• 한국재료학회지
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• 제13권11호
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• pp.756-760
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• 2003

Two dimensional computer simulations were conducted on percolative structure in which second phases with various short diameter were arranged in matrix phase. In case of prohibiting the overlap among the second phases, the maximum area fraction of second phase arranged in matrix was increased with higher short diameter. In case of allowing the overlap among the second phases, the critical area fraction was increased with higher short diameter and the total number of distributed second phase was decreased. This results represented that thickness variation of short diameter by grain growth on the production processes affect significantly forming the completion path.

• Communications for Statistical Applications and Methods
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• 제22권5호
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• pp.435-443
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• 2015

Two phase sampling design is useful to increase estimation efficiency using deep stratification, improved non-response adjustment and reduced coverage bias. The same sampling units are commonly used for the first and the second phases in complex two-phase sampling design. In this paper we consider a sampling scheme where the first phase sampling units are clusters and the second phase sampling units are list samples. Using selected clusters in first phase requires that we list up elements in the selected clusters from the first phase and then use the list as a secondary sampling frame for the second phase sampling design. Then we select second phase samples from the listed sampling frame. We suggest an estimator based on the complex two-phase sampling design with different sampling units of each phase. Also the estimated variances of the estimator obtained by using classic and replication variance methods are considered and compared using simulation studies. For real data analysis, 2010 Korea Farm Household Economy Survey (KFHES) and 2011 Korea Agriculture Survey (KAS) are used.

• 한국분말재료학회지
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• 제27권4호
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• pp.339-342
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• 2020

Since the interaction between the second-phase particle and grain boundary was theoretically explained by Zener and Smith in the late 1940s, the interaction of the second-phase particle and grain boundary on the microstructure is commonly referred to as Zener pinning. It is known as one of the main mechanisms that can retard grain growth during heat treatment of metallic and ceramic polycrystalline systems. Computer simulation techniques have been applied to the study of microstructure changes since the 1980s, and accordingly, the second-phase particle-grain boundary interaction has been simulated by various simulation techniques, and further diverse developments have been made for more realistic and accurate simulations. In this study, we explore the existing development patterns and discuss future possible development directions.

• 대한기계학회논문집
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• 제6권3호
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• pp.239-246
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• 1982

The effect of the second phase morphology on the fracture ductility of dual phase steel was studied by means of tensile tests carried out room temperature. In this case the second phase morphology is characterized by two kinds; one is the MEF microstructure in which martensite encapsulated islands of ferrite, the other is the FEM microstructure in which ferrite encapsulated islands of martensite. The fracture ductility is improved by variation of the second phase morphology, but is essentially uneffected in the range of high strength ratio (4.7). Also the variation of ductility is well understood according to the difficulty of cleavage crack formation of the ferrite grain and to the brittleness of the martensitic structure.

• 한국재료학회지
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• 제11권11호
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• pp.929-935
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• 2001

Two-dimensional computer simulations were conducted on percolation structure in which second phases of various aspect ratios were arranged in a lattice (matrix). The second phases were randomly arranged in an array with two different computational programs; one prohibiting an overlap among second phases and the other allowing the overlap. From the simulation prohibiting the overlap, it was predicted that a complete path was formed at less amounts of the second phase with higher aspect ratios. In the simulation allowing the overlap, a complete path throughout the array was formed by arranging the second phase of an aspect ratio of 1. 5, 20, 100 with less than 59%, 43%, 19%, 4% in the array, respectively.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2877-2883
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• 2010

The folding kinetics of $WT^*$ ubiquitin variant with valine to alanine mutation at sequence position 26 (HubWA) was studied by stopped-flow fluorescence spectroscopy. While unfolding kinetics showed a single exponential phase, refolding reaction showed three exponential phases. The semi-logarithmic plot of urea concentration vs. rate constant for the first phase showed v-shape pattern while the second phase showed v-shape with roll-over effect at low urea concentration. The rate constant and the amplitude of the third phase were constant throughout the urea concentrations, suggesting that this phase represents parallel process due to the configurational isomerization. Interestingly, the first and second phases appeared to be coupled since the amplitude of the second phase increased at the expense of the amplitude of the first phase in increasing urea concentrations. This observation together with the roll-over effect in the second folding phase indicates the presence of intermediate state during the folding reaction of HubWA. Quantitative analysis of Hub-WA folding kinetics indicated that this intermediate state is on the folding pathway. Folding kinetics measurement of a mutant HubWA with hydrophobic core residue mutation, Val to Ala at residue position 17, suggested that the intermediate state has significant amount of native interactions, supporting the interpretation that the intermediate is on the folding pathway. It is considered that HubWA is a useful model protein to study the contribution of residues to protein folding process using folding kinetics measurements in conjunction with protein engineering.

• 한국주조공학회지
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• 제19권1호
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• pp.84-90
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• 1999

In this study, CV cast iron was reverse transformed to produce harder second phase surrounding graphite nodules, and then the microstructure and related mechanical properties of the reverse transformed CV cast iron were investigated by using optical microscopy and by carrying out hardness, tension and impact test. The formation of hard second phase surrounding graphite nodules increased the hardness in CV cast iron. The marked increase in hardness was resulted from the formation of martensite surrounding graphite nodule. It is expected from these results that the formation of martensite surrounding graphite nodule would improve the wear resistance of CV cast iron. The formation of both martensite and pearlite surrounding graphite nodule improved the tensile properties. Impact properties were decreased with increasing the volume fraction of hard second phase. However, the reduced impact properties could be recovered through phase transformation of martensite into pearlite and sorbite by tempering.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.498-508
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• 2011

First phase section of line 9 which had been constructed by first private capitalization business of Seoul city was opened on July 24, 2009. There are 25 stations of 25.5km operation distance between Gaehwa and Sinnonhyeon, running regular and express trains on the same track. The number of daily passenger demand has risen to above 200thousand passengers with record above 90% of anticipatied transport demand in 2010. The construction of second phase section(Sinnonhyeon~Bohoon Hospital : 14km, 13 stations) is currently under construction for opening in 2016. This study aims to suggest optimal operating patterns taking into consideration theoretical operating headways for regular and express trains, demand of rolling stocks mainly analyzed on record of first phase demand of line 9 and anticipated transport demand of second phase basic plan.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.206-208
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• 2000

0.65 mol% MgO-doped LiNbO$_3$single crystals were grown by CZ method. The obtained single crystals were colorless and transparent. Noncritically phase-matched second harmonic generation (SHG) of 532-nm radiation from 1064-nm in MgO-doped LiNbO$_3$has been investigated by using pulsed Nd:YAG laser. The phase-matching temperature was room temperature. SHG conversion efficiencies were typically achieved higher than 50% at the phase-matching temperature with no photorefractive damage in the region of fundamental power density which was used in this experiment. The thermo-birefringence coefficient and the electro-birefringence coefficient of SHG were calculated from the temperature phase-matching profile with the electric field.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5477-5482
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• 2015

Background: This study aimed to investigate the incidence and risk factors for a prethrombotic state in patients with malignant tumors. Materials and Methods: Plasma d-dimer (D-D) in patients with malignant tumors was measured. Abnormal rates of D-D and possible risk factors like gender, age, type of tumor, and staging of tumor were analyzed. Results: Of 1,453 patients, 629 demonstrated plasma D-D abnormality (43.3%). The D-D abnormal rate of male patients (n=851, 43.5%) was not statistically significantly different from that for female patients (n=602, 43.0%) (p>0.05). D-D abnormal rate increased with age and was statistically significant among different age groups (p<0.05). Regarding staging of tumor, D-D abnormal rate in patients with phase I was 2.0%, 6.2% in phase II, 47.6% in phase III and 83.1% in phase IV, with statistically significant differences between phase III and II, as well as phase III and IV (p<0.01). Conclusions: A prethrombotic state was closely related to malignancy of tumors. The risk factors for a prethrombotic state include age and tumor stage.