Pub Date : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805446
P. Spinney, Scott D. Collins, Rosemary L. Smith
The patterning of carbon nanostructures by electron beam stimulated oxidation is described. Sputter deposited carbon thin films and carbon nanotubes are locally oxidized in a scanning electron microscope using injected water vapor. The resulting structures are examined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrical resistance obtained post-processing is comparable to as-deposited values. Etched linewidths on the order of 20nm are demonstrated along with sub-2nm wide carbon wires.
{"title":"Electron Beam Stimulated Oxidation of Carbon (EBSOC)","authors":"P. Spinney, Scott D. Collins, Rosemary L. Smith","doi":"10.1109/MEMSYS.2009.4805446","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805446","url":null,"abstract":"The patterning of carbon nanostructures by electron beam stimulated oxidation is described. Sputter deposited carbon thin films and carbon nanotubes are locally oxidized in a scanning electron microscope using injected water vapor. The resulting structures are examined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrical resistance obtained post-processing is comparable to as-deposited values. Etched linewidths on the order of 20nm are demonstrated along with sub-2nm wide carbon wires.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116112178","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805334
M. Ikeuchi, Ryosuke Tane, Muneaki Fukuoka, K. Ikuta
This is the first report on a nanofibrous surface patterning process using nano-meshed polymer microcapsules for biological applications. The nano-meshed microcapsules were formed using a method named phase separation assisted electrospray. Features of the nano-meshed microcapsules were found to be tunable by adjusting process conditions. Contrary to non-woven mats formed of continuous nanofibers via conventional electrospinning, nano-meshed microcapsule reported herein enabled a single step nanofibrous surface patterning by electrostatic focusing following the microcapsule formation. The biodegradable polylactic acid made microcapsules were patterned onto a glass substrate with up to 500¿m resolution and human hepatocyte cells were cultured on the patterned areas to confirm biocompatibility of the microcapsule.
{"title":"Nanofibrous Surface Patterning using Nano-Meshed Microcapsules Induced by Phase Seperation Assisted Electrospray","authors":"M. Ikeuchi, Ryosuke Tane, Muneaki Fukuoka, K. Ikuta","doi":"10.1109/MEMSYS.2009.4805334","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805334","url":null,"abstract":"This is the first report on a nanofibrous surface patterning process using nano-meshed polymer microcapsules for biological applications. The nano-meshed microcapsules were formed using a method named phase separation assisted electrospray. Features of the nano-meshed microcapsules were found to be tunable by adjusting process conditions. Contrary to non-woven mats formed of continuous nanofibers via conventional electrospinning, nano-meshed microcapsule reported herein enabled a single step nanofibrous surface patterning by electrostatic focusing following the microcapsule formation. The biodegradable polylactic acid made microcapsules were patterned onto a glass substrate with up to 500¿m resolution and human hepatocyte cells were cultured on the patterned areas to confirm biocompatibility of the microcapsule.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"334 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116529229","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805465
S. Couderc, B.J. Kim, T. Someya
This article covers investigations on an original, almost fully biodegradable and flexible mechanical switch device fabricated from cellulose composite. The cellulose films, mainly composed of microfibrils, revealed a high surface roughness and poor dielectric properties making them unsuitable substrates for electronic applications. By coating the cellulose film with a specific polyimide, these drawbacks were overcome. The mechanical switch was operated through the deflection of an electrostatically actuated cantilever beam. Its displacement, induced by the electrostatic force, was validated and the switch ON state detection was performed for an actuation voltage of 55 V and for a beam-substrate distance around 30 ¿m.
{"title":"Cellulose-Based Composite as a Raw Material for Flexible and Ultra-Lightweight Mechanical Switch Devices","authors":"S. Couderc, B.J. Kim, T. Someya","doi":"10.1109/MEMSYS.2009.4805465","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805465","url":null,"abstract":"This article covers investigations on an original, almost fully biodegradable and flexible mechanical switch device fabricated from cellulose composite. The cellulose films, mainly composed of microfibrils, revealed a high surface roughness and poor dielectric properties making them unsuitable substrates for electronic applications. By coating the cellulose film with a specific polyimide, these drawbacks were overcome. The mechanical switch was operated through the deflection of an electrostatically actuated cantilever beam. Its displacement, induced by the electrostatic force, was validated and the switch ON state detection was performed for an actuation voltage of 55 V and for a beam-substrate distance around 30 ¿m.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122287003","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805524
I. Reines, B. Pillans, Gabriel M. Rebeiz
We present the design, fabrication, and measurement of an RF MEMS (Radio Frequency Micro-Electromechanical System) switched capacitor that exhibits reduced sensitivity to residual stress and temperature. The device is based on a circularly symmetric geometry with arc-type springs placed between the anchors and suspended beam. This design compensates for the effects of the residual biaxial stress in the beam, resulting in a pull-in voltage slope versus temperature of only -50 mV/ °C from -5 °C to 95 °C. Reducing the device sensitivity to residual stress improves the performance uniformity on a wafer-scale, and from wafer-to-wafer lots.
{"title":"A Stress-Tolerant Temperature-Stable RF MEMS Switched Capacitor","authors":"I. Reines, B. Pillans, Gabriel M. Rebeiz","doi":"10.1109/MEMSYS.2009.4805524","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805524","url":null,"abstract":"We present the design, fabrication, and measurement of an RF MEMS (Radio Frequency Micro-Electromechanical System) switched capacitor that exhibits reduced sensitivity to residual stress and temperature. The device is based on a circularly symmetric geometry with arc-type springs placed between the anchors and suspended beam. This design compensates for the effects of the residual biaxial stress in the beam, resulting in a pull-in voltage slope versus temperature of only -50 mV/ °C from -5 °C to 95 °C. Reducing the device sensitivity to residual stress improves the performance uniformity on a wafer-scale, and from wafer-to-wafer lots.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122823355","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805494
Hyunjoo Lee, K. Park, P. Cristman, O. Oralkan, M. Kupnik, B. Khuri-Yakub
We present 17.5-MHz and 42.7-MHz low-noise Colpitts oscillators employing capacitive micromachined ultrasonic transducers (CMUTs), each composed of a thousand resonator cells electrically connected in parallel. The massive parallelism lowers the motional impedance, and thus, reduces frequency noise and provides better matching to low-noise oscillator topologies. The 42.7-MHz oscillator achieved a phase noise of -105 dBc/Hz and -148 dBc/Hz at offset frequencies of 1 kHz and 1 MHz, respectively in air. The performance is comparable to MEMS oscillators based on resonators with high Q in vacuum. The lowest Allan deviation of the oscillator was measured to be 4.7 × 10-9 implying a mass resolution of 0.96 attogram per membrane. In addition, using the 17.5-MHz CMUT resonator, the performance of the Colpitts topology is compared to that of the amplifier based oscillator topology.
{"title":"A Low-Noise Oscillator based on a Multi-Membrane CMUT for High Sensitivity Resonant Chemical Sensors","authors":"Hyunjoo Lee, K. Park, P. Cristman, O. Oralkan, M. Kupnik, B. Khuri-Yakub","doi":"10.1109/MEMSYS.2009.4805494","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805494","url":null,"abstract":"We present 17.5-MHz and 42.7-MHz low-noise Colpitts oscillators employing capacitive micromachined ultrasonic transducers (CMUTs), each composed of a thousand resonator cells electrically connected in parallel. The massive parallelism lowers the motional impedance, and thus, reduces frequency noise and provides better matching to low-noise oscillator topologies. The 42.7-MHz oscillator achieved a phase noise of -105 dBc/Hz and -148 dBc/Hz at offset frequencies of 1 kHz and 1 MHz, respectively in air. The performance is comparable to MEMS oscillators based on resonators with high Q in vacuum. The lowest Allan deviation of the oscillator was measured to be 4.7 × 10-9 implying a mass resolution of 0.96 attogram per membrane. In addition, using the 17.5-MHz CMUT resonator, the performance of the Colpitts topology is compared to that of the amplifier based oscillator topology.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123010968","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805339
G. Villanueva, O. Vázquez-Mena, C. Hibert, J. Brugger
This paper reports the feasibility of the fabrication of high aspect ratio structures on substrates via dry etching through a stencil mask placed onto the sample. It demonstrates the possibility to use standard equipment and processes with this novel masking technique, which allows the patterning of fragile and pre-structured surfaces, and avoids the use of resist or additional coating of the sample, reducing costs and processing time. Aspect ratios as high as 13:1 and pattern transfer with a gap of 100 ¿m are demonstrated.
{"title":"Direct Etching of High Aspect Ratio Structures Through a Stencil","authors":"G. Villanueva, O. Vázquez-Mena, C. Hibert, J. Brugger","doi":"10.1109/MEMSYS.2009.4805339","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805339","url":null,"abstract":"This paper reports the feasibility of the fabrication of high aspect ratio structures on substrates via dry etching through a stencil mask placed onto the sample. It demonstrates the possibility to use standard equipment and processes with this novel masking technique, which allows the patterning of fragile and pre-structured surfaces, and avoids the use of resist or additional coating of the sample, reducing costs and processing time. Aspect ratios as high as 13:1 and pattern transfer with a gap of 100 ¿m are demonstrated.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114127797","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805500
K. Noda, K. Matsumoto, I. Shimoyama
We propose a tactile sensor with standing cantilevers embedded in viscous liquid. The viscous liquid was covered with an elastic body. Since the micro cantilevers were kept free in the liquid, they can detect large shear forces without damaging. When shear forces were applied to the sensor surface, they deform the elastic body and the viscous liquid. Since the standing cantilevers follow deformations of viscous liquid, shear forces can be detected with resistance changes of the cantilevers. If the shear force was kept constant, the cantilevers in liquid return to their initial posture. From this mechanism, the proposed sensor can detect the change of shear forces without damaging. Since the standing cantilever in single liquid filter detect the force applied to its surface. It becomes difficult to detect the contact position with the proposed sensor. Therefore, we arranged channel in the liquid filter to control the liquid flow. By arranging standing cantilevers into the channel, the cantilever's resistance changes with the distance from the contact position. In this paper, we measured the relationship between the contact position and the resistance changes of the cantilevers arranged in channel.
{"title":"Flexible Tactile Sensor Sheet with Liquid Filter for Shear Force Detection","authors":"K. Noda, K. Matsumoto, I. Shimoyama","doi":"10.1109/MEMSYS.2009.4805500","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805500","url":null,"abstract":"We propose a tactile sensor with standing cantilevers embedded in viscous liquid. The viscous liquid was covered with an elastic body. Since the micro cantilevers were kept free in the liquid, they can detect large shear forces without damaging. When shear forces were applied to the sensor surface, they deform the elastic body and the viscous liquid. Since the standing cantilevers follow deformations of viscous liquid, shear forces can be detected with resistance changes of the cantilevers. If the shear force was kept constant, the cantilevers in liquid return to their initial posture. From this mechanism, the proposed sensor can detect the change of shear forces without damaging. Since the standing cantilever in single liquid filter detect the force applied to its surface. It becomes difficult to detect the contact position with the proposed sensor. Therefore, we arranged channel in the liquid filter to control the liquid flow. By arranging standing cantilevers into the channel, the cantilever's resistance changes with the distance from the contact position. In this paper, we measured the relationship between the contact position and the resistance changes of the cantilevers arranged in channel.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117021355","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805416
M. D. De Volder, F. Ceyssens, D. Reynaerts, R. Puers
To improve the force output of microactuators, this work focuses on actuators driven by pressurized gasses or liquids. Despite their well known ability to generate high actuation forces, hydraulic actuators remain uncommon in microsystems. This is both due to the difficulty of fabricating these microactuators with the existing micromachining processes and to the lack of adequate microseals. This paper describes how to overcome these limitations with a combination of anisotropic micromachining, UV definable polymers and low temperature bonding. The functionality of these actuators is proven by extensive measurements which showed that actuation forces of 0.1 N can be achieved for actuators with an active cross-section of 0.15 mm2. This is an order of magnitude higher than what is reported for classic MEMS actuators of similar size.
{"title":"Design and Characterisation of a Hydraulic Microactuator Fabricated by Lithography","authors":"M. D. De Volder, F. Ceyssens, D. Reynaerts, R. Puers","doi":"10.1109/MEMSYS.2009.4805416","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805416","url":null,"abstract":"To improve the force output of microactuators, this work focuses on actuators driven by pressurized gasses or liquids. Despite their well known ability to generate high actuation forces, hydraulic actuators remain uncommon in microsystems. This is both due to the difficulty of fabricating these microactuators with the existing micromachining processes and to the lack of adequate microseals. This paper describes how to overcome these limitations with a combination of anisotropic micromachining, UV definable polymers and low temperature bonding. The functionality of these actuators is proven by extensive measurements which showed that actuation forces of 0.1 N can be achieved for actuators with an active cross-section of 0.15 mm2. This is an order of magnitude higher than what is reported for classic MEMS actuators of similar size.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129733650","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805357
H. Sato, Y. Peeri, E. Baghoomian, C. W. Berry, M. Maharbiz
We present the first report of radio control of a cyborg beetle in free-flight. The microsystem (Figs. 1,2) consisted of a radio-frequency receiver assembly, a micro battery and a live giant flower beetle platform (Mecynorhina polyphemus or Mecynorhina torquata). The assembly had six electrode stimulators implanted into the left and right optic lobes, brain, posterior pronotum (counter electrode), right and left basalar flight muscles. Initiation and cessation of flight were accomplished by optic lobe stimulation while muscular stimulation of either right or left basalar flight muscles (referenced to the posterior pronotum electrode) elicited left or right turns, respectively. Flight commands were wirelessly transferred to the beetle-mounted system (running BeetleBrain v1.0 code) via an RF transmitter operated by a laptop running custom software (BeetleCo mmander v1.0) through a USB/Serial interface.
{"title":"Radio-Controlled Cyborg Beetles: A Radio-Frequency System for Insect Neural Flight Control","authors":"H. Sato, Y. Peeri, E. Baghoomian, C. W. Berry, M. Maharbiz","doi":"10.1109/MEMSYS.2009.4805357","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805357","url":null,"abstract":"We present the first report of radio control of a cyborg beetle in free-flight. The microsystem (Figs. 1,2) consisted of a radio-frequency receiver assembly, a micro battery and a live giant flower beetle platform (Mecynorhina polyphemus or Mecynorhina torquata). The assembly had six electrode stimulators implanted into the left and right optic lobes, brain, posterior pronotum (counter electrode), right and left basalar flight muscles. Initiation and cessation of flight were accomplished by optic lobe stimulation while muscular stimulation of either right or left basalar flight muscles (referenced to the posterior pronotum electrode) elicited left or right turns, respectively. Flight commands were wirelessly transferred to the beetle-mounted system (running BeetleBrain v1.0 code) via an RF transmitter operated by a laptop running custom software (BeetleCo mmander v1.0) through a USB/Serial interface.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128459965","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 : 2009-03-27DOI: 10.1109/MEMSYS.2009.4805333
B. Davidson, Y. Chang, D. Seghete, S. George, V. Bright
In this paper we present a novel low temperature, CMOS compatible, direct top-down nano-fabrication process employing ALD tungsten (WALD) as a structural material for nano-electro-mechanical systems (NEMS). Using this process doubly clamped suspended NEMS devices have been successfully fabricated and demonstrated. The devices have been observed to operate comparably to 2-terminal electrostatic carbon nanotube (CNT) switches, and MEMS tunneling devices. A lifetime in excess of 660,500 cycles has been observed under low-current-limited operating conditions. Under these conditions the device behavior is stable, reproducible and hysterisis free, resembling that of MEMS tunneling devices.
{"title":"Atomic Layer Deposition (ALD) Tungsten NEMS Devices via a Novel Top-Down Approach","authors":"B. Davidson, Y. Chang, D. Seghete, S. George, V. Bright","doi":"10.1109/MEMSYS.2009.4805333","DOIUrl":"https://doi.org/10.1109/MEMSYS.2009.4805333","url":null,"abstract":"In this paper we present a novel low temperature, CMOS compatible, direct top-down nano-fabrication process employing ALD tungsten (WALD) as a structural material for nano-electro-mechanical systems (NEMS). Using this process doubly clamped suspended NEMS devices have been successfully fabricated and demonstrated. The devices have been observed to operate comparably to 2-terminal electrostatic carbon nanotube (CNT) switches, and MEMS tunneling devices. A lifetime in excess of 660,500 cycles has been observed under low-current-limited operating conditions. Under these conditions the device behavior is stable, reproducible and hysterisis free, resembling that of MEMS tunneling devices.","PeriodicalId":187850,"journal":{"name":"2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130670893","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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