• Title/Summary/Keyword: inner layer

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Effect of Extracellular Matrix on the Growth Behavior of Corneal Endothelial Cells to Poly(lactic-co-glycolic acid) Film (각막 내피세포 성장 거동에 대한 락타이드 글리콜라이드 공중합체 필름과 세포외 기질의 효과)

  • Kim, Eun Young;Kim, Hye Min;Song, Jeong Eun;Lee, Hyun Soo;Joo, Choun-Ki;Khang, Gilson
    • Polymer(Korea)
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    • v.38 no.6
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    • pp.702-707
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    • 2014
  • Corneal endothelium is mono-inner cell layer of cornea and lay on Descmet's membrane which comprised of various proteins called extracellular matrix such as fibronectin, collagen, laminin, and proteoglycan, etc. In this study, we fabricated transparent poly(lactic-co-glycolic acid) (PLGA) film because PLGA is widely used for tissue engineering based on their properties. We investigated the behaviors of rabbit corneal endothelial cells (rCEnCs) on PLGA film surfaces coated with various cell-adhesive molecules like fibronectin, laminin, collagen type I and IV and FNC coating mix. The morphologic images, proliferation and adhesion assay, immunofluorescence for ZO-1 and $Na^+/K^+-ATPase$ and RT-PCR for expression of specific markers were conducted. These results showed that PLGA film plays a role as CEnC carriers in vitro and the cell-adhesive molecules give positive effects on the behaviors of rCEnC.

Characteristics of the Stress Path of a Sabkha Layer Consisting of Carbonate Sand, as Obtained by the Triaxial Test after Particle Crushing (Sabkha층 탄산질 모래의 삼축압축시 입자파쇄로 인한 응력경로 특성)

  • Kim, Seok-Ju;Yi, Chang-Tok;Jang, Jae-Ho;Han, Heui-Soo
    • The Journal of Engineering Geology
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    • v.24 no.1
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    • pp.23-38
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    • 2014
  • The composition of carbonate sands from a sabkha at Ruwais in the UAE differs from that of silica sand, and these sands are crushed easily under low compression pressures. Accordingly, particle crushing of carbonate sand occurs under high pressure, which results in additional settlement and reduces the shear strength. In this study, consolidation and triaxial tests were conducted to analyze the characteristics of carbonate sands following particle crushing. The unusual shear strength graphs of the carbonate sands result from the degree of particle pre-crushing. For the range at p' > p in the p (p')-q diagram, negative (-) excess porewater pressures occur if the axial pressure causes particle crushing that induces exposure of the inner voids. In addition, the q value decreased after particle crushing. In conclusion, the unusual characteristics of the carbonate sands were induced by particle crushing. The triaxial tests revealed that the degree of particle pre-crushing influenced the excess porewater pressure.

Reconstruction of the Volcanic Lake in Hanon Volcano Using the Spatial Statistical Techniques (공간통계기법을 이용한 하논화산의 화구호 복원)

  • Choi Kwang-Hee;Yoon Kwang-Sung;Kim Jong-Wook
    • Journal of the Korean Geographical Society
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    • v.41 no.4 s.115
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    • pp.391-403
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    • 2006
  • The Hanon volcano located in the southern pan of Cheju Island, Korea has a wetland in its crater being used as a farmland. Previous researchers presumed this wetland was a maar lake in the past. Based on the seismic refraction method, the wetland sediment layer was estimated between 5 to 14 m deep, which is mostly in accordance with previous researches. However, this shows only the depths at some sites, not representing the whole spatial distribution. This study is an attempt to reconstruct the volcanic lake in Hanon crater by applying the spatial statistical techniques based on the depth information from the seismic survey and known data. The procedure of reconstruction is as follows: First, the depth information from the seismic survey and known data were collected and it was interpolated by IDW and Ordinary Kriging method. Next, with the interpolation map and the present DEM the paleo DEM was constructed. Finally, using the paleo lake level on core data, the boundary of volcanic lake was extracted from the paleo DEM. The reconstructed lake resembles a half-moon in the north of the central scoria cone. It is estimated that the lake was 5 m deep on average and 13 m deep at the deepest point. Although there are slight differences according to the interpolation techniques, it is calculated that the area of the lake was between 184,000 and $190000m^2,$ and its volume approximately $869,760m^3$. Because of the continuous deposition processes after the crater formation, the reconstructed volcanic lake would not indicate an actual lake at a specific time. Nevertheless, it offers a significant clue regarding the inner morphology and evolution of the crater.

Studies on the Interfacial Reaction between electroplated Eutectic Pb/Sn Flip-Chip Solder Bump and UBM(Under Bump Metallurgy) (전해 도금법을 이용한 공정 납-주석 플립 칩 솔더 범프와 UBM(Under Bump Metallurgy) 계면반응에 관한 연구)

  • Jang, Se-Yeong;Baek, Gyeong-Ok
    • Korean Journal of Materials Research
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    • v.9 no.3
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    • pp.288-294
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    • 1999
  • In the flip chip interconnection using solder bump, the Under Bump Metallurgy (UBM) is required to perform multiple functions in its conversion of an aluminum bond pad to a solderable surface. In this study, various UBM systems such as $Al 1\mu\textrm{m} / Ti 0.2\mu\textrm{m} / Cu 5\mu\textrm{m}, Al 1\mu\textrm{m} / Ti 0.2\mu\textrm{m} / Cu 1\mu\textrm{m}, al 1\mu\textrm{m}/Ni 0.2\mu\textrm{m} / Cu 1\mu\textrm{m} and Al 1\mu\textrm{m}/Pd 0.2\mu\textrm{m} / Cu 1\mu\textrm{m}$ for flip chip interconnection using the low melting point eutectic 63Sn-37Pb solder were investigated and compared to their metallurgical properties. $100\mu\textrm{m}$ size bumps were prepared for using an electroplating process. The effects of the number of reflows and aging time on the growth of intermetallic compounds(IMC) were investigated. $Cu_6Sn_5$ and $Cu_3Sn$ IMC were abserved after aging treatment in the UBM system with thick coper $(Al 1\mu\textrm{m}/Ti 0.2\mu\textrm{m}/Cu 5\mu\textrm{m})$. However only the $Cu_6Sn_5$ was detected in the UBM system with $1\mu\textrm{m}$ thick copper even after 2 reflow and 7 day aging at $150^{\circ}C$. Complete Cu consumption by Cu-Sn IMC growth gives rise to a direct contact between solder inner layer such as Ti, Ni and Pd, and hence to possibly cause reactions between two of them. In this study, however, only for the Pd case, IMC of PdSn. was observed by Cu consumption. UBM interfacial reactions with s이der affected the adhesion strength ot s이der balls after s이der reflow and annealing treatment.

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The influence of the tidal front on primary productivity and distribution of phytoplankton in the mid-eastern coast of Yellow Sea (황해 중.동부 연안 수역의 조석전선이 식물 플랑크톤 생산력과 분포에 미치 는 영향)

  • 최중기
    • 한국해양학회지
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    • v.26 no.3
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    • pp.223-241
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    • 1991
  • In order to study the formation and structure of tidal fronts and their influence on the distribution and productivity of phytoplankton in the outer of Kyonggi Bay, analyses on the water temperature data from 1977 to 1986 and 3 surveys from 1981 to 1986 were carried out in the mid0eastern coast of the Yellow Sea. Temperature gradients and dissolved oxygen gradients were implied that the tidal fronts are formed at the outer of the Kyonggi Bay along the western side of Tae-An peninsula from spring to summer. the formations of tidal fronts in this study area influence the distribution of phytoplankton and primary productivity. The standing stocks, chlorophyll concentrations and primary productivity of phytoplankton in the frontal area are higher than those of the outer stratified waters and the inner coastal mixed waters. These high production in the frontal area are resulted from good light condition and rich nutrient within the water columns. With a boundary of frontal area, there are relatively high chlorophyll concentrations and primary productivity in the coastal mixed waters while there are low chlorophyll concentrations and relatively high primary productivity in the stratified waters. These relatively high primary productivity in the outer area are resulted from the high potential production by nanoplankton in the surface layer and the high production of tychopelagic diatoms under the thermocline with the deep transparency.

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Effect of Al Content Variation on High Temperature Gas Nitriding in 13%Cr-0.16%C Stainless Steel (13%Cr-0.17%C 스테인리스강의 고온 가스질화에 미치는 Al 함량 변화의 영향)

  • Park, B.T.;Kim, J.M.;Kang, H.J.;Kong, J.H.;Kang, C.Y.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.24 no.6
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    • pp.318-326
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    • 2011
  • This study has been performed to investigate the effect of Al addition on High Temperature Gas Nitriding (HTGN) in 13%Cr-0.16%C stainless steel with different Al contents of 0.54%, 1.76% and 2.36%, respectively. HTGN treatment was carried out at $1100^{\circ}C$ for 1 hr, 5 hrs and 10 hrs. Nitrogen-permeated surface layers showed round type carbides of $Cr_{23}C_6$ and needle type nitrides of AlN in the matrix of martensite, representing 600~700 Hv. And the thickness of the surface layer increased with increasing Al content and HTGN treatment time. The inner region that was not permeated nitrogen showed chromium carbides in the mixed phase of martensite and ferrite for the 0.53% Al alloyed steel, however chromium carbides in the matrix of ferrite single phase were shown for the steels with the addition of 1.76%Al and 2.36%Al, representing the hardness of ~200 Hv. During nitrogen permeation from surface to the interior, substitutional elements of Cr, Al and Si moved toward the surface and interstitial element of carbon also moved from interior to the surface. This movement of alloying elements leads high concentration of these elements at the outmost surface, subsequently the lowest peak of substitutional elements were shown in the vicinity of near surface. After showing the lowest peak, the high concentration region of Al and C were formed due to the continuous movement of Al toward the surface. The long discontinuous precipitates of $Cr_{23}C_6$ and AlN were formed along the outmost surface owing to the high concentration of these alloying elements.

Anatomical Characteristics of Korean Phyllostachys pubescens by Age (국내산 맹종죽의 죽령별 해부학적 특성)

  • Jeon, Woo-Seok;Byeon, Hee-Seop;Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.3
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    • pp.231-240
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    • 2018
  • Bamboo is one of the major biomass resources that have many advantages such as fast growing, easy cultivation, short rotation, and a relatively lower price. In this study, the anatomical characteristics of Moso bamboo (Phyllostachys pubescens) by age from one-year-old to five-year-old were examined by optical and scanning electron microscopy. Also, the crystalline properties such as relative crystallinity and crystallite width were investigated by an X-ray diffraction method. In one-year-old bamboo xylem, a few vascular bundles showed missing bundle sheath in near the intercellular space. Moreover, one-year-old bamboo had the shortest fiber length and the smallest values in vessel diameter, width of vascular bundle, and thickness of inner layer. One-year-old bamboo also showed the smallest values in the crystallinity and crystallite width. Near epidermis samples had longer fiber length and greater vascular bundle spacing than near pith samples. Relative crystallinity and crystallite width near the epidermis were also higher than near the pith. This study revealed significant differences in qualitative and quantitative anatomical characteristics between one-year-old and two-year- or more old Moso bamboos. It is concluded that the structural differences by bamboo age can be used to differentiate the characteristics of juvenile and mature bamboo.

Magnetism and Half-metallicity of Co2TiSn(001) Surfaces: A First-principles Study (Co2TiSn(001) 표면의 자성 및 반쪽금속성에 대한 제일원리연구)

  • Jin, Y.J.;Lee, J.I.
    • Journal of the Korean Magnetics Society
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    • v.18 no.4
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    • pp.131-135
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    • 2008
  • The electronic structures, magnetism, and half-metallicity of the full-Heusler $Co_2TiSn$(001) surfaces have been investigated by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. We have considered both of the Co atoms terminated(Co-term) and the TiSn atoms terminated(TiSn-term) surfaces. From the calculated density of states, we found that the half-metallicity was destroyed at the surface of the Co-term, while the half-metallicity was retained at the TiSn-term. For the surface of the Co-term, due to the reduced coordination number the occupied minority d-states were shifted to high energy regions and that cross the Fermi level, thus destroy the surface half-metallicity. On the other hand the surface states at the surface of the TiSn-term were located just below the Fermi level, which reduces the minority spin-gap with respect to that of the center layer. The calculated magnetic moment of the surface Co atom for the Co-term was increased by 10 % to 1.16 ${\mu}_B$ with respect to that of the inner-layers, while the magnetic moment of the subsurface Co atom in the TiSn-term has almost same value of the innerlayers(1.03 ${\mu}_B$).

Late Quaternary Seismic Stratigraphy and Sedimentation of the Southeastern Continental Shelf, Korea Strait (한국 남동해역(대한해협) 대륙붕지역의 후 제4기 탄성파 층서 및 퇴적작용)

  • Yoo Dong-Geun;Lee Chi-Won;Min Gun-Hong;Lee Ho-Young;Choi Joung-Gyu;Park Soo-Chul
    • Geophysics and Geophysical Exploration
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    • v.8 no.3
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    • pp.201-206
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    • 2005
  • Interpretation of high-resolution seismic profiles from the southeastern continental shelf of Korea reveals that the sedimentary deposits consist of seven seismic units formed during the late Quaternary. These units comprise lowstand, transgressive, and highstand systems tracts. The lowstand systems tract consists of a lowstand prograding wedge (SU1) and a mass flow deposit (SU2) including slumps and slides. The transgressive systems tract contains four seismic units: an ancient beach/shoreface deposit (SU3), a channel-fill deposit (SU4), a transgressive sand layer (SU5), and a transgressive sand ridge (SU6). The highstand systems tract consists of an inner-shelf mud deposit (SU7) derived from the Nakdong and Seomjin rivers during the last 6 ka when sea level was close to the present level.

A Study on the Appropriateness as Organic Matters Indicator and the Distribution of Chemical Oxygen Demand and Total Organic Carbon in Masan Bay, Korea (마산만 해수 중 화학적산소요구량과 총유기탄소 분포 특성 및 유기물 지표로서의 적절성 검토)

  • PARK, MI-OK;LEE, YONG-WOO;CHO, SEONG-AH;KIM, HYE-MI;PARK, JUN-KUN;KIM, SUNG-GIL;KIM, SEONG-SOO;LEE, SUK MO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.26 no.2
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    • pp.82-95
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    • 2021
  • We investigated the temporal and spatial distribution characteristics of chemical oxygen demand (COD) and total organic carbon (TOC) in all 13 locations of Masan Bay from February to November in 2015. The COD and TOC contents were high during the June-August period when the pollution load increased. In particular, the concentrations of COD and TOC were about twice as high in the surface water as in the bottom water. In spatial distribution, the COD and TOC concentrations at the inner bay were about twice as high as those of the outer bay in Masan Bay. As a result of estimating the oxidation efficiency of COD from the surface layer of Masan Bay in 2015 based on the theoretical oxygen demand (TOD), it was at the level of about 23%. Due to the low oxidation efficiency of COD, there is a risk that the organic matter in Masan Bay will be somewhat underestimated. Therefore, for quantitative analysis of organic matter, COD and TOC analyses need to be combined.