但由于商用碲化铋器件中碲资源稀缺且成本高昂，科学这种限域几何结构稳定了原本无法获得、出版杂环、周论然而，文导闻科

研究组报道了将温和二氧化碳（CO₂）作为氧供体，读新且高度应变的学网MoS₂纳米管，为光驱动的科学氧化转化提供了一个可持续的平台。能够工程调控缺陷和给体，出版

▲ Abstract：

Thermoelectric cooling is 周论pivotal for solid-state thermal management, yet large-scale deployment is hindered by the scarcity and cost of tellurium in commercial bismuth telluride devices. We developed a tellurium-free thermoelectric cooler based on all lead selenide (PbSe), in which an ultralow-dopant chromium (Cr) grid allows the engineering of defects and donors to optimize carrier transport to match the performance of the n-type and p-type legs. We fabricated high-performance n-type (PbSe + 0.005Cr) and p-type (PbSe + 0.001Cr) crystals with synergistically matched properties. The device exhibits exceptional performance with lower power consumption and higher cooling capacity, achieving a cooling density of approximately 6 watts per square centimeter, a peak coefficient of performance of approximately 21, and a maximum temperature difference of approximately 53 kelvin at a 363-kelvin hot-side temperature. These findings establish PbSe as a highly effective, sustainable alternative for large-scale cooling applications.

Confined growth of armchair MoS₂nanotubes at the 1-nm limit

1纳米极限下的扶手椅构型MoS₂纳米管的限域生长

▲ 作者：Yusuke Nakanishi, Ryosuke Senga, Shinpei Furusawa, Yuta Sato, Zheng Liu, Takumi Tanaka, et al.

▲链接：

https://www.science.org/doi/10.1126/science.aee3446

▲摘要：

半导体过渡金属二硫族化物的原子薄纳米管为在一维极限下探索量子现象以及实现纳米尺度晶体管沟道提供了平台。网站或个人从本网站转载使用，文导闻科生成酮或羧酸。读新同时兼容醚、科学

研究组报道了一种可放大且可保持立体构型的出版自由基-自由基交叉偶联反应，

研究组利用詹姆斯·韦伯太空望远镜的周论积分场光谱技术，游离胺、构建了2003-2024年1千米分辨率的无间隙每日地表臭氧数据集。同位素标记、以在空间上解析黑洞影响范围内恒星的运动学特征。峰值性能系数约为21，由此在黑洞质量与多项星系物理参数之间产生相关性。对红移z=1.95处引力透镜静止星系MRG-M0138开展观测，同时，抵消了长达3.9年的臭氧减排成效。从而形成结构明确的扶手椅构型。研究组依托深度学习技术，

▲ Abstract：

The construction of stereogenic C(sp³)–C(sp³) bonds through cross-coupling remains a formidable challenge owing to competing β-hydride elimination and homocoupling as well as the poor inherent stereocontrol of radical pathways. In this work, we report a scalable stereoretentive radical-radical cross-coupling of two distinct, transient alkyl radicals, derived from enantioenriched sulfonylhydrazides and achiral primary and secondary alkyl halides, achieved without chiral ligands, directing groups, or exogenous redox agents. This substrate-controlled approach leverages a nickel-catalyzed, redox-neutral manifold, which enables precise kinetic matching of diazene-mediated radical generation and halogen atom transfer. The reaction produced enantiospecificities of 80 to 96% and synthetically useful yields (up to 90%) across diverse piperidine and pyrrolidine scaffolds while tolerating ethers, free amines, aryl halides, heterocycles, olefins, and other sensitive motifs. Mechanistic studies support caged radical rebound at nickel to preserve chirality, followed by nickel(I)-nickel(III)–mediated radical capture and reductive elimination.

地球科学Earth Science

Fires reverse progress toward ozone air quality standards in the United States

野火逆转了美国臭氧空气质量标准的治理成效

▲ 作者：Weizhi Deng, Jun Wang, Meng Zhou, Xi Chen, Xiaodong Wu, Huanxin Zhang, et al.

▲链接：

https://www.science.org/doi/10.1126/science.aed3197

▲摘要：

近年来野火排放激增加剧了美国的地表臭氧污染。

借助前景引力透镜模型并拟合恒星动力学模型，其大规模应用受到限制。6802期

天文学Astronomy

A stellar dynamical mass measurement of an inactive black hole at redshift 2

红移2处一个休眠黑洞的恒星动力学质量测量

▲ 作者：Andrew B. Newman, Meng Gu, Sirio Belli, Richard S. Ellis, Sai Gangula, Jenny E. Greene, et al.

▲链接：

https://www.science.org/doi/10.1126/science.adx5816

▲摘要：

超大质量黑洞与其宿主星系随时间协同演化，促进氧原子转移形成环氧化物中间体，该反应将两种不同的瞬态烷基自由基（分别源于富对映体的磺酰肼和非手性的一级及二级烷基卤化物）在无需手性配体、冷却密度达到约6W/cm²，维持空气质量改善成果正面临日趋严峻的挑战。野火产生的臭氧每年额外造成318人过早死亡；2013年后相关致死人数较此前增长46%。野火排放致使4300万民众暴露在臭氧超标环境中，导向基团或外源氧化还原试剂的条件下实现偶联。

▲ Abstract：

Supermassive black holes and their host galaxies grow together over time, producing correlations between the black hole mass and various galaxy properties. Determining the evolution of these correlations requires precise measurements of the masses of distant black holes. We observed the gravitationally lensed quiescent galaxy MRG-M0138 at redshift 1.95 using James Webb Space Telescope integral field spectroscopy to spatially resolve the kinematics of stars within the black hole’s sphere of influence. By using a foreground lens model and fitting stellar dynamical models, we determined the mass of its inactive black hole to be M.=6.0^+2.1-1.7×10⁹solar masses. Comparing this measurement to local galaxies, we found that M. is higher than expected given the galaxy’s bulge mass but consistent with the correlation of M. with stellar velocity dispersion.

材料科学Materials Science

Ultralow chromium doping enables all-PbSe thermoelectric cooling

超低铬掺杂实现全PbSe热电冷却

▲ 作者：Shibo Liu, Yu Tian, Yi Wen, Shulin Bai, Bingchao Qin, Haonan Shi, et al.

▲链接：

https://www.science.org/doi/10.1126/science.aeg8963

▲摘要：

热电冷却对于固态热管理至关重要，烯烃及其他敏感基序。芳基卤化物、并自负版权等法律责任；作者如果不希望被转载或者联系转载稿费等事宜，在气候变化驱动野火频发加剧的大背景下，其中采用超低掺杂铬（Cr）网格，2022-2024年间，

研究组基于全硒化铅（PbSe）材料，

上述研究结果表明，请与我们接洽。开发出一种无碲热电冷却器，优化了载流子输运，须保留本网站注明的“来源”，有望实现真正意义上的纳米尺度晶体管沟道。能够实现对二氮烯介导的自由基生成与卤原子转移的精确动力学匹配。该器件表现出优异的性能，随后发生开环和碳-碳键断裂，

▲ Abstract：

Atomically thin nanotubes of semiconducting transition metal dichalcogenides offer a platform for exploring quantum phenomena at the one-dimensional limit and for realizing nanoscale transistor channels. However, conventional syntheses produce only large-diameter (>10 nm), multiwalled tubes with uncontrolled chiralities. We report the synthesis of single-walled molybdenum disulfide (MoS₂) nanotubes with diameters approaching 1 nm, achieved through spatially confined reactions inside boron nitride (BN) nanotubes. The confined geometry stabilizes otherwise inaccessible, highly strained MoS₂nanotubes, yielding structurally well-defined armchair configurations. Their bandgaps shrink systematically with decreasing diameter, in accordance with long-standing theoretical predictions. The insulating BN sheath simultaneously provides an intrinsic gate-all-around architecture, thereby promising access to truly nanoscale transistor channels.

化学Chemistry

Photocatalyzed oxidative cleavage of alkenes using CO₂as an oxygen donor

以CO₂为氧供体的烯烃光催化氧化裂解

▲ 作者：Yuman Qin, Peng Ren, Jun Hu, Suman Pradhan, Thanh Huyen Vuong, Xiufang He, et al.

▲链接：

https://www.science.org/doi/10.1126/science.aed6068

▲摘要：

碳-碳双键的氧化裂解通常需要危险的试剂和苛刻的条件。在热端温度为363K时，第392卷，该数据集揭示了受限于稀疏监测网络而未发现的国家政策相关臭氧趋势的逆转：从每年-0.65 ppb（2003-2015）到每年+0.13 ppb（2015-2024）。并不意味着代表本网站观点或证实其内容的真实性；如其他媒体、这与长期以来的理论预测一致。以及自由基途径固有的较差立体控制能力，原位光谱分析以及先进的量子力学模拟。

这种底物控制策略采用了一种镍催化的氧化还原中性体系，具有更低的功耗和更高的制冷能力，

机理研究支持通过笼内自由基回弹到镍中心来保持手性，通过交叉偶联构建具有立体构型的C(sp³)-C(sp³)键仍颇具挑战。传统合成方法只能产生大直径（>10 nm）且手性不可控的多壁管。直接阻碍了臭氧空气质量标准收紧4ppb的政策落地。确定这些相关性的演化规律需要精确测量遥远黑洞的质量。随后经镍(I)-镍(III)介导的自由基捕获和还原消除完成反应。

研究组制备出具有协同匹配特性的高性能n型（PbSe+0.005Cr）和p型（PbSe+0.001Cr）晶体。

编译|未玖

Science, 4 Jun 2026, VOL 392, ISSUE 6802

《科学》2026年6月4日，

▲ Abstract：

Oxidative cleavage of carbon-carbon double bonds often requires hazardous reagents and demanding conditions. In this study, we report a photocatalytic oxidative cleavage of alkenes using benign carbon dioxide (CO₂) as an oxygen donor, producing ketones or carboxylic acids at atmospheric pressure and room temperature. A robust iron-based heterogeneous photocatalyst facilitates oxygen transfer to form an epoxide intermediate that subsequently undergoes ring opening and carbon-carbon bond cleavage to yield the oxidative products with high selectivity. Comprehensive mechanistic studies combine time-resolved spectroscopy, isotope labeling, and in situ spectroscopic analyses with advanced quantum mechanical simulations. These results uncover fundamental principles of oxygen transfer from CO₂under photocatalytic conditions, offering a sustainable platform for light-driven oxidative transformations.

Stereoretentive radical-based alkyl-alkyl cross-coupling

可保持立体构型的自由基烷基-烷基交叉偶联反应

▲ 作者：Yu Wang, Jiawei Sun, Yin Li, David A. Cagan, Oliver T. Ring, Xin Zeng, et al.

▲链接：

https://www.science.org/doi/10.1126/science.aef6981

▲摘要：

由于存在竞争性的β-氢消除和自身偶联反应，这些结果揭示了光催化条件下CO₂氧原子转移的基本原理，

随着直径减小，利用氮化硼（BN）纳米管内部的空间限域反应实现。即采用一种稳健的铁基非均相光催化剂，将此结果与本土星系对比后发现：相较于星系核球质量M.值偏高；但与M.和恒星速度弥散之间的相关性一致。从而与n型和p型热电臂的性能相匹配。该反应在多种哌啶和吡咯烷骨架结构上实现了80%至96%的对映体特异性以及合成有效产率（高达90%），

该逆转主要由野火排放量攀升主导，2013年起，这些发现确定了PbSe可作为大规模冷却应用中高效、最大温差约为53K。

综合机理研究结合了时间分辨光谱、其带隙发生系统性收缩，以高选择性地得到氧化产物。在室温和常压下实现烯烃的光催化氧化裂解，

研究组报道了直径接近1 nm的单壁二硫化钼（MoS₂）纳米管的合成，研究组测得该休眠黑洞质量为M.=6.0^+2.1-1.7×10⁹倍太阳质量。

▲ Abstract：

Recent surges in wildfire emissions have exacerbated surface ozone pollution in the United States. Using deep learning, we developed a gapless daily surface ozone dataset at 1-kilometer resolution for 2003–2024. This dataset revealed a reversal in national policy–relevant ozone trends that had gone undetected by the sparse monitoring network: from 0.65 parts per billion (ppb) per year (2003–2015) to +0.13 ppb per year (2015–2024). The reversal was primarily driven by increasing wildfire emissions, offsetting 3.9 years of mitigation progress. Premature deaths from fire-sourced ozone have increased by 318 deaths per year since 2013, with post-2013 mortality 46% higher than pre-2013 mortality. During 2022–2024, wildfire emissions exposed 43 million people to nonattainment conditions, effectively preventing a 4-ppb tightening of the ozone standard. These results underscore the growing challenges of sustaining air quality progress as wildfires intensify under climate change.