• ETRI Journal
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• v.27 no.5
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• pp.628-634
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• 2005

From AC analysis results utilizing a 2-dimensional device simulator, we extracted an AC-equivalent circuit of a grounded-gate NMOS (ggNMOS) electrostatic discharge (ESD) protection device. The extracted equivalent circuit is utilized to analyze the effects of the parasitics in a ggNMOS protection device on the characteristics of a low noise amplifier (LNA). We have shown that the effects of the parasitics can appear exaggerated for an impedance matching aspect and that the noise contribution of the parasitic resistances cannot be counted if the ggNMOS protection device is modeled by a single capacitor, as in prior publications. We have confirmed that the major changes in the characteristics of an LNA when connecting an NMOS protection device at the input are reduction of the power gain and degradation of the noise performance. We have also shown that the performance degradation worsens as the substrate resistance is reduced, which could not be detected if a single capacitor model is used.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.34-41
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• 2006

Microlens arrays were fabricated by a modified LIGA process composed of the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, both hot embossing and microinjection molding processes have been successfully utilized with the fabricated mold insert. Replicated microlenses showed very good surface roughness with the order of 1 nm. The focal lengths of the injection molded microlenses were successfully estimated theoretically and also measured experimentally.

• Clean Technology
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• v.22 no.1
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• pp.45-52
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• 2016

This study reports on the modeling and simulation of heat transfer in packaging boxes used for vaccine shipping. Both water and n-tetradecane are used as primary insulation materials inside a multi-slab system. The one-dimensional model, which is a spherical model using a radius equivalent to the rectangular geometry of container, is applied in this study. N-tetradecane with low thermal diffusivity and proper phase transition temperature exhibits higher heat transfer resistance during both heating and cooling processes compared to water. Thus, n-tetradecane is a better candidate as an insulating material for packaging containers for vaccine shipping. Furthermore, the developed method can also become a rapid and economic tool for screening appropriate phase change materials used as insulation materials with suitable properties in logistics applications.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.21-38
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• 2009

The use of multi scale modeling concepts and simulation techniques to study the destabilization of an ultrathin layer of oxide interface between a metal substrate and the surrounding environment is considered. Of particular interest are chemo-mechanical behavior of this interface in the context of a molecular-level description of stress corrosion cracking. Motivated by our previous molecular dynamics simulations of unit processes in materials strength and toughness, we examine the challenges of dealing with chemical reactivity on an equal footing with mechanical deformation, (a) understanding electron transfer processes using first-principles methods, (b) modeling cation transport and associated charged defect migration kinetics, and (c) simulation of pit nucleation and intergranular deformation to initiate the breakdown of the oxide interlayer. These problems illustrate a level of multi-scale complexity that would be practically impossible to attack by other means; they also point to a perspective framework that could guide future research in the broad computational science community.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.37-38
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• 2012

In this research, the application of PUF modeling which is configured to be doped oxide material on Si substrate and this oxide material is to prevent corrosion of the security chip device. It is to design device replication technology through applying the electromagnetic formulation and its analysis of a device and find ways to PUF design.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.502-505
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• 2005

The modeling for the cell gap process characteristic on the flexible liquid crystal display (LCD) process was investigated by response surface methodology (RSM). D-optimal design is carried out to build the design matrix. The analysis of variance (ANOVA) technique was used to analyze the significance level. The statistical analysis was used to verify the response surface model. The desirability function was used in the design-space optimization.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1301-1303
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• 1997

This study was performed to investigate the deposition mechanism of $SiO_2$ by ArF excimer Laser(193nm) CVD with $Si_2H_6$ and $N_2O$ gas mixture and evaluate Laser CVD quantitatively by modeling. In this study, new model of $SiO_2$ deposition process by Laser CVD is introduced and deposition rates are simulated by computer with the basis on this modeling. And simulation results are compared with experimental results measured at various conditions such as reaction gas ratio, chamber pressure, substrate temperature and laser beam intensity.

• Smart Structures and Systems
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• v.7 no.3
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• pp.199-211
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• 2011

Using computational modeling, we design a pair of biomimetic microcapsules that exploit chemical mechanisms to communicate and alter their local environment. As a result, these synthetic objects can undergo autonomous, directed motion. In the simulations, signaling microcapsules release "agonist" particles, while target microcapsules release "antagonist" particles and the permeabilities of both capsule types depend on the local particle concentration in the surrounding solution. Additionally, the released nanoscopic particles can bind to the underlying substrate and thereby create adhesion gradients that propel the microcapsules to move. Hydrodynamic interactions and the feedback mechanism provided by the dissolved particles are both necessary to achieve the cooperative behavior exhibited by these microcapsules. Our model provides a platform for integrating both the spatial and temporal behavior of assemblies of "artificial cells", and allows us to design a rich variety of structures capable of exhibiting complex dynamics. Due to the cell-like attributes of polymeric microcapsules and polymersomes, material systems are available for realizing our predictions.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.1003-1010
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• 2002

Caspase 3, a member of cysteine protease family, is well known as a major apoptosis effector and is involved in cell death as a result of ischemic diseases such as stroke and myocardial infarction, therefore the inhibition of caspase 3 may protect those apoptotic cell damages. During the high-throughput screening of the compounds from the Korea Chemical Bank, berberine derivatives (A and B), an isoquinoline alkaloid, have been identified as potential inhibitors for caspase 3. Based on this finding we carried out molecular modeling study to identify the pharmacophoric elements of berberine structure which interact with a substrate-recognition binding site of caspase 3 and came up with several novel scaffolds. In this report, we will discuss the molecular modeling, syntheses and the enzyme inhibitory activities of these novel compounds.

• Advances in materials Research
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• v.1 no.1
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• pp.37-49
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• 2012

In this paper, we present modeling and characterization of CNT-based TSVs to be used in high-frequency RF applications. We have developed an integrated model of CNT-based TSVs by incorporating the quantum confinement effects of CNTs with the kinetic inductance phenomenon at high frequencies. Substrate parasitics have been appropriately modeled as a monolithic microwave capacitor with the resonant line technique using a two-polynomial equation. Different parametric variations in the model have been outlined as case studies. Furthermore, electrical performance and signal integrity analysis on different cases have been used to determine the optimized configuration for CNT-based TSVs for high frequency RF applications.