• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.593-596
• /
• 1992

An evaluation method for the effective length of electromagnet - which bas U-shape in frontview and trapezoidal in side view - is presented. Using 2D FEM, 2 analysing models are introduced for calculating effective length of the magnet ; the front model is using the normalized equi-pole face area of the magnet and the side model using the normalized equi-magnetic circuit. The ratio of the effective length to the length of bottom plate (core) comes out 1.25 - 1.30. In addition, 3D FEM analysis has been done and a proto-type test model is manufactured to verify the analysing method. The ratio by the experiment appears 1.2, which is reasonably in good agreement with the suggested numerical results.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.232-235
• /
• 1995

A side-extrusion model, meant for deeper understanding of the material flow in the CONFORM (continuous extrusion forming) of trub shaped aluminum profiles is presented. In order to get the desirded straight shape of the extrudate,every part of its cross-section must exit the die with the same velocity. Problem is assumed by plane strain UBET-model to analyze it in a simplified way. This has been done by studying the side-extrusion through a two -hole die face. The flow is balanced by determining the optimum lengths of the bearing lands, i.e., those lengths which result in equal exit velocities of the extrudates. Furthermore, the material flow, as influenced by the punch velocity, has been investigated.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.04a
• /
• pp.77-82
• /
• 1998

The Part of slot on rotary compressor which plays an important part of the reliability and performance is studied on machinability and the wear characteristics for the specimen made by sand mold and permanent mold. The experiment are used the face cutter of milling machine which make the processing surface like broaching process and rollblock wear test machine. Permanent-mold casting iron is not affected by variation of RPM of milling machine, but sand-mold cast-iron is improved to increasing RPM. Also sand-mold casting iron shows superior wear characteristic to permanent-mold casting iron. This results from harder matrix of pearlite structure and self-lubrication characteristics of graphite. And wear particles in tested oil show shape and size similar to severe wear particles of oil taken from rotary compressor. The material and surface condition of slot play important part of the reliability and performance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.49-52
• /
• 2001

Moire topography method is a well-known non-contacting 3-D measurement method. Recently, the automatic 3-D measurement by moire topography has been required since the method was frequently applied to the engineering and medical fields. 3-D measurement using projection moire topogrphy is very attractive because of it s high measuring speed and high sensitivity. In this paper, using two-wavelength method of projection moire topography tested to measuring object with the $2\pi$-ambiguity problem. Experimental results prove that the proposed scheme is capable of finding absolute fringe orders, so that the $2\pi$-ambiguity problem can be effectively overcome so as to treat large step discontinuities in measured objects.

• The Journal of the Korean dental association
• /
• v.10 no.6
• /
• pp.379-383
• /
• 1972

Patient, S.B. moon, an 20-years old female was first seen S.N.U. Dental Hospital in January 1971 because of masticatory dysfunction, cosmetic unfiguration due to mandibular micrognathia. Her Complaint was 'bird face' due to under development of the jaw. A bilateral Z-shape sliding osteotomy was performed with the patient under the general Anesthesia.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.3
• /
• pp.585-594
• /
• 2003

Clinical observation on the diseases of Jang(臟) and Bu(腑) comes to the conclusions as follows: Variation in Jang(臟) and Bu(腑) exists diversely with every man because man is a microcosmos resembling the great universe, 'Mother Nature'. If the patient has a distinctive features of Jang(臟) and Bu(腑) in configuration, the diseas must be caused by the problems of Jang(臟) and Bu(腑). Distinctive features of Jang(臟) and Bu(腑) can be recognized by the shape and color of face, ear, eye, mouth and nose. Distinctive features of Jang(臟) and Bu(腑) should be examined preferentially when it comes to old people, children and persons who have past record of surgical operation on Jang(臟) and Bu(腑) organs.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.927-931
• /
• 1997

In process of the finish face milling of the hardended STD11 steel(H /sab r/ c50,55) by CBN tool, the optimum tool shape is suggested,which can minimize the tool fracture and by chipping by impact. The obtained results are as follows. (1) The optimal chamfer angel was about 25 .deg. , and the suitable chamfer width was 0.2mm. (2) The nose radius of tool was most excellent at 1.2mm in the viewpoint of tool wear and surface roughness. (3) Wear speed was effected by sintering method of CBN tool B.U.E

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.5 no.3
• /
• pp.58-65
• /
• 1996

This thesis is concerned with the study on the characteristics of the cutting resistance occurring in finish machining of hardened steels such as carbon tool steel and alloy tool steel by a ceramic tool with nose radius. For the purpose, the shape of cutting cross-section made at nose part of the tool was analyzed geometrically and the wear mechanism on the flank face of the ceramic tool is investigated. In order to investigate the characteristics of cutting resistance two categories of cutting conditions are suggested, along with geometrical analysis. One category includes the conventional cutting parameters such as feed and depth of cut, another containing new cutting parameters of thickness of cut and width of cut etc. Thickness of cut width of cut and area of undeformed chip section formed by the condition of engagement between workpiece and cutting tool are determined as the function of feed, depth of cut and nose radius of cutting too, And an effective approach angle is determined by depth of cut and nose radius.

• Nuclear Engineering and Technology
• /
• v.44 no.8
• /
• pp.847-854
• /
• 2012

Despite extensive research efforts, the mechanism of the nucleate boiling phenomena is still not clear. A direct numerical simulation of the boiling phenomena is one of the promising approaches in order to clarify its heat transfer characteristics and discuss their mechanism. Therefore, many DNS procedures have been developed based on recent highly advancing computer technologies. This brief review focuses on the state of the art in direct numerical simulation of the pool boiling phenomena over the past two decades. In this review, the fundamentals of the boiling phenomena and the bubble departure and micro-layer models are briefly introduced, and then the numerical procedures for tracking or capturing interface/surface shape such as the front tracking method, level set method, volume of fluid treatments, and other methods (Lattice Boltzmann method, phase-field method and so on) are briefly reviewed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.759-762
• /
• 2000

In order to reduce lead-time and cost, recently the technology of Rapid Prototyping and Manufacturing (PR/M) has been used widely. So various RP/M methods have been developed and these systems commercialized several years ago. But we have carried out rapid product, such as sphere, by the milling process instead of RP system. in the case of sphere with three-dimensional shape. the machining method using conventional milling machine has resulted in some troubles because of its deformation and lack of stiffness which is due to usual work piece set up method. In this paper, the feasibility of milling process which is divided into two steps such as the-upper-and-1ower-face milling process using supporting material were investigated and suggested.