• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.18-18
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• 2003

Natural clays are composed of oxide layers whose thickness is about 1nm and cations existing between the layers. A number of these layers makes primary particles with a height of about 8∼10nm and these primary particles make aggregates with a size of about 0.1∼10$\mu\textrm{m}$. When layered silicate was made to be organophilic, by exchanging the interlayer cations with organic cationic molecules, the matrix polymer can penetrate between the layers to give a nanocomposite, where 1nm-scal clay layers exist separately in a continuous polymer matrix. These nanostructured hybrid organic-inorganic composites have attracted the great interest of researchers over the last 10 years. They exhibit improved performance properties compared with conventional composites, because their unique phase morphology by layer intercalation or exfoliation maximizes interfacial contact between the organic and inorganic phases and enhances interfacial properties. Since the advent of nylon-6/montmorillonite nanocomposite developed by Toyota Motor Co., the studies on layered silicate-polymer nanocomposites have been successfully extended to other polymer systems. They greatly improved the thermal, mechanical, barrier, and even the flame-retardant properties of the polymers.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.15 no.3
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• pp.105-111
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• 2009

In this work, source reduction of poly ethylene terephthalate (PET) packaging are discussed as aspect of sustainability, such as reuse, refill and recycling through the various treatment methods and historical studies for municipal solid waste (MSW) disposal. Since PET has good chemical, physical and mechanical properties, and provides good oxygen and carbon dioxide barrier properties, PET is one of the most widely used thermoplastic polyester in the U.S. and around the world. As the demand for non-renewable PET is increasing, several approaches have been developed to meet economical feasibility and environmental responsibility without degrading material performance. Several companies, such as Coca-Cola Co., Easterform Packaging Co. and Kraft, have tried to develop lightweight PET bottle, and some of lightweight PET bottles are already commercialized. Reuse and refilling for PET container is well developed in Europe, such as Denmark, German and Netherland by supportive legislation and policies. Recycling process is the best way to economically reduce PET waste. In consequence, advanced technique and further development must be provided due to increasing PET packaging waste.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.905-909
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• 2009

The new Junction Field Effect Transistors (JFETs) with Silicon-germanium (SiGe) layers is investigated. This structure uses SiGe layer to prevent out diffusion of boron in the channel region. In this paper, we report electrical properties of SiGe JFET measured under various design parameters influencing the performance of the device. Simulation results show that out diffusion of boron is reduced by the insertion SiGe layers. Because the SiGe layer acts as a barrier to prevent the spread of boron. This proposed JFET, regardless of changes in fabrication processes, accurate and stable cutoff voltage can be controlled. It is easy to maintain certain electrical characteristics to improve the yield of JFET devices.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.1
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• pp.14-19
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• 2003

The effect of the Pt electrode and the $Pt-IrO_2$ hybrid electrode on the performance of ferroelectric device was investigated. The modified Pt thin films with non-columnar structure significantly reduced the oxidation of TiN diffusion barrier layer, which rendered it possible to incorporate the simple stacked structure of Pt/TiN/poly-Si plug. When a $Pt-IrO_2$ hybrid electrode is applied, PZT thin film properties are influenced by the thickness and the partial coverage of the electrode layers. The optimized $Pt-IrO_2$ hybrid electrode significantly enhanced the fatigue properties of the PZT thin film with minimal leakage current.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1039-1042
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• 1995

In real time application such as motion control, it is hard to find the application of non-causal filtering due to its need for future position data, even though it shows wide usage in off-line digital signal processing. Recently, some of motion control areas such as learning and repetitive control use non-causal filtering technique in their application. these kinds of zero-lag non-causal filter application are very usful not only to reduce the machine vibration, but also to increase control accuracy with comparatively less work. In this paper, genuine method to implement zero-lag non-causal filter in a CNC is introduced. Also the variation of this implementation for the learning operation is suggested to give the NC better control performance for a specific job. By adopting the new NC architecture call Soft-NC, all these implementions are made possible here, and especially large memory requirement which hinders their usage for many years is no longer barrier in their real world application.

• Journal of the Korean Society for Heat Treatment
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• v.15 no.3
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• pp.113-117
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• 2002

Fatigue characteristics of ferroelectric $Pb(Zr,Ti)O_3$ (PZT) based capacitors through donor doping is reported in this paper. La substitution up to 10% were carried out to study systematically the fatigue behaviors of epitaxial ferroelectric capacitors grown on Si using $(Ti_{0.9}Al_{0.1})N/Pt$ conducting barrier composite. Ferroelectric capacitors substituted with 10% La show sufficient low voltage switched polarization and fatigue free performance. Systematic decrease in the tetragonality of the ferroelectric phase (i.e., c/a ratio) results in the corresponding reduction in coercive voltage, sufficient remnant polarization at 1.5-3V, and good fatigue property.

• Journal of the Korean Professional Engineers Association
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• v.14 no.4
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• pp.15-25
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• 1981

Electrical behaviors of the divalent silver oxide-zinc cell were analyzed for imporving capacity and keeping electrodes from passivation or sharp increases of cell internal resistance in the course of discharge. One of primary factors in relation to lowering performance can be depicted by cell internal resistance increase being created by various routes, first by insufficiency and/or the carbonation of the electrolyte, secondly by barrier blockage, thirdly by electrode passivation which are due to improper material use of wrong processing, and by gassing as fourth cause. The carbonation causes electrobyte to have impedance up as well as poor amalgamation, resulting in vigorous corrosion reaction of copper plated inner top, evolving hydrogen gas. Electrical characteristics of the cell was reviewed to elucidate relationships between the discharge capacity and the cell internal resistance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.151-154
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• 1998

We have investigated a correlation of the electrical properties of the Pd/Ge/Pd/Ti/Au ohmic contact on n-InGaAs with its microstructures for the high temperature application of compound semiconductor devices. The samples were heat-treated by the rapid thermal annealing at various temperatures. In the contact system, moderately good specific contact resistance was obtained even before annealing because of the low metals-InGaAs barrier height, and better ohmic performances were observed by annealing up to 400˚C. But the ohmic performance was degraded after annealing at 450˚C due to the increment of Pd$_2$Ga$\sub$5/ phases.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.265-270
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• 1996

The temperature distribution in the pellet was obtained from beginning the general heat conduction equation. The thermal conductivity of pellet used the SIMFUEL data that made clear the effect of burnup on the thermal conductivity degradation. Since the pellet rim acts as the thermal barrier to heat flow. the pellet was subdivided into several rings in which the outer ring was adjusted to play almost the same role as the rim. The local burup in each ring except the outer ring was calculated from the power depression factor based on FASER results. whereas the rim burnup at the outer ring was achieved by the pellet averaged burnup based on the empirical relation. The rim changed to the equivalent Xe film so the predicted temperature shooed the thermal jump across the rim. The observed temperature profiles depended on linear heat generation rate. fuel burnup. and power depression factor. The thermal conductivity degradation modelling can be applied to the fuel performance code to high burnup fuel,

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.66-69
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• 2001

A subsurface containment system which is constructed by pumping a gelling liquid (Colloidal Silica) into the unsaturated medium is investigated by developing a mathematical model and conducting numerical simulations. The proposed model is verified by comparing experimentally and numerically determined hydraulic conductivities of gel-treated soil columns at different Colloidal Silica (CS) injection volumes. The numerical experiments indicate that an impermeable gel layer is formed within the time period twice the gel-point. At the Same normalized time, the CS solutions with lower NaCl concentrations result ill further migration and poor Performance in plugging the pore space.