• Korean Membrane Journal
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• v.1 no.1
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• pp.8-24
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• 1999

free volume in polymers is defined as the difference of the specific volume and the volume which is not available for the particular molecular motion which is responsible or the process that is considered . Relations between free volume and viscosity free volume and diffusion coefficient are pre-sented both in the case of simple low molecular weight liquids and in the case of polymers. Molecular models and free volume models are reminded starting from the equilibrium state equation of Simha and Somcynski. The non equilibrium situations of specific volume of glass polymers below Tg are shown introducing different relaxation volume equations which involve different material's parameters and con-cept of the fictitious temperature. The diffusivity equations of Vrentas and Duda are introduced both for the glassy and rubbery states. The possibility of introducing time relaxation functions is also suggested. The importance of finding experimental evidences of the free volume is stressed. highlights of the free volume measurement methods are given in particular as to dilatometry photocromy fluorescence electron spin resonance small angle X-ray scattering positron annihilation spectroscopy.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.43-50
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• 1993

Three-dimensional simulator for the ion implantation process is developed. The simulator based on an analytical model which would be a choice with high computational efficiency and accuracy. This is an important issue for the simulation of a numerous number of processing steps required in the fabrication of ULSI or GSI. The model can explain scattering and bulk channeling mechanism (1D). It can also explain depth dependent lateral diffusion effect(2D) and mask effect(3D). The model is consist of one-dimensional JPD(Joined Pearson Distribution) function and two-dimensional modified Gaussian functions. Final implanted profiles under typical mask structures such as hole, line and island structure are obtained with varying ion species.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.86-92
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• 2009

We fabricated the charged particle type display using opposite-charged two toner particles. The particles were composed of polymer, colorant($TiO_2$, carbon black) and external additives(nano-sized silica and so on). In fabrication process we controlled the putting layers of this toner particles on the inner panel. To get the effect of number of layers ($1{\sim}3$), we measured the threshold, driving and breakdown voltages, reflectivity, viewing angle, and color characteristics using RT-300 anisotropic scattering system. We ascertained that these voltages are increased with increasing of layers of particles. Cell gap between electrodes must be enlarged with increment of layers and the size of particles. The lumping phenomena of particles at near of the rib observed by optical system with same CIE values.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.370-373
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• 2009

X-ray lithography was employed to fabricate ITO-less high resolution sustain electrodes for plasma display panel (PDP). A polyimide film based X-ray mask and Xray sensitive Ag electrode paste were fabricated to check their effect on the patterning of Ag electrodes with less than 30 ${\mu}m$ in width. The X-ray lithographic method was found to be useful for the high resolution sustain electrode patterns due to the high penetration power and low scattering property of X-ray source.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.1
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• pp.15-22
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• 2011

Interconnect lines with inter-layer vias are experimentally characterized by using high-frequency S-parameter measurements. Test patterns are designed and fabricated using a package process. Then they are measured using Vector Network Analyzer (VNA) up to 25 GHz. Modeling a via as a circuit, its model parameters are determined. It is shown that the circuit model has excellent agreement with the measured S-parameters. The signal integrity of the lines with inter-layer vias is evaluated by using the developed circuit model. Thereby, it is shown that via may have a substantially deteriorative effect on the signal integrity of high-speed integrated circuits.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.3
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• pp.163-170
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• 2010

Both scatterer method and transfer matrix method are compared to analyze their characteristics, which are wave propagation models due to topographic change based on plane wave approximation. Results from the scatterer method are closer to the results obtained by the more accurate existing models and it is appraised that the scatterer method gives the clearer explanation about physical process involved in the wave transformation. Since both methods have analytical solutions, in the computational point of view they are very fast and easy to be implemented. Both methods give a good prediction for wave scattering by relatively simple bedform.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.6
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• pp.337-341
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• 2004

In this paper the effect of chaos induced instability in Brillouin-active fiber-ring sensor is described. The inherent optical feedback by the backscattered Stokes wave in optical fiber leads to instabilities in the form of optical chaos. The paradigm of optical chaos in fiber serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in communication and sensing. At weak power, the nature of the Brillouin instability can occur at before threshold. At strong power, the temporal evolution above threshold is periodic and at higher intensity can become chaotic. The threshold for the Brillouin instability in fiber-ring sensor is much lower than the threshold of the normal Brillouin instability process.

• Electrical & Electronic Materials
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• v.10 no.6
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• pp.581-588
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• 1997

The ionization energy and degree of ionization for Si and Ge with boron doping are calculated. The hole mobilities are then calculated as a function of doping concentration using the relaxation time approximation. When the screening effect is taken into account, the reduction of ionization energy results in the increase of degree of ionization. As a result, the calculated Si mobility becomes closer to the experimental data, whereas the calculated Ge mobility is almost independent of the screening effect. The inclusion of the broadening effect in the mobility calculation overestimates the ionized impurity scattering. As compared with the experiment, the screening effect is not avoidable to calculate Si and Ge mobilities, and the broadening effect must accompany with the hopping process.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.257-260
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• 2015

Light extinction characteristics of soot particles in ethylene and propane inverse diffusion flames have been experimentally investigated. The measured data suggested that the refractive index of soot particles varies with light wavelength due to PAH contents existing during the soot growth process. The results showed that the scattering effect is less important as the size of secondary particles rarely affects the optical properties of the soot even when the size is large enough to deviate from Rayleigh assumptions.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.2
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• pp.125-133
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• 1993

Electronic Speckle Pattern Interferometry(ESPI) using a CW laser, a video system and image processor was applied to the rotating displacement of rigid body. ESPI require no special surface preparation or attachments and displacements between any two arbitrary points on the surface can be measured. The characteristic speckle pattern formed when imaging a scattering surface illuminated by laser light retains phase information, which can be used for interferometric measurement of surface displacement. The application of this principle to measuring in-plane displacement resolved in one direction is described, together with the novel use of television equipment to detect and process the information contained in the speckle pattern. This is faster, and more convenient and versatile than customary photographic methods.