• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.117-124
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• 2003

Pre-launch calibration data have been analyzed for evaluating the point spread function (PSF) of Yohkoh Soft X-ray Telescope (SXT). Especially, it is found crucial that the effect of undersampling should be treated properly. The best fit solution of the SXT PSF, which is modeled by an elliptical Moffat function, has been derived by the comparison with the ground experiment data. In order to examine the off-axis variation of the SXT PSF, we need to define in advance the location of the optical axis on the CCD. According to the previous studies, the off-axis variation of effective area (the vignetting function) may be approximated either by two non-concentric cones or by a cone with some flat distortions. There have been, however, no fully approved representations for the SXT vignetting effect. The effect of the shift of the optical axis from the geometrical center of the telescope is investigated by numerical simulation. It is revealed from our study that the full width at half maximum (FWHM) of the SXT PSF stays nearly constant within an error bound over the central area of the CCD where the solar disk is located.

• Korean Journal of Veterinary Research
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• v.22 no.2
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• pp.161-165
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• 1982

Biochemical and antimicrobial susceptibility tests were conducted on 40 strains of Pseudomonas aeruginosa originated from diseased chicken submitted for diagnosis to this Institute during 1978-80. An extensive study of the biochemical properties revealed that the tested strains can be identified with Pseudomonas aeruginosa. Antibiogram showed that all the strains were susceptible to gentamicin, colistin and amikacin but resist to nitrofurantoin, trimethoprim+sulfamethoxazole, ampicillin, methicillin and kanamycin, and had varing degreed of resistance to other antimicrobials including carbenicillin, sulfomamides, neomycin, streptomycin, tetracycline and chloramphenicol. Three of the most frequent resitance patterns observed were FM SXT AM ME KM CM TC SM NE SSS Pattern, FM SXT AM ME KM CM TC SM NE SSS CB Pattern and FM SXT AM EKM CM TC SM Pattern, and these resistance patterns contained 72.5% of the tested strains.

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.277-285
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• 2006

Plasmids are covalently closed circular molecules of DNA that are stably inherited and replicate somewhat independently of the bacterial chromosome. Genes carried on plasmids can mediate a wide variety of important functions, including antibiotics (R plasmids) and heavy metals resistance, toxins production, cell penetration, iron chelation, complement resistance, and metabolic characteristics such as sucrose and lactose fermentation. Fifty strains of lactobacilli were isolated from 26 staters and 29 fermented milk products. They were classified 27 strains as Lactobacillus paracasei subsp paracasei, 11 stains as Lactococcus lactis subsp cremoris, 6 strains as L delbrueckii subsp lactis, 4 strains as L acidophius, and 2 strains as L delbrueckii subsp bulgaricus. All of these strains were examined for drug resistance and transferability of R plasmids. All of the isolates were sensitive to Am, C, CF, E, NB, P, T, and Te. But resistant to SXT 94% (47 strains), K 66% (33 strains), S 56% (28 strains), ENR 50% (25 strains), NOR 38% (19 strains) CIP 38% (19 strains), GM 16% (8 strains), and N 14% (7 strains), in order. And 32 different resistant patterns were found. The most frequently encountered patterns were CIP-ENR-K-NOR-S-SXT (5 strains). In vitro R plasmids transfer experiment, 57 antibiotic resistant strains which were not transfer to the recipient 2 Escherichia coli strains by conjugation, These results indicate that Lactobacillus in internal trade market' stater recognize R factor but transmissible R plasmid is not existed.

• Journal of The Korean Astronomical Society
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• v.41 no.6
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• pp.181-186
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• 2008

Recently, Choe & Cheng (2002) have demonstrated that multiple magnetic flux systems with closed configurations can have more magnetic energy than the corresponding open magnetic fields. In relation to this issue, we have addressed two questions: (1) how much fraction of eruptive solar active regions shows multiple flux system features, and (2) what winding angle could be an eruption threshold. For this investigation, we have taken a sample of 105 front-side halo CMEs, which occurred from 1996 to 2001, and whose source regions were located near the disk center, for which magnetic polarities in SOHO/MDI magnetograms are clearly discernible. Examining their soft X-ray images taken by Yohkoh SXT in pre-eruption stages, we have classified these events into two groups: multiple flux system events and single flux system events. It is found that 74% (78/105) of the sample events show multiple flux system features. Comparing the field configuration of an active region with a numerical model, we have also found that the winding angle of the eruptive flux system is slightly above $1.5{\pi}$.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.171-177
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• 2004

X-ray plasma ejections often occurred around the impulsive phases of solar flares and have been well observed by the SXT aboard Yohkoh. Though the X-ray plasma ejections show various morphological shapes, there has been no attempt at classifying the morphological groups for a large sample of the X-ray plasma ejections. In this study, we have classified 137 X-ray plasma ejections according to their shape for the first time. Our classification criteria are as follows: (1) a loop type shows ejecting plasma with the shape of loops, (2) a spray type has a continuous stream of plasma without showing any typical shape, (3) a jet type shows collimated motions of plasma, (4) a confined ejection shows limited motions of plasma near a flaring site. As a result, we classified the flare-associated X-ray plasma ejections into five groups as follows: loop-type (60 events), spray-type (40 events), jet-type (11 events), confined ejection (18 events), and others (8 events). As an illustration, we presented time sequence images of several typical events to discuss their morphological characteristics, speed, CME association, and magnetic field configuration. We found that the jet-type events tend to have higher speeds and better association with CMEs than those of the loop-type events. It is also found that the CME association (11/11) of the jet-type events is much higher than that (5/18) of the confined ejections. These facts imply that the physical characteristics of the X-ray plasma ejections are closely associated with magnetic field configurations near the reconnection regions.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.87.1-87.1
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• 2011

Since early 90's, the solar X-ray telescopes such as Yohkoh SXT and Hinode XRT have observed coronal magnetic structures on the Sun's surface in the range of about $40'{\times}40'$ field-of-view (FOV) covering the full solar disk. Thus it has been stressed by the scientists that the optical structure of solar telescopes should be designed with care for improving the uniformity over a wide FOV. There would be, however, no unique solution in designing the optical system of a telescope for overcoming perfectly the problem of off-axis response variation. As a consequence, the correction of optical imperfectness of telescopes has become an important calibration step that should be performed beforehand when the observed images are to be used for photometric purposes. In particular, a special care should be taken when performing the temperature analysis with thin and thick filters for flaring activities observed at the periphery of the full FOV. From the analyses of both pre-launch calibration and in-flight observation data, the optical characteristics for describing the performance of solar X-ray telescopes, especially in view of their energy dependence, will be introduced and discussed in our presentation.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.9-14
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• 2010

In this study, lactic acid bacteria with high angiotensin converting enzyme inhibitor activity were isolated from Korean fermented food, such as kimchi and salted seafood. The strain HLJ59, isolated from salted shrimp showed the highest angiotensin converting enzyme inhibitor activity in DeMan Rogosa Sharpe broth. Optimum growth temperature of Lactobacillus brevis HLJ59 was at $34^{\circ}C$. Acid treatment at pH 3.0 for 1.5 h decreased cell viability from $9.9{\times}10^8$ CFU/ml to $3.11{\times}10^4$ CFU/ml. The bile extract concentration of 0.3%, 0.5%, and 1.0% in MRS broth did not inhibit the growth of HLJ59. Isolated strain HLJ59 showed more sensibility to amikacin, gentamycin, neomycin, streptomycin, kanamycin, cefmetazole, cephalothin, ampicillin, ticarcillin, sulbactam+ampicillin, amoxicillin+clavulanic acid (AMC), tetracycline, and sulfamethoxazole+trime thoprim (SXT) as compare to other 7 different antibiotics. However, it showed more resistance to cefoxatin, ceftnaxone, penicillin, ciprofloxacin, nalidixic acid, lincomycin, and chloramphenicol.