• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.379-384
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• 2010

We isolated microorganisms presenting high enzymatic activities for amylase, cellulase, protease, lipase or fibrinolysis from Korean traditional soybean sauce and paste. Then, the physiological properties and 16S rRNA sequences of isolated microorganisms were analyzed. All of the isolated 13 strains possessing high extra cellular enzyme activities have higher amylase and cellulase activities than Bacillus subtilis KACC 10114. All the selected strains have protease activities except for D2-14. Except D8-8 and K4-1, other strains have lipase activity. D2-7, D8-8 and K4-1 strains have higher fibrinolytic activities than others, while D8-2 strain has no activity. Most of the selected strains showed antibacterial activity even in gram positive and gram negative bacteria and yeast. Gene sequence analysis of 16S rRNA from isolated strains revealed that all the selected strains were member of Bacillus species.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.393-401
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• 2014

A bacterium producing antimicrobial substance was isolated from cheonggukjang. The bacterium was identified as a strain of Bacillus subtilis by 16S rDNA sequencing and designated as Bacillus subtilis HH28. The antimicrobial substance produced from Bacillus subtilis HH28 was purified by 0-80% ammonium sulfate precipitation, DEAE-sepharose FF column chromatography, and Sephacryl S-200 HR gel chromatography. The molecular weight of the purified antimicrobial substance was estimated to be approximately 3,500 Da using Tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis and direct detection analysis. Antimicrobial substance from B. subtilis HH28 not only inhibited B. cereus, but also Listeria monocytogenes and Vibrio parahaemolyticus. The purified antimicrobial substance was stable at $40-80^{\circ}C$, and between pH 2 and 8. Antimicrobial activity of the purified substance was completely destroyed by treatment of protease, proteinase K, and pronase E, indicating that it is proteinaceous.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.116-124
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• 2015

The objective of this study is to evaluate the effects of the replacement levels of grinded fly-ash on the repaired mortar based on a polymer. The main parameters are the curing temperature and replacement levels of grinded fly-ash. The curing temperature and the replacement levels of grinded fly-ash are varied at $40^{\circ}C$, $20^{\circ}C$ and $5^{\circ}C$, and between 0% and 35% of the total binder by weight, respectively. The flow in fresh mortar and compressive strengths according to ages, the relationship of stress-strain, elastic modulus and modulus rupture in hardened mortar, as well as scanning the electron microscopy and the X-ray diffraction of mortar, were measured, respectively. The test results showed that the flow, elastic modulus and modulus rupture are great in mortar specimens with 20~30% of the replacement levels of grinded fly-ash. In addition, compressive strengths according to ages were affected by the replacement levels of grinded fly-ash and the curing temperature indicated that the strength development ratio of mortar with 20% of the replacement levels of grinded fly-ash was greater than others. In the prediction of the compressive strength specified by the ACI 209 code, the strength development at an early and late age can be generalized by the functions of the replacement levels of grinded fly-ash and the curing temperature. In the analysis of scanning the electron microscopy and the X-ray diffraction, the number and intensity of peaks increased and the form of CSH gels on the surface of the particle of grinded fly-ash was observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.466-469
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• 2011

The purpose of this study was to obtain the fatty acid composition and the antibacterial activity against pathogen of acne in various parts including seed, flesh and fruit from ripened black raspberry. In fatty acid analysis of lyophilized black raspberry, total fat of dried seed (11.047%) was much higher than in other parts. Moreover, linoleic acid (5.577%) and linolenic acid (2.317%) identified as the major fatty acids in the seed. By contrast, highest fatty acid of dried flesh was palmitic acid (0.323%) but it was remarkably low level compared with fatty acid composition of dried seed. Total polyphenol content in seed extract and flesh extract were 123.64 mg/g and 55.43 mg/g, respectively. DPPH radical scavenging ability of seed extract was higher than flesh and fruit extract. In antibacterial activity experiment against strains related acne such as Propionibacterium acne and Staphylococcus epidermidis, antibacterial activity of flesh extract was stronger than seed extract. However, seed extract showed antibacterial activity of 76.96~89.08% against each strain compared to activity of flesh extract. Based on these results, we concluded that seed of black raspberry can be useful in related field.

• Journal of the Korean Geotechnical Society
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• v.21 no.8
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• pp.107-116
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• 2005

Generally, when the stability of the geosynthetic reinforced soil slopes is analyzed, the required tensile forces of each reinforcement layers are calculated from total reinforcement forces which are necessary to retain the equilibrium state of slip mass in which the slip surfaces are assumed to be a linear or bilinear. It is assumed that the reinforcement forces are increased or constant with depth. However, according to the instrumented field data and laboratory model test results, the maximum tensile strain of reinforcement in a reinforced soil slope is developed in a certain elevation, not a bottom of the slope. In the concept of reinforced soil, postulated failure surfaces are the traces of the position in which the reinforcement tensile forces are maximum in the layer, and the reinforcement tensile forces are related to the stress state on the postulated failure surface. Therefore, in this study, based on the distribution of normal stress on the slip surface, a new method for the evaluation of required tensile forces is suggested and a number of the instrumented field data are analyzed by newly suggested method. As a result, it is shown that the newly suggested method produces relatively accurate reinforcement tension forces.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.43-50
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• 2016

A reinforcement is required to ensure the structural safety in case of railway embankment excavation under railway load. A large diameter soil nailing with concrete wall is applied as the reinforcement method instead of the conventional soil nailing system. In this study, a series of 3 dimensional numerical analyses are performed to investigate the optimum reinforcement considering 15 different conditions based on the length, lateral spacing, diameter, and inclination of the reinforcement. The interface between soil nail and perimetric grout is considered by means of cohesion, stiffness and perimeter of the grout. 0.3 m of reinforcement diameter is assessed as the most appropriate based on the economical viewpoint though ground displacement decreases with the increase of diameter, however the difference of displacement is negligible between 0.4 m and 0.3 m of diameter. Surface settlement, lateral displacement of wall, and stress of reinforcement are calculated and economic viewpoint to reinforce embankment considered. Consequently, the optimum reinforcement conditions considering those factors are evaluated as 3 m in length, 0.3 m in diameter, 1.5 m in lateral spacing, and 10 degree of inclination angle in the case of 3 m of excavation depth. Additionally, inclined potential failure surface occurs with approximately 60 degrees from the end of nails and the surface settlement and wall lateral displacement are restrained successfully by the large diameter soil nailing, based on the result of shear strain rate.

• Computational Structural Engineering
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• v.10 no.4
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• pp.165-175
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• 1997

In this paper, the stress, buckling and vibration analyses have been performed for several case with the spot weld stiffened rear side frame, the unstiffened rear side frame and the dual thickness laser weld rear side frame. For stress and vibration analyses, the clamped boundary condition with spring supports are used. But for the buckling analyses, the both ends simply supported boundary conditions are used. For the nummerical analyses, ANSYS 5.0 code is adopted. Maximum stress of the spot weld stiffened rear side frame occurs in the main frame and is 80.9 MPa. Maximum strain is 501 .mu.. The maximum stress of the dual thickness laser weld rear side frame of 1.8mm thickness structure is equal with the stress of spot weld stiffened frame. The weight of dual thickness laser weld frame can be reduced about 17.2%. For the stiffened spot weld rear side frame with both ends simply supported boundary conditon, the bucking load is 52.54 kN. When the thickness of the dual thickness laser weld rear side frame become 1.9mm thickness structure, the buckling load of the stiffenerd rear side frame is equal to that of dual thickness laser weld frame. The reduction of the structure weight is about 5%. The fundamental natural frequency of the stiffened spot weld rear side frame for bending mode is 163.6 Hz and that of the dual thickness laser weld rear side frame is 179.8 Hz.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.1-7
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• 2017

In general, the large loads which are applied from explosion, impact, earthquake and wind at a short time caused the materials of structures to large deformations, rotations and strains locally. If such phenomena will be analyzed, hydrocodes which can be considered fluid-structure interaction under computational continuum mechanics are inevitably needed. Also, the explosion mechanism is so complicated, it is reasonable that the behaviors of structure are predicted through explosion analyses and experiment at the same time. But, unfortunately, it is true that explosion experiments are limited to huge cost, large experiment facilities and safety problems. Therefore, in this study, it is shown that the results of explosion analyses using the AUTODYN are agreed with those of existing explosion experiments for reinforced concrete slabs within reasonable error limits. And the explosion damage of the same reinforced concrete slab are assessed for quite different reinforcement arrangement spacings, concrete cover depths, and vertical reinforcements. From the explosion analyses, it is known that the more the ratio of slab thickness to reinforcement arrangement spacing is increased, and small-diameter reinforcements are used than large-diameter reinforcements on the same reinforcement ratio, and vertical reinforcements are used, the more the anti-knock capacities are improved.

• Steel and Composite Structures
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• v.13 no.3
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• pp.239-258
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• 2012

In this paper, experimental investigations on high strength steel (HSS) stud connected steel-concrete composite (SCC) girders to understand the effect of shear connector density on their flexural behaviour is presented. SCC girder specimens were designed for three different shear capacities (100%, 85%, and 70%), by varying the number of stud connectors in the shear span. Three SCC girder specimens were tested under monotonic/quasi-static loading, while three similar girder specimens were subjected to non-reversal cyclic loading under simply supported end conditions. Details of casting the specimens, experimental set-up, and method of testing, instrumentation for the measurement of deflection, interface-slip and strain are discussed. It is found that SCC girder specimen designed for full shear capacity exhibits interface slip for loads beyond 25% of the ultimate load capacity. Specimens with lesser degree of shear connection show lower values of load at initiation of slip. Very good ductility is exhibited by all the HSS stud connected SCC girder specimens. It is observed that the ultimate moment of resistance as well as ductility gets reduced for HSS stud connected SCC girder with reduction in stud shear connector density. Efficiency factor indicating the effectiveness of high strength stud connectors in resisting interface forces is estimated to be 0.8 from the analysis. Failure mode is primarily flexure with fracturing of stud connectors and characterised by flexural cracking and crushing of concrete at top in the pure bending region. Local buckling in the top flange of steel beam was also observed at the loads near to failure, which is influenced by spacing of studs and top flange thickness of rolled steel section. One of the recommendations is that the ultimate load capacity can be limited to 1.5 times the plastic moment capacity of the section such that the post peak load reduction is kept within limits. Load-deflection behaviour for monotonic tests compared well with the envelope of load-deflection curves for cyclic tests. It is concluded from the experimental investigations that use of HSS studs will reduce their numbers for given loading, which is advantageous in case of long spans. Buckling of top flange of rolled section is observed at failure stage. Provision of lips in the top flange is suggested to avoid this buckling. This is possible in case of longer spans, where normally built-up sections are used.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.99-110
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• 2012

Comparison on the genomic structure and phylogenetic relationship of the Hsp88 genes from P. tenuipes Jochoen-1, P. tenuipes, C. militaris and C. pruinosa was described. The Hsp88 genes from the three entomopathogenic strains, P. tenuipes Jocheon-1(strain), P. tenuipes(original species), and C. militaris contain the identical genomic structure, namely 5 introns and 6 exons with the length of 13, 62, 32, 1,438, 306, 288 nucleotides encoding 713 amino acid residues, whereas in case of C. pruinosa, it contains 4 introns and 5 exons with the length of 13, 62, 32, 1,744, 288 nucleotides encoding 713 amino acid residues. The genomic DNA length of the Hsp88 genes from P. tenuipes Jocheon-1 and P. tenuipes are both 2,600 nucleotides long in size. The Hsp88 genes from C. militaris and C. pruinosa are 2,582, 2,576 nucleotides long in size, respectively. Hsp88 genes of the P. tenuipes Jochoen-1, P. tenuipes, C. militaris and C. pruinosa also contain the conserved ATP-binding domain. Phylogenetic analysis of the Hsp genes of the four strains tested in this study showed that the fungal Hsp88 is divided into two separate clades, ascomycetes and deutromycete. Within the ascomycetes fungal clade, the P. tenuipes Jochoen-1 and P. tenuipes formed a subgroup, on the other hand, C. militaris and C. pruinosa formed another subgroup. Pair-wise comparison of P. tenuipes Jocheon-1 Hsp88 with those of P. tenuipes, C. militaris and C. pruinosa Hsp88s revealed significant identity in deduced amino acid sequence among these strains. The P. tenuipes Jocheon-1 Hsp88 showed 99% identity with the P. tenuipes, 97% identity with the C. militaris, and 98% identity with the C. pruinosa.