• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.46-50
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• 1996

In this paper, xPb(Zn$\_$1/3/Nb$\_$2/3/)O$_3$-yPbTiO$_3$-zPbZrO$_3$-zPbZrO$_3$ (0.5wt%)MnO$_2$ ceramics were fabricated by the mixed oxide method sintered at 1250$^{\circ}C$ for 2[hrs] and then the dielectric and pyroelectric properties were investigated. In 0.10PZN-0.45PT-0.47PZ sample, dielectric constant was 829 and in the case of 01.5PZN-0.45PT-0.40PZ sample, pyroelectric current and pyroelectric coefficient were 0.95 x 10$\^$-7/ [A] and 7.6 x 10$\^$-1/ [C/$\textrm{cm}^2$$.$$^{\circ}C$]. Figure of merits of pyroelectric current and voltage and detectivity, in same sample, has shown good properties, that were 2.4 x 10$\^$-8/[C$.$cm/J], 5.5 x 10$\^$-11/[C$.$cm/J], 1.6 x 10$\^$-8/ [C$.$cm/J].

• Ceramist
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• v.22 no.1
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• pp.36-55
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• 2019

Atomically thin two-dimensional (2D) nanomaterials, including transition metal dichalcogenides (TMDs), graphene, boron nitride, and black phosphorus, have opened up new opportunities for the next generation optoelectronics owing to their unique properties such as high absorbance coefficient, high carrier mobility, tunable band gap, strong light-matter interaction, and flexibility. In this review, photodetectors based on 2D nanomaterials are classified with respect to critical element technology (e.g., active channel, contact, interface, and passivation). We discuss key ideas for improving the performance of the 2D photodetectors. In addition, figure-of-merits (responsivity, detectivity, response speed, and wavelength spectrum range) are compared to evaluate the performance of diverse 2D photodetectors. In order to achieve highly reliable 2D photodetectors, in-depth studies on material synthesis, device structure, and integration process are still essential. We hope that this review article is able to render the inspiration for the breakthrough of the 2D photodetector research field.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.543-549
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• 2003

In order to investigate the thermoelectric properties of $Zn_{k}$ $In_2$$O_{ 3＋k}$ homologous compounds, the samples of $Zn_{k}$ /$In_2$$O_{3＋k}$ / (k = integer between 1 and 9) were prepared by calcining the mixed powders of ZnO and $In_2$$O_3$fellowed by sintering at 1823 K for 2 hours in air, and their electrical conductivities and Seebeck coefficients were measured as a function of temperature in the range of 500 K to 1150 K. X-ray diffraction analysis of the sintered samples clarified that single-phase specimens were obtained for $Zn_{k} /$In_2$$O_{3＋k}$ with k = 3, 4, 5, 7, 8, 9. Electrical conductivity of the $Zn_{k}$ $In_2$$O_{3＋k}$ / decreased with increasing temperature, and decreased with increasing k for k $\geq$ 3. The Seebeck coefficient was negative at all the temperatures for all compositions, confirming that $Zn_{k}$ $In_2$$O_{3＋k}$ / is an n-type semiconductor. Absolute values of the Seebeck coefficient increased linearly with increasing temperature and increased with increasing k for k $\geq$ 3. The temperature dependence of the Seebeck coefficient indicated that Z $n_{k}$I $n_2$ $O_{3＋k}$ could be treated as an extrinsic degenerate semiconductor. Figure-of-merits of Z $n_{k}$I $n_2$ $O_{3＋k}$ were evaluated from the measured electrical conductivity and Seebeck coefficient, and the reported thermal conductivity. Z $n_{7}$ I $n_2$ $O_{10}$ has the largest figure-of-merit over all the temperatures, and its highest value was $1.5{\times}$10$^{-4}$ $K^{-1}$ at 1145 K.5 K.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1095-1100
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• 2021

In this study, ITZO thin films were deposited on glass, sapphire, and PEN substrates by RF magnetron sputtering, and their electrical and optical properties were investigated. The resistivity of the ITZO thin film deposited on the glass and sapphire substrates was 3.08×10-4 and 3.21×10-4 Ω-cm, respectively, showing no significant difference, whereas the resistivity of the ITZO thin film deposited on the PEN substrate was 7.36×10-4 Ω-cm, which was a rather large value. Regardless of the type of substrate, there was no significant difference in the average transmittance of the ITZO thin film. Figure of Merits of the ITZO thin film deposited on the glass substrate obtained using the average transmittance in the absorption region of the amorphous silicon thin film solar cell and the absorption region of the P3HT : PCBM organic active layer were 10.52 and 9.28×10-3 Ω-1, respectively, which showed the best values. Through XRD and AFM measurements, it was confirmed that all ITZO thin films exhibited an amorphous structure and had no defects such as pinholes or cracks, regardless of the substrate type.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.443-450
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• 2021

After selecting a PES substrate with excellent thermal stability and optical properties among plastic substrates, a SiO₂ thin film was deposited as a buffer layer to a thickness of 20nm by plasma-enhanced chemical vapor deposition to compensate for the high moisture absorption. Then, the ITZO thin film was deposited by a RF magnetron sputtering method to investigate electrical and optical properties according to RF power. The ITZO thin film deposited at 50W showed the best electrical properties such as a resistivity of 8.02×10^-4 Ω-cm and a sheet resistance of 50.13Ω/sq.. The average transmittance of the ITZO thin film in the visible light region(400-800nm) was relatively high as 80% or more when the RF power was 40 and 50W. Figure of Merits (Φ_TC and FOM) showed the largest values of 23.90×10^-4 Ω^-1 and 5883 Ω^-1cm^-1, respectively, in the ITZO thin film deposited at 50W.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.1
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• pp.1-11
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• 2013

The Gongju Sanseong Traditional Market, the subject of this study, was formed in the early 1900's, and along with the development of Gongju, it has been constantly changed and expanded up until now. The Sanseong Traditional Market located in Gongju, the Korea's representative historic city, exhibits merits in the aspects as a city based on the symbolic significance of the city where it is located and historical characteristics; however, it also presents some problems as well in consideration of user convenience and accessibility. Thereupon, this study conducted literature review on traditional markets, field research with a field trip, and a survey in order to analyze the spatial characteristics of the market environment and grope for the methods of activation. The conclusion suggested through this is as written below: First, the changes of types regarding spatial use according to the modernization project of traditional markets are essential, so about the spatial use according to the spatial changes, it is needed to distribute it balancedly considering the central space of the market. Second, with the understanding of the spatial types of traditional markets, it is needed to build a plan for alternation in the types of physical space based on that. Third, it is necessary to suggest the methods of integrated spatial use among standing markets and 5-day markets. In particular, through the approaches from the aspects of architectural and urban design and through reasonable spatial planning, a systematic approach considering the convenience of the users and merchants using it as their living space should be prioritized. And lastly, it is needed to reorganize the space according to the physical and non-physical methods in order to figure out the methods of activating traditional markets in agricultural areas and minor cities. With the complex approaches above, we can grope for the methods of activating traditional markets.

• Asia-Pacific Journal of Business
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• v.11 no.3
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• pp.243-260
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• 2020

Purpose - This paper aims to investigate the properties of crude oil based derivative security (DLS) focusing on step-down type for comprehensive understanding of its risk. Design/methodology/approach - Kernel estimation is conducted to figure out statistical feature of the process of oil price. We simulate oil price paths based on kernel estimation results and derive probabilities of hitting the barrier and early redemption. Findings - The amount of issuance for crude oil based DLS is relatively low when base prices are below $40 while it is high when base prices are around $60 or $100, which is not consistent with kernel estimation results showing that oil futures prices tend to revert toward $46.14 and the mean-reverting speed is faster as oil price is lower. The analysis based on simulated oil price paths reveals that probability of early redemption is below 50% for DLS with high base prices and the ratio of the probability of early redemption to the probability of hitting barrier is remarkably low compared to the case for DLS with low base prices, as the chance of early redemption is deferred. Research implications or Originality - Empirical results imply that the level of the base price is a crucial factor of the risk for DLS, thus introducing a time-varying knock-in barrier, which is similar to adjust the base price, merits consideration to enhance protection for DLS investors.

• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.11-15
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• 2013

These days, the quality of goods is required to improve in the process of manufacturing the semiconductor through the short working hours and clean transportation. The non-contact transport device using magnetic levitation can be a solution in the manufacturing process. The non-contact transport device, using electromagnetic actuation, is the system that can actually transport them by only using attraction force from the electromagnetic source without authentic contact. Moreover, the system using electromagnetic force has a substantial number of benefits ranging from unrestricted design to unlimited expansion. Especially, the price is competitive. The non-contact transport device, using electromagnetic force, has another merits in controlling by giving the same amount of attraction force to ferromagnetic body. By controlling the currents given to coil, the operator is able to decide the direction of the transportation. In order to design the optimal system, we implemented five different things such as the presence of the links below the electromagnetic, the electromagnet changes due to coupling method, the change according to the thickness of the links below electromagnet, due to changes in between electromagnetic distance direction, and the size of the current. Through simulations and the optimum design, it seems to control easily and figure out the exact size of power. It might definitely be the non-contact transport that can sharply reduce tiny scratches and particles in the process of manufacturing the semiconductor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.355-360
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• 2012

In this paper, an stepped-impedance low pass filter(SI-LPF) of triangular-patch type is proposed. A SI-LPF designed according to the standard SI-LPF design procedure is folded as a right angled triangle. The figure of merits of this structure are the adjustabilities of the cut off frequency, the stopband and the attenuation pole frequency of the proposed LPF by varying the resultant slots after folding the SI-LPF compactly for miniaturization. The size of the fabricated LPF is $13.75mm{\times}6.875mm$, which is 24.4 % reduced one compared to that of the conventional SI-LPF. The measured results of the LPF show return loss of less than -10 dB at passband, insertion loss of less than -10 dB at stopband and wide stopband from 3.5 GHz to 10 GHz (about $3f_c$).

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.139-144
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• 2005

A rigorous research is underway in our team, for the design and development of high figure of merits (ZT= 1.5${\sim}$2.0) micro-thermoelectric coolers. This paper discusses the fabrication process that we are using for developing the $Sb_2Te_3-Bi_2Te_3$ micro-thermoelectric cooling modules. It describes how to obtain the mechanical properties of the thin film TEC elements and reports the results of an equation-based multiphysics modeling of the micro-TEC modules. In this study the thermoelectric thin films were deposited on Si substrates using co-sputtering method. The physical mechanical properties of the prepared films were measured by nanoindentation testing method while the thermal and electrical properties required for modeling were obtained from existing literature. A finite element model was developed using an equation-based multiphysics modeling by the commercial finite element code FEMLAB. The model was solved for different operating conditions. The temperature and the stress distributions in the P and N elements of the TEC as well as in the metal connector were obtained. The temperature distributions of the system obtained from simulation results showed good agreement with the analytical results existing in literature. In addition, it was found that the maximum stress in the system occurs at the bonding part of the TEC i.e. between the metal connectors and TE elements of the module.