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发布日期：2024-07-16 作者：开博
Nature, 25 April 2024, Volume 628 Issue 8009
《天然》2024年4月25日，第628卷，8009期
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天文学Astronomy
Stripped-envelope supernova light curves argue for central engine activity
操纵剥离包层超新星的光曲线证实中间引擎的勾当
▲ 作者：ósmar Rodríguez, Ehud Nakar Dan Maoz
▲ 链接：
https://www.nature.com/articles/s41586-024-07262-x
▲ 摘要：
在此，我们阐发了54个被充实不雅测到的剥离包层超新星样本的能量出入，并提出了统计上显著的、根基不受模子限制的不雅测证据，并证实了此中年夜大都（多是全数）存在非放射性动力源。
我们斟酌了可能致使这一成果的能量来历或公道的系统误差，结论认为最公道的注释是存在一个持久的中间引擎，在爆炸后延续运行约103–106?秒。我们从不雅察成果中揣度出引擎机能的限制身分。
例如，假如中间引擎是一颗磁化的中子星，那末初始磁场约为1015 G，初始扭转周期为1—100 ms，这注解剥离包层超新星多是磁星构成的主要前提。
▲ Abstract：
Here we analyse the energy budget of a sample of 54 well-observed stripped-envelope supernovae of all sub-types and present statistically significant, largely model-independent, observational evidence for a non-radioactive power source in most of them (and possibly in all). We consider various energy sources, or alternatively, plausible systematic errors, that could drive this result, and conclude that the most likely option is the existence of a long-lived central engine, operating over ≈103–106?s after the explosion. We infer, from the observations, constraints on the engine properties. If, for example, the central engine is a magnetized neutron star, then the initial magnetic field is ≈1015?G and the initial rotation period is 1–100?ms, suggesting that stripped-envelope supernovae may constitute the formation events of the objects known as magnetars.
物理学Physics
One-dimensional proximity superconductivity in the quantum Hall regime
量子霍尔系统中的一维超导体
▲ 作者：Julien Barrier, Minsoo Kim et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07271-w
▲ 摘要：
在此，我们展现了最小扭曲双层石墨烯中的畴壁在量子霍尔系统中撑持异常壮大的临近超导性，答应约瑟夫森结在接近超导电极的上临界场的运行。
我们发现临界电流长短振荡的，而且在全部量子化场规模内几近不变，数值受限在驻留在畴壁内的严酷一维电子通道的量子电导。该系统在量子化场中撑持Andreev束厄局促态的能力是并世无双的，并为进一步摸索供给了更多标的目的。
▲ Abstract：
Here we show that domain walls in minimally twisted bilayer graphene support exceptionally robust proximity superconductivity in the quantum Hall regime, allowing Josephson junctions to operate in fields close to the upper critical field of superconducting electrodes. The critical current is found to be non-oscillatory and practically unchanging over the entire range of quantizing fields, with its value being limited by the quantum conductance of ballistic, strictly one-dimensional, electronic channels residing within the domain walls. The system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration.
Optical clocks at sea
海上光学钟
▲ 作者：Jonathan D. Roslund, Arman Cing?z et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07225-2
▲ 摘要：
在此，我们陈述在移动平台上运行的光学时钟的尺寸、机能和情况敏感性的组合成长。这个35 l时钟连系了份子碘光谱仪，光纤频率梳和调控电子装备。3个如许的时钟在承平洋的一所军舰上持续运行了20天，天天的计时误差在300皮秒以下。
这类时钟的机能与氢脉泽相当，但体积只有前者的十分之一。在海上操作高机能时钟具有挑战性，而且对导航相当主要。此次展现标记着一项重年夜的手艺前进，预示着将来光学计时收集的到来。
▲ Abstract：
Here we report the development of optical clocks with the requisite combination of size, performance and environmental insensitivity for operation on mobile platforms. The 35?l clock combines a molecular iodine spectrometer, fibre frequency comb and control electronics. Three of these clocks operated continuously aboard a naval ship in the Pacific Ocean for 20 days while accruing timing errors below 300?ps per day. The clocks have comparable performance to active hydrogen masers in one-tenth the volume. Operating high-performance clocks at sea has been historically challenging and continues to be critical for navigation. This demonstration marks a significant technological advancement that heralds the arrival of future optical timekeeping networks.
材料科学Material Science
Graphene nanoribbons grown in hBN stacks for high-performance electronics
用在高机能电子器件的hBN堆叠中发展的石墨烯纳米带
▲ 作者：Bosai Lyu, Jiajun Chen et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07243-0
▲ 摘要：
在这里，我们陈述高质量石墨烯纳米带（GNRs）在hBN堆叠中的无转移直接发展。发展的嵌入式GNRs具有超长(（高达0.25 mm）、超窄（小在5 nm）和具有之字形边沿的同手性等很是抱负的特征。我们的原子摹拟注解，嵌入发展的机制触及在AA堆叠的hBN层之间滑动时GNR的超低磨擦。
操纵发展的布局，我们展现了嵌入式GNR场效应器件的无转移制造，这一器件在室温下表示出优良机能，迁徙率高达4,600 cm2?V–1?s–1，开关比高达106。
▲ Abstract：
Here we report the transfer-free direct growth of high-quality graphene nanoribbons (GNRs) in hBN stacks. The as-grown embedded GNRs exhibit highly desirable features being ultralong (up to 0.25?mm), ultranarrow ( 5?nm) and homochiral with zigzag edges. Our atomistic simulations show that the mechanism underlying the embedded growth involves ultralow GNR friction when sliding between AA′-stacked hBN layers. Using the grown structures, we demonstrate the transfer-free fabrication of embedded GNR field-effect devices that exhibit excellent performance at room temperature with mobilities of up to 4,600?cm2?V–1?s–1 and on–off ratios of up to 106.
Digital colloid-enhanced Raman spectroscopy by single-molecule counting
单份子计数数字胶体加强拉曼光谱
▲ 作者：Xinyuan Bi, Daniel M. Czajkowsky, Zhifeng Shao Jian Ye
▲ 链接：
https://www.nature.com/articles/s41586-024-07218-1
▲ 摘要：
在此，我们注解，利用数字（纳米）胶体加强拉曼光谱，可以经由过程单份子计数常规地在很是低浓度下实现普遍方针份子的可反复量化，仅受丈量进程的泊松噪声的限制。
因为金属胶体纳米粒子（包罗羟胺还原银胶体）加强这些振动特点，可以在常规前提下年夜范围制造，我们估计数字（纳米）胶体加强拉曼光谱将成为靠得住和超活络检测包罗对人类健康很是主要的各类阐发物的首选手艺。
▲ Abstract：
Here, as a proof of concept, we show that, using digital (nano)colloid-enhanced Raman spectroscopy, reproducible quantification of a broad range of target molecules at very low concentrations can be routinely achieved with single-molecule counting, limited only by the Poisson noise of the measurement process. As metallic colloidal nanoparticles that enhance these vibrational signatures, including hydroxylamine–reduced-silver colloids, can be fabricated at large scale under routine conditions, we anticipate that digital (nano)colloid-enhanced Raman spectroscopy will become the technology of choice for the reliable and ultrasensitive detection of various analytes, including those of great importance for human health.
生物学Biology
Hybrid speciation driven by multilocus introgression of ecological traits
由生态性状多点引入驱动的杂交物种构成
▲ 作者：Neil Rosser, Fernando Seixas et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07开博体育263-w
▲ 摘要：
在此，我们将种群基因组阐发与物种特异性性状的数目性状位点定位相连系，研究了Heliconius胡蝶杂交物种构成的案例。我们展现了Heliconius elevatus是一个与双亲同域的杂交物种，而且作为一个自力演变的品系延续存在了最少18万年。
虽然与此中一个亲本Heliconius pardalinus之间的基因活动遍及且延续，使它们基因组的 99% 都产生了同质化。剩下的1%遗传自另外一个亲本Heliconius melpomene，普遍漫衍在H. elevatus的基因组中，构成了一个个与H. pardalinus分歧的分化。
这些分化包括多种在粉碎性选择下的特点，包罗色彩模式、同党外形、寄主植物偏好、性信息素和配头选择。整体来讲，这些特点将H. elevatu置在本身的顺应岑岭，并答应与双亲共存。我们的研究成果注解，物种构成是由生态性状的引入驱动的，而且在多位点遗传布局下，基因流的物种构成是可能的。
▲ Abstract：
Here we combine population genomic analysis with quantitative trait locus mapping of species-specific traits to examine a case of hybrid speciation in Heliconius butterflies. We show that Heliconius elevatus is a hybrid species that is sympatric with both parents and has persisted as an independently evolving lineage for at least 180,000 years. This is despite pervasive and ongoing gene flow with one parent, Heliconius pardalinus, which homogenizes 99% of their genomes. The remaining 1% introgressed from the other parent, Heliconius melpomene, and is scattered widely across the H. elevatus genome in islands of divergence from H. pardalinus. These islands contain multiple traits that are under disruptive selection, including colour pattern, wing shape, host plant preference, sex pheromones and mate choice. Collectively, these traits place H. elevatus on its own adaptive peak and permit coexistence with both parents. Our results show that speciation was driven by introgression of ecological traits, and that speciation with gene flow is possible with a multilocus genetic architecture.
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