《迷信》（20250221出书）一周论文导读

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编译 | 未玖Science, 21 FEB 2025, VOL 387, ISSUE 6736《迷信》2025年2月21日，第387卷，6736期?资料迷信Materials ScienceInterfacial bonding enhances thermoelectric cooling in 3D-printed materials界面联合加强了3D打印资料的热电冷却▲ 作者：SHENGDUO XU, SHARONA HORTA, ABAYOMI LAWAL, KRISHNENDU MAJI, MAGALI LORION AND MARIA IBá?EZ▲ 链接：https://www.science.org/doi/10.1126/science.ads0426▲ 择要：热电冷却器（TECs）在古代热治理中至关主要，但在效力跟制作可扩大性方面存在范围性。研讨组经由过程应用挤出式3D打印技巧来制作高机能热电资料，以处理这些挑衅。该打印墨水配方确保了3D打印构造的完全性跟烧结进程中的颗粒间无效联合，在室温下，p型碲化铋锑[(Bi,Sb)2Te3]跟n型硒化银（Ag2Se）资料的无穷纲热电优值（zT）分辨到达创记录的1.42跟1.3。所得TEC在氛围中的冷却温度梯度为50℃。别的，这种可扩大且存在本钱效益的方式绕过了高能耗跟耗时的步调（比方铸锭制备跟随后的加工进程），为热电器件出产供给了一种反动性的处理计划，预示着高效跟可连续热电技巧的新时期。▲ Abstract：Thermoelectric coolers (TECs) are pivotal in modern heat management but face limitations in efficiency and manufacturing scalability. We address these challenges by using an extrusion-based 3D printing technique to fabricate high-performance thermoelectric materials. Our ink formulations ensure the integrity of the 3D-printed structure and effective particle bonding during sintering, achieving record-high figure of merit (zT) values of 1.42 for p-type bismuth antimony telluride [(Bi,Sb)2Te3] and 1.3 for n-type silver selenide (Ag2Se) materials at room temperature. The resulting TEC demonstrates a cooling temperature gradient of 50°C in air. Moreover, this scalable and cost-effective method circumvents energy-intensive and time-consuming steps, such as ingot preparation and subsequently machining processes, offering a transformative solution for thermoelectric device production and heralding a new era of efficient and sustainable thermoelectric technologies.Magnetic modulation of keyhole instability during laser welding and additive manufacturing激光焊接跟增材制作进程中锁孔不稳固性的磁调制▲ 作者：XIANQIANG FAN, TRISTAN G. FLEMING, SAMUEL J. CLARK, KAMEL FEZZAA, ANNA C. M. GETLEY, SEBASTIAN MARUSSI, ET AL.▲ 链接：https://www.science.org/doi/10.1126/science.ado8554▲ 择要：激光焊接跟激光粉末床熔合（LPBF）进程中的锁孔不稳固会招致锁孔坍塌跟孔洞构成。应用高速X射线成像，研讨组证实了涡流引诱的锁孔后壁凸起是激发锁孔不稳固的要害要素。施加横向磁场，经由过程二次热电磁流体能源学（TEMHD）驱动的活动来转变净涡流散布，从而克制锁孔的不稳固性。这最年夜限制地增加了凸起跟年夜振幅的锁孔振荡。克制后果取决于绝对于磁场偏向的激光扫描偏向，由于这把持了塞贝克效应引诱的洛伦兹力偏向。成果标明，在LPBF长度标准下，电磁阻尼效应较弱，对塞贝克系数较年夜的合金，TEMHD成为把持锁孔后活动的主导机制。▲ Abstract：Keyhole instability during laser welding and laser powder bed fusion (LPBF) can cause keyhole collapse and pore formation. Using high-speed x-ray imaging, we demonstrate that the flow vortex–induced protrusion on the rear keyhole wall is crucial in initiating keyhole instability. Applying a transverse magnetic field suppresses the keyhole instability by driving a secondary thermoelectric magnetohydrodynamics (TEMHD) flow that alters the net flow vortex. This minimizes protrusions and large-amplitude keyhole oscillations. The suppression effectiveness depends on the laser scanning direction relative to the magnetic field orientation because this controls the Seebeck effect–induced Lorentz force’s direction. We show that at LPBF length scales, electromagnetic damping is weak, and for alloys with a large Seebeck coefficient, TEMHD becomes the dominant mechanism controlling flow behind the keyhole.人工智能Artificial IntelligenceMaterial-like robotic collectives with spatiotemporal control of strength and shape存在强度跟外形时空把持的类资料呆板人聚集体▲ 作者：MATTHEW R. DEVLIN, SANGWOO KIM, OTGER CAMPS AND ELLIOT W. HAWKES▲ 链接：https://www.science.org/doi/10.1126/science.ads7942▲择要：呆板人资料的愿景（呆板人单位的自构造聚集体，可能陈列成存在可调控物感性质的任何情势）临时以来始终惹起迷信界跟科幻界的兴致。但是，这一愿景须要战胜一个基础的物理挑衅：聚集体必需强盛以支撑负荷，但也能产生形变以采用新的情势。研讨组经由过程调理单位间的剪切力来把持密沉积构造中单位的拓扑重排，从而在类资料呆板人聚集体中实现了这一点。这实现了在聚集体中部分把持固体状况跟流体状况之间的刚性转换，以及对外形跟强度的时空把持。研讨组展现了却构构成跟愈合，并展现了在本身分量下产生形变之前，聚集体可能承重700牛顿（呆板人分量的500倍）。▲ Abstract：The vision of robotic materials—cohesive collectives of robotic units that can arrange into virtually any form with any physical properties—has long intrigued both science and fiction. Yet, this vision requires a fundamental physical challenge to be overcome: The collective must be strong, to support loads, yet flow, to take new forms. We achieve this in a material-like robotic collective by modulating the interunit tangential forces to control topological rearrangements of units within a tightly packed structure. This allows local control of rigidity transitions between solid and fluid-like states in the collective and enables spatiotemporal control of shape and strength. We demonstrate structure-forming and healing and show the collective supporting 700 newtons (500 times the weight of a robot) before “melting” under its own weight.化学ChemistrySpiro-C(sp3)-atom transfer: Creating rigid three-dimensional structures with Ph2SCN2螺C（sp3）-原子转移：用Ph2SCN2创立刚性三维构造▲ 作者：QIU SUN, JAN-NIKLAS BELTING, JULIAN HAUDA, DAVID TYMANN, PATRICK W. ANTONI, RICHARD GODDARD, ET AL.▲ 链接：https://www.science.org/doi/10.1126/science.ads5974▲ 择要：将单个C原子引入无机底物平日会构成含有不饱跟C（sp）核心的立体分子。增加一个由四个σ-C-C键包抄的单个C（sp3）—原子，构建三维破体构造，是分解化学中尚未处理的挑衅。研讨组报道了重氮硫叶破德Ph2S=C=N2试剂的分解跟利用，该试剂联合了硫叶破德跟重氮化合物的反映性，经由过程次序或单步构建C（sp3）—原子以通用方法发生螺碳核心。以C（sp3）—原子为核心能够构成新的C-C跟C-X（此中X为O或N）键，终极可在无需借助过渡金属催化的情形下一步构成4个C-C σ-键。Ph2SCN2也可用于制备含有氧杂螺[2.2]戊烷以及三环螺旋化合物的高张力骨架。▲ Abstract：The introduction of a single C-atom into organic substrates typically results in the formation of flat molecules containing unsaturated C(sp)-centers. Adding a single C(sp3)-atom surrounded by four σ-C–C bonds, which opens up the three-dimensional space, is an unresolved problem in synthetic chemistry. We report the synthesis and application of the diazosulfur ylide Ph2S=C=N2 reagent that combines the reactivity of both sulfur ylides and diazo compounds to create carbon spiro-centers in a general fashion by the sequential or single-step installation of a C(sp3)-atom. New C–C and C–X (where X is O or N) bonds can be created around the C(sp3)-atom, which can ultimately be extended to four C–C σ-bonds in one step without resorting to transition metal catalysis. Ph2SCN2 can also be used to access highly strained frameworks containing (oxa)spiro[2.2]pentanes as well as tricyclic spiro-compounds.Visible light–triggered depolymerization of commercial polymethacrylates可见光激发商用聚甲基丙烯酸酯的解聚▲ 作者：HYUN SUK WANG, MIKHAIL AGRACHEV, HONGSIK KIM, NGHIA P. TRUONG, TAE-LIM CHOI, GUNNAR JESCHKE, ET AL.▲ 链接：https://www.science.org/doi/10.1126/science.adr1637▲择要：将存在碳—碳骨架的乙烯基聚合物转化为单体是缓解日益增加的塑料废料流的幻想道路。但是，解聚这种稳固的资料仍颇具挑衅，开始进的方式依附于既非贸易化出产也不合适现实利用的“计划”聚合物。在这项任务中，研讨组报道了一种主链激发、可见光触发的解聚，直接实用于含有未公然杂质（如共聚单体、增加剂或染料）的贸易聚合物。经由过程直接从溶剂华夏位天生氯自在基，能够实现聚甲基丙烯酸酯的近定量（ 98%）解聚，而不受分解道路（如自在基聚合或离子聚合）、端基跟分子量（高达160万道尔顿）的限度。停止多克级解聚跟付与时光把持的可能性使这种方式成为一种通用接纳道路。▲ Abstract：The reversion of vinyl polymers with carbon-carbon backbones to their monomers represents an ideal path to alleviate the growing plastic waste stream. However, depolymerizing such stable materials remains a challenge, with state-of-the-art methods relying on “designer” polymers that are neither commercially produced nor suitable for real-world applications. In this work, we report a main chain–initiated, visible light–triggered depolymerization directly applicable to commercial polymers containing undisclosed impurities (e.g., comonomers, additives, or dyes). By in situ generation of chlorine radicals directly from the solvent, near-quantitative ( 98%) depolymerization of polymethacrylates could be achieved regardless of their synthetic route (e.g., radical or ionic polymerization), end group, and molecular weight (up to 1.6 million daltons). The possibility to perform multigram-scale depolymerizations and confer temporal control renders this methodology a versatile and general route to recycling.地球迷信Earth ScienceHidden cascades of seismic ice stream deformation暗藏的地动性冰流变形级联▲ 作者：ANDREAS FICHTNER, COEN HOFSTEDE, BRIAN L. N. KENNETT, ANDERS SVENSSON, JULIEN WESTHOFF, FABIAN WALTER, ET AL.▲ 链接：https://www.science.org/doi/10.1126/science.adp8094▲择要：冰流是海立体变更的重要调理器。但是，因为对相干进程的不完整懂得，人们对冰流演化的尺度粘性活动模仿的猜测才能无限。在格陵兰冰盖上，基于钻孔光纤的观察提醒了一种与粘性活动实践不符的脆性变形形式，其长度标准与古代冰盖模子的辨别率类似：即在地表无奈观察到的冰震级联效应。冰震级联在火山起源杂质邻近成核，增进晶界开裂，表示为晶体标准原初塑性的微观情势。守旧估量标明，冰震级联或发生与年夜地丈量值振幅相称的应变率，从而在以后冰盖模子跟观察之间供给了一个可能缺掉的关系机制。▲ Abstract：Ice streams are major regulators of sea level change. However, standard viscous flow simulations of their evolution have limited predictive power owing to incomplete understanding of involved processes. On the Greenland ice sheet, borehole fiber-optic observations revealed a brittle deformation mode that is incompatible with viscous flow, over length scales similar to the resolution of modern ice sheet models: englacial ice quake cascades that are unobservable at the surface. Nucleating near volcanism-related impurities that promote grain boundary cracking, the ice quake cascades appear as a macroscopic form of crystal-scale wild plasticity. A conservative estimate indicates that seismic cascades are likely to produce strain rates that are comparable in amplitude with those measured geodetically, providing a plausible missing link between current ice sheet models and observations.