《自然》（20221006出版）一周论文导读

编译 | 冯维维

Nature, 6 OCTOBER 2022, VOL 610, ISSUE 7930

《自然》2022年10月6日，第610卷，7930期

物理学Physics

Magnetic fields of 30 to 100 kG in the cores of red giant stars

红巨星的核心有30到100千高斯的磁场

作者：Gang Li, Sébastien Deheuvels, Jérôme Ballot & François Lignières

链接：

https://www.nature.com/articles/s41586-022-05176-0

摘要：

红巨星是一颗逐渐演化的低质量或中质量恒星，它耗尽了中心的氢含量，只剩下氦核和燃氢外壳。作者报道了用开普勒13号卫星观测到的三颗红巨星核心磁场的测量结果。这些场引起的位移破坏了偶极模多胞胎的对称性。

因此，他们测量的场强度范围从约30千高斯到约100千高斯的氢燃烧壳附近，并对场拓扑结构进行约束。

Abstract：

A red giant star is an evolved low- or intermediate-mass star that has exhausted its central hydrogen content, leaving a helium core and a hydrogen-burning shell. Here we report the measurement of magnetic fields in the cores of three red giant stars observed with the Kepler13 satellite. The fields induce shifts that break the symmetry of dipole mode multiplets. We thus measure field strengths ranging from about 30 kilogauss to about 100 kilogauss in the vicinity of the hydrogen-burning shell and place constraints on the field topology.

Extending the spectrum of fully integrated photonics to submicrometre wavelengths

将完全集成光子学的光谱扩展到亚微米波长

作者：Minh A. Tran, Chong Zhang, Theodore J. Morin, Lin Chang, Sabyasachi Barik, Zhiquan Yuan, Woonghee Lee, Glenn Kim, Aditya Malik, Zeyu Zhang, Joel Guo, Heming Wang, Boqiang Shen, Lue Wu, Kerry Vahala, John E. Bowers, Hyundai Park & Tin Komljenovic

链接：

https://www.nature.com/articles/s41586-022-05119-9

摘要：

集成光子学深刻影响了支撑现代社会的众多技术。在一个芯片上制造一个完整的光学系统的能力提供了无与伦比的可扩展性、重量、成本和功率效率。作者通过将III-V材料与硅晶圆上的氮化硅波导直接结合，提出了新一代集成光子学。

使用该技术，他们提出了一个光子能量大于硅带隙的完全集成PIC，演示了基本的光子构建模块，包括激光器、放大器、光电探测器、调制器和被动，都可在亚微米波长下操作。利用该平台，他们实现了集成激光器在短波内前所未有的相干性和可调性。

此外，通过利用这种更高的光子能量，作者展示了高超的高温性能和高温下khz级的基本线宽。鉴于在短波长的许多潜在应用，这种集成策略的成功解锁了广泛的新型集成光子学应用。

Abstract：

Integrated photonics has profoundly affected a wide range of technologies underpinning modern society. The ability to fabricate a complete optical system on a chip offers unrivalled scalability, weight, cost and power efficiency. Here, we present a new generation of integrated photonics by directly uniting III–V materials with silicon nitride waveguides on Si wafers. Using this technology, we present a fully integrated PIC at photon energies greater than the bandgap of silicon, demonstrating essential photonic building blocks, including lasers, amplifiers, photodetectors, modulators and passives, all operating at submicrometre wavelengths. Using this platform, we achieve unprecedented coherence and tunability in an integrated laser at short wavelength. Furthermore, by making use of this higher photon energy, we demonstrate superb high-temperature performance and kHz-level fundamental linewidths at elevated temperatures. Given the many potential applications at short wavelengths, the success of this integration strategy unlocks a broad range of new integrated photonics applications.

大气物理Atmospheric Physics

Continuous air purification by aqueous interface filtration and absorption

通过水界面过滤和吸收连续净化空气

作者：Yunmao Zhang, Yuhang Han, Xiaoliang Ji, Duyang Zang, Long Qiao, Zhizhi Sheng, Chunyan Wang, Shuli Wang, Miao Wang, Yaqi Hou, Xinyu Chen & Xu Hou

链接：

https://www.nature.com/articles/s41586-022-05124-y

摘要：

空气颗粒物污染对人体健康的不利影响促进了过滤空气中颗粒物的净化系统的发展。为了保持性能，过滤器单元在某个时刻不可避免地必须更换，这需要维护，涉及成本和产生固体废物。

作者展示了一种离子掺杂的共轭聚合物涂层基质与选定的功能性液体浸润，能够实现高效、连续和免维护的空气净化。

当需要净化的空气以气泡的形式通过系统时，功能流体为过滤和去除空气中的颗粒物和污染物分子提供了界面。理论建模和实验结果表明，该系统具有较高的效率和鲁棒性：一次性空气净化效率可达99.6%，抑尘能力可达950 g m 2。

该系统耐用，耐污染和腐蚀，作为过滤器的液体可以重复使用和调整，也可以去除细菌或气味。作者预计，该净化方法将有助于开发专门的空气净化器，这可能被证明在医院、工厂和矿山等环境中是有用的。

Abstract：

The adverse impact of particulate air pollution on human health has prompted the development of purification systems that filter particulates out of air. To maintain performance, the filter units must inevitably be replaced at some point, which requires maintenance, involves costs and generates solid waste. Here we show that an ion-doped conjugated polymer-coated matrix infiltrated with a selected functional liquid enables efficient, continuous and maintenance-free air purification. As the air to be purified moves through the system in the form of bubbles, the functional fluid provides interfaces for filtration and for removal of particulate matter and pollutant molecules from air. Theoretical modelling and experimental results demonstrate that the system exhibits high efficiency and robustness: its one-time air purification efficiency can reach 99.6%, and its dust-holding capacity can reach 950 g m 2. The system is durable and resistant to fouling and corrosion, and the liquid acting as filter can be reused and adjusted to also enable removal of bacteria or odours. We anticipate that our purification approach will be useful for the development of specialist air purifiers that might prove useful in a settings such as hospitals, factories and mines.

Invisible ship tracks show large cloud sensitivity to aerosol

看不见的航迹显示云层对气溶胶有很大的敏感性

作者：Peter Manshausen, Duncan Watson-Parris, Matthew W. Christensen, Jukka-Pekka Jalkanen & Philip Stier

链接：

https://www.nature.com/articles/s41586-022-05122-0

摘要：

云的反射率对大气气溶胶浓度很敏感，因为气溶胶提供凝结核，水在凝结核上凝结。人类活动导致的气溶胶浓度增加会影响液滴数量浓度、液态水和云分数，但这些变化具有很大的不确定性。船舶航迹，即卫星图像上可见的被污染的云团，是量化气溶胶与云团相互作用的主要工具之一。

然而，只有一小部分被船舶污染的云层能显示出船舶的航迹。作者研究表明，即使在卫星图像中看不到船舶轨迹，气溶胶排放也会显著改变云的特性。

他们开发了一种量化航运对所有云的影响的新方法，表明当没有可见的轨迹时，云滴数量增加，液态水响应更积极。他们直接在大西洋的贸易积云区探测到由航运引起的云性质变化，这些积云区几乎没有可见的痕迹。

研究结果表明，先前对船舶航迹的研究由于只关注卫星图像中的可见航迹而存在选择偏差。他们发现的强液态水路径响应转化为对气候更大的气溶胶冷却效应，可能掩盖了比观测到的温度趋势所显示的更高的气候敏感性。

Abstract：

Cloud reflectivity is sensitive to atmospheric aerosol concentrations because aerosols provide the condensation nuclei on which water condenses. Increased aerosol concentrations due to human activity affect droplet number concentration, liquid water and cloud fraction, but these changes are subject to large uncertainties. Ship tracks, long lines of polluted clouds that are visible in satellite images, are one of the main tools for quantifying aerosol–cloud interactions. However, only a small fraction of the clouds polluted by shipping show ship tracks. Here we show that even when no ship tracks are visible in satellite images, aerosol emissions change cloud properties substantially. We develop a new method to quantify the effect of shipping on all clouds, showing a cloud droplet number increase and a more positive liquid water response when there are no visible tracks. We directly detect shipping-induced cloud property changes in the trade cumulus regions of the Atlantic, which are known to display almost no visible tracks. Our results indicate that previous studies of ship tracks were suffering from selection biases by focusing only on visible tracks from satellite imagery. The strong liquid water path response we find translates to a larger aerosol cooling effect on the climate, potentially masking a higher climate sensitivity than observed temperature trends would otherwise suggest.

化学Chemistry

Compositionally complex doping for zero-strain zero-cobalt layered cathodes

零应变零钴层状阴极的复合掺杂

作者：Rui Zhang, Chunyang Wang, Peichao Zou, Ruoqian Lin, Lu Ma, Liang Yin, Tianyi Li, Wenqian Xu, Hao Jia, Qiuyan Li, Sami Sainio, Kim Kisslinger, Stephen E. Trask, Steven N. Ehrlich, Yang Yang, Andrew M. Kiss, Mingyuan Ge, Bryant J. Polzin, Sang Jun Lee, Wu Xu, Yang Ren & Huolin L. Xin

链接：

https://www.nature.com/articles/s41586-022-05115-z

摘要：

钴价格的高度波动和钴开采的地缘政治限制使得减少钴的用量成为汽车行业的迫切需求。由于其高能量密度和低成本的优势，高镍低钴或无钴（零钴）层状阴极成为下一代锂离子电池最有前途的阴极。

然而，目前的高镍正极材料无一例外地存在着固有的热稳定性和化学力学不稳定性以及循环寿命不足等问题。在这里，作者通过使用一种新的成分络合物(高熵)掺杂策略，成功地制备了一个高镍，零钴的层状阴极，具有极高的热稳定性和循环稳定性。

结合X射线衍射、透射电子显微镜和纳米断层扫描，他们发现阴极在较宽的电化学窗口内呈现几乎为零的体积变化，从而大大减少了晶格缺陷和局部应变诱导裂纹。原位加热实验表明，新阴极的热稳定性明显提高，达到了超稳定NMC-532的水平。

由于热稳定性的显著提高和零体积变化，它表现出极大的提高容量保留。这项研究解决了高镍、零钴正极材料长期存在的安全性和稳定性问题，为安全、长寿命锂离子电池提供了商业上可行的正极，并提供了抑制插层电极应变和相变的通用策略。

Abstract：

The high volatility of the price of cobalt and the geopolitical limitations of cobalt mining have made the elimination of Co a pressing need for the automotive industry. Owing to their high energy density and low-cost advantages, high-Ni and low-Co or Co-free (zero-Co) layered cathodes have become the most promising cathodes for next-generation lithium-ion batteries. However, current high-Ni cathode materials, without exception, suffer severely from their intrinsic thermal and chemo-mechanical instabilities and insufficient cycle life. Here, by using a new compositionally complex (high-entropy) doping strategy, we successfully fabricate a high-Ni, zero-Co layered cathode that has extremely high thermal and cycling stability. Combining X-ray diffraction, transmission electron microscopy and nanotomography, we find that the cathode exhibits nearly zero volumetric change over a wide electrochemical window, resulting in greatly reduced lattice defects and local strain-induced cracks. In-situ heating experiments reveal that the thermal stability of the new cathode is significantly improved, reaching the level of the ultra-stable NMC-532. Owing to the considerably increased thermal stability and the zero volumetric change, it exhibits greatly improved capacity retention. This work, by resolving the long-standing safety and stability concerns for high-Ni, zero-Co cathode materials, offers a commercially viable cathode for safe, long-life lithium-ion batteries and a universal strategy for suppressing strain and phase transformation in intercalation electrodes.

Photoexcited nitroarenes for the oxidative cleavage of alkenes

光激发硝基芳烃对烯烃的氧化裂解

作者：Alessandro Ruffoni, Charlotte Hampton, Marco Simonetti & Daniele Leonori

链接：

https://www.nature.com/articles/s41586-022-05211-0

摘要：

烯烃的氧化裂解是将原料转化为高价值合成中间体的一个完整过程。

在一个化学步骤中实现这一点最可行的方法是利用臭氧；然而，由于臭氧溶解产品的爆炸性，这在技术和安全方面提出了挑战。作者报道了一种替代方法，以实现氧化裂解烯烃使用硝基芳烃和紫光照射。

他们证明了光激发硝基芳烃是一种有效的臭氧替代物，它能与烯烃发生简单的自由基[3+2]环加成。由此产生的“掺氮”臭氧是可以安全处理的，并在温和水解条件下得到相应的羰基产物。这些特征使所有类型的烯烃在广泛的常用有机官能团存在的情况下被控制裂解。

此外，通过利用电子、空间和中介极性效应，硝基芳烃的结构和功能多样性为在含有多个烯烃的底物中获得位点选择性提供了一个模块化平台。

Abstract：

The oxidative cleavage of alkenes is an integral process that converts feedstock materials into high-value synthetic intermediates. The most viable method to achieve this in one chemical step is with ozone; however, this poses technical and safety challenges owing to the explosive nature of ozonolysis products. Here we report an alternative approach to achieve oxidative cleavage of alkenes using nitroarenes and purple-light irradiation. We demonstrate that photoexcited nitroarenes are effective ozone surrogates that undergo facile radical [3+2] cycloaddition with alkenes. The resulting ‘N-doped’ ozonides are safe to handle and lead to the corresponding carbonyl products under mild hydrolytic conditions. These features enable the controlled cleavage of all types of alkenes in the presence of a broad array of commonly used organic functionalities. Furthermore, by harnessing electronic, steric and mediated polar effects, the structural and functional persity of nitroarenes has provided a modular platform to obtain site selectivity in substrates containing more than one alkene.