• 제목/요약/키워드: major elements

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알루미늄 주조/단조 공정에서 주조조직 제어에 관한 연구 (A Study on the Control of Cast Microstructure in the Aluminum Casting/Forging Process)

  • 배원병;강정윤;이영석;이성모;홍창호
    • 한국정밀공학회지
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    • 제16권9호
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    • pp.41-47
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    • 1999
  • The scale of dendritic structure of a cast preform plays a key role in determining the mechanical properties of cast/forged products. In this study, casting experiments are carried out to reduce dendrite arm spacing (DAS) to smaller than 20 ${\mu}$m by increasing cooling rate of the mold and then to spheriodize dendritic structures by addition of alloying elements such as Zr and Ti-B. From the casting experiments, appropriate casting conditions for producing the cast preform of a motorcycle connecting rod are obtained. To obtain fine microstructures of the cast preform, mold temperature must set to be low whilst cooling rate being high. When cooling rate is 10 $^{\circ}C$/s, the size of DAS is 17.4 ${\mu}$m. And the degree of spheriodization of a grain in the cast preform is described by aspect ratio, which is defined as the ratio of major and minor radii of an elliptical grain. When 0.5% Zr and 0.24 % Ti+B are added to the molten aluminum alloy, the best aspect-ratio 0.75 is obtained. After forging the cast preform of a motorcycle connecting rod, the microstructure and mechanical properties of the cast preform are compared with those of the cast/forged product. Cast/forged products are superior in microstructure and in mechanical properties such as ultimate strength, elongation, and hardness.

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DiSC Behavioral Types of Freshmen at the Clinical Laboratory Science Department in D College

  • Noh, Eun Kyung;Lee, Sun Kyung
    • 대한임상검사과학회지
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    • 제46권2호
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    • pp.54-58
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    • 2014
  • This study aims to understand some related types (to DiSC behavioral ones) through an analysis about DiSC behavioral types of freshmen at the clinical pathology department in the University. In order to do that, a total of 34 male and female students were surveyed. General characteristics and DiSC behavioral types for the targeted students were analyzed for frequency and percentage. For the frequency, the Chi-square test was performed and the level of significance was set to p<0.05. For the elements to select the university at general characteristics from the result of this study, 21 students were found to have selected the university voluntarily (61.8%). For the information about the clinical pathology department, 14 students were found to be informed through media (41.2%) and 7 students were informed through their parents (20.6%). For the DiSC behavioral types of the students majoring in clinical pathology, 18 students were found to be I type (53.0%), 8 students were C type (23.5%), 5 students were S type (14.7%) and 3 students were D type (8.8%). The relevance between general characteristics and DiSC behavioral type were found to be insignificant. As this study is aimed, there is no significant relevance between general characteristics and DiSC behavioral types, but through an understanding of characteristics of the students majoring in the clinical pathology, helping freshmen who are taking their first steps to adapt themselves to a new environment by diagnosing and understanding their behavioral types, understanding behavioral styles of those four types and guiding them in a positive direction, the method should be considered to raise their satisfaction about the major.

고흥 미복산 부근에 분포하는 심성암류의 암석지구화학과 금함량 (Lithogeochemistry and Gold Content of Plutonic)

  • 윤정한
    • 자원환경지질
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    • 제32권6호
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    • pp.585-597
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    • 1999
  • Plutomic rocks of the Mabogsan, located in the southestern part of the Koheung Eup are composed of granite gneiss, diorite, biotite grantie and granophyre. On the basis of Rb-Ba-Sr diagram, the diorires are plotted from granodiorite to quartz diortie, the biotite granites from granodiortie to anomalous granite and the granophyres in normal granite filed. The plutonic rocks tend to show the I-type characteristics in terns of ACF diagram, $K_2O-Na_2O$ diagram and $Al_2O_3/Na_2O+K_2O+CaO$ diafram, while have values of ilmenite series in magnetic subseptibility. The plutons could have formed in the tectonic environment of VAG+COLG+ORG based on the silica vs. trace element diagrams. Gold contents with major and trace elements have been determined for 21 granophyres, 13 biotite granites and 4 diorites are; (1) for the diorite, the rangs is 0.508~1.73 ppb with an average of 0.5ppb;(2) for the biotite granites, the range is 0.449~13.5ppb with an average of 3 ppb;(3)for the granphyres, the range is 0.508~23.1ppb with an average of 4.5ppb. The gold content of the studied plutons tends to increase from mafic to felsic rocks. Gold contents tend to show positive correlations with those of Ag and Zn, negative correlations with those of As, Ba and Rb. The copper contents of the plutons are comparatively high. Average copper contents of diorite, biotite granite and granophyre are 710ppm, 587ppm and 484ppm, respectively. The copper contents of the plutons tend to have good correlations with those of Ag, Bi and Pb.

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서울시 도로변의 빗물받이에서 체취한 하수슬러지의 중금속 오염 평가 (The Assesment of Heavy metal Pollution in Sewage Sludeges from Gully Pots Alongside Some Main Roads in Seoul, Korea)

  • 이평구
    • 자원환경지질
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    • 제32권6호
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    • pp.633-644
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    • 1999
  • Gully pot is a part of urban darainage system to butter the runoff water fluxes from road to rivers and to minimize environmental pollution by prevending over the surrounding area. A series of studies have been carried out concerning the physicochemical characteristics of the sewage sludge sediments sttling down in such a gully pot in order to over to evaluate the contamination for heavy metals such as pb, Zn, Cu and Cd. The roadside soil and sewage sludge samples from gully pots were characterized by XRD analyses and sequential extraction : Zn 2595.7$\mu$g/g; Cd9.8$\mu$/g; Cu602.5$\mu$g/g; Pb260.0$\mu$g/g),because of a long-term accumulation of vehicle- and industrial-related pollutants. Mean Zn concentration in Yeouido (3873$\mu$g/g) and Junggu(3262$\mu$g/g)areas are 4-5 times higher than those in Dobonggu area, suggesting that Zn may be derived from automobile traffic (including the rubber of automobile tires). The mean concentrations of Cu and Cr are very significantly high in Junggu and Gurogu areas, possibly due to the industrial activities in these areas. The low Pb levels throughtotut the whole study areas in Seoul can be accounted for the use of unleaded gasoline since 1987. Sequential extraction experiments illustrate that a major part of Zn is bound to FII and FIII, representing about 88% of the total Zn concentration. Fraction IV, related to orgnic matter, is mostly significant for Cu accounting for 60% of the total Cu, and FII is next in importance. The main carriers of Pb are the fractions III, II and FIV, and in that order. The behavior of Cd is quite different from other elements (Zn, Cu, Pb), and most of the Cd is associated with FV. Changes in the physicochemical environments (such as acidification) may result in severe environmental pollution of surface water and rivers with respect to heavy metals (especially Zn and Cu).

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방송드라마의 체계적 제작 시스템에 관한 연구 (A Study on the Systematic TV Drama Production System)

  • 배진아
    • 게임&엔터테인먼트 논문지
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    • 제2권2호
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    • pp.75-84
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    • 2006
  • 방송 드라마는 대중적 인기 및 부가가치 창출의 차원에서 다른 어떤 장르의 프로그램보다 주목받는 방송영상 콘텐츠이다. 최근 들어 대규모 독립제작사의 등장 등 외부 요인으로 인하여 드라마 제작 시스템을 제대로 갖추어 보고자 하는 노력이 일부 있었으나, 아직까지 드라마 제작을 위한 체계화된 시스템은 갖추어지지 않은 상황이다 본 연구는 드라마 제작 현장의 전문가들과의 심층인터뷰를 통해서, 국내 방송3사의 드라마 제작 관행 및 시스템에 대해 분석하였다. 분석 결과 국내 드라마 제작 시스템은 소규모 프로그램 제작에 적합한 프로듀서-디렉터 시스템이었으며, 부가수익 창출을 위한 노력이 제작 전 단계에서부터 체계적으로 이루어지지 않고 있었다. 방송사가 드라마를 통해서 경쟁력을 확보하기 위해서는 전문 프로듀서 제도를 도입하고, 제작 요소를 체계적으로 관리하며, 멀티 유즈 전략을 적극적으로 수립하는 등의 노력이 요구된다.

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Stable isotope and rare earth element geochemistry of the Baluti carbonates (Upper Triassic), Northern Iraq

  • Tobia, Faraj Habeeb
    • Geosciences Journal
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    • 제22권6호
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    • pp.975-987
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    • 2018
  • Stable isotope ratios of $^{18}O/^{16}O$ and $^{13}C/^{12}C$ and rare earth elements geochemistry of the Upper Triassic carbonates from the Baluti Formation in Kurdistan Region of Northern Iraq were studied in two areas, Sararu and Sarki. The aim of the study is to quantify the possible diagenetic processes that postdated deposition and the paleoenvironment of the Baluti Formation. The replacement products of the skeletal grains by selective dissolution and neomorphism probably by meteoric water preserved the original marine isotopic signatures possibly due to the closed system. The petrographic study revealed the existence of foraminifers, echinoderms, gastropods, crinoids, nodosaria and ostracods as major framework constituents. The carbonates have micritic matrix with microsparite and sparry calcite filling the pores and voids. The range and average values for twelve carbonate rocks of ${\delta}^{18}O$ and ${\delta}^{13}C$ in Sararu section were -5.3‰ to -3.16‰ (-4.12‰) and -2.94‰ to -0.96‰ (-1.75‰), respectively; while the corresponding values for the Sarki section were -3.69‰ to -0.39‰ (-2.08‰) and -5.34‰ to -2.70‰ (-4.02‰), respectively. The bivariate plot of ${\delta}^{18}O$ and ${\delta}^{13}C$ suggests that most of these carbonates are warm-water skeletons and have meteoric cement. The average ${\Sigma}REE$ content and Eu-anomaly of the carbonates of Sararu sections were 44.26 ppm and 1.03, respectively, corresponding to 22.30 ppm and 0.93 for the Sarki section. The normalized patterns for the carbonate rocks exhibit: (1) non-seawater-like REE patterns, (2) positive Gd anomalies (average = 1.112 for Sararu and 1.114 for Sarki), (3) super chondritic Y/Ho ratio is 31.48 for Sararu and 31.73 for Sarki which are less than the value of seawater. The presence of sparry calcite cement, negative $^{13}C$ and $^{18}O$ isotope values, the positive Eu anomaly in the REE patterns (particularly for Sararu), eliminated Ce anomaly ($Ce/Ce^{\ast}$: 0.916-1.167, average = 0.994 and 0.950-1.010, average = 0.964, respectively), and Er/Nd values propose that these carbonates have undergone meteoric diagenesis. The REE patterns suggest that the terrigenous materials of the Baluti were derived from felsic to intermediate rocks.

OpenBCI 플랫폼 기반 생체 정보 처리를 위한 데이터 패턴 모델링 (Data Pattern Modeling for Bio-information Processing based on OpenBCI Platform)

  • 이태규
    • 문화기술의 융합
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    • 제5권4호
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    • pp.451-456
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    • 2019
  • 최근 다양한 생체 정보 기술이 제안되고 있으며, 인간 환경 및 건강관리를 지원하기 위해 지속적으로 인체 관련 생체 정보 수집 및 분석에 관한 연구 및 개발이 진행 되고 있다. 이러한 생체정보 연구개발 과정은 연구개발 구성요소의 중복성과 복잡성을 증가시키고 후속 연구 개발자에게 큰 부담을 지운다. 따라서 본 연구에서는 생체 정보 플랫폼을 기반으로 생체 정보 연구 개발의 중복성과 복잡성을 개선하기 위해서 생체 정보 수집 및 분석을 효과적으로 지원하는 개방형 생체정보 플랫폼을 활용한다. 또한 생체 신호 수집, 처리, 분석 및 응용을 지원하는 개방형 인터페이스 모델을 제안한다. 특히, 개방형 인터페이스를 기반으로 뇌파 정보의 데이터 분석 모델링을 통해 생체정보 정규화 패턴 모델을 제안한다.

Finite element based dynamic analysis of multilayer fibre composite sandwich plates with interlayer delaminations

  • Jayatilake, Indunil N.;Karunasena, Warna;Lokuge, Weena
    • Advances in aircraft and spacecraft science
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    • 제3권1호
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    • pp.15-28
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    • 2016
  • Although the aircraft industry was the first to use fibre composites, now they are increasingly used in a range of structural applications such as flooring, decking, platforms and roofs. Interlayer delamination is a major failure mode which threatens the reliability of composite structures. Delamination can grow in size under increasing loads with time and hence leads to severe loss of structural integrity and stiffness reduction. Delamination reduces the natural frequency and as a consequence may result in resonance. Hence, the study of the effects of delamination on the free vibration behaviour of multilayer composite structures is imperative. The focus of this paper is to develop a 3D FE model and investigate the free vibration behaviour of fibre composite multilayer sandwich panels with interlayer delaminations. A series of parametric studies are conducted to assess the influence of various parameters of concern, using a commercially available finite element package. Additionally, selected points in the delaminated region are connected appropriately to simulate bolting as a remedial measure to fasten the delamination region in the aim of reducing the effects of delamination. First order shear deformation theory based plate elements have been used to model each sandwich layer. The findings suggest that the delamination size and the end fixity of the plate are the most important factors responsible for stiffness reduction due to delamination damage in composite laminates. It is also revealed that bolting the delaminated region can significantly reduce the natural frequency variation due to delamination thereby improving the dynamic performance.

Numerical modeling of two parallel tunnels interaction using three-dimensional Finite Elements Method

  • Nawel, Bousbia;Salah, Messast
    • Geomechanics and Engineering
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    • 제9권6호
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    • pp.775-791
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    • 2015
  • Due to the extension of communication ways (metro, highways, railways), hence, to improve traffic flow imposes often the difficult crossing that generally drive to the construction of underground works (tunnel, water conveyance tunnel...) plays a major role in the redevelopment of urban areas. This study is focused on the assessment of the interaction response of parallel tunnels, so this study uses the results from the simulation of two tunnels to illustrate a few observations that may aid in practical designs. In this article, simultaneous drilling of highway's twin tunnels is simulated by means of Finite Element Method (FEM) implemented in Plaxis program. So the treated subject appears in a setting of geotechnical where one can be to construct several tunnels sometimes in a ground of weak mechanical characteristics. The objective of this study is to simulate numerically the interaction effects caused by construction of two parallels tunnels. This is an important factor in the study of the total answer of the problem interaction between parallels underground works. The importance of the effects transmitted is function of several parameters as the type of the works, and the mechanical characteristics (tunnel size, depth, and the relative position between two tunnels, lining thickness...). This article describes numerical analyses of two parallels tunnels interaction. This study will be applied to a real case of a section tunnel T4 of the highway East-West (Algeria); the study presented below comprises a series of numerical simulations of two tunnels using the computer program Plaxis which is used in the analyses is based on Finite Element Method.

들뢰즈 영화철학 연구 - 칸트적 계기를 중심으로 (Deleuze's Cinema Philosophy and Kant)

  • 진기행
    • 철학연구
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    • 제105권
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    • pp.401-421
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    • 2008
  • 본 논문의 목적은 들뢰즈 영화철학의 구축에 있어서 칸트 철학이 행한 역할을 효과적 내지 긍정적인 측면에서 고찰하고, 그것을 통하여 들뢰즈 영화철학의 구성요소 중에서도 그다지 중요하게 다루어지지 않았던 칸트적 계기를 재조명해 보려는데 있다. 논의의 순서는 다음과 같다. 1. 들뢰즈 영화철학에 대한 베르그송, 니체, 스피노자라는 소위 '들뢰즈 3인방'을 배려하면서 그 조감도를 작성해 보려고 한다. 특히 들뢰즈의 말년의 주저인 "Cinema 1, 2권"을 중심으로 그 책의 구성을 분석하면서 들뢰즈의 영화철학의 구조를 파악하려고 한다. 2. 칸트 철학이 그 배열 안에서 어떤 위치에 있는가를 검증해 보려고 한다. 3. 거기로부터 들뢰즈 영화철학에 있어서 칸트적 계기의 의의 및 효과를 드러내 보려고 한다. 본고의 귀결이 칸트를 들뢰즈의 코페르니쿠스적 전회로서의 '사고의 이미지'론과 여러 가지 차원에서 결부지울 수 있다면 우리의 시도는 달성되었다고 보아도 좋을 것이다.