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Asymmetric reversible structural switching of a diene coordination polymer promoted by UV-visible light

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Science China Chemistry 2024年第2期67卷 536-541页

作者： yong wang Qiaoqiao Zhang yong-yong Cao Qi Liu Brendan F.Abrahams Jian-Ping Lang College of Chemistry Chemical Engineering and MaterialsSoochow UniversitySuzhou215123China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing314001China School of Chemistry University of MelbourneVictoria3010Australia

In natural and artificial systems,reversible reactions are commonly asymmetric with respect to the time scale and nature of the stimuli which drive the forward and backward *** applications for which switching behavior is required,it is desirable that the reversible reaction goes as close to symmetric as possible;however,such systems are ***,we report an example of ultraviolet(UV)-visible light-regulated asymmetric reversible structural switching involving a diene-based coordination polymer,CP1 and its monocyclobutane product,*** is possible to cycle at least ten times through a forward [2+2] photocycloaddition reaction and the reverse,photocleavage reaction.A single cycle can be completed within a few *** transformation is accompanied by fast and distinct fluorescence changes,arising from optimisation of the reaction *** functional theory calculations allow rationalisation of the asymmetric reversible transformation between CP1 and CP1a rather than between CP1 and its dicyclobutane product *** work provides a clear illustration of reversible structural switching which approaches symmetric behaviour with respect to reaction rate and *** insights gained from this work also assist in the design of fast,reversible switching materials.

关键词： asymmetrical reversible structural switching coordination polymer photocycloaddition UV-visible light-controlled fluorescence switching

Spatial covariant gravity with two degrees of freedom in the presence of an auxiliary scalar field:Perturbation analysis

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Chinese Physics C 2024年第8期48卷 198-212页

作者： zhi-Chao wang Xian Gao School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China

We investigate a class of gravity theories respecting only spatial covariance,termed spatially covariant gravity,in the presence of an auxiliary scalar *** examine the conditions on the Lagrangian required to eliminate scalar degrees of freedom,allowing only two tensorial degrees of freedom to *** of strict constraint analysis,in this paper,we employ the perturbation method and focus on the necessary conditions to evade the scalar mode at the linear order in perturbations around a cosmological *** with a general action and solving the auxiliary perturbation variables in terms of a would-be dynamical scalar mode,we derive the condition to remove its kinetic term,thus ensuring that no scalar mode *** an application of the general condition,we study a polynomial-type Lagrangian as a concrete example,in which all monomials are spatially covariant scalars containing two *** find that the auxiliary scalar field is essential,and new terms in the Lagrangian are *** analysis provides insights into constructing gravity theories with two degrees of freedom in the extended framework of spatially covariant gravity.

关键词： modified gravity cosmological perturbation theory gravitational theory

Modeling analysis of cobalt-based Fischer-Tropsch catalyst particles

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Chinese Journal of Chemical Engineering 2024年第6期70卷 82-92页

作者： Huashuai Wu Gang wang yong Yang yongwang Li College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China National Energy Research&Development Center for Coal to Liquid Fuels Synfuels China CompanyLimitedBeijing 101400China

The influences of particle size,shape,and catalyst distribution on the reactivity and hydrocarbon product selectivity of a cobalt-based catalyst for Fischer-Tropsch synthesis were investigated in the present work.A self-consistent kinetic model for Fischer-Tropsch reaction proposed here was found to correlate experimental data well and hence was used to describe the consumption rates of reactants and formation rates of hydrocarbon *** perturbed-chain statistical associating fluid theory equation of state was used to describe vapor-liquid equilibrium behavior associated with Fischer-Tropsch *** interaction between intraparticle diffusion and Fischer-Tropsch reaction was investigated in *** showed that in order to avoid the adverse influence of intraparticle diffusional limitations on catalyst reactivity and product selectivity,the use of small particles is *** eggshell spherical particles are shown to keep the original catalyst reactivity and enhance the selectivity of heavy hydrocarbon *** suitable layer thickness for a spherical particle with a diameter of 2 mm is nearly 0.15 *** the same outer diameter of 2 mm,the catalyst reactivity and heavy product selectivity of hollow cylindrical particles with a layer thickness of 0.25 mm are found to be larger than eggshell spherical *** the viewpoint of catalytic performance,hollow cylindrical particles are a better choice for industrial applications.

关键词： Fischer-Tropsch synthesis Kinetic modeling Vapor-liquid equilibria Numerical simulation Intraparticle diffusion Particle shapes

Fast Cross-Platform Binary Code Similarity Detection Framework Based on CFGs Taking Advantage of NLP and Inductive GNN

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Chinese Journal of Electronics 2024年第1期33卷 128-138页

作者： Jinxue PENG yong wang Jingfeng XUE Zhenyan LIU School of Computer Science and Technology Beijing Institute of Technology

Cross-platform binary code similarity detection aims at detecting whether two or more pieces of binary code are similar or not. Existing approaches that combine control flow graphs(CFGs)-based function representation and graph convolutional network(GCN)-based similarity analysis are the best-performing ones. Due to a large amount of convolutional computation and the loss of structural information, the use of convolution networks will inevitably bring problems such as high overhead and sometimes inaccuracy. To address these issues, we propose a fast cross-platform binary code similarity detection framework that takes advantage of natural language processing(NLP)and inductive graph neural network(GNN) for basic blocks embedding and function representation respectively by simulating extracting structural features and temporal features. GNN’s node-centric and small batch is a suitable training way for large CFGs, it can greatly reduce computational overhead. Various NLP basic block embedding models and GNNs are evaluated. Experimental results show that the scheme with long short term memory(LSTM)for basic blocks embedding and inductive learning-based Graph SAGE(GAE) for function representation outperforms the state-of-the-art works. In our framework, we can take only 45% overhead. Improve efficiency significantly with a small performance trade-off.

关键词： Training Semantics Process control Binary codes Feature extraction Natural language processing Graph neural networks

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Experimental and Numerical Investigation of Non-synchronous Blade Vibration Excitation in a Transonic Axial Compressor

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Journal of Thermal Science 2024年第2期33卷 602-610页

作者： wang Songbai WU Yadong CHEN yong CAO zhipeng School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China AECC Sichuan Gas Turbine Establishment Chengdu610500China

The complex flow phenomenon of rotating instability(RI) and its induced non-synchronous vibration(NSV) have become a significant challenge as they continuously increase aerodynamic *** study aims to provide an understanding of the non-synchronous blade vibration phenomenon caused by the rotating instability of a transonic axial compressor *** this case,blade vibrations and non-synchronous excitation are captured by strain gauges and unsteady wall pressure transducer *** numerical simulations for a full-annulus configuration are used to obtain the non-synchronous flow *** results show that the first-stage rotor blade exhibits an NSV close to the first bending mode;NSV is accompanied by a sharp increase in pressure pulsation;amplitude can reach 20%,and unsteady aerodynamic frequency will lock in a structural mode frequency when the blade vibrates in a large-amplitude *** predicted NSV frequency aligns well with the experimental *** dominant mode of circumferential instability flow structure is approximately 47% of the number blades,and the cell size occupies 2-3 pitches in the circumferential *** full-annulus unsteady simulations demonstrate that the streamwise oscillation of the shedding and reattachment vortex structure is the main cause of NSV owing to the strong interaction between the tip leakage and separation vortices near the suction surface.

关键词： non-synchronous vibration transonic axial compressor rotor blade rotating instabilities unsteady flow

A photogrammetric approach for quantifying the evolution of rock joint void geometry under varying contact states

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International Journal of Mining Science and Technology 2024年第4期34卷 461-477页

作者： Rui yong Changshuo wang Nick Barton Shigui Du Institute of Rock Mechanics Ningbo UniversityNingbo 315211China Nick Barton&Associates Fjordveien 65cHøvik 1363Norway

Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage ***,existing techniques often require specialized equipment and skilled operators,posing practical *** this study,a cost-effective photogrammetric approach is ***,local coordinate systems are established to facilitate the alignment and precise quantification of the relative position between two halves of a rock ***/pull tests are conducted on rock joints with varying roughness levels to induce different contact states.A high-precision laser scanner serves as a benchmark for evaluating the photogrammetry *** certain deviations exist,the measured evolution of void geometry is generally consistent with the qualitative findings of previous *** photogrammetric measurements yield comparable accuracy to laser scanning,with maximum errors of 13.2%for aperture and 14.4%for void *** joint matching coefficient(JMC)measurement errors are below 20%.Larger measurement errors occur primarily in highly mismatched rock joints with JMC values below 0.2,but even in cases where measurement errors exceed 80%,the maximum JMC error is only ***,the proposed photogrammetric approach holds promise for widespread application in void geometry measurements in rock joints.

关键词： Rock joint Void geometry evolution Photogrammetry Aperture Void volume Joint matching coefficient

Rhodium-catalyzed Doyle-Kirmse rearrangement reactions of sulfoxoniun ylides

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Chinese Chemical Letters 2024年第4期35卷 363-366页

作者： Ying-Di Hao zhi-Qian Lin Xiao-Yu Guo Jiao Liang Can-Kun Luo Qian-Tao wang Li Guo yong Wu Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Department of Medicinal Chemistry Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial TechnologyWest China School of PharmacySichuan UniversityChengdu 610041China

Doyle-Kirmse rearrangement reactions have received continuous attention as an important method for constructing complex chemical structures. Herein, we disclosed an efficient rhodium-catalyzed DoyleKirmse rearrangement reaction, which can simultaneously construct C–C bonds and C–X(X = S/Se) bonds using sulfoxonium ylides as starting materials to obtain sulfur-or selenium-containing compounds. This strategy is characterized by the safer and greener carbene precursor, high yields and broad substrate scope, possessing a wide range of application.

关键词： Sulfoxonium ylides Rhodium(Ⅱ)-catalyzed Carbene Rearrangement reactions One-pot process

Target Controllability of Multi-Layer Networks With High-Dimensional Nodes

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IEEE/CAA Journal of Automatica Sinica 2024年第9期11卷 1999-2010页

作者： Lifu wang Zhaofei Li Ge Guo zhi Kong School of Control Engineering Northeastern University at QinhuangdaoQinhuangdao 066004China

This paper studies the target controllability of multilayer complex networked systems,in which the nodes are highdimensional linear time invariant(LTI)dynamical systems,and the network topology is directed and *** influence of inter-layer couplings on the target controllability of multi-layer networks is *** is found that even if there exists a layer which is not target controllable,the entire multi-layer network can still be target controllable due to the inter-layer *** the multi-layer networks with general structure,a necessary and sufficient condition for target controllability is given by establishing the relationship between uncontrollable subspace and output *** the derived condition,it can be found that the system may be target controllable even if it is not state *** this basis,two corollaries are derived,which clarify the relationship between target controllability,state controllability and output *** the multi-layer networks where the inter-layer couplings are directed chains and directed stars,sufficient conditions for target controllability of networked systems are given,*** conditions are easier to verify than the classic criterion.

关键词： High-dimensional nodes inter-layer couplings multi-layer networks target controllability

Insight into structural degradation of NCMs under extreme fast charging process

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Rare Metals 2024年第1期43卷 41-50页

作者： Yu Tang Xing-Yu wang Jin-Can Ren Bo-Wen Chen zhi-yong Huang Wei wang Ya-Lan Huang Bing-Hao Zhang Si Lan Zhang-Long He Qi Liu Hao He Department of Physics City University of Hong KongHong Kong 999077China Shenzhen Research Institute City University of Hong KongShenzhen 518057China College of Materials Science and Engineering Changsha University of Science&TechnologyChangsha 410114China

Lithium-ion batteries(LIBs)with extreme fast charging(XFC)capability are considered an effective way to alleviate range anxiety for electric vehicle(EV)*** to the high ionic and electronic conductivity of LiNi_(x)Co_(y)Mn_zO_(2)(x+y+z=1,NCM)cathodes,the inevitable Li plating of graphite in NCM|graphite cell is usually identified as a key bottleneck for XFC ***,the capacity decay mechanism of cathode materials under XFC has not been fully *** this work,three typical NCM cathode materials with different Ni fractions were chosen and their electrochemical performances under XFC associated with structural evolution were investigated.A faster capacity decay of NCMs under XFC conditions is observed,especially for Ni-rich ***-situ X-ray diffraction(XRD)reveals that the multiple caxis parameters appear at the high-voltage regions in Nirich NCMs,which is probably triggered by the larger obstruction of Li(de)***,NCMs with moderate Ni fraction also present a similar trend under XFC *** phenomenon is more detrimental to the structural and morphological stability,resulting in a faster capacity decay than that under low current *** work provides new insight into the degradation mechanism of NCMs under XFC conditions,which can promote the development of NCM cathode materials with XFC capability.

关键词： Lithium-ion batteries Ni fraction Extreme fast charging Structural evolution