科研
科研
编译 | 冯维维
Nature, Volume 635 Issue 8037, 7 November 2024
《自然》, 第635卷，8037期，2024年11月7日
物理学Physics
Preferential occurrence of fast radio bursts in massive star-forming galaxies
快速射电暴在大质量恒星形成星系中的优先发生
▲ 作者：Kritti Sharma, Vikram Ravi, Liam Connor, Casey Law, Stella Koch Ocker, Myles Sherman, Nikita Kosogorov, Jakob Faber, Gregg Hallinan, Charlie Harnach, Greg Hellbourg, Rick Hobbs, David Hodge, Mark Hodges, James Lamb, Paul Rasmussen, Jean Somalwar, Sander Weinreb, David Woody, Joel Leja, Shreya Anand, Kaustav Kashyap Das, Yu-Jing Qin, Sam Rose,Yuhan Yao
▲ 链接：https://www.nature.com/articles/s41586-024-08074-9
▲ 摘要：
快速射电暴（FRB）是从银河系之外探测到的毫秒级天文事件。研究展示了由深天气阵列（DSA-110）发现的30个FRB宿主星系的恒星种群特性。该分析显示，与宇宙中恒星形成的发生相比，低质量FRB宿主明显不足。这意味着FRB是一种有偏差的恒星形成示踪剂，优先选择大质量的恒星形成星系。
这种偏差可能是由星系的金属丰度造成的，而金属丰度与恒星质量正相关。富含金属的环境可能有利于通过恒星合并形成磁星祖先。因为金属丰度较高的恒星不太紧凑，更有可能填满它们的罗氏叶，导致不稳定的质量传递。
尽管大质量恒星的内部没有对流，无法通过发电机产生强大的磁场，但人们认为，合并残留物具有形成磁星所必需的内部磁场强度。FRB优先出现在大质量恒星形成星系中，这表明合并残留物的核心坍缩超新星会优先形成磁星。
▲ Abstract：
Fast radio bursts (FRBs) are millisecond-duration events detected from beyond the Milky Way. Here, we present the stellar population properties of 30 FRB host galaxies discovered by the Deep Synoptic Array (DSA-110). Our analysis shows a marked deficit of low-mass FRB hosts compared with the occurrence of star formation in the Universe, implying that FRBs are a biased tracer of star formation, preferentially selecting massive star-forming galaxies. This bias may be driven by galaxy metallicity, which is positively correlated with stellar mass. Metal-rich environments may favour the formation of magnetar progenitors through stellar mergers, as higher-metallicity stars are less compact and more likely to fill their Roche lobes, leading to unstable mass transfer. Although massive stars do not have convective interiors to generate strong magnetic fields by dynamo11, merger remnants are thought to have the requisite internal magnetic-field strengths to result in magnetars. The preferential occurrence of FRBs in massive star-forming galaxies suggests that a core-collapse supernova of merger remnants preferentially forms magnetars.
Imaging shapes of atomic nuclei in high-energy nuclear collisions
高能核碰撞中原子核的成像形状
▲ 作者：STAR Collaboration
▲ 链接：https://www.nature.com/articles/s41586-024-08097-2
▲摘要：
原子核是自组织的多体量子系统，在飞米尺度空间内被强核力束缚。这些复杂的系统表现出各种各样的形状，传统上使用低能量的非侵入性光谱技术进行探索。然而，在这些能量下，它们的瞬时形状被长时间尺度的量子波动所掩盖，这使得直接观察变得具有挑战性。
研究者介绍了集体流辅助核形状成像方法。该方法通过以超相对论速度碰撞核并分析出核碎片的集体响应来成像核的整体形状。该技术捕获了原子核内空间物质分布的碰撞特定快照。通过流体动力学膨胀，在探测器中观察到的粒子动量分布上留下了图案。研究者在基态铀-238核的碰撞中测试了这种方法。铀-238核以其细长的轴对称形状而闻名。
研究结果表明，在核基态中有一个大的变形，与轴对称有轻微的偏离，和以前的低能实验大致一致。这种方法为核形状成像提供了一种新的方法，增强了人们对高能碰撞初始条件的理解，并解决了核结构跨能量尺度演化的重要问题。
▲ Abstract：
Atomic nuclei are self-organized, many-body quantum systems bound by strong nuclear forces within femtometre-scale space. These complex systems manifest a variety of shapes, traditionally explored using non-invasive spectroscopic techniques at low energies. However, at these energies, their instantaneous shapes are obscured by long-timescale quantum fluctuations, making direct observation challenging. Here we introduce the collective-flow-assisted nuclear shape-imaging method, which images the nuclear global shape by colliding them at ultrarelativistic speeds and analysing the collective response of outgoing debris. This technique captures a collision-specific snapshot of the spatial matter distribution within the nuclei, which, through the hydrodynamic expansion, imprints patterns on the particle momentum distribution observed in detectors. We benchmark this method in collisions of ground-state uranium-238 nuclei, known for their elongated, axial-symmetric shape. Our findings show a large deformation with a slight deviation from axial symmetry in the nuclear ground state, aligning broadly with previous low-energy experiments. This approach offers a new method for imaging nuclear shapes, enhances our understanding of the initial conditions in high-energy collisions and addresses the important issue of nuclear structure evolution across energy scales.
化学Chemistry
Carbon dioxide capture from open air using covalent organic frameworks
利用共价有机框架从空气中捕获二氧化碳
▲ 作者：Zihui Zhou, Tianqiong Ma, Heyang Zhang, Saumil Chheda, Haozhe Li, Kaiyu Wang, Sebastian Ehrling, Raynald Giovine, Chuanshuai Li, Ali H. Alawadhi, Marwan M. Abduljawad, Majed O. Alawad, Laura Gagliardi, Joachim Sauer & Omar M. Yaghi
▲ 链接：https://www.nature.com/articles/s41586-024-08080-x
▲ 摘要：
从空气中捕获二氧化碳（CO2）为应对气候变化和实现碳中和目标提供了一种有希望的方法。然而，开发一种具有高容量，快速动力学和低再生温度的耐用材料用于CO2捕获，特别是从复杂和动态的大气中捕获，仍然缺乏。
研究者合成了一种具有烯烃键的多孔晶体共价有机骨架（COF），并对其进行了结构表征，并通过胺引发剂的共价附着进行了合成修饰，从而在孔隙中生成多胺。这种COF（称为COF-999）可以从露天空气中捕获CO2。COF-999在干燥条件下的容量为0.96 mmol g-1，在50%相对湿度下的容量为2.05 mmol g-1。两者都来自400 ppm CO2。
研究者对该COF在加州伯克利的露天环境中进行了100多次吸附-解吸循环测试，发现其性能完全保持不变。COF-999是一种特殊的材料，用于从露天捕获二氧化碳，证明其循环稳定性，易于吸收CO2（在18.8分钟内达到一半容量）和低再生温度（60℃）。
▲ Abstract：
Capture of CO2 from the air offers a promising approach to addressing climate change and achieving carbon neutrality goals. However, the development of a durable material with high capacity, fast kinetics and low regeneration temperature for CO2 capture, especially from the intricate and dynamic atmosphere, is still lacking. Here a porous, crystalline covalent organic framework (COF) with olefin linkages has been synthesized, structurally characterized and post-synthetically modified by the covalent attachment of amine initiators for producing polyamines within the pores. This COF (termed COF-999) can capture CO2 from open air. COF-999 has a capacity of 0.96 mmol g–1 under dry conditions and 2.05 mmol g–1 under 50% relative humidity, both from 400ppm CO2. This COF was tested for more than 100 adsorption–desorption cycles in the open air of Berkeley, California, and found to fully retain its performance. COF-999 is an exceptional material for the capture of CO2 from open air as evidenced by its cycling stability, facile uptake of CO2 (reaches half capacity in 18.8 min) and low regeneration temperature (60°C).
Soft–hard zwitterionic additives for aqueous halide flow batteries
卤化物液流电池用软硬两性离子添加剂
▲ 作者：Gyohun Choi, Patrick Sullivan, Xiu-Liang Lv, Wenjie Li, Kwanpyung Lee, Haoyu Kong, Sam Gessler, J. R. Schmidt & Dawei Feng
▲ 链接：https://www.nature.com/articles/s41586-024-08079-4
▲ 摘要：
含卤化物阴极的水氧化还原液流电池有望用于可持续电网储能。研究者引入软硬两性离子捕集器（SH-ZITs）作为络合剂，由多卤化物络合的“软”阳离子基序和水溶性“硬”阴离子基序组成，以实现均匀的卤化物循环。
他们设计了300多个结构，并对13个结构进行了表征，展示了在均相水溶液中络合多卤化物、阻止阳离子交换膜交叉和改变电化学电极机制的能力。在标准阴极电池SoC为66.6%的条件下，液流电池在40毫安/平方厘米下的平均库仑效率超过99.9%。在超过2个月的1000多次循环后没有明显的衰减，并且在高温下也表现出稳定性。
有趣的是，SH-ZITs使卤化物阴极电解质在2摩尔/升下的均匀循环达到90%的SoC，揭示了以前未知的多卤化物体系有待研究。最终，SH-ZIT实现了超高的阴极电解质容量利用率。在80%的SoC下，每升可超过120安培小时，具有均匀循环能力，并且能够与混合液流电池中的锌阳极配对。
▲ Abstract：
Aqueous redox flow batteries with halide-based catholytes are promising for sustainable grid energy storage.Here we introduce soft–hard zwitterionic trappers (SH-ZITs) as complexing agents composed of a polyhalide-complexing ‘soft’ cationic motif and a water-soluble ‘hard’ anionic motif to enable homogeneous halide cycling. More than 300 structures were designed and 13 were characterized, showcasing the ability to complex polyhalides in homogeneous aqueous solution, to deter cation-exchange membrane crossover and to alter the electrochemical electrode mechanism. In flow battery cycling at a standard catholyte SoC of 66.6 per cent, an average coulombic efficiency of more than 99.9 per cent at 40milliamperes per square centimetre with no apparent decay was observed after more than 1,000 cycles over 2 months, with stability at elevated temperatures also demonstrated. Interestingly, SH-ZITs enable homogeneous cycling of the halide catholyte up to 90 per cent SoC at 2 moles per litre for bromide, revealing previously unknown polyhalide regimes to be studied. Ultimately, SH-ZIT enables ultrahigh catholyte capacity utilization up to over 120 ampere-hours per litre at 80 per cent SoC with homogeneous cycling as well as the ability to pair with a zinc anode in a hybrid flow battery.
气候学Climate
Vertical bedrock shifts reveal summer water storage in Greenland ice sheet
垂直基岩移动揭示格陵兰冰盖夏季储水量
▲ 作者：Jiangjun Ran, Pavel Ditmar, Michiel R. van den Broeke, Lin Liu, Roland Klees, Shfaqat Abbas Khan, Twila Moon, Jiancheng Li, Michael Bevis, Min Zhong, Xavier Fettweis, Junguo Liu, Brice No?l, C. K. Shum, Jianli Chen, Liming Jiang & Tonie van Dam
▲ 链接：https://www.nature.com/articles/s41586-024-08096-3
▲ 摘要：
随着北极变暖，格陵兰冰盖（GrIS）成为全球海平面上升的最大贡献者之一。然而，对冰川水的积累、储存和最终释放的过程仍然知之甚少。研究者发现在整个GrIS外围，有相当数量的夏季融水被暂时缓冲，在7月达到峰值，之后逐渐减少。
研究结果来源于通过分析全球导航卫星系统（GNSS）站点测量的基岩弹性变形，对离开GrIS的总水质量的时空行为进行量化。在融化季节，缓冲的融水使靠近GNSS站的基岩沉降最多约5毫米。从区域来看，融水的储存时间从东南部的4.5周到其他地区的9周不等。
研究还表明，从区域气候模型模拟的融水径流可能包含系统误差，在最温暖的年份需要进一步缩放约20%。这些结果表明，GNSS数据很有可能约束格陵兰岛鲜为人知的水文过程，从而为改进未来GrIS融化行为和相关海平面上升的预测奠定基础。
▲ Abstract：
The Greenland ice sheet (GrIS) is at present the largest single contributor to global-mass-induced sea-level rise, primarily because of Arctic amplification on an increasingly warmer Earth. However, the processes of englacial water accumulation, storage and ultimate release remain poorly constrained. Here we show that a noticeable amount of the summertime meltwater mass is temporally buffered along the entire GrIS periphery, peaking in July and gradually reducing thereafter. Our results arise from quantifying the spatiotemporal behaviour of the total mass of water leaving the GrIS by analysing bedrock elastic deformation measured by Global Navigation Satellite System (GNSS) stations. The buffered meltwater causes a subsidence of the bedrock close to GNSS stations of at most approximately 5 mm during the melt season. Regionally, the duration of meltwater storage ranges from 4.5 weeks in the southeast to 9 weeks elsewhere. We also show that the meltwater runoff modelled from regional climate models may contain systematic errors, requiring further scaling of up to about 20% for the warmest years. These results reveal a high potential for GNSS data to constrain poorly known hydrological processes in Greenland, forming the basis for improved projections of future GrIS melt behaviour and the associated sea-level rise.
Mortality caused by tropical cyclones in the United States
美国热带气旋造成的死亡率
▲ 作者：Rachel Young & Solomon Hsiang
▲ 链接：https://www.nature.com/articles/s41586-024-07945-5
▲ 摘要：
自然灾害在人类社会中引发了一系列复杂的事件。灾害发生后，直接观察到的死亡和损害得到了广泛的研究，但灾害间接造成的延迟下游后果很难追溯到最初的事件。热带气旋（TC，即飓风和热带风暴）在全球范围内广泛存在，并对经济产生持久影响，但其对健康的全面影响尚不清楚。
研究者对1930年至2015年期间美国所有TC对人类死亡率的长期影响进行了大规模评估。他们观察到，在每次地球物理事件发生后，过量死亡率会持续15年的强劲增长。他们据此估计，TC平均造成7000~11000多例死亡，超过了政府统计报告的24例立即死亡的平均值。通过追踪501次历史风暴的影响，他们计算出TC气候施加了一种未记录的死亡率负担，这解释了大西洋沿岸较高死亡率的很大一部分，大约相当于所有死亡人数的3.2%~5.1%。
这些发现表明，以前被认为对更广泛的公共卫生结果不重要的TC气候，是死亡风险分布的一个有意义的潜在驱动因素，特别是在婴儿（1岁以下）、1~44岁人群和黑人人群中。了解TC导致高死亡率的原因有助带来实质性的健康益处。
▲ Abstract：
Natural disasters trigger complex chains of events within human societies. Immediate deaths and damage are directly observed after a disaster and are widely studied, but delayed downstream outcomes, indirectly caused by the disaster, are difficult to trace back to the initial event. Tropical cyclones (TCs)—that is, hurricanes and tropical storms—are widespread globally and have lasting economic impacts, but their full health impact remains unknown. Here we conduct a large-scale evaluation of long-term effects of TCs on human mortality in the contiguous United States (CONUS) for all TCs between 1930 and 2015. We observe a robust increase in excess mortality that persists for 15 years after each geophysical event. We estimate that the average TC generates 7,000–11,000 excess deaths, exceeding the average of 24 immediate deaths reported in government statistics. Tracking the effects of 501 historical storms, we compute that the TC climate of CONUS imposes an undocumented mortality burden that explains a substantial fraction of the higher mortality rates along the Atlantic coast and is equal to roughly 3.2–5.1% of all deaths. These findings suggest that the TC climate, previously thought to be unimportant for broader public health outcomes, is a meaningful underlying driver for the distribution of mortality risk in CONUS, especially among infants (less than 1 year of age), people 1–44 years of age, and the Black population. Understanding why TCs induce this excess mortality is likely to yield substantial health benefits.
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