編譯|未玖
Nature, 21 August 2025, Volume 644 Issue 8077
《自然》，2025年8月21日，第644卷，8077期
天文學(xué)Astronomy
Extremely stripped supernova reveals a silicon and sulfur formation site
極度剝離的超新星揭示了硅和硫的形成位置
▲ 作者：Steve Schulze, Avishay Gal-Yam et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09375-3
▲摘要：
恒星最初由氫和氦的聚變提供能量。這些灰燼在一系列階段中充當(dāng)燃料，將大質(zhì)量恒星轉(zhuǎn)變成殼層結(jié)構(gòu)。這些殼層結(jié)構(gòu)由外部原生氫和內(nèi)部連續(xù)較重的成分組成，預(yù)計(jì)主要由He、C/O、O/Ne/Mg和O/Si/S組成。硅和硫融合成鐵，導(dǎo)致核心坍塌，要么發(fā)生超新星爆炸，要么形成黑洞。
剝離恒星的外層氫層被移除后，內(nèi)部富氦層甚至其下方的C/O層暴露出來，為這種殼層結(jié)構(gòu)及其所反映的宇宙元素產(chǎn)生機(jī)制提供了證據(jù)。由剝離恒星嵌入星周物質(zhì)（CSM）殼中產(chǎn)生的超新星類型證實(shí)了這一情況。然而，目前尚無直接證據(jù)表明，大多數(shù)內(nèi)殼負(fù)責(zé)產(chǎn)生比氧重的元素。
研究組報(bào)道了超新星（SN 2021yfj的發(fā)現(xiàn)，由一顆恒星剝離至其富O/Si/S層而產(chǎn)生。他們直接觀察到一層厚厚的富Si/S殼層，在超新星爆炸前不久由前身恒星排出。從理論上講，揭示這樣的恒星內(nèi)層頗具挑戰(zhàn)性，可能需要一種很少觀測(cè)到的質(zhì)量損失機(jī)制。這一罕見的超新星事件揭示了恒星演化的高級(jí)階段，形成了比任何已知大質(zhì)量恒星表面檢測(cè)到的更重的元素，包括硅、硫和氬。
▲ Abstract：
Stars are initially powered by the fusion of hydrogen to helium. These ashes serve as fuel in a series of stages, transforming massive stars into a structure of shells. These are composed of natal hydrogen on the outside and consecutively heavier compositions inside, predicted to be dominated by He, C/O, O/Ne/Mg and O/Si/S. Silicon and sulfur are fused into iron, leading to the collapse of the core and either a supernova explosion or the formation of a black hole. Stripped stars, in which the outer hydrogen layer has been removed and the internal He-rich or even the C/O layer below it is exposed, provide evidence for this shell structure and the cosmic element production mechanism it reflects. The supernova types that arise from stripped stars embedded in shells of circumstellar material (CSM) confirm this scenario. However, direct evidence for the most interior shells, which are responsible for producing elements heavier than oxygen, is lacking. Here we report the discovery of the supernova (SN) 2021yfj resulting from a star stripped to its O/Si/S-rich layer. We directly observe a thick, massive Si/S-rich shell, expelled by the progenitor shortly before the supernova explosion. Exposing such an inner stellar layer is theoretically challenging and probably requires a rarely observed mass-loss mechanism. This rare supernova event reveals advanced stages of stellar evolution, forming heavier elements, including silicon, sulfur and argon, than those detected on the surface of any known class of massive stars.
材料科學(xué)Materials Science
Electrochemical loading enhances deuterium fusion rates in a metal target
電化學(xué)加載提高了金屬靶中的氘聚變速率
▲ 作者：Kuo-Yi Chen, Jannis Maiwald et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09042-7
▲摘要：
能源應(yīng)用的核聚變研究旨在創(chuàng)造條件，釋放比觸發(fā)聚變過程所需的更多能量。為了產(chǎn)生有意義的能量，氘等燃料需要在空間上受到限制，以增加粒子的碰撞概率。因此，研究組著手探討用氘燃料電化學(xué)加載金屬晶格是否會(huì)增加核聚變事件的概率。
他們報(bào)告了一個(gè)臺(tái)式聚變反應(yīng)堆，實(shí)現(xiàn)了用氘離子轟擊鈀金屬靶。這些氘離子在鈀金屬中發(fā)生氘-氘聚變反應(yīng)。研究組發(fā)現(xiàn)，將氘原位電化學(xué)加載到鈀靶中導(dǎo)致氘-氘聚變速率提高了15（2）%。該實(shí)驗(yàn)展示了金屬靶在電子伏特能級(jí)上的電化學(xué)加載如何影響兆電子伏特能級(jí)上的核反應(yīng)。
▲ Abstract：
Nuclear fusion research for energy applications aims to create conditions that release more energy than required to initiate the fusion process. To generate meaningful amounts of energy, fuels such as deuterium need to be spatially confined to increase the collision probability of particles. We therefore set out to investigate whether electrochemically loading a metal lattice with deuterium fuel could increase the probability of nuclear fusion events. Here we report a benchtop fusion reactor that enabled us to bombard a palladium metal target with deuterium ions. These deuterium ions undergo deuterium–deuterium fusion reactions within the palladium metal. We showed that the in situ electrochemical loading of deuterium into the palladium target resulted in a 15(2)% increase in deuterium–deuterium fusion rates. This experiment shows how the electrochemical loading of a metal target at the electronvolt energy scale can affect nuclear reactions at the megaelectronvolt energy scale.
Delocalized electrolyte design enables 600 Wh kg?1 lithium metal pouch cells
離域電解液設(shè)計(jì)實(shí)現(xiàn)600 Wh kg?1 鋰金屬軟包電池
▲ 作者：He Huang, Yitao Hu et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09382-4
▲摘要：
高能鋰金屬電池（LMBs）的發(fā)展對(duì)于下一代儲(chǔ)能和電動(dòng)汽車技術(shù)的進(jìn)步至關(guān)重要。然而，LMB的實(shí)際應(yīng)用受到當(dāng)前依賴于主要溶劑化結(jié)構(gòu)的電解液設(shè)計(jì)的限制，阻礙了性能優(yōu)化的變革式進(jìn)展。
研究組通過一種離域電解液設(shè)計(jì)來解決這一限制，促進(jìn)了更無序的溶劑化微環(huán)境，從而減輕了動(dòng)力學(xué)障礙并穩(wěn)定了界面相。所得到的離域電解液在5.5 Ah、貧電解液設(shè)計(jì)的LiNi0.9Co0.05Mn0.05O2(Ni90) || 鋰軟包電池中能量密度高達(dá)604.2 Wh kg-1，可穩(wěn)定循環(huán)100次；在5.2 Ah、超貧電解液設(shè)計(jì)（0.9 g Ah-1）的Ni90||鋰袋電池中可穩(wěn)定循環(huán)90次。
此外，70-104 V NCM811||鋰電池組（3904 Wh）具有480.9 Wh kg?1的高能量密度和超過25次的穩(wěn)定循環(huán)。這些結(jié)果表明，在電解液設(shè)計(jì)中需要克服對(duì)主要溶劑化結(jié)構(gòu)的固有依賴，以實(shí)現(xiàn)高能Battery600和可擴(kuò)展的Pack480目標(biāo)。
▲ Abstract：
The development of high-energy lithium metal batteries (LMBs) is essential for advances in next-generation energy storage and electric vehicle technologies. Nevertheless, the practical applications of LMBs are constrained by current electrolyte designs that inherently rely on dominant solvation structures, preventing transformative progress in performance optimization. Here, we address this limitation through a delocalized electrolyte design that fosters a more disordered solvation microenvironment, thereby mitigating dynamic barriers and stabilizing interphases. The resulting delocalized electrolyte delivers notable energy densities of 604.2?Wh?kg?1 in a 5.5-Ah LiNi0.9Co0.05Mn0.05O2(Ni90)||Li pouch cell with a lean electrolyte design (1.0?g?Ah?1) and 618.2?Wh?kg?1 in a 5.2-Ah Ni90||Li pouch cell with an ultralean electrolyte design (0.9?g?Ah?1), maintaining significant cycle stability over 100 and 90 cycles, respectively. In addition, the 70–104?V NCM811||Li battery pack (3,904?Wh) exhibits a high energy density of 480.9?Wh?kg?1 and stable cycling over 25 cycles. These results demonstrate the need to circumvent inherent reliance on dominant solvation structures in electrolyte design to achieve the high-energy Battery600 and scalable Pack480 targets.
化學(xué)Chemistry
Acidic oxygen reduction by single-atom Fe catalysts on curved supports
彎曲載體上單原子鐵催化劑的酸性氧還原
▲ 作者：Yasong Zhao, Jiawei Wan et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09364-6
▲摘要：
為高性價(jià)比的質(zhì)子交換膜燃料電池開發(fā)高活性、耐用的電催化劑頗具挑戰(zhàn)。Fe/N-C催化劑是鉑族金屬催化劑中最有前景的替代品之一，但由于氧化反應(yīng)中間體的強(qiáng)吸附和Fenton反應(yīng)引起的Fe物種脫金屬，其活性和耐久性仍未滿足性能標(biāo)準(zhǔn)。
研究組設(shè)計(jì)并開發(fā)了一種新型的Fe/N-C催化劑，由分散在二維碳層上的多個(gè)納米突起組成，單個(gè)鐵原子位點(diǎn)主要嵌入在納米突起的內(nèi)曲面上。納米突起的石墨化外碳層不僅能有效削弱氧化反應(yīng)中間體的結(jié)合強(qiáng)度，還能降低羥基自由基的生成速率。
結(jié)果表明，F(xiàn)e/N-C催化劑提供了一種性能最佳的無鉑族金屬質(zhì)子交換膜燃料電池，在1.0 bar H2-空氣下實(shí)現(xiàn)了0.75 W cm-2的創(chuàng)紀(jì)錄高功率密度，在連續(xù)運(yùn)行超過300小時(shí)后，活性保持率為86%。
▲ Abstract：
Developing highly active and durable electrocatalysts for cost-effective proton-exchange membrane fuel cells is challenging. Fe/N–C catalysts are among the most promising alternatives to the platinum group metal catalysts, but their activity and durability still cannot meet the performance criteria due to the strong adsorption of oxygenated reaction intermediates and the demetallization of Fe species caused by the Fenton reaction. Here we design and develop a new type of Fe/N–C catalyst that is composed of numerous nanoprotrusions dispersed on two-dimensional carbon layers with single Fe-atom sites primarily embedded within the inner curved surface of the nanoprotrusions. The graphitized outer carbon layer of the nanoprotrusions can not only effectively weaken the binding strength of the oxygenated reaction intermediates, but also reduce the hydroxyl radical production rate. As a result, the Fe/N–C catalyst delivers one of the best-performing platinum group metal-free proton-exchange membrane fuel cell performances, achieving a record high power density of 0.75?W?cm?2under 1.0?bar H2–air with 86% activity retention after more than 300?hours of continuous operation.
地球科學(xué)Earth Science
Tropical response to ocean circulation slowdown raises future drought risk
熱帶對(duì)海洋環(huán)流減緩的響應(yīng)增加了未來的干旱風(fēng)險(xiǎn)
▲ 作者：Pedro N. DiNezio, Timothy M. Shanahan et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09319-x
▲摘要：
全球變暖下的熱帶降雨預(yù)測(cè)仍然高度不確定，主要是因?yàn)闅夂驅(qū)Υ笪餮蠼?jīng)向翻轉(zhuǎn)環(huán)流（AMOC）可能減弱的響應(yīng)不明確。盡管AMOC的減緩可以大幅改變熱帶降雨模式，但人們對(duì)高緯度變化與熱帶水文氣候之間的物理機(jī)制知之甚少。
研究組證明了AMOC的減緩?fù)ㄟ^高緯度冷卻向熱帶北大西洋的傳播，驅(qū)動(dòng)了熱帶降雨的廣泛變化。他們利用氣候模型模擬和Heinrich Stadial 1（HS1）的古氣候記錄（AMOC明顯減弱的過去時(shí)期）確定并驗(yàn)證了這一機(jī)制。
在模型中，盛行東風(fēng)和西風(fēng)通過熱帶和亞熱帶北大西洋上空的冷空氣輸送，將氣候信號(hào)傳遞到太平洋和印度洋。海氣相互作用將這種響應(yīng)傳遞到太平洋和印度洋，改變了遠(yuǎn)至印度尼西亞、熱帶安第斯山脈和澳大利亞北部的降雨模式。
在全球變暖情景下出現(xiàn)了類似的遙相關(guān)，產(chǎn)生了一致的多模型熱帶水文氣候變化模式。這些經(jīng)過古氣候驗(yàn)證的預(yù)測(cè)表明，中美洲、亞馬遜和西非地區(qū)普遍干旱，突顯出脆弱的人類和生態(tài)系統(tǒng)面臨嚴(yán)重干旱的風(fēng)險(xiǎn)增加。
▲ Abstract：
Projections of tropical rainfall under global warming remain highly uncertain, largely because of an unclear climate response to a potential weakening of the Atlantic meridional overturning circulation (AMOC). Although an AMOC slowdown can substantially alter tropical rainfall patterns, the physical mechanisms linking high-latitude changes to tropical hydroclimate are poorly understood. Here we demonstrate that an AMOC slowdown drives widespread shifts in tropical rainfall through the propagation of high-latitude cooling into the tropical North Atlantic. We identify and validate this mechanism using climate model simulations and palaeoclimate records from Heinrich Stadial 1 (HS1)—a past period marked by pronounced AMOC weakening. In models, prevailing easterly and westerly winds communicate the climate signal to the Pacific Ocean and Indian Ocean through the transport of cold air generated over the tropical and subtropical North Atlantic. Air–sea interactions transmit the response across the Pacific Ocean and Indian Ocean, altering rainfall patterns as far as Indonesia, the tropical Andes and northern Australia. A similar teleconnection emerges under global warming scenarios, producing a consistent multi-model pattern of tropical hydroclimatic change. These palaeo-validated projections show widespread drying across Mesoamerica, the Amazon and West Africa, highlighting an elevated risk of severe drought for vulnerable human and ecological systems.
Human emissions drive recent trends in North Pacific climate variations
人為排放驅(qū)動(dòng)了北太平洋氣候變化的最近趨勢(shì)
▲ 作者：Jeremy M. Klavans, Pedro N. DiNezio et al.
▲鏈接：
https://www.nature.com/articles/s41586-025-09368-2
▲摘要：
太平洋年代際振蕩（PDO）是驅(qū)動(dòng)北太平洋及周邊大陸變化的主要?dú)夂蜃兟誓Ｊ剑F(xiàn)在被認(rèn)為是由氣候系統(tǒng)內(nèi)部過程產(chǎn)生的。根據(jù)這一范式，PDO的特征性不規(guī)則振蕩源于北太平洋和熱帶太平洋海-氣相互作用的一系列機(jī)制。
最近海-氣耦合系統(tǒng)的變化（如2015年的厄爾尼諾）本應(yīng)已將PDO轉(zhuǎn)變?yōu)檎辔弧Ｈ欢?0多年來，PDO一直處于持續(xù)下降的趨勢(shì)，使附近地區(qū)受到一系列穩(wěn)定的氣候影響。
研究組表明，20世紀(jì)PDO指數(shù)的主要多年代際變化，包括持續(xù)數(shù)十年的負(fù)趨勢(shì)，主要是由人為排放的氣溶膠和溫室氣體驅(qū)動(dòng)的，而非內(nèi)部過程。這種人為影響以前未被發(fā)現(xiàn)，因?yàn)楫?dāng)前一代氣候模型系統(tǒng)地低估了強(qiáng)迫氣候變率的幅度。
一種新的歸因技術(shù)在統(tǒng)計(jì)學(xué)上糾正了這一錯(cuò)誤，通過外部強(qiáng)迫的PDO變化，表明觀測(cè)到的PDO影響（包括美國(guó)西部持續(xù)數(shù)十年的干旱）可在很大程度上歸因于人類活動(dòng)。這些結(jié)果表明，研究組需要重新思考區(qū)域氣候多年代際變化的歸因和預(yù)測(cè)。
▲ Abstract：
The Pacific decadal oscillation (PDO)—the leading pattern of climate variability driving changes over the North Pacific and surrounding continents—is now thought to be generated by processes internal to the climate system. According to this paradigm, the characteristic, irregular oscillations of the PDO arise from a collection of mechanisms involving ocean and atmosphere interactions in the North and tropical Pacific. Recent variations in the coupled ocean–atmosphere system, such as the 2015 El Ni?o, ought to have shifted the PDO into its positive phase. Yet, the PDO has been locked in a consistent downward trend for more than three decades, remanding nearby regions to a steady set of climate impacts. Here we show that the main multidecadal variations in the PDO index during the twentieth century, including the ongoing, decades-long negative trend, were largely driven by human emissions of aerosols and greenhouse gases rather than internal processes. This anthropogenic influence was previously undetected because the current generation of climate models systematically underestimate the amplitude of forced climate variability. A new attribution technique that statistically corrects for this error suggests that observed PDO impacts—including the ongoing multidecadal drought in the western United States—can be largely attributed to human activity through externally forced changes in the PDO. These results indicate that we need to rethink the attribution and projection of multidecadal changes in regional climate.
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