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International Journal of Minerals,Metallurgy and Materials 2019年第10期26卷 1217-1230页

作者： Peng Li Fen-hua Ren Mei-feng Cai Qi-feng Guo Hao-fei Wang Kang Liu School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing 100083China Beijing key Laboratory of Urban Underground Space Engineering University of Science and Technology BeijingBeijing 100083China

The size of underground openings in rock masses in metal mines is critical to the performance of the openings. In this study, the mechanical and acoustic emission (AE) characteristics of brittle rock-like specimens containing a circular opening with different ratios of opening diameter to sample size λ (λ = 0.1, 0.13, 0.17, 0.2, and 0.23) were investigated under uniaxial compression with AE monitoring. The results indicate that the opening size strongly affected the peak strength and the elastic modulus. Crack initiation first started from the upper surface of the specimens, not from the periphery of the openings. Tensile and shear cracks coexisted on the roof and floor of the specimens, whereas tensile cracks were dominant on the two sides. The fracture mode of samples with openings was partially affected by the relative size of the pillars and openings. The AE response curves (in terms of counts, cumulative energy, cumulative counts, and b-value) show that brittle failure was mainly a progressive process. Moreover, the AE information corresponded well with microcrack evolution in the samples and thus can be used to predict sample failure.

关键词： rock mechanics circular opening opening size uniaxial compression acoustic emission

Branch Convolution Quantization for Object Detection

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Machine Intelligence Research 2024年第6期21卷 1192-1200页

作者： Miao Li feng Zhang Cuiting Zhang The National Engineering&Technology Research Center for Application Specific Integrated Circuit Design(NECFAD) Institute of AutomationChinese Academy of SciencesBeijing100080China

Quantization is one of the research topics on lightweight and edge-deployed convolutional neural networks(CNNs).Usu-ally,the activation and weight bit-widths between layers are inconsistent to ensure good performance of CNN,meaning that dedicated hardware has to be designed for specific *** this work,we explore a unified quantization method with extremely low-bit quantized weights for all *** use thermometer coding to convert the 8-bit RGB input images to the same bit-width as that of the activa-tions of middle *** the quantization of the results of the last layer,we propose a branch convolution quantization(BCQ)*** with the extremely low-bit quantization of the weights,the deployment of the network on circuits will be simpler than that of other works and consistent throughout all the layers including the first layer and the last *** tiny_yolo_v3 and yolo_v3 on VOC and COCO datasets as examples,the feasibility of thermometer coding on input images and branch convolution quantization on output results is ***,tiny_yolo_v3 is deployed on FPGA,which further demonstrates the high performance of the proposed algorithm on hardware.

关键词： Branch convolution quantization thermometer coding extremely low-bit quantization hardware deployment object detection

Approximate Controllability of Second-order Semilinear Evolution Systems with Finite Delay

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Acta Mathematicae Applicatae Sinica 2021年第3期37卷 573-589页

作者： Xiao-feng SU Xian-long FU School of Mathematical Sciences Fudan UniversityShanghai 200433China School of Mathematical Sciences Shanghai Key Laboratory of PMMPEast China Normal UniversityShanghai200241China

In this work,we study the approximate controllability for a class of semilinear second-order control systems with finite *** conditions for approximate controllability are established by constructing fundamental solutions and using the resolvent condition and techniques on cosine family of linear *** illustrate the applications of the obtained results,an example is provided in the end.

关键词： approximate controllability second-order evolution equation fundamental solution cosine operator

Experimental and numerical investigation on the mechanical responses and cracking mechanism of 3D confined single-flawed rocks under dynamic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第2期14卷 477-493页

作者： Wei You feng Dai Yi Liu State key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China

Accurately characterizing the mechanical responses and cracking mechanism of three-dimensional confined fractured rocks under coupled static-dynamic loading is of paramount importance for underground engineering *** a modified split Hopkinson pressure bar(SHPB)system,five groups of single-flawed specimens with the axial prestress ratio from 0 to 0.8 are tested at the strain rates in the range of 65-205 s-1under a fixed radial *** results indicate that both the dynamic strength and total strength show significant positive linear correlations with the strain rate,and the dynamic strength shows more strain rate sensitivity under higher axial *** dynamic strength and corresponding failure strain decrease with increasing axial prestress,while the total strength is barely affected by the axial *** dynamic elastic modulus initially increases before the axial prestress ratio reaches 0.6 and then *** failure pattern of tested specimens changes from single diagonal failure to an“X”shaped conjugated failure as axial prestress ***,the progressive cracking processes of confined single-flawed specimens under different axial prestresses are numerically visualized by the discrete element method(DEM).Based on the displacement trend lines on both sides of cracking surface,five crack types are identified and classified in our *** displacement field distributions of the DEM models reveal that the macroscopic single diagonal failure under lower axial prestress is mainly controlled by mixed tensile-shear cracks,while the“X”shaped conjugated failure under higher axial prestress is shear dominated.

关键词： Confined flawed rock Split hopkinson pressure bar(SHPB) Cracking mechanism Discrete element method(DEM)

The Existence of Solutions for the Problem in the Optical Lattice with Nonlocal Nonlinearity

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Acta Mathematicae Applicatae Sinica 2012年第4期28卷 681-690页

作者： Rui-feng ZHANG Ren-tao LIU Institute of Contemporary Mathematics Henan University College of Mathematics and Information Science Henan University

We address the impact of nonlocality in the physical features exhibited by solitons supported by kerr-type nonlinear media with an imprinted optical lattice. We discuss the solitons solution for a class of nonlinear SchrSdinger equations in the optical lattice with nonlocal nonlinearity. We also show via a uniform priori estimate that existence and uniqueness of the global solution for the initial problem.

关键词： SchrSdinger equation Cauchy problem contract mapping principle Calerkin method

Effects of Guiding Angle on Plastic Metal Flow and Defects in Extrusion of Aluminum Alloy

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Journal of Materials Science & Technology 2008年第2期24卷 256-260页

作者： Shijian YUAN feng LI Zhubin HE School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

To reduce defects, such as the shrinkage cavity and the surface cracks caused by non-homogeneous metal flow in extrusion process, an extrusion method was proposed by using a die with the guiding angle. Numerical simulation and experiment were conducted to investigate the metal flow in this extrusion process. It is shown that the stress state at the bottom of the die is changed. The tendency to generate the dead zone is decreased by employing the guiding angle at the die entrance. The shrinkage cavity is reduced because the non-homogeneous metal flow at the final stage of extrusion is improved. The axial stress is decreased greatly so that the surface cracks caused by additional stress are avoided.

关键词： Guiding angle Extrusion Metal flow Defects

CMIP 6 models simulation of the connection between North/South Pacific Meridional Mode and ENSO

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Journal of Oceanology and Limnology 2024年第2期42卷 439-453页

作者： Yunlong LU Junqiao feng Dunxin HU key Laboratory of Ocean Circulation and Waves Chinese Academy of SciencesQingdao 266071China Institute of Oceanology Chinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

The subtropical North and South Pacific Meridional Modes(NPMM and SPMM)are well known precursors of El Niño-Southern Oscillation(ENSO).However,relationship between them is not *** the early 1980,the relationship experienced an interdecadal *** in this connection can be attributed mainly to the phase change of the Pacific decadal oscillation(PDO).During the positive phase of PDO,a shallower thermocline in the central Pacific is responsible for the stronger trade wind charging(TWC)mechanism,which leads to a stronger equatorial subsurface temperature *** dynamic process strengthens the connection between NPMM and *** with the negative phase of PDO,a shallower thermocline over southeastern Pacific allows an enhanced wind-evaporation-SST(WES)feedback,strengthening the connection between SPMM and *** 35 Coupled Model Intercomparison Project Phase 6(CMIP6)models,we examined the NPMM/SPMM performance and its connection with ENSO in the historical *** great majority of CMIP6 models can reproduce the pattern of NPMM and SPMM well,but they reveal discrepant ENSO and NPMM/SPMM *** intermodal uncertainty for the connection of NPMM-ENSO is due to different TWC mechanism.A stronger TWC mechanism will enhance NPMM *** SPMM,few models can simulate a good relationship with *** intermodel spread in the relationship of SPMM and ENSO owing to SST bias in the southeastern Pacific,as WES feedback is stronger when the southeastern Pacific is warmer.

关键词： North and South Pacific Meridional Modes(NPMM and SPMM) El Niño-Southern Oscillation(ENSO) Pacific decadal oscillation(PDO) Coupled Model Intercomparison Project Phase 6(CMIP6)

Simultaneous catalytic removal of NOx and diesel PM over La_(0.9) K_(0.1) CoO_3 catalyst assisted by plasma

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Journal of Environmental Sciences 2005年第2期17卷 220-223页

作者： PEIMei-xiang LINHe SHANGGUANwen-feng HUANGZhen InstituteofInternalCombustionEngine ShanghaiJiaotongUniversityShanghai200030China

The simultaneous removal of NOx and particulate matter(PM) from diesel exhaust is investigated over a mixed metal oxide catalyst of La 0.9 K 0.1 CoO 3 loaded on γ-Al 2O 3 spherules with the assistant of plasma. It was found that NOx was reduced by PM in oxygen rich atmosphere, the CO 2 and N 2 were produced in the same temperature window without considering the N 2 formed by plasma decomposition. As a result, the temperature for the PM combustion decreases and the reduction efficiency of NOx to N 2 increases during the plasma process, which indicated that the activity of the catalyst can be improved by plasma. The NOx is decomposed by plasma at both low temperature and high temperature. Therefore, the whole efficiency of NOx conversion is enhanced.

关键词： simultaneous removal plasma assisted catalysis NOx PM diesel

Mechanical properties and energy evolution of jointed rock specimens containing an opening under uniaxial loading

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International Journal of Minerals,Metallurgy and Materials 2021年第12期28卷 1875-1886页

作者： Peng Li Mei-feng Cai Pei-tao Wang Qi-feng Guo Sheng-jun Miao Fen-hua Ren School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing 100083China Beijing key Laboratory of Urban Underground Space Engineering University of Science and Technology BeijingBeijing 100083China

To investigate the impact of an opening and joints with different inclination angles on the mechanical response behavior,the energy evolution characteristics,and distribution law of granite specimens,uniaxial loading tests were performed on the parallel jointed rock samples with an *** indicated an initial decreasing trend of the strength and deformation parameters,which later increases with increased inclination angle,reaching minimum values when the inclination angle is 45°.Evolution curves of the elastic strain energy and dissipated energy with strain of the samples showed step-like gradual mutation *** peak total energy,peak elastic strain energy,peak dissipated energy,and total input energy during the failure of the samples showed significant nonlinear characteristics with increasing inclination *** opening and joints as well as the change of the inclination angle had significant influences on the proportion of the elastic strain energy of the samples prior to the peak,resulting in the difference of the distribution law of input ***,the energy mechanism of the sample failure was *** showed that the energy release was the internal cause of the sudden destruction of the entire rock mass.

关键词： deformation energy rock

Identification and quantification of benzimidazole metabolites of thiophonate-methyl sprayed on celery cabbage using SiO_2@NiO solid-phase extraction in combination with HPLC-MS/MS

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Chinese Chemical Letters 2020年第2期31卷 482-486页

作者： Qiongwei Yu Shijie Liu feng Zheng Huaming Xiao Hongyan Guan Yuqi feng key Laboratory of Analytical Chemistry for Biologyand Medicine(Ministry of Education) Department of ChemistryWuhan UniversityWuhan 430072China Quality Management Department Wuhan Hiteck Biological Pharma Co.Ltd.Wuhan 430056China

Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture ***,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to *** this paper,nickel oxide nanoparticle-deposited silica(SiO_2@NiO) composite was used for the selective enrichment and purification of TPM's BZD metabolites in celery cabbage sprayed with ***,high-performance liquid chromatography coupled with precursor ion scan-mass spectrometry(HPLC-PIS-MS) and high-resolution MS/MS analysis(HR-MS/MS) was utilized for their qualitative and quantitative ***-one potential TPM's BZD metabolites were found and four of them were *** metabolite was discovered for the first ***,a robust and sensitive quantitative method was developed with good linearities(R^2> 0.9972) within a wide range of 10.00-1000 ng/*** detection limits of three known TPM's metabolites were within the range of 3.20-4.90 ng/*** standard deviations(RSDs) of intra-day and inter-day precisions were less than 18.3%,which showed perfect *** method was successfully applied to monitoring TPM's BZD metabolites in celery cabbage sprayed with TPM and the concentration versus time curves of TPM's metabolites in celery cabbage were *** method is expected to be used to monitor BZD residues in various fruits and vegetables.

关键词： Thiophonate-methyl Benzimidazole metabolites Precursor ion scan-mass spectrometry High-resolution MS/MS analysis Celery cabbage