物理学Physics

▲ 作者：P. Winkler, M. Trunk, L. Hübner, A. Martinez de la Ossa, S. Jalas, M. Kirchen, I. Agapov, S. A. Antipov, R. Brinkmann, T. Eichner, A. Ferran Pousa, T. Hülsenbusch, G. Palmer, M. Schnepp, K. Schubert, M. Thévenet, P. A. Walker, C. Werle, W. P. Leemans & A. R. Maier 

▲ 链接：

https://www.nature.com/articles/s41586-025-08772-y

▲ 摘要：

提供高质量相对论电子束的射频（RF）加速器是使许多科学领域以及工业和医疗应用成为可能的重要资源。20年前，支持比现代射频腔高几个数量级电场的激光等离子体加速器第一次产生了准单能电子束。

研究者报告了使用主动能量压缩产生激光等离子体电子束，从而产生迄今为止仅与现代RF加速器相关的性能。使用磁弯，电子束首先纵向拉伸以印记能量相关性，然后用有源射频腔去除。

由此产生的能量扩散和能量抖动减少了一个数量级以上，达到了现代同步加速器的可接受标准，从而为紧凑型存储环注入器和其他应用开辟了道路。

▲ Abstract：

Radio-frequency (RF) accelerators providing high-quality relativistic electron beams are an important resource enabling many areas of science, as well as industrial and medical applications. Two decades ago, laser-plasma accelerators1 that support orders of magnitude higher electric fields than those provided by modern RF cavities produced quasi-monoenergetic electron beams for the first time. Here we report the generation of a laser-plasma electron beam using active energy compression, resulting in a performance so far only associated with modern RF-based accelerators. Using a magnetic chicane, the electron bunch is first stretched longitudinally to imprint an energy correlation, which is then removed with an active RF cavity. The resulting energy spread and energy jitter are reduced by more than an order of magnitude to below the permille level, meeting the acceptance criteria of a modern synchrotron, thereby opening the path to a compact storage ring injector and other applications.

▲ 作者：Ping Zhao, Vijay Shekhawat, Marcello Girardi, Zonglong He, Victor Torres-Company & Peter A. Andrekson 

▲ 链接：

https://www.nature.com/articles/s41586-025-08824-3

▲ 摘要：

四波混频是一种非线性光学现象，可用于宽带低噪声光放大和波长转换。它在通信、计算、计量、成像和量子光学方面的应用已经得到了广泛的研究。光集成波导具有占地面积小、非线性大、色散工程能力强等优点，是实现高增益、大带宽四波混频的理想选择，而异常色散是实现四波混频的关键条件。

各种基于硅、砷化铝镓和非线性玻璃的波导已经被研究过，但是由于常规的设计方法导致异常色散导致多模式工作，因此受到相当大的增益和带宽降低的影响。研究者提出了一种同时具有单模工作和异常色散的非线性波导的制作方法，用于超宽带工作和高效四波混频。

虽然他们在氮化硅波导中实现了这一点，但该设计方法也可以用于其他平台。通过使用高阶色散，他们在这些超低损耗集成波导中实现了前所未有的300纳米以上的放大带宽，实现了100 Gbit s?1数据在200纳米以上单光通道内的无罚全光波长转换。这些单模色散设计的非线性波导可以成为各种非线性光子学应用的实用基石。

▲ Abstract：

Four-wave mixing is a nonlinear optical phenomenon that can be used for wideband low-noise optical amplification and wavelength conversion. It has been extensively investigated for applications in communications1, computing, metrology, imaging and quantum optics. With its advantages of small footprint, large nonlinearity and dispersion-engineering capability, optical integrated waveguides are excellent candidates for realizing high-gain and large-bandwidth four-wave mixing for which anomalous dispersion is a key condition. Various waveguides based on, for example, silicon, aluminium gallium arsenide and nonlinear glass have been studied, but suffer from considerable gain and bandwidth reductions, as conventional design approaches for anomalous dispersion result in multi-mode operation. We present a methodology for fabricating nonlinear waveguides with simultaneous single-mode operation and anomalous dispersion for ultra-broadband operation and high-efficiency four-wave mixing. Although we implemented this in silicon nitride waveguides, the design approach can be used with other platforms as well. By using higher-order dispersion, we achieved unprecedented amplification bandwidths of more than 300?nm in these ultra-low-loss integrated waveguides. Penalty-free all-optical wavelength conversion of 100?Gbit?s?1data in a single optical channel of over 200?nm was realized. These single-mode dispersion-engineered nonlinear waveguides could become practical building blocks in various nonlinear photonics applications.

化学Physics

▲ 作者：Bao Qiu, Yuhuan Zhou, Haoyan Liang, Minghao Zhang, Kexin Gu, Tao Zeng, Zhou Zhou, Wen Wen, Ping Miao, Lunhua He, Yinguo Xiao, Sven Burke, Zhaoping Liu & Ying Shirley Meng 

▲ 链接：

https://www.nature.com/articles/s41586-025-08765-x

▲ 摘要：

由于材料的热力学和电化学性质之间错综复杂的相互作用，材料内部的结构紊乱产生了令人着迷的现象。氧氧化还原（OR）电化学提供了容量限制的突破，同时引起结构紊乱，降低了电化学可逆性。固体热膨胀的传统解释依赖于格律乃森关系，将膨胀系数与晶格的非调和性联系起来。然而，由于这种系统中未探索的动态无序-有序转变，这种范式可能不适用于OR材料。

研究者发现，OR活性材料中存在负热膨胀，其系数值为?14.4(2)× 10?6℃?1，这归因于热驱动的无序-有序转变。OR行为的调制不仅可以精确控制材料的热膨胀系数，而且为零热膨胀功能材料的设计建立了一个实用的框架。

他们还证明了材料内部结构无序的恢复也可以通过电化学驱动力来完成。通过调整截止电压，对放电电压变化的评估表明，几乎可达100%结构恢复。

这一发现为通过操作电化学过程将OR活性材料恢复到原始状态提供了一条途径，提出了一种新的缓解策略来解决电压衰减的持续挑战。

▲ Abstract：

Structural disorder within materials gives rise to fascinating phenomena, attributed to the intricate interplay of their thermodynamic and electrochemical properties. Oxygen-redox (OR) electrochemistry offers a breakthrough in capacity limits, while inducing structural disorder with reduced electrochemical reversibility. The conventional explanation for the thermal expansion of solids relies on the Grüneisen relationship, linking the expansion coefficient to the anharmonicity of the crystal lattice6. However, this paradigm may not be applicable to OR materials due to the unexplored dynamic disorder–order transition in such systems. Here we reveal the presence of negative thermal expansion with a large coefficient value of ?14.4(2)?×?10?6°C?1in OR active materials, attributing this to thermally driven disorder–order transitions. The modulation of OR behaviour not only enables precise control over the thermal expansion coefficient of materials, but also establishes a pragmatic framework for the design of functional materials with zero thermal expansion. Furthermore, we demonstrate that the reinstatement of structural disorder within the material can also be accomplished through the electrochemical driving force. By adjusting the cut-off voltages, evaluation of the discharge voltage change indicates a potential for nearly 100% structure recovery. This finding offers a pathway for restoring OR active materials to their pristine state through operando electrochemical processes, presenting a new mitigation strategy to address the persistent challenge of voltage decay.

▲ 作者：Konstantin Khivantsev, Hien Pham, Mark H. Engelhard, Hristiyan A. Aleksandrov, Libor Kovarik, Mark Bowden, Xiaohong Shari Li, Jinshu Tian, Iskra Z. Koleva, Inhak Song, Wenda Hu, Xinyi Wei, Yipeng Sun, Pascaline Tran, Trent R. Graham, Dong Jiang, David P. Dean, Christian J. Breckner, Jeffrey T. Miller, Georgi N. Vayssilov, János Szanyi, Abhaya Datye & Yong Wang 

▲ 链接：

https://www.nature.com/articles/s41586-025-08684-x

▲ 摘要：

氧化铝负载的氧化铈纳米颗粒广泛应用于各种催化反应，特别是与铂族金属（PGM）的结合。通过理论计算，研究者发现，在蒸汽中CO和NO存在下，在750至1000℃之间处理这些催化剂（还原气氛下的反应性处理）会导致二氧化铈纳米粒子分散到高密度2D（大约一个原子层薄）CexOy畴中。

这些结构域密集地覆盖在氧化铝表面，表现出显著增强的氧迁移和存储能力，有利于氧气的提取和Ce3+位点和氧空位的形成。因此，这些催化剂——无论是否含有PGM，如Rh和pt——在几个工业上重要的催化反应中表现出更高的活性，包括NO和N2O的还原，以及CO和NO的氧化，即使在恶劣的老化条件下也是如此。

研究展示的催化剂结构，在通常导致烧结的条件下具有优越的氧化还原性能，为更有效的金属-二氧化铈催化剂的增强一般催化提供了一条途径。

▲ Abstract：

Ceria nanoparticles supported on alumina are widely used in various catalytic reactions, particularly in conjunction with platinum group metals (PGMs). Here we found that treating these catalysts at temperatures between 750 and about 1,000?°C in the presence of CO and NO in steam (reactive treatment under reducing atmosphere) leads to the dispersion of ceria nanoparticles into high-density 2D (roughly one atomic layer thin) CexOydomains, as confirmed by microscopy, X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), infrared spectroscopy and density functional theory (DFT) calculations. These domains, which densely cover the alumina, exhibit substantially enhanced oxygen mobility and storage capacity, facilitating easier extraction of oxygen and the formation of Ce3+sites and oxygen vacancies. As a result, these catalysts—whether with or without PGMs, such as Rh and Pt—show improved activity for several industrially important catalytic reactions, including NO and N2O reduction, as well as CO and NO oxidation, even after exposure to harsh ageing conditions. This study shows a catalyst architecture with superior redox properties under conditions that typically cause sintering, offering a pathway to more efficient metal–ceria catalysts for enhanced general catalysis.

生态与古气候Ecology & paleoclimate

▲ 作者：Thorsten Wiegand, Xugao Wang, Samuel M. Fischer, Nathan J. B. Kraft, Norman A. Bourg, Warren Y. Brockelman, Guanghong Cao, Min Cao, Wirong Chanthorn, Chengjin Chu, Stuart Davies, Sisira Ediriweera, C. V. Savitri Gunatilleke, I. A. U. Nimal Gunatilleke, Zhanqing Hao, Robert Howe, Mingxi Jiang, Guangze Jin, W. John Kress, Buhang Li, Juyu Lian, Luxiang Lin, Feng Liu, Keping Ma,Andreas Huth

▲ 链接：

https://www.nature.com/articles/s41586-025-08604-z

▲ 摘要：

寻找植物群落空间结构和动态的简单原理是生态学的一个长期挑战。研究者对21个大型样地720种树种的空间格局及其对物种共存的影响进行了综合分析。

结果表明，相对于丰度较高的物种，低丰度物种的空间聚集性更强。此外，从热带森林到温带森林，这种负聚集-丰度关系的强度呈纬度梯度增加。

根据最近的研究，他们认为动物种子传播的纬度梯度和菌根关联可能共同产生了这种模式。通过将观察到的空间格局整合到种群模型中，他们从空间格局、人口统计学、生态位重叠和迁移等方面得出了物种从低丰度入侵的条件。

对所分析的720种树种的空间入侵条件评价表明，温带森林和热带森林都在相似程度上满足入侵标准，但它们的空间格局决定了不同的策略。该方法为将观察到的空间模式整合到生态学理论中开辟了新的途径，并强调了更详细地理解邻里尺度空间模式和多种生态过程之间相互作用的必要性。

▲ Abstract：

The search for simple principles that underlie the spatial structure and dynamics of plant communities is a long-standing challenge in ecology. Here we present a comprehensive analysis of the spatial patterns of 720 tree species in 21 large forest plots and their consequences for species coexistence. We show that species with low abundance tend to be more spatially aggregated than more abundant species. Moreover, there is a latitudinal gradient in the strength of this negative aggregation–abundance relationship that increases from tropical to temperate forests. We suggest, in line with recent work, that latitudinal gradients in animal seed dispersal and mycorrhizal associations,may jointly generate this pattern. By integrating the observed spatial patterns into population models, we derive the conditions under which species can invade from low abundance in terms of spatial patterns, demography, niche overlap and immigration. Evaluation of the spatial-invasion condition for the 720 tree species analysed suggests that temperate and tropical forests both meet the invasion criterion to a similar extent but through contrasting strategies conditioned by their spatial patterns. Our approach opens up new avenues for the integration of observed spatial patterns into ecological theory and underscores the need to understand the interaction among spatial patterns at the neighbourhood scale and multiple ecological processes in greater detail.