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发布日期：2024-09-15 作者：开云
Science,12 JUL 2024, VOL 385, ISSUE 6705
《科学》2024年7月12日，第385卷，6705期
物理学Physics
Structured electrons with chiral mass and charge
具有手性质量和电荷的布局电子
▲ 作者：YIQI FANG, JOEL KUTTRUFF, DAVID NABBEN, AND PETER BAUM
▲链接：
https://www.science.org/doi/10.1126/science.adp9143
▲摘要：
手性是一种在根本物理学、材料科学、化学、光学和光谱学中具有普遍联系关系的现象。
这项工作中，研究组证实了自由电子可经由过程激光场周期转化为质量和电荷的右旋或左旋。与相位涡旋光束比拟，该电子连结了平展的德布罗意波，但从当时空期望值的外形取得了响应的手性。
经由过程阿秒门控丈量波函数密度，揭露了具有左旋或右旋螺距的线圈和双线圈的三维外形。具有此类或相干手性几何布局的工程根基粒子可利用在手性传感、自由电子量子光学、粒子物理学或电子显微镜等范畴。
▲ Abstract：
Chirality is a phenomenon with widespread relevance in fundamental physics, material science, chemistry, optics, and spectroscopy. In this work, we show that a free electron can be converted by the field cycles of laser light into a right-handed or left-handed coil of mass and charge. In contrast to phase-vortex beams, our electrons maintained a flat de Broglie wave but obtained their chirality from the shape of their expectation value in space and time. Measurements of wave function densities by attosecond gating revealed the three-dimensional shape of coils and double coils with left-handed or right-handed pitch. Engineered elementary particles with such or related chiral geometries should be useful for applications in chiral sensing, free-electron quantum optics, particle physics or electron microscopy.
材料科学Materials Science
A crystal capping layer for formation of black-phase FAPbI3 perovskite in humid air
在湿润空气中构成黑相FAPbI3钙钛矿的晶体笼盖层
▲ 作者：YU ZOU, WENJIN YU, HAOQING GUO, QIZHI LI, XIANGDONG LI, LIANG LI, ET AL.
▲链接：
https://www.science.org/doi/10.1126/science.adn9646
▲摘要：
黑相甲脒碘化铅（α-FAPbI3）钙钛矿是光伏利用的抱负相，但水会激发诸如δ-FAPbI3光惰性杂质相的构成。
研究组注解，钙钛矿制造的经典溶剂系统加重了这类可反复性挑战。传统配位溶剂二甲亚砜（DMSO）因其吸湿性，在高相对湿度（RH）前提下增进了δ-FAPbI3的构成。
研究组引入含氯有机份子来构成笼盖层，禁止水份渗入，同时保存基在DMSO的共同物来调理晶体发展。所得钙钛矿太阳能电池在20%至60% RH下的能量转换效力 24.5%，在80% RH下为23.4%。在最年夜功率点运行500小时后，未封装装备在空气中（40至60% RH）仍保存96%的初始机能。
▲ Abstract：
Black-phase formamidinium lead iodide (α-FAPbI3) perovskites are the desired phase for photovoltaic applications, but water can trigger formation of photoinactive impurity phases such as δ-FAPbI3. We show that the classic solvent system for perovskite fabrication exacerbates this reproducibility challenge. The conventional coordinative solvent dimethyl sulfoxide (DMSO) promoted δ-FAPbI3 formation under high relative humidity (RH) conditions because of its hygroscopic nature. We introduced chlorine-containing organic molecules to form a capping layer that blocked moisture penetration while preserving DMSO-based complexes to regulate crystal growth. We report power conversion efficiencies of 24.5% for perovskite solar cells fabricated across an RH range of 20 to 60%, and 23.4% at 80% RH. The unencapsulated device retained 96% of its initial performance in air (with 40 to 60% RH) after 500-hour maximum power point operation.
Partitioning polar-slush strategy in relaxors leads to large energy-storage capability
弛豫器的极性雪泥态区块化策略可实现年夜储能容量
▲ 作者：LIANG SHU, XIAOMING SHI, XIN ZHANG, ZIQI YANG, WEI LI, YUNPENG MA, ET AL.
▲链接：
https://www.science.org/doi/10.1126/science.adn8721
▲摘要：
弛豫铁电（RFE）薄膜因其高能量密度（Ue）和高效力而成为小型化高功率电子系统很有前景的储能候选材料。但是，将其Ue提高到200 J/cm3焦耳以上颇具挑战性，这限制了RFE鄙人一代储能装备中的利用潜力。
研究组在RFE中实行了一种极性雪泥态区块化策略来冲破Ue的边界。在相场摹拟的指点下，经由过程按捺非极性立方矩阵和引入高绝缘收集，设计并制备了具有隔离极性雪泥态团簇的Bi(Mg0.5Ti0.5)O3-SrTiO3基高机能RFE薄膜。
可逆极化和击穿强度的同时加强致使Ue到达202 J/cm3，效力高达79%。该策略为下一代高机能电介质供给了设计自由度。
▲ Abstract：
Relaxor ferroelectric (RFE) films are promising energy-storage candidates for miniaturizing high-power electronic systems, which is credited to their high energy density (Ue) and efficiency. However, advancing their Ue beyond 200 joules per cubic centimeter is challenging, limiting their potential for next-generation energy-storage devices. We implemented a parti开云体育apptioning polar-slush strategy in RFEs to push the boundary of Ue. Guided by phase-field simulations, we designed and fabricated high-performance Bi(Mg0.5Ti0.5)O3-SrTiO3–based RFE films with isolated slush-like polar clusters, which were realized through suppression of the nonpolar cubic matrix and introduction of highly insulating networks. The simultaneous enhancement of the reversible polarization and breakdown strength leads to a Ue of 202 joules per cubic centimeter with a high efficiency of ~79%. The proposed strategy provides a design freedom for next-generation high-performance dielectrics.
化学Chemistry
Resetting tropospheric OH and CH4 lifetime with ultraviolet H2O absorption
操纵紫外水接收重设对流层OH和CH4寿命
▲ 作者：MICHAEL J. PRATHER AND LEI ZHU
▲链接：
https://www.science.org/doi/10.1126/science.adn0415
▲摘要：
甲基氯仿（一种禁用的耗损臭氧物资）的衰变供给了对流层羟基自由基（OH）平均品貌的明白不雅测指标。几近所有当前的全球化学模子都计较出约15%的OH过量，从而致使甲烷损掉过快。甲烷是一种短暂的天气因子，对实现全球变暖方针相当主要，这一毛病影响了人们对天气转变的模子猜测。
研究组对紫外线区（290至350纳米）水汽接收的新不雅测注解，近地表热带年夜气中的要害光解速度降落了8%至12%，致使阳光削减。化学输运模子中纳入这一新机制仅能削减4%的OH和甲烷损掉，但连系其他提出的机制，如对流层卤素化学（7%），研究组有望解决这一困难。
▲ Abstract：
The decay of methyl chloroform, a banned ozone-depleting substance, has provided a clear observational metric of mean tropospheric hydroxyl radical (OH) abundance. Almost all current global chemistry models calculate about 15% too much OH and thus too rapid methane loss. Methane is a short-lived climate forcer, critical to achieving global warming targets, and this error affects our model projections of climate change. New observations of water vapor absorption in the ultraviolet region (290 to 350 nanometers) imply reductions in sunlight with key photolysis rates decreasing by 8 to 12% in the near-surface tropical atmosphere. Incorporation of this new mechanism in a chemistry-transport model reduces OH and methane loss by only 4%, but combined with other proposed mechanisms, such as tropospheric halogen chemistry (7%), we may be able to resolve this conundrum.
Programmed alternating current optimization of Cu-catalyzed C-H bond transformations
铜催化C-H键转化的可编程交换电优化
▲ 作者：LI ZENG, QINGHONG YANG, JIANXING WANG, XIN WANG, PENGJIE WANG, SHENGCHUN WANG, ET AL.
▲链接：
https://www.science.org/doi/10.1126/science.ado0875
▲摘要：
直流（DC）电合成手艺在曩昔一个世纪里履历了不竭的优化，在各类工业工艺中起着举足轻重的感化。交换（AC）电合成具有极性反转和周期性波动的特点，或有益在多种化学反映，但装备、道理和利用场景进展较慢。
在这项工作中，研究组介绍了一种可编程交换（pAC）电合成和谈，可系统地调剂电流、频率和占空比。代表性pAC波形的利用增进了在DC和化学氧化前提下表示欠安的交叉偶联和双官能化反映中的铜催化碳-氢键裂解。
另外，不雅察分歧波形利用下的催化剂动态转变为人们供给了机理看法。
▲ Abstract：
Direct current (DC) electrosynthesis, which has undergone optimization over the past century, plays a pivotal role in a variety of industrial processes. Alternating current (AC) electrosynthesis, characterized by polarity reversal and periodic fluctuations, may be advantageous for multiple chemical reactions, but apparatus, principles, and application scenarios remain underdeveloped. In this work, we introduce a protocol for programmed AC (pAC) electrosynthesis that systematically adjusts currents, frequencies, and duty ratios. The application of representative pAC waveforms facilitates copper-catalyzed carbon-hydrogen bond cleavage in cross-coupling and difunctionalization reactions that exhibit suboptimal performance under DC and chemical oxidation conditions. Moreover, observing catalyst dynamic variation under diverse waveform applications provides mechanistic insight.
地球科学Earth Science
Stratospheric air intrusions promote global-scale new particle formation
平流层空气流入增进全球标准新粒子的构成
▲ 作者：JIAOSHI ZHANG, XIANDA GONG, EWAN CROSBIE, GLENN DISKIN, KARL FROYD, SAMUEL HALL, ET AL.
▲链接：
https://www.science.org/doi/10.1126/science.adn2961
▲摘要：
自由对流层中新粒子的构成是全球云凝聚核的首要来历。主流不雅点认为，在自由对流层中，新粒子首要在对流云外流中构成。
研究组操纵全球不雅测提出了另外一种机制。成果发现，在平流层空气流入事务中，降落且富含臭氧的平流层空气与更潮湿的自由对流层布景夹杂致使羟基自由基（OH）浓度升高。
这类夹杂在对流层顶四周最为遍及，那边二氧化硫（SO2）的夹杂比率较高。SO2和OH程度配合升高致使硫酸浓度升高，增进颗粒构成。这类新粒子的构成频率高，地舆散布规模广，是中纬度自由对流层的主要粒子来历。
▲ Abstract：
New particle formation in the free troposphere is a major source of cloud condensation nuclei globally. The prevailing view is that in the free troposphere, new particles are formed predominantly in convective cloud outflows. We present another mechanism using global observations. We find that during stratospheric air intrusion events, the mixing of descending ozone-rich stratospheric air with more moist free tropospheric background results in elevated hydroxyl radical (OH) concentrations. Such mixing is most prevalent near the tropopause where the sulfur dioxide (SO2) mixing ratios are high. The combination of elevated SO2 and OH levels leads to enhanced sulfuric acid concentrations, promoting particle formation. Such new particle formation occurs frequently and over large geographic regions, representing an important particle source in the midlatitude free troposphere.
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