• Proceedings of the Korean Fiber Society Conference
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• 1986.06a
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• pp.16-16
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• 1986

• Bulletin of the Korean Chemical Society
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• v.20 no.7
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• pp.835-837
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• 1999

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.481-483
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• 1999

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.57-65
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• 2003

The formation of exit burr in drilling metals is analyzed by finite element method. The simplified burr formation model is suggested for the complex mechanism of burr formation in drilling on the basis of experimental data. Using the model the magnitude of burr is predicted and the effect of material properties of workpiece and cutting condition on burr formation is analyzed in the present study. The suggested model is verified by comparing simulation results and experimental ones. The predicted size and shape of burr are in good agreement with those observed by experiment.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.29.1-29.1
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• 2018

With their complex structure that includes a thin disc, spiral arms, and often a bar, galaxies have been regarded as something beyond the human perceptions. Hence, the studies on galaxy formation in the 20th century have almost exclusively based on schematic scenarios. With markedly improved knowledge on cosmology over the last couple of decades, we have finally acquired a base from which galaxy formation can be studied from the first principles of physics. I review the modern history of the study of galaxy formation and present some preliminary results from the most recent numerical simulations that provide more realistic pictures of galaxy formation than was available ever before. In terms of galaxy formation, the age of scenarios is fading away, while the age of physical understanding is rising over the horizon.

• Applied Microscopy
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• v.28 no.4
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• pp.603-613
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• 1998

The present study was designed in order to observe relationship between the endoplasmic reticulum and the Golgi complex during spermiogenesis of the long-fingered bat (Miniopterus schreibersi fuliginosus). The testes were obtained from adult bats and treated with the prolonged osmification or fixed with ferrocyanide reduced osmiun. In the Golgi phase, The Golgi complex shows an oval shape, and was composed of a cortex and a medullar enclosing acrosome. The Golgi vacuoles with electron-dense granules of crescent shape were fused with each other. The smooth endoplasrnic reticulum was scattered in all the area of the cytoplasm. In the cap phase, The Golgi complex was crescent in shape, and faced to a nucleus. Large and small vesicles were fused with each other, and then fused with a acrosomal vacuole. The rough endoplasmic reticulum was close to the large Golgi vacuole. In the acrosome phase, The Golgi complex was moved to behind of the acrosome face. Small vesicles were fused with an acrosome, and cisternae of the trans-face of Golgi complex was connected with an acrosome in the early acrosome phase. The smooth endoplasmic reticulum was distributed in the cytoplasm. The annulate lamellar was originated from a radial body-annulate lammellae complex. In the maturation phase, The Golgi complex with dilated cistrern appeared in the cytoplasm, and also, annulate lamellar was observed in the cytoplasm. The connection of the annulate lamellar with the cistern of radial body suggests that an annulate lamellar seems to be closely related to radial body. The smooth endoplasmic reticulum was scattered in the cytoplasm in the early Golgi phase, but annulate lamellar-radial body complex which might be a residual and disappearing form of the smooth endoplasmic reticulum appeared in the acrosome phase. The Golgi complex steadily remained in the late maturation phase when the endoplasmic reticulum began to disappear from the cytoplasm: the Golgi complex was still occurred after acrosome formation. The observations obtained in the present study, which was characterized by the presence of the Golgi complex in the late maturation phase, suggests that the Golgi complex may play an important role also even after the acrosome formation.

• Journal of Life Science
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• v.19 no.7
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• pp.852-858
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• 2009

The homeostasis of the pyridine nucleotide pool [NAD(P)H and NAD(P)$^+$] is maintained in Rhodobacter sphaeroides mutant strains defective in the cytochrome bci complex or the cytochrome c oxidases in terms of its concentration and redox state. Aerobic derepression of the puf operon, which is under the control of the PrrBA two-component system, in the CBB3 mutant strain of R. sphaeroides was shown to be not the result of changes in the redox state of the pyridine nucleotides and the ubiquinone/ubiquinol pool. Using the bc$_1$ complex knock-out mutant strain of R. sphaeroides, we clearly demonstrated that the inhibitory effect of cbb$_3$, oxidase on spectral complex formation is not caused indirectly by the redox change of the ubiquinone/ubiquinol pool.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.300-310
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• 1994

Physicochemical properties for the inclusion complex of chenodeoxycholic acid(CDCA) and it's $7{\beta}-hydroxy$ epimer ursodeoxycholic acid(UDCA) with ${\beta}-cyclodextrin({\beta}-CyD)$ were studied. The formation of the complex in the solid state were confimed by polarized microscopy and differential scanning calorimetry(DSC). Proton nuclear magnetic resonance$(^1H-NMR)$spectroscopy showed that CDCA and UDCA form an inclusion complex with ${\beta}-CyD$ in aqueous solution. The 1 : 1 stoichiometry of the complex was dextermined by the continuous variation method. From DSC and $^1H-NMR$ studies, there were not any differences between CDCA and UDCA. Complex of CDCA and UDCA showed increase in solubility and dissolution compared with CDCA and UDCA alone, respectively. Solubility pattern of UDCA complex was pH independent but, CDCA complex was like that of CDCA. Dissolution rate increased markedly in case of UDCA complex compared with CDCA complex, especially in acidic pH value.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.49.1-49.1
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• 2015

Star formation in galaxies that lie in dense environment tends to increase as the redshift of the cluster increases. At z~1.4, the situation turns to be complex; some clusters still harbor galaxies with vigorous star formation, and others are populated with relatively old, massive galaxies. We present the result from narrow-band photometric study of the fields around the radio galaxy 6CE 1100+3505 at z=1.44. Deep H- and H-narrow band data have been obtained using CFHT/WIRCAM which cover the corresponding wavelengths for redshifted $H{\alpha}$. While the number of IRAC 3.6, and $4.5{\mu}m$ selected sources show clear excess within the central ~1Mpc area from the radio galaxy, number of galaxies identified to show excess in H-narrow band is very small. We discuss the possible integrated star formation rate in this overdense structure, and the implication to the evolution of cosmic star formation rate as a function of environment.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.93-98
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• 1996

Lipopretein(a)[Lp(a)] is a macromolecular complex found in human plasma that combines structural elements composed of LDL and apo(a), and that is associated with premature coronary heart disease and stroke. In this study, various samples which consisted of normal and abnormal LDL and LP(a) were selected for compar-ison. The above samples were incubated with copper in order to oxidize and to compare atheroma formation, in vitro and free radical formation of Lp(a) was decreased compared to purified LDl. And LDL or Lp(a) from a 40 year old donor was higher in the free radical formation than that fro, a 20 years old donor. In order to investigate the macrophage foam cell formation, oxidized LDL of Lp(a) was incubated with human monocyte derived macrophage(HMDM). Oxidized samples enhanced on acceptability f foam cell formation by HMDM were compared to the control group. Also, structural change of LDL and Lp(a) against oxidation times were found from HPLC mapping.