A terahertz (THz) imaging system based on air ionizing in two color laser fields is demonstrated. A 1mm thick (110)-oriented ZnTe is used for electro-optic sampling crystal. The depth of modulation of THz is 0.8%, which is much lager than that of optical rectification in ZnTe. Minus the background, the transmission images of the THz focus and a moving metal rod are demonstrated. The imaging speed is 34 fps. It is very useful to observe the movement of objects with terahertz in real time.
{"title":"THz real time imaging based on air ionizing in two color laser fields","authors":"Chao Meng, Dong-Wen Zhang, Zhi-hui Lv, Xiyu Du, Zengxiu Zhao, Jianmin Yuan","doi":"10.1117/12.901629","DOIUrl":"https://doi.org/10.1117/12.901629","url":null,"abstract":"A terahertz (THz) imaging system based on air ionizing in two color laser fields is demonstrated. A 1mm thick (110)-oriented ZnTe is used for electro-optic sampling crystal. The depth of modulation of THz is 0.8%, which is much lager than that of optical rectification in ZnTe. Minus the background, the transmission images of the THz focus and a moving metal rod are demonstrated. The imaging speed is 34 fps. It is very useful to observe the movement of objects with terahertz in real time.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114509458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Restoration of atmospheric turbulence-degraded image is needed to be solved as soon as possible in the field of astronomical space technology. This paper discusses the issue of regularization during the restoration process, a new restoration method of heavy turbulence-degrade image for space target based on regularization is proposed, in which the anisotropic, nonlinear Step-like and Gussian-like regularization models are adopted according to the properties of turbulence point spread function(PSF)and image. The nonlinear regularization functions are suggested to smooth in the process of estimating the PSF and recover the object image. In order to test the validity of the method, a series of restoration experiments are performed on the heavy turbulence-degraded images for space target and the experiment results show that the method is effective to restore the space object from their heavy turbulence-degraded images. Besides, the definition measures and relative definition measures show that the new method is better than the traditional method for restoration result.
{"title":"Restoration algorithm of heavy turbulence degraded image for space target based on regularization","authors":"Liang-liang Wang, Zhi-wei Tao, Ming Li, Xin Gao","doi":"10.1117/12.899877","DOIUrl":"https://doi.org/10.1117/12.899877","url":null,"abstract":"Restoration of atmospheric turbulence-degraded image is needed to be solved as soon as possible in the field of astronomical space technology. This paper discusses the issue of regularization during the restoration process, a new restoration method of heavy turbulence-degrade image for space target based on regularization is proposed, in which the anisotropic, nonlinear Step-like and Gussian-like regularization models are adopted according to the properties of turbulence point spread function(PSF)and image. The nonlinear regularization functions are suggested to smooth in the process of estimating the PSF and recover the object image. In order to test the validity of the method, a series of restoration experiments are performed on the heavy turbulence-degraded images for space target and the experiment results show that the method is effective to restore the space object from their heavy turbulence-degraded images. Besides, the definition measures and relative definition measures show that the new method is better than the traditional method for restoration result.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"252 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117318086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High sensitivity and SNR are requested in lunar astronomical observation in order to get dark and feeble objects. Scientific CCD Cameras used in lunar astronomical observation usually have following characteristics: high quantum efficiency, wide spectral response, good photometric linearity and wide dynamic range. However, extremely low readout noise is usually a key indicator of the camera. A CCD camera, based on E2V's back-illuminated ultraviolet-enhanced scientific grade AIMO image sensor, has been designed for lunar astronomical observation. Four major kinds of electrical optimal design are presented in order to reduce the readout noise of the camera. The experiment result shows that: in the 200K pix/s of the pixel clock, the camera system gain is 1.83e-/ADU, and the readout noise is less than 6e-.
{"title":"Development of low readout noise scientific CCD camera for lunar astronomical observation","authors":"Wei Ge, Yu-quan Gan, Hong Wang, Guang-zhou Xu","doi":"10.1117/12.900695","DOIUrl":"https://doi.org/10.1117/12.900695","url":null,"abstract":"High sensitivity and SNR are requested in lunar astronomical observation in order to get dark and feeble objects. Scientific CCD Cameras used in lunar astronomical observation usually have following characteristics: high quantum efficiency, wide spectral response, good photometric linearity and wide dynamic range. However, extremely low readout noise is usually a key indicator of the camera. A CCD camera, based on E2V's back-illuminated ultraviolet-enhanced scientific grade AIMO image sensor, has been designed for lunar astronomical observation. Four major kinds of electrical optimal design are presented in order to reduce the readout noise of the camera. The experiment result shows that: in the 200K pix/s of the pixel clock, the camera system gain is 1.83e-/ADU, and the readout noise is less than 6e-.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116449762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pulse position modulation (PPM) provides a means of using high peak power lasers for transmitting communications signals from planetary spacecraft to earth-based receiving stations. In this paper, we use avalanche photodiode (APD) as the receiver, on the basis of analyzing channel model of atmospheric laser communication, do deeply researches on the performance of PPM optical pulse system that influenced by timing error, draw a conclusion on the relation between frames error rate of strong, weak turbulent environment and normalized timing error respectively. In addition, on the condition of existing timing error in the system, we obtain satisfactory results by simulation on how the change of parameters including flicker index, APD average gain, level of PPM modulation influence the performance of PPM optical pulse system.
{"title":"The performance analysis of PPM optical system in atmospheric turbulent channel","authors":"Yu E., Xiao-li Yang, Wei Fan","doi":"10.1117/12.899454","DOIUrl":"https://doi.org/10.1117/12.899454","url":null,"abstract":"Pulse position modulation (PPM) provides a means of using high peak power lasers for transmitting communications signals from planetary spacecraft to earth-based receiving stations. In this paper, we use avalanche photodiode (APD) as the receiver, on the basis of analyzing channel model of atmospheric laser communication, do deeply researches on the performance of PPM optical pulse system that influenced by timing error, draw a conclusion on the relation between frames error rate of strong, weak turbulent environment and normalized timing error respectively. In addition, on the condition of existing timing error in the system, we obtain satisfactory results by simulation on how the change of parameters including flicker index, APD average gain, level of PPM modulation influence the performance of PPM optical pulse system.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122055111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hua-yong Shi, Y. Jiang, Zhibin Sun, Xue Liu, Shangqi Gao
Deep space life exploration nowadays mainly focuses on whether environments on other planets are suitable for the existence of life. This has not hit the key point. As life depending on its specified conditions, it is of great necessity and importance to conduct exploration in the life's original environment. An idea was put forward in this paper to detect specific life forms in the original environment if they exist. This idea, based on fluorescence, included light source unit and detection unit. The former was optical fiber coupled LED and lens; the latter was charge coupled device (CCD) and other lens. Light from LED was collected and transferred by optical fiber, then purified by a filter in order to obtain specific wavelength light, which could excite corresponding organic biological molecules. These molecules emitted light of other wavelength, usually referred to as fluorescence, the moment they were illuminated by excitation light. The fluorescence was also purified by another filter. Then lens was used to collect the light. As to detection device, CCD would give fluorescence image. Theoretical analysis demonstrated that the system could meet the task's requirements. During test in laboratory, this system performed well, too. CCD could output desired signals. This provided strong support that the idea present in the paper is feasible and is of practical significance.
{"title":"The research of deep space life exploration based on fluorescence","authors":"Hua-yong Shi, Y. Jiang, Zhibin Sun, Xue Liu, Shangqi Gao","doi":"10.1117/12.900771","DOIUrl":"https://doi.org/10.1117/12.900771","url":null,"abstract":"Deep space life exploration nowadays mainly focuses on whether environments on other planets are suitable for the existence of life. This has not hit the key point. As life depending on its specified conditions, it is of great necessity and importance to conduct exploration in the life's original environment. An idea was put forward in this paper to detect specific life forms in the original environment if they exist. This idea, based on fluorescence, included light source unit and detection unit. The former was optical fiber coupled LED and lens; the latter was charge coupled device (CCD) and other lens. Light from LED was collected and transferred by optical fiber, then purified by a filter in order to obtain specific wavelength light, which could excite corresponding organic biological molecules. These molecules emitted light of other wavelength, usually referred to as fluorescence, the moment they were illuminated by excitation light. The fluorescence was also purified by another filter. Then lens was used to collect the light. As to detection device, CCD would give fluorescence image. Theoretical analysis demonstrated that the system could meet the task's requirements. During test in laboratory, this system performed well, too. CCD could output desired signals. This provided strong support that the idea present in the paper is feasible and is of practical significance.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122072636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have investigated the effect of a moderately strong magnetic field (generated by superconducting coil, up to 380Gauss, 6 quantum fluxes within a single junction; generated by one piece of permanent magnet; generated by two pieces of permanent magnets respectively) on Nb superconducting tunnel junctions at different temperatures. Both experimental and numerical results show that the superconducting tunnel junction DC Josephson current can be significantly reduced by a magnetic field. A relatively strong magnet field may suppress the gap voltage as well as the sharp nonlinearity at the gap. We also investigated the leakage current and DC Josephson current of the Nb SIS junction at different temperatures.
{"title":"Magnetic effects on THz superconducting tunnel junctions at different temperatures","authors":"Chengjiang Zhang, Q. Yao, S. Shi","doi":"10.1117/12.900323","DOIUrl":"https://doi.org/10.1117/12.900323","url":null,"abstract":"We have investigated the effect of a moderately strong magnetic field (generated by superconducting coil, up to 380Gauss, 6 quantum fluxes within a single junction; generated by one piece of permanent magnet; generated by two pieces of permanent magnets respectively) on Nb superconducting tunnel junctions at different temperatures. Both experimental and numerical results show that the superconducting tunnel junction DC Josephson current can be significantly reduced by a magnetic field. A relatively strong magnet field may suppress the gap voltage as well as the sharp nonlinearity at the gap. We also investigated the leakage current and DC Josephson current of the Nb SIS junction at different temperatures.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117100433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Being an efficient method of information fusion, image fusion has been used in many fields such as machine vision, medical diagnosis, military applications and remote sensing. In this paper, Pulse Coupled Neural Network (PCNN) is introduced in this research field for its interesting properties in image processing, including segmentation, target recognition et al. and a novel algorithm based on PCNN and Wavelet Transform for Multi-focus image fusion is proposed. First, the two original images are decomposed by wavelet transform. Then, based on the PCNN, a fusion rule in the Wavelet domain is given. This algorithm uses the wavelet coefficient in each frequency domain as the linking strength, so that its value can be chosen adaptively. Wavelet coefficients map to the range of image gray-scale. The output threshold function attenuates to minimum gray over time. Then all pixels of image get the ignition. So, the output of PCNN in each iteration time is ignition wavelet coefficients of threshold strength in different time. At this moment, the sequences of ignition of wavelet coefficients represent ignition timing of each neuron. The ignition timing of PCNN in each neuron is mapped to corresponding image gray-scale range, which is a picture of ignition timing mapping. Then it can judge the targets in the neuron are obvious features or not obvious. The fusion coefficients are decided by the compare-selection operator with the firing time gradient maps and the fusion image is reconstructed by wavelet inverse transform. Furthermore, by this algorithm, the threshold adjusting constant is estimated by appointed iteration number. Furthermore, In order to sufficient reflect order of the firing time, the threshold adjusting constant αΘ is estimated by appointed iteration number. So after the iteration achieved, each of the wavelet coefficient is activated. In order to verify the effectiveness of proposed rules, the experiments upon Multi-focus image are done. Moreover, comparative results of evaluating fusion quality are listed. The experimental results show that the method can effectively enhance the edge details and improve the spatial resolution of the image.
{"title":"Multi-focus image fusion algorithm based on adaptive PCNN and wavelet transform","authors":"Zhi-guo Wu, Ming-jia Wang, G. Han","doi":"10.1117/12.899653","DOIUrl":"https://doi.org/10.1117/12.899653","url":null,"abstract":"Being an efficient method of information fusion, image fusion has been used in many fields such as machine vision, medical diagnosis, military applications and remote sensing. In this paper, Pulse Coupled Neural Network (PCNN) is introduced in this research field for its interesting properties in image processing, including segmentation, target recognition et al. and a novel algorithm based on PCNN and Wavelet Transform for Multi-focus image fusion is proposed. First, the two original images are decomposed by wavelet transform. Then, based on the PCNN, a fusion rule in the Wavelet domain is given. This algorithm uses the wavelet coefficient in each frequency domain as the linking strength, so that its value can be chosen adaptively. Wavelet coefficients map to the range of image gray-scale. The output threshold function attenuates to minimum gray over time. Then all pixels of image get the ignition. So, the output of PCNN in each iteration time is ignition wavelet coefficients of threshold strength in different time. At this moment, the sequences of ignition of wavelet coefficients represent ignition timing of each neuron. The ignition timing of PCNN in each neuron is mapped to corresponding image gray-scale range, which is a picture of ignition timing mapping. Then it can judge the targets in the neuron are obvious features or not obvious. The fusion coefficients are decided by the compare-selection operator with the firing time gradient maps and the fusion image is reconstructed by wavelet inverse transform. Furthermore, by this algorithm, the threshold adjusting constant is estimated by appointed iteration number. Furthermore, In order to sufficient reflect order of the firing time, the threshold adjusting constant αΘ is estimated by appointed iteration number. So after the iteration achieved, each of the wavelet coefficient is activated. In order to verify the effectiveness of proposed rules, the experiments upon Multi-focus image are done. Moreover, comparative results of evaluating fusion quality are listed. The experimental results show that the method can effectively enhance the edge details and improve the spatial resolution of the image.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117119677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hou-zhi Cai, Jinyuan Liu, Xiang Peng, L. Niu, W. Peng, J. Long
Microchannel plate (MCP) is a core part of the X-ray framing camera. Studying the dynamic characteristics of the MCP is critical to understanding the data obtained by the framing camera. The dynamic characteristics of the MCP with different dc bias voltage are simulated by using the Monte Carlo method. The relationship between the theoretical exposure time and the MCP bias voltage is obtained. A MCP gated X-ray framing camera is developed. The measured exposure time increase 9 ps while the MCP bias voltage is -300 V comparing to -200 V. The simulation and experimental results show that the exposure time and gain of the MCP are both increased while the negative bias voltage is increased.
{"title":"The MCP dynamic characteristics with different bias voltage","authors":"Hou-zhi Cai, Jinyuan Liu, Xiang Peng, L. Niu, W. Peng, J. Long","doi":"10.1117/12.900180","DOIUrl":"https://doi.org/10.1117/12.900180","url":null,"abstract":"Microchannel plate (MCP) is a core part of the X-ray framing camera. Studying the dynamic characteristics of the MCP is critical to understanding the data obtained by the framing camera. The dynamic characteristics of the MCP with different dc bias voltage are simulated by using the Monte Carlo method. The relationship between the theoretical exposure time and the MCP bias voltage is obtained. A MCP gated X-ray framing camera is developed. The measured exposure time increase 9 ps while the MCP bias voltage is -300 V comparing to -200 V. The simulation and experimental results show that the exposure time and gain of the MCP are both increased while the negative bias voltage is increased.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124086028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For the purpose of security inspection, an alternating current (AC) radiometer is used in passive THz Wave (0.1THz) imaging for the first time in china. Giving a comparison of structure and spectrum characteristic between direct current (DC) radiometer and AC radiometer, we discussed the AC radiometer imaging mechanism and the noise image disposal method based on the medium filtering. Simulating the requirement of safety inspection in airports, ports etc, a 2-D imaging experiment of the person with canceled object has been did indoor, by THz Wave AC radiometer mechanical scanning. The results show that THz Wave AC radiometer possesses higher sensitivity and can be used to inspect the concealed metal objects hidden in the passenger body and their luggage.
{"title":"Research on 0.1THz alternating current radiometric security inspection imaging for antiterrorism application","authors":"Guang-feng Zhang, W. Qin, Guo-wei Lou","doi":"10.1117/12.899604","DOIUrl":"https://doi.org/10.1117/12.899604","url":null,"abstract":"For the purpose of security inspection, an alternating current (AC) radiometer is used in passive THz Wave (0.1THz) imaging for the first time in china. Giving a comparison of structure and spectrum characteristic between direct current (DC) radiometer and AC radiometer, we discussed the AC radiometer imaging mechanism and the noise image disposal method based on the medium filtering. Simulating the requirement of safety inspection in airports, ports etc, a 2-D imaging experiment of the person with canceled object has been did indoor, by THz Wave AC radiometer mechanical scanning. The results show that THz Wave AC radiometer possesses higher sensitivity and can be used to inspect the concealed metal objects hidden in the passenger body and their luggage.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124397932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we present a novel method for visibility enhancement based on atmospheric scattering imaging models. Given only a single degraded image, we firstly estimate global atmospheric light vector based on dark channel prior. Then fast bilateral filter is used to deduce atmospheric veil, which is the key contribution of this paper. Following these, the ideal scene radiance could be recovered by directly solving physics-based imaging equation finally. The main advantage of our weather removal algorithm is that, it does not require any a priori scene structure, distributions of scene reflectance, or detailed knowledge about the particular weather condition, and could achieve similar or better restoration results with only a fraction of time consumption in contrast to state-of-art techniques both for color and grey images. Experiments results demonstrate that out algorithm could significantly enhance the details of hazy images, which is very important for features extraction and robust tracking for out-door vision system.
{"title":"Visibility enhancement for robust tracking under bad weather","authors":"Sun Kang, Wang Bo","doi":"10.1117/12.901047","DOIUrl":"https://doi.org/10.1117/12.901047","url":null,"abstract":"In this paper, we present a novel method for visibility enhancement based on atmospheric scattering imaging models. Given only a single degraded image, we firstly estimate global atmospheric light vector based on dark channel prior. Then fast bilateral filter is used to deduce atmospheric veil, which is the key contribution of this paper. Following these, the ideal scene radiance could be recovered by directly solving physics-based imaging equation finally. The main advantage of our weather removal algorithm is that, it does not require any a priori scene structure, distributions of scene reflectance, or detailed knowledge about the particular weather condition, and could achieve similar or better restoration results with only a fraction of time consumption in contrast to state-of-art techniques both for color and grey images. Experiments results demonstrate that out algorithm could significantly enhance the details of hazy images, which is very important for features extraction and robust tracking for out-door vision system.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128742687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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