天文学Astronomy Isotopic evidence of long-lived volcanism on Io 木卫一持久火山勾当的同位素证据 ▲ 作者：KATHERINE DE KLEER, ERY C. HUGHES, FRANCIS NIMMO, JOHN EILER, AMY E. HOFMANN, STATIA LUSZCZ-COOK, ET AL. ▲ 链接： https://www.science.org/doi/10.1126/science.adj0625 ▲ 摘要： 木卫一上有年夜量的火山勾当，由潮汐加热驱动。木卫一挥发性化学元素（包罗硫和氯）的同位素构成反应了其放气和质量损掉的汗青，从而记实了演变信息。 研究组操纵对木卫一年夜气层的亚毫米不雅测来丈量气态二氧化硫和一氧化硫中的硫同位素，和气态氯化钠和氯化钾中的氯同位素。 成果发现34S/32S = 0.0595 0.0038（相当在 34S = +347 86 ），与太阳系的平均值比拟高度富集，这注解木卫一已损掉了94~99%的可用硫。丈量还发现37Cl/35Cl = 0.403 0.028（ 37Cl = +263 88 ），注解氯也一样富集。 这些成果注解，木卫一在其年夜部门（或全数）汗青中都有火山勾当，初期可能有更高的放气率和质量损掉率。 ▲ Abstract： Jupiter s moon Io hosts extensive volcanism, driven by tidal heating. The isotopic composition of Io s inventory of volatile chemical elements, including sulfur and chlorine, reflects its outgassing and mass-loss history and thus records information about its evolution. We used submillimeter observations of Io s atmosphere to measure sulfur isotopes in ga搜索引擎优化us sulfur dioxide and sulfur monoxide, and chlorine isotopes in ga搜索引擎优化us sodium chloride and potassium chloride. We find 34S/32S = 0.0595 0.0038 (equivalent to 34S = +347 86 ), which is highly enriched compared to average Solar System values and indicates that Io has lost 94 to 99% of its available sulfur. Our measurement of 37Cl/35Cl = 0.403 0.028 ( 37Cl = +263 88 ) shows that chlorine is similarly enriched. These results indicate that Io has been volcanically active for most (or all) of its history, with potentially higher outgassing and mass-loss rates at earlier times. 材料科学Materials Science Catalog of topological phonon materials 拓扑声子材料目次 ▲ 作者：YUANFENG XU, M. G. VERGNIORY, DA-SHUAI MA, JUAN L. MA?ES, ZHI-DA SONG, B. ANDREI BERNEVIG, ET AL. ▲ 链接： https://www.science.org/doi/10.1126/science.adf8458 ▲ 摘要： 声子在固态系统的很多特征中起着相当主要的感化，人们期望拓扑声子可致使丰硕和很是规的物理特征。 在现有声子材料数据库的根本上，研究组汇编了1万多种三维晶体材料的拓扑声子带目次。操纵拓扑量子化学计较了声子数据库中材料的每组孤立声子带的能带暗示、兼容关系和能带拓扑。 另外还计较了所有拓扑普通带的实空间不变量，并将其分类为原子能带或受阻原子能带。研究组已选择了1000多种 抱负 的非普通声子材料用在将来尝试阐发开博体育。这些数据集将被用在成立拓扑声子数据库。 ▲ Abstract： Phonons play a crucial role in many properties of solid-state systems, and it is expected that topological phonons may lead to rich and unconventional physics. On the basis of the existing phonon materials databases, we have compiled a catalog of topological phonon bands for more than 10,000 three-dimensional crystalline materials. Using topological quantum chemistry, we calculated the band representations, compatibility relations, and band topologies of each isolated set of phonon bands for the materials in the phonon databases. Additionally, we calculated the real-space invariants for all the topologically trivial bands and classified them as atomic or obstructed atomic bands. We have selected more than 1000 ideal nontrivial phonon materials to motivate future experiments. The datasets were used to build the Topological Phonon Database. The odd-number cyclo[13]carbon and its dimer, cyclo[26]carbon 奇数环[13]碳和其二聚体环[26]碳 ▲ 作者：FLORIAN ALBRECHT, IGOR RON?EVI?, YUEZE GAO, FABIAN PASCHKE, ALBERTO BAIARDI, IVANO TAVERNELLI, ET AL. ▲ 链接： https://www.science.org/doi/10.1126/science.ado1399 ▲ 摘要： N个碳原子的份子环（环[N]碳，或CN）是测试量子化学理论方式的优异基准系统，也是其他富碳材料有价值的前体。奇数 N环碳迄今为止一向难以捉摸，估计比偶数 N环碳更不不变。 研究组报导了用扫描探针显微镜尖端把持十氯芴在概况合成环[13]碳，C13。经由过程尝试和理论摹拟表征了C13的性质。C13采取三重态基态和扭结几何布局的开壳构型，按照份子情况的分歧表示出分歧水平的扭曲和卡宾局域化。 另外，研究组制备并表征了C13二聚体，即环[26]碳，证实了环碳和其前体作为碳同素异形体构建块的潜力。 ▲ Abstract： Molecular rings of N carbon atoms (cyclo[N]carbons, or CN) are excellent benchmarking systems for testing quantum chemical theoretical methods and valuable precursors to other carbon-rich materials. Odd-N cyclocarbons, which have been elusive to date, are predicted to be even less stable than even-N cyclocarbons. We report the on-surface synthesis of cyclo[13]carbon, C13, by manipulation of decachlorofluorene with a scanning probe microscope tip. We elucidated the properties of C13 by experiment and theoretical modeling. C13 adopts an open-shell configuration with a triplet ground state and a kinked geometry, which shows different extents of distortion and carbene localization depending on the molecular environment. Moreover, we prepared and characterized the C13 dimer, cyclo[26]carbon, demonstrating the potential of cyclocarbons and their precursors as building blocks for carbon allotropes. 化学Chemistry Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis MnO2还原的原子分离六价氧化铱助力析氧催化 ▲ 作者：AILONG LI, SHUANG KONG, KIYOHIRO ADACHI, HIDESHI OOKA, KAZUNA FUSHIMI, QIKE JIANG, ET AL. ▲ 链接： https://www.science.org/doi/10.1126/science.adg5193 ▲ 摘要： 人们猜测六价氧化铱（IrVI）在酸中的析氧反映中比其他氧化铱更具活性、更不变；但是其尝试实现仍颇具挑战性。 研究组报导了用在质子互换膜（PEM）水电解的原子分离IrVI氧化物（IrVI-ado）的合成、表征和利用。用氧化锰（MnO2）氧化代替六氯铱酸钾（K2IrCl6）配体，合成了IrVI-ado。 IrVI-ado的质量比活度（1.7 105 A/gIr）和周转率（1.5 108）跨越了基准铱氧化物，PEM操作时代的原位X射线阐发注解，IrVI在电流密度高达2.3 A/cm2时仍具有经久性。IrVI-ado的高活性和不变性显示了其作为PEM电解阳极材料的前景。 ▲ Abstract： Hexavalent iridium (IrVI) oxide is predicted to be more active and stable than any other iridium oxide for the oxygen evolution reaction in acid; however, its experimental realization remains challenging. In this work, we report the synthesis, characterization, and application of atomically dispersed IrVI oxide (IrVI-ado) for proton exchange membrane (PEM) water electrolysis. The IrVI-ado was synthesized by oxidatively substituting the ligands of potassium hexachloroiridate(IV) (K2IrCl6) with manganese oxide (MnO2). The mass-specific activity (1.7 105 amperes per gram of iridium) and turnover number (1.5 108) exceeded those of benchmark iridium oxides, and in situ x-ray analysis during PEM operations manifested the durability of IrVI at current densities up to 2.3 amperes per square centimeter. The high activity and stability of IrVI-ado showcase its promise as an anode material for PEM electrolysis. Scalable decarboxylative trifluoromethylation by ion-shielding heterogeneous photoelectrocatalysis 离子屏障非均相光电催化助力可扩大脱羧三氟甲基化 ▲ 作者：YIXIN CHEN, YUCHEN HE, YONG GAO, JIAKUN XUE, WEI QU, JUN XUAN AND YIMING MO ▲ 链接： https://www.science.org/doi/10.1126/science.adm8902 ▲ 摘要： 电化学为增值邃密化学品供给了可延续的合成路子，但凡是遭到电极和分歧在靶位点的氧化还原敏感功能性之间竞争电子转移的限制。 研究组描写了一种离子屏障的非均相光电催化策略，以施加传质限制，从而逆转了热力学决议的电子转移挨次。利用三氟乙酸盐（一种便宜但相对惰性的三氟甲基（CF3）源）展现了该策略可实现敏感（杂）芳烃的脱羧三氟甲基化。 由三氟乙酸根阴离子静电吸附在正钼搀杂的三氧化钨（WO3）光阳极上构成的离子屏障层，可避免基底和光生空穴之间无益的电子转移。经由过程操纵光电化学活动电池实现稳健的光阳极不变性（约380小时）、杰出的基底规模，和100克合成的可扩大能力，充实证实了该策略的适用性。 ▲ Abstract： Electrochemistry offers a sustainable synthesis route to value-added fine chemicals but is often constrained by competing electron transfer between the electrode and redox-sensitive functionalities distinct from the target site. Here, we describe an ion-shielding heterogeneous photoelectrocatalysis strategy to impose mass-transfer limitations that invert the thermodynamically determined order of electron transfer. This strategy is showcased to enable decarboxylative trifluoromethylation of sensitive (hetero)arenes by using trifluoroacetate, an inexpensive yet relatively inert trifluoromethyl group (CF3) source. An ion-shielding layer, formed by trifluoroacetate anions electrostatically adsorbed on a positive molybdenum-doped tungsten trioxide (WO3) photoanode, prevents undesired electron transfer between substrates and photogenerated holes. The practicality of the developed method was demonstrated with robust photoanode stability (approximately 380 hours), a good substrate scope, and scaling capability to achieve 100-gram synthesis by using photoelectrochemical flow cells. 地球科学Earth Science A diminished North Atlantic nutrient stream during Younger Dryas climate reversal 新仙女木期天气逆转时代北年夜西洋营养流削减 ▲ 作者：JEAN LYNCH-STIEGLITZ, TYLER D. VOLLMER, SHANNON G. VALLEY, ERIC BLACKMON, SIFAN GU AND THOMAS M. MARCHITTO ▲ 链接： https://www.science.org/doi/10.1126/science.adi5543 ▲ 摘要： 北年夜西洋的高生物出产力由经由过程墨西哥湾流（营养流）向该地域平流供给的营养物资所刺激。有人提出，估计将来年夜西洋经向翻转环流（AMOC）的降落将致使营养物资供给削减，从而致使出产力降落。 研究组阐发了标记着从末次冰期过渡的新仙女木期天气逆转时代营养流是若何转变的。在AMOC削弱时代，佛罗里达海峡的墨西哥湾流营养物资含量降落，氧含量增添。营养流的削减陪伴着北年夜西洋高纬度地域生物出产力的降落，这撑持了理论和建模研究中所假定的联系。 ▲ Abstract： The high rate of biological productivity in the North Atlantic is stimulated by the advective supply of nutrients into the region via the Gulf Stream (nutrient stream). It has been proposed that the projected future decline in the Atlantic Meridional Overturning Circulation (AMOC) will cause a reduction in nutrient supply and resulting productivity. In this work, we examine how the nutrient stream changed over the Younger Dryas climate reversal that marked the transition out of the last ice age. Gulf Stream nutrient content decreased, and oxygen content increased at the Florida Straits during this time of weakened AMOC. The decreased nutrient stream was accompanied by a reduction in biological productivity at higher latitudes in the North Atlantic, which supports the link postulated in theoretical and modeling studies.特殊声明：本文转载仅仅是出在传布信息的需要，其实不意味着代表本网站不雅点或证实其内容的真实性；如其他媒体、网站或小我从本网站转载利用，须保存本网站注明的“来历”，并自大版权等法令责任；作者假如不但愿被转载或联系转载稿费等事宜，请与我们联系。
