针对合成孔径雷达(synthetic aperture radar,SAR)稀疏成像中目标反射率易低估、目标结构特征难以精确提取的问题,提出一种基于非凸和相对全变分(relative total variation,RTV)正则化的稀疏SAR成像算法。该算法利用非凸惩罚抑制偏差效...针对合成孔径雷达(synthetic aperture radar,SAR)稀疏成像中目标反射率易低估、目标结构特征难以精确提取的问题,提出一种基于非凸和相对全变分(relative total variation,RTV)正则化的稀疏SAR成像算法。该算法利用非凸惩罚抑制偏差效应、RTV自适应保护图像结构,在交替方向乘子法(alternating direction method of multipliers,ADMM)分布式优化框架下,实现多个正则项的协同优化增强。为更好地提高成像效率和降低内存占用量,利用匹配滤波(match filter,MF)算子构造测量矩阵进行近似观测,并对重建的SAR图像质量进行定量评价。仿真与实测数据处理结果表明,所提方法可有效抑制噪声杂波,在保证空间分辨率的情况下有效提高目标重建精度和辐射分辨率。展开更多
绝缘子室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)涂层的二次喷涂可以有效延长绝缘子的使用寿命,保障电力系统的安全运行。针对喷涂质量的评估问题,提出一种基于卷积神经网络的RTV喷涂缺陷自动检测方法:首先构...绝缘子室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)涂层的二次喷涂可以有效延长绝缘子的使用寿命,保障电力系统的安全运行。针对喷涂质量的评估问题,提出一种基于卷积神经网络的RTV喷涂缺陷自动检测方法:首先构建绝缘子RTV喷涂区域提取网络模型,对绝缘子RTV喷涂区域进行精确分割;然后构建绝缘子RTV喷涂缺陷检测网络模型,对5种喷涂缺陷进行语义分割。实验结果证明,所构建的喷涂缺陷检测网络模型在评价指标上优于主流的语义分割网络,具有良好的性能,能够满足应用需求。展开更多
The viscosity-time curve of a single-component polyurethane(PU)was examined to determine the mixing and compacting temperatures of its mixture and investigate the curing and mechanical properties of single-component P...The viscosity-time curve of a single-component polyurethane(PU)was examined to determine the mixing and compacting temperatures of its mixture and investigate the curing and mechanical properties of single-component PU porous elastic mixture(PPEM).The curing properties of the single-component PU and PPEM were studied with Fourier transform infrared spectroscopy(FTIR)and Marshall test.The mechanical properties of PPEM were explored via the following tests:rutting test,3-point bending test,soaked Marshall stability test,freeze-thaw splitting test,and Cantabro test.The effects of a water bath on the stability of aggregate-PU/asphalt mortar-aggregate systems were evaluated through a pull-out test and a shear test.The results show that the recommended mixing temperatures of toluene diisocyanate and methylene diphenyl diisocyanate range from 75 to 80℃and from 64 to 68℃,respectively.Room temperature(25℃)can be adopted as the compacting temperature of PPEM.PPEM can be fully cured in 4 d.Nevertheless,the water sprinkle method can obviously shorten the full curing time of PPEM.PPEM exhibites good resistance to rutting,brittle cracking,and raveling.The adhesive and shear strength of aggregate-PU/asphalt mortar-aggregate systems are negatively related to water bath duration.展开更多
A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167...A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.展开更多
为分析高湿气候下室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)防污闪涂料的运行特性,对广东地区使用多年的RTV绝缘子进行了试验研究,包括外观状态、附着力、憎水性、污秽度等以及污秽闪络试验,并与山西地区RTV绝...为分析高湿气候下室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)防污闪涂料的运行特性,对广东地区使用多年的RTV绝缘子进行了试验研究,包括外观状态、附着力、憎水性、污秽度等以及污秽闪络试验,并与山西地区RTV绝缘子的运行特性进行对比分析,在此基础上,提出了高湿气候下RTV涂料运行特性的特殊劣化特征及相关原因,并通过实验室模拟试验研究了这种劣化特征对绝缘子耐污闪性能的影响。结果表明,高湿气候下,广东RTV绝缘子的外观状态、附着力、憎水性都劣化得更为严重,悬垂串绝缘子与耐张串绝缘子表面的RTV涂层劣化特征不同,高湿多雨环境对RTV涂层的粘结性能有影响。试验结果及结论为高湿气候地区RTV涂料的使用和推广提供一定的试验依据。展开更多
文摘针对合成孔径雷达(synthetic aperture radar,SAR)稀疏成像中目标反射率易低估、目标结构特征难以精确提取的问题,提出一种基于非凸和相对全变分(relative total variation,RTV)正则化的稀疏SAR成像算法。该算法利用非凸惩罚抑制偏差效应、RTV自适应保护图像结构,在交替方向乘子法(alternating direction method of multipliers,ADMM)分布式优化框架下,实现多个正则项的协同优化增强。为更好地提高成像效率和降低内存占用量,利用匹配滤波(match filter,MF)算子构造测量矩阵进行近似观测,并对重建的SAR图像质量进行定量评价。仿真与实测数据处理结果表明,所提方法可有效抑制噪声杂波,在保证空间分辨率的情况下有效提高目标重建精度和辐射分辨率。
文摘绝缘子室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)涂层的二次喷涂可以有效延长绝缘子的使用寿命,保障电力系统的安全运行。针对喷涂质量的评估问题,提出一种基于卷积神经网络的RTV喷涂缺陷自动检测方法:首先构建绝缘子RTV喷涂区域提取网络模型,对绝缘子RTV喷涂区域进行精确分割;然后构建绝缘子RTV喷涂缺陷检测网络模型,对5种喷涂缺陷进行语义分割。实验结果证明,所构建的喷涂缺陷检测网络模型在评价指标上优于主流的语义分割网络,具有良好的性能,能够满足应用需求。
基金The Fundamental Research Funds for the Central Research Institute (No. 2020-9054)。
文摘The viscosity-time curve of a single-component polyurethane(PU)was examined to determine the mixing and compacting temperatures of its mixture and investigate the curing and mechanical properties of single-component PU porous elastic mixture(PPEM).The curing properties of the single-component PU and PPEM were studied with Fourier transform infrared spectroscopy(FTIR)and Marshall test.The mechanical properties of PPEM were explored via the following tests:rutting test,3-point bending test,soaked Marshall stability test,freeze-thaw splitting test,and Cantabro test.The effects of a water bath on the stability of aggregate-PU/asphalt mortar-aggregate systems were evaluated through a pull-out test and a shear test.The results show that the recommended mixing temperatures of toluene diisocyanate and methylene diphenyl diisocyanate range from 75 to 80℃and from 64 to 68℃,respectively.Room temperature(25℃)can be adopted as the compacting temperature of PPEM.PPEM can be fully cured in 4 d.Nevertheless,the water sprinkle method can obviously shorten the full curing time of PPEM.PPEM exhibites good resistance to rutting,brittle cracking,and raveling.The adhesive and shear strength of aggregate-PU/asphalt mortar-aggregate systems are negatively related to water bath duration.
基金supported by the National Natural Science Foundation of China(No.20172034)Foundation for Univemity Key Teacher by Ministry of Educationthe grant for the State Key Program of China.
文摘A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.
文摘为分析高湿气候下室温硫化硅橡胶(room temperature vulcanized silicone rubber,RTV)防污闪涂料的运行特性,对广东地区使用多年的RTV绝缘子进行了试验研究,包括外观状态、附着力、憎水性、污秽度等以及污秽闪络试验,并与山西地区RTV绝缘子的运行特性进行对比分析,在此基础上,提出了高湿气候下RTV涂料运行特性的特殊劣化特征及相关原因,并通过实验室模拟试验研究了这种劣化特征对绝缘子耐污闪性能的影响。结果表明,高湿气候下,广东RTV绝缘子的外观状态、附着力、憎水性都劣化得更为严重,悬垂串绝缘子与耐张串绝缘子表面的RTV涂层劣化特征不同,高湿多雨环境对RTV涂层的粘结性能有影响。试验结果及结论为高湿气候地区RTV涂料的使用和推广提供一定的试验依据。
