• 천문학회지
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• 제37권5호
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• pp.295-297
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• 2004

Observations with EUVE, ROSAT, and BeepoSAX have shown that some clusters of galaxies produce intense EUV emission. These findings have produced considerable interest; over 100 papers have been published on this topic in the refereed literature. A notable suggestion as to the source of this radiation is that it is a 'warm' (106 K) intracluster medium which, if present, would constitute the major baryonic component of the universe. A more recent variation of this theme is that this material is 'warm-hot' intergalactic material condensing onto clusters. Alternatively, inverse Compton scattering of low energy cosmic rays against cosmic microwave background photons has been proposed as the source of this emission. Various origins of these particles have been posited, including an old (${\~}$Giga year) population of cluster cosmic rays; particles associated with relativistic jets in the cluster; and cascading particles produced by shocks from sub-cluster merging. The observational situation has been quite uncertain with many reports of detections which have been subsequently contradicted by analyses carried out by other groups. Evidence supporting a thermal and a non-thermal origin has been reported. The existing EUV, FUV, and optical data will be briefly reviewed and clarified. Direct observational evidence from a number of different satellites now rules out a thermal origin for this radiation. A new examination of subtle details of the EUV data suggests a new source mechanism: inverse Compton scattered emission from secondary electrons in the cluster. This suggestion will be discussed in the context of the data.

• 천문학회보
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• 제40권2호
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• pp.52.1-52.1
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• 2015

FIMS/SPEAR is a dual-channel far-ultraviolet imaging spectrograph on board the Korean microsatellite STSAT-1, which was launched on 2003 September 27. The primary mission goal of FIMS was to conduct a survey of diffuse far UV emissions in our Galaxy. For this purpose, FIMS completed a survey of about 84% of the sky during its operation of a year and a half. The present study aims to analyze this survey data made in the far UV wavelengths to understand the global evolution of our Galaxy. The far UV wavelength band is known to contain important cooling lines of hot gas: hence, the study will show how the hot gas in our Galaxy, produced by stellar winds and supernova explosion, evolves globally to cool down and become mixed with ambient cooler medium. One of the main findings from previous analyses of the FIMS data is that molecular hydrogen exists ubiquitously in our Galaxy. This discovery leads to another important scientific question: how is molecular hydrogen distributed in our Galaxy and how does it affect globally the evolution of our Galaxy as a cold component? Hence, the present study will cover both the hot and cold components of the ISM, which will also provide the opportunity to investigate the interactions between the two.

• BMB Reports
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• 제30권3호
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• pp.167-172
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• 1997

The yeast Saccharomyces cerevisiae, mutant CH117, shows a drug-hypersensitivity (dhs) to cycloheximide, bleomycin, actinomycin D, 5-fluorouracil. nystatin, nigericin and several other antibiotics. CH 117 was also temperature-sensitive (ts). being unable to grow at $37^{\circ}C$ and secreted more invertase and acid phosphatase into the medium than the parent yeast. CH117 grows very slowly and the cell shape is somewhat larger and more sensitive to zymolyase than the wild type cells. Light microscopic and electron microscopic observation also revealed abnormality of the mutant cell wall. These characteristics indicate that CH117 has a defect in an essential component of the cell surface and that the cell wall which performs barrier functions has become leaky in the mutant. We screened a genomic library of wild type yeast for clones that can complement the mutation of CH117. A plasmid, pCHX1, with an insert of 3.6 kilobases (kbs) could complement the dhs and ts of CH117. Deletion and subcloning of the 3.6 kb insert showed that a gene for the complementation of mutant phenotypes was located in 1.9 kbs Puvll-Hindlll fragment.

• 품질경영학회지
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• 제40권1호
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• pp.60-72
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• 2012

This research conducted a survey targeting mobile SNS users in order to see whether mobile SNS attribute( accessibility, usefulness, newness, connectivity) through the medium of information share and relationship formation had a positive influence on user satisfaction. The results of the analysis showed that usefulness and accessibility had a significant influence on information share, while accessibility and connectivity had a significant influence on relationship formation. Information share and relationship formation both had a significant influence on user satisfaction. Based on this research, an angle of approach different from the business transactions and information services offered in existing mobile networks is necessary when corporations provide SNS through mobiles. When considering that the most important part in the use of mobile SNS is the social component, this can be actively used for the development and marketing of SNS services. Therefore, the SNS provider must focus its efforts on finding a method to stimulate user sensibilities in order to increase customer satisfaction and draw out continuous usage.

• International Journal of Safety
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• 제3권1호
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• pp.53-58
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• 2004

SMART-P is a promising advanced small and medium category nuclear power reactor. It is an integral type reactor with a sensible mixture of new innovative design features and proven technologies aimed at achieving a highly enhanced safety and improved economics. The enhancement of the safety and reliability is realized by incorporating inherent safety improving features and reliable passive safety systems. The improvement in the economics is achieved through a system simplification, and component modularization. Preliminary safety analyses on selected limiting accidents confirm that the inherent safety improving design characteristics and the safety system of SMART-P ensure the reactor's safety. SMART-P is an advanced integral pressurized water reactor. The purpose of this study is for the safety analysis of the steam generator module pipe break for the SMART-P. The integrity of the fuel rod is the major criteria of this analysis. As a result of this analysis, the safety of the RCS and the secondary system is guaranteed against the module pipe break of a steam generator of the SMART-P.

• 한국산업융합학회 논문집
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• 제2권1호
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• pp.85-90
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• 1999

The possibility of employment of ceramics, known to be emitting far infrared waves, to keep the growth and the viability of the antagonistic microorganisms was examined. Among four kinds of commercial ceramics, the ceramic powders composed of soft ferrite as a main component has exhibited to grow Pseudomonas cepacia and Saccharomyces cerevisiae better. The ceramic powder in the growth medium has increased the number of cells of P. cepada about ten times and that of S. cerevisiae two to five times more than that in the control at $27^{\circ}C$. The viability of the microorganism at low temperature which was measured from the regrowth behavior at $27^{\circ}C$ after five days store at $4^{\circ}C$ has shown that the lag time of the two microorganisms reduced about three hours without any defect in the rate of logarithmic growth. These results demonstrated that the ceramic powders was available to the growth and viability at low temperature of antagonistic microorganisms.

• 한국신뢰성학회지:신뢰성응용연구
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• 제12권3호
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• pp.153-163
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• 2012

Recently, as a electronic components are becoming more high-density, so that electronic circuits have smaller pitches between the leads and are more vulnerable to insulation failure. And the reliability of electric insulation has become an ever important issue as device contact pitches and print patterns shrink. Ion migration occurs in highly humid environment as voltage is applied to an installed print circuit. Under highly humid and voltage applied circumstances, electronic components respond to applied voltages by electrochemical ionization of metals, and a conducting filament forms between the anode and cathode across a nonmetallic medium. This leads to short-circuit failure of the electronic component. In thesis, we study acceleration test of ion migration in FR-4 PCB plated with Sn. Voltage applied test of FR-4 PCB circuits plated with Sn was tested in the temperature and humidity environments. As a result of this test, equation of acceleration model was derived.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.375-380
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• 2015

Recently, methane has attracted much attention as an alternative carbon feedstock since it is the major component of abundant shale and natural gas. In this work, we produced methanol from methane using whole cells of Methylosinus trichosporium OB3b as the biocatalyst. M. trichosporium OB3b was cultured on NMS medium with a supply of 7:3 air/methane ratio at 30℃. The optimal concentrations of various methanol dehydrogenase inhibitors such as potassium phosphate and EDTA were determined to be 100 and 0.5 mM, respectively, for an efficient production of methanol. Sodium formate (40 mM) as a reducing power source was added to enhance the conversion efficiency. A productivity of 49.0 mg/l·h, titer of 0.393 g methanol/l, and conversion of 73.8% (mol methanol/mol methane) were obtained under the optimized batch condition.

• 한국생활과학회지
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• 제12권5호
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• pp.787-795
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• 2003

This research studied several somatotypes for children's upper bodies in order to suggest the basic data of bodice patterns of children's clothing. By extracting the component factors from the children's bodices, they were classified into several somatotypes to recognize an individual body type. Three hundred and fifty eight children's wears were estimated as research objects to analyze their somatotypes for the 44 items representing upper bodies through anthropometric measurement and photometric measurement. The results are as follows : 1. Seven factors were extracted as a result of factor analysis. 2. Data were classified into three types as a result of cluster analysis : Type 1 was characterized as low fat body, small skeleton size, and forward belly ; type 2 as high fat body, normal hight, backward shoulder, and the lowered shoulders ; type 3 as medium fat body, tall height, somewhat crouching back, and the rising shoulders. 3. As a results of the discrimination analysis for the three types, the highly discriminated items were height, width of bosom, front center length. weight, width of waist or the length of waist. One could discriminate one's own body type by obtaining the classification function from these five items.

• KSBB Journal
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• 제24권1호
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• pp.59-64
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• 2009

The callus formation from inferior leaf of Aloe saponaria was induced in M & S medium supplemented with 10-30 ${\mu}M$ NAA (${\alpha}$-naphthalene acetic acid) and 3-7 ${\mu}M$ kinetin under incubation in the dark at $25^{\circ}C$ for 6 weeks. The hot water extract ($100^{\circ}C$, 24 hrs) from cultured callus was obtained and the components analysis for the extract were examined to determine the callus can synthesized the bioactive component such as Aloe polysaccharide. The freeze dried extract contained the sugar of 53.2%, protein of 7.3%, ash of 18.5% and water of 21% (w/w). Two fractions (Fr-I and Fr-II) were obtained by Sepharose CL-4B gel permeation chromatography and Fr-I, major fraction was further purified with dialysis. From sugar analysis by TLC and GC, the purified Fr-I fraction consisted of glucose (77.6%), galactose (17.7%), mannose (4.7%, w/w) and uronic acid (trace). The molecular weight of purified Fr-I fraction determined by GPC was about 110 kDa.