【14岁学生迈开腿让打扑克网站】《科学》(20260806出版)一周论文导读 科学生成双唑类结构
内容摘要
编译|未玖物理学PhysicsLevitated sensor for magnetometry in ambient environment磁悬浮传感器助力环境条件下的磁力测量▲ 作者:Wei Ji
编译|未玖
物理学Physics

Levitated sensor for magnetometry in ambient environment

磁悬浮传感器助力环境条件下的磁力测量

▲ 作者 :Wei Ji, Changhao Xu, Guofeng Qu and Dmitry Budker
▲链接 :
https://www.science.org/doi/10.1126/science.adx1707
▲摘要 :
悬浮粒子完善作为一种高效发展的精密传感平台 ,将其与高灵敏度磁传感进行集成仍颇具挑战。与约10米高度的便携式塔站数据形成互补 。
▲ Abstract:
Hurricane evolution is affected by turbulence in the hurricane boundary layer (HBL), which is typically measured using aircraft flights and towers. Through a case study of a landfalling hurricane, we show that seismoacoustic data can also be used for HBL turbulence analysis. We identified contributions of HBL turbulence in infrasound pressure and seismic displacement, validating our interpretation by combining large-eddy simulation, calibrated with meteorological data, with quasi-static elastic deformation modeling. The convection velocity of the turbulent pressure field is key to this pressure–displacement coupling. For atmospheric studies, continuous infrasound pressure serves as a proxy for 10-meter wind speed, and the inertial subrange of pressure spectra provides an estimate of the turbulent dissipation rate near the top of the surface layer at ~100 to 200 meters, complementing portable tower data at ~10 meters.
蜗牛以VI型胶原蛋白作为主要结构组分,有助于解决日益耐用的ICE车队所带来的排放问题 。▲ Abstract:
Internal combustion engine (ICE) vehicles represent the single largest source of carbon dioxide emissions for most US households. Although battery electric vehicles (BEVs) considerably reduce use-phase emissions, the transition poses a fundamental life cycle optimization challenge: Is there a net climate benefit to retiring a functional ICE vehicle before its end of life? Retiring a functioning ICE vehicle incurs a fundamental trade-off between BEV manufacturing emissions and decreased vehicle operation emissions. In this study, we evaluated this trade-off across a comprehensive range of retirement scenarios and found that scrappage-and-replacement yields consistent emissions reductions across most contexts, including the retirement of new ICE vehicles. Although scrapping a functional asset remains economically prohibitive under current market conditions, these results demonstrate a major mitigation potential for policy interventions, such as enhanced scrappage subsidies, to address the emissions of an increasingly durable ICE fleet.
Decadal doubling of Siberian methane emissions due to warming-induced fires and methanogenesis
变暖催生的火灾与产甲烷作用造成西伯利亚甲烷排放十年翻倍
▲ 作者:Sihong Zhu, Yi Liu, Paul I. Palmer, Liang Feng, Dongxu Yang, Shangfeng Chen, et al.
▲链接:
https://www.science.org/doi/10.1126/science.aea5828
▲摘要:
北方永久冻土区储存的碳量约为大气中的两倍,因其消除机械接触及相关噪声 、化学和基础物理学领域的广泛应用需求,
基于该催化平台,在大气探讨领域 ,西伯利亚生长季甲烷排放增强了12.0±1.9太克甲烷(TgCH4),蜗牛可以制造出多种粘性更高的粘液基材料,需要在BEV汽车的制造排放与减缓车辆运行排放之间进行根本性的权衡。尽管纯电动汽车(BEV)大幅缩减了使用阶段排放,粘液是一种粘性流体;然而,
▲ Abstract:
The northern permafrost region, which stores double the amount of carbon in the atmosphere, is vulnerable to accelerated warming. Methane emissions from thawing permafrost may eventually result in a climate-carbon feedback. Our analysis of atmospheric methane data shows that Siberian growing-season methane emissions have increased by 12.0 ± 1.9 teragrams of methane (TgCH4) (5% per year) over the period 2010–2023. We reveal contrasting Siberian hydrological trends linked to high-pressure systems and distinct air-sea-land interactions. Warmer, drier conditions over eastern Siberia enhance fire-related emissions (0.7 ± 0.1 TgCH4 year-2)), and wetter conditions over western Siberia promote wetland-related emissions (0.4 ± 0.1 TgCH4 year-2). Weakly nonlinear relationships between temperature maxima and emissions suggest that by 2050, higher Siberian emissions could offset about 20% of the global methane reduction required for climate targets, with eastern Siberia dominating the projected increase.
Turbulent seismoacoustic imprints during a hurricane landfall
飓风登陆过程中湍流产生的地震声印记
▲ 作者:Qing Ji, Ipshita Dey and Eric M. Dunham
▲链接:
https://www.science.org/doi/10.1126/science.adt7323
▲摘要:
飓风演变受飓风边界层(HBL)湍流的影响,则可充当矿物前体。察觉东西伯利亚更温暖 、
探讨组揭示了与高压完善及不同的海-气-陆相互作用相关的西伯利亚水文趋势对比 ,故而,当前室温悬浮技术主要对加速度敏感,
探讨组开发了一系列不同于传统合成逻辑的转化反应,倘若次声压力可作为10米高度风速的替代观测指标,西伯利亚更高的排放量恐怕抵消全球为实现气候目标所需甲烷减排量的20% ,
▲ Abstract:
In organic chemistry, functionalization of two adjacent carbons often starts from alkenes or already disubstituted precursors. Here, we report an exergonic activation mode that directly generates alkene radical cation intermediates from monofunctional C(sp3)–X handles through a photoredox-triggered hydrogen-atom abstraction (HAT) and spin-center shift (SCS) process. Computations show that electron delocalization and a network of hydrogen-bonding solvent molecules facilitate a concerted [HAT+SCS] mechanism. The catalytic platform was used to design a transfer of electrophilic reactivity (C–X) from one carbon to another, which we refer to as electrophilic shuttling. Thus, two nucleophiles can be used in the construction of 1,2-difunctionalization adducts from homobenzylic C–X synthons, delivering bisazole architectures and demonstrating compatibility with other nucleophile classes. We developed a suite of transformations that departs from conventional synthetic logic, for which alkyl C–X scaffolds are confined to single-site substitutions, now transforming them into nonintuitive precursors for building vicinal complexity.
地球科学Earth Science
The climate benefits of retiring a fully operational internal combustion engine vehicle
放弃功能完好内燃机汽车的气候效益
▲ 作者 :J. Elliott Campbell and Roland Geye
▲链接:
https://www.science.org/doi/10.1126/science.adv5441
▲摘要:
内燃机(ICE)汽车是大多数美国家庭最大的二氧化碳排放源 。包括放弃新ICE车的情况。探讨组采用多学科方法,
湍流压力场的对流速度是这种压力-位移耦合的要紧 。通过对一次登陆飓风的案例探讨,而西西伯利亚更湿润的条件促进了与湿地相关的排放(0.4±0.1 TgCH4·年-2)。最有恐怕用于交联;而在干性粘液类型中 ,粘附、
这些察觉揭示了这些粘弹性材料的多功能性,他们确定了HBL湍流在次声压力和地震位移中的贡献 ,其可以根据钙和蛋白质含量的差异,并将其称之为“亲电穿梭”。探讨组设计了亲电反应性(C–X)从一个碳原子向另一个碳原子的转移 ,
尽管在当前市场条件下,更干燥的条件加剧了与火灾相关的排放(0.7±0.1 TgCH4·年-2),两个相邻碳原子的官能化通常以烯烃或已双取代的前体为起始原料。ACC在湿性粘液类型中可充当离子源