445,360 research outputs found
Activation Energy of Metastable Amorphous Ge2Sb2Te5 from Room Temperature to Melt
Resistivity of metastable amorphous Ge2Sb2Te5 (GST) measured at device level
show an exponential decline with temperature matching with the steady-state
thin-film resistivity measured at 858 K (melting temperature). This suggests
that the free carrier activation mechanisms form a continuum in a large
temperature scale (300 K - 858 K) and the metastable amorphous phase can be
treated as a super-cooled liquid. The effective activation energy calculated
using the resistivity versus temperature data follow a parabolic behavior, with
a room temperature value of 333 meV, peaking to ~377 meV at ~465 K and reaching
zero at ~930 K, using a reference activation energy of 111 meV (3kBT/2) at
melt. Amorphous GST is expected to behave as a p-type semiconductor at Tmelt ~
858 K and transitions from the semiconducting-liquid phase to the
metallic-liquid phase at ~ 930 K at equilibrium. The simultaneous Seebeck (S)
and resistivity versus temperature measurements of amorphous-fcc mixed-phase
GST thin-films show linear S-T trends that meet S = 0 at 0 K, consistent with
degenerate semiconductors, and the dS/dT and room temperature activation energy
show a linear correlation. The single-crystal fcc is calculated to have dS/dT =
0.153 {\mu}V/K for an activation energy of zero and a Fermi level 0.16 eV below
the valance band edge.Comment: 5 pages, 5 figure
Traveling mirror compressor delay line with nonconstant capacitance
The scaling relations for a traveling mirror magnetic compressor [P.M. Bellan, Phys. Rev. Lett. 43, 858 (1979)] having nonconstant capacitance are derived. Varying capacitance (rather than inductance) makes possible a lower impedance device, and hence, higher field levels or faster compression times
Working for Scrooge: Worst Companies of 2011 for Freedom of Association
This document is part of a digital collection provided by the Martin P. Catherwood Library, ILR School, Cornell University, pertaining to the effects of globalization on the workplace worldwide. Special emphasis is placed on labor rights, working conditions, labor market changes, and union organizing.ILRF_Working_For_Scrooge_2011.pdf: 858 downloads, before Oct. 1, 2020
Lounela, Anu, Berglund, Eeva and Kallinen Timo (eds) 2019. Dwelling in Political Landscapes. Contemporary Anthropological Perspectives
Lounela, Anu, Berglund, Eeva and Kallinen Timo (eds) 2019. Dwelling in Political Landscapes. Contemporary Anthropological Perspectives. Helsinki: SKS. Studia Fennica Anthropologica 4. 293 p. ISBN 978-951-858-087-7 (Print), ISBN 978-951-858-114-0 (PDF) ISBN 978-951-858-113-3 (EPUB). https://doi.org/10.21435/sfa.4
Historical land-use information from culturally modified trees
In a global perspective, the human impact on forest ecosystems varies greatly in type, frequency and magnitude. Knowledge of the history of forest use is crucial for understanding the development of forests, which in turn helps to understand how societies react to forest development. Culturally modified trees (CMTs), recorded in the western U.S., northern Scandinavia and south-eastern Australia, are features that can be dated precisely, and they bear witness to unique events of human activity. CMTs are traces from historical uses of forest resources that reflect the activities of local communities and extend far back in time, and therefore offer information not usually available from other sources. In this thesis I argue that CMTs have high potential for assessing human activity and possibly human impacts on forest ecosystems, particularly those concerning local indigenous uses. Periods of increased activity in a certain area are reflected in peaks in the distribution of CMT dates. These also show the time period and speed of abandonment of a traditional forest use in a landscape. The possibility to learn about the people, their behaviour and activities in the forest are good, but their impact on ecosystems will always be difficult to assess when only CMT data are available. Therefore, it is important to learn as much as possible about traditional customs expressed in CMTs, in combination with oral and ethnological sources, and the role of CMTs in the traditional use of the forest. In this way it is possible to estimate what the density and distribution of CMTs in the landscape actually tells us about historical impact on the ecosystem. CMTs contradict the idea of βpristineβ forests but symbolize the traditional view that people are part of nature rather than separate from it
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