• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.7
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• pp.987-994
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• 2000

Cotton fabrics were finished with mixture of BTCA and silicone by pad-dry-cure process to achieve better mechanical properties than those of finished with BTCA alone. The changes of mechanical properties o( finished cotton fabrics were measured with by the KES-FB System and the hand values were calculated from the data of mechanical properties. With the durable press finish with BTCA tensile, bending, shear and compression properties increased. In hand values, Stiffness Crispness and Anti-Drape Stiffness increased, and Fullness & Softness decreased. Whereas silicone treatment reduced bending and shear properties and improved tensile and compressional resilience. Thus, Stiffness Crispness and Anti-Drape Stiffness decreased, and Fullness & Softness increased. These results indicated that BTCA treatment restricts fiber/yarn mobility in the fabric structure due to crosslinking, but silicone treatment reduces inter-fiber and inter-yarn frictional forces. Therefore, finish with mixture of BTCA and silicone provided cotton fabrics with a lower Stiffness, Crispness and Anti-Drape Stiffness and a higher Fullness & Softnesss than finish with BTCA alone.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.215-222
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• 2007

Coating of Hot-dip galvannealed steel consists of various Fe-Zn intermetallic compounds. Since the coating is hard and there for is very brittle, the surface of steel sheet is easy to be ruptured during second manufacturing processing. This is called as powdering. In addition, forming equipment might be polluted with debris by powdering. Therefore, various research have been carried out to prohibit powdering fur improving the quality of GA steel. This paper carried out finite element analysis combined with damage model which simulate the failure of local layer of hot-dip galvannealed steel surface during v-bending test. Since the mechanical property of intermetallic compound was unknown exactly, we used the properties calculated from measurements. The specimen was divided into substrate, coating layer and interface layer. Local failure at coating layer or interface layer was simulated when elemental strain reached a prescribed strain.

• Journal of the Korean Home Economics Association
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• v.30 no.1
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• pp.35-47
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• 1992

The objective of this research was to determine whether the pressure on the cylinder by stretch fabric could be related by the size of cylinder, the amount of extension, and the properties of the fabric. The results were as follows : 1. There were linear relationships between the pressure of the fabric exerts on the cylinder and percentage of extension of the fabric, the radius of the cylinder, the tensile stress of the fabric, and the bending and shearing properties of the fabric. 2. From the results above, 4 regression equations from which the pressure could be estimated were derived by regression analysis. The equations were as follows : 1) P=a/Rb 2) P=c＋ds 3) P=e＋fSt 4) P=g＋hB P : Pressure, R : Radius of cylinder, S : Percentage of Stretch, St : Tensile stress, B : Bending property.

• Journal of Ship and Ocean Technology
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• v.7 no.3
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• pp.56-65
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• 2003

The hull monitoring systems of container ships with four long-base gages give enough information for identifying the hull girder loads such as bending and torsional moments. But such a load-identification for container ships has not been known. In this paper, a load-identification method is suggested in terms of a linear matrix equation that the measured strain vector equals to the multiplication of the transformation matrix and the desired strain component vector. The equation is proved to be mathematically complete by the property of positive-definite determinant of the transformation matrix. The method is applied to a hull stress monitoring system for 8100TED container ship during sea trial, and the estimated external loads illustrate reasonable results in comparison with the pre-estimated results. This moment decomposition concept has also been tested in real operation conditions. The typical phenomena over the Suez Canal illustrated very suitable results comparing with the physical understandings. Henceforth, one can effectively use the proposed concept to monitor the hull girder loads such as bending and torsional moments.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.459-460
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• 2006

N-type $Bi_2Te_3-Sb_2Te_3$ solid solutions doped with 1$CdCl_2$ was prepared by melt spinning, crushing and vacuum sintering processes. Microstructure, bending strength and thermoelectric property were investigated as a function of the doping quantity from 0.03wt.% to 0.10wt.% and sintering temperature from $400^{\circ}C$ to $500^{\circ}C$, and finally compared with those of conventionally fabricated alloys. The alloy showed a good structural homogeneity as well as bending strength of $3.88Kgf/mm^2$. The highest thermoelectric figure of merit was obtained by doping 0.03wt.% and sintering at $500^{\circ}C$.

• Journal of Powder Materials
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• v.7 no.3
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• pp.131-136
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• 2000

The effect of tempering temperature on the three point bending fatigue behavior of a P/M high speed steel JYPS-23 (1.28% C, 4.20% Cr, 6.40% W, 5.00% Mo, 3.10% V, bal. Fe) was investigated. The number of cycles to failure of the specimen austenitized at $1175^{\circ}C$ drastically increased with increasing tempering temperature. As tempering temperature increased from 500 to $620^{\circ}C$, the volume fraction and average size of carbides (MC or M6C) did not significantly changed, while hardness decreased drastically. The reduced hardness is due to the softening of matrix, which increased the resistance of the fatigue crack propagation. For a practical application, powder compacting test were also conducted with the P/M high speed steel punches tempered at 500, 580, and $620^{\circ}C$. The number of compacting cycles to failure of the punches also increased with increasing tempering temperature.

• Advances in nano research
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• v.12 no.1
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• pp.37-47
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• 2022

In this paper, the non-linear static analysis of Timoshenko nanobeams consisting of bi-directional functionally graded material (BFGM) with immovable ends is investigated. The scratching in the FG nanobeam mid-plane, is the source of nonlinearity of the bending problems. The nonlocal theory is used to investigate the non-linear static deflection of nanobeam. In order to simplify the formulation, the problem formulas is derived according to the physical middle surface. The Hamilton principle is employed to determine governing partial differential equations as well as boundary conditions. Moreover, the differential quadrature method (DQM) and direct iterative method are applied to solve governing equations. Present results for non-linear static deflection were compared with previously published results in order to validate the present formulation. The impacts of the nonlocal factors, beam length and material property gradient on the non-linear static deflection of BFG nanobeams are investigated. It is observed that these parameters are vital in the value of the non-linear static deflection of the BFG nanobeam.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.26-37
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• 2012

Recently, the demand and supply on the Hanok have been increased. However, Hanok should be requested larger section of structural members because of excessive roof weight. So, structural skin-timber was manufactured to get a lightweight structural member. The structural skin-timber has exterior shape with larger section but a great volume of wood be removed. The reduced strength of structural skin-timber can be supplemented by hybridizaion of structural member. Japanese larch and Domestic pine were used to manufacture the structural skin-timber. Structural skin-timbers of rectangular shape and cylinder shape were manufactured and tested to evaluate the bending properties. The intended strength property could not be obtained because member had been suffered severe damage by precision deficiency of manufacturing machine. However, if precision of manufacturing machine would be improved and additional hybridizaion of structural skin-timber would be done, lightweight structural member will be able to be manufactured. Structural skin-timber did not showed statistical significancy between two species, so it is possible to use pine mixed with larch. Only MOR of larch showed statistical significancy between rectangular shape and cylinder shape, so it is necessary to use of those as separate things. However, the rest of skin-timber can be judged mixed using because of non statistical significancy. The objective of this study was the development of lightweight larger structural member with relatively strength. If hybrid member of skin-timber could be developed with wood-ceramics, lightweight steel and more, it can be possible to be used as a building material of Hanok, interior material, post & beam construction material and more.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.486-496
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• 2018

This study was conducted to confirm an effect of span length on bending properties of larch dimensional lumber in the four point bending test. The size of specimen in this study was 38 (width) ${\times}$ 89 (depth) ${\times}$ 3,600 (length) $mm^3$, and average air-dry density and moisture content of the specimens was $543.5kg/m^3$ and 10.5%, respectively. Visually graded No. 1 dimensional lumbers of 248 were divided by two groups to compare modulus of rupture (MOR) and modulus of elasticity (MOE). One group was tested in the four point bending test with span length of 1,650 mm, and other was tested with span length of 3,000 mm. While MOE was not different according to span length in 5% significance level, MOR was different in accordance with span lengths and was in inverse proportion to change of span length. Fifth percentiles of MOR in span length of 1,650 and 3,000 mm were 28.65 and 25.70 MPa, respectively. It was confirmed that the difference between MORs in each case increased as normalized rank increased. This is because of size effect in Weibull weakest link failure theory. Therefore, KS F 2150, in which there is only regulation about span to depth ratio of 15 or more, is needed to be revised to contain a method considering size effect for MOR. From the method, various results of bending test with different size of lumber could be used to determine design value of lumber.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.2
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• pp.41-47
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• 2010

The effect of PCB and BGA pad designs was investigated on the mechanical property of Pb-free solder joints. The mechanical property of solder joint was tested by three different test methods of drop impact tests, bending impact test, and high speed shear test. Two kinds of pad design such as NSMD (Non-Solder Mask Defined) and SMD (Solder Mask Defined) were applied with the OSP finished Pb-free solder (Sn-3.0Ag-0.5Cu, Sn-1.2Ag-0.5Cu). in the drop impact test and bending impact test, the characterized lifetime showed the same tendency, and SMD design showed better mechanical property of solder joint than NSMD regardless of test method, which was due to the different crack path. The fracture crack on SMD pad was propagated along the intermetallic compound (IMC) layer of solder joint, while the fracture crack on NSMD pad propagated through upper edge of land which shields pattern. In the high speed shear test, pad lift occurred on the solder joint of NSMD. SMD/SMD combination of pad design consequently illustrated the best mechanical property of BGA/PCB solder joint, followed by SMD/NSMD, NSMD/SMD, and NSMD/NSMD.