• Journal of the Korean institute of surface engineering
• /
• v.51 no.5
• /
• pp.309-315
• /
• 2018

The purpose of this study is to assess the mechanical properties of the ceramic abutment with washer. In this study, ceramic abutment were used, tested with $30^{\circ}$ compression load, shear fatigue, adaptation accuracy test(rotation angle, contact interval), removal torque force test, torsional breaking force test. The $30^{\circ}$ compression load was 729 N, the shear fatigue load was 275 N, adaptation accuracy test of rotation angle was within $3^{\circ}$, contact interval within $10{\mu}m$, and removal torque force test value is $18.88N{\cdot}cm$, torsional breaking force test value is $35.52N{\cdot}cm$. Ceramic abutment with a washer fitted have sufficient mechanical strength and may be substituted for titanium abutment.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.9
• /
• pp.777-782
• /
• 2014

Usually, railway axles are designed for infinite life based on endurance limit of the material and the axle is not fractured immediately when a surface crack initiated. The railway axles have been inspected regularly by NDT such as ultrasonic testing, magnetic testing and eddy current testing and so on. Because the axle failure is profoundly influenced by the probability of missing a fatigue crack during an NDT inspection, it is necessary to evaluate the Non Destructive Interval of railway axle. In the present paper, the Non Destructive Interval of railway axle based on fracture mechanics and finite element analysis was investigated. It was shown that the Non Destructive Interval of railway axle can be evaluated using fracture mechanics approach and extended using NDT which a crack can detect clearly.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.40 no.1
• /
• pp.39-46
• /
• 1991

In the VSS control, the trajectories with a conventional sliding surface have a reaching phase which is an interval from the initial state to the first touching of the sliding surface. Since the sliding mode control can not be realized in a reaching phase, the trajectories may be sensitive to the disturbances and parameter variations. A simple nonlinear sliding surface is proposed to improve the robustness in a reaching phase. The position control of a PM DC servo motor using a new sliding surface is carried out and is compared to the one using the conventional surface. The sliding mode occurs in entire trajectories with the proposed new sliding surface and the improved robustness is obtained.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.35 no.4
• /
• pp.397-403
• /
• 1999

The author examined the response of Amberjacks, Seriola quinqueradiata [TEMMINCI et SCHLIBEL] to the surface attracting lamps (0.5W, 0.8W, 1W) line in the experimental water tank (550 L$\times$58W$\times$73Hcm).The attracting rate was investigated in accordance with the intervals of lighting and putting out hour (1,5 minute) when each of the attracting lamps was gradually switched off after they were switched on all at once. The results are as follows:1. Total distribution rate of fish in the illuminated section was 92.4% (mean 18.5%) in case of 1 minute interval, and 95.8% (mean 19.2%) in case of 5 minutes interva. 2. Mean distribution rate of fish at the illuminated section: Distribution rate at interval of 1 minute were 19.0% in 1W, 18.4% in 0.5W, and 18.0% in 0.8W respectively. distribution rate at interval of 5 minutes were 19.5% in 1W, 19.2% in 0.5 W, and 18.8% in 0.8W respectively.3. Attracting rates of the last section showed very much increasing as illuminating time elapsed, but there was a little difference of attracting rates according to interval and lighting source. 4. Attracting rate of fish in only last section switched on : Attracting rate at interval in case of 1 minute were 97.0% in 1W, 86.0% in 0.8W and 74.0% in 0.5W respectively. Attracting rate at interval in case of 5 minutes were 97.3% in 1W, 90.0% in 0.5W and 88.0% in 0.8W respectively.

• Korean Journal of Optics and Photonics
• /
• v.15 no.1
• /
• pp.51-55
• /
• 2004

Surface plasmons (SPs) are charge density oscillations that propagate along an interface between a dielectric and metal. In this paper, the electric field of SPs and the intereference of two SPs are observed by using Near-field Scanning Optical Microscope (NSOM). The excitation condition of SPs is changed as the optical tip approaches the metal surface, because the excitation condition of SPs is very sensitive to surface structures. To measure the microscope field of SPs, the distance between metal surface and optical tip must contain a specific interval.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.6
• /
• pp.1483-1495
• /
• 1994

A quantitative analysis of a surface roughness for a precision machining of a sculptured surface in milling process is treated under superposition theory in this paper. The geometrical surface rouhgness is calculated as a function of feed per tooth, path interval, radii of tool and cutting edge, and radii of curvatures of workiece. Through machining experiments in a 3-axis machining center, we confirmed the adequacy of the adequacy of the analysis. While cutter mark is neglegible in ball endmilling, it is significant in flat endmilling. When feed per tooth is very small, flat endmilling gives superior finish to ball endmilling. In flat endmilling, cutting condition and cutter path should be strategically chosen to balance the cutter mark height and cusp height.

• Journal of Power System Engineering
• /
• v.6 no.2
• /
• pp.54-59
• /
• 2002

The principle of the FDM(fused deposition modeling) process is based on the layer by layer manufacturing technology, like other RP(rapid prototyping) process. In the FDM process, each layer may have different shape. Therefore, the built model may have stairs shape on its surface. This stairs shape is one of the serious problems in the FDM process. Thus in this study, cube models and spherical models were fabricated by FDM process to investigate the influence of injection amount on surface roughness. Models with various road width were also built to investigate the influence of road width on surface roughness. Surface roughness of the models was measured and analyzed. The result obtained in this study are expected to help selecting the part build orientation for optimum surface roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.04b
• /
• pp.52-57
• /
• 1995

In order to suggest the proper cutting conditions of the CNC milling machining for the free-from surface, some experiments were carried out. In experiments, the influence of cutting conditions on the inclined spherical surface were examined by geometrical anlysis. In thos study, the roundness and cutting force were measured to know the effect of several cutting conditions on the machined surface and the cutting characteristics were carefully investigated. As the result, it was appeared that rigidder tool must be used and the cutting speed must be maintained constantlyfor more effective machining. It can be also known from the experiments that the improved machining surface obtained under about 80 degree, but coarse surface obtained over about 80 degree because of the existance of immproper shape of ball-end mill at the extreme portion.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.10 s.115
• /
• pp.1067-1073
• /
• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.05a
• /
• pp.428-433
• /
• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.