《科学》（20230331出版）一周论文导读
2023/4/2 20:07:10 科学网

     编译 | 未玖

     Science, 31 MAR 2023, VOL 379, ISSUE 6639

     《科学》，2023年3月31日，第379卷，6639期

    

     天文学Astronomy

     A cosmic stream of atomic carbon gas connected to a massive radio galaxy at redshift 3.8

     原子碳气体宇宙流在红移3.8时连接到巨射电星系

     ▲ 作者：BJORN H. C. EMONTS, MATTHEW D. LEHNERT, ILSANG YOON, NIR MANDELKER, MONTSERRAT VILLAR-MART?N, GEORGE K. MILEY, ET AL.

     ▲ 链接：

     https://www.science.org/doi/10.1126/science.abh2150

     ▲ 摘要：

     早期宇宙中星系的生长由星系周围和星系间气体的吸积所驱动。模拟预测，稳定的冷气体流会穿透星系的暗物质晕，并提供维持恒星形成所需的原材料。

     研究组报道了一股延伸100千秒差距的丝状气流，连接到巨射电星系4C 41.17。他们利用原子碳[C_I]线(一种中性原子或分子氢气的示踪剂)的³P₁到³P₀发射的亚毫米观测探测到该气流。

     该星系包含一个中央气体库，可为一场猛烈星爆提供燃料。研究结果表明，恒星形成的原材料可能存在于星系外的宇宙流中。

     ▲ Abstract：

     The growth of galaxies in the early Universe is driven by accretion of circum- and intergalactic gas. Simulations have predicted that steady streams of cold gas penetrate the dark matter halos of galaxies and provide the raw material necessary to sustain star formation. We report a filamentary stream of gas that extends for 100 kiloparsecs and connects to the massive radio galaxy 4C 41.17. We detected the stream using submillimeter observations of the ³P₁ to ³P₀ emission from the [C_I] line of atomic carbon, a tracer of neutral atomic or molecular hydrogen gas. The galaxy contains a central gas reservoir that is fueling a vigorous starburst. Our results show that the raw material for star formation can be present in cosmic streams outside galaxies.

     物理学Physics

     Moiré photonics and optoelectronics

     莫尔光子学和光电子学

     ▲ 作者：LUOJUN DU, MACIEJ R. MOLAS, ZHIHENG HUANG, GUANGYU ZHANG, FENG WANG AND ZHIPEI SUN

     ▲ 链接：

     https://www.science.org/doi/10.1126/science.adg0014

     ▲ 摘要：

     莫尔超晶格是一种人工量子材料，为探索全新的物理和器件结构提供了广泛可能性。

     在该文中，研究组重点介绍了新兴莫尔光子学和光电子学的最新进展，包括但不限于莫尔激子、三重子和极化激子；共振杂化激子；重构集体激励；强中-远红外光响应；太赫兹单光子探测；以及对称破缺光电子。

     研究组还讨论了该领域未来的机遇和研究方向，例如开发先进的技术来探测单个莫尔超晶胞中的新兴光子学和光电子学；探索新的铁电、磁和多铁莫尔系统；以及利用外部自由度来设计莫尔属性，以实现令人兴奋的物理学和潜在的技术创新。

     ▲ Abstract：

     Moiré superlattices, the artificial quantum materials, have provided a wide range of possibilities for the exploration of completely new physics and device architectures. In this Review, we focus on the recent progress on emerging moiré photonics and optoelectronics, including but not limited to moiré excitons, trions, and polaritons; resonantly hybridized excitons; reconstructed collective excitations; strong mid- and far-infrared photoresponses; terahertz single-photon detection; and symmetry-breaking optoelectronics. We also discuss the future opportunities and research directions in this field, such as developing advanced techniques to probe the emergent photonics and optoelectronics in an individual moiré supercell; exploring new ferroelectric, magnetic, and multiferroic moiré systems; and using external degrees of freedom to engineer moiré properties for exciting physics and potential technological innovations.

     材料科学Materials Science

     Fiber pumps for wearable fluidic systems

     用于可穿戴流体系统的纤维泵

     ▲ 作者：MICHAEL SMITH, VITO CACUCCIOLO AND HERBERT SHEA

     ▲ 链接：

     https://www.science.org/doi/10.1126/science.ade8654

     ▲ 摘要：

     将加压流体回路集成到纺织品中，能够以方便的可穿戴形状实现肌肉支撑、体温调节和触觉反馈。然而，传统的刚性泵及其相关噪音和振动，不适用于大多数可穿戴设备。

     研究组报道了可拉伸纤维形式的流体泵。这使得压力源可直接集成到纺织品中，从而实现无约束的可穿戴流体。该流体泵由嵌入在薄弹性体管壁内的连续螺旋电极组成，通过电荷注入电流体动力学无声地产生压力。

     每米纤维产生100kPa的压力，流速可接近55mL/min，这相当于15W/kg的功率密度。通过可穿戴触觉反馈、机械活性织物和温度调节纺织品的演示，研究组证明该策略有望实现设计自由。

     ▲ Abstract：

     Incorporating pressurized fluidic circuits into textiles can enable muscular support, thermoregulation, and haptic feedback in a convenient wearable form factor. However, conventional rigid pumps, with their associated noise and vibration, are unsuitable for most wearables. We report fluidic pumps in the form of stretchable fibers. This allows pressure sources to be integrated directly into textiles, enabling untethered wearable fluidics. Our pumps consist of continuous helical electrodes embedded within the walls of thin elastomer tubing and generate pressure silently through charge-injection electrohydrodynamics. Each meter of fiber generates 100 kilopascals of pressure, and flow rates approaching 55 milliliters per minute are possible, which is equivalent to a power density of 15 watts per kilogram. The benefits in design freedom are considerable, which we illustrate with demonstrations of wearable haptics, mechanically active fabrics, and thermoregulatory textiles.

     化学Chemistry

     Oxidative rearrangement of 1,1-disubstituted alkenes to ketones

     1,1-二取代烯烃氧化重排生成酮

     ▲ 作者：QIANG FENG, QIAN WANG AND JIEPING ZHU

     ▲ 链接：

     https://www.science.org/doi/10.1126/science.adg3182

     ▲ 摘要：

     Wacker工艺广泛应用于将单取代烯烃转化为相应的甲基酮，人们认为其通过涉及β-氢化物消除步骤的Pd^II/Pd⁰催化循环进行。但这种机理不适用于由1,1-二取代烯烃合成酮。目前基于Pd^II中间体的半频哪醇重排的方法仅限于高应变亚甲基环丁烷衍生物的扩环反应。

     研究组通过设计一个Pd^II/Pd^IV催化循环，将1,2-烷基/Pd^IV的dyotropic重排作为关键步骤，解决了这一合成难题。该反应与广泛的官能团相容，适用于直链烯烃和亚甲基环烷烃，包括大环化合物。

     研究组还观察到，区域选择性有利于更多取代碳的迁移，β-羧基也有很强的定向作用。

     ▲ Abstract：

     The Wacker process, which is widely used to convert monosubstituted alkenes into the corresponding methyl ketones, is thought to proceed through a Pd^II/Pd⁰ catalytic cycle involving a β-hydride elimination step. This mechanistic scenario is inapplicable to the synthesis of ketones from the 1,1-disubstituted alkenes. Current approaches based on semi-pinacol rearrangement of Pd^II intermediates are limited to the ring expansion of highly strained methylene cyclobutane derivatives. Herein, we report a solution to this synthetic challenge by designing a Pd^II/Pd^IV catalytic cycle incorporating a 1,2-alkyl/Pd^IV dyotropic rearrangement as a key step. This reaction, compatible with a broad range of functional groups, is applicable to both linear olefins and methylene cycloalkanes, including macrocycles. Regioselectivity favors the migration of the more substituted carbon, and a strong directing effect of the β-carboxyl group was also observed.

     地球科学Earth Science

     Soil respiration–drivenCO₂ pulses dominate Australia’s flux variability

     土壤呼吸驱动的CO₂脉冲主导了澳大利亚的通量变化

     ▲作者：EVA-MARIE METZ, SANAM N. VARDAG, SOURISH BASU, MARTIN JUNG, BERNHARD AHRENS, TAREK EL-MADANY, ET AL.

     ▲ 链接：

     https://www.science.org/doi/10.1126/science.add7833

     ▲ 摘要：

     澳大利亚大陆对全球陆地二氧化碳(CO₂)汇的逐年变化贡献很大。然而，偏远地区现场观测资料的缺乏，阻碍了人们对迫使CO₂通量变化过程的解读。

     在这项研究中，通过检查2009-2018年间卫星对大气CO₂的测量结果，研究组发现澳大利亚大陆上空出现了周期性的旱季末CO₂脉冲。这些脉冲在很大程度上主导了澳大利亚CO₂平衡的逐年变化。

     与以前自上而下的反演和自下而上的估计相比，CO₂脉冲造成的季节变化要大两到三倍。在澳大利亚的半干旱地区，这种脉冲发生在降雨开始后不久，光合作用吸收之前，由增强的土壤呼吸所驱动。

     该研究所提出的土壤再润湿过程的大陆尺度相关性对人们理解和建模全球气候-碳循环反馈具有重要意义。

     ▲ Abstract：

     The Australian continent contributes substantially to the year-to-year variability of the global terrestrial carbon dioxide (CO₂) sink. However, the scarcity of in situ observations in remote areas prevents the deciphering of processes that force the CO₂ flux variability. In this study, by examining atmospheric CO₂ measurements from satellites in the period 2009–2018, we find recurrent end-of-dry-season CO₂pulses over the Australian continent. These pulses largely control the year-to-year variability of Australia’s CO₂ balance. They cause two to three times larger seasonal variations compared with previous top-down inversions and bottom-up estimates. The pulses occur shortly after the onset of rainfall and are driven by enhanced soil respiration preceding photosynthetic uptake in Australia’s semiarid regions. The suggested continental-scale relevance of soil-rewetting processes has substantial implications for our understanding and modeling of global climate–carbon cycle feedbacks.

     考古学Archaeology

     Early dispersal of domestic horses into the Great Plains and northern Rockies

     驯养马在美国大平原和落基山脉北部的早期扩散

     ▲ 作者：WILLIAM TIMOTHY TREAL TAYLOR, PABLO LIBRADO, MILA HUNSKA TA?UNKE ICU, CARLTON SHIELD CHIEF GOVER, JIMMY ARTERBERRY, ANPETU LUTA WI?, ET AL.

     ▲ 链接：

     https://www.science.org/doi/10.1126/science.adc9691

     ▲ 摘要：

     马对于横跨美国西南部和大平原的诸多土著文明极为重要。然而，马何时以及如何首次融入土著生活仍存在争议，现存模型主要来源于殖民地记录。

     研究组对一组历史考古发现的马遗骸进行了跨学科研究，整合了基因组、同位素、放射性碳和古病理学证据。考古马遗骸和现代北美马显示出强烈的伊比利亚遗传亲缘性，表明其后期从英国传入，但没有维京血统。

     17世纪上半叶，马很可能通过土著交流网络，从南部迅速扩散到落基山脉北部和中部平原。在18世纪欧洲殖民者到来之前，马已经深深地融入了土著社会，这反映在牧群管理、仪式实践和文化上。

     ▲ Abstract：

     The horse is central to many Indigenous cultures across the American Southwest and the Great Plains. However, when and how horses were first integrated into Indigenous lifeways remain contentious, with extant models derived largely from colonial records. We conducted an interdisciplinary study of an assemblage of historic archaeological horse remains, integrating genomic, isotopic, radiocarbon, and paleopathological evidence. Archaeological and modern North American horses show strong Iberian genetic affinities, with later influx from British sources, but no Viking proximity. Horses rapidly spread from the south into the northern Rockies and central plains by the first half of the 17th century CE, likely through Indigenous exchange networks. They were deeply integrated into Indigenous societies before the arrival of 18th-century European observers, as reflected in herd management, ceremonial practices, and culture.

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