Cascade capture

Some relatively new analyses in the theory of nonradiative transitions have followed from the fact that there is no basic reason why our three primary processes cannot also take place in combination. Thus Gibb et al. (1977) propose a process of cascade capture into an excited electronic state and subsequent multiphonon emission from there. The results of this model were applied to capture and emission properties of the 0.75-eV trap in GaP. A more detailed analysis has since been given by Rees et al. (1980). Similarly, cascade capture followed by an Auger process with a free carrier seems a quite likely process. However, we are not aware that such a model has as yet been suggested. The third possible combination of processes, namely Auger with multiphonon, has been examined by Rebsch (1979) and by Chernysh... 

Recombination at and excitation from deep levels are emphasized. Nonradiative transitions at defect levels—Auger, cascade capture, and multiphonon emission processes—are discussed in detail. Factors to be considered in the analysis of optical cross sections which can give information about the parity of the impurity wave function and thus about the symmetry of a particular center are reviewed. 

Fig. 1. Some representative y-cascades from the observed neutron capture y-spectrum of Mn. From Bartholomew et al. (3).

The process of j3-decay in some respects offers simpler radiochemical consequences than do neutron capture and other reactions, because (a) the nuclear recoil energy is very low and (b) the decay schemes, and thus the probability of Auger cascades, are generally well known. Despite this, no clear mechanisms have been worked out. 

What alternative routes are open for the dissipation of the energy of the capture y-cascade ... 

Assuming the contribution of the potential energy curves which have not been taken into account to be almost constant with the collision energy, such calculations could provide a relative estimate of the variation of the double capture cross-sections with the collision energy. The results presented in Fig. 7 seem to be coherent with this hypothesis and to corroborate a cascade effect for the double electron capture process. 

Grigg, R. Sridharan, V. (1999) Palladium Catalyzed Cascade Cyclisation - anion Capture, Relay Switches and Molecular Queues. Journal of Organometallic Chemistry, 576, 65-87. 

The microbes use two general strategies to synthesize ATP respiration and fermentation. A respiring microbe captures the energy released when electrons are transferred from a reduced species in the environment to an oxidized species (Fig. 18.1). The reduced species, the electron donor, sorbs to a complex of redox enzymes, or a series of such complexes, located in the cell membrane. The complex strips from the donor one or more electrons, which cascade through a series of enzymes and coenzymes that make up the electron transport chain to a terminal enzyme complex, also within the cell membrane. 

Electron capture, in which an inner-shell electron is captured by a proton in the nucleus with the formation of a neutron. X-rays are emitted as the electrons cascade down to fill the vacancy in the lower energy level. 

The items listed in the cascaded menu are the types of objects we can create using Capture as the front end. For this text, we are concerned only with the Project selection, which is used to draw schematics and simulate circuits, and the Library selection, which is used to create part libraries. Select Project to create a new project ... 

In connection with the cascade process it should also be mentioned that cascade, by itself, could explain carrier recombination (i.e., not merely capture,... 

Specifically, in the first step of the energy cascade, the light is captured by the DVB dimer located in the core of the complex. The energy is then transferred to peripherally located bilins (MBV, PCB 158) through a complex network of interactions that, owing to the very similar timescales and spectral features, are hard to separate. Probably, energy migration from DBV bilins to the MBV bilins occurs on a timescale (T) 0.6 ps) faster than the transfer... 

Captured within the last of these bullet points is the essence of drug therapy The goal is to administer a drug that will bind with a receptor and lead to a beneficial cascade of biological information flow that produces the desired therapeutic effect. 

Polyols of a cascade type as a water-solubilizing element of carborane derivatives for boron neutron capture therapy. [H. Nemoto, J. G. Wilson, H. Nakamura, Y. Yamamoto, J. Org. Chem. 1992, 57, 435-435] [ 811]. 

Exotic atoms are produced by stopping a beam of negatively charged particles like muons, pions, or antiprotons in a target, where they are captured in the Coulomb potential of the atoms at high principal quantum numbers n. These systems deexcite mainly by fast Auger emission of electrons in the upper part of the atomic cascade and more and more by X-radiation for lower-lying states. 

Fig. 1. Energy levels of the antiproton in pHe+. The p is captured by replacing one of the Is electrons, which corresponds for the p to a state with principal quantum number no JW /m, where M is the reduced mass of the atomcule, and m the electron mass. About 3% of antiprotons are captured in metastable states (black lines) at high angular momenta L n — 1, for which deexcitation by Auger transitions is much slower than radiative transitions. The lifetimes of these states is in the order of /is. The antiprotons follow predominantly cascades with constant vibration quantum number v = n — L — 1 (black arrows) until they reach an auger-dominated short-lived state. The atomcule then ionizes within < 10 ns and the pHe++ is immediately destroyed in the surrounding helium medium. The overall average lifetime of atomcules is about 3 — 4 ps...

The emphasis on presentation in many of the original tags (such as fonts, colors, and layout) muddled the separation of content from style. The World Wide Web Consortium soon developed technologies (CSS, or cascading style sheets, and XSL, or extensible stylesheet language more information on this and other XML issues is available at http //www.w3c. org/) to help overcome this problem, but as with HTML, CSS is variably implemented in most browsers. Most commercial tools for authoring HTML emphasize presentation or interactivity (to capture the reader s attention), and in such HTML, the content is subservient to the style. 

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