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951.
The gates of GaAs MESFETS rely on the formation of a Schottky diode between the semiconductor surface and a deposited metal and so are extremely sensitive to the nature of this interface. For this reason an investigation of surface damage and contamination by the various processing stages involved in IC fabrication has been undertaken. This paper outlines the results obtained from processes involved in activation of ion implantation through annealing with a dielectric encapsulant, wet chemical etching, and metallization. Methods for removing or minimizing the effects of processing damage or contamination are also investigated. 相似文献
952.
Adaptive smoothing: a general tool for early vision 总被引:18,自引:0,他引:18
Saint-Marc P. Chen J.-S. Medioni G. 《IEEE transactions on pattern analysis and machine intelligence》1991,13(6):514-529
A method to smooth a signal while preserving discontinuities is presented. This is achieved by repeatedly convolving the signal with a very small averaging mask weighted by a measure of the signal continuity at each point. Edge detection can be performed after a few iterations, and features extracted from the smoothed signal are correctly localized (hence, no tracking is needed). This last property allows the derivation of a scale-space representation of a signal using the adaptive smoothing parameter k as the scale dimension. The relation of this process to anisotropic diffusion is shown. A scheme to preserve higher-order discontinuities and results on range images is proposed. Different implementations of adaptive smoothing are presented, first on a serial machine, for which a multigrid algorithm is proposed to speed up the smoothing effect, then on a single instruction multiple data (SIMD) parallel machine such as the Connection Machine. Various applications of adaptive smoothing such as edge detection, range image feature extraction, corner detection, and stereo matching are discussed 相似文献
953.
Protsko L.B. Sorenson P.G. Tremblay J.P. Schaefer D.A. 《IEEE transactions on pattern analysis and machine intelligence》1991,17(1):10-21
The authors formulate the criteria for drawing dataflow diagrams and describe the placement and routing algorithms used in a system called MONDRIAN. A generalized approach to the question of software diagrams is proposed based on the authors' experience with MONDRIAN and a metasystem approach to the creation of CASE (computer-aided software engineering) environments. A formal approach to the definition of software objects and their graphical representation is given. The use of location constraints as a basis for generalized layout algorithms is discussed 相似文献
954.
955.
S. O. Slesarevskii A. M. Belavskii M. N. Korotenko V. S. Lyubarskii V. P. Pavlenko V. A. Snigerev A. V. Tkachenko 《Atomic Energy》1989,67(5):853-855
Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 358–359, November, 1989. 相似文献
956.
957.
A new learning model for real-time, grey-level image segmentation is presented. The model gives excellent results for images with different shapes. 相似文献
958.
WC-(Fe, Ni, C) cemented carbides can be successfully transformation-toughened by careful control of binder composition and
taking into consideration the effect of thermal residual stress on the transformation characteristics of the binder. An additional
degree of control on the metastability of the binder phase can be achievedvia thermomechanical treatments. These treatments consist of transforming an austenitic binder to martensite by cooling in liquid
nitrogen followed by a suitable high temperature heat treatment to reaustenitize it. Thein situ deformation of the binder caused by the large shape and volume changes that accompany its transformation to martensite thus
provides the mechanical component of the thermomechanical treatment. Subsequent heat treatments not only reaustenitize the
binder but also modify its susceptibility to undergo stress-induced transformation. It is shown that the hardness/fracture
toughness behavior of WC-(Fe, Ni, C) cemented carbides can be significantly improved by the application of such treatments.
A qualitative explanation for the enhancements in fracture toughness provided by thermomechanical treatments is offered based
on a careful examination of the changes in phase constitution of the binder that occur during these treatments.
Formerly Manager, Research-Development, Reed Tool Company, Houston, TX. 相似文献
959.
V. V. Tcherdyntsev S. D. Kaloshkin A. I. Salimon E. A. Leonova I. A. Tomilin J. Eckert F. Schurack V. D. Rogozin S. P. Pisarev Yu. P. Trykov 《Materials and Manufacturing Processes》2002,17(6):825-841
Al-Cu-Fe alloys were prepared from elemental powders in a high-energy planetary ball mill. A sequence of solid state reactions resulting in quasicrystal (QC) phase formation takes place during heating of the as-milled powder. These reactions were studied by both differential scanning calorimetry and x-ray diffraction methods. Mechanically alloyed powders were consolidated by cold and hot pressing, as well as by explosive compaction. After annealing at sufficiently high temperatures, the consolidated samples are single-phase QC, except the ones consolidated by explosion. The high reactivity of the as-milled alloys causes the appearance of high porosity of the consolidated samples after the annealing. 相似文献
960.
The basic principles of a new surface acoustic wave (SAW) gas sensor are described. Being essentially a sensor of the sorption type, the proposed device possesses certain features of the thermometric SAW sensors and is not only sensitive to the vapors of volatile substances, but capable of detecting gases by their thermal properties as well. In contrast to the known thermometric SAW sensors, the proposed sensor is characterized by high temperature stability and fast response. A variant of the sensor based on a LiNbO3 SAW delay line is described and some results of the test for detecting propane-butane mixtures are presented. 相似文献