• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1813-1819
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• 2012

This paper presents vector magnetic properties of an electrical steel sheet (ESS) employed for electric machine and iron loss analysis considering the vector magnetic properties of the ESS. The vector magnetic properties of the ESS are measured by using a two-dimensional single sheet tester and modeled by an E&S vector hysteresis model to be applied to finite element method. The finite element analysis considering the vector magnetic properties is applied to iron loss analysis of a three-phase induction motor model, and the influences of the vector magnetic properties on the iron loss distribution are verified by comparing with numerical results from a typical B-H curve model.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.907-909
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• 2009

Low voltage operated top gated polymer transistors were fabricated with a high permittivity polymer, P(VDF-TrFE) and F8T2 as a gate dielectric and semiconducting layer, respectively. The operating voltage of transistors was effectively reduced under -10 V and typical threshold voltages were as low as -1 ~ -4 V with the reasonable charge carrier mobility of $10^{-3}cm^2$/Vs for the amorphous polymer. The large hysteresis in transfer curve was improved effectively by annealing at low temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.367-370
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• 1998

In this paper, based on the research of high temperature YBCO superconductor, using the Yb instead of Y, with the YbBCO superconductor powder which was combined by means of conventional solid reaction, textured directional crystal was prepared by MCP method and the character was analyzed. Mixing the starting elements and calcining at 890$^{\circ}C$, 900$^{\circ}C$, 910$^{\circ}C$, single phase YbBCO, Yb$_2$BaCuO$\sub$5/ and BaCuO$\sub$2/ were certified. And from the powder which was calcined at 900$^{\circ}C$ the, sample which became texture-growth by MCP method was well oriented. The result of DTA measurement, the fusing point of YbBCO superconductor and it\`s critical current was measured to be 979$^{\circ}C$, 87K respectively. The critical current density was obtained at the value of 700A/$\textrm{cm}^2$(77K. 0H) calculated by Bean's Model using the measured hysteresis curve of VSM.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.128-135
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• 1998

In this study, the unseating failure of the bridge spans under seismic excitations is examined by investigation the nonlinear response behaviors of the bridge system with reinforced concrete piers. To reduce the computational effort and to consider the effect of the foundation motions, a simplified 3 degree-of-freedom model is proposed, which retains the dynamic characteristics of the original bridge motions in concern. To imply the nonlinear behaviors of the RC piers to the system. a hysteresis model is utilized from the calculated force-deformation curve for the piers. The statistical characteristics of the maximum response displacements are obtained from the simulation results of 1000 time history analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.173-179
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• 1998

The piping system of a power plant suffers not only thermal expansion according to the temperature variation, but also many kinds of load: steady state vibrations due to the equipment operation or fluid flow, and transient vibrations due to the earthquake or explosion, etc. The snubbers are usually installed on the piping system to allow thermal expansion, and to reduce dynamic responses. Most snubbers are kinds of hydraulic and mechanical type, which can be degraded by leakage and abrasion, and required much cost for maintenance and replacement. Recently the wire rope type snubbers are developed and applied to the power plant, and proved as effective to reduce piping system vibration. Wire rope type snubber uses the bending rigidity and energy dissipation properties of ropes. This paper presents the procedure of design, and the method to apply hysteresis curve to the dynamic response analysis. Experiments were also conducted to confirm design results.

• Steel and Composite Structures
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• v.27 no.6
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• pp.675-689
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• 2018

Buckling-restrained braces (BRBs) have received considerable attention in seismic design of various types of structures. Conventional BRBs are composed of steel core and surrounding steel tube filled with concrete. Eliminating the steel tube can be advantageous to BRB. In this study the idea of replacing the steel tube by CFRP layers in BRBs is proposed. The advantages of this type of BRB are mentioned, and its design criteria are introduced. The construction procedure of two BRB specimens is described. The specimens are uniaxially tested based on moderate, and severe earthquake levels and the performance of the specimens is investigated. The backbone curves resulted from the hysteresis curve are presented for the design proposes. The results of this study show that CFRP layers can effectively provide the expected performance of the encasing, and the proposed BRB can be considered a viable alternative to the conventional BRBs.

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.162-164
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• 2012

In this study, we fabricate Pt nanoparticle (NP)-embedded MOS capacitors at room temperature and investigate their memory characteristics. The Pt NPs are separated from each other and situated between the tunnel and control oxide layers. The average size and density of the Pt NPs are 4 nm and $3.2{\times}10^{12}cm^{-2}$, respectively. Counterclockwise hysteresis with a width of 3.3 V is observed in the high-frequency capacitance-voltage curve of the Pt NP-embedded MOS capacitor. Moreover, more than 93% of the charge remains even after $10^4$ s.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1106-1109
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• 1993

Ferroelectric thin films of PZT with differnt Zr/Ti ratio were prepared by sol-gel processing and annealed by rapid-thermal-annealing at $500^{\circ}C-700^{\circ}C$ for 10sec-1min. The structure of the annealed films were examined by X-ray diffraction and SEM. Maximum remnant polarization of 10.24 ${\mu}m/cm^2$ and coercive field of 70 KV/cm were obtained from hysteresis curve or the film.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.209-211
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• 1994

X/65/35 PLZT ferroelectric thin films were fabricated by sol-gel processing. Thin films were crystallized after rapid thermal processing at $750^{\circ}C$ for 5 min. The microstructure, the relative dielectric constant the curie point, the hysteresis curve and the optical transmittance of thin films were investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.360-363
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• 2003

In this paper, we investigated SiNx film as a buffer layer of TFT-FRAM. Buffer layers were prepared by two step process of a $N_2$ plasma treatment and subsequent $SiN_x$ deposition. By employing $N_2$ plasma treatment, interface traps such as mobile charges and injected charges were removed, hysteresis of current-voltage curve disappeared. After $N_2$ plasma treatment, a leakage current was decreased about 2 orders. From these results, it is possible to perform the plasma treating process to make a good quality buffer layer of MFIS-FET or capacitor as an application of non-volatile memory.