• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.769-777
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• 2003

The strengthening of concrete structures in situ with externally bonded carbon fiber is increasingly being used for repair and rehabilitation of existing structures. Because carbon fiber is attractive for this application due to its good tensile strength, resistances to corrosion, and low weight. Generally bond strength and behavior between concrete and carbon fiber mesh(CFM) is very important, because of enhancing bond of CFM. Therefore if bond strength is sufficient, it will be expect to enhance reinforcement effect. Unless sufficient, expect not to enhance reinforcement effect, because of occuring bond failure between concrete and CFM. In this study, the bond strength and load-displacement response of CFM to the concrete by the direct pull-out test(the tensile-shear test method) were investigated using the experiment and the finite element method analysis with ABAQUS. The key variables of the experiment are the location of clip, number of clips and thickness of cover mortar. The general results indicate that the clip anchorage technique for increasing bond strength with CFM appear to be effective to maintain the good post-failure behavior.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.77-85
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• 2004

To evaluate the effect of plasma cleaning on the soldering reliability the plasma cleaning using Ar-10vol%$H_2$ gas was applied on a UBM(Under Bump Metallization). The UBM consisted of Au/ Cu/ Ni/ Al layers which were deposited on a Si-wafer with 20 nm/ 4 $\mu\textrm{m}$/ 4 $\mu\textrm{m}$/ 0.4 $\mu\textrm{m}$ thickness respectively. Sn-3.5%Ag, Sn-3.5%Ag-0.7%Cu and Sn-37%Pb solder balls sized of 500 $\mu\textrm{m}$ in diameter were used. Solder balls on the UBM were plasma reflowed under Ar-10%$H_2$ plasma (with or without plasma cleaning). They were compared with air reflowed solder balls with flux. The spreading ratios of plasma reflowed solder with plasma cleaning was 20-40% higher than that of plasma reflowed solder without plasma cleaning. The shear strength of plasma reflowed solder with plasma cleaning was about 58-65MPa. It showed 60-80% higher than that of plasma reflowed solder without plasma cleaning and 15-35% higher than that of air reflowed solder. Thus it was believed that plasma cleaning for the UBM using Ar-10vol%$H_2$ gas was considerably effective for the improvement of the strength of solder ball.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.49-57
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• 2007

Au-Sn solder alloy were deposited in multilayer and co-sputtered film by rf-magnetron sputter and the composition control and analysis were studied. For the alloy deposition condition, each components of Au or Sn were deposited separately. On the basis of pure Sn and Au deposition, the deposition condition for Au-Sn solder alloy were set up. As variables, the substrate temperature, the rf-power, and the thickness ratio were used for the optimum composition. For multilayer solder alloy, the roughness and the composition of solder alloy were controlled more accurately at the higher substrate temperature. In contrast, for co-sputtered solder, the substrate temperature influenced little to the composition, but the composition could be controlled easily by rf-power. In addition, the co-sputtered solder film mostly consisted of intermetallic compound, which formed during deposition. The compound were confirmed by XRD. Without flux during bonding of solder alloy film on leadframe, the adhesion strength were measured. The maximum shear stress was $330(N/mm^2)$ for multilayer solder with Au 10wt% and $460(N/mm^2)$ for co-sputtered solder with Au 5wt%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.997-1006
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• 2010

For manufacturing modern cars, so-called multi-materials, such as aluminum alloy with high-strength steels, are used. For obtaining such materials, a new joining method is required to achieve the multi-material design. Mechanical clinching is one of joining methods used to join the dissimilar materials. The objective of this study is to investigate the characteristics of mechanical clinching of Al5052 alloy to high-strength steels (SPFC440, 590, 780). Using FE-analysis and clinching experiment, the joinability of Al5052 alloy to high-strength steel is evaluated by geometrical shape of mechanical clinched joint, such as neck-thickness and undercut. Further, the joint strength is evaluated by performing a single-lap shear test. The upper high-strength steel SPFC780 was not clinched because of the necking of the upper sheet. The joint strength increased with increasing strength of the upper sheet. For the lower high-strength steel sheet, the joinability and joint strength decreased with increasing strength of the lower sheet.

• Korean journal of food and cookery science
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• v.22 no.3 s.93
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• pp.379-385
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• 2006

The purpose of this study was to investigate the effects of immersion period after tumbling on the physicochemical properties of boiled pork loin with soy sauce. After the samples were tumbled for 30 min with soy sauce (1.5% salt concentration), they were immersed for 1, 5 or 10 days. Boiled pork loin was cooked at an internal temperature to $75^{\circ}C$. Cooking yields of boiled pork loin were significantly increased with increasing immersion period. The reduction in diameter and thickness for pork loin were significantly decreased with increasing immersion period, but moisture content and water holding capacity were increased. Shear force in the immersed samples after tumbling was significantly lower than in the control. In sensory evaluation color, flavor, texture, and juiciness of boiled pork loin immersed after tumbling should higher ratings than those of control.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.756-762
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• 2011

This study was conducted to investigate the effects of moisture content on microbiological stability and texture characteristic of dry-cured ham. The moisture content of dry-cured hams was adjusted to 35% (C) or 45% (T) and then vacuumpackaged after slicing to a 1 inch thickness. All packaged dry-cured hams were stored at $10^{\circ}C$ for 3 mon, and physicochemical analyses and a sensory evaluation were conducted to verify the quality of dry-cured hams during four different storage periods. Moisture content was significantly higher in T (44.89%) compared to that in C (35.03%). However, crude fat content was higher in C (14.08%) than that in T (11.11%). The pH, salinity, and shear force were higher in C than those in T, and dry-cured hams derived from C seemed to provide low lipid oxidation stability during storage. In contrast, T showed high CIE $L^*$, CIE $a^*$ and CIE $b^*$, and aw values when compared to dry-cured hams from C. Total plate counts and Lactobacillus tended to increase with the increase in storage period, and both were lower in T than those in C after 1 mon of storage. Our results indicate that 45% moisture content improved dry-cured ham quality as compared to that of dry-cured hams containing 35% moisture.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.336-342
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• 1999

Various surface treatment techniques can be applied onto the surface of carbon fibers to increase interlaminar shear strength (ILSS). In a commerciaI treatment, first, surface of carbon fiber was oxidized, after that, a sizing agent was coated to improve handleability and adhesion to the matrix. Carbon fiber reinforced composites (CFRC) which is made of these fibers show excellent ILSS but show low vaIues of impact strength In this study, reactive and ductile interphase was introduced between fiber and matrix to increase both the ILSS and impact strength. By using electric conductivity of carbon fibers, flexible polymers which have ionizable group, i.e., MVEMA and EMA, were coated onto the surface (oxidized) of carbon fiber by the technique of electrodeposition. ILSS and impact strength of composites were evaluated according to the surface treatments, i.e., commercial sizing treatment, interphase introduction, and without sizing treatment. Izod impact strength and ILSS of CFRC were simultaneously improved in thc thickness range of $0.08{\sim}0.12{\mu}m$ of MVEMA interphase. Water resistance of the composites was decreased by introducing MVEMA interphase.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.544-553
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• 2018

This study was conducted to determine the effects of breed and sex on meat quality and sensory properties of the loin in three-way crossbred pigs: $Landrace{\times}Yorkshire{\times}Duroc$ (LYD) and $Landrace{\times}Yorkshire{\times}Woori$ (LYW) black pig synthesized by Korean native breed. Carcass traits did not differ by breed. Carcass weight and backfat thickness were higher in castrates than in gilts (p<0.01). LYW showed significant high values in fat content, cooking loss, and water-holding capacity (WHC) than LYD (p<0.05). Redness and yellowness of the meat were higher in LYW than in LYD (p<0.01). Further, LYW had lower pH and shear force than LYD (p<0.001). Significant high scores in color and flavor were obtained in LYW or gilts compared to LYD or castrates by sensory panel, respectively (p<0.05). However, other sensory traits did not differ by breed or sex. Capric acid (C10:0) was higher in LYD than LYW (p<0.001). However, stearic acid (C18:0) and saturated fatty acid (SFA) contents were higher in LYW than LYD (p<0.05). Eicosenoic acid (C20:2) and the n6/n3 ratio were higher in gilts than in castrates, whereas SFA content was higher in castrates than in gilts. These results suggest that certain physicochemical qualities of meat and sensory properties are improved in LYW compared to LYD. This study could provide basic data on meat quality of crossbred pigs with Woori black pig as a terminal sire.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.575-583
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• 2009

As the height of buildings rises, new structural systems are being applied other than theexisting S, RC, and SRC to decrease the weight of buildings and to make their construction more efficient, CFT structureshad been applied in many building construction projects due to their superior structural performance and construction efficiency. CFT structures need a diaphragm to harmoniously transmit the beam flange load to the column and the opponent beam in connections. Especially, on the right and left sides of the column other beams are connected, The establishment of a diaphragm for the lower part flange load delivery of the beam and guarantee for concrete filing capacity difficulty have (What does this mean?). In this paper, connection details are proposed in the form of a welded vertical plate with a circular hole on the CFT column's interior to harmoniously transmit the lower-part beam flange load to the column and the opponent beam. Thesediaphragm details use the concrete anchor effect in the beam flange load delivery, with the concrete-filled CFT column interior piercing the hole of the perforated plate, and a perforated board is established vertically to improve the concrete filling capacity. To analyze the structural performance of the proposed connection details, five simple tension specimens were made with the following parameters: with our without vertical and horizontal perforated plates, shear hole number, concrete filled or not, thickness of the perforated plate, etc. Then experimental tests were performed on these specimens.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.601-613
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• 2007

It is reported that factors affecting the behavior of reinforced earth retaining walls built on soft ground are not only basic physical properties but also the increase of load by the reinforced earth retaining walls, consolidation period, pore water pressure, etc. This study analyzed the behavior of reinforced earth retaining walls and soft ground using SAGE CRISP, a ground analysis program. First, we examined the effect of the replacement method, which was to prevent the excessive displacement of reinforced earth retaining walls, in improving the behavior of the walls. Second, we compared and analyzed how the behavior of ground is affected by the vertical interval of stiffeners on the back of reinforced earth retaining walls after the application of the replacement method. Lastly, we proposed the optimal replacement width and depth in the application of the replacement method. The results of this study proved that the replacement method is considerably effective in improving the behavior of reinforced earth retaining walls. In addition, the vertical interval of stiffeners on the back of reinforced earth retaining walls appeared effective in improving the horizontal displacement of the top of retaining walls but not much effective in improving the vertical displacement of the back of retaining walls. In addition, improvement in horizontal-vertical displacement resulting from the increase in replacement width was not significant and this suggests that the increase of replacement width is not necessary. With regard to an adequate replacement depth, we proposed the ratio of replacement depth to the height of retaining walls(D/H) according to the ratio of the thickness of the soft layer to the height of retaining walls(H/T).