《科学》（20211015出版）一周论文导读

编译 冯维维

Science , 15 OCTOBER 2021, Volume 374, Issue 6565

《科学》 2021年10月15日，第374卷，6565期

物理学 Physics

A compositional link between rocky exoplanets and their host stars

系外岩质行星和主恒星之间的组成关联

作者：Vardan Adibekyan, Caroline Dorn, Sérgio G. Sousa, Nuno C. Santos, Bertram Bitsch, Garik Israelian, Christoph Mordasini, etc.

链接：

https://www.science.org/doi/10.1126/science.abg8794

摘要

恒星和行星都是通过从周围的圆盘中吸积物质而形成的。因为它们是由相同的物质生长而来，所以理论预测其组成之间应该有一定的关系。作者探寻了系外岩石行星与其主恒星之间的成分联系。

他们从岩石系外行星的质量和半径来估计其铁质量分数，并将其与其主恒星的组成进行比较，假设主恒星反映了原行星盘的组成。他们发现这两个量之间存在相关性（但不是1:1的关系），其斜率>4，将其解释为可归因于行星形成过程。

作者表示，“超级地球”和“超级水星”似乎是不同的类型，组成成分不同，这意味着它们的形成过程不同。

Abstract

Stars and planets both form by accreting material from a surrounding disk. Because they grow from the same material, theory predicts that there should be a relationship between their compositions. In this study, we search for a compositional link between rocky exoplanets and their host stars. We estimate the iron-mass fraction of rocky exoplanets from their masses and radii and compare it with the compositions of their host stars, which we assume reflect the compositions of the protoplanetary disks. We find a correlation (but not a 1:1 relationship) between these two quantities, with a slope of >4, which we interpret as being attributable to planet formation processes. Super-Earths and super-Mercuries appear to be distinct populations with differing compositions, implying differences in their formation processes.

Electrically tunable Feshbach resonances in twisted bilayer semiconductors

双层扭曲半导体中的电可调谐费什巴赫共振

作者：IDO SCHWARTZ, YUYA SHIMAZAKI, CLEMENS KUHLENKAMP, KENJI WATANABE, TAKASHI TANIGUCHI, MARTIN KRONER, AND ATAÇ IMAMOĞLU

链接：

https://www.science.org/doi/10.1126/science.abj3831

摘要

过渡金属二卤素双分子层中的莫尔超晶格为研究与光谱学的强相关性提供了一个平台，尽管观察到丰富的Mott-Wigner物理源于周期势和库仑相互作用，没有隧道耦合诱导的电子态杂化确保了经典层自由度。

作者研究了MoSe2同质层结构，其中层间相干隧穿允许电场控制 *** 纵和基态空穴层赝自旋的测量。作者在激子-空穴散射中观察到一个电可调的二维费什巴赫共振，这使他们能够控制位于不同层中的激子和空穴之间的相互作用强度。

作者表示，该结果可能使具有可调谐相互作用的简并玻色费米混合物的实现成为可能。

Abstract

Moiré superlattices in transition metal dichalcogenide bilayers provide a platform for exploring strong correlations with optical spectroscopy. Despite the observation of rich Mott-Wigner physics stemming from an interplay between the periodic potential and Coulomb interactions, the absence of tunnel coupling–induced hybridization of electronic states has ensured a classical layer degree of freedom. We investigated a MoSe2 homobilayer structure where interlayer coherent tunneling allows for electric field–controlled manipulation and measurement of the ground-state hole-layer pseudospin. We observed an electrically tunable two-dimensional Feshbach resonance in exciton-hole scattering, which allowed us to control the strength of interactions between excitons and holes located in different layers. Our results may enable the realization of degenerate Bose-Fermi mixtures with tunable interactions.

The Gulf Stream and Kuroshio Current are synchronized

墨西哥湾流和黑潮流是同步的

作者：TSUBASA KOHYAMA, YOKO YAMAGAMI, HIROAKI MIURA , SHOICHIRO KIDO , HIROAKI TATEBE

链接：

https://www.science.org/doi/10.1126/science.abh3295

摘要

墨西哥湾流和黑潮分别是西大西洋和太平洋的大型表层边界流。它们将热量从热带地区输送到温带地区，并影响整个北半球的海面温度、天气和气候。

作者将卫星观测和模式实验相结合，表明这两种气流在年代际时间尺度上通过大气急流的经向迁移同步。这种耦合有助于解释诸如2018年北半球温带异常炎热的夏季等气候事件。

Abstract

The Gulf Stream and the Kuroshio are the large surface boundary currents in the western Atlantic and Pacific Oceans, respectively. They transport heat from the tropics to the extratropics and influence sea surface temperature, weather, and climate throughout the Northern Hemisphere. Kohyama et al. combined satellite observations with model experiments to show that these two currents are synchronized on decadal time scales by the meridional migration of the atmospheric jet stream. This coupling can help to explain climate events such as the abnormally hot summer of 2018 in the Northern Hemispheric extratropics.

化学 Chemistry

Univariate classification of phosphine ligation state and reactivity in cross-coupling catalysis

交叉偶联催化中膦连接态和反应活性的单变量分类

作者：SAMUEL H. NEWMAN-STONEBRAKER, SLEIGHT R. SMITH, XJULIA E. BOROWSKI, ELLYN PETERS, TOBIAS GENSCH, HEATHER C. JOHNSON, MATTHEW S. SIGMAN, AND ABIGAIL G. DOYLE

链接：

https://www.science.org/doi/10.1126/science.abj4213

摘要

与钯、镍配合的膦配体是组装药物化合物主干的重要工具。几十年来，描述空间体积的描述符有助于指导磷化氢的优化。然而，这些描述符往往适用于单个配体的理想几何形状。

Newman-Stonebraker等人引入了一种描述子，考虑配体的构象如何在拥挤的环境中改变。具体来说，他们发现最小埋入体积百分比准确地预测了一两个特定配体何时会与金属中心配位，这通常是催化成功的关键决定因素。

Abstract

Phosphine ligands coordinated to palladium and nickel are essential tools for assembling the backbones of pharmaceutical compounds. For decades, descriptors that characterize spatial bulk have helped to guide phosphine optimization. However, these descriptors tend to apply to ideal geometries of a single ligand. Newman-Stonebraker et al. introduce a descriptor that considers how the ligand conformation might change in a crowded environment. Specifically, they found that the minimum percentage buried volume accurately predicts when one or two of a particular ligand will coordinate to a metal center, frequently a key determinant of successful catalysis.

A priori control of zeolite phase competition and intergrowth with high-throughput simulations

沸石合成中的选择性控制

作者：DANIEL SCHWALBE-KODA, ZACH JENSENELSA OLIVETTI, TOM WILLHAMMAR, VELINO CORMA , YURIY ROMÁN-LESHKOV , RAFAEL GÓMEZ-BOMBARELLI, etc.

链接：

https://www.science.org/doi/10.1126/science.abh3350

摘要

沸石广泛应用于许多工业应用，但尽管几十年的研究，其合成仍然依赖于试错方法。复杂的成核机制和拓扑多样性导致了强烈的相竞争，使沸石合成的合理设计问题复杂化。

作者利用原子模拟、文献挖掘、人机交互、合成和表征，开发了一种计算策略，能够预先控制沸石合成中的相选择性。这种方法使用了几个指标来设计有机结构导向剂，以控制相竞争和共生的目标沸石结晶。

如果这种方法能成功地合成实用的不常见沸石，该结果将对材料科学界产生深远的影响。

Abstract

Zeolites are widely used in many industrial applications, but despite decades of research, their synthesis still relies on trial-and-error approaches. Complex nucleation mechanisms and topological persity lead to strong phase competition, complicating the issue of rational design of zeolite synthesis. Using atomistic simulations, literature mining, human-computer interaction, synthesis, and characterization, Schwalbe-Koda et al. developed a computational strategy that enables a priori control of phase selectivity in zeolite synthesis. This approach uses several metrics for designing organic structure–directing agents to crystallize target zeolites with controlled phase competition and intergrowth. These results may have profound implications for the materials science community if this method is shown to be successful in the synthesis of practically useful uncommon zeolites.

生态学 Ecology

Physical disturbance by recovering sea otter populations increases eelgrass genetic persity

海獭数量的恢复增加了大叶藻的遗传多样性

作者：ERIN FOSTER, JANE WATSON, MATTHEW A. LEMAY, M. TIM TINKER, XJAMES A. ESTES , CAROL, CHRIS T. DARIMONT

链接：

https://www.science.org/doi/10.1126/science.abf2343

摘要

在过去几十年里，对海獭的研究改变了人们对特定物种或关键物种重要性的理解，因为它们是群落结构和稳定性的驱动因素。作者测试了水獭的觅食是否会影响大叶藻生态系统的遗传多样性。

结果发现，水獭存在的地方，大叶藻的遗传多样性明显更高，而且这种影响与时间有关：水獭存在的时间越长，遗传多样性就越高。

作者表示，这些结果说明了在热带生态系统中，捕食者的行为如何影响生产者的多样性。

Abstract

Work in sea otters over the last few decades has transformed our understanding of the importance of specific species, or keystones, as drivers of community structure and stability. Foster et al. took the next step and tested whether otter foraging might influence genetic persity in an eelgrass ecosystem (see the Perspective by Roman). The authors found that eelgrass genetic persity was significantly higher where otters were present and that the impact was related to time: Longer otter presence was associated with higher genetic persity. These results illustrate how the actions of a predator can affect the persity of a producer in a tropic system.

一种将交流电能转变为直流电能的半导体器件。通常它包含一个PN结，有正极和负极两个端子。二极管最重要的特性就是单方向导电性。在电路中，电流只能从二极管的正极流入，负极流出。整流二极管(rectifier diode)一种用于将交流电转变为直流电的半导体器件。整流二极管一般为平面型硅二极管，用于各种电源整流电路中。开关稳压电源的整流电路及脉冲整流电路中使用的整流二极管，应选用工作频率较高、反向恢复时间较短的整流二极管（例如RU系列、EU系列、V系列、1SR系列等）或选择快恢复二极管。整流二极管损坏后，可以用同型号的整流二极管或参数相贩其它型号整流二极管代换。

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