• KIEAE Journal
• /
• v.10 no.5
• /
• pp.165-170
• /
• 2010

Super high-rise mixed use buildings require a longer period for construction. Especially finishing work takes up about 40% of the whole construction period. Thus, finishing work is becoming an important factor in determining the construction period along with earth work and frame work. As the expected returns added by the reduction of the period and cost in constructing super high-rise mixed use buildings are huge, the expectations are now increasing for the possible gains. In this respect, as the period of finishing work is easier to be shortened than that of frame work, the efforts to acquire the technical knowledge to reduce the finishing work period are now being required. Accordingly, in this study, we aimed at suggesting the basic data for designing an economic plan for finishing-work procedure by analyzing the productivity of each work type of finishing work procedure on the basis of the execution and results of a construction method as a time-flexible finishing work plan. For this, we categorized the work types of finishing work procedure into each work unit and provided a work-system for each of them. Also, with case studies, we calculated the detailed amounts of the work-loads, required materials, productivity, and productivity index of the main work types of finishing work procedure and each of their separate work units as well as analyzed the relationship between the value results to suggest a better way to improve its productivity.

• Design & Manufacturing
• /
• v.12 no.2
• /
• pp.16-21
• /
• 2018

Recently, as the demand for high-precision parts increases due to industrial development, a machine tool system for ultra-precision machining and polishing has been actively developed. As a result, there is an increasing demand for ultra-precision surface roughness along with dimensional processing. However, due to the increase in processing time due to the demand for ultra-precise surfaces and enormous facility investment, it is difficult to secure competitiveness. The polishing process using the abrasive film in super precision machining has been applied to machines, electronic devices, aerospace, and medical fields. Super finishing using the abrasive film which is applied in the industrial field recently can achieve high surface roughness in a short time. Super finishing using the abrasive film which is applied in the industrial field recently can achieve high surface roughness in a short time. Also, application of industrial field is increasing due to advantages such as low noise and low dust. Recently, researches on stainless steel having strong resistance to corrosion, heat resistance, heat resistance, toughness and weldability have been actively conducted with respect to the nuclear energy industry or marine development. Therefore, in this study, surface roughness and residual stress were measured after SUS304 polishing using dynamic analysis of film polishing apparatus and polishing film.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2002.05a
• /
• pp.39-39
• /
• 2002

In order to improve wear and fatigue resistance of the structural materials, especially cold work roller for 304 stainless steel, an eco-super-finishing and surface hardening treatment using ultrasonic vibration energy was developed and applied to the SKD-ll roller. The eco-super-finishing machine was designed and fabricated by DesignMecha Co, by its own technology. It was observed that the surface roughness, hardness and residual stress were changed from $Ra{\;}={\;}O.25\mu\textrm{m}$, Hv=710 and ${\sigma}$={\;}+400{\;}MPa{\;}to{\;}Ra{\;}={\;}0.165\mu\textrm{m}$, Hv = 1200 and ${\sigma}=-610$ MPa after 20 KHz micro-cold forging, which means almost equal to the 300 % improvement of life-time.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1995.04a
• /
• pp.36-41
• /
• 1995

Recently, as the problems according to the deteriorated structure were gathering sterength, there were required the advent of the high peformance for polymer ceme at compostie in building constrution devision. The polymer cement mortar was developed for improvements of the various problems in ordinary cement mortar. finishing method using the super flowing polymer-based self levelling mortar for concrete slab and floor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.8
• /
• pp.501-504
• /
• 2014

This paper was developed and described core-process to implement low on resistance which was the most important characteristics of SJ (super junction) MOSFET. Firstly, using process-simulation, SJ MOSFET optimal structure was set and developed its process flow chart by repeated simulation. Following process flow, gate level process was performed. And source and drain level process was similar to genral planar MOSFET, so the process was the same as the general planar MOSFET. And then to develop deep trench process which was main process of the whole process, after finishing photo mask process, we developed deep trench process. We expected that developed process was necessary to develop SJ MOSFET for automobile semiconductor.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.291-292
• /
• 2010

• Textile Coloration and Finishing
• /
• v.27 no.1
• /
• pp.11-17
• /
• 2015

Recently, super fiber reinforced composite materials are widely used in many industries due to high mechanical properties. In this study, 2 different types of composite materials were manufactured in order to compare their mechanical properties. Carbon and Aramid fibers were used for reinforcement materials and Bisphenol-A type epoxy resin was for matrix. Two kinds of fiber-reinforced materials were manufactured by RIM(Resin Injection Molding) method. Before manufacturing composite materials, the optimal manufacturing and curing process condition were established and the ratio of reinforcement to epoxy resin was discussed. FT-IR analysis was conducted to clarify the structure of epoxy resin. Thermal and mechanical property test were also carried out. The cross-section of composite materials was observed using a scanning electron microscope(SEM).

• Textile Coloration and Finishing
• /
• v.21 no.1
• /
• pp.30-37
• /
• 2009

Studies on plants such as lotus leaf suggested that dual-scale structure could contribute to super-hydrophobicity. We introduced super-hydrophobicity onto poly(ethylene terephthalate)(PET) fabric with dual-scale structure by assembling $TiO_2$ nano sol. PET fabric was treated with $TiO_2$ sol, water-repellent agent using various parameters such as particle size, concentration. Morphological changes by particle size were observed using field emmission scanning electron microscopy(FE-SEM) and AFM measurement, contact angle measurement equipment. The contact angle of water was about 138.5$^{\circ}$, 125.8$^{\circ}$, 125.5$^{\circ}$ and 108.9$^{\circ}$ for PET fabric coated with 60.2nm, 120.1nm, 200nm and 410.5nm $TiO_2$ particles, compared with about 111.5$^{\circ}$ for PET fabric coated with water repellent. When we mixed particle sizes of 60.2nm and 120.1nm by 7:3 volume ratio, the contact angle of water was about 132.5$^{\circ}$. And we mixed particle sizes of 60.2nm and 200nm by 7:3 volume ratio, the contact angle of water was about 141.8$^{\circ}$. Also we mixed particle sizes of 60.2nm and 410.5nm by 7:3 volume ratio, the best super-hydrophobicity was obtained. In this paper, we fabricated various surface structures to the water-repellent surfaces by using four types of $TiO_2$ nano-particles, and we found that the nanoscale structure was very important for the super-hydrophobicity.

• Textile Coloration and Finishing
• /
• v.21 no.6
• /
• pp.1-11
• /
• 2009

Super-hydrophobic surface, with a water contact angle greater than $150^{\circ}$, has a self cleaning effect termed 'lotus effect'. We introduced super-hydrophobicity onto aramid/rayon mixture fabric with dual-scale structure by assembling silica nano-sol. Mixture fabric was treated with silica nano-sol, fluoric polymer using various parameters such as particle size, concentration. Silica nano-sol size were measured using particle size analyzer. Morphological changes by particle size were observed using field emission scanning electron microscopy(FE-SEM), contact angle measurement equipment. The contact angle of water was about $134.0^{\circ}$, $137.0^{\circ}$, $143.0^{\circ}$, $139.5^{\circ}$ and $139.0^{\circ}$ for mixture fabric coated with 100.2nm, 313.7nm, 558.2nm, 628.5nm and 965.4nm silica nano-sol, compared with about $120.0^{\circ}$ for mixture fabric coated with fluoric polymer. When we mixed particle sizes of 100.2nm and 558.2nm by 7:3 volume ratio, the contact angle of water was about $146.2^{\circ}$. And we mixed particle sizes of 313.7nm and 558.2nm by 7:3 volume ratio, the contact angle of water was about $141.8^{\circ}$. Also we mixed particle sizes of 558.2nm and 965.4nm by 7:3 volume ratio, the best super-hydrophobicity was obtained. In this paper, we fabricated the water-repellent surfaces with various surface structures by using four types of silica nano-sol, and we found that the dual-scale structure was very important for the super-hydrophobicity.

• Journal of the Korean Society of Safety
• /
• v.17 no.3
• /
• pp.30-35
• /
• 2002

The magnetic abrasive polishing is the useful method to finish using magnetic power of a magnet. It's not a long time this method was introduced to korea as one of precision finishing techniques. The magnetic abrasive polishing method is not so common for machine that it is not spreaded widely. The are rarely researcher in this field because of no-effectiveness of magnetic abrasive. The mechanism of this R&D is dealing with the dynamic state of magnet-abusive. This paper deals with mediocritizing magnetic polishing device into regular lathe and this experiment was conducted in order to get the best surface roughness at low cost. We need to continue the research on it. This paper contains the result of experiment to acquire the best surface roughness, not using the high-cost polishing material in processing. The average diameters of magnetic abrasive are the particles of 150$\mu\textrm{m}$, 250$\mu\textrm{m}$.