編譯 |維酒
science, 8 dec 2023, vol 382, issue 6675
科學，2023 年 12 月 8 日，第 382 卷，第 6675 期
天文學
element abundance patterns in stars indicate fission of nuclei he**ier than uranium
恆星中元素豐度的模式表明，比鈾重的原子會發生核裂變
作者： Ian U roederer, nicole vassh, erika m. holmbeck, matthew r. mumpower, rebecca surman, john j. cowan, et al.
鏈結：
總結：
最重的化學元素是由中子星合併或超新星爆炸過程中的快中子俘獲過程（R過程）自然產生的。 對比較鈾重元素（超鈾原子核）的r過程生產知之甚少，並且實驗尚無法進行，因此必須使用核合成模型進行推導。
該研究小組分析了r-過程中元素增強的恆星樣本中的元素豐度。 釕、銠、鈀和銀元素的豐度（原子序數 z = 44 至 47;質量 a = 99 至 110） 與較重元素的豐度相關 （63 z 78， a > 150）。相鄰元素（34 z 42 和 48 z 62）之間沒有相關性。
研究小組將此解釋為超鈾核裂變碎片有助於豐度的證據。 結果表明，在r過程事件中產生了質量為>>260的富中子原子核。
▲ abstract：
the he**iest chemical elements are naturally produced by the rapid neutron-capture process (r-process) during neutron star mergers or supernovae. the r-process production of elements he**ier than uranium (transuranic nuclei) is poorly understood and inaccessible to experiments so must be extrapolated by using nucleosynthesis models. we examined element abundances in a sample of stars that are enhanced in r-process elements. the abundances of elements ruthenium, rhodium, palladium, and silver (atomic numbers z = 44 to 47; mass numbers a = 99 to 110) correlate with those of he**ier elements (63 ≤ z ≤ 78, a > 150). there is no correlation for neighboring elements (34 ≤ z ≤ 42 and 48 ≤ z ≤ 62). we interpret this as evidence that fission fragments of transuranic nuclei contribute to the abundances. our results indicate that neutron-rich nuclei with mass numbers >260 are produced in r-process events.
物理
on-demand entanglement of molecules in a reconfigurable optical tweezer array
可重構光鑷陣列中分子的按需糾纏
作者： Connor M holland, yukai lu & lawrence w. cheuk
鏈結：
總結：
量子糾纏對於許多量子應用至關重要，包括量子資訊處理、量子模擬和量子增強感測。 由於其豐富的內部結構和相互作用，分子被認為是量子科學的乙個有前途的平台。 然而，分子的確定性糾纏一直是乙個長期存在的實驗挑戰。
該研究小組利用可重構光鑷陣列製備的分子對之間的電偶極子相互作用，確定了性地建立貝爾分子對，從而證明了單獨製備的分子的按需糾纏。 這項研究的結果展示了量子應用所需的關鍵構建模組，並有望使用捕獲的分子推進量子增強的基礎物理測試。
▲ abstract：
entanglement is crucial to many quantum applications, including quantum information processing, quantum simulation, and quantum-enhanced sensing. because of their rich internal structure and interactions, molecules h**e been proposed as a promising platform for quantum science. deterministic entanglement of individually controlled molecules has nevertheless been a long-standing experimental challenge. we demonstrate on-demand entanglement of individually prepared molecules. using the electric dipolar interaction between pairs of molecules prepared by using a reconfigurable optical tweezer array, we deterministically created bell pairs of molecules. our results demonstrate the key building blocks needed for quantum applications and may advance quantum-enhanced fundamental physics tests that use trapped molecules.
材料科學
self-enhancing sono-inks enable deep-penetration acoustic volumetric printing
自增強聲吶油墨可實現深滲透聲學立體列印
作者： Xiao Kuang， Qiangzhou Rong， Saud Belal， Tri Vu， Alice M lópez lópez, nanchao wang, et al.
鏈結：
總結：
立體列印是一種新興的增材製造技術，它通過放棄逐漸更新油墨的步驟，提高了生成物體的列印速度和表面質量。 現有的立體印刷技術幾乎完全依靠光能來觸發透明油墨中的光聚合，這限制了材料選擇和構建尺寸。
該研究小組報告了一種用於深度滲透聲立體列印（D**P）的自增強超聲波墨水（或聲納墨水）的設計以及相應的聚焦超聲書寫技術。 實驗和聲學建模方法用於研究聲學列印行為與頻率和掃瞄速率的關係。
D**P 具有低聲流、快速聲熱聚合和大列印深度的關鍵特性，可列印各種形狀的體積水凝膠和奈米複合材料，無論其光學特性如何。 D**P 還可以在生物組織中進行厘公尺級深度的列印，為微創醫學鋪平道路。
▲ abstract：
volumetric printing, an emerging additive manufacturing technique, builds objects with enhanced printing speed and surface quality by forgoing the stepwise ink-renewal step. existing volumetric printing techniques almost exclusively rely on light energy to trigger photopolymerization in transparent inks, limiting material choices and build sizes. we report a self-enhancing sonicated ink (or sono-ink) design and corresponding focused-ultrasound writing technique for deep-penetration acoustic volumetric printing (d**p). we used experiments and acoustic modeling to study the frequency and scanning rate–dependent acoustic printing beh**iors. d**p achieves the key features of low acoustic streaming, rapid sonothermal polymerization, and large printing depth, enabling the printing of volumetric hydrogels and nanocomposites with various shapes regardless of their optical properties. d**p also allows printing at centimeter depths through biological tissues, p**ing the way toward minimally invasive medicine.
化學
kinetic and thermodynamic control of c(sp2)–h activation enables site-selective borylation
C（Sp2）-H活化的動力學和熱力學控制可實現位點選擇性硼化反應
作者： Jose B roque, alex m. shimozono, tyler p. pabst, gabriele hierlmeier, paul o. peterson & paul j. chirik
鏈結：
總結：
在不依賴空間效應或取向基團的情況下區分電子上不同的碳氫鍵 （c-h） 的催化劑很難設計。
在這項工作中，研究小組描述了一種由N-烷基咪唑取代的吡啶二羰烯（ACNC）螯合配體支援的鈷預催化劑，該配體能夠對氟芳烴進行非定向遠端硼化，並將範圍擴大到包括富電子芳烴、吡啶、三氟芳烴和二氟甲基化芳烴，從而解決了第一排過渡金屬C-H官能化催化劑的主要侷限性之一。
雖然鄰位C-H活化產生的鈷芳基絡合物在熱力學上更優越，但機理研究表明，間位C-H活化在動力學上更優越。 因此，本研究初步證明了c-H硼化反應中可切換位點的選擇性可以作為硼試劑使用單一預催化劑。
▲ abstract：
catalysts that distinguish between electronically distinct carbon-hydrogen (c–h) bonds without relying on steric effects or directing groups are challenging to design. in this work, cobalt precatalysts supported by n-alkyl-imidazole–substituted pyridine dicarbene (acnc) pincer ligands are described that enable undirected, remote borylation of fluoroaromatics and expansion of scope to include electron-rich arenes, pyridines, and tri- and difluoromethoxylated arenes, thereby addressing one of the major limitations of first-row transition metal c–h functionalization catalysts. mechanistic studies established a kinetic preference for c–h bond activation at the meta-position despite cobalt-aryl complexes resulting from ortho c–h activation being thermodynamically preferred. switchable site selectivity in c–h borylation as a function of the boron reagent was thereby preliminarily demonstrated using a single precatalyst.
地球科學
drought sensitivity in mesic forests heightens their vulnerability to climate change
濕地森林對乾旱的敏感性加劇了其對氣候變化的脆弱性
作者：Robert Heilmayr、Joan Dudney 和 Frances C moore
鏈結：
總結：
氣候變化正在改變世界各地森林的結構和功能，因此迫切需要**哪些森林最容易受到未來更熱、更乾燥的氣候的影響。
研究團隊分析了來自122個物種的660萬個樹木年輪，以評估樹木對水和能源可用性的敏感性。 研究發現，生長在氣候範圍內潮濕地區的樹木對乾旱的敏感性最大。 為了測試這些對乾旱敏感的模式如何影響對氣候變化的脆弱性，還研究了樹木生長到2024年。
結果表明，乾旱地區的乾旱適應將部分緩衝樹木免受氣候變化的影響。 相比之下，在氣候範圍內較潮濕和較熱的地區生長的樹木在氣候變化下可能會遭受意想不到的巨大不利影響。
▲ abstract：
climate change is shifting the structure and function of global forests, underscoring the critical need to predict which forests are most vulnerable to a hotter and drier future. we analyzed 6.6 million tree rings from 122 species to assess trees’ sensitivity to water and energy **ailability. we found that trees growing in wetter portions of their range exhibit the greatest drought sensitivity. to test how these patterns of drought sensitivity influence vulnerability to climate change, we predicted tree growth through 2100. our results suggest that drought adaptations in arid regions will partially buffer trees against climate change. by contrast, trees growing in the wetter, hotter portions of their climatic range may experience unexpectedly large adverse impacts under climate change.
watershed sediment cannot offset sea level rise in most us tidal wetlands
美國大多數潮汐濕地的流域沉積物並不能抵消海平面上公升的影響
以 Scott H ensign, joanne n. halls & erin k. peck
鏈結：
總結：
流域沉積物可以增加潮汐濕地的海拔高度以應對海平面上公升，但流域沉積物在何處以及在多大程度上起著尚不清楚的作用。
通過結合美國4,972條河流及其河口的沉積物負荷和潮汐濕地面積的連續資料集，該團隊計算出，在72%的河流中，河流沉積物的增加不足以與海平面上公升競爭，因為大多數流域太小（中位數為21平方公里）無法產生足夠的沉積物。
近一半的潮汐濕地將需要10倍以上的河流沉積物來抵消海平面上公升，在某些地區，即使拆除水壩也無法做到這一點。認識到流域沉積物對大多數潮汐濕地的高程幾乎沒有影響，研究重點應轉移到對高程變化影響最大的生物過程和沿海沉積物動力學上。
▲ abstract：
watershed sediment can increase elevation of tidal wetlands struggling against rising seas, but where and how much watershed sediment helps is unknown. by combining contiguous us datasets on sediment loads and tidal wetland areas for 4972 rivers and their estuaries, we calculated that river sediment accretion will be insufficient to match sea level rise in 72% of cases because most watersheds are too small (median 21 square kilometers) to generate adequate sediment. nearly half the tidal wetlands would require 10 times more river sediment to match sea level, a magnitude not generally achievable by dam removal in some regions. the realization that watershed sediment has little effect on most tidal wetland elevations shifts research priorities toward biological processes and coastal sediment dynamics that most influence elevation change.