• Current Optics and Photonics
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• v.3 no.2
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• pp.143-149
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• 2019

Shape ellipticity dependence of the exciton fine energy levels in CdTe and CdSe nanocrystal quantum dots were compared theoretically by considering the crystal structure and the Coulomb interaction of an electron and a hole. While quantum dot ellipticity changes from an oblate to prolate quantum dot via spherical shape, both the fine energy levels and the dipole moment in wurtzite structure of a CdSe quantum dot change linearly for ellipticity. In contrast, CdTe quantum dots were found to show a level crossing between the bright and dark exciton states with a significant change of the dipole moment due to the cubic structure. Shape ellipticity dependence of the optical nonlinearities in CdTe and CdSe nanocrystal quantum dots was also calculated by using semiconductor Bloch equations. For a spherical shape quantum dot, only $1^L$ dominates the optical nonlinearities in a CdSe quantum dot, but both $1^U$ and $0^U$ contribute in a CdTe quantum dot. As excitation pulse area becomes strong (${\sim}{\pi}$), the optical nonlinearities of both CdSe and CdTe quantum dots are mainly governed by absorption saturation. However, in the case of a prolate CdTe quantum dot, the real part of the nonlinear refractive index becomes relatively significant.

• Journal of radiological science and technology
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• v.38 no.1
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• pp.39-49
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• 2015

One of properties which X-ray and Neutron can be applied nondestructive test is penetration into the object with interaction leads to decrease in intensity. X-ray interaction with the matter caused by electrons, Neutron caused by atoms. They share applications in nondestructive test area because of their similarities of interaction mechanism. Grating interferometer is the one of applications produces phase contrast image and dark field image. It is defined by Talbot interferometer and Talbot-Lau interferometer according to Talbot effect and Talbot-Lau effect respectively. Talbot interferometer works with coherence beam like X-ray, and Talbot-Lau has an effect with incoherence beam like Neutron. It is important to expect the interference in grating interferometer compared normal nondestructive system. In this paper, simulation works are conducted according to Talbot and Talbot-Lau interferometer in case of X-ray and Neutron. Variation of interference intensity with X-ray and Neutron based on wave theory is constructed and calculate elements consist the system. Additionally, Talbot and Talbot-Lau interferometer is simulated in different kinds of conditions.

• Fashion & Textile Research Journal
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• v.19 no.5
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• pp.646-652
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• 2017

In order to clarify an availability of water treatment for persimmon extract dyeing, effect of color developing by water treatment process on cotton fabrics dyed with persimmon extract was investigated. Dyed fabrics were dipped still water and circulation water in various temperature. Concerning water color developing, still water color developing and circulation water color developing have been examined, and the temperature of water has been apprehended to prepare an effective basis of water color development. The surface color based on circulation water color development displays low values of $a^{\ast}$ and $b^{\ast}$, and the range of the c value(Munsell chroma) is narrow and has the value of 2 to 3, thus displays the coloration of a dark tone. The effect of temperature in water color development was insignificant, due to the small difference in temperature from $20^{\circ}C$ to $40^{\circ}C$. At $80^{\circ}C$, remarkable color development manifested, which is evidence of the high influence of temperature. The effects of circulation were clear at low temperatures, and the effects of temperature highly manifested at high temperatures. Circulation water color development display great color development at all temperatures to allow industrial color development with the absence of sunlight, thereby having an effect of energy reduction and developing color in dark tones, however this also is a strength of persimmon extract concerning color diversification, and is judged to have great value of industrial and practical application.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.31-31
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• 2009

PECVD를 이용하여 제조된 미세결정질 p-i-n 실리콘 박막 태양전지에서, p 층은 태양전지의 윈도우 역할 및 그 위에 증착될 i ${\mu}c-Si:H$ 층의 'seed'층 역할을 수행하기 때문에, p층의 구조적 및 전기적, 광학적 특성은 태양전지의 전체 성능에 큰 영향을 미칠 수 있다. 본 연구에서는 $SiH_4$ 농도를 변화시켜 각기 다른 결정 특성을 갖는 p ${\mu}c-Si:H$층을 제조하고 그 위에 i ${\mu}c-Si:H$ 층을 증착하여 p층의 결정 특성변화와 그에 따른 i ${\mu}c-Si:H$ 층 및 'superstrate' p-i-n 미세결정질 실리콘 박막 태양전지의 특성 변화를 조사하였다. P층의 경우, $SiH_4$ 농도가 증가함에 따라 결정분율 (Xc)이 감소하여 비정질화되었으며 그에 따라 dark conductivity가 감소하는 경향을 나타내었다. 각기 다른 결정분율을 가지는 p 'seed' 층 위에 증착된 태양전지는, p 'seed' 층의 결정분율이 증가함에 따라 개방전압, 곡선인자, 변환효율이 경향적으로 감소하였다. 이는 p 층 결정분율 변화에 따른 p/i 계면특성 저하 및 그 위에 증착되는 i ${\mu}c-Si:H$ 층의 결함밀도 증가 등에 따른 태양전지 특성 감소 때문인 것으로 판단되며, 이를 분석하기 위하여 i ${\mu}c-Si:H$ 층의 전기적, 구조적 특성 분석 및 태양전지의 dark I-V 특성 등을 분석하고자 한다.

• Journal of The Korean Astronomical Society
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• v.48 no.1
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• pp.21-55
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• 2015

If the Universe is dominated by cold dark matter and dark energy as in the currently popular ${\Lambda}CDM$ cosmology, it is expected that large scale structures form gradually, with galaxy clusters of mass $M{\geq}10^{14}M_{\odot}$ appearing at around 6 Gyrs after the Big Bang (z ~ 1). Here, we report the discovery of 59 massive structures of galaxies with masses greater than a few times $10^{13}M_{\odot}$ at redshifts between z = 0.6 and 4.5 in the Great Observatories Origins Deep Survey fields. The massive structures are identified by running top-hat filters on the two dimensional spatial distribution of magnitude-limited samples of galaxies using a combination of spectroscopic and photometric redshifts. We analyze the Millennium simulation data in a similar way to the analysis of the observational data in order to test the ${\Lambda}CDM$ cosmology. We find that there are too many massive structures (M > $7{\times}10^{13}M_{\odot}$) observed at z > 2 in comparison with the simulation predictions by a factor of a few, giving a probability of < 1/2500 of the observed data being consistent with the simulation. Our result suggests that massive structures have emerged early, but the reason for the discrepancy with the simulation is unclear. It could be due to the limitation of the simulation such as the lack of key, unrecognized ingredients (strong non-Gaussianity or other baryonic physics), or simply a difficulty in the halo mass estimation from observation, or a fundamental problem of the ${\Lambda}CDM$ cosmology. On the other hand, the over-abundance of massive structures at high redshifts does not favor heavy neutrino mass of ~ 0.3 eV or larger, as heavy neutrinos make the discrepancy between the observation and the simulation more pronounced by a factor of 3 or more.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.548-561
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• 2020

Paecilomyces japonica is widely cultured to produce mycelium for medicinal and health food use. Illumination is an important factor in the growth and production of mycelium in submerged culture. The effects of different light-emitting diode (LED) combinations on the growth and cordycepin content as bioactive substances of mycelium were investigated. The results showed that the mycelium dry weights were lower under dark condition and red LED treatments. Dark condition, fluorescent light, and ultraviolet-A failed to increase the cordycepin content. Blue light was necessary to increase the cordycepin content, and a red-to-blue ratio of 3:7 induced the highest cordycepin content. The cordycepin contents of mycelium in submerged culture were significantly higher in a 12 h/day illumination time under red and blue (red-to-blue ratio of 3:7) LED treatments, showing an increase of up to 38% compared with those under the fluorescent-light control condition. The results demonstrated the roles of light with different wavelengths on the biosynthesis of cordycepin as bioactive substances. The low-heat release and replacement of traditional fluorescent lights with low-energy-consuming LEDs could increase the contents of bioactive substances. After optimization of the cordycepin production using response surface methodology (Box-Behnken design) to its canonical form, the optimum combination was found to be as follows: illumination time = 17.7 h/day, sugar content in the medium = 9.7 g/50 mL, and incubation time = 61.2 h. The model predicted a maximum response of 3779.2 ㎍/mL cordycepin yield.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.51-54
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• 1999

Hydrogenated amorphous silicon (a-Si:H) films are fabricated by Argon radical annealing (ArRA). The deposition rate of continuously deposited a-Si:H film is 1.9 $\AA$/s. As ArRA time are increased to 0.5 and 1 minute, the deposition rate are increased to 2.8 $\AA$/s and 3.3 $\\AA$/s. The deposition rate of a-si:H films with 2 and 3 minutes ArRA time are 3.3 $\AA$/s. As the ArRA time is increased, the optical band gap and the hydrogen contents in the a-Si:H films are increased and slightly decreased. The light-induced degradation of ArRA treated a-Si:H films are less than that of continuously deposited a-Si:H film. The dark conductivity and the conductivity activation energy ($E_a$) of continuously deposited a-Si:H film are decreased to 1/25 in room temperature and increased to 0.09eV By 1 hour light soaking, respectively. The dark conductivity and $E_a$ of ArRA treated a-Si:H film decreased to 1/3 in room temperature and increased to 0.03eV by 1 hour light soaking, respectively. We could improve the stability of a-Si:H films under the light soaking by ArRA technique and discussed the microscopic process of ArRA technique.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.278-286
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• 2023

The present work evaluated the production of biohydrogen under mesophilic and thermophilic conditions through dark fermentation of palm oil mill effluent (POME) in batch mode using the design of experiment methodology. Response surface methodology (RSM) was applied to investigate the influence of the two significant parameters, POME concentration as substrate (5, 12.5, and 20 g/l), and volumetric substrate to inoculum ratio (1:1, 1:1.5, and 1:2, v/v.%), with inoculum concentration of 14.3 g VSS/l. All the experiments were analyzed at 37 ℃ and 55 ℃ at an incubation time of 24 h. The highest chemical oxygen demand (COD) removal, hydrogen content (H₂%), and hydrogen yield (HY) at a substrate concentration of 12.5 g COD/l and S:I ratio of 1:1.5 in mesophilic and thermophilic conditions were obtained (27.3, 24.2%), (57.92, 66.24%), and (6.43, 12.27 ml H₂/g COD_rem), respectively. The results show that thermophilic temperature in terms of COD removal was more effective for higher COD concentrations than for lower concentrations. Optimum parameters projected by RSM with S:I ratio of 1:1.6 and POME concentration of 14.3 g COD/l showed higher results in both temperatures. It is recognized how RSM and optimization processes can predict and affect the process performance under different operational conditions.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.2
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• pp.95-102
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• 2013

There was a study for biological characteristics, except for physico-chemical and mineralogical properties, on the natural bentonite that is considered as a buffer material for the high-level radioactive waste disposal site. A bentonite slurry that was prepared from a local 'Gyeongju bentonite' in Korea was incubated in a serum bottle with nutrient media over 1 week and its stepwise change was observed with time. From the activated bentonite in the nutrient media, we can find a certain change of both solid and liquid phases. Some dark and fine sulfides began to be generated from dissolved sulfate solution, and 4 species of sulfate-reducing bacteria (SRB) were identified as living cells in samples that were periodically taken and incubated. These results show that sulfate-reducing (or metal-reducing) bacteria are adhering and existing in the powder of bentonite, suggesting that there may be a potential occurrence of longterm biogeochemical effects in and around the bentonite buffer in underground anoxic environmental conditions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.3
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• pp.670-679
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• 2004

Bulbus lilii syndrome is characterizes by bitter taste, dark urine, indistint and weak pulse for rapture and unstable of mental. It is caused by not be recovered of vital energy after severe illness or mental stress. Bulbus lilli syndrome is similar to depression insomnia but not same. The name of Bulbus lilli syndrome is originated to be cured by Lily Bulb.