▲ 作者：Takuya Shimajiri, Soki Kawaguchi, Takanori Suzuki & Yusuke Ishigaki

▲ 链接：

https://www.nature.com/articles/s41586-024-07965-1

▲ 摘要：

在此，我们报告用具有细长C-C单键的烃的单电子氧化法分离碳原子间单电子σ键的化合物。通过单晶x射线衍射分析和拉曼光谱分析证实了100 K时C-C单电子σ键（2.921(3)?）的存在，并通过密度泛函理论计算证实了该键的存在。

本文的结果明确地证明了近一个世纪前假设的C-C单电子σ键的存在，从而可以期望通过探索成键和非成键状态之间的边界，为进一步发展化学的不同领域铺平道路。

▲ Abstract：

Here we report the isolation of a compound with a one-electron σ-bond between carbon atoms by means of the one-electron oxidation of a hydrocarbon with an elongated C–C single bond. The presence of the C·C one-electron σ-bond (2.921(3)?? at 100?K) was confirmed experimentally by single-crystal X-ray diffraction analysis and Raman spectroscopy, and theoretically by density functional theory calculations. The results of this paper unequivocally demonstrate the existence of a C·C one-electron σ-bond, which was postulated nearly a century ago, and can thus be expected to pave the way for further development in different areas of chemistry by probing the boundary between bonded and non-bonded states.

▲ 作者：Xin Gu, Yu-An Zhang et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07988-8

▲ 摘要：

在此，我们公开了一种将脂肪族氨基酸转化为结构多样的类似物的逐步脱氢方法。该方法成功的关键在于开发了一种由光化学照射驱动的选择性催化无受体脱氢方法，为下游功能化提供了末端烯烃中间体的途径。

总的来说，这种策略能够快速合成新的氨基酸构建块，并为后期修饰更复杂的寡肽提供了可能性。

▲ Abstract：

Here we disclose a stepwise dehydrogenative method to convert aliphatic amino acids into structurally diverse analogues. The key to the success of this approach lies in the development of a selective catalytic acceptorless dehydrogenation method driven by photochemical irradiation, which provides access to terminal alkene intermediates for downstream functionalization. Overall, this strategy enables the rapid synthesis of new amino acid building blocks and suggests possibilities for the late-stage modification of more complex oligopeptides.

材料科学Material Sciences

▲ 作者：Len van Deurzen, Eungkyun Kim et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07983-z

▲ 摘要：

在这项研究中，我们引入了双电子学，表明在同一半导体晶圆的阳离子面上制造光子器件和阴离子面上制造电子器件是可能的。

这带来了在单一结构中利用极性半导体的两面的可能性，其中电子、光子和声学特性可以在同一晶圆的相对面上实现，显著增强了这种革命性半导体家族的功能。

▲ Abstract：

In this work, we introduce dualtronics, showing that it is possible to make photonic devices on the cation face and electronic devices on the anion face of the same semiconductor wafer. This opens the possibility for making use of both faces of polar semiconductors in a single structure, in which electronic, photonic and acoustic properties can be implemented on opposite faces of the same wafer, markedly enhancing the functional capabilities of this revolutionary semiconductor family.

物理学Physics

▲ 作者：Alec Cao, William J. Eckner et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07913-z

▲ 摘要：

在此，我们开发并使用一系列多量子位里德堡门来生成Greenberger–Horne–Zeilinger（GHZ）类型的薛定谔猫状态，在可编程原子阵列中具有多达9个光时钟量子位。在足够短的黑暗时间下的原子激光比较中，我们使用最多四个量子比特的GHZ状态证明了低于标准量子极限（SQL）的分数频率不稳定性。

然而，由于它们的动态范围变小，单一尺寸的GHZ态与未纠缠的原子相比在最佳暗时无法提高可实现的时钟精度。为了克服这一障碍，我们同时准备了一个不同大小的GHZ状态级联，以便在延长的间隔内进行无歧义的相位估计。这些结果展示了接近海森堡有限尺度的光学原子钟精度的关键组成部分。

▲ Abstract：

Here we develop and use a family of multi-qubit Rydberg gates to generate Schr?dinger cat states of the Greenberger–Horne–Zeilinger (GHZ) type with up to nine optical clock qubits in a programmable atom array. In an atom-laser comparison at sufficiently short dark times, we demonstrate a fractional frequency instability below the standard quantum limit (SQL) using GHZ states of up to four qubits. However, because of their reduced dynamic range, GHZ states of a single size fail to improve the achievable clock precision at the optimal dark time compared with unentangled atoms. Towards overcoming this hurdle, we simultaneously prepare a cascade of varying-size GHZ states to perform unambiguous phase estimation over an extended interval. These results demonstrate key building blocks for approaching Heisenberg-limited scaling of optical atomic clock precision.

地球科学Earth Science

▲ 作者：Emily C. Geyman, Madison M. Douglas et al.

▲ 链接：

https://www.nature.com/articles/s41586-024-07978-w

▲ 摘要：

在此，我们开发了新的计算方法，可以在比卫星图像像素尺寸小5—10倍的长度尺度上检测河岸侵蚀情况。这一创新使得在河流经历水温和流量最大变化的次月时间尺度上量化侵蚀变成可能。

我们使用这些高频观测来约束河岸侵蚀在多大程度上受到热条件限制的程度——这一要求将在永久冻土融化时消失——并与有足够水流以运输构成河岸的沉积物的力学条件进行对比，后者是所有河流都会经历的情况。对阿拉斯加科尤库克河高分辨率数据的分析表明，永久冻土的存在使侵蚀率降低了47%。

通过我们的观测，我们校准并验证了一个可以应用于不同北极河流的数值模型。该模型预测，永久冻土完全融化可能导致北极河流的迁移率增加30%至100%。

▲ Abstract：

Here we develop new computational methods that enable the detection of riverbank erosion at length scales 5–10 times smaller than the pixel size in satellite imagery, an innovation that unlocks the ability to quantify erosion at the sub-monthly timescales when rivers undergo their largest variations in water temperature and flow. We use these high-frequency observations to constrain the extent to which erosion is limited by the thermal condition of melting the pore ice that cements bank sediment, a requirement that will disappear when permafrost thaws, versus the mechanical condition of having sufficient flow to transport the sediment comprising the riverbanks, a condition experienced by all rivers. Analysis of high-resolution data from the Koyukuk River, Alaska, shows that the presence of permafrost reduces erosion rates by 47%. Using our observations, we calibrate and validate a numerical model that can be applied to diverse Arctic rivers. The model predicts that full permafrost thaw may lead to a 30–100% increase in the migration rates of Arctic rivers.