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권원태 대한기계학회 1994 대한기계학회논문집 Vol.18 No.2
The resultant cutting force during machining with a worn tool is viewed as a decomposition of the cutting force into a cutting force component related to chip removal from the workpiece and into a component dependent on the contact force between the tool flank's wear land and the workpiece. The shear line method, in which the cutting force is considered proportional to the length of the shear line, is used to calculate the cutting force component for the removal of the chip, while the elastic effect of the workmaterial on the tool is taken into consideration to analyze the effect of tool flank wear. The predicted resultant cutting force, expressed as the sum of both components, is compared to experimental data obtained during wave-on-wave cutting.
SiC-$Si_3N_4$ 세라믹 절삭공구의 미세구조 및 절삭특성
권원태,김영욱,Gwon, Won-Tae,Kim, Yeong-Uk 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.12
Four SiC-Si$_3$N$_4$ceramic cutting tools with different composition have been fabricated by hot-pressing. Correlations among the annealing time, the corresponding microstructure and the mechanical properties of resulting ceramics have been investigated. The fracture toughness and the grain size of both SiC and Si$_3$N$_4$in SiC-Si$_3$N$_4$composites increased with the annealing time. 1\`he hardness of SiC-Si$_3$N$_4$composites was relatively independent of the grain size and the sintered density. These ceramic cutting tools were tested under various cutting conditions and compared with the commercial Si$_3$N$_4$ceramic cutting tools. The experimental results were compared in terms of tool life and cutting force. The performance of SiC-Si$_3$N$_4$ceramic cutting tool shows the possibility to be a new ceramic tool.
권원태 한국기상학회 2005 Asia-Pacific Journal of Atmospheric Sciences Vol.41 No.2/1
The global-mean surface temperature has risen by 0.6oC during the 20th century due to the increase of atmospheric concentrations of greenhouse gases (IPCC, 2001a), and the mean temperature of the Korean Peninsula is also risen by 1.5oC during the same period due to global warming as well as rapid urbanization. During the 21st century, the global-mean temperature is projected to rise 1.4-5.8oC associated with the various scenarios from IPCC Special Report on Emission Scenario (SRES) (2000). Reduction in emissions and atmospheric concentrations of greenhouse gases will be very likely to mitigate the degree and likelihood of global warming. However, if the greenhouse gas concentrations were fixed at present level, the global-mean temperature and sea level would continue to rise due to thermal inertia of global climate system. Climate change resulting from increased greenhouse gas concentrations has the potential to harm human societies and natural ecosystems, such as agriculture, forestry, water resources, human health, coastal settlements, and land and ocean ecosystems, which will need to adapt to a changing climate or face adverse impacts. We propose a nation-wide network of research centers from diverse disciplines to study integrated impact assessment of climate change and to develop adaptation measures in Korea.