• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.119-123
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• 2002

In this study, we discussed the characteristics of breakdown and surface flashover of FRP in L$N_2$ for applying it to spacer of a superconducting power equipment. Fiberglass reinforced plastic(FRP) has high breakdown puncture strength and has high mechanical strength. So the research of its dielectric properties have been conducted in liquid nitrogen($LN_2$). We measured breakdown voltage of FRP and distinguished four types of surface flashover along solid insulator with arrangement of electrodes and measured the surface flashover voltages of each types of electrode arrangement. The type of a electrode set at the back of the insulator showed the worst dielectric property. The property of surface flashover depending on pressure was tested.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.657-660
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• 2009

The surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ cathode particle was modified by lanthanum based oxide to improve electrochemical property and thermal stability. The XRD pattern of surface layer was indexed with that of $La_4NiLiO_8$. The discharge capacity of modified electrode was higher than that of pristine sample, specially at fast charge-discharge rate and high cut-off voltage. In the DSC profile of the charged sample, the generation of heat by exothermic reaction was decreased by surface modification. Such enhancement may by attributed to the presence of stable lanthanum based oxide, which effectively suppressd the reaction between electrode and electrolyte on the surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.519-522
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• 2000

The correlation of surface morphology and magnetic property of NiFe thin films on Si(001) deposited by RF-magnetron sputter has been investigated, using AFM, XRD and MR measurements. During short field annealing for 15 min, there was no significant change in XRD patterns of NiFe thin films. However, the degree of surface roughness was changed with increasing annealing temperature. With variation of surface roughness, there was significant difference in MR characteristics of NiFe thin films. In the case of as-deposited NiFe thin films(T$\_$G/ = 150$^{\circ}C$) and UFA400 (T$\_$A/ = 400$^{\circ}C$) having smooth surface, good linearity of MR Curve was observed.

• Corrosion Science and Technology
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• v.4 no.2
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• pp.39-44
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• 2005

The purpose of this work is to understand the effect of Mo addition on SSC susceptibility of high strength low alloy steels in terms of microstructure and corrosion property. Materials used in this study are high strength low alloy (HSLA) steels with carbon content of 0.04wt% and Mo content varying from 0.1 to 0.3wt%. The corrosion property of steels was evaluated by immersion test in NACE-TM01-77 solution A and by analyzing the growth behavior of surface corrosion products. SSC resistance of steels was evaluated using constant load test. Electrochemical test was performed to investigate initial corrosion rate. Addition of Mo increased corrosion rate of steels by enhancing the porosity of surface corrosion products. However, corrosion rate was not directly related to SSC susceptibility of steels.

• Textile Coloration and Finishing
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• v.10 no.1
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• pp.43-50
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• 1998

In order to investigate the effect of contained impurities of polyester fiber fabric on the scouring and dyeing property, 3 kinds of polyester fabrics were heat-set treated at $160-200^\circ{C}$ and evaluated its scouring and dyeing property by through with soxhlet extraction and K/S value of the dyed fabric derived from the surface reflectance. The impurities such as oiling and sizing agent are adhered more strongly on the polyester fabric surface by heat setting temperature. In scouring test, the removal of the these re-adhered impurities on the polyester fabric is very difficult in comparing with unheat-set treated polyester fabric. It is also confirmed that the remained impurities on the polyester fiber decreased its dyeing property.

• KIEAE Journal
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• v.9 no.2
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• pp.65-71
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• 2009

Results from tests for what mixing rate of soil and sand is proper for the rammed earth and for how much additives are optimum are as under. 1) In the test to evaluate what mixing rate of soil and sand is desirable, peptizing property and surface sticking rate are found similar in its degree, but compression strength is found most stable when the ratio of soil and sand mixing shows 30:70 which indicates the best mixing rate of soil and sand. 2) In a test to add hydrated lime, compression strength, peptizing property, and surface sticking rate are found best when the mixing rate of soil and sand shows 23:7. 3) In a test to add sea weeds, the peptizing property goes down at 75% of sea weeds input a little bit more than at 100%, but compression strength shows best at 75% which is thought to be the best rate. 4) In a drop test, more soil powder mixed, the sticking strength gets better and more sands are contained, the sticking strength gets far worse to be scattered in powder type. 5) As concluding all results mentioned in the above item, the most desirable mixing rate of soil, sand, and hydrated lime is found to be 23:7:70 for the rammed earth where compression strength, peptizing property, and surface sticking rate are best.

• Journal of the Korean institute of surface engineering
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• v.32 no.1
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• pp.61-66
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• 1999

The Spin-dependent tunneling magnetoresistance (TMR) effect was observed in $NiFe/Al_2O_3$/Co thin films. The samples were prepared by magnetron sputtering in a system with a base pressure of $3\times10^{-6}$Torr. the insulating $Al_2O_3$layer was prepared by r.f. plasma oxydation method of a metallic Al layer. The ferromagnetic and insulating layers were deposited through metallic masks to produce the cross pattern form. The junction has an active area of $0.3\times0.3\textrm{mm}^2$ and the $Al_2O_3$layer is deposited through a circular mask with a diameter of 1mm. It is very important that insulating layer is formed very thinly and uniformly in tunneling junction. The ferromagnetic layer was fabricated in optimum conditions and the surface of that was very flat, which was observed by AFM. Tunneling junction was confirmed through nonlinear I-V curve. $NiFe/Al_2O_3$/Co junction was observed for magnetization behavior and magnetoresistance property and magnetoresistance property is dependent on magnetization behavior and magnetoresistance property and magnetoresistance property is dependent on magnetization behavior of t재 ferromagnetic layer. The maximum magnetoresistance ratio was about 6.5%.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.41-45
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• 2010

This study was performed to evaluate the effect of paper property changes by internal addition of surface strength agent on printability. Advances in printing technique has required the development of paper qualities in many aspects. Basically paper structure is composed of hydrogen bonds which induce many problems in high speed printing machine because of weak bonding strength. One of the important printing problems is surface picking when mechanical pulp or recycled pulp are used. It was caused by the ink-stained blanket in printing process because accumulations of pollutant in white water and other elements which are bonded weakly or do not have hydrogen bonds. Debris at paper surface adheres to blanket which deteriorates printing efficiency and causes various problems. To complement these problems, Pennocel 5137 of polysaccharide structure was used as an agent to improve paper's surface property, strength and printability. Paper surface picking was analyzed by RI-1 test. As the dosage amount increased tensile strength, fiber bonding strength and ZDT strength were improved. Further more formation, smoothness and surface picking resistance were improved. It was confirmed that when adding polysaccharide structure polymers to improve surface strength such as surface picking resistance, it was also possible to improve tensile strength, fiber bonding strength, formation and smoothness.

• Fashion & Textile Research Journal
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• v.14 no.2
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• pp.277-285
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• 2012

This research studied how to develop tight upper sportswear from 3D scan data considering fabric stretch property. Subjects were five Korean men of average figure in their 20's. Scanning was done for ten postures via vitus smart/pro(Techmath LTD). Analyzing from 3D scan data, more than 70% of the upper body surface showed surface change rate under 20%. It was shoulder and under arm side part that showed most noticeable body surface change when moving. A parametric model with convex surface was generated and flattened onto the plane, resulting 2D pattern. The error rate occurring in the process of 3D to 2D conversion was 0.2% for outline and 0.13% for area, respectively. Thirteen kinds of stretchable fabrics in the market were collected for this study. Stretch property was in the range of 16.0~58.2% for wale direction; 23.1~78.4% for course. Based on wear trial test, four fabrics were chosen for making the 1st experimental garment and finally one fabric was chosen for the 2nd one, which was developed applying 4 kinds of crosswise reduction rate on 2D pattern: 0, 5, 10, and 15%. Through wear trial test and garment pressure measurement, experimental garment applied with 10% pattern reduction rate was evaluated as most comfortable and considerable.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.217-220
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• 2014

We studied the plating properties of Sn-Pb solder according to the shape of the Cu wire's cross-section for photovoltaic ribbon. The thickness of the Sn-Pb layer largely decreased to 29% on a curved Cu surface, compared to a flat Cu surface. This phenomenon is caused by the geometrical decrease in the contact angle of the liquid Sn-Pb solder and an increase in the surface energy of the solid/vapor on the curved Cu surface. We suggest a new ribbon's design where the Cu wire's cross-section is a semi-ellipse. These semi-ellipse ribbons can decrease the use of Sn-Pb solder to 64% and increase the photovoltaic efficiency, by reducing the contact area between the ribbon and cell, to 84%. We also see an improvement of reflectivity in the curved surface.