• 소성∙가공
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• 제13권2호
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• pp.174-179
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• 2004

The effect of grain refinement on the plastic deformation behaviour of nanocrystalline metallic materials is investigated. A phase mixture model in which a single phase material is considered as an effectively two-phase one is discussed. A distinctive feature of the model is that grain boundaries are treated as a separate phase deforming by a diffusion mechanism. For the grain interior phase two concurrent mechanisms are considered: dislocation glide and mass transfer by diffusion. The proposed constitutive model was implemented into a finite element code (DEFORM) using a semicoupled approach. The finite element method was applied to simulating room temperature tensile deformation of Cu down to the nanoscale grain size in order to investigate the pre- and post-necking behaviour.

• 한국측량학회지
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• 제9권2호
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• pp.67-72
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• 1991

OSU89B를 이용하여 한반도 일원의 지오이드와 수직선편차에 대하여 연구하였다. 한반도 일원에서 지오이드는 GRS1980 지구타원체에 비해 +3m~+35m 범위의 변화를 나타내며, 전반적으로 서에서 동으로 높아져 감이 특징적이다. 수직선편차는 $\xi$가 -8.9"~8.0", $\eta$가 -13.1"~9.0"의 범위의 변화를 보이며 전반적으로 서편경향이 특징적이다.며 전반적으로 서편경향이 특징적이다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.44-46
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• 2008

Air-breathing polymer electrolyte membrane fuel cells (PEMFC) are highly promising particularly for small-power applications up to tens watts class. A distinctive feature of the air-breathing PEMFC is its simple system configuration in which axial fans operate for dual purposes, supplying both oxidant and coolant in a single manner. In the present study, a nominal 80W air-breathing PEMFC system is developed and investigated to determine the optimal operating strategy through parametric studies (i.e., reactant humidity, and fanblowing flow rate). The cell voltage distributions are examined as a function of time to evaluate the system performance under various operating conditions.

• 한국분말재료학회지
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• 제8권3호
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• pp.168-173
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• 2001

The effect of grain refinement of the strength and ductility of metallic materials is investigated. A model in which a single phase material is considered as an effectively two-phase one is discussed. A distinctive feature of the model is that grain boundaries are treated as a separate phase deforming by a diffusion mechanism. Deformation of the grain interior phase is assumed to be carried by two concurrent mechanism. Deformation of the grain interior phase is assumed to be carried by two concurrent mechanisms: dislocation glide and mass transfer by diffusion. The model was exemplified by simulating uniaxial tensile deformation of Cu down to the nanometer grain size. The results confirm the observed strain hardening behaviour and a trend for reduction of ductility with decreasing grain size at room temperature.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.405-410
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• 2004

2-dimensional impeller's distinctive feature is expected to have an influence on performance and flow characteristics of centrifugal compressor. And new design method is required for 2-dimensional impeller, because the unique geometry cannot be designed using conventional theories. The objective of this study is to advance new design technology for 2-dimensional impeller and to investigate the performance characteristics of designed 2-dimensional centrifugal compressor. The performance test for 2-dimensional impeller is conducted at 35000, 40000 and 45000rpm. Also numerical calculation is applied by using commercial CFD code, FLUENT, and the results are compared with experimental results.

• Nuclear Engineering and Technology
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• 제47권5호
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• pp.588-595
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• 2015

This study presents an effective method for additional recovery of residual actinides in liquid electrodes after the electrowinning process of pyroprocessing. The major distinctive feature of this method is a reactor with multiple reaction cells separated by partition walls in order to improve the recovery yield, thereby using the interelement difference in diffusion coefficients within the liquid electrode and controlling the selectivity and purity of element recovery. Through an example of numerical simulation of the diffusion scenarios of individual elements, we verified that the proposed method could effectively separate the actinides (U and Pu) and rare-earth elements contained in liquid cadmium. We performed a five-step consecutive recovery process using a simplified conceptual reaction cell and recovered 58% of the initial amount of actinides (U + Pu) in high purity (${\geq}99%$).

• 영어어문교육
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• 제16권3호
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• pp.253-268
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• 2010

Robert Lowell is one of the major poets in the modern American poetic world. His major work, Life Studies, is a representative of confessional poetry. It presented American spiritual civilization and universality for life from the late 1950s to 1960s. It dealt with the subject of the poet's private life under the psychological pressure. Lowell described his distinctive vision of the relationship of painful world and suffering self in his poetry. An important feature of his confessional poems was the criticism on modern civilization by means of characterization. Life Studies was written as a kind of therapy to overcome his early trauma, as well as the social problems of contemporary Americans which Lowell was confronted with. Through his personal experiences, Lowell exposed and judged the collapse of traditional value and moral confusion in the society. Therefore, he is a poet who opened his own world of poetry with his poetic achievements.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.253-256
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• 2000

This paper describes a DSP implementation of a real-time 3D sound localization algorithm with the use of a low power embedded DSP. A distinctive feature of this implementation is that the audible frequency band is divided into three, in accordance with the sound reflection and diffraction phenomena through different media from a certain sound source to human ears, and then in each subband a specific implementation procedure of the 3D sound localization is devised so as to operate real-time at a low frequency of 50MHz on a 16bit fixed-point DSP. Thus out DSP implementation can provide a listener with 3D sound effects through a headphone at low cost and low power consumption.

• 한국주거학회논문집
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• 제21권4호
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• pp.59-69
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• 2010

Imwongyeongjeji, Administration of Our Daily Life in Woods and Fields, is a sort of encyclopedia compiled by Seo, Yoo Goo in Joseon Dynasty in the 19th century. This voluminous work is made up of 16 chapters with various references including many articles dealing with architecture. The chapter Seomyongji covering the daily necessities contains a number of methods and materials of building construction. The distinctive feature of these articles is that they are mostly from Joseon's books. It is not similar to other chapters which are made of quotations from Chinese books. Especially, he quoted many of articles about architecture from his own work Geumhwagyeongdokgi, Record of Plowing and Reading in Geumhwa. In addition, He selected only empirical knowledge, put it in the book, and commented on it in his judgment. These articles provide valuable information on architectural knowledge in late Joseon period.

• Journal of Plant Biology
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• 제29권2호
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• pp.129-133
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• 1986

Transections of the stem region close to the shoot apex show the occurrence of an outer, complete ring of procambium and an inner group of discrete procambial strands. From the outer ring, small, discrete vascular bundles and vascular cambium originate, while the inner group forms the discrete, medullary vascular bundles with intrafascicular cambium. Secondary thickening is essentially due to the activity of the cylinder or complete ring of vascular cambium that originates from the procambium. The medullary intrafascicular cambia also form some secondary tissues. The vascular cambium produces secondary xylem inwards and secondary phloem outwards as in the normal secondary thickening process. The distinctive feature, however, is perpetual discreteness of the medullary vascular bundles. No successive series of cambia or secondary vascular bundles are found.