Catálogo de publicaciones - revistas

<jats:title>Scaled-up sodium-free Birch reductions</jats:title> <jats:p> The so-called Birch reduction is frequently used by chemists despite its daunting conditions: Pyrophoric sodium is dissolved in pure liquified ammonia to achieve partial reduction of aromatics. Peters <jats:italic>et al.</jats:italic> surveyed and then optimized small-scale electrochemical alternatives to devise a safer protocol that can work on a larger scale with a broad range of functionally complex substrates. </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="6429" page="838" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav5606">838</jats:related-article> </jats:p>

<jats:title>Probing the dynamics of anyons</jats:title> <jats:p> A two-dimensional electron gas in the fractional quantum Hall regime has unusual excitations called anyons that carry only a fraction of the electron's charge. This fractional charge can be observed through a dynamical response to irradiation by microwaves, but such experiments require a combination of high magnetic fields with sensitive noise measurements and very low temperatures. Kapfer <jats:italic>et al.</jats:italic> observed this dynamical response in a GaAs/AlGaAs heterostructure hosting a high-mobility two-dimensional electron gas with fractional excitations of one-third and one-fifth of the electron's charge. The method may be of interest for use in topological quantum computing. </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="6429" page="846" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aau3539">846</jats:related-article> </jats:p>

<jats:title>The key to keyhole formation</jats:title> <jats:p> The formation of keyholes, or vapor-filled depressions, during laser welding presents a large problem for additive manufacturing. Cunningham <jats:italic>et al.</jats:italic> used high-speed x-ray imaging to take a detailed look at keyhole formation in a titanium alloy. They found a simplified relationship between operational parameters and keyhole shape, which may allow for the prevention of pore formation going forward. </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="6429" page="849" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav4687">849</jats:related-article> </jats:p>

<jats:title>Coaxing quantumness in a molecular gas</jats:title> <jats:p> A dilute atomic gas cooled down to very cold temperatures can enter the so-called quantum degenerate regime, where quantum properties of the gas come to the fore. This regime has been achieved for both bosonic and fermionic atoms, but molecules, with their many internal states, present a special challenge. De Marco <jats:italic>et al.</jats:italic> cooled a bulk gas of fermionic potassium-rubidium molecules to quantum degeneracy (see the Perspective by Zelevinsky). The authors first cooled atomic potassium and rubidium gases separately, then bound them together into potassium-rubidium molecules, and finally brought the molecules down to their ground state. The density profile of the molecular gas revealed the system's quantum nature, which in turn kept the gas stable by suppressing chemical reactions. </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="6429" page="853" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aau7230">853</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6429" page="820" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aav9149">820</jats:related-article> </jats:p>