• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.29-32
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• 2002

This paper describes a novel structure of NMOSFET with elevated SiGe source/drain region and ultra-shallow source/drain extension(SDE)region. A new ultra-shallow junction formation technology. Which is based on damage-free process for rcplacing of low energy ion implantation, is realized using ultra-high vacuum chemical vapor deposition(UHVCVD) and excimer laser annealing(ELA).

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.610-612
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• 2008

Piston cores retrieved from the eastern part of the deep-water Ulleung Basin were analyzed to access the potential of hydrocarbon gas generation and natural gas hydrate (NGH) formation. Seismic data acquired in the study area were also analyzed to determine the presence of hydrocarbon gas and/or NGH, and to map their distribution. Core analyses revealed high total organic carbon (TOC) contents which favor hydrocarbon generation. The cores recovered from the southern study area showed the sufficient residual hydrocarbon gas concentrations for the formation of significant NGH. These cores also showed the cracks developed parallel to the bedding that suggest significant gas content in situ. A number of seismic blanking zones were observed on seismic data. They are identified as vertical to sub-vertical chimneys caused by the upward migration of pore fluid or gas, and containing of free gas and/or NGH. Often, they are associated with velocity pull-up structures that are interpreted to be the result of high-velocity NGH. The seismic data also showed several bottom-simulating reflectors (BSRs) that are associated with overlying NGH and underlying free gas. The distribution of blanking zones and BSRs would be impacted by the lateral differences of upward methane fluxes.

• 에너지공학
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• 제21권4호
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• pp.378-384
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• 2012

Higher compression ratio is required in diesel engine to ignite the fuel that leads to better efficiency. For complete combustion inside the cylinder it is important to ensure the clean air flow with free of debris and as cool as possible. In this manner, modification of intake valve arrangements is taken in to consideration importantly. In this paper, the intake valve arrangements are modified with newly designed valve mixer. It causes swirl flow of air through the intake port that mixing with the fuel followed by complete combustion. The use of valve mixer reduces the carbon sediment formation on valve fillet and its face area as the carbon particles gradually take place on it after certain running period. It therefore, helps to increase the valve lifetime. And at the same time it reduces the exhaust elements i.e. soot from the automobiles to a significant level.

• Applied Science and Convergence Technology
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• 제23권1호
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• pp.1-13
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• 2014

Semiconductor quantum structures are often characterized by their energy gaps which are modified by the quantum size effect. Energy levels in semiconductors can be realized by optical transitions within confined structures. Photoluminescence spectroscopy in magnetic fields at low temperatures has proved to be a powerful technique for investigating the electronic states of quantum semiconductor heterostructures and offers a complimentary tool to electrical transport studies. In this review, we examine comprehensive investigations of magneto-excitonic and Landau transitions in a large variety of undoped and doped quantum-well structures. Strong magnetic fields change the diamagnetic energy shift of free excitons from quadratic to linear in B in undoped single quantum well samples. Two-dimensional electron gas induced by modulation doping shows pronounce quantum oscillations in integer quantum Hall regime and discontinuous transition at ${\nu}=1$. Such discontinuous transition can be explained as the formation of spin waves or Skyrmions.

• 대한화학회지
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• 제66권5호
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• pp.341-348
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• 2022

In this work, radio frequency magnetron sputtering was used to deposit zinc selenide thin films on p-type silicon (100) wafers and glass substrates in a high vacuum chamber. Several surface characterization instruments were implemented to study the thin films. X-ray photoelectron spectroscopy results revealed that oxidized Zn bound to Se (Zn-Se) at 1022.7 ± 0.1 eV becomes the dominant oxidized species when Se concentration exceeds 70%. Scanning electron microscopy coupled with energy dispersive spectroscopy showed that incorporating Se in Zn thin films will lead to formation of ZnSe grains on the surface. Contact angle measurements indicated that ZnSe-60 exhibited the lowest total surface free energy value of 24.94 mN/m. Lastly, ultraviolet-visible spectrophotometry and ultraviolet photoelectron spectroscopy data evinced that the energy band gap gradually increases with increasing Se concentration with ZnSe-70 having the highest work function value of 4.91 eV.

• 한국식품과학회지
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• 제8권1호
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• pp.47-52
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• 1976

Aflatoxin이 함유된 TGY 액체배지(培地)에서 Bacillus megaterium NRRL B-1368 균주를 배양시 공시균(供試菌)의 생육저해(生育沮害), 형태적(形態的) 변화 및 정상(正常)배지에서의 생육회복(生育回復)과정을 조사하였다. Crude aflatoxin $(B_1\;22.7%,\;B_2\;1.6%,\;G_1\;3.6%,\;G_2\;0.2%)$의 농도 $20\;{\mu}g/ml$ 이상에서는 공시균(供試菌)의 생육(生育)이 완전히 억제(抑制)되었고 격막(隔膜)이 형성되지 않아 기형적(畸形的)으로 신장(伸長)하는 세포분렬의 장해현상을 보였다. 이들 기형(畸形)세포를 정상(正常)배지에서 다시 배양하면 격막이 형성되면서 정상(正常)세포로 분렬, 증식되었다. 따라서 aflatoxin은 세균의 격막형성에 관계하는 mesosome의 기능(機能)에 영향을 미치는 것으로 추론(推論)되었다.

• Journal of Microbiology
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• 제37권2호
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• pp.73-79
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• 1999

Pseudomonas sp. NGK1, isolated by naphthalene enrichment culture technique, is capable of degrading anthracene as a sole source of carbon and energy. The organism degraded anthracene through the intermediate formation of 1,2-dihydroxyanthracene, 2-hydroxy-3-naphthoic acid, salicylate, and catechol. The intermediates were isolated and characterized by TLC, spectrophotometry, and HPLC analysis. The cell free extract of anthracene-grown cells showed activities of anthracene dioxygenase, 2-hydroxy-3-naphthylaldehyde dehydrogenae, 2-hydroxy-3-naphthoate hydroxylase, salicylate hydroxylase and catechol 2,3-dioxygenase. The formed catechol as a metabolite is degraded through meta-cleavage with the formation of ${\alpha}$-hydroxymuconic semi-aldehyde.

• Journal of Welding and Joining
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• 제16권4호
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• pp.117-124
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• 1998

During the reflow process in SMT, the molten solder has been observed to move upward and solidify along the gullwing lead, which is called the wicking phenomenon. In this paper, possible causes of the wicking are investigated, and its effects on the solder joint profile are quantitatively estimated by introducing the wicking constant. The free energy reduction by intermetallic formation between the copper and tin seems to be the major source of wicking action. The joint profiles of the gullwing lead are calculated using the previous finite element formulation incorporated with the wicking constant. The calculated results show reasonably good agreements with the experimental data when the wicking effects are considered.

• 대한화학회지
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• 제13권1호
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• pp.5-8
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• 1969

Acid dissociation constants and chelate stability constants of 8-hydroxyquinoline-5-sulfonic acid have been determined for divalent metal ions. Co (Ⅱ), Ni (Ⅱ) and Zn (Ⅱ) by means of the Calvin-Bjerrum technique at the various temperatures. The standard free energy changes for the reactions at $20^{\circ}$, $30^{\circ}$, $40^{\circ}$and $50^{\circ}C$ were calculated, and the corresponding values of ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ applying over this temperature range are reported. The results are interpreted on the basis of current theories of metal chelate formation in aqueous solution.

• 반도체디스플레이기술학회지
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• 제10권2호
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• pp.45-48
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• 2011

In this paper, vacancy clustering formation and diffusion of germanium substrate was studied. The analysis method was adopted Monte Carlo method. At temperatures higher than melting point, fewer clusters formed, but there was less variation in the number of clusters than at lower temperatures, as the time increased. Equilibrium diffusivities in the clustering region were $10^2$ lower than those of free vacancies in the initial stage of kinetic lattice Monte Carlo simulations. They were expressed according to three temperature regimes: at temperatures above 1,100 K, at temperatures of 1,100-900 K, and at temperatures below 900 K. The effective mean migration energy, 1.1 eV, closely coincided with that of the 1.0-1.2 eV in experiments.