• Title/Summary/Keyword: Evolution of research area

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Simultaneous Synthesis and Rapid Consolidation of Nanostructured (Ti,Mo)C and Its Mechanical Properties (펄스전류 가열에 의한 나노구조의 (Ti,Mo)C 합성과 동시 급속소결 및 기계적 성질)

  • Jo, Hyoung-Gon;Kwon, Hanjung;Shon, In-Jin
    • Korean Journal of Materials Research
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    • v.23 no.11
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    • pp.620-624
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    • 2013
  • Nanocrystalline materials have recently received significant attention in the area of advanced materials engineering due to their improved physical and mechanical properties. A solid-solution nanocrystalline powder, (Ti,Mo)C, was prepared via high-energy milling of Ti-Mo alloys with graphite. Using XRD data, the synthesis process was investigated in terms of the phase evolution. Rapid sintering of nanostuctured (Ti,Mo)C hard materials was performed using a pulsed current activated sintering process (PCAS). This process allows quick densification to near theoretical density and inhibits grain growth. A dense, nanostructured (Ti,Mo)C hard material with a relative density of up to 96 % was produced by simultaneous application of 80 MPa and a pulsed current for 2 min. The average grain size of the (Ti,Mo)C was lower than 150 nm. The hardness and fracture toughness of the dense (Ti,Mo)C produced by PCAS were also evaluated. The fracture toughness of the (Ti,Mo)C was higher than that of TiC.

Application of Remotely Sensed Data and Geographic Information System in Watershed Management Planning in Imha, Korea

  • CHAE Hyo-Sok;LEE Geun-Sang;KIM Tae-Joon;KOH Deuk-Koo
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.361-364
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    • 2005
  • The use of remotely sensed data and geographic information system (GIS) to develop conservation-oriented watershed management strategies on Imha Dam, Korea, is presented. The change of land use for study area was analyzed using multi-temporal Landsat imagery. A soil loss model was executed within a GIS environment to evaluate watershed management strategies in terms of soil loss. In general, remotely sensed data provide efficient means of generating the input data required for the soil loss model. Also, GIS allowed for easy assessment of the relative erosion hazard over the watershed under the different land use change options. The soil loss model predicted substantial declines in soil loss under conservation-oriented land management compared to current land management for Imha Dam. The results of this study indicate that soil loss potential (5,782,829 ton/yr) on Imha Dam in 2003 is approximately 1.27 times higher than that (4,557,151 ton/yr) in 1989. This study represents the first attempt in the application of GIS technology to watershed conservation planning for Imha Dam. The procedures developed will contribute to the evolution of a decision support system to guide the land planning and dam management in Imha Dam.

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Short Periodicities in Latitudinal Variation of Sunspots

  • Kim, Bang-Yeop;Chang, Heon-Young
    • Journal of Astronomy and Space Sciences
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    • v.28 no.2
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    • pp.103-108
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    • 2011
  • The latitudinal variation of sunspots appearing during the period from 1874 to 2009 has been studied in terms of centerof-latitude (COL). The butterfly diagram has been used to study the evolution of the magnetic field and the dynamics at the bottom of the solar convection zone. Short-term periodicities have been of particular interest, in that they are somehow related to the structure and dynamics of the solar interior. We thus have focused our investigation on shortterm periodicities. We first calculated COL by averaging the latitude of sunspots with the weight function in area. Then, we analyzed the time series of COL using the wavelet transform technique. We found that a periodicity of ~5 years is the most dominant feature in the time series of COL, with the exception of the ~11 year solar cycle itself. This periodicity can be easily understood by considering small humps between the minima in the area-weighted butterfly diagram. However, we find that periodicities of ~1.3 (0.064), ~1.5 (0.056), or ~1.8 (0.046) years ($\frac{1}{month}$), month ), which have been previously suggested as evidence of links between the changing structure of the sunspot zone and the tachocline rotation rate oscillations, are insignificant and inconsistent. We therefore conclude that the only existing short-term periodicity is of ~5 years, and that periodicities of ~1.3, ~1.5, or ~1.8 years are likely to be artifacts due to random noise of small sunspots.

Characteristics of Prospect and Refuge in Gyeongbokgung Palace focusing on the Biophilic Design (바이오필릭 디자인의 관점에서 본 경복궁의 전망과 은신처 분석)

  • Hwang, Ji-Hyoun;Lee, Hyunsoo
    • Korean Institute of Interior Design Journal
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    • v.24 no.5
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    • pp.3-11
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    • 2015
  • The human instinct toward nature is biophilia as a psychological term. There have been a number of empirical evidences confirmed that natural features in buildings enhance human's comfort focusing on biophilia. However, the evolution of society, science, and industry has separated modern buildings from nature. Therefore, this paper addresses the assumption that the admiration for historical buildings in contemporary society is attribute to the qualities of biophilic design. Prospect and refuge, one of the strategies for biophilic design, ultimately provides the opportunity to recover from stress and tension. The purpose of this study is to figure out elements of prospect and refuge based on the design theory of biophilia for psychological healing. This study explores the Gyeongbokgung Palace with the design elements of prospect and refuge in biophilia. It also measures these elements quantitatively with the contrast using Adobe Photoshop CS6, and the area ratio of prospect and refuge. The results of this research verify that the conflicting characteristics of prospect and refuge are identified simultaneously, it is significant to attract people. Gangnyeongjeon Hall and Gyotaejeon Hall, the living quarters for the king and queen, propose the intense pattern of refuge characteristics more than other areas. The mathematical properties of the area ratio show that the pattern of prospect-refuge characteristics change in particular design elements.

Surface Heat Flux and Oceanic Heat Advection in Sendai Bay

  • Yang Chan-Su;Hanawa Kimio
    • Korean Journal of Remote Sensing
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    • v.22 no.1
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    • pp.11-24
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    • 2006
  • Coastal sea surface temperature (CSST) and meteorological data from January through December 1995 are used to estimate the net surface heat flux and heat content for Sendai Bay. The average annual surface heat flux in the area north of the bay is estimated to be $+35Wm^{-2}$, whereas the southwestern area is estimated to be $+56Wm^{-2}$. Therefore, the net surface heat flux shows a net gain of heat over the whole bay. The largest heat gain occurs near Matsukawaura, where the strong Kuroshio/Oyashio interaction produces anomalously cold SST and wind is more moderate than in other regions of Sendai Bay over most of the year. The lowest heat gain occurs around Tashiro Island, where the temperature difference between air and sea surface is lower and wind is stronger. The heat budget shows that both surface forcing and horizontal advection are potentially important contributors to the seasonal evolution of CSST in the bay. From the A VHRR and SeaWiFS data, it is found that offshore conditions between the bay and Eno Island are different due to the presence of the Ojika Peninsula. It is also shown that the temporal behaviors of SSTs in the bay are closely connected with the air-sea heat flux and offshore conditions.

Firing Condition, Source Area and Quantitative Analysis of Plain Coarse Pottery from the Unjeonri Bronze Age Relic Site, Cheonan, Korea (천안 운전리 청동기 유적지에서 출토된 무문토기의 정량분석, 산지 및 소성조건)

  • Choi, Seok-Won;Lee, Chan-Hee;Oh, Kuy-Jin;Lee, Hyo-Min;Lee, Myeong-Seong
    • Korean Journal of Heritage: History & Science
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    • v.36
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    • pp.267-297
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    • 2003
  • The plain coarse pottery from the Unjeonri Bronze Age relic sites in the Cheonan, Korea were studied on the basis of clay mineralogy, geochemistry and archaegeological interpretations. For the research, the potteries are utilized at the analysis for 6 pieces of plain coarse potteries. Color of the these potteries are mainly light brown, partly shows the yellowish brown to reddish brown. The interior, surface and inside of the pottery appear as different colors in any cases. Original source materials making the Unjeonri potteries are used of mainly sandy clay soil with extreme coarse grained irregularly quartz and feldspar. The magnetic susceptibility of the Unjeonri pottery range from 0.20 to 1.20. And the Unjeonri soil's magnetic susceptibility agree almost with 0.20 to 1.30. In the same magnetization of soil and pottery, the results revealed that the Unjeonri soil and low material of pottery are same produced by identical source materials. The Unjeonri potteries and soil are very similar patterns with all characteristics of soil mineralogy, geochemical evolution trend. The result seems to be same relationships between the behavior and enrichment patterns on the basis of a compatible and a incompatible elements. Consequently, the Unjeonri potteries suggest that made the soil to be distributed in the circumstance of the relic sites as the raw material are high in a greater part. In the Unjeonri soil, the kaolinite is common occurred minerals. However, in the Unjeonri pottery, the kaolinite was not detected in all broken pieces. The kaolinite was presumed to destroy crystal structure during the firing processes of over $550^{\circ}C$. The quartz is phase transition from ${\alpha}$-quartz to ${\beta}$-quartz at $573^{\circ}C$, but the Unjeonri pottery did not investigated any phase transition evidences of quartz. The chorite was detected within the mostly potteries and soils. As the results, the Unjeonri potteries can be interpreted by not experiencing a firing temperature over $800^{\circ}C$. The colloidal and cementing materials between the quartz and low materials during the heating did not exist in the internal part of the potteries. An any secondary compounds by heating does not appear within the crack to happen during the dry of the pottery. The hyphae group are kept as it is with the root tissue of an organic matters to live in the swampy land. In the syntheses of all results, the general firing condition to bake and make the Unjeonri pottery is presumed from $550^{\circ}C$ to $800^{\circ}C$. However, the firing condition making the Unjeonri pottery can be different firing temperature partially in one pottery. Even, the some part of the pottery does not take a direct influence on the fire.

Principles for Helpful Sequence and Deduction of Knowledge Organization Systems - An Exploratory Study

  • Asundi, A.Y.
    • Journal of Information Science Theory and Practice
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    • v.1 no.2
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    • pp.6-15
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    • 2013
  • Dr. Ranganathan's "Principles for Helpful Sequence" among the set of normative principles play an exclusive role in the arrangement of subject isolates. Each subject in the universe of subjects is regulated by a guiding principle of its own which analogously determines the sequence of Arrays in ordering the subject surrogates or isolates. For example, the "Principle of Later-in-Evolution" is applied for sequencing isolates of Animal and Plant Species; this concept can be applied to one of the tools of KOS viz. Taxonomies. The application of Principles for Helpful Sequence is summarily presented and in the process the paper highlights the inherent elements of knowledge organization in each one of these principles in a manner that might map the future course of research in this area with the potentiality to bring about a relation between principles for helpful sequence and KOS.

Genomic Research of the Genus Bifidobacterium and Its Application (비피도박테리아의 분자생물학적인 연구 동향)

  • Kim, Geun-Bae
    • Journal of Dairy Science and Biotechnology
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    • v.25 no.2
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    • pp.21-28
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    • 2007
  • Recently, the field of microbiology has been transformed by huge increasing number of publicly available whole-genome sequences. This sequence information has significantly enhanced our understanding of the physiology, genetics, and evolutionary development of bacteria. Among the gastrointestinal microorganisms, bifidobacteria represent the most important human commensals because of their contribution to maintaining a balanced gastrointestinal tract microbiota. In recent years bifidobacteria have drawn much scientific attention due to their use as live bacteria in numerous food products with various health-related claims. For this reason, these bacteria constitute a growing area of interest with respect to genomics, molecular biology, and genetics. Recent genome sequencing of a number of bifidobacterial species has allowed access to the complete genetic make-up of these bacteria. This review will focus how genomic data has allowed us to understand bifidobacterial evolution, while also revealing genetic functions that explains their presence in the particular ecological environment of the gastrointestinal tract.

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Genomic Research as a Means to Understand Bacterial Phylogeny and Ecological Adaptation of the Genus Bifidobacterium (Bifidobacterium의 분자생물학적 연구 동향)

  • Kim, Geun-Bae
    • 한국유가공학회:학술대회논문집
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    • 2007.09a
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    • pp.21-29
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    • 2007
  • The field of microbiology has in recent years been transformed by huge increasing number of publicly available whole-genome sequences. This sequence information has significantly enhanced our understanding of the physiology, genetics, and evolutionary development of bacteria. Among the gastrointestinal microorganisms, bifidobacteria represent important human commensals because of their perceived contribution to maintaining a balanced gastrointestinal tract microbiota. In recent years bifidobacteria have drawn much scientific attention due to their use as live bacteria in numerous food products with various health-related claims. For this reason, these bacteria constitute a growing area of interest with respect to genomics, molecular biology, and genetics. Recent genome sequencing of a number of bifidobacterial species has allowed access to the complete genetic make-up of these bacteria. This review will focus how genomic data has allowed us to understand bifidobacterial evolution, while also revealing genetic functions that explains their presence in the particular ecological environment of the gastrointestinal tract.

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Three Species of Spilomelinae (Lepidoptera, Crambidae) New to Korea

  • Sohn, Jae-Cheon;Kim, Sung-Soo;Choi, Sei-Woong
    • Animal Systematics, Evolution and Diversity
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    • v.37 no.1
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    • pp.33-38
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    • 2021
  • Three species of Spilomelinae, Camptomastix septentrionalis Inoue, 1982, Omiodes indistinctus (Warren, 1892) and Piletocera aegimiusalis (Walker, 1859), are reported for the first time from Korea. Camptomastix septentrionalis is distinguished from Camptomastix hisbonalis (Walker, 1859) in the smaller body size, the lack of a clear discal spot on the forewings, and having the less protruding costa of the valva in the male genitalia and the smaller antrum in the female genitalia. Omiodes indistinctus is distinguished from Omiodes tristrialis(Bremer, 1864) in having the narrower forewings with the faded postmedian and subbasal lines and a densely-setose, sclerotized area on the terminal part of uncus dorsally in the male genitalia. Piletocera aegimiusalis is distinguished from Piletocera sodalis(Leech, 1889) in the larger body size and the lack of a pale yellow patch on the hindwings. Photos of the external and genital features are provided for the three newly-recorded spilomeline species.