• Journal of the Korean Vacuum Society
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• v.20 no.5
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• pp.361-366
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• 2011

An in-situ, real-time monitoring of GaN epilayers grown by low pressure metalorganic chemical vapor deposition system modified for spectral reflectance was performed. Reflectance spectrums from 190~861 nm were observed using p-polarized light with incident angle of $75^{\circ}$. All reflectance spectrums showed interference oscillation caused by multiple reflection within GaN epilayers, and the spectrum from GaN with low crystalline quality showed weak reflectance intensity and much low amplitude of the oscillation because many defects in GaN resulted in light scattering and absorption. Signal variation of reflected light which was selected around strong constructive wavelength range was also observed during $NH_3$ supplying and $NH_3$ cut-off. There was no significant change in signal intensity when $NH_3$ cut-off for 10 sec, but it showed higher intensity when $NH_3$ was cut off for over 30 sec and its intensity kept unchanged. This result indicates that GaN surface was N-terminated during $NH_3$ supplying but Ga-terminated during $NH_3$ cut-off because of high nitrogen equilibrium vapor pressure of GaN, and metallic Ga-terminated surface caused slightly higher reflectance intensity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.3
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• pp.47-66
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• 1999

We have tried to measure the anti-dandruff effect of the several kinds of formulations by determining the MIC values of the P. ovale which was determined by resazurin(alarmar Blue$^{TM}$). To get high reproducibility, it was suggested that about 2.6$\times$10$^{5}$ cfu/$m\ell$ of P ovate should be incubated with alarmar Blue$^{TM}$, optimum dilution ratio between alarmar Blue$^{TM}$ and PBS buffer should be 1:1 -1:4, and optimum incubation time should be 16 ~ 24 hours. Even though 1:1 diluted alarmar Blue$^{TM}$ was incubated with P ovale, the metabolic activity of if ovule was not inhibited by alarmar BlueTM. The Minimum Inhibitory Concentration(MIC) values of several kinds of anti-dandruff formulation which were the mixture system between Zinc pyrithione and Climbazole make it possible to determine the optimal anti-dandruff formulation, which show similar results with that of microscopic MIC determination and that of SDDM(Skin-Disk Diffusion Method). It is expected that the anti-dandruff test method which uses alarmar Blue$^{TM}$ could be used as an effective in vitro test method because it was not so much affected by the turbidity of the broth and samples, and it can afford the MIC values of many samples within relatively short time by using microplate reader.te reader.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.681-688
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• 2009

To better delineate the changes in corticospinal excitability when older adults are asked to observe and/or imagine actions, 22 right-handed older adults without neurological abnormalities were included in this study. The amplitude and latency of motor evoked potentials (MEPs) by transcranial magnetic stimulation were recorded in the abductor pollicis brevis of the dominant hand during passive observation/imagery/active observation of slow/fast action of abduction of right thumb and also at resting state. Thus, active observation showed better changes than passive, but slow and fast action revealed no difference at all.

• Applied Microscopy
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• v.31 no.1
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• pp.1-8
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• 2001

The morphological features of neuronal dendritic spines are changed their shapes, sizes and density in response to physiological or pathological conditions . Therefore, exact analysis of spines warrants understanding of neuronal function. The size of the spine is at the borderline of resolution with light microscopy. High voltage electron microscopy Provide excellent resolution of the spines with proper stain techniques thanks to its higher resolution and penetration power. We evaluated more effective staining method for observing dendritic spines after labeling Purkinje cells with anti-calbindin 28 kD immunohistochemistry or Golgi staining methods. 4 fm thickness sections were observed with high voltage electron microscopy and some morphometric analyses were performed. Both Golgi staining and immunohistochemistry revealed the detail structures of the Purkinje cell such as soma, dendrites, and dendritic spines. High voltage electron micrographs with Golgi staining provide more precise morphology and are easy to measure. Average density of spine is $24.5{\pm}3.6/10{\mu}m$ and its length is $1.12{\pm}0.22{\mu}m$. For quantitative analysis of the spines, high voltage electron, micrographs with Golgi staining are more effective. This preliminary result is expected to be useful for further study of spine plasticity in various conditions.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.63-67
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• 1997

환원확산법은 저렴한 Nd 산화물을 환원제를 이용하여 환원시키고 환원된 Nd가 Fe, FeB와 확산하여 주상인 Nd$_2$Fe14B가 만들어지는 공정으로 환원제로 사용된 CaO나 미반응 Ca 및 잔존 산소함량을 조절하는데 어려움이 있어 아직까지는 상업되지 못하고 있는 실정이다. 본 연구에서는 환원확산법을 이용하여 Nd-Fe-B계 영구자석에 사용될 미세분말을 제조하고 그 자기적 특성을 관찰하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.3
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• pp.468-473
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• 1998

Sol-gel법을 이용하여 PbTiO3에 La을 10mol% 도핑한 박막을 bare Si(100)-wafer 위에 스핀 코팅법을 이용하여 제조하였다. 제조된 박막의 열처리 온도에 따른 결정화 거동을 살펴보고, 씨앗층(seeding layer)을 도입하여 박막의 미세구조 및 배향성을 SEM과 XRD로 관찰하였다. 씨앗층없이 일반적으로 제조된 박막의 경우는 우선 배향성을 나타내지 않았으나, 씨앗층을 도입한 경우에는 씨앗층의 두께 및 열처리 시간에 따라 막의 배향성이 달라졌다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.898-906
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• 1991

본 연구에서는 입경부식법에 의한 재질열화 평가법의 표준화에 연구목적을 두 고, 고온부재의 열화에 따른 조직의 특성변화를 관찰하였다.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.74-81
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• 2000

Purpose: The purpose of this study was to develop in vivo dosimetries using both chromosomal aberrations and micronuclei in mice to assess biological effects of radiations. Materials and Methods: Five each mice were irradiated with 0, 1, 2, 3, 4, 5, 10 Gy of Cs-137 gamma-rays. We scored numbers of chromosomal aberrations in metaphase spreads and numbers of micronuclei in bone marrow smears under light microscope, and obtained the dose-response relationships. We also examined the relationship between the two dose-response curves. Results: The frequency of both chromosomal aberrations and micronuclei increased with dose, in a linear-quadratic manner The delta, beta, and alpha coefficients were 0.0176, 0.0324, and 0.0567 for metaphase analysis (r=1.0, p<0.001) and 0.0019, 0.0073, and 0.0506 for micronuclei assay (r=1.0, p<0.001). The frequency of chromosomal aberrations and micronuclei in different radiation doses was significantly correlated (r=0.99, p<0.01). Conclusion: In vivo dosimetry using either metaphase analysis or micronucleus assay was feasible in mice. These methods could be useful to evaluate biological effects of radiation.

• Journal of Korea Technology Innovation Society
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• v.15 no.2
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• pp.262-276
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• 2012

Transactions activation of intangible assets has become became a key factor for corporate survival and successful business in the knowledge economy. Thus, demand in correctly valuating technology has increased. The market approach is the reliable method because of the premise that the market value of an asset is directly related to the prices of comparable, competitive ones. However, it can be practically impossible in many cases because it is hard to find identical transactions, which are generally closely guarded business secrets. As a result, most of technology valuation is conducted by the income approach and this approach is used to derive estimates for such unobserved variables. In September 2011, the Ministry of Knowledge Economy enacted a law for operational guideline standards for technology valuation to encourage the domestic technology valuation market. The enforcement recommended that the market approach have precedence over other approaches. If this approach cannot be applied, then the valuator should writing that he used other approaches. In practice, it is hard to know whether or not information about comparable transactions exists. The proposed process provides valuators to assess suitability for practical use of market approach through the observation process of technology transactions information. At the same time, it offers them the opportunity to gain validity when using other approaches.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.331-339
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• 1998

The purpose of this study was to investigate the applicability of periodic acid thiocarbohy-drazide silver proteinate, physical development (PA-TCH-SP, -PD) stain to the seminiferous tubules for the ultrastructural studies of Sertoli cell column and Sertoli cell processes. In the Sertoli cell cloumn and Sertoli cell processes, high concentration of the reactive granules were observed under transmission electronmicroscope (TEM) after PA-TCH-SP-PD stain. Also some reactive granules were seen in the spermatogonium cytoplasm, clearly. These reactive granules specifically stained with PA-TCH-SP, -PD make the Sertoli cell column, Sertoli cell processes and spermatogonium cytoplasm easy to distinguish from nucleus of the germ cells, spermatocyte, spermatid and residual body which did not contain the reactive granules. This result indicates that the PA-TCH-SP, -PD stain is superior to other traditional electronic double stain methods for the ultrastructural studies of Sertoli cell.