VR installation and detection tasks require the ranging system to combine a high accuracy with a large depth of field and to collect reflection peaks from multiple reflective surfaces. Currently, there is no corresponding device to assist VR optical assembly detection, including tilt, eccentricity, and spacing of lens assembly. To fill this gap, this study applied the FMCW lidar-based ranging system to VR optical testing. Through nonlinear correction and introducing an axicon lens in the optical system, a high-precision FMCW ranging system with a 20 mm depth of field was obtained. The ranging accuracy and ranging resolution of the system could reach 1.3 μm and 14.3 μm, respectively, and the planes of the three glass layers could be simultaneously measured. The proposed system application made it possible to perform the installation and adjustment detection of the multi-lens optical system of VR.
{"title":"FMCW LiDAR-based ranging system application to VR optical measurement","authors":"Bing Dai, Yongyan Xie, Jiajing Wu, Yingjie Peng","doi":"10.1117/12.2667878","DOIUrl":"https://doi.org/10.1117/12.2667878","url":null,"abstract":"VR installation and detection tasks require the ranging system to combine a high accuracy with a large depth of field and to collect reflection peaks from multiple reflective surfaces. Currently, there is no corresponding device to assist VR optical assembly detection, including tilt, eccentricity, and spacing of lens assembly. To fill this gap, this study applied the FMCW lidar-based ranging system to VR optical testing. Through nonlinear correction and introducing an axicon lens in the optical system, a high-precision FMCW ranging system with a 20 mm depth of field was obtained. The ranging accuracy and ranging resolution of the system could reach 1.3 μm and 14.3 μm, respectively, and the planes of the three glass layers could be simultaneously measured. The proposed system application made it possible to perform the installation and adjustment detection of the multi-lens optical system of VR.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121858057","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}
Shun Liu, P. Zhu, Zhecong Lin, Yabin Zhou, M. Soto
The warpage deformation of a silicon plate is monitored in real-time using distributed optical fiber and the influence of data resolution on the measurement result is studied. The experimental results show that this method has good accuracy and the relationship between data resolution and measurement error is non-linear.
{"title":"Real-time warpage deformation monitoring using distributed optical fiber sensing","authors":"Shun Liu, P. Zhu, Zhecong Lin, Yabin Zhou, M. Soto","doi":"10.1117/12.2668453","DOIUrl":"https://doi.org/10.1117/12.2668453","url":null,"abstract":"The warpage deformation of a silicon plate is monitored in real-time using distributed optical fiber and the influence of data resolution on the measurement result is studied. The experimental results show that this method has good accuracy and the relationship between data resolution and measurement error is non-linear.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129026675","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}
Chen Shen, Jinlan Zhang, Teng Zhu, C. Yue, Wanqiu Zhang
Forest canopy structure is an important parameter for measuring forest changes and forest coverages. It is significant to explore the application of TerraSAR-X/TanDEM-X data in tree height inversion. In this research, the phase difference-phase coherence magnitude algorithm and the digital elevation model (DEM) method were investigated based on the random-volume-over-ground (RVoG) model. With Mengla County in Xishuangbanna Dai Autonomous Prefecture in Yunnan Province as the research area, the forest height inversion was performed based on TerraSAR-X/TanDEM-X data. Finally, the results were verified by combining field-measured data. For natural forests and rubber plantations, the DEM height difference method magnitude tree height inversion algorithm improves the estimation of the earth phase and canopy phase favorably, while the traditional algorithm presents a high height inversion precision for rubber plantations.
{"title":"Research on forest height inversion algorithm based on X-band SAR data","authors":"Chen Shen, Jinlan Zhang, Teng Zhu, C. Yue, Wanqiu Zhang","doi":"10.1117/12.2667940","DOIUrl":"https://doi.org/10.1117/12.2667940","url":null,"abstract":"Forest canopy structure is an important parameter for measuring forest changes and forest coverages. It is significant to explore the application of TerraSAR-X/TanDEM-X data in tree height inversion. In this research, the phase difference-phase coherence magnitude algorithm and the digital elevation model (DEM) method were investigated based on the random-volume-over-ground (RVoG) model. With Mengla County in Xishuangbanna Dai Autonomous Prefecture in Yunnan Province as the research area, the forest height inversion was performed based on TerraSAR-X/TanDEM-X data. Finally, the results were verified by combining field-measured data. For natural forests and rubber plantations, the DEM height difference method magnitude tree height inversion algorithm improves the estimation of the earth phase and canopy phase favorably, while the traditional algorithm presents a high height inversion precision for rubber plantations.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130195721","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 spin polarization of 87Rb and 129Xe atomic ensemble has great impact on the signal intensity of a nuclear magnetic resonance gyroscope. The coupled spin polarization modelling process for 87Rb and 129Xe atoms ensemble is presented in detail. Three dimensional spatial distribution of the spin polarization field is obtained by numerical solution and is in good agreement with the experiment results. Influencing factors including temperature, power and detuned frequency of the pumping laser, average collision times of anti-relaxation coatings and partial pressure of gas composition are investigated. The work presents an indirect method to estimate the average collision times given the Xe polarization with different temperatures. It is found the average collision times of the 129Xe atoms with the inner surface of a bare glass cell of 3×3×3mm3 can reach up to about 2.7×105 times. It is also found that the pumping frequency corresponding to the maximum polarization of the Xe atoms polarized by spin exchange of Rb atoms is not consistent with the D1 line of the 87Rb atom when the temperature of the cell is above a certain temperature, but is detuned at a certain frequency. Quantitative analysis of the effect of anti-relaxation coatings on the spin polarization suggests that the appropriate average number of collisions of the Rb atoms with the inner surface of the cell is about 1500 times.
{"title":"Investigation of spatial spin polarization of 87Rb and 129Xe atomic ensemble pumped by Gaussian beam in a miniature nuclear magnetic resonance gyroscope","authors":"Shu Qiang, Ji Fang","doi":"10.1117/12.2667783","DOIUrl":"https://doi.org/10.1117/12.2667783","url":null,"abstract":"The spin polarization of 87Rb and 129Xe atomic ensemble has great impact on the signal intensity of a nuclear magnetic resonance gyroscope. The coupled spin polarization modelling process for 87Rb and 129Xe atoms ensemble is presented in detail. Three dimensional spatial distribution of the spin polarization field is obtained by numerical solution and is in good agreement with the experiment results. Influencing factors including temperature, power and detuned frequency of the pumping laser, average collision times of anti-relaxation coatings and partial pressure of gas composition are investigated. The work presents an indirect method to estimate the average collision times given the Xe polarization with different temperatures. It is found the average collision times of the 129Xe atoms with the inner surface of a bare glass cell of 3×3×3mm3 can reach up to about 2.7×105 times. It is also found that the pumping frequency corresponding to the maximum polarization of the Xe atoms polarized by spin exchange of Rb atoms is not consistent with the D1 line of the 87Rb atom when the temperature of the cell is above a certain temperature, but is detuned at a certain frequency. Quantitative analysis of the effect of anti-relaxation coatings on the spin polarization suggests that the appropriate average number of collisions of the Rb atoms with the inner surface of the cell is about 1500 times.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127737359","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 the process of aligning and assembling prefabricated segmental beams, the measurement method of using total station to obtain spatial pose has the problems of high manual dependence, low measurement efficiency and high construction risk. The existing non-contact measurement methods are analyzed. It is concluded that photogrammetry has the conditions to realize automatic measurement and can reduce certain construction risks. According to the complex situation of bridge construction site and the harsh environment, traditional camera calibration methods are not applicable. Therefore, a self-calibration method is proposed. At the same time, according to the self-calibration algorithm, all photos taken cannot be solved, and there are problems of photo redundancy. The algorithm is further optimized to obtain a focal length calibration method based on global scanning, and the camera shooting is used to test and verify the construction site of prefabricated segmental beam assembly to explore whether the measurement accuracy of the method can meet the construction requirements in the actual construction environment. The results show that the measurement method can be realized in the construction environment of precast segmental beams. And the measurement accuracy meets the assembly requirements of precast segmental beams.
{"title":"Research and verification of space position of precast segmental beam based on photogrammetry","authors":"ChenYang Fan, Maolin Cheng, Hao Xiao, Zhangyan Zhao","doi":"10.1117/12.2667859","DOIUrl":"https://doi.org/10.1117/12.2667859","url":null,"abstract":"In the process of aligning and assembling prefabricated segmental beams, the measurement method of using total station to obtain spatial pose has the problems of high manual dependence, low measurement efficiency and high construction risk. The existing non-contact measurement methods are analyzed. It is concluded that photogrammetry has the conditions to realize automatic measurement and can reduce certain construction risks. According to the complex situation of bridge construction site and the harsh environment, traditional camera calibration methods are not applicable. Therefore, a self-calibration method is proposed. At the same time, according to the self-calibration algorithm, all photos taken cannot be solved, and there are problems of photo redundancy. The algorithm is further optimized to obtain a focal length calibration method based on global scanning, and the camera shooting is used to test and verify the construction site of prefabricated segmental beam assembly to explore whether the measurement accuracy of the method can meet the construction requirements in the actual construction environment. The results show that the measurement method can be realized in the construction environment of precast segmental beams. And the measurement accuracy meets the assembly requirements of precast segmental beams.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128297321","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}
When two aircraft interact in an aerial refueling operation (confluence, pre-docking, docking and separation), it is challenging for pilots alone to control the distance and speed between the two aircrafts. Based on GPS dynamic differential equipment, this paper studies the relative positioning algorithm that measures the relative position between the refueling probe and drogue, forming a unified coordinate system of the moving space platform. This method builds a high-precision, stable and reliable two-machine relative position measurement special system and provides auxiliary guidance and safety warning for the aerial refueling process.
{"title":"Research on relative positioning algorithm for large aircraft aerial refueling","authors":"Jun Yu Li, Jixuan Zhang","doi":"10.1117/12.2667896","DOIUrl":"https://doi.org/10.1117/12.2667896","url":null,"abstract":"When two aircraft interact in an aerial refueling operation (confluence, pre-docking, docking and separation), it is challenging for pilots alone to control the distance and speed between the two aircrafts. Based on GPS dynamic differential equipment, this paper studies the relative positioning algorithm that measures the relative position between the refueling probe and drogue, forming a unified coordinate system of the moving space platform. This method builds a high-precision, stable and reliable two-machine relative position measurement special system and provides auxiliary guidance and safety warning for the aerial refueling process.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"352 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128955162","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}
Dongfang Guo, Yuan Gao, Hongzhi Yang, Junru Zhou, Y. Mao, Zi-li Zhang, L. Wang
The excellent properties of the narrow linewidth, single longitudinal mode and constant frequency of the seed-injected solid-state single-frequency pulse laser make it suitable in the applications of the gravitational wave detection, doppler wind radar, and greenhouse gas flux measurement. FPGAs have been widely utilized in the laser electronic control systems due to its high integration and parallel processing capabilities. Based on the classical Ramp-Hold-Fire principle, we develop an injection locking system by using the modular FPGA architecture and the Verilog programming language. To demonstrate the program's viability, Vivado software is utilized for online simulation and debugging to guarantee the correctness of time conversion between different modules. The simulation results show a good time match between the master and slave lasers. The realization of seed injection locking is verified by detecting the increase of output laser energy, shortening pulse setup time and single longitudinal mode output pulse after injection. Finally, a 2 μm single frequency pulse laser is generated with a repetition rate 300 Hz and output power 4.5 mJ.
{"title":"Design of seed laser injection locking system for 2μm solid-state laser based on FPGA","authors":"Dongfang Guo, Yuan Gao, Hongzhi Yang, Junru Zhou, Y. Mao, Zi-li Zhang, L. Wang","doi":"10.1117/12.2667935","DOIUrl":"https://doi.org/10.1117/12.2667935","url":null,"abstract":"The excellent properties of the narrow linewidth, single longitudinal mode and constant frequency of the seed-injected solid-state single-frequency pulse laser make it suitable in the applications of the gravitational wave detection, doppler wind radar, and greenhouse gas flux measurement. FPGAs have been widely utilized in the laser electronic control systems due to its high integration and parallel processing capabilities. Based on the classical Ramp-Hold-Fire principle, we develop an injection locking system by using the modular FPGA architecture and the Verilog programming language. To demonstrate the program's viability, Vivado software is utilized for online simulation and debugging to guarantee the correctness of time conversion between different modules. The simulation results show a good time match between the master and slave lasers. The realization of seed injection locking is verified by detecting the increase of output laser energy, shortening pulse setup time and single longitudinal mode output pulse after injection. Finally, a 2 μm single frequency pulse laser is generated with a repetition rate 300 Hz and output power 4.5 mJ.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121682577","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 order to ensure that China's mineral industry can achieve higher benefits and improve work efficiency, mineral enterprises should make dynamic detection and mapping of the geological conditions of mines in time, and take the accurate mapping results as the actual basis in the mining process. Therefore, it is necessary to monitor the complex mine environment, effectively deal with emergencies under the concept of sustainable development strategy, and ensure mine production safety and ecological balance.
{"title":"Application of three-dimensional laser measurement technology in dynamic monitoring of mine geological environment","authors":"Yi Wang, Wei Sun, Peiyong He, Wen Qiao","doi":"10.1117/12.2667945","DOIUrl":"https://doi.org/10.1117/12.2667945","url":null,"abstract":"In order to ensure that China's mineral industry can achieve higher benefits and improve work efficiency, mineral enterprises should make dynamic detection and mapping of the geological conditions of mines in time, and take the accurate mapping results as the actual basis in the mining process. Therefore, it is necessary to monitor the complex mine environment, effectively deal with emergencies under the concept of sustainable development strategy, and ensure mine production safety and ecological balance.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"256 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115787390","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 the field of industrial automation, accurate acquisition of object three-dimensional information is beneficial to better product design. Structured light three-dimensional measurement technique has been widely used in industrial inspection and reverse engineering because of its advantages of non-contact and high measurement accuracy. The structured light three-dimensional measurement technique combined with gray code and phase shift method has high efficiency and strong robustness. However, in the process of extract the phase map of the measured objects, there will be misalignment between the wrapped phase and the fringe order. This will lead to the jump error of wrapping phase edge in phase unwrapping process, which will reduce the measurement accuracy. To solve this problem, the fast tripartite phase unwrapping method is proposed in this paper, which can effectively eliminate the phase unwrapping error and significantly improve the computational efficiency. Firstly, the mask image is obtained by threshold segmentation of full-bright images using OTSU method. Subsequently, phase unwrapping is carried out under the guidance of gray code coding sequence, and the absolute phase value of the target is obtained. In the process of phase unwrapping, the mask image is used as the guide to improve the phase decoding efficiency, and tripartite phase unwrapping method is used to eliminate the phase unwrapping error. Experimental results show that this algorithm eliminates the edge jump error and improves the efficiency of normal gray code phase unwrapping method.
{"title":"Research on method of avoiding phase unwrapping error in 3D measurement of gray code","authors":"JiLong Xia, Xiaofei Wang, H. Fan","doi":"10.1117/12.2667751","DOIUrl":"https://doi.org/10.1117/12.2667751","url":null,"abstract":"In the field of industrial automation, accurate acquisition of object three-dimensional information is beneficial to better product design. Structured light three-dimensional measurement technique has been widely used in industrial inspection and reverse engineering because of its advantages of non-contact and high measurement accuracy. The structured light three-dimensional measurement technique combined with gray code and phase shift method has high efficiency and strong robustness. However, in the process of extract the phase map of the measured objects, there will be misalignment between the wrapped phase and the fringe order. This will lead to the jump error of wrapping phase edge in phase unwrapping process, which will reduce the measurement accuracy. To solve this problem, the fast tripartite phase unwrapping method is proposed in this paper, which can effectively eliminate the phase unwrapping error and significantly improve the computational efficiency. Firstly, the mask image is obtained by threshold segmentation of full-bright images using OTSU method. Subsequently, phase unwrapping is carried out under the guidance of gray code coding sequence, and the absolute phase value of the target is obtained. In the process of phase unwrapping, the mask image is used as the guide to improve the phase decoding efficiency, and tripartite phase unwrapping method is used to eliminate the phase unwrapping error. Experimental results show that this algorithm eliminates the edge jump error and improves the efficiency of normal gray code phase unwrapping method.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115296801","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}
Kun Wang, Lianke Xie, Yidan Zhu, Hongbing Su, Dandan Dou, Guoying Zhang
In order to analyze the noise spectrum of converter substation and control the occupational exposure noise of operators at an acceptable level, this paper makes field measurement and spectrum analysis of occupational exposure noise of converter transformers, converter valve halls, AC filters and other operators in converter substations with different voltage levels. The results show that the noise energy of converter substation is mainly concentrated in the middle and low frequencies, and the sound pressure level of the line spectrum with even frequency doubling of 50Hz is prominent, and the frequency is concentrated in the frequency range of 100 ~ 1000 Hz. Except that the energy of the valve hall is still high at the high frequency, the sound pressure level of noise in other workplaces almost drops below 50dB when the frequency is higher than 5kHz. Based on this feature, noise control measures are put forward from three aspects: sound source control, sound insulation control and personnel protection.
{"title":"Frequency spectrum analysis and control technology analysis of converter noise in substation","authors":"Kun Wang, Lianke Xie, Yidan Zhu, Hongbing Su, Dandan Dou, Guoying Zhang","doi":"10.1117/12.2667921","DOIUrl":"https://doi.org/10.1117/12.2667921","url":null,"abstract":"In order to analyze the noise spectrum of converter substation and control the occupational exposure noise of operators at an acceptable level, this paper makes field measurement and spectrum analysis of occupational exposure noise of converter transformers, converter valve halls, AC filters and other operators in converter substations with different voltage levels. The results show that the noise energy of converter substation is mainly concentrated in the middle and low frequencies, and the sound pressure level of the line spectrum with even frequency doubling of 50Hz is prominent, and the frequency is concentrated in the frequency range of 100 ~ 1000 Hz. Except that the energy of the valve hall is still high at the high frequency, the sound pressure level of noise in other workplaces almost drops below 50dB when the frequency is higher than 5kHz. Based on this feature, noise control measures are put forward from three aspects: sound source control, sound insulation control and personnel protection.","PeriodicalId":227067,"journal":{"name":"International Conference on Precision Instruments and Optical Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129453066","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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