GSTDTAP

浏览/检索结果: 共4条,第1-4条 帮助

已选(0)清除 条数/页:   排序方式:
Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration 期刊论文
NATURE COMMUNICATIONS, 2020, 11 (1)
作者:  Hocknull, Scott A.;  Lewis, Richard;  Arnold, Lee J.;  Pietsch, Tim;  Joannes-Boyau, Renaud;  Price, Gilbert J.;  Moss, Patrick;  Wood, Rachel;  Dosseto, Anthony;  Louys, Julien;  Olley, Jon;  Lawrence, Rochelle A.
收藏  |  浏览/下载:12/0  |  提交时间:2020/05/20
Iron-based binary ferromagnets for transverse thermoelectric conversion 期刊论文
NATURE, 2020, 581 (7806) : 53-+
作者:  Grun, Rainer;  Pike, Alistair;  McDermott, Frank;  Eggins, Stephen;  Mortimer, Graham;  Aubert, Maxime;  Kinsley, Lesley;  Joannes-Boyau, Renaud;  Rumsey, Michael;  Denys, Christiane;  Brink, James;  Clark, Tara;  Stringer, Chris
收藏  |  浏览/下载:31/0  |  提交时间:2020/07/03

Aluminium- and gallium-doped iron compounds show a large anomalous Nernst effect owing to a topological electronic structure, and their films are potentially suitable for designing low-cost, flexible microelectronic thermoelectric generators.


Thermoelectric generation using the anomalous Nernst effect (ANE) has great potential for application in energy harvesting technology because the transverse geometry of the Nernst effect should enable efficient, large-area and flexible coverage of a heat source. For such applications to be viable, substantial improvements will be necessary not only for their performance but also for the associated material costs, safety and stability. In terms of the electronic structure, the anomalous Nernst effect (ANE) originates from the Berry curvature of the conduction electrons near the Fermi energy(1,2). To design a large Berry curvature, several approaches have been considered using nodal points and lines in momentum space(3-10). Here we perform a high-throughput computational search and find that 25 percent doping of aluminium and gallium in alpha iron, a naturally abundant and low-cost element, dramatically enhances the ANE by a factor of more than ten, reaching about 4 and 6 microvolts per kelvin at room temperature, respectively, close to the highest value reported so far. The comparison between experiment and theory indicates that the Fermi energy tuning to the nodal web-a flat band structure made of interconnected nodal lines-is the key for the strong enhancement in the transverse thermoelectric coefficient, reaching a value of about 5 amperes per kelvin per metre with a logarithmic temperature dependence. We have also succeeded in fabricating thin films that exhibit a large ANE at zero field, which could be suitable for designing low-cost, flexible microelectronic thermoelectric generators(11-13).


  
Oceanic forcing of penultimate deglacial and last interglacial sea-level rise 期刊论文
NATURE, 2020, 577 (7792) : 660-+
作者:  Rizal, Yan;  Westaway, Kira E.;  Zaim, Yahdi;  van den Bergh, Gerrit D.;  Bettis, E. Arthur, III;  Morwood, Michael J.;  Huffman, O. Frank;  Grun, Rainer;  Joannes-Boyau, Renaud;  Bailey, Richard M.;  Sidarto;  Westaway, Michael C.;  Kurniawan, Iwan;  Moore, Mark W.;  Storey, Michael;  Aziz, Fachroel;  Suminto;  Zhao, Jian-xin;  Aswan;  Sipola, Maija E.;  Larick, Roy;  Zonneveld, John-Paul;  Scott, Robert;  Putt, Shelby;  Ciochon, Russell L.
收藏  |  浏览/下载:20/0  |  提交时间:2020/05/13

Sea-level histories during the two most recent deglacial-interglacial intervals show substantial differences(1-3) despite both periods undergoing similar changes in global mean temperature(4,5) and forcing from greenhouse gases(6). Although the last interglaciation (LIG) experienced stronger boreal summer insolation forcing than the present interglaciation(7), understanding why LIG global mean sea level may have been six to nine metres higher than today has proven particularly challenging(2). Extensive areas of polar ice sheets were grounded below sea level during both glacial and interglacial periods, with grounding lines and fringing ice shelves extending onto continental shelves(8). This suggests that oceanic forcing by subsurface warming may also have contributed to ice-sheet loss(9-12) analogous to ongoing changes in the Antarctic(13,14) and Greenland(15) ice sheets. Such forcing would have been especially effective during glacial periods, when the Atlantic Meridional Overturning Circulation (AMOC) experienced large variations on millennial timescales(16), with a reduction of the AMOC causing subsurface warming throughout much of the Atlantic basin(9,12,17). Here we show that greater subsurface warming induced by the longer period of reduced AMOC during the penultimate deglaciation can explain the more-rapid sea-level rise compared with the last deglaciation. This greater forcing also contributed to excess loss from the Greenland and Antarctic ice sheets during the LIG, causing global mean sea level to rise at least four metres above modern levels. When accounting for the combined influences of penultimate and LIG deglaciation on glacial isostatic adjustment, this excess loss of polar ice during the LIG can explain much of the relative sea level recorded by fossil coral reefs and speleothems at intermediate- and far-field sites.


  
Elemental signatures of Australopithecus africanus teeth reveal seasonal dietary stress 期刊论文
NATURE, 2019, 572 (7767) : 112-+
作者:  Joannes-Boyau, Renaud;  Adams, Justin W.;  Austin, Christine;  Arora, Manish;  Moffat, Ian;  Herries, Andy I. R.;  Tonge, Matthew P.;  Benazzi, Stefano;  Evans, Alistair R.;  Kullmer, Ottmar;  Wroe, Stephen;  Dosseto, Anthony;  Fiorenza, Luca
收藏  |  浏览/下载:6/0  |  提交时间:2019/11/27