Catálogo de publicaciones - revistas

<jats:title>Light with twist and structure</jats:title> <jats:p> Möbius strips are three-dimensional structures consisting of a surface with just a single side. Readily demonstrated by snipping a paper ring, adding a twist, and then joining the ends of paper together again, these structures have intriguing mathematical properties in terms of topology and geometry. Bauer <jats:italic>et al.</jats:italic> used a liquid crystal to engineer the wavefront of a laser beam to make an optical version of the Möbius strip by effectively “snipping and twisting” the polarization properties of the light beam. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6225" page="964" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1260635">964</jats:related-article> </jats:p>

<jats:title>Balanced carrier diffusion in perovskites</jats:title> <jats:p> The efficient operation of solar cells based on inorganic-organic perovskites requires balanced transport of positive and negative charge carriers over long distances. Dong <jats:italic>et al.</jats:italic> used a top-seeded solution growth method to obtain millimeter-scale single crystals of the organolead trihalide perovskite CH <jats:sub>3</jats:sub> NH <jats:sub>3</jats:sub> PbI <jats:sub>3</jats:sub> . Under low light illumination, the electron and hole diffusion lengths exceeded 3 mm, and under full sunlight illumination, they exceeded 175 µm. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6225" page="967" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.aaa5760">967</jats:related-article> </jats:p>

<jats:title>An enduring catalyst built from carbon</jats:title> <jats:p> Splitting water into its constituent elements, hydrogen and oxygen, generally requires the assistance of metal catalysts. Liu <jats:italic>et al.</jats:italic> now show that a metal-free hybrid material composed of carbon and nitrogen can promote this reaction all on its own, with the help of some visible light. The photocatalyst combines one material (C <jats:sub>3</jats:sub> N <jats:sub>4</jats:sub> ) known to split water into hydrogen and peroxide with a second material (CDot) that breaks the peroxide down before it can damage the first. The robust stability of this hybrid bodes well for practical implementation of optimized analogs in solar energy storage schemes. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6225" page="970" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.aaa3145">970</jats:related-article> </jats:p>

<jats:title>Shocking! Particle accelerators in space</jats:title><jats:p>The acceleration of charged particles to high energies has been a major mystery, with a number of competing theories based on plasma physics. Many include the concept of turbulence, but with different roles. For example, shock-based theories emphasize the importance of turbulence developed from an unstable shock layer, whereas turbulent reconnection theories emphasize interactions of multiple reconnection sites. Matsumoto<jats:italic>et al.</jats:italic>present results of a large particle-in-cell simulation and examine how electrons are accelerated in the transition layer of a fast nonrelativistic shock (see the Perspective by Ji and Zweibel). Surprisingly, they find that when the shock is strong enough, charged particles (electrons in this case) are efficiently accelerated by turbulent reconnection within a turbulent shock layer containing multiscale structures.</jats:p><jats:p><jats:italic>Science</jats:italic>, this issue p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6225" page="974" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1260168">974</jats:related-article>; see also p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6225" page="944" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.aaa3036">944</jats:related-article></jats:p>

<jats:title>Catching CO oxidation</jats:title> <jats:p> Details of the transition state that forms as carbon monoxide (CO) adsorbed on a ruthenium surface is oxidized to CO <jats:sub>2</jats:sub> have been revealed by ultrafast excitation and probe methods. Öström <jats:italic>et al.</jats:italic> initiated the reaction between CO and adsorbed oxygen atoms with laser pulses that rapidly heated the surface and then probed the changes in electronic structure with oxygen x-ray absorption spectroscopy. They observed transition-state configurations that are consistent with density functional theory and a quantum oscillator model. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6225" page="978" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1261747">978</jats:related-article> </jats:p>