作者:未玖 来源:科学网微信公众号 发布时间:2024/4/21 20:21:23
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《科学》(20240419出版)一周论文导读

 

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Science, 19 APR 2024, VOL 384, ISSUE 6693

《科学》2024年4月19日,第384卷,6693期

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天文学Astronomy

Dating the Solar System’s giant planet orbital instability using enstatite meteorites

用顽辉石陨石测定太阳系巨行星轨道不稳定时期

▲ 作者:CHRYSA AVDELLIDOU, MARCO DELBO’, DAVID NESVORNY, KEVIN J. WALSH & ALESSANDRO MORBIDELLI

▲ 链接:

https://www.science.org/doi/10.1126/science.adg8092

▲ 摘要:

太阳系的巨行星最初在紧凑轨道上形成,由于轨道不稳定过渡至目前更宽的结构。这种不稳定发生的时机很难确定。

研究组使用动力学模拟来证明轨道不稳定将类地行星区域的星子碎片植入小行星主带。使用陨石数据表明,植入发生在太阳系诞生后超6000万年。

将这一约束条件与先前从木星特洛伊小行星中得出的上限相结合,研究组得出结论,轨道不稳定发生在太阳系诞生后6000万年至1亿年。形成月球的巨大撞击发生在该时期,因此其可能与巨行星不稳定有关。

▲ Abstract:

The giant planets of the Solar System formed on initially compact orbits, which transitioned to the current wider configuration by means of an orbital instability. The timing of that instability is poorly constrained. In this work, we use dynamical simulations to demonstrate that the instability implanted planetesimal fragments from the terrestrial planet region into the asteroid main belt. We use meteorite data to show that the implantation occurred >60 million years (Myr) after the Solar System began to form. Combining this constraint with a previous upper limit derived from Jupiter’s trojan asteroids, we conclude that the orbital instability occurred 60 to 100 Myr after the beginning of Solar System formation. The giant impact that formed the Moon occurred within this range, so it might be related to the giant planet instability.

材料科学Materials Science

Structural disorder determines capacitance in nanoporous carbons

结构无序决定了纳米多孔碳的电容

▲ 作者:XINYU LIU, DONGXUN LYU, CéLINE MERLET, MATTHEW J. A. LEESMITH, XIAO HUA, ZHEN XU, ET AL.

▲ 链接:

https://www.science.org/doi/10.1126/science.adn6242

▲ 摘要:

纳米多孔碳电极复杂结构的表征困难导致缺乏明确的设计原则来改进超级电容器。孔径尺寸一直被认为是提高电容的主要杠杆。

然而,研究组对大量商业纳米多孔碳的评估发现孔径和电容之间缺乏相关性。相反,核磁共振波谱测量和模拟揭示了电极结构无序和电容之间的强烈相关性。

具有更小的类石墨烯结构域的无序碳因在其纳米孔中更有效地存储离子,从而表现出更高的电容。该发现提出了理解和利用无序来实现高能量密度超级电容器的方法。

▲ Abstract:

The difficulty in characterizing the complex structures of nanoporous carbon electrodes has led to a lack of clear design principles with which to improve supercapacitors. Pore size has long been considered the main lever to improve capacitance. However, our evaluation of a large series of commercial nanoporous carbons finds a lack of correlation between pore size and capacitance. Instead, nuclear magnetic resonance spectroscopy measurements and simulations reveal a strong correlation between structural disorder in the electrodes and capacitance. More disordered carbons with smaller graphene-like domains show higher capacitances owing to the more efficient storage of ions in their nanopores. Our findings suggest ways to understand and exploit disorder to achieve highly energy-dense supercapacitors.

High energy density in artificial heterostructures through relaxation time modulation

通过弛豫时间调制实现人工异质结构的高能量密度

▲ 作者:SANGMOON HAN, JUSTIN S. KIM, EUGENE PARK, YUAN MENG, ZHIHAO XU, ALEXANDRE C. FOUCHER, ET AL.

▲ 链接:

https://www.science.org/doi/10.1126/science.adl2835

▲ 摘要:

静电电容器因其超快的充放电能力成为先进电子器件和大功率电气系统的基础元件。铁电材料具有较高的最大极化,但高残余极化阻碍了其在储能应用中的有效部署。先前方法由于铁电材料结晶度退化而遭遇瓶颈。

研究组介绍了一种利用二维(2D)材料控制弛豫时间的方法,同时通过使用2D/3D/2D异质结构来最小化能量损失,并保持铁电3D材料的结晶度。使用该方法可实现191.7 J/cm3的能量密度,效率超过90%。

这种对弛豫时间的精确控制有望促进广泛应用,并有潜力加速高效储能系统的发展。

▲ Abstract:

Electrostatic capacitors are foundational components of advanced electronics and high-power electrical systems owing to their ultrafast charging-discharging capability. Ferroelectric materials offer high maximum polarization, but high remnant polarization has hindered their effective deployment in energy storage applications. Previous methodologies have encountered problems because of the deteriorated crystallinity of the ferroelectric materials. We introduce an approach to control the relaxation time using two-dimensional (2D) materials while minimizing energy loss by using 2D/3D/2D heterostructures and preserving the crystallinity of ferroelectric 3D materials. Using this approach, we were able to achieve an energy density of 191.7 joules per cubic centimeter with an efficiency greater than 90%. This precise control over relaxation time holds promise for a wide array of applications and has the potential to accelerate the development of highly efficient energy storage systems.

More resilient polyester membranes for high-performance reverse osmosis desalination

恢复力更强的聚酯膜助力高性能反渗透海水淡化

▲ 作者:YUJIAN YAO, PINGXIA ZHANG, FEI SUN, WEN ZHANG, MENG LI, GANG SHA, ET AL.

▲ 链接:

https://www.science.org/doi/10.1126/science.adk0632

▲ 摘要:

近半个世纪以来,薄膜复合反渗透膜一直是海水淡化和水净化的黄金标准技术。聚酰胺膜具有优异的透水性和拒盐性,但也有耐氯性差、结垢倾向高和拒硼率低的缺点。

研究组通过分子设计聚酯膜复合反渗透膜来解决这些问题,使用共溶剂辅助界面聚合法使3,5-二羟基-4-甲基苯甲酸与均苯三甲酰氯反应。这种聚酯膜具有优异的透水性,对氯化钠和硼高截留,以及完全耐氯。

与聚酰胺膜相比,该膜的超光滑、低能量表面还可防止污垢和矿物结垢。通过进一步优化水盐选择性,该膜有望超越聚酰胺膜,为大大减少海水淡化的预处理步骤提供新途径。

▲ Abstract:

Thin-film composite reverse osmosis membranes have remained the gold standard technology for desalination and water purification for nearly half a century. Polyamide films offer excellent water permeability and salt rejection but also suffer from poor chlorine resistance, high fouling propensity, and low boron rejection. We addressed these issues by molecularly designing a polyester thin-film composite reverse osmosis membrane using co-solvent–assisted interfacial polymerization to react 3,5-dihydroxy-4-methylbenzoic acid with trimesoyl chloride. This polyester membrane exhibits substantial water permeability, high rejection for sodium chloride and boron, and complete resistance toward chlorine. The ultrasmooth, low-energy surface of the membrane also prevents fouling and mineral scaling compared with polyamide membranes. These membranes could increasingly challenge polyamide membranes by further optimizing water-salt selectivity, offering a path to considerably reducing pretreatment steps in desalination.

人工智能Artificial Intelligence

Fusion of memristor and digital compute-in-memory processing for energy-efficient edge computing

融合忆阻器和数字内存计算处理助力高效边缘计算

▲ 作者:TAI-HAO WEN, JE-MIN HUNG, WEI-HSING HUANG, CHUAN-JIA JHANG, YUN-CHEN LO, HUNG-HSI HSU, ET AL.

▲ 链接:

https://www.science.org/doi/10.1126/science.adf5538

▲ 摘要:

人工智能(AI)边缘设备更倾向于采用高容量非易失性内存计算(CIM)来实现高能效和足够准确的快速唤醒响应。大多数先前的工作要么依据基于忆阻器的CIM,但因其耐用性有限而遭受精度损失且不支持训练;要么依据数字静态随机存取存储器(SRAM)的CIM,但受限于大面积制造需求和易失性存储。

研究组报道了一种使用忆阻器-SRAM CIM融合方案的AI边缘处理器,可同时利用数字SRAM CIM的高精度和电阻式随机存取存储器忆阻器CIM的高能效和存储密度。这也使自适应本地训练能够适应个性化特征和用户环境。

该融合处理器实现了高CIM容量、短唤醒-响应延迟(392微秒)、高峰值能效(77.64 TOPS/W)和稳健的精度(精度损失<0.5%)。这项工作表明,忆阻器技术已经超越了实验室开发阶段,现已具备用于AI边缘处理器的可制造性。

▲ Abstract:

Artificial intelligence (AI) edge devices prefer employing high-capacity nonvolatile compute-in-memory (CIM) to achieve high energy efficiency and rapid wakeup-to-response with sufficient accuracy. Most previous works are based on either memristor-based CIMs, which suffer from accuracy loss and do not support training as a result of limited endurance, or digital static random-access memory (SRAM)–based CIMs, which suffer from large area requirements and volatile storage. We report an AI edge processor that uses a memristor-SRAM CIM-fusion scheme to simultaneously exploit the high accuracy of the digital SRAM CIM and the high energy-efficiency and storage density of the resistive random-access memory memristor CIM. This also enables adaptive local training to accommodate personalized characterization and user environment. The fusion processor achieved high CIM capacity, short wakeup-to-response latency (392 microseconds), high peak energy efficiency (77.64 teraoperations per second per watt), and robust accuracy (<0.5% accuracy loss). This work demonstrates that memristor technology has moved beyond in-lab development stages and now has manufacturability for AI edge processors.

地球科学Earth Science

A national-scale assessment of land subsidence in China’s major cities

中国主要城市地面沉降的全国范围评估

▲ 作者:ZURUI AO, XIAOMEI HU, SHENGLI TAO, XIE HU, GUOQUAN WANG, MINGJIA LI, ET AL.

▲ 链接:

https://www.science.org/doi/10.1126/science.adl4366

▲ 摘要:

中国大规模的城市化浪潮可能会受到地面沉降的威胁。

利用星载干涉合成孔径雷达测量技术,研究组对2015—2022年中国主要城市的地面沉降进行了系统评估。在被调查的城市土地中,45%的土地每年沉降速度超过3毫米,16%的土地每年沉降速度超过10毫米,分别影响了29%和7%的城市人口。

沉降似乎与地下水抽取和建筑物重量等一系列因素有关。到2120年,由于城市沉降和海平面上升的综合影响,22%~26%中国沿海土地的相对海拔将低于海平面,占沿海人口的9%~11%。

该研究结果强调了加强保护措施以减轻沉降造成潜在损害的必要性。

▲ Abstract:

China’s massive wave of urbanization may be threatened by land subsidence. Using a spaceborne synthetic aperture radar interferometry technique, we provided a systematic assessment of land subsidence in all of China’s major cities from 2015 to 2022. Of the examined urban lands, 45% are subsiding faster than 3 millimeters per year, and 16% are subsiding faster than 10 millimeters per year, affecting 29 and 7% of the urban population, respectively. The subsidence appears to be associated with a range of factors such as groundwater withdrawal and the weight of buildings. By 2120, 22 to 26% of China’s coastal lands will have a relative elevation lower than sea level, hosting 9 to 11% of the coastal population, because of the combined effect of city subsidence and sea-level rise. Our results underscore the necessity of enhancing protective measures to mitigate potential damages from subsidence.

 
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