• Title/Summary/Keyword: GPC

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Evaluation of Aging Characteristics of Selected PMA using HP-GPC (HP-GPC를 이용한 폴리머개질 아스팔트의 노화특성 분석)

  • Kim, Kwang-Woo;Doh, Young-Soo;Amerkhanian, Serj N.
    • International Journal of Highway Engineering
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    • v.6 no.2 s.20
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    • pp.15-24
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    • 2004
  • Oxidation causes increment of the quantity of large molecular size or LMS in asphalt and is a major reason for hardening of asphalt binder. An extended service life of pavement on a road is expected by reducing oxidation of binder. Oxidation of binder occurs during hot mixing with aggregates before placement on road and then during in-service after the asphalt pavement is constructed. Quantitative increase of LMS as result of aging after RTFO and PAV was analyzed based on the data from high-pressure gel-permeation chromatography (HP-GPC). Polymer modified asphalt (PMA) after RTFO procedure showed 20-30% increment in LMS and then after PAV procedure more than twice, although the percentage of increment was different according to asphalt brand and grade. The PMAs containing LDPE or SBS, which showed a great mechanical property improvement in previous studies, were selected for characterizing PMA aging In this study. Considerably reduced increment of LMS was observed from the PMA containing LDPE after RTFO and PAV procedures. The GPC result showing the binder with less LMS increment means that the asphalt while being mixed with LDPE was aged less during the aging treatment. The dispersed particle of LDPE in asphalt cement seems to disturb oxidative aging reaction and evaporation.

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Generalized Predictive Control for Multiloop Processes (다중루프 공정을 위한 일반형 예측 제어)

  • 김성우;김병국
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.7
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    • pp.66-75
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    • 1994
  • In this paper, we present a new GPC algorithm for plants with known disturbances. Also, based on the above algorithm unidirectional and bidirectional predictive controllers have been proposed concerning plants with input couplings between subprocesses. These predictive control algorithms can be applied to many industrial processes as a multiloop controllers. Simulation results show that the proposed algorithm has improved performance and computing time compared to conventional GPC algorithm.

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A robust generalized predictive control which guarantees $H_{\infty}$ norm bounds ($H_{\infty}$노옴조건을 만족하는 강인한 일반형예측제어기)

  • 이영일;김용호;권욱현
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.556-559
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    • 1996
  • In this paper, we suggest a H center .inf. generalized predictive control(H center GPC) which guarantees $H_{\infty}$-norm bounds. THe suggested control is obtained by solving the min-max problem in nonrecursive forms. The stability conditions of the suggested control are derived in a somewhat simple form and it is not required for the derived solution to be a saddle point solution. It is also shown that the suggested control guarantees the $H_{\infty}$-norm bounds under the same conditions of stability.

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Reliable stabilizing multi-controller for steam generator level control (증기발생기 수위제어를 위한 다중 안정화 제어기 설계)

  • 권현진;박상현;이상정;함창식
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.1229-1232
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    • 1996
  • This paper proposes the passive redundancy algorithm of multi-controller structure applicable to the steam generator level control system in the low power operating range. In the passive redundancy scheme of multi-controller structure, two suitable controllers exist if the plant is strongly stabilizable. One of the two controllers can be selected arbitrarily only if it is stable. In particular, this paper shows that the passive redundancy scheme can be efficiently used with PID and GPC control algorithms through simulation studies on the control of the steam generator.

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GPC 기법을 이용한 자기동조 PID 제어기 설계

  • 윤강섭;이만형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.04b
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    • pp.326-329
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    • 1995
  • PID control has been widely used for real control system Further, there are muchreasearches on control schemes of tuning PID gains. However, there is no results for discrete-time systems with unknown time-dealy and unknown system parameters. On the other hand, Generalized predictive control has been reported as a useful self-tuning control technique for systems with unknown time-delay. So, in this study, based on minimization of a GPC criterion, we present a self-tuning PID control algorithm for unknown parameters and unknown tiem-delay system. A numerical simulation was presented to illuatrate the effectiveness of this method.

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A Study on Dielectric Strength and Insulation Properly of PDMS (실리콘 폴리머의 내전압 및 절연특성에 관한 연구)

  • 지원영
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.11
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    • pp.941-946
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    • 2001
  • The fundamental study on HTV silicone for insulation material has been performed. In order to estimate the chemical behavior of siloxane under high voltage, H-NMR, GPC and vinyl contents measurement were used. As an experimental results, after high voltage stress, the molecular weight of siloxane are increased, the vinyl contents of siloxane are decreased. The dielectric strength of vinyl group containing siloxane was lower than only methyl containing siloxane.

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Methodology for Modifying Aging Condition of Hot-mix Recycled Asphalt Mixture (가열 재생혼합물의 노화특성 개선을 위한 연구)

  • Kim, Kwang-Woo;Hong, Sang-Ki;Lee, Gi-Ho;Doh, Young-Soo
    • International Journal of Highway Engineering
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    • v.7 no.1 s.23
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    • pp.1-9
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    • 2005
  • This is a basic research for producing hot-mix recycled asphalt mixtures and suggesting methods for solving quality problems, if any. Various mixing methods are introduced to mate aging evenly between old and virgin aggregates and to improve aging conditions. Gel-permeation chromatography(GPC) analysis was performed to evaluate aging of binders coated on coarse aggregates and a matrix separately. Round-shaped aggregates(13m gravel) were used in manufacturing mixtures for analysis of aging levels in recycled mixtures. It was found out that there was significant difference in aging levels between the binder coated on RAP's coarse aggregates and on virgin aggregates in a recycled mixture. The difference in the aging level was reduced by modifying mixing method(RAP and virgin binders were mixed first and then virgin aggregates were introduced). Among A to E mixing methods studied, the D was turned out to be the best.

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Effect of Extrusion-Cooking on the Molecular Structure and Alcohol Yield of Wheat Starch (압출조리에 의한 밀가루 전분질의 분자구조 변화와 알콜발효 효율에 관한 연구)

  • Lee, Cherl-Ho;Kim, Gi-Myung;Kim, Ji-Young;Lim, Jae-Gak
    • Korean Journal of Food Science and Technology
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    • v.23 no.6
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    • pp.683-688
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    • 1991
  • Wheat flour was extruded by a single-screw extruder, and used for the ethanol production of takju. The molecular structure and enzymic susceptability of extruded starch were compared to those of steam cooked one. The gel permeation chromatographic pattern of wheat flour extrudates was not significantly different from those of raw and steam cooked starches. However, the conversion rate of extruded starch into maltose by ${\alpha}-amylase$ hydrolysis was significantly faster than those of raw ad steamed starch. The molecular weight of starch estimated from GPC pattern and the intrinsic viscosity were remarkably reduced by extrusion cooking followed by the enzymic hydrolysis for 30 min, while steam cooking and enzymic hydrolysis for 30 min did not change them significantly. Extrusion-cooked flour produced alcohol 26% higher than that of steamed flour in the laboratory takju fermentation, and 10% more alcohol in the pilot plant scale takju production.

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Production and Characterization of Selenium Peptide from Saccharomyces Cerevisiae (효모를 이용한 selenium peptide 생산 및 특성 연구)

  • 김은기;김영옥;이정옥;이백석
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.1
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    • pp.73-77
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    • 2004
  • Selenium containing peptide was produced by culturing yeast with selenium, Selenium was broadly incorporated in the various size of proteins based on the GPC analysis of the total yeast protein. The ratio of selenium to protein increased with the concentration of added selenium in the culture medium. Antioxidant activity (glutathione peroxidase-like activity) was proportional to the concentration of selenium concentration in the peptide. Different size of proteins were obtained by hydrolyzing the total yeast protein by protease XIV. Average molecular weight of selenium peptide was analyzed by GPC. Glutathione peroxidase (GPx) activity of the selenium peptide increased as the size of peptide decreased. Sodium selenite had strong inhibition on the yeast growth than sodium selenate. The ratio of selenium to protein was higher with sodium selenate than with sodium selenite. These results showed the potentials of selenium peptide production by yeast cultivation.

Isolation of Angiotensin Converting Enzyme Inhibitor from Doenjang (전통된장으로부터 Angiotensin Converting Enzyme 저해물질의 분리)

  • Kim, Seung-Ho;Lee, Yun-Jin;Kwon, Dae-Young
    • Korean Journal of Food Science and Technology
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    • v.31 no.3
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    • pp.848-854
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    • 1999
  • Inhibitory compounds of angiotensin converting enzyme (ACE) were separated from Doenjang (traditional Korean fermented soybean paste). Water extracts from Doenjang which showed ACE inhibitory activity were separated with gel permeation chromatography (GPC), in which two fractions with high ACE inhibitory activities were obtained. The first fraction from GPC was further isolated by semi-preparative reverse phase preparative-HPLC (high performance liquid chromatography) and 2-dimensional electrophoresis/thin layer chromatography (TLC). The purified spot had molecular weight of 759 daltons and ninhydrin-positive non-peptide. The second fraction from GPC was also further isolated by semi-preparative reverse phase HPLC and $NH_2-column$ HPLC. One fraction with high ACE inhibitory activity was purified and characterized. Molecular weight of this fraction by LC-MS was 272.34 daltons. The active fraction was identified as Arg-Pro with ACE $IC_{50}$ of $92\;{\mu}M$.

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