作者:冯维维 来源:科学网微信公众号 发布时间:2024/5/11 20:36:39
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《自然》(20240509出版)一周论文导读

 

编译 | 冯维维

Nature, 9 May 2024, Volume 629 Issue 8011

《自然》2024年5月9日,第629卷,8011期

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物理学Physics

Venus water loss is dominated by HCO+ dissociative recombination

金星失水主要是由HCO+解离复合引起的

▲ 作者:M. S. Chaffin, E. M. Cangi, B. S. Gregory, R. V. Yelle, J. Deighan, R. D. Elliott & H. Gr?ller

▲ 链接:

https://www.nature.com/articles/s41586-024-07261-y

▲ 摘要:

尽管金星的大小和物质来源与地球相似,但它极其干燥,这表明几乎所有的水都是通过氢气从古老的蒸汽为主的大气中流出而流失到太空中的。这种流体动力学逃逸很可能移除了最初类似地球的3公里全球等效层(GEL)的大部分水,但不能将大气消耗到目前观测到的3厘米的GEL,因为它在大约10~100米的GEL以下关闭。

为了使金星上的水完全流失,并使观测到的大量大气中氘的富集量达到地球的120倍,需要有至今仍在运行的非热氢逸出机制。早期的研究将这些因素确定为共振电荷交换、热氧冲击和离子流出,建立了氢逸出的共识观点,此后只有很少的更新。

我们的研究表明这一共识忽略了最重要的现今氢损失过程,HCO+解离重组。这一过程几乎使金星H的逃逸率增加了1倍,因此,维持稳定的大气水丰度所需的火山水排放和/或撞击物的数量也增加了1倍。

这些较高的损失率解决了在同时解释金星水的测量丰度和同位素比率方面长期存在的困难,并将在推测的晚期海洋情景之后加速干燥。由于设计上的限制,过去的金星任务无法同时测量HCO+和由其重组产生的逃逸氢,未来的航天器测量是必要的。

▲ Abstract:

Despite its Earth-like size and source material, Venus is extremely dry, indicating near-total water loss to space by means of hydrogen outflow from an ancient, steam-dominated atmosphere. Such hydrodynamic escape likely removed most of an initial Earth-like 3-km global equivalent layer (GEL) of water but cannot deplete the atmosphere to the observed 3-cm GEL because it shuts down below about 10–100?m GEL. To complete Venus water loss, and to produce the observed bulk atmospheric enrichment in deuterium of about 120?times Earth, nonthermal H escape mechanisms still operating today are required. Early studies identified these as resonant charge exchange, hot oxygen impact and ion outflow, establishing a consensus view of H escape that has since received only minimal updates. Here we show that this consensus omits the most important present-day H loss process, HCO+ dissociative recombination. This process nearly doubles the Venus H escape rate and, consequently, doubles the amount of present-day volcanic water outgassing and/or impactor infall required to maintain a steady-state atmospheric water abundance. These higher loss rates resolve long-standing difficulties in simultaneously explaining the measured abundance and isotope ratio of Venusian water and would enable faster desiccation in the wake of speculative late ocean scenarios. Design limitations prevented past Venus missions from measuring both HCO+ and the escaping hydrogen produced by its recombination; future spacecraft measurements are imperative.

An atomic boson sampler

原子玻色子采样器

▲ 作者:Aaron W. Young, Shawn Geller, William J. Eckner, Nathan Schine, Scott Glancy, Emanuel Knill & Adam M. Kaufman

▲ 链接:

https://www.nature.com/articles/s41586-024-07304-4

▲ 摘要:

玻色子采样器实现了量子计算的受限模型。它是由根据可编程的、非相互作用的动力学传播的相同玻色子的干涉所产生的分布的采样能力来定义的。有效的精确的经典玻色子采样模拟被认为是不存在的,这激发了光子越来越多的光子学中突破性的玻色子采样实验。

然而,很难产生和可靠地进化特定数量的低损耗光子,因此通常使用概率技术进行后选择或标记改变标准玻色子采样。

我们通过在二维隧道耦合光学晶格中使用超冷原子实现玻色子采样来解决上述挑战。这一演示是由一种以前未实现的工具组合实现的,包括高保真光学冷却和晶格中原子的成像,以及使用光学镊子对这些原子进行可编程控制。当扩展到相互作用系统时,我们的研究证明了在各种哈伯德模型的模拟中直接组装基态和激发态所需的核心能力。

▲ Abstract:

A boson sampler implements a restricted model of quantum computing. It is defined by the ability to sample from the distribution resulting from the interference of identical bosons propagating according to programmable, non-interacting dynamics. An efficient exact classical simulation of boson sampling is not believed to exist, which has motivated ground-breaking boson sampling experiments in photonics with increasingly many photons. However, it is difficult to generate and reliably evolve specific numbers of photons with low loss, and thus probabilistic techniques for postselection or marked changes to standard boson sampling are generally used. Here, we address the above challenges by implementing boson sampling using ultracold atoms in a two-dimensional, tunnel-coupled optical lattice. This demonstration is enabled by a previously unrealized combination of tools involving high-fidelity optical cooling and imaging of atoms in a lattice, as well as programmable control of those atoms using optical tweezers. When extended to interacting systems, our work demonstrates the core abilities required to directly assemble ground and excited states in simulations of various Hubbard models.

Observation of Nagaoka polarons in a Fermi–Hubbard quantum simulator

费米—哈伯德量子模拟器中长冈极化子的观测

▲ 作者:Martin Lebrat, Muqing Xu, Lev Haldar Kendrick, Anant Kale, Youqi Gang, Pranav Seetharaman, Ivan Morera, Ehsan Khatami, Eugene Demler和Markus Greiner

▲ 链接:

https://www.nature.com/articles/s41586-024-07272-9

▲ 摘要:

量子干涉可以深刻地改变物质的多体相的性质。在哈伯德模型中,长冈证明了引入单个流动电荷可以通过路径干扰将顺磁绝缘体转变为铁磁体。然而,由单独成像的掺杂剂引起的这种动力学磁性的微观观察迄今为止还难以捉摸。我们证明了长冈极化子在一个三角形光学晶格中用强相互作用费米子实现的哈伯德系统中的出现。

利用量子气体显微镜,我们将这些极化子成像为粒子掺杂剂周围的扩展铁磁气泡,这些气泡是由相干掺杂剂运动和自旋交换的局部相互作用产生的。

相比之下,由于三角形几何结构引起的动力学挫折促进了空穴掺杂剂周围的反铁磁极化子。我们的工作预示着探索由强相关系统和超大尺寸的电荷运动驱动的奇异量子相,这对数值模拟具有挑战性。

▲ Abstract:

Quantum interference can deeply alter the nature of many-body phases of matter. In the case of the Hubbard model, Nagaoka proved that introducing a single itinerant charge can transform a paramagnetic insulator into a ferromagnet through path interference. However, a microscopic observation of this kinetic magnetism induced by individually imaged dopants has been so far elusive. Here we demonstrate the emergence of Nagaoka polarons in a Hubbard system realized with strongly interacting fermions in a triangular optical lattice. Using quantum gas microscopy, we image these polarons as extended ferromagnetic bubbles around particle dopants arising from the local interplay of coherent dopant motion and spin exchange. By contrast, kinetic frustration due to the triangular geometry promotes antiferromagnetic polarons around hole dopants. Our work augurs the exploration of exotic quantum phases driven by charge motion in strongly correlated systems and over sizes that are challenging for numerical simulation.

化学Chemistry

Multi-project wafers for flexible thin-film electronics by independent foundries

由独立代工厂生产的柔性薄膜电子产品的多项目晶圆

▲ 作者:Hikmet ?eliker, Wim Dehaene & Kris Myny

▲ 链接:

https://www.nature.com/articles/s41586-024-07306-2

▲ 摘要:

柔性和大面积电子产品依靠薄膜晶体管(TFT)来制造显示器、大面积图像传感器、微处理器、可穿戴医疗贴片、数字微流体等。虽然硅基互补金属氧化物半导体(CMOS)芯片是在一个晶圆上使用多个芯片制造的,而且多项目晶圆概念可以在同一个晶圆内聚集各种CMOS芯片设计,但TFT制造目前缺乏一种完全验证的通用设计方法。

这增加了制造基于TFT的柔性电子产品的成本和复杂性,减缓了它们与更成熟应用的集成,并限制了代工厂可实现的设计复杂性。

我们展示了一个稳定的、高产量的TFT平台,用于两种主流TFT技术的无晶圆制造,即基于晶圆的非晶铟镓锌氧化物和基于面板的低温多晶硅,这两种关键的TFT技术适用于柔性衬底。

我们在这两种技术中设计了标志性的6502微处理器,作为演示和扩展多项目晶圆方法的用例。启用TFT的代工模型,作为硅CMOS技术的类比,可以加速基于这些器件的应用和技术的增长和发展。

▲ Abstract:

Flexible and large-area electronics rely on thin-film transistors (TFTs) to make displays, large-area image sensors, microprocessors, wearable healthcare patches, digital microfluidics and more. Although silicon-based complementary metal–oxide–semiconductor (CMOS) chips are manufactured using several dies on a single wafer and the multi-project wafer concept enables the aggregation of various CMOS chip designs within the same die, TFT fabrication is currently lacking a fully verified, universal design approach. This increases the cost and complexity of manufacturing TFT-based flexible electronics, slowing down their integration into more mature applications and limiting the design complexity achievable by foundries. Here we show a stable and high-yield TFT platform for the fabless manufacturing of two mainstream TFT technologies, wafer-based amorphous indium–gallium–zinc oxide and panel-based low-temperature polycrystalline silicon, two key TFT technologies applicable to flexible substrates. We have designed the iconic 6502 microprocessor in both technologies as a use case to demonstrate and expand the multi-project wafer approach. Enabling the foundry model for TFTs, as an analogy of silicon CMOS technologies, can accelerate the growth and development of applications and technologies based on these devices.

Chemical short-range disorder in lithium oxide cathodes

锂氧化物阴极的化学短程失序

▲ 作者:Qidi Wang, Zhenpeng Yao, Jianlin Wang, Hao Guo, Chao Li, Dong Zhou, Xuedong Bai, Hong Li, Baohua Li, Marnix Wagemaker & Chenglong Zhao

▲ 链接:

https://www.nature.com/articles/s41586-024-07362-8

▲ 摘要:

有序层状结构是锂离子阴极的重要组成部分。然而,在充电时,固有的脆弱的缺锂框架容易受到晶格应变和结构和/或化学机械退化的影响,导致容量迅速退化,从而缩短电池寿命。

我们报告了一种解决这些问题的方法,该方法使用化学短程无序(CSRD)集成到氧化物阴极中,该方法涉及晶格中元素在空间维度上的局部分布,跨越几个最近邻的间隔。这是在结构化学基本原理的指导下,通过改进的陶瓷合成工艺实现的。

为了证明其可行性,我们展示了CSRD的引入如何实质性地影响层状锂钴氧化物阴极的晶体结构。这表现在过渡金属环境及其与氧的相互作用中,有效地防止了晶体板在除锂过程中的有害滑动和结构恶化。同时影响电子结构,提高电子导电性。这些特性对锂离子存储能力非常有利,显著提高了循环寿命和倍率能力。

此外,我们发现CSRD可以通过改进的化学共掺杂引入到其他层状氧化物材料中,进一步说明了其提高结构和电化学稳定性的潜力。这些发现为氧化物阴极的设计开辟了新的途径,为CSRD对先进功能材料的晶体和电子结构的影响提供了见解。

▲ Abstract:

Ordered layered structures serve as essential components in lithium (Li)-ion cathodes1,2,3. However, on charging, the inherently delicate Li-deficient frameworks become vulnerable to lattice strain and structural and/or chemo-mechanical degradation, resulting in rapid capacity deterioration and thus short battery life2,4. Here we report an approach that addresses these issues using the integration of chemical short-range disorder (CSRD) into oxide cathodes, which involves the localized distribution of elements in a crystalline lattice over spatial dimensions, spanning a few nearest-neighbour spacings. This is guided by fundamental principles of structural chemistry and achieved through an improved ceramic synthesis process. To demonstrate its viability, we showcase how the introduction of CSRD substantially affects the crystal structure of layered Li cobalt oxide cathodes. This is manifested in the transition metal environment and its interactions with oxygen, effectively preventing detrimental sliding of crystal slabs and structural deterioration during Li removal. Meanwhile, it affects the electronic structure, leading to improved electronic conductivity. These attributes are highly beneficial for Li-ion storage capabilities, markedly improving cycle life and rate capability. Moreover, we find that CSRD can be introduced in additional layered oxide materials through improved chemical co-doping, further illustrating its potential to enhance structural and electrochemical stability. These findings open up new avenues for the design of oxide cathodes, offering insights into the effects of CSRD on the crystal and electronic structure of advanced functional materials.

Growth of diamond in liquid metal at 1 atm pressure

金刚石在1atm压力下在液态金属中的生长

▲ 作者:Yan Gong, Da Luo, Myeonggi Choe, Yongchul Kim, Babu Ram, Mohammad Zafari, Won Kyung Seong, Pavel Bakharev, Meihui Wang, In Kee Park, Seulyi Lee, Tae Joo Shin, Zonghoon Lee, Geunsik Lee & Rodney S. Ruoff

▲ 链接:

https://www.nature.com/articles/s41586-024-07339-7

▲ 摘要:

天然钻石是在几十亿年前地球上地幔的金属熔体中形成的,温度为900~ 1400°C,压力为5—6 GPa。根据碳3的相图,金刚石在高压和高温条件下是热力学稳定的。

1955年,通用电气公司的科学家们发明并使用了高压高温设备,利用约7gpa和1600°C的硫化铁熔融来合成钻石。有一种现有的模型认为,金刚石只能在高压和高温下用液态金属生长。我们描述了使用液态金属在1atm压力和1025°C下生长无种子颗粒的金刚石晶体和多晶金刚石薄膜,打破了这种模式。

金刚石生长在由镓、铁、镍和硅组成的液态金属的地下,是通过甲烷的催化活化和碳原子向地下区域内扩散而形成的。我们发现碳在液态金属亚表面的过饱和导致了金刚石的成核和生长,其中Si在稳定四价键碳簇中起着重要的作用,而四价键碳簇在成核中起着重要的作用。

在中等温度和1atm压力下在液态金属中生长(亚稳态)金刚石,为进一步的基础科学研究和这种生长的尺度化开辟了许多可能性。

▲ Abstract:

Natural diamonds were (and are) formed (thousands of million years ago) in the upper mantle of Earth in metallic melts at temperatures of 900–1,400?°C and at pressures of 5–6?GPa (refs.?1,2). Diamond is thermodynamically stable under high-pressure and high-temperature conditions as per the phase diagram of carbon3. Scientists at General Electric invented and used a high-pressure and high-temperature apparatus in 1955 to synthesize diamonds by using molten iron sulfide at about 7?GPa and 1,600?°C (refs.?4,5,6). There is an existing model that diamond can be grown using liquid metals only at both high pressure and high temperature7. Here we describe the growth of diamond crystals and polycrystalline diamond films with no seed particles using liquid metal but at 1?atm pressure and at 1,025?°C, breaking this pattern. Diamond grew in the subsurface of liquid metal composed of gallium, iron, nickel and silicon, by catalytic activation of methane and diffusion of carbon atoms into and within the subsurface regions. We found that the supersaturation of carbon in the liquid metal subsurface leads to the nucleation and growth of diamonds, with Si playing an important part in stabilizing tetravalently bonded carbon clusters that play a part in nucleation. Growth of (metastable) diamond in liquid metal at moderate temperature and 1?atm pressure opens many possibilities for further basic science studies and for the scaling of this type of growth.

 
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