• Title/Summary/Keyword: cycle stability

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Thermal and Electrochemical Studies of Tris(2,4,6-trimethoxyphenyl)Phosphine as a Flame Retardant Additive for Li-ion Battery (리튬이차전지 난연성 전해액 첨가제로서의 Tris(2,4,6-trimethoxyphenyl)Phosphine의 열적, 전기화학적 특성)

  • Ahn, Se-Young;Kim, Ke-Tack;Kim, Hyun-Soo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.12
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    • pp.1130-1134
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    • 2008
  • Thermal and electrochemical properties were discussed with tris(2,4,6-trimethoxyphenyl)Phosphine (TTMPP) as a flame retradant additive for Li-ion battery. TTMPP showed excellent thermal stability with charged cathodes. Addition of 1 wt.% of the additive to the electrolyte improved the thermal stability without damaging the performance of the battery. The oxygne evolution reaction delayed nearly by $60^{\circ}C$. The capacity retention ratio in cycle life tests of the battery with 1 wt.% TTMPP was slightly improved comparing to the no additive cells.

Deubiquitinase USP35 as a novel mitotic regulator via maintenance of Aurora B stability

  • Park, Jinyoung;Song, Eun Joo
    • BMB Reports
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    • v.51 no.6
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    • pp.261-262
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    • 2018
  • Aurora B is an important kinase involved in dynamic cellular events in mitosis. Aurora B activity is controlled by several post-translational modifications (PTMs). Among them, E3 ubiquitin ligase-mediated ubiquitination plays crucial roles in controlling the relocation and degradation of Aurora B. Aurora B, ubiquitinated by different E3 ligases, moves to the exact site for its mitotic function during metaphase-anaphase transition and is then degraded for cell cycle progression at the end of mitosis. However, how the stability of Aurora B is maintained until its degradation has been poorly understood. Recently, we have found that USP35 acts as a deubiquitinating enzyme (DUB) for Aurora B and affects its stability during cell division, thus being involved in the regulation of mitosis. In this review, we discuss the USP35-mediated deubiquitination of Aurora B and the regulation of mitotic progression by USP35.

Rotordynamic Design and Stability Prediction of 100 Watts Micro Power System (100 Watts 급 초소형 파워 시스템의 회전체 동역학적 설계 및 안정성 예측)

  • Kwak, Hyun-Duck;Lee, Yong-Bok;Ryu, Keun;Kim, Chang-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.459-464
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    • 2003
  • The Roordynamic feasibility of Micro Power System supported by air foil bearings is investigated. The Micro Power System is new portable power source based on brayton cycle, which consists of compressor, turbine, generator, and combustion chamber. In this paper, the analysis of Rotordynamic characteristics of Micro Power System is performed based upon the bearing equilibrium position, Campbell diagram and stability. As a result, it is demonstrated that the air foil bearings could be adopted well to the Micro Power System. However, for more stable operation at target running speed, the damping characteristics of air foil bearing should be enhanced.

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Improvement of the Stability of Lactobacillus casei YIT 9018 by Microencapsulation Using Alginate and Chitosan

  • Koo, Sun-Mo;Cho, Young-Hee;Huh, Chul-Sung;Baek, Young-Jin;Park, Ji-Yong
    • Journal of Microbiology and Biotechnology
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    • v.11 no.3
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    • pp.376-383
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    • 2001
  • Lactobacillus casei YIT 9018 was microencapsulated within alginate or alginate/chitosan double membrane using an air atomizer. Microbiological analysis revealed that the viability of encapsulated L. casei in gastric juice, hydrogen peroxide, and pepsin was 2-3 log cycle higher than that of the nonencapsulated cell. However, the encapsulated cells did not show a signifciant increase in survival when subjected to in virto high acid and 0.6% bile salt condition. Alginate-encapsulated, alginate/chitosan-encapsulated, and nonencapsulated cells were stored at different temperatures eencapsulated cells showed similar stability at $4^{\circ}C$. However, at $22^{\circ}C$, the alginate/chitosan-encapsulted cell was the most stable.

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Comparison of Small Signal Stability Analysis Methods in Complex Systems with Switching Elements

  • Kim, Deok Young;Meliiopoulos, A.P.Sakis
    • KIEE International Transactions on Power Engineering
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    • v.4A no.2
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    • pp.79-83
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    • 2004
  • A new small signal stability analysis method for eigenvalue analysis is presented. This method utilizes the Resistive Companion Form (RCF) for the computation of the transition matrix over a specified time interval, which corresponds to a single cycle operation of the system. This method is applicable to any system, with or without switching element. An illustrative example of the method is presented and the eigenvalues are compared with those of the conventional state space method (analog) in order to demonstrate the accuracy of the proposed eigenvalue analysis method. Also, the variations of oscillation modes that are caused by the switching operation can be precisely analyzed using this method.

The Study on the Behavior of Curved CWR Track under Thermal Load (곡선부 장대레일 궤도의 거동 특성에 관한 연구)

  • Lee, Won-Gyeong;Sung, Deok-Yong;Kim, Man-Cheol;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.426-436
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    • 2006
  • The use of the CWR track has increased consistently in the worldwide. Because the use of CWR track not only reduces the track maintenance cost, noise and vibration, but increases the life cycle of track components. Therefore, to increase train speed, improve riding condition and secure running stability, the necessity of study on making CWR is increasing. This study includes the development of a thermal buckling theory in the evaluation of curved track stability. The lateral stability of curved CWR is studied for track buckling prevention through the parameter studies. It studied the lateral buckling of the curved CWR track on the 3-D nonlinear analysis. The parameters include rail size, cant, track curvature.

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Stability Analysis and Design of the Open Cycle Liquid Rocket Engine (개방형 액체로켓엔진의 안정성 분석 및 설계)

  • Jung Young-Suk;Lee Han-Ju;Lim Seok-Hee;Cho Kie-Joo;Cho Gyu-Sik;Oh Seung-Hyub
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.235-238
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    • 2004
  • In the present study, the stability of turbopump through the rotor dynamics was analyzed with the location analysis method of the pole of characteristic equation for stability analysis of LRE and the design guideline for turbopump was presented according to design requirements of the LRE.

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Stability of Li[Co0.1Ni0.15Li0.2Mn0.55]O2 Cathode Material for Lithium Secondary Battery (리튬 2차 전지용 Li[Co0.1Ni0.15Li0.2Mn0.55]O2 양극물질의 안정성 고찰)

  • Park, Yong-Joon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.5
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    • pp.443-449
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    • 2007
  • The structural and thermal stability of $Li[Co_{0.1}Ni_{0.15}Li_{0.2}Mn_{0.55}]O_2$ electrode during cycling process was studied. The sample was prepared by simple combustion method. Although there were irreversible changes on the initial cycle, O3 stacking for $Li[Co_{0.1}Ni_{0.15}Li_{0.2}Mn_{0.55}]O_2$ structure was retained during the first and subsequent cycling process. Impedance of the test cell was decreased after the first charge-discharge process, which would be of benefit to intercalation and deintercalation of lithium ion on subsequent cycling. As expected, cycling test for 75 times increased impedance of the cell a little, instead, thermal stability of $Li[Co_{0.1}Ni_{0.15}Li_{0.2}Mn_{0.55}]O_2$ was improved. Moreover, based on DSC analysis, the initial exothermic peak was shifted to high temperature range and the amount of heat was also decreased after cycling test, which displayed that thermal stability was not deteriorated during cycling.

Evaluation of Postural Stability according to characteristics of Electrical Stimulation on the ankle muscles (족관절 근육에 인가한 전기 자극의 특성에 따른 자세안정성 평가)

  • Lee, S.Y.;Yu, M.;Kim, N.G.;Kim, D.W.
    • Journal of Biomedical Engineering Research
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    • v.30 no.6
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    • pp.521-528
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    • 2009
  • This study is about to evaluation of postural stability according to characteristics of electrical stimulation on the ankle muscles. We measured body sway(center of pressure, COP) when various parameters of electrical stimulation was applied to ankle muscles in stable and unstable posture. Subjects consisted of 10 young adults, and electrical stimulation was delivered on right and left of tibialis anterior and Achilles tendon. The body sway was measured during electrical stimulation of three duty cycle and frequencies in stable posture and three amplitudes of sensory threshold in unstable posture. Consequently, the COP Shift is higher during electrical stimulation of 1/30(duty ratio) and 100Hz(frequency) in stable posture. In unstable posture, 100% amplitude of sensory threshold induced postural stability. These findings are important for the rehabilitation system of postural stability and the use of electrical stimulation as somatosensory information.

Mesh Stability Study for the Performance Assessment of a Deep Geological Repository Using APro

  • Hyun Ho Cho;Hong Jang;Dong Hyuk Lee;Jung-Woo Kim
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.21 no.2
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    • pp.283-294
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    • 2023
  • APro, developed in KAERI for the process-based total system performance assessment (TSPA) of deep geological disposal systems, performs finite element method (FEM)-based multiphysics analysis. In the FEM-based analysis, the mesh element quality influences the numerical solution accuracy, memory requirement, and computation time. Therefore, an appropriate mesh structure should be constructed before the mesh stability analysis to achieve an accurate and efficient process-based TSPA. A generic reference case of DECOVALEX-2023 Task F, which has been proposed for simulating stationary groundwater flow and time-dependent conservative transport of two tracers, was used in this study for mesh stability analysis. The relative differences in tracer concentration varying mesh structures were determined by comparing with the results for the finest mesh structure. For calculation efficiency, the memory requirements and computation time were compared. Based on the mesh stability analysis, an approach based on adaptive mesh refinement was developed to resolve the error in the early stage of the simulation time-period. It was observed that the relative difference in the tracer concentration significantly decreased with high calculation efficiency.