海水苦泪水甜 短评《墨香铜臭》倦倦子 ^第1章^ 最新更新:2022-02-05 01...
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海水苦泪水甜 短评《墨香铜臭》倦倦子 ^第1章^ 最新更新:2022-02-05 01...
以色列国防军表示通过袭击指挥中心、军事大院和反坦克导弹发射场杀死了其他哈马斯和巴勒斯坦伊斯兰圣战人员并削弱了他们的作战能力
《科学》(20220107出版)一周论文导读2022-01-09 19:59·科学网编译 | 未玖Science, 7 JANUARY 2022, VOL 375, ISSUE 6576《科学》2022年1月7日,第375卷,6576期物理学PhysicsEvidence for a delocalization quantum phase transition without symmetry breaking in CeCoIn5CeCoIn5非对称破缺离域量子相变的证据▲ 作者:NIKOLA MAKSIMOVIC, DANIEL H. EILBOTT, TESSA COOKMEYER, FANGHUI WAN, JAN RUSZ, VIKRAM NAGARAJAN, et al.▲ 链接:https://www.science.org/doi/10.1126/science.aaz4566▲ 摘要量子相变研究与对称破缺没有明显关联,这是凝聚态物理学的一个重大研究方向,特别是高温超导问题,这种相变被认为是超导机制本身的基础。研究组认为在典型的非常规超导体CeCoIn5中,假定的量子临界点由连接两个不同体积费米面跃迁中的电子离域所表征,没有明显的对称破缺。利用已建立的f-电子金属理论,研究组讨论了如何解释这种涉及自旋-电荷分离的跃迁,该模型可有效描述他们测量霍尔效应的异常输运行为。▲ AbstractThe study of quantum phase transitions that are not clearly associated with broken symmetry is a major effort in condensed matter physics, particularly in regard to the problem of high-temperature superconductivity, for which such transitions are thought to underlie the mechanism of superconductivity itself. Here we argue that the putative quantum critical point in the prototypical unconventional superconductor CeCoIn5 is characterized by the delocalization of electrons in a transition that connects two Fermi surfaces of different volumes, with no apparent broken symmetry. Drawing on established theory of f-electron metals, we discuss an interpretation for such a transition that involves the fractionalization of spin and charge, a model that effectively describes the anomalous transport behavior we measured for the Hall effect.材料科学Materials ScienceSingle-walled zeolitic nanotubes单壁分子筛纳米管▲ 作者:AKSHAY KORDE, BYUNGHYUN MIN, ELINA KAPACA, OMAR KNIO, IMAN NEZAM, ZIYUAN WANG, et al.▲ 链接:https://www.science.org/doi/10.1126/science.abg3793▲ 摘要研究组报道了具有微孔分子筛壁的单壁硅酸铝纳米管的合成和结构。这种准一维分子筛由波拉型结构导向剂(SDA)组装而成,该分子筛含有一个中心联苯基团,由C10烷基链连接到奎宁环端基。高分辨率电子显微镜和衍射及其他支持方法揭示了一种独特的壁结构,它是两种分子筛结构类型(β和MFI)的特征构建层的混合体。这种混合结构产生于弯曲纳米管壁形成过程中应变能的最小化。由于SDA分子的自组装,纳米管的形成导致介观结构的早期出现。SDA分子的联苯核心基团证明了π堆积,外围的奎宁环基团则证明了微孔壁结构。▲ AbstractWe report the synthesis and structure of single-walled aluminosilicate nanotubes with microporous zeolitic walls. This quasi-one-dimensional zeolite is assembled by a bolaform structure-directing agent (SDA) containing a central biphenyl group connected by C10 alkyl chains to quinuclidinium end groups. High-resolution electron microscopy and diffraction, along with other supporting methods, revealed a unique wall structure that is a hybrid of characteristic building layers from two zeolite structure types, beta and MFI. This hybrid structure arises from minimization of strain energy during the formation of a curved nanotube wall. Nanotube formation involves the early appearance of a mesostructure due to self-assembly of the SDA molecules. The biphenyl core groups of the SDA molecules show evidence of π stacking, whereas the peripheral quinuclidinium groups direct the microporous wall structure.Metastable Dion-Jacobson 2D structure enables efficient and stable perovskite solar cells亚稳态Dion-Jacobson二维结构实现高效稳定的钙钛矿太阳能电池▲ 作者:FEI ZHANG, SO YEON PARK, CANGLANG YAO, HAIPENG LU, SEAN P. DUNFIELD, CHUANXIAO XIAO, et al.▲ 链接:https://www.science.org/doi/10.1126/science.abj2637▲ 摘要三维(3D)有机-无机卤化物钙钛矿太阳能电池(PSC)的性能可通过使用具有高效电荷传输的2D层状钙钛矿进行表面处理来增强。研究组最大化了亚稳态Dion-Jacobson(DJ)2D钙钛矿层的空穴传输,调整了不对称大体积有机分子的定向排列。空穴传输的能垒降低后,面外传输速率提高了4~5倍,2D PSC的电源转换效率(PCE)为4.9%。通过亚稳态DJ 2D表面层,三种常见3D PSC的PCE提高了大约12%~16%,最终可高达约24.7%。对于三元阳离子混合卤化物PSC,在约40℃的氮气中,一倍太阳光强照射1000小时后,初始PCE仍可保持90%。▲ AbstractThe performance of three-dimensional (3D) organic-inorganic halide perovskite solar cells (PSCs) can be enhanced through surface treatment with 2D layered perovskites that have efficient charge transport. We maximized hole transport across the layers of a metastable Dion-Jacobson (DJ) 2D perovskite that tuned the orientational arrangements of asymmetric bulky organic molecules. The reduced energy barrier for hole transport increased out-of-plane transport rates by a factor of 4 to 5, and the power conversion efficiency (PCE) for the 2D PSC was 4.9%. With the metastable DJ 2D surface layer, the PCE of three common 3D PSCs was enhanced by approximately 12 to 16% and could reach approximately 24.7%. For a triple-cation–mixed-halide PSC, 90% of the initial PCE was retained after 1000 hours of 1-sun operation at ~40°C in nitrogen.Capturing the swelling of solid-electrolyte interphase in lithium metal batteries观测锂金属电池固体电解质中间相的膨胀▲ 作者:ZEWEN ZHANG, YUZHANG LI, RONG XU, WEIJIANG ZHOU, YANBIN LI, SOLOMON T. OYAKHIRE, et al.▲ 链接:https://www.science.org/doi/10.1126/science.abi8703▲ 摘要尽管液-固界面是广泛科学领域的基础,但由于现有工具在纳米尺度上同时进入液相和固相存在缺陷,因此表征这种微妙的界面仍然很困难。这导致人们对电池体系关键界面的结构和化学性质的理解存在很大差距。研究组采用并改良了一种薄膜玻璃化方法,在天然液体电解质环境中保护电池中敏感而关键的界面,以实现低温电子显微镜和光谱学观测。他们报道了各种电解液中锂金属负极上的固体电解质中间相(SEI)存在大量膨胀。膨胀行为取决于电解质的化学性质,且与电池性能高度相关。较高程度的SEI膨胀往往表现出较差的电化学循环。▲ AbstractAlthough liquid-solid interfaces are foundational in broad areas of science, characterizing this delicate interface remains inherently difficult because of shortcomings in existing tools to access liquid and solid phases simultaneously at the nanoscale. This leads to substantial gaps in our understanding of the structure and chemistry of key interfaces in battery systems. We adopt and modify a thin film vitrification method to preserve the sensitive yet critical interfaces in batteries at native liquid electrolyte environments to enable cryo–electron microscopy and spectroscopy. We report substantial swelling of the solid-electrolyte interphase (SEI) on lithium metal anode in various electrolytes. The swelling behavior is dependent on electrolyte chemistry and is highly correlated to battery performance. Higher degrees of SEI swelling tend to exhibit poor electrochemical cycling.地球科学Earth ScienceOn the relative temperatures of Earth’s volcanic hotspots and mid-ocean ridges地球火山热点和大洋中脊的相对温度▲ 作者:XIYUAN BAO, CAROLINA R. LITHGOW-BERTELLONI, MATTHEW G. JACKSON, AND BARBARA ROMANOWICZ▲ 链接:https://www.science.org/doi/10.1126/science.abj8944▲ 摘要火山热点被认为是由来自深部地幔的热的、活跃的上升羽流供给的,其过余温度(Tex)比大洋中脊高约100~300℃。然而,Tex的估计被限制在地理覆盖范围内,且对于单个热点往往不一致。研究组通过将地震速度转换为温度来同时推断海洋热点和洋脊的温度。他们表明,虽然约45%的羽流供给热点很热(Tex≥155℃),但约15%较冷(Tex≤36℃),且约40%的温度不足以从深部地幔主动上涌(50℃≤Tex≤136℃)。热点具有极高的氦-3/氦-4比率和浮力通量,但较冷的热点则不然。后者可能起源于上地幔深处,或供给它们的深羽流被小规模对流夹带和冷却。▲ AbstractVolcanic hotspots are thought to be fed by hot, active upwellings from the deep mantle, with excess temperatures (Tex) ~100° to 300°C higher than those of mid-ocean ridges. However, Tex estimates are limited in geographical coverage and often inconsistent for individual hotspots. We infer the temperature of oceanic hotspots and ridges simultaneously by converting seismic velocity to temperature. We show that while ~45% of plume-fed hotspots are hot (Tex ≥ 155°C), ~15% are cold (Tex ≤ 36°C) and ~40% are not hot enough to actively upwell (50°C ≤ Tex ≤ 136°C). Hot hotspots have an extremely high helium-3/helium-4 ratio and buoyancy flux, but cold hotspots do not. The latter may originate at upper mantle depths. Alternatively, the deep plumes that feed them may be entrained and cooled by small-scale convection.公共卫生Public HealthImmune correlates analysis of the mRNA-1273 COVID-19 vaccine efficacy clinical trialmRNA-1273新冠疫苗效力临床试验的免疫相关分析▲ 作者:PETER B. GILBERT, DAVID C. MONTEFIORI, ADRIAN B. MCDERMOTT, YOUYI FONG, DAVID BENKESER, WEIPING DENG, et al.▲ 链接:https://www.science.org/doi/10.1126/science.abm3425▲ 摘要冠状病毒效力(COVE)3期临床试验评估了疫苗接种者的中和抗体和结合抗体,并与COVID-19疾病风险和保护作用相关联。在第二次接种疫苗时和4周后测量这些免疫标记物,且数值以标准化的世界卫生组织国际单位报告。所有标志物都与COVID-19风险呈负相关,并与疫苗效力直接相关。接种后50%中和滴度为10、100和1000的疫苗接种者估计疫苗效力分别为78%、91%和96%。这些结果有助于确定与保护相关的免疫标记物,并有望指导信使RNA(mRNA)COVID-19疫苗和其他COVID-19疫苗的批准决策。▲ AbstractIn the coronavirus efficacy (COVE) phase 3 clinical trial, vaccine recipients were assessed for neutralizing and binding antibodies as correlates of risk for COVID-19 disease and as correlates of protection. These immune markers were measured at the time of second vaccination and 4 weeks later, with values reported in standardized World Health Organization international units. All markers were inversely associated with COVID-19 risk and directly associated with vaccine efficacy. Vaccine recipients with postvaccination 50% neutralization titers 10, 100, and 1000 had estimated vaccine efficacies of 78% (95% confidence interval, 54 to 89%), 91% (87 to 94%), and 96% (94 to 98%), respectively. These results help define immune marker correlates of protection and may guide approval decisions for messenger RNA (mRNA) COVID-19 vaccines and other COVID-19 vaccines.怎么说呢,咱来看看当年轰动汽车产业,以至于直接改变国补政策的骗补门就明白了。