Pub Date : 2010-05-28DOI: 10.1109/ARFTG.2010.5496321
M. Myslinski, F. Verbeyst, M. vanden Bossche, D. Schreurs
In this paper we report for the first time on order reduction applied to S-functions behavioral models. The most dominant model parameters are selected based on the relative uncertainty of their estimated values evaluated against a threshold value. The selection procedure is performed on the same measurement data that is used to extract the model and obtained using a large-signal network analyzer. High level of model order reduction, achieved without any substantial loss of the prediction accuracy, is demonstrated on S-functions extracted for a packaged pHEMT device.
{"title":"S-functions behavioral model order reduction based on narrowband modulated large-signal network analyzer measurements","authors":"M. Myslinski, F. Verbeyst, M. vanden Bossche, D. Schreurs","doi":"10.1109/ARFTG.2010.5496321","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496321","url":null,"abstract":"In this paper we report for the first time on order reduction applied to S-functions behavioral models. The most dominant model parameters are selected based on the relative uncertainty of their estimated values evaluated against a threshold value. The selection procedure is performed on the same measurement data that is used to extract the model and obtained using a large-signal network analyzer. High level of model order reduction, achieved without any substantial loss of the prediction accuracy, is demonstrated on S-functions extracted for a packaged pHEMT device.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114993966","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496323
B. Shoulders, Ken Wong
We perform noise figure calibrations on a noise measurement receiver using the following techniques: A “Y-factor” technique that uses two source impedance states (a characterized “excess” noise source and a low reflection room temperature termination) in both the calibration and the measurement, a “Vector Cold Noise (VCN)” technique that uses multiple room temperature source impedance states in both the calibration and the measurement along with a characterized “excess” noise source in the calibration and a “Scalar Cold Noise” technique that uses the same calibration as the VCN technique, but uses only a low reflection room temperature source impedance state in the measurement. Following each calibration, we verify the calibrations after the method of Randa et al. and present the results along with uncertainties derived from a Monet Carlo simulation
{"title":"Comparison of noise figure calibration and measurement techniques using noise figure verification techniques","authors":"B. Shoulders, Ken Wong","doi":"10.1109/ARFTG.2010.5496323","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496323","url":null,"abstract":"We perform noise figure calibrations on a noise measurement receiver using the following techniques: A “Y-factor” technique that uses two source impedance states (a characterized “excess” noise source and a low reflection room temperature termination) in both the calibration and the measurement, a “Vector Cold Noise (VCN)” technique that uses multiple room temperature source impedance states in both the calibration and the measurement along with a characterized “excess” noise source in the calibration and a “Scalar Cold Noise” technique that uses the same calibration as the VCN technique, but uses only a low reflection room temperature source impedance state in the measurement. Following each calibration, we verify the calibrations after the method of Randa et al. and present the results along with uncertainties derived from a Monet Carlo simulation","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122630652","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496315
D. Humphreys, M. Harper, M. Salter
We have developed a calibration technique for Vector Signal Analyzers (VSA) that provides traceability to primary standards. This technique has been implemented using standard commercial equipment. A multisine signal generator provides detailed magnitude and phase stimulus over the instrument bandwidth and a Digital Sampling Oscilloscope (DSO) measures the same multisine waveform. Traceability is provided via the DSO, calibrated against the primary standard (Electro-Optic Sampler). The VSA can be characterized over its full-bandwidth (magnitude and phase) at any operating frequency. The reproducibility of three different multi-sine measurements, averaged over an 80 MHz bandwidth was 3.4% (power) and 1.3 degrees (phase).
{"title":"Traceable calibration of Vector Signal Analyzers","authors":"D. Humphreys, M. Harper, M. Salter","doi":"10.1109/ARFTG.2010.5496315","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496315","url":null,"abstract":"We have developed a calibration technique for Vector Signal Analyzers (VSA) that provides traceability to primary standards. This technique has been implemented using standard commercial equipment. A multisine signal generator provides detailed magnitude and phase stimulus over the instrument bandwidth and a Digital Sampling Oscilloscope (DSO) measures the same multisine waveform. Traceability is provided via the DSO, calibrated against the primary standard (Electro-Optic Sampler). The VSA can be characterized over its full-bandwidth (magnitude and phase) at any operating frequency. The reproducibility of three different multi-sine measurements, averaged over an 80 MHz bandwidth was 3.4% (power) and 1.3 degrees (phase).","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117195511","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496318
M. B. Ayed, S. Boumaiza
This paper proposes an experimental analysis focusing on the sensitivity of three behavioral models, Memory Polynomial (MP), Augmented Hammerstein (AH) and the two hidden layers artificial neural networks (2HLANN) to the characteristics of the input signal driving the power amplifier (PA) to be linearized. The analysis is carried out by changing separately each signal characteristic, respectively the peak to average power ratio (PAPR), the Probability density function (PDF), and the modulation bandwidth and assess the sensitivity of the DPD to that change. When used to linearise a 250 Watt peak-envelop-power Doherty PA, the considered models showed relatively small sensitivity to the variation of these signal characteristics. Yet, the 2HLANN was found to be the most robust model with excellent linearization capabilities.
{"title":"Experimental sensitivity analysis of multi-standard power amplifiers nonlinear characterization under modulated signals","authors":"M. B. Ayed, S. Boumaiza","doi":"10.1109/ARFTG.2010.5496318","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496318","url":null,"abstract":"This paper proposes an experimental analysis focusing on the sensitivity of three behavioral models, Memory Polynomial (MP), Augmented Hammerstein (AH) and the two hidden layers artificial neural networks (2HLANN) to the characteristics of the input signal driving the power amplifier (PA) to be linearized. The analysis is carried out by changing separately each signal characteristic, respectively the peak to average power ratio (PAPR), the Probability density function (PDF), and the modulation bandwidth and assess the sensitivity of the DPD to that change. When used to linearise a 250 Watt peak-envelop-power Doherty PA, the considered models showed relatively small sensitivity to the variation of these signal characteristics. Yet, the 2HLANN was found to be the most robust model with excellent linearization capabilities.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125303235","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496325
J. Martens
Practically, many network analyzer measurements (both large signal and small signal) are performed at frequencies other than those where the calibration was performed in order to save time and effort. Typically, the error terms are simply interpolated in some way to calibrate at the new frequencies. Under what circumstances and how this interpolation is done can significantly affect the uncertainties of the measurement. This paper explores the characteristics of this interpolative error and how its impact can sometimes be assessed. Of particular note is that the hardware dependence of this effect is considerably larger than for many other components of uncertainty.
{"title":"Some effects of error term interpolation on network analyzer uncertainties","authors":"J. Martens","doi":"10.1109/ARFTG.2010.5496325","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496325","url":null,"abstract":"Practically, many network analyzer measurements (both large signal and small signal) are performed at frequencies other than those where the calibration was performed in order to save time and effort. Typically, the error terms are simply interpolated in some way to calibrate at the new frequencies. Under what circumstances and how this interpolation is done can significantly affect the uncertainties of the measurement. This paper explores the characteristics of this interpolative error and how its impact can sometimes be assessed. Of particular note is that the hardware dependence of this effect is considerably larger than for many other components of uncertainty.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"6 9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116869092","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496333
Rui Zhang, Feng Zhou, Long-qing Guo, Nan Wang
Digital modulation signal is the main bearer of modern information transmission; modulation error parameters include Error Vector Magnitude (EVM), MagErr and PhaseErr. However, there are problems for metrology of digital modulation error: first, the signal source and vector signal analyzers calibrates each other, and forms a closed-loop, the calibration is not traceable. Second, digital modulation error are set in the “0” point in calibration. To solve the problems, we propose a new method: use combination of two CW, analog AM or PM signal, to construct an “equivalent MPSK signals” with certain modulation error. The equivalent MPSK signals' EvmRms, EvmPeak, MagErrRms, MagErrPeak, PhaseErrRms and PhaseErrPeak is are solely decided by power ratio of two CW, or by AM depth or PM phase deviation, and can be calculated accurately, and are continuously adjustable within a wide range. Experiment shows that the method is effective. This has established a standard signal with digital modulation error, it's could be used to calibrate vector demodulation functions of vector signal analyzer (VSA) and wireless communications tester.
{"title":"Calibration standards for digital modulation error based on CW, AM or PM signal","authors":"Rui Zhang, Feng Zhou, Long-qing Guo, Nan Wang","doi":"10.1109/ARFTG.2010.5496333","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496333","url":null,"abstract":"Digital modulation signal is the main bearer of modern information transmission; modulation error parameters include Error Vector Magnitude (EVM), MagErr and PhaseErr. However, there are problems for metrology of digital modulation error: first, the signal source and vector signal analyzers calibrates each other, and forms a closed-loop, the calibration is not traceable. Second, digital modulation error are set in the “0” point in calibration. To solve the problems, we propose a new method: use combination of two CW, analog AM or PM signal, to construct an “equivalent MPSK signals” with certain modulation error. The equivalent MPSK signals' EvmRms, EvmPeak, MagErrRms, MagErrPeak, PhaseErrRms and PhaseErrPeak is are solely decided by power ratio of two CW, or by AM depth or PM phase deviation, and can be calculated accurately, and are continuously adjustable within a wide range. Experiment shows that the method is effective. This has established a standard signal with digital modulation error, it's could be used to calibrate vector demodulation functions of vector signal analyzer (VSA) and wireless communications tester.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127281987","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496336
S. Albahrani, A. Parker
The influence of the non-ideal response of the pulse-amplifier on the trap and self-heating dynamics, and hence, on the drain-current transient in a GaN HEMT is studied with new trap and self-heating models. It is shown that the study of the trap and self-heating dynamics requires a proper correction technique that accounts for the change in trap-potential, trap time-constant and thermal response due to the non-ideal response of the pulse-amplifier. Several post-measurement data correction techniques are discussed and shown to be incapable of predicting the true drain-current transient. A pre-measurement terminal correction technique using a new version of the pulse measurement system is used to solve the problem.
{"title":"Impact of the pulse-amplifier slew-rate on the pulsed-IV measurement of GaN HEMTs","authors":"S. Albahrani, A. Parker","doi":"10.1109/ARFTG.2010.5496336","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496336","url":null,"abstract":"The influence of the non-ideal response of the pulse-amplifier on the trap and self-heating dynamics, and hence, on the drain-current transient in a GaN HEMT is studied with new trap and self-heating models. It is shown that the study of the trap and self-heating dynamics requires a proper correction technique that accounts for the change in trap-potential, trap time-constant and thermal response due to the non-ideal response of the pulse-amplifier. Several post-measurement data correction techniques are discussed and shown to be incapable of predicting the true drain-current transient. A pre-measurement terminal correction technique using a new version of the pulse measurement system is used to solve the problem.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129642207","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496338
M. Odyniec
This paper addresses measurements of relative timing of irregularly and differently shaped pulses (by which we mean signals that are zero beyond a finite interval). For such pulses the usual time reference points become useless: rising edges may change their slopes and shapes, and maxima might split. We propose a definition of the time reference applicable to smooth but otherwise arbitrary pulses. It is applicable to signal scaling, simplifies the covariance matrix (of parameters' error estimates) and yields an effective analytic estimate of timing error.
{"title":"Time reference for measurements of arbitrarily shaped pulses","authors":"M. Odyniec","doi":"10.1109/ARFTG.2010.5496338","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496338","url":null,"abstract":"This paper addresses measurements of relative timing of irregularly and differently shaped pulses (by which we mean signals that are zero beyond a finite interval). For such pulses the usual time reference points become useless: rising edges may change their slopes and shapes, and maxima might split. We propose a definition of the time reference applicable to smooth but otherwise arbitrary pulses. It is applicable to signal scaling, simplifies the covariance matrix (of parameters' error estimates) and yields an effective analytic estimate of timing error.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126749848","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496322
Y. Ko, P. Roblin, S. Myoung, J. Strahler, F. de Groote, J. Teyssier
A new testbed was developed with an LSNA to perform multi-harmonic broadband measurements for periodically modulated signals with bandwidth exceeding the IF receiver bandwidth of the LSNA. This testbed is intended for characterizing PAs using periodically modulated (multitone) signals often referred as multisines. Multisine signals can be synthesized to approximate the CCDF and PAPR of digitally modulated signals such as WiMAX and LTE (Long Term Evolution). In the experiment conducted a multisine with 13 tones distributed over 15 MHz was used which provided a PAPR of 6 dB. Using this excitation, the nonlinear response of a 80 W Doherty GaN PA at 2.16 GHz was characterized over a 80 MHz bandwidth. Inband signal distortion and spectral regrowth were recorded in the 63 tones measurement over the 80 MHz measurement bandwidth targeted at both the fundamental and second harmonic. This increased measurement bandwidth enables one to characterize the nonlinear vector response of the PA in its 3rd and 5th order inter-modulation bands at the fundamental frequency. The broadband vector results at the second harmonic obtained in the same measurements provides additional invaluable information for the multi-harmonic optimization of the efficiency of the Doherty PA under test. It is believed that the multi-harmonic broadband vector characterization capabilities provided by the reported testbed should assist with the development and verification of multi-harmonic behavioral models for wideband modulated signals.
研制了一种新的测试平台，用于对带宽超过中频接收机带宽的周期性调制信号进行多谐波宽带测量。该试验台用于使用周期性调制(多音)信号(通常称为多音信号)来表征PAs。多正弦信号的合成可以近似于WiMAX和LTE(长期演进)等数字调制信号的CCDF和PAPR。在进行的实验中，使用了分布在15 MHz以上的13个音调的多重正弦，其PAPR为6 dB。在此激励下，80w Doherty GaN PA在2.16 GHz的80mhz带宽上的非线性响应特性得到了表征。在针对基频和次谐波的80 MHz测量带宽的63音调测量中记录了带内信号失真和频谱再生。这种增加的测量带宽使人们能够在基频下表征PA在其3阶和5阶互调频带中的非线性矢量响应。在相同的测量中获得的二谐波宽带矢量结果为被测Doherty PA的多谐波效率优化提供了额外的宝贵信息。本文认为，所述试验台提供的多谐波宽带矢量表征能力将有助于宽带调制信号的多谐波行为模型的开发和验证。
{"title":"Multi-harmonic broadband measurements using an large signal network analyzer","authors":"Y. Ko, P. Roblin, S. Myoung, J. Strahler, F. de Groote, J. Teyssier","doi":"10.1109/ARFTG.2010.5496322","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496322","url":null,"abstract":"A new testbed was developed with an LSNA to perform multi-harmonic broadband measurements for periodically modulated signals with bandwidth exceeding the IF receiver bandwidth of the LSNA. This testbed is intended for characterizing PAs using periodically modulated (multitone) signals often referred as multisines. Multisine signals can be synthesized to approximate the CCDF and PAPR of digitally modulated signals such as WiMAX and LTE (Long Term Evolution). In the experiment conducted a multisine with 13 tones distributed over 15 MHz was used which provided a PAPR of 6 dB. Using this excitation, the nonlinear response of a 80 W Doherty GaN PA at 2.16 GHz was characterized over a 80 MHz bandwidth. Inband signal distortion and spectral regrowth were recorded in the 63 tones measurement over the 80 MHz measurement bandwidth targeted at both the fundamental and second harmonic. This increased measurement bandwidth enables one to characterize the nonlinear vector response of the PA in its 3rd and 5th order inter-modulation bands at the fundamental frequency. The broadband vector results at the second harmonic obtained in the same measurements provides additional invaluable information for the multi-harmonic optimization of the efficiency of the Doherty PA under test. It is believed that the multi-harmonic broadband vector characterization capabilities provided by the reported testbed should assist with the development and verification of multi-harmonic behavioral models for wideband modulated signals.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132965643","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 : 2010-05-28DOI: 10.1109/ARFTG.2010.5496340
Thomas Y. Wu, S. W. Chua, Y. L. Lu
The phase noise effect on microwave attenuation precision measurement using a lock-in amplifier (LIA) is studied. A frequency domain phase noise modeling is used to analyse the phase sensitive detection made by the LIA. The error bound for the magnitude and phase of LIA measurement has been established. The theoretical prediction of the maximum magnitude and phase fluctuation in LIA output agrees with the measured data quite well. This analysis is important for estimating the maximum attenuation measurement error caused by the phase noise of microwave sources and its uncertainty contribution to microwave attenuation measurement.
{"title":"Analysis of phase noise effect on microwave attenuation precision measurement using a heterodyne receiver","authors":"Thomas Y. Wu, S. W. Chua, Y. L. Lu","doi":"10.1109/ARFTG.2010.5496340","DOIUrl":"https://doi.org/10.1109/ARFTG.2010.5496340","url":null,"abstract":"The phase noise effect on microwave attenuation precision measurement using a lock-in amplifier (LIA) is studied. A frequency domain phase noise modeling is used to analyse the phase sensitive detection made by the LIA. The error bound for the magnitude and phase of LIA measurement has been established. The theoretical prediction of the maximum magnitude and phase fluctuation in LIA output agrees with the measured data quite well. This analysis is important for estimating the maximum attenuation measurement error caused by the phase noise of microwave sources and its uncertainty contribution to microwave attenuation measurement.","PeriodicalId":221794,"journal":{"name":"75th ARFTG Microwave Measurement Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116678418","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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