• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.354-357
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• 2008

In this study, the casting process using forged insert was applied to manufacturing a knuckle, in order to prove that application of casting process using forged insert is likely to get the effect of light weight and superior mechanical characteristic compared with existing casting products. Firstly, in the forging experiment, it was confirmed that the optimal configuration of the forged insert could be predicted by FE analysis. And by using FVM (Finite Volume Method) software, it was verified that a proposed casting design was available. To identify the mechanical characteristic of the final casting product, the microstructual observation and hardness test were performed at the boundary zone between forging and casting part.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.607-608
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• 2008

Locking time of the DLL is the important design issue in case of clock gating for low power system. For precise analysis of the locking speed of the DLL, this paper analyzes the locking process of the DLL in time domain. Analysis result shows that the value of the DLL bandwidth over reference frequency should be limited to below 1 ($i.e.w_n/F_{REF}<1$) for the stable operation and relation between bandwidth and lock time is expressed by log function.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.33-39
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• 2014

In this paper, a new on-chip aging sensing circuit based on flip-flops is proposed to detect a circuit failure of MOSFET digital circuits casued by aging phenomenon such as HCI and BTI. The proposed circuit uses timing windows to warn against a guardband violation of sequential circuits, and generates three warning bits right before circuit failures occur. The generated bits can apply to an adaptive self-tuning method for reliable system design as control signals. The aging sensor circuit has been implemented using 0.11um CMOS technology and evaluated by $4{\times}4$ multiplier with power gating structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5737-5742
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• 2015

Insert injection molding is a process in which molten plastic is injected into a mold that contains a pre-placed insert. During the injection stage, the insert can be deformed by the pressure applied by the polymer melts. The deformation of the insert changes the width of the flow path around the insert, which can cause several defects such as short shots or warpages of the parts. In order to reduce the deformation of the insert, it is important to achieve successful design of gating system, insert geometry, and molding conditions. In the present study, the insert deformations that occured during the injection molding of the BLDC motor stator were investigated by numerical analyses. The gate location and the insert shape were modified to reduce the insert deformation. Finally, the injection molding with the modified designs was carried out, and it was confirmed that the insert deformation was reduced.

• Molecules and Cells
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• v.27 no.5
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• pp.591-599
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• 2009

Nicotinic acetylcholine receptors (nAChRs) play important roles in nervous system functions and are involved in a variety of diseases. We previously demonstrated that ginsenosides, the active ingredients of Panax ginseng, inhibit subsets of nAChR channel currents, but not ${\alpha}7$, expressed in Xenopus laevis oocytes. Mutation of the highly conserved Leu247 to Thr247 in the transmembrane domain 2 (TM2) channel pore region of ${\alpha}7$ nAChR induces alterations in channel gating properties and converts ${\alpha}7$ nAChR antagonists into agonists. In the present study, we assessed how point mutations in the Leu247 residue leading to various amino acids affect 20(S)-ginsenoside $Rg_3$ ($Rg_3$) activity against the ${\alpha}7$ nAChR. Mutation of L247 to L247A, L247D, L247E, L247I, L247S, and L247T, but not L247K, rendered mutant receptors sensitive to $Rg_3$. We further characterized $Rg_3$ regulation of L247T receptors. We found that $Rg_3$ inhibition of mutant ${\alpha}7$ nAChR channel currents was reversible and concentration-dependent. $Rg_3$ inhibition was strongly voltage-dependent and noncompetitive manner. These results indicate that the interaction between $Rg_3$ and mutant receptors might differ from its interaction with the wild-type receptor. To identify differences in $Rg_3$ interactions between wild-type and L247T receptors, we utilized docked modeling. This modeling revealed that $Rg_3$ forms hydrogen bonds with amino acids, such as Ser240 of subunit I and Thr244 of subunit II and V at the channel pore, whereas $Rg_3$ localizes at the interface of the two wild-type receptor subunits. These results indicate that mutation of Leu247 to Thr247 induces conformational changes in the wild-type receptor and provides a binding pocket for $Rg_3$ at the channel pore.