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Heterostructure:application of absorption-catalytic center in lithium-sulfur batteries

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Rare Metals 2024年第4期43卷 1461-1487页

作者： Fei Wang Chun-Man Yang Yong-Qi Wang Dan You Wen-Hao Yang Rong-Wei Huang Ji-Yue Hou Qian Wang Ying-Jie Zhang Ying Wang Yue-Jing Zeng Yi-Yong Zhang Xue Li National Local joint Engineering Research center for Lithium-Ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Batteries Materials of Yunnan ProvinceFaculty of Metallurgical and Energy Engineering Kunming University of Science and Technology College of Electrical Information Engineering Panzhihua University State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Centre of Chemistry for Energy MaterialsState-Province Joint Engineering Laboratory of Power Source Technology for New Energy VehicleEngineering Research Center of Electrochemical TechnologyMinistry of EducationCollege of Chemistry and Chemical Engineering Xiamen University

Due to the high theoretical specific capacity(1675 mAh·g-1),low cost,and high safety of the sulfur cathodes,they are expected to be one of the most promising rivals for a new generation of energy storage systems.However,the shuttle effect,low conductivity of sulfur and its discharge products,volume expansion,and other factors hinder the commercialization of lithium-sulfur batteries（LSBs）.The development of sulfur-fixing materials and the design of multifunctional materials to enhance the electrochemical performance of LSBs have been the main research priorities in recent years.Because of the advantages of high conductivity,built-in electric field,and good synergism,more and more researchers have employed heterostructure into sulfur-fixing materials to enhance the catalytic and absorption ability for polysulfides.In this review,the principle of heterostructure and the mechanism of enhancing the performance of lithium-sulfur batteries are described.The applications of heterostructure in cathode and interlayer of LSBs in the latest years are summarized.Finally,the cutting-edge troubles and possibilities of heterostructures in LSBs are briefly presented.

关键词： Lithium–sulfur batteries (LSBs) Heterostructure Built-in electric field Catalytic Absorption

A phase separation-fortified bi-specific adaptor for conditional tumor killing

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Science China(Life Sciences) 2024年第7期67卷 1385-1397页

作者： Yuyan Liu Yuting Zhu Weifan Xu Pilong Li State Key Laboratory of Membrane Biology Frontier Research Center for Biological StructureTsinghua University-Peking University Joint Center for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing 100084China

A common approach in therapeutic protein development involves employing synthetic ligands with multivalency,enabling sophisticated control of signal transduction.Leveraging the emerging concept of liquid-liquid phase separation(LLPS)and its ability to organize cell surface receptors into functional compartments,we herein have designed modular ligands with phase-separation modalities to engineer programmable interreceptor communications and precise control of signal pathways,thus inducing the rapid,potent,and specific apoptosis of tumor cells.Despite their simplicity,these“triggers”,named phase-separated Tumor Killers(hereafter referred to as psTK),are sufficient to yield interreceptor clustering of death receptors(represented by DR5)and tumor-associated receptors,with notable features:LLPSmediated robust high-order organization,well-choreographed conditional activation,and broad-spectrum capacity to potently induce apoptosis in tumor cells.The development of novel therapeutic proteins with phase-separation modalities showcases the power of spatially reorganizing signal transduction.This approach facilitates the diversification of cell fate and holds promising potential for targeted therapies against challenging tumors.

关键词： phase separation therapeutic proteins receptor-ligand interactions DR5 tumor apoptosis

Long-term Integration Ability of the Submillimeter Wave Astronomy Satellite (SWAS) Spectral Line Receivers

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Research in Astronomy and astrophysics 2024年第6期24卷 317-324页

作者： Bing-Ru Wang Di Li Paul F.Goldsmith Jingwen Wu Chao-Wei Tsai Rudolf Schieder Gary J.Melnick National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences Research center for Astronomical Computing Zhejiang Laboratory Jet Propulsion Laboratory California Institute of Technology Institute for Frontiers in Astronomy and astrophysics Beijing Normal University KOSMA I.Physik.Institut Universit?t zu K?ln center for astrophysics | Harvard & Smithsonian

The Submillimeter Wave Astronomy Satellite（SWAS） was the first space telescope capable of high spectral resolution observations of terahertz spectral lines. We have investigated the integration ability of its two receivers and spectrometer during five and a half years of on-orbit operation. The CI, O2, H2O, and13CO spectra taken toward all observed Galactic sources were analyzed. The present results are based on spectra with a total integration time of up to 2.72 × 10～4hr（■10～8s）. The noise in the spectra is generally consistent with that expected from the radiometer equation, without any sign of approaching a noise floor. This noise performance reflects the extremely stable performance of the passively cooled front end as well as other relevant components in the SWAS instrument throughout its mission lifetime.

关键词： instrumentation: miscellaneous ISM: lines and bands space vehicles: instruments telescopes

Nickel-Catalyzed Regiodivergent Acylzincation of Styrenes with Organozincs and CO

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Chinese Journal of Chemistry 2024年第6期42卷 599-604页

作者： Chenglong Wang Ning Liu Xianqing Wu Jingping Qu Yifeng Chen Key Laboratory for Advanced Materials and joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CenterFrontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237 China Dedicated to the Special Issue of C1 Chemistry.

Transition metal-catalyzed carbometallation of unsaturated hydrocarbons constitutes one of the most efficient synthetic methodologies for the construction of C—C bond.Recently,the incorporation of organometallic reagent with the CO gas as a nucleophilic acyl synthon could enable the acylmetallation reaction,which greatly increases the horizon of carbometallation chemistry.Herein,we report a nickel-catalyzed regiodivergent acylzincation of o-cyano cinnamate ester and o-cyano styrene,in which the cyano moiety intramolecularly captures zinc intermediates to trigger the tandem cyclization process.This protocol features mild conditions,broad substrate scope and excellent functional group tolerance,thus affording a diverse array of highly functionalized carbocyclic compounds.

关键词： Carbonylation Carbometallation Styrene Nickel Cyclization

Remote copper-catalyzed enantioselective substitution of yne-thiophene carbonates

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Science China Chemistry 2024年第4期67卷 1175-1180页

作者： Hao-Dong Qian Xiang Li Tingrui Yin Wei-Feng Qian Chunhui Zhao Cuiju Zhu Hao Xu CCNU-uOttawa joint Research Centre Key Laboratory of Pesticides&Chemical Biology of Ministry of EducationInternational Joint Research Center for Intelligent Biosensing Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan 430079China

Here,we describe a strategy for the copper-catalyzed asymmetric heteroarylation of yne-thiophene carbonates with indoles via remote substitution.The key to the success of this strategy lies in the design of the alkynyl group at the ortho-position of the heterocycle thiophene,enabling the formation of a triarylmethane moiety via very remote substitution.Thus,the concept of remote copper-catalyzed asymmetric transformation extends not only to yne-allylic esters but also to yne-aryl esters.The reaction readily provides a diverse array of chiral triarylmethanes with high efficiency,enantioselectivity,and excellent functional group compatibility.Moreover,facile follow-up transformations underscore their potential utility in the synthesis of various enantioenriched building blocks.Preliminary mechanistic studies support the plausibility of the remote substitution pathway.

关键词： remote substitution copper catalyst asymmetric catalysis triaryl methanes

Understanding adversarial attacks on observations in deep reinforcement learning

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Science China(Information Sciences) 2024年第5期67卷 69-83页

作者： You QIAOBEN Chengyang YING Xinning ZHOU Hang SU Jun ZHU Bo ZHANG Department of Computer Science and Technology Beijing National Research Center for Information Science and Technology Tsinghua-Bosch Joint Center for Machine Learning Institute for Artificial Intelligence Tsinghua University Peng Cheng Laboratory

Deep reinforcement learning models are vulnerable to adversarial attacks that can decrease the cumulative expected reward of a victim by manipulating its observations. Despite the efficiency of previous optimization-based methods for generating adversarial noise in supervised learning, such methods might not achieve the lowest cumulative reward since they do not generally explore the environmental dynamics.Herein, a framework is provided to better understand the existing methods by reformulating the problem of adversarial attacks on reinforcement learning in the function space. The reformulation approach adopted herein generates an optimal adversary in the function space of targeted attacks, repelling them via a generic two-stage framework. In the first stage, a deceptive policy is trained by hacking the environment and discovering a set of trajectories routing to the lowest reward or the worst-case performance. Next, the adversary misleads the victim to imitate the deceptive policy by perturbing the observations. Compared to existing approaches, it is theoretically shown that our adversary is strong under an appropriate noise level. Extensive experiments demonstrate the superiority of the proposed method in terms of efficiency and effectiveness, achieving state-of-the-art performance in both Atari and MuJoCo environments.

关键词： deep learning reinforcement learning adversarial robustness adversarial attack

The Influence of the Sun and Moon on the Observation of Very High Energy Gamma-ray Sources Using EAS Arrays

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Research in Astronomy and astrophysics 2024年第6期24卷 247-254页

作者： Tao Wen Songzhan Chen Benzhong Dai School of Physics and Astronomy Yunnan University Key Laboratory of Particle astrophysics Institute of High Energy Physics Chinese Academy of Sciences Tianfu Cosmic Ray Research center

With great advance of ground-based extensive air shower arrays, such as LHAASO and HAWC, many very high energy(VHE) gamma-ray sources have been discovered and are being monitored regardless of the day and the night. Hence, the Sun and Moon would have some impacts on the observation of gamma-ray sources, which have not been taken into account in previous analysis. In this paper, the influence of the Sun and Moon on the observation of very high energy gamma-ray sources when they are near the line of sight of the Sun or Moon is estimated. The tracks of all the known VHE sources are scanned and several VHE sources are found to be very close to the line of sight of the Sun or Moon during some period. The absorption of very high energy gamma rays by sunlight is estimated with detailed method and some useful conclusions are achieved. The main influence is the block of the Sun and Moon on gamma rays and the shadow on the cosmic ray background. The influence is investigated considering the detector angular resolution and some strategies on data analysis are proposed to avoid the underestimation of the gamma-ray emission.

关键词： astroparticle physics methods: observational Sun: general Sun: UV radiation

EP Aquarii:A New Picture of the Circumstellar Envelope

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Research in Astronomy and astrophysics 2024年第3期24卷 83-105页

作者： Pham T.Nhung Do T.Hoai Pierre Darriulat Pham Tuan-Anh Pham N.Diep Nguyen B.Ngoc Tran T.Thai Department of astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar envelope.The birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been obtained.Close to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the equator.It implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is difficult.In particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at an angular distance of -0″4 from its center.It proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its wake.High Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

Probing the Gamma-Ray Emission Region of Five TeV Flat Spectrum Radio Quasars

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Research in Astronomy and astrophysics 2024年第6期24卷 158-171页

作者： Hu-Bing Xiao Hai-Tao Cao Rui Xue Jin-Ting Cai Ge-Ge Wang Marina Manganaro shao-Hua Zhang Zhi-Hao Ouyang Li-Ping Fu Jun-Hui Fan Shanghai Key Lab for astrophysics Shanghai Normal University School of Information Engineering Department of Physics Zhejiang Normal University College of Mathematics and Physics Guangxi Minzu University Key Laboratory of Cosmology and astrophysics (Liaoning) College of Sciences Northeastern University Department of Physics University of Rijeka center for astrophysics Guangzhou University Key Laboratory for Astronomical Observation and Technology of Guangzhou Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province

The location of γ-ray emission of blazars remains a contested topic, inspiring the development of numerous investigative techniques to address this issue. In this work, we analyzed Fermi γ-ray light curves in the GeV and MeV bands, employing the discrete cross-correlation function method to discern time lags between the two bands.For 4C +21.35, Ton 599, B2 1420+32, and PKS 1510-089, we identified a time lag spanning several days, while for PKS 1441+25, the time lag was not statistically found. The results imply that the soft photons necessary for inverse Compton scattering predominantly originate from the dusty torus in the first four sources, whereas for PKS1441+25, they seem to be sourced mainly from the broad-line region. Further analysis of the opacity(τγγ) and the GeV spectra study supports the conclusion that the location of the dissipation region must be beyond the BLR to avoid significant absorption. Notably, for PKS 1441+25, the emission region is also posited to lie outside yet proximate to the BLR. The parameters of describing the emission region were obtained by fitting broadband spectral energy distribution with contemporaneous observation data. Our findings suggest that for the five TeV FSRQs, during Te V flaring events, the jet appears to maintain an equilibrium between the energy density of the magnetic field and that of the particles for all investigated sources, with the exceptions of 4C +21.35 and PKS1441+25. In terms of the overall jet power, particle energy is the dominant contributor, and the observed blazar radiation cannot be solely attributed to the magnetic field, except in the case of 4C +21.35. Consequently,magnetic reconnection is unlikely to be the primary mechanism behind particle acceleration in these systems.

关键词： galaxies: active galaxies: jets gamma-rays: galaxies