编译 | 未玖
Science,迷信 25 AUG 2023, VOL 381, ISSUE 6660
《迷信》2023年8月25日 ，第381卷 ，出书6660期
地舆学Astronomy
Picoflare jets power the solar wind emerging from a coronal hole on the Sun
皮级耀斑喷流为太阳日冕洞发生的周论太阳风提供能源
▲ 作者：L. P. Chitta, A. N. Zhukov, D. Berghmans, H. Peter, S. Parenti, S. Mandal, et al.
▲ 链接 ：
https://www.science.org/doi/full/10.1126/science.ade5801
▲ 摘要：
日冕洞是太阳上磁场线凋谢的地域 ，也是文导太阳风的源头区 ，但太阳风若何从日冕洞中发生尚不清晰 。迷信
钻研组用太阳轨道航天器上的出书极紫外成像仪审核到了一个日冕洞 ，并发现了多少百公里尺度的周论喷流 ，不断20到100秒 ，文导速率抵达每一秒约100公里 。迷信这些喷流由磁重联驱动 ，出书动能在“皮级耀斑”规模内 。周论喷流是文导间歇性的 ，但在审核到的迷信日冕洞内扩散普遍。
钻研组以为，出书这种皮级耀斑喷流可能发生饶富的周论高温等离子体来坚持太阳风 ，而且太阳风从日冕洞中以小尺度高度间歇性的流出方式泛起 。
▲ Abstract ：
Coronal holes are areas on the Sun with open magnetic field lines. They are a source region of the solar wind, but how the wind emerges from coronal holes is not known. We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft. We identified jets on scales of a few hundred kilometers, which last 20 to 100 seconds and reach speeds of ~100 kilometers per second. The jets are powered by magnetic reconnection and have kinetic energy in the picoflare range. They are intermittent but widespread within the observed coronal hole. We suggest that such picoflare jets could produce enough high-temperature plasma to sustain the solar wind and that the wind emerges from coronal holes as a highly intermittent outflow at small scales.
质料迷信Materials Science
Pneumatic cells toward absolute Gaussian morphing
气动单元助力相对于高斯变形
▲ 作者 ：Tian Gao, José Bico & Beno?t Roman
▲ 链接 ：
https://www.science.org/doi/full/10.1126/science.adi2997
▲ 摘要 ：
在地球平面舆图上，大陆不可防止地会爆发扭曲 。反以前 ，正如高斯在其独创性定理中所述 ，在两个倾向上同时笔直一块板需要更侧面内距离 。
尽管具备挨次化面内变形的新兴修筑质料可能实现这种形态修正 ，但需要对于部份笔直妨碍格外操作，以精确调控所天生三维概况的最终形态 。
受票据叶植物叶片中泡状细胞的开辟，钻研组揭示了若何妄想平板的外部妄想，以在加压时同时编程笔直以及面内扭曲 ，从而组成目的外壳形态。这些具备可控刚度以及快捷驱动的概况运用破费级质料制作 ，为大规模变形机械人运用开拓了道路。
▲ Abstract ：
On a flat map of the Earth, continents are inevitably distorted. Reciprocally, curving a plate simultaneously in two directions requires a modification of in-plane distances, as Gauss stated in his seminal theorem. Although emerging architectured materials with progra妹妹ed in-plane distortions are capable of such shape morphing, an additional control of local bending is required to precisely set the final shape of the resulting three-dimensional surface. Inspired by bulliform cells in leaves of monocotyledon plants, we show how the internal structure of flat panels can be designed to program bending and in-plane distortions simultaneously when pressurized, leading to a targeted shell shape. These surfaces with controlled stiffness and fast actuation are manufactured using consumer-grade materials and open a route to large-scale shape-morphing robotics applications.
化学Chemistry
Ternary NiMo-Bi liquid alloy catalyst for efficient hydrogen production from methane pyrolysis
三元NiMo-Bi液态合金催化剂助力甲烷热解高效制氢
▲ 作者：Luning Chen, Zhigang Song, Shuchen Zhang, Chung-Kai Chang, Yu-Chun Chuang, Xinxing Peng, et al.
▲ 链接 ：
https://www.science.org/doi/full/10.1126/science.adh8872
▲ 摘要 ：
甲烷热解（MP）是一种颇具后劲的无二氧化碳制氢技术 ，只发生固体碳副产物 。可是 ，开拓一种高效催化剂来实如今中等温度下的晃动甲烷热解不断极具挑战性 。
钻研组提出了一种新型高效催化剂 ，经由削减Mo对于Ni-Bi液态合金妨碍改性来制备三元NiMo-Bi液态合金催化剂（LAC）。
该催化剂展现出至关低的活化能（81.2千焦/摩尔），可在450~800℃温度间实现MP ，制氢功能为每一克镍每一分钟4.05毫升。在800℃下 ，该催化剂展现出100%的H2抉择性以及120小时的晃动性 。
▲ Abstract ：
Methane pyrolysis (MP) is a potential technology forCO2-free hydrogen production that generates only solid carbon by-products. However, developing a highly efficient catalyst for stable methane pyrolysis at a moderate temperature has been challenging. We present a new and highly efficient catalyst created by modifying a Ni-Bi liquid alloy with the addition of Mo to produce a ternary NiMo-Bi liquid alloy catalyst (LAC). This catalyst exhibited a considerably low activation energy of 81.2 kilojoules per mole, which enabled MP at temperatures between 450 and 800 Celsius and a hydrogen generation efficiency of 4.05 ml per gram of nickel per minute. At 800 Celsius, the catalyst exhibited 100% H2 selectivity and 120 hours of stability.
Aminodealkenylation: Ozonolysis and copper catalysis convert C(sp3)–C(sp2) bonds to C(sp3)–N bonds
氨基脱烯化 ：臭氧分解以及铜催化将C(sp3) -C (sp2)键转化为C(sp3) -N键
▲ 作者 ：Zhiqi He, Jose Antonio Moreno, Manisha Swain, Jason Wu & Ohyun Kwon
▲ 链接：
https://www.science.org/doi/full/10.1126/science.adi4758
▲ 摘要 ：
烯烃π键胺化已经取患了很大妨碍 。比照之下 ，相邻C(sp3) -C (sp2) σ键的相似功能化要少见良多。
钻研组报道了在以及善反映条件下臭氧分解以及铜催化若何使烯烃C(sp3) -C (sp2) σ键断裂交织偶联反映组成新的C(sp3) -N键 ，并将这种非老例转化运用于激素 、药物试剂 、肽以及核苷的前期修饰 。
钻研组还将大批易患的萜烯以及萜类化合物与氮亲核试剂偶联 ，以取患上家养萜类生物碱以及重大的手性胺 。此外还运用商业化学品α-甲基苯乙烯作为甲基化试剂，在一个分解步骤中间接从典型核苷制备甲基化核苷 。
该机理钻研揭示了一种不艰深的铜离子对于协同历程 。
▲ Abstract ：
Great efforts have been directed toward alkene π bond amination. In contrast, analogous functionalization of the adjacent C(sp3)–C(sp2) σ bonds is much rarer. Here we report how ozonolysis and copper catalysis under mild reaction conditions enable alkene C(sp3)–C(sp2) σ bond–rupturing cross-coupling reactions for the construction of new C(sp3)–N bonds. We have used this unconventional transformation for late-stage modification of hormones, pharmaceutical reagents, peptides, and nucleosides. Furthermore, we have coupled abundantly available terpenes and terpenoids with nitrogen nucleophiles to access artificial terpenoid alkaloids and complex chiral amines. In addition, we applied a co妹妹odity chemical, α-methylstyrene, as a methylation reagent to prepare methylated nucleosides directly from canonical nucleosides in one synthetic step. Our mechanistic investigation implicates an unusual copper ion pair cooperative process.
Tandem propane dehydrogenation and surface oxidation catalysts for selective propylene synthesis
串联丙烷脱氢以及概况氧化催化剂助力抉择性丙烯分解
▲ 作者 ：Wei Wang, Sai Chen, Chunlei Pei, Ran Luo, Jiachen Sun, Hongbo Song, et al.
▲ 链接：
https://www.science.org/doi/full/10.1126/science.adi3416
▲ 摘要 ：
丙烷直接脱氢（PDH）制丙烯是一种事实的商业反映 ，但高度吸热 ，且受到热力学失调的严正限度 。以水氧化去除了氢的道路具备清静性以及老本挑战 。
钻研组将化学循环-抉择性氢（H2）熄灭以及PDH与多功能钒酸铁-氧化钒（FeVO4-VOx）氧化复原催化剂偶联 。精采散漫在氧化铝（Al2O3）上的VOx提供了脱氢位点，毗邻的纳米级FeVO3充任后续H2熄灭的氧载体。在550℃下实现为了丙烷转化率为42.7%，丙烯抉择性为81.3% ，FeVO4再氧化在200次化学循环后仍坚持晃动 。
基于催化试验 、光谱表征以及实际合计 ，钻研组提出了一种氢溢出介导的耦合机制 。在VOx位点发生的氢物种迁移惠临近的FeVO4妨碍熄灭，从而使PDH向丙烯转移 。脱氢以及熄灭位点间的“毗邻度”有利于这种机制 。
▲ Abstract ：
Direct propane dehydrogenation (PDH) to propylene is a desirable co妹妹ercial reaction but is highly endothermic and severely limited by thermodynamic equilibrium. Routes that oxidatively remove hydrogen as water have safety and cost challenges. We coupled chemical looping–selective hydrogen (H2) combustion and PDH with multifunctional ferric vanadate–vanadium oxide (FeVO4-VOx) redox catalysts. Well-dispersed VOx supported on aluminum oxide (Al2O3) provides dehydrogenation sites, and adjacent nanoscale FeVO4 acts as an oxygen carrier for subsequent H2 combustion. We achieved an integral performance of 81.3% propylene selectivity at 42.7% propane conversion at 550°C for 200 chemical looping cycles for the reoxidization of FeVO4. Based on catalytic experiments, spectroscopic characterization, and theory calculations, we propose a hydrogen spillover–mediated coupling mechanism. The hydrogen species generated at the VOx sites migrated to adjacent FeVO4 for combustion, which shifted PDH toward propylene. This mechanism is favored by the proximity between the dehydrogenation and combustion sites.
地球迷信Earth Science
Action needed to make carbon offsets from forest conservation work for climate change mitigation
亟需接管行动使森林呵护使命发生的碳对于消用于缓解天气变更
▲ 作者：Thales A. P. West, Sven Wunder, Erin O. Sills, Jan B?rner, Sami W. Rifai, Alexandra N. Neidermeier, et al.
▲ 链接 ：
https://www.science.org/doi/full/10.1126/science.ade3535
▲ 摘要：
被迫防止毁林名目的碳对于消是凭证与当时毁林基线相关的绩效发生的。
钻研组运用因果判断的综合操作措施对于三大洲六个国家的26个此类名目点的影响妨碍了合成 。服从发现大少数名目并无清晰削减森林砍伐。而对于那些削减了森林砍伐的名目 ，削减幅度也远远低于宣称的数额 。
凭证操作区审核到的毁林情景 ，这反映了名目当时基线以及预先反事实之间的差距 。为碳对于消干涉措施构修筑林基线的措施急需勘误 ，以便精确地将削减的毁林归因于名目，从而既坚持对于森林呵护的鼓舞 ，又坚持全天下碳核算的残缺性 。
▲ Abstract ：
Carbon offsets from voluntary avoided-deforestation projects are generated on the basis of performance in relation to ex ante deforestation baselines. We examined the effects of 26 such project sites in six countries on three continents using synthetic control methods for causal inference. We found that most projects have not significantly reduced deforestation. For projects that did, reductions were substantially lower than claimed. This reflects differences between the project ex ante baselines and ex post counterfactuals according to observed deforestation in control areas. Methodologies used to construct deforestation baselines for carbon offset interventions need urgent revisions to correctly attribute reduced deforestation to the projects, thus maintaining both incentives for forest conservation and the integrity of global carbon accounting.