Spin LEDs

Open questions with respect to decay (e.g. conservation of energy and spin) led to Fermi s hypothesis of the existence of another elementary particle, the neutrino, in 1934. This particle should be neutral and have a mass of approximately zero. Due to these properties its detection was very difficult. The first successful experiment was... 

Semiconductor nanoparticles and QDs are widely used in various fields such as luminescent biolabels [150-152] and have been demonstrated as components in regenerative solar cells [153-155], optical gain devices [24] and electroluminescent devices [23, 156, 157]. DMS have applications in spin-based electronics technologies, or spintronics [158-161]. Spintronic devices such as magnetic-optic switches, magnetic sensors, spin valve transistors and spin LEDs can be activated by implanting ferromagnetic Mn, Ni, Co and Cr in semiconductors [162-165]. Some of the applications of semiconductor nanoparticles or QDs have been explained in this section. 

For quadnipolar nuclei, the dependence of the pulse response on Vq/v has led to the development of quadnipolar nutation, which is a two-dimensional (2D) NMR experiment. The principle of 2D experiments is that a series of FIDs are acquired as a fimction of a second time parameter (e.g. here the pulse lengdi applied). A double Fourier transfomiation can then be carried out to give a 2D data set (FI, F2). For quadnipolar nuclei while the pulse is on the experiment is effectively being carried out at low field with the spin states detemiined by the quadnipolar interaction. In the limits Vq v the pulse response lies at v and... 

New Developments in Spinning and Drawing. The continual effort by the fiber producers to increase production, lower manufacturing costs, and improve quaUty has led to a better understanding of the effects of the spinning and drawing process on physical and molecular stmcture of... 

Experimental information for polymeric LED is sparse. A key problem for conventional lime-of-flighl studies is that the condition of generating a sheet of carriers whose spatial extension is small compared to the thickness of a = 100 nm film is difficult to meet. On the other hand, thick films fabricated, for instance, by solvent casting rather than by spin coating, may differ regarding their morphology and, concomitantly, the built-in-disorder. On the fundamental side, transport in... 

With the radical 29, even though loss of an equatorial hydrogen should be sterically less hindered and is favored thermodynamically (by relief of 1,3 interactions of the axial methyl), there is an 8-fold preference for loss of the axial hydrogen (at 100 ( i. The selectivity observed in the disproportionation of this and other substituted cyclohexyl radicals led Beckwith18 to propose that disproportionation is subject to stereoelectronic control which results in preferential breaking of the C-H bond which has best overlap with the orbital bearing the unpaired spin. 

Dirac was led to this equation for a spin particle by demanding that ... 

Certain numbers of neutrons and protons were recognized by Elsasser (75) as conferring increased stability on nuclei. These numbers are 2, 8, 20, 50, 82, and 126. (The set is sometimes considered to include 28 also.) It was in part their effort to account for these numbers that led Mayer and Haxel, Jensen, and Suess to propose their shell model with spin-orbit coupling. 

PPy was the first conducting polymer to be structurally analyzed. The discovery that a,a -disubstituted pyrroles did not electropolymerize led to the conclusion that the pyrrole units in PPy are a-linked Magic angle spinning C-NMR... 

A second unusual EPR spectrum was observed in the oxidized (as-isolated) protein (Fig. 3). This spectrum, which was assigned to an S = z system, was not reminiscent of any Fe-S cluster. Indeed, with g-values of 1.968, 1.953, and 1.903, it looked more like a molybdenum or tungsten spectrum. However, chemical analysis ruled out the possibility that this EPR spectrum arose from Mo or W, and the spectrum was assigned to an Fe-S center instead. The spin concentration, however, was sub stoichiometric and sample-dependent. Furthermore, when the as-isolated protein was oxidized with ferricyanide, it became EPR silent. This, together with the iron determination and the fingerprint of the reduced protein, led Hagen and colleagues to the... 

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