• 제목/요약/키워드: Morphological Evolution

검색결과 398건 처리시간 0.053초

거미류의 생태적 진화에 관한 연구 (Ecological Evolution of the Spiders)

  • 김주필
    • 한국토양동물학회지
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    • 제4권2호
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    • pp.61-68
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    • 1999
  • 약 4억만년 전에 출현하였을 거미류의 진화를 생태학적인 측면에서 수중생활, 낙엽층 속에서의 생활, 토양틈사이에서의 생활, 땅속에서의 생활, 동굴에서의 생활, 지표위에서의 배회생활, 공중에서 거미그물을 치면서의 생활하는 과정과 그에 속하는 거미류의 종류와 형태변화 등에 관해 진화적인 측면에서 조사연구하여 정리 보고하고자 한다. 우리나라에 존재하지 않는 거미과명의 국명은 Kim (1998c)의 방식에 따랐다.

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First Record of Indo-West Pacific Spider Crab, Naxioides robillardi (Decapoda: Epialtidae) from Korean Waters

  • Lee, Sang-Hui;Jung, Jibom;Park, Taeseo
    • Animal Systematics, Evolution and Diversity
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    • 제36권4호
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    • pp.400-407
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    • 2020
  • An epialtid spider crab, Naxioides robillardi (Miers, 1882), is known as widely distributed in Indo-West Pacific region include Japanese waters. Four specimens of epialtid crabs were collected from adjacent waters of Jejudo Island and identified as N. robillardi. This species can be grouped into two forms such as N. robillardi form typical and N. robillardi form mammillata according to morphological features of carapace, gastric spine, and chela. Morphological characters of all Korean specimens well agree with the form mammillata in general. In this paper, morphological diagnosis and illustrations of newly collected N. robillardi are provided. DNA barcode sequence of COI region is also determined for the first time.

Grooming Behavior and a Possible Morphological Structure for Secretions from Abdominal Glands of a Korean Wood-eating Cockroach, Cryptocercus kyebangensis (Insecta: Blattodea)

  • Park, Yung-Chul;Kim, Joo-Pil;Choe, Jae-Chun
    • Animal Systematics, Evolution and Diversity
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    • 제22권1호
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    • pp.17-22
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    • 2006
  • Cryptocercus nymphs periodically groom ventral surface of their parents. The grooming might be licking-behavior to obtain secretions from the ventral surface of their parents, and some essential nutrients or hormones that facilitate nymphal development might be included in the secretions. We tried to find morphological structures for secretion outlets on the ventral surface. The deep depressions around setae were present, and their shape was an external morphological structure that liquid secretions from internal glands are likely to be well seized. There were also small holes on the depressions that might be external openings for secretions from the sternal glands. Another possible region on body surface for outlets of secretions might be the apophyses. In Cryptocercus individuals, mucous liquid on body surface was relatively highly present around coxa. The intercoxal apodemes, to which muscles are attached and which open externally between the mid and hindcoxae, might have evolved a secondary function of producing nourishment for the young.

일축신장흐름에서의 PS/HDPE Blend의 모폴로지 변화에 관한 연구 (Study on the Morphology Evolution of PS/HDPE Blend During Uniaxial Elongational Flow)

  • Hong, Jung-Sook;Son, Jung-Wu;Lee, Seung-Jae;Ahn, Kyung-Hyun;Lee, Seung-Jong
    • 한국유변학회:학술대회논문집
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    • 한국유변학회 2001년도 춘계 학술발표회 논문집
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    • pp.11-14
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    • 2001
  • Our study have aimed to identify the deformation and breakup mechanism of minor phase in polymer blends under uniaxial enlongational flow. Experimentally, we measured the transient elongational viscosity of PS/HDPE blends using the uniaxial elongational rheometer at two temperatures. And we observed the evolution of blend morphology with elongation time. Morphological change was observed by quenching the specimen after deformation. If the viscosity variation of PS was compared with that of HDPE at each temperature, PS showed larger temperature dependence than HDPE. At 155$^{\circ}C$, the dispersed phase of larger size were easily affected by affine deformation. The initial spherical shape changed to flat ellipsoid at first, then flat ellipsoid to bulbous shape, and bulbous to thin thread and its satellites. But dispersed phase of smaller size showed the change from sphere to ellipsoid. At 175$^{\circ}C$, the dispersed phase were mostly deformed from spherical shape to ellipsoid. As a result, the morphological change of dispersed phase in elongational deformation is affected by chain flexibility and viscosity ratio. We need to further study to make sure the mechanism of elongation of viscoelastic polymer blends.

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유방조영 영상의 대비개선을 위한 형체기반 호모몰픽필터 (Morphology-Based Homomorphic Filter for Contrast Enhancement of Mammographic Images)

  • 황희수
    • 한국지능시스템학회논문지
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    • 제20권4호
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    • pp.522-527
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    • 2010
  • 본 논문은 유방 조영 영상의 대비를 향상시키기 위해 새로운 호모몰픽 필터(MBHF)를 제안한다. 제안된 필터는 영상을 형체적으로 다수 분할한 후 각각의 형체 즉, 서브-밴드에 대해 그 구성요소와 이득이 차분진화를 통해 최적의 값을 갖도록 설계된다. 결과 분석을 통해 제안된 방법이 영상 대비를 향상시키는 것을 보이며 웨이블렛 기반의 호모몰픽 필터와 성능이 비교된다. 성능평가 기준으로는 인간의 시각적 인식을 고려한 WPSNR(Weighted Peak Signal to Noise Ratio)을 사용한다.

에틸렌/공기 역확산 화염에서의 초기 매연 입자의 성장 특성 (The evolution characteristics of incipient soot particles in ethylene/air inverse diffusion flame)

  • 오광철;이은도;신현동;이의주
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1172-1177
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    • 2004
  • The evolution of incipient soot particles has been examined by high resolution electron microscopy (HRTEM) and elemental analyzer in ethylene-air inverse diffusion flames. Laser Induced Incandescence(LII) and laser scattering methods were introduced for examining the change of soot volume fraction and morphological properties in combustion generated soot qualitatively. Soot particles, collected by thermophoretic sampling were analyzed by using HRTEM to examine the nano structure of precursor particles. HRTEM micrographs apparently reveal a transformation of condensed phase of semitransparent tar-like material into precursor particles with relatively distinct boundary and crystalline which looks like regular layer structures. During this evolution histories C/H analysis was also performed to estimate the chemical evolution of precursor particles. The changes of C/H ratio of soot particles with respect to residence time can be divided into two parts: one is a very slowly increasing regime where tar-like materials are transformed into precursor particles (inception process) the other is an increasing region with constant rate where surface growth affects the increase of C/H ratio dominantly (surface growth region). These results provide a clear picture of a transition to mature soot from precursor materials.

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에틸렌/공기 역확산 화염에서의 초기 매연 입자의 성장 특성 (The evolution characteristics of incipient soot particles in ethylene/air inverse diffusion flame)

  • 오광철;이은도;신현동;이의주
    • 한국연소학회지
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    • 제9권2호
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    • pp.38-44
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    • 2004
  • The evolution of incipient soot particles has been examined by high resolution electron microscopy (HRTEM) and elemental analyzer in ethylene-air inverse diffusion flames. Laser Induced Incandescence(LII) and laser scattering methods were introduced for examining the soot volume fraction and morphological properties in combustion generated soot qualitatively. Soot particles, collected by thermophoretic sampling, were analyzed by using HRTEM to examine the nano structure of precursor particles. HRTEM micrographs apparently reveal a transformation of condensed phase of semitransparent tar-like material into precursor particles with relatively distinct boundary and crystalline which looks like regular layer structures. During this evolution histories, C/H analysis was also performed to estimate the chemical evolution of precursor particles. The changes of C/H ratio of soot particles with respect to residence time can be divided into two parts: one is a very slowly increasing regime where tar-like materials are transformed into precursor particles (inception process) the other is an increasing region with constant rate where surface growth affects the increase of C/H ratio dominantly (surface growth process). These results provide a clear picture of a transition to mature soot from precursor materials.

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THE EVOLUTION OF THE GALACTIC GLOBULAR CLUSTERS.: I. METAL ABUNDANCE CALIBRATIONS

  • Lee, See-Woo;Park, Nam-Kyu
    • 천문학회지
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    • 제17권2호
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    • pp.69-103
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    • 1984
  • Five different calibrations of metal abundances of globular clusters are examined and these are compared with metallicity ranking parameters such as $(Sp)_c$, . Q39 and IR-indices. Except for the calibration $[Fe/H]_H$ by the high dispersion echelle analysis. the other calibration scales are correlated with the morphological parameters of red giant branch. In the $[Fe/H]_H$-scale. the clusters later than ${\sim}F8$ have nearly a constant metal abundance. $[Fe/H]_H{\simeq}-1.05$, regradless of morphological characteristics of horizontal branch and red giant branch. By the two fundamental calibration scales of $[Fe/H]_L$ (derived by the low dispersion analysis) and $[Fe/H]_{{\Delta}s}$ (derived by the spectral analysis of RR Lyrae stars). the globular clusters are divided into the halo clusters with [Fe/H]<-1.0 and the disk clusters confined within the galactocentric distance ${\tau}_G=10\;kpc$ and galactic plane distance |z|=3 kpc. In this case the abundance gradient is given by d[Fe/H]/$dr_G{\approx}-0.05\;kpc^{-1}$ and d[Fe/H]/$d|z|{\simeq}-0.08\;kpc^{-1}$ within ${\tau}_G=20\;kpc$ and |z|=10 kpc, respectively. According to these characteristics of the spatial distribution of globular clusters. the chemical evolution of the galactic globular clusters can be accounted for by the two-zone (disk-halo) slow collapse model when the $[Fe/H]_L$-or $[Fe/H]_{{\Delta}s}$-scale is applied. In the case of $[Fe/H]_H$-scale, the one-zone fast collapse model is preferred for the evolution of globular clusters.

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