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Numerical investigation of rock dynamic fragmentation during rockslides using a coupled 3D FEM-DEM method

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Journal of Mountain Science 2022年第4期19卷 1051-1069页

作者： LIU Yang WENG Lei chu Zhao-fei School of Civil Engineering Wuhan UniversityWuhan 430072China

Rockslides are one of the most common geological hazards in mountainous areas and can pose significant threats to the safety of human lives and infrastructures. Studying the dynamic fragmentation process, and fragment characteristics of rock blocks during rockslides is of great significance. In this study,the influences of the slope angle on the dynamic fragmentation process, damage and energy evolution,and the fragments’ flying velocity and flying angle were systematically investigated using a coupled 3D FEM-DEM method. An improved fragment search algorithm was first proposed to more effectively extract the information of the fragments after impacting. The input parameters in the numerical modeling were carefully calibrated based on the quasi-static uniaxial compression tests and the rockimpact tests. The complex fragmentation process of rock block sliding along an inclined slope was simulated. The results indicate that the fragmentation intensity gradually increases with increasing the slope angle, and the fragmentation intensity of the front region of the rock block is always higher than that of the rear region. Additionally, the slope angle can significantly affect the damage ratio, energy dissipation, and the ratio of tensile crack to shear crack during the rockslides. The number of the fragments having higher flying velocities and larger flying angles increases with increasing the slope angle,which contributes to a larger spreading distance and a wider deposition area.

关键词： Rockslides Dynamic fragmentation Fragment characteristics 3D FEM-DEM Numerical modelling

Clonal Plasticity in Response to Reciprocal Patchiness of Light and Nutrients in the Stoloniferous Herb Glechoma Iongituba L.

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Journal of Integrative Plant Biology 2006年第4期48卷 400-408页

作者： Yu chu fei-Hai Yu Ming Dong Laboratory of Quantitative Vegetation Ecology Institute of Botany the Chinese Academy of Sciences Beijing 100093 China

Interconnected ramets of clonal plants can functionally specialize in the uptake of resources from aboveground and/or underground sources. Ramet pairs of the clonal stoloniferous herb Glechoma Iongltuba L. were grown In spatially heterogeneous environments with complementary availability of light and nutrients. Plasticity with respect to root-shoot ratio, fitness-related traits （biomass, number of ramets and dry weight per ramet）, morphological traits （lamina area, root length） were experimentally examined. The aim was to understand the adaptation of G. Iongltuba to an environment with reciprocal patchiness of light and soil nutrients by plasticity In Its root-shoot ratio and clonal morphology. The results showed that the performance of ramets growing In patches with high light Intensity and low soil nutrients into the adjacent opposite patches was Increased in terms of fitness-related traits. However, the performance of those from patches with low light Intensity and high soil nutrients into the adjacent opposite patches was not changed. The root-shoot ratio and clonal morphology were plastic. Morphological traits such as lamina area and root length were altered In a way that enhanced the capture of light resources and soil nutrients. Apparent reciprocal resource transport between the ramets In an environment of reciprocal patchiness of resources can enhance the growth of ramets with complementary resource deficiencies.

关键词： clonal plant clonal plasticity complementary patchiness functional specialization light soil nutrients.

A model for parameter estimation of multistage centrifugal compressor and compressor performance analysis using genetic algorithm

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Science China(Technological Sciences) 2012年第11期55卷 3163-3175页

作者： chu fei WANG FuLi WANG XiaoGang ZHANG ShuNing College of in formation Science and Engineering Northeastern UniversityShenyang 110819China State Key Laboratory of Integrated Automation for Process Industries Northeastern UniversityShenyang 110819China

A model for performance prediction of multistage centrifugal compressor is proposed. The model allows the users to predict the compressor performance, e.g. pressure ratio, efficiency and losses using the compressor geometric information and speed by a stage stacking calculation based on the characteristics of each stage. To develop the compressor elemental stage charac- teristics, the compressor losses, such as incidence losses and friction losses, are mathematically modeled. For a composite sys- tems, for instance a gas turbine power plant, the performance of the multistage centrifugal compressor can be evaluated. Since some important parameters of the compressor model, e.g., the slip factor or, shock loss coefficient （and reference diameter DI, are hard to be determined by empirical laws, a genetic algorithm （GA） is used to solve the parameter estimation problem of the proposed model, and in turn the compressor performance analysis and parameters study are performed. The surge line for the multistage centrifugal compressor can also be determined from the simulation results. Furthermore, the model presented here provides a valuable tool for evaluating the multistage centrifugal compressor performance as a function of various operation parameters.

关键词： performance predication centrifugal compressor incidence loss genetic algorithm surge line

Improved fast model migration method for centrifugal compressor based on bayesian algorithm and Gaussian process model

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Science China(Technological Sciences) 2018年第12期61卷 1950-1958页

作者： chu fei DAI BangWu LU NanNan MA XiaoPing WANG FuLi School of Information and Control Engineering China University of Mining and Technology State Key Laboratory of Integrated Automation for Process Industries Northeastern University

Design and operation optimization of centrifugal compressor are always based on an accurate prediction model, however, due to the short time operation and lack of data information, it is difficult to get an accurate prediction model of a new centrifugal compressor in time. This paper applies an improved fast model migration method(FMM method) to develop the model of the new centrifugal compressor. The method adapts a Gaussian Process(GP) model from an old centrifugal compressor to fit a new and similar centrifugal compressor, and the adaptation is conducted by a scale-bias adjustment migration technology. In order to obtain the better estimated parameters of migration, Bayesian method, which takes the prior knowledge into consideration, is used in the sequential experiment. The approach is validated by a specific simulation bench. The results indicate that the applied approach can achieve a better prediction precision with fewer data of the new centrifugal compressor compared to pure GP method, and can model the new centrifugal compressor rapidly.

关键词： Bayesian centrifugal compressor Gaussian process model model migration performance prediction

Online complex nonlinear industrial process operating optimality assessment using modified robust total kernel partial M-regression

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Chinese Journal of Chemical Engineering 2018年第4期26卷 775-785页

作者： fei chu Wei Dai Jian Shen Xiaoping Ma Fuli Wang School of Information and Control Engineering China University of Mining and Technology Xuzhou 221116 China State Key Laboratory of Integrated Automation for Process Industries Northeastern University Shenyang 110819 China College of Information Science and Engineering Northeastern University Shenyang 110819 China

Although industrial processes often perform perfectly under design conditions, they may deviate from the optimal operating point owing to parameters drift, environmental disturbances, etc. Thus, it is necessary to develop efficacious strategies or procedure to assess the process performance online. In this paper, we explore the issue of operating optimality assessment for complex industrial processes based on performance-similarity considering nonlinearities and outliers simultaneously, and a general enforced online performance assessment framework is proposed. In the offline part, a new and modified total robust kernel projection to latent structures algorithm,T-KPRM, is proposed and used to evaluate the complex nonlinear industrial process, which can effectively extract the optimal-index-related process variation information from process data and establish assessment models for each performance grades overcoming the effects of outlier. In the online part, the online assessment results can be obtained by calculating the similarity between the online data from a sliding window and each of the performance grades. Furthermore, in order to improve the accuracy of online assessment, we propose an online assessment strategy taking account of the effects of noise and process uncertainties. The Euclidean distance between the sliding data window and the optimal evaluation level is employed to measure the contribution rates of variables, which indicate the possible reason for the non-optimal operating performance. The proposed framework is tested on a real industrial case: dense medium coal preparation process, and the results shows the efficiency of the proposed method comparing to the existing method.

关键词： Performance assessment Optimization Model Economics T-KPRM Robust

Defect-Tolerant Mapping of CMOL Circuit Targeting Delay Optimization

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Journal of Computer Science & Technology 2021年第5期36卷 1118-1132页

作者： Xiao-Jing Zha Yin-Shui Xia Shang-Luan Xie Zhu-fei chu Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China

In view of the significant number of defective nanodevices in the Cmos/nanowire/MOLecular hybrid(CMOL)circuit,defect-tolerant mapping is an essential step to achieve correct logic operations in defective CMOL ***,less effort has been made to improve circuit delay by defect-tolerant *** this paper,the factors affecting the delay of mapped circuits are analyzed,and the path-tree based defect-tolerant mapping method for the delay optimization is *** the logic-domain,the terminology of the path tree is presented,and the logic circuit is first partitioned into multiple path ***,the mapping areas in the physic-domain are pre-planned for(near)critical path *** the mapping process,the specific mapping modes and an updating strategy are formulated to map the path trees:inputs are mapped based on input sorting;(near)critical path trees are mapped with priority,while the others are mapped in a hierarchical ***,an improved tabu search algorithm is employed to verify the validity of the proposed defect-tolerant mapping *** evaluations on the ISCAS benchmarks show that the proposed method can reduce circuit delay by 15.22%.

关键词： nanohybrid circuit defect-tolerant mapping delay optimization

Universal cooling patterns of the butterfly wing scales hierarchy deduced from the heterogeneous thermal and structural properties of Tirumala limniace(Lepidoptera:Nymphalidae,Danainae)

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Insect Science 2022年第6期29卷 1761-1772页

作者： chu-fei Tang Fan-Fan Li Ye Cao Huai-Jian Liao Institute of Leisure Agriculture Jiangsu Academy of Agricultural SciencesNanjingChina Key Laboratory of Urban Agriculture Ministry of Agriculture and Rural AffairsShanghaiChina

The radiative cooling of butterfly wing scales hierarchy has great value in understanding how poikilotherms adapt to the environment and developing bionic ***,it remains unclear what the cooling system is like and how the vari-ation of hierarchy affects the cooling ***,the correlation between the variations of the structure and emissivity of scale hierarchy is thoroughly investigated in Tirumala limniace(Cramer,1775),whose thermal properties are highly heteroge-neous among different wings and regions but similar between males and ***-terns were deduced from the biological and model simulation *** scale hierarchy varies at the micro-to nanolevel on both surface and section,correspond-ing to the variating *** on wing veins and margins have large nanostruc-tured units with small lumens and are distinctly thickened,which bring extraordinarily high *** variations of light and dark scales,respectively,lead to the high emissivity of the middle region of wings and the front ***,the elevation of the inner surface area and the thickness of the chitin is the key to enhancing the cooling *** the first time,the effects of the variation of hierarchy toward emissivity of the mid-infrared spectrum are systematically *** is demonstrated that wing scales integrally differentiate in coping with the heterogeneous cooling needs,which may benefit in balancing multifunctions and the development toward the adap-tation to the abiotic *** study provides insights into the comprehensive thermoregulation system of butterflies and the further development of radiative cooling materials.

关键词： butterfly emissivity heterogeneous hierarchy radiative cooling wing scales

Cell Mapping for Nanohybrid Circuit Architecture Using Genetic Algorithm

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Journal of Computer Science & Technology 2012年第1期27卷 113-120页

作者： Zhu-fei chu Yin-Shui Xia Lun-Yao Wang School of Information Science and Engineering Ningbo UniversityNingbo 315211China

Nanoelectronics constructed by nanoscale devices seems promising for the advanced development of integrated circuits （ICs）. However, the lack of computer aided design （CAD） tools seriously hinders its development and applications. To investigate the cell mapping task in CAD flow, we present a genetic algorithm （GA） based method for Cmos/nanowire/MOLecular hybrid （CMOL）, which is a nanohybrid circuit architecture. By designing several crossover operators and analyzing their performance, an efficient crossover operator is proposed. Combining a mutation operator, a GA based algorithm is presented and tested on the International Symposium on Circuits and Systems （ISCAS） benchmarks. The results show that the proposed method not only can obtain better area utilization and smaller delay, but also can handle larger benchmarks with CPU time improvement compared with the published methods.

关键词： nanohybrid circuit cell mapping genetic algorithm optimization

A Semi-Tensor Product Based All Solutions Boolean Satisfiability Solver

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Journal of Computer Science & Technology 2023年第3期38卷 702-713页

作者：潘鸿洋储飞 Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China

Boolean satisfiability (SAT) is widely used as a solver engine in electronic design automation (EDA). Typically, SAT is used to determine whether one or more groups of variables can be combined to form a true formula. All solutions SAT (AllSAT) is a variant of the SAT problem. In the fields of formal verification and pattern generation, AllSAT is particularly useful because it efficiently enumerates all possible solutions. In this paper, a semi-tensor product (STP) based AllSAT solver is proposed. The solver can solve instances described in both the conjunctive normal form (CNF) and circuit form. The implementation of our method differs from incremental enumeration because we do not add blocking conditions for existing solutions, but rather compute the matrices to obtain all the solutions in one pass. Additionally, the logical matrices support a variety of logic operations. Results from experiments with MCNC benchmarks using CNF-based and circuit-based forms show that our method can accelerate CPU time by 8.1x (238x maximum) and 19.9x (72x maximum), respectively.

关键词： all solutions Boolean satisfiability(AllSAT) semi-tensor product of matrices conjunctive normal form(CNF)satisfiability circuit satisfiability