• Title/Summary/Keyword: J48

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Rapid Charger for 48V Lead-acid Battery (48V용 납축전지 급속 충전기)

  • Ahn, S.H.;Jang, S.R.;Ryoo, H.J.;Mo, S.C.;Oh, S.W.;Park, C.J.
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.945_946
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    • 2009

  • This paper describes the development of the rapid battery charger for lead-acid battery. Due to heat which is caused by increased internal resistance during charging, it is difficult to increase charging current for the lead-acid battery. In this paper, the rapid charging algorithm which apply short discharging pulse current during charging procedure is developed and it makes the ion layer, which is generated during charging time, disappeared into electrolyte. The prototype battery charger based on resonant converter is developed for 48V battery charger and test procedure is introduced.

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On Generalized Integral Operator Based on Salagean Operator

  • Al-Kharsani, Huda Abdullah
    • Kyungpook Mathematical Journal
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    • v.48 no.3
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    • pp.359-366
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    • 2008

  • Let A(p) be the class of functions $f\;:\;z^p\;+\;\sum\limits_{j=1}^{\infty}a_jz^{p+j}$ analytic in the open unit disc E. Let, for any integer n > -p, $f_{n+p-1}(z)\;=\;z^p+\sum\limits_{j=1}^{\infty}(p+j)^{n+p-1}z^{p+j}$. We define $f_{n+p-1}^{(-1)}(z)$ by using convolution * as $f_{n+p-1}\;*\;f_{n+p-1}^{-1}=\frac{z^p}{(1-z)^{n+p}$. A function p, analytic in E with p(0) = 1, is in the class $P_k(\rho)$ if ${\int}_0^{2\pi}\|\frac{Re\;p(z)-\rho}{p-\rho}\|\;d\theta\;\leq\;k{\pi}$, where $z=re^{i\theta}$, $k\;\geq\;2$ and $0\;{\leq}\;\rho\;{\leq}\;p$. We use the class $P_k(\rho)$ to introduce a new class of multivalent analytic functions and define an integral operator $L_{n+p-1}(f)\;\;=\;f_{n+p-1}^{-1}\;*\;f$ for f(z) belonging to this class. We derive some interesting properties of this generalized integral operator which include inclusion results and radius problems.

  • https://doi.org/10.5666/KMJ.2008.48.3.359 인용 PDF

Study on the Non-isothermal Crystallization Behavior of Polypropylene/Corn Starch-MB Blends (폴리프로필렌/옥수수전분 블렌드의 비등온결정화 거동 연구)

  • Kim, Youn-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.5
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    • pp.1125-1129
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    • 2008

  • Polypropylene (PP)/corn starch master batch(starch-MB) blends with different PP compositions of 90, 80, 70, and 60 wt% were prepared by melt compounding at $200^{\circ}C$, using lab scale Brabender mixer. The chemical structures, thermal properties and non-isothermal crystallization behavior of the PP/starch-MB blends were investigated by FT-infrared spectrometry (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). The fabrication of the PP/starch-MB blend was confirmed by the existence of hydroxy group in FT-IR spectrum. There was no district change in melting temperature and melting enthalpy, and TGA curve indicates a decrease in degradation temperature with starch-MB content. The non-isothermal crystallization process was analyzed using by Avrami equation. The Avrami exponents were in the range of 2.71-3.97 for PP and 1.48-1.99 for PP/starch-MB blonds. The activation energies calculated by Kissinger method were 233 kJ/mol for PP, 484 kJ/mol for PP90, 541 kJ/mol for PP80, 553 kJ/mol for PP70, and 422 kJ/mol for PP60.

  • https://doi.org/10.5762/KAIS.2008.9.5.1125 인용 PDF

ω-MODULES OVER COMMUTATIVE RINGS

  • Yin, Huayu;Wang, Fanggui;Zhu, Xiaosheng;Chen, Youhua
    • Journal of the Korean Mathematical Society
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    • v.48 no.1
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    • pp.207-222
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    • 2011

  • Let R be a commutative ring and let M be a GV -torsionfree R-module. Then M is said to be a $\omega$-module if $Ext_R^1$(R/J, M) = 0 for any J $\in$ GV (R), and the w-envelope of M is defined by $M_{\omega}$ = {x $\in$ E(M) | Jx $\subseteq$ M for some J $\in$ GV (R)}. In this paper, $\omega$-modules over commutative rings are considered, and the theory of $\omega$-operations is developed for arbitrary commutative rings. As applications, we give some characterizations of $\omega$-Noetherian rings and Krull rings.

  • https://doi.org/10.4134/JKMS.2011.48.1.207 인용 PDF KSCI

Improved Double Connected Voltage Source Inverter for Reducing Harmonics Involved in Output Voltage (출력측 고조파 저감을 위한 개선된 이중 접속 전압원 인버터)

  • Yoo, J.J.;Chung, T.J.;Han, W.Y.
    • Electronics and Telecommunications Trends
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    • v.8 no.4
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    • pp.37-48
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    • 1993

  • 본 고에서는 출력측에 함유된 고조파를 저감시키기 위하여 2 중 접속 전압원 인버터를 구성하였다. 이 시스템은 기존의 2 중 접속 12스텝 전압원 인버터에 단권 변압기와 복수개의 스위칭 소자로 구성된 탭 변환 회로를 부가하여 이를 스위칭 제어함으로써 인버터 출력의 스텝 수를 증가시켜 출력측 고조파를 저감시킬 수 있는 방법을 제시하였다.

  • https://doi.org/10.22648/ETRI.1993.J.080404 인용 PDF