1,721,134 research outputs found
Development of a biomechanical model of the human body in a sitting posture with vibration transmissibility in the vertical direction
No full textThis study developed a biomechanical model of the human body for evaluating the vibration transmissibility and dynamic response to vertical vibrations in sitting posture. The biomechanical model consists of several lumped masses connected by linear spring and dampers. This model was selected from eight structural model after fitting measured data of apparent mass, vertical and rotational vibration transmissibilities to the head of five individuals on a vertical exciter vibrating under random signals. The proposed model describes the experimental data much better than the Matsumoto-Griffin model. Relevance to industry: The mechanical response of human body can be predicted well using our biomechanical model in vibrating environment such as in the driving vehicle. This model will help in ride quality simulation and designing vibration isolator such as seat. (c) 2005 Elsevier B.V. All rights reserved
A transmission electron microscopy study on the atomic arrangement and grain growth of hexagonal structured Ge2Sb2Te5
No full textThe atomic arrangement and grain growth of the hexagonal structured Ge2Sb2Te5 were investigated by a transmission electron microscopy study. Unlike the isotropic crystallization of face-centered-cubic (fcc) structured Ge2Sb2Te5, the hexagonal structured Ge2Sb2Te5 grain was preferably grown to a large degree with a specific direction. As a result, we have revealed that the grain growth occurred parallel to the (0001) plane, and identified the atomic arrangement of the hexagonal structured Ge2Sb2Te5 having nine cyclic layers by analyzing the high-resolution transmission electron microscopy images and simulated images obtained in the direction of < 1120 > zone axis. (c) 2006 Elsevier B.V. All rights reserved
Formation of Y2O3 interface layer in a YMnO3/Si ferroelectric gate structure
Full text linkDuring the crystallization of amorphous YMnO3 thin film on Si (100) at 870 degreesC in a dry O-2 ambient, a nanoprecipitate layer was found between the YMnO3 and the Si substrate. Lattice image processing as well as high-resolution transmission electron microscopy showed that the nanoprecipitate layer was a cubic Y2O3 phase. Also, it showed that a native oxide was consumed by the reaction with the Y atoms. This [111] Y2O3 layer exhibited a local epitaxial relationship to the c-axis oriented (0001) YMnO3. The formation of Y2O3 phase and the consumption of native oxide at the YMnO3/Si interface are due to the Y atom which is better than Mn in its ability to oxidize during heat treatment in O-2 ambient. (C) 2000 American Institute of Physics. [S0003-6951(00)04550-2]
High-resolution transmission electron microscopy study on the solid-phase crystallization of amorphous SrBi2Ta2O9 thin films on Si
No full textDuring the solid-phase crystallization of amorphous SrBi2Ta2O9 (SBT) thin films, the grains grew preferentially to the [1 1 0] direction forming elliptical grains. The origin of the [1 1 0]-oriented grain growth is due to the highest ionic packing (0 0 1) SET plane which includes TaO6 octahedra, and the nearest bonding direction of TaO6 octahedra in SBT plane is the [1 1 0] direction. High-resolution transmission electron microscopy acid image computer simulation indicate that antiphase boundary enhances elliptical grain growth between the amorphous matrix and the crystalline SET grain. The formation of a stacking fault results in an antiphase boundary making an atomic step of {0 0 1} planes at the amorphous/crystalline interface. At that interface, a corner of the antiphase boundary acts as preferable nucleation sites by providing an atomic step of {0 0 1} planes and enhances elliptical grain growth in the [1 1 0] direction on {0 0 1} planes. (C) 2001 Elsevier Science B.V. All rights reserved
Preferential grain growth in the solid-phase crystallization of amorphous SrB2TaO9 thin films prepared by metal-organic decomposition
No full textWe studied the crystallization process of amorphous SrBi2Ta2O9 (SBT) thin films by transmission electron microscopy. The amorphous SET films were prepared by the metal-organic decomposition method and were heat-treated at 800 degrees C in a dry O-2 ambient. Through a (001) projection, a circular grain was formed showing no preferential orientation of SET grain. On the other hand, through a (110) projection, an elliptical nucleus oriented to another (110) direction was formed. Grain with another orientation also offered evidence of 110-preferred growth. The (110)-preferred growth can be explained by the fact that the highest ionic packing plane is the (001) plane including TaO6 octahedra and the nearest bonding direction of the TaO6 octahedra in an SET structure is the (110) direction
Surface energy and the equilibrium shape of hexagonal structured Ge2Sb2Te5 grain
Full text linkSurface energy and the equilibrium shape of hexagonal structured grain in Ge2Sb2Te5 were investigated by a transmission electron microscopy (TEM) study. As a result, we have found that the equilibrium shape of hexagonal structured Ge2Sb2Te5 is a lengthened shape with (0001) plane at the major axis, which was experimentally revealed by TEM images. The hexagonal structured Ge2Sb2Te5 grain has low surface energy in {0001}, {1 (1) over bar 03}, and {(1) over bar 106} planes which have no additional broken bonds from the atoms on the steps. Therefore, it is strongly facetted by the plane having low surface energy, thus, becoming an equilibrium shape. (c) 2006 American Institute of Physics
Characterization on Structural properties of Ge-Bi-Te ternary eutectic phase for PRAM application
No full textSENSITIVITY ANALYSIS OF ION-IMPLANTED SILICON-WAFERS AFTER RAPID THERMAL ANNEALING
No full textIn this study, we have investigated sensitivities of the ion implanted silicon wafers processed by rapid thermal annealing (RTA), which can reveal the variation of sheet resistance as a function of annealing temperature as well as implantation parameters. All the wafers were sequentially implanted by the arsenic or phosphorous implantations at 40, 80, and 100 keV with the dose level of 10(14) to 2 x 10(16) ions/cm(2). Rapid thermal annealing was carried out for 10 s by the infrared irradiation at a temperature between 850 and 1150 degrees C in the nitrogen ambient. The activated wafer was characterized by the measurements of the sheet resistance and its uniformity mapping. The values of sensitivities are determined from the curve fitting of the experimental data to the fitting equation of col relation between the sheet resistance and process variables. From the sensitivity values and the deviation of sheet resistance, the optimum process conditions minimizing the effects of straggle in process parameters are obtained. As a result, a strong dependence of the sensitivity on the process variables, especially annealing temperatures and dose levels is also found. From the sensitivity analysis of the 10 s RTA process, the optimum values for the implant dose and annealing temperature are found to be in the range of 10(15) ions/cm(2) and 1050-1100 degrees C, respectively. The sensitivity analysis of sheet resistance will provide valuable data for accurate activation process, offering a guideline for dose monitoring and calibration of ion implantation process
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