• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.473-474
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• 2010

This high pressure synchrotron X-ray diffraction study examined the change of bulk modulus of C-S-H(I), core material creating strength in alkali-activated slag cement as well as structural model of C-S-H, mainly attributed to Al-substitution for Si, which occurs at the bridging tetrahedral sites in dreierketten silicate chains in the nanostructure of C-S-H(I). This study presents that Al-substitution in C-S-H(I) does not affect the bulk modulus of C-S-H(I), which is surprising because many researchers have expected that Al-substitution should induce some critical change in mechanical properties of C-S-H(I).

• Journal of IKEEE
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• v.24 no.2
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• pp.619-625
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• 2020

In this paper, we propose a TS-DMOSFET(Trench Shielded DMOSFET) structure in which P+ shielding region is formed in a deeper region than C-DMOSFET(Conventional DMOSFET) and S-DMOSFET(Shielded DMOSFET). Using TCAD simulation to compare the static characteristics of TS-DMOSFET with C- and S-DMOSFET. As for the structure proposed, the doping is followed by the source trench process. Despite the fact that it is a SiC material, this allows it to form a P+ shielding region in a deep area. Followed by completely suppressing the reach-through effect. As a result, when the breakdown voltage of the three structures is 3.3kV, the Ron of TS-DMOSFET is 9.7mΩ㎠. Thus, it is 68% and 54% smaller than the Ron of C-DMOSFET and S-DMOSFET respectively.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.585-593
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• 2007

This paper presents a model for durability evaluation of concrete structures exposed to marine environment, considering mainly a build-up of surface chloride $(C_s)$ as well as diffusion coefficient (D) and chloride threshold level $(C_{lim})$. In this study, time dependency of $C_s$ and D were extensively studied for more accurate evaluation of service life of concrete structures. An analytical solution to the Fick's second law was presented for prediction of chloride ingress for time varying $C_s$. For the time varying $C_s$, a refined model using a logarithm function for time dependent $C_s$ was proposed by the regression analysis, and averaging integrated values of the D with time over exposed duration were calculated and then used for prediction of the chloride ingress to consider time dependency of D. Durability design was also carried out for railway concrete structures exposed to marine environment to ensure 100 years of service life by using the proposed models along with the standard specification on durability in Korea. The proposed model was verified by the so-called performance-based durability design, which is widely used in Europe. Results show that the standard specification underestimates durability performances of concrete structures exposed to marine environment, so the cover depth design using current durability evaluation in the standard specifications is very much conservative. Therefore, it is found that utilizing proposed models considering time dependent characteristics of $C_s$ and D can evaluate service lift of concrete structures in marine environment more accurately.

• Journal of Life Science
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• v.10 no.3
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• pp.279-285
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• 2000

CRP (cyclic AMP receptor protein) regulate transcription of catabolite-sensitive genes in Escherichia coli. Wild-type and mutant CRP (S83G and S128A) proteins were used to measure the thermal stability and the temperature-dependent structural change by proteolytic digestion, UV spectrophotometer and CD spectrapolarimeter. The result indicated that wild-type CRP was more thermally stable than the mutant CRPs in the presence of cAMP. At a low temperature, wild-type CRP with cAMP was more sensitive to subtilisin than the mutant CRPs. At a high temperature, there was no difference of sensitivity to subtilisin among wild-type, S83G and S128A CRPs. CD spectra suggested that the secondary structure of CRP was destroyed partially at a high temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.18-21
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• 2000

진공 분위기에서 소성하여 ZnS 형광체를 제작하였다. ZnS 형광체는 소성온도가 $950^{\circ}C$ 이하인 경우 sphalerite 구조로 성장되었고, $1050^{\circ}C$ 이상인 경우 sphalerite 구조와 wurtize 구조의 공존이 확인되었다. Sphalerite 구조일 때 나타나는 460 nm를 중심으로 하는 발광 peak과 wurtize 구조일 때 나타나는 440 nm를 중심으로 하는 발광 peak은 ZnS 형광체 내에 형성된 $V_{Zn}$에 기인한다. Sphalerite 구조로 성장되었을 때 발광 스펙트럼에서 관측되는 528 nm를 중심으로 하는 발광 peak과 sphalerite와 wurtize 구조가 공존할 때 발광 스펙트럼에서 관측되는 515 nm를 중심으로 하는 발광 peak은 ZnS 형광체 내에 형성된 S의 결핍($V_s$) 준위로부터 가전자 띠로 복사 전이에 기인하는 것으로 설명된다.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.734-740
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• 1995

The primary and secondary structures of Xanthomonas palargonii 5S rRNA were determined. The higher order structure of the 5S rRNA was also analysed using several ribonucleases and chemical probes, such as ethylnitrourea, Pb2+, dimethylsulfate and diethyl pyrocarbonate. Ethylnitrourea was used for probing the phosphate groups involved in the tertiary interactions in the 5S rRNA. Nucleotides G72, A73, G75, A78, G98, G100 and A101 in unstable helical region d, nucleotides C36, C37, A39, and C41 in loop c, nucleotides A29 and G33 in stem C became resistant to ethylnitrourea modification in the presence of Mg2+. On the basis of findings from chemical and enzymatic studies, and also Pb2+-induced cleavages, it was concluded that region b-C and unstable helical region d may act as hinges in the folding of 5S rRNA.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.20 no.2
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• pp.39-45
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• 2016

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.90-96
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• 2018

In this study, the mechanical and micro-structural change of cement pastes incorporating Stainless-Steel Slag Argon Oxygen Decarburization Slag (STS-A) containing ${\gamma}-C_2S$ as a carbon capture materials were investigated with carbonation curing condition. ${\gamma}-C_2S$ is non-hydraulic, therefore does not react with water. But ${\gamma}-C_2S$ has a reactivity under carbonation curing condition with water. The reaction products fill up the pore in pastes. The microstructure of STS-A blended cement pastes could be densified by this reaction. The pore structure of cement pastes incorporating STS-A was measured using mercury intrusion porosimetry (MIP) after carbonation curing ($CO_2$ concentration is about 5%). Also the fractal characteristics were investigated for the effect of carbonation curing on the micro-structural change of paste specimens. From the results, the compressive strength of carbonated specimens incorporating STS-A increased and pore-structure of carbonated paste is more complicated.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.121-129
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• 1997

The five species of genus Cobitis from Korea were investigated by electron microscopes to clarify the adhesive membranes on zona radiata. In the late vitellogenic stage the adhesive membranes could be classified into two form as follows: 1) granular form of Cobitis lutheri, C. striata, C. sinensis, and C. sinensis-longicorpus, 2) villous form of C. melanoleuca. Although C. lutheri, C. striata, C. sinensis, and C. sinensis-longicorpus possessed the same granular form, it was evident that fine structure of the zona radiata varied according to species. The adhesive membranes and fine structures of zona radiata in Cobitis showed a species specificity closely related to their habitats and spawning properties.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.261-274
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• 2000

The o/w emulsions were prepared with saccharide surfactants which were sucrose monostearate(S160), sucrose distearate(S110), and POE(20) methyl glucose stearate(SSE20). And for emulsion the oils used were n-hydocarbon, squalane(SQ), liquid paraffin(LP), octylpalmitate(OP), octylstearate(OS), alkyl benzoate(AB), isostearyl benzoate(ISB). The structures of o/w emulsion droplet were investigated by laser light scattering and the fractal dimensions were calculated from light intensity curves. Increasing of concentration, chain length, and nonpolarity of oils, fractal dimensions of emulsion droplets were found greater. In general fiactal dimensions were varied from 1.7 to 2.8 and its structures were fractal But the fractal dimensions of octadecane( $C_{18}$), 50, and LP emulsified with S110 and S160 were varied from 3.0 to 3.2 and its structures were more dense. The overall fractal dimensions of S110 and S160 were varied from 2.1 to 2.6, that of SSE20 were varied from 1.5 to 2.1. So it was found that the structures of SSE20 system were less compact than that of S110 and S 160 system, because the hindrance effect of polyoxyehtylene group of SSE20 was stronger than that of sucrose of S160. The strucures of emulsion droplets changed according to the nature of emulsifiers and to compositions of oil substances which they contained, and the structures were found similar when the hydophilic moiety of emulsifiers was same.