4,211 research outputs found
Counter Patent
Circuit for measuring wide range of pulse rates by utilizing high capacity counte
Circuit counts pulses and indicates time of occurrence of slow pulses
Counter includes one section which counts the first several pulses, and a second section which counts pulses from a clock between the beginning of a sampling interval and the receipt of the first pulse by the circuit. The number of clock pulses indicates receipt time of the first pulse
Transport through anisotropic magnetic molecules with partially ferromagnetic leads: Spin-charge conversion and negative differential conductance
We theoretically investigate inelastic transport through anisotropic magnetic
molecules weakly coupled to one ferromagnetic and one nonmagnetic lead. We find
that the current is suppressed over wide voltage ranges due to spin blockade.
In this system, spin blockade is associated with successive spin flips of the
molecular spins and depends on the anisotropy energy barrier. This leads to the
appearance of a window of bias voltages between the Coulomb blockade and spin
blockade regimes where the current is large and to negative differential
conductance at low temperatures. Remarkably, negative differential conductance
is also present close to room temperature. Spin-blockade behavior is
accompanied by super-Poissonian shot noise, like in nonmagnetic quantum dots.
Finally, we show that the charge transmitted through the molecule between
initial preparation in a certain spin state and infinite time very strongly
depends on the initial spin state in certain parameter ranges. Thus the
molecule can act as a spin-charge converter, an effect potentially useful as a
read-out mechanism for molecular spintronics.Comment: 8 pages with 5 figures, version as publishe
Spin amplification, reading, and writing in transport through anisotropic magnetic molecules
Inelastic transport through a single magnetic molecule weakly coupled to
metallic leads is studied theoretically. We consider dynamical processes that
are relevant for writing, storing, and reading spin information in molecular
memory devices. Magnetic anisotropy is found to be crucial for slow spin
relaxation. In the presence of anisotropy we find giant spin amplification: The
spin accumulated in the leads if a bias voltage is applied to a molecule
prepared in a spin-polarized state can be made exponentially large in a
characteristic energy divided by temperature. For one ferromagnetic and one
paramagnetic lead the molecular spin can be reversed by applying a bias voltage
even in the absence of a magnetic field. We propose schemes for reading and
writing spin information based on our findings.Comment: 5+ pages with 5 figure
Individual Differences in the Experience of Cognitive Workload
This study investigated the roles of four psychosocial variables – anxiety, conscientiousness, emotional intelligence, and Protestant work ethic – on subjective ratings of cognitive workload as measured by the Task Load Index (TLX) and the further connections between the four variables and TLX ratings of task performance. The four variables represented aspects of an underlying construct of elasticity versus rigidity in response to workload. Participants were 141 undergraduates who performed a vigilance task under different speeded conditions while working on a jigsaw puzzle for 90 minutes. Regression analysis showed that anxiety and emotional intelligence were the two variables most proximally related to TLX ratings. TLX ratings contributed to the prediction of performance on the puzzle, but not the vigilance task. Severity error bias was evident in some of the ratings. Although working in pairs improved performance, it also resulted in higher ratings of temporal demand and perceived performance pressure
A new HWWA raw material price index
In this place we regularly published the HWWA Index of World Market Prices which has been computed since the fifties and was a comprehensive indicator of the price movements of the major raw materials traded in the world markets. Unavoidably, an, index of this kind has to be adjusted from time to time to allow for changes in the pattern of world trade. Such an adjustment has just been completed. For a better understanding and use of the new index by our readers in the future the following explanation should serve
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