The present work investigates the potential applications of nitrogen oxides(NO_(x)),particularly nitric oxide(NO)and nitrogen dioxide(NO_(2)),generated through discharge plasma in diverse sectors such as medicine,nitr...The present work investigates the potential applications of nitrogen oxides(NO_(x)),particularly nitric oxide(NO)and nitrogen dioxide(NO_(2)),generated through discharge plasma in diverse sectors such as medicine,nitrogen fixation,energy,and environmental protection.In this study,a rotating sliding arc discharge reactor was initially employed to produce high concentrations of gaseous NO_(x),followed by the utilization of a molybdenum wire redox reactor for NO_(2)-to-NO conversion.The outcomes reveal that the discharge states and generations of NO_(x) are affected by varying parameters,including the applied energies,frequencies and airflow states(1.3-2.6 m/s are the laminar flow,2.6-5.2 m/s are the transition state,5.2-6.5 m/s are the turbulent flow),and the concentrations of NO_(x) within the arc discharge are higher than that in the spark discharge.Moreover,the concentrations of NO,NO_(2) and NO_(x) gradually increased,and the concentration ratios of NO/NO_(2) and NO_(x)/NO_(2) decreased with increasing the applied energy for one cycle from 14.8 mJ to 24.3 mJ.Meanwhile,the concentrations of NO,NO_(2) and NO_(x) gradually decreased,and the concentration ratios of NO/NO_(2) and NO_(x)/NO_(2) first decreased and then increased with increasing the applied frequencies from 5.0 kHz to 9.0 kHz.Further,the concentrations of NO,NO_(2) and NO_(x) gradually decreased,and the concentration ratios of NO/NO_(2) and NO_(x)/NO_(2) first increased and then decreased with increasing the air flow speeds from 1.3 m/s to 6.5 m/s.Lastly,the concentrations of NO increased and NO_(2) decreased with increasing temperature from 25℃ to 400℃ using molybdenum converted.These findings provide experimental support for the application of plasma in the fields of medicine,nitrogen fixation,energy and environmental protection.展开更多
A typical 321 stainless steel/aluminum composite coating (321/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode. The tr...A typical 321 stainless steel/aluminum composite coating (321/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode. The traditional 321 stainless steel coating was also prepared for comparison. Tribological properties of the coatings were evaluated with the ring-block wear tester under different conditions. The structure and worn surface of the coatings were analyzed by scanning electron microscopy(SEM), X-ray diffractometry(XRD) and energy dispersion spectroscopy(EDS). The results show that, except for aluminum phase addition in the 321/Al coating, no other phases are created compared with the 321 coating. However, due to the addition of aluminum, the 321/Al coating forms a type of "ductile/hard phases inter-deposited" structure and performs quite different tribological behavior. Under the dry sliding condition, the anti-wear property of 321/Al coating is about 42% lower than that of 321 coating. But under the oil lubricated conditions with or without 32 h oil-dipping pretreatment, the anti-wear property of 321/Al coating is about 9% and 5% higher than that of 321 coating, respectively. The anti-wear mechanism of the composite coating is mainly relevant to the decrease of oxide impurities and the strengthening action resulted from the "ductile/hard phases inter-deposited" coating structure.展开更多
当三相异步电动机发生机械振动时,主回路中接触不良的电气接触点在振动作用下会产生串联型故障电弧,进而影响电路安全甚至引发电气火灾。而振动条件会加剧了故障电弧信号的复杂性,因此本文以回路电流信号为研究对象,提出了一种振动条件...当三相异步电动机发生机械振动时,主回路中接触不良的电气接触点在振动作用下会产生串联型故障电弧,进而影响电路安全甚至引发电气火灾。而振动条件会加剧了故障电弧信号的复杂性,因此本文以回路电流信号为研究对象,提出了一种振动条件下的高实时性串联型故障电弧检测方法。首先通过构建滑动记忆矩阵对实验电流数据进行动态保存,其次通过正交方向改进局部三值化模式(orthogonality direction local ternary pattern,OD-LTP)提取滑动记忆矩阵的纹理特征,最终将统计的OD-LTP图像的灰度分布直方图幅值作为特征向量,通过基于沙猫群优化(sand cat swarm optimization,SCSO)的支持向量机(support vector machine,SVM)建立振动串联型故障电弧检测模型。本文通过对比不同矩阵参数,得到最佳的滑动记忆矩阵尺寸,最终所提方法对故障电弧识别的准确率达到99.2%。通过对不同工况、不同特征提取方法对比分析,表明本文提出方法不仅适用于不同工况运行的工业电机变频器系统,其相对于其他特征提取方法也具有较高的实时性。展开更多
基金partially supported by National Natural Science Foundation of China(No.52477141)the Natural Science Foundation of the Jiangsu Province(No.BK20191162)+2 种基金Fundamental Research Funds for the Central Universities(No.B210203006)the Research Fund of Innovation and Entrepreneurship Education Reform for Chinese Universities(No.16CCJG01Z004)Changzhou Science and Technology Program(No.CJ20190046).
文摘The present work investigates the potential applications of nitrogen oxides(NO_(x)),particularly nitric oxide(NO)and nitrogen dioxide(NO_(2)),generated through discharge plasma in diverse sectors such as medicine,nitrogen fixation,energy,and environmental protection.In this study,a rotating sliding arc discharge reactor was initially employed to produce high concentrations of gaseous NO_(x),followed by the utilization of a molybdenum wire redox reactor for NO_(2)-to-NO conversion.The outcomes reveal that the discharge states and generations of NO_(x) are affected by varying parameters,including the applied energies,frequencies and airflow states(1.3-2.6 m/s are the laminar flow,2.6-5.2 m/s are the transition state,5.2-6.5 m/s are the turbulent flow),and the concentrations of NO_(x) within the arc discharge are higher than that in the spark discharge.Moreover,the concentrations of NO,NO_(2) and NO_(x) gradually increased,and the concentration ratios of NO/NO_(2) and NO_(x)/NO_(2) decreased with increasing the applied energy for one cycle from 14.8 mJ to 24.3 mJ.Meanwhile,the concentrations of NO,NO_(2) and NO_(x) gradually decreased,and the concentration ratios of NO/NO_(2) and NO_(x)/NO_(2) first decreased and then increased with increasing the applied frequencies from 5.0 kHz to 9.0 kHz.Further,the concentrations of NO,NO_(2) and NO_(x) gradually decreased,and the concentration ratios of NO/NO_(2) and NO_(x)/NO_(2) first increased and then decreased with increasing the air flow speeds from 1.3 m/s to 6.5 m/s.Lastly,the concentrations of NO increased and NO_(2) decreased with increasing temperature from 25℃ to 400℃ using molybdenum converted.These findings provide experimental support for the application of plasma in the fields of medicine,nitrogen fixation,energy and environmental protection.
基金Project(50735006) supported by the National Natural Science Foundation of ChinaProject(2006BAF02A19) supported by the National Science and Technology Support Program of China
文摘A typical 321 stainless steel/aluminum composite coating (321/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode. The traditional 321 stainless steel coating was also prepared for comparison. Tribological properties of the coatings were evaluated with the ring-block wear tester under different conditions. The structure and worn surface of the coatings were analyzed by scanning electron microscopy(SEM), X-ray diffractometry(XRD) and energy dispersion spectroscopy(EDS). The results show that, except for aluminum phase addition in the 321/Al coating, no other phases are created compared with the 321 coating. However, due to the addition of aluminum, the 321/Al coating forms a type of "ductile/hard phases inter-deposited" structure and performs quite different tribological behavior. Under the dry sliding condition, the anti-wear property of 321/Al coating is about 42% lower than that of 321 coating. But under the oil lubricated conditions with or without 32 h oil-dipping pretreatment, the anti-wear property of 321/Al coating is about 9% and 5% higher than that of 321 coating, respectively. The anti-wear mechanism of the composite coating is mainly relevant to the decrease of oxide impurities and the strengthening action resulted from the "ductile/hard phases inter-deposited" coating structure.
文摘当三相异步电动机发生机械振动时,主回路中接触不良的电气接触点在振动作用下会产生串联型故障电弧,进而影响电路安全甚至引发电气火灾。而振动条件会加剧了故障电弧信号的复杂性,因此本文以回路电流信号为研究对象,提出了一种振动条件下的高实时性串联型故障电弧检测方法。首先通过构建滑动记忆矩阵对实验电流数据进行动态保存,其次通过正交方向改进局部三值化模式(orthogonality direction local ternary pattern,OD-LTP)提取滑动记忆矩阵的纹理特征,最终将统计的OD-LTP图像的灰度分布直方图幅值作为特征向量,通过基于沙猫群优化(sand cat swarm optimization,SCSO)的支持向量机(support vector machine,SVM)建立振动串联型故障电弧检测模型。本文通过对比不同矩阵参数,得到最佳的滑动记忆矩阵尺寸,最终所提方法对故障电弧识别的准确率达到99.2%。通过对不同工况、不同特征提取方法对比分析,表明本文提出方法不仅适用于不同工况运行的工业电机变频器系统,其相对于其他特征提取方法也具有较高的实时性。
