Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0264
Teodora Szasz, A. Basarab, M. Vaida, D. Kouamé
Nowadays the classical Delay-and-Sum (DAS) beamformer is extensively used in ultrasound imaging due to its low computational characteristics. However, it suffers from high sidelobe level, poor resolution and low contrast. An alternative is the Minimum-Variance (MV) beamformer which results in a higher image quality both in terms of spatial resolution and contrast. Even so, these benefits come at the expense of a higher computation complexity that limits its real-time capabilities. One solution that recently gained noticeable interest is the exploit of the sparsity of the scanned medium. Based on this assumption, we extend the DAS method to yield sparse results by using the Bayesian Information Criterion (BIC). Our realistic simulations demonstrate that the proposed beamforming (BF) method shows better performance than the classical DAS and MV in terms of lateral resolution, sidelobe reduction and contrast.
{"title":"Beamforming with sparse prior in ultrasound medical imaging","authors":"Teodora Szasz, A. Basarab, M. Vaida, D. Kouamé","doi":"10.1109/ULTSYM.2014.0264","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0264","url":null,"abstract":"Nowadays the classical Delay-and-Sum (DAS) beamformer is extensively used in ultrasound imaging due to its low computational characteristics. However, it suffers from high sidelobe level, poor resolution and low contrast. An alternative is the Minimum-Variance (MV) beamformer which results in a higher image quality both in terms of spatial resolution and contrast. Even so, these benefits come at the expense of a higher computation complexity that limits its real-time capabilities. One solution that recently gained noticeable interest is the exploit of the sparsity of the scanned medium. Based on this assumption, we extend the DAS method to yield sparse results by using the Bayesian Information Criterion (BIC). Our realistic simulations demonstrate that the proposed beamforming (BF) method shows better performance than the classical DAS and MV in terms of lateral resolution, sidelobe reduction and contrast.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115129969","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0517
Andrew Mathieson, D. DeAngelis
Lead-based piezoceramics are currently the most widely used transduction material in power ultrasonic applications. Directives such as the Restriction of Hazardous Substances (RoHS and RoHS2) regulate the sale of electrical and electronic equipment containing hazardous substances, such as lead, entering the European marketplace. However, lead-based piezoceramics have been exempt due to the lack of a genuine lead-free equivalent. Lead-free piezoceramics were first developed in the 1950s, however their relatively poor properties when compared to PZT left them largely neglected until the implementation of the European directive. This study investigates the incorporation of a modern lead-free piezoceramic, a variant of bismuth sodium titanate (BNT), into a commercial power ultrasonic transducer used in semiconductor wire bonding. It is reported that a device containing BNT was capable of forming wire bonds, and that the lead-free transducer exhibited properties that could make them suitable in other power ultrasonic applications.
{"title":"Feasibility of lead-free piezoceramic based power ultrasonic transducers","authors":"Andrew Mathieson, D. DeAngelis","doi":"10.1109/ULTSYM.2014.0517","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0517","url":null,"abstract":"Lead-based piezoceramics are currently the most widely used transduction material in power ultrasonic applications. Directives such as the Restriction of Hazardous Substances (RoHS and RoHS2) regulate the sale of electrical and electronic equipment containing hazardous substances, such as lead, entering the European marketplace. However, lead-based piezoceramics have been exempt due to the lack of a genuine lead-free equivalent. Lead-free piezoceramics were first developed in the 1950s, however their relatively poor properties when compared to PZT left them largely neglected until the implementation of the European directive. This study investigates the incorporation of a modern lead-free piezoceramic, a variant of bismuth sodium titanate (BNT), into a commercial power ultrasonic transducer used in semiconductor wire bonding. It is reported that a device containing BNT was capable of forming wire bonds, and that the lead-free transducer exhibited properties that could make them suitable in other power ultrasonic applications.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115496218","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0498
James Robertson, B. Cox, B. Treeby
Effective transcranial transmission of focused ultrasound is desirable for various therapeutic applications. Time-reversal (TR) focusing based on numerical simulations of ultrasound propagation can be used to correct for the aberrating skull layer. For weakly heterogeneous media, k-space and pseudospectral time domain (PSTD) methods have been shown to have increased accuracy and efficiency compared to the finite-difference time domain (FDTD) methods typically used in TR. However, their suitability for highly heterogeneous, transcranial simulations is less clear. Here, this is established in terms of spatial and temporal sampling requirements through numerical testing and comparison with FDTD schemes. PSTD schemes are shown to give equal or better accuracy compared to FDTD schemes for modelling propagation through tissue-realistic heterogeneities, which, combined with the reduction in numerical dispersion obtained with k-space correction, recommends them for use in simulated TR.
{"title":"Quantifying numerical errors in the simulation of transcranial ultrasound using pseudospectral methods","authors":"James Robertson, B. Cox, B. Treeby","doi":"10.1109/ULTSYM.2014.0498","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0498","url":null,"abstract":"Effective transcranial transmission of focused ultrasound is desirable for various therapeutic applications. Time-reversal (TR) focusing based on numerical simulations of ultrasound propagation can be used to correct for the aberrating skull layer. For weakly heterogeneous media, k-space and pseudospectral time domain (PSTD) methods have been shown to have increased accuracy and efficiency compared to the finite-difference time domain (FDTD) methods typically used in TR. However, their suitability for highly heterogeneous, transcranial simulations is less clear. Here, this is established in terms of spatial and temporal sampling requirements through numerical testing and comparison with FDTD schemes. PSTD schemes are shown to give equal or better accuracy compared to FDTD schemes for modelling propagation through tissue-realistic heterogeneities, which, combined with the reduction in numerical dispersion obtained with k-space correction, recommends them for use in simulated TR.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115638271","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0019
M. Iwaki, J. Tsutsumi, M. Ueda, Y. Satoh
The co-design of a SAW duplexer and a low-noise amplifier (LNA) for reducing the total noise figure of the Rx chain in the RF front-end of current multi-band cellular handsets is presented in this paper. The co-design procedure is proposed and one case study for the UMTS Band2 is demonstrated. The key point of the co-design is designing a duplexer and an LNA at the optimum impedance, instead of the standard 50 Ω impedance interface, while taking the matching circuit loss into account. The possibility of reducing the total noise figure is shown in the case study simulation.
{"title":"Co-design of SAW duplexer and LNA in RF transceiver IC for reducing total noise figure in RF front-end of cellular systems","authors":"M. Iwaki, J. Tsutsumi, M. Ueda, Y. Satoh","doi":"10.1109/ULTSYM.2014.0019","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0019","url":null,"abstract":"The co-design of a SAW duplexer and a low-noise amplifier (LNA) for reducing the total noise figure of the Rx chain in the RF front-end of current multi-band cellular handsets is presented in this paper. The co-design procedure is proposed and one case study for the UMTS Band2 is demonstrated. The key point of the co-design is designing a duplexer and an LNA at the optimum impedance, instead of the standard 50 Ω impedance interface, while taking the matching circuit loss into account. The possibility of reducing the total noise figure is shown in the case study simulation.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115719261","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0197
H. Hirano, T. Samoto, Tetsuya Kimura, Masahiro Inaba, K. Hashimoto, T. Matsumura, K. Hikichi, M. Kadota, M. Esashi, Shuji Tanaka
Cognitive radio technology on TV white spaces has been promoted worldwide to solve the spectrum shortage problem due to the explosive increase in personal communication systems such as smartphones. One of the most difficult challenges to utilize TV white space for personal use is the miniaturization of frequency and bandwidth tunable filters to select vacant TV channels. We have developed a one-chip bandwidth tunable filter by wafer-level transfer-integration of BaSrTiO3 (BST) film varactors and surface acoustic wave (SAW) resonators on a lithium tantalate wafer. The 3 dB bandwidth of the bandwidth tunable filter is tuned between 3.25 MHz and 6.25 MHz by applying 7V to the varactors, while the center frequency was constant at 1.004 GHz, as designed. These filters were installed in our developed prototype cognitive radio systems based on the IEEE802.11af draft and successfully demonstrated wireless LAN communication on TV frequency band.
{"title":"Bandwidth-tunable SAW filter based on wafer-level transfer-integration of BaSrTiO3 film for wireless LAN system using TV white space","authors":"H. Hirano, T. Samoto, Tetsuya Kimura, Masahiro Inaba, K. Hashimoto, T. Matsumura, K. Hikichi, M. Kadota, M. Esashi, Shuji Tanaka","doi":"10.1109/ULTSYM.2014.0197","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0197","url":null,"abstract":"Cognitive radio technology on TV white spaces has been promoted worldwide to solve the spectrum shortage problem due to the explosive increase in personal communication systems such as smartphones. One of the most difficult challenges to utilize TV white space for personal use is the miniaturization of frequency and bandwidth tunable filters to select vacant TV channels. We have developed a one-chip bandwidth tunable filter by wafer-level transfer-integration of BaSrTiO3 (BST) film varactors and surface acoustic wave (SAW) resonators on a lithium tantalate wafer. The 3 dB bandwidth of the bandwidth tunable filter is tuned between 3.25 MHz and 6.25 MHz by applying 7V to the varactors, while the center frequency was constant at 1.004 GHz, as designed. These filters were installed in our developed prototype cognitive radio systems based on the IEEE802.11af draft and successfully demonstrated wireless LAN communication on TV frequency band.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124416154","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0549
M. Schiffner, G. Schmitz
We introduced the fast multipole method (FMM) into our concept for plane wave pulse-echo ultrasound imaging (UI) to reduce the memory consumption and the computational costs associated with the numerical solution of the underlying regularized linear inverse scattering problem (ISP). For an example of typical size and in comparison to the conventional approach, we showed that the FMM requires less than 0.25% of the memory and less than 24% of the number of complex-valued multiplications. The FMM thus enables the numerical solution of the regularized (e.g. by compressed sensing) linear ISP on standard personal computers. It significantly improves the applicability of inverse scattering strategies in practical UI.
{"title":"Pulse-echo ultrasound imaging combining compressed sensing and the fast multipole method","authors":"M. Schiffner, G. Schmitz","doi":"10.1109/ULTSYM.2014.0549","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0549","url":null,"abstract":"We introduced the fast multipole method (FMM) into our concept for plane wave pulse-echo ultrasound imaging (UI) to reduce the memory consumption and the computational costs associated with the numerical solution of the underlying regularized linear inverse scattering problem (ISP). For an example of typical size and in comparison to the conventional approach, we showed that the FMM requires less than 0.25% of the memory and less than 24% of the number of complex-valued multiplications. The FMM thus enables the numerical solution of the regularized (e.g. by compressed sensing) linear ISP on standard personal computers. It significantly improves the applicability of inverse scattering strategies in practical UI.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123158750","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0099
Kyle Morrison, G. Keilman, P. Kaczkowski
This paper describes a series of high intensity focused ultrasound (HIFU) phased array transducers with a single Archimedean spiral close packed element arrangement on a spherical surface extending from the central axis outward. Simulation and measurement reveal using the spiral element arrangement on a spherical bowl reduces grating side lobes while maximizing power density at the focus.
{"title":"Single archimedean spiral close packed phased array HIFU","authors":"Kyle Morrison, G. Keilman, P. Kaczkowski","doi":"10.1109/ULTSYM.2014.0099","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0099","url":null,"abstract":"This paper describes a series of high intensity focused ultrasound (HIFU) phased array transducers with a single Archimedean spiral close packed element arrangement on a spherical surface extending from the central axis outward. Simulation and measurement reveal using the spiral element arrangement on a spherical bowl reduces grating side lobes while maximizing power density at the focus.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124258265","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0134
Junseob Shin, Yu Chen, M. Nguyen, J. Yen
Dual Apodization with Cross-correlation (DAX) is a novel beamforming technique that utilizes a pair of complementary receive apodizations for clutter suppression in ultrasound imaging. The effectiveness of DAX in-vivo is often reduced because of the strong reverberation clutter signals caused by near-field structures. In this work, we propose a modified version of DAX, known as Multi-Apodization with Cross-correlation (MAX), which suppresses reverberation clutter in a highly robust manner by utilizing multiple pairs of receive apodizations followed by normalized cross-correlation. Our simulation, experimental and initial clinical results show that MAX achieves a large improvement over DAX in terms of image contrast and shows great potential for more accurate diagnosis in clinics.
双消位交叉相关波束形成技术是利用一对互补的接收消位来抑制超声成像中的杂波的一种新型波束形成技术。近场结构引起的强混响杂波信号往往会降低DAX在体内的有效性。在这项工作中，我们提出了一种改进版本的DAX，称为多重apodiization with Cross-correlation (MAX)，它通过利用多对接收apodiization之后的归一化互相关，以高度鲁棒的方式抑制混响杂波。我们的仿真、实验和初步临床结果表明，MAX在图像对比度方面比DAX有很大的提高，在临床上具有更准确的诊断潜力。
{"title":"Robust ultrasonic reverberation clutter suppression using Multi-Apodization with Cross-correlation","authors":"Junseob Shin, Yu Chen, M. Nguyen, J. Yen","doi":"10.1109/ULTSYM.2014.0134","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0134","url":null,"abstract":"Dual Apodization with Cross-correlation (DAX) is a novel beamforming technique that utilizes a pair of complementary receive apodizations for clutter suppression in ultrasound imaging. The effectiveness of DAX in-vivo is often reduced because of the strong reverberation clutter signals caused by near-field structures. In this work, we propose a modified version of DAX, known as Multi-Apodization with Cross-correlation (MAX), which suppresses reverberation clutter in a highly robust manner by utilizing multiple pairs of receive apodizations followed by normalized cross-correlation. Our simulation, experimental and initial clinical results show that MAX achieves a large improvement over DAX in terms of image contrast and shows great potential for more accurate diagnosis in clinics.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120982665","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0652
X. Jian, Zhile Han, Yongjia Xiang, Zhangjian Li, Yaoyao Cui
Usually focused transducers have acoustical lens or large concave surface in order to generate focused high intensity ultrasound beam. Therefore these traditional focusing transducers are commonly large in size and long in focal length, which are not suitable for interventional ultrasound imaging or therapy. For solving this problem, in this paper, a micromachined self-focusing piezoelectric composite ultrasonic transducer was designed and evaluated. The theoretical analysis was deduced based on the electromechanical response of piezoelectric composites and theory of Fresnel half-wave band interference. This self-focusing transducer has many advantages, including micro size, short focal length, low acoustic impedance, high electromechanical coupling coefficient. Besides these, because it was based on micro-electromechanical systems, the fabrication process precision is high and reliable. These results hold good potential for interventional ultrasound therapy or imaging applications.
{"title":"Micromachined self-focusing piezoelectric composite ultrasonic transducer","authors":"X. Jian, Zhile Han, Yongjia Xiang, Zhangjian Li, Yaoyao Cui","doi":"10.1109/ULTSYM.2014.0652","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0652","url":null,"abstract":"Usually focused transducers have acoustical lens or large concave surface in order to generate focused high intensity ultrasound beam. Therefore these traditional focusing transducers are commonly large in size and long in focal length, which are not suitable for interventional ultrasound imaging or therapy. For solving this problem, in this paper, a micromachined self-focusing piezoelectric composite ultrasonic transducer was designed and evaluated. The theoretical analysis was deduced based on the electromechanical response of piezoelectric composites and theory of Fresnel half-wave band interference. This self-focusing transducer has many advantages, including micro size, short focal length, low acoustic impedance, high electromechanical coupling coefficient. Besides these, because it was based on micro-electromechanical systems, the fabrication process precision is high and reliable. These results hold good potential for interventional ultrasound therapy or imaging applications.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127364299","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 : 2014-10-23DOI: 10.1109/ULTSYM.2014.0484
Jungsoon Kim, Jihee Jung, M. Bae, Moojoon Kim, Kang-lyeol Ha, Mincheol Chu
The single nano particle state was obtained by using a ultrasonic humidifier. To control the surface tension, the concentration of methanol changed in the suspension of TiO2 nano particle. The collecting effect was investigated by measuring the particle size distribution. As the surface tension was decreased by increasing the concentration of methanol, the particle size at the peak of distribution was decreased and the number of particles per unit volume was increased. The nano particles with intended size could be collected by controlling the surface tension of the suspension.
{"title":"Single nano particle collecting by using ultrasonic humidifier","authors":"Jungsoon Kim, Jihee Jung, M. Bae, Moojoon Kim, Kang-lyeol Ha, Mincheol Chu","doi":"10.1109/ULTSYM.2014.0484","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0484","url":null,"abstract":"The single nano particle state was obtained by using a ultrasonic humidifier. To control the surface tension, the concentration of methanol changed in the suspension of TiO2 nano particle. The collecting effect was investigated by measuring the particle size distribution. As the surface tension was decreased by increasing the concentration of methanol, the particle size at the peak of distribution was decreased and the number of particles per unit volume was increased. The nano particles with intended size could be collected by controlling the surface tension of the suspension.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127527156","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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