil interface are investigated by using a user-subroutine interface model (FRlC). It is shown that the coupled soil resistance provides the influence of pile toe settlement as the shaft resistance is increased to an ultimate limit state. The results show that the coupling effect is closely related to the value of pile diameter over rock mass modulus (D/$E_{mass}$) and the ratio of total shaft resistance against total applied load ($R_s$/Q). Through comparisons with field case studies, the 2D numerical analysis reseanably presented load transfer of pile and coupling effect due to the transfer of shaft shear loading, and thus represents a significant improvement in the prediction of load deflections of drilled shafts.

• Korean Journal of Ecology and Environment
• /
• v.35 no.1 s.97
• /
• pp.28-35
• /
• 2002

The effect of physical parameters on water quality was analyzed using monitoring data of 193 agricultural reservoirs. The retention time of reservoirs ($t_d$) ranged between 10 and 140 days, and the ratio of drainage area (DA) to reservoir surface area (SA) was between 10 and 120. Both ratios of DA/SA and total area (TA)/ reservoir storage (ST) in Korean agricultural reservoirs were relatively greater than those in natural lakes in other countries. As retention time was plotted against DA/SA ratio, it was shorter in Korean reservoirs than natural lakes. The semi-logarithmic relationship between TA/SA and t>$t_d$ was $t_d\;=\;42.21(TA/ST)^{-1}$ (n = 50, $R^2\;=\;0.89$). While areal loading of total phosphorus (TP) was below $4\;gTP{\cdot}m^{-2}{\cdot}yr^{-1}$ in general, it exceeded $10\;gTP{\cdot}m^{-2}{\cdot}yr^{-1}$ in reservoirs where DA/SA ratio was greater than 100, which implies that areal loading of TP increases as DA/SA ratio increases. Chl-a concentration was positively related with the mean depth of reservoir, implying the higher Chl-a concentration with deeper the mean depth. Therefore, the deeper reservoir might be advantageous in water quality management perspective if other morphological conditions are similar. The empirical regression equation using physical parameters was also suggested in the estimation of TP concentration in the reservoirs. Combined information presented in this paper might be applicable to the water quality management in agricultural reservoirs.

• Journal of Bio-Environment Control
• /
• v.4 no.2
• /
• pp.136-143
• /
• 1995

Using a PEG- dextran two phase partition method, plasma and intracellular membrane separated from microsomal membrane of canola (Brassica napus) leaves have been fractionated by centrifugation. $K^{+}$- ATPase specific activity in the plasma membrane (U$_2$ phase) of plants grown at $25^{\circ}C$ and 1$0^{\circ}C$ were 6.6 and 4.6 times, respectively that of the microsomal membrane. Plasma membrane had a lower cytochrome- c- oxidase specific activity than the microsomal membrane or intracellular membrane, while intracellular membrane (L$_2$ phase) had a high cytochrome-c- oxidase but little $K^{+}$- ATPase specific activity. The plasma membrane of canola grown at 1$0^{\circ}C$ had higher 18:3 to 18:2 (linolenic to linoleic acid) ratio (29.2% ) and higher degree of unsaturation than that grown at $25^{\circ}C$ The double bond index of plasma membrane from canola grown at 1$0^{\circ}C$ increased by 8.9% relative to canola grown at $25^{\circ}C$. Similar, intracellular membrane increased by 19.7% at 1$0^{\circ}C$. Canola grown at 1$0^{\circ}C$ was lower in chlorophyll contents (17.3%) than that grown at $25^{\circ}C$. These changes in fatty acid unsaturation were attributable largely to change in Cl8 fatty acid, with major changes occurring in linolenic acid (18 :3) which might have a physiological role of membrane to adaptation on low temperature.ure.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2002.11a
• /
• pp.171-184
• /
• 2002

Approx. 200,000 bpd vacuum residue oil is produced from oil refineries in Korea. These are supplying to use asphalt, high sulfur fuel oil, and upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435-500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER(Korea Institute of Energy Research) are studing on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature : 1,100~1,25$0^{\circ}C$, reaction pressure : 1~6kg/$\textrm{cm}^2$G, oxygen/V.R ratio : 0.8~0.9 and steam/V.R ratio : 0.4-0.5. Experimental results show the syngas composition(CO+H$_2$) : 85~93%, syngas flow rate : 50~110Mm$^3$/hr, heating value : 2,300~3,000 ㎉/Nm$^3$, carbon conversion : 65~92, cold gas efficiency : 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.

• Journal of Energy Engineering
• /
• v.12 no.1
• /
• pp.49-57
• /
• 2003

Approx. 200.000 bpd vacuum residue oil is produced from oil refineries in Korea, and is supplied to use asphalt, high sulfur fuel oil and for upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however its high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435~500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER (Korea Institute of Energy Research) are studying on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature: 1.100~l,25$0^{\circ}C$, reaction pressure: 1~6 kg/$\textrm{cm}^2$G, oxygen/V.R ratio: 0.8~0.9 and steam/V.R ratio: 0.4~0.5. Experimental results show the syngas composition (CO+H$_2$): 85~93%, syngas flow rate: 50~l10 Nm$^3$/hr, heating value: 2,300~3,000 k㎈/Nm$^3$, carbon conversion: 65~92, cold gas efficiency: 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.