《科学》（20240816出版）一周论文导读

 
《科学》（20240816出版）一周论文导读  
 

 

编译|李言

Science, 16 AUG 2024, Volume 385 Issue 6710

《科学》2024年8月16日，第385卷，6710期

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化学Chemistry

Decoupling the air sensitivity of Na-layered oxides

解耦钠层氧化物的空气稳定性

▲ 作者：YANG YANG, ZAIFA WANG et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adm9223

▲ 摘要：

空气稳定性仍然是钠层状氧化物（NLOs）商业化的一大障碍。在此，我们表明了水蒸气只有分别与二氧化碳或氧气耦合时，在NLOs的破坏性酸降解和氧化降解中起关键作用。

定量分析表明，降低离子电位和钠含量综合影响的阳离子竞争系数(η)和增大粒径可以增强聚合物的抗酸侵蚀能力，而使用高电位氧化还原对可以消除氧化降解。这些发现阐明了潜在的空气恶化机制，并使空气稳定NLOs的设计合理化。

▲ Abstract：

Air sensitivity remains a substantial barrier to the commercialization of sodium (Na)–layered oxides (NLOs). We show here that water vapor plays a pivotal role in initiating destructive acid and oxidative degradations of NLOs only when coupled with carbon dioxide or oxygen, respectively. Quantification analysis revealed that reducing the defined cation competition coefficient (η), which integrates the effects of ionic potential and sodium content, and increasing the particle size can enhance the resistance to acid attack, whereas using high-potential redox couples can eliminate oxidative degradation. These findings elucidate the underlying air deterioration mechanisms and rationalize the design of air-stable NLOs.

天文学Astronomy

Ruthenium isotopes show the Chicxulub impactor was a carbonaceous-type asteroid

钌同位素表明希克苏鲁伯陨石是一颗碳质小行星

▲ 作者：MARIO FISCHER-G?DDE, JONAS TUSCH et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adk4868

▲ 摘要：

6600万年前发生在墨西哥希克苏鲁伯的一次陨石撞击，产生了一个标志着白垩纪和古近纪分界线的地层。这一地层含有高浓度的铂族元素，包括钌。

我们测量了三个白垩纪—古近纪边界地点的样品中的钌同位素，另外五个发生在3600万到4.7亿年前的撞击，以及35亿到32亿年前的撞击球体层。我们的数据表明，希克苏鲁伯撞击物是一颗形成于木星轨道之外的碳质小行星。

另外五个撞击结构的同位素特征与形成于离太阳更近的地方的硅质小行星更一致。太古宙球粒层样品与地球吸积最后阶段含碳小行星的撞击相一致。

▲ Abstract：

An impact at Chicxulub, Mexico, occurred 66 million years ago, producing a global stratigraphic layer that marks the boundary between the Cretaceous and Paleogene eras. That layer contains elevated concentrations of platinum-group elements, including ruthenium. We measured ruthenium isotopes in samples taken from three Cretaceous-Paleogene boundary sites, five other impacts that occurred between 36 million to 470 million years ago, and ancient 3.5-billion- to 3.2-billion-year-old impact spherule layers. Our data indicate that the Chicxulub impactor was a carbonaceous-type asteroid, which had formed beyond the orbit of Jupiter. The five other impact structures have isotopic signatures that are more consistent with siliceous-type asteroids, which formed closer to the Sun. The ancient spherule layer samples are consistent with impacts of carbonaceous-type asteroids during Earth’s final stages of accretion.

物理学Physics

Quantum state tracking and control of a single molecular ion in a thermal environment

热环境中单个分子离子的量子态跟踪与控制

▲ 作者：YU LIU, JULIAN SCHMIDT et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ado1001

▲ 摘要：

在此，我们报告单个分子在不同状态（“跳跃”）之间的热辐射驱动转换的实时观察。我们通过微波驱动的转变逆转了这些“跳跃”，使得分子停留在选定状态的时间延长了20倍。