• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.499-500
• /
• 2006

With the capability of net shaping for complex 3D geometry, powder injection molding (PIM) is widely used for automotive parts, electronics and medical industry. In this study, an ultrasonic dental scaler tip produced by machining process was redesigned for the PIM process. An injection mold was designed and machined to produce the dental scaler tip by the PIM process.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.183-185
• /
• 2003

Spatially referenced mobile mapping (MM) images contain rich information of man-made objects , e.g. road centerlines, buildings, light poles, traffic signs ,billboards and line trees etc. Therefore, the applications in transportation, urban 3D reconstruction, utility management are implemented increasingly. It’s a fundamental issue lies in MM image process that how to orient this image in the object space including interior orientation of camera and the exterior orientation of image. In this paper, the algorithm of automatic acquirement of DC (Digital Camera) parameters based on MM images is illustrated. And then, the mapping between image space and object space for MM images is described.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.270-274
• /
• 2005

The capability of net shaping for complex 3-D geometry, powder injection molding(PIM) is widely used for parts in the field of automotives, electronics and medical industry. Powder injection mold design for dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip. Product design and mold design for dental scaler tip was presented. Short shot experiment with scaler tip PIM mold and several defect (flash etc.) during injection molding process was discussed.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.372-372
• /
• 2010

We have investigated adsorption of selenophene on Si(100) at room temperature using high resolution photoemission spectroscopy (HRPES) and near edge X-ray absorption fine structure (NEXAFS) in the partial electron yield (PEY) mode. The Si 2p, C 1s, Se 3d spectra of selenophene on Si(100) show that selenophene is nondissociatively chemisorbed on Si(100)-$2{\times}1$ through [2+2] cycloaddition. NEXAFS has been conducted to characterize the adsorption geometry of selenophene on Si(100). Since the $\pi^*$ orbital of C=C bond show good angular dependence in carbon K-edge NEXAFS spectra, the angle $53{\pm}5^{\circ}$ determined from NEXAFS spectra. This majority structure is consistent with the [2+2] cycloaddition of selenophene to the dimer of the Si(100)-$2{\times}1$ surface.

• Advances in Computational Design
• /
• v.5 no.1
• /
• pp.13-34
• /
• 2020

As small size and complex metal machining components demand increases, cutting processes in microscale become necessary. Ball-end milling is a commonly used finishing process, which nowadays can be applied in the microscale size. Surface quality and dimensional accuracy are two basic parameters that affect small size components in their assembly and functionality. Thus, good quality can be achieved by optimizing the cutting conditions of the procedure. This study presents a 3D simulation model of ball-end milling in microscale developed in a commercial CAD software and its optical and computing results. These carried out results are resumed to surface topomorphy, surface roughness, chip geometry and cutting forces calculations that arising during the cutting process. A great number of simulations were performed in a milling machine centre, applying the discretized kinematics of the procedure and the final results were compared with measurements of Al7075-T651 experiments.

• Steel and Composite Structures
• /
• v.36 no.1
• /
• pp.87-101
• /
• 2020

A multi-scale epoxy/CNT/fiberglass annular sector plate is studied in this paper in the view of determining nonlinear forced vibration characteristics. A 3D Mori-Tanaka model is employed for evaluating multi-scale material properties. Thus, all of glass fibers are assumed to have uni-direction alignment and CNTs have random diffusion. The geometry of annular sector plate can be described based on the open angle and the value of inner/outer radius. In order to solve governing equations and derive exact forced vibration curves for the multi-scale annular sector, Jacobi elliptic functions are used. Obtained results demonstrate the significance of CNT distribution, geometric nonlinearity, applied force, fiberglass volume, open angle and fiber directions on forced vibration characteristics of multi-scale annular sector plates.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.37 no.5
• /
• pp.359-366
• /
• 2019

Indoor spatial data has great importance as the demand for representing the complex urban environment in the context of providing LBS (Location-based Services) is increasing. IndoorGML (Indoor Geographic Markup Language) has been established as the data standard for spatial data in providing indoor navigation, but its definitions and relationships must be expanded to increase its applications and to successfully delivering information to users. In this study, we propose an approach to integrate IndoorGML with Indoor POI (Points of Interest) data by extending the IndoorGML notion of space and topological relationships. We consider two cases of representing Indoor POI, by 3D geometry and by point primitive representation. Using the concepts of the NRS (node-relation structure) and multi-layered space representation of IndoorGML, we define layers to separate features that represent the spaces and the Indoor POI into separate, but related layers. The proposed methodology was implemented with real datasets to evaluate its effectiveness for performing indoor spatial analysis.

• Nuclear Engineering and Technology
• /
• v.51 no.4
• /
• pp.1075-1080
• /
• 2019

This paper presents a study on thermal neutron reflection properties of neutron guide for cylinder, spindle, elliptic and parabolic geometries using $^{241}Am-Be$ neutron source (5.2 Ci) and $BF_3$ detector, whereas neutron guide is important instrument for transportation of neutrons. To this goal, the required inner and outer radii of neutron guide have been calculated to achieve the highest guided thermal neutron flux based on MCNPX Monte Carlo code. The maximum flux of cylinder geometry with a length 50 cm has been obtained at an inner radius 9 cm and an outer radius 21 cm. Also, the maximum value of thermal neutron albedo is $0.46{\pm}0.001$ at 12 cm thickness of parabolic guide.

• Geomechanics and Engineering
• /
• v.24 no.6
• /
• pp.589-597
• /
• 2021

The present study evaluates geocell reinforced slope behavior. A three dimensional analysis is carried out to simulate soil and geocell elastoplastic behavior using the finite difference software FLAC3D. In order to investigate the geocell reinforcement effect, the geocell aperture size, thickness, geocell placement condition and soil compaction had been considered as variable parameters. Moreover, a comparison is evaluated between geocell reinforcing system and conventional planar reinforcement. The obtained results showed that the pocket size, thickness and soil compaction have considerable influence on the geocell reinforcement slope performance. Moreover, it was found that the critical sliding surface was bounded by the first geocell reinforcement and the slope stability increases, by increasing the vertical space between geocell layers. In addition, the comparison between geocell and geogrid reinforcement indicates the efficiency of using cellular honeycomb geosynthetic reinforcement.

• Journal of the Korean Society of Visualization
• /
• v.22 no.2
• /
• pp.90-95
• /
• 2024

This study examined changes in airway airflow characteristics before and after extensive surgery for tongue cancer, which includes neck dissection and reconstruction. Pre- and post-operative CBCT scans were used to model 3D upper airways. Computational fluid dynamics (CFD) simulations analyzed airflow and pressure variations. Results showed a significant reduction in airway volume post-surgery, especially in the posterior tongue and epiglottis areas, leading to increased airflow velocity and complex vortex formations. Pressure drop analysis revealed that post-surgery, higher negative pressure is required for inhalation, indicating increased breathing effort. This suggests that the surgical removal of cancerous tissues and lymph nodes, along with reconstruction, alters airway geometry significantly, potentially impacting respiratory function. The findings highlight the clinical importance of assessing airway changes in tongue cancer surgery to anticipate and mitigate postoperative respiratory complications.