• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.3
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• pp.185-192
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• 2004

Vibration table is required to obtain high packing density in expendable pattern casting process. Packing density. which is an important manufacture factor, depends on the vibration pattern induced by vibration table. In general, circular vibration pattern is recognized as the best pattern. The existing vibration table is investigated to identify current vibration pattern and consider a countermeasure. Modal test is utilized to identify the dynamic characteristics of vibration table, and finite element method is used to propose the improved design. In simulation using finite element method, the position of stiffeners is obtained to satisfy the required dynamic characteristics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.160-165
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• 2002

Vibration table is required to obtain high packing density in expendable pattern casting process. Packing density, which is an important manufacture factor, depends on the vibration pattern induced by vibration table. In general, circular vibration pattern is recognized as the best pattern. The existing vibration table is investigated to identify current vibration pattern and consider a countermeasure. Modal test is utilized to identify the dynamic characteristics of vibration table, and finite element method is used to present the improved design.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.76-81
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• 2006

In this study, warpage characteristics of mobile phone cover through injection molding process were investigated using design of experiments in injection molding process. Warpage in plastic injection molding has a significant effect on quality of product. Effects of injection time, packing pressure, packing time, mold temperature and melt temperature on the warpage of mobile phone cover were considered by numerical analysis and experiment with Taguchi method. The degree of warpage for the injection molded part was measured by using three dimensional coordinate measurement machine. It was shown that temperature control factor has more significant effect on the warpage of mobile phone cover than pressure control factor.

• Transactions of Materials Processing
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• v.15 no.9 s.90
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• pp.641-647
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• 2006

During the injection molding process an excessive packing can occur in the smaller volume cavity because of volumetric difference of the family-mold. It causes warpage by increased residual stress in the product and flesh by over packing. In this study, we used a variable-runner system for the filling balance of the cavities by changing the cross-sectional area of a runner, and confirmed the filling imbalance by temperature and pressure sensors. We carried out experiments to examine the influence of types of resins such as LDPE/ABS/PA6,6 on the filling balancing of the system, in order to help mold designers, who can easily adopt the variable-runner system to their design. We also examined filling imbalance in the system with CAE analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.322.2-322
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• 2002

Vibration table is required to obtain high packing density in lost form casting process. Packing density, which is important manufacture factor, depends on the vibration pattern induced by vibration table. In general, circular vibration pattern is recognized as the best pattern. The existing vibration table is investigated to identify current vibration pattern and consider a countermeasure. Modal test is utilized to identify the dynamic characteristics of vibration table, and finite element method is used to present the improved design

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.71-78
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• 1999

The application range of injection molded parts is expanding by the development of engineering plastics with good mechanical properties. Plastic gears are specially used as automotive parts due to an excellent performance in the characteristics of a strength vs. weight, and the study of injection molding process of plastic gear using Nylon66 is performed in this study. Filling, packing and cooling analyses were done by using the simulation software like Moldflow, and a mold was designed by following the simulation results. Pin-point gates with three points were taken to satisfy the design guides like a full-shot, and lower clamping force and uniform shrinkage. Characteristics of shrinkage of molded gear and temperature difference between cavity and core sides of a mold were shown.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.269-274
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• 2003

Vibration table is required to obtain high packing density in expendable pattern casting process. Packing density, which is an important manufacture factor, depends on the vibration pattern induced by vibration table. Modal test is utilized to identify the dynamic characteristics of vibration table. And finite element method is used to modify flask by fixing the stiffener. The positions of stiffener to modify are found and the natural frequency could be easily shifted to the objective value by using sensitivity analysis.

• Journal of Korea Foundry Society
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• v.31 no.4
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• pp.186-190
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• 2011

A new Cu-Hf-Al-Be monolithic bulk amorphous alloy was developed utilizing minimal use of toxic and expensive Be. The developed alloy exhibits a large glass forming ability (GFA) (${\Phi}8$ mm). The possible mechanisms underlying the enhancement of the glass forming ability by this alloy are discussed based on the dimensionless parameter ${\gamma}$. In addition, alloy design strategy for the improvement of GFA is proposed in the viewpoint of heat of mixing (${\Delta}H_{mix}$)difference and atomic packing state.

• Computers and Concrete
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• v.6 no.2
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• pp.133-153
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• 2009

Discrete element modeling (DEM) in concrete technology is concerned with design and use of models that constitute a schematization of reality with operational potentials. This paper discusses the material science principles governing the design of DEM systems and evaluates the consequences for their operational potentials. It surveys the two families in physical discrete element modeling in concrete technology, only touching upon probabilistic DEM concepts as alternatives. Many common DEM systems are based on random sequential addition (RSA) procedures; their operational potentials are limited to low configuration-sensitivity features of material structure, underlying material performance characteristics of low structure-sensitivity. The second family of DEM systems employs concurrent algorithms, involving particle interaction mechanisms. Static and dynamic solutions are realized to solve particle overlap. This second family offers a far more realistic schematization of reality as to particle configuration. The operational potentials of this family involve valid approaches to structure-sensitive mechanical or durability properties. Illustrative 2D examples of fresh cement particle packing and pore formation during maturation are elaborated to demonstrate this. Mainstream fields of present day and expected application of DEM are sketched. Violation of the scientific knowledge of to day underlying these operational potentials will give rise to unreliable solutions.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.12
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• pp.31-39
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• 1998

This paper presents the design and implementation of a new multimedia fixed-point DSP (MDSP) core for portable multimedia applications. The MDSP instruction set is designed through the analysis of multimedia algorithms and DSP instruction sets. The MDSP architecture employs parallel processing techniques, such as SIMD and vector processing as well as DSP techniques. The instruction set can handle various data formats and MDSP can perform two MAC operations in parallel. The switching network and packing network can increase the performance by overlapping data rearrangement cycles with computation cycles. We have designed Verilog HDL models and the 0.6 $\mu\textrm{m}$ Samsung KG75000 SOG library is used. The total gate count is 68,831 and the clock frequency is 30 MHz.