• 제목/요약/키워드: 상대성장

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Feeding Habits of Whitespotted Conger, Conger myriaster in the West Sea of Korea (한국 서해에 출현하는 붕장어(Conger myriaster)의 식성)

  • Da Yeon Kang;Do-Gyun Kim;Gi Chang Seong;Suyeon Jin;Jae Mook Jeong;Su Kyung Kang;Gun Wook Baeck
    • Korean Journal of Ichthyology
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    • v.35 no.3
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    • pp.177-182
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    • 2023
  • Total 158 Conger myriaster were examined and the range of Preanal length (PaL) was 8.2~40.1 cm and average Preanal length was 17.3 cm. Proportion of the empty stomach was 30.4% and individuals, which the prey items were found in stomach, were 110. The most important prey component in the diets of C. myriaster was Pisces that constituted 54.4% in %IRI (Index of relative importance). Engraulis japonicus was the most important prey component in Pisces. Macrura was the second largest prey component and Crangon hakodatei was the most important prey component in Macrura. The result of analysis in ontogenetic changes significantly exhibited among three size classes (<15.0 cm, 15.0~20.0 cm, ≥20.0 cm). The proportion of Macrura decreased as increasing body size, whereas the consumption of Pisces increased gradually. As body size of C. myriaster increased, the mean weight of prey per stomach (mW/ST) increased (one way-ANOVA, P<0.05).

Design of ceramics powder compaction process parameters (Part Ⅰ : Finite element analysis) (세라믹스 분말 가압 성형 공정 변수 설계(1부: 유한요소 해석))

  • Jung S. C.;Keum Y. T.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.1
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    • pp.21-26
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    • 2005
  • In order to simulate the powder compaction process and to assess the effects of packing randomness and particle arrangement 2-dimensional model of rod array compaction using quasi-random multiparticle array is introduced. The elastic modulus of porous ceramics is computed by the homogenization method. With 3 Al₂O₃ and 3 Al particles the compaction processes associated with the porosities are simulated by the explicit finite element method, based on the elastic modulus found by the homogenization method. The simulation results are compared with both previous analytical ones and experimental measurements. Finally, in order to find the relationship between the friction coefficient of powder particles and the relative density, the sensitivity analysis is performed.

Evaluation of mechanical backside damage by minority carrier recombination lifetime and photo-acoustic displacement method in silicon wafer (실리콘 웨이퍼에서 광열 변위법과 소수 반송자 재결합 수명 측정에 의한 기계적 후면 손상 평가)

  • 최치영;조상희
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.1
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    • pp.117-123
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    • 1998
  • We investigated the effect of mechanical backside damage in Czochralski grown silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductivity decay method, photo-acoustic displacement method, X-ray section topography, and wet oxidation/preferential etching methods. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and the photo-acoustic displacement values increased proportionally, and it was at Grade 1: Grade 2:Grade 3 = 1:19.6:41 that the normalized relative quantization ratio of excess photo-acoustic displacement in damaged wafer was calculated, which are normalized to the excess PAD from sample Grade 1.

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A Study of Long-term Development Plan of Korea Research Institute for Library and Information ("도서관연구소" 중장기 발전방안 연구)

  • Yoon, Hee-Yoon
    • Journal of Korean Library and Information Science Society
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    • v.39 no.2
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    • pp.5-27
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    • 2008
  • The purpose of this paper Is to present a long-term development plan for the KRILI(Korea Research Institute for Library and Information). To do so, authors analysed a various library research institutes and related organizations in U.S.A., U.K., Czech Republic, Hungary, and Japan. And using the SWOT analysis, author identified and described the current status and also surveyed recognition of library and information science faculties as to desirable roles and phase of the KRILI. Based on the results of analysis and survey, this paper suggested a long-term plan(vision and objectives, strategic issues, desirable phase and organization system, growth and development model, Internal cooperative operating systems and external research cooperation system, etc.) of the KRILI.

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Microstructural evolution in liquid-phase sintered $\alpha$-silicon carbide (액상소결 $\alpha$형 탄화규소의 미세구조 변화)

  • 이종국;강현희;박종곤;이은구
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.2
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    • pp.324-331
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    • 1998
  • After the addition of yttrium aluminum garnet of 2, 5, 10 mol% as a sintering aid, $\alpha$-silicon carbides were prepared by a liquid-phase sintering at $1850^{\circ}C$, and the microstructural evolution was investigated during sintering as functions of liquid-phase amount and sintering time. The highest apparent density in each compositions was obtained in specimens sintered for 2 h, and the percentage of weight loss increased with sintering time. By increasing the amount of sintering aid (yttrium aluminum garnet), the rate of grain growth during sintering decreased, but the apparent density of sintered body increased. The phase transformation from 6H-SiC to 4H-SiC was partially observed in specimens sintered for a long time, and so, a few rod-like grains were observed.

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Sintering and dielectric properties of $(Pb,La)TiO_3$ powder prepared by hydrothermal method (수열법에 의해 합성된$(Pb,La)TiO_3$분말의 소결 및 유전특성)

  • 김갑영;김판채;황완인;최종건
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.11 no.6
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    • pp.246-251
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    • 2001
  • The $[(Pb_{1-x}$La_{2x/3})TiO_3$, X=0.2] powder was synthesized by the hydrothermal method, and their sintering and dielectric properties according to Mn additive were examined. The relative density of sintered PLT specimen at $1150^{\circ}C$ for 5 hrs with Mn 0.02 mol% additive was 96.7%. The dielectric properties of sintered PLT specimen were changed by content of Mn and increacement of sintering temperature. Dissipation factor was improved by increasing of measuring temperature. Curie temperature of sintered PLT specimens was decreased with increasing of Mn additive.

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Preparation of $AI_2O_3/Ca-TZP$ Composites and its Characteristics ($AI_2O_3/Ca-TZP$ 복합체의 제조 및 그 특성)

  • 곽효섭;백용혁;이종국
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.2 no.2
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    • pp.63-70
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    • 1992
  • $AI_2O_3/Ca-TZP$ composites was prepared by using the starting powder of alumina and Ca-TZP synthesized by hydrothermal reaction and investigated to its characteristics. The ratio of tetragonal zirconia to monoclinic within $AI_2O_3$ matrix was decreased with an addition of Ca-TZP content, but the absolute amount of tetragonal phase in composites was increased with an addition of Ca-TZP content. The value of fracture toughness in $AI_2O_3/Ca-TZP$composites was proportional to the amounts of transformed tetragonal phase which formed by crack propagation in fracture, and therefore, it was gradually increased with an addition of Ca- TZP content.

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Behavior of Solid Phase Crystallizations in Mechanical Damage Induced Hydrogenated and Non-Hydrogenated Amorphous Amorphous Silicon Thin Films (기계적 Damage 활성화 효과에 대한 수소화 및 비수소화 비정질 규소 박막의 고상 결정화 거동)

  • Kim, Hyeong-Taek;Kim, Yeong-Gwan
    • Korean Journal of Materials Research
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    • v.6 no.4
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    • pp.436-445
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    • 1996
  • 비정질 실리콘박막의 고상결정화 특성에 대한 비정질 박막의 증착방법, 수소화 정도, 표면결정 활성화 에너지 변화 및 열처리 환경 영향을 X선 회절, EDAX, Raman 분광 분석으로 조사하였다. 저온(58$0^{\circ}C$)열처리 corning 시료에서 기판 barium(Ba), aluminum(AI) 성분의 막내 확산 임계열처리시간 및 확산에 기인 한 불안정 결정화 특성을 관찰하였다. 화학기상증착 석영 수소화 시료에서 hard damage 기계적 활성화 효과로 얻어진 조대결정립 결정화 특성을 X선 회절의 (111) 배향 상대강도 변화로 관찰 할 수 있었으며, 이는 활성화 효과에 의한 고상 결정화 시 핵생성과 성장속도변화로 다결정 실리콘의 전기적물성 향상 가능성을 보여주었다. Soft damage, bare 활성화 처리 수소화막의 결정화는 비정질 상의 혼재, 박막 응력등의 저품위 입계특성 및 미세결정립 성장 특성으로 관찰되었으나, 활성화 전처리에 의한 저온 및 고온(875$^{\circ}C$)단시간(30분) 결정화는 확인 되었다. 스퍼터링 비수소화 막의 결정화는 상변태 상태의 Raman 결정피크로 분석 되었으며, 결정화 거동에 선행막의 스퍼터링 및 비수소화 영향은 활성화효과에 관계없이 불완전 저품위 결정특성으로 확인되었다. AFM 표면형상은 3차원 island 성막특성을 보여주었고 표면거칠기정도는 높은 것으로 관찰되었다.

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Future precipitation changes in Jeju island based on CMIP6 models (CMIP6 모델을 기반으로 한 제주도 강수량의 미래 변화)

  • Kim, Sunghun;Seo, Miru;Lee, Taewon;Heo, Jun-Haeng
    • Proceedings of the Korea Water Resources Association Conference
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    • 2020.06a
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    • pp.186-186
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    • 2020
  • 본 연구에서는 IPCC (Intergovernmental Panel on Climate Change) 6차 평가보고서(6th Assessment Report, AR6)에서 제시한 새로운 온실가스 경로(SSP, Shared Socioeconomic Pathways)에 따라 산출된 전지구 기후변화 시나리오를 이용하여 제주도의 미래 강수량 변화를 살펴보고자 한다. 기상청에서 운영하는 기후정보포털(http://www.climate.go.kr/)에서는 6가지 기상요소(평균기온, 최고기온, 최저기온, 강수량, 상대습도, 풍속 등)에 대하여 SSP 시나리오 자료를 제공하고 있다. SSP 시나리오는 SSP1-2.6 저탄소 시나리오(사회 불균형의 감소와 친환경 기술의 빠른 발달로 기후변화 완화, 적응능력이 좋은 지속성장가능 사회경제 구조)와 SSP5-8.5 고탄소 시나리오(기후정책 부재, 화석연료 기반 성장과 높은 인적 투자로 기후변화 적응능력은 좋지만 완화능력이 낮은 사회경제 구조)로 구분되어 제공되고 있다. 또한, 현재의 기후 상태를 모의하는 historical period (1850-2014) 자료와 미래의 기후상태를 모의한 future period (2015-2100) 자료가 있으며, 월별(momthly), 연간(yearly) 자료의 형태로 제공된다. 본 연구를 통하여 새로운 SSP 시나리오를 이용한 제주도 강수량의 미래 변화를 정량적으로 분석하였고, 기후변화에 능동적인 대책을 수립하는데 도움이 될 것으로 판단된다.

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Venture Capital Financing and Market Performance of Entrepreneurial Firms (공동투자가 중소기업의 성과에 미치는 영향: 벤처캐피탈을 중심으로)

  • Lim, Eun-Cheon;Kim, Dohyeon
    • Korean small business review
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    • v.39 no.2
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    • pp.19-35
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    • 2017
  • It is very important for entrepreneurial firms to acquire and exploit the resources necessary for growth. This study examines how venture capital financing affect these entrepreneurial firms' ability to acquire and exploit the resources. Particularly, based on the resource based view, the authors explain the relationship between venture capital financing and entrepreneurial firm's market performance. Empirical results illustrate that venture capital financing positively and significantly affects the market performance of entrepreneurial firms. It is concluded that entrepreneurial firms need to increase the number of alliances with venture capital, which supports various activities after the investment to achieve growth with resource limitation.