Pub Date : 2004-06-06DOI: 10.1109/MWSYM.2004.1338947
D. Pasalic, R. Vahldieck
The time-domain TLM method was used for the rigorous analysis of traveling wave photodiodes. The calculation of bandwidth included effects like velocity mismatch, finite saturation velocity of the photogenerated carriers and RF and optical attenuation constant. The obtained data were compared with experiments and data obtained by other numerical techniques. An excellent agreement was observed with FDTD results, while comparing to the equivalent circuit data, our results were in much better agreement with experiment. The effects of the optical attenuation coefficient on the photodetector's bandwidth were investigated as well.
{"title":"Application of the TLM method for the characterization of traveling wave photodetectors","authors":"D. Pasalic, R. Vahldieck","doi":"10.1109/MWSYM.2004.1338947","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1338947","url":null,"abstract":"The time-domain TLM method was used for the rigorous analysis of traveling wave photodiodes. The calculation of bandwidth included effects like velocity mismatch, finite saturation velocity of the photogenerated carriers and RF and optical attenuation constant. The obtained data were compared with experiments and data obtained by other numerical techniques. An excellent agreement was observed with FDTD results, while comparing to the equivalent circuit data, our results were in much better agreement with experiment. The effects of the optical attenuation coefficient on the photodetector's bandwidth were investigated as well.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128377821","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1336047
N. Nishijima, Juo-Jung Hung, Gabriel M. Rebeiz
This paper describes a novel structure for an electro-static actuated RF-MEMS metal-contact switch which achieves low-voltage actuations. Using a cantilever and placing a pull-down electrode outside the contact dimples, the actuation voltage can be reduced greatly while keeping a high contact force and restoration force. The simulation results show that the novel design operates around 20 V and produces a contact force of >200 /spl mu/N per contact, and a restoration force of >115 /spl mu/N per contact. The measured actuation voltage is 20-30 V which is higher than the designed value, and is thought to be caused by stress induced deflection. The measured RF isolation is 29 dB (Cu=28 fF) and the measured insertion loss is 0.2 dB (Rs=2.1 /spl Omega/) at 2 GHz.
本文介绍了一种新型的静电驱动RF-MEMS金属触点开关结构，可实现低压驱动。使用悬臂梁并在接触凹窝外放置下拉电极，可以大大降低驱动电压，同时保持较高的接触力和恢复力。仿真结果表明，该设计在20 V左右工作，每个触点产生>200 /spl mu/N的接触力，每个触点产生>115 /spl mu/N的恢复力。实测的驱动电压为20 ~ 30v，高于设计值，认为是由应力引起的偏转引起的。在2 GHz时，测量到的射频隔离为29 dB (Cu=28 fF)，插入损耗为0.2 dB (Rs=2.1 /spl ω /)。
{"title":"A low-voltage high contact force RF-MEMS switch","authors":"N. Nishijima, Juo-Jung Hung, Gabriel M. Rebeiz","doi":"10.1109/MWSYM.2004.1336047","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1336047","url":null,"abstract":"This paper describes a novel structure for an electro-static actuated RF-MEMS metal-contact switch which achieves low-voltage actuations. Using a cantilever and placing a pull-down electrode outside the contact dimples, the actuation voltage can be reduced greatly while keeping a high contact force and restoration force. The simulation results show that the novel design operates around 20 V and produces a contact force of >200 /spl mu/N per contact, and a restoration force of >115 /spl mu/N per contact. The measured actuation voltage is 20-30 V which is higher than the designed value, and is thought to be caused by stress induced deflection. The measured RF isolation is 29 dB (Cu=28 fF) and the measured insertion loss is 0.2 dB (Rs=2.1 /spl Omega/) at 2 GHz.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128572745","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339052
K. Andersson, C. Fager, P. Linnér, H. Zirath
A statistical approach to the problem of parameter extraction of small-signal FET models is presented. This approach makes it possible to accurately assess parameter estimates and their variance and covariance, due to measurement uncertainties, without utilizing time consuming Monte-Carlo simulations. The method presented uses a maximum likelihood estimation with the widely used cold-FET technique to determine the parasitic elements and their covariance from two different gate bias conditions. These are thereafter used to perform a corresponding maximum likelihood estimation of the intrinsic elements from an active bias condition. Thereby, maximum information available from the measurements are brought into determining the model parameters as accurate as possible. The accuracy of the intrinsic and parasitic covariance are validated using Monte-Carlo simulations.
{"title":"Statistical estimation of small-signal FET model parameters and their covariance","authors":"K. Andersson, C. Fager, P. Linnér, H. Zirath","doi":"10.1109/MWSYM.2004.1339052","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339052","url":null,"abstract":"A statistical approach to the problem of parameter extraction of small-signal FET models is presented. This approach makes it possible to accurately assess parameter estimates and their variance and covariance, due to measurement uncertainties, without utilizing time consuming Monte-Carlo simulations. The method presented uses a maximum likelihood estimation with the widely used cold-FET technique to determine the parasitic elements and their covariance from two different gate bias conditions. These are thereafter used to perform a corresponding maximum likelihood estimation of the intrinsic elements from an active bias condition. Thereby, maximum information available from the measurements are brought into determining the model parameters as accurate as possible. The accuracy of the intrinsic and parasitic covariance are validated using Monte-Carlo simulations.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128263937","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339186
Chang-Ho Lee, B. Banerjee, J. Laskar
In this paper, we present new architectures for three kinds of RF switches (DPDT, DP4T, 4P4T) with very simple control logics and high power handling capabilities. Implementation of DPDT, DP4T, and 4P4T switch matrix for multi-input-multi-output (MIMO) applications is demonstrated with measurements. The suggested DPDT, DP4T, and 4P4T switch architectures require only one, two and three control lines, respectively, regardless of semiconductor technology. The developed DPDT switch demonstrates 1.0 dB of insertion loss, 19 dB of isolation, and 31 dBm of input P0.1 dB, 34.5 dBm of input P1 dB in 3/0 V operation at 5.8 GHz. The DP4T, 4P4T switches exhibit 1.8 dB, 2.8 dB of insertion loss, and 23/37 dB, 20/35/55 dB of isolation, respectively, and 31 dBm of input P0.1 dB, 35 dBm of input P1 dB in 3/0 V operation at 5.8 GHz. The MMICs are developed in a commercial 0.25-/spl mu/m GaAs pHEMT process. These switch architectures are preferable for the Si-based processes because the substrate vias are not required due to their generic topologies. To the best of our knowledge, this is the first report on the simple architectures for RF switch matrix for MIMO applications.
{"title":"Novel T/R switch architectures for MIMO applications","authors":"Chang-Ho Lee, B. Banerjee, J. Laskar","doi":"10.1109/MWSYM.2004.1339186","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339186","url":null,"abstract":"In this paper, we present new architectures for three kinds of RF switches (DPDT, DP4T, 4P4T) with very simple control logics and high power handling capabilities. Implementation of DPDT, DP4T, and 4P4T switch matrix for multi-input-multi-output (MIMO) applications is demonstrated with measurements. The suggested DPDT, DP4T, and 4P4T switch architectures require only one, two and three control lines, respectively, regardless of semiconductor technology. The developed DPDT switch demonstrates 1.0 dB of insertion loss, 19 dB of isolation, and 31 dBm of input P0.1 dB, 34.5 dBm of input P1 dB in 3/0 V operation at 5.8 GHz. The DP4T, 4P4T switches exhibit 1.8 dB, 2.8 dB of insertion loss, and 23/37 dB, 20/35/55 dB of isolation, respectively, and 31 dBm of input P0.1 dB, 35 dBm of input P1 dB in 3/0 V operation at 5.8 GHz. The MMICs are developed in a commercial 0.25-/spl mu/m GaAs pHEMT process. These switch architectures are preferable for the Si-based processes because the substrate vias are not required due to their generic topologies. To the best of our knowledge, this is the first report on the simple architectures for RF switch matrix for MIMO applications.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127058972","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339168
R. Hajji, J. Shumaker, E. Camargo
This paper presents a large-signal model developed for a packaged 28 V GaAs FET power device, suitable for high-power Base Station Applications. The model is capable of predicting external load and source impedances that enable the device to provide desired power and linearity (IM3 and IM5) performance. It also takes into account the device temperature difference between the unit-cell transistor and the whole multi-cell device. Therefore, design cycle of high power PA modules are shortened and so is the development of internally matched devices for other frequencies. The paper shows an application example for a P/sub 1dB/ of 80 W.
{"title":"28 V high-power GaAs FET large-signal modeling achieves power and linearity prediction","authors":"R. Hajji, J. Shumaker, E. Camargo","doi":"10.1109/MWSYM.2004.1339168","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339168","url":null,"abstract":"This paper presents a large-signal model developed for a packaged 28 V GaAs FET power device, suitable for high-power Base Station Applications. The model is capable of predicting external load and source impedances that enable the device to provide desired power and linearity (IM3 and IM5) performance. It also takes into account the device temperature difference between the unit-cell transistor and the whole multi-cell device. Therefore, design cycle of high power PA modules are shortened and so is the development of internally matched devices for other frequencies. The paper shows an application example for a P/sub 1dB/ of 80 W.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129920631","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1335886
T. Tanaka, K. Nishikawa, M. Aikawa
In this paper, very miniaturized 90/spl deg/ hybrid circuit using quasi-distributed TFMS line is described. In a planar formed conventional MMIC's, the passive circuits such as 90/spl deg/ branch-line hybrid has occupied a large chip area. Therefore, it is strongly desired that the chip area is more miniaturized. For increasing integration level, the three-dimensional (3D) MMIC has been developed. In the 3D MMICs, meander-like lines are realized easily and many metal-insulator-metal (MIM) capacitors can be loaded on transmission lines. By the 3D MMIC topology, a transmission line composed of high impedance thin film microstrip (TFMS) lines and MIM capacitors are realized easily. This type TFMS transmission line is called "quasi-distributed thin film microstrip (QD-TFMS) line". A very small 90/spl deg/ branch-like hybrid using the QD-TFMS lines is realized. The fabricated 9/spl deg/ branch-like hybrid size is more than 80% smaller than that of conventional one compose of meander-like transmission lines in area.
{"title":"Miniaturized 90/spl deg/ hybrid circuit using quasi-distributed TFMS line","authors":"T. Tanaka, K. Nishikawa, M. Aikawa","doi":"10.1109/MWSYM.2004.1335886","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1335886","url":null,"abstract":"In this paper, very miniaturized 90/spl deg/ hybrid circuit using quasi-distributed TFMS line is described. In a planar formed conventional MMIC's, the passive circuits such as 90/spl deg/ branch-line hybrid has occupied a large chip area. Therefore, it is strongly desired that the chip area is more miniaturized. For increasing integration level, the three-dimensional (3D) MMIC has been developed. In the 3D MMICs, meander-like lines are realized easily and many metal-insulator-metal (MIM) capacitors can be loaded on transmission lines. By the 3D MMIC topology, a transmission line composed of high impedance thin film microstrip (TFMS) lines and MIM capacitors are realized easily. This type TFMS transmission line is called \"quasi-distributed thin film microstrip (QD-TFMS) line\". A very small 90/spl deg/ branch-like hybrid using the QD-TFMS lines is realized. The fabricated 9/spl deg/ branch-like hybrid size is more than 80% smaller than that of conventional one compose of meander-like transmission lines in area.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130006658","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1335854
Ming-Fong Lei, Pei-Si Wu, Tian-Wei Huang, Huei Wang
A W-band monolithic sub-harmonically pumped (SHP) resistive mixer was designed and fabricated using a standard 0.15/spl mu/m PHEMT process. A nonlinear model featuring modified drain-current characteristics was developed and used in circuit simulation. A small chip size of 1.5 /spl times/ 1.0 mm/sup 2/ was achieved by using a transformer as a LO balun. Measured results of this circuit showed 14-18 dB conversion losses from 75 to 88 GHz, and agree well with simulation. Analysis on circuit imbalance shows that the phase imbalance of the balun is the dominant factor on LO isolation, and the conversion loss is quite robust to all circuit imbalances.
{"title":"Design and analysis of a miniature W-band MMIC subharmonically pumped resistive mixer","authors":"Ming-Fong Lei, Pei-Si Wu, Tian-Wei Huang, Huei Wang","doi":"10.1109/MWSYM.2004.1335854","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1335854","url":null,"abstract":"A W-band monolithic sub-harmonically pumped (SHP) resistive mixer was designed and fabricated using a standard 0.15/spl mu/m PHEMT process. A nonlinear model featuring modified drain-current characteristics was developed and used in circuit simulation. A small chip size of 1.5 /spl times/ 1.0 mm/sup 2/ was achieved by using a transformer as a LO balun. Measured results of this circuit showed 14-18 dB conversion losses from 75 to 88 GHz, and agree well with simulation. Analysis on circuit imbalance shows that the phase imbalance of the balun is the dominant factor on LO isolation, and the conversion loss is quite robust to all circuit imbalances.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130156505","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339088
J. Komiak, R. Actis, W. Kong, K. Nichols
Design and performance of state of the art wideband MMICs for Intelligent RF Microsystems are described. These include a SDLVA with the widest reported bandwidth of 5 to 20 GHz, an SGA with DC to greater than 20 GHz frequency response, a four bit 5 to 16 GHz SDGVGA and a 256 state vector modulator covering 6 to 16 GHz.
{"title":"Broadband SDLVA, SGA, SDGVGA, and vector modulator elements for Intelligent RF Microsystems","authors":"J. Komiak, R. Actis, W. Kong, K. Nichols","doi":"10.1109/MWSYM.2004.1339088","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339088","url":null,"abstract":"Design and performance of state of the art wideband MMICs for Intelligent RF Microsystems are described. These include a SDLVA with the widest reported bandwidth of 5 to 20 GHz, an SGA with DC to greater than 20 GHz frequency response, a four bit 5 to 16 GHz SDGVGA and a 256 state vector modulator covering 6 to 16 GHz.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"252 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132387767","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1339144
Shengdong Li, Zhen Yu, S. Yen, P. Burke, W. Tang
We present the first microwave measurements of the dynamical impedance of an individual, electrically contacted single walled carbon nanotube. Both semiconducting and metallic nanotubes are measured. Using a semiconducting nanotube, we construct an LC nano-resonator at 2 GHz. The Q of the nano-resonator can be tuned by varying the back-gate voltage on the nanotube. In contrast, the Q of a resonator fabricated with a metallic nanotube is insensitive to the back-gate voltage. This represents the first step towards passive microwave signal processing components based on carbon nanotubes.
{"title":"Carbon nanotube GHz nano-resonator","authors":"Shengdong Li, Zhen Yu, S. Yen, P. Burke, W. Tang","doi":"10.1109/MWSYM.2004.1339144","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1339144","url":null,"abstract":"We present the first microwave measurements of the dynamical impedance of an individual, electrically contacted single walled carbon nanotube. Both semiconducting and metallic nanotubes are measured. Using a semiconducting nanotube, we construct an LC nano-resonator at 2 GHz. The Q of the nano-resonator can be tuned by varying the back-gate voltage on the nanotube. In contrast, the Q of a resonator fabricated with a metallic nanotube is insensitive to the back-gate voltage. This represents the first step towards passive microwave signal processing components based on carbon nanotubes.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132415376","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 : 2004-06-06DOI: 10.1109/MWSYM.2004.1335827
M. Heins, J. Carroll, M. Kao, J. Delaney, C. Campbell
Two X-band LNA ICs have been demonstrated using a 0.15 /spl mu/m metamorphic GaAs HEMT technology. The amplifiers have an average noise figure of 0.5 dB and power gain greater than 31 dB from 7-10 GHz. A current-shared version had gain flatness better than 1 dB, return losses greater than 11 dB, and power consumption of 42 mW. A high linearity version has an output third-order intercept point greater than 20.5 dBm from 6-12 GHz.
{"title":"X-band GaAs mHEMT LNAs with 0.5 dB noise figure","authors":"M. Heins, J. Carroll, M. Kao, J. Delaney, C. Campbell","doi":"10.1109/MWSYM.2004.1335827","DOIUrl":"https://doi.org/10.1109/MWSYM.2004.1335827","url":null,"abstract":"Two X-band LNA ICs have been demonstrated using a 0.15 /spl mu/m metamorphic GaAs HEMT technology. The amplifiers have an average noise figure of 0.5 dB and power gain greater than 31 dB from 7-10 GHz. A current-shared version had gain flatness better than 1 dB, return losses greater than 11 dB, and power consumption of 42 mW. A high linearity version has an output third-order intercept point greater than 20.5 dBm from 6-12 GHz.","PeriodicalId":334675,"journal":{"name":"2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129243709","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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