基于闭集算法的声纹识别模型由几类故障样本与正常样本训练得到,同时假设后续输入样本同属于这几个确定的类别。在应用中,强环境噪声等陌生类别可能导致大量误报。为在室外等多噪声环境下降低误报率,同时保持故障样本召回率,提出了一种...基于闭集算法的声纹识别模型由几类故障样本与正常样本训练得到,同时假设后续输入样本同属于这几个确定的类别。在应用中,强环境噪声等陌生类别可能导致大量误报。为在室外等多噪声环境下降低误报率,同时保持故障样本召回率,提出了一种基于新奇检测的两级声纹识别算法。以断路器储能电机为实验对象,对1种正常工况和3种异常工况的声音信号进行加窗、分帧等预处理,随后提取梅尔频率倒谱系数(Mel frequency cestrum coefficient,MFCC)特征向量,最后使用单类支持向量机(one-class support vector machine,one-class SVM)作为第1级新奇检测算法分离陌生类,再使用C参数支持向量机(c-support vector machine,C-SVM)作为第2级算法进行识别。实验结果表明,与现有的单级声纹识别方法相比,所提出的方法可以有效检出陌生类,在信噪比高于20dB时故障样本召回率下降小于0.33%,在信噪比低于20dB时误报率下降超过63.47%。展开更多
为了降低声纹识别算法在低信噪比环境下的误报率,提出了一种基于快速增量式支持向量数据描述(fast incremental support vector data description,FISVDD)以及门控循环单元(gate recurrent unit,GRU)的变压器机械故障声纹识别方法。以...为了降低声纹识别算法在低信噪比环境下的误报率,提出了一种基于快速增量式支持向量数据描述(fast incremental support vector data description,FISVDD)以及门控循环单元(gate recurrent unit,GRU)的变压器机械故障声纹识别方法。以变压器为实验对象,分别获取变压器在正常工况、铁芯松动、线圈松动3种状态下的声音信号,并使用Mel频率倒谱系数进行特征提取。FISVDD作为第1级算法分离陌生类,同时通过增量学习的方式学习新样本。GRU作为第2级分类算法,对通过第1级算法的样本进行识别。实验结果表明:与传统闭集识别算法相比,FISVDD需要的训练时间更少;相较于传统的机器学习算法,GRU在变压器音频识别任务中具有更高的识别准确率和抗噪识别能力;所提方法相较于1级算法更加有效,在识别信噪比高于10 dB的样本时召回率下降不超过1%,在识别信噪比不超过0 dB的样本时误报率不超过10%。展开更多
One-pot synthesis of magnetic nanogels via photochemical method is reported in this paper. Poly(2-hydroxyethyl methacrylate)(PHEMA) magnetic nanogels are synthesized by in-situ polymeriza-tion of 2-hydroxyethyl methac...One-pot synthesis of magnetic nanogels via photochemical method is reported in this paper. Poly(2-hydroxyethyl methacrylate)(PHEMA) magnetic nanogels are synthesized by in-situ polymeriza-tion of 2-hydroxyethyl methacrylate(HEMA) and N,N'-methylene-bis-(acrylamide)(MBA) in Fe3O4 aqueous suspension under UV irradiation. The structure and compositions of magnetic nanogels are characterized by FTIR,TGA,SEM,TEM and PCS. TGA measurement indicates that magnetic nanogels contain 90% magnetite. Both naked Fe3O4 and magnetic nanogels are superparamagnatic at room temperature according to magnetization curves. The swollen capability of the hydrogel shell is proved by contrasting the particles sizes obtained by SEM,TEM and PCS. Particle diameters can be manipu-lated by changing monomer concentration and irradiation time. A mechanism of the coating process is proposed.展开更多
One-pot synthesis of magnetic nanogels with excellent biocompatibility via the photochemical method is reported in this paper.Poly(PEGMA) modified superparamagnetic nanogels(poly(PEGMA) magnetic nanogels) were synthes...One-pot synthesis of magnetic nanogels with excellent biocompatibility via the photochemical method is reported in this paper.Poly(PEGMA) modified superparamagnetic nanogels(poly(PEGMA) magnetic nanogels) were synthesized by in-situ polymerization using poly(ethylene glycol) methacrylate(PEGMA) as the monomer and N,N'-methylene-bis-(acrylamide)(MBA) as the cross-linking agent in magnetite aqueous suspension under UV irradiation.The surface functional groups and components of magnetic nanogels were analyzed by Fourier transform infrared spectroscopy(FTIR) and a thermogra-vimetric analyzer(TGA).The results indicated that the poly(PEGMA) magnetic nanogels were synthe-sized successfully by coating poly(PEGMA) on the Fe3O4 nanoparticles under UV irradiation,and the Fe3O4 nanoparticles content in this nanogels was above 50 wt%.The morphology,size,zeta-potential and magnetic property were also characterized.The magnetic nanogels had a nearly spherical shape and core-shell structure,the average size in aqueous system measured by photon correlation spec-troscopy(PCS) was 68.4 nm,which was much bigger than that in the dry state,the nanogels behaved superparamagnetically with saturated magnetization of 58.6 emu/g,and the zeta-potential was-16.3-_17.3 mV at physiological pH(6.8-7.4) which could help to maintain stability in blood.The preliminary application as drug carrier was made and the doxorubicin-loaded magnetic nanogels had an excellent property in slow-release.The experiment indicated that the magnetic nanogel was an ideal candidate carrier in target drug delivery systems and other biomedical application.展开更多
Intelligent well technology is an oil and gas well optimization completion technology integrated with underground real-time monitoring,data analysis decision-making and remote control of downhole tools.It's of gre...Intelligent well technology is an oil and gas well optimization completion technology integrated with underground real-time monitoring,data analysis decision-making and remote control of downhole tools.It's of great significance to the transformation and innovation of China's oil and gas development projects.The author of this paper expounds the definition,principle,composition and characteristics of intelligent well technology,and introduces the development status quo of intelligent well technology abroad,including mature intelligent well system,key technology research of intelligent well and its application technology.After the introduction to the related technology research of intelligent well in China,the author puts forward some opinions on the development of our own complete intelligent well system.展开更多
文摘基于闭集算法的声纹识别模型由几类故障样本与正常样本训练得到,同时假设后续输入样本同属于这几个确定的类别。在应用中,强环境噪声等陌生类别可能导致大量误报。为在室外等多噪声环境下降低误报率,同时保持故障样本召回率,提出了一种基于新奇检测的两级声纹识别算法。以断路器储能电机为实验对象,对1种正常工况和3种异常工况的声音信号进行加窗、分帧等预处理,随后提取梅尔频率倒谱系数(Mel frequency cestrum coefficient,MFCC)特征向量,最后使用单类支持向量机(one-class support vector machine,one-class SVM)作为第1级新奇检测算法分离陌生类,再使用C参数支持向量机(c-support vector machine,C-SVM)作为第2级算法进行识别。实验结果表明,与现有的单级声纹识别方法相比,所提出的方法可以有效检出陌生类,在信噪比高于20dB时故障样本召回率下降小于0.33%,在信噪比低于20dB时误报率下降超过63.47%。
文摘为了降低声纹识别算法在低信噪比环境下的误报率,提出了一种基于快速增量式支持向量数据描述(fast incremental support vector data description,FISVDD)以及门控循环单元(gate recurrent unit,GRU)的变压器机械故障声纹识别方法。以变压器为实验对象,分别获取变压器在正常工况、铁芯松动、线圈松动3种状态下的声音信号,并使用Mel频率倒谱系数进行特征提取。FISVDD作为第1级算法分离陌生类,同时通过增量学习的方式学习新样本。GRU作为第2级分类算法,对通过第1级算法的样本进行识别。实验结果表明:与传统闭集识别算法相比,FISVDD需要的训练时间更少;相较于传统的机器学习算法,GRU在变压器音频识别任务中具有更高的识别准确率和抗噪识别能力;所提方法相较于1级算法更加有效,在识别信噪比高于10 dB的样本时召回率下降不超过1%,在识别信噪比不超过0 dB的样本时误报率不超过10%。
基金Supported by the Shanghai Municipal Commission for Special Project of Nanometer Science and Technology (Grant No. 0452nm068)
文摘One-pot synthesis of magnetic nanogels via photochemical method is reported in this paper. Poly(2-hydroxyethyl methacrylate)(PHEMA) magnetic nanogels are synthesized by in-situ polymeriza-tion of 2-hydroxyethyl methacrylate(HEMA) and N,N'-methylene-bis-(acrylamide)(MBA) in Fe3O4 aqueous suspension under UV irradiation. The structure and compositions of magnetic nanogels are characterized by FTIR,TGA,SEM,TEM and PCS. TGA measurement indicates that magnetic nanogels contain 90% magnetite. Both naked Fe3O4 and magnetic nanogels are superparamagnatic at room temperature according to magnetization curves. The swollen capability of the hydrogel shell is proved by contrasting the particles sizes obtained by SEM,TEM and PCS. Particle diameters can be manipu-lated by changing monomer concentration and irradiation time. A mechanism of the coating process is proposed.
基金Supported by the Natural Science Foundation of Shandong Province (Grant No. Q2006F01)Scientific and Technological Project of Shandong Province (Grant No. 2007GG3WZ02066)+1 种基金Scientific and Technological Project of Department of Education, Shandong (Grant No. J07WC01)supported by the Key Laboratory of Bio-physics of Shandong Province
文摘One-pot synthesis of magnetic nanogels with excellent biocompatibility via the photochemical method is reported in this paper.Poly(PEGMA) modified superparamagnetic nanogels(poly(PEGMA) magnetic nanogels) were synthesized by in-situ polymerization using poly(ethylene glycol) methacrylate(PEGMA) as the monomer and N,N'-methylene-bis-(acrylamide)(MBA) as the cross-linking agent in magnetite aqueous suspension under UV irradiation.The surface functional groups and components of magnetic nanogels were analyzed by Fourier transform infrared spectroscopy(FTIR) and a thermogra-vimetric analyzer(TGA).The results indicated that the poly(PEGMA) magnetic nanogels were synthe-sized successfully by coating poly(PEGMA) on the Fe3O4 nanoparticles under UV irradiation,and the Fe3O4 nanoparticles content in this nanogels was above 50 wt%.The morphology,size,zeta-potential and magnetic property were also characterized.The magnetic nanogels had a nearly spherical shape and core-shell structure,the average size in aqueous system measured by photon correlation spec-troscopy(PCS) was 68.4 nm,which was much bigger than that in the dry state,the nanogels behaved superparamagnetically with saturated magnetization of 58.6 emu/g,and the zeta-potential was-16.3-_17.3 mV at physiological pH(6.8-7.4) which could help to maintain stability in blood.The preliminary application as drug carrier was made and the doxorubicin-loaded magnetic nanogels had an excellent property in slow-release.The experiment indicated that the magnetic nanogel was an ideal candidate carrier in target drug delivery systems and other biomedical application.
基金This research was supported by PetroChina Co Ltd.Science and Technology Major Project(2016E-0612)Ministry of Education(Southwest Petroleum University),Scientific Research Starting Project of SWPU(No.2017QHZ012)+1 种基金Sichuan science and technology program(2019YFG0305,2018GZ0429,2018CC0098)National Research Council of Science and Technology Major Project(2017ZX05023-002).
文摘Intelligent well technology is an oil and gas well optimization completion technology integrated with underground real-time monitoring,data analysis decision-making and remote control of downhole tools.It's of great significance to the transformation and innovation of China's oil and gas development projects.The author of this paper expounds the definition,principle,composition and characteristics of intelligent well technology,and introduces the development status quo of intelligent well technology abroad,including mature intelligent well system,key technology research of intelligent well and its application technology.After the introduction to the related technology research of intelligent well in China,the author puts forward some opinions on the development of our own complete intelligent well system.
