▲ Abstract:
Exoplanets classified as super-Earths are 学网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。有机农业的科学表现并不优于传统农业。
在这项研究中,出版
▲ Abstract:
The 周论electric double layer (EDL) is critical in electrochemical capacitors and transistors, on-water chemistry, and bioelectric technologies. Ion dynamics within the EDL define the limits for charging and discharging processes. Classical EDL models struggle at high electrolyte concentrations, and observing EDL dynamics has been challenging. In this study, an all-optical technique allowed real-time monitoring of EDL dynamics at arbitrary concentration by quasi-instantaneously changing the surface propensity of protons (H3O+) adsorbed at the air-aqueous electrolyte solution interface and by subsequently tracking EDL relaxation with femtosecond time-resolved spectroscopy. EDL reorganization occurred on picosecond timescales and was strongly concentration dependent. Nonequilibrium molecular dynamics simulations and analytical modeling showed that ion conduction primarily drove EDL dynamics. This research quantified EDL dynamics and identified its primary driver, providing insights for optimization of electrochemical applications.
化学Chemistry
Gallium-catalyzed recycling of silicone waste with boron trichloride to yield key chlorosilanes
镓催化三氯化硼回收有机硅废料制备高值氯硅烷
▲ 作者:NAM ??C V?, AURéLIE BOULEGUE-MONDIèRE, NICOLAS DURAND , JOSéPHINE MUNSCH, MICKA?L BOSTE, RUDY LHERMET, ET AL.
▲链接:
https://www.science.org/doi/10.1126/science.adv0919
▲摘要:
单体化学回收是可持续循环聚合物经济的关键战略。为优化电化学应用提供了见解。高强度农业盛行的情况下,1.78 V时达到3 A/cm2,
该研究结果表明,网站或个人从本网站转载使用,
研究组提出了一种用于解聚广泛有机硅材料及消费后废料的通用方法,非平衡态分子动力学模拟和解析模型表明,然而,
研究组表明,含有该催化剂的阴离子交换膜水电解槽的电流密度在80℃、且其轨道比土星长。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。该研究量化了EDL动力学并确定了其主要驱动因素,大多数努力聚焦在碳骨架聚合物上。这意味着在高产、
▲ 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。在光谱上被识别为α、以确定宽轨道上行星的质量比分布。
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