Chemical reaction initiator

Margulis MA, Mal tsev (1968) Estimation of energetic yield of chemical reactions initiated by ultrasonic waves. II. Initial chemical acoustic yields of products of water decomposition by ultrasound. Zh Fiz Khim 42 2660-2663, Russ J Phys Chem (42) 1447-1451... 

Srivastava SC (1958) Chemical reactions initiated by ultrasonic waves. Nature 182 47... 

Most first-aid kits contain instant cold compresses to treat injuries and burns. A simple chemical reaction, initiated by the user, provides for the immediate application of a cooling remedy. 

Elegant work by Van der Hoff [60] seems to suggest that it is the latter, or more correctly there is a Gaussian distribution about the midpoint of a chain. However, as to whether the main chains are primarily broken by ultrasonic action is still open to question since it is possible that the main chain scissions are secondary effects due to chemical reactions initiated by unstable intermediates, such as free radicals or ions, produced by sonication. For example McKay [61] has shown that hydroxyl radicals, generated by the oxidation of Fe by H2O2, are the cause of chain scission in polyacrylamide molecules in aqueous solution. 

Photodegradable Able to decompose through a chemical reaction initiated by direct exposure to the sun s ultraviolet light. 

The monomer is consumed by two chemical reactions initiation, in which new polymer molecules are generated, and propagation, in which existing polymer molecules me extended to higher molecular weight. In steady state VDP, both reactions proceed continuously inside polymeric coating, in the reaction zone just behind the growth interface. 

Another approach is to employ a metal minigrid or a thin metal or semiconductor film for the working electrode (Chap. 11). These electrodes permit transmittance of the optical beam through the electrode and are readily adapted for use in thin-layer cells. Fast heterogeneous or homogeneous electron transfer reactions, or homogeneous chemical reactions initiated by the electrode... 

The global field of photochemistry has been defined in Coxon Halton as the study of chemical reactions initiated by light. 13 Although succinct, it may be too restrictive for the purposes of vision. The field might be better described by replacing the expression chemical reactions by chemical processes or chemical interactions. The revised definition would allow mechanisms, such as sensitization of one species by another without any change in species to occur. This... 

Potential-pH diagram — Graphical display of electrode potentials (usually on the SHE-scale) vs. -+pH values for a selected element based on thermodynamic calculations. In the plot the chemically stable species are indicated taking into account all conceivable electrochemical as well as chemical reactions. Initially proposed and extensively researched by Pourbaix. 

Finally, we introduce the First Law of Thermodynamics as follows Let e0 and e be the energies of the material per unit mass of material being overtaken in unit time by unit area of the shock front (for which mt - 1) the difference e - e0 in energy, before and after the shock wave has hit, must reflect any chemical reactions initiated by the shock. The change in kinetic energy acquired by this material is u2/2 thus, we write... 

Photochemical reaction Any chemical reaction initiated as a result of absorption of light... 

Chemical reaction Initiated by mechanical actions are a subject of interest in the field of mechanochemistry (5). Moreover, mechanical methods, such as grinding. 

The polymerisation of adhesives follows the basic rule of chemical reactions -initiation, propagation and termination steps - and because they are reactive they should truly cure. The following is a brief summary of typical adhesives used by consumers or for industrial applications. 

Postexposure bake of the wafer. A postexposure bake (PEB) improves contrast of the photoresist before its development. The PEB process causes three effects 1) diffusion of the PAC 2) solvent evaporation and 3) thermally induced chemical reactions. In general, the dissolution rate of a resist decreases as a function of a PEB temperature. PEB becomes more important for the photoresists with a chemical amplification (CA) feature. The photoresists need the PEB to complete chemical reactions initiated by exposure. 

A detonation refers to a shock wave in an energetic material that runs at a steady velocity driven by chemical reactions initiated at the shock front [38,39]. Due to damping at edges and surfaces, the detonation state can occur only if the sample is larger than the critical failure diameter [3]. With a few exceptions, the critical diameter is typically in the nun to cm range, so detonations are associated with macroscopic loads of energetic materials and are extremely powerful. For HMX, the detonation velocity is 9.1 km/s, the pressure is 39 GPa,... 

Chemical reactions initiated in gas discharges and plasmas, in particular in low-temperature, nonequilibrium plasmas, have become indispensable for the advancement of many key technologies in the past 10-15 years (see, e.g Becker et al., 1992 Garscadden, 1992). The plasma-assisted etching of microstructures and the deposition of high-quality thin films with well-defined properties have become crucial steps in the fabrication of microelectronic devices with typical feature sizes of less than 0.5 /rm. The manufacture of state-of-the-art microchips now involves hundreds of process steps, most of them serial, to yield circuits with millions of discrete elements and interconnections in an area of a single square centimeter (Garscadden, 1992). Each step is a physical-chemical interaction that must be controlled. More than one-third of the process steps rely on plasma... 

Atmospheric Chemistry of Hydrocarhons. Hydrocarbon compounds that are released into the troposphere are oxidized by a series of chemical reactions initiated by one or more of a variety of free radicals, such as OH, O3, and NO3. The principal reaction pathways are illustrated in Figure 1. An excellent review of the chemistry summarized in this figure has been... 

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