Pub Date : 1997-12-31DOI: 10.1109/PVSC.1997.654330
M. Yang, H. Izumi, M. Sato, S. Matsunaga, T. Takamoto, K. Tsuzuki, T. Amono, M. Yamaguchi
A combined 3 kW PV-thermal system has been proposed for home use. Combining PV and thermal conversion makes this system economically efficient and competitive with traditional power supplies. GaAs and Si concentrator solar cells have been measured under concentration as a candidate for use in this system. InGaP/GaAs tandem solar cells designed for 1-sun operation have been examined under concentration. The potential use of GaInP/GaAs tandem solar cells has been analyzed for this application. The properties of the thermal transfer unit of this system has been evaluated including the cooling of the solar cell holder.
{"title":"A 3 kW PV-thermal system for home use","authors":"M. Yang, H. Izumi, M. Sato, S. Matsunaga, T. Takamoto, K. Tsuzuki, T. Amono, M. Yamaguchi","doi":"10.1109/PVSC.1997.654330","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654330","url":null,"abstract":"A combined 3 kW PV-thermal system has been proposed for home use. Combining PV and thermal conversion makes this system economically efficient and competitive with traditional power supplies. GaAs and Si concentrator solar cells have been measured under concentration as a candidate for use in this system. InGaP/GaAs tandem solar cells designed for 1-sun operation have been examined under concentration. The potential use of GaInP/GaAs tandem solar cells has been analyzed for this application. The properties of the thermal transfer unit of this system has been evaluated including the cooling of the solar cell holder.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122880017","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654152
R. Raffaelle, J. Mantovani, R.B. Friedfeld, S. Bailey, S. Hubbard
The authors have been investigating the electrochemical deposition of thin films and junctions based on copper indium diselenide (CIS). CIS is considered to be one of the best absorber materials for use in polycrystalline thin film photovoltaic solar cells. Electrodeposition is a simple and inexpensive method for producing thin-film CIS. They have produced both p and n type CIS thin films, as well as a CIS p-n junction electrodeposited from a single aqueous solution. Optical bandgaps were determined for these thin films using transmission spectroscopy. Current versus voltage characteristics were measured for Schottky barriers on the individual films and for the p-n junction.
{"title":"Electrodeposited CuInSe/sub 2/ thin film devices","authors":"R. Raffaelle, J. Mantovani, R.B. Friedfeld, S. Bailey, S. Hubbard","doi":"10.1109/PVSC.1997.654152","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654152","url":null,"abstract":"The authors have been investigating the electrochemical deposition of thin films and junctions based on copper indium diselenide (CIS). CIS is considered to be one of the best absorber materials for use in polycrystalline thin film photovoltaic solar cells. Electrodeposition is a simple and inexpensive method for producing thin-film CIS. They have produced both p and n type CIS thin films, as well as a CIS p-n junction electrodeposited from a single aqueous solution. Optical bandgaps were determined for these thin films using transmission spectroscopy. Current versus voltage characteristics were measured for Schottky barriers on the individual films and for the p-n junction.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114380398","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 : 1997-12-31DOI: 10.1109/PVSC.1997.653942
W. Kusian, Hans-Christoph Ostendorf, J. Palm, A.L. Endros
Low costs and high efficiency are driving the development of crystalline silicon solar cells towards thinner wafers. The optimum wafer thickness with respect to high efficiencies is around 60-100 /spl mu/m. Tri-crystalline silicon is a promising material to enter this region on production scale. It shows an improved mechanical stability and can be sawn into thinner wafers. The electric properties are investigated by diffusion length measurements performed after each solar cell process step with the laterally resolved ELYMAT technique. Depending on the damage etching process the diffusion length L is between 100 and 300 /spl mu/m. For alkaline etched wafers a correlation between L and the etch pit density is found. After emitter diffusion the diffusion length increases to values between 400 /spl mu/m and 500 /spl mu/m and stays at that level even for subsequent processing steps.
{"title":"Diffusion length of tri-crystalline silicon during solar cell processing","authors":"W. Kusian, Hans-Christoph Ostendorf, J. Palm, A.L. Endros","doi":"10.1109/PVSC.1997.653942","DOIUrl":"https://doi.org/10.1109/PVSC.1997.653942","url":null,"abstract":"Low costs and high efficiency are driving the development of crystalline silicon solar cells towards thinner wafers. The optimum wafer thickness with respect to high efficiencies is around 60-100 /spl mu/m. Tri-crystalline silicon is a promising material to enter this region on production scale. It shows an improved mechanical stability and can be sawn into thinner wafers. The electric properties are investigated by diffusion length measurements performed after each solar cell process step with the laterally resolved ELYMAT technique. Depending on the damage etching process the diffusion length L is between 100 and 300 /spl mu/m. For alkaline etched wafers a correlation between L and the etch pit density is found. After emitter diffusion the diffusion length increases to values between 400 /spl mu/m and 500 /spl mu/m and stays at that level even for subsequent processing steps.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"138 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125820075","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654109
J. Granata, J. Sites, S. Asher, R. Matson
Sodium was deliberately introduced into CuInSe/sub 2/ and Cu(In,Ga)Se/sub 2/ photovoltaic solar cells in a controlled manner. The amount of sodium added was varied in order to pinpoint the range of sodium concentrations in the CuIn(Ga)Se/sub 2/ film for optimal performance. Films were analyzed using secondary ion mass spectroscopy and induced-coupling plasma spectroscopy to quantify the sodium concentration. The results are compared with the calculation. Finished devices show improvements in open-circuit voltage, fill factor and hole density for sodium concentrations in the range of approximately 0.05 to 0.5 atomic percent.
{"title":"Quantitative incorporation of sodium in CuInSe/sub 2/ and Cu(In,Ga)Se/sub 2/ photovoltaic devices","authors":"J. Granata, J. Sites, S. Asher, R. Matson","doi":"10.1109/PVSC.1997.654109","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654109","url":null,"abstract":"Sodium was deliberately introduced into CuInSe/sub 2/ and Cu(In,Ga)Se/sub 2/ photovoltaic solar cells in a controlled manner. The amount of sodium added was varied in order to pinpoint the range of sodium concentrations in the CuIn(Ga)Se/sub 2/ film for optimal performance. Films were analyzed using secondary ion mass spectroscopy and induced-coupling plasma spectroscopy to quantify the sodium concentration. The results are compared with the calculation. Finished devices show improvements in open-circuit voltage, fill factor and hole density for sodium concentrations in the range of approximately 0.05 to 0.5 atomic percent.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"305 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132934666","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654310
M. Fitzgerald, M. Mrohs
As the markets for photovoltaics grow and become more main stream, customers and financing institutions will increasingly require assurances of design, installation, and maintenance competency and professionalism. This can either evolve as a large number of uncoordinated and dissimilar local and regional regulations, or may be developed within a common framework that ensures quality, continuity, and transportability reducing the ultimate burden of compliance on designers and installers. This paper is a summary of the issues confronting efforts to develop industry standards, current efforts to develop global standards for systems hardware and training, and projections for the phased development of these quality programs for the photovoltaics industry. The paper also discusses the impact of such a standardization program on access to financing and the impact on the creation of local, sustainable jobs.
{"title":"The infrastructure path to a sustainable world market for photovoltaics","authors":"M. Fitzgerald, M. Mrohs","doi":"10.1109/PVSC.1997.654310","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654310","url":null,"abstract":"As the markets for photovoltaics grow and become more main stream, customers and financing institutions will increasingly require assurances of design, installation, and maintenance competency and professionalism. This can either evolve as a large number of uncoordinated and dissimilar local and regional regulations, or may be developed within a common framework that ensures quality, continuity, and transportability reducing the ultimate burden of compliance on designers and installers. This paper is a summary of the issues confronting efforts to develop industry standards, current efforts to develop global standards for systems hardware and training, and projections for the phased development of these quality programs for the photovoltaics industry. The paper also discusses the impact of such a standardization program on access to financing and the impact on the creation of local, sustainable jobs.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133141076","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654104
D. Albin, D. Rose, R. Dhere, D. Levi, L. Woods, A. Swartzlander, P. Sheldon
Close-spaced-sublimated (CSS) CdS films exhibit strong fundamental edge luminescence, high optical absorption and a bandgap of /spl sim/2.41 eV. Structurally, these films show good crystallinity with thickness-dependent grain sizes that vary between 100-400 nm. In contrast, chemical-bath-deposited (CBD) CdS exhibits subband luminescence, lower absorption and a thickness-dependent bandgap. These films have CdS grains typically less than 50 nm in size and poorer crystallinity. However, CdTe devices fabricated with these lower "quality" CBD CdS films yield higher V/sub oc/s and fill factors. Carrier lifetimes in finished CSS CdS devices measured between 100 and 200 ps while lifetimes in CBD CdS devices were much higher (>500 ps). Compositional differences in the Cd/(S+Te) ratio at the interface suggest the possibility of lower CdS doping and higher CdTe compensation as one reason for lower V/sub oc/s in CSS CdS devices.
{"title":"Comparison study of close-spaced sublimated and chemical bath deposited CdS films: effects on CdTe solar cells","authors":"D. Albin, D. Rose, R. Dhere, D. Levi, L. Woods, A. Swartzlander, P. Sheldon","doi":"10.1109/PVSC.1997.654104","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654104","url":null,"abstract":"Close-spaced-sublimated (CSS) CdS films exhibit strong fundamental edge luminescence, high optical absorption and a bandgap of /spl sim/2.41 eV. Structurally, these films show good crystallinity with thickness-dependent grain sizes that vary between 100-400 nm. In contrast, chemical-bath-deposited (CBD) CdS exhibits subband luminescence, lower absorption and a thickness-dependent bandgap. These films have CdS grains typically less than 50 nm in size and poorer crystallinity. However, CdTe devices fabricated with these lower \"quality\" CBD CdS films yield higher V/sub oc/s and fill factors. Carrier lifetimes in finished CSS CdS devices measured between 100 and 200 ps while lifetimes in CBD CdS devices were much higher (>500 ps). Compositional differences in the Cd/(S+Te) ratio at the interface suggest the possibility of lower CdS doping and higher CdTe compensation as one reason for lower V/sub oc/s in CSS CdS devices.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128684718","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654320
J. Stone, H. Ullal, E. Sastry
A cooperative program was established in 1993 by the governments of India and the United States. The 50-50 cost share project funded $500,000 of PV power systems for home lighting, water pumping, battery charging and vaccine refrigeration systems in the Sundarbans region of West Bengal, India. The project was designed as a sustainable rural economic development initiative with the Ramakrishna Mission, a well-respected humanitarian nongovernment organization (NGO) in this remote area of India. Special attention was paid to building an infrastructure for financing, installing and maintaining the PV power systems. A before-and-after impact study on the beneficiaries is being done. Lessons learned to date are presented along with details of the installed systems.
{"title":"The Indo-US cooperative photovoltaic project","authors":"J. Stone, H. Ullal, E. Sastry","doi":"10.1109/PVSC.1997.654320","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654320","url":null,"abstract":"A cooperative program was established in 1993 by the governments of India and the United States. The 50-50 cost share project funded $500,000 of PV power systems for home lighting, water pumping, battery charging and vaccine refrigeration systems in the Sundarbans region of West Bengal, India. The project was designed as a sustainable rural economic development initiative with the Ramakrishna Mission, a well-respected humanitarian nongovernment organization (NGO) in this remote area of India. Special attention was paid to building an infrastructure for financing, installing and maintaining the PV power systems. A before-and-after impact study on the beneficiaries is being done. Lessons learned to date are presented along with details of the installed systems.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121756963","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654292
M. Nowlan, J.C. Maglitta, G. Darkazalli, T. Lamp
New lightweight photovoltaic modules are being developed for powering high altitude unmanned aerial vehicles (UAVs). Modified low-cost terrestrial solar cell and module technologies are being applied to minimize vehicle cost. New processes were developed for assembling thin solar cells, encapsulant films, and cover films. An innovative by-pass diode mounting approach that uses a solar cell as a heat spreader was devised and tested. Materials and processes are evaluated through accelerated environmental testing.
{"title":"Ultralight photovoltaic modules for unmanned aerial vehicles","authors":"M. Nowlan, J.C. Maglitta, G. Darkazalli, T. Lamp","doi":"10.1109/PVSC.1997.654292","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654292","url":null,"abstract":"New lightweight photovoltaic modules are being developed for powering high altitude unmanned aerial vehicles (UAVs). Modified low-cost terrestrial solar cell and module technologies are being applied to minimize vehicle cost. New processes were developed for assembling thin solar cells, encapsulant films, and cover films. An innovative by-pass diode mounting approach that uses a solar cell as a heat spreader was devised and tested. Materials and processes are evaluated through accelerated environmental testing.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124897544","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654287
W. Herrmann, W. Wiesner, W. Vaassen
Solar cell manufacturers should provide information to module manufacturers about the operation of their cells under reverse biased conditions. The inhomogeneous behaviour of cells under reverse biased conditions needs further investigation. In particular, cell damage during manufacture should be evaluated. To guarantee resistance of the module design to thermal overload due to partial shading, the number of cells in a sub-string should be limited to 20. The hot-spot test procedure of IEC 1215 should be generalised for all types of cell interconnection circuits. The selection of the worst case cell should be improved by measurement of the module current at the characteristic break point of the I-V characteristic.
{"title":"Hot spot investigations on PV modules-new concepts for a test standard and consequences for module design with respect to bypass diodes","authors":"W. Herrmann, W. Wiesner, W. Vaassen","doi":"10.1109/PVSC.1997.654287","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654287","url":null,"abstract":"Solar cell manufacturers should provide information to module manufacturers about the operation of their cells under reverse biased conditions. The inhomogeneous behaviour of cells under reverse biased conditions needs further investigation. In particular, cell damage during manufacture should be evaluated. To guarantee resistance of the module design to thermal overload due to partial shading, the number of cells in a sub-string should be limited to 20. The hot-spot test procedure of IEC 1215 should be generalised for all types of cell interconnection circuits. The selection of the worst case cell should be improved by measurement of the module current at the characteristic break point of the I-V characteristic.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124062559","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 : 1997-12-31DOI: 10.1109/PVSC.1997.654103
L. Olsen, W. Lei, F. Addis, W. Shafarman, M. Contreras, K. Ramanathan
This paper describes investigations of CIS and CIGS solar cells with ZnO buffer layers. These studies are a result of a team effort between investigators at Washington State University (WSU), the Institute Of Energy Conversion (IEC) and the National Renewable Energy Laboratory (NREL). Cells with ZnO buffer layers were fabricated with both Siemens CIS and NREL CIGS substrates. An active area efficiency of 13.95% was achieved for a ZnO/CIGS cell. ZnO buffer layers are grown by reacting a zinc adduct with tetrahydrofuran using a two-step approach: growth of approximately 100 /spl Aring/ of ZnO at 250/spl deg/C; and then growth of 500 to 700 /spl Aring/ of ZnO at 100/spl deg/C. The high temperature step is necessary to achieve good cell performance. It appears that exposure of CIGS to hydrogen at 250/spl deg/C may remove contaminants and/or passivate recombination centers on the surface and subsurface regions.
{"title":"High efficiency CIGS and CIS cells with CVD ZnO buffer layers","authors":"L. Olsen, W. Lei, F. Addis, W. Shafarman, M. Contreras, K. Ramanathan","doi":"10.1109/PVSC.1997.654103","DOIUrl":"https://doi.org/10.1109/PVSC.1997.654103","url":null,"abstract":"This paper describes investigations of CIS and CIGS solar cells with ZnO buffer layers. These studies are a result of a team effort between investigators at Washington State University (WSU), the Institute Of Energy Conversion (IEC) and the National Renewable Energy Laboratory (NREL). Cells with ZnO buffer layers were fabricated with both Siemens CIS and NREL CIGS substrates. An active area efficiency of 13.95% was achieved for a ZnO/CIGS cell. ZnO buffer layers are grown by reacting a zinc adduct with tetrahydrofuran using a two-step approach: growth of approximately 100 /spl Aring/ of ZnO at 250/spl deg/C; and then growth of 500 to 700 /spl Aring/ of ZnO at 100/spl deg/C. The high temperature step is necessary to achieve good cell performance. It appears that exposure of CIGS to hydrogen at 250/spl deg/C may remove contaminants and/or passivate recombination centers on the surface and subsurface regions.","PeriodicalId":251166,"journal":{"name":"Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114719579","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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