Science, 31 MAY 2024, VOL 384, ISSUE 6699

《科学》2024年5月31日，第384卷，6699期

?

质料科学Materials Science

Molecular templating of layered halide perovskite nanowires

层状卤化物钙钛矿纳米线的份子模板

▲ 作者：WENHAO SHAO, JEONG HUI KIM, JEFFREY SIMON, ZHICHEN NIAN, SUNG-DOO BAEK, YUAN LU, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adl0920

▲ 择要：

层状金属卤化物钙钛矿或者二维钙钛矿可以于溶液中合成，并可经由过程转变构成来调治其光学以及电子性子。

研究组报导了一种份子模板要领，限定了沿除了[110]之外所有晶体标的目的的晶体生长，从而促成了一维生长。该要领广泛合用在合成一系列具备年夜纵横比以及可调无机-有机化学构成的高品质层状钙钛矿纳米线。

这些纳米线造成了很是清楚以及矫捷的空腔，体现出逾越传统钙钛矿纳米线的一系列差别平常的光学特征。研究组不雅察到各向同性发射偏振、低损耗波导（低在3分贝/毫米）以及有用的低阈值光放年夜（低在20微焦耳/平方厘米）。

▲ Abstract：

Layered metal-halide perovskites, or two-dimensional perovskites, can be synthesized in solution, and their optical and electronic properties can be tuned by changing their composition. We report a molecular templating method that restricted crystal growth along all crystallographic directions except for [110] and promoted one-dimensional growth. Our approach is widely applicable to synthesize a range of high-quality layered perovskite nanowires with large aspect ratios and tunable organic-inorganic chemical compositions. These nanowires form exceptionally well-defined and flexible cavities that exhibited a wide range of unusual optical properties beyond those of conventional perovskite nanowires. We observed anisotropic emission polarization, low-loss waveguiding (below 3 decibels per millimeter), and efficient low-threshold light amplification (below 20 microjoules per square centimeter).

A three-dimensionally architected electronic skin mimicking human mechanosensation

模仿人类机械感知的三维布局电子皮肤

▲ 作者：ZHI LIU, XIAONAN HU, RENHENG BO, YOUZHOU YANG, XU CHENG, WENBO PANG, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adk5556

▲ 择要：

人体皮肤对于机械刺激的感知源在将外力转化为电旌旗灯号的机械感触感染器的传导。虽然模拟这些机械感触感染器的空间漫衍可以使电子皮肤的成长可以或许解耦传感法向力/剪切力以及应变，但其仍难以捉摸。

研究组报导了一种三维（3D）布局的电子皮肤（称为3DAE皮肤），其力以及应变传感组件以3D结构摆列，模拟人类皮肤中的默克尔细胞以及鲁菲尼氏小体。

这类3DAE皮肤具备优秀的法向力、剪切力以及应变解耦传感机能，可用在开发触觉体系，经由过程触摸同时丈量物体的模量/曲率。演示包孕对于各类外形以及鲜嫩度的生果、面包以及蛋糕举行倏地模量丈量。

▲ Abstract：

Human skin sensing of mechanical stimuli originates from transduction of mechanoreceptors that converts external forces into electrical signals. Although imitating the spatial distribution of those mechanoreceptors can enable developments of electronic skins capable of decoupled sensing of normal/shear forces and strains, it remains elusive. We report a three-dimensionally (3D) architected electronic skin (denoted as 3DAE-Skin) with force and strain sensing components arranged in a 3D layout that mimics that of Merkel cells and Ruffini endings in human skin. This 3DAE-Skin shows excellent decoupled sensing performances of normal force, shear force, and strain and enables development of a tactile system for simultaneous modulus/curvature measurements of an object through touch. Demonstrations include rapid modulus measurements of fruits, bread, and cake with various shapes and degrees of freshness.

Spontaneous weathering of natural minerals in charged water microdroplets forms nanomaterials

自然矿物资于带电水微滴中天然风化造成纳米质料

▲ 作者：B. K. SPOORTHI, KOYENDRILA DEBNATH, PALLAB BASURI, ANKIT NAGAR, UMESH V. WAGHMARE AND THALAPPIL PRADEEP

▲ 链接：

https://www.science.org/doi/10.1126/science.adl3364

▲ 择要：

于这项事情中，研究组展示了常见矿物资颗粒于几毫秒内自觉分化，于带电的水微滴中造成纳米颗粒。他们将石英以及红宝石等微米级自然矿物整合到经由过程电喷雾孕育发生的水性微滴中，将其转化为5至10纳米的颗粒。将液滴沉积于基底上，从而实现纳米颗粒表征。

研究组经由过程模仿确定，石英履历了质子引诱滑移，出格是当尺寸缩小并袒露于电场中时。这致使颗粒破裂以及硅酸盐碎片的造成，质谱阐发证明了这一点。思量到年夜气中带电气溶胶的遍及存于，这类倏地风化历程可能对于泥土造成至关主要。

▲ Abstract：

In this work, we show that particles of co妹妹on minerals break down spontaneously to form nanoparticles in charged water microdroplets within milliseconds. We transformed micron-sized natural minerals like quartz and ruby into 5- to 10-nanometer particles when integrated into aqueous microdroplets generated via electrospray. We deposited the droplets on a substrate, which allowed nanoparticle characterization. We determined through simulations that quartz undergoes proton-induced slip, especially when reduced in size and exposed to an electric field. This leads to particle scission and the formation of silicate fragments, which we confirmed with mass spectrometry. This rapid weathering process may be important for soil formation, given the prevalence of charged aerosols in the atmosphere.

Shearing brittle intermetallics enhances cryogenic strength and ductility of steels

剪切脆性金属间化合物提高钢的低温强度以及塑性

▲ 作者：FENG WANG, MIAO SONG, MOHAMED N. ELKOT, NING YAO, BINHAN SUN, MIN SONG, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.ado2919

▲ 择要：

沉淀物对于在打造机械强度高的金属质料至关主要。于这项事情中，研究组报导了B2相（有序体心立方）纳米沉淀（凡是被以为是不成剪切的金属间化合物）于低温拉伸载荷历程中于轻质复合钢中的位错切割。

因为亚纳米标准局部化学有序区的显著强化以及基体中多主元素较着的固溶强化，奥氏体基体中位错滑移的高强度程度实现了剪切。这类机制不只哄骗了原本难以穿透的脆性纳米沉淀物所提供的强烈强化以及应变软化，并且还经由过程其持续剪切以及连续变形引入了塑性。

是以，这类钢材展示了超高的低温拉伸强度，高达2吉帕，拉伸伸长率到达34%。这项研究展现了一种设计高机能布局质料的新计谋。

▲ Abstract：

Precipitates are crucial for crafting mechanically strong metallic materials. In this work, we report the dislocation cutting of B2 (ordered body-centered cubic) nanoprecipitates, typically considered nonshearable intermetallics, in a lightweight compositionally complex steel during cryogenic tensile loading. Shearing is enabled by the high strength level for dislocation glide within the austenitic matrix, attributed to the substantial strengthening from subnanoscale local chemical ordering zones and the pronounced solid solution strengthening from the multiprincipal elements in the matrix. This mechanism not only harnesses the intense strengthening and strain hardening provided by otherwise impenetrable brittle nanoprecipitates but also introduces ductility through their sequential shearing with ongoing deformation. Our steel thus showcases ultrahigh cryogenic tensile strength up to 2 gigapascal at a remarkable tensile elongation of 34%. This study reveals a new strategy for designing high-performance structural materials.

地球科学Earth Science

Heinrich event ice discharge and the fate of the Atlantic Meridional Overturning Circulation

海因里希事务冰排放与年夜西洋经向翻转环流的运气

▲ 作者：YUXIN ZHOU AND JERRY F. MCMANUS

▲ 链接：

https://www.science.org/doi/10.1126/science.adh8369

▲ 择要：

于海因里希事务时期，伟大的冰山“舰队”偶然沉没北年夜西洋，减弱了翻转环流。这些事务的冰排放限定了翻转环流对于冰山熔化的敏感性。

研究组重修了海因里希事务4时期的这些冰排放，发明其高达0.13 Sv（1 Sv = 100万立方米每一秒），而于所有事务中平均值仅为0.029 Sv。如今格陵兰冰盖的冰山崩解与中等范围海因里希事务相称。

跟着将来格陵兰冰盖从海洋尽头出口减退，仅冰山崩解尚有余以对于年夜西洋翻转环流形成灾害性粉碎，其可能不会连续充足长的时间，只管加快的格陵兰径流以及连续的全世界变暖仍旧威逼着环流的不变性。

▲ Abstract：

During Heinrich events, great armadas of icebergs episodically flooded the North Atlantic Ocean and weakened overturning circulation. The ice discharges of these episodes constrain the sensitivity of overturning circulation to iceberg melting. We reconstructed these ice discharges to be as high as 0.13 sverdrup (Sv) (1 Sv = 1 million cubic meters per second) during Heinrich event 4 and to average 0.029 Sv over all episodes. The present-day Greenland Ice Sheet calving of icebergs is comparable to that of a mid-range Heinrich event. As the future Greenland Ice Sheet recedes from marine-terminating outlets, its iceberg calving likely will not persist long enough for icebergs alone to cause catastrophic disruption to the Atlantic overturning circulation, although the accelerating Greenland runoff and continued global warming remain threats to the circulation stability.

社会学Sociology

Supersharers of fake news on Twitter

推特上的假新闻超等分享者

▲ 作者：SAHAR BARIBI-BARTOV, BRIONY SWIRE-THOMPSON AND NIR GRINBERG

▲ 链接：

https://www.science.org/doi/10.1126/science.adl4435

▲ 择要：

当局也许有威力让假新闻满盈社交媒体，但平凡选平易近怎样使用这些泛滥的假新闻却不为人知。

于这项事情中，研究组确定了2107名挂号的美国选平易近，2020年美国总统年夜选时期，他们于由664391名选平易近构成的整个群组中于Twitter上分享了80%的假新闻。成果发明超等分享者是该收集的主要成员，于该平台注册选平易近中占比高达5.2%。

超等分享者中女性、老年人以及注册共以及党人的比例较着太高。超等分享者的伟大流量好像并不是主动孕育发生，而是经由过程人工以及连续转发孕育发生的。这些发明凸显了社交媒体对于平易近主的懦弱性，于社交媒体上，一小群人污蔑了很多人的政治实际。

▲ Abstract：

Governments may have the capacity to flood social media with fake news, but little is known about the use of flooding by ordinary voters. In this work, we identify 2107 registered US voters who account for 80% of the fake news shared on Twitter during the 2020 US presidential election by an entire panel of 664391 voters. We found that supersharers were important members of the network, reaching a sizable 5.2% of registered voters on the platform. Supersharers had a significant overrepresentation of women, older adults, and registered Republicans. Supersharers’ massive volume did not seem automated but was rather generated through manual and persistent retweeting. These findings highlight a vulnerability of social media for democracy, where a small group of people distort the political reality for many.