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Failure treatment strategy and fault-tolerant path planning of a space manipulator with free-swinging joint failure

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Chinese Journal of Aeronautics 2018年第12期31卷 2290-2305页

作者： Gang CHEN wen guo Qingxuan JIA Xuan WANG Yingzhuo FU School of Automation Beijing University of Posts and Telecommunications

Aiming at a space manipulator with free-swinging joint failure, a failure treatment strategy and fault-tolerant path planning method is proposed in this paper. This method can realize failure treatment of a space manipulator with free-swinging joint failure through determination of the optimal locked joint angle and dynamics model reconfiguration. Fault-tolerant path planning is realized by the establishment of the degraded workspace with integrated kinematics performance(DWWIKP) and an improved A-Star(A*) algorithm. This paper has the following *** determination of the optimal locked joint angle can ensure that the manipulator is able to continue follow-up tasks while maximizing the workspace of the manipulator after locking the fault joint. Underactuated control of a high degree-of-freedom(DOF) manipulator can be effectively solved through dynamics model reconfiguration. The analysis process of the dynamics coupling relationship can be applied to cases where the active joint and the passive joint are parallel or perpendicular to each other. The establishment of the DWWIKP can demonstrate the kinematics performance of the manipulator in both joint space and operation space comprehensively. The improved A*algorithm based on the integrated kinematics performance index(IKPI) can search a fault-tolerant task trajectory that satisfies the requirements of reachability and the overall kinematics performance simultaneously. The method proposed in this paper is verified by a 7-DOF manipulator, and it is available to any DOF manipulator with free-swinging joint failure.

关键词： Failure treatment Fault-tolerant Free-swinging Space manipulator Underactuated

Topological Lifshitz transition and novel edge states induced by non-Abelian SU(2)gauge field on bilayer honeycomb lattice

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Chinese Physics B 2022年第5期31卷 615-622页

作者： wen-Xiang guo Wu-Ming Liu Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

We investigate the SU(2)gauge effects on bilayer honeycomb lattice *** discover a topological Lifshitz transition induced by the non-Abelian gauge *** Lifshitz transitions are determined by topologies of Fermi surfaces in the momentum *** surface consists of N=8 Dirac points atπ-flux point instead of N=4 in the trivial Abelian regimes.A local winding number is defined to classify the universality class of the gapless *** also obtain the phase diagram of gauge fluxes by solving the secular ***,the novel edge states of biased bilayer nanoribbon with gauge fluxes are also investigated.

关键词： topological Lifshitz transition SU(2)gauge field bilayer honeycomb lattice

Martingale method for optimal investment and proportional reinsurance

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Applied Mathematics(A Journal of Chinese Universities) 2021年第1期36卷 16-30页

作者： LIU Shuang-sui guo wen-jing TONG Xin-le School of Finance Nanjing University of Finance and EconomicsNanjing 210023China.

Numerous researchers have applied the martingale approach for models driven by L¶evy processes to study optimal investment *** paper considers an insurer who wants to maximize the expected utility of terminal wealth by selecting optimal investment and proportional reinsurance *** insurer's risk process is modeled by a L¶evy process and the capital can be invested in a security market described by the standard Black-Scholes *** the martingale approach,the closed-form solutions to the problems of expected utility maximization are *** examples are presented to show the impact of model parameters on the optimal strategies.

关键词： martingale method proportional reinsurance investment exponential utility quadratic utility.

Model-constrained and data-driven double-supervision acoustic impedance inversion

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Petroleum Science 2023年第5期20卷 2809-2821页

作者： Dong-Feng Zhao Na-Xia Yang Jin-Liang Xiong guo-Fa Li Shu-wen guo State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China Dagang Oil Field PetroChinaTianjin300280China Research Institute of Exploration and Development Dagang Oil FieldPetroChinaTianjin300280China

Seismic impedance inversion is an important technique for structure identification and reservoir ***-based and data-driven impedance inversion are the commonly used inversion *** practice,the geophysical inversion problem is essentially an ill-posedness problem,which means that there are many solutions corresponding to the same seismic ***,regularization schemes,which can provide stable and unique inversion results to some extent,have been introduced into the objective function as constrain *** them,given a low-frequency initial impedance model is the most commonly used regularization method,which can provide a smooth and stable ***,this model-based inversion method relies heavily on the initial model and the inversion result is band limited to the effective frequency bandwidth of seismic data,which cannot effectively improve the seismic vertical resolution and is difficult to be applied to complex structural ***,we propose a data-driven approach for high-resolution impedance inversion based on the bidirectional long short-term memory recurrent neural network,which regards seismic data as time-series rather than image-like *** with the model-based inversion method,the data-driven approach provides higher resolution inversion results,which demonstrates the effectiveness of the data-driven method for recovering the high-frequency ***,judging from the inversion results for characterization the spatial distribution of thin-layer sands,the accuracy of high-frequency components is difficult to ***,we add the model constraint to the objective function to overcome the shortages of relying only on the data-driven ***,constructing the supervisor1 based on the bidirectional long short-term memory recurrent neural network,which provides the predicted impedance with higher ***,convolution constraint as supervisor2 is introduced into the objective fu

关键词： Acoustic impedance inversion Model constraints Double supervision BiLSTM neural network Reservoir structure characterization

Microstructure evolution of coke under CO2 and H2O atmospheres

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Journal of Iron and Steel Research International 2020年第7期27卷 743-754页

作者： Jun Zhao Hai-bin Zuo Chao Ling wen-tao guo Jing-song Wang Qing-guo Xue State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The microstructure of coke has an important influence on its thermal *** solution loss reactions of coke in CO2 and H2O atmospheres were investigated by in situ *** results showed that the isotropic components had a more vigorous reaction than the anisotropic components,and the solution loss reaction of the fine-grained mosaic structure was faster than that of the coarse-grained mosaic structure under the CO2 and H2O *** coarse-grained mosaic structure and the flowing structure had a relatively higher anti-erosion ability in the CO2 atmosphere than in the H2O atmosphere,and there was no distinct difference in the solution loss of the isotropic structure under the CO2 and H2O *** electron probe microanalysis showed that the Al-Si-Fe compounds in the carbon matrix had positive influence on the solution loss reaction of the anisotropic *** iron compounds were able to destroy the pore walls of coke and accelerate the solution loss rate of coke.

关键词： Coke Microstructure Solution loss reaction In situ observation Atmosphere

Distribution, failure risk and reinforcement necessity of check-dams on the Loess Plateau: a review

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Journal of Mountain Science 2021年第2期18卷 499-509页

作者： guo wen-zhao WANG wen-Long XU Qiang HU Jian-jun ZHU Li-li State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Water and Soil ConservationNorthwest A&F UniversityYangling 712100China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of SciencesChengdu 610059China Xi'an Planning Design&Research InstituteUpper and middle Yellow River BureauYellow River Conservancy CommissionMinistry of Water ResourcesXi'an 710021China

Check-dams are the most important measure to control the soil and water loss in highly erodible catchments on the Chinese Loess *** on the data of check-dams from 1950 to 2014,our study roundly analyzed the regional distribution,function and the problems of check-dams on the Loess Plateau.A total of 17,094 check-dams with a storage capacity of over 100,000 m^(3) and an average density of 0.027 counts km^(-2) were installed on the Loess ***-dams’densities varied greatly in the Qinghai Province,Gansu Province,Ningxia Hui Autonomous Region,Inner Mongolia Autonomous Region,Shaanxi Province,Shanxi Province and Henan *** highest density of check-dams reached 0.088 counts km^(-2) in Shaanxi Province,whereas the lowest density of check-dams was only 0.005 counts km^(-2) in Qinghai ***,after decades of operation,3025 large check-dams and 2257 medium check dams are dangerous and have security risks,which are seriously threatening downstream *** dangerous rate of checkdams is ***,the check-dams in Shanxi and Qinghai Province have the highest dangerous rates,with both exceeding 53%.Therefore,there is an urgent need for carrying out reinforcement of the dangerous *** results are helpful to policymakers to extend and develop check-dams.

关键词： Check-dam Soil erosion Sediment Gully Dam failure Chinese Loess Plateau

Study on the Interaction of Pd-TMPyP with ctDNA by Solid-substrate Room Temperature Phosphorescence

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Chinese Chemical Letters 2006年第2期17卷 253-254页

作者： Li Min guo wen Juan DONG Chuan DONG School of Chemistry and Chemical Engineering Shanxi University Taiyuan 030006

The interaction between calf thymus DNA （ctDNA） and Pd （Ⅱ） meso-tetralds- （4-N-methyl pyridiniumyl） porphyrin （Pd-TMPyP） was investigated by steady solid-substrate room temperature phosphorescence （SS-RTP）. The SS-RTP intensity and lifetime of Pd-TMPyP enhanced with the increasing ctDNA. The anion quenching experiment of Pd-TMPyP indicated that Pd-TMPyP intercalated into ctDNA, which was also approved by UV-Vis spectra. Keywords： Pd-TMPyP, ctDNA, SS-RTP, intercalation

关键词： Pd-TMPyP ctDNA SS-RTP intercalation.

Theoretical Studies on Structures and Electron Affinities of 5-and 6-Halouracils

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Chemical Research in Chinese Universities 2009年第3期25卷 388-396页

作者： WANG Hui-ping XU wen-guo ZHANG Hong-xing State Key Laboratory of Theoretical Chemistry Institute of Theoretical Chemistry Jilin University Changchun 130021 P R. China Institute for Chemical Physics Beijing Institute of Technology Beijing 100081 P. R. China

The molecular structures and electron affinities of 5- and 6-halouracils（XU, X=F, Cl, Br） were determined by means of five different density functional methods. The basis set used in this work is of double-（plus polariza- tion（DZP） quality with additional diffuse s- and p-type functions, denoted DZP＋＋. The geometries were fully optimized with each density functional theory（DFT） method, and discussed. Three different types of the neutral-anion energy separations reported in this work are the adiabatic electron affinity（AEA）, the vertical electron affinity（VEA）, and the vertical detachment energy（VDE）. An excellent agreement between our B3LYP results and those obtained by other calculations regarding the structural modifications and electron affinities of neutral and anion 5XU was found. The differences in charge distribution between uracil and halogenated uracils were indicated, thus the ability to form the hydrogen bonds of halogenated uracils was discussed. It shows the applicability of the DFT/DZP＋＋ method to predict the similar molecular models at a highly economical computational cost.

关键词： Electron affinity Vertical electron affinity Vertical detachment energy Halouracil Charge distribution

Mathematical model for flood routing based on cellular automaton

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Water Science and Engineering 2014年第2期7卷 133-142页

作者： Xin CAI Yi LI Xing-wen guo Wei WU State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University College of Mechanics and Materials Hohai University College of Water Conservancy and Hydropower Engineering Hohai University Nanjing Municipal Bureau of Water Resources

Increasing frequency and severity of flooding have caused tremendous damage in China, requiring more essential countermeasures to alleviate the damage. In this study, the dynamic simulation property of a cellular automaton was used to make further progress in flood routing. In consideration of terrain＇s influence on flood routing, we regarded the terrain elevation as an auxiliary attribute of a two-dimensional cellular automaton in path selection for flood routing and developed a mathematical model based on a cellular automaton. A numerical case of propagation of an outburst flood in an area of the lower Yangtze River was analyzed with both the fixed-step and variable-step models. The results show that the flood does not spread simultaneously in all directions, but flows into the lower place first, and that the submerged area grows quickly at the beginning, but slowly later on. The final submerged areas obtained from the two different models are consistent, and the flood volume balance test shows that the flood volume meets the requirement of the total volume balance. The analysis of the case shows that the proposed model can be a valuable tool for flood routing.

关键词： cellular automaton flood routing mathematical model