• Journal of Korean Association for Spatial Structures
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• v.17 no.4
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• pp.159-165
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• 2017

In this paper, uniaxial tensile tests of ETFE films with three kinds of thicknesses(100, 200, $250{\mu}m$) and two kinds of directions(machine direction & transverse direction) are performed and the tensile strength, the tensile strain at break and the Young's modulus of ETFE films are compared for two kinds of specimen types(2 & 5). It could be figured out that there are no significant difference between tensile strengths of two specimen types but the tensile strain at break and the Young's modulus of ETFE films are affected by the specimen types. And it is concluded that the uniaxial tensile test of specimen type 2 are more reliable than that of specimen type 5.

• Transactions of Materials Processing
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• v.25 no.5
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• pp.319-324
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• 2016

Recently, the roll forming process is one of the most widely used processes for manufacturing automotive part. In this study, flower patterns of roll forming process were designed to manufacture an ultra high strength bumper beam using the finite element analysis. Three types of flower patterns such as the basic type, the rotation type and the split type were designed based on the constant arc length forming method using the design software, UBECO Profil. Finite element analysis was performed to evaluate the suitability of designed flower patterns in terms of the longitudinal strain and the bow defect. The analytical results show that the split type represents more uniform longitudinal strain distributions and a good dimensional accuracy than other types of flower patterns.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.777-780
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• 1995

A strain US50-3 producing water-soluble red pigment was isolated from the pond separating oil from water near the oil storage tanks. The strain US50-3 was identified as a strain of Serratia marcescens considering its morphological and physiological characteristics, and DNA G+C contents. It showed a little difference comparing to the Type strain and was considered to be another biotype strain.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.416-420
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• 2002

This Paper describes a matched-filter type strain sensor system using optical fiber Bragg grating (FBG) sensor. Matched-filter type uses another wavelength-matched FBG filter to track wavelength shift in the FBG sensor. Filter FBG is attached on a fiber stretcher and stretched by PZT actuator. To overcome the nonlinearity and hysteresis of the PZT actuator that degrades system accuracy, a string resonator which can measure an absolute strain is employed. And the effect of vibration modes on string resonator is investigated particularly regarding its sensitivity and stability.

• Korean Journal of Microbiology
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• v.29 no.3
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• pp.160-166
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• 1991

The regulatory mechanism of tubercidin biosynthesis in Streptomyces tubercidicus was studied. In a wild type strain, addition of adenine and histidine into the medium decreased the tubercidin production by 60-65% and 40%, respectively. The effects of adenine and histidine were alleviated by the addition of inosine monophosphate and 5-aminoimidazole-4-carboxamide ribotide. The production of tubercidin in S. tubercidicus K115 strain ($ade^{-}$ ) was nearly shut off by histidine. In contrast with K115 strain, adenine inhibited the tubercidin biosynthesis in S. tubercidicus K412 strain ($his^{-}$. In S. tubercidicus F667 strain ($ade^{-}$ , $his^{-}$ ), tubercidin production was increased by adenine and histidine. From the effects of adenine and histidine on tubercidin biosynthesis in S. tubercidicus wild type and mutant strains, it became known that feedback control by adenine and histidine of biosynthetic pathwat for purine ribonucleotide and histidine are involved in the regulation of tubercidin biosynthesis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.750-757
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• 2003

In order to determine creep stress intensity limit of high-temperature components, the usefulness of the creep work and time equation, defined as W$\_$c/t$\^$p/ = B(where W$\_$c/ = $\sigma$$\varepsilon$ is the total creep work done during creep, and p and B are constants), was investigated using the experimental data. For this Purpose, the creep tests for generating 1.0% strain for commercial type i16 stainless steel were conducted with different stresses; 160 MPa, 150 MPa, 145 MPa, 140 MPa and 135 MPa at 593$^{\circ}C$. The plots of log W$\_$c/ - log t showed a good linear relation up to 10$\^$5/ hr, and the results of the creep work-time relation for p, B and stress intensity values showed good agreement to those of isochronous stress-strain curves (ISSC) presented in ASME BPV NH. The relation can be simply obtained with only several short-term 1% strain data without ISSC which can be obtained by long-term creep data. Particularly, this relation is useful in estimating stress intensity limit for new and emerging class of high-temperature creeping materials.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.214-220
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• 2019

The calibration method of the initial value error obtained in the weight measurement through anchor bolt type strain gauge sensor is proposed. The strain gauge sensor is developed for preventing the overturning of forklift, which is the most frequent type of safety-accident in industry. It was confirmed that the initial value error is caused from the physical and mechanical error of anchor bolt, and the environmental problem. Since the elimination of these causes falls outside the realm of this research, we find out the calibrated values based on all the causes, and we adjust the initial values of analog-to-digital convertor (ADC) module consisted of strain gauge sensor block using the calibrated values. We use the linear interpolation method for our calibration. We confirm that four sensor modules have the different under 5% between the real weight and the measured value in the experiment applied with the calibration of initial values. The low correlation between the real weights and ADC values is also improved through the proposed calibration.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.8-24
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• 1984

In this study, investigated the effects of four strains belonging to Aspergillus oryzae on the quality of Kochujang. In the Koji and Kochujang making, investigated the difference of enzyme production of each strain, the change of each component and color during the aging, and tested the sensory taste. The results obtained were as follows; 1. Protease activity (acid, neutral) in wheat flour Koji was high in the case of Aspergillus $oryzae-S_1$ and Aspergillus oryzae - M of short stalked type. The strain Aspergillus $oryzae-S_1$ showed maximum activity after two days of Koji making, while the strain Aspergillus oryzae - M showed low activity till two days, but showed maximum activity after three days-four days of Koji making. 2. In $\alpha$-amylase activity, strain Aspergillus $oryzae-S_1$, Aspergillus $oryzae-S_2$ and Aspergillus oryzae - M showed high activity after two days of Koji making. Aspergillus oryzae-NB strain showed slower ${\alpha}$ - amylase activity than that strains. 3. In glucoamylase activity, all strain tested showed high activity after three days of Koji making, but st rain Aspergillus oryzae - NB showed slower activity than ot - hers. 4. In protease activity (acid, neutral) during the aging of Kochujang, strain Aspergillus $oryzae-S_1$ and Aspergillus oryzae - M of short stalked type showed higher activity than that of long stalked type. 5. Amino type nitrogen contents during the aging of Kochujang was very higher in the case of strains Aspergillus $oryzae-S_1$ and Aspergillus oryzae - M of short stalked type than other strains, and each contents was 315mg% and 337mg% after aged for ninty days. 6. The results that analysed free sugar of Kochujang aged for ninty days with HPLC were; glucose 5.84~7.13%, fructose 4.13~5.00%, rhamnose 0.91~1.04%, maltose 0.72~0.92% and presence of xylose was recognized. 7. The results that analysed alcohols of Kochujang aged for ninty days with gas chromatography were; ethanol 1.51~1.78%, n-propyl alcohol 1.13~1.20mg%, iso-amyl alcohol 3.5~4.4mg%. 8. In the sensory test of Kochujang aged for sixty days and for ninty days, the case of strains Aspergillus oryzae-M and Aspergillus $oryzae-S_1$ of short stalked type showed good taste, while the case of strains Aspergillus $oryzae-S_2$ and Aspergillus oryzae-NB of long stalked type showed good flavor and color.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.539-544
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• 2008

A mutant of Arthrospira platensis PCC 9108, strain M9108, obtained by mutagenesis with UV treatment, was able to mixotrophically grow in an SOT medium containing 40 g of glucose/l. The biomass and specific growth rate of strain M9108 (4.10 g/l and 0.70/d) were 1.9-fold and 1.4-fold higher, respectively, than those of the wild type (2.21 g/l and 0.58/d) under mixotrophic culture condition. In addition, when compared with the wild type, the content of ${\gamma}$-linolenic acid (GLA) in the mutant was increased when glucose concentration was increased. Compared with the wild type, the GLA content of the mutant was 2-fold higher in autotrophic culture and about 3-fold higher in mixotrophic culture. Thus, the mutant appears to possess more efficient facility to assimilate and metabolize glucose and to produce more GLA than its wild-type strain.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.189-192
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• 2000

The objective of this study was to investigate the effect of high content of light-absorbing pigments on overall photosynthetic efficiency in high density microalgal cultures. The light harvesting complex II (LHC II) regulating gene of Rhodobacter sphaeroides, photosynthetic purple bacterium, was removed to construct a mutant strain that had less pigment content. The mutant and wild type strains were cultured under various light intensity by adjusting the distance from the light source. The productivity of the mutant strain was higher at high light intensity (over 118 ${\mu}E/m^2/s$) compared with one of the wild type , and was lower at low light intensity (34 ${\mu}E/m^2/s$). Especially, the concentration of LHC II mutant strain was 56% higher at 118 ${\mu}E/m^2/s$. The reduction of per cell pigment contents in the mutant strain lessened the degree of the mutual shading and thus enhanced the overall photosynthetic efficiency.