Pub Date : 2005-10-03DOI: 10.1109/ISEMC.2005.1513570
D. Carpenter
Of all the probability distributions considered during the calculation of measurement uncertainty, the U-shaped distribution is generally least familiar to the typical EMC engineer. A previous paper (Carpenter, E., 2003) attempted to demystify the distribution by demonstrating that it occurs naturally when considering the voltage standing wave (VSW) amplitude generated along the length of a semi-infinite cable by impedance mismatch at its termination. This paper seeks to continue the demystification by presenting additional background unlikely to be familiar to the typical EMC engineer. Specifically, the origin of the 1//spl radic/2 normalisation factor, used to determine the standard uncertainty contribution due to mismatch, is presented, as is the relationship between the U-shaped distribution and the beta and gamma distributions.
{"title":"A further demystification of the U-shaped probability distribution","authors":"D. Carpenter","doi":"10.1109/ISEMC.2005.1513570","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513570","url":null,"abstract":"Of all the probability distributions considered during the calculation of measurement uncertainty, the U-shaped distribution is generally least familiar to the typical EMC engineer. A previous paper (Carpenter, E., 2003) attempted to demystify the distribution by demonstrating that it occurs naturally when considering the voltage standing wave (VSW) amplitude generated along the length of a semi-infinite cable by impedance mismatch at its termination. This paper seeks to continue the demystification by presenting additional background unlikely to be familiar to the typical EMC engineer. Specifically, the origin of the 1//spl radic/2 normalisation factor, used to determine the standard uncertainty contribution due to mismatch, is presented, as is the relationship between the U-shaped distribution and the beta and gamma distributions.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"73 1","pages":"519-524 Vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79090009","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513619
G. Thomason, V. Ivanov
Dell has developed a method for evaluating the immunity of an electronic device (e.g., portable computer, personnel data assistant [PDA]1 etc) when placed in close proximity to electro-magnetic fields generated by wireless devices. In particular, wireless devices which operate in the global system for mobile communications (GSM) bands. For example, PC cards, cell phones, and cellular walkie talkies. The purpose of this study was to; 1) define an engineering test for evaluating a system's immunity to radiated fields generated by a wireless device and 2) develop a methodology for analyzing issues at the board level and identifying root cause.
{"title":"Method for evaluating system immunity to wireless GSM devices","authors":"G. Thomason, V. Ivanov","doi":"10.1109/ISEMC.2005.1513619","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513619","url":null,"abstract":"Dell has developed a method for evaluating the immunity of an electronic device (e.g., portable computer, personnel data assistant [PDA]1 etc) when placed in close proximity to electro-magnetic fields generated by wireless devices. In particular, wireless devices which operate in the global system for mobile communications (GSM) bands. For example, PC cards, cell phones, and cellular walkie talkies. The purpose of this study was to; 1) define an engineering test for evaluating a system's immunity to radiated fields generated by a wireless device and 2) develop a methodology for analyzing issues at the board level and identifying root cause.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"42 1","pages":"726-729 Vol. 3"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76952033","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513479
Hsing-Feng Chen, Ken-Huang Lin, Cheng-Chang Chen, Y. Tang
This study proposed a modified phase center and pattern matching (PCPM) method to reduce antenna factor (AF) variations of Bilog between different geometries of standard site method (SSM). For frequencies below 300 MHz, mutual coupling may have an effect on the results of original PCPM, thereby enlarging AF variations of Bilog. Therefore, a modified PCPM was applied with the results showing that AF variations of a Bilog can be reduced by 1.8 dB after modification
提出了一种改进的相位中心和方向匹配(PCPM)方法，以减小标准站点法(SSM)不同几何形状之间的天线因子(AF)变化。对于低于300 MHz的频率，相互耦合可能对原始PCPM的结果产生影响，从而扩大了Bilog的AF变化。因此，应用改进的PCPM，结果表明，修改后的biog的AF变化可减少1.8 dB
{"title":"A modified phase center and pattern matching method to reduce the geometry dependence of bilog calibration in standard site method","authors":"Hsing-Feng Chen, Ken-Huang Lin, Cheng-Chang Chen, Y. Tang","doi":"10.1109/ISEMC.2005.1513479","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513479","url":null,"abstract":"This study proposed a modified phase center and pattern matching (PCPM) method to reduce antenna factor (AF) variations of Bilog between different geometries of standard site method (SSM). For frequencies below 300 MHz, mutual coupling may have an effect on the results of original PCPM, thereby enlarging AF variations of Bilog. Therefore, a modified PCPM was applied with the results showing that AF variations of a Bilog can be reduced by 1.8 dB after modification","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"114 1","pages":"90-92"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76151629","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513498
J. P. Donohoe, Jun Xu, C. Pittman
Shielding effectiveness measurements have been performed on a vapor grown carbon fiber (VGCF)/vinyl ester (VE) composite material over a frequency range of 10 MHz to 1 GHz using a dual TEM (DTEM) cell along with a vector network analyzer. A VGCF/VE composite sample containing 15% carbon fiber by weight is utilized in the measurements. The electric and magnetic shielding effectiveness of the VGCF/VE composite are measured in the form of electric and magnetic field insertion losses. The shielding effectiveness results for the VGCF/VE composite are shown to exhibit significant variation with regard to the placement of the composite sample in the DTEM cell. The electric field insertion loss of the VGCF/VE composite is found to be more highly variable from measurement to measurement than the magnetic field insertion loss.
{"title":"Variability of dual TEM cell shielding effectiveness measurements for vapor grown carbon nanofiber/vinyl ester composites","authors":"J. P. Donohoe, Jun Xu, C. Pittman","doi":"10.1109/ISEMC.2005.1513498","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513498","url":null,"abstract":"Shielding effectiveness measurements have been performed on a vapor grown carbon fiber (VGCF)/vinyl ester (VE) composite material over a frequency range of 10 MHz to 1 GHz using a dual TEM (DTEM) cell along with a vector network analyzer. A VGCF/VE composite sample containing 15% carbon fiber by weight is utilized in the measurements. The electric and magnetic shielding effectiveness of the VGCF/VE composite are measured in the form of electric and magnetic field insertion losses. The shielding effectiveness results for the VGCF/VE composite are shown to exhibit significant variation with regard to the placement of the composite sample in the DTEM cell. The electric field insertion loss of the VGCF/VE composite is found to be more highly variable from measurement to measurement than the magnetic field insertion loss.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"23 2 1","pages":"190-194 Vol. 1"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72695635","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513577
Yi Huang, J. Zhang, Ping Liu
In a reverberation chamber, the internal electromagnetic fields are perturbed by a metallic stirrer and thus the stirrer has a significant impact on the chamber performance. How to judge the effectiveness of a stirrer has been a question for years, in this paper, we propose a novel method, based on the principle of eigenmodes perturbation, to examine the effectiveness of a stirrer. Comparing three types of stirrers, we find that a stirrer with bending and in an irregular shape is the most effective, and it has the ability to shift the eigenfrequencies of the chamber most significantly. A new approach to examine the stirrer effectiveness is performed by using spherical chambers. Analysis of the field uniformity in a practical rectangular chamber is conducted to justify the approach
{"title":"A novel method to examine the effectiveness of a stirrer","authors":"Yi Huang, J. Zhang, Ping Liu","doi":"10.1109/ISEMC.2005.1513577","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513577","url":null,"abstract":"In a reverberation chamber, the internal electromagnetic fields are perturbed by a metallic stirrer and thus the stirrer has a significant impact on the chamber performance. How to judge the effectiveness of a stirrer has been a question for years, in this paper, we propose a novel method, based on the principle of eigenmodes perturbation, to examine the effectiveness of a stirrer. Comparing three types of stirrers, we find that a stirrer with bending and in an irregular shape is the most effective, and it has the ability to shift the eigenfrequencies of the chamber most significantly. A new approach to examine the stirrer effectiveness is performed by using spherical chambers. Analysis of the field uniformity in a practical rectangular chamber is conducted to justify the approach","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"48 1","pages":"556-561"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86500049","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513531
A. Vogt, H. A. Kołodziej, A. E. Sowa
In this paper, the authors analyse the usefulness of a new composite absorbing material which can be used to make two-layer hybrid absorbers incorporating a ferrite base layer, using the method of homogenization and the transmission line approach. The results acquired show the possibility of obtaining a reflectivity in the range -20 dB and better in the frequency-range from around 30 MHz up to several GHz, using a thickness of absorber significantly less than that which is used with current types of absorbers given in this document.
{"title":"Hybrid absorber using new absorbing composites","authors":"A. Vogt, H. A. Kołodziej, A. E. Sowa","doi":"10.1109/ISEMC.2005.1513531","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513531","url":null,"abstract":"In this paper, the authors analyse the usefulness of a new composite absorbing material which can be used to make two-layer hybrid absorbers incorporating a ferrite base layer, using the method of homogenization and the transmission line approach. The results acquired show the possibility of obtaining a reflectivity in the range -20 dB and better in the frequency-range from around 30 MHz up to several GHz, using a thickness of absorber significantly less than that which is used with current types of absorbers given in this document.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"24 1","pages":"315-318 Vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86523425","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513539
N. Pischl
Ethernet transceivers are connected to twisted-pair cables by magnetics, which typically contain pulse transformers, common mode chokes, capacitors and resistors. Voltage waveforms on the transceiver-side of magnetics due to electrostatic discharge to the cable-side pins of an integrated Ethernet connector have been measured. 200 m CAT5 unshielded and shielded twisted-pair cables were used. Effect of proximity of the cable to grounded metal carrier in a cable rack was observed. Three methods of discharge to the connector pins are compared: contact-discharge of an ESD-gun, manual discharge of the cables, and cable-discharge using an automatic setup that employs high-voltage relays. The results can also help standardizing the test procedure.
{"title":"ESD transfer through Ethernet magnetics","authors":"N. Pischl","doi":"10.1109/ISEMC.2005.1513539","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513539","url":null,"abstract":"Ethernet transceivers are connected to twisted-pair cables by magnetics, which typically contain pulse transformers, common mode chokes, capacitors and resistors. Voltage waveforms on the transceiver-side of magnetics due to electrostatic discharge to the cable-side pins of an integrated Ethernet connector have been measured. 200 m CAT5 unshielded and shielded twisted-pair cables were used. Effect of proximity of the cable to grounded metal carrier in a cable rack was observed. Three methods of discharge to the connector pins are compared: contact-discharge of an ESD-gun, manual discharge of the cables, and cable-discharge using an automatic setup that employs high-voltage relays. The results can also help standardizing the test procedure.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"11 1","pages":"356-363 Vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87410838","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513615
G. Antonini, A. Scogna, A. Orlandi, V. Ricchiuti
As digital circuits became faster and more power is involved, direct coupling in multilayer printed circuit boards (PCBs) among power (PWR) planes becomes a major concern for signal integrity (SI) and electromagnetic interference (EMI). Aim of this paper is to show how an electromagnetic wave can propagate between planes and therefore induce noise on the signals crossing the planes' pairs through vias eventually radiate from the edge of the board. More specifically our study focuses on the analysis of the noise which propagates from a power plane to another power plane due to their proximity, named cross-simultaneous switching noise (X-SSN). This effect can be mitigated by a careful analysis of the location of PWR and ground (GND) planes in the board stack-up which avoid the contiguity of two PWR planes. A test board is built and measurements are performed. These measurements are also compared with three dimensional numerical results.
{"title":"Cross-SSN analysis in multilayer printed circuit boards","authors":"G. Antonini, A. Scogna, A. Orlandi, V. Ricchiuti","doi":"10.1109/ISEMC.2005.1513615","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513615","url":null,"abstract":"As digital circuits became faster and more power is involved, direct coupling in multilayer printed circuit boards (PCBs) among power (PWR) planes becomes a major concern for signal integrity (SI) and electromagnetic interference (EMI). Aim of this paper is to show how an electromagnetic wave can propagate between planes and therefore induce noise on the signals crossing the planes' pairs through vias eventually radiate from the edge of the board. More specifically our study focuses on the analysis of the noise which propagates from a power plane to another power plane due to their proximity, named cross-simultaneous switching noise (X-SSN). This effect can be mitigated by a careful analysis of the location of PWR and ground (GND) planes in the board stack-up which avoid the contiguity of two PWR planes. A test board is built and measurements are performed. These measurements are also compared with three dimensional numerical results.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"7 1","pages":"705-710 Vol. 3"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85364253","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513548
D. Warkentin, A. Wang, W. Crunkhorn
Radiated emissions measurements performed in accordance with MIL-STD-461E require the use of a shielded enclosure to prevent measurement contamination by ambient environmental signals. Unfortunately, these metallic enclosures add errors due to resonant effects. A simple test procedure, validated by finite difference time domain modeling, has been developed to characterize the HF response of a shielded enclosure. This procedure was used to improve the accuracy of a typical shielded enclosure while remaining compliant to the requirements of MIL-STD-461E.
{"title":"Shielded enclosure accuracy improvements for MIL-STD-461E radiated emissions measurements","authors":"D. Warkentin, A. Wang, W. Crunkhorn","doi":"10.1109/ISEMC.2005.1513548","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513548","url":null,"abstract":"Radiated emissions measurements performed in accordance with MIL-STD-461E require the use of a shielded enclosure to prevent measurement contamination by ambient environmental signals. Unfortunately, these metallic enclosures add errors due to resonant effects. A simple test procedure, validated by finite difference time domain modeling, has been developed to characterize the HF response of a shielded enclosure. This procedure was used to improve the accuracy of a typical shielded enclosure while remaining compliant to the requirements of MIL-STD-461E.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"79 1","pages":"404-409 Vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85530182","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 : 2005-10-03DOI: 10.1109/ISEMC.2005.1513651
Y. Bayram, J. Volakis, P. Roblin
We propose a hybrid scattering parameter matrix for concurrent on & off board EMI analysis of mixed RF-digital circuits. To start with, we first consider on-board EMI effects on digital circuits, particularly on an inverter to show the vulnerability of digital devices to RF interference and investigate both system and device level upsets due to adjacent EMI sources on printed circuit boards (PCBs). Next, we review port analysis technique to show the applications of S-parameter matrix for on-board EMI/EMC analysis. Subsequently, we extent the port analysis method with hybrid S-parameters to account for external field coupling to RF-digital circuit boards. In this context, we introduce a novel method in the frequency domain to circumvent CPU bottlenecks associated with time domain methods and yields increased accuracy as compared to transmission line theory. To do so, we present additional hybrid S-parameters that establish a link between the existing board ports and external plane wave. Thus, we can handle both on-board and off-board EMI problems simultaneously. The new hybrid S-parameter matrix is easily integrated into circuit solvers such as HSPICE and advanced design system (ADS, Agilent Technologies) and also allows both time domain and harmonic balance simulations of non-linear RF-digital components via broad-band network characterization. The proposed method was validated with full wave solvers and implemented for susceptibility analysis of an inverter, residing inside a metallic box, subject to a strong plane wave.
{"title":"A novel technique for concurrent on & off - board EMI analysis of mixed RF-digital circuits via hybrid scattering patterns","authors":"Y. Bayram, J. Volakis, P. Roblin","doi":"10.1109/ISEMC.2005.1513651","DOIUrl":"https://doi.org/10.1109/ISEMC.2005.1513651","url":null,"abstract":"We propose a hybrid scattering parameter matrix for concurrent on & off board EMI analysis of mixed RF-digital circuits. To start with, we first consider on-board EMI effects on digital circuits, particularly on an inverter to show the vulnerability of digital devices to RF interference and investigate both system and device level upsets due to adjacent EMI sources on printed circuit boards (PCBs). Next, we review port analysis technique to show the applications of S-parameter matrix for on-board EMI/EMC analysis. Subsequently, we extent the port analysis method with hybrid S-parameters to account for external field coupling to RF-digital circuit boards. In this context, we introduce a novel method in the frequency domain to circumvent CPU bottlenecks associated with time domain methods and yields increased accuracy as compared to transmission line theory. To do so, we present additional hybrid S-parameters that establish a link between the existing board ports and external plane wave. Thus, we can handle both on-board and off-board EMI problems simultaneously. The new hybrid S-parameter matrix is easily integrated into circuit solvers such as HSPICE and advanced design system (ADS, Agilent Technologies) and also allows both time domain and harmonic balance simulations of non-linear RF-digital components via broad-band network characterization. The proposed method was validated with full wave solvers and implemented for susceptibility analysis of an inverter, residing inside a metallic box, subject to a strong plane wave.","PeriodicalId":6459,"journal":{"name":"2005 International Symposium on Electromagnetic Compatibility, 2005. EMC 2005.","volume":"22 19 1","pages":"888-893 Vol. 3"},"PeriodicalIF":0.0,"publicationDate":"2005-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89638314","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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