• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.127-133
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• 1991

Acoustic microscopy has attracted much intrest recently as potential mondestructive evalution technique for detecting and sizing defects of surface and sub-surface. Also acoustic emission testing method has been developed for detecting microcracks which is more than 30 umm in length quintitatively on ceramics material. In the present paper, acoustic emission during the four point bending test in hot-pressed sintered Si$\_$3/N$\_$4/ specimen which was stressed bythermal shock has been measured by high sensitive sensing system. The surface and sub-surface cracks were detected by scanning acoustic microscope of 800 MHz and conventional ultrasonic testing in C-scope image. The purpose was to investigate the location and size of cracks by SAM and AE technique, whose experimental datas demontrates good agreement for detecting microcracks.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.119-129
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• 2002

On the process of cross-media color reproduction, a key feature is the use of gamut mapping techniques to adjust the different color gamuts between displays and printers. Even though a nunber of gamut mapping algorithms were published in the past, only limited colorimetric evaluation of them has been carried out to date. In this paper, the multi-anchor points clipping method(MAPC) was proposed as a new gamut mapping algorithm compensating the defects of the current algorithms such as nearest point clipping method(NPC), centroid clipping method(SLIN), straight clipping method(LLIN) and maximum chroma clipping method(CUSP).

• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.18-26
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• 1992

A mechanical-hydraulic hitch control system has been adapted to most agricultural tractors. But it has various defects due to friction, inertia and hysteresis. Recently a number of electronic-hydraulic hitch control systems have been developed in several countries to improve control performance of the agricultural tractors equipped with a mechanical-hydraulic hitch control system. This study was conducted to develop a new electronic-hydraulic hitch control system using an electro-hydraulic servo valve instead of an on-off valve and to carry out computer simulation of the system. According to the result of computer simulation, the control system showed the best performance when the proportional constants were 9 and 4 for position and draft control respectively. The step and frequency responses were improved as flow rate increased.

• Particle and aerosol research
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• v.5 no.3
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• pp.95-109
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• 2009

A low temperature plasma process has been widely used for semiconductor fabrication and can also be applied for the preparation of solar cell, MEMS or NEMS, but they are notorious in the point of particle contamination. The nano-sized particles can be generated in the low temperature plasma process and they can induce several serious defects on the performance and quality of microelectronic devices and also on the cost of final products. For the preparation of high quality thin films of high efficiency by the low temperature plasma process, it is desirable to increase the deposition rate of thin films with reducing the particle contamination in the plasmas. In this paper, we introduced the studies on the generation and growth of nanoparticles in the low temperature plasmas and tried to introduce the recent interesting studies on nanoparticle generation in the plasma reactors.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.441-446
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• 2003

The chemical mechanical polishing (CMP) process is now widely employed in the ultra large scale integrated (ULSI) semiconductor fabrication. Especially, shallow trench isolation (STI) has become a key isolation scheme for sub-0.13/0.10${\mu}{\textrm}{m}$ CMOS technology. The most important issues of STI-CMP is to decrease the various defects such as nitride residue, dishing, and tom oxide. To solve these problems, in this paper, we studied the planarization characteristics using slurry additive with the high selectivity between $SiO_2$ and $Si_3$$N_4$ films for the purpose of process simplification and in-situ end point detection. As our experimental results, it was possible to achieve a global planarization and STI-CMP process could be dramatically simplified. Also, we estimated the reliability through the repeated tests with the optimized process conditions in order to identify the reproducibility of STI-CMP process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.147-150
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• 2002

In this study, we evaluated the dilute HF Cleaning to reduce residual defects made by W CMP process. But, One point we should focus is It should not effect to metal thin film reliability. The purpose of this test is to verify barrier metal damage during HF cleaning and based on this result we get rid of slurry residue defect which is main defect of W CMP process for the better yield.

• Journal of the Korea Safety Management & Science
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• v.8 no.1
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• pp.27-42
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• 2006

Considering in view of China's low price and Japan's high technology, the most important point is the quality of product. To increase the comparative power internationally all workingmen have to fulfill the responsibility to maximize the quality, and this is possible practiced under 'Zero Defect' spirit. To reduce the defect ratio to 'Zero' the workingmen have to recognize own fault, all the manufacturing process should be conducted under 'Fool Proof System', If done under this circumstances, then labor force can work comfortably and safely without nervousness and tiresome. The productivity and quality can increase ultimately and even foreign labor, imbecile child, old-aged labor can participate in work, which can reduce shortage of labor source. Therefore, in this study all defects in manufacturing process, it would be recognized the errors and mistakes caused by human.

• Proceedings of the Safety Management and Science Conference
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• 2009.11a
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• pp.61-71
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• 2009

Since 1995, the small and medium enterprise introduced the Quality Innovation Program that is called 100PPM Quality Renovation Program. A point of 2000, the program's name was changed by Single PPM Quality Innovation Program in pursuit of defects below 10ppm in outgoing quality. Nowaday 1,651 companies is received Single PPM Quality Certification from government at the end of 2008. On the other side, the return or withdrawal of certification is going on because of various reasons. In this study, we analyse the status of certification's preservation and cancellation, and suggest the cooperation ideas between government and companies.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.25-36
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• 1994

The sheet metal forming process is one of the most important manufacturing processes in the modern industry. From the view point of mechanics involved, it is very difficult to predict whether a newly designed sheet metal part can be formed without defects such as fracture, wrinkling and surface unevenness, etc. In order to reduce the effort taken in the trial-and-error process and to control the process effectively, a systematic method for process modeling is to required. The aim of sheet forming simulation through the process modeling is to reduce the lead time for die disign and manufacture by process modeling is to reduce the lead time for die design and manufacture by means of investigating the deformation mechanics and the mutual interaction between the process parameters. In this paper, the necessity, the present status, and the future technology about CAE of sheet forming simulation have been discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.669-675
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• 1997

This paper investigates the performances of GFRP bar and its possibility for using a substitute of steel bar. GFRO bar was made with introducing the glass fiber into GTR added UPE. We carried out the tensile test of GFRP and steel bar and out the three point bend test bond-test and fracture energy measurement on the GFRP bar and steel bar reinforced concrete. The GFRP bar was excellent as comparison with steel bar in the contribution to the energy absorption and the ductility of concrete. But its tensile, bond and bend strengthes were comparatively small. In order to improve these defects, we judged that glass fibers in GFRP bar must be completely adhesive one another by the impregnating glass fibers into UPE.