• Journal of the Korean Wood Science and Technology
• /
• v.16 no.4
• /
• pp.61-69
• /
• 1988

Recently the automization of wood manufacturing and the development of CNC machine tools becomes the center of interest. Cutting mechanism, tool wear and the roughness of machined surface have been studied. In the studies about wood for special uses, concrete data of cutting is desired. While Pinus densiflora is characterized that heartwood develops as age increases, Chunyang District has the characteristic of strength, red color, relatively regular chap and high heartwood - percentage. But there is no data about cutting this wood, Chunyang District. In this study face milling by sintered carbide tool was excuted to Chunyang District. Cutting force, Surface roughness and states were investigated with regard to cutting speed. Example results were as follows; 1) Mean cutting resistance against lateral component force and longitudinal component force decreased rapidly up to cutting speed of 155 m/min, and remains constant above this speed. 2) The surface roughness of cutting surface lowered as cutting speed increased, regardless of fiber formation. Radial rougness of fiber is larger than lineal surface roughness. 3) Increase in Cutting speed made machining mark restrained. Down-milling showed larger marks than up-milling.

• The korean journal of orthodontics
• /
• v.23 no.4 s.43
• /
• pp.529-541
• /
• 1993

The purpose of this study was to investigate not only the variability in the timing and amount of the maximum pubertal spurt in cranial base and mandible, but also its interrelationship with the timing of peak height velocity. This study was carried out by analysing biannual serial lateral cephalometric radiographs of twenty-six males and twenty-one females who were taken from 8.5years to 16.5years old of mean age, according to the established land-marks and linear measurements. The results of this study were summarized as follows. 1. Prevalance of the maximum growth spurt more than 80 percentage was occurred in all measurements of cranial base and mandible, except posterior cranial base length in the female. 2. In all measurements of cranial base and mandible, the maximum spurt was occurred earlier in the female than the male while it was greater in male in all measurements except ramal height. 3. In body height measurement, the peak height velocity was occurred 2 years earlier for the female(11.0 years old) than the male(13.0 years old). 4. The timing of maximum spurt in anterior cranial base length and total mandibular length in both sexes and ramal height in the female were coincided with PHV. The maximum spurt was occurred in both sexes in all measurements 2 years before or after PHV, except mandibular body length and posterior cranial base length the in female. 5. In all ages, there was significant correlation between the total mandibular length and ramal height, and was also correlation between total cranial base length and anterior cranial base length(P<0.05). However, there was no significant correlation between the ramal height and mandibular body length. In addition, there was also no any correlation between the anterior cranial base length and posterior cranial base length in all ages(P>0.05).

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2016.05a
• /
• pp.20-21
• /
• 2016

Aids to Navigation (AtoN) is marine traffic safety facility to facilitate the safe and efficient movement of shipping and enhance the protection of the marine environment by the regulation or guideline of The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA). By IALA NAVGUIDE, the term "New Danger" is defined as newly discovered hazards not yet shown in nautical documents and includes naturally occurring obstructions such as sandbanks or rocks or man-made dangers such as wrecks. 'New Dangers' should be appropriately marked using Lateral, Cardinal, Isolated Danger marks or by using the Emergency Wreck Marking Buoy. However, the Emergency Wreck Marking Buoy has difficulties with implementation conditions in terms of speed and accuracy to install the buoy. In case of sinking accidents, it is difficult immediately to install the Emergency Wreck Marking Buoy because of weather conditions, marine environments and accident position. This paper studies Auto Releasing New Danger Mark Buoy on the deck which can be automatically to release from the deck of a vessel and float in the water and quickly install the accident position in case of sinking accidents. The buoy will be to reduce the risk of navigation and prevent secondary collisions.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.5
• /
• pp.417-422
• /
• 2016

Aids to Navigation (AtoN) are marine traffic facilities to improve the safety and efficiency of shipping. "New Dangers" should be appropriately marked using lateral, cardinal or isolated danger marks or by using an Emergency Wreck Marking Buoy. However, Emergency Wreck Marking Buoys are difficult to implement in terms of speed and accuracy of installation. In the case of sinking accidents, it is often difficult to immediately install an Emergency Wreck Marking Buoy because of weather conditions, the marine environment or accident positioning. This study concerns Auto-Releasing Emergency Wreck Marking Buoys, which should be installed in all vessel for safe marine navigation and efficient maritime transport with reference to the Maritime Buoyage System (MBS). Auto-Releasing Emergency Wreck Marking Buoys include an auto-release unit, auto reel chain and auto lighting lantern. These buoys can be automatically released from the deck of a vessel and will float in the water for quick installation at the scene of an accident, even in the case of sinking accidents. Auto-Releasing New Mark Buoys are expected to reduce to installation process, prevent secondary accidents by the risk of navigation and be search and rescue rapidly.