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Anticalcification Treatment of Glutaraldehyde-fixed Bovine Pericardium with Amino Acids (The Effect of Ethanol, Glutamic Acid and Homocysteic Acid Treatment) (글루타르알데하이드로 고정한 소 심낭의 아미노산을 이용한 항석회화 처리(에탄올, 글루타믹 산, 호모시스테익 산 처리의 효과))

  • Lee, Cheul;Kim, Yong-Jin;Lee, Chang-Ha;Kim, Soo-Hwan;Choi, Seung-Hwa
    • Journal of Chest Surgery
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    • v.42 no.4
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    • pp.409-417
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    • 2009
  • Background: Glutaraldehyde-fixed heterografts are prone to calcification after long-term implantation in human, and this is one of the limiting factors for the longevity of the heterografts used in cardiovascular surgery. The aim of the study was to evaluate the anticalcification effect of an ethanol and amino acids treatment on glutaraldehyde-fixed bovine pericardium. Material and Method: Bovine pericardial tissues were divided into 5 groups. Group 1 consisted of tissues fixed with glutaraldehyde, group 2 consisted of commercially available bovine pericardial valve tissues (Carpentier-Edwards PERIMOUNT), group 3 consisted of glutaraldehyde-fixed tissues treated with ethanol, group 4 consisted of glutaraldehyde-fixed tissues treated with ethanol and L-glutamic acid, and group 5 consisted of glutaraldehyde-fixed tissues treated with ethanol and homocysteic acid. The tissue microstructure was examined by light and electron microscopy. Tissue samples of each group were implanted into rat subcutaneous tissue for 3 $\sim$ 4 months and the calcium contents were measured after harvest. Result: The collagen fibers appeared to be well preserved in all the groups. The calcium contents of groups 2, 3, 4 and 5 (13.46$\pm$11.74, 0.33$\pm$0.02, 0.39$\pm$0.08 and 0.42$\pm$0.06 $\mu$g/mg, respectively) were all significantly lower than that of group 1 (149.97$\pm$28.25 $\mu$g/mg) (p<0.05). The calcium contents of groups 3, 4 and 5 were all significantly lower than that of group 2 (p<0.05). Conclusion: Treatment with ethanol alone or in combination with amino acids (L-glutamic acid or homocysteic acid) strongly prevented the calcification of glutaraldehyde-fixed bovine pericardium.

Effect of Heat Treatment Conditions on the Characteristics of Gel Made from Arrowroot Starch in Korea Cultivars (국내산 칡 전분 젤 특성에 미치는 가열처리 조건의 영향)

  • Lee, Seog-Won;Kim, Hyo-Won;Han, Sung-Hee;Rhee, Chul
    • The Korean Journal of Food And Nutrition
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    • v.22 no.3
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    • pp.387-395
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    • 2009
  • This study was conducted to investigate the effects of starch concentrations and heating conditions on the gel characteristics of arrowroot starch. Arrowroot starch gels with various pHs, and starch concentrations, were prepared using different temperatures and heating times, and then stored for 24 hrs at $4^{\circ}C$. The hardness of sample gels made at pH 2.0 and 4.0 increased as the starch concentration increased from 7% to 10%, with the maximum value of 94 N being obtained when the gel was prepared at pH 4.0 with a starch concentration of 10%. The maximum hardness of samples prepared with concentrations of starch ranging from 7~9% appeared at $80^{\circ}C$, regardless of the heating temperature and time. Furthermore, the hardness of samples prepared at greater than $100^{\circ}C$ was relatively lower than that of samples prepared at other temperatures. When a starch concentration of 8% was used, the degree of gelatinization(DR) increased as the heating temperature increased, with the maximum value of DR being about 76% at $120^{\circ}C$, regardless of heating time. After storage for 24 hrs, the hardness of samples prepared at $70^{\circ}C$, $80^{\circ}C$ and $90^{\circ}C$ appeared to decrease, while that of samples prepared at $100^{\circ}C$, $110^{\circ}C$ and $120^{\circ}C$ increased. The correlation between hardness and the degree of gelatinization or retrogradation was very high when samples were prepared at $80^{\circ}C$ with a starch concentration of 9%, as indicated by a correlation coefficient of greater than 0.95. Overall, the microstructures of freeze-dried arrowroot starch gel were composed of a continuous network of amylose and amylopectin with fragmented ghost structures in an excluded phase, but these ghost structures were more evident after storage and with increased heating temperature.

Magnetic Properties of Electroless Co-Mn-P Alloy Deposits (무전해 Co-Mn-P 합금 도금층의 자기적 특성)

  • Yun, Seong-Ryeol;Han, Seung-Hui;Kim, Chang-Uk
    • Korean Journal of Materials Research
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    • v.9 no.3
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    • pp.274-281
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    • 1999
  • Usually sputtering and electroless plating methods were used for manufacturing metal-alloy thin film magnetic memory devices. Since electroless plating method has many merits in mass production and product variety com­pared to sputtering method, many researches about electroless plating have been performed in the United State of America and Japan. However, electroless plating method has not been studied frequently in Korea. In these respects the purpose of this research is manufacturing Co-Mn-P alloy thin film on the corning glass 2948 by electroless plating method using sodium hypophosphite as a reductant, and analyzing deposition rate, alloy composition, microstructure, and magnetic characteristics at various pH's and temperatures. For Co-P alloy thin film, the reductive deposition reaction 0$\alpha$urred only in basic condition, not in acidic condition. The deposition rate increased as the pH and temperature increased, and the optimum condition was found at the pH of 10 and the temperature of $80^{\circ}C$. Also magnetic charac­teristics was found to be most excellent at the pH of 9 and the temperature of $70^{\circ}C$, resulting in the coercive force of 8700e and the squareness of 0.78. At this condition, the contents of P was 2.54% and the thickness of the film was $0.216\mu\textrm{m}$. For crystal orientation, we could not observe fcc for $\beta$-Co. On the other hand,(1010), (0002), (1011) orientation of hcp for a-Co was observed. We could confirm the formation of longitudinal magnetization from dominant (1010) and (1011) orientation of Co-P alloy. For Co-Mn-P alloy deposition, coercive force was about 1000e more than that of Co P alloy, but squareness had no difference. For crystal orientation, (l01O) and (lOll) orientation of $\alpha$-Co was dominant as same as that of Co- P alloy. Likewise we could confirm the formation of longitudinal magnetization.

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Fabrication and Characterization of $CuInSe_2$Thin Films from $In_2Se_3$ and$Cu_2Se$Precursors ($In_2Se_3$$Cu_2Se$를 이용한 $CuInSe_2$박막제조 및 특성분석)

  • Heo, Gyeong-Jae;Gwon, Se-Han;Song, Jin-Su;An, Byeong-Tae
    • Korean Journal of Materials Research
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    • v.5 no.8
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    • pp.988-996
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    • 1995
  • CuInSe$_2$this films as a light absorber layer were fabricated by vacuum evaporation using In$_2$Se$_3$and Cu$_2$Se precursors and their properties were analyzed. Indium selenide films of 0.5${\mu}{\textrm}{m}$ thickness were first deposited by vacuum evaporation of In$_2$Se$_3$ on a Corning 7059 glass substrate. The films deposited at suscepor temperature of 40$0^{\circ}C$ showed a flat surface morphology with densely Packed grain structure. CuInSe$_2$films directly formed by evaporating Cu$_2$Se on the predeposited In$_2$Se$_2$films also showed a very flat surface when the susceptor temperature was $700^{\circ}C$. Cu$_2$Se, a second phase in the CuInSe$_2$film, was removed by evaporating additional In$_2$Se$_3$on the CuInSe$_2$film at $700^{\circ}C$. The grain size of 1.2${\mu}{\textrm}{m}$ thick CuInSe$_2$, film was about 2${\mu}{\textrm}{m}$ and the film had a (112) preferred orientation. As the amount of deposited In$_2$Se$_3$increased, the electrical resistivity of CuInSe$_2$films increased because of the decrease of hole concentration. But the optical band gap was almost constant at the value of 1.04eV, The CuInSe$_2$film grown on a Mo/glass substrate had a similar smooth microstructure compared to that on a glass substrate. A solar cell with ZnO/CdS/CuInSe$_2$/Mo structure may be realized based on the above CuInSe$_2$films.

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Metamorphic P-T Paths from Devonian Pelitic Schists from the Pelham Dome, Massachusetts, USA (뉴잉글랜드 펠암돔 주변부 데본기 변성 이질암의 변성 온도-압력 경로)

  • 김형수
    • The Journal of the Petrological Society of Korea
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    • v.9 no.4
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    • pp.211-237
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    • 2000
  • Major element zoning has been analyzed in garnet porphroblasts obtained from the Grt-St and Ky-Grt-St grade assemblages in Zones I on the northern flank of the Pelham Dome, north central Massachusetts. These porphyroblasts grew during multiple phases of deformation and meta-morphism revealed by the inclusion trail geometry plus the chemical zoning patterns within garnet porphyroblasts. Unusual zoning patterns, including zoning reversals and gradient changes in XMn, zlgzag patterns in Fe/(Fe +Mg) and staircase-shaped patterns in XCa, are coincident with textural truncations and other changes in microstructure within the garnet porphrublasts. Chemical variations in plagioclase, biotite, muscovite and staurolite combined with inclusion trail geometry and petrography reveal that the garnet zoning patterns are modified by combinations of the following. (1) Uni-and divariant reactions involving garnet consumption(Grt+ Chl+Ms=St+Bt+Qtz + $H_2$O) and production(St+Ms + Qtz= Bt+ Grt +A1$_2$$SiO_{5}$ + $H_2$O). (2) Deformation induced episudic ionit dissolution, preferential diffusion and re-distribution during foliation development. (3) P-T changes during growth of the porphyroblasts. The P-T paths combined with petrographic and inclusion trail morphology observations consist of two pattens; (1) heating/compression during NW-SE shortening; and (2) decompression with cooling during NNW-SSE shortening. Based on temperature-time(T-t) geochronological data and late-Paleozoic tectonic model, Alleghanian metamorphism, which is the result of heterogeneous shearing concentrated along the boundary between the Abalone Terrane(Pelham dome) and cover rocks(Bronson Hill Terrane), has produced Ky-St-Ms mineral assemblage during Pennsylvanian(290-300 Ma) in Shutesbury area. However, temperature of alleghanian metamorphism was not high enough to form garnet and staurolite in the Northfiled syncline area. Alleghanian metamorphism has affected only the matrix due to heterogeneous shearing in the study area.

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Preparation of $WO_3/TiO_2$ and $V_2O_5/TiO_2$ powders and their catalytic performances in the SCR of $NO_x$ ($WO_3/TiO_2$$V_2O_5/TiO_2$ 분말의 합성 및 $NO_x$ 제거 SCR특성)

  • Lee, Tae-Suk;Lee, In-Gyu;Lee, Byeong-Woo;Shin, Dong-Woo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.5
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    • pp.216-221
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    • 2006
  • An investigation of the influence of $WO_3$ and $V_2O_5$ catalysts on the microstructure, phase formation and selective catalytic reduction (SCR) efficiency of the synthesized SCR powders has been carried out. A commercial anatase-$TiO_2$ was used as the catalysts support. For $WO_3(10wt%)/TiO_2$, the W loading to the $TiO_2$ support led to the lower in anatase to rutile transition temperature from $1200^{\circ}C$ of $TiO_2$ support to ${\sim}900^{\circ}C$. The transition temperature was also lowered to below $650^{\circ}C$ in the $V_2O_5$(5 and 10 wt%) added composition. The $WO_3(10wt%)/TiO_2$ SCR powder obtained at $450^{\circ}C$ showed near 100% of $NO_x$ conversion efficiency at $350{\sim}400^{\circ}C$ and for the powder prepared at $650^{\circ}C$ the same efficiency was achieved in wider temperature range $300{\sim}400^{\circ}C$. The highest $NO_x$ conversion efficiency of 100% was obtained in the $V_2O_5(5wt%)/TiO_2$ SCR composition calcined at $650^{\circ}C$ in the relatively wider temperature range $250{\sim}350^{\circ}C$, while the catalytic efficiency considerably decreased for the $V_2O_5(10wt%)/TiO_2$. The lowered conversion efficiency of $NO_x$ observed in the $V_2O_5(10wt%)/TiO_2$ composition calcined at $650^{\circ}C$ was considered to be correlated with the lowered surface area resulting from the increased crystallite growth by highly reactive vanadium loading.

A Transmission Electron Microscopy Study on the Crystallization Behavior of In-Sb-Te Thin Films (In-Sb-Te 박막의 결정화 거동에 관한 투과전자현미경 연구)

  • Kim, Chung-Soo;Kim, Eun-Tae;Lee, Jeong-Yong;Kim, Yong-Tae
    • Applied Microscopy
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    • v.38 no.4
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    • pp.279-284
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    • 2008
  • The phase change materials have been extensively used as an optical rewritable data storage media utilizing their phase change properties. Recently, the phase change materials have been spotlighted for the application of non-volatile memory device, such as the phase change random access memory. In this work, we have investigated the crystallization behavior and microstructure analysis of In-Sb-Te (IST) thin films deposited by RF magnetron sputtering. Transmission electron microscopy measurement was carried out after the annealing at $300^{\circ}C$, $350^{\circ}C$, $400^{\circ}C$ and $450^{\circ}C$ for 5 min. It was observed that InSb phases change into $In_3SbTe_2$ phases and InTe phases as the temperature increases. It was found that the thickness of thin films was decreased and the grain size was increased by the bright field transmission electron microscopy (BF TEM) images and the selected area electron diffraction (SAED) patterns. In a high resolution transmission electron microscopy (HRTEM) study, it shows that $350^{\circ}C$-annealed InSb phases have {111} facet because the surface energy of a {111} close-packed plane is the lowest in FCC crystals. When the film was heated up to $400^{\circ}C$, $In_3SbTe_2$ grains have coherent micro-twins with {111} mirror plane, and they are healed annealing at $450^{\circ}C$. From the HRTEM, InTe phase separation was occurred in this stage. It can be found that $In_3SbTe_2$ forms in the crystallization process as composition of the film near stoichiometric composition, while InTe phase separation may take place as the composition deviates from $In_3SbTe_2$.

Study on the Manufacturing techniques & Conservation of Iron Pot from Cheonmachong Ancient Tomb (천마총 출토 철부(鐵釜)의 제작기법 및 보존처리)

  • Lee, Seung Ryul;Shin, Yong Bi;Jung, Won Seob
    • Journal of Conservation Science
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    • v.30 no.3
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    • pp.263-275
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    • 2014
  • It's shown how to proceed the study on Manufacturing techniques & Conservation to the Iron Pot from Cheonmachong Ancient Tomb(the 155th Tomb in Hwangnam-dong). In order to investigate manufacturing techniques of the Iron Pot, some parts of the relic were gathered. After mounting, polishing and etching on the relic, analyzing the metal microstructure was conducted. Also it's conducted a SEM-EDS analysis on the nonmetallic inclusion. White iron structure was observed in the metallurgical structure inspection, SEM-EDS analysis. It seems to be dried slowly at room temperature after casting, doesn't look as particular heat treatment to improve brittleness. It is estimated that it's as the handle seam side were verified about 3cm inch wide, 1.5 thick in center of body, so 2 separate half-completed products was cast with width-type mould. The manufacturing techniques Using white cast iron structure, width-type mould are observable to the Iron Pot excavated from Sikrichong Ancient Tomb & Hwangnamdaechong grand Ancient Tomb around those were constructed the same time. It's able to recognize that it's almost identical manufacturing techniques at that time. Conservation is generically following those are survey of pretreatment, foreign material removal, stabilization, restoration and color matching in the order. cleaning & drying were added to the process as occasion demands. The strengthening treatment were difficult with artifact's volume, low concentration Paraloid NAD-10 solution was spread two or three times with a brush, surface hardening also came up with 15wt% Paraloid NAD-10 solution after the conservation was complete. There were connection & restoration for the restoration to the damage after modeling forms that it's similar to damaged parts by using the Fiber Reinforced Plastic resins(POLYCOAT FH-245, mold laminated type). Throughout this research, capitalizing on accumulations of measurements about the production technique of Iron Pot in the time of the fifth and 6th centuries is no less important than the Iron artifact's conservation for a better study in the future.

Velocity-effective stress response of $CO_2$-saturated sandstones ($CO_2$로 포화된 사암의 속도-유효응력 반응)

  • Siggins, Anthony F.
    • Geophysics and Geophysical Exploration
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    • v.9 no.1
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    • pp.60-66
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    • 2006
  • Three differing sandstones, two synthetic and one field sample, have been tested ultrasonically under a range of confining pressures and pore pressures representative of in-situ reservoir pressures. These sandstones include: a synthetic sandstone with calcite intergranular cement produced using the CSIRO Calcite In-situ Precipitation Process (CIPS); a synthetic sandstone with silica intergranular cement; and a core sample from the Otway Basin Waarre Formation, Boggy Creek 1 well, from the target lithology for a trial $CO_2$ pilot project. Initial testing was carried on the cores at "room-dried" conditions, with confining pressures up to 65 MPa in steps of 5 MPa. All cores were then flooded with $CO_2$, initially in the gas phase at 6 MPa, $22^{\circ}C$, then with liquid-phase $CO_2$ at a temperature of $22^{\circ}C$ and pressures from 7 MPa to 17 MPa in steps of 5 MPa. Confining pressures varied from 10 MPa to 65 MPa. Ultrasonic waveforms for both P- and S-waves were recorded at each effective pressure increment. Velocity versus effective pressure responses were calculated from the experimental data for both P- and S-waves. Attenuations $(1/Q_p)$ were calculated from the waveform data using spectral ratio methods. Theoretical calculations of velocity as a function of effective pressure for each sandstone were made using the $CO_2$ pressure-density and $CO_2$ bulk modulus-pressure phase diagrams and Gassmann effective medium theory. Flooding the cores with gaseous phase $CO_2$ produced negligible change in velocity-effective stress relationships compared to the dry state (air saturated). Flooding with liquid-phase $CO_2$ at various pore pressures lowered velocities by approximately 8% on average compared to the air-saturated state. Attenuations increased with liquid-phase $CO_2$ flooding compared to the air-saturated case. Experimental data agreed with the Gassmann calculations at high effective pressures. The "critical" effective pressure, at which agreement with theory occurred, varied with sandstone type. Discrepancies are thought to be due to differing micro-crack populations in the microstructure of each sandstone type. The agreement with theory at high effective pressures is significant and gives some confidence in predicting seismic behaviour under field conditions when $CO_2$ is injected.

Development of Vacuum Puffing Machine for Non-deep Fried Yukwa and Its Puffing Characteristics by Process Variables (비유탕 유과 제조를 위한 진공팽화기의 개발 및 공정변수에 따른 유과의 팽화특성)

  • Yu, Je-Hyeok;Ryu, Gi-Hyung
    • Food Engineering Progress
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    • v.14 no.3
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    • pp.193-201
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    • 2010
  • The aim of this study was to analyse the quality of Yukwa puffed by using a vacuum puffing machine and compare to deep-fried Yukwa. The effect of vacuum puffing condition including heating temperature(100-${160^{\circ}C}$), preheating time(0-8 min) and vacuum puffing time(5-20 min) on physical and microstructure characteristics of the Yukwa was investigated. Vacuum puffed Yukwa at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 10 min puffing time had highest value in volumetric expansion ratio(10.04) and lowest value in bulk density(0.15 g/$cm^{3}$). The breaking strength showed the lowest value of 140 g/$cm^{3}$ in vacuum puffing Yukwa at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 15 min puffing time. The Yukwa puffed with the vacuum puffing machine at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 15 min puffing time had the higher value of bulk density and the lower value of volumetric expansion ratio than those of deep-fried Yukwa. Increasing preheating time and vacuum puffing time caused an increase in white and an decrease in yellowness. The vacuum-puffed Yukwa exhibited smaller and uniform cell structure, while deep-fried Yukwa exhibited apparently in larger pores inside and smaller pores near the surface layer. The optimum condition of vacuum puffing machine for the production of vacuum-puffing Yukwa was ${120^{\circ}C}$ heating temperature, 4 min preheating time and 5 min puffing time.