• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.32-40
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• 2011

Purpose : The purpose of this study was to investigate the microstructural changes according to aging on the thickness and signal intensity (SI) of the cortical gray matter (GM) and white matter (WM) on the T2-, fluid-attenuated inversion recovery (FLAIR) and T1-weighted MR images in normal subjects. Materials and Methods : The 10, 20, 30, 40, 50, 60, 70, 80 and 90 year age groups of men and women (each 10 individuals) who underwent routine brain MRI, including the T2-, FLAIR and T1-weighted images, were selected for this study. We measured the thickness and the SI of the cortical GM and WM at the postcentral gyrus, which has an even thickness at the level of centrum semiovale, on the axial scans and we calculated the mean values of the thickness ratio of the gray/white matter (TRGW) and the signal intensity ratio of the gray/white matter (SRGW), and we compared the ratios of each age group. Results : On the T2-weighted images, the TRGWs were 0.81 and 0.79 at the age of 10 and they were 0.73 and 0.71 at the age of 90 in the men and women, respectively. So, the GM thickness was decreased more than the WM thickness was with aging. On the FLAIR images, the TRGWs were 1.09 and 1.00 at the age of 10 and they were 1.11 and 0.95 at the age of 70 in the men and women, respectively. On the T1-weighted images, the TRGWs were 0.66 and 0.80 at the age of 10, and the ratio was changed to 0.90 and 0.78 at the age of 90 in the men and women, respectively. On the T2-weighted image, the SRGWs were 1.53 and 1.43 at the age of 10, and they were 1.23 and 1.27 at the age of 90 in the men and women, respectively. On the FLAIR images, the SRGWs were 1.23 and 1.25 at the age of 10 and they were 1.06 and 1.05 at the age of 90 in the men and women, respectively. On the T1-weighted images, the SRGWs were 0.86 and 0.85 at the age of 10, and they were 0.90 and 0.87 at the age of 90 in the men and women, respectively. Conclusion : We suggest that the age-related microstructural changes of the thickness and the SI of the cortical GM and WM on the T2-, FLAIR and T1-weighted images are unique, and so this knowledge will be helpful to differentiate neurodegenerative disease from normal aging of the brain.

• IMMUNE NETWORK
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• v.10 no.6
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• pp.206-211
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• 2010

Background: Dendritic cell (DC)-based tumor vaccine is an attractive modality for the treatment of colon cancer because it has been recurred and produced few side effects in patients. Secretory glycoprotein 90K has been found at elevated level in various cancer tissues and sera. We investigated to establish a more effective DC vaccine for the treatment of colon cancer in which the levels of 90K are elevated. Methods: We obtained the concentrated 90K from 293T cells stably expressing 90K. DCs were cultured from peripheral blood monocytes, and a DC vaccine pulsed with tumor lysate was compared with a DC vaccine pulsed with 90K. We measured the functional activity for CTLs by using IFN-${\gamma}$-enzyme linked immunoabsorbent spot (ELISPOT) assay. Results: DCs pulsed with tumor lysate+90K exhibited the enhanced T cell stimulation, polarization of $\ddot{i}$ T cell toward Th1. The CTLs generated by DCs pulsed with 90K efficiently lysed HCT116 cells. The results indicate that 90K-speicifc-CTLs can recognize 90K proteins naturally presented by colon cancer cells. Conclusion: Our study suggests that 90K-specific CTLs generated by 90K-pulsed DCs could be useful effector cells for immunotherapy in colon cancer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.12
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• pp.1121-1126
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• 2010

This study is to investigate the effects of aromatics and T90 for low cetane number (CN) fuels on combustion and exhaust emissions in low-temperature diesel combustion. We use a 1.9-L common rail direct injection diesel engine at 1500 rpm and 2.6 bar BMEP. Low temperature diesel combustion was achieved via a high external EGR rate and strategic injection control. The tested fuels four sets: the aromatic content was 20% (A20) or 45% (A45) and the T90 temperature was $270^{\circ}C$ (T270) or $340^{\circ}C$ (T340) with CN 30. Given the engine operating conditions, the T90 was the stronger factor on the ignition delay time, resulting in a longer ignition delay time for higher T90 fuels. All the fuels produced nearly zero PM because of the extension of the ignition delay time induced by the low cetane number. The aromatic content was the main factor that affected the NOx and the NOx increased with the aromatic content.

• Bulletin of the Society of Naval Architects of Korea
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• v.25 no.4
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• pp.58-68
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• 1988

This paper is concerned with mechanical properties of unidirectional laminate $[(0^{\circ})_{8T},\;(90^{\circ})_{8T}]$, composed of angle plies $[({\pm}15^{\circ})_{2S},\;({\pm}30^{\circ})_{2S},\;({\pm}45^{\circ})_{2S},\;({\pm}60^{\circ})_{2S},\;({\pm}75^{\circ})_{2S}$ and laminate $[(9^{\circ}/90^{\circ})_{2S},\;(90^{\circ}/{\pm}45^{\circ}/0^{\circ})_S,\;({\pm}45^{\circ}/0^{\circ}/{\pm}90^{\circ})_S,\;({\pm}45^{\circ}/90^{\circ}/0^{\circ})_S,\;(0^{\circ}/90^{\circ}/{\pm}45^{\circ})_S,\;(90^{\circ}/0^{\circ}/{\pm}45^{\circ})_S]$ under the condition of uniform strain tension. Also, experimental investigation was conducted $[10]_{8T}$, off-axis tensile test for intralaminar shear characterization. The experimental data on the failure criterion of tensor polynomial were compared with those from the classical laminate theory. Acoustic Emission experiments have been carried out to investigate the changes of the amplitude distributions of Acoustic Emission monitored during failure of tensile tests on Carbon/Epoxy composites.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.106-112
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• 2016

In this study, circular concrete column specimens confined by carbon sheet tube with different winding angles and different number of carbon sheet plies(3T, 5T and 7T) were tested to propose design equations and a strength reduction factor. Specimens were designed by 300 mm diameter and 600 mm height with $90^{\circ}{\pm}0^{\circ}$, $90^{\circ}{\pm}30^{\circ}$, $90^{\circ}{\pm}45^{\circ}$, $90^{\circ}{\pm}60^{\circ}$, $90^{\circ}{\pm}75^{\circ}$ and $90^{\circ}{\pm}90^{\circ}$ carbon fiber angles. A 10,000 kN UTM was used for compressive strength test of specimens by displacement control method with 0.01 mm/sec velocity. Estimation equations of compressive strength and ultimate strain of circular concrete column specimens confined by carbon sheet tube using a regression analysis and a strength reduction factor to apply ultimate strength design method of concrete were proposed. The strength reduction factor(${\phi}$) of circular concrete columns confined by carbon sheet tube was estimated as 0.64 by the Monte Carlo Analysis Method. Manufacture and construction process have to be perfectly managed by construction managers because the structural capacities of carbon tubes were depends on construction abilities of manufacturing operators.

• Advances in nano research
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• v.10 no.5
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• pp.423-435
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• 2021

This paper examines the thermal post-buckling behaviors of graphene-reinforced metal matrix composite (GRMMC) laminated cylindrical panels which possess in-plane negative Poisson's ratio (NPR) and rest on an elastic foundation. A panel consists of GRMMC layers of piece-wise varying graphene volume fractions to obtain functionally graded (FG) patterns. Based on the MD simulation results, the GRMMCs exhibit in-plane NPR as well as temperature-dependent material properties. The governing equations for the thermal post-buckling of panels are based on the Reddy's third order shear deformation shell theory. The von Karman nonlinear strain-displacement relationship and the elastic foundation are also included. The nonlinear partial differential equations for GRMMC laminated cylindrical panels are solved by means of a singular perturbation technique in associate with a two-step perturbation approach and in the solution process the boundary layer effect is considered. The results of numerical investigations reveal that the thermal post-buckling strength for (0/90)_5T GRMMC laminated cylindrical panels can be enhanced with an FG-X pattern. The thermal post-buckling load-deflection curve of 6-layer (0/90/0)_S and (0/90)_3T panels of FG-X pattern are higher than those of 10-layer (0/90/0/90/0)_S and (0/90)_5T panels of FG-X pattern.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.189-195
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• 2023

This study quantitatively evaluated size selectivity for three netting shapes (T0; regular, T45, T90) and hanging ratio (35%, 70%) of T0 netting used for trawl codend. The size selectivity experiment was performed in a tank using a cube experimental model with a length of 50 cm on one side and 389 experimental individuals, jack mackerel (Trachurus japonicus). In the selectivity analysis, a selectivity curve was created based on the selection ratio using a logistic function, and the 25%, 50%, and 70% selection length and selection range (SR) were obtained. The T0 netting was 19.54 cm when the 50% selective length, which is a selectivity evaluation index, had a hanging ratio of 35%, a selection range of 0.51 cm, and 22.70 cm and 3.08 cm for the hanging ratio of 70%. The T45 netting was 24.34 cm and 2.13 cm, and the T90 netting was 23.51 cm and 2.84 cm. The results of the T45 netting and the T90 netting are similar, and the 50% selection length and selection range were relatively larger than the T0 netting. There was a significant difference in the correlation between the circumference of the inner circle of the mesh by the shape of the netting and the body girth of the experimental individual (Pearson test, r = 0.86, p < 0.05). There was no significant difference in the correlation between the selection ratio by the T0 netting, T45 netting, and T90 netting with a 70% hanging ratio (one-way ANOVA, p > 0.05). The results of this study showed that selectivity such as T45 netting and T90 netting appeared when the hanging ratio, which maximizes the area of T0 netting, was maintained at 70%.

• Textile Coloration and Finishing
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• v.26 no.3
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• pp.151-158
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• 2014

The oil sorption capacities and biodegradability of nonwoven fabrics(pads) of PP and PP/kapok(10/90wt%) blend prepared in this study and commercial pad(T2COM: 100% PP) were compared. The biodegradability(58.5%) of PP/kapok(10/90wt%) blend pad was about 5times higher than those(11%) of PP and T2COM pads after 45days. The oil sorption rates of oil sorbent pads for various oils(diesel, lubricant and Bunker C oils) were markedly increased with increasing dipping time up to about 5min and then levelled off. The oil sorption rate and oil sorption capacity were found to increase in the order of PP/kapok(10/90wt%) blend>PP>commercial(T2COM) and Bunker C>lubricant>diesel.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.67-68
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• 2001

돈분발효퇴와 포도주 부산물의 질소 무기화 및 질산화 과정을 구명하기 위해 시설 내 고추생육시기에 토층별 암모늄태 및 질산태 질소함량을 조사하였다. 질소무기화 및 질산화는 심토층보다 표토층에서 높게 나타났다. 생육전반에 걸쳐 총 질소 무기화 및 질산화율은 처리간에 다양하였지만, 전반적으로 총 질소 무기화는 정식후 90일 까지 증가하였지만 그 이후로는 감소하였다. 표토층에 있어 최고 질소 무기화 및 질산화는 정식후 90일에 T4(포도주부산물 400kg/10a＋돈분발효퇴비 1,000kg/10a)에서 관측되었다. 가장 높은 질소 무기화는 정식후 30일에 대조구에서 272.5mg/kg과 정식 후 90일에 T4(포도주부산물 400kg/10a＋돈분발효퇴비 1,000kg/10a)에서 843.4mg/kg으로 나타났다. 또한 질산화는 T4(포도주부산물 400kg/10a＋돈분발효퇴비 1,000kg/10a)에서 정식 후 90일에 872.2mg/kg으로 가장 높게 나타났다. 15-30cm 토층의 질산화 현상은 질소 무기화와는 다르게 나타났는데 질소 무기화는 대체로 90일에 증가한 반면 질산화는 90일에 감소하는 경향을 나타내었다. 마지막 조사시기인 정식 후 180일에는 급격히 감소하는 현상을 보였는데 고추 생육에 따라 양분 흡수로 암모늄태질소 및 질산태질소가 감소되었다. 0-15cm 토층, 15-30cm 토층의 질소무기화 및 질산화에서 T4(포도주부산물 400kg/10a＋돈분발효퇴비 1,000kg/10a)의 15-30cm 토층 질산화가 낮게 나타났다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.371-377
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• 2011

The aim of this study is to investigate the effects of aromatics and T90 temperature for high cetane number (CN) of diesel fuels on combustion and exhaust emissions in low-temperature diesel combustion in a 1.9 L common rail direct injection diesel engine at 1500 rpm and 2.6 bar BMEP. Four sets of fuels with CN 55, aromatic content of 20% or 45% (vol. %), and T90 temperature of $270^{\circ}C$ or $340^{\circ}C$ were tested. Given engine operating conditions, all the fuels showed the same tendency of decrease of PM with an increase of an ignition delay time. At the same ignition delay time, the fuels with high T90 produced higher PM. At the same MFB50% location the amount of NOx was similar for all the fuels. Furthermore, at the same ignition delay time the amounts of THC and CO were similar as well for all the fuels. The amount of THC and CO increased with an extension of the ignition delay time mainly because of the increase of fuel-air over-mixing.