http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A Design of Rotor Bar Inclination in Squirrel Cage Induction Motor
Heo, Chang Geun,Kim, Hui Min,Park, Gwan Soo IEEE 2017 IEEE transactions on magnetics Vol.53 No.11
<P>The shape of rotor bar is important in squirrel cage induction motor (SCIM) performance, such as starting torque, operating torque, and operating efficiency. Some designs of increasing starting torque of motor may decrease motor efficiency. Moreover, some designed shapes of bar are so complicated to be manufactured. In this paper, the design is focused on the simple inclination of conventional shape of bar with keeping the rotor bar area constant. The effects of rotor bar inclination on starting torque, operating torque, and operating efficiency in SCIM are analyzed. The results showed that there is optimum inclination of rotor bar to improve all the performances together. An application to the 3.4 kW SCIM showed that the starting torque is increased from 17.53 to 17.64 N.m, the operating torque from 11.19 to 11.26 N.m, and the operating efficiency from 94.18% to 94.81%.</P>
Inhibition of Clostridium perfringens using Bacteriophages and Bacteriocin Producing Strains
Sunhak Heo,Min Gon Kim,Mirae Kwon,Hee Soo Lee,Geun-Bae Kim 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.1
In this study, we isolated and characterized a bacteriocin-producing strain and two bacteriophages (P4, A3), showing antimicrobial effects against Clostridium perfringens, from chicken and swine feces by the spot-on-the lawn antagonism method. The selected strain was identified as Streptococcus hyointestinalis by 16S rRNA gene sequencing. The bacteriocin from the isolated strain exhibited strong inhibitory activity against four strains of C. perfringens and all the tested strains of Listeria monocytogenes, and the bacteriocin were highly heat- and pH-stable even at pH 2, pH 10 and 121°C for 15 min. We also evaluated the combined effects of the isolated bacteriocin and phages. Combining the phage treatments and bacteriocin resulted in a synergetic effect compared with the phage or the bacteriocin alone. In addition, during the probiotic test, the bacteriocin-producing S. hyointestinalis B19 strain reduced the population of C. perfringens significantly. Treatment with S. hyointestinalis B19 and a cocktail of lytic bacteriophages eradicated the C. perfringens KCTC 3269T, completely. Consequently, the isolated bacteriocin and bacteriophages represent candidates for effective biocontrol of C. perfringens, and bacteriocin-producing S. hyointestinalis B19 is a potential probiotic candidate for use in domestic animals.
Hee Soo Lee,Mirae Kwon,Sunhak Heo,Min Gon Kim,Geun-Bae Kim 한국축산식품학회 2017 한국축산식품학회지 Vol.37 No.4
This study investigated the psychrotrophic bacteria isolated from chicken meat to characterize their microbial composition during refrigerated storage. The bacterial community was identified by the Illumina MiSeq method based on bacterial DNA extracted from spoiled chicken meat. Molecular identification of the isolated psychrotrophic bacteria was carried out using 16S rDNA sequencing and their putrefactive potential was investigated by the growth at low temperature as well as their proteolytic activities in chicken meat. From the Illumina sequencing, a total of 187,671 reads were obtained from 12 chicken samples. Regardless of the type of chicken meat (i.e., whole meat and chicken breast) and storage temperatures (4°C and 10°C), Pseudomonas weihenstephanensis and Pseudomonas congelans were the most prominent bacterial species. Serratia spp. and Acinetobacter spp. were prominent in chicken breast and whole chicken meat, respectively. The 118 isolated strains of psychrotrophic bacteria comprised Pseudomonas spp. (58.48%), Serratia spp. (10.17%), and Morganella spp. (6.78%). All isolates grew well at 10°C and they induced different proteolytic activities depending on the species and strains. Parallel analysis of the next generation sequencing and culture dependent approach provides in-depth information on the biodiversity of the spoilage microbiota in chicken meat. Further study is needed to develop better preservation methods against these spoilage bacteria.
A Novel Magnetic Flux Leakage Sensor System for Inspecting Large Diameter Pipeline
Chang Geun Heo,Young Chae Kim,Jong Ho Bae,Gwan Soo Park 한국자기학회 2022 Journal of Magnetics Vol.27 No.1
The magnetic flux leakage (MFL) type non-destructive inspection can be performed only when the metal object is sufficiently magnetically saturated. Therefore, since the general MFL sensor system used for pipeline inspection must sufficiently saturate the pipe, the weight and size of MFL sensor system are inevitably increased according to the diameter or thickness of the pipe. However, if the weight of the MFL sensor system is excessively increased, it is difficult to drive, and thus it is difficult to inspect a pipe having a large diameter. In this paper, the novel MFL sensor system which can be inspected large-diameter pipes without increasing the weight of the MFL sensor system is proposed and compared to the conventional MFL sensor system used for the pipe inspection. Since the proposed MFL sensor system is a system that saturates the pipe locally, it has the advantage of being able to inspect the pipe regardless of the pipe diameter.