• Current Optics and Photonics
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• 제6권5호
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• pp.479-488
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• 2022

To account for the internal thermal effects of solid-state lasers, a method using a back propagation (BP) neural network integrated with a particle swarm optimization (PSO) algorithm is developed, which is a new wavefront distortion correction technique. In particular, by using a slab laser model, a series of fiber pumped sources are employed to form a controlled array to pump the gain medium, allowing the internal temperature field of the gain medium to be designed by altering the power of each pump source. Furthermore, the BP artificial neural network is employed to construct a nonlinear mapping relationship between the power matrix of the pump array and the thermally induced wavefront aberration. Lastly, the suppression of thermally induced wavefront distortion can be achieved by changing the power matrix of the pump array and obtaining the optimal pump light intensity distribution combined using the PSO algorithm. The minimal beam quality β can be obtained by optimally distributing the pumping light. Compared with the method of designing uniform pumping light into the gain medium, the theoretically computed single pass beam quality β value is optimized from 5.34 to 1.28. In this numerical analysis, experiments are conducted to validate the relationship between the thermally generated wavefront and certain pumping light distributions.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.282-282
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• 2003

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.271-271
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• 제47권4호
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• pp.299-305
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• 2014

In this paper, fractional factorial screening design (FFSD) and central composition design (CCD) were used to optimize the medium components for producing chitinase and gelatinase by Lysobacter capsici YS1215. Crab shell powder, nutrient broth and gelatin were proved to have significant effects on chitinase and gelatinase activity by FFSD first. An optimal medium was obtained by using a three factor CCD, which consisted of nutrient broth of $2.0gL^{-1}$, crab shell powder of $2.0gL^{-1}$ and gelatin of $1.0gL^{-1}$, respectively with the highest chitinase activity ($3.34UmL^{-1}$) and gelatinase activity ($14.15UmL^{-1}$). This value was 3.76 and 1.11 fold of the chitinase and gelatinase activity, respectively, compared to the lowest productive medium in the design matrix. In investigating potential of these enzymes partially purified from L. capsici YS1215 for biotechnological use, the crude enzymes was found to be inhibition against pathogenic fungal mycelia: Colletotrichum gleosporioides, Phytophthora capsici, and Rhizoctonia solani. In this study, we demonstrated the optimal medium for producing the chitinolytic and gelatinolytic enzymes by the strain YS1215 and the role of their enzymes that may be useful for further development of a biotechnological use and agricultural use for biological control of phytopathogenic fungi.

• ALGAE
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• 제37권2호
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• pp.175-183
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• 2022

Polar microorganisms produce physiologically active substances to adapt to harsh environments, and these substances can be used as biomedical compounds. The green microalga Micractinium variabile KSF0031, which was isolated from Antarctica, produced phytol, a natural antimicrobial agent. Furthermore, several polyunsaturated fatty acids (PUFAs), including omega-3, exhibit antioxidant properties. Here statistical methods (Plackett-Burman design and Box-Behnken design) were used to optimize the culture medium of KSF0031 to improve biomass production, and K₂HPO₄, MgSO₄·7H ₂O, and ammonium ferric citrate green (AFCg) were selected as significant components of the culture medium. Changes in the concentration of K₂HPO₄ and MgSO₄·7H ₂O as positive factors and AFCg as a negative factor affected cell growth to a remarkable degree. The biomass production in a 100 L culture using the optimized medium for 24 d at 18℃ was improved by 37.5% compared to that obtained using the original BG-11 medium. The quantities of PUFAs and phytol obtained were 13 mg g^-1 dry cell weight (DCW) and 10.98 mg g^-1 DCW, which represent improved yields of 11.70% and 48.78%, respectively. The results of this study could contribute to an improved production of phytol and fatty acids from Antarctic microalgae in the biomedical industry.

• Korean Journal of Food Science and Technology
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• 제49권6호
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• pp.610-616
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• 2017

${\gamma}$-Glutamyltranspeptidase (GGT, EC 2.3.2.2) transfers ${\gamma}$-glutamyl moiety from glutamine to amino acids or peptides and hydrolyzes glutamine to glutamate and ammonia. In order to overproduce ${\gamma}$-glutamyltranspeptidase from Bacillus amyloliquefaciens (BAGGT), the encoding gene was cloned and expressed in Bacillus subtilis. The productivity of BAGGT in Bacillus subtilis was improved by 42-fold by using a dual-promoter system that was generated by combining promoters from B. subtilis ${\alpha}$-amylase and BAGGT genes. Through optimization of medium composition by Plackett-Burman design and central composition design, BAGGT was produced at $18.3{\times}10^7U/L$ of culture in the optimized medium. Compared to previously used Luria-Bertani medium, the optimized culture medium (15 g/L molasses, 60 g/L corn steep liquor, 6 g/L yeast extract, 4 g/L NaCl, 6 g/L $K_2HPO_4$, and 2 g/L $KH_2PO_4$), resulted in a 4.3-fold increase in production of BAGGT.

• Journal of Life Science
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• 제31권8호
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• pp.761-770
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• 2021

In this study, the optimal medium composition for enhancing protease production was established by the Bacillus strain isolated from Makgeolli, a traditional fermented food, using the response surface methodology. B. amyloliquefaciens SRCM115785 was selected as the protease producer by productivity analysis and identified by 16S rRNA gene sequencing. Plackett-Burman design (PBD) was introduced to analyze the effect of each component on protease production among the 11 selected medium components. As a result, glucose, yeast extract, and beef extract were finally selected as factors for enhancing protease production. Central composite design (CCD) analysis was designed as a method to determine the optimal concentration of each component for protease production and the concentration of each medium composition for maximum protease production was predicted to glucose 6.75 g/l, yeast extract 12.42 g/l and beef extract 17.48 g/l. The suitability of the experimental model was proved using ANOVA analysis and as a result of quantitative analysis to prove this, the amount of increase was 230.47% compared to the LB medium used as a control. Through this study, the optimization of medium composition for enhancing protease production was established, and based on this, it is expected that it can be efficient use of protease as an industrial enzyme.

• Journal of Animal Science and Technology
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• 제63권3호
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• pp.603-613
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• 2021

This research improved the growth potential of Bifidobacterium animalis subsp lactis strain JNU306, a commercial medium that is appropriate for large-scale production, in yeast extract, soy peptone, glucose, L-cysteine, and ferrous sulfate. Response surface methodology (RSM) was used to optimize the components of this medium, using a central composite design and subsequent analyses. A second-order polynomial regression model, which was fitted to the data at first, significantly lacked fitness. Thus, through further analyses, the model with linear and quadratic terms plus two-way, three-way, and four-way interactions was selected as the final model. Through this model, the optimized medium composition was found as 2.8791% yeast extract, 2.8030% peptone soy, 0.6196% glucose, 0.2823% L-cysteine, and 0.0055% ferrous sulfate, w/v. This optimized medium ensured that the maximum biomass was no lower than the biomass from the commonly used blood-liver (BL) medium. The application of RSM improved the biomass production of this strain in a more cost-effective way by creating an optimum medium. This result shows that B. animalis subsp lactis JNU306 may be used as a commercial starter culture in manufacturing probiotics, including dairy products.

• KSBB Journal
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• 제14권5호
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• pp.628-632
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• 1999

Optimization of the medium and fermentation conditions for erythritol production has been studied. We have found that the optimal carbon source was glucose at the concentration of 400 g/L. The optimal temperature was 3$0^{\circ}C$ with excessive aeration. Improved erythritol productivity was achieved by reducing the yeast extract from 5 g/L to 3g/L while adding 2.7 g/L urea, 1.79g/L $K_2HPO_4, and 0.18g/L MgSO$_4$. 7$H_2O. The erythritol productivity increased from 0.747 g/L/h to 1.071 g/L/h and the yield increased from 31.4% to 45.2%. The byproduct glycerol was reduced from 96.6g/L to 45.7g/L as well. We have performed 5L fermentation with and without the pH control. The erythritol productivity with the pH control was about 30% lower than that without pH control. Excessive foaming of 5L fermentation has been observed during fermentation.

• Journal of Korea Society of Industrial Information Systems
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• 제29권3호
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• pp.41-49
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• 2024

In this paper, we validate simulation results for the design optimization of a Superconducting Fault Current Limiter (SFCL) intended for use in Medium Voltage Direct Current systems (MVDC). With the increasing integration of renewable energy and grid connections, researchers are focusing on medium-voltage systems for balancing energy in new and renewable energy networks, rather than traditional transmission or distribution networks. Specifically, for DC distribution networks dealing with fault currents that must be rapidly blocked, current-limiting systems like superconducting current limiters offer distinct advantages over the operation of DC circuit breakers. The development of such superconducting current limiters requires finite element analysis (FEM) and an extensive design process before prototype production and evaluation. To expedite this design process, the design outcomes are assimilated using a Reduced Order Model (ROM). This approach enables the verification of results akin to finite element analysis, facilitating the optimization of design simulations for production and mass production within existing engineering frameworks.