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Article List
2023, 21(2):125-138.
DOI: 10.11805/TKYDA2022207
Abstract:
Rydberg atoms can be used for high-precision, self-calibrating measurements of microwave and terahertz fields due to their large polarizability and electric dipole moments and high sensitivity to external electric fields. In this paper, the research progress of using the Electromagnetically Induced Transparency(EIT) effect and the Autler-Townes(AT) splitting of Rydberg atoms to achieve high-precision detection of microwave and terahertz fields, is reviewed, as well as the research of Rydberg atoms in fast terahertz imaging.
Rydberg atoms can be used for high-precision, self-calibrating measurements of microwave and terahertz fields due to their large polarizability and electric dipole moments and high sensitivity to external electric fields. In this paper, the research progress of using the Electromagnetically Induced Transparency(EIT) effect and the Autler-Townes(AT) splitting of Rydberg atoms to achieve high-precision detection of microwave and terahertz fields, is reviewed, as well as the research of Rydberg atoms in fast terahertz imaging.
2023, 21(2):143-149.
DOI: 10.11805/TKYDA2022208
Abstract:
In this paper, a different network architecture is proposed for intelligent segmentation of THz security inspection images based on Generative Adversarial Network(GAN) and multi-head attention mechanism. The algorithm is prone to address the problems of low-resolution THz images, blurred edges of dangerous goods, and inability to segment dangerous goods efficiently. More realistic images are obtained by studying the feature map of the deep discriminator. The multi-head attention mechanism is introduced to improve the recognition ability of the model to the characteristics of dangerous goods. A large number of experimental results of segmentation of terahertz security inspection images show that the proposed GAN has better generalization ability at the same depth than the traditional Convolution Neural Networks(CNN).The introduction of multi-head attention mechanism strengthens the model's learning of the characteristics of dangerous goods, which also has a good effect in the case of unknown dangerous goods category. The Intersection Over Union(IOU) index is 9.6% higher than that of RestNet-50, 21.3% higher than that of RestNet-18, and 12.3% higher than that of U-Net. The research is conducive to image segmentation algorithms for more accurate and efficient processing of THz security images, which broadens further applications of THz intelligent security systems.
In this paper, a different network architecture is proposed for intelligent segmentation of THz security inspection images based on Generative Adversarial Network(GAN) and multi-head attention mechanism. The algorithm is prone to address the problems of low-resolution THz images, blurred edges of dangerous goods, and inability to segment dangerous goods efficiently. More realistic images are obtained by studying the feature map of the deep discriminator. The multi-head attention mechanism is introduced to improve the recognition ability of the model to the characteristics of dangerous goods. A large number of experimental results of segmentation of terahertz security inspection images show that the proposed GAN has better generalization ability at the same depth than the traditional Convolution Neural Networks(CNN).The introduction of multi-head attention mechanism strengthens the model's learning of the characteristics of dangerous goods, which also has a good effect in the case of unknown dangerous goods category. The Intersection Over Union(IOU) index is 9.6% higher than that of RestNet-50, 21.3% higher than that of RestNet-18, and 12.3% higher than that of U-Net. The research is conducive to image segmentation algorithms for more accurate and efficient processing of THz security images, which broadens further applications of THz intelligent security systems.
2023, 21(2):157-175.
DOI: 10.11805/TKYDA2022132
Abstract:
To design the optimal protection scheme for cultural relics of different materials and production techniques, the cultural heritage scientists are in constant search of the most effective nondestructive testing method for the overall survey of the cultural relics. Due to the unique properties of terahertz wave's low energy, strong penetrability for non-metallic and nonpolar substances, simultaneous measurement of amplitude and phase information, strong anti-interference capacity, etc., terahertz technology has been gaining an edge over other conventional nondestructive testing methods. In this review paper, the latest progress of terahertz technology applied in nondestructive testing of cultural relics are introduced, and the terahertz spectra characteristics of various cultural relics materials are illustrated. The principle and characteristics of terahertz imaging detection technology are expounded. The key issues in the application of terahertz nondestructive testing technology for various cultural relics are discussed, and the most successful and representative application examples of terahertz technology in cultural relics science are listed. Finally, we present the developing trend of terahertz nondestructive testing technology in the field of cultural relics.
To design the optimal protection scheme for cultural relics of different materials and production techniques, the cultural heritage scientists are in constant search of the most effective nondestructive testing method for the overall survey of the cultural relics. Due to the unique properties of terahertz wave's low energy, strong penetrability for non-metallic and nonpolar substances, simultaneous measurement of amplitude and phase information, strong anti-interference capacity, etc., terahertz technology has been gaining an edge over other conventional nondestructive testing methods. In this review paper, the latest progress of terahertz technology applied in nondestructive testing of cultural relics are introduced, and the terahertz spectra characteristics of various cultural relics materials are illustrated. The principle and characteristics of terahertz imaging detection technology are expounded. The key issues in the application of terahertz nondestructive testing technology for various cultural relics are discussed, and the most successful and representative application examples of terahertz technology in cultural relics science are listed. Finally, we present the developing trend of terahertz nondestructive testing technology in the field of cultural relics.
2023, 21(2):150-156.
DOI: 10.11805/TKYDA2022205
Abstract:
Terahertz Time Domain Spectroscopy(THz-TDS) is employed to detect the Zinc Citrate(ZC) dihydrate and its dehydration kinetics. Results show that there are two prominent absorption peaks:one at 1.91 THz, the other at 1.77 THz for the ZC dihydrate, while there is no featuring absorption peak for ZC anhydrate at room temperature. When the temperature increases, the absorption peak of ZC dihydrate at 1.91 THz decreases and gradually disappears. According to the variation of the absorption peak area of ZC dihydrate at 1.91 THz under different temperatures and heating time, the enthalpy change of ZC dihydrate transforming to anhydrate is 381.13 J/g(232.6 kJ/mol) by using the Arrhenius equation, and the error is 4.2% compared with the traditional Differential Scanning Calorimetry(DSC) measurement. These results indicate that THz-TDS can be used as an efficient and fast technique for the detection of ZC dihydrate and its dehydration kinetics.
Terahertz Time Domain Spectroscopy(THz-TDS) is employed to detect the Zinc Citrate(ZC) dihydrate and its dehydration kinetics. Results show that there are two prominent absorption peaks:one at 1.91 THz, the other at 1.77 THz for the ZC dihydrate, while there is no featuring absorption peak for ZC anhydrate at room temperature. When the temperature increases, the absorption peak of ZC dihydrate at 1.91 THz decreases and gradually disappears. According to the variation of the absorption peak area of ZC dihydrate at 1.91 THz under different temperatures and heating time, the enthalpy change of ZC dihydrate transforming to anhydrate is 381.13 J/g(232.6 kJ/mol) by using the Arrhenius equation, and the error is 4.2% compared with the traditional Differential Scanning Calorimetry(DSC) measurement. These results indicate that THz-TDS can be used as an efficient and fast technique for the detection of ZC dihydrate and its dehydration kinetics.
2023, 21(2):139-142.
DOI: 10.11805/TKYDA2022199
Abstract:
Aiming at the requirements of millimeter and sub millimeter wave radiometer for quasi optical feed network, a 23~425 GHz ten channels quasi optical feed network is designed by GRASP software, using flat plane to achieve a double layers quasi optical feed network and reduce the size,using polarization grids and Frequency Selective Surfaces(FSS) to separate different channels. Through simulating the specifications of each channel, the test results are consistent with the simulation results.
Aiming at the requirements of millimeter and sub millimeter wave radiometer for quasi optical feed network, a 23~425 GHz ten channels quasi optical feed network is designed by GRASP software, using flat plane to achieve a double layers quasi optical feed network and reduce the size,using polarization grids and Frequency Selective Surfaces(FSS) to separate different channels. Through simulating the specifications of each channel, the test results are consistent with the simulation results.
