• 유통과학연구
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• 제16권7호
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• pp.47-56
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• 2018

Purpose - This study aims to not only investigate spatial pattern of immigrants' residence and crime occurrences in South Korea, but shed light on how geographic distribution of immigrants and immigrant segregation affect crime rates. Research design, data, and methodology - Th unit of analysis is Si-Gun-Gu municipal level entities of South Korea. The crime data was obtained by Korea National Police Agency and two major types(violence and property) of crime were measured. Most demographic, social, and economic variables were derived from Korean Census Data in 2015. In order to examine spatial patterns of immigrants' distribution and crime rates in South Korea, the present study utilized GIS mapping technique and Exploratory Spatial Data Analysis(ESDA) tools. The causal linkage was investigated by a series of regression models using STATA. Results - Spatial inequality between urban metropolitan vs rural areas was visualized by mapping. Assuming large Moran's I value, spatial autocorrelation appeared to be quite strong. Several neighborhood characteristics such as residential stability and economic prosperity were found to be important factors leading to crime rate change. Residential distribution and segregation for immigrants were negatively significant in the regression models. Conclusions - Unlike the traditional arguments of social disorganization theory, immigrant segregation appeared to reduce violent crime rate and the high proportion of immigrants also turned out to be a crime prevention factor.

• 한국재료학회지
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• 제31권7호
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• pp.409-419
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• 2021

The effect of solidification rate on micro-segregation in investment casting of IN738LC superalloy was studied. In Ni-based superalloys, the micro-segregation of solute atoms is formed due to limited diffusion during cast and solidification. The microstructure of cast Ni-based superalloys is largely divided into dendrite core of initial solidification and interdendrite of final solidification. In particular, mosaic shaped eutectic γ/γ' and carbides are formed in the interdendrite of the final solidification region in some cases. The micro-segregation phenomena formed in regions of dendrite core and interdendrite including eutectic γ/γ' and carbides were analyzed using OM, SEM/EDS and micro Vickers hardness. As a result of analysis, the lack of (Cr, W) and the accumulation of Ti were measured in the eutectic γ/γ', and the accumulation of (Cr, Mo) and the lack of Ti were measured in the interdendrite between dendrite and eutectic. Carbides formed in interdendritic region were composed of (Ti, W, Mo, C). The segregation applied to each microstructure is mainly due to the formation of γ' with Ni₃(Al,Ti) composition. The Ni accumulation accompanied by Cr depletion, and the Ti accumulated in the eutectic region as a γ' forming elements. The Mo tends to diffuse out from the dendrite core to the interdendrite, and the W diffuse out from the interdendrite to the dendrite core. Therefore, the accumulation of Mo in the interdendrite and the deficiency of W occur in the eutectic region located in the interdendrite. Heat treatment makes the degree of the micro-segregation decrease due to the diffusion during solid solution. This study could be applied to the heat treatment technology for the micro-segregation control in cast Ni-based superalloys.

• 미생물학회지
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• 제26권2호
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• pp.82-87
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• 1988

The genetic analysis and characterization of protoplast fusion hybrids between complementary auxotrophic mutants of Candida pseudotropicalis were carried out. Nuclear fusion appeared to occur in fusion hybrids (e.g., F15 and F33), as strongly suggested by isolation of recombinants after mitotic segregation of parental genetic markers. This was confirmed by KNA content, nuclear staining and comparison of survival rate to UV light. After keeping fusion hybrids for approximately one year, the frequency of spontaneous mitotic segregation was $3.0\times 10^{-4}$ - $8.1\times 10^{-4}$ while that of induced mitotic segregation was $1.4\times 10^{-3}$- $1.7\times 10^{-3}$. These results suggested that they maintained stable karyogamy state. It was also found that the production of $\beta$-D-galactosidase from F15, F33 and F158 was somewhat increased when compared with that from either auxotrophic parents or wild type.

• 소성∙가공
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• 제16권3호
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• pp.178-186
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• 2007

Rheo-forging process of aluminum alloy is suitable for large parts of net shape without defects and excellent mechanical properties in comparison with conventional die casting and forging process. To control the microstructure of the product with high mechanical properties in rheo-forming, solid fraction is required to prevent porosity and liquid segregation. Therefore, in rheo-forging process, die shape, pressure type and solid fraction are very important parameters. The defects such as porosity, liquid segregation and unfitting phenomena occur during rheo-forging process. To prevent these defects, mechanical properties and microstructure analysis of samples versus the change of pressure are carried out and the problem and its solutions are proposed. Also, the mechanical properties versus various pressures were compared with and without heat treatment. The alloys used for rheo-forming are A356 and 2024 aluminum alloy. The rheology material is fabricated by electromagnetic process with controlling current and stirring time.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.101-102
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• 2019

The use of high fluidity concrete has been added in recent construction work. In this study, we analyzed segregation resistance due to admixture substitution of the system high fluidity concrete that was hardened. The research results show that the resistance to segregation at the time of admixture replacement is improved. The best results were shown with a ternary system mixed like FA and BS.

• Journal of the Korean Statistical Society
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• 제6권2호
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• pp.167-177
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• 1977

유전적 질환이 있는 가계에서 출생하는 자녀중에서 유전적인 질환을 보유할 수 있는 확률을 예측하는 방법의 하나로서 우도추정치(likelihood estimator)를 사용하는 것은 분리분석(segregation analysis)에서 중요한 역할을 하고 있다. Elston과 Stewart(1971)는 이러한 분석방법의 일반적인 통계모형을 정립하였으며 필자(1974)와 Morton 등 (1974)은 complex segregation이 될 때에 분석되는 4가지의 통계모형을 주장하였다. 본 연구의 목적은 multiple ascertainment $\pi$가 존재하는 경우 분리확률모수(segregation parameter) $\theta$의 우도추정치를 구하고 둘째로 oligogenic case에 대한 이론적인 배경을 구명하고자 한다.

• Journal of Plant Biology
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• 제36권2호
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• pp.127-132
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• 1993

Self-incompatibility in Brassica campestris is controlled by multi-allele system in a single genetic locus, the S locus, and it is elucidated that S-glycoproteins are S gene products. In this experiments, we examined the genetic mode(pollen tube behavior and segregation of S-glycoprotein), characteristic of S-glycoproteins and DNA constitution within nuclear genome on S gene family that unexplained by single locus model, and investigated the segregation pattern of S-glycoproteins in bred F1 generation. By diallel cross among the 15 plants within one family the existence of three types of homozygotes and three types of heterozygotes were observed, and segregation of S-allele could not explained by single locus model. From the results of IEF-immunoblot analysis for non-segregated individual plant, the segregation pattern of S specific bands was corresponded with results of diallel cross except with one case(SaSa genotype). The molecular weight of 6 different S-genotype varied in near by 50 kD, and each genotype expressed with 2 or 3 bands. Specific bands in SaSa, SbSb, ScSc has almost similar molecular weight between them. Southern analysis of genomic DNA probed with S-glycoprotein cDNA for 6 different genotypes revealed that there are clear difference in polymorphism, multiple bands of hybridization, when restriction enzymes of EcoR I were used. It could be assumed that there are several sequences related to the S-glycoprotein structural genes within their nuclear genome. Therefore, we suggested the possibilities that S-allele system could be controlled by multi-locus, that dominance-recessive interactions could be explained by modifier gene or supressor gene based on the results of abnormal segregation of S-glycoprotein in bred F1. The F2 analyses are progressing in now.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.60-60
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• 2015

Nanosheets of graphene and related 2D materials have attracted much attention due to excellent physical, chemical and mechanical properties. Single-layer graphene (SLG) was first synthesized by Blakely et al in 1974 [1]. Following his achievements, we initiated the growth and characterization of graphene and h-BN on metal substrates using surface segregation and precipitation in 1980s [2,3]. There are three important steps for nanosheet growth; surface segregation of dopants, surface reaction for monolayer phase, and subsequent 3-D growth (surface precipitation). Surface phase transition was clearly demonstrated on C-doped Ni(111) by in situ XPS at elevated temperatures [4]. The growth mode was clarified by inelastic background analysis [5]. The surface segregation approach has been applied to C-doped Pt(111) and Pd(111), and controllable growth of SLG has been demonstrated successfully [6]. Recently we proposed a promising method for producing SLG fully covering an entire substrate using Ni films deposited on graphite substrates [7]. A universal method for layer counting has been proposed [8]. In this paper, we will focus on the effect of competitive surface-site occupation between carbon and other surface-active impurities on the graphene growth. It is known that S is a typical impurity of metals and the most surface-active element. The surface sites shall be occupied by S through surface segregation. In the case of Ni(110), it is confirmed by AES and STM that the available surface sites is nearly occupied by S with a centered $2{\times}2$ arrangement. When Ni(110) is doped with C, surface segregation of C may be interfered by surface active elements like S. In this case, nanoscopic characterization has discovered a preferred directional growth of SLG, exhibiting a square-like shape (Fig. 1). Also the detailed characterization methodologies for graphene and h-BN nanosheets, including AFM, STM, KPFM, AES, HIM and XPS shall be discussed.

• 한국지역지리학회지
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• 제13권5호
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• pp.477-494
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• 2007

본 논문은 부산시를 대상으로 1900년대 초(구한말)부터 현재에 이르기까지 거주지역의 불평등한 현상을 거주분화의 개념을 중심으로 사회공간적으로 분석한다. 부산은 1900년대 초 조선 전통사회의 성격을 이어받아 신분사회의 계층질서에 의한 거주선택의 제한으로 불평등한 거주공간이 형성되었다. 이후 일제에 의한 신시가지의 형성으로 기존의 한국인 거주지와 분리되는 현상을 경험하였으며 일본인과 한국인, 그리고 중국인 거주지역으로 구분되는 민족별 분화 현상도 나타났다. 해방과 한국전쟁 이후 급속하게 인구가 증가함으로써 새로운 빈민거주지역이 등장하였고 이는 이후에 전개될 거주지 분화의 주요 요인으로 작용하게 된다. 빈민지역의 문제를 해소하기 위해 1960년대부터 실시한 정책이주는 제도상의 결점으로 인하여 큰 효과를 보지 못하였다. 1990년 이후 주민의 사회경제적 지위는 주택선택에 영향을 주어 주택계층에 의한 거주지역분화를 가능하게 하였다. 중간주택계층보다는 상 하위 주택계층이 거주공간의 불평등한 분포에 큰 영향을 주었다. 맥락적이고 시계열적인 접근방법을 시도하여 거주공간의 사회공간적 불평등에 관한 인과성을 파악하려고 시도한 본 연구는 미래에 전개될 거주공간패턴을 예측하고 다른 도시들의 거주공간연구에 도움을 줄 것으로 예상된다.

• 한국주조공학회지
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• 제35권6호
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• pp.170-177
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• 2015

Segregation during solidification and homogenization during thermal exposure in GTD 111 were investigated. The microstructures of as-cast, standard heat-treated, and thermally exposed specimens were observed by SEM. A compositional analysis of each specimen was conducted by EDS. The dendrite core was enriched in W and Co, though lower levels of Ti and Ta were observed. An unexpected phase, in this case like the ${\eta}$ phase, was observed due to segregation near the ${\gamma}-{\gamma}^{\prime}$ eutectic in the standard heat-treated specimen. Segregation also induced microstructural evolution near the ${\gamma}-{\gamma}^{\prime}$ eutectic during the standard heat treatment. A quantitative analysis and microstructural observations showed that the thermal exposure at a high temperature enhanced the chemical homogeneity of the alloy.