• 한국축산식품학회지
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• 제24권2호
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• pp.108-114
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• 2004

본 연구는 버크셔종 돼지의 출하체중과 성별에 따른 도체 및 육질 비교를 위해 실시하였다. 첨단양돈연구소에서 사육한 178-183일령 흑돼지(버어크셔) 72두를 공시하여 출하체중과 성별에 따라 95-104kg, 105-110kg 및 111-120kg으로 분리하여 조사하였다. 경남 김해시 어방동 소재 부경양돈 농협 도축장으로 수송하여 관행적인 방법으로 도축 후 도체 특성을 조사하였으며, 육질시험은 도축하여 24시간 냉각한 다음 등심부위(longissimus dorsi)를 공시하여 조사하였다. 출하체중이111-120kg 돼지가 95-104kg과 105-110kg 돼지보다 도체중과 등지방 두께는 증가하였고, 등급은 출하체중이 105-110kg과 111-120kg인 돼지가 A, B등급에 가까운 좋은 등급을 받았지만, 95-104kg인 돼지는 B, C 등급에다(p＜0.05). 돈육 p $H_{u}$, 육즙손실 및 가열감량은 출하체중과 성별에 따라 유사하였으며, 수퇘지가 암퇘지에 비해 전단력이 높았다.(p＜0.05). 돈육의 육색은 출하체중과 성별에 따라 유사한 경향이었다. 총 육색소 함량은 출하체중이 95-104kg인 암퇘지와 111-120kg인 수퇘지가 다른 출하체중과 성별보다 높았다. 조직특성은 출하체중에 따라 유사한 경향이었고, 미경산 암퇘지가 수퇘지에 비해 탄력성과 파쇄성이 높았다. 이상의 연구에서, 도체특성(도체중과 등지방두께)은 출하 무게와 성별에 따라 영향을 받았고, 암퇘지육은 수퇘지에 비해 전단력값과 조직특성이 향상되었다.다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.71-74
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• 1998

$Er^{3+}$ doped $NdF_{3}$ single crystalline thin films with smooth, microcrack-free, and high-crystalline quality were grown on $CaF_{2}(111)$ substrate at $500^{\circ}C$by molecular beem epitaxy(MBE). The relation-ship between subcell and supercell showing the reconstructed $3^{1/2} \times 3^{1/2}$ structure was studied by reflection high-energy electron diffraction(RHEED) investigation. The film surface and the growth mode were examined in studied by RHEED patterns and atomic force microscope(AFM) images ex situ. The crystallinity of film and the lattice mismatch between $NdF_{3}Er}^{3+}(0002)$ film and $CaF_{2}(111)$ substrate depending in the $Er^{3+}$ concentration were investigated by X-ray rocking curve analysis.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.143-148
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• 1995

Ketene (CH2CO) adsorption on Ag(111) has been studied in ultrahigh vacuum using electron energy loss spectroscopy and temperature programmed desorption. Ketene adsorbs molecularly on Ag(111) at temperatures below 126 K. The coverage increases linearly with exposure until saturation. No multilayer formation and no shift in desorption temperature with coverage were observed, indicating a lack of attractive interaction between adsorbate molecules. The desorption activation energy is estimated to be 7.8 kcal/mol by assuming first order kinetics and a pre-exponential factor of 1013 sec-1. The adsorption geometry of ketene on the surface is determined from the relative intensities of the vibrational energy loss peaks. The CCO axis of CH2CO is found to be almost parallel to (∼4°away from) the surface and the molecular plane is almost perpendicular to the surface (∼3°tilt).

• Bulletin of the Korean Chemical Society
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• 제22권3호
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• pp.267-270
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• 2001

The adsorption of chlorine on a Pt(111) surface at 90 K has been studied using scanning tunneling microscopy (STM) in ultra-high vacuum environments. The adsorbed chlorine atoms give rise to two different ordered structures, (3${\times}$3)-Cl and c(4${\times}$2)- Cl, depending on the coverage. It has been determined from the STM image that the absolute coverage of (3${\times}$3)-Cl structure is 0.44, which is not in agreement with coverage calibrated by a low energy electron diffraction technique together with an Auger electron spectrometer and a thermal desorption spectrometer. The Cl atoms bound to on-top sites at the Pt(111)(3${\times}$3)-Cl surface appeared to effectively perturb the density of states of Pt atoms, as compared with that bound to bridging sites. The other ordered structure, c(4${\times}$2)-Cl, with small domain sizes, consists of both on-top and bridge-bonded species with a saturation coverage of 0.5.

• 한국산업융합학회 논문집
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• 제7권4호
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• pp.349-354
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• 2004

The growth mode of the Si layers which were grown on Si(111) by using Ag as surfactant were investigated by intensity oscillations of the RHEED specular spot at the different temperatures. we found that the introduction of Ag as the surfactant alters the growth mode from a three-dimensional clustering mechanism to a two-dimensional layer-by-layer growth. In the growth of Si layers on Si(111) with a surfactant Ag, At $450^{\circ}C$, RHEED intensity oscillation was very stable and periodic from early stage of deposition to 32 ML. RHEED patterns during homoepitaxial growth at $450^{\circ}C$ was changed from $7{\times}7$ structure into ${\sqrt{3}}{\times}{\sqrt{3}}$ structures. Since the ${\sqrt{3}}{\times}{\sqrt{3}}$ structure include no stacking fault, the stacking fault layer seems to be reconstructed into normal stacking one at transition from the $7{\times}7$ structure to a ${\sqrt{3}}{\times}{\sqrt{3}}$ one. We also found that the number of the intensity oscillation of the specular spot for Si growth with a surfactant Ag was more than for Si growth without a surfactant. This result may be explained that the activation energy decrease for the surface diffusion of Si atoms due to segregation of the surfactant toward the growing surface.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1559-1563
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• 2011

Thermal hydrogenation of phenylacetylene (PA, $C_8H_6$) to styrene ($C_8H_8$) on pre-$C_xH_y$- and C-covered Cu(111) single crystal substrates has been studied using temperature-programmed desorption (TPD) mass spectrometry. Chemisorbed PA with an acetylene group has been proved to be associated with hydrogen of pre-adsorbed $C_xH_y$ to form styrene (104 amu) on Cu surface. For the parent (PA) mass (102 amu) TPD profile, the TPD peaks at 360 K and 410 K are assigned to chemisorbed vertically aligned PA and flat-lying cross-bridged PA, respectively (J. Phys. Chem. C 2007, 111, 5101). The relative $I_{360K}/I_{410K}$ TPD ratio dramatically increases with increasing pre-adsorbed $C_xH_y$ before dosing PA, while the ratio does not increase for pre-C-covered surface. For PA on pre-$C_xH_y$-covered Cu(111) surface, styrene desorption is enhanced relative to the parent PA desorption, while styrene formation is dramatically quenched on pre-C-covered (lack of adsorbed hydrogen nearby) surface. It appears that only cross-bridged PA associates with adsorbed hydrogen to form styrene that promptly desorbs at 410 K, while vertically aligned PA is less likely to participate in forming styrene.

• Journal of Korean Vacuum Science & Technology
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• 제1권1호
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• pp.38-44
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• 1997

Epitaxial growth of SiC films on Si(111) substrates without carbonization was carried out n the temperature range of 900-100$0^{\circ}C$ under high vacuum conditions by single source chemical vapor deposition (CVD) of 1,3-disilabutane (H$_3$SiCH$_2$SiH$_2$$CH_3$). The monocrystalline nature of the films was confirmed by XRD, RHEED and cross-sectional TED. Cross-sectional TEM image indicated that no void exists and the boundary is clear and smooth at the SiC-Si(111) interface. RBS and AES analyses also showed that the films are stoichiometric and homogeneous in depth, From the results, this single source growth techniqe of using 1,3-disilabutane has been found suitable and effective for epitaxial growth of stoichiometric SiC on Si(111) without carbonization at temperatures below 100$0^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제30권6호
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• pp.1309-1312
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• 2009

Surface potential and growth processes of hexadecanethiol (HDT) self-assembled monolayers (SAMs) on Au(111) surfaces were examined by Kelvin probe method and scanning tunneling microscopy. It was found that surface potential strongly depends on surface structure of HDT SAMs. The surface potential shift for the striped phase of HDT SAMs chemisorbed on Au(111) surface was +0.45 eV, which was nearly the same as that of the flat-lying hexadecane layer physisorbed on Au(111) surface. This result indicates that the interfacial dipole layer induced by adsorption of alkyl chains is a main contributor to the surface potential change. In the densely-packed HDT monolayer, further change of the surface potential was observed, suggesting that the dipole moment of the alkanethiol molecules is an origin of the surface potential change. These results indicate that the work function of a metal electrode can be modified by controlling the molecular orientation of an adsorbed molecule.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1383-1387
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• 2013

The surface structure and electrochemical behavior of self-assembled monolayers (SAMs) prepared from benzenethiol (BT), cyclohexanethiol (CHT), and cyclopentanethiol (CPT) on Au(111) surface were examined by scanning tunneling microscopy (STM) and cyclic voltammetry (CV) to understand the influence of thiol molecular backbone structure on the formation and reductive desorption behavior of SAMs. STM imaging showed that BT and CPT SAMs on Au(111) surface formed at room temperature were mainly composed of disordered domains, whereas CHT SAMs were composed of well-ordered domains with three orientations. From these STM results, we suggest that molecule-substrate interaction is a key parameter for determining the structural order and disorder of simple aromatic and alicyclic thiol SAMs on Au(111). In addition, the reductive desorption peak potential for BT SAMs with aromatic rings was observed at a less negative potential of -566 mV compared to CHT SAMs (-779 mV) or CPT SAMs (-775 mV) with aliphatic cyclic rings. This reductive desorption behavior for BT SAMs is due to the presence of p-orbitals on the aromatic rings, which promote facile electron transfer from the Au electrode to BT as compared to CHT and CPT. We also confirmed that the reductive desorption behavior for simple alicyclic thiol SAMs such as CHT and CPT SAMs on Au electrodes was not significantly influenced by the degree of structural order.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.111-114
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• 2000

Growth characteristics and microstructure of AlN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the microstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.