262 research outputs found
A thermoelectric power generating heat exchanger: Part I - Experimental realization
An experimental realization of a heat exchanger with commercial
thermoelectric generators (TEGs) is presented. The power producing capabilities
as a function of flow rate and temperature span are characterized for two
different commercial heat transfer fluids and for three different thermal
interface materials. The device is shown to produce 2 W per TEG or 0.22 W
cm at a fluid temperature difference of 175 C and a flow rate
per fluid channel of 5 L min. One experimentally realized design
produced 200 W in total from 100 TEGs. For the design considered here, the
power production is shown to depend more critically on the fluid temperature
span than on the fluid flow rate. Finally, the temperature span across the TEG
is shown to be 55% to 75% of the temperature span between the hot and cold
fluids.Comment: 9 pages, 11 figure
Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy
The spinel/perovskite heterointerface -AlO/SrTiO hosts a
two-dimensional electron system (2DES) with electron mobilities exceeding those
in its all-perovskite counterpart LaAlO/SrTiO by more than an order of
magnitude despite the abundance of oxygen vacancies which act as electron
donors as well as scattering sites. By means of resonant soft x-ray
photoemission spectroscopy and \textit{ab initio} calculations we reveal the
presence of a sharply localized type of oxygen vacancies at the very interface
due to the local breaking of the perovskite symmetry. We explain the
extraordinarily high mobilities by reduced scattering resulting from the
preferential formation of interfacial oxygen vacancies and spatial separation
of the resulting 2DES in deeper SrTiO layers. Our findings comply with
transport studies and pave the way towards defect engineering at interfaces of
oxides with different crystal structures.Comment: Accepted as Rapid Communications in Physical Review
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