Pub Date : 2014-05-07DOI: 10.1109/ISSE.2014.6887556
D. Seehase, H. Huth, Arne Neiser, M. Nowottnick
For the energetic support of reflow soldering an exothermic reacting paste has been developed. This paste is applied on electronic assemblies adjacent to solder paste deposits before reflow soldering. During the reflow process a chemical reaction inside the paste is releasing energy in the form of heat. This heat is assisting in melting up the solder paste depots, hence allowing the processing of large components at lower peak temperatures. Such created solder joints are analyzed here towards their reliability. Also two examples of employing the reacting paste to aid in the soldering process of large components are given.
{"title":"Reactive paste for reflow soldering of large components","authors":"D. Seehase, H. Huth, Arne Neiser, M. Nowottnick","doi":"10.1109/ISSE.2014.6887556","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887556","url":null,"abstract":"For the energetic support of reflow soldering an exothermic reacting paste has been developed. This paste is applied on electronic assemblies adjacent to solder paste deposits before reflow soldering. During the reflow process a chemical reaction inside the paste is releasing energy in the form of heat. This heat is assisting in melting up the solder paste depots, hence allowing the processing of large components at lower peak temperatures. Such created solder joints are analyzed here towards their reliability. Also two examples of employing the reacting paste to aid in the soldering process of large components are given.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123275940","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887633
T. Garami, Norbert Reti, O. Krammer
This paper focuses on the cooling rate of soldering process. Our target was to create a well-controlled equipment that is used to set the adjustable slope of the cooling curve with three special sections. The three sections are: near the melting point, above and below the melting point. The unit uses cooling fans to create a forced convection air flow. K-type thermocouple is used for the temperature measurement in the temperature feedback loop. The cooling rate is adjustable in a wide range, between 0.25 K/s and 10 K/s. To understand the effect of different cooling rates, the undercooling mechanism near the solidus point of the solder has to be investigated. Experiments showed that there is a flat section in the temperature profile when the solder reaches the solidus point during cooling. With the control unit this phenomenon and the effect of various cooling rates can also be investigated.
{"title":"Controlling the cooling rate of soldering processes with PIC microcontroller","authors":"T. Garami, Norbert Reti, O. Krammer","doi":"10.1109/ISSE.2014.6887633","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887633","url":null,"abstract":"This paper focuses on the cooling rate of soldering process. Our target was to create a well-controlled equipment that is used to set the adjustable slope of the cooling curve with three special sections. The three sections are: near the melting point, above and below the melting point. The unit uses cooling fans to create a forced convection air flow. K-type thermocouple is used for the temperature measurement in the temperature feedback loop. The cooling rate is adjustable in a wide range, between 0.25 K/s and 10 K/s. To understand the effect of different cooling rates, the undercooling mechanism near the solidus point of the solder has to be investigated. Experiments showed that there is a flat section in the temperature profile when the solder reaches the solidus point during cooling. With the control unit this phenomenon and the effect of various cooling rates can also be investigated.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127790704","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887614
S. Pleshkova, K. Peeva, Al. Bekyarski
Thermo visual images are produced from thermo vision or infrared cameras and are the source of visual information in the night or darkness for observation of objects and people in widespread security systems. There is usually the need of transmission of thermal images in these surveillance thermo vision security systems. The communication systems used for this purpose introduce the noises and distortions. This leads to quality decreasing of the received thermal images. Therefore, the algorithms necessary to detect and tracking objects and people work poorly and the precision is not satisfactory. The goal of this article is to propose and testing with simulation an appropriate method and algorithm for thermal images quality estimation received from a surveillance thermo vision communication system. The base of this proposition are the methods and algorithms developed for the visible images, but here they are modified according to the specific nature and characteristics of the thermal images and also taking in the account the requirements of the surveillance security systems - to detect and tracking with an appropriate precision the objects and people of interest in area of observation.
{"title":"Received thermal images quality estimation in thermo vision communication systems","authors":"S. Pleshkova, K. Peeva, Al. Bekyarski","doi":"10.1109/ISSE.2014.6887614","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887614","url":null,"abstract":"Thermo visual images are produced from thermo vision or infrared cameras and are the source of visual information in the night or darkness for observation of objects and people in widespread security systems. There is usually the need of transmission of thermal images in these surveillance thermo vision security systems. The communication systems used for this purpose introduce the noises and distortions. This leads to quality decreasing of the received thermal images. Therefore, the algorithms necessary to detect and tracking objects and people work poorly and the precision is not satisfactory. The goal of this article is to propose and testing with simulation an appropriate method and algorithm for thermal images quality estimation received from a surveillance thermo vision communication system. The base of this proposition are the methods and algorithms developed for the visible images, but here they are modified according to the specific nature and characteristics of the thermal images and also taking in the account the requirements of the surveillance security systems - to detect and tracking with an appropriate precision the objects and people of interest in area of observation.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115495485","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887630
C. Tămaş, N. Codreanu, C. Grecu, I. Marghescu
The paper investigates and compares two different solutions to improve a printed circuit board designed for a portable computer main board. The issue represents the analog circuits and switching power supplies. The main example is a simple analog circuit, low dropout regulator (LDO), integrated into a complex analog circuit. The LDO stability versus the printed circuit board (PCB) design rules represents today a real challenge for electrical engineers and PCB designers.
{"title":"Investigations on silicon and PCB ground system design for new 1.2V DDR4 power sources","authors":"C. Tămaş, N. Codreanu, C. Grecu, I. Marghescu","doi":"10.1109/ISSE.2014.6887630","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887630","url":null,"abstract":"The paper investigates and compares two different solutions to improve a printed circuit board designed for a portable computer main board. The issue represents the analog circuits and switching power supplies. The main example is a simple analog circuit, low dropout regulator (LDO), integrated into a complex analog circuit. The LDO stability versus the printed circuit board (PCB) design rules represents today a real challenge for electrical engineers and PCB designers.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131529191","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887613
Snezhana Pleshkova-Bekyarska, Al. Bekyarski
Motion detection of objects or people is an important operation in visual and also in thermo visual surveillance systems. From speed of execution and accuracy of motion detection operation strongly are depended the main characteristics of a real working surveillance system. Therefore, the goal of this article is to develop of a multicore DSP thermal image sequence processing module suitable for real time objects or people motion detection and tracking and also to present here the experimental results from this development. The development of multicore DSP module is based on Xilinx module Zynq-7000 All Programmable SoC. The proposed algorithm of motion detection in thermal images is first modeled using OpenCV library functions for image processing, and then the algorithm is accelerating using Xilinx Vivado HLS Video Libraries to implement the algorithm of motion detection in thermal images in Xilinx module Zynq-7000. The presented in this article experimental results show the ability to detect in real time motions of objects or people in thermal images and to use the results for next steps of a whole algorithm for thermo visual surveillance - objects and people tracking in thermal images.
{"title":"Multicore DSPs thermal image sequence processing for real time motion detection in thermal surveillance system","authors":"Snezhana Pleshkova-Bekyarska, Al. Bekyarski","doi":"10.1109/ISSE.2014.6887613","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887613","url":null,"abstract":"Motion detection of objects or people is an important operation in visual and also in thermo visual surveillance systems. From speed of execution and accuracy of motion detection operation strongly are depended the main characteristics of a real working surveillance system. Therefore, the goal of this article is to develop of a multicore DSP thermal image sequence processing module suitable for real time objects or people motion detection and tracking and also to present here the experimental results from this development. The development of multicore DSP module is based on Xilinx module Zynq-7000 All Programmable SoC. The proposed algorithm of motion detection in thermal images is first modeled using OpenCV library functions for image processing, and then the algorithm is accelerating using Xilinx Vivado HLS Video Libraries to implement the algorithm of motion detection in thermal images in Xilinx module Zynq-7000. The presented in this article experimental results show the ability to detect in real time motions of objects or people in thermal images and to use the results for next steps of a whole algorithm for thermo visual surveillance - objects and people tracking in thermal images.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133326707","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887590
K. Dušek, I. Beshajová Pelikánová, D. Bušek, Marek Zeidler
Solder paste printing is one of the most important steps in the surface mount technology, which has high influence on the resulting quality of solder joints. To achieve a good joint quality, the solder paste should have specific properties like adhesion, viscosity, size of the solder alloy particles, amount of flux etc. This paper is focused on the measurement of the solder paste viscosity during its tempering and aging with possibility of regeneration of solder paste properties by jelly flux. Three types of solder pastes were used in the experiment: Sn95.5Ag4Cu0.5, Sn96.5Ag3Cu0.5 and Sn62Pb36Ag2. Viscosity of solder paste is measured from storing temperature to the ambient temperature. Aging of solder pastes is made in ambient atmosphere. Regeneration of solder paste properties after aging was done by adding of jelly flux Amtech 4300/LF-4300-TF. The viscosity of pure solder paste before aging, pure solder paste after aging and solder paste after aging regenerated by jelly flux was measured by rotation viscometer Brookfield Synchroelectric Viscometer, model HBT. The article describes if the addition of jelly flux to the aged solder pastes regenerates their properties.
{"title":"Measurements of solder paste viscosity during its tempering and aging","authors":"K. Dušek, I. Beshajová Pelikánová, D. Bušek, Marek Zeidler","doi":"10.1109/ISSE.2014.6887590","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887590","url":null,"abstract":"Solder paste printing is one of the most important steps in the surface mount technology, which has high influence on the resulting quality of solder joints. To achieve a good joint quality, the solder paste should have specific properties like adhesion, viscosity, size of the solder alloy particles, amount of flux etc. This paper is focused on the measurement of the solder paste viscosity during its tempering and aging with possibility of regeneration of solder paste properties by jelly flux. Three types of solder pastes were used in the experiment: Sn95.5Ag4Cu0.5, Sn96.5Ag3Cu0.5 and Sn62Pb36Ag2. Viscosity of solder paste is measured from storing temperature to the ambient temperature. Aging of solder pastes is made in ambient atmosphere. Regeneration of solder paste properties after aging was done by adding of jelly flux Amtech 4300/LF-4300-TF. The viscosity of pure solder paste before aging, pure solder paste after aging and solder paste after aging regenerated by jelly flux was measured by rotation viscometer Brookfield Synchroelectric Viscometer, model HBT. The article describes if the addition of jelly flux to the aged solder pastes regenerates their properties.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133304367","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887565
B. Platek, T. Falat, J. Felba
This paper is aimed to the evaluation of interfacial thermal resistance between carbon nanotube and crystal of silicon by using molecular dynamics simulation. The calculations were executed by implemented algorithm for enforcing the heat flow in the model (PERL script language) in Forcite module of Materials Studio software (Accelrys, Software Inc.). Two models of the interface between carbon nanotube and silicon rod were proposed. The first one was with closed ends of CNT and the second one with opened ends CNT bonded to the silicon.
{"title":"Evaluation of the interfacial resistance between carbon nanotube and silicon by using molecular dynamics simulations","authors":"B. Platek, T. Falat, J. Felba","doi":"10.1109/ISSE.2014.6887565","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887565","url":null,"abstract":"This paper is aimed to the evaluation of interfacial thermal resistance between carbon nanotube and crystal of silicon by using molecular dynamics simulation. The calculations were executed by implemented algorithm for enforcing the heat flow in the model (PERL script language) in Forcite module of Materials Studio software (Accelrys, Software Inc.). Two models of the interface between carbon nanotube and silicon rod were proposed. The first one was with closed ends of CNT and the second one with opened ends CNT bonded to the silicon.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129939093","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887607
K. Jankowski, A. Wymyslowski
Occurring from many years a impetuous growth of electronic devices manufacturing, induced by introducing a new functionalities for customers and moving towards replacing hazardous substances such as lead in electrical and electronic equipment caused that a reliability of solder joints is more important issue in electronic assembly. Reliability of solder joints plays a major role in the electronic packaging. Indeed, the solder joints serve not only for the transmitting of electrical signals, but also for the heat transportation and as a structural support which is one of the most important aspects. Therefore very important is to estimate behavior of solder joints in various work conditions. The best way to solve that problem is to take a focus on creep and fatigue phenomena which initiate degradation process. Currently creep and fatigue phenomena are considered only in self-dependent way. Consequently reliability prototyping is long lasting and expensive. The usual tests take advantage of only one dominating failure mode which can last even for a number of months. In addition all failure analysis are done under the simplified conditions what means that obtained results are not properly reliable. To accelerate that kind of tests creep and fatigue phenomena should be taken into account at the same time [1]. That combination can help to develop analytical, experimental and numerical approach for understanding the combined multi-loading and multi-failure problem. Therefore an appropriate understanding and development of analytical methods and experimental tools for multi-failure criteria analysis could be very helpful. The study will present new method, which allow introduce multi-failure conditions to tested joints.
{"title":"Acceleration of life prediction of solder joints using multi-failure criteria","authors":"K. Jankowski, A. Wymyslowski","doi":"10.1109/ISSE.2014.6887607","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887607","url":null,"abstract":"Occurring from many years a impetuous growth of electronic devices manufacturing, induced by introducing a new functionalities for customers and moving towards replacing hazardous substances such as lead in electrical and electronic equipment caused that a reliability of solder joints is more important issue in electronic assembly. Reliability of solder joints plays a major role in the electronic packaging. Indeed, the solder joints serve not only for the transmitting of electrical signals, but also for the heat transportation and as a structural support which is one of the most important aspects. Therefore very important is to estimate behavior of solder joints in various work conditions. The best way to solve that problem is to take a focus on creep and fatigue phenomena which initiate degradation process. Currently creep and fatigue phenomena are considered only in self-dependent way. Consequently reliability prototyping is long lasting and expensive. The usual tests take advantage of only one dominating failure mode which can last even for a number of months. In addition all failure analysis are done under the simplified conditions what means that obtained results are not properly reliable. To accelerate that kind of tests creep and fatigue phenomena should be taken into account at the same time [1]. That combination can help to develop analytical, experimental and numerical approach for understanding the combined multi-loading and multi-failure problem. Therefore an appropriate understanding and development of analytical methods and experimental tools for multi-failure criteria analysis could be very helpful. The study will present new method, which allow introduce multi-failure conditions to tested joints.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130240931","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887609
R. Bozomitu, V. Cehan, R. Lupu
This paper presents a new CMOS differential input FM quadrature demodulator for integrated circuits. The proposed circuit is based on Bilotti's quadrature demodulator that uses an external differential phase shift network and a differential phase detector with a single ended output. The phase detector is represented by an analog multiplier implemented with a Gilbert cell and the phase shift network is an external RLC resonator circuit. The current consumption of the FM detection stage is about 258μA from a 3.3V supply voltage. The simulations performed in 0.13μm CMOS technology confirm the theoretical result.
{"title":"A new CMOS differential input FM quadrature demodulator","authors":"R. Bozomitu, V. Cehan, R. Lupu","doi":"10.1109/ISSE.2014.6887609","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887609","url":null,"abstract":"This paper presents a new CMOS differential input FM quadrature demodulator for integrated circuits. The proposed circuit is based on Bilotti's quadrature demodulator that uses an external differential phase shift network and a differential phase detector with a single ended output. The phase detector is represented by an analog multiplier implemented with a Gilbert cell and the phase shift network is an external RLC resonator circuit. The current consumption of the FM detection stage is about 258μA from a 3.3V supply voltage. The simulations performed in 0.13μm CMOS technology confirm the theoretical result.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133425913","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 : 2014-05-07DOI: 10.1109/ISSE.2014.6887570
K. Hromadka, J. Štulík, J. Řeboun
This paper deals with a method for design and manufacturing of power electronic substrates. Thick conductive patterns are made by the additive deposition technique using thick copper conductor paste. Substrates with excellent thermal and electrical conductivity, high resistance to thermal cycling stress, high resolution of printed patterns and good mechanical properties are created by this manufacturing process. Gas-tight retort, we used for this specific substrate manufacturing process, is also described in this paper. Mechanical properties of substrates such as adhesion, as well as thermal and electrical properties, were tested in detail.
{"title":"Thick printed copper conductors on alumina substrates","authors":"K. Hromadka, J. Štulík, J. Řeboun","doi":"10.1109/ISSE.2014.6887570","DOIUrl":"https://doi.org/10.1109/ISSE.2014.6887570","url":null,"abstract":"This paper deals with a method for design and manufacturing of power electronic substrates. Thick conductive patterns are made by the additive deposition technique using thick copper conductor paste. Substrates with excellent thermal and electrical conductivity, high resistance to thermal cycling stress, high resolution of printed patterns and good mechanical properties are created by this manufacturing process. Gas-tight retort, we used for this specific substrate manufacturing process, is also described in this paper. Mechanical properties of substrates such as adhesion, as well as thermal and electrical properties, were tested in detail.","PeriodicalId":375711,"journal":{"name":"Proceedings of the 2014 37th International Spring Seminar on Electronics Technology","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129164967","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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