• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.1-11
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• 2021

Piping systems comprising pumps and valves are essential in the power plant, oil, and defense industry. Their purpose includes a stable supply of the working fluid or ensuring the target system's safe operation. However, piping system accidents due to leakage of toxic substances, explosions, and natural disasters are prevalent In addition, with the limited maintenance personnel, it becomes difficult to detect, isolate, and reconfigure the damage of the piping system and recover the unaffected area. An autonomous recovery piping system can play a vital role under such circumstances. The autonomous recovery algorithms for the piping system can be divided into low-pressure control algorithms, hydraulic resistance control algorithms, and flow inventory control algorithms. All three methods include autonomous opening/closing logic to isolate damaged areas and recovery the unaffected area of piping systems. However, because each algorithm has its strength and weakness, appropriate application considering the overall design, vital components, and operating conditions is crucial. In this regard, preliminary research on algorithm's working principle, its design procedures, and expected damage scenarios should be accomplished. This study examines the characteristics of algorithms, the design procedure, and working logic. Advantages and disadvantages are also analyzed through simulation results for a simplified piping system.

• Earthquakes and Structures
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• v.21 no.5
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• pp.461-475
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• 2021

Strategic structures are a potential target of the growing terrorist attacks, so their performance under explosion hazard has been paid attention by researchers in the last years. In this regard, the aim of this study is to evaluate the blast-resistance performance of lead-rubber bearing (LRB) base isolation system based on a probabilistic framework while uncertainties related to the charge weight and standoff distance have been taken into account. A sensitivity analysis is first performed to show the effect of explosion uncertainty on the response of base-isolated buildings. The blast fragility curve is then developed for three base-isolated steel moment-resisting buildings with different heights of 4, 8 and 12 stories. The results of sensitivity analysis show that although LRB has the capability of reducing the peak response of buildings under explosion hazard, this control system may lead to increase in the peak response of buildings under some explosion scenarios. This shows the high importance of probabilistic-based assessment of isolated structures under explosion hazard. The blast fragility analysis shows effective performance of LRB in mitigating the probability of failure of buildings. Therefore, LRB can be introduced as effective control system for the protection of buildings from explosion hazard regarding uncertainty effect.

• Journal of Life Science
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• v.10 no.3
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• pp.262-272
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• 2000

As a part of investigation for basic epidemiology of diarrheogenic disease, we attempted isolation of Escherichia coli from patients with diarrhea. Seven hundred and twenty-one strains of E. coli were isolated from 1,239 patients with diarrhea. Seasonal distribution of patient with diarrhea was shown the most high at August (18.2%). Age group distribution of patient was shown the most high at children (54.6%, 2 to 10 years old). The serotypes of 721 E. coli isolates were in order of serotype O44 (16.8%), O153 (8.6%), O1 (7.5%), O166(5.7%), O8 and O86a (4.7%), and O125 (4.6%). The supernates cultured 36 strains among 721 E. coli isolates were indicated cytotoxicity against monolayered Vero cells. All of the isolates were susceptible to amikacin. The isolates were resistant in order of novobiocin (99.0%), moxalactam (97.1%), carbenicillin (96.1%), tetracycline (90.4%), ampicillin (85.9%), gentamicin (84.0%), streptomycin (78.4%), cephalothin (46.6%) and polymyxin B (4.2%). In the antibiotic resistant patterns, 125 kinds of multiple resistance patterns of E. coli isolates were detected. The highest resistant pattern was ampicillin-carbenicillin-chloramphenicol-cephalothin-erythro-mycin- gentamicin-moxalactam-novobiocin-penicillin G-streptomycin-tobramycin-tetracycline-tri methoprim type (24.3%).

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.1-6
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• 2014

Flip chip bonded LED packages possess lower thermal resistance than wire bonded LED packages because of short thermal path. In this study, thermal and bonding properties of flip chip bonded high brightness LED were evaluated for Au-Sn thermo-compression bonded LEDs and Sn-Ag-Cu reflow bonded LEDs. For the Au-Sn thermo-compression bonding, bonding pressure and bonding temperature were 50 N and 300oC, respectively. For the SAC solder reflow bonding, peak temperature was $255^{\circ}C$ for 30 sec. The shear strength of the Au-Sn thermo-compression joint was $3508.5gf/mm^2$ and that of the SAC reflow joint was 5798.5 gf/mm. After the shear test, the fracture occurred at the isolation layer in the LED chip for both Au-Sn and SAC joints. Thermal resistance of Au-Sn sample was lower than that of SAC bonded sample due to the void formation in the SAC solder.

• Journal of Life Science
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• v.28 no.1
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• pp.68-77
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• 2018

The purpose of this study was to isolate the probiotic lactic acid bacteria, and verify the possibility of the final selection strain as probiotic material. For screening of biogenic amines non-producing microorganisms, 42 lactic acid bacteria were isolated from various berries, extract and vinegar grown in Sunchang. Isolates were investigated for various physiological activities such as extracellular enzyme, antimicrobial and antioxidant activities, and 5 isolates were firstly screened. SBB07 was finally selected by analyzing the biogenic amine, and named Lactobacillus brevis SBB07 by 16S rRNA sequencing analysis. Next, SBB07 was assayed for their survival ability when exposed to acidic and bile conditions as well as heat and antibiotic resistance. As a result, SBB07 showed more than 86% and 54% higher survival rate in acidic condition at pH 2.0 and bile resistance with 0.5% oxgall. In addition, SBB07 showed a survival rate of more than 113% in $60^{\circ}C$, and also confirmed that it has resistant to various antibiotics. As a result of confirming the possibility of prebiotics, SBB07 showed the best utilization of GOS as a prebiotic substrate, and utilization of FOS and inulin were also high. These results suggest that SBB07 have good potential for application as probiotic lactic acid bacteria.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.360-366
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• 2013

This study was it conducted on effluent or river water close to discharge locations from a treatment plant, which were analyzed for the presence, phenotype and antibiotic resistance rates of Vancomycin Resistant Enterococci (VRE). The test results for isolation and identification of Enterococcus spp. showed that they all were VRE positive, with a total of 32 strains detected. Multiplex PCR was conducted for 32 strains, each of which were identified as E. faecium, and the results indicated that they were all confirmed as VRE, corresponding to the Van A phenotype. The results of E. faecium concentrations measured at various locations indicated that they were, on average, higher at the location of sewage treatment plants. The frequency of positive tests as well as the number of colonies was higher downstream of treatment plants. The minimum inhibitory concentration was inspected for 26 strains of discharged water samples from sewage water treatment plants, and 6 strains of river samples. Out of 19 antibiotics, 14 and 5 species showed resistance and sensitivity, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.927-932
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• 1994

A total of 34 Salmonella sp. an d25 Shigella sp. were isolated from 311 patients with diarrhea. The isolation rates of Salmonella sp. ad Shigella sp. were 10.9% and 8%, respectively. The serogroups of 34 Salmonella sp. were in order of group D(50%), group B(38.25), group E(8.8%) and group C 92, 9%0. the serogroups of 25 Shigella sp. were group D(96%) and group B(4%). Seasonal distribution of isolated Salmonella sp. and Shigella sp. were shown the most high at July, 17.65% and 64%, respectively. Age group distribution of isolated Salmonella sp. and Shigella sp. were shown the most high at twenties and thirties (23.5%), and teens(76%), respectively. The Salmonella isolates were resistant in order of prevalence use of streptomycin(SM) (100%), erythromycin (EM) and movobiocin (NB)(90.6%), penicillin G(PG) (65.6%) and cephalexin (CPX)(46.9%). the isolates of Shigella sp. were resistant in order of prevalence use of EM (95.8%), NB(91.7%), SM(87.5%). Eighteen kinds of resistant patterns of Salmonella ioslates were detected. The multiple resistance patterns of Shigella isolates were mostly SM, EM, NB type (79.2%). The minimum inhibitory concentration of Salmonella sp. and Shigella sp. and Shigella sp. isolated from patients with diarrhea were tabulated.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.218-224
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• 1988

For the optimization of thermal processing conditions in soymilk process, 4 strains of thermoresistant flat-sour bacteria were isolated from soymilk. The isolates were aerobic spore-forming rods, and grew at $-65^{\circ}C$. Based on the morphological and physiological properties, all of the isolated strains were identified as Bacillus stearothermophilus. The heat resistance of spores of 3 isolates and Bacillus stearothermophillus ATCC 12980 as a reference was determined in soymilk(pH 7.0) and pH 7.0 buffer solution. For each of the spores studied, linear regression equations with standard error were presented for the thermal destruction at 110, 115, 121, and $125^{\circ}C$. It was not obvious that the components of soy milk increased the heat resistance of spores. Between the strains studied, variability was noted in the D values at the different temperature, and no one strain was consistently the most heat resistant at all the given temperatures. The average D value for the 4 strains was 77.27, 20.20, 2.76 and 1.39 min at 110, 115, 121 and $125^{\circ}C$, respectively, and the average z value was $8.36^{\circ}C$.

• Korean Journal of Veterinary Service
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• v.32 no.1
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• pp.49-59
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• 2009

At the present study, it was aimed to explore the states of antimicrobial resistant Salmonella spp. isolates from 3,850 pigs (2,732 ileocecocolic lymphnodes and 1,118 cecal contents) and 1,764 cattle (965 cecal lymphnodes and 799 cecal contents) slaughtered in Busan province from December 2000 to November 2001. Among 5,614 samples, 457 of Salmonella spp. were isolated from pig lymphnodes (13.5%), pig cecal contents (4.4%), cattle lymphnodes (3.5%) and cattle cecal contents (0.5%). Salmonella spp. were showed different isolation ratio, that was 10.8% in summer, 9.0% in autumn, 8.4% in spring and 5.0% in winter. As a result of serotyping, B group (65.4%) were identified as the most common in pigs and cattle, in order of $C_1$ (14.0%), $D_1$ (5.5%), $C_2$ (4.2%), $E_1$ (4.2%) and L (3.5%). 34 serotypes were found, among them, Salmonella Typhimurium (S. Typhimurium) (21.0%) was the most common serotype from pigs and cattle. The major serotypes were in order of S. Derby (15.3%), S. Schwarzengrund (14.7%), S. Typhimurium var Copenhagen (9.2%), S. Mbandaka (5.7%), S. Enteritidis (5.5%) and S. Ruiru (3.5%). The most common serotype was S. Typhimurium in pigs, and S. Ruiru in cattle. S. Ruiru was firstly isolated from pigs and cattle in Korea. In antimicrobial susceptibility test, all the isolates were demonstrated susceptibility to norfloxacin and ofloxacin. But the isolates were showed resistance other antibiotics in order of doxycycline (68.3%), tetracycline (67.8%), penicillin (54.5%) and streptomycin (52.5%). S. Typhimurium were exhibited resistance to ampicillin (34.8%), chloramphenicol (36.2%), streptomycin (94.9%), sulfamethoxazole/trimethoprim (34.8%) and tetracycline (97.8%). There were 53 strains (38.4%) which had multi drug resistant (MDR) isolates, resistant to more than 6 antimicrobial agents. The most common resistance patterns of MDR isolates were ampicillin, chloramphenicol, carbenicillin, doxycycline, nalidixic acid, penicillin, streptomycin, sulfamethoxazole/trimethoprim and tetracycline (ACCbDNaPSSuT).

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.251-256
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• 2017

Some rhizobacteria were isolated, that have copper resistance and can confer copper resistance to plants allowing growth under copper stress. Isolated strains Pseudomonas veronii MS1 and P. migulae MS2 produced 0.13 and 0.26 mmol/ml of siderophore, that is a metal-chelating agent, and also showed 64.6 and 77.9% of biosorption ability for Cu in 20 mg/L Cu solution, respectively. Copper can catalyze a formation of harmful free radicals, which may cause oxidative stress in organisms. Removal activity of 1,1-diphenyl-2-picryl hydrazyl radical and antioxidant capacity of strains MS1 and MS2 increased up to 82.6 and 78.1%, respectively compared to those of control at 24 h of incubation. They exhibited 7.10 and $6.42{\mu}mol$ ${\alpha}$-ketobutyrate mg/h of 1-aminocyclopropane-1-carboxylic acid deaminase activity, respectively, which reduced levels of stress hormone, ethylene in plants, and also produced indole-3-acetic acid and salicyclic acid that can help plant growth under abiotic stress. All these results indicated that these copper-resistant rhizobacteria could confer copper resistance and growth promotion to plants.