• Elastomers and Composites
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• v.58 no.1
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• pp.11-16
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• 2023

Electronic skin (e-skin), devices that are mounted on or attached to human skin, have advanced in recent times. Yet, the development of a power supply for e-skin remains a challenge. A stretchable thermoelectric generator is a promising power supply for the e-skin patches. It is a safe and semi-permanent energy harvesting device that uses body heat for generating power. Carbon nanotube (CNT) clays are used in energy-harvesting e-skin patches. In this study, we report improved thermoelectric performance of CNT clays by using chemical doping and physical blending of thermoelectric enhancers. The n-type and p-type thermoelectric enhancers increase electrical conductivity, leading to increased power factors of the thermoelectric CNT clays. The blend of CNT clays and enhancers is intrinsically stretchable up to 50% while maintaining its thermoelectric property.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.419-420
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• 2008

In this study, high quality (Al,N)-codoped p-type ZnO thin films were obtained by DC magnetron sputtering. The film on buffer layer grown in 80% $N_2$ ambient shows highest hole concentration of $2.93\times10^{17}cm^{-3}$. The films show hole concentration in the range of $1.5\times10^{15}$ to $2.93\times10^{17}cm^{-3}$, resistivity of 131.2 to 2.864 $\Omega$cm, mobility of 3.99 to 31.6 $cm^2V^{-1}s^{-1}$. The films on Si show easier p-doping in ZnO than those on buffer layer. The film on Si shows the highest quality of optical photoluminescence (PL) characteristics. The donor energy level $(E_d)$ of (Al,N)-codoped ZnO films is about 50 meV and acceptor energy level $(E_a)$ is in the range of 63 to 71 meV. It will help to improve p-type ZnO films.

• Bulletin of the Korean Mathematical Society
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• v.22 no.1
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• pp.7-10
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• 1985

For each a.mem.S and f.mem.m(S), denote by $l_{a}$ f(s)=f(as) for all s.mem.S. If A is a norm closed left translation invariant subalgebra of m(S) (i.e. $l_{a}$ f.mem.A whenever f.mem.A and a.mem.S) containing 1, the constant ont function on S and .phi..mem. $A^{*}$, the dual of A, then .phi. is a mean on A if .phi.(f).geq.0 for f.geq.0 and .phi.(1) = 1, .phi. is multiplicative if .phi. (fg)=.phi.(f).phi.(g) for all f, g.mem.A; .phi. is left invariant if .phi.(1sf)=.phi.(f) for all s.mem.S and f.mem.A. It is well known that the set of multiplicative means on m(S) is precisely .betha.S, the Stone-Cech compactification of S[7]. A subalgebra of m(S) is (extremely) left amenable, denoted by (ELA)LA if it is nom closed, left translation invariant containing contants and has a multiplicative left invariant mean (LIM). A semigroup S is (ELA) LA, if m(S) is (ELA)LA. A subset E.contnd.S is left thick (T. Mitchell, [4]) if for any finite subser F.contnd.S, there exists s.mem.S such that $F_{s}$ .contnd.E or equivalently, the family { $s^{-1}$ E : s.mem.S} has finite intersection property.y.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.224-228
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• 2014

The electrocaloric effect of 9/65/35 PLZT thin film fabricated by the sol-gel method, which has not been studied yet, was investigated for its structural, electrical properties as well as temperature change property. The relaxor ferroelectric property of 9/65/35 PLZT thin film was confirmed by examining its dielectric and electrical properties. The relaxor property can cause a more pronounced electrocaloric effect (ECE) in a wider temperature range than normal ferroelectric film. To avoid errors caused by using an indirect measurement method, the leakage current generated by increasing temperatures was minimized by using the optimal maximum electric field ($350kVcm^{-1}$) in the thin film. The largest temperature change ${\delta}T$ (0.23 K) and the electrocaloric strength ${\xi}$ (0.68 mkcm/kV), calculated by equations were obtained. The maximum field change ${\delta}E$ ($191kVcm^{-1}$) was in the vicinity of the curie temperature ($200^{\circ}C$).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.441-445
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• 2005

In the resent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. But, no detailed researches between the thermo-dynamic property in Nitinol alloy have been done yet. In this study, the thermal property of high temperature Nitinol shape memory alloy were evaluated using differential scanning calorimeter(DSC). The structure property was investigated using X-ray diffraction(XRD). A dynamic mechanical analyzer(DMA) with three point bending mode was used to study storage and loss modulus of shape memory alloy according to the thirteen frequencies in the temperature range between 30 and $200^{\circ}C$. The effects of the temperature heating/cooling rate, the frequency on the damping capacity have been systematically investigated. Such a frequency and temperature changes also influenced significantly to the damping behavior of the shape memory alloy. It was also found that Nitinol exhibited high damping capacity during phase transformation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.989-995
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• 2000

G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$ is a very promising material for the high-speed device due to the fact that electron and hole mobilities for the strained G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$ are greatly enhanced. Because G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$ has a direct band gap for the proper combination of x and y, it can be applied to the optoelectronic device. Therefore, the study of the electrical property for G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$(001) with a direct energy gap is needed. G $e_{1-x}$ S $n_{x}$ layer can not be grown thickly due to the large difference of lattice constants. This fact prefers the structure of the device where electrons and holes move in the plane direction. The transverse mobilities of electron and hole for G $e_{0.8}$S $n_{0.2}$Ge(001) are 2~3 times larger than those for Ge/Ge/ sub0.8/S $n_{0.2}$(001). Therefore, G $e_{0.8}$S $n_{0.2}$Ge(001) is expected to be better than Ge/G $e_{0.8}$S $n_{0.2}$(001) for the development of the high-speed device.h-speed device.device.h-speed device. device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.413-417
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• 2002

E-mail was very particular way of communication in the past, but it becomes one of daily communication methods now. Due to E-mail has a property which is not complete for security, sometimes it is used for purpose of commercial or badthings, therefore it becomes the latest problem to keep off a Spam-mail and commercial advertising E-mail, many ways to keep off were perposed for it. In this paper, I explained how to sort and keep off these Spam-mail and commercial advertising E-mail with three way, prevention by server level, prevention by construction of network level, prevention by client level. we designed a prevention system for Spam-mail and implemented it by Visual Basic.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.277-284
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• 1999

This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.326-328
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• 1999

We investigated the effects of residual gas partial pressure on the property of a CeO$_2$ buffer layer on a textured Ni tape, where the buffer layer was deposited by e-beam evaporation. The oxygen partial pressure were varied from 10$^{-7}$ to 10$^{-4}$ Torr. we also changed the surface condition for the surface oxygenation. We'll describe the detail of the resultant textures of the buffer layers and effects of YBCO growth on them

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.252-259
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• 1999

One of the most important factors for a proper design of a slender compression member may be the exact determination of the elastic critical load of that member. In the cases of non-prismatic compression member, however, there are times when the exact critical load becomes impossible to determinate if one relies on the neutral equilibrium method or energy principle. Here in this paper, the approximate critical loads of symmetrically or non-symmetrically tapered members are computed by finite element method. The two parameters considered in this numerical analysis are the taper parameter, $\alpha$ and the sectional property parameters, m. The computed results for each sectional property parameter, m are presented in an algebraic equation which agrees with those by F.E.M The algebraic equation can be easily used by structural engineers, who are engaged in structural analysis and design of non-prismatic compression member.