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Spatiotemporal evolution of Ediacaran-Cambrian(ca. 551–523 Ma)sponges in South China and their simulated contributions to marine oxygenation

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Science China Earth Sciences 2025年

作者： yan ye Lei ZHANG Can CHEN Shan CHANG Yuhao YI Qinglai FENG State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(Wuhan) School of Earth Science China University of Geosciences(Wuhan) Department of Geology Lund University Institute of Sedimentary Geology Chengdu University of Technology Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of Technology Second Geological Brigade of Hubei Geological Bureau College of Urban and Environmental Sciences Hubei Normal University Exploration and Development Research Institute SINOPEC Jianghan Oilfield Company

The origin and evolution of sponges have attracted interest, not only because they are among the most basal metazoans, but also because they act as important ecological engineers in the ocean. Previous research suggested that sponge groups diversified quickly during the Cambrian Series 2, while Terreneuvian sponge fossils are conspicuously rare and poorly substantiated. yet, an increasing number of sponge spicules have been reported from the Ediacaran-Cambrian(E-C, ca.551–523 Ma) transitional carbonates/cherts worldwide, particularly in South China, which calls for updated discussions. Ocean oxygenation has been widely proposed to play a critical role in organismal evolution, but its relationship with sponges is unclear and falls into a “chicken-egg” dilemma. In this study, we summarize reported sponge spicule distributions from five E-C sections in South China to investigate the early evolutionary pattern of siliceous sponges. According to current stratigraphic correlation,monaxons first appear in the late Ediacaran in the intrashelf basin-slope area, and then potentially expand to the continental shelf and deep basin in the lower Cambrian. In these sections, the abundance, size, and diversity of monaxons increase upwards,followed by the appearance of diaxons, triaxons and then polyactines. Despite the uncertain affinity of the sponge fossils, it is possible that siliceous hexactinellids evolved later than siliceous demosponges, given that the earliest spicule assemblages are exclusively composed of monaxons, which commonly form bundles comparable to modern demosponges. New geochemical data from the Sifangjing section, Guizhou Province and the yanziqiao section, Hunan Province, South China show that the appearance of sponges usually corresponds to anoxic environment. In addition, we applied the recently proposed Biological Pump, Oxygen and Phosphorus(BPOP) model to trace the evolution of oceanic oxygen concentrations with the radiation of sponges. The results indic

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Backstepping sliding mode control for uncertain strict-feedback nonlinear systems using neural-network-based adaptive gain scheduling

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Journal of Systems Engineering and Electronics 2018年第3期29卷 580-586页

作者： yanG Yueneng yan ye College of Aerospace Science and Engineering National University of Defense Technology

A neural-network-based adaptive gain scheduling backstepping sliding mode control（NNAGS-BSMC） approach for a class of uncertain strict-feedback nonlinear system is ***, the control problem of uncertain strict-feedback nonlinear systems is formulated. Second, the detailed design of NNAGSBSMC is described. The sliding mode control（SMC） law is designed to track a referenced output via backstepping *** decrease chattering result from SMC, a radial basis function neural network（RBFNN） is employed to construct the NNAGSBSMC to facilitate adaptive gain scheduling, in which the gains are scheduled adaptively via neural network（NN）, with sliding surface and its differential as NN inputs and the gains as NN outputs. Finally, the verification example is given to show the effectiveness and robustness of the proposed approach. Contrasting simulation results indicate that the NNAGS-BSMC decreases the chattering effectively and has better control performance against the BSMC.

关键词： backstepping control sliding mode control(SMC) neural network(NN) strict-feedback system chattering decrease

Decoupled nonsingular terminal sliding mode control for affine nonlinear systems

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Journal of Systems Engineering and Electronics 2016年第1期27卷 192-200页

作者： Yueneng yang ye yan College of Aerospace Science and Engineering National University of Defense Technology

A decoupled nonsingular terminal sliding mode control（DNTSMC） approach is proposed to address the tracking control problem of affine nonlinear systems.A nonsingular terminal sliding mode control（NTSMC） method is presented,in which the nonsingular terminal sliding surface is defined as a special nonsingular terminal function and the convergence time of the system states can be *** affine nonlinear system is firstly decoupled into linear subsystems via feedback ***,a nonsingular terminal sliding surface is defined and the NTSMC method is applied to each subsystem separately to ensure the finite time convergence of the closed-loop *** verification example is given to demonstrate the effectiveness and robustness of the proposed *** proposed approach exhibits a considerable advantage in terms of faster tracking error convergence and less chattering compared with the conventional sliding mode control（CSMC）.

关键词： nonlinear control feedback linearization terminal sliding mode control nonsingular affine nonlinear system.

Theoretical Study on Photoisomerization of 2-Methylfuran to 3-Methylfuran

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Chinese Journal of Structural Chemistry 2006年第6期25卷 681-688页

作者： WANG yan-Xia ye Song Department of Chemistry Yunnan University Kunming 650091 China

In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF （CASSCF） molecular orbital method. Geometries of minima and transition states on the excited and ground states are fully optimized at the CAS level with a 6-3 IG＊ basis set. A multireference MP2 algorithm that has been implemented in Gaussian is used to correct the energetics for dynamic correlation. The topology and reaction funnels of the singlet, triplet （S0, T1, T2） and potential energy surfaces have been characterized along the reaction coordinates corresponding to the mechanism. The reaction proceeds via two diradical intermediates, one intermediate product and four transition states. The two diradical S 1/T2 and T1/S0 energy surface crossing points are located along the reaction path and a T1/T2 conical intersection is also located. From this point the reaction soon returns to T1 surface. It is the most reasonable that the intersystem crossing from T1 to S0 takes place.

关键词： CASSCF photoisomerization intersystem crossing point reaction path

Theoretical Study on the Triplet-sensitized Photolysis of 2,5-Dimethylfuran

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1145-1151页

作者： WANG yan-Xia ye Song Department of Chemistry Yunnan University Kunming 650091 China

In the present work, the triplet-sensitized photolysis of 2,5-dimethylfuran has been investigated with the complete active space SCF （CASSCF） molecular orbital method. Two different reaction routes through diradical and carbene intermediates respectively have been systematically studied, and the reaction via carbene intermediate is the major part well compatible with experiment. Geometries of minima and transition states on S0T1 surface were fully optimized at the CAS level with a 6-31G^＊ basis set. A multireference MP2 algorithm that has been implemented in Gaussian was used to correct the energetics for dynamic correlation. Four intersystem crossing points have been located and discussed, and two of them are efficient. Our computation indicates that the reaction must occur on the triplet-excited state.

关键词： CASSCF photolysis intersystem crossing point reaction path

Theoretical Study of the Photochemical Reaction Mechanism of Bicyclo[4.1.0]heptane

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Chemical Research in Chinese Universities 2006年第4期22卷 520-523页

作者： WANG yan-xia ye Song Department of Chemistry Yunnan University Kunming 650091 P. R. China

The photochemical reaction of bicyclo[4.1.0]heptane was studied at the complete active space SCF（CASSCF） level with a 6-31G^＊ basis set. A muhireference MP2 algorithm that has been implemented in the Gaussian program was used to correct the energetics for the dynamic correlation. Starting from the Franck-Condon excitation of bicyclo [ 4.1.0 ] heptane, the reaction is via two bonds＇ breakage to give rise to 1,6-heptdiene. One internal conversion （IC） and two intersystem crossing points（ISC） were located and are discussed separately. The reaction proceeds to its own characteristic product on the ground state.

关键词： CASSCF Intersystem crossing Photochemical reaction mechanism Internal conversion Bicyclo-[ 4.1.0 ] heptane 1-6 Heptadiene

ON THE STABILITY OF PERIODIC SOLUTIONS OF PIECEWISE SMOOTH PERIODIC DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2024年第4期44卷 1524-1535页

作者： Maoan HAN yan ye School of Mathematical Sciences Zhejiang Normal UniversityJinhua 321000China

In this paper,we address the stability of periodic solutions of piecewise smooth periodic differential *** studying the Poincarémap,we give a sufficient condition to judge the stability of a periodic *** also present... 详细信息

关键词： periodic solution Poincarémap periodic equation stability

Nuclear clustering in light neutron-rich nuclei

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Nuclear Science and Techniques 2018年第12期29卷 112-127页

作者： yang Liu yan-Lin ye School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University

Clustering is a general phenomenon observed in light nuclei, especially in neutron-rich nuclei in which molecular configurations can be formed with various combinations of valence neutrons. Thus far, many theoretical models have been developed to describe nuclear clustering phenomena. These models are outlined in this review article, with an emphasis on their basic formulations and physical ingredients. In addition, various experimental tools, such as inelastic excitation and decay, transfer reactions, and resonant scattering reactions, have been applied to investigate the cluster structures inside the nucleus. Each tool possesses certain advantages and favorable applications, which are also described. In the case of neutron-rich nuclei, cluster structures may be configured as molecular states that form rotational bands with an extremely large moment of inertia and generate relatively large cluster decay width. The major experimental criteria for the identification of cluster formation are discussed herein.

关键词：轻原子核中子聚类转移反应簇结构物理成分应用程序试验性

Design and Realization of Mineral Feeding SCADA System

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Journal of China University of Mining and Technology 2006年第1期16卷 68-70,76页

作者： ye yan-fei College of Electrical Engineering Hohai University Nanjing Jiangsu 210098 China

The grinding process in concentration plants of the metallurgical industry is of great importantce.. A mineral feed- ing SCADA system in the grinding process was designed with the idea of integrating management and control functions. A detailed design and realization method of control and supervisory control levels in the system was introduced. At the control level, with an algorithm of a separate integrated PID, four mineral feeding machines are run in turn. The supervisory control level can generate process flow graphs, statistical report forms, historical trends and at the same time, it has the functions of alarm, system administration, user login, etc. After the mineral SCADA system has been started, the mineral feeding is very stable, the workstation completely supervises and controls the entire process of mineral feeding, and at the same time histori- cal data is shown and questions can be answered conveniently. The system runs well in the MeiShan Concentration Plant of the Shanghai Bao Shan Steel Group.

关键词： mineral feeding SCADA system control level management