• Korean Journal of Microbiology
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• v.40 no.2
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• pp.139-146
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• 2004

A bacterium producing alkaline cellulase was isolated from soil, leaf mold and compost, and was identified as alkalophilic Bacillus sp. HSH-810 by morphological, cultural and biochemical determination. The optimum cul-ture condition of Bacillus sp. HSH-810 for the growth and alkaline cellulase production was $30^{\circ}C$ and pH 10.0. The maximum alkaline cellulase production was obtained when 1.0%(w/v) CMC, 0.5%(w/v) peptone, 0.02%(w/v) $CaCl_2$ and 0.02(w/v) $CoCl_2$ were used as carbon source, nitrogen source and mineral source, respectively. The optimum pH and temperature of the enzyme activity were pH 10.5 and $50^{\circ}C$, respectively. This enzyme was fairly stable in the pH range of 6.0-13.0 and at $50^{\circ}C$. For the effect of surfactants, the activity of alkaline cellulase was stable in the presence of sodium-$\alpha$-olefin sulfonate (AOS), sodium dodecyl sulfonate (SDS), Tween 20 and Tween 80, but inhibited by the presence of 0.1 linear alkyl-benzene sulfonate (LAS) sig-nificantly.

• The Journal of the Acoustical Society of Korea
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• v.33 no.2
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• pp.111-117
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• 2014

In this paper, the structure-borne noise reduction on electrical equipment is discussed by the experimental analysis. The water cooling system in electrical equipment is the only noise source, so the mock-up was made to measure noise characteristics. Effects of power supply, stiffness, isolation of noise source and natural frequency determined by resilient mounts are investigated using the mock-up. The console prototype was made referring to noise reduction technique by the mock-up. The structure-borne noise level of a console prototype was measured and some experiments to reduce the noise was undertaken. The $1^{st}$ and $4^{th}$ harmonics of operating frequency of cooling fans causes highest structure-borne noise levels. The control of operating speeds of several DC cooling fan groups was tried. Also types and installation layouts of resilient mounts were investigated. To reduce structure-borne noise, followings can be applied: increase of stiffness, isolation of source, decrease of natural frequency of mount, combination of operating speed of fans, selection of mounts, and so on.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.5
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• pp.253-260
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• 2014

European Space Agency has recognized Integrated Modular Avionics and ARINC specification 653 as avionics computer system for space application. Integrated Modular Avionics specification reduces the space by integrating a system composed of many electronic devices into a computer. recent researches have been studying how to apply the ARINC 653 into an open source operating system, such as Linux. These studies have concentrated on partition scheduling for time separation. However, requirements to guarantee spatial separation should be further analyzed to ensure deterministic execution time. Therefore, memory management is needed to verify spatial isolation on Linux systems. This research proposes a new method to accomplish spatial isolation for the ARINC 653 specification in Linux. We have added new data structures and system calls to handle functionalities for spatial separation. They are used during the partition startup process. The proposed method was evaluated on the LEON4 processor, which is the next generation microprocessor to be used in the future space missions. All implementations confirm that spatial isolation of the ARINC 653 specification was accomplished.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1684-1685
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• 2011

This paper presents a theoretical and numerical analysis for thermal isolation of silicon micro-structures, especially for a large size with poor thermal conductivity, as well as straightforward solution for such an issue. Additional metal patterns underneath the silicon structures effectively reduces the thermal isolation. Heat transfer mechanism is analyzed using an equivalent circuit of thermal network including plasma, a heat source, heat capacitors, and thermal resistances. The FEM simulation was carried out to investigate the temperature change of silicon micro-structures according to process time. The temperature of silicon micro-structures with 2 ${\mu}m$ thick chrome layer at a steady state is $86^{\circ}C$, an approximately 40% decrease from the silicon microstructure without thin metal ($122^{\circ}C$)

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.36-42
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• 1995

Actinomycetes occur in a wide range of environments and many more actinomycetes remain to be detected in the natural environment. In isolation stages, selection of the environment as a source of useful isolates is important. Two hundred and eighteen strains were isolated on Bennet's agar and 346 strains were on humic acid-vitamin agar from five each paddy field, field, forest, grass land, riverside soil samples. These isolates were identified to the genus level based on morphological and physiological characteristics. Among them, 386 strains were Streptomyces, 49 strain were Nocardia, 35 strains were Microbispora and Micromonospora each, 15 strains were Nocardiopsis, 13 strains were Actinomadura, 10 strains were Streptosporangium, and the others were isolated rarely. According to soil type, Nocardia, Micromonospora, Microbispora and Streptosporangium were dominant in paddy field, Microbispora Nocardia, Nocardioides and Micromonospora were dominant in field, Nocardia, Micromonospora, Microbispora and Actinomadura were dominant in grass land, Nocardia, Micromonospora and Microbispora were dominant in forest, Nocardia, Microbispora and Micromonospora were dominant in riverside. Generally, Nocardia, Micromonospora, Microbispora and Actinomadura were isolated in all kinds of soils, Streptosporangium were paddy field, Dactylosporangium were forest, Nocardiopsis were field, forest and riverside.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.409-417
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• 2018

Biologically produced 2,3-butanediol (2,3-BDO) has diverse industrial applications. In this study, schematic isolation and screening procedures were designed to obtain generally regarded as safe (GRAS) and efficient 2,3-BDO producers. Over 4,000 candidate strains were isolated by pretreatment and enrichment, and the isolated Bacillus strains were further screened by morphological, biochemical, and genomic analyses. The screened strains were then used to test the utilization of the most common carbon (glucose, xylose, fructose, sucrose) and nitrogen (yeast extract, corn steep liquor) sources for the economical production of 2,3-BDO. Two-stage fed-batch fermentation was finally carried out to enhance 2,3-BDO production. In consequence, a newly isolated Bacillus licheniformis GSC3102 strain produced 92.0 g/l of total 2,3-BDO with an overall productivity and yield of 1.40 g/l/h and 0.423 g/g glucose, respectively, using a cheap and abundant nitrogen source. These results strongly suggest that B. licheniformis, which is found widely in nature, can be used as a host strain for the industrial fermentative production of 2,3-BDO.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.618-623
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• 2001

In a practical vibration isolation system, vibration is transmitted from the source to the receiver through several paths such as more than one inter-connected point and multi-degree of freedom at each connection point. Therefore, the major path investigation for vibration transmission among them is often required in a point of view of isolation. For the path analysis of multi-dimensional vibration isolation system, it is useful to employ the concept of vibration power in high frequency range where radiation of noise from the receiver structure is concerned. The idea is simple to understand and formulate but rather complicated to apply in practice. For an accurate estimation of power flow especially over a high frequency range, it is well known in theory that rotational motions should be taken into consideration together with translational motions at inter-connected points. In reality, however, power transmissions related to rotational terms are often neglected mainly due to difficulties in the instrumentation. In this paper, necessary formula and measurable mechanical quantities for vibration power analysis will be reviewed and experimental results with rotational terms included for compressor system in a commercial air conditioner will be shown.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1590-1597
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• 1993

Power conversion system generally requires bidirectional converter. A storage energy of reactor is suppressed by regeneration of surplus electic energy in converter to power source. When an electric isolation in the power conversion system is required. the most suitable position for the isolation is the DC-Link part. A transformer in the DC part is minimized because of high repetition frequency. This paper proposes that power conversion system becomes bidirectional DC-DC converter with electric isolation by intergrated voltage control method. It is intergrated voltage control that makes system construciton simple, has control errow little quantity ans gets output response Quick. And the power-switches which should be operated is selected automatically without a detection of the current-direction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.10
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• pp.902-908
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• 2013

The input torque ripple induced by combustion engines is a significant source of NVH(noise, vibration and harshness) problem in automotive transmissions. Because this torque fluctuation is primarily transmitted to the input shaft of automotive powertrains(e.g., automatic transmissions) when the lock-up clutches are closed, a torsional damper with helical springs is generally inserted between engine and transmissions to isolate the input vibratory energy, which is essential for the passenger comfort. The torsional vibration isolator exhibits frequency ranges in which there is low vibration transmissibility. However, the isolation performance is currently evaluated through the static torsional spring characteristics. In this study, the transmissibility of torsional spring dampers, essential dynamic performance index for vibration isolator, is first experimentally evaluated.

• KSBB Journal
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• v.13 no.5
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• pp.518-523
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• 1998

A large quantity of ethylene glycol(EG) is remained in the effluent after pretreating polyester weight-loss wastewater physicochemically in the fist stage and must be treated biologically in the second stage. Therefore, an excellent EG-utilizing bacteria strain was isolated from the natural system and the optimal culture conditions of the strain were investigated. The optimal culture conditions of temperature, pH, and nitrogen source were found to be 35$^{\circ}C$, 7.5 and ammonium chloride, respectively, when CODCr removal efficiency was more than 90%. The growth of stains and EG removal efficiency was slightly improved by adding elements such as niacin and biotin. With increasing inoculation size in a batch culture, the removal efficiency of EG was conspicuously increased. Growth rate was inhibited when the initial concentration of EG was more then 30g/L. The strain was identified as Pseudomonas sp. based on morphological and biological characteristics and named as Pseudomonas sp. EG1.