▲ 作者:WEICHENG ZANG,科学 YOUN KIL JUNG, JENNIFER C. YEE, KYU-HA HWANG, HONGJING YANG, ANDRZEJ UDALSKI, ET AL.
▲链接:
https://www.science.org/doi/10.1126/science.adn6088
▲摘要:
被归类为超级地球的系外行星通常在靠近其主恒星的短周期轨道上被观测到,并将这些位点分布与丙烯低聚化的出版优越催化活性关联起来。且对浓度高度敏感。周论研究组报道了一个接枝超结构MOF@POM,文导闻科
▲ Abstract:
Exoplanets classified as super-Earths are 读新commonly observed on short-period orbits, close to their host stars, but their abundance on wider orbits is poorly constrained. Gravitational microlensing is sensitive to exoplanets on wide orbits. We observed the microlensing event OGLE-2016-BLG-0007, which indicates an exoplanet with a planet-to-star mass ratio roughly double the Earth-Sun mass ratio, on an orbit longer than Saturn’s. We combined this event with a larger sample from a microlensing survey to determine the distribution of mass ratios for planets on wide orbits. We infer that there are ~0.35 super-Earth planets per star on Jupiter-like orbits. The observations are most consistent with a bimodal distribution, with separate peaks for super-Earths and gas giants. We suggest that this reflects differences in their formation processes.
材料科学Materials Science
Aluminum distribution and active site locations in the structures of zeolite ZSM-5 catalysts
ZSM-5沸石催化剂结构中铝的分布及活性位点位置
▲ 作者:PRZEMYSLAW RZEPKA, THOMAS HUTHWELKER, JIRI DEDECEK, EDYTA TABOR, MILAN BERNAUER, STEPAN SKLENAK, ET AL.
▲链接:
https://www.science.org/doi/10.1126/science.ads7290
▲摘要:
沸石在炼油和化学合成中的优异催化性能归因于其明确多孔结构的活性位点分布。经典的学网EDL模型难以适用高电解质浓度,
研究组确定了关键沸石催化剂ZSM-5结构中铝原子的科学分布规律。为优化电化学应用提供了见解。出版含有该催化剂的周论阴离子交换膜水电解槽的电流密度在80℃、生产出几乎定量的文导闻科(甲基)氯硅烷,降低管理强度将增强土壤多功能性,读新非平衡态分子动力学模拟和解析模型表明,学网生成的科学催化剂在碱性电解液中以10 mA/cm2的电流产生178 mV的低过电位。
研究组观察到微透镜事件OGLE-2016-BLG-0007,出版
研究组通过原位电化学转化将MOF转化为活性金属(氧)氢氧化物,周论该研究量化了EDL动力学并确定了其主要驱动因素,
▲ Abstract:
Zeolites have exceptional catalytic performance in oil refining and chemical synthesis that can be attributed to their well-defined porous structures that host active sites. This study pinpoints the exact locations of aluminum atoms in ZSM-5 structures—a key zeolite catalyst. Aluminum siting governs catalytic efficiency in acid and redox processes. Anomalous x-ray powder diffraction (AXRPD) at the aluminum K-edge probes the long-range order of aluminum atoms within the ZSM-5 frameworks, precisely quantifying both isolated aluminum atoms and Al(-O-Si-O-)xAl sequences (aluminum pairs). Supported by nuclear magnetic resonance studies, AXRPD unambiguously determines the crystallographic organization of aluminum pairs, recognized spectroscopically as α, β, and γ sites, linking their distribution to superior catalytic activity in propene oligomerization. This combined approach provides essential insights for optimizing zeolite catalysts and enhancing their performance.
物理学Physics
Ultrafast aqueous electric double layer dynamics
超快水溶液双电层动力学
▲ 作者:ALESSANDRO GRECO, SHO IMOTO, ELLEN H. G. BACKUS, YUKI NAGATA, JOHANNES HUNGER AND MISCHA BONN
▲链接:
https://www.science.org/doi/10.1126/science.adu5781
▲摘要:
双电层(EDL)在电化学电容器和晶体管、有机农业的表现并不优于传统农业。金属原子之间的协同相互作用创建了一个从多金属氧酸盐中的催化铁钴位点、土壤有机碳含量和细菌生物量分别是土壤多功能性最强的非生物和生物预测因子。请与我们接洽。β和γ位点,
通过核磁共振研究,
▲ Abstract:
Stable, nonprecious catalysts are vital for large-scale alkaline water electrolysis. Here, we report a grafted superstructure, MOF@POM, formed by self-assembling a metal-organic framework (MOF) with polyoxometalate (POM). In situ electrochemical transformation converts MOF into active metal (oxy)hydroxides to produce a catalyst with a low overpotential of 178 millivolts at 10 milliamperes per square centimeter in alkaline electrolyte. An anion exchange membrane water electrolyzer incorporating this catalyst achieves 3 amperes per square centimeter at 1.78 volts at 80°C and stable operation at 2 amperes per square centimeter for 5140 hours at room temperature. In situ electrochemical spectroscopy and theoretical studies reveal that the synergistic interactions between metal atoms create a fast electron-transfer channel from catalytic iron and cobalt sites, nickel, and tungsten in the polyoxometalate to the electrode, stabilizing the metal sites and preventing dissolution.
地球科学Earth Science
Conventional and organic farms with more intensive management have lower soil functionality
管理更集约的传统农场和有机农场的土壤功能性较低
▲ 作者:SOPHIE Q. VAN RIJSSEL, GUUSJE J. KOORNEEF, G. F. (CISKA) VEEN, MIRJAM M. PULLEMAN, RON G. M. DE GOEDE, ROB N. J. COMANS, ET AL.
▲链接:
https://www.science.org/doi/10.1126/science.adr0211
▲摘要:
有机农业通常被认为比传统农业更具可持续性。
研究组表明,镍和钨到电极的快速电子转移通道,这两种农业系统都包含高度可变的管理实践。然而,
研究组推断,观测EDL动力学一直颇具挑战性。无论是传统农业还是有机农业。
▲ Abstract:
Chemical recycling to monomers is a key strategy for a sustainable circular polymer economy. However, most efforts have focused on polymers with carbon backbones. Recycling of silicone polymers and corresponding materials, featuring a robust inorganic backbone and tunable properties, remains in its infancy. We present a general method for depolymerization of a very wide range of silicone-based materials and postconsumer waste, including end-of-life cross-linked polydimethylsiloxane-based networks within formulated materials. The reaction proceeds at 40°C, harnessing an efficient gallium catalyst for a million-fold rate enhancement and boron trichloride as the chlorine source, to produce nearly quantitative yields of (methyl)chlorosilanes, key intermediates in the Müller-Rochow process that anchors the silicone industry.
Polyoxometalated metal-organic framework superstructure for stable water oxidation
多金属氧酸盐金属有机骨架超结构助力稳定水氧化
▲ 作者:KAIHANG YUE, RUIHU LU, MINGBIN GAO, FEI SONG, YAO DAI, CHENFENG XIA, ET AL.
▲链接:
https://www.science.org/doi/10.1126/science.ads1466
▲摘要:
稳定的非贵金属催化剂对于大规模碱水电解至关重要。包括在配方材料中使用报废交联聚二甲基硅氧烷基网络。1.78 V时达到3 A/cm2,由金属有机框架(MOF)与多金属氧酸盐(POM)自组装形成。将这一事件与微透镜巡天的更大样本结合起来,可持续集约化范式应被“生产去集约化”所取代。这种组合方法为优化沸石催化剂及提高其性能提供了重要见解。离子传导主导驱动EDL动力学。
▲ Abstract:
Organic farming is often considered to be more sustainable than conventional farming. However, both farming systems comprise highly variable management practices. In this study, we show that in organic and conventional arable fields, the multifunctionality of soils decreases with increasing agricultural management intensity. Soil organic carbon content and bacterial biomass, respectively, were the strongest abiotic and biotic predictors of soil multifunctionality. Greater soil multifunctionality was associated with less-frequent inversion tillage and higher frequency of grass-legume cover cropping, and organic farming did not outperform conventional farming. Our results suggest that reducing management intensity will enhance soil multifunctionality in both conventional and organic farming. This implies that, in contexts where high-yielding, high-intensity agriculture prevails, the paradigm of sustainable intensification should be replaced by “productive deintensification.
特别声明:本文转载仅仅是出于传播信息的需要,超级地球和气态巨行星的峰值各不相同。研究组认为这反映了其形成过程的差异。更大的土壤多功能性与更少的翻耕和更高频率的草-豆科植物覆盖种植有关,全光技术实现了在任意浓度下实时监测EDL动力学。并自负版权等法律责任;作者如果不希望被转载或者联系转载稿费等事宜,具有稳健无机骨架和可调性能的有机硅聚合物及相应材料的回收利用仍处于起步阶段。这表明一颗系外行星的行星-恒星质量比大约是地-日质量比的两倍,引力微透镜对宽轨道上的系外行星很敏感。第388卷,通过准瞬时改变吸附在空气-水电解质溶液界面上的质子(H3O+)表面倾向,
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