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Online Detection of Broken Rotor Bar Fault in Induction Motors by Combining Estimation of Signal Parameters via Min-norm Algorithm and Least Square Method 被引量:4
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作者 Pan-Pan Wang Qiang Yu +1 位作者 Yong-Jun Hu Chang-Xin Miao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第6期1285-1295,共11页
Current research in broken rotor bar (BRB) fault detection in induction motors is primarily focused on a high-frequency resolution analysis of the stator current. Compared with a discrete Fourier transformation, the... Current research in broken rotor bar (BRB) fault detection in induction motors is primarily focused on a high-frequency resolution analysis of the stator current. Compared with a discrete Fourier transformation, the parametric spectrum estimation technique has a higher frequency accuracy and resolution. However, the existing detection methods based on parametric spectrum estima- tion cannot realize online detection, owing to the large computational cost. To improve the efficiency of BRB fault detection, a new detection method based on the min-norm algorithm and least square estimation is proposed in this paper. First, the stator current is filtered using a band-pass filter and divided into short overlapped data windows. The min-norm algorithm is then applied to determine the fre- quencies of the fundamental and fault characteristic com- ponents with each overlapped data window. Next, based on the frequency values obtained, a model of the fault current signal is constructed. Subsequently, a linear least squares problem solved through singular value decomposition is designed to estimate the amplitudes and phases of the related components. Finally, the proposed method is applied to a simulated current and an actual motor, the results of which indicate that, not only parametric spectrum estimation technique. 展开更多
关键词 Fault detection broken rotor bars Min-norm Least squares method Induction motors
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Broken Rotor Bar Fault Diagnosis of Induction Motors Using a Hybrid Bare-bones Particle Swarm Optimization Algorithm 被引量:10
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作者 WANG Panpan SHI Liping ZHANG Yong HAN Li 《中国电机工程学报》 EI CSCD 北大核心 2012年第30期I0011-I0011,13,共1页
在传统定子电流频谱分析中,感应电机转子断条故障特征经常被基波分量淹没而无法准确检测。针对该问题,提出一种基于混合骨干微粒群优化算法的转子断条故障诊断新方法。该方法首先根据电流信号与单位余弦基函数的内积最大准则,利用混合... 在传统定子电流频谱分析中,感应电机转子断条故障特征经常被基波分量淹没而无法准确检测。针对该问题,提出一种基于混合骨干微粒群优化算法的转子断条故障诊断新方法。该方法首先根据电流信号与单位余弦基函数的内积最大准则,利用混合骨干微粒群算法强大的全局搜索能力,准确估计出基波波形参数;然后利用波形参数构造出基波表达式,并将其从原电流信号中剔除,达到突出故障特征的目的。针对微粒群算法在进化后期收敛缓慢的缺点,通过K–均值聚类方式,引入单纯形法对其进行改进,使整个算法的广度探索与深度开发能力得到了有效均衡。最后,对模拟数据和实测信号进行实验,结果验证了所提方法的有效性和优越性。 展开更多
关键词 转子断条故障 混合粒子群优化算法 故障诊断 异步电动机 感应电机 故障发生
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IBPSO-Based MUSIC Algorithm for Broken Rotor Bars Fault Detection of Induction Motors 被引量:3
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作者 Pan-Pan Wang Xiao-Xiao Chen +2 位作者 Yong Zhang Yong-Jun Hu Chang-Xin Miao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第5期48-57,共10页
In spectrum analysis of induction motor current, the characteristic components of broken rotor bars(BRB) fault are often submerged by the fundamental component. Although many detection methods have been proposed for... In spectrum analysis of induction motor current, the characteristic components of broken rotor bars(BRB) fault are often submerged by the fundamental component. Although many detection methods have been proposed for this problem, the frequency resolution and accuracy are not high enough so that the reliability of BRB fault detection is a ected. Thus, a new multiple signal classification(MUSIC) algorithm based on particle swarm intelligence search is developed. Since spectrum peak search in MUSIC is a multimodal optimization problem, an improved bare?bones particle swarm optimization algorithm(IBPSO) is proposed first. In the IBPSO, a modified strategy of subpopulation determination is introduced into BPSO for realizing multimodal search. And then, the new MUSIC algorithm, called IBPSO?based MUSIC, is proposed by replacing the fixed?step traversal search with IBPSO. Meanwhile, a simulation signal is used to test the e ectiveness of the proposed algorithm. The simulation results show that its frequency precision reaches 10-5, and the computational cost is only comparable to that of traditional MUSIC with 0.1 search step. Finally, the IBPSO?based MUSIC is applied in BRB fault detection of an induction motor, and the e ectiveness and superiority are proved again. The proposed research provides a modified MUSIC algorithm which has su cient frequency precision to detect BRB fault in induction motors. 展开更多
关键词 MUSIC MULTIMODAL bare?bones particle swarm optimization Induction motors broken rotor bars Fault detection
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A Fault Diagnosis Approach for Broken Rotor Bars Based on EMD and Envelope Analysis 被引量:5
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作者 ZHANG Jian-wen ZHU Ning-hui YANO Li YAO Qi LU Qing 《Journal of China University of Mining and Technology》 EI 2007年第2期205-209,共5页
Empirical Mode Decomposition (EMD) used to deal with non-linear and non-stable signals,is a time-frequency analytical method that has been developed recently. In this paper the EMD method is used to filter the noise f... Empirical Mode Decomposition (EMD) used to deal with non-linear and non-stable signals,is a time-frequency analytical method that has been developed recently. In this paper the EMD method is used to filter the noise from the stator current signal that arises when rotor bars break. Then a Hilbert Transform is used to extract the envelope from the filtered signal. With the EMD method again,the frequency band containing the fault characteris-tic-frequency components,2sf,can be extracted from the signal's envelope. The last step is to use a Fast Fourier Trans-form (FFT) method to extract the fault characteristic frequency. This frequency can be detected in actual data from a faulty motor,as shown by example. Compared to the Extend Park Vector method this method is proved to be more sen-sitive under light motor load. 展开更多
关键词 EMD analysis of envelope fault of broken rotor bar
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Broken Rotor Bar Fault Detection of Induction Motors Using a Joint Algorithm of Trust Region and Modified Bare-bones Particle Swarm Optimization 被引量:1
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作者 Panpan Wang Liping Shi +2 位作者 Yong Zhang Yifan Wang Li Han 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2019年第1期65-78,共14页
A precise detection of the fault feature parameter of motor current is a new research hotspot in the broken rotor bar(BRB) fault diagnosis of induction motors. Discrete Fourier transform(DFT) is the most popular techn... A precise detection of the fault feature parameter of motor current is a new research hotspot in the broken rotor bar(BRB) fault diagnosis of induction motors. Discrete Fourier transform(DFT) is the most popular technique in this field, owing to low computation and easy realization. However, its accuracy is often limited by the data window length, spectral leakage, fence e ect, etc. Therefore, a new detection method based on a global optimization algorithm is proposed. First, a BRB fault current model and a residual error function are designed to transform the fault parameter detection problem into a nonlinear least-square problem. Because this optimization problem has a great number of local optima and needs to be resolved rapidly and accurately, a joint algorithm(called TR-MBPSO) based on a modified bare-bones particle swarm optimization(BPSO) and trust region(TR) is subsequently proposed. In the TR-MBPSO, a reinitialization strategy of inactive particle is introduced to the BPSO to enhance the swarm diversity and global search ability. Meanwhile, the TR is combined with the modified BPSO to improve convergence speed and accuracy. It also includes a global convergence analysis, whose result proves that the TR-MBPSO can converge to the global optimum with the probability of 1. Both simulations and experiments are conducted, and the results indicate that the proposed detection method not only has high accuracy of parameter estimation with short-time data window, e.g., the magnitude and frequency precision of the fault-related components reaches 10^(-4), but also overcomes the impacts of spectral leakage and non-integer-period sampling. The proposed research provides a new BRB detection method, which has enough precision to extract the parameters of the fault feature components. 展开更多
关键词 Fault detection broken rotor barS Induction motors bare-bones particle SWARM optimization Trust region
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供电电压闪变对异步电动机转子故障在线检测的影响及应对
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作者 许伯强 孙丽玲 《中国电机工程学报》 EI CSCD 北大核心 2024年第11期4525-4534,I0030,共11页
供电电压闪变可能对异步电动机转子故障在线检测产生不利影响,导致基于定子电流信号分析(motor current signature analysis,MCSA)的转子故障在线检测方法失效。通过理论分析,揭示供电电压闪变恶化转子故障在线检测性能的机制。提出免... 供电电压闪变可能对异步电动机转子故障在线检测产生不利影响,导致基于定子电流信号分析(motor current signature analysis,MCSA)的转子故障在线检测方法失效。通过理论分析,揭示供电电压闪变恶化转子故障在线检测性能的机制。提出免于供电电压闪变影响的异步电动机转子故障在线检测方法,首先,根据转子故障主特征频率分量预判转子健康或故障;继而,根据转子故障独有的辅助特征频率分量进一步确认转子健康或故障。仿真与实验结果证明了该方法的有效性。 展开更多
关键词 异步电动机 转子故障 转子断条 供电电压闪变 在线检测
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基于小波包能量分析和信号融合的异步电机转子故障诊断 被引量:1
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作者 张雅晖 杨凯 杨帆 《电测与仪表》 北大核心 2024年第4期161-168,共8页
为提高异步电机转子故障诊断的可靠性,文中介绍了一种基于小波包能量分析和信号融合的异步电机转子故障诊断方法。采用定子电流信号和振动信号的频谱特征融合作为转子断条以及气隙偏心故障的诊断依据,首先对信号进行小波包分解,获得不... 为提高异步电机转子故障诊断的可靠性,文中介绍了一种基于小波包能量分析和信号融合的异步电机转子故障诊断方法。采用定子电流信号和振动信号的频谱特征融合作为转子断条以及气隙偏心故障的诊断依据,首先对信号进行小波包分解,获得不同小波包频带节点下对应的能量分布,并与正常电机信号进行比较,进而对能量异常的信号频段进行小波包节点重构,最后通过快速傅里叶变换识别故障特征频率,诊断电机故障是否发生。通过仿真分析,验证了该方法的有效性和实用性,对于电机运行状态的准确监测具有重要意义。 展开更多
关键词 故障诊断 异步电机 转子断条 气隙偏心 小波包分析 信号融合
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Anisotropic surface broken bond properties and wettability of calcite and fluorite crystals 被引量:19
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作者 高志勇 孙伟 +1 位作者 胡岳华 刘晓文 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第5期1203-1208,共6页
Anisotropic surface broken bond densities of six different surfaces of calcite and three surfaces of fluorite were calculated. In terms of the calculated results, the commonly exposed surfaces of the two minerals were... Anisotropic surface broken bond densities of six different surfaces of calcite and three surfaces of fluorite were calculated. In terms of the calculated results, the commonly exposed surfaces of the two minerals were predicted and the relations between surface broken bonds densities and surface energies were analyzed. Then the anisotropic wettability of the commonly exposed surfaces was studied by means of contact angle measurement. The calculation results show that the (101^-4), (213^-4)and (01 1^-8)surfaces for calcite and (111) for fluorite are the most commonly exposed surfaces and there is a good rectilinear relation between surface broken bond density and surface energy with correlation of determination (R^2) of 0.9613 and 0.9969, respectively. The anisotropic wettability of different surfaces after immersing in distilled water and sodium oleate solutions at different concentrations can be explained by anisotropic surface broken bond densities and active Ca sites densities, respectively. 展开更多
关键词 CALCITE FLUORITE surface broken bonds CLEAVAGE surface energy contact angle WETTABILITY
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Mineral cleavage nature and surface energy: Anisotropic surface broken bonds consideration 被引量:18
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作者 高志勇 孙伟 胡岳华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第9期2930-2937,共8页
The population of surface broken bonds of some typical sulfide, oxide and salt-type minerals which may belong to cubic, tetragonal, hexagonal, or orthorhombic system, were calculated. In terms of the calculation resul... The population of surface broken bonds of some typical sulfide, oxide and salt-type minerals which may belong to cubic, tetragonal, hexagonal, or orthorhombic system, were calculated. In terms of the calculation results, the cleavage natures of these minerals were analyzed, and the relationship between surface broken bonds density and surface energy was also established. The results show that the surface broken bonds properties could be used to predict the cleavage nature of most of minerals, and the predicted cleavage planes agree well with those reported in previous literature. Moreover, this work explored a rule that, surface broken bonds density is directly related to surface energy with determination coefficient(R2) of over 0.8, indicating that the former is a dominant factor to determine the latter. Therefore, anisotropic surface broken bonds density can be used to predict the stability of mineral surface and the reactivity of surface atoms. 展开更多
关键词 surface broken bonds CLEAVAGE surface energy pyrite SPHALERITE CASSITERITE rutile HEMATITE
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不同水文模型在Broken流域的比较研究 被引量:2
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作者 张卫华 李雨 +1 位作者 魏朝富 靳军英 《西南师范大学学报(自然科学版)》 CAS CSCD 北大核心 2011年第4期211-216,共6页
流域水文模型对流域产汇流计算、洪水分析与预报以及水资源优化配置与调度等具有重大意义.本文选用三种比较常见的流域水文模型,介绍了各模型的结构、计算过程、应用范围等;随后将三个模型运用在澳大利亚Broken流域并且利用1966—1995... 流域水文模型对流域产汇流计算、洪水分析与预报以及水资源优化配置与调度等具有重大意义.本文选用三种比较常见的流域水文模型,介绍了各模型的结构、计算过程、应用范围等;随后将三个模型运用在澳大利亚Broken流域并且利用1966—1995年的日降雨、径流和蒸散发数据进行降雨产流分析.结果表明:Nash-Sutcliffe的效率系数均达到了80%以上,径流总量相对误差系数RE对于萨克拉门托模型和SIMHYD模型均在10%以内,而Tank模型的检验期超出了10%.通过对三个模型运用结果的分析和比较,SIMHYD模型是适合于该流域的最理想的流域水文模型. 展开更多
关键词 水文模型 broken流域 评价标准 比较研究
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Development and application of novel high‐efficiency composite ultrafine cement grouts for roadway in fractured surrounding rocks 被引量:1
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作者 Maolin Tian Shaojie Chen +1 位作者 Lijun Han Hongtian Xiao 《Deep Underground Science and Engineering》 2024年第1期53-69,共17页
The fractured surrounding rocks of roadways pose major challenges to safe mining.Grouting has often been used to reinforce the surrounding rocks to mitigate the safety risks associated with fractured rocks.The aim of ... The fractured surrounding rocks of roadways pose major challenges to safe mining.Grouting has often been used to reinforce the surrounding rocks to mitigate the safety risks associated with fractured rocks.The aim of this study is to develop highly efficient composite ultrafine cement(CUC)grouts to reinforce the roadway in fractured surrounding rocks.The materials used are ultrafine cement(UC),ultrafine fly ash(UF),ultrafine slag(US),and additives(superplasticizer[SUP],aluminate ultrafine expansion agent[AUA],gypsum,and retarder).The fluidity,bleeding,shrinkage,setting time,chemical composition,microstructure,degree of hydration,and mechanical property of grouting materials were evaluated in this study.Also,a suitable and effective CUC grout mixture was used to reinforce the roadway in the fractured surrounding rock.The results have shown that the addition of UF and US reduces the plastic viscosity of CUC,and the best fluidity can be obtained by adding 40%UF and 10%US.Since UC and UF particles are small,the pozzolanic effect of UF promotes the hydration reaction,which is conductive to the stability of CUC grouts.In addition,fine particles of UC,UF,and US can effectively fill the pores,while the volumetric expansion of AUA and gypsum decreases the pores and thus affects the microstructure of the solidified grout.The compressive test results have shown that the addition of specific amounts of UF and US can ameliorate the mechanical properties of CUC grouts.Finally,the CUC22‐8 grout was used to reinforce the No.20322 belt roadway.The results of numerical simulation and field monitoring have indicated that grouting can efficaciously reinforce the surrounding rock of the roadway.In this research,high‐performance CUC grouts were developed for surrounding rock reinforcement of underground engineering by utilizing UC and some additives. 展开更多
关键词 broken surrounding rock composite ultrafine cement(CUC)grouts grouting material grouting performance grouting reinforcement
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SCOURS IN FRONT OF A BREAKWATER BY BROKEN WAVES AND THEIR SIMILARITY LAW 被引量:2
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作者 高学平 张亚 《Transactions of Tianjin University》 EI CAS 2001年第1期12-16,共5页
The sea bottom in front of a breakwater is scoured under the action of broken waves,and this will affect the stability of the breakwater.In this paper,the scours of sandy seabed in front of a breakwater under the acti... The sea bottom in front of a breakwater is scoured under the action of broken waves,and this will affect the stability of the breakwater.In this paper,the scours of sandy seabed in front of a breakwater under the action of broken waves are investigated experimentally.The depth and range of the scouring trough at the foot of a breakwater are studied,and the influence of open foundation-bed on scouring and depositing is also discussed.In order to apply the research results to practical projects,the scale of model sediment and the scale of scours and depositions are suggested. 展开更多
关键词 broken waves BREAKWATER open foundation-bed scouring and depositing sandy seabed model similarity law
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基于Attention-CNN的振动信号电机转子断条识别
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作者 申海锋 石颉 +1 位作者 杜国庆 吴宏杰 《电气工程学报》 CSCD 北大核心 2024年第2期9-15,共7页
针对基于振动信号的转子断条诊断技术依赖于人工特征选择,泛化能力差,以及常规卷积神经网络(Convolution neural network,CNN)模型在对时序信号自动特征提取时忽略序列信息的问题,利用Attention机制对局部特征在整体表达时的度量能力,... 针对基于振动信号的转子断条诊断技术依赖于人工特征选择,泛化能力差,以及常规卷积神经网络(Convolution neural network,CNN)模型在对时序信号自动特征提取时忽略序列信息的问题,利用Attention机制对局部特征在整体表达时的度量能力,提出了一种Attention-CNN网络模型。首先通过Attention在原始信号上分配注意力,其次结合CNN进行特征提取构建网络,然后利用粒子群优化算法(Particle swarm optimization,PSO)进行网络超参数寻优,训练转子断条识别模型,最后从整体和局部两个方面进行模型评价。试验结果表明,所提出的识别模型能够达到传统诊断水平,且泛化能力高于现有方法,更适用于通过振动信号进行电机转子断条识别。 展开更多
关键词 Attention-CNN 振动信号 转子断条 泛化能力
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融合TKEO和Goerztel算法的感应电机转子断条故障诊断
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作者 王照伟 郭雯君 +1 位作者 宋向金 赵文祥 《电工技术学报》 EI CSCD 北大核心 2024年第12期3679-3690,共12页
针对电机电流信号特征分析进行转子断条故障诊断时,在低负载工况或早期,转子断条故障存在故障特征微弱以及难以分离等问题,同时需借助速度传感器获取转速信息,增加了硬件成本,该文提出了融合Teager-Kaiser能量算子(TKEO)和Goertzel算法... 针对电机电流信号特征分析进行转子断条故障诊断时,在低负载工况或早期,转子断条故障存在故障特征微弱以及难以分离等问题,同时需借助速度传感器获取转速信息,增加了硬件成本,该文提出了融合Teager-Kaiser能量算子(TKEO)和Goertzel算法的感应电机转子断条故障诊断方法。首先,采用Teager-Kaiser能量算子对定子电流进行解调处理,将基频分量转化为直流分量并去除,实现边带故障特征分量到转子断条故障特征分量以及固有偏心谐波分量到转子速度谐波分量的转变,抑制基频频谱泄露对故障诊断和转速估计造成的干扰;其次,利用Goertzel算法对归一化解调信号进行频谱分析,完成转子断条故障特征分量和转子速度谐波分量的快速提取,进而实现不同负载和不同严重程度工况下转子断条的故障诊断。此外,与归一化频域能量算子进行比较,分析其计算效率和稳定性。实验结果表明,所提方法在不同负载和不同严重程度工况下均能够有效地识别转子断条故障特征分量,并且计算量少、可靠性高、实时性强以及硬件成本低。 展开更多
关键词 转子断条 GOERTZEL算法 固有偏心 Teager-Kaiser能量算子 归一化频域能量算子
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一起火电厂循环水泵电动机电流波动案例分析
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作者 马建胜 赵建利 +1 位作者 赵予新 刘芳芳 《电气技术》 2024年第8期75-80,共6页
高压异步电动机常见的故障有转子断条裂纹及偏心,故障时定子电流表现出持续波动的特征。本文对某600MW级火电厂2B循环水泵电动机电流进行时域及频域计算与分析,确认电动机转子存在断条裂纹缺陷,并利用广义解调法对电动机电流特征分析(MC... 高压异步电动机常见的故障有转子断条裂纹及偏心,故障时定子电流表现出持续波动的特征。本文对某600MW级火电厂2B循环水泵电动机电流进行时域及频域计算与分析,确认电动机转子存在断条裂纹缺陷,并利用广义解调法对电动机电流特征分析(MCSA)结果进行验证;利用转子存在缺陷或故障时定子电流波动的特征,建立基于分布式控制系统(DCS)运行数据的异步电动机电流波动预警算法,并利用该故障电动机的历史电流数据进行验证,结果表明电动机转子断条的持续劣化能够有效地触发预警。 展开更多
关键词 异步电动机 电流波动 转子断条 电流波动预警
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The Application of "Broken Window Theory" to College's Daily Management
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作者 肖凤华 《海外英语》 2013年第4X期30-32,共3页
The daily management of college on the one hand is to constrain the action of students to achieve the maintenance of school's order and on the other hand is to help students develop good habits and remold certain ... The daily management of college on the one hand is to constrain the action of students to achieve the maintenance of school's order and on the other hand is to help students develop good habits and remold certain concepts of laws,morality and discipline to finally achieve the goal of education.This paper employed a famous theory of management,that is,the"broken win dow theory"in the research and finally concluded that the application of"broken window theory"in the daily management of colleges can immediately and effectively prevent some of students'bad behaviors and habits from being spread. 展开更多
关键词 broken WINDOW THEORY COLLEGES DAILY management
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The Application of“Broken Window Theory”to College's Daily Management
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作者 肖凤华 《海外英语》 2013年第2X期286-288,共3页
The daily management of college on the one hand is to constrain the action of students to achieve the maintenance of school's order and on the other hand is to help students develop good habits and remold certain ... The daily management of college on the one hand is to constrain the action of students to achieve the maintenance of school's order and on the other hand is to help students develop good habits and remold certain concepts of laws, morality and discipline to finally achieve the goal of education. This paper employed a famous theory of management, that is, the"broken window theory"in the research and finally concluded that the application of"broken window theory"in the daily management of colleges can immediately and effectively prevent some of students'bad behaviors and habits from being spread. 展开更多
关键词 broken WINDOW THEORY COLLEGES DAILY management
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Reconstruction of broken Si–O–Si bonds in iron ore tailings (IOTs) in concrete 被引量:12
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作者 Juan-hong Liu Yu-cheng Zhou +1 位作者 Ai-xiang Wu Hong-jiang Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第10期1329-1336,共8页
This paper reports a study on the reconstruction of broken Si O Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on th... This paper reports a study on the reconstruction of broken Si O Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The dif- ferences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and ener- gy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/Si atom ratios in the ITZs of IOTs con- crete samples are lower than those of limestone concrete;the diffraction peak of the calcium silicate phase at 2θ = 29.5°, as well as the bands of Si O bonds shifting to lower wavenumbers, indicates reconstruction of the broken Si-O-Si bonds on the surfaces of IOTs with Ca(OH)2. 展开更多
关键词 iron ore TAILINGS broken SI O SI BONDS ALKALINE environment RECONSTRUCTION
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Deformation characteristics of surrounding rock of broken and soft rock roadway 被引量:26
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作者 WANG Jin-xi LIN Ming-yue +1 位作者 TIAN Duan-xin ZHAO Cun-liang 《Mining Science and Technology》 EI CAS 2009年第2期205-209,共5页
A similar material model and a numerical simulation were constructed and are described herein. The deformation and failure of surrounding rock of broken and soft roadway are studied by using these models. The deformat... A similar material model and a numerical simulation were constructed and are described herein. The deformation and failure of surrounding rock of broken and soft roadway are studied by using these models. The deformation of the roof and floor, the relative deformation of the two sides and the deformation of the deep surrounding rock are predicted using the model. Measurements in a working mine are compared to the results of the models. The results show that the surrounding rock shows clear theological features under high stress conditions. Deformation is unequally distributed across the whole section. The surrounding rock exhibited three deformation stages: displacement caused by stress concentration, theological displacement after the digging effects had stabilized and displacement caused by supporting pressure of the roadway. Floor heave was serious, accounting for 65% of the total deformation of the roof and floor. Floor heave is the main reason for failure of the surrounding rock. The reasons for deformation of the surrounding rock are discussed based on the similar material and numerical simulations. 展开更多
关键词 soft rock roadway broken surrounding rock similarity simulation numerical simulation deformation characteristics
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Discrete element modeling of ice loads on ship hulls in broken ice fields 被引量:12
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作者 JI Shunying LI Zilin +1 位作者 LI Chunhua SHANG Jie 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第11期50-58,共9页
Ice loads on a ship hull affect the safety of the hull structure and the ship maneuvering performance in ice-covered regions. A discrete element method (DEM) is used to simulate the interaction between drifting ice ... Ice loads on a ship hull affect the safety of the hull structure and the ship maneuvering performance in ice-covered regions. A discrete element method (DEM) is used to simulate the interaction between drifting ice floes and a moving ship. The pancake ice floes are modelled with three-dimensional (3-D) dilated disk elements considering the buoyancy, drag force and additional mass induced by the current. The ship hull is modelled with 3D disks with overlaps. Ice loads on the ship hull are determined through the contact detection between ice floe element and ship hull element and the contact force calculation. The influences of different ice conditions (current velocities and directions, ice thicknesses, concentrations and ice floe sizes) and ship speeds are also examined on the dynamic ice force. The simulated results are compared qualitatively well with the existing field data and other numerical results. This work can be helpful in the shil3 structure design and the navigation securitv in ice-covered fields. 展开更多
关键词 ice load ship hull discrete element method broken ice
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