GNSS navigation system has a shortage—the satellite navigation signal is vulnerable to various interferences and thus leads to losses in performance of received signal. Wideband interference is common oppressive which impact on the receiver performance badly. In this paper, aiming at the linear frequency modulation (LFM) wideband interference, a new interference suppression method based on NEW-MDCFT is presented, and the model and implementation method of the suppression algorithm have been introduced. By adding the LFM jamming to the COMPASS B1 signal, the interference suppression method is simulated, and time domain performance, frequency domain performance, acquisition performance and tracking performance of the signal before and after interference suppression have been given. The results indicate that, the suppression method based on NEW-MDCFT has good LFM interference suppression performance and is able to perform good interference suppression in seriously-interfered environment.
{"title":"A new wideband interference suppression method for GNSS system","authors":"Yan Bai, Xiaochun Lu, Tao Han, Jin Wang","doi":"10.1117/12.2182632","DOIUrl":"https://doi.org/10.1117/12.2182632","url":null,"abstract":"GNSS navigation system has a shortage—the satellite navigation signal is vulnerable to various interferences and thus leads to losses in performance of received signal. Wideband interference is common oppressive which impact on the receiver performance badly. In this paper, aiming at the linear frequency modulation (LFM) wideband interference, a new interference suppression method based on NEW-MDCFT is presented, and the model and implementation method of the suppression algorithm have been introduced. By adding the LFM jamming to the COMPASS B1 signal, the interference suppression method is simulated, and time domain performance, frequency domain performance, acquisition performance and tracking performance of the signal before and after interference suppression have been given. The results indicate that, the suppression method based on NEW-MDCFT has good LFM interference suppression performance and is able to perform good interference suppression in seriously-interfered environment.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"245 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131288575","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}
A novel method was proposed to measure the tilt error between the transit axis and standing axis of the laser tracker. A gradienter was first used to make the standing axis of the laser tracker perpendicular to the horizontal plane. The laser beam of the tracker was then projected onto a vertical plane set at a certain distance from the tracker with equal horizontal angles and diverse vertical angles in two-face mode. The contrail of the laser beam was recorded while the simulation was manipulated to estimate the beam trail under the same circumstance. The tilt error was thus obtained according to the comparison of the actual result against the simulated one. Experimental results showed that the accuracy of the tilt measuring method could meet the user’s demand.
{"title":"A novel method for measuring transit tilt error in laser trackers","authors":"Zili Zhang, Weihu Zhou, Han Zhu, Xinlong Lin","doi":"10.1117/12.2182383","DOIUrl":"https://doi.org/10.1117/12.2182383","url":null,"abstract":"A novel method was proposed to measure the tilt error between the transit axis and standing axis of the laser tracker. A gradienter was first used to make the standing axis of the laser tracker perpendicular to the horizontal plane. The laser beam of the tracker was then projected onto a vertical plane set at a certain distance from the tracker with equal horizontal angles and diverse vertical angles in two-face mode. The contrail of the laser beam was recorded while the simulation was manipulated to estimate the beam trail under the same circumstance. The tilt error was thus obtained according to the comparison of the actual result against the simulated one. Experimental results showed that the accuracy of the tilt measuring method could meet the user’s demand.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131121429","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}
As a widely used open-architecture computer bus ,VME bus is increasingly applied in military, aerospace, transportation and other large-scale control systems. Lithography, a very delicate and complicated integrated circuit manufacturing equipment, uses many circuit boards with VME interface in its control system, including one single-board computer, many movement control boards and one data acquisition board. This paper designs communication modules which include VME bus module and VME user-defined bus module for multi-boards in Lithography control system. VME bus module is designed for the communication between the single-board computer and movement control boards and VME user-defined bus is designed for the communication between movement control boards and data acquisition board. The experimental results demonstrate its effectiveness.
{"title":"Communication design for multi-boards based on VME bus","authors":"Yang Liu, Fazhi Song, Kai Wei, Zhenxian Fu","doi":"10.1117/12.2182254","DOIUrl":"https://doi.org/10.1117/12.2182254","url":null,"abstract":"As a widely used open-architecture computer bus ,VME bus is increasingly applied in military, aerospace, transportation and other large-scale control systems. Lithography, a very delicate and complicated integrated circuit manufacturing equipment, uses many circuit boards with VME interface in its control system, including one single-board computer, many movement control boards and one data acquisition board. This paper designs communication modules which include VME bus module and VME user-defined bus module for multi-boards in Lithography control system. VME bus module is designed for the communication between the single-board computer and movement control boards and VME user-defined bus is designed for the communication between movement control boards and data acquisition board. The experimental results demonstrate its effectiveness.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127509919","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}
A performance analysis and experiment validation of a pneumatic vibration isolator (PVI) that applied in the wafer stage of lithography is proposed in this work. The wafer stage of lithography is a dual-stage actuator system, including a long-stroke stage (LS) and a short-stroke stage (SS). In order to achieve the nanometer level positioning the isolator is designed to reduce the transmission of LS excitations to SS. In addition, considering the SS with six degrees of freedom and required to keep a strict constant temperature environment, the isolator need to have two functions, including the decoupling for vertical to horizontal and gravity compensation. In this isolator, a biaxial hinge was designed to decouple vertical rotation freedom, and a gas bearing was designed to decouple horizontal motion. The stiffness and damping of the pneumatic vibration isolator were analyzed. Besides, an analysis of the natural frequency and vibration transmissibility of the isolator is presented. In the end, the results show that vibration transmission is reduced significantly by the isolator and natural frequency can be lower than 0.6 Hz. This means that experimental results accord with the prediction model.
{"title":"Performance analysis and experiment validation of a pneumatic vibration isolator","authors":"Yuanyuan Yang, Jiubin Tan, Lei Wang, Tong Zhou","doi":"10.1117/12.2181188","DOIUrl":"https://doi.org/10.1117/12.2181188","url":null,"abstract":"A performance analysis and experiment validation of a pneumatic vibration isolator (PVI) that applied in the wafer stage of lithography is proposed in this work. The wafer stage of lithography is a dual-stage actuator system, including a long-stroke stage (LS) and a short-stroke stage (SS). In order to achieve the nanometer level positioning the isolator is designed to reduce the transmission of LS excitations to SS. In addition, considering the SS with six degrees of freedom and required to keep a strict constant temperature environment, the isolator need to have two functions, including the decoupling for vertical to horizontal and gravity compensation. In this isolator, a biaxial hinge was designed to decouple vertical rotation freedom, and a gas bearing was designed to decouple horizontal motion. The stiffness and damping of the pneumatic vibration isolator were analyzed. Besides, an analysis of the natural frequency and vibration transmissibility of the isolator is presented. In the end, the results show that vibration transmission is reduced significantly by the isolator and natural frequency can be lower than 0.6 Hz. This means that experimental results accord with the prediction model.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116975260","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}
W. Yue, Lei Zhang, Zhenya Guo, Shouzhen Jiang, Chengjie Bai
A portable and modularized fluorometer based on optical fiber was proposed in this work. The fluorometer included a light emitter diode (LED) light source module (LSM), a sample cell module (SCM), an optical-electrical converter module (OCM) and a signal process module (SAM). The LEDs in LSM were driven by a constant current source to provide stable exciting light with different wavelength. The OCM included a modularized optical filter and used a photomultiplier tube (PMT) to detect fluorescence signal. The SCM was used to locate sample cuvette and could be connected by optical fibers with the LSM and OCM. Via modularized design, the LSM and OCM could both selected and replaced based on different fluorescence dyes. In order to improve the detecting dynamic range of the fluorometer, the SAM could control the light intensity of LED source in LSM, to control the gain of PMT in OCM, and particularly, four channel signal acquisition circuits with different gain were constructed to collect fluorescence signal simultaneously. Fluorescein isothiocyanate (FITC) was selected as sample to test the fluorometer. The fluorometer has shown a high sensitivity with FITC concentration of 10ng/mL and presented a good linearity from 10 ng/mL to 10 μg/mL.
{"title":"Portable and modularized fluorometer based on optical fiber","authors":"W. Yue, Lei Zhang, Zhenya Guo, Shouzhen Jiang, Chengjie Bai","doi":"10.1117/12.2182022","DOIUrl":"https://doi.org/10.1117/12.2182022","url":null,"abstract":"A portable and modularized fluorometer based on optical fiber was proposed in this work. The fluorometer included a light emitter diode (LED) light source module (LSM), a sample cell module (SCM), an optical-electrical converter module (OCM) and a signal process module (SAM). The LEDs in LSM were driven by a constant current source to provide stable exciting light with different wavelength. The OCM included a modularized optical filter and used a photomultiplier tube (PMT) to detect fluorescence signal. The SCM was used to locate sample cuvette and could be connected by optical fibers with the LSM and OCM. Via modularized design, the LSM and OCM could both selected and replaced based on different fluorescence dyes. In order to improve the detecting dynamic range of the fluorometer, the SAM could control the light intensity of LED source in LSM, to control the gain of PMT in OCM, and particularly, four channel signal acquisition circuits with different gain were constructed to collect fluorescence signal simultaneously. Fluorescein isothiocyanate (FITC) was selected as sample to test the fluorometer. The fluorometer has shown a high sensitivity with FITC concentration of 10ng/mL and presented a good linearity from 10 ng/mL to 10 μg/mL.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115387596","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}
Yong Li, Shuai Wang, Z. Chu, Jie Tang, Yang Xu, Zhujun Ai, Hongtao Wang
The measuring force of a micro/nano probe is an important factor affecting the probe measurement accuracy. The strength of the force largely depends on the nature of the suspension structure. How to improve the flexibility of the suspension structure is a difficult issue. To tackle the problem, this paper will put forwards an integrated suspension structure, which composed of three evenly spaced elastic hinges. Each elastic hinge has two beams, one of which is used to as the support. In measurement, the maximum displacement is occurred at the intersection of the two beams. In this paper, the flexibility of the suspension structure and probe measuring capability related to the elastic hinge's size and material are investigated based on theoretical modeling and simulation. The research result is significant to reduce the probe measuring force and improve its sensitivity.
{"title":"A new suspension structure of micro/nano probe","authors":"Yong Li, Shuai Wang, Z. Chu, Jie Tang, Yang Xu, Zhujun Ai, Hongtao Wang","doi":"10.1117/12.2176017","DOIUrl":"https://doi.org/10.1117/12.2176017","url":null,"abstract":"The measuring force of a micro/nano probe is an important factor affecting the probe measurement accuracy. The strength of the force largely depends on the nature of the suspension structure. How to improve the flexibility of the suspension structure is a difficult issue. To tackle the problem, this paper will put forwards an integrated suspension structure, which composed of three evenly spaced elastic hinges. Each elastic hinge has two beams, one of which is used to as the support. In measurement, the maximum displacement is occurred at the intersection of the two beams. In this paper, the flexibility of the suspension structure and probe measuring capability related to the elastic hinge's size and material are investigated based on theoretical modeling and simulation. The research result is significant to reduce the probe measuring force and improve its sensitivity.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124834172","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}
Xian-sheng Li, Jianwei Ren, Z. Wan, Hong-xing Liu, Changxi Xue
The signal-to-noise ratio (SNR) and noise equivalent radiance (NER) are important characteristics of an electro-optical systems sensor. A new method to improve the system’s SNR and reduce the NER was studied by analyzing the radiometric calibration data of the system. An image was obtained, when the system was illuminated by the uniform light source outputting from integrating sphere. The adjourn pixels were binned by n×n pixels (n=2, 3, 4, 5) in this image. And the digital numbers of binning pixels were added together. The new images were achieved. With 5×5 pixels binned, the SNR increased from 165.7 up to 842.3, which is improved almost 5 times. At the same time, the NER decreased from 0.077(W/m2/sr) to 0.015(W/m2/sr), which is declined by nearly 5 times. With the binning pixels up to n×n, the SNR and NER were enhanced and decreased almost by n times, respectively.
{"title":"Improving signal-to-noise ratio and reducing noise equivalent radiance of electro-optical systems sensor by binning image pixels","authors":"Xian-sheng Li, Jianwei Ren, Z. Wan, Hong-xing Liu, Changxi Xue","doi":"10.1117/12.2181195","DOIUrl":"https://doi.org/10.1117/12.2181195","url":null,"abstract":"The signal-to-noise ratio (SNR) and noise equivalent radiance (NER) are important characteristics of an electro-optical systems sensor. A new method to improve the system’s SNR and reduce the NER was studied by analyzing the radiometric calibration data of the system. An image was obtained, when the system was illuminated by the uniform light source outputting from integrating sphere. The adjourn pixels were binned by n×n pixels (n=2, 3, 4, 5) in this image. And the digital numbers of binning pixels were added together. The new images were achieved. With 5×5 pixels binned, the SNR increased from 165.7 up to 842.3, which is improved almost 5 times. At the same time, the NER decreased from 0.077(W/m2/sr) to 0.015(W/m2/sr), which is declined by nearly 5 times. With the binning pixels up to n×n, the SNR and NER were enhanced and decreased almost by n times, respectively.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123420982","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}
The light field camera array can be regarded as distributed source. The image sequence captured by a camera array contains the inter-correlation and intra-correlation. In order to utilize the correlation, a joint sparsity model was established to combine the light field with distributed compressive sensing, and a recovery algorithm was proposed for the model -- simultaneous regularized orthogonal matching pursuit algorithm (SROMP), which uses the correlation to reconstruct the light field image sequences. Several light field images could be approximate at once using different linear combinations of elementary signals. Experimental results show that SROMP algorithm could be used to achieve high accuracy reported in the literatures.
{"title":"Distributed compressive sensing of light field","authors":"Rui Lei, Wei Shen, Zhijiang Zhang, Ying Zhou","doi":"10.1117/12.2181356","DOIUrl":"https://doi.org/10.1117/12.2181356","url":null,"abstract":"The light field camera array can be regarded as distributed source. The image sequence captured by a camera array contains the inter-correlation and intra-correlation. In order to utilize the correlation, a joint sparsity model was established to combine the light field with distributed compressive sensing, and a recovery algorithm was proposed for the model -- simultaneous regularized orthogonal matching pursuit algorithm (SROMP), which uses the correlation to reconstruct the light field image sequences. Several light field images could be approximate at once using different linear combinations of elementary signals. Experimental results show that SROMP algorithm could be used to achieve high accuracy reported in the literatures.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129699334","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}
A grating encoder, which is composed of two equal periodic planar gratings, is proposed for measuring wide range three-axis displacements with nanometric resolution. In the optical reading system, one grating works as a reference planar grating, while another one is a scale planar grating. The grating encoder records the x- and y-axis displacement information in terms of the grating period, while it records the z-axis displacement information in terms of both the wavelength of the laser and the grating period. In this scheme, the gratings and other optical elements satisfy the Littrow configuration. The positions and the size of the detected interference zones are almost constant when the scale grating moves along the z-axis with respect to the optical reading system. Therefore, the measurement range is greatly enhanced in the z-axis direction. When the wavelength of the laser is 632.8 nm and the scale grating with period 8 μm is 100×100 mm2, the measured maximal z-axis displacement of the proposed encoder is 1263 mm theoretically.
{"title":"Grating encoder for wide range three-axis displacement measurement","authors":"Jie Lin, Jian Guan, Feng Wen, Jun Luo, Peng Jin","doi":"10.1117/12.2082475","DOIUrl":"https://doi.org/10.1117/12.2082475","url":null,"abstract":"A grating encoder, which is composed of two equal periodic planar gratings, is proposed for measuring wide range three-axis displacements with nanometric resolution. In the optical reading system, one grating works as a reference planar grating, while another one is a scale planar grating. The grating encoder records the x- and y-axis displacement information in terms of the grating period, while it records the z-axis displacement information in terms of both the wavelength of the laser and the grating period. In this scheme, the gratings and other optical elements satisfy the Littrow configuration. The positions and the size of the detected interference zones are almost constant when the scale grating moves along the z-axis with respect to the optical reading system. Therefore, the measurement range is greatly enhanced in the z-axis direction. When the wavelength of the laser is 632.8 nm and the scale grating with period 8 μm is 100×100 mm2, the measured maximal z-axis displacement of the proposed encoder is 1263 mm theoretically.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125330095","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}
An angle interferometer was set up using concept ‘ratio of two lengths’ and an angle encoder was set up using concept ‘subdivision of full circle (2π rad=360°)’ at the National Institute of Metrology, China (NIM). For the analysis of the systematic errors of each device, two autocollimator calibration systems were separately set up based on the angle interferometer and the angle encoder with a similar measuring uncertainty (around 0.1″). An autocollimator was calibrated using two systems in the same measurement range (±1000″) and the same measurement step (10″). The systematic errors of each system were found through comparison between their original calibration results. The compensation curves were calculated using the analysis results, and two systems’ original calibration results were compensated according to two systems’ compensation curves. The maximum difference between the compensated calibration results of two systems was 0.05″ which is lower than measuring uncertainty of each system.
{"title":"Comparison between angle interferometer and angle encoder during calibration of autocollimator","authors":"Yao Huang, Z. Xue, Heyan Wang","doi":"10.1117/12.2180902","DOIUrl":"https://doi.org/10.1117/12.2180902","url":null,"abstract":"An angle interferometer was set up using concept ‘ratio of two lengths’ and an angle encoder was set up using concept ‘subdivision of full circle (2π rad=360°)’ at the National Institute of Metrology, China (NIM). For the analysis of the systematic errors of each device, two autocollimator calibration systems were separately set up based on the angle interferometer and the angle encoder with a similar measuring uncertainty (around 0.1″). An autocollimator was calibrated using two systems in the same measurement range (±1000″) and the same measurement step (10″). The systematic errors of each system were found through comparison between their original calibration results. The compensation curves were calculated using the analysis results, and two systems’ original calibration results were compensated according to two systems’ compensation curves. The maximum difference between the compensated calibration results of two systems was 0.05″ which is lower than measuring uncertainty of each system.","PeriodicalId":380636,"journal":{"name":"Precision Engineering Measurements and Instrumentation","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125405652","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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