A set of runs were performed on the catalytic and thermal cracking of the tars present fn the gasifier off-gas stream; the cracking referred to here Js essentially hydrocracking, in view of the considerable amount of hydrogen being present in the gas stream. The catalyst evaluated for tar cracking was a commercial cobalt-molybdenum catalyst, suppported on γ-Al2O3(Katalco-477). It was observed that there was a decrease in the amount of tar obtained with the cracking unit on-line with the gasifier; the tars were cracked to gaseous products in the presence of catalyst. Furthermore, it appeared that higher ring structures were transformed to less heavier components; thus cracking could become beneficial in downstream processing of the gas stream coming out of a gasifier. 相似文献
The red emitting Ca0.5Gd(WO4)2:Eu3+ was synthesized by a solid-state reaction method. X-ray diffraction patterns were used to characterize crystal structure as well as phase purity. The results suggest that the as synthesized powder phosphor possess scheelite crystal structure with tetragonal symmetry along with the space group of I41/a. SEM studies reveal that the as synthesized sample show polyhedral morphology with particle size of 5.5 µm. Photoluminescence excitation spectrum depicts that a broad band (from 200 to 300 nm) centered at 242 nm is attributed to the ligand to metal charge transfer transition of WO42? and three intense with sharp absorption bands (observed at 394, 464 and 535 nm) are designated as f–f electronic transitions of Eu3+. Photoluminescence emission studies indicate that, under 394 nm UV excitation, a hypersensitive red emission was observed at 617 nm due to the transition from upper 5D0 level to the 7F2 lower level of Eu3+ ion. The spectroscopic behaviour of the as synthesized phosphor Ca0.5Gd(WO4)2:Eu3+ was determined using Judd–Ofelt theory. The CIE color coordinates, colour correlated temperature and luminous efficacies of radiation were estimated. The as obtained results indicating that the Ca0.5Gd(WO4)2:Eu3+ red phosphor is most suitable for solid state lighting applications. 相似文献
In this paper, we show the tracking performance of a rotary piezoelectric motor based hard disk drive actuator. The actuator is built and modeled for positioning servo in disk drive systems. The Piezo motor replaces the voice-coil-motor based primary actuation. Simulation and experimental results for its servo system proves that it can help to achieve track density of more than 1000?KTPI. 相似文献
Copper films containing various amounts of insoluble Nb (up to 24.7 at.%) were prepared by r.f. magnetron sputtering. The crystallography and microstructure of the films were investigated for as-deposited and annealed Cu(Nb) thin films. Cu(Nb) thin films are found to consist of non-equilibrium supersaturated solid solution of Nb in Cu with a nanocrystalline microstructure. X-ray diffraction and scanning electron microscope analyses revealed a reduction in the grain sizes of the films with increasing Nb content in the films leading to a grain refinement. The electrical resistivity of as-deposited and annealed Cu(Nb) thin films is found to be low for an Nb content 2.7 at.%. Significant drops in the resistivity were observed for the high Nb contents after annealing at 530 °C which may be due to grain growth and formation of Nb-bearing phase in the film. Microhardness of the films was found to increase with the Nb concentration due to the combined effects of grain refinement and the solute strengthening of Nb. 相似文献
Eigendecomposition-based techniques are popular for a number of computer vision problems, e.g., object and pose estimation,
because they are purely appearance based and they require few on-line computations. Unfortunately, they also typically require
an unobstructed view of the object whose pose is being detected. The presence of occlusion and background clutter precludes
the use of the normalizations that are typically applied and significantly alters the appearance of the object under detection.
This work presents an algorithm that is based on applying eigendecomposition to a quadtree representation of the image dataset
used to describe the appearance of an object. This allows decisions concerning the pose of an object to be based on only those
portions of the image in which the algorithm has determined that the object is not occluded. The accuracy and computational
efficiency of the proposed approach is evaluated on 16 different objects with up to 50% of the object being occluded and on
images of ships in a dockyard.
Anthony A. MaciejewskiEmail:
Chu-Yin Chang
received the B.S. degree in mechanical engineering from National Central University, Chung-Li, Taiwan, ROC, in 1988, the M.S.
degree in electrical engineering from the University of California, Davis, in 1993, and the Ph.D. degree in electrical and
computer engineering from Purdue University, West Lafayette, in 1999. From 1999--2002, he was a Machine Vision Systems Engineer
with Semiconductor Technologies and Instruments, Inc., Plano, TX. He is currently the Vice President of Energid Technologies,
Cambridge, MA, USA. His research interests include computer vision, computer graphics, and robotics.
Anthony A. Maciejewski
received the BSEE, M.S., and Ph.D. degrees from Ohio State University in 1982, 1984, and 1987. From 1988 to 2001, he was a
professor of Electrical and Computer Engineering at Purdue University, West Lafayette. He is currently the Department Head
of Electrical and Computer Engineering at Colorado State University. He is a Fellow of the IEEE. A complete vita is available
at:
Venkataramanan Balakrishnan
is Professor and Associate Head of Electrical and Computer Engineering at Purdue University, West Lafayette, Indiana. He received
the B.Tech degree in electronics and communication and the President of India Gold Medal from the Indian Institute of Technology,
Madras, in 1985. He then attended Stanford University, where he received the M.S. degree in statistics and the Ph.D. degree
in electrical engineering in 1992. He joined Purdue University in 1994 after post-doctoral research at Stanford, CalTech and
the University of Maryland. His primary research interests are in convex optimization and large-scale numerical algebra, applied
to engineering problems.
Rodney G. Roberts
received B.S. degrees in Electrical Engineering and Mathematics from Rose-Hulman Institute of Technology in 1987 and an MSEE
and Ph.D. in Electrical Engineering from Purdue University in 1988 and 1992, respectively. From 1992 until 1994, he was a
National Research Council Fellow at Wright Patterson Air Force Base in Dayton, Ohio. Since 1994 he has been at the Florida
A&M University---Florida State University College of Engineering where he is currently a Professor of Electrical and Computer
Engineering. His research interests are in the areas of robotics and image processing.
Kishor Saitwal
received the Bachelor of Engineering (B.E.) degree in Instrumentation and Controls from Vishwakarma Institute of Technology,
Pune, India, in 1998. He was ranked Third in the Pune University and was recipient of National Talent Search scholarship.
He received the M.S. and Ph.D. degrees from the Electrical and Computer Engineering department, Colorado State University,
Fort Collins, in 2001 and 2006, respectively. He is currently with Behavioral Recognition Systems, Inc. performing research
in computer aided video surveillance systems. His research interests include image/video processing, computer vision, and
robotics.
相似文献
A pressurized melt gyration process has been used for the first time to generate poly(ε‐caprolactone) (PCL) fibers. Gyration speed, working pressure, and melt temperature are varied and these parameters influence the fiber diameter and the temperature enabled changing the surface morphology of the fibers. Two types of nonwoven PCL fiber constructs are prepared. First, Ag‐doped PCL is studied for antibacterial activity using Gram‐negative Escherichia coli and Pseudomonas aeruginosa microorganisms. The melt temperature used to make these constructs significantly influences antibacterial activity. Neat PCL nonwoven scaffolds are also prepared and their potential for application in muscular tissue engineering is studied with myoblast cells. Results show significant cell attachment, growth, and proliferation of cells on the scaffolds.