编译|未玖

Science, 14 MAR 2025, VOL 387, ISSUE 6739

《科学》2025年3月14日，第387卷，6739期

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天文学Astronomy

Three-dimensional maps of the interstellar dust extinction curve within the Milky Way galaxy

银河系内星际尘埃消光曲线的三维图

▲ 作者：XIANGYU ZHANG AND GREGORY M. GREEN

▲链接：

https://www.science.org/doi/10.1126/science.ado9787

▲摘要：

星际尘埃颗粒通过吸收和散射导致背景天文光源的光消光。消光曲线的光谱形状取决于尘埃的组成。

研究组用低分辨率光谱测量了1.3亿颗恒星的消光曲线。通过反演这些数据，绘制了银河系内三维和麦哲伦星云内二维的消光曲线参数R(V)。这些地图为天文观测提供了改良的消光校正工具。

研究组发现R(V)随消光而变化，与低消光区尘埃颗粒的吸积生长和高消光区尘埃颗粒的凝聚生长相一致。恒星形成区域的R(V)值较高，表明这些区域要么优先破坏小尘埃颗粒，要么额外供应大尘埃颗粒。

▲ Abstract：

Interstellar dust grains cause extinction (absorption and scattering) of light from background astronomical sources. The spectral shape of the extinction curve depends on the dust composition. We used low-resolution optical spectra to measure the extinction curve of 130 million stars. By inverting these data, we mapped the extinction curve parameter R(V) within the Milky Way in three dimensions and within the Magellanic Clouds in two dimensions. These maps provide improved extinction corrections for astronomical observations. We find that R(V) varies with extinction, consistent with dust grains growing by accretion in low-extinction regions and by coagulation in higher-extinction regions. Star-forming regions have high R(V) values, indicating either preferential destruction of small dust grains or additional supply of large dust grains in those regions.

物理学Physics

Circularly polarized electroluminescence from chiral supramolecular semiconductor thin films

手性超分子半导体薄膜的圆偏振电致发光

▲ 作者：RITUPARNO CHOWDHURY, MARCO D. PREUSS, HWAN-HEE CHO, JOSHUA J. P. THOMPSON, SAMARPITA SEN, TOMI K. BAIKIE, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.adt3011

▲摘要：

当前有机发光二极管（OLED）技术使用了分子主体中的发光分子。

研究组报道了手性有序超分子组装中的绿色圆偏振发光（CPL），在三氮杂蒽（TAT）系统中具有24%的不对称性。他们发现TAT组装成螺距为六个分子的螺旋结构，通过将角动量与价带和导带耦合，产生了所观察到的CPL。

在结构不匹配的“主体”材料中，TAT作为“客体”的共升华可实现薄膜的制造，其中掺杂剂和主体通过热触发纳米相分离来原位实现手性结晶，同时保持薄膜的完整性。这种OLED的外量子效率高达16%，电致发光不对称性≥10%。手性超结构的真空沉积为探索手性驱动的光学现象和输运现象提供了新的机会。

▲ Abstract：

Current organic light-emitting diode (OLED) technology uses light-emitting molecules in a molecular host. We report green circularly polarized luminescence (CPL) in a chirally ordered supramolecular assembly, with 24% dissymmetry in a triazatruxene (TAT) system. We found that TAT assembled into helices with a pitch of six molecules, associating angular momentum to the valence and conduction bands and obtaining the observed CPL. Cosublimation of TAT as the “guest” in a structurally mismatched “host” enabled fabrication of thin films in which chiral crystallization was achieved in situ by thermally triggered nanophase segregation of dopant and host while preserving film integrity. The OLEDs showed external quantum efficiencies of up to 16% and electroluminescence dissymmetries ≥10%. Vacuum deposition of chiral superstructures opens new opportunities to explore chiral-driven optical and transport phenomena.

Piezoelectricity in half-Heusler narrow-bandgap semiconductors

半赫斯勒窄带隙半导体中的压电性

▲ 作者：YI HUANG, FU LV, SHEN HAN, MENGZHAO CHEN, YUECHU WANG, QIANHUI LOU, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.ads9584

▲摘要：

压电性主要在非中心对称绝缘体或宽带隙半导体中观察到。

研究组报道了半赫斯勒（HH）窄带隙半导体TiNiSn、ZrNiSn和TiCoSb中观察到的压电（PE）效应。这些材料的剪切PE应变系数在ZrNiSn和TiCoSb中分别达到约38和33 pC/N，这是非中心对称非极性材料中的较高值。

研究组展示了一种基于TiCoSb的PE传感器，其具有很大的电压响应，能够为电容器充电。HHs中的PE效应在高达1173 K的温度下保持热稳定性，凸显了其在高温应用中的潜力。该观察结果表明，这些HH窄带隙半导体有望应用于先进多功能技术领域。

▲ Abstract：

Piezoelectricity is primarily observed in noncentrosymmetric insulators or wide bandgap semiconductors. We report the observation of the piezoelectric (PE) effect in half-Heusler (HH) narrow-bandgap semiconductors TiNiSn, ZrNiSn, and TiCoSb. These materials exhibit shear PE strain coefficients that reach ~38 and 33 picocoulombs per newton in ZrNiSn and TiCoSb, respectively, which are high values for noncentrosymmetric nonpolar materials. We demonstrated a TiCoSb-based PE sensor with a large voltage response and capable of charging a capacitor. The PE effect in HHs remains thermally stable up to 1173 kelvin, underscoring their potential for high-temperature applications. Our observations suggest that these HH narrow-bandgap semiconductors may find promising applications for advanced multifunctional technologies.

化学Chemistry

Excited-state configuration of nitroarenes enables oxidative cleavage of aromatics over alkenes

硝基芳烃的激发态构型实现芳烃优先于烯烃进行氧化裂解

▲ 作者：WESLEY J. OLIVIER, PIOTR B?YSZCZYK, ENRIQUE M. ARPA, KENSHIRO HITOSHIO, MIGUEL GOMEZ-MENDOZA, VíCTOR DE LA PE?A O’SHEA, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.ads3955

▲摘要：

芳烃的臭氧分解仍是有机化学领域的一个挑战。臭氧优先与烯烃而不是与芳烃反应，这意味着一旦初始芳烃发生裂解，脱芳烃产物本质上比起始物质更具反应性。因此，这个过程无法停止，导致完全氧化。解决这一挑战需要颠覆传统化学选择性的内在规则，即在反应性更强底物存在的情况下转化反应性较弱底物。

研究组证明这个概念可通过使用光激发硝基芳烃来实现。这种化学选择过程成功的关键是使用硝基芳烃，它优先激发到三重态π,π*态而不是n,π*态。激发态构型的这种转变提供了一个原本无法实现的其他路径，即在烯烃存在的情况下，氧化裂解转向芳烃。

▲ Abstract：

The ozonolytic deconstruction of aromatics remains a challenge in organic chemistry. Ozone preferentially reacts with alkenes over arenes, meaning that once the initial aromatic cleavage occurs, the dearomatized products are inherently more reactive than the starting materials. Consequently, the process cannot be halted, resulting in full oxidation. Addressing this challenge requires subverting intrinsic rules of chemoselectivity to transform a less reactive substrate in the presence of a more reactive one. We demonstrate that this concept can be achieved by using photoexcited nitroarenes. Crucial to the success of this chemoselective process is the use of a nitroarene that is preferentially excitable to a triplet π,π* state over the n,π* state. This switch in excited-state configuration provides an otherwise inaccessible manifold, in which oxidative cleavage is diverted toward aromatics in the presence of alkenes.

地球科学Earth Science

Geological resource production constrained by regional water availability

区域水资源可用性制约地质资源生产

▲ 作者：KAMRUL ISLAM, KEITARO MAENO, RYOSUKE YOKOI, DAMIEN GIURCO, SHIGEMI KAGAWA, SHINSUKE MURAKAMI, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.adk5318

▲摘要：

虽然全球经济需要开采地质资源，但生产对环境有重大影响，包括使用区域可用水。

研究组将区域水资源可用性作为限制因素，揭示了32种开采地质资源的全球生产能力。他们发现，目前的资源开采大大超过了区域水资源限制，特别是2010年的铜开采（当前产量的37%超过了可用的水资源容量）。将生产地点转移到水资源压力较小的地区将缓解目前超出水资源限制的情况；然而考虑到经济因素，这并不现实。

预计未来对地质资源的需求将需要大幅增加用水量。考虑水资源在地质资源生产中的限制对可持续发展至关重要。

▲ Abstract：

Although the global economy requires geological resource mining, production has substantial environmental impacts, including the use of regional available water. In this study, we shed light on the global production capacity of 32 mined geological resources, considering regional water availability as a constraint. We found that current resource mining greatly exceeds regional water constraints for several, notably copper (37% of current production exceeds available water capacity) in 2010. Changing the location of production to regions of lower water stress would alleviate current exceedances of water constraints; however, considering economic factors shows that this is not always feasible. Future demand for geological resources is expected to require a considerable increase in water consumption. Considering the constraints of water resources in geological resource production is crucial for sustainability.

Deep learning the flow law of Antarctic ice shelves

深度学习南极冰架的流动规律

▲ 作者：YONGJI WANG, CHING-YAO LAI, DAVID J. PRIOR AND CHARLIE COWEN-BREEN

▲链接：

https://www.science.org/doi/10.1126/science.adp3300

▲摘要：

南极冰架支撑着地面冰盖，减缓了全球海平面的上升。然而，冰的流动规律和粘度结构等基本力学性质仍存在争议。

在这项工作中，研究组结合遥感数据和物理知识的深度学习，对多个冰架进行了分析，发现压缩区的冰流动规律遵循粒度敏感的复合流变规律，而扩展区的冰则具有各向异性。

研究组构建了冰架范围的各向异性黏度图，捕捉了抑制裂谷传播的缝合带结构。在接地带附近推断的应力指数决定了接地线冰通量和稳定性，而推断的粘度图则为裂谷的预测提供了信息。两者对于预测南极冰盖未来的质量损失都是至关重要的。

▲ Abstract：

Antarctic ice shelves buttress the grounded ice sheet, mitigating global sea level rise. However, fundamental mechanical properties, such as the ice flow law and viscosity structure, remain under debate. In this work, by leveraging remote-sensing data and physics-informed deep learning, we provide evidence over several ice shelves that the flow law follows a grain size–sensitive composite rheology in the compression zone. In the extension zone, we found that ice exhibits anisotropic properties. We constructed ice shelf–wide anisotropic viscosity maps that capture the suture zones, which inhibit rift propagation. The inferred stress exponent near the grounding zone dictates the grounding-line ice flux and grounding line stability, whereas the inferred viscosity maps inform the prediction of rifts. Both are essential for predicting the future mass loss of the Antarctic Ice Sheet.