• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.161-162
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• 2002

This study concerns the tribological behaviors of ultra-thin DLC coating with 3 nm thickness deposited in a mixed gas of argon + 20 % hydrogen as a function of humidity. Reciprocating wear tests employing a micro wear tester were performed under various normal loads and relative humidity in air environment. The chemical composition of the original and worn surfaces were studied by Auger electron spectroscopy (AES). It showed that the ultra-thin DLC coating exhibited low friction with enough wear stability at low normal load (0.18 N) and its tribological behavior was strongly dependent on the humidity. The sample surfaces before and after the test were examined using atomic force microscopy (AFM). Capillary force and meniscus areas were discussed in order to explain the influence of humidity on the friction force.

• Journal of the Korean Applied Science and Technology
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• v.23 no.3
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• pp.238-242
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• 2006

Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electric conduction mechanism of PI Ultra-Thin Films was investigated at room temperature. At low electric field, ohmic conduction $(I{\propto}V)$ was observed and the calculated electrical conductivity was about $4.23{\times}10^{-15}{\sim}9.81{\times}10^{-15}\;S/cm$. At high electric field, nonohmic conduction $(I{\propto}V^2)$ was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of PI Ultra-Thin Films was about 7.0.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.121-124
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• 1990

In this paper, we study the electrical conduction mechanism in Langmuir-Blodgett(LB) ultra thin films. The LB device was a metal/LB films/metal sandwich structure, where metal is electrode. In our experiments, the temperature depend on the current at above $0^{\circ}C$. This phenomena show that the electrical conduction current is a schottky current inherent to LB ultra thin films.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.179-184
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• 2010

The present study is focused on the deep drawability and product qualities of ultra thin beryllium copper sheet metal. The goal of this research is to investigate the limit drawing ratio in deep drawing of ultra thin beryllium copper metal. For the experiment, beryllium copper(C1720, $50{\mu}m$ in thickness) is used. Tensile test are also carried out to find out the material properties. Deep drawing experiments are carried out in Universal Testing Machine(UTM) to obtain limit drawing ratio. Deep drawing tests are carried out for various specimen sizes. Teflon film is used as a lubricant and constant blank holding force is imposed. Sheet thickness and surface hardness are measured along radial direction after deep drawing. Thickness is measured using optical microscope. For beryllium copper(C1720), the maximum LDR of 2.4 is obtained when the die shoulder radius is 20 or 30 times of sheet thickness.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.175-178
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• 1988

A film is fabricated by depositing several sliced organic ultra thin films on a slide glass. Both UV-absorbance and the capacitance of a multi - layered organic ultra thin film with (N-docosyl pyridinium)-TCNQ(1:2) complex have a desired value on the condition of well alignment in depositing several layers. Forethermore the conductivity of this film measured by the direction of either horizontal or vertical axis. respectively, is results in a quite different value.

• Macromolecular Research
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• v.10 no.5
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• pp.273-277
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• 2002

Ultra-thin polymer films containing cobalt(II) meso-tetraphenylporphyrin(CoTPP) have been prepared by vacuum codeposition of the metal complex and trans-2-butene as an organic monomer using an inductively coupled RF glow discharge operating at 7-9 Watts. The polymer films were characterized by sorption measurements. Sorption data obtained for polymer films containing CoTPP indicate that the CoTPP molecules are capable of reversibly binding oxygen molecules. It was found that the adjacent CoTPP molecules in the aggregated metal complex phase could irreversibly share the oxygen molecules. A dispersion of the metal complex molecules in the polymer matrix was made to maintain the reversible reactivity of the metal complex molecules with oxygen in the polymer films via vacuum evaporation process. The Henry mode solubility constant, the Langmuir mode capacity constant, the amount of binding oxygen, and the dissociation equilibrium in the dual mode sorption theory were discussed.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.131-136
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• 1995

Ultra-thin films of hexyltriphenylphosphonium-TCNQ(1:1) complex were formed on various substrates by Langmuir-Blodgett technique, where hexyltriphenylphosphonium-TCNQ(1:1) complex was synthesized by attaching hexyltriphenylphosphonium group to TCNQ. The reaction product was identified with FT-IR, and UV-Vis absorption spectroscopies. The formation of ultra-thin films of hexyltriphenylphosphonium-TCNQ(1:1) complex was confirmed also by FT-IR, and UV/Vis absorption spectroscopies.

• Transactions of Materials Processing
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• v.26 no.3
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• pp.144-149
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• 2017

In order to characterize the macroscopic mechanical response of ultra-thin (0.1 mm thick) ferritic stainless steel sheet at various loading paths, a crystal plasticity finite element method (CP-FEM) was introduced. The accuracy of the prediction results was validated by comparing with the experimental data. Based on the results, the forming limit diagram (FLD) was predicted using a modified Marchinicak-Kuczinski model coupled to a non-quadratic anisotropic yield function, namely, Yld2000-2d. The predicted FLD was found to be in good agreement with the experimental data.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.343-346
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• 2015

Ultra-thin body transistor is one of the emerging devices since it control leakage current flows through substrate. In addition, it can be operated by double gates, thus, its on/off current ratio is higher than conventional counterpart. In this paper, we design and investigate a CMOS inverter based on ultra-thin body MOSFETs to estimate its performance in real application. NEGF (non-equilibrium Green's function) method is used to obatain relationship between drain current and voltage. DC transfer is extracted from the relationship, and FO4 (fanout-of-4) propagation delay is reported as 5.1 ps estimated by a simple model.

• Steel and Composite Structures
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• v.12 no.2
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• pp.167-181
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• 2012

Ultra high performance cementitious composite material is applied to the design of multifunctional permanent form for bridge pier in this paper. The basic properties and calculating constitutive model of ultra high performance cementitious composite are introduced briefly. According to momental theory of thin-walled shell, the analytical solutions of structural behavior parameters including circumferential stress, longitudinal stress and shear stress are derived for UHPCC thin-walled circular tube. Based on relevant code of construction loads (MHURD of PPC 2008), the calculating parameter expression of construction loads for UHPCC thin-walled circular tube is presented. With geometrical dimensions of typical pier, the structural behavior parameters of UHPCC tube under construction loads are calculated. The effects of geometrical parameters of UHPCC tube on structural behavior are analyzed and the design advices for UHPCC tube are proposed. This paper shall provide a scientific reference for UHPCC permanent form design and UHPCC hybrid structure application.