• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.42.4-43
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• 2020

The hydrogen-rich envelope mass of a dying massive star is the key factor that determines the type and properties of the resulting supernova. Emulating wind-driven mass loss of single stars with the MESA(Modules for Experiments in Stellar Astrophysics) stellar evolution code, we made a grid of models for a large parameter space of initial mass (12 M⊙ to 30M⊙), metallicity (solar, LMC and SMC), hydrogen envelope mass (0.01M⊙ to 10M⊙) for progenitor stars in their final step of evolution. Our results suggest the final luminosity of the progenitor is largely determined by the initial mass, which means there is luminosity degeneracy for stars with the same initial mass but with different hydrogen-rich envelope masses. Since we can break this degeneracy by correcting luminosity with surface gravity (spectroscopic HR diagram), we can infer the exact mass property of an observed progenitor. The surface temperature drastically varies near the envelope mass of ~0.1M⊙ and surface temperature of ~10000 K, where the demarcation between the hydrogen-rich envelope and the helium core lies, which explains the rarity of 'white' supergiants. There also exists a discontinuity in the chemical composition of the progenitor envelope around this critical hydrogen-rich envelope mass of ~0.1 M⊙, which can be tested in future observations of "flash spectroscopy" of supernovae.

• Animal cells and systems
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• v.2 no.3
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• pp.341-349
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• 1998

To analyze the effects of surfactants on the biosynthesis of galactolipid and the composition of fatty acids, the chloroplast envelope and thylakoid membrane were cultivated in medium treated with anionic surfactants, such as linear alkylbenzene sulfonate (0.002%, LAS), a-olefin sulfonate (O.01%, AOS), and sodium lauryl ether sulfate (0.08%, SLES), respectively. During the cultivation, the chloroplast envelope and thylakoid membrane were isolated from the cells collected at the early and middle phase of the culture and the contents of their fatty acid composition were compared with the control. When treated with surfactants, the contents of total lipid MDGD methylesters, and DGDG methylesters decreased significantly when compared with the control. It was also confirmed that more unsaturated fatty acids were involved in the biosynthesis of galactolipid. The fatty acids utilized in the biosynthesis of MGDG were in the chloroplast envelope and in the control, and linoleic acid in LAS, linolenic acid and oleic acid in AOS, and linolenic acid and oleic acid in SLES. The fatty acids in the biosynthesis of DGDG were linolenic acid and oleic acid in the control linolenic acid and stearic acid in LAS, oleic acid and linolenic acid in AOS, oleic acid and linolenic acid in SLES. In the thylakoid membrane, the major fatty acids in the biosynthesis of MGDG were linolenic acid and oleic acid in the control, oleic acid and linolenic acid in LAS, linolenic acid and linoleic acid in AOS, linolenic acid and palmitoleic acid in SLES. The fatty acids in the biosynthesis of DGDG were linolenic acid and oleic acid in the control, oleic acid and linolenic acid in LAS, linolenic acid and linoleic acid in AOS, palmitoleic acid and oleic acid in SLES.

• KIEAE Journal
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• v.13 no.2
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• pp.53-60
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• 2013

This study examined the building envelope structure used in small housings near urban area which have not good energy source in relation to the application of passive design for energy saving of small-sized architectural design firms in local cities and aimed to provide the basic materials of future design direction of designers and housing owners by analyzing economy of a project in order to know the amount of energy saving and additional expenses depending on the building envelope pattern. As a result of comparing and examining the energy saving cost from the period of use compared to investment by the thickness of insulating materials based on building envelope pattern for energy saving, it was found that the thicker the insulating materials are, the more energy saving amount is. While the current bead-type insulating materials have short payback period due to low initial investment, extruded insulating materials show the difference of five years compared to bead-type insulation because of its high initial investment.

• Journal of Environmental Health Sciences
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• v.20 no.2
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• pp.80-89
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• 1994

The effects of amphotericin B (150 $\mu$g/ml) and cycloheximide (10 $\mu$g/ml) on the biosynthesis of phospholipid and their fatty acid composition in chloroplast isolated from Chlorella were analyzed to compare with control. The levels of total lipid, phosphatidylethanolamine (PE), and phosphatidylcholine (PC) in the group treated with antibiotics were decreased. However, the biosynthesis of phosphatidylinositol (PI) was not affected by antibiotics. The major fatty acid in chloroplast envelope was linolenic acid (27.71%) in control and stearic acid (21.59%) in the group treated with amphotericin B. It was showed that the group treated with cycloheximide contained more unsaturated fatty acid than the control.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.237.2-237
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• 1997

No Abstract, See Full Text

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.308-314
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• 1999

We used the photoreflectance spectroscopy for characterization of the infrared photodetector structure we GaAs/$Al_{0.3}Ga_{0.7}As$ multi-quantum well (MQW) structures grown by molecular beam epitaxy (MBE) method. Energy gap related transitions in GaAS and AlGaAs were observed. The Al composition(x) was determined b Sek's composition formula. MQW related transition energies were identify the transitions, the experimentally observed energies were compare with results of the envelope function approximation for a rectangular quantum well.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.1
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• pp.21-27
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• 2000

We used the surface photovoltage spectroscopy(SPVS) for characterization of GaAs/Al\ulcornerGa\ulcornerAs multi-quantum well(MQW) structures grown by molecular beam epitaxy(MBE) method. Energy gap related transitions in GaAs and AlGaAs were observed. The Al composition(x=0.3) was determined by Sek's composition formula. Transition energies in MQW were determined using the differential surface photo-volatage spectroscopy)DSPVS) of the measured resonanced. In order to indentify the transitions, the experimentally observed energies were compared with results of the envelope function approximation for a rectangular quantum well. We have observed and interesting behavior of the temperature dependence(80K~300K) of the 11Hand 11L transition for sample.

• Korean Journal of Materials Research
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• v.10 no.10
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• pp.698-702
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• 2000

The characteristics of optical absorption in $Al_{0.24}Ga_{0.76}As/GaAs$ multi-quantum wells(MQWs) structure were investigated by using the surface photovoltage(SPV). The Spy features near 1.42 eV showed two overlapping signals. By chemical etching, we found associated with the GaAs substrate and the GaAs cap layer. The Al composition(x=24 %) was determined by Kuech's composition formula. In order to identify the transition energies. the experimentally observed energies were compared with results of the envelope function approximation for a rectangular quantum wells An amplitude variation of the relative Spy intensity from the GaAs substrate, llH, and llL was observed at different light intensities. A variation in the SPY line shape of the transition energies were observed with decreasing tempera­t ture.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.35-40
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• 1995

Considering the higher discharge burnup, lower channel refuelling rate, lower linear element rating(LER), lower coolant void reactivity and axial power shape, CANFLEX-RU fuel bundle is optimized for CANDU-6 by grading the fissile composition in the ring-wise of the bundle and by applying fuel management scheme appropriately. The fissile composition of the fuel bundle is graded as the recovered uranium (0.9 w/o U-235) in the outer and intermediate elements, depleted Uranium (0.2 w/o U-235) in the center element, natural uranium (0.71 w/o U-235) in the inner elements. Enrichment is not required for these fuel. The fissile composition is optimized by lattice calculation and by time-averaged reactor simulation. CANFLEX-RU optimized for CANDU-6 resulted to be the 15% lower channel refuelling rate, acceptable axial power profile and power envelope, 70% higher discharge burnup, 15% lower LER and not increase coolant void reactivity compared with the 37-element natural uranium bundle for CANDU-6.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.221-231
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• 1998

The biosynthesis of galactolipid and the composition of fatty acid in chloroplast and thylakoid envelope isolated from C. ellipsoidea treated with antiseptics (potassium sorbate: PS, sodium benzoate:SB, calcium propionate:CP) were analyzed. The contents of monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and total lipid in treatment with antiseptics were lower to compared with the control. The major fatty acid utilized for biosynthesis of MGDG in chloroplast envelope were palmitoleic acid (ave. 15.55%), oleic acid (ave. 15.09%) in control. Otherwise, the major fatty acids in P.S treatment were utilized for oleic acid (ave. 13.71%), linolenic acid (ave. 14.36%), palmitoleic acid (ave. 18.26%), oleic acid (ave. 17.26%) in S.B treatment, and oleic acid (ave. 16.88%), palmitoleic acid (ave. 16.31%) in CP treatment. It was showed that the major fatty acids in chloroplast envelope DGDG were oleic acid (ave. 15.75%), linolenic acid (ave. 17.74%) in control, oleic acid (ave. 14.90%), palmitoleic acid (ave. 15.97%) in P.S treatment, palmitoleic acid (ave. 13.29%), oleic acid (ave. 15.74%) in S.B treatment, and oleic acid (ave. 14.52%), palmitoleic acid (ave. 14.03%) in C.P treatment. The major fatty acid utilized for biosynthesis of MGDG in thylakoid envelope were linolenic acid (ave. 14.78%), oleic acid (ave. 12.90%) in control. Otherwise, the major fatty acids were utilized for palmitoleic acid (ave. 13.00%), palmitic acid (ave. 13.00%) in P.S treatment, palmitoleic acid (ave. 12.94%), oleic acid (ave. 12.43%) in S.B treatment, and oleic acid (ave. 12.43%), palmitoleic acid (ave. 12.43%) in C.P treatment. It was showed that the major fatty acids in thylakoid envelope DGDG were linolenic acid (ave. 18.01 %), oleic acid (ave. 15.53%) in control, linolenic acid (ave. 19.20%), linoleic acid (ave. 14.14%) in P.S treatment, palmitoleic acid (ave. 9.03%), oleic acid (ave. 14.85%) in S.B treatment, oleic acid (ave. 13.90%), linolneic acid(ave. 12.66%) in C.P treatment.