Catálogo de publicaciones - revistas

<jats:title>Cylindrical polymer micelles pack in 3D</jats:title> <jats:p> When you control chemistry, solvents, temperature, and concentration, surfactants and block copolymers will readily assemble into micelles, rods, and other structures. Qiu <jats:italic>et al.</jats:italic> take this to new lengths through precise selection of longer polymer blocks that self-assemble through a crystallization process (see the Perspective by Lee <jats:italic>et al.</jats:italic> ). They chose polymer blocks that were either hydrophobic or polar and used miscible solvents that were each ideal for only one of the blocks. Their triblock comicelles generated a wide variety of stable three-dimensional superstructures through side-by-side stacking and end-to-end intermicellar association. </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="6228" page="1329" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1261816">1329</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6228" page="1310" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.aaa8681">1310</jats:related-article> </jats:p>

<jats:title>Sunspot cycle driven by linked fields</jats:title> <jats:p> Sunspots indicate magnetic flux emerging at the Sun's surface. Sunspots change over an 11-year time scale, which depends on the behavior of the probable magnetic dynamo within. Cameron <jats:italic>et al.</jats:italic> suggest that the flux revealed by sunspot activity is effectively driven by the magnetic field strength at the Sun's poles. Their mathematical reasoning explains why the polar field activity can predict the sunspot cycle. </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="6228" page="1333" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1261470">1333</jats:related-article> </jats:p>

<jats:title>Picking out the elusive stripes</jats:title> <jats:p> Copper-oxide superconductors have periodic modulations of charge density. Typically, the modulation is not the same for the whole crystal, but breaks up into small nanosized domains. Bulk experiments show that the density is modulated along both axes in the copper-oxide plane, but it is not clear whether this is true only on the scale of the whole crystal or also locally, for each domain. Comin <jats:italic>et al.</jats:italic> analyzed the charge order in the compound YBa <jats:sub>2</jats:sub> Cu <jats:sub>3</jats:sub> O <jats:sub>6+y</jats:sub> , using resonant x-ray scattering, and found that it was consistent with a local unidirectional, so-called stripy, ordering. </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="6228" page="1335" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1258399">1335</jats:related-article> </jats:p>

<jats:title>Uncovering the symmetry of a hidden order</jats:title> <jats:p> Cooling matter generally makes it more ordered and may induce dramatic transitions: Think of water becoming ice. With increased order comes loss of symmetry; water in its liquid form will look the same however you rotate it, whereas ice will not. Kung <jats:italic>et al.</jats:italic> studied the symmetry properties of a mysteriously ordered phase of the material URu <jats:sub>2</jats:sub> Si <jats:sub>2</jats:sub> that appears at 17.5 K. They shone laser light on the crystal and studied the shifts in the frequency of the light. The electron orbitals of the uranium had a handedness to them that alternated between the atomic layers. </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="6228" page="1339" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.1259729">1339</jats:related-article> </jats:p>

<jats:title>Color correcting planar optics</jats:title> <jats:p> The functionality of many bulk optical elements can now be replaced by specially designed structures fabricated in thin films. This planar optics approach, however, has generally been applicable to only a narrow band of wavelengths. Aieta <jats:italic>et al.</jats:italic> show that chromatic dispersion, or color dependence, can be compensated for by the judicious design of the surface. The results demonstrate a general approach for the fabrication of broadband and lightweight optical elements that can be engineered into planar thin films. </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="6228" page="1342" related-article-type="in-this-issue" vol="347" xlink:href="10.1126/science.aaa2494">1342</jats:related-article> </jats:p>