Pub Date : 1996-08-19DOI: 10.1109/ISEMC.1996.561419
Ya-ping Du, J. Burnett
Magnetic field shielding of cylindrical shields has been studied for a long time, and analytical solution has been derived at power-frequency. This paper, based on previous work, presents an analysis of the shielding principles of a linear cylindrical shield at power-frequency. The shielding principles are developed from simplified shielding formulas under a single-shell and inside-source configuration. Partition of parameter space is introduced, and four regions (linear induced-current, nonlinear induced-current, flux-shunting and induced-current/flux-shunting shielding) are identified geometrically. It reveals the inherent relationship between the shield parameters and shielding effectiveness. A sensitivity study of the shield parameters is conducted too. It discloses the inherent patterns of the parameter impact on the shielding effectiveness. Convenient design curves are presented in the 2D space. These shielding principles and design curves will alleviate the shielding design burden.
{"title":"Magnetic shielding principles of linear cylindrical shield at power-frequency","authors":"Ya-ping Du, J. Burnett","doi":"10.1109/ISEMC.1996.561419","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561419","url":null,"abstract":"Magnetic field shielding of cylindrical shields has been studied for a long time, and analytical solution has been derived at power-frequency. This paper, based on previous work, presents an analysis of the shielding principles of a linear cylindrical shield at power-frequency. The shielding principles are developed from simplified shielding formulas under a single-shell and inside-source configuration. Partition of parameter space is introduced, and four regions (linear induced-current, nonlinear induced-current, flux-shunting and induced-current/flux-shunting shielding) are identified geometrically. It reveals the inherent relationship between the shield parameters and shielding effectiveness. A sensitivity study of the shield parameters is conducted too. It discloses the inherent patterns of the parameter impact on the shielding effectiveness. Convenient design curves are presented in the 2D space. These shielding principles and design curves will alleviate the shielding design burden.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"460 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134063898","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561267
W. Schaefer
Preliminary field strength measurements, also known as prescans, are an integral part of most radiated EMI measurements and serve a number of different purposes. In almost all applications, these type of tests are used to quickly obtain information about the frequency spectrum emitted by the equipment under test (EUT). In order to minimize measurement time, peak detection is usually used instead of quasi-peak or average detection which is called out in most commercial EMI regulations. A measurement system consisting of a swept EMI receiver with a real-time display, dedicated control software, and necessary accessories is best suited for this task. It rapidly acquires spectral information, provides both graphical and tabular representation of test results and gives an insight to characteristics of emissions from the EUT. Achieving the highest measurement speed is one of the most important goals when executing prescans. However, there are tradeoffs to be made which might affect frequency uncertainty, receiver display frequency resolution, display detection mode, antenna tower and turntable movement. This paper discusses the significance of these test parameters for prescan and their impact on measurement time and efficiency.
{"title":"Measurement parameter evaluation for prescans as part of radiated EMI measurements","authors":"W. Schaefer","doi":"10.1109/ISEMC.1996.561267","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561267","url":null,"abstract":"Preliminary field strength measurements, also known as prescans, are an integral part of most radiated EMI measurements and serve a number of different purposes. In almost all applications, these type of tests are used to quickly obtain information about the frequency spectrum emitted by the equipment under test (EUT). In order to minimize measurement time, peak detection is usually used instead of quasi-peak or average detection which is called out in most commercial EMI regulations. A measurement system consisting of a swept EMI receiver with a real-time display, dedicated control software, and necessary accessories is best suited for this task. It rapidly acquires spectral information, provides both graphical and tabular representation of test results and gives an insight to characteristics of emissions from the EUT. Achieving the highest measurement speed is one of the most important goals when executing prescans. However, there are tradeoffs to be made which might affect frequency uncertainty, receiver display frequency resolution, display detection mode, antenna tower and turntable movement. This paper discusses the significance of these test parameters for prescan and their impact on measurement time and efficiency.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124320018","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561249
M. Ju, M. Kriege
This is an attempt to model the cable connecting the mother board of a notebook computer to its flat panel display as a finite length dipole. The goal is to generate a first order approximation to prediction the electromagnetic emission.
{"title":"Prediction of electromagnetic emissions from the cable connecting the notebook computer's mother board to its flat panel display","authors":"M. Ju, M. Kriege","doi":"10.1109/ISEMC.1996.561249","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561249","url":null,"abstract":"This is an attempt to model the cable connecting the mother board of a notebook computer to its flat panel display as a finite length dipole. The goal is to generate a first order approximation to prediction the electromagnetic emission.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114837318","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561224
C.E. Goldblum, D. Lane, J. Press, L. Rayadurga, L. Cohen
Mode-stirred (tuned reverberating) chambers are used for performing EMC measurements. These chambers have several advantages over traditional EMC test facilities. These advantages include the ability to simulate high intensity radiated field (HIRF) levels by using low power amplifiers to produce a statistically isotropic electromagnetic environment. The major disadvantage of the mode-stirred chambers has been the inability to produce an electromagnetic environment near the cutoff frequency of the chamber. Typically, a mode-stirred chamber begins to operate at six times the cutoff frequency or approximately 200 MHz for an average-sized chamber. This limitation has a detrimental impact on electronic equipment assessment within the high frequency (HF) spectrum (2-30 MHz) where a vast majority of electromagnetic interference (EMI) events occur. This paper describes a unique chamber which combines the mode-stirred technique with a method which enables test personnel to perform HIRF testing into the HF spectrum. The Advanced Technology Chamber (ATC) can be used as a standard mode-stirred chamber above 200 MHz and HIRF testing can be continued into the HF spectrum without reinstalling the equipment under test into a different test cell. HF susceptibility testing is usually performed on subsystems utilizing the test techniques described in MIL-SID-462D, Test Method RS103. The wave impedance associated with a parallel plate antenna is 377 ohms. This impedance has little relevance to the wave impedance of an environment containing HF transmitting antennas located within 100 meters of electronic equipment. This environment is of particular interest to the US Navy with its extremely harsh HF topside EM environments. The major advantage of the ATC over parallel plate antennas and hybrid chambers is the ability to produce a true HF wave impedance. The majority of HF disruptions occur close (with respect to the electrical wavelength) to the HF source. Since the wave mode is not TEM in the near field of the antenna, the present plane-wave test techniques can lead to erroneous results.
{"title":"Evanescent modes in a unique mode-stirred chamber the Advanced Technology Chamber (ATC)-design, construction, operation and data","authors":"C.E. Goldblum, D. Lane, J. Press, L. Rayadurga, L. Cohen","doi":"10.1109/ISEMC.1996.561224","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561224","url":null,"abstract":"Mode-stirred (tuned reverberating) chambers are used for performing EMC measurements. These chambers have several advantages over traditional EMC test facilities. These advantages include the ability to simulate high intensity radiated field (HIRF) levels by using low power amplifiers to produce a statistically isotropic electromagnetic environment. The major disadvantage of the mode-stirred chambers has been the inability to produce an electromagnetic environment near the cutoff frequency of the chamber. Typically, a mode-stirred chamber begins to operate at six times the cutoff frequency or approximately 200 MHz for an average-sized chamber. This limitation has a detrimental impact on electronic equipment assessment within the high frequency (HF) spectrum (2-30 MHz) where a vast majority of electromagnetic interference (EMI) events occur. This paper describes a unique chamber which combines the mode-stirred technique with a method which enables test personnel to perform HIRF testing into the HF spectrum. The Advanced Technology Chamber (ATC) can be used as a standard mode-stirred chamber above 200 MHz and HIRF testing can be continued into the HF spectrum without reinstalling the equipment under test into a different test cell. HF susceptibility testing is usually performed on subsystems utilizing the test techniques described in MIL-SID-462D, Test Method RS103. The wave impedance associated with a parallel plate antenna is 377 ohms. This impedance has little relevance to the wave impedance of an environment containing HF transmitting antennas located within 100 meters of electronic equipment. This environment is of particular interest to the US Navy with its extremely harsh HF topside EM environments. The major advantage of the ATC over parallel plate antennas and hybrid chambers is the ability to produce a true HF wave impedance. The majority of HF disruptions occur close (with respect to the electrical wavelength) to the HF source. Since the wave mode is not TEM in the near field of the antenna, the present plane-wave test techniques can lead to erroneous results.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134533345","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561190
J. Knapp, A. Wall
Telecommunications equipment and certain electronic products require approval by the Federal Communications Commission (FCC) before they may be imported and marketed in the United States. There is growing worldwide interest in streamlining equipment approval processes for a number of reasons. The FCC has established an equipment authorization program to ensure that telecommunications and electronic products meet standards that are designed to control radio frequency interference. This paper describes the current FCC equipment authorization requirements and the forces at work seeking to streamline equipment approval processes. Special attention is devoted to international developments. The paper goes on to discuss a major FCC action to deregulate the equipment authorization process for personal computer equipment, that is perhaps a first step towards an equipment approval process that will be consistent with these international developments.
{"title":"Streamlining the FCC equipment authorization process in response to changing global markets","authors":"J. Knapp, A. Wall","doi":"10.1109/ISEMC.1996.561190","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561190","url":null,"abstract":"Telecommunications equipment and certain electronic products require approval by the Federal Communications Commission (FCC) before they may be imported and marketed in the United States. There is growing worldwide interest in streamlining equipment approval processes for a number of reasons. The FCC has established an equipment authorization program to ensure that telecommunications and electronic products meet standards that are designed to control radio frequency interference. This paper describes the current FCC equipment authorization requirements and the forces at work seeking to streamline equipment approval processes. Special attention is devoted to international developments. The paper goes on to discuss a major FCC action to deregulate the equipment authorization process for personal computer equipment, that is perhaps a first step towards an equipment approval process that will be consistent with these international developments.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124830823","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561256
P. Kistenmacher, A. Schwab
This paper presents a two dimensional analytical solution for electromagnetic shielding problems at frequencies below resonances. The application of the method to three dimensional shields yields good approximations, except for errors nearby edges which are not parallel to the magnetic field. The solution is valid for enclosures of arbitrary shape with any given combination of materials and wall thicknesses. Considering skin effects, the shielding effectiveness is derived by solving the Helmholtz equation for individual parts of the wall with different thicknesses and materials. The solution for the total shield is then found by applying Faraday's law in integral form. Three cases are discussed: heterogeneous enclosures consisting of several wall sections with different materials and wall thicknesses, coated, laminated and nested shields and multi-cavity enclosures. Different examples of combinations of non-magnetic and magnetic materials are discussed in detail. Finally, the potential of saving material and weight by using multiple shields is investigated.
{"title":"Low-frequency shielding effectiveness of inhomogeneous enclosures","authors":"P. Kistenmacher, A. Schwab","doi":"10.1109/ISEMC.1996.561256","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561256","url":null,"abstract":"This paper presents a two dimensional analytical solution for electromagnetic shielding problems at frequencies below resonances. The application of the method to three dimensional shields yields good approximations, except for errors nearby edges which are not parallel to the magnetic field. The solution is valid for enclosures of arbitrary shape with any given combination of materials and wall thicknesses. Considering skin effects, the shielding effectiveness is derived by solving the Helmholtz equation for individual parts of the wall with different thicknesses and materials. The solution for the total shield is then found by applying Faraday's law in integral form. Three cases are discussed: heterogeneous enclosures consisting of several wall sections with different materials and wall thicknesses, coated, laminated and nested shields and multi-cavity enclosures. Different examples of combinations of non-magnetic and magnetic materials are discussed in detail. Finally, the potential of saving material and weight by using multiple shields is investigated.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130333442","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561272
W. Croisant, C. A. Feickert, M. McInerney
Previously, an analytical procedure was developed to characterize the nonlinear electric field transients induced at the inner surface of long, thin-walled, cylindrical, electrically conductive, ferromagnetic shields by short-duration, surface current pulses directed axially along the outer surface. The analytical procedure uses mathematical analysis supplemented with numerical calculations. Previous papers emphasized the mathematical aspects of the problem. This paper considers the computational aspects. Some practical aspects associated with the implementation of a finite difference time-domain (FDTD) formulation are discussed. The effects of spatial and time increments on numerical results are investigated. A method for estimating the residual error in benchmark calculations is proposed and demonstrated, and results of example calculations are presented.
{"title":"Computational aspects of a nonlinear problem involving electromagnetic transients in ferromagnetic shields","authors":"W. Croisant, C. A. Feickert, M. McInerney","doi":"10.1109/ISEMC.1996.561272","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561272","url":null,"abstract":"Previously, an analytical procedure was developed to characterize the nonlinear electric field transients induced at the inner surface of long, thin-walled, cylindrical, electrically conductive, ferromagnetic shields by short-duration, surface current pulses directed axially along the outer surface. The analytical procedure uses mathematical analysis supplemented with numerical calculations. Previous papers emphasized the mathematical aspects of the problem. This paper considers the computational aspects. Some practical aspects associated with the implementation of a finite difference time-domain (FDTD) formulation are discussed. The effects of spatial and time increments on numerical results are investigated. A method for estimating the residual error in benchmark calculations is proposed and demonstrated, and results of example calculations are presented.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121677335","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561209
S. Celozzi, M. D'amore
The analysis of shielding performance of ferromagnetic cylindrical cans is presented. The near field loop source is described introducing wave impedances which depend upon the orientation of the source. Hysteresis is taken into account accurately by means of a nonlinear implicit differential equation. The time domain solution procedure is based on the finite element time domain method. Results are presented considering two relevant source configurations.
{"title":"Shielding performance of ferromagnetic cylindrical cans","authors":"S. Celozzi, M. D'amore","doi":"10.1109/ISEMC.1996.561209","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561209","url":null,"abstract":"The analysis of shielding performance of ferromagnetic cylindrical cans is presented. The near field loop source is described introducing wave impedances which depend upon the orientation of the source. Hysteresis is taken into account accurately by means of a nonlinear implicit differential equation. The time domain solution procedure is based on the finite element time domain method. Results are presented considering two relevant source configurations.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116882788","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561425
H. Benitez
The European Union EMC compliance process is more complex than it may first appear. This paper helps the manufacturer understand product standards and the available routes to compliance that support the EMC Directive. In addition, a cradle-to-grave process is reviewed that has proven to be effective in assuring manufacturer's product compliance goals are achieved.
{"title":"Routes to EMC compliance: a manufacturer has choices","authors":"H. Benitez","doi":"10.1109/ISEMC.1996.561425","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561425","url":null,"abstract":"The European Union EMC compliance process is more complex than it may first appear. This paper helps the manufacturer understand product standards and the available routes to compliance that support the EMC Directive. In addition, a cradle-to-grave process is reviewed that has proven to be effective in assuring manufacturer's product compliance goals are achieved.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122922950","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 : 1996-08-19DOI: 10.1109/ISEMC.1996.561260
J. Quine, C. Brown, K. Fisher, J.P. Streeter, A. Pesta
This paper discusses the experimental characterization at microwave frequencies of leakage sources such as gasketed seams and attenuating cover panels by methods that employ a reverberation chamber (REVCH) to measure the total power radiated into the REVCH by the leakage source. The preferred characterization of a leakage source is in terms of the effective transmission area (ETA) defined as the total radiated leakage power (watts) divided by the microwave flux (watts per square meter) incident on the leakage source from outside the REVCH. Several sources of error that can occur in measuring ETA are identified, non-uniformities in material and cross-sectional dimensions of the test panel or gasket being a significant source of error. The non-uniformities can result in "hot spots" which have unknown size and position along the length of a gasket or over the area of a panel, and therefore, can have uncertain power coupling into the REVCH. The results presented in this paper indicate clearly the need to further modify MIL-STD-285 to include a requirement for some form of mode stirring. Furthermore, "ETA" should be adopted as a preferred characterization for the microwave shielding performance of gaskets and cover panels.
{"title":"Testing of microwave shielding gaskets and cover panels-recent work at Rome Laboratories","authors":"J. Quine, C. Brown, K. Fisher, J.P. Streeter, A. Pesta","doi":"10.1109/ISEMC.1996.561260","DOIUrl":"https://doi.org/10.1109/ISEMC.1996.561260","url":null,"abstract":"This paper discusses the experimental characterization at microwave frequencies of leakage sources such as gasketed seams and attenuating cover panels by methods that employ a reverberation chamber (REVCH) to measure the total power radiated into the REVCH by the leakage source. The preferred characterization of a leakage source is in terms of the effective transmission area (ETA) defined as the total radiated leakage power (watts) divided by the microwave flux (watts per square meter) incident on the leakage source from outside the REVCH. Several sources of error that can occur in measuring ETA are identified, non-uniformities in material and cross-sectional dimensions of the test panel or gasket being a significant source of error. The non-uniformities can result in \"hot spots\" which have unknown size and position along the length of a gasket or over the area of a panel, and therefore, can have uncertain power coupling into the REVCH. The results presented in this paper indicate clearly the need to further modify MIL-STD-285 to include a requirement for some form of mode stirring. Furthermore, \"ETA\" should be adopted as a preferred characterization for the microwave shielding performance of gaskets and cover panels.","PeriodicalId":296175,"journal":{"name":"Proceedings of Symposium on Electromagnetic Compatibility","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127897891","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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