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尾矿砂动力特性的动三轴试验研究

黄金 2024年第7期45卷 94-101页

作者：常礼安张吉宏彭湘林中国有色金属工业西安勘察设计研究院有限公司陕西省尾矿库防灾减灾工程技术研究中心

尾矿库是堆存选矿后尾矿的场所,尾矿砂主要为细砂、粉砂等无黏性土,往往处于饱和状态,因此在地震作用下易发生液化并造成尾矿坝的失稳破坏。以某尾矿库为研究对象,通过现场勘察取样,对4种类型尾矿砂即尾中砂、尾细砂、尾粉砂和尾粉质黏... 详细信息

尾矿库是堆存选矿后尾矿的场所,尾矿砂主要为细砂、粉砂等无黏性土,往往处于饱和状态,因此在地震作用下易发生液化并造成尾矿坝的失稳破坏。以某尾矿库为研究对象,通过现场勘察取样,对4种类型尾矿砂即尾中砂、尾细砂、尾粉砂和尾粉质黏土的特征进行了描述和物理参数测试。采用STX-200液压伺服式动三轴试验仪对尾矿砂试样动弹性模量、动剪切模量和阻尼比等动力学参数进行了试验测试。结果表明:试样的初始动弹性模量和初始动剪切模量均随动应变的增大先减小后趋于稳定,且受试样固结围压影响很大;随着动应变的增大,试样最大阻尼比呈明显的非线性增大,即先迅速增大后缓慢增大并趋于平稳,但其受围压的影响较小。试验结果可为尾矿库在地震作用下的动力液化分析提供数据支持。

关键词：尾矿砂液化动三轴试验滞回曲线动力学参数

Overview of Torque Ripple Minimization Methods for Permanent Magnet Synchronous Motors Based on Harmonic Injection

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Chinese Journal of Electrical Engineering 2024年第2期10卷 16-29页

作者： peng Yi Wenzhi Zheng xianglin Li College of Electrical Engineering Qingdao UniversityQingdao 266071China

Permanent magnet synchronous motors(PMSMs)are widely used because of their high power/torque density and high efficiency,particularly in applications with strict requirements for arrangement space or weight,such as in the electric vehicle(EV)and aerospace ***,the PMSM torque ripple problem has received increasing interest because PMSM drive requirements continuously *** applications with complex transmission and a wide speed range,torque ripple can easily cause system resonance,which deteriorates the driving *** research status and latest progress in the minimization of PMSM torque ripple based on harmonic injection are ***,the causes of PMSM torque ripple are ***,the research status of the PMSM analytical model is introduced,and multiple current harmonic control and optimization methods are described in ***,future development trends in this field are analyzed.

关键词： Permanent magnet synchronous motor torque ripple minimization harmonic injection

Weakened interlayer coupling in two-dimensional MoSe2 flakes with screw dislocations

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Nano Research 2019年第8期12卷 1900-1905页

作者： Xiangzhuo Wang Huixia Yang Rong Yang Qinsheng Wang Jingchuan Zheng Lu Qiao xianglin peng Yongkai Li Dongyun Chen Xiaolu Xiong Junxi Duan Guangyu Zhang Jie Ma Junfeng Han Wende Xiao Yugui Yao Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systemsand School of PhysicsBeijing Institute of TechnologyBeijing 100081China Micronano Center Beijing Institute of TechnologyBeijing 100081China Institute of Physics Chinese Academy of SciencesBeijing 100190China

The screw dislocations are intriguing defects that are often observed in natural and artificial materials. The dislocation spirals break the reflection and inversion symmetries of the lattices and modify the interlayer coupling in layer-structured materials, inducing additional complexity in layer stacking and thus novel properties in materials. Here, we report on the interlayer coupling of two-dimensional (2D) MoSe2 flakes with screw dislocations by atomic force microscopy (AFM), Raman spectra and photoluminescence (PL) spectra. By controlling the supersaturation conditions, 2D MoSe2 flakes with screw dislocations are grown on amorphous SiO2 substrates by chemical vapor deposition (CVD). AFM measurements reveal that the interlayer spacing in such 2D MoSe2 flakes with screw dislocation is slightly widened with respect to the normal AA- or AB-stacked ones due to the presence of the screw dislocations. Raman and PL spectra show that the interlayer coupling is weaker and thus the band gap is wider than that in the normal AA- or AB-stacked ones. Our work demonstrates that the interlayer coupling of 2D transition metal dichalcogenides (TMDCs) flakes can be tuned by the induction of screw dislocations, which is very helpful for developing novel catalysts and electronic devices.

关键词： transition-metal dichalcogenides molybdenum selenide screw dislocations interlayer coupling band gap

黄土地区土壤中磷的含量分布、形态转化与磷肥合理施用

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土壤学报 1989年第4期26卷 344-352页

作者：彭琳彭祥林中国科学院西北水土保持研究所

黄土地区土壤中全磷与有效磷含量均有由北向南逐渐趋增的趋势,一般是:灌淤土较高,(土娄)土、褐土与黑垆土次之,黄绵土、灰钙土和黑钙土又次之,风沙土较低。土壤有效磷可分为4级,5.5ppm可作为土壤缺磷临界值,5.5—10.5 ppm作为边缘值。... 详细信息

黄土地区土壤中全磷与有效磷含量均有由北向南逐渐趋增的趋势,一般是:灌淤土较高,(土娄)土、褐土与黑垆土次之,黄绵土、灰钙土和黑钙土又次之,风沙土较低。土壤有效磷可分为4级,5.5ppm可作为土壤缺磷临界值,5.5—10.5 ppm作为边缘值。黄土地区土壤中各形态磷占全磷比例以Ca-P最高,有机磷与O-P次之,Al-P、Fe-P和水溶磷较低。土壤有机磷及其与无机磷的比值与土壤肥力有密切关系,闭蓄态磷及其与磷酸钙的比值似与土壤风化程度有关。磷肥施入土壤后,早期固定较快,20天后渐趋平稳。在高钙土壤中,施入的磷主要转化为Ca-P,低钙土壤则转化为Ca-P,Al-P和Fe-P。黄土地区磷肥施于低肥土壤或中肥土壤中其肥效优于高肥土壤;施于灌溉土壤优于旱作土壤;与氮肥配施优于单施。

关键词：土壤磷含量分布形态转化磷肥

Distributed Matching Theory-Based Task Re-Allocating for Heterogeneous Multi-UAV Edge Computing

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China Communications 2024年第1期21卷 260-278页

作者： Yangang Wang xianglin Wei Hai Wang Yongyang Hu Kuang Zhao Jianhua Fan College of Communications Engineering Army Engineering University of PLANanjing 210007China The Sixty-Third Research Institute National University of Defense TechnologyNanjing 210007China

Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge ***,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered ***,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy *** three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making *** tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and ***,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put *** formally proved that a stable matching can be achieved by our *** simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness.

关键词： edge computing heterogeneity matching theory service function unmanned aerial vehicle

Quantifying the agreement and accuracy characteristics of four satellite-based LULC products for cropland classification in China

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Journal of Integrative Agriculture 2024年第1期23卷 283-297页

作者： Jie Xue xianglin Zhang Songchao Chen Bifeng Hu Nan Wang Zhou Shi Department of Land Management Zhejiang UniversityHangzhou 310058China Institute of Applied Remote Sensing and Information Technology College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311215China Department of Land Resource Management School of Public Finance and Public AdministrationJiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Spectroscopy Sensing Ministry of Agriculture and Rural AffairsHangzhou 310058China

Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing *** the differences in LULC classification schemes,there is a lack of research on assessing the accuracy of their application to croplands in a unified ***,this study evaluated the spatial and area accuracies of cropland classification for four commonly used global LULC products(i.e.,MCD12Q1V6,GlobCover2009,FROM-GLC and GlobeLand30)based on the harmonised FAO criterion,and quantified the relationships between four factors(i.e.,slope,elevation,field size and crop system)and cropland classification *** validation results indicated that MCD12Q1 and GlobeLand30 performed well in cropland classification regarding spatial consistency,with overall accuracies of 94.90 and 93.52%,*** FROMGLC showed the worst performance,with an overall accuracy of 83.17%.Overlaying the cropland generated by the four global LULC products,we found the proportions of complete agreement and disagreement were 15.51 and 44.72% for the cropland classification,*** consistency was mainly observed in the Northeast China Plain,the Huang-Huai-Hai Plain and the northern part of the Middle-lower Yangtze Plain,*** contrast,low consistency was detected primarily on the eastern edge of the northern and semiarid region,the Yunnan-Guizhou Plateau and southern *** size was the most important factor for mapping *** area accuracy,compared with China Statistical Yearbook data at the provincial scale,the accuracies of different products in descending order were:GlobeLand30,FROM-GLC,MCD12Q1,and *** cropland classification schemes mainly caused large area deviations among the four products,and they also resulted in the different ranks of spatial accuracy and area accuracy among the four *** results can provide valuable suggestions for selecting cropland products at the national or provinc

关键词： global LULC products cropland mapping accuracy evaluation food security China

Blast damage zone strength reduction method for deep cavern excavation and its application

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 236-251页

作者： Tianzhi YAO Zuguo MO Li QIAN Yunpeng GAO Jianhai ZHANG xianglin XING Enlong LIU Ru ZHANG State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resources and HydropowerSichuan UniversityChengdu 610065China Power China Chengdu Engineering Corporation Limited Chengdu 610072China

The drill and blast(D&B)method is widely used to excavate underground spaces,but explosions generally cause damage to the ***,no blast simulation method can provide computational accuracy and *** this paper,a blast equivalent simulation method called the blast damage zone strength reduction(BDZSR)method is *** method first calculates the range of the blast-induced damage zone(BDZ)by formulae,then reduces the strength and deformation parameters of the rock within the BDZ ahead of excavation,and finally calculates the excavation damage zone(EDZ)for the D&B method by numerical *** method combines stress wave attenuation,rock damage criteria and stress path variation to derive the BDZ depth calculation *** formulae consider the initial geo-stress,and the reliability is verified by numerical *** calculation of BDZ depth with these formulae allows the corresponding numerical simulation to avoid the time-consuming dynamic calculation process,thus greatly enhancing the calculation *** method was applied to the excavation in Jinping Class II hydropower station to verify its *** results show that the BDZSR method can be applied to blast simulation of underground caverns and provide a new way to study blast-induced damage.

关键词： attenuation of stress wave deep-buried underground building drill and blast in situ stress

A macro-mesoscopic constitutive model for porous and cracked rock under true triaxial conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3080-3098页

作者： Li Qian Zuguo Mo Jianhai Zhang xianglin Xing Ru Zhang Tianzhi Yao Yunpeng Gao State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resources and HydropowerSichuan UniversityChengdu610065China Power China Chengdu Engineering Corporation Limited Chengdu610072China

The complex mechanical and damage mechanisms of rocks are intricately tied to their diverse mineral compositions and the formation of pores and cracks under external *** rock tests reveal a complex interplay between the closure of porous defects and the propagation of induced cracks,presenting challenges in accurately representing their mechanical properties,especially under true triaxial stress *** paper proposes a conceptualization of rock at the mesoscopic level as a two-phase composite,consisting of a bonded medium matrix and frictional medium *** bonded medium is characterized as a mesoscopic elastic material,encompassing various minerals surrounding porous *** mechanical properties are determined using the mixed multi-inclusion *** of the bonded medium into the frictional medium occurs through crack extension,with its elastoplastic properties defined by the DruckerePrager yield criterion,accounting for hardening,softening,and *** and Eshelby’s equivalent inclusion methods are applied to the bonded and frictional media,*** macroscopic mechanical properties of the rock are derived from these mesoscopic ***,a True Triaxial Macro-Mesoscopic(TTMM)constitutive model is *** model effectively captures the competitive effect and accurately describes the stress-deformation characteristics of *** the TTMM model,the strains resulting from porous defect closure and induced crack extension are differentiated,enabling quantitative determination of the associated damage evolution.

关键词： Micromechanics Macroemesoscopic Homogenization Constitutive model Competitive effect

Modeling Reynolds stress anisotropy invariants via machine learning

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Acta Mechanica Sinica 2024年第6期40卷 50-63页

作者： xianglin Shan Xuxiang Sun Wenbo Cao Weiwei Zhang Zhenhua Xia School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Department of Engineering Mechanics Zhejiang UniversityHangzhou310027China

The presentation and modeling of turbulence anisotropy are crucial for studying large-scale turbulence structures and constructing turbulence ***,accurately capturing anisotropic Reynolds stresses often relies on expensive direct numerical simulations(DNS).Recently,a hot topic in data-driven turbulence modeling is how to acquire accurate Reynolds stresses by the Reynolds-averaged Navier-Stokes(RANS)simulation and a limited amount of data from *** existing studies use mean flow characteristics as the input features of machine learning models to predict high-fidelity Reynolds stresses,but these approaches still lack robust generalization *** this paper,a deep neural network(DNN)is employed to build a model,mapping from tensor invariants of RANS mean flow features to the anisotropy invariants of high-fidelity Reynolds *** the aspects of tensor analysis and input-output feature design,we try to enhance the generalization of the model while preserving invariance.A functional framework of Reynolds stress anisotropy invariants is derived *** irreducible invariants are then constructed from a tensor group,serving as alternative input features for ***,we propose a feature selection method based on the Fourier transform of periodic *** results demonstrate that the data-driven model achieves a high level of accuracy in predicting turbulence anisotropy of flows over periodic hills and converging-diverging ***,the well-trained model exhibits strong generalization capabilities concerning various shapes and higher Reynolds *** approach can also provide valuable insights for feature selection and data generation for data-driven turbulence models.

关键词： Reynolds stress Anisotropy invariant Tensor analysis Machine learning