• 제목/요약/키워드: h-stability

검색결과 5,110건 처리시간 0.041초

NFL-$H_{\infty}$/SMC 의 안정도 증명 : Part 4 (Stability Proof of NFL-$H_{\infty}$/SMC : Part 4)

  • 이상성;박종근;이주장
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 하계학술대회 논문집 C
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    • pp.982-984
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    • 1998
  • In this paper, a stability proof of the closed-loop stability for the nonlinear feedback linearization-$H_\infty$/sliding mode controller (NFL-$H_\infty$/SMC) is done by a Lyapunov function candidate using an addition form of the sliding surface vector and the estimation error.

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Investigation of muscle-specific beef color stability at different ultimate pHs

  • Wu, Shuang;Han, Jina;Liang, Rongrong;Dong, Pengcheng;Zhu, Lixian;Hopkins, David L.;Zhang, Yimin;Luo, Xin
    • Asian-Australasian Journal of Animal Sciences
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    • 제33권12호
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    • pp.1999-2007
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    • 2020
  • Objective: This study was aimed to investigate the muscle-specific beef color stability at normal and high ultimate pHs. Methods: The impact of muscle (Longissimus lumborum [LL] vs psoas major [PM]) and pH (normal ultimate pH [Np] vs high pH dark cutting beef [Hp]) on color stability, indicated by basic color traits, metmyoglobin reducing activity (MRA) and oxygen consumption (OC), as well as the lipid oxidation, were determined over 7 days of display at 4℃. Results: Hp-LL had the highest pH (6.92), followed by Hp-PM (6.01), Np-PM (5.76), and Np-LL (5.52). Hp-LL had increased (p<0.05) a, chroma and % oxymyoglobin during display. Hp-LL also had the highest metmyoglobin (MMb) reducing activity and OC among all the samples, thus, the greatest color stability, although very dark throughout storage, with lowest values for lightness (L) and yellowness (b). Np-LL also exhibited relatively high color stability, as a result of its lower % MMb and OC and higher MRA than psoas muscle samples. The 0.2 unit difference of the pH between Hp and Np psoas muscle, resulted in the difference of the color intensity, not the color stability. Interestingly, high pH psoas muscle (Hp-PM) did not have better color stability than Np-PM, and in fact had lower color stability than even Np-LL. The similar level of OC and lipid oxidation cannot explain the difference in color stability between Hp-PM and Np-LL. Conclusion: The Hp does not always show better color stability compared with Np beef, which depends on the muscle type. The balance of MRA and OC is important to keep the color in great intensity and stability in the meantime.

현탁액중 Mebendazole의 안정성 (A Stability of Mebendazole in Suspensions)

  • 한관섭;용군호;김길수;허영헌
    • 약학회지
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    • 제20권1호
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    • pp.27-31
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    • 1976
  • The stability of a newly introduced anthelmintic, mebendazole, in sweetened and aqueous suspension was tested by the accelerated temperature method and the effect of pH on the stability of mebendazole was studied. Mebendazole in aqueous and sweetened suspension was very stable at the pH range from 4 to 8.

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한국산 유색감자 색소의 특성 및 안정성에 관한 연구 (Studies on Characteristics and Stability of Anthocyanin Pigment Extracted from Korean Purple - Fleshed Potatoes)

  • 박홍주;전태욱;이성현;조용식;조수묵;장규섭
    • 한국식품영양과학회지
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    • 제33권9호
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    • pp.1544-1551
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    • 2004
  • 유색 감자(PL-6, PL-28, PL-31과 Jasim)에 함유된 수용성 색소인 anthocyanin의 pH, 당, ascorbic acid, 유기산과 광원에 대한 색소 안정성을 조사하였다. pH는 유색감자의 anthocyanin 색소 안정성에 영향을 주는 것으로 나타났는데, pH가 낮을수록 색도가 높고 안정하였으며 pH가 높아질수록 색소 파괴가 많아지는 경향을 나타내었다. 유색 감자의 anthocyanin 색소에 당 첨가 시 저장 기간동안 점차적으로 색소가 약간 감소하는 것으로 나타났다. Tartaric, citric, succinic acid와 같은 대부분의 유기산은 anthocyanin 색소의 안정성을 개선시킨 반면 malic, malonic acid는 색소의 안정성을 감소시켰다. 유기산 중 하나인 ascorbic acid만을 첨가했을 때 anthocyanin 색소 안정성은 계속 감소하였으나 thiourea를 함께 사용한 경우 anthocyanin 색소의 안정성 유지에 효과가 있었다. 암실, 형광 그리고 햇빛에 대한 유색감자 anthocyanin 색소의 안정성은 점차 감소하며 빛으로부터 색소를 차단함으로서 색소분해를 최소화할 수 있을 것으로 판단된다.

임의적 패킷 손실과 외란입력을 고려한 네트워크 제어 시스템의 H 제어기 설계 (H Control for Networked Control Systems with Randomly Occurring Packet Losses and Disturbances)

  • 이태희;박주현;권오민;이상문
    • 전기학회논문지
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    • 제62권8호
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    • pp.1132-1137
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    • 2013
  • This paper considers the $H_{\infty}$ control problem for networked control systems(NCSs). In order to solve the problem which comes from discontinuous control signal in NCSs, an approach that discontinuous control signals treat time-varying delayed continuous signals is applied to achieve $H_{\infty}$ stability of NCSs. In addition, randomly occurring packet losses and disturbances are considered by introducing stochastic variables with Bernoulli distribution. Based on Lyapunov stability theory, a new stability condition is obtained via linear matrix inequality formulation to find the $H_{\infty}$ controller which achieves the mean square stability of NCSs. Finally, the proposed method is applied to a numerical example in order to show the effectiveness of our results.

분리 팥 단백질의 유화특성에 관한 연구 (Emulsion Properties of Small Red Bean Protein Isolates)

  • 김현정;손경희;박현경
    • 한국식품조리과학회지
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    • 제6권4호통권13호
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    • pp.9-14
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    • 1990
  • The emlsifying properties of small red bean protein isoates were evaluated through their emulsion capacity and stability of the resulting emulsions. The influence of pH, Sodium Chloride and heat treatment on the efficiency of small red bean protein isolates as emulsifying agents was studied. The surface hydrophobicity (So) of small red bean protein islates also examined. The results were obtained as follows; 1. The emusion capacity of small red bean protein isolates was high at pH 11, low at pH 3 and decreased by heat treament. With addition of NaCl, emulsion capacity decreased steadily and showed lowest value when 0.2M NaCl was added. 2. The emulsion stability at pH 4.5 and heat treatment over $60^{\circ}C$ decreased emulsion stability at pH 4.5. When NaCl was added, emulsion stability was generally increased. 3. The surface hydrophobicity of small red bean protein isolates showed the highest value at pH 3 and lowest at pH 11 and increased as the heating temperature increased When 0.2 M NaCl was added, surface hydrophobicity also increased at pH 4.5.

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Influence of Various Cyclodextrins on the Stability of Hydrocortisone 17-Butyrate in Aqueous Solution

  • Chun, In-Koo;Kim, Bo-Young
    • Archives of Pharmacal Research
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    • 제15권2호
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    • pp.176-183
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    • 1992
  • The stabilizing effects of $\alpha$-$\beta$-$\gamma$- and dimethyl-$\beta$-cyclodextrins $(\alpha$-, $\beta$-, $\gamma$- and DM-$\beta-$-CyDs) on the degradation of hydrocortisone 17-butyrate (HC-17B) in aqueous solution was investigated. Hc-17B underwent a facile hydroxide ion-catalyzed rearrangement to the less active 21-butyrate ester by the apparent first-order kinetics, and maximum stability of HC-17B was obtained at around pH 4.0. The stability of HC-17B was increased by inclusion complexation with $\alpha$-, $\gamma$- and DM-$\beta$-CyD in the pH range of 2.0-8.0 examined, whereas $\beta$-CyD accelerated the degradation of HC-17B at the pH higher than 5.0. The effects of ionic strength, solvent, temperature and CyD concentration were also investigated. Stability constants and apparent degradation rate constants of HC-17B-$\gamma$-CyD and HC-17B-DM-$\beta$-CyD complexes were determined kinetically on the basis of 1:1 complexation. The results suggested that the inclusion complexation with $\gamma$-CyD or DM-$\beta$-CyD was most useful means to enhance the stability of the steroid.

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