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Mantooth B.A. Weiss P.S. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2003,91(11):1785-1802
One of the ultimate miniaturizations in nanotechnology is molecular electronics, where devices will consist of individual molecules. There are many complications associated with the use of molecules in electronic devices, such as the electronic perturbations in the molecule associated with being bonded to an electrode, how electrons traverse the metal-molecule junction, and the difficulty of macroscopically addressing single to very few molecules. Whether fabricating a test structure or a usable device, the use of self-assembly is fundamental to the fabrication of molecular electronic devices. We will discuss how to fabricate self-assembled monolayers into test assemblies and how to use intermolecular interactions to direct molecules into desired positions to create nanostructures and to connect functional molecules to the outside world. These assemblies serve as test structures for measurements on single or bundled molecules. The development of several experimental techniques, including various scanning probes, mercury drop junctions, break junctions, nanopores, crossed wires, and other techniques using nanoparticles have enabled the ability to test these structures and make reproducible measurements on single molecules. Many of these methods have been developed to test molecules with potential for integration into devices such as oligo (phenylene-ethynylene) molecules and other /spl pi/-conjugated molecules, in ensemble or single-molecule measurements. 相似文献
3.
MJ Weiss 《Canadian Metallurgical Quarterly》1997,11(6):1185-1198
Two advances in murine embryonic stem (ES) cell technology and their applications for the study of hematopoietic stem cells (HSCs) are discussed in this article. First, ES cells induced to differentiate in vitro form hematopoietic lineages in a fashion that recapitulates the ontogeny of blood formation in the embryo. This system offers a unique opportunity to isolate, examine, and manipulate the most primitive hematopoietic progenitors. Second, targeted gene ablation (knockout) studies in ES cells have identified several genes that are required for normal hematopoiesis and may function in the formation, maintenance, and differentiation of HSCs. Insights into murine hematopoiesis gained through the study of ES cells generally should be applicable to other vertebrates, including humans. 相似文献
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A system for person-independent classification of hand postures against complex backgrounds in video images is presented. The system employs elastic graph matching, which has already been successfully applied for object and face recognition. We use the bunch graph technique to model variance in hand posture appearance between different subjects and variance in backgrounds. Our system does not need a separate segmentation stage but closely integrates finding the object boundaries with posture classification. 相似文献
6.
I. Kasatkin F. Girgsdies T. Ressler R. A. Caruso J. H. Schattka J. Urban K. Weiss 《Journal of Materials Science》2004,39(6):2151-2157
The orientation relations m(100) || t(001), m[001] || t[110]; m(011) || t(100), m[100] || t[001]; m(100) || t(110), m[001] || t[001]; m(013) || t(116), m[001] || t[001] (indices for the primitive tetragonal cell) have been found between the tetragonal (t) and monoclinic (m) domains during the electron irradiation-induced m-t phase transition observed in-situ with HREM within isolated zirconia nanoparticles. Geometric models of the m-t interfaces are proposed. 相似文献
7.
George Weiss 《Mathematics of Control, Signals, and Systems (MCSS)》1991,4(2):193-203
We give an elementary proof of the well-known fact that shift-invariant operators onL
2[0, ∞) are represented by transfer functions which are bounded and analytic on the right open half-plane. We prove a generalization
to Banach space-valuedL
p
-functions, where 1≤p<∞. We show that the result no longer holds forp=∞.
This research was supported partially by the Weizmann Fellowship, and partially by the Air Force Office of Scientific Research
under Contract F49620-86-C-0111. 相似文献
8.
Matthias Zobel Joachim Denzler Benno Heigl Elmar Nöth Dietrich Paulus Jochen Schmidt Georg Stemmer 《Machine Vision and Applications》2003,14(1):26-34
Abstract. This contribution introduces MOBSY, a fully integrated, autonomous mobile service robot system. It acts as an automatic dialogue-based
receptionist for visitors to our institute. MOBSY incorporates many techniques from different research areas into one working
stand-alone system. The techniques involved range from computer vision over speech understanding to classical robotics.
Along with the two main aspects of vision and speech, we also focus on the integration aspect, both on the methodological
and on the technical level. We describe the task and the techniques involved. Finally, we discuss the experiences that we
gained with MOBSY during a live performance at our institute. 相似文献
9.
As in other structurally disordered solids, the low temperature acoustic properties of poly-crystalline aluminium are governed by atomic two-level tunneling systems. The particular temperature variation of sound velocity and internal friction depends on the dynamical behaviour of these tunneling systems, which is expected to be determined by interaction with thermal phonons and conduction electrons as in metallic glasses. In earlier measurements on aluminium-wires no significant difference was found whether the sample was superconducting or kept in the normal state by a sufficiently high magnetic field and the concluding claim was ‘absence of electron-assisted relaxation for tunneling systems in poly-crystalline metals’. In this report, vibrating reed measurements are presented of pure poly-crystalline Al with a special sample shape that reduces the influence of the clamping. We in fact find significant differences between the sample being normal conducting or superconducting. The overall behaviour indeed resembles very closely that of metallic glasses and clearly demonstrates that also in Al tunneling systems couple to conduction electrons as expected. As a quantitative result we may state that the density of states of tunneling systems in poly-crystalline Al is considerably smaller than in metallic glasses. PACS numbers: 61.43.-j, 62.65.+k, 63.50.+x 相似文献
10.
It is well recognized that performance changes over time. However, the effect of these changes on overall assessments of performance is largely unknown. In a laboratory experiment, we examined the influence of salient Gestalt characteristics of a dynamic performance profile on supervisory ratings. We manipulated performance trend (flat, linear-improving, linear-deteriorating, U-shaped, and ∩-shaped), performance variation (small, large), and performance mean (negative, zero, positive) within subjects and display format (graphic, tabular) between subjects. Participants received and evaluated information about the weekly performance of different employees over a simulated 26-week period. Results showed strong main effects on performance ratings of both performance mean and performance trend, as well as interactions with display format. Theoretical and practical implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献