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机器学习参与山区村落影像点云分类的研究

激光技术 2024年第2期48卷 288-294页

作者：李霞杨正维黄俊伟杨亚复高莎云南省水利水电勘测设计研究院昆明650093 昆明理工大学国土资源工程学院昆明650500

为了利用点云技术更好地获取地表信息,用无人机AA1300的内置光学镜头采集影像数据,构建2-D的数字正射影像地图(DOM),悬挂GS-1350N镜头采集3-D的激光雷达点云;通过k最近邻法(KNN)、支持向量机法(SVM)和随机森林法(RF)来实现DOM分类,用定... 详细信息

为了利用点云技术更好地获取地表信息,用无人机AA1300的内置光学镜头采集影像数据,构建2-D的数字正射影像地图(DOM),悬挂GS-1350N镜头采集3-D的激光雷达点云;通过k最近邻法(KNN)、支持向量机法(SVM)和随机森林法(RF)来实现DOM分类,用定量分析中精度高的方法分类3-D点云,并进行了2-D和3-D的分类映射对比分析。结果表明,2-D的DOM分类中,相对于KNN和SVM,RF的kappa系数分别高3.74%和2.16%,全局精度分别高4.04%和2.88%;2-D的分类结果通过直接线性变换到3-D点云中,可实现2-D和3-D的点云分类,映射精度达94.15%;而在相同条件下,相对于2-D/3-D点云映射,直接3-D点云分类能更完整地呈现地物信息。3-D点云的精准分类对获取地表信息是有帮助的。

关键词：激光技术图像处理机器学习随机森林分类法高原山区乡村

CCl4诱导的肝纤维化大鼠模型肝小叶内卵圆细胞总体积与轮廓数密度变化的体视学分析

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临床肝胆病杂志 2024年第1期40卷 70-75页

作者：王川林刘全明杨霞杨正伟梅小平彭彬川北医学院附属医院感染科四川南充637000 川北医学院临床医学系四川南充637000 川北医学院基础医学与法医学研究所四川南充637000

目的定量研究CCl4诱导的肝纤维化大鼠肝小叶内卵圆细胞(HOC)总体积和轮廓数密度的变化。方法将11只雄性健康SD大鼠随机分为对照组(n=5)、肝纤维化组(n=6),每周2次皮下注射CCl4与橄榄油混悬液,每次3 mL/kg。在肝纤维化造模5周后取材,... 详细信息

目的定量研究CCl4诱导的肝纤维化大鼠肝小叶内卵圆细胞(HOC)总体积和轮廓数密度的变化。方法将11只雄性健康SD大鼠随机分为对照组(n=5)、肝纤维化组(n=6),每周2次皮下注射CCl4与橄榄油混悬液,每次3 mL/kg。在肝纤维化造模5周后取材,从每只大鼠肝脏随机抽选5个大小约1 mm3的肝组织块分别制作1张Epon812环氧树脂包埋超薄切片,运用体视学方法结合透射电子显微镜技术,对大鼠肝小叶内的HOC总体积和轮廓数密度进行定量研究,另从每只大鼠剩余肝脏等距随机抽选4个2 mm厚的肝组织块并分别制作2张石蜡包埋的Masson染色切片,按照肝纤维化Metavir分期标准定性评估每只大鼠的肝纤维化程度。计量资料两组间比较采用成组t检验。结果体视学定量研究显示,对照组肝小叶内HOC总体积为(15.40±7.63) mm3,肝纤维化组肝小叶内HOC总体积为(146.80±114.00) mm3,与对照组比较,肝纤维化组大鼠肝小叶内HOC总体积显著增加了8.53倍(t=-2.551,P=0.031);对照组肝小叶内HOC轮廓数密度为(56.20±40.40),肝纤维化组肝小叶内HOC轮廓数密度为(566.50±317.00),与对照组比较,肝纤维化组大鼠肝小叶内轮廓数密度显著增加了9.08倍(t=-3.539,P=0.006);定性观察研究结果显示,肝纤维化大鼠肝纤维化分期按照Metavir评分标准达到Ⅱ~Ⅲ期,大鼠窦周隙内肝星状细胞增生部位周围伴随着HOC的大量增生。结论 CCl4诱导肝纤维化大鼠肝小叶内HOC显著增生。

关键词：肝纤维化大鼠 Sprague-Dawley 肝卵圆细胞肝星状细胞

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米诺环素对脊神经结扎大鼠脊髓内M1/M2型小胶质细胞极化的影响

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陆军军医大学学报 2024年第15期46卷 1740-1750页

作者：成志红冯松王霞倪锐男郭洋向宇杨正伟彭彬川北医学院基础医学与法医学研究所四川南充637000 达州市第三人民医院神经外科四川达州635000 川北医学院临床医学院四川南充637000

目的探讨米诺环素(minocycline,Mino)对脊神经结扎(spinal nerve ligation,SNL)致神经病理性疼痛(neuropathic pain,NP)大鼠脊髓内M1型(促炎型)和M2型(抗炎型)小胶质细胞极化的影响及其机制。方法36只成年雄性SD大鼠按体质量分层随机抽... 详细信息

目的探讨米诺环素(minocycline,Mino)对脊神经结扎(spinal nerve ligation,SNL)致神经病理性疼痛(neuropathic pain,NP)大鼠脊髓内M1型(促炎型)和M2型(抗炎型)小胶质细胞极化的影响及其机制。方法36只成年雄性SD大鼠按体质量分层随机抽样分为Sham组、SNL组和M+SNL组(鞘内注射米诺环素),于术前1 d和术后14 d内测定大鼠后足机械痛阈值和冷痛敏阈值。术后14 d于L5脊髓取材,采用免疫组化技术和体视学技术检测L5脊髓背角内小胶质细胞的总数以及M1/M2型小胶质细胞的数量;利用生物信息学技术筛选出脊髓小胶质细胞内的核心靶点Cst7,并采用Western blot检测小胶质细胞标志物Iba-1、M1型小胶质细胞标志物iNOS、M2型小胶质细胞标志物CD206、Cst7基因编码的蛋白质胱抑素F(cystatin F,CF)及CatS/CX3CL1/CX3CR1通路蛋白的表达水平;采用ELISA检测脊髓内TNF-α、IL-6和IL-10的蛋白表达量。结果M+SNL组大鼠术后7~14 d手术侧的机械痛和冷痛敏阈值均比SNL组显著升高(P<0.01)。SNL组大鼠手术侧脊髓背角内小胶质细胞的总数,M1型、M2型小胶质细胞的数量以及脊髓CatS、CX3CL1、CX3CR1、TNF-α、IL-6和IL-10蛋白表达较Sham组均显著增加,而CF含量显著降低(P<0.01);与SNL组比较,M+SNL组小胶质细胞的总数、M1型小胶质细胞的数量以及CatS、CX3CL1、CX3CR1、TNF-α、IL-6蛋白表达均显著减少,而M2型小胶质细胞的数量以及CF、IL-10的蛋白表达均显著增加(P<0.05)。结论米诺环素改善SNL致神经病理性疼痛的机制可能是通过上调小胶质细胞内CF蛋白表达,进而抑制CatS/CX3CL1/CX3CR1信号通路,促进小胶质细胞由M1型向M2型转化,以平衡M1/M2小胶质细胞极化失衡、减轻神经炎症。

关键词：米诺环素胱抑素F 小胶质细胞脊神经结扎神经病理性疼痛体视学大鼠

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基于功率键合图理论的仿生馈能减震座椅设计

扬州大学学报（自然科学版） 2024年第2期27卷 1-8页

作者：吴倩雯关栋杨征葳扬州大学机械工程学院江苏扬州225127 中国北方车辆研究所北京100072

为有效衰减工程机械车辆的低频振动,设计了一种应用于重型车辆的馈能减震座椅.首先,模仿袋鼠下肢骨骼的多连杆串联结构设计“X”型减震结构;其次,利用功率键合图建立减震座椅模型,通过MATLAB/Simulink模块进行数值仿真;最后,采用SolidWo... 详细信息

为有效衰减工程机械车辆的低频振动,设计了一种应用于重型车辆的馈能减震座椅.首先,模仿袋鼠下肢骨骼的多连杆串联结构设计“X”型减震结构;其次,利用功率键合图建立减震座椅模型,通过MATLAB/Simulink模块进行数值仿真;最后,采用SolidWorks建立三维模型,导入ADAMS进行运动仿真,并与数值仿真结果进行对比分析.仿真结果表明:振动频率越大,能量回收系统的输出功率越高;当振动频率为2 Hz时,峰值输出功率为0.75 W,能够为车辆内各传感器供电,进而实现减震和馈能.该设计为减震座椅的馈能特性研究提供了新思路.

关键词：减震座椅功率键合图仿真仿生

Inspection Detectability Improvement for Metal Defects Detected by Pulsed Infrared Thermography

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Photonic Sensors 2019年第2期9卷 142-150页

作者： zhengwei yang Guangjie KOU Yin LI Gan TIAN Wei ZHANG Rocket Force University of Engineering Xi'an 710025China School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049China

Aiming at the drawbacks of low contrast and high noise in the thermal images, a novel method based on the combination of the thermal image sequence reconstruction and the first-order differential processing is proposed in this work, which is comprised of the following procedures. Firstly, the specimen with four fabricated defects with different sizes is detected by using pulsed infrared thennography. Then, a piecewise fitting based method is proposed to reconstruct the thermal image sequence to compress the data and remove the temporal noise of each pixel in the thermal image. Finally, the first-order differential processing based method is proposed to enhance the contrast. An experimental investigation into the specimen containing de-bond defects between the steel and the heat insulation layer is carried out to validate the effectiveness of the proposed method via the above procedures. The obtained results show that the proposed method can remove the noise, enhance the contrast, and even compress the data reaching at 99.1%, thus improving the detectability of pulsed infrared thermography on metal defects.

关键词： Pulsed infrared thermography metal defects detectability improvement piecewise fitting differential processing

Low-velocity impact response and infrared radiation characteristics of thermoplastic/thermoset composites

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Chinese Journal of Aeronautics 2022年第10期35卷 365-380页

作者： Zhibin ZHAO zhengwei yang Wei ZHANG Dejun LIU Yin LI Jinshu CHEN School of Missile Engineering Rocket Force University of EngineeringXi'an 710038China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049China China Aerodynamics Research and Development Center Mianyang 621000China

The low-velocity impact response and infrared radiation characteristics of composites have rarely been focused on *** study aims to investigate the low-velocity impact response and infrared radiation characteristics of the glass fiber reinforced thermoplastic polypropylene and carbon fiber reinforced thermosetting epoxy resin laminates wildly used in the aircraft *** impact tests were conducted at five energy *** parameters such as impact load,displacement,and absorbed energy were *** damage evolution and damage modes of the laminates were analyzed through active and passive thermography,ultrasonic C-scan,and optical *** results indicate that Thermosets(TS)laminates exhibit better impact resistance,while Thermoplastics(TP)laminates show higher delamination ductility,and the maximum contact force of TP laminates is much smaller than that of the TS laminates under lowvelocity impacts,but the low bending stiffness and low ductility of the TP matrix cause the difference in energy absorption level between the two not *** temperature characteristic changes of passive infrared thermography heat maps could characterize the damage mode of the *** correlation between the heat maps and the impact characteristic curves is explained;the fluctuation of the impact characteristic curves is directly related to the hot spot characteristics changes of the heat *** frequent curve fluctuations correspond to a larger and brighter hot spot on the heat map,which peaks at the maximum impact load after the impact force versus time curve fluctuation cutoff point,the maximum center displacement of the impact force versus displacement curve,and the maximum absorbed energy of the absorbed energy versus time curve.

关键词： Infrared thermography Low-velocity impact Thermoplastic composites Thermoset composites Damage characterization Failure mechanism

Temperature Field in Laser Line Scanning Thermography: Analytical Calculation and Experiment

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Computer Modeling in Engineering & Sciences 2023年第10期137卷 1001-1018页

作者： Yin Li Yuanjia Song zhengwei yang Haijun Jiang Bowen Liu China Aerodynamics Research and Development Center Mianyang621000China Xi’an Research Institute of High Technology Xi’an710025China Nanjing Novelteq Ltd.Nanjing210038China

The temperature field in laser line scanning thermography is investigated comprehensively in this work,including analytical calculation and ***,the principle of laser line scanning thermography is *** this basis,a physical laser line scanning model is ***,based on Fourier transform(FT)and segregation variablemethod(SVM),the heat conduction differential equation in laser line scanning thermography is derived in *** temperature field of the composite-based coatings model with defects is simulated *** results show that the laser line scanning thermography can effectively detect the defects in the *** correctness of the analytical calculation is verified by comparing the surface temperature distribution obtained by analytical calculation and numerical ***,an experiment is carried out and the changeable surface temperature obtained by analytical calculation is compared with the experimental *** shows that the error of maximum temperature obtained by analytical calculation and by experiment is 8%with high accuracy,which proves the correctness of analytical calculation and enriches the theoretical foundation of laser line scanning thermography.

关键词： Temperature field laser line scanning thermography analytical calculation numerical simulation experiment

高质量文本数据驱动的命名实体识别加速镍基单晶高温合金材料知识发现

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金属学报 2024年第10期60卷 1429-1438页

作者：刘悦姚文轩刘大晖丁琳杨正伟刘微于涛施思齐上海大学计算机工程与科学学院上海200444 上海大学材料基因组工程研究院上海200444 钢铁研究总院功能材料研究所北京100081 上海大学材料科学与工程学院上海200444

镍基单晶高温合金构效关系知识常常以非结构化文本的形式存储在海量公开发表的科学文献中。利用命名实体识别(NER)方法从非结构化文本中挖掘关键信息已成为助力新材料研发的重要方式。然而,已有NER方法依赖于大量语料数据支撑且不适用... 详细信息

镍基单晶高温合金构效关系知识常常以非结构化文本的形式存储在海量公开发表的科学文献中。利用命名实体识别(NER)方法从非结构化文本中挖掘关键信息已成为助力新材料研发的重要方式。然而,已有NER方法依赖于大量语料数据支撑且不适用于处理跨领域任务,导致其难以适配镍基单晶高温合金领域。本工作提出基于语义特征融合的深度学习命名实体识别方法(SF-NER),以准确挖掘摘要文本中蕴含的镍基单晶高温合金知识。在领域知识指导下创建材料领域词典以实现远程监督,并建立了高质量镍基单晶高温合金标注语料库(含8类实体类型的19405个实体数据);为准确捕捉特定材料术语,提出了融合编码的词表征策略以捕获关键材料语义特征;构建双向长短期记忆网络-条件随机场(Bi-LSTM-CRF)模型捕捉句子序列中的关键语义信息以实现实体标签的精准预测。实验结果表明,SF-NER能够精准识别镍基单晶高温合金实体类别(评价指标F1值为0.84),有效筛选影响高温合金服役性能的关键因素,并推荐出可用于服役性能构效关系挖掘的高重要度描述符。

关键词：数据质量深度学习命名实体识别镍基单晶高温合金领域知识

A high-resolution,hybrid compact-WENO scheme with minimized dispersion and controllable dissipation

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Science China(Physics,Mechanics & Astronomy) 2014年第5期57卷 971-982页

作者： SUN ZhenSheng HU Yu LUO Lei ZHANG ShiYing yang zhengwei Xi'an Research Institute of High-tech

In this paper, a high-resolution, hybrid compact-WENO scheme is developed based on the minimized dispersion and controllable dissipation reconstruction technique. Firstly, a sufficient condition for a family oftri-diagonal compact schemes to have independent dispersion and dissipation is derived. Then, a specific 4th order compact scheme with low dispersion and adjustable dissipation is constructed and analyzed. Finally, the optimized compact scheme is blended with the WENO scheme to form the hybrid scheme. Moreover, the approximation dispersion relation approach is employed to optimize the spectral properties of the nonlinear scheme to yield the true wave propagation behavior of the finite difference scheme. Several test cases are carried out to verify the high- resolution as well as the robust shock-capturing capabilities of the proposed scheme.

关键词： binaries: high-resolution schemes shock-capturing schemes nonlinear spectral analysis spectral optimization