The CNN Universal Machine and Supercomputer [10] is the first stored program analog computing array architecture. Its various implementations, in parts, show that for this new kind of analogic computing we need all the essential programming tools which digital computers have, though in different form. Namely, we need an analogic algorithm (e.g. in a form of a flow diagram), a high level language (e.g. the "Analogic CNN Language (ACL)"), a compiler, an operating system, and a generated machine code. Although they are quite simple in our present phase of making these machines, their existence suggest a similar development to the one we had in the 1970's for microprocessors. The main difference is accounted for by the presence of analog array dynamics as the key instruction/operation in the analogic CNN algorithms [1-8]. In what follows, we outline the main ideas and a simple implementation. Inclusively, we suggest a framework for the implementation of a development system for CNN universal chips
Abstract The asymmetric fluorination of substituted cyclohexanones generates quaternary fluorine‐containing stereocenters through the combination of two separate catalytic cycles: enamine activation of the ketone and chiral anion phase‐transfer activation of the fluorination agent.
This book is mainly based on the first and second symposia on Nanotechnology in Catalysis held in 2001 and 2002, but it also includes several contributions not presented in the symposia to round out the scope of the subject. The contents are the most up to date developments made by researchers all over the world in the catalysis field in this fascinating nanotechnology era. It reflects some of the frontier areas of nanoscience and nanotechnology in fabricating and characterizing catalysts and carrying out studies to prove their superior selectivity and activity. The field of application of nanotechnology for the development of catalysts for green chemistry is likely to grow rapidly during the next decade. This book hopes to contribute to the evolution of nanotechnology in that direction.
A concise derivation of Kirchhoff’s theory for naturally curved and twisted rods is presented as a prelude to the derivation of the theory for the elastic response of rods that have undergone prior plastic deformation.
A new molecular precursor strategy has been used to prepare a series of single-site catalysts that possess isolated iron centers supported on mesoporous SBA-15 silica. The iron centers were introduced via grafting reactions of the tris(tert-butoxy)siloxy iron(III) complex Fe[OSi(O(t)Bu)(3)](3)(THF) with SBA-15 in dry hexane. This complex reacts cleanly with the hydroxyl groups of SBA-15 to eliminate HOSi(O(t)Bu)(3) (as monitored by (1)H NMR spectroscopy) with formation of isolated surface species of the type identical with SiO-Fe-[OSi(O(t)Bu)(3)](2)(THF). In this way, up to 21% of the hydroxyl sites on SBA-15 were derivatized (0.23 Fe nm(-)(2)), and iron loadings in the range of 0.0-1.90% were achieved. The structure of the surface-bound iron species, as determined by spectroscopic methods (electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), UV-vis, and in situ infrared measurements) and by elemental analyses, contains a pseudotetrahedral iron(III) center. The THF ligand of this surface-bound complex was quantitatively displaced by acetonitrile (by (1)H NMR spectroscopy). Calcination of these materials at 300 degrees C for 2 h under oxygen resulted in removal of all organic matter and site-isolated iron surface species that are stable to condensation to iron oxide clusters. Spectroscopic data (UV-vis and EPR) suggest that the iron centers retain a mononuclear, pseudotetrahedral iron(III) structure after calcination. The calcinated, iron-grafted SBA-15 materials exhibit high selectivities as catalysts for oxidations of alkanes, alkenes, and arenes, with hydrogen peroxide as the oxidant.
We have discovered that a class of inorganic sulfides [Li2S, (NH4)2S, Na2S⋅9H2O, etc.] imparts excellent electronic properties to GaAs surfaces. The surface recombination velocity at the interface between Na2S⋅9H2O and GaAs begins to approach that of the nearly ideal AlGaAs/GaAs interface. We propose the formation of a robust covalently bonded sulfide layer to explain the favorable electronic quality of such interfaces.
