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Nucleophilic trifluoromethylation with CF_(3)H/LiHMDS: probing the nucleophilic reactivity of LiCF_(3) species

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Science China Chemistry 2025年第2期68卷 505-512页

作者： Yangfan Liu xiu wang Chuanfa Ni Jinbo Hu College of Chemistry Central China Normal UniversityWuhan 430079China Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032China

The nucleophilic trifluoromethylation involving trifluoromethyllithium(LiCF_(3))species has been an open question since Haszeldine attempted to prepare LiCF_(3) in ***,LiCF_(3) has been used for electrophilic difluoromethylene transfer processes(via elimination of fluoride ions)since ***,we demonstrated that by using a polar solvent such as dimethylformamide(DMF)or hexamethylphosphoramide(HMPA)as the lithium chelator,the in situ deprotonation of fluoroform(HCF_(3))with lithium hexamethyldisilazide(LiHMDS)could generate a tamed LiCF_(3) species that is sufficiently persistent to undergo nucleophilic trifluoromethylation *** nucleophilic reactivity of LiCF_(3) species was probed with several electrophiles,including arylsulfonyl fluorides,diaryl ketones,and silyl *** synthetic utility of this method is demonstrated with the efficient synthesis of highly valuable triflones that are otherwise difficult to synthesize from HCF_(3) using potassium or sodium *** work not only showcases a new protocol for the utilization of fluoroform(an industrial waste with high global warming potential)as the trifluoromethylation reagent,but also provides intriguing insights into the harnessing of nucleophilic reactivity of the transient LiCF_(3) species.

关键词： nucleophilic trifluoromethylation trifluoromethy llithium fluorinated carbanion negative fluorine effect fluorinated carbenoid

Acoustic wave propagation in a porous medium saturated with two fluids and a solid

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Chinese Physics B 2025年第2期34卷 297-307页

作者： Lin Liu xiu-Mei Zhang xiu-Ming wang State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100149China Beijing Engineering Research Center of Sea Deep Drilling and Exploration Institute of AcousticsChinese Academy of SciencesBeijing 100190China

Wave propagation in multi-phase porous media is a significant research topic. There are a series of studies about porous media saturated with a single fluid, a solid and a fluid, two fluids, and three fluids. Some gas hydrate-bearing sediments are typical multiphase porous media saturated with a solid(gas hydrates) and two fluids(water and gas). Based on existing theories of porous media, we develop a theory and give a comprehensive analysis of wave propagation in a poroelastic medium saturated with two fluids and a solid. Initially, we establish the constitutive relations and equations of motion. Based on Biot's approach for describing the equations of motion in fluid-saturated porous media at the macroscale,the kinetic energy density, potential energy density, and dissipative energy density are derived. After deriving the equations of motion, a plane wave analysis predicts the existence of four compressional waves, denoted P1, P2, P3, and P4 waves,and two shear waves, denoted S1 and S2 waves. Numerical examples are presented to demonstrate how velocities and attenuations of various waves behave with gas saturation, gas hydrate saturation, and frequency. A model degradation to porous media saturated with a single fluid supports the validity of the theory, which enriches the theory of multiphase porous media and provides a foundation for the evaluation of gas hydrate-bearing sediments.

关键词： four-phase porous media equations of motion plan wave analysis wave characteristics

Dark energy effects on surface gravitational redshift and Keplerian frequency of neutron stars

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Communications in Theoretical Physics 2025年第1期77卷 122-129页

作者： Jia-Jing He Yan Xu Yi-Bo wang xiu-Lin Huang Xing-Xing Hu Yu-Fu shen Changchun Observatory National Astronomical ObservatoriesChinese Academy of SciencesChangchun 130117China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China

Research on the properties of neutron stars with dark energy is a particularly interesting yet unresolved problem in *** analyze the influence of dark energy on the equation of state,the maximum mass,the surface gravitational redshift and the Keplerian frequency for the traditional neutron star and the hyperon star matter within the relativistic mean field theory,using the GM1 and TM1 parameter sets by considering the two flavor symmetries of SU(6)and SU(3)combined with the observations of PSR J1614-2230,PSR J0348+0432,PSR J0030+0451,RX J0720.4-3125,and 1E *** is found that the existence of dark energy leads to the softened equations of the state of the traditional neutron star and the hyperon *** radius of a fixed-mass traditional neutron star(or hyperon star)with dark energy becomes smaller,which leads to increased *** existence of dark energy can also enhance the surface gravitational redshift and the Keplerian frequency of traditional neutron stars and hyperon *** growth of the Keplerian frequency may cause the spin rate to speed up,which may provide a possible way to understand and explain the pulsar glitch ***,we infer that the mass and the surface gravitational redshift of PSR J1748-2446ad without dark energy for the GM1(TM1)parameter set are 1.141 M_(☉)(1.309 M_(☉))and 0.095(0.105),*** corresponding values for the GM1(TM1)parameter set are 0.901 M_(☉)(1.072M_(☉))and 0.079(0.091)if PSR J1748-2446ad contains dark energy withα=*** J1748-2446ad may be a low-mass pulsar with a lower surface gravitational redshift under our selected models.

关键词： dark energy neutron stars gravitational redshift Keplerian frequency

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Environmental Inequality in China’s Urban Expansion:A Case Study of Guangzhou,China

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Chinese Geographical Science 2025年第1期35卷 187-202页

作者： wang Shaogu shen Jing School of Geography and Planning Sun Yat-sen UniversityGuangzhou 510006China

Environmental inequality is a prevalent issue in developing countries undergoing urban *** expansion induces the formation and evolution of environmental inequality by creating environmental and structural conditions that lead to the spatial relocation of environmental hazards and the socio-spatial segregation of different groups in developing *** study investigated the spatial patterns and temporal trends of environmental inequality under urban expansion in Guangzhou,a megacity in *** considered how environmental disparities and socio-demographic attributes interact in terms of industrial pollution exposure using additive semiparametric quantile regression,combined with spatial visualisation,on the basis of the economic and population census data from 1990 to *** study revealed that urban expansion sparked the spatial displacement of environmental risks and the social-spatial differentiation,exposing the peripheral regions and disadvantaged groups to higher environmental risks.A reciprocal transformation occurred between central and peripheral regions,as well as a process of redistributing environmental risks across social *** the context of urban expansion in developing countries,the causes of environmental inequality shifted from individual socio-economic differences to structural factors,such as industrial layout and social division of labour in cities,leading to the spatial displacement and concealment of environmental *** study provides insights and guidance for policymakers to address the issue of environmental inequality in the context of urban expansion.

关键词： environmental inequality urban expansion spatiotemporal evolution additive semiparametric quantile regression Guangzhou,China

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PRODUCTION OF LIGHT ALKENES FROM CO AND/OR CO2 HYDROGENATION OVER K-Fe-MnO/SILICALITE-2 CATALYST

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Journal of Energy Chemistry 1995年第2期 167-177页

作者： XU Long-Ya* wang Qing-XiaLIANG Dong-Bai TIAN Zhi-JianYANG Li ZHAO xiu-shen wang Kai-LiDalian Institute of Chemical Physics, Academia Smica Dalian, Ijiaaning 116023

High selectivity to light alkenes can be achieved from CO and COhydrogenation over K-Fe-MnO/Si-2 *** alkene selectivity isinsensitive to reaction temperature for CO hydrogenation,while apparentlyincreases for COhydrogenation with raising reaction *** increasein alkene selectivity is observed for both CO and COhydrogenation with GHSVrising,While a decrease with the elevation of reaction pressure for both CO/Hand CO/Hreaction.A two-step mechanism is suggested forCOhydrogenation to form hydrocarbons,by which the variations incontributions of CO and HC as products of CO/Hreaction with change ofreaction temperature,GHSV and pressure are ***,thecatalyst is favorable for selective production of light olefins,which can alsoconcern the slightly secondary reactions of light olefins to some extent.

关键词： Fe-MnO catalyst silicalite-2 light alkenes carbon monoxide carbon dioxide

Evaluating the accuracy of earth rotation parameters based on the BDS observations

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Geodesy and Geodynamics 2025年第1期16卷 87-98页

作者： Chenxiang wang Pengfei Zhang Tengxu Zhang Ziyu shen Jizhang Sang Wenbin shen School of Geodesy and Geomatics Wuhan University Time and Frequency Geodesy Center Wuhan University School of Resource Environmental Science and Engineering Hubei University of Science and Technology

The Bei Dou satellite system(BDS) has progressed with the full operationalization of the secondgeneration regional system(BDS-2) and the third-generation global system(BDS-3). This technology plays a crucial role in determining Earth Rotation Parameters(ERPs). In this study, we determine the ERPs based on the observations of BDS-2, BDS-3 and BDS-2+BDS-3, with the time spanning from August18, 2022, to August 18, 2023. The IERS EOP 20C04 series is used as a reference to evaluate the accuracy of the ERP estimates. We analyze the impact of different numbers of reference stations, polyhedron volumes, observation arc lengths, satellite types, and satellite systems on solving ERPs using BDS-2 and BDS-3 observation data provided by the International GNSS Service(IGS) stations. When selecting a specific satellite type, it is necessary to choose an appropriate observation arc length based on different numbers of reference stations while maximizing the volume of the formed polyhedron to achieve optimal efficiency and accuracy in parameter estimation. When both the number of reference stations and observation arc length are fixed, higher precision of the ERPs can be achieved using observations from MEO than MEO + IGSO and MEO + IGSO + GEO. Moreover, when considering only IGSO and MEO satellites as options for analysis purposes, BDS-3 provides higher accuracy compared to BDS-2. In summary, when using BDS for ERP estimation and MEO satellite observations with the same observation arc length,selecting stations from reference stations with larger polyhedral volumes can significantly improve the efficiency and accuracy of parameter estimation.

关键词： Earth rotation parameters Polyhedron volume Observation arc length BDS-2 BDS-3

Detection of Perfect Stealthy Attacks on Cyber-Physical Systems Subject to Measurement Quantizations: A Watermark-Based Strategy

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 114-125页

作者： Yu-Ang wang Zidong wang Lei Zou Bo shen Hongli Dong the College of Information Science and Technology Donghua University the Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of Education IEEE the College of Electrical Engineering and Automation Shandong University of Science and Technology the Department of Computer Science Brunel University London Uxbridge the Sanya Offshore Oil and Gas Research Institute Northeast Petroleum University the Artificial Intelligence Energy Research Institute Northeast Petroleum University Heilongjiang Provincial Key Laboratory of Networking and Intelligent Control Northeast Petroleum University

In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are quantized before transmission.A specific type of perfect stealthy attack, which meets certain rather stringent conditions, is taken into account. Such attacks could be injected by adversaries into both the sensor-toestimator and controller-to-actuator channels, with the aim of disrupting the normal data flow. For the purpose of defending against these perfect stealthy attacks, a novel scheme based on watermarks is developed. This scheme includes the injection of watermarks(applied to data prior to quantization) and the recovery of data(implemented before the data reaches the estimator).The watermark-based scheme is designed to be both timevarying and hidden from adversaries through incorporating a time-varying and bounded watermark signal. Subsequently, a watermark-based attack detection strategy is proposed which thoroughly considers the characteristics of perfect stealthy attacks,thereby ensuring that an alarm is activated upon the occurrence of such attacks. An example is provided to demonstrate the efficacy of the proposed mechanism for detecting attacks.

关键词： Attack detection cyber-physical systems (CPSs) perfect stealthy attacks watermark-based strategy

Exit options sustain altruistic punishment and decrease the second-order free-riders, but it is not a panacea

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Science China(Information Sciences) 2025年第1期68卷 278-291页

作者： Chen shen Zhao SONG Lei SHI Jun TANIMOTO Zhen wang Faculty of Engineering Sciences Kyushu University School of Statistics and Mathematics Yunnan University of Finance and Economics School of Computing Engineering and Digital Technologies Teesside University School of Artificial Intelligence OPtics and Electro Nics (iOPEN) Northwestern Polytechnical University

Why do humans punish free riders at their own expense? This behavior represents an evolutionary puzzle in human societies. This study explores the role of exit strategies in fostering altruistic punishment within evolutionary game theory. We extend the traditional prisoner's dilemma model by incorporating exiters, players who opt out for a small payoff while nullifying their opponent's payoff, and altruistic punishers who cooperate and punish non-cooperators. Our findings indicate that in well-mixed populations, exiters destabilize defection but do not promote altruistic punishment. In social networks, however,exiters enable altruistic punishment via cyclic dominance among altruistic punishers, defectors, and exiters. Notably, this cyclic dominance is sensitive to exit payoffs; adjustments can lead to cyclic dominance of non-punishing cooperators, defectors, and exiters, or to a bi-stable state between these two types of cyclic dominance. These results highlight the nuanced impact of exiters on altruistic punishment, emphasizing the need for careful incentivization of exit behavior. While exiters can support altruistic punishment in networked populations, their effectiveness is not a panacea and is highly sensitive to exit payoffs, indicating limits to the voluntary participation mechanism.

关键词： evolutionary game theory altruistic punishment coexistence cyclic dominance bi-stable

Unraveling the exceptional kinetics of Zn‖organic batteries in hydrated deep eutectic solution

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Journal of Energy Chemistry 2025年第2期101卷 570-577页

作者： Duo Chen Yuanhang wang Tengyu Yao Hang Yang Laifa shen Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Christopher Ingold Laboratory Department of Chemistry University College London

Intuitively,the solvation structure featuring stronger interacted sheath in deep eutectic solution（DES）electrolyte would result in sluggish interfacial charge transfer and intense polarization,which obstructs its practical application in emerging Zn based ***,here we discover a Zn‖organic battery with exceptional kinetics properties enabled by a hydrated DES electrolyte,which can render higher discharge capacity,smaller voltage polarization,and faster kinetics of charge transfer in comparison with conventional aqueous 3 M ZnCl2electrolyte,though its viscosity is two orders of magnitude higher than the *** improved kinetics of charge transfer and ion diffusion is demonstrated to originate from the local electron structure regulation of cathode in hydrated DES ***,the DES electrolyte has also been shown to restrict parasitic reaction associated with active water by preferential urea-molecular adsorption on Zn surface and stronger water trapping in solvation structure,giving rise to long-term stable dendrite-free Zn plating/*** work provides a new rationale for understanding electrochemical behaviors of organic cathodes in DES electrolyte,which is conducive to the development of high-performance Zn‖organic batteries.

关键词： Deep eutectic Dendrite-free Kinetics Zn-based battery