• 소성∙가공
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• 제4권2호
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• pp.169-179
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• 1995

Static restoration mechanism during hot interrupted deformation of Cu-Zn alloy was studied in the temperature range from $550^{\circ}C$ to $750^{\circ}C$ and at a constant strain rate of 0.1/sec. At a given temperature, the hot interrupted deformations were performed with variation of interrupted time $t_i$ form 1 to 50 sec and of interrupted strain ${\varepsilon}_i$ from 0.15 to 0.90. From the analysis of the values of the critical strain of ${\varepsilon}_c$ for tje initiation of dynamic recrystallization and the peak strain of${\varepsilon}_p$, the relationship ${\varepsilon}_c{\fallingdotseq}0.7{\varepsilon}_p$ was obtained. It was clarified that the softening of the interrupted deformation was mainly the static recrystallization and the fractional softening(FS) which was over 30% mostly confirmed this result. The fractional softening of the interrupted time $t_i$ especially and pre-strain. The FS increased with increasing strain rate, interrupted time and pre-strain. The change of microstructures after hot deformation could be predicted by the FS. when the FS was 30~100%, static recrystallization was happened and grain growth was observed at the condition which was $750^{\circ}C$ deformation temperature, 0.45 prestrain and this condition's FS value was over 100%.

• Asian-Australasian Journal of Animal Sciences
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• 제33권2호
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• pp.197-202
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• 2020

Objective: The objective of this study was to identify environmental factors strongly associated with and to estimate genetic parameters of reproductive traits in Japanese Black heifers. Methods: Data included reproduction records of Japanese Black heifers born between 2004 and 2014. First service non-return rate (NRR) to 56 days from first to successful insemination (FS), number of services per conception (IN), age at first calving (AFC) and gestation length were analyzed with the use of the general linear model. Genetic parameters were estimated with the use of the univariate animal model of the residual maximum likelihood. Results: Averages of reproductive traits over eleven years were assessed, and the effects of farm, year, month, artificial insemination technician and interaction of farm×year on the traits were determined. Estimated heritability of FS was very low and that of AFC was higher than that of the other traits. A close genetic relation was observed among NRR, IN, and FS; however, their heritabilities were very low. AFC shows favorable genetic correlation with IN and FS. Conclusion: Low heritabilities of most reproductive traits in Japanese Black heifers are strongly influenced by farm management practices, and that large residual variances make genetic evaluation difficult. Among the reproductive traits, AFC is potentially more useful for genetic improvement of heifer reproductive traits because it has high heritability and favorable genetic correlations with IN and FS.

• Animal cells and systems
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• 제1권4호
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• pp.647-651
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• 1997

We have used a transient expression assay employing Drosophila S2 cells to study the transcriptional repression activity of a 27 amino acid residue-long repression domain FS1 which was generated by a frame-shift in a pair-rule gene, even-skipped of Drosophila melanogaster. In an attempt to define a minimal requirement for the repression activity, we constructed a series of truncation mutant forms of the FS1, fused to a heterologous GAL4 DNA-binding domain, and measured their activities. All of the mutant forms, including the GAL4-FS1 (5-23) which retains the smallest number (19) of amino acid residues of FS1, were found to repress an initiator, a minimal TATA-lacking promoter, in a GAL4-binding-site-dependent manner. These findings suggest that a 19 amino acid residue-long region, rich in proline and leucine residues, is a transcriptional repression domain and may interact with the general transcription machinery.

• 한국레이저가공학회지
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• 제17권4호
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• pp.7-13
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• 2014

In this work, the application of laser induced breakdown spectroscopy (LIBS) for the composition analysis of thin $Cu(In,Ga)Se_2$ (CIGS) solar cell films ($1-2{\mu}m$ thickness) is reported. For the ablation of CIGS films, femtosecond (fs) laser (wavelength = 343nm, pulse width = 500fs) and nanosecond (ns) laser (wavelength = 266nm, pulse width = 5ns) were used under atmospheric environment. The emission spectra were detected with an intensified charge coupled device (ICCD) spectrometer and multichannel CCD spectrometer for fs-LIBS and ns-LIBS, respectively. The calibration curves for fs-LIBS and ns-LIBS intensity ratios of Ga/Cu, In/Cu, and Ga/In were generated with respect to the concentration ratios measured by inductively coupled plasma optical emission spectrometry (ICP-OES).

• Geomechanics and Engineering
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• 제34권2호
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• pp.187-195
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• 2023

Intensive rainfall during the summer season in Korea has triggered numerous devastating landslides outside of downtown in mountainous areas. The 2D slope stability analysis that is generally used for cut slopes and embankments is inadequate to model slope failure in mountainous areas. This paper presents a new 3D slope stability formulation using the global sliding vector in the limit equilibrium method, and it uses an ellipsoidal slip surface for static and quasi-static analyses. The slip surface's flexibility of the ellipsoid shape gives a lower FS than the spherical failure shape in the Fellenius, Bishop, and Janbu's simplified methods. The increasing sub-columns of each column tend to increase the FS and converge to a steady value. The symmetrical geometric conditions of the convex turning corners do not indicate symmetrical failure of the surface in 3D analysis. Pseudo-static analysis shows that the horizontal seismic force decreases the FS and increases the mass volume at the critical failure state. The stability index takes the FS and corresponding sliding mass into consideration to assess the potential risk of slope failure in complex mountainous terrain. It is a valuable parameter for selecting a vulnerable area and evaluating the overall risk of slope failure.

• 대한환경공학회지
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• 제31권4호
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• pp.294-299
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• 2009

다이옥신의 대기 중 오염수준 및 거동을 조사하기 위해 청주시를 대상으로 3지점(공단, 주거/상업 및 농촌지역)에서 2008년 겨울철, 봄철, 및 여름철에 가스상과 입자상으로 나누어 시료를 채취하였다. 채취된 9개 시료의 대기 중 17개 다이옥신 이성질체의 농도범위는 0.73~2.48(평균 1.41) pg/$m^3$으로 검출되었으며, WHO 2005 TEQ 농도범위는 0.007~0.122(평균 0.051) pg TEQ/$m^3$으로 조사되었다. 이들 농도는 우리나라 다른 도시대기의 농도(불검출~2.149 pg TEQ/m3 )와 유사하거나 낮은 수준을 나타내었다. 대기 중 다이옥신은 대부분이 입자상태로 존재하고 있었으며(총 농도의 54~98%), 시료채취 시기나 지점에 관계없이 유사한 이 성질체 패턴을 나타내었다. 이성질체 분포 비교 및 통계적 해석결과, 청주시 대기 중 다이옥신은 특정한 오염원에 의한 영향은 미비하며 일반적인 연소공정에 의한 영향을 받고 있는 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권9호
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• pp.1349-1354
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• 2019

Objective: The objective of this study was to determine the best approach for handling missing records of first to successful insemination (FS) in Japanese Black heifers. Methods: Of a total of 2,367 records of heifers born between 2003 and 2015 used, 206 (8.7%) of open heifers were missing. Four penalty methods based on the number of inseminations were set as follows: C1, FS average according to the number of inseminations; C2, constant number of days, 359; C3, maximum number of FS days to each insemination; and C4, average of FS at the last insemination and FS of C2. C5 was generated by adding a constant number (21 d) to the highest number of FS days in each contemporary group. The bootstrap method was used to compare among the 5 methods in terms of bias, mean squared error (MSE) and coefficient of correlation between estimated breeding value (EBV) of non-censored data and censored data. Three percentages (5%, 10%, and 15%) were investigated using the random censoring scheme. The univariate animal model was used to conduct genetic analysis. Results: Heritability of FS in non-censored data was $0.012{\pm}0.016$, slightly lower than the average estimate from the five penalty methods. C1, C2, and C3 showed lower standard errors of estimated heritability but demonstrated inconsistent results for different percentages of missing records. C4 showed moderate standard errors but more stable ones for all percentages of the missing records, whereas C5 showed the highest standard errors compared with noncensored data. The MSE in C4 heritability was $0.633{\times}10^{-4}$, $0.879{\times}10^{-4}$, $0.876{\times}10^{-4}$ and $0.866{\times}10^{-4}$ for 5%, 8.7%, 10%, and 15%, respectively, of the missing records. Thus, C4 showed the lowest and the most stable MSE of heritability; the coefficient of correlation for EBV was 0.88; 0.93 and 0.90 for heifer, sire and dam, respectively. Conclusion: C4 demonstrated the highest positive correlation with the non-censored data set and was consistent within different percentages of the missing records. We concluded that C4 was the best penalty method for missing records due to the stable value of estimated parameters and the highest coefficient of correlation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권3호
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• pp.201-206
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• 2004

Vascular endothelial growth factor (VEGF), plays a key role in angiogenesis. Many endogenous factors can affect angiogenesis in endothelial cells. VEGF is known to be a strong migration, sprouting, survival, and proliferation factor for endothelial cells during angiogenesis in endothelial cells. Searching for novel genes involved in VEGF signaling during angiogenesis, we carried out differential display polymerase chain reaction on RNA from VEGF-stimulated human umbilical vein endothelial cells (HUVECs). In this study, follistatin (FS) differentially expressed in VEGF-treated HUVECs, compared with controls. Addition of VEGF (10ng/L) produced an approximately 11.8-fold increase of FS mRNA. F5 or VEGF produced approximately 1.8- or 2.9-fold increases, respectively, in matrix metalloproteinase-2 (MMP-2) secretion for 12h, compared to the addition of a control buffer. We suggest that VEGF may affect the angiogenic effect of HUVECs, through a combination of the direct effects of VEGF itself, and the indirect effects mediated via induction of FS in vitro.

• 생명과학회지
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• 제20권12호
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• pp.1872-1881
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• 2010

본 연구에서는 대두(FS)와 아가콩의 발효추출물(FYA)의 항암활성 기전을 확인하기 위해 AGS 인체위암세포의 증식에 미치는 영향을 조사하였다. AGS 세포에서 FS 및 FYA 처리로 인하여 암세포의 증식이 처리 농도 의존적으로 강하게 억제하였고, apoptosis 유발을 의미하는 세포의 전반적인 형태 및 핵의 변형 또한 동반하였다. 또한 세포주기 분석을 통하여 이 현상이 apoptosis 유도에 의한 것임을 확인하였다. AGS 세포에 처리된 FS 및 FYA는 pro-apoptotic factor인 Bax의 발현 증가를 통한 intrinsic pathway나, death receptor 관련 유전자의 발현 증가를 통한 extrinsic pathway를 활성화시키며, 더 나아가서 IAP family인자의 발현 억제 및 caspases의 활성 증가를 일으켜 apoptosis를 유발시키는 것을 유추할 수 있었는데, 이러한 효과들은 FS보다 FYA에서 더욱더 탁월하였다. 이는 향후 아가콩 발효추출물이 항암치료를 위한 적용 가능성이 매우 우수함을 제시하여 주는 결과이다.

• 한국전기전자재료학회논문지
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• 제29권1호
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• pp.30-34
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• 2016

In this paper, we report that selective etching on N-polar face by EC (electro-chemical)-etching effect on the reduction of bowing and strain of FS (free-standing)-GaN substrates. We applied the EC-etching to concave and convex type of FS-GaN substrates. After the EC-etching for FS-GaN, nano porous structure was formed on N-polar face of concave and convex type of FS-GaN. Consequently, the bowing in the convex type of FS-GaN substrate was decreased but the bowing in the concave type of FS-GaN substrate was increased. Furthermore, the FWHM (full width at half maximum) of (1 0 2) reflection for the convex type of FS-GaN was significantly decreased from 601 to 259 arcsec. In the case, we confirmed that the EC-etching method was very effective to reduce the bowing in the convex type of FS-GaN and the compressive stress in N-polar face of convex type of FS-GaN was fully released by Raman measurement.