Pub Date : 2012-05-09DOI: 10.1109/ISSE.2012.6273141
M. Hrovat, D. Belavic, K. Makarovič, J. Holc
The ceramic micro electro-mechanical systems (C-MEMS) are fabricated in most cases by low-temperature co-fired ceramics (LTCC). The sensors of mechanical quantities are fundamental parts of MEMS, and thick-film resistor can sense mechanical deformations in the C-MEMS structures. Relatively low elastic moduli of LTCC ceramics as compared to alumina ceramics imply an increased sensitivity of sensing elements. Selected thick film resistors (Du Pont 2041 and ESL 3414) were evaluated as piezo-resistors for force sensors. The 2041 resistor was chosen because of its low noise, whereas the 3414-B was developed specially for use in strain gauges Resistors were screen printed and fired on various LTCC tapes as well as on alumina substrates. Electrical characteristics, i.e., sheet resistivities, noise indices and gauge factors were measured. LTCC tapes were analysed by scanning electron microscopy, energy dispersive X-ray analysis and X-ray powder analysis. Crystalline phases in LTCC materials were determined.
陶瓷微机电系统(C-MEMS)大多采用低温共烧陶瓷(LTCC)制备。机械量传感器是微机电系统的基本组成部分，厚膜电阻器可以检测C-MEMS结构中的机械变形。与氧化铝陶瓷相比，LTCC陶瓷相对较低的弹性模量意味着传感元件的灵敏度增加。选择厚膜电阻器(Du Pont 2041和ESL 3414)作为力传感器的压阻电阻器进行了评估。选择2041电阻器是因为它的低噪声，而3414-B是专门为应变片开发的，电阻器是丝网印刷的，并在各种LTCC磁带以及氧化铝基板上烧制。测量了电特性，即薄片电阻率、噪声指数和测量因子。采用扫描电子显微镜、能量色散x射线分析和x射线粉末分析对LTCC胶带进行了分析。测定了LTCC材料的晶相。
{"title":"Thick-film piezoresistors - benchmarking of LTCC substrates","authors":"M. Hrovat, D. Belavic, K. Makarovič, J. Holc","doi":"10.1109/ISSE.2012.6273141","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273141","url":null,"abstract":"The ceramic micro electro-mechanical systems (C-MEMS) are fabricated in most cases by low-temperature co-fired ceramics (LTCC). The sensors of mechanical quantities are fundamental parts of MEMS, and thick-film resistor can sense mechanical deformations in the C-MEMS structures. Relatively low elastic moduli of LTCC ceramics as compared to alumina ceramics imply an increased sensitivity of sensing elements. Selected thick film resistors (Du Pont 2041 and ESL 3414) were evaluated as piezo-resistors for force sensors. The 2041 resistor was chosen because of its low noise, whereas the 3414-B was developed specially for use in strain gauges Resistors were screen printed and fired on various LTCC tapes as well as on alumina substrates. Electrical characteristics, i.e., sheet resistivities, noise indices and gauge factors were measured. LTCC tapes were analysed by scanning electron microscopy, energy dispersive X-ray analysis and X-ray powder analysis. Crystalline phases in LTCC materials were determined.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124025628","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273074
V. Wirth, T. Blecha, L. Herc, L. Klocker, R. Linhart, K. Rendl, P. Sehnal, F. Steiner
This article deals with possibilities of the automatic testing of multimedia units. The aim of the work was to design and realize an automatic test system for a functional parameter measurement of multimedia units. The system was built up by the help of individual measuring devices and the designed multiplexer. The entire system is controlled by the control computer. For the control computer was necessary to create software to control and communicate with devices and multimedia unit itself. For making utility programs, the programming language Labview and Teststand software tool from National Instruments was chosen.
{"title":"Automatic testing of multimedia units","authors":"V. Wirth, T. Blecha, L. Herc, L. Klocker, R. Linhart, K. Rendl, P. Sehnal, F. Steiner","doi":"10.1109/ISSE.2012.6273074","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273074","url":null,"abstract":"This article deals with possibilities of the automatic testing of multimedia units. The aim of the work was to design and realize an automatic test system for a functional parameter measurement of multimedia units. The system was built up by the help of individual measuring devices and the designed multiplexer. The entire system is controlled by the control computer. For the control computer was necessary to create software to control and communicate with devices and multimedia unit itself. For making utility programs, the programming language Labview and Teststand software tool from National Instruments was chosen.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"210 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124911632","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273157
R. Schramm, A. Reinhardt, J. Franke
The present study aims to display new opportunities for flexible printed circuit boards (FPC) in electronic manufacturing by using biopolymers based on renewable materials as substrate material. Therefore, four different biopolymers, polyhydroxybutyrate (PHB), cellulose acetate (CA) and two different copolymers of polylactid acid and thermoplastic polyester elastomer (PLA+TPC), were processed with the standard process chain of the electronic manufacturing. Thereby, the main focus of attention was the thermal behavior during the hot embossing and reflow soldering in a vapor phase reflow soldering oven. Furthermore, manufactured FPCs were put in a temperature-humidity-test for 200 hours. The aim is to identify the weaknesses of current available biopolymers in order to improve future biopolymers for using in the electronic manufacturing.
{"title":"Capability of biopolymers in electronics manufacturing","authors":"R. Schramm, A. Reinhardt, J. Franke","doi":"10.1109/ISSE.2012.6273157","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273157","url":null,"abstract":"The present study aims to display new opportunities for flexible printed circuit boards (FPC) in electronic manufacturing by using biopolymers based on renewable materials as substrate material. Therefore, four different biopolymers, polyhydroxybutyrate (PHB), cellulose acetate (CA) and two different copolymers of polylactid acid and thermoplastic polyester elastomer (PLA+TPC), were processed with the standard process chain of the electronic manufacturing. Thereby, the main focus of attention was the thermal behavior during the hot embossing and reflow soldering in a vapor phase reflow soldering oven. Furthermore, manufactured FPCs were put in a temperature-humidity-test for 200 hours. The aim is to identify the weaknesses of current available biopolymers in order to improve future biopolymers for using in the electronic manufacturing.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116271621","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273091
S. Stoyanov, C. Best, M. Alam, C. Bailey, P. Tollafield, M. Parker, J. Scott
The use of microelectronics components with lead-free solder finishes on their terminations in high reliability and safety critical defence and aerospace equipment is associated with major long-term reliability issues due to tin-whisker growth phenomena. A potential solution to this problem is to “re-finish” the package terminations by removing the tin coating from the leads and replace with conventional tin-lead solder in a post-manufacturing process known as hot solder dip (HSD). This paper details a modelling approach to the thermo-mechanical characterisation of leaded components subjected to a double-dip HSD process. Transient thermal finite element analysis (FEA) is used to evaluate the temperature distribution and gradients in a QFP-type component and then used as thermal loads to predict the stress evolution in the package. The risk of thermally induced damage in the part at package level is assessed using the model predictions and compared with findings from electrical and CSAM tests undertaken on a pre- and post- refinished samples. It is concluded that in the instance of the studied part no thermo-mechanical damage is induced as a result of the HSD.
{"title":"Modelling and testing the impact of hot solder dip process on leaded components","authors":"S. Stoyanov, C. Best, M. Alam, C. Bailey, P. Tollafield, M. Parker, J. Scott","doi":"10.1109/ISSE.2012.6273091","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273091","url":null,"abstract":"The use of microelectronics components with lead-free solder finishes on their terminations in high reliability and safety critical defence and aerospace equipment is associated with major long-term reliability issues due to tin-whisker growth phenomena. A potential solution to this problem is to “re-finish” the package terminations by removing the tin coating from the leads and replace with conventional tin-lead solder in a post-manufacturing process known as hot solder dip (HSD). This paper details a modelling approach to the thermo-mechanical characterisation of leaded components subjected to a double-dip HSD process. Transient thermal finite element analysis (FEA) is used to evaluate the temperature distribution and gradients in a QFP-type component and then used as thermal loads to predict the stress evolution in the package. The risk of thermally induced damage in the part at package level is assessed using the model predictions and compared with findings from electrical and CSAM tests undertaken on a pre- and post- refinished samples. It is concluded that in the instance of the studied part no thermo-mechanical damage is induced as a result of the HSD.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132356231","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273139
P. Schnederle, M. Adamek, I. Szendiuch
An important part of the microelectronics manufacturing is the reflow process. Even though that the soldering have a long history, the process is still not completely described. Particular still discussed the introduction of the WEEE Directive 2003/108/EC standards and RoHS Directive 2002/95/EC got the soldering received into new areas. There is a space for new material compositions which do not contain lead. Furthermore, a new procedure process, adjusting of equipment and began to make greater use of nitrogen as protective gas. The aim is to compare the already proven commercial solder alloys on different carrier and evaluate more exactly the benefits of nitrogen atmosphere. The evaluation was performed for solder SAC, Sn100C and SnPb solder paste was used as reference. Type of substrates was printed circuit board FR-4 and ceramic substrate. Soldering conducted in atmosphere with different residual oxygen. Results of this paper may serve to increase the quality of soldering classical package as well as BGA and CSP package.
{"title":"Effect of nitrogen atmosphere on the soldering process for different types of lead-free solders","authors":"P. Schnederle, M. Adamek, I. Szendiuch","doi":"10.1109/ISSE.2012.6273139","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273139","url":null,"abstract":"An important part of the microelectronics manufacturing is the reflow process. Even though that the soldering have a long history, the process is still not completely described. Particular still discussed the introduction of the WEEE Directive 2003/108/EC standards and RoHS Directive 2002/95/EC got the soldering received into new areas. There is a space for new material compositions which do not contain lead. Furthermore, a new procedure process, adjusting of equipment and began to make greater use of nitrogen as protective gas. The aim is to compare the already proven commercial solder alloys on different carrier and evaluate more exactly the benefits of nitrogen atmosphere. The evaluation was performed for solder SAC, Sn100C and SnPb solder paste was used as reference. Type of substrates was printed circuit board FR-4 and ceramic substrate. Soldering conducted in atmosphere with different residual oxygen. Results of this paper may serve to increase the quality of soldering classical package as well as BGA and CSP package.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131270856","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273146
T. Vlad, D. Pitica, L. Man, J. Rajmond
This paper presents methods used to improve the teaching process applied in electronics, using the advantages of a complete educational platform. Also, this paper is focused both on maximizing the knowledge already acquired by the 1st year students and on exploitation of previous personal experiences. The purpose of using these methods is to establish an individualized path that would better highlight the specific skills of each student.
{"title":"Optimized methods for theoretical and practical training","authors":"T. Vlad, D. Pitica, L. Man, J. Rajmond","doi":"10.1109/ISSE.2012.6273146","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273146","url":null,"abstract":"This paper presents methods used to improve the teaching process applied in electronics, using the advantages of a complete educational platform. Also, this paper is focused both on maximizing the knowledge already acquired by the 1st year students and on exploitation of previous personal experiences. The purpose of using these methods is to establish an individualized path that would better highlight the specific skills of each student.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130005273","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273083
P. Evgenia, M. Pavel
The increasing complexity of technological processes has imposed considerable uncertainties and subjectivities in the risk analyses of these processes. The paper integrates the use of fuzzy logic and expert database with FMEA. Application of fuzzy sets theory on FMEA of a technological process. Analysis of the lead-free soldering process is based on fuzzy logic. The proposed fuzzy risk analysis approach is more flexible and more intelligent than the original risk analysis techniques. The paper shows case-study of fuzzy FMEA of a lead-free soldering.
{"title":"Fuzzy risk analysis approach test-case: Lead-free soldering process","authors":"P. Evgenia, M. Pavel","doi":"10.1109/ISSE.2012.6273083","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273083","url":null,"abstract":"The increasing complexity of technological processes has imposed considerable uncertainties and subjectivities in the risk analyses of these processes. The paper integrates the use of fuzzy logic and expert database with FMEA. Application of fuzzy sets theory on FMEA of a technological process. Analysis of the lead-free soldering process is based on fuzzy logic. The proposed fuzzy risk analysis approach is more flexible and more intelligent than the original risk analysis techniques. The paper shows case-study of fuzzy FMEA of a lead-free soldering.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125969092","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273159
M. Weilguni, M. Franz, N. Slyusar'
Thermoelectric generators (TEGs) are highly promising for energy harvesting applications [1]. Currently, TEGs are mainly utilized in self-sustaining sensor systems where small amounts of energy (milli-Watt-range) are sufficient. Since the efficiency of TEGs can be increased due to new materials and technologies they become interesting to be used in passenger cars as an alternative to the alternator [2, 3]. In these vehicles the thermal energy of the exhaust gas of the car engine could potentially provide the required energy. This paper presents the results of a feasibility study and the life cycle inventory of TEG modules that should replace the alternator of a passenger car. Within this life cycle inventory, the cradle-to-gate energy efforts are estimated.
{"title":"Feasibility study and life cycle energy balance of thermoelectric generator modules for automotive applications","authors":"M. Weilguni, M. Franz, N. Slyusar'","doi":"10.1109/ISSE.2012.6273159","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273159","url":null,"abstract":"Thermoelectric generators (TEGs) are highly promising for energy harvesting applications [1]. Currently, TEGs are mainly utilized in self-sustaining sensor systems where small amounts of energy (milli-Watt-range) are sufficient. Since the efficiency of TEGs can be increased due to new materials and technologies they become interesting to be used in passenger cars as an alternative to the alternator [2, 3]. In these vehicles the thermal energy of the exhaust gas of the car engine could potentially provide the required energy. This paper presents the results of a feasibility study and the life cycle inventory of TEG modules that should replace the alternator of a passenger car. Within this life cycle inventory, the cradle-to-gate energy efforts are estimated.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134580927","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273112
P. Krivic, F. Wenzl, C. Sommer, G. Langer, P. Pachler, H. Hoschopf, P. Fulmek, J. Nicolics
The reliability and long-term stability of solid-state lighting devices strongly depend on successful thermal management. It is well known that junction temperature instability negatively impacts the lightning properties of LED illuminators. However, for prediction of life time and longterm stability the temperature distribution also inside the color converter must be known. A deeper understanding of these demanding thermal issues is provided in our paper on the base of measurements and simulations also taking into account the spatial power loss distribution due to absorption of light and Stokes shift within the color converter. For this purpose 3-dimensional models were set-up and examined to thermally characterize high-power LED assemblies. Two different types of set-ups were investigated. Moreover, an efficient solution is presented where a junction-to-case thermal resistance below 10 K/W is achieved.
{"title":"Investigation of thermal properties of power LED illumination assemblies","authors":"P. Krivic, F. Wenzl, C. Sommer, G. Langer, P. Pachler, H. Hoschopf, P. Fulmek, J. Nicolics","doi":"10.1109/ISSE.2012.6273112","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273112","url":null,"abstract":"The reliability and long-term stability of solid-state lighting devices strongly depend on successful thermal management. It is well known that junction temperature instability negatively impacts the lightning properties of LED illuminators. However, for prediction of life time and longterm stability the temperature distribution also inside the color converter must be known. A deeper understanding of these demanding thermal issues is provided in our paper on the base of measurements and simulations also taking into account the spatial power loss distribution due to absorption of light and Stokes shift within the color converter. For this purpose 3-dimensional models were set-up and examined to thermally characterize high-power LED assemblies. Two different types of set-ups were investigated. Moreover, an efficient solution is presented where a junction-to-case thermal resistance below 10 K/W is achieved.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124702563","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 : 2012-05-09DOI: 10.1109/ISSE.2012.6273152
J. Grochowski, M. Guziewicz, R. Kruszka, M. Borysiewicz, K. Kopalko, A. Piotrowska
The aim of our work was to produce p-n heterojunction with the high level of optical transmission. P-type NiO and n-type ZnO:Al films deposited by magnetron sputtering were used to fabricate p-n diodes. These were thermally processed in Ar ambient at 400°C in order to obtain high optical transmission and better electrical characteristics. The best diode's parameters were rectifying ratio of 6.7·104 and reverse current at the level of 6·10-7A at -3 V of bias. The best obtained optical transmission of the bilayer was near 20% in the visual wavelength region.
{"title":"Fabrication and characterization of p-NiO/n-ZnO heterojunction towards transparent diode","authors":"J. Grochowski, M. Guziewicz, R. Kruszka, M. Borysiewicz, K. Kopalko, A. Piotrowska","doi":"10.1109/ISSE.2012.6273152","DOIUrl":"https://doi.org/10.1109/ISSE.2012.6273152","url":null,"abstract":"The aim of our work was to produce p-n heterojunction with the high level of optical transmission. P-type NiO and n-type ZnO:Al films deposited by magnetron sputtering were used to fabricate p-n diodes. These were thermally processed in Ar ambient at 400°C in order to obtain high optical transmission and better electrical characteristics. The best diode's parameters were rectifying ratio of 6.7·104 and reverse current at the level of 6·10-7A at -3 V of bias. The best obtained optical transmission of the bilayer was near 20% in the visual wavelength region.","PeriodicalId":277579,"journal":{"name":"2012 35th International Spring Seminar on Electronics Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129715170","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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