Nature,23 May 2024, VOL 629, ISSUE 8013

《天然》2024年5月23日，第629卷，8013期

太阳发机电效应始在太阳外貌四周

▲ 作者：Geoffrey M. Vasil, Daniel Lecoanet, Kyle Augustson, Keaton J. Burns, Jeffrey S. Oishi, Benjamin P. Brown, et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07315-1

▲ 择要：

太阳磁发机电效应周期具备怪异模式：太阳黑子呈现的流传区域位在纬度30°四周，每一11年于赤道四周消散。此外，被称为旋转振荡的纵向流动与太阳黑子迁徙紧密亲密相干，毫无疑难具备配合缘故原由。

与表示这些征象深层发源的理论相反，日震学将低纬度旋转振荡切确定位在太阳外层的5~10%，即近太阳外貌剪切层。于该区域内，向内增长的差动扭转与极向磁场耦合，强烈表示了磁扭转不不变性，这于吸积盘理论中很凸起，于试验室中亦可不雅测。总之，这两个事实引出了一个遍及的问题：太阳发机电效应是否源在近太阳外貌的不不变性。

研究组陈诉了强无力的必定证据，与存眷更深差旋层的传统模子造成光鲜对于比。简朴的阐发预计注解，近太阳外貌磁扭转不不变性更好地注释了旋转振荡的时空标准以及揣度的太阳内部磁场振幅。

开始进的数值模仿证明了这些预计，并重现了半球磁流螺旋度定律。发机电效应孕育发生在一个被充实理解的近太阳外貌征象，这有助在对于影响地球电磁根蒂根基举措措施的全磁周期以及空间气候举行正确猜测。

▲ Abstract：

The magnetic dynamo cycle of the Sun features a distinct pattern: a propagating region of sunspot emergence appears around 30° latitude and vanishes near the equator every 11?years. Moreover, longitudinal flows called torsional oscillations closely shadow sunspot migration, undoubtedly sharing a co妹妹on cause. Contrary to theories suggesting deep origins of these phenomena, helioseismology pinpoints low-latitude torsional oscillations to the outer 5–10% of the Sun, the near-surface shear layer. Within this zone, inwardly increasing differential rotation coupled with a poloidal magnetic field strongly implicates the magneto-rotational instability, prominent in accretion-disk theory and observed in laboratory experiments. Together, these two facts prompt the general question: whether the solar dynamo is possibly a near-surface instability. Here we report strong affirmative evidence in stark contrast to traditional models focusing on the deeper tachocline. Simple analytic estimates show that the near-surface magneto-rotational instability better explains the spatiotemporal scales of the torsional oscillations and inferred subsurface magnetic field amplitudes. State-of-the-art numerical simulations corroborate these estimates and reproduce hemispherical magnetic current helicity laws. The dynamo resulting from a well-understood near-surface phenomenon improves prospects for accurate predictions of full magnetic cycles and space weather, affecting the electromagnetic infrastructure of Earth.

物理学Physics

Lithium tantalate photonic integrated circuits for volume manufacturing

可量产的钽酸锂光子集成电路

▲ 作者：Chengli Wang, Zihan Li, Johann Riemensberger, Grigory Lihachev, Mikhail Churaev, Wil Kao, et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07369-1

▲ 择要：

基在铌酸锂（LiNbO3）的电-光光子集成电路（PICs）已经被证实具备高Pockels系数质料的伟大威力。这实现了互补金属-氧化物-半导体电压程度下事情的线性以及高速调制器可用在数据中央通讯、高机能计较以及AI光子加快器等运用。

然而，这类技能的工业运用遭到单片晶圆高成本以及有限晶圆尺寸的拦阻。高成本是因为于微电子范畴的伟大投资鞭策了绝缘体上硅（SOI）光子学的接纳，而于其他范畴缺少现有的高容量运用。

研究组报导了由钽酸锂（LiTaO3）制成的低损耗PIC，LiTaO3已经于贸易上用在5G射频滤波器，是以可以低成本举行可扩大的打造，而且LiTaO3具备与LiNbO3相似以至于某些环境下更优的机能。成果注解，使用基在深紫外（DUV）步进的打造工艺，LiTaO3可被蚀刻以创立低损耗（5.6 dB m-1）PIC。

他们演示了一种LiTaO3马赫-曾经德尔调制器（MZM），其半波电压-长度积为1.9 V cm，电光带宽高达40 GHz。与LiNbO3比拟，LiTaO3具备极低的双折射率，可实现所有电信频段上的高密度电路以及宽带操作。此外，该平台还撑持天生孤子微梳。该事情为低成本以及多量量的下一代光电PIC的可扩大打造摊平了门路。

▲ Abstract：

Electro-optical photonic integrated circuits (PICs) based on lithium niobate (LiNbO3) have demonstrated the vast capabilities of materials with a high Pockels coefficient. They enable linear and high-speed modulators operating at complementary metal–oxide–semiconductor voltage levels to be used in applications including data-centre co妹妹unications, high-performance computing and photonic accelerators for AI. However, industrial use of this technology is hindered by the high cost per wafer and the limited wafer size. The high cost results from the lack of existing high-volume applications in other domains of the sort that accelerated the adoption of silicon-on-insulator (SOI) photonics, which was driven by vast investment in microelectronics. Here we report low-loss PICs made of lithium tantalate (LiTaO3), a material that has already been adopted co妹妹ercially for 5G radiofrequency filters and therefore enables scalable manufacturing at low cost, and it has equal, and in some cases superior, properties to LiNbO3. We show that LiTaO3 can be etched to create low-loss (5.6 dB m-1) PICs using a deep ultraviolet (DUV) stepper-based manufacturing process. We demonstrate a LiTaO3 Mach–Zehnder modulator (MZM) with a half-wave voltage–length product of 1.9 V cm and an electro-optic bandwidth of up to 40 GHz. In comparison with LiNbO3, LiTaO3 exhibits a much lower birefringence, enabling high-density circuits and broadband operation over all teleco妹妹unication bands. Moreover, the platform supports the generation of soliton microcombs. Our work paves the way for the scalable manufacture of low-cost and large-volume next-generation electro-optical PICs.

质料科学Materials Science

Selenium-alloyed tellurium oxide for amorphous p-channel transistors

硒合金氧化碲助力非晶p沟道晶体管

▲ 作者：Ao Liu, Yong-Sung Kim, Min Gyu Kim, Youjin Reo, Taoyu Zou, Taesu Choi, et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07360-w

▲ 择要：

与多晶半导体比拟，非晶半导体提供了固有成本效益，易在加工以及同一打造。传统的非晶氢化硅于电机能方面存于有余，亟需开发新质料。

高迁徙率非晶n型金属氧化物（如a-InGaZnO）的孕育发生及其与薄膜晶体管（TFTs）的集成，鞭策了现代年夜面积电子器件以及新一代显示器的前进。然而，寻觅近似的p型对于应物颇具应战，拦阻了互补金属-氧化物-半导体技能以及集成电路的进展。

研究组先容了一种非晶p型半导体的开创性设计计谋，将高迁徙率碲引入至非晶亚氧化碲基体，并展示了其于高机能、不变的p沟道TFTs以及互补电路中的运用。理论阐发展现了具备浅受主态的碲5p带的离域价带，可实现过多的空穴掺杂以及输运。

硒合金化按捺了空穴浓度，促成了p轨道的毗连，实现了高机能的p沟道TFTs，其平均场效应空穴迁徙率约为15 cm2 V-1 s-1，开/关电流比为106~107，且于偏置应力以及情况老化下具备晶圆级匀称性以及持久不变性。这项研究代表了以低成本以及工业兼容的体式格局成立贸易上可行的非晶p沟道TFT技能以及互补电子装备的要害一步。

▲ Abstract：

Compared to polycrystalline semiconductors, amorphous semiconductors offer inherent cost-effective, simple and uniform manufacturing. Traditional amorphous hydrogenated Si falls short in electrical properties, necessitating the exploration of new materials. The creation of high-mobility amorphous n-type metal oxides, such as a-InGaZnO, and their integration into thin-film transistors (TFTs) have propelled advancements in modern large-area electronics and new-generation displays. However, finding comparable p-type counterparts poses notable challenges, impeding the progress of complementary metal–oxide–semiconductor technology and integrated circuits. Here we introduce a pioneering design strategy for amorphous p-type semiconductors, incorporating high-mobility tellurium within an amorphous tellurium suboxide matrix, and demonstrate its use in high-performance, stable p-channel TFTs and complementary circuits. Theoretical analysis unveils a delocalized valence band from tellurium 5p bands with shallow acceptor states, enabling excess hole doping and transport. Selenium alloying suppresses hole concentrations and facilitates the p-orbital connectivity, realizing high-performance p-channel TFTs with an average field-effect hole mobility of around 15?ccm2 V-1 s-1 and on/off current ratios of 106~107, along with wafer-scale uniformity and long-term stabilities under bias stress and ambient ageing. This study represents a crucial stride towards establishing co妹妹ercially viable amorphous p-channel TFT technology and complementary electronics in a low-cost and industry-compatible manner.

电子项目Electronic Engineering

Full-colour 3D holographic augmented-reality displays with metasurface waveguides

具备超外貌波导的全彩3D全息加强实际显示器

▲ 作者：Manu Gopakumar, Gun-Yeal Lee, Suyeon Choi, Brian Chao, Yifan Peng, Jonghyun Kim, et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07386-0

▲ 择要：

新兴空间计较体系将数字信息无缝叠加于用户不雅察到的物理情况上，从而实现了文娱、教诲、通讯以及培训等各个范畴的厘革性体验。然而，因为加强实际（AR）显示器的光引擎投影光学元件体积重大，且没法正确描绘虚拟内容的三维（3D）深度旌旗灯号等要素，其广泛接纳遭到限定。

研究组先容了一种全息AR体系，使用反向设计的全彩色B超外貌光栅、紧凑的色散赔偿波导几何布局以及人工智能驱动的全息算法的怪异组合来降服这些应战。这些元件是协同设计的，消弭了空间光调制器以及波导之间对于重大准直光学器件的需求，并以紧凑装备规格来出现活泼的全彩3D AR内容。

为了经由过程该原型提供史无前例的视觉品质，研究组开发了一种交融物理切确的波导模子与相机反馈主动校准的进修组件的立异图象造成模子。这类怪异的纳米光子超外貌波导以及人工智能驱动全息算法的结合设计代表了于紧凑可穿着装备中创立视觉上惹人瞩目的3D AR体验的庞大前进。

▲ Abstract：

Emerging spatial computing systems seamlessly superimpose digital information on the physical environment observed ���by a user, enabling transformative experiences across various domains, such as entertainment, education, co妹妹unication and training. However, the widespread adoption of augmented-reality (AR) displays has been limited due to the bulky projection optics of their light engines and their inability to accurately portray three-dimensional (3D) depth cues for virtual content, among other factors. Here we introduce a holographic AR system that overcomes these challenges using a unique combination of inverse-designed full-colour metasurface gratings, a compact dispersion-compensating waveguide geometry and artificial-intelligence-driven holography algorithms. These elements are co-designed to eliminate the need for bulky collimation optics between the spatial light modulator and the waveguide and to present vibrant, full-colour, 3D AR content in a compact device form factor. To deliver unprecedented visual quality with our prototype, we develop an innovative image formation model that combines a physically accurate waveguide model with learned components that are automatically calibrated using camera feedback. Our unique co-design of a nanophotonic metasurface waveguide and artificial-intelligence-driven holographic algorithms represents a significant advancement in creating visually compelling 3D AR experiences in a compact wearable device.

化学Chemistry

Observation of a promethium complex in solution

溶液中钷共同物的不雅测

▲ 作者：Darren M. Driscoll, Frankie D. White, Subhamay Pramanik, Jeffrey D. Einkauf, Bruce Ravel, Dmytro Bykov, et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07267-6

▲ 择要：

镧系稀土金属于现代技能中遍及存于，但人们对于第61号元素钷（Pm）的化学性子知之甚少，Pm是一种高度放射性且难以靠近的镧系元素。只管Pm很主要，但其于镧系元素的试验研究中罕有触及，拦阻了人们对于所谓镧系元素紧缩征象的周全理解：这是通用化学教科书中援用元素周期表的一个基本方面。

研究组证实了经由过程新合成的无机二甘醇酰胺配体于水溶液中可与147Pm放射性核素（半衰期为2.62年）不变螯合。哄骗同步X射线接收光谱以及量子化学计较，研究了所获得的均配型PmIII共同物，确定了钷的配位布局以及键距。这些基本见解令人们可以或许对于一整套同构镧系元素共同物举行完备的布局研究，终极仅于试验不雅察的根蒂根基上捕捉溶液中的镧系紧缩。

研究成果注解，于镧系元素系列最先时键缩短加快，这与二甘醇酰胺显示的分散趋向有关。于水情况中对于放射性PmIII共同物的表征加深了人们对于镧系元素内部举动和f区元素化学以及分散的理解。

▲ Abstract：

Lanthanide rare-earth metals are ubiquitous in modern technologies, but we know little about chemistry of the 61st element, promethium (Pm), a lanthanide that is highly radioactive and inaccessible. Despite its importance, Pm has been conspicuously absent from the experimental studies of lanthanides, impeding our full comprehension of the so-called lanthanide contraction phenomenon: a fundamental aspect of the periodic table that is quoted in general chemistry textbooks. Here we demonstrate a stable chelation of the 147Pm radionuclide (half-life of 2.62 years) in aqueous solution by the newly synthesized organic diglycolamide ligand. The resulting homoleptic PmIII complex is studied using synchrotron X-ray absorption spectroscopy and quantum chemical calculations to establish the coordination structure and a bond distance of promethium. These fundamental insights allow a complete structural investigation of a full set of isostructural lanthanide complexes, ultimately capturing the lanthanide contraction in solution solely on the basis of experimental observations. Our results show accelerated shortening of bonds at the beginning of the lanthanide series, which can be correlated to the separation trends shown by diglycolamides. The characterization of the radioactive PmIII complex in an aqueous environment deepens our understanding of intra-lanthanide behaviour and the chemistry and separation of the f-block elements.

Boron catalysis in a designer enzyme

人工酶中的硼催化作用

▲ 作者：Lars Longwitz, Reuben B. Leveson-Gower, Henri?tte J. Rozeboom, Andy-Mark W. H. Thunnissen Gerard Roelfes

▲ 链接：

https://www.nature.com/articles/s41586-024-07391-3

▲ 择要：

酶于提高化工出产的敌对性以及效率方面阐扬着愈来愈主要的作用，但因为酶的反映机理规模相对于狭小，其运用的多样性严峻掉队在化学催化剂。含有非生物功效酶的创举促成了天然界经典以外的反映机制，并为彻底可编程的生物催化摊平了门路。

研究组提出了一种彻底遗传编码的含硼酸的人工酶，其无机催化活性是自然或者项目生物催化剂没法实现的。这类硼酶经由过程肟造成催化羟基酮的动力学拆分，此中与卵白质支架的要害彼此作用有助在催化。定向进化运动致使了对于几种差别底物具备自然酶样对于映体选择性的变体。

哄骗X射线晶体学、高分辩率质谱（HRMS）以及11B NMR波谱证明了硼酶的怪异活化模式。研究成果注解，遗传暗码扩大可用在创立可进化的对于映选择性酶，这些酶依靠在外源性催化部门，如硼酸以及经由过程自然某人工酶的催化稠浊性没法到达的通路反映机制。

▲ Abstract：

Enzymes play an increasingly important role in improving the benignity and efficiency of chemical production, yet the diversity of their applications lags heavily behind chemical catalysts as a result of the relatively narrow range of reaction mechanisms of enzymes. The creation of enzymes containing non-biological functionalities facilitates reaction mechanisms outside nature’s canon and paves the way towards fully progra妹妹able biocatalysis. Here we present a completely genetically encoded boronic-acid-containing designer enzyme with organocatalytic reactivity not achievable with natural or engineered biocatalysts. This boron enzyme catalyses the kinetic resolution of hydroxyketones by oxime formation, in which crucial interactions with the protein scaffold assist in the catalysis. A directed evolution campaign led to a variant with natural-enzyme-like enantioselectivities for several different substrates. The unique activation mode of the boron enzyme was confirmed using X-ray crystallography, high-resolution mass spectrometry (HRMS) and 11B NMR spectroscopy. Our study demonstrates that genetic-code expansion can be used to create evolvable enantioselective enzymes that rely on xenobiotic catalytic moieties such as boronic acids and access reaction mechanisms not reachable through catalytic promiscuity of natural or engineered enzymes.

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