17,234 research outputs found
Analytical comparisons of ablative nozzle materials final report, jun. 20, 1963 - nov. 20, 1964
Reaction kinetics ablation program to predict ablation performance of rocket nozzle heat protection material
Quantum transport through single-molecule junctions with orbital degeneracies
We consider electronic transport through a single-molecule junction where the
molecule has a degenerate spectrum. Unlike previous transport models, and
theories a rate-equations description is no longer possible, and the quantum
coherences between degenerate states have to be taken into account. We present
the derivation and application of a master equation that describes the system
in the weak-coupling limit and give an in-depth discussion of the parameter
regimes and the new phenomena due to coherent on-site dynamics
An introduction to spacecraft thermal control
External and internal passive and active methods for spacecraft thermal control - material insulation and structural propertie
Spin injection from perpendicular magnetized ferromagnetic -MnGa into (Al,Ga)As heterostructures
Electrical spin injection from ferromagnetic -MnGa into an (Al,Ga)As
p-i-n light emitting diode (LED) is demonstrated. The -MnGa layers show
strong perpendicular magnetocrystalline anisotropy, enabling detection of spin
injection at remanence without an applied magnetic field. The bias and
temperature dependence of the spin injection are found to be qualitatively
similar to Fe-based spin LED devices. A Hanle effect is observed and
demonstrates complete depolarization of spins in the semiconductor in a
transverse magnetic field.Comment: 4 pages, 3 figure
Density matrix reconstruction from displaced photon number distributions
We consider state reconstruction from the measurement statistics of phase
space observables generated by photon number states. The results are obtained
by inverting certain infinite matrices. In particular, we obtain reconstruction
formulas, each of which involves only a single phase space observable.Comment: 19 page
Determination of Effective Permittivity and Permeability of Metamaterials from Reflection and Transmission Coefficients
We analyze the reflection and transmission coefficients calculated from
transfer matrix simulations on finite lenghts of electromagnetic metamaterials,
to determine the effective permittivity and permeability. We perform this
analysis on structures composed of periodic arrangements of wires, split ring
resonators (SRRs) and both wires and SRRs. We find the recovered
frequency-dependent permittivity and permeability are entirely consistent with
analytic expressions predicted by effective medium arguments. Of particular
relevance are that a wire medium exhibits a frequency region in which the real
part of permittivity is negative, and SRRs produce a frequency region in which
the real part of permeability is negative. In the combination structure, at
frequencies where both the recovered real part of permittivity and permeability
are simultaneously negative, the real part of the index-of-refraction is found
also to be unambigously negative.Comment: *.pdf file, 5 figure
State education as high-yield investment: human capital theory in European policy discourse
Human Capital Theory has been an increasingly important phenomenon in economic thought over the last 50 years. The central role it affords to education has become even more marked in recent years as the concept of the âknowledge economyâ has become a global concern. In this paper, the prevalence of Human Capital Theory within European educational policy discourse is explored. The paper examines a selection of policy documents from a number of disparate European national contexts and considers the extent to which the ideas of Human Capital Theory can be seen to be influential. In the second part of the paper, the implications of Human Capital Theory for education are considered, with a particular focus on the possible ramifications at a time of economic austerity. The paper argues that Human Capital Theory risks offering a diminished view of the person, a diminished view of education, but that with its sole focus on economic goals leaves room for educationists and others to argue for the educational, social, and moral values it ignores, and for the conception of the good life and good society it fails to mention
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