As a kind of brand-new technology, radio frequency identification management, data control and acquisition. This paper introduced food safety system construction, analyzed the advantages and problems in dairy modem su...As a kind of brand-new technology, radio frequency identification management, data control and acquisition. This paper introduced food safety system construction, analyzed the advantages and problems in dairy modem suggestions for solution according to the practical situation. （RFID） plays an important role in dairy information tracing and culture function extension of managing breeding technology, and finally put forward some展开更多
In order to improve the surface hydrophobicity, silicone rubber （SIR） samples were exposed to CF4 radio frequency （RF） capacitively coupled plasma （CCP）. Attenuated total reflection Fourier transform infrared （...In order to improve the surface hydrophobicity, silicone rubber （SIR） samples were exposed to CF4 radio frequency （RF） capacitively coupled plasma （CCP）. Attenuated total reflection Fourier transform infrared （ATR-FTIR） spectrum and X-ray photoelectron spectroscopy （XPS） were used to observe the variation of the functional groups of the modified SIR. Static contact angle （SCA） was employed to estimate the change of hydrophobicity of the modified SIR. The surface energy of SIR is reduced largely from 27.37 mJ/m^2 of original SIR sample to 2.94 mJ/m^2 of SIR sample treated by CF4 CCP modification at RF power of 200 W for a treatment time of 5 rnin. According to the XPS, ATR-FTIR and surface energy analysis, it is suggested that the improvement of hydrophobicity on the modified SIR surface is mainly ascribed to the decrease of surface energy, which is caused by the cooperation of the fluosilicic structure of Si--F or Si--F2 and the fluoric groups of C--CFn induced by the methyl replacement reaction and residual methyl groups of SIR surface.展开更多
Not confined to a certain point,such as waveform,this paper systematically studies the low-intercept radio frequency(RF)stealth design of synthetic aperture radar(SAR)from the system level.The study is carried out fro...Not confined to a certain point,such as waveform,this paper systematically studies the low-intercept radio frequency(RF)stealth design of synthetic aperture radar(SAR)from the system level.The study is carried out from two levels.In the first level,the maximum low-intercept range equation of the conventional SAR system is deduced firstly,and then the maximum low-intercept range equation of the multiple-input multiple-output SAR system is deduced.In the second level,the waveform design and imaging method of the low-intercept RF SAR system are given and verified by simulation.Finally,the main technical characteristics of the lowintercept RF stealth SAR system are given to guide the design of low-intercept RF stealth SAR system.展开更多
目的确保物品包装上的超高频射频识别(Radio Frequency Identification,RFID)标签一致性关键指标符合相关标准,解决现有文献对一致性关键指标阐述不全面的问题,基于ISO/IEC 18000-63和ISO/IEC 18047-63对一致性关键指标的测试方法展开...目的确保物品包装上的超高频射频识别(Radio Frequency Identification,RFID)标签一致性关键指标符合相关标准,解决现有文献对一致性关键指标阐述不全面的问题,基于ISO/IEC 18000-63和ISO/IEC 18047-63对一致性关键指标的测试方法展开研究。方法在对现有一致性测试方法进行研究阐述的基础上,改进了状态跳转和截断响应的测试方法,提升了测试准确性;设计了一种时隙计数器测试方法,该方法通过改变Q值和重复发送QueryRep命令,验证时隙计数器在非0到0的变化过程中,标签有且仅有一次响应,从而避免出现多个标签同时应答的现象。结果应用改进及新设计的测试方法对指定标签进行测试,结果符合标准。结论较为全面地实现了对RFID标签的客观验证和有效评估,对提升RFID标签在实际应用中的可靠性具有重要意义。展开更多
研究设计并实现了一种基于U型谐振单元的无芯片射频识别(radio frequency identification,RFID)技术湿度传感器,该传感器结合Vivaldi宽频段天线,构建了一套无线无源的湿度传感系统,可实现对环境湿度的实时监测。无芯片RFID湿度传感器由8...研究设计并实现了一种基于U型谐振单元的无芯片射频识别(radio frequency identification,RFID)技术湿度传感器,该传感器结合Vivaldi宽频段天线,构建了一套无线无源的湿度传感系统,可实现对环境湿度的实时监测。无芯片RFID湿度传感器由8个U型谐振单元和1条与之耦合的微带线构成。在该设计中,两侧对称的谐振单元用于校准环境温度对湿度传感器的影响,其中1个单元由聚乙烯醇(polyvinyl alcohol,PVA)湿敏材料覆盖;中间6个U型单元用于RFID湿度传感器的ID信息编码。此外,本工作采用矩形环开槽技术优化了宽频带Vivaldi天线,并结合传感器实现了无线无源湿度传感。有线实验数据显示,在57%RH~71%RH的相对湿度范围内,产生了118 MHz的频率偏移,平均灵敏度为8.4 MHz/%RH。无线实验结果显示,在49%RH~70%RH的相对湿度范围内,产生了103 MHz的频率偏移,平均灵敏度为4.9 MHz/%RH。实验结果表明该无线无源湿度传感装置具有较高的检测灵敏度,可为无线无源湿度检测提供重要的解决方案。展开更多
The interrupted-sampling repeater jamming(ISRJ)can cause false targets to the radio-frequency proximity sensors(RFPSs),resulting in a serious decline in the target detection capability of the RFPS.This article propose...The interrupted-sampling repeater jamming(ISRJ)can cause false targets to the radio-frequency proximity sensors(RFPSs),resulting in a serious decline in the target detection capability of the RFPS.This article proposes a recognition method for RFPSs to identify the false targets caused by ISRJ.The proposed method is realized by assigning a unique identity(ID)to each RFPS,and each ID is a periodically and chaotically encrypted in every pulse period.The processing technique of the received signal is divided into ranging and ID decryption.In the ranging part,a high-resolution range profile(HRRP)can be obtained by performing pulse compression with the binary chaotic sequences.To suppress the noise,the singular value decomposition(SVD)is applied in the preprocessing.Regarding ID decryption,targets and ISRJ can be recognized through the encryption and decryption processes,which are controlled by random keys.An adaptability analysis conducted in terms of the peak-to-side lobe ratio(PSLR)and bit error rate(BER)indicates that the proposed method performs well within a 70-k Hz Doppler shift.A simulation and experimental results show that the proposed method achieves extremely stable target and ISRJ recognition accuracies at different signal-to-noise ratios(SNRs)and jamming-to-signal ratios(JSRs).展开更多
绝缘油是电抗器内部重要的绝缘介质,击穿电压是评估其绝缘特性的关键指标,与绝缘油的品质状态密切相关。本文共选取155组电抗器绝缘油进行实验,分别进行击穿电压的测定和多频超声信号在油样中传播衰减后信号的采集,分析多频超声声学参...绝缘油是电抗器内部重要的绝缘介质,击穿电压是评估其绝缘特性的关键指标,与绝缘油的品质状态密切相关。本文共选取155组电抗器绝缘油进行实验,分别进行击穿电压的测定和多频超声信号在油样中传播衰减后信号的采集,分析多频超声声学参数和击穿电压之间的幅频响应、相频响应之间的关系,并基于多频超声检测技术提出结合灰狼优化算法(grey wolf optimizer,GWO)优化随机森林算法(random forest algorithm,RF)的击穿电压预测方法。结果表明:GWO-RF绝缘油击穿电压预测模型的预测值与实际值的平均相对误差为4.04%,预测准确率达到95.96%,相较于优化前的RF绝缘油击穿电压预测模型准确率提升了20.25%。结合多频超声检测技术和GWO-RF建立的并联电抗器绝缘油击穿电压预测模型,对击穿电压的预测具有可行性。展开更多
基金Supported by the Project of the National "948" (2006-Z12)
文摘As a kind of brand-new technology, radio frequency identification management, data control and acquisition. This paper introduced food safety system construction, analyzed the advantages and problems in dairy modem suggestions for solution according to the practical situation. （RFID） plays an important role in dairy information tracing and culture function extension of managing breeding technology, and finally put forward some
基金Project(05JT1034) supported by the Plan of Science and Technology Bureau of Hunan Province,China
文摘In order to improve the surface hydrophobicity, silicone rubber （SIR） samples were exposed to CF4 radio frequency （RF） capacitively coupled plasma （CCP）. Attenuated total reflection Fourier transform infrared （ATR-FTIR） spectrum and X-ray photoelectron spectroscopy （XPS） were used to observe the variation of the functional groups of the modified SIR. Static contact angle （SCA） was employed to estimate the change of hydrophobicity of the modified SIR. The surface energy of SIR is reduced largely from 27.37 mJ/m^2 of original SIR sample to 2.94 mJ/m^2 of SIR sample treated by CF4 CCP modification at RF power of 200 W for a treatment time of 5 rnin. According to the XPS, ATR-FTIR and surface energy analysis, it is suggested that the improvement of hydrophobicity on the modified SIR surface is mainly ascribed to the decrease of surface energy, which is caused by the cooperation of the fluosilicic structure of Si--F or Si--F2 and the fluoric groups of C--CFn induced by the methyl replacement reaction and residual methyl groups of SIR surface.
基金supported by the National Key R&D Program of China(2017YFC1405600)the Fundamental Research Funds for the Central Universities(JB180213)
文摘Not confined to a certain point,such as waveform,this paper systematically studies the low-intercept radio frequency(RF)stealth design of synthetic aperture radar(SAR)from the system level.The study is carried out from two levels.In the first level,the maximum low-intercept range equation of the conventional SAR system is deduced firstly,and then the maximum low-intercept range equation of the multiple-input multiple-output SAR system is deduced.In the second level,the waveform design and imaging method of the low-intercept RF SAR system are given and verified by simulation.Finally,the main technical characteristics of the lowintercept RF stealth SAR system are given to guide the design of low-intercept RF stealth SAR system.
文摘目的确保物品包装上的超高频射频识别(Radio Frequency Identification,RFID)标签一致性关键指标符合相关标准,解决现有文献对一致性关键指标阐述不全面的问题,基于ISO/IEC 18000-63和ISO/IEC 18047-63对一致性关键指标的测试方法展开研究。方法在对现有一致性测试方法进行研究阐述的基础上,改进了状态跳转和截断响应的测试方法,提升了测试准确性;设计了一种时隙计数器测试方法,该方法通过改变Q值和重复发送QueryRep命令,验证时隙计数器在非0到0的变化过程中,标签有且仅有一次响应,从而避免出现多个标签同时应答的现象。结果应用改进及新设计的测试方法对指定标签进行测试,结果符合标准。结论较为全面地实现了对RFID标签的客观验证和有效评估,对提升RFID标签在实际应用中的可靠性具有重要意义。
基金supported by the National Natural Science Foundation of China(Grant No.61973037)and(Grant No.61871414)Postdoctoral Fundation of China(Grant No.2022M720419)。
文摘The interrupted-sampling repeater jamming(ISRJ)can cause false targets to the radio-frequency proximity sensors(RFPSs),resulting in a serious decline in the target detection capability of the RFPS.This article proposes a recognition method for RFPSs to identify the false targets caused by ISRJ.The proposed method is realized by assigning a unique identity(ID)to each RFPS,and each ID is a periodically and chaotically encrypted in every pulse period.The processing technique of the received signal is divided into ranging and ID decryption.In the ranging part,a high-resolution range profile(HRRP)can be obtained by performing pulse compression with the binary chaotic sequences.To suppress the noise,the singular value decomposition(SVD)is applied in the preprocessing.Regarding ID decryption,targets and ISRJ can be recognized through the encryption and decryption processes,which are controlled by random keys.An adaptability analysis conducted in terms of the peak-to-side lobe ratio(PSLR)and bit error rate(BER)indicates that the proposed method performs well within a 70-k Hz Doppler shift.A simulation and experimental results show that the proposed method achieves extremely stable target and ISRJ recognition accuracies at different signal-to-noise ratios(SNRs)and jamming-to-signal ratios(JSRs).
文摘绝缘油是电抗器内部重要的绝缘介质,击穿电压是评估其绝缘特性的关键指标,与绝缘油的品质状态密切相关。本文共选取155组电抗器绝缘油进行实验,分别进行击穿电压的测定和多频超声信号在油样中传播衰减后信号的采集,分析多频超声声学参数和击穿电压之间的幅频响应、相频响应之间的关系,并基于多频超声检测技术提出结合灰狼优化算法(grey wolf optimizer,GWO)优化随机森林算法(random forest algorithm,RF)的击穿电压预测方法。结果表明:GWO-RF绝缘油击穿电压预测模型的预测值与实际值的平均相对误差为4.04%,预测准确率达到95.96%,相较于优化前的RF绝缘油击穿电压预测模型准确率提升了20.25%。结合多频超声检测技术和GWO-RF建立的并联电抗器绝缘油击穿电压预测模型,对击穿电压的预测具有可行性。
