Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701835
J. Young, M. Casey, D. Newport
In positron emission tomographs (PET), the ratio of time coincident events to single events is less than one out of twenty. A significant reduction in the bandwidth necessary to transmit the coincident events to a histogramming circuit can be achieved by using this fact. Since the coincident events occur randomly, there is a finite chance that no coincident events occur within a clock cycle. We present an architecture that uses the vacant clock cycles to transmit any extra events that occur during non-zero clock cycles. An analysis of this architecture along with a Monte Carlo simulation show that a reduction in complexity can be achieved while maintaining virtually no event loss at coincidence rates near channel saturation. This architecture has been implemented in a VLSI gate array and is presented in the paper.
{"title":"Optimum Bandwidth Usage In Digital Coincidence Detection For PET","authors":"J. Young, M. Casey, D. Newport","doi":"10.1109/NSSMIC.1993.701835","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701835","url":null,"abstract":"In positron emission tomographs (PET), the ratio of time coincident events to single events is less than one out of twenty. A significant reduction in the bandwidth necessary to transmit the coincident events to a histogramming circuit can be achieved by using this fact. Since the coincident events occur randomly, there is a finite chance that no coincident events occur within a clock cycle. We present an architecture that uses the vacant clock cycles to transmit any extra events that occur during non-zero clock cycles. An analysis of this architecture along with a Monte Carlo simulation show that a reduction in complexity can be achieved while maintaining virtually no event loss at coincidence rates near channel saturation. This architecture has been implemented in a VLSI gate array and is presented in the paper.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116989974","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701802
L. P. Gradin, N. Burstein
Nuclear plants develop a surveillance and maintenance program that relates to assuring the continuing adequacy of important plant equipment. This is especially true regarding nuclear safety-related equipment which is considered to be part of the "Safety-Related structures, systems, or components that are relied upon to remain functional during and following design basis events to ensure the integrity of the reactor coolant pressure boundary, the capability to shut down the reactor and maintain it in a safe shutdown, and the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposure comparable to lOCFR part 100 guidelines" consistent with 10CFR50.65(1). In addition electrical nuclear safety related equipment which may be subject to a harsh environment must be maintained in a state of readiness to perform during the harsh environmental conditions of the nuclear accident. A cost- effective surveillance and maintenance program should assure that equipment adequacy to perform or remain operable is retained. This paper describes the criteria used for selection of a Non-Intrusive Condition Evaluation (NICE) system by Motor Current Signature Analysis (MCSA) to assess selected conditions of relatively inaccessible incontainment motors during normal operation. It also describes the successful results from use of such a system.
{"title":"Assessment Of Containment Fan Cooler Degradation By Motor Current Signature Analysis","authors":"L. P. Gradin, N. Burstein","doi":"10.1109/NSSMIC.1993.701802","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701802","url":null,"abstract":"Nuclear plants develop a surveillance and maintenance program that relates to assuring the continuing adequacy of important plant equipment. This is especially true regarding nuclear safety-related equipment which is considered to be part of the \"Safety-Related structures, systems, or components that are relied upon to remain functional during and following design basis events to ensure the integrity of the reactor coolant pressure boundary, the capability to shut down the reactor and maintain it in a safe shutdown, and the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposure comparable to lOCFR part 100 guidelines\" consistent with 10CFR50.65(1). In addition electrical nuclear safety related equipment which may be subject to a harsh environment must be maintained in a state of readiness to perform during the harsh environmental conditions of the nuclear accident. A cost- effective surveillance and maintenance program should assure that equipment adequacy to perform or remain operable is retained. This paper describes the criteria used for selection of a Non-Intrusive Condition Evaluation (NICE) system by Motor Current Signature Analysis (MCSA) to assess selected conditions of relatively inaccessible incontainment motors during normal operation. It also describes the successful results from use of such a system.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116272361","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701777
L. P. Gradin, P. Jaskolowski
Repaired Motors for Nuclear Power Plants require that: (1) adequate controls and traceability exist for motor repair, (2) operability is not degraded by the repair, (3) special nuclear capable materials are used when required, (4) appropriate consideration be given to the driven load requirements, and (5) s ecial adequacy and performance testin is compreted demonstrating suitability, especiah y for Nuclear Safety Related service subsequent to repair. An evolving consensus of “good practice” is developing based on industr experience feedback, guidance from IEEE standards development, EPRI research, and the Electric Apparatus Service Association practices. Adequacy re uires careful attention to Commercial %rade Item Dedication, Qualification, and Quality Processes. This paper presents various considerations for motor inspection, assessment, material procurement, documentation, repair, determination of critical characteristics, and testin to allow retention or enhancement of original fesign qualification and demonstrated capability for the motor being repaired.
{"title":"Assuring Adequacy Of Motor Repairs For Nuclear Power Plants","authors":"L. P. Gradin, P. Jaskolowski","doi":"10.1109/NSSMIC.1993.701777","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701777","url":null,"abstract":"Repaired Motors for Nuclear Power Plants require that: (1) adequate controls and traceability exist for motor repair, (2) operability is not degraded by the repair, (3) special nuclear capable materials are used when required, (4) appropriate consideration be given to the driven load requirements, and (5) s ecial adequacy and performance testin is compreted demonstrating suitability, especiah y for Nuclear Safety Related service subsequent to repair. An evolving consensus of “good practice” is developing based on industr experience feedback, guidance from IEEE standards development, EPRI research, and the Electric Apparatus Service Association practices. Adequacy re uires careful attention to Commercial %rade Item Dedication, Qualification, and Quality Processes. This paper presents various considerations for motor inspection, assessment, material procurement, documentation, repair, determination of critical characteristics, and testin to allow retention or enhancement of original fesign qualification and demonstrated capability for the motor being repaired.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"201 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126026696","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701698
M. Salomon, J. Armitage, M. Dixit, W. Faszer, D. Lam, G. Oakha
We have measured several properties of gas microstrip detectors built with Tedlar substrates and aluminum traces. We used several gases including argon/ethane mixtures as well as CF/sub 4//isobutane. Gain and timing properties were measured, but our principal concern in this paper was the long term stability of these types of detectors. It was found that gain changes and discharges were the main problems. We could solve both by passivating the prints with a thin metal oxide layer. >
{"title":"Some Properties Of Gas Microstrip Detectors Made On Tedlar Substrates And Operating With CF/sub 4//Isobutane Gas","authors":"M. Salomon, J. Armitage, M. Dixit, W. Faszer, D. Lam, G. Oakha","doi":"10.1109/NSSMIC.1993.701698","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701698","url":null,"abstract":"We have measured several properties of gas microstrip detectors built with Tedlar substrates and aluminum traces. We used several gases including argon/ethane mixtures as well as CF/sub 4//isobutane. Gain and timing properties were measured, but our principal concern in this paper was the long term stability of these types of detectors. It was found that gain changes and discharges were the main problems. We could solve both by passivating the prints with a thin metal oxide layer. >","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125727511","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701857
C. Ahn, I. Kim, S. Han
The international standard for digital compression and coding of continuous-tone still images known as JPEG(Joint Photographic Experts Groups) standard is implemented and tested for medical image archiving and communication. For a series of head sections of magnetic resonance images, compression ratio of about 10 is obtained without noticeable image degradation. Compared to existing full-frame bit-allocation technique, the JPEG standard achieves higher compression with higher signal-tc-noise ratio. The reconstructed images by the JPEG standard slao show much less Gibb’s artifact. Feature of the progressive image build-up of the JPEG progressive coding appears useful in medical image archiving and communication where fast search of image from huge image data base and urgent diagnosis from remote site are often in need.
{"title":"Medical Image Compression Using JPEG Progressive Coding","authors":"C. Ahn, I. Kim, S. Han","doi":"10.1109/NSSMIC.1993.701857","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701857","url":null,"abstract":"The international standard for digital compression and coding of continuous-tone still images known as JPEG(Joint Photographic Experts Groups) standard is implemented and tested for medical image archiving and communication. For a series of head sections of magnetic resonance images, compression ratio of about 10 is obtained without noticeable image degradation. Compared to existing full-frame bit-allocation technique, the JPEG standard achieves higher compression with higher signal-tc-noise ratio. The reconstructed images by the JPEG standard slao show much less Gibb’s artifact. Feature of the progressive image build-up of the JPEG progressive coding appears useful in medical image archiving and communication where fast search of image from huge image data base and urgent diagnosis from remote site are often in need.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127824556","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.373545
J. Gordon, R. Farrell, K. Daley, C. Oakes
Radioactive labeling of proteins is a very important technique used in biomedical research to identify, isolate, and investigate the expression and properties of proteins in biological systems. In such procedures, the preferred radiolabel is often tritium. Presently, binding assays involving tritium are carried out using inconvenient and expensive techniques which rely on the use of scintillation fluid counting systems. This traditional method involves both time-consuming laboratory protocols and the generation of substantial quantities of radioactive and chemical waste. The authors have developed a novel technology to measure the tritium content of biological specimens that does not rely on scintillation fluids. The tritiated samples can be positioned directly under a large area, monolithic array of specially prepared avalanche photodiodes which record the tritium activity distribution at each point within the field of view of the array. The 1 mm/sup 2/ sensing elements exhibit an intrinsic tritium beta detection efficiency of 27% with high gain uniformity and very low cross talk.<>
{"title":"Solid state tritium detector for biomedical applications","authors":"J. Gordon, R. Farrell, K. Daley, C. Oakes","doi":"10.1109/NSSMIC.1993.373545","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.373545","url":null,"abstract":"Radioactive labeling of proteins is a very important technique used in biomedical research to identify, isolate, and investigate the expression and properties of proteins in biological systems. In such procedures, the preferred radiolabel is often tritium. Presently, binding assays involving tritium are carried out using inconvenient and expensive techniques which rely on the use of scintillation fluid counting systems. This traditional method involves both time-consuming laboratory protocols and the generation of substantial quantities of radioactive and chemical waste. The authors have developed a novel technology to measure the tritium content of biological specimens that does not rely on scintillation fluids. The tritiated samples can be positioned directly under a large area, monolithic array of specially prepared avalanche photodiodes which record the tritium activity distribution at each point within the field of view of the array. The 1 mm/sup 2/ sensing elements exhibit an intrinsic tritium beta detection efficiency of 27% with high gain uniformity and very low cross talk.<<ETX>>","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"C-20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126778075","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701659
D. Kawall, Z. Meziani, R. Gearhart, E. Hughes, M. Spengos
We present the design and performance of a set of large volume gas threshold Cerenkov detectors recently used in the k e d target experiment E142 at SLAC*. The detectors used a 4.0 meter effective length of nitrogen at 3.0 psia to achieve a pion threshold of 13.0 GeV/c. A five inch photomultiplier coated with pterphenyl wavelength shifter was used to detect an average of 7.0 photoelectrons per electron scattered through the detector, resulting in a 99% detection efficiency and No = 150 cm-’.
{"title":"Performance Of A Set Of Large Volume Threshold Cherenkov Detectors","authors":"D. Kawall, Z. Meziani, R. Gearhart, E. Hughes, M. Spengos","doi":"10.1109/NSSMIC.1993.701659","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701659","url":null,"abstract":"We present the design and performance of a set of large volume gas threshold Cerenkov detectors recently used in the k e d target experiment E142 at SLAC*. The detectors used a 4.0 meter effective length of nitrogen at 3.0 psia to achieve a pion threshold of 13.0 GeV/c. A five inch photomultiplier coated with pterphenyl wavelength shifter was used to detect an average of 7.0 photoelectrons per electron scattered through the detector, resulting in a 99% detection efficiency and No = 150 cm-’.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"29 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123218072","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.373555
S. Glick, B. C. Penney, C. Byrne
Reconstructed SPECT images suffer from decreased image quality due to photon attenuation within the patient and distance-dependent blurring introduced by the collimated gamma camera. Several iterative reconstruction algorithms have been proposed to compensate for these degradations, as well as to suppress noise. These methods require the use of a realistic projector and back-projector pair which can accurately model the physics of photon transport. Here, the authors describe a projector/backprojector pair which accurately models both photon attenuation and the distance-dependent detector response, and provides a substantial decrease in computational complexity over previous methods. The computational savings are obtained by using the frequency distance principle (FDP) to incorporate distance-dependent blurring into the projector/back-projector pair. Since this procedure can be implemented using FFT methods, distance-dependent blurring can be modeled with a substantial reduction in the number of computations required. Simulation studies using a paint source object and the Hoffman bit-map brain phantom have shown that use of the FDP based projector-backprojector pair can reduce the computation time required for iterative reconstruction, with minimal loss of accuracy.<>
{"title":"A fast projector backprojector pair for use in iterative reconstruction of SPECT images","authors":"S. Glick, B. C. Penney, C. Byrne","doi":"10.1109/NSSMIC.1993.373555","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.373555","url":null,"abstract":"Reconstructed SPECT images suffer from decreased image quality due to photon attenuation within the patient and distance-dependent blurring introduced by the collimated gamma camera. Several iterative reconstruction algorithms have been proposed to compensate for these degradations, as well as to suppress noise. These methods require the use of a realistic projector and back-projector pair which can accurately model the physics of photon transport. Here, the authors describe a projector/backprojector pair which accurately models both photon attenuation and the distance-dependent detector response, and provides a substantial decrease in computational complexity over previous methods. The computational savings are obtained by using the frequency distance principle (FDP) to incorporate distance-dependent blurring into the projector/back-projector pair. Since this procedure can be implemented using FFT methods, distance-dependent blurring can be modeled with a substantial reduction in the number of computations required. Simulation studies using a paint source object and the Hoffman bit-map brain phantom have shown that use of the FDP based projector-backprojector pair can reduce the computation time required for iterative reconstruction, with minimal loss of accuracy.<<ETX>>","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123574126","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.373544
Zhe Wu, A. Maudsley, M. Weiner
A fully automated spectral analysis method is proposed. This is used in combination with several additional processing steps to provide totally automated formation of /sup 1/H metabolite images from the magnetic resonance (MR) spectral data of the human brain. The MR images obtained by the new method show great improvement compared with the images obtained by the traditional method. The new method could provide a very promising solution to massive routine processing of magnetic resonance spectral imaging data for clinical and biomedical studies.<>
{"title":"Fully automatic processing of in vivo proton spectra and spectroscopic images","authors":"Zhe Wu, A. Maudsley, M. Weiner","doi":"10.1109/NSSMIC.1993.373544","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.373544","url":null,"abstract":"A fully automated spectral analysis method is proposed. This is used in combination with several additional processing steps to provide totally automated formation of /sup 1/H metabolite images from the magnetic resonance (MR) spectral data of the human brain. The MR images obtained by the new method show great improvement compared with the images obtained by the traditional method. The new method could provide a very promising solution to massive routine processing of magnetic resonance spectral imaging data for clinical and biomedical studies.<<ETX>>","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126462196","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}
Pub Date : 1993-10-31DOI: 10.1109/NSSMIC.1993.701702
T. Pochet, A. Ilie, F. Foulon, B. Equer
This paper is concerned with the characterization of new detectors fabricated from a-Si:H films deposited at high rates through the dilution of SiH/sub 4/ in Helium by PECVD (plasma enhanced chemical vapor deposition) technique. Rates up to ten times (5.5 /spl mu/m/h) that of the standard technique are obtained. We have investigated the electrical characteristics -depletion voltage, residual space charge density- of the helium diluted material and compared them to that of the standard material. Finally, the response of detectors, fabricated from both materials, to 5.5 MeV alpha particles are compared. >
{"title":"Characterization Of New A-Si:H Detectors Fabricated From Amorphous Silicon Deposited At High Rate By Helium Enhanced PECVD","authors":"T. Pochet, A. Ilie, F. Foulon, B. Equer","doi":"10.1109/NSSMIC.1993.701702","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701702","url":null,"abstract":"This paper is concerned with the characterization of new detectors fabricated from a-Si:H films deposited at high rates through the dilution of SiH/sub 4/ in Helium by PECVD (plasma enhanced chemical vapor deposition) technique. Rates up to ten times (5.5 /spl mu/m/h) that of the standard technique are obtained. We have investigated the electrical characteristics -depletion voltage, residual space charge density- of the helium diluted material and compared them to that of the standard material. Finally, the response of detectors, fabricated from both materials, to 5.5 MeV alpha particles are compared. >","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120936998","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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