Collective Electrons

Figure 11-5. Internal pholoemission response as a function of photon energy for (a) an AI/MEH-PPV/ Ca structure biased to collect elections and (b) for the same AtfMEII-PPV/Ca structure and a Cut MEH-PPV/Ca structure biased to collect holes. Inset in (a) shows the electric field dependence of the photorcspon.se ihicshold for the AI/MEH-PPV/Ca structure biased to collect electrons.

Bi decays by emission of n, = 1.16meV with no y-transition. Thus, the only influences are those of mechanical recoil from the fj emission (maximum recoil energy 3.5 eV) and the ionization due to collective electron excitation (shakeoff). [Pg.84]

This method of data collection uses Portable Document Format (PDF) Forms. This approach is flexible and inexpensive. A number of commercial software packages such as Adobe Acrobat, LaText, and Microsoft Word and free software such as Python and R are used to create the PDF forms. Paper copies of the PDF forms may be used as an intermediate data collection. Electronic versions are completed at each site with Adobe Reader software. Completed forms are submitted on a CD or faxed as Extended Markup Language (XML)... [Pg.610]

Abdellatif et al. reported a method for data retention [56] in which collected electronic data forms of each participating site are saved on a read-only CD as PDF files after the site s database has been locked. SAS Output Delivery System (ODS), PROC Template, and PROC Forms were used to construct a read-only CD of the data forms in a PDF format for each site and then sent to the site s PI. [Pg.627]

Part 1 of the nitrogenase protein contains another interconnected group of Fe-S atoms, this one with eight iron atoms and seven sulfur atoms. This [8Fe-7S] group collects electrons and transmits them to the binding center. Part 2 of nitrogenase contains a third Fe-S group, this one made up of four iron atoms and four sulfur atoms. This part of the enzyme also binds two molecules of ATP. [Pg.1017]

Finally, theory involving collective electrons and the like, characteristic of ICC 1, appears less fi-equently in the catalytic hterature and theories involving local sites appear more often. The existence of coordination complex analogs may have played some part in this development. More recent theoretical developments relate primarily to chemisorbed spedes. [Pg.68]

The signal 1(E) detected at some energy loss E by a spectrometer collecting electrons scattered through angles up to j3 is given by ... [Pg.187]

Figure 5.39. Illustrating the focussing and dispersive properties of a magnetic prism in an electron energy-loss spectrometer. In a serial spectrometer a slit at D is used to ensure that only electrons of a single energy loss enter the detector. In a parallel spectrometer, a position-sensitive detector is placed at D to collect electrons of all energies in parallel.

One way to solve such stmctures is to collect electron dififraction patterns from difierent zone axes of the crystal to get an essentially complete 3D electron diffraction data set. Direct methods or the Patterson method can then be applied to phase the data, similar to what is done in X-ray diffraction (Gjonnes et al., 1998 Gemmi et al., 2000 Wagner et al., 1999). [Pg.302]

The parameter that directly measures how efficiently incident photons are converted to electrons is the IPCE. The wavelength-dependent IPCE term can be expressed as a product of the quantum yield for charge injection ( ), the efficiency of collecting electrons in the external circuit (17), and the fraction of radiant power absorbed by the material or light harvesting efficiency (LHE), as represented by Equation 17.8 ... [Pg.532]

Oxidative phosphorylation begins with the entiy of electrons into the respiratory chain. Most of these electrons arise from the action of dehydrogenases that collect electrons from catabolic pathways and funnel them into universal electron acceptors—nicotinamide nucleotides (NAD+ or NADP+) or flavin nucleotides (FMN or FAD). [Pg.692]

Nature of Active Sites. There is no apparent correlation between the increase of catalytic activity and a modification of the electronic structure of nickel oxide, since the electrical properties of both catalysts are identical. It is probable that local modifications of the nickel oxide surface are responsible for the change of its activity and of the reaction mechanism. It should be possible to associate these structural modification with local modifications of the height of the Fermi level, but it would be difficult to explain the results by the electronic theory of catalysis which considers only collective electrons or holes. A discussion based only on the influence of surface defects seems, therefore, to be more straightforward. [Pg.310]

ANODE. In the most general sense, an anode is tile electrode via which current enters a device. T he anode is the positively charged electrode of an elechulylrc cell See Electrochemistry. The anode (also frequently called the plate) is the principal electrode for collecting electrons in an electron tube, and is, therefore, operated at a positive potential with respect to the cathode. [Pg.104]

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