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11.
Robotica is a computer-aided design package for robotic nmanipulators developed at the Coordinated Science Laboratory at the University of Illinois at Urbana- Champaign. The package is a collection of function definitions for the Mathematica symbolic mathematics program. Robotica can be used either with an X- Windows graphical user interface (GUI) on a Sun Workstation or as an included function definition file within Mathematica. The primary feature of Robotica is the ability to compute, symbolically or numerically, the kinematic and dynamic equations of arbitrary robot systems utilizing the standard Denevit-Hartenburg (DH) kinematic convention. Robotica also provides the ability to visualize these arbitrary manipulators using the X- Windows graphical interface to the Mathematica graphics routines. The paper looks at the usage of Robotica at the Air Force Institute of Technology, comments on the features of Robotica, and needs for improvement and suggestions for future development 相似文献
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Steeds M.W. Broschat S.L. Schneider J.B. 《Electromagnetic Compatibility, IEEE Transactions on》1996,38(2):181-187
Two conformal finite-difference time-domain (FDTD) methods are considered, the contour path (CPFDTD) method of Jurgens et al. (see IEEE Trans. Antennas Propagat., vol.40, p.357, 1992) and the overlapping grid (OGFDTD) method of Yee et al. (see IEEE Trans. Antennas Propagat., vol.40, p.1068, 1992). Both TE and TM scattering from a two-dimensional (2-D), perfectly conducting circular cylinder are used to test the accuracy of the methods for curved surfaces. Also, TE and TM scattering from a 2-D, perfectly-conducting rotated square cylinder are used to test the accuracy for corners and edges. It is shown that the conformal method proposed by Yee et al. provide significant improvement in accuracy over the original FDTD algorithm for most of the geometries studied. However, implementation becomes more difficult as the geometries become more complex. The conformal method proposed by Jurgens et al. provide significant improvement in accuracy as well for most of the geometries studied. However, improvement does not occur for the TM case when the square cylinder is not aligned properly with the grid. Implementation of the CPFDTD method is relatively straightforward. For the majority of the cases studied, the OGFDTD method is more accurate than the CPFDTD method 相似文献
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A novel discontinuous buffer system for DNA sequencing based on horizontal ultrathin-layer gel electrophoresis is described. The optimized system, named unbuffered stacking gel/discontinuous borate EDTA-buffer system, is composed of a 0.5 mm thick stacking gel, where standard sequencing reactions (1 microL volume) are easily loaded, and a 50 microns ultrathin running gel, where DNA fragments are separated. The novel discontinuous buffer system allows for sample concentration and efficient injection from the stacking gel into the capillary slab gel. Increased resolution, assessed by autoradiography, can be achieved within 25 min running time already over a 10.1 cm distance from the gel slot compared to the conventional gel system. An advantage of the new system is the capacity to resolve compressions in GC-rich regions, usually causing migrating artifacts in standard gels. The described system affords a major improvement in speed, resolution and reproducibility in DNA sequencing. 相似文献
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Ravi Joshi Jörg Engstler P. Kesavan Nair Prathap Haridoss Jörg J. Schneider 《Diamond and Related Materials》2008,17(6):913-919
Carbon nanotubes (CNTs) have been synthesized using the arc discharge method with a rotating graphite disc as the cathode. Arcing was carried out in open air and without the use of catalysts. The current density was maintained constant through out the experiment, while, the rate of rotation of the cathode and atmosphere under which arcing was carried out were changed during experimentation. Characterization of the samples produced indicates that rotation of the cathode has a significant impact on the quality and yield of the process. It is proposed that rotation of the cathode drags plasma formed between two electrodes away from high temperature region. This results in a sudden quenching of the reactive plasma. The time available for nucleation and growth phenomena is significantly reduced and thus leads to the formation of highly graphitic multi walled CNTs (yield 60%) and traces of double walled CNTs. 相似文献
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With new methods for enforcing security policies comes the opportunity to formulate application-specific policies. But leveraging that flexibility might prove a difficult problem, not only in practice, but also in theory. 相似文献
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IEEE Security & Privacy's associate editor in chief discusses technology's role in identity fraud and identity theft. 相似文献