• Title/Summary/Keyword: L/H

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LITTLE HANKEL OPERATORS ON WEIGHTED BLOCH SPACES IN Cn

  • Choi, Ki-Seong
    • Communications of the Korean Mathematical Society
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    • v.18 no.3
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    • pp.469-479
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    • 2003
  • Let B be the open unit ball in $C^{n}$ and ${\mu}_{q}$(q > -1) the Lebesgue measure such that ${\mu}_{q}$(B) = 1. Let ${L_{a,q}}^2$ be the subspace of ${L^2(B,D{\mu}_q)$ consisting of analytic functions, and let $\overline{{L_{a,q}}^2}$ be the subspace of ${L^2(B,D{\mu}_q)$) consisting of conjugate analytic functions. Let $\bar{P}$ be the orthogonal projection from ${L^2(B,D{\mu}_q)$ into $\overline{{L_{a,q}}^2}$. The little Hankel operator ${h_{\varphi}}^{q}\;:\;{L_{a,q}}^2\;{\rightarrow}\;{\overline}{{L_{a,q}}^2}$ is defined by ${h_{\varphi}}^{q}(\cdot)\;=\;{\bar{P}}({\varphi}{\cdot})$. In this paper, we will find the necessary and sufficient condition that the little Hankel operator ${h_{\varphi}}^{q}$ is bounded(or compact).

Enhanced Production of L-Aspartate ${\beta}-Decarboxylase$ by Nitrogen Source in Pseudomonas dacunhae

  • Kim, Dong-Chung;Lee, Sung-Dong;In, Man-Jin
    • Journal of Applied Biological Chemistry
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    • v.49 no.3
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    • pp.106-109
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    • 2006
  • Improvement of L-asparate ${\beta}-decarboxylase$ production from Pseudomonas dacunhae ATCC 21192 was attempted by optimizing fermentation conditions. Optimum carbon and nitrogen sources for cell growth and enzyme production were determined. L-Glutamate (2%) was the most suitable carbon source, and D-glucose, D-glycerol and fumarate repressed enzyme production. Yeast extract (2%) was the most effective as nitrogen source. A slight change of pH to 6.5 from medium pH resulted in a meaningful increase in the production of enzyme. The production of the enzyme was highly improved by using 2% yeast extract and 2% L-glutamate in culture media. Maximum L-asparate ${\beta}-decarboxylase$ activity reached up to over 24 U/mL-broth by 15 h flask fermentation.

ON CHARACTERIZATIONS OF THE POWER DISTRIBUTION VIA THE IDENTICAL HAZARD RATE OF LOWER RECORD VALUES

  • Lee, Min-Young
    • Journal of the Chungcheong Mathematical Society
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    • v.30 no.3
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    • pp.337-340
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    • 2017
  • In this article, we present characterizations of the power distribution via the identical hazard rate of lower record values that $X_n$ has the power distribution if and only if for some fixed n, $n{\geq}1$, the hazard rate $h_W$ of $W=X_{L(n+1)}/X_{L(n)}$ is the same as the hazard rate h of $X_n$ or the hazard rate $h_V$ of $V=X_{L(n+2)}/X_{L(n+1)}$.

Simultaneous Saccharification and Extractive Fermentation for Lactic Acid Production (동시당화 및 추출발효에 의한 Lactic Acid 생산)

  • 공창범;우창호;최실호;윤현희
    • KSBB Journal
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    • v.14 no.2
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    • pp.212-219
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    • 1999
  • lactic acid production from cellulose by simultaneous saccharification and fermentation(SSF) was studied. The SSF using cellulase enzyme Cytolase CL and Lactobacillus delbrueckii was strongly inhibited by the end product(lactic acid). An ion-exchange resin(RA-400) was used for in-situ product removal during SSF. The sorption capacity of the resin was 200mg/g-resin. The simple SSF and the extractive SSF resulted in lactic acid concentrations of 30.4g/L and 32.0g/L, respectively, at the initial substrate concentration of 50g/L. A model was developed to simulate the extractive SSF. The lactic acid conversion for the initial substrate of 100g/L was estimated to be improved from 60% to 09% by in-situ product removal. The experimentally determined kinectic parameters were pH dependent, and fitted as empirical expressions to establish their values at different pH's. Lactic acid productivity was predicted to be maximum at pH 4.5-5.0.

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Effect of pH on Growth and Ethanol Production of Clostridium ljungdahlii (Clostridium ljungdahlii 성장 및 에탄올 생산에 pH가 미치는 영향)

  • Park, So Jung;Hong, Sung-Gu;Kang, Kwon-Kyoo;Kim, Young-Kee
    • Applied Chemistry for Engineering
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    • v.22 no.5
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    • pp.562-565
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    • 2011
  • In this study, we developed a bioprocess using Clostridium ljungdahlii as a biological catalyst to produce bio-ethanol, and the effect of pH on microbial growth and ethanol production was investigated. From the results of fermentation at various initial pH condition without pH control, pH of fermentation broth decreased to 4.5 within 24 h due to accumulation of by-product acetic acid and both microbial growth and ethanol production were stopped. The experimental result of initial pH 8 showed the highest microbial growth and ethanol production (0.53 g/L), since the pH drop was relatively slow. From the experiment of pH 7 maintained fermentation using pH controllable bioreactor, the maximum cell dry weight of 1.65 g/L and the maximum ethanol concentration of 1.43 g/L were obtained within 24 h. In conclusion, the C. ljungdahlii growth was enhanced by pH maintenance of neutral range, and the ethanol production was also enhanced based on the growth-associated ethanol production characteristics of C. ljungdahlii.