11 resultados para THERMOELECTRIC FIGURE
em Deakin Research Online - Australia
Resumo:
A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) Å, b = 6.0521(11) Å, c = 9.568(2) Å, and β = 98.121(2)°. Cu5Sn2Te7 is a superstructure of sphalerite and exhibits tetrahedral coordination of Cu, Sn, and Te atoms, containing a unique adamantane-like arrangement. The compound is formally mixed valent with a high electrical conductivity of 9.8 × 10(5) S m(-1) at 300 K and exhibits metallic behavior having p-type charge carriers as indicated from the positive Seebeck coefficient. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 × 10(21) cm(-3) and Hall mobility of 4.5 cm(2) V(-1) s(-1) at 300 K. The electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. Band structure analysis suggests that the effective mass of the hole state is small and could be responsible for high electronic conductivity and Hall mobility. The high thermal conductivity of 15.1 W m(-1) K(-1) at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit (ZT) for this compound. Theoretical calculations indicate that if Cu5Sn2Te7 is turned into a valence precise compound by substituting one Cu by a Zn, a semiconducting material, Cu4ZnSn2Te7, with a direct band gap of ∼ 0.5 eV can be obtained.
Resumo:
Bi2Te3 based alloy nanosheet (NS)/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) composite films were prepared separately by spin coating and drop casting techniques. The drop cast composite film containing 4.10 wt % Bi2Te3 based alloy NSs showed electrical conductivity as high as 1295.21 S/cm, which is higher than that (753.8 S/cm) of a dimethyl sulfoxide doped PEDOT:PSS film prepared under the same condition and that (850-1250 S/cm) of the Bi2Te3 based alloy bulk material. The composite film also showed a very high power factor value, ∼32.26 μWm(-1) K(-2). With the content of Bi2Te3 based alloy NSs increasing from 0 to 4.10 wt %, the electrical conductivity and Seebeck coefficient of the composite films increase simultaneously.
Resumo:
This paper outlines a practice as research investigation into the construction and representation of the figure and the ground in photography through overlapping multiple temporal and spatial renderings of the same subject within single photographic images.
This included a critical investigation of the representation of time, perspective, and location in historical and contemporary photography with particular attention to the synthesis, imitation, and distinction of characteristics of human vision in this medium especially where they are indicative of consciousness and attention.
This investigation informed a re-evaluation of the premises of the genre of the photographic portrait and it’s setting, especially within the unstructured environment of the Central Victorian ironbark forests and goldfields. Analogue and digital photographic experiments were conducted in superimposed shifts in camera position and their convergence on significant points of focus through repeated exposures across different time scales. The images correspond to a stage in human stereo perception before fusion, to represent the attention of the viewer, where, in these images, the ‘portrait’ is located.
The findings were applied to the large format camera production of high-definition images that extended the range and effectiveness of selected pictorial structures such as selective focus, relative scale, superimposition, multiple exposures and interference patterns.
The outcome was an exhibition at Smrynios Gallery in Melbourne in April 2004. This presentation includes a discussion of relevant work by Australian practitioners Daniel Crooks and David Stephenson.
Resumo:
The ABS higher education attainment data has been skewed by a statistical blip that artificially inflated the 2009 figure, according to higher education researcher Alan Olsen.
Resumo:
Herein, we demonstrate that a flexible, air-permeable, thermoelectric (TE) power generator can be prepared by applying a TE polymer (e.g. poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)) coated commercial fabric and subsequently by linking the coated strips with a conductive connection (e.g. using fine metal wires). The poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated fabric shows very stable TE properties from 300 K to 390 K. The fabric device can generate a TE voltage output (V) of 4.3 mV at a temperature difference (ΔT) of 75.2 K. The potential for using fabric TE devices to harvest body temperature energy has been discussed. Fabric-based TE devices may be useful for the development of new power generating clothing and self-powered wearable electronics.
Resumo:
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