• Title/Summary/Keyword: Bi-stability

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A study on the Stability of Bi-based Superconducting Wires cooled by a Cryocooler (저온냉동기로 냉각된 Bi 계 초전도선재의 안정성 연구)

  • 이호진;홍계원
    • Electrical & Electronic Materials
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    • v.10 no.4
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    • pp.320-326
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    • 1997
  • The stability of Bi-based superconducting wires cooled by a cryocooler was studied by considering the temperature dependency of critical current and electrical resistivity. The critical current measured in 23 K was about 7 times higher than that measured in liquid nitrogen of 77 K. The stability behavior of Bi based multifilament wires subjected to a thermal disturbance, which was simulated with a electric heater, was investigated by measuring the variation of voltage drop with time. Current sharing was occurred, and recovery to superconductivity was measured in the wire after removing heater power.

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Stability Against Heat Pulse for Bi-2223 HTS Pancake Coils with Different Ag/SC Ratio (은비가 다른 Bi-2223 고온초전도 팬케이크 코일의 히트펄스에 대하 안정성)

  • 장현만;오상수;하홍수;하동우;류강식;김상현
    • Progress in Superconductivity and Cryogenics
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    • v.1 no.2
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    • pp.43-48
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    • 1999
  • The normal zone propagation (NZP) velocity and V-I characteristics of two Bi-2223 pancake coils with different Ag/SC ratio were investigated based on the experimental results and broad resistive transition were obesved in two coils. The measured NZP velocity of coil was found to be faster due to increase of Ag/SC ratio, and agree well with calculated data from two dimensional heat balance equation.

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The Phse Stability and the Electrical Properties of $3Bi_2O_3.WO_3$ Solid Electrolyte ($3Bi_2O_3.WO_3$ 고체전해질의 상안정성과 전기적 특성)

  • 백현덕;이윤직;박종욱
    • Journal of the Korean Ceramic Society
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    • v.32 no.2
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    • pp.248-256
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    • 1995
  • The electrical conducton in the sintered 3Bi2O3.WO3 solid electrolyte was investigated by measuring the conductivity and ionic transport number. The electrical conductivity was about three to ten times higher than that of YSZ at temperatures between 300 and 80$0^{\circ}C$. D.C. polarization method confirmed that 3Bi2O3.WO3 was predominantly an ionic conductor. Unlike the instability of high conductive fcc phase in the rare-earth oxide-Bi2O3 or Y2O3-Bi2O3 systems at temperature below $700^{\circ}C$, fcc phase in the 3Bi2O3.WO3 exhibited no transformation even after annealing over 900 hrs at 600 and $650^{\circ}C$. Two samples which had different grain sizes showed almost the same conductivity. This result suggests that the electrical properties of grain and grain boundry were very similar.

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Multi-Finger 3D Landmark Detection using Bi-Directional Hierarchical Regression

  • Choi, Jaesung;Lee, Minkyu;Lee, Sangyoun
    • Journal of International Society for Simulation Surgery
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    • v.3 no.1
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    • pp.9-11
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    • 2016
  • Purpose In this paper we proposed bi-directional hierarchical regression for accurate human finger landmark detection with only using depth information.Materials and Methods Our algorithm consisted of two different step, initialization and landmark estimation. To detect initial landmark, we used difference of random pixel pair as the feature descriptor. After initialization, 16 landmarks were estimated using cascaded regression methods. To improve accuracy and stability, we proposed bi-directional hierarchical structure.Results In our experiments, the ICVL database were used for evaluation. According to our experimental results, accuracy and stability increased when applying bi-directional hierarchical regression more than typical method on the test set. Especially, errors of each finger tips of hierarchical case significantly decreased more than other methods.Conclusion Our results proved that our proposed method improved accuracy and stability and also could be applied to a large range of applications such as augmented reality and simulation surgery.

Development of a Formic Acid Fuel Cell Anode by Multi-layered Bismuth Modification (Bismuth를 이용한 다층구조의 개미산 연료전지 연료전극 개발)

  • Kwon, Youngkook;Uhm, Sunghyun;Lee, Jaeyoung
    • Korean Chemical Engineering Research
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    • v.46 no.4
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    • pp.697-700
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    • 2008
  • The underpotential deposited Bi on Pt($Bi_{upd}/Pt$) anode for formic acid fuel cells (FAFCs) was developed using multi-layered preparation method for better electrocatalytic utilization of Pt. The electron probe microanalysis (EPMA) result indicated that $Bi_{upd}$ remains through the catalyst layer during stability test. In performance test, the multilayered $Bi_{upd}$ on Pt black showed superior performance by approximately 200 mV at current density of $150mA/cm^2$ compared with PtRu black anode catalyst. Based on preparation condition of $Bi_{upd}/Pt$ black, carbon supported $Bi_{upd}/Pt/C$ electrode was prepared and it showed enhanced performance and stability.

A Case Study of High Capacity Bi-Directional High Pressure Pile Load Test (초고용량 양방향 말뚝재하시험(BDH PLT) 수행사례 분석)

  • Kim, Sang-Il;Lee, Min-Hee;Jeong, Sung-Min;Jeong, Eun-Taeg;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1156-1163
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    • 2010
  • The bi-directional high pile load test(BDH PLT) does not have weaknesses found in the existing bi-directional low pile load test(BDL PLT); it has strong economics, is unbound by load capacity limit and secures quality stability of working piles. In this study, Verification the field found a very high capacity level of stability and reliability of the BDH PLT, as well as outstanding field applicability. Field verifications reaffirmed the advantage of the BDH PLT device, which was capable of loading 90 MN capacities as maximum. It was also found to be durable enough to load high capacity with ease.

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A Study of Dynamic Properties of Graphene-Nanoribbon Memory (그래핀 나노리본 메모리의 동적 특성에 대한 연구)

  • Lee, Jun Ha
    • Journal of the Semiconductor & Display Technology
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    • v.13 no.2
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    • pp.53-56
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    • 2014
  • In this work, we investigate the operational properties of this proposed device in detail via classical MD simulations. The bi-stability of the GNF(Graphene Nano-flake) shuttle encapsulated in bi-layer GNR could be achieved from the increase of the attractive energy between the GNRs when the GNF approached the edges of the GNRs. This result showed the potential application of the nano-electromechanical GNR memory as a NVRAM.