Transform-based

J. L. C. Sanz, E. B. Hinkle, and A. K. Jain, Raidon and Projection Transform-Based Computer Vision, Springer-Vedag, Berlin, 1988. 

Since the transformer will be in the circuit for only 15 to 20 seconds, the approximate short-time rating of the transformer can be considered to be 10-15% of its continuous rating. The manufacturer of the auto transformer would be a better judge to suggest the most appropriate rating of the transformer, based on the tapping and starting period of the motor. 

Structural subgoals may be useful in the application of transform-based strategies. This is especially so with structurally complex retrons which can be mapped onto a target in only one or two ways. It is often possible in such cases quickly to derive the structure of a possible intermediate in a trial retrosynthetic sequence. For instance, with 109 as TGT the quinone-Diels-Alder transform is an obvious T-goal. The retron for that transform can readily be mapped... 

Transform-based Strategy. A strategic guide for retrosynthetic analysis in which the application of a particular powerfully simplifying transform becomes a goal. 

Monoalkylthallium(III) compounds can be prepared easily and rapidly by treatment of olefins with thallium(III) salts, i.e., oxythallation (66). In marked contrast to the analogous oxymercuration reaction (66), however, where treatment of olefins with mercury(II) salts results in formation of stable organomercurials, the monoalkylthallium(III) derivatives obtained from oxythallation are in the vast majority of cases spontaneously unstable, and cannot be isolated under the reaction conditions employed. Oxythallation adducts have been isolated on a number of occasions (61, 71,104,128), but the predominant reaction pathway which has been observed in oxythallation reactions is initial formation of an alkylthallium(III) derivative and subsequent rapid decomposition of this intermediate to give products derived by oxidation of the organic substrate and simultaneous reduction of the thallium from thallium(III) to thallium(I). The ease and rapidity with which these reactions occur have stimulated interest not only in the preparation and properties of monoalkylthallium(III) derivatives, but in the mechanism and stereochemistry of oxythallation, and in the development of specific synthetic organic transformations based on oxidation of unsaturated systems by thallium(III) salts. 

Catalytic transformation based on combined enzyme and metal catalysis is described as a new class of methodology for the synthesis of enantiopure compounds. This approach is particularly useful for dynamic kinetic resolution in which enzymatic resolution is coupled with metal-catalyzed racemization for the conversion of a racemic substrate to a single enantiomeric product. 

A collection of notes by Sir Isaac Newton, thought by experts to be lost forever, have recently been rediscovered during cataloguing at the Royal Society and go on display to the public for the first time next week at the Royal Society s Summer Science Exhibition. The notes are written about alchemy, which some scientists in Newton s time believed to hold the secret for transforming base metals, such as lead, into the more precious metals... 

An orifice flow configuration is more suitable for applications requiring intense cavitational conditions, whereas for milder processes (requiring collapse pressure pulses typically between 15 and 20 bar) and for transformations based on physical effects, a venturi configuration is more suitable and energy efficient. 

Some single examples of this type of reaction were discussed in earlier sections, but due to the importance of these transformations, an additional overview will be provided here. One of the first transformations based on this strategy was published by Inoue and coworkers [134] using propargylic alkoxide, an arylhalide or vinyl bromide and C02 to give cyclic carbonates. The Balme group used this ap-... 

In this section, we present a pseudocode for an FEP alchemical transformation based on the dual-topology paradigm. The steps followed in this algorithm, specifically (c)-(f), may be implemented independently of the core of the program that generates an ensemble of configurations at a given A state - either Monte Carlo or molecular dynamics. This is probably the simplest scheme, which may be improved in several ways, as will be discussed in Sect. 2.9. 

Synthetic work commenced with evaluation of an azomethine ylide dipole for the proposed intramolecular dipolar cycloaddition. A number of methods exist for the preparation of azomethine ylides, including, inter alia, transformations based on fluoride-mediated desilylation of a-silyliminium species, electrocyclic ring opening of aziridines, and tautomerization of a-amino acid ester imines [37]. In particular, the fluoride-mediated desilylation of a-silyliminium species, first reported by Vedejs in 1979 [38], is among the most widely used methods for the generation of non-stabilized azomethine ylides (Scheme 1.6). 

Substitution of cyclopropane rings with the alkenyl group permits unique ring transformations based on metal coordination interaction with four -electrons. The transition-metal-induced ring-opening rearrangement also results in the formation of metallacycles. Further elaboration is attained by insertion and reductive elimination. 

In other words, the transformer-based Flyback behaves just like an inductor-based Buck-Boost, with the difference that the output voltage is V0R, not V0. So decreasing V0R calls for a decrease in D. However, the same input power still has to be drawn from the switch. So if the width of its waveform decreases, the height of the waveform must increase. Which means that the inductor current must also increase. So, decreasing V0R could also end up decreasing efficiency. That is why for most universal-input Flybacks, the best Vqr compromise is about 90V to 105V. 

The Heck reaction, a palladium-catalyzed vinylic substitution, is conducted with olefins and organohalides or pseudohalides are frequently used as reactants [15, 16], One of the strengths of the method is that it enables the direct monofunctionalization of a vinylic carbon, which is difficult to achieve by other means. Numerous elegant transformations based on Heck chemistry have been developed in natural and non-natural product synthesis. Intermolecular reactions with cyclic and acyclic al-kenes, and intramolecular cyclization procedures, have led to the assembly of a variety of complex and sterically congested molecules. 

Because of all these uncertainties and the questionable relationships found between bulk composition and activity, or even selectivities, we followed a different approach in order to gain an understanding and formulate a theory on surface composition responsible for FT and WGS reactivity. A logical sequence of catalyst surface transformations based on scientific principles was proposed and adapted to form a general model that can be used to explain our experimental observations. These proposed catalyst transformations will be discussed in a little more detail below. 

Many successful chemical transformations based on the rich and multifaceted chemistry of nitrones underlie various synthetic strategies. 

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