編譯｜馮維維
Science , 12 Jan 2024, Volume 383, Issue 6679
【科學】， 2024年1月12日，第383卷，6679期
物理學 Physics
Free-electron interaction with nonlinear optical states in microresonators
微諧振器中非線性光學態的自由電子相互作用
▲ 作者：YUJIA YANG, JAN-WILKE HENKE, ARSLAN S. RAJA, F. JASMIN KAPPERT, GUANHAO HUANG, GERMAINE AREND, ZHERU QIU, ARMIN FEIST, RUI NING WANG , AND TOBIAS J. KIPPENBERG
▲ 連結：
https://www.science.org/doi/10.1126/science.adk2489
▲ 摘要：
電子顯微鏡提供最小尺度的成像能力。從樣品中散射出來的電子束通常是能量穩定和空間均勻的。能夠調制光束以獲取樣本的時空資訊將是非常有用的，但在技術上具有挑戰性。
作者證明了微諧振器中誘導的非線性光學態可以與電子束相互作用，並將非線性光學態印在電子束上。這種相互作用為電子束的超快調制提供了途徑，並拓寬了電子顯微鏡在時空成像和光譜學方面的套用。
▲ Abstract：
Electron microscopes provide imaging capability on the tiniest of scales. The electron beams that scatter off the samples are generally energetically stable and spatially uniform. Being able to modulate the beam to access spatiotemporal information about the sample would be extremely useful but is technically challenging. Yang et al. demonstrate that the nonlinear optical states induced in a microresonator can interact with the electron beam and imprint the nonlinear optical states onto the beam. This interaction provides access to ultrafast modulation of the electron beam and broadens the application of electron microscopes for spatiotemporal imaging and spectroscopy.
Designing metainterfaces with specified friction laws
設計具有指定摩擦律的元介面
▲ 作者：ANTOINE AYMARD, EMILIE DELPLANQUE, DAVY DALMAS, AND JULIEN SCHEIBERT
▲ 連結：
https://www.science.org/doi/10.1126/science.adk4234
▲ 摘要：
輕觸式熒幕和機械手等許多器材都涉及摩擦接觸。最佳化這些裝置需要對界面的摩擦規律進行精細控制。目前缺乏系統的方法來建立其摩擦行為滿足預設規格的幹接觸界面。作者提出了一種通用的表面設計策略來制備具有法向力和摩擦力之間預定義關系的幹粗糙界面。
這種元界面透過將簡化的表面形貌視為球形凹凸體的集合，規避了摩擦學中通常的多尺度挑戰。最佳化單個凸起的高度可以使特定的摩擦規律有針對性。
透過各種厘米尺度的彈性體—玻璃元界面，研究者描述了三種可實作的摩擦定律，包括具有特定摩擦系數的線性定律和不尋常的非線性定律。這種設計策略代表了一種不依賴於規模和材料、無化學物質的節能和適應力智能介面途徑。
▲ Abstract：
Many devices, including touchscreens and robotic hands, involve frictional contacts. Optimizing these devices requires fine control of the interface’s friction law. We lack systematic methods to create dry contact interfaces whose frictional behavior satisfies preset specifications. We propose a generic surface design strategy to prepare dry rough interfaces that have predefined relationships between normal and friction forces. Such metainterfaces circumvent the usual multiscale challenge of tribology by considering simplified surface topographies as assemblies of spherical asperities. Optimizing the individual asperities’ heights enables specific friction laws to be targeted. Through various centimeter-scaled elastomer-glass metainterfaces, we illustrate three types of achievable friction laws, including linear laws with a specified friction coefficient and unusual nonlinear laws. This design strategy represents a scale- and material-independent, chemical-free pathway toward energy-saving and adaptable smart interfaces.
化學 Chemistry
Synthetic dioxygenase reactivity by pairing electrochemical oxygen reduction and water oxidation
電化學氧還原與水氧化配對合成雙加氧酶的反應性
▲ 作者：MD. ASMAUL HOQUE, JAMES B. GERKEN, AND SHANNON S. STAHL
▲ 連結：
https://www.science.org/doi/10.1126/science.adk5097
▲ 摘要：
分子氧的反應性對清潔能源技術和綠色化學合成至關重要，但動力學障礙使這兩種套用復混成。在合成中，雙氧應能以完美的原子經濟性將氧原子轉移到兩個有機分子上，但這種反應性很少見。
單加氧酶通常透過犧牲一個氧原子來產生更活潑的氧化劑來還原啟用雙氧。研究者使用錳—四苯基紫質催化劑將電化學氧還原和水氧化配對，在兩個電極上生成活性錳—氧。
這個過程支持雙氧原子轉移到兩個硫醚受質分子上，產生兩個等量的亞碸和一個等量的雙氧。這種雙加氧酶的凈反應性不消耗電子，而是利用電化學能量來克服動力學障礙。
▲ Abstract：
The reactivity of molecular oxygen is crucial to clean energy technologies and green chemical synthesis, but kinetic barriers complicate both applications. In synthesis, dioxygen should be able to undergo oxygen atom transfer to two organic molecules with perfect atom economy, but such reactivity is rare. Monooxygenase enzymes commonly reductively activate dioxygen by sacrificing one of the oxygen atoms to generate a more reactive oxidant. Here, we used a manganese-tetraphenylporphyrin catalyst to pair electrochemical oxygen reduction and water oxidation, generating a reactive manganese-oxo at both electrodes. This process supports dioxygen atom transfer to two thioether substrate molecules, generating two equivalents of sulfoxide with a single equivalent of dioxygen. This net dioxygenase reactivity consumes no electrons but uses electrochemical energy to overcome kinetic barriers.
Twisted epitaxy of gold nanodisks grown between twisted substrate layers of molybdenum disulfide
在扭曲二硫化鉬襯底層間生長的金納米片的扭曲外延
▲ 作者：YI CUI, JINGYANG WANG, YANBIN LI, YECUN WU, EMILY BEEN, ZEWEN ZHANG, JIAWEI ZHOU, WENBO ZHANG, HAROLD Y. HWANG, AND YI CUI
▲ 連結：
https://www.science.org/doi/10.1126/science.adk5947
▲ 摘要：
晶體薄膜的外延生長通常從一個襯底開始。研究者報道了兩個二硫化鉬(MoS2)層都可以對金施加取向效應，他們在一個二硫化鉬襯底上生長金納米顆粒層，然後用第二層二硫化鉬薄膜覆蓋納米顆粒。
加熱後，納米顆粒被壓扁成納米片。對於兩個襯底之間較小的扭轉角（約7度），納米厚的金納米片采用介於兩個襯底之間的取向。這種排列的部份原因是金與硫的化學相互作用。
▲ Abstract：
Epitaxial growth of a crystalline film normally proceeds from one substrate. Cui et al. report that two molybdenum disulfide (MoS2) layers can both impose orientation effects on gold. The authors grew gold nanoparticle layers on one MoS2 substrate and then covered the nanoparticles with a second MoS2 film. Upon heating, the nanoparticles flattened to nanodisks. For small twist angles between the two substrates (about 7 degrees), the nanometer-thick gold nanodisks adopted an orientation intermediate to both substrates. This alignment was driven in part by the chemical interaction of gold with sulfur.
保護生物學 Conservation biology
Comprehensive conservation assessments reveal high extinction risks across Atlantic Forest trees
大西洋森林林木滅絕風險很高
▲ 作者：RENATO A. F. DE, GILLES DAUBY, ANDRÉ L. DE GASPER, EDUARDO P. FERNANDEZ, ALEXANDER C. VIBRANS, ALEXANDRE A. DE OLIVEIRA, PAULO I. PRADO, VINÍCIUS C. SOUZA, MARINEZ F. DE SIQUEIRA, AND HANS TER STEEGE
▲ 連結：
https://www.science.org/doi/10.1126/science.abq5099
▲ 摘要：
全球生物多樣性正在下降，但許多生物多樣性熱點地區仍缺乏全面的物種保護評估。
研究者利用國際自然保育聯盟紅色名錄的多種滅絕風險評估標準和數以百萬計的植物標本館和森林清查記錄，對大西洋森林生物多樣性熱點地區的所有樹種（包括約1100種迄今未評估的樹種）進行了自動保護評估，約65%的物種和82%的特有物種被列為受威脅物種。
研究者重新發現了世界自然保育聯盟紅色名錄上被列為滅絕的5種物種，並確定了13種可能滅絕的地方性物種。物種資訊的不確定性對評估影響不大，但使用較少的紅色名錄標準嚴重低估了威脅水平。研究者認為，全世界熱帶森林的保護狀況比以前報道的要差。
▲ Abstract：
Biodiversity is declining globally, yet many biodiversity hotspots still lack comprehensive species conservation assessments. Using multiple International Union for Conservation of Nature (IUCN) Red List criteria to evaluate extinction risks and millions of herbarium and forest inventory records, we present automated conservation assessments for all tree species of the Atlantic Forest biodiversity hotspot, including ~1100 heretofore unassessed species. About 65% of all species and 82% of endemic species are classified as threatened. We rediscovered five species classified as Extinct on the IUCN Red List and identified 13 endemics as possibly extinct. Uncertainties in species information had little influence on the assessments, but using fewer Red List criteria severely underestimated threat levels. We suggest that the conservation status of tropical forests worldwide is worse than previously reported.
Global shark fishing mortality still rising despite widespread regulatory change
全球鯊魚捕撈死亡率仍在上升
▲ 作者：BORIS WORM , SARA OROFINO, ECHELLE S. BURNS, NIDHI G. D’COSTA, LEONARDO MANIR FEITOSA, MARIA L. D. PALOMARES, LAURENNE SCHILLER, AND DARCY BRADLEY
▲ 連結：
https://www.science.org/doi/10.1126/science.adf8984
▲ 摘要：
過去二十年，鯊魚越來越被認為是世界上最受威脅的野生動物之一，受到了更嚴格的科學和監管審查。然而，保護條例對鯊魚捕撈死亡率的影響尚未在全球範圍內進行評估。
研究者估計，2012年至2019年期間，捕撈總死亡率從至少7600萬條增加到8000萬條，其中約2500萬條是瀕危物種。沿海水域的死亡率增加了4%，但遠洋漁業的死亡率下降了7%，特別是在大西洋和西太平洋。
透過將捕撈死亡率數據與全球監管格局聯系起來，研究表明，旨在防止鯊魚鰭的廣泛立法並沒有降低死亡率，但區域鯊魚捕撈或保留禁令取得了一些成功。這些分析與專家訪談相結合，強調了以證據為基礎的解決方案，以扭轉對鯊魚的持續過度捕撈。
▲ Abstract：
Over the past two decades, sharks have been increasingly recognized among the world’s most threatened wildlife and hence have received heightened scientific and regulatory scrutiny. Yet, the effect of protective regulations on shark fishing mortality has not been evaluated at a global scale. Here we estimate that total fishing mortality increased from at least 76 to 80 million sharks between 2012 and 2019, ~25 million of which were threatened species. Mortality increased by 4% in coastal waters but decreased by 7% in pelagic fisheries, especially across the Atlantic and Western Pacific. By linking fishing mortality data to the global regulatory landscape, we show that widespread legislation designed to prevent shark finning did not reduce mortality but that regional shark fishing or retention bans had some success. These analyses, combined with expert interviews, highlight evidence-based solutions to reverse the continued overexploitation of sharks.
