Pub Date : 2016-09-01DOI: 10.1109/THERMINIC.2016.7749037
D. Kendig, A. Tay, A. Shakouri
Shrinking features and growing device complexity with today's advanced devices has led to increased challenges of gaining a full understanding of device thermal behavior. At the same time, with higher power densities having a full understanding of the device static and dynamic thermal behavior is essential for ensuring optimal tradeoffs between performance and device reliability. Thermal imaging based on the Thermoreflectance Principle can meet the challenges imposed by these advanced devices by providing sub-micron spatial resolution and temporal resolution in the picosecond range. This thermal imaging concept will be described in this paper and compared to traditional imaging techniques. Several case studies will be presented to further illustrate the advantages of the thermoreflectance technique for thermal imaging.
{"title":"Thermal analysis of advanced microelectronic devices using thermoreflectance thermography","authors":"D. Kendig, A. Tay, A. Shakouri","doi":"10.1109/THERMINIC.2016.7749037","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7749037","url":null,"abstract":"Shrinking features and growing device complexity with today's advanced devices has led to increased challenges of gaining a full understanding of device thermal behavior. At the same time, with higher power densities having a full understanding of the device static and dynamic thermal behavior is essential for ensuring optimal tradeoffs between performance and device reliability. Thermal imaging based on the Thermoreflectance Principle can meet the challenges imposed by these advanced devices by providing sub-micron spatial resolution and temporal resolution in the picosecond range. This thermal imaging concept will be described in this paper and compared to traditional imaging techniques. Several case studies will be presented to further illustrate the advantages of the thermoreflectance technique for thermal imaging.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116268383","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7749077
S. Lefèvre, Aylin Yüksel Güngör, S. Gomés
The conductive adhesive material studied is composed with spheres of a polymer core covered with a nanometric thickness of silver and embedded in a polymer matrix. As the spheres are covered with metal of high thermal conductivity, an easy model has been developed based on the thermal resistance network method. Results have been compared with finite element method (FEM) simulations; only for cylinders - i.e. for a 2D problem - from now. The difference induced by the easy modelling compared to FEM simulation is less than 10%. Five different configurations of cylinder arrangement within the matrix were studied. Results have shown that the cylinder configuration is a key parameter to determine the thermal properties of the adhesive.
{"title":"Simulation of the thermal behavior of a conductive adhesive","authors":"S. Lefèvre, Aylin Yüksel Güngör, S. Gomés","doi":"10.1109/THERMINIC.2016.7749077","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7749077","url":null,"abstract":"The conductive adhesive material studied is composed with spheres of a polymer core covered with a nanometric thickness of silver and embedded in a polymer matrix. As the spheres are covered with metal of high thermal conductivity, an easy model has been developed based on the thermal resistance network method. Results have been compared with finite element method (FEM) simulations; only for cylinders - i.e. for a 2D problem - from now. The difference induced by the easy modelling compared to FEM simulation is less than 10%. Five different configurations of cylinder arrangement within the matrix were studied. Results have shown that the cylinder configuration is a key parameter to determine the thermal properties of the adhesive.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113983184","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7748646
C. Pleşa, M. Neag, C. Boianceanu, A. Negoita
This paper presents a design methodology based on electro-thermal simulations for the over-temperature protection (OTP) of low drop-out voltage regulators (LDO). The OTP monitors the die temperature developed within the LDO and shuts down the circuit when the temperature reaches a set maximum level (the OTP trigger point). The proposed methodology involves running iteratively electrical, thermal and electro-thermal simulations. It addresses two major issues: first, it allows the designer to identify the suitable location of the OTP sensor by considering the temperature distribution within the LDO's power-stage. Second, the OTP trigger point can be set accurately taking into account coupled electro-thermal phenomena, so that the circuit is shut down when any section of the die reaches the maximum allowable temperature. The proposed methodology is validated by measurements performed on an LDO designed using it.
{"title":"Design methodology for over-temperature protection of an LDO voltage regulator by using electro-thermal simulations","authors":"C. Pleşa, M. Neag, C. Boianceanu, A. Negoita","doi":"10.1109/THERMINIC.2016.7748646","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7748646","url":null,"abstract":"This paper presents a design methodology based on electro-thermal simulations for the over-temperature protection (OTP) of low drop-out voltage regulators (LDO). The OTP monitors the die temperature developed within the LDO and shuts down the circuit when the temperature reaches a set maximum level (the OTP trigger point). The proposed methodology involves running iteratively electrical, thermal and electro-thermal simulations. It addresses two major issues: first, it allows the designer to identify the suitable location of the OTP sensor by considering the temperature distribution within the LDO's power-stage. Second, the OTP trigger point can be set accurately taking into account coupled electro-thermal phenomena, so that the circuit is shut down when any section of the die reaches the maximum allowable temperature. The proposed methodology is validated by measurements performed on an LDO designed using it.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125766014","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7748640
Javier García, Nicolás Pérez, Melanie Mohn, T. Sieger, H. Schlorb, H. Reith, G. Schierning, K. Nielsch
Solid state refrigeration is of great interest due to its potential application in electronic and optoelectronic systems. Nowadays, macroscopic thermoelectric coolers are part of such systems and their cooling performance and reliability are well proven. However, the feasibility of microstructuring such kind of devices by means of photolithographic techniques, opens the possibility of integration on a chip for better local thermal management. Together with previous facts, electrodeposition processes are well known to be low cost, highly scalable and compatible with lithographic techniques. In this work we report on the fabrication of BiTe-based Micro-Thermoelectric Coolers by means of a mixed process flow involving photolithography and electrodeposition techniques. Materials and geometry of the device have been chosen to optimise the cooling performance on an integrated photonic system.
{"title":"Fabrication of a micro-thermoelectric cooler for room temperature applications by template assisted electrodeposition","authors":"Javier García, Nicolás Pérez, Melanie Mohn, T. Sieger, H. Schlorb, H. Reith, G. Schierning, K. Nielsch","doi":"10.1109/THERMINIC.2016.7748640","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7748640","url":null,"abstract":"Solid state refrigeration is of great interest due to its potential application in electronic and optoelectronic systems. Nowadays, macroscopic thermoelectric coolers are part of such systems and their cooling performance and reliability are well proven. However, the feasibility of microstructuring such kind of devices by means of photolithographic techniques, opens the possibility of integration on a chip for better local thermal management. Together with previous facts, electrodeposition processes are well known to be low cost, highly scalable and compatible with lithographic techniques. In this work we report on the fabrication of BiTe-based Micro-Thermoelectric Coolers by means of a mixed process flow involving photolithography and electrodeposition techniques. Materials and geometry of the device have been chosen to optimise the cooling performance on an integrated photonic system.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129959758","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7749057
B. Wunderle, D. May, M. A. Ras, S. Sheva, M. Schulz, M. Wohrmann, J. Bauer, J. Keller
We have developed a novel, rapid, robust and non-destructive experimental technique for in-situ monitoring of delamination of interfaces for electronic packages. The method is based on a simple thermal transducer matrix of so-called THIXELS (thermal pixels) which allows a spatially resolved real-time image of the current status of delamination. The transducers are small metal wire meanders which are driven and electrically read out using the well-known 3-omega method. This method has special advantages over other thermal contrast methods with respect to robustness, sensitivity and signal-to-noise ratio. Notable is the absence of cross-effects. The proof of concept has been furnished on an industry-grade flip-chip package with underfill on an organic substrate. The technique is especially powerful for buried interfaces, where time-honoured methods like scanning acoustic microscopy (SAM) cannot be applied. As the technique effectively performs a thermal diffusivity sensitive scan, it may not only be useful for stress testing during package qualification, but sensor applications on other fields of health monitoring seem also possible.
{"title":"In-situ monitoring of interface delamination by local thermal transducers exemplified for a flip-chip package","authors":"B. Wunderle, D. May, M. A. Ras, S. Sheva, M. Schulz, M. Wohrmann, J. Bauer, J. Keller","doi":"10.1109/THERMINIC.2016.7749057","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7749057","url":null,"abstract":"We have developed a novel, rapid, robust and non-destructive experimental technique for in-situ monitoring of delamination of interfaces for electronic packages. The method is based on a simple thermal transducer matrix of so-called THIXELS (thermal pixels) which allows a spatially resolved real-time image of the current status of delamination. The transducers are small metal wire meanders which are driven and electrically read out using the well-known 3-omega method. This method has special advantages over other thermal contrast methods with respect to robustness, sensitivity and signal-to-noise ratio. Notable is the absence of cross-effects. The proof of concept has been furnished on an industry-grade flip-chip package with underfill on an organic substrate. The technique is especially powerful for buried interfaces, where time-honoured methods like scanning acoustic microscopy (SAM) cannot be applied. As the technique effectively performs a thermal diffusivity sensitive scan, it may not only be useful for stress testing during package qualification, but sensor applications on other fields of health monitoring seem also possible.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133425648","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7749051
L. Mitterhuber, S. Defregger, R. Hammer, J. Magnien, F. Schrank, Stefan Horth, M. Hutter, E. Kraker
One key aspect in light emitting diode (LED) systems engineering lies in the understanding and management of the heat transfer during device operation. A deeper understanding of the thermal behavior of an LED module can be gained by an in-depth thermal path analysis. The three-dimensional heat path of the LED is influenced by its operating conditions (e.g. heat sink temperature, driving current, the properties of the thermal interface materials of the device attachment to the heatsink). In this paper, different operating conditions were systematically varied in a set of experiments and its corresponding numerical simulations making use of a statistical Design of Experiments (DOE) approach. The operating conditions were treated as experimental factors of the DOE and the responses were derived from analyzing the resulting structure functions. The results quantified not only the sensitivities of the responses (thermal transients) to the operating conditions but also showed the influence of temperature dependencies in the material properties on the thermal behavior of an LED module.
{"title":"Investigation of the temperature-dependent heat path of an LED module by thermal simulation and design of experiments","authors":"L. Mitterhuber, S. Defregger, R. Hammer, J. Magnien, F. Schrank, Stefan Horth, M. Hutter, E. Kraker","doi":"10.1109/THERMINIC.2016.7749051","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7749051","url":null,"abstract":"One key aspect in light emitting diode (LED) systems engineering lies in the understanding and management of the heat transfer during device operation. A deeper understanding of the thermal behavior of an LED module can be gained by an in-depth thermal path analysis. The three-dimensional heat path of the LED is influenced by its operating conditions (e.g. heat sink temperature, driving current, the properties of the thermal interface materials of the device attachment to the heatsink). In this paper, different operating conditions were systematically varied in a set of experiments and its corresponding numerical simulations making use of a statistical Design of Experiments (DOE) approach. The operating conditions were treated as experimental factors of the DOE and the responses were derived from analyzing the resulting structure functions. The results quantified not only the sensitivities of the responses (thermal transients) to the operating conditions but also showed the influence of temperature dependencies in the material properties on the thermal behavior of an LED module.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116862077","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7748645
T. Casper, U. Römer, S. Schöps
This work deals with the computation of industry-relevant bond wire failure probabilities in microelectronic packages. Under operating conditions, a package is subject to Joule heating that can lead to electrothermally induced failures. Manufacturing tolerances result, e.g., in uncertain bond wire geometries that often induce very small failure probabilities requiring a high number of Monte Carlo (MC) samples to be computed. Therefore, a hybrid MC sampling scheme that combines the use of an expensive computer model with a cheap surrogate is used. The fraction of surrogate evaluations is maximized using an iterative procedure, yielding accurate results at reduced cost. Moreover, the scheme is non-intrusive, i.e., existing code can be reused. The algorithm is used to compute the failure probability for an example package and the computational savings are assessed by performing a surrogate efficiency study.
{"title":"Determination of bond wire failure probabilities in microelectronic packages","authors":"T. Casper, U. Römer, S. Schöps","doi":"10.1109/THERMINIC.2016.7748645","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7748645","url":null,"abstract":"This work deals with the computation of industry-relevant bond wire failure probabilities in microelectronic packages. Under operating conditions, a package is subject to Joule heating that can lead to electrothermally induced failures. Manufacturing tolerances result, e.g., in uncertain bond wire geometries that often induce very small failure probabilities requiring a high number of Monte Carlo (MC) samples to be computed. Therefore, a hybrid MC sampling scheme that combines the use of an expensive computer model with a cheap surrogate is used. The fraction of surrogate evaluations is maximized using an iterative procedure, yielding accurate results at reduced cost. Moreover, the scheme is non-intrusive, i.e., existing code can be reused. The algorithm is used to compute the failure probability for an example package and the computational savings are assessed by performing a surrogate efficiency study.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123507375","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7748652
L. Codecasa, V. d’Alessandro, A. Magnani, N. Rinaldi
A novel partition-based approach for the extraction of Dynamic Compact Thermal Models is presented. With respect to previous approaches, this methodology allows reducing the complexity of the constructed models, from quadratically to linearly dependent on the number of independent heat sources. The proposed methodology is validated through the application to two state-of-the-art electronic systems.
{"title":"Novel partition-based approach to dynamic compact thermal modeling","authors":"L. Codecasa, V. d’Alessandro, A. Magnani, N. Rinaldi","doi":"10.1109/THERMINIC.2016.7748652","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7748652","url":null,"abstract":"A novel partition-based approach for the extraction of Dynamic Compact Thermal Models is presented. With respect to previous approaches, this methodology allows reducing the complexity of the constructed models, from quadratically to linearly dependent on the number of independent heat sources. The proposed methodology is validated through the application to two state-of-the-art electronic systems.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128897972","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7749058
S. Lei, R. Enright, A. Shen
To facilitate the design the heated-micro-resonator rings, we develop a numerical model. Particularly, an etching model based on a diffusion equation is implemented to distinguish the etched and non-etched regions. The simulations reveal that air trenches can significantly increase the thermal resistance and, as a result, reduce the power consumed in the heater to get the same tuning performance. It is found that the tunability of MRR is exponentially enhanced with the underetch level as RL > 0.825, whereas the tuning efficiency is almost the same, as RL <; 0.825. The tuning efficiency is ~0.1 nm/mW without air trenches, but it becomes 20× larger at the etched-through extreme.
{"title":"Design of heated-micro-resonator rings","authors":"S. Lei, R. Enright, A. Shen","doi":"10.1109/THERMINIC.2016.7749058","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7749058","url":null,"abstract":"To facilitate the design the heated-micro-resonator rings, we develop a numerical model. Particularly, an etching model based on a diffusion equation is implemented to distinguish the etched and non-etched regions. The simulations reveal that air trenches can significantly increase the thermal resistance and, as a result, reduce the power consumed in the heater to get the same tuning performance. It is found that the tunability of MRR is exponentially enhanced with the underetch level as RL > 0.825, whereas the tuning efficiency is almost the same, as RL <; 0.825. The tuning efficiency is ~0.1 nm/mW without air trenches, but it becomes 20× larger at the etched-through extreme.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132965152","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 : 2016-09-01DOI: 10.1109/THERMINIC.2016.7749066
G. Casano, S. Piva
The results are presented of an experimental investigation in a liquid cooled Switch-Mode Power Supply (SMPS). The target is a quantitative analysis of the performance of a cooling system designed to dissipate the heat generated by the active and passive electronic components of this SMPS, in order to limit its maximum operational temperature. The active components are cooled with a liquid cold-plate. The passive components are cooled with an air flow. The temperature of this airflow is controlled with Peltier cells coupled to the cold-late. Measurements are made of temperature and of electric efficiency of the SMPS. The cooling system is placed in an experimental tool where it is possible to measure and control the cooling liquid flow. A detailed analysis of the thermal behaviour of this cooling system is given. Finally, the practical significance of the problem is discussed.
{"title":"Peltier cells cooling system for switch mode power supply","authors":"G. Casano, S. Piva","doi":"10.1109/THERMINIC.2016.7749066","DOIUrl":"https://doi.org/10.1109/THERMINIC.2016.7749066","url":null,"abstract":"The results are presented of an experimental investigation in a liquid cooled Switch-Mode Power Supply (SMPS). The target is a quantitative analysis of the performance of a cooling system designed to dissipate the heat generated by the active and passive electronic components of this SMPS, in order to limit its maximum operational temperature. The active components are cooled with a liquid cold-plate. The passive components are cooled with an air flow. The temperature of this airflow is controlled with Peltier cells coupled to the cold-late. Measurements are made of temperature and of electric efficiency of the SMPS. The cooling system is placed in an experimental tool where it is possible to measure and control the cooling liquid flow. A detailed analysis of the thermal behaviour of this cooling system is given. Finally, the practical significance of the problem is discussed.","PeriodicalId":143150,"journal":{"name":"2016 22nd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128071119","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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