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学者姓名：王民
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Abstract ：
针对滚珠丝杠副在低转速状态存在混合润滑导致丝杠滚道加速磨损的问题,基于等温弹流润滑理论建立了滚珠丝杠副弹流润滑接触模型研究滚珠与滚道间的摩擦机理和磨损形式.首先基于Frenet-Serret坐标转换方法建立丝杠与螺母的滚道曲面几何模型.其次基于Reynolds方程建立了滚珠丝杠副弹流润滑接触模型,求解了润滑油膜接触压力分布、油膜厚度分布和微凸体接触压力分布.最后从微观角度阐明了滚珠丝杠副的摩擦机理,其摩擦因数由微凸体接触摩擦因数和油膜润滑摩擦因数组成.实验结果表明:在低转速阶段丝杠滚道的磨损方式为黏着磨损和磨粒磨损,且模拟的摩擦因数曲线趋势和经典的Stribeck摩擦曲线趋势吻合较好,根据实测摩擦力矩准确识别了不同转速下滚珠丝杠副的摩擦因数和润滑状态.
Keyword ：
润滑状态 润滑状态 摩擦因数 摩擦因数 黏着磨损 黏着磨损 弹流润滑理论 弹流润滑理论 滚珠丝杠副 滚珠丝杠副 磨粒磨损 磨粒磨损
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| GB/T 7714 | 孙铁伟 , 王民 , 高相胜 et al. 基于等温弹流润滑理论的滚珠丝杠副摩擦机理研究 [J]. | 北京工业大学学报 , 2023 , 49 (1) : 1-10 . |
| MLA | 孙铁伟 et al. "基于等温弹流润滑理论的滚珠丝杠副摩擦机理研究" . | 北京工业大学学报 49 . 1 (2023) : 1-10 . |
| APA | 孙铁伟 , 王民 , 高相胜 , 赵英杰 . 基于等温弹流润滑理论的滚珠丝杠副摩擦机理研究 . | 北京工业大学学报 , 2023 , 49 (1) , 1-10 . |
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Abstract ：
本发明提供一种铣刀磨损监测方法及装置，该方法包括：采集铣削加工过程中机床主轴端的振动信号；选取有效铣削状态下的有效振动信号进行EEMD分解，以得到有效振动信号对应的多个IMF分量；根据各本征模态函数分量分别与有效振动信号的互信息系数和能量权重从多个IMF分量中选出主模态振动；计算所述主模态振动的瞬时幅值函数和瞬时频率函数；根据所述瞬时幅值函数和瞬时频率函数计算振动阻尼比；根据主轴旋转周期，选择旋转周期内对应的所述振动阻尼比计算一个旋转周期的平均阻尼比；以所述平均阻尼比作为铣刀磨损指标监测铣刀磨损过程，从而实现了对铣刀磨损过程有效地监测。
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| GB/T 7714 | 王民 , 杨斌 , 昝涛 et al. 铣刀磨损监测方法及装置 : CN202210292147.7[P]. | 2022-03-23 . |
| MLA | 王民 et al. "铣刀磨损监测方法及装置" : CN202210292147.7. | 2022-03-23 . |
| APA | 王民 , 杨斌 , 昝涛 , 高相胜 , 高鹏 . 铣刀磨损监测方法及装置 : CN202210292147.7. | 2022-03-23 . |
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Abstract ：
本实用新型提供了一种多关节臂超声振动脊柱钙化组织介入手术去除装置，包括沿前后方向固定连接的超声振动骨刀模块和多关节柔性臂模块；多关节柔性臂模块可弯曲运动地带动超声振动骨刀模块弯曲切割脊柱钙化骨组织。本实用新型切除效果好，效率高，出血少，能够对位置偏僻、结构复杂的脊柱钙化骨组织进行弯曲切削，减少手术风险、降低手术难度。
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| GB/T 7714 | 袁有 , 高鹏 , 金一丹 et al. 多关节臂超声振动脊柱钙化组织介入手术去除装置 : CN202223178042.3[P]. | 2022-11-25 . |
| MLA | 袁有 et al. "多关节臂超声振动脊柱钙化组织介入手术去除装置" : CN202223178042.3. | 2022-11-25 . |
| APA | 袁有 , 高鹏 , 金一丹 , 高瑞杰 , 王民 , 高相胜 et al. 多关节臂超声振动脊柱钙化组织介入手术去除装置 : CN202223178042.3. | 2022-11-25 . |
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Abstract ：
A vibration isolator based on a tunable negative stiffness mechanism combines the advantages of high-staticlow-dynamic stiffness (HSLDS) isolators to expand the isolation frequency band and variable stiffness isolators to suppress resonance. In this paper, a novel tunable negative stiffness spring using Maxwell normal stress (SMNS) is proposed. The stiffness tunable range and energy utilization efficiency are greatly improved due to the newly designed magnetic circuit. Moreover, the electromagnetic negative stiffness device has the advantages of no friction, no backlash, compact structure and easy control. An analytical model of the electromagnetic force is built based on magnetic circuit analysis, and the parameter analysis is performed. An HSLDS isolator is constructed by connecting the SMNS in parallel with a linear isolator. The stiffness and vibration isolation performance are measured. The experimental results show that the SMNS produces an online tunable negative stiffness, which expands the isolation bandwidth and significantly improves the vibration isolation performance.
Keyword ：
Electromagnetic spring Electromagnetic spring High-static-low-dynamic stiffness High-static-low-dynamic stiffness Vibration control Vibration control Tunable negative stiffness Tunable negative stiffness
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| GB/T 7714 | Yuan, Shujin , Sun, Yi , Wang, Min et al. Tunable negative stiffness spring using maxwell normal stress [J]. | INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES , 2021 , 193 . |
| MLA | Yuan, Shujin et al. "Tunable negative stiffness spring using maxwell normal stress" . | INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES 193 (2021) . |
| APA | Yuan, Shujin , Sun, Yi , Wang, Min , Ding, Jiheng , Zhao, Jinglei , Huang, Yining et al. Tunable negative stiffness spring using maxwell normal stress . | INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES , 2021 , 193 . |
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Abstract ：
A dual-mesh three characteristic lines method was proposed for stress wave propagation through a microdefected rock mass containing a thin-layer filled macrojoint. The dual-mesh three characteristic lines are composed of five basic elements that are used to calculate stress wave propagation at the boundary and the interior of the microdefected rock mass and the left side, interior and right side of the filled macrojoint. The results of the present study were compared with that of available analytical results that do not consider microdefects and do not consider microdefects and macrojoint thickness. The results show that the proposed method can be used to efficiently investigate the effect of microdefects and filled macrojoints on wave propagation. The results also show that the viscosity coefficient in the equivalent viscoelastic model of the microdefected rock mass, the viscosity coefficient in the equivalent viscoelastic model of the filled macrojoint and the thickness of the filled macrojoint have significant effects on stress wave attenuation. The transmission coefficient initially decreases and then increases as the viscosity coefficient in the equivalent viscoelastic model of the microdefected rock mass increases. The transmission coefficient increases and then tends to flatten as the viscosity coefficient in the equivalent viscoelastic model of the filled macrojoint increases. The transmission coefficient decreases as the thickness of the filled macrojoint increases.
Keyword ：
Dual-mesh three characteristic lines method Dual-mesh three characteristic lines method Rock mass Rock mass Microdefect Microdefect Stress wave propagation Stress wave propagation Filled macrojoint Filled macrojoint
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| GB/T 7714 | Fan, L. F. , Wang, M. , Du, X. L. . Dual-Mesh Three Characteristic Lines Method for Stress Wave Propagation Through a Microdefected Rock Mass with a Thin-Layer Filled Macrojoint [J]. | ROCK MECHANICS AND ROCK ENGINEERING , 2021 , 54 (12) : 6621-6632 . |
| MLA | Fan, L. F. et al. "Dual-Mesh Three Characteristic Lines Method for Stress Wave Propagation Through a Microdefected Rock Mass with a Thin-Layer Filled Macrojoint" . | ROCK MECHANICS AND ROCK ENGINEERING 54 . 12 (2021) : 6621-6632 . |
| APA | Fan, L. F. , Wang, M. , Du, X. L. . Dual-Mesh Three Characteristic Lines Method for Stress Wave Propagation Through a Microdefected Rock Mass with a Thin-Layer Filled Macrojoint . | ROCK MECHANICS AND ROCK ENGINEERING , 2021 , 54 (12) , 6621-6632 . |
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Abstract ：
Bearing fault diagnosis that utilizes motor current has shown great potential for industrial application. For estimating fault sizes, this paper develop an electromechanical-magnetic coupling computational model of induction motor (IM) based on modified winding function approach (MWFA) in order to extract the fault-excited harmonic components and amplitudes in stator current. A new evaluating indicator FHD (Fault-excited Harmonic Distortion) is then proposed to describe the specific relation between fault sizes and severity of fault-excited harmonic distortion. The statistical results show that there is a fixed functional relation curve between FHD and fault sizes in different IM. Finally, an experimental IM with a known size built-in faulted bearing is investigated. The 1 mm artificial damage on outer raceway is recognized by calculating FHD (0.5636 in average) value and comparing with the simulated relation curve. The results validate the accuracy and robustness of the proposed approach in fault size estimation. © 2020
Keyword ：
Electric fault currents Electric fault currents Harmonic analysis Harmonic analysis Induction motors Induction motors Stators Stators Ball bearings Ball bearings Harmonic distortion Harmonic distortion
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| GB/T 7714 | Wang, Chen , Wang, Min , Yang, Bin et al. A novel methodology for fault size estimation of ball bearings using stator current signal [J]. | Measurement: Journal of the International Measurement Confederation , 2021 , 171 . |
| MLA | Wang, Chen et al. "A novel methodology for fault size estimation of ball bearings using stator current signal" . | Measurement: Journal of the International Measurement Confederation 171 (2021) . |
| APA | Wang, Chen , Wang, Min , Yang, Bin , Song, Kaiyu , Zhang, Yiling , Liu, Liming . A novel methodology for fault size estimation of ball bearings using stator current signal . | Measurement: Journal of the International Measurement Confederation , 2021 , 171 . |
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Abstract ：
It is well-known that second-order optimizer can accelerate the training of deep neural networks, however, the huge computation cost of second-order optimization makes it impractical to apply in real practice. In order to reduce the cost, many methods have been proposed to approximate a second-order matrix. Inspired by KFAC, we propose a novel Trace-based Hardware-driven layer-ORiented Natural Gradient Descent Computation method, called THOR, to make the second-order optimization applicable in the real application models. Specifically, we gradually increase the update interval and use the matrix trace to determine which blocks of Fisher Information Matrix (FIM) need to be updated. Moreover, by resorting the power of hardware, we have designed a hardware-driven approximation method for computing FIM to achieve better performance. To demonstrate the effectiveness of THOR, we have conducted extensive experiments. The results show that training ResNet-50 on ImageNet with THOR only takes 66.7 minutes to achieve a top-1 accuracy of 75.9 % under an 8 Ascend 910 environment with MindSpore, a new deep learning computing framework. Moreover, with more computational resources, THOR can only takes 2.7 minutes to 75.9 % with 256 Ascend 910.
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| GB/T 7714 | Chen, Mengyun , Gao, Kaixin , Liu, Xiaolei et al. THOR, Trace-Based Hardware-Driven Layer-Oriented Natural Gradient Descent Computation [C] . 2021 : 7046-7054 . |
| MLA | Chen, Mengyun et al. "THOR, Trace-Based Hardware-Driven Layer-Oriented Natural Gradient Descent Computation" . (2021) : 7046-7054 . |
| APA | Chen, Mengyun , Gao, Kaixin , Liu, Xiaolei , Wang, Zidong , Ni, Ningxi , Zhang, Qian et al. THOR, Trace-Based Hardware-Driven Layer-Oriented Natural Gradient Descent Computation . (2021) : 7046-7054 . |
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Abstract ：
The overall dynamic mechanical behavior of a double-scale discontinuous rock mass with a nonlinear deformational macrojoint was investigated. A method of combining the split three characteristic lines with the piecewise linear displacement discontinuity model (DDM) was proposed. The method was applied to investigate the transmission coefficient of P-wave propagation normally through a double-scale discontinuous rock mass with a nonlinear deformational macrojoint. The results were verified by comparison with the results of P-wave propagation normally through a double-scale discontinuous rock mass with a linear deformational macrojoint. The results showed that for a small amplitude stress wave, the nonlinear deformational macrojoint can be simplified as a linear deformational form to study the stress wave propagation, whereas for a large amplitude stress wave, the effects of the nonlinear deformational behavior of the macrojoint must be considered. The difference of the effects of nonlinear and linear deformational macrojoints on large amplitude stress wave propagation can be overlooked in the low-frequency or high-frequency regions. In addition, when the incident stress wave amplitude and initial macrojoint stiffness are sufficiently large, the effects of the nonlinear deformational macrojoint on stress wave propagation can be overlooked, and the effects of microdefects must be considered. The influence degree of microdefects on the stress wave propagation increases with the increase of incident stress wave frequency. © 2020, Springer-Verlag GmbH Austria, part of Springer Nature.
Keyword ：
Piecewise linear techniques Piecewise linear techniques Seismic waves Seismic waves Wave propagation Wave propagation Rocks Rocks Rock mechanics Rock mechanics
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| GB/T 7714 | Fan, L.F. , Wang, M. , Wu, Z.J. . Effect of Nonlinear Deformational Macrojoint on Stress Wave Propagation Through a Double-Scale Discontinuous Rock Mass [J]. | Rock Mechanics and Rock Engineering , 2021 , 54 (3) : 1077-1090 . |
| MLA | Fan, L.F. et al. "Effect of Nonlinear Deformational Macrojoint on Stress Wave Propagation Through a Double-Scale Discontinuous Rock Mass" . | Rock Mechanics and Rock Engineering 54 . 3 (2021) : 1077-1090 . |
| APA | Fan, L.F. , Wang, M. , Wu, Z.J. . Effect of Nonlinear Deformational Macrojoint on Stress Wave Propagation Through a Double-Scale Discontinuous Rock Mass . | Rock Mechanics and Rock Engineering , 2021 , 54 (3) , 1077-1090 . |
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Abstract ：
在滚珠丝杠副运动过程中,滚珠与滚道之间的摩擦和磨损导致滚珠丝杠副精度衰退,降低其精度保持性.针对高速滚珠丝杠副螺旋线滚道接触区域的非对称性,采用传统的赫兹接触理论对丝杠和螺母滚道接触几何形状和关系的计算存在较大误差,提出了一种基于最小余能原理对高速滚珠丝杠副滚珠与滚道之间的法向接触应力进行分析计算的方法.首先,基于Frenet-Serret坐标转换公式建立滚珠丝杠副坐标系,对滚珠与滚道接触点处的接触情况进行几何描述,并通过2维插值算法重新进行网格划分以便于后续的接触力学分析;对滚珠与滚道之间的接触区域和控制方程进行离散化分析,提高数值计算的精确性;为了解决接触问题计算求解过程复杂、收敛速度缓慢,通过运用变分原理将接触问题转成极值问题,采用共扼梯度法进行循环迭代来实现快速收敛求解,提高接触数值解法的计算效率,求解出滚珠与滚道之间的接触应力分布;由于接触表面变形的计算相当于求影响系数矩阵与法向压应力之间的卷积,2维卷积运算和对应的2维快速傅里叶变换被用于求解接触问题的数值解.在数值求解中,主要的计算量集中在弹性变形的计算上,使用2维快速傅里叶变换(FFT)技术方便快速地计算接触区域弹性变形.将最小余能原理与赫兹接触理论分别用于求解光滑的球与平面之间的弹性接触应力分布,将两种计算方法得出的结果进行对比,计算数值重合度很好,验证了基于最小余能原理求解接触应力分布的正确性;基于最小余能原理分析螺旋升角对滚珠与滚道接触点处的接触面积和弹性变形的影响,并将该方法所得结果与赫兹接触理论计算结果进行对比分析,发现赫兹接触解与最小余能非赫兹接触精确解相比,随着滚珠丝杠副滚道螺旋升角的增大,丝杠与滚珠接触点A处的误差始终大于螺母与滚珠接触点B处的误差,丝杠滚道与滚珠接触点A处非赫兹解接触应力峰值逐渐变小,螺母滚道与滚珠接触点B处非赫兹解接触应力峰值逐渐增大,且接触点A处应力峰值始终大于接触点B处峰值,计算所得滚珠与滚道接触区域的面积和长短轴有所不同.最小余能原理非赫兹接触计算方法可以准确计算滚珠和滚道接触区域应力分布,并且可以全面和准确的计算滚道磨损带的宽度和深度.研究结果表明,采用最小余能非赫兹接触解可以有效提高滚珠丝杠副接触应力分布计算精度,保证滚珠丝杠副的精度保持性.
Keyword ：
共轭梯度法 共轭梯度法 滚珠丝杠副 滚珠丝杠副 赫兹接触 赫兹接触 最小余能原理 最小余能原理 接触应力 接触应力
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| GB/T 7714 | 王民 , 孙铁伟 , 董朝阳 et al. 高速滚珠丝杠副非赫兹接触应力计算 [J]. | 工程科学与技术 , 2021 , 53 (2) : 178-186 . |
| MLA | 王民 et al. "高速滚珠丝杠副非赫兹接触应力计算" . | 工程科学与技术 53 . 2 (2021) : 178-186 . |
| APA | 王民 , 孙铁伟 , 董朝阳 , 孔德顺 , 高相胜 . 高速滚珠丝杠副非赫兹接触应力计算 . | 工程科学与技术 , 2021 , 53 (2) , 178-186 . |
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Abstract ：
Mild cognitive impairment (MCI) detection using magnetic resonance image (MRI), plays a crucial role in the treatment of dementia disease at an early stage. Deep learning architecture produces impressive results in such research. Algorithms require a large number of annotated datasets for training the model. In this study, we overcome this issue by using layer-wise transfer learning as well as tissue segmentation of brain images to diagnose the early stage of Alzheimer's disease (AD). In layer-wise transfer learning, we used the VGG architecture family with pre-trained weights. The proposed model segregates between normal control (NC), the early mild cognitive impairment (EMCI), the late mild cognitive impairment (LMCI), and the AD. In this paper, 85 NC patients, 70 EMCI, 70 LMCI, and 75 AD patients access form the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Tissue segmentation was applied on each subject to extract the gray matter (GM) tissue. In order to check the validity, the proposed method is tested on preprocessing data and achieved the highest rates of the classification accuracy on AD vs NC is 98.73%, also distinguish between EMCI vs LMCI patients testing accuracy 83.72%, whereas remaining classes accuracy is more than 80%. Finally, we provide a comparative analysis with other studies which shows that the proposed model outperformed the state-of-the-art models in terms of testing accuracy.
Keyword ：
Transfer learning Transfer learning Image classification Image classification Early diagnosis Early diagnosis Alzheimer’s disease Alzheimer’s disease
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| GB/T 7714 | Mehmood Atif , Yang Shuyuan , Feng Zhixi et al. A Transfer Learning Approach for Early Diagnosis of Alzheimer's Disease on MRI Images. [J]. | Neuroscience , 2021 , 460 : 43-52 . |
| MLA | Mehmood Atif et al. "A Transfer Learning Approach for Early Diagnosis of Alzheimer's Disease on MRI Images." . | Neuroscience 460 (2021) : 43-52 . |
| APA | Mehmood Atif , Yang Shuyuan , Feng Zhixi , Wang Min , Ahmad Al Smadi , Khan Rizwan et al. A Transfer Learning Approach for Early Diagnosis of Alzheimer's Disease on MRI Images. . | Neuroscience , 2021 , 460 , 43-52 . |
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