• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.888-892
• /
• 2014

In the design of the rotor of an interior permanent magnet synchronous motor (IPMSM), the bridge between the permanent magnets helps prevent the scattering of permanent magnets and pole pieces during high-speed operation. In the design of a motor, if the bridge is too thick, its performance will be largely degraded because of flux leakage. Additionally, if the bridge is too thin, its mechanical safety cannot be guaranteed. Thus, an accurate analysis method is required to determine the thickness of the bridge. Conventional stress analysis methods determine the thickness of the bridge by only considering the centrifugal force of the rotors. In this study, however, a method that additionally considers the radial force generated by the air-gap flux density based on the conventional methods is proposed and reflected in the design of a traction motor for electric vehicles. Finally, the validity of this study is verified through a reliability test related to high-speed operation.

• Journal of the Korean institute of surface engineering
• /
• v.50 no.5
• /
• pp.380-385
• /
• 2017

Mechanical characteristics of the STS 304 which is heat resistance steel were investigated after artificial aging at $650^{\circ}C$ with 1,000 hours. Tensile test specimens and small test pieces were done artificial aging up to 1,000 hours in the high temperature atmospheric environment. The results present that as the aging time increased, tensile properties were deteriorated. In the case of failure mechanism, the configuration of the fractography presented drastic change from ductile to brittle with aging time. $M_{23}C_6$ carbide leading to the change of the mechanical properties and fracture mode of the aged STS 304 steel continuously precipitated along the grain boundaries of austenite microstructure.

• The KIPS Transactions:PartA
• /
• v.8A no.4
• /
• pp.359-366
• /
• 2001

This paper overviews the design of SANique$^{TM}$ -a shred file system for Linux cluster based on SAN environment. SANique$^{TM}$ has the capability of transferring user data from network-attached SAN disks to client applcations directly without the control of centralized file server system. The paper also presents the characteristics of each SANique$^{TM}$ subsystem: CFM(Cluster File Manager), CVM(Cluster Volume Manager), CLM(Cluster Lock Manager), CBM(Cluster Buffer Manager) and CRM(Cluster Recovery Manager). Under the SANique$^{TM}$ design layout, then, the syndrome of '||'&'||'quot;split-brain'||'&'||'quot; in shared file system environments is described and defined. The work first generalizes and illustrates possible situations in each of which a shared file system environment may split into two or more pieces of separate brain. Finally, the work describes the SANique$^{TM}$ approach to the given "split-brain"problem using SAN disk named "split-brain" and develops the overall recovery procedure of shared file systems.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.388-389
• /
• 2007

Objective of the study is development of 23kV insulating jackets for protection of workers from electrical shock. The breakdown voltage of Ethylene-VinylAcetate copolymers(EVA) films in insulating oil were measured. Insulating jackets were made by the high frequency welding machine, and withstanding voltage test of these were measured. For breakdown voltage at AC 30kV, the number of EVA film with $105{\pm}5{\mu}m$ thickness was 4$\sim$5pieces. When AC 30kV during 3 minutes supplied on the insulating jackets, those were keep on the good quality.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.549-551
• /
• 2003

Satellite images are utilized for various purposes and many people are concerned about them. But it is necessary to process geometric correction for using of satellite images. However, common user regards geometric correction, which is basic preprocessing for satellite image, as laborious job. Therefore we should provide an automatic geometric correction method for Landsat image using GCP chip database. The GCP chip database is the collection of pieces of images with geoinformation and is provided by XML web service. More specifically, XML web service enables common users to easily use our GCP chip database for their own geometric correcting applications.

• 보존과학연구
• /
• s.23
• /
• pp.179-196
• /
• 2002

Sangyangmun is a written record which inform the date, time, history and reason of constructing a wooden building. We have conserved Sangyangmun which was discovered during the repairment and restoration of wooden building. From 1998 to 2002, We have completed the conservation of 27 pieces of 13 cases, for example Daeung-jeon, Bongjeonsa-Temple. First We investigated the material or damage condition of Sangyangmun, and carried out fumigation in order to prevent insects and fungi. Then Sangyangmun must be sealed hermetically using escal film in order to prevent the second damage.

• 보존과학연구
• /
• s.19
• /
• pp.179-191
• /
• 1998

The Dumu of casted iron objects which is the big vessel for the prevention of fire to wood building is conserved in Kyongpok Palace(Dumu sizes：diameter 97cm, height 42cm, thickness 2cm, weight 250kg). The treated objects which some parts were lost, were not corroded, but cracted and broken by an external power, and strongly attached an cement layer on inside surface. First of all cement layer was mechanically removed by pneumatic needle scaler, welded to electric method for broken and cracked pieces, and then the lost sections were restored to use a epoxy resin and glass fiber. In order to prevent a damage during the handling, the restoration section of the inside surface was treated different colour in comparison with original part.

• The Korean Journal of Soil Zoology
• /
• v.7 no.1_2
• /
• pp.29-34
• /
• 2002

Hox genes are a family of regulatory gene encoding transcription factor that primarily play a crucial role during development. Several indications suggest their involvement in the control of cell growth and regenration. RT-PCR and souther blot analysis revealed that labial-like gene was increasingly expressed along a spatial gradient in the anterior region of intact worm. During head and tail regeneration, labial-like gene was expressed only in the head region of regenerating body pieces, suggesting that the gene is involved in the anteroposterior patterning in earth-worm. This result could give us information on the significance of Hox genes and the relationship between Hox genes during regeneration.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.188-191
• /
• 2005

Lower arm for automobile has been made in steel traditionally. Nowadays steel is being substituted fur aluminum to reduce weight of automobile. Widely applied production method of aluminum component has been casting processes or cast/forging processes. But casting or cast/forging processes have limits of application to parts which is required high strength durability like automotive component. In this research, hot forging process has been adopted to produce aluminum lower arm to ensure required mechanical properties. To reduce production cost, 2 pieces with 1 blow process was developed. Optimization and verification of hot forging process for aluminum lower arm was performed by computer aided engineering using finite volume methods.

• Transactions of Materials Processing
• /
• v.23 no.5
• /
• pp.275-281
• /
• 2014

Broaching is widely used for the machining of inner shaped slots in work-pieces. The broach tool is moved vertically (usually by hydraulic power) through the work-piece. Broaching occurs with the work-pieced fix while the broach tool traverses through material and shears it. To produce a T/F driven gear both an outside cutting and an inside cutting are needed. The outside cut determines the tooth profile and the inside cut determines the inner dimension. Broaching can cause problems with concentricity. In the current study, the characteristics of shearing along the cutting blade and the broaching of a T/F driven gear are considered.