Pub Date : 2000-01-23DOI: 10.1109/MEMSYS.2000.838549
F. Kawai, P. Cusin, S. Konishi
A pneumatic balloon is applied to actuate a thin flexible end-effector. The pneumatic balloon actuator is fabricated on a cantilever for the flexible end-effector. The end-effector bends when the pneumatic balloon swells. Pneumatic balloon actuators provide large displacements, high forces, and flexible structures. The following trials aiming to implement microdevices have been estimated through prototyping. Diced silicon ribs are employed so as to keep a desired shape and patterned heaters are estimated for a pressure supply based on a phase transformation. A conveyance system is composed of distributed end effectors for our demonstration. A manipulation of a glass plate by the developed system is successfully operated.
{"title":"Thin flexible end-effector using pneumatic balloon actuator","authors":"F. Kawai, P. Cusin, S. Konishi","doi":"10.1109/MEMSYS.2000.838549","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838549","url":null,"abstract":"A pneumatic balloon is applied to actuate a thin flexible end-effector. The pneumatic balloon actuator is fabricated on a cantilever for the flexible end-effector. The end-effector bends when the pneumatic balloon swells. Pneumatic balloon actuators provide large displacements, high forces, and flexible structures. The following trials aiming to implement microdevices have been estimated through prototyping. Diced silicon ribs are employed so as to keep a desired shape and patterned heaters are estimated for a pressure supply based on a phase transformation. A conveyance system is composed of distributed end effectors for our demonstration. A manipulation of a glass plate by the developed system is successfully operated.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"105 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120814727","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838494
Zhen Yang, H. Goto, M. Matsumoto, R. Maeda
This paper describes the design, fabrication and evaluation of an active micromixer. Mixing occurs directly from ultrasonic vibration. The intended use of the device was for integrated micro chemical synthesis systems or for micro total analysis systems. The pattern of inlets, outlet and mixing chamber were formed in glass. The whole flow path was encapsulated by anodic bonding of a Si wafer to the glass. A diaphragm (6 mm/spl times/6 mm/spl times/0.15 mm) was etched on the Si side for oscillation. The ultrasonic vibration originated from a bulk piezoelectric PZT ceramic (5 mm/spl times/4 mm/spl times/0.15 mm), which was excited by a 60 kHz square wave at 50 V (peak-to-peak). Liquids were mixed in a chamber (6 mm/spl times/6 mm/spl times/0.06 mm) with the Si oscillating diaphragm driven by the PZT. A solution of uranine and water were used to evaluate the mixing effectiveness. The entire process was recorded using a fluorescent microscope equipped with digital camera. The laminar flows of uranine solution (5 /spl mu/l/min) and water (5 /spl mu/l/min) were mixed effectively when the PZT was excited.
{"title":"Ultrasonic micromixer for microfluidic systems","authors":"Zhen Yang, H. Goto, M. Matsumoto, R. Maeda","doi":"10.1109/MEMSYS.2000.838494","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838494","url":null,"abstract":"This paper describes the design, fabrication and evaluation of an active micromixer. Mixing occurs directly from ultrasonic vibration. The intended use of the device was for integrated micro chemical synthesis systems or for micro total analysis systems. The pattern of inlets, outlet and mixing chamber were formed in glass. The whole flow path was encapsulated by anodic bonding of a Si wafer to the glass. A diaphragm (6 mm/spl times/6 mm/spl times/0.15 mm) was etched on the Si side for oscillation. The ultrasonic vibration originated from a bulk piezoelectric PZT ceramic (5 mm/spl times/4 mm/spl times/0.15 mm), which was excited by a 60 kHz square wave at 50 V (peak-to-peak). Liquids were mixed in a chamber (6 mm/spl times/6 mm/spl times/0.06 mm) with the Si oscillating diaphragm driven by the PZT. A solution of uranine and water were used to evaluate the mixing effectiveness. The entire process was recorded using a fluorescent microscope equipped with digital camera. The laminar flows of uranine solution (5 /spl mu/l/min) and water (5 /spl mu/l/min) were mixed effectively when the PZT was excited.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129140175","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838542
Byeungleul Lee, C. Oh, Soo Lee, Y. Oh, K. Chun
This paper proposes an INS (Inertial Navigation System) grade, surface micro-machined differential resonant accelerometer (DRXL) by using the epitaxially grown thick polysilicon process. This proposed DRXL device produces a differential digital output upon an applied acceleration, and the principle is a gap-dependent electrical stiffness variation of the electrostatic resonator with torsion beam structures. Using this new operating concept, we designed, fabricated and tested the proposed device. The final device was fabricated by using the wafer level vacuum packaging process. The hermetic sealing cap structure was made of Pyrex 7740 glass with Ti layer as gettering material, and this cap wafer was anodically bonded with the polysilicon wafer at vacuum ambience. The measured Q-factor of the vacuum packaged DRXL was about 1/spl times/10/sup 3/ and the estimated inner pressure was about 200[mTorr]. We also achieved 73[Hz] output frequency change per unit G(9.8 m/s/sup c/) input with 12,716[Hz] nominal resonant frequency.
{"title":"A vacuum packaged differential resonant accelerometer using gap sensitive electrostatic stiffness changing effect","authors":"Byeungleul Lee, C. Oh, Soo Lee, Y. Oh, K. Chun","doi":"10.1109/MEMSYS.2000.838542","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838542","url":null,"abstract":"This paper proposes an INS (Inertial Navigation System) grade, surface micro-machined differential resonant accelerometer (DRXL) by using the epitaxially grown thick polysilicon process. This proposed DRXL device produces a differential digital output upon an applied acceleration, and the principle is a gap-dependent electrical stiffness variation of the electrostatic resonator with torsion beam structures. Using this new operating concept, we designed, fabricated and tested the proposed device. The final device was fabricated by using the wafer level vacuum packaging process. The hermetic sealing cap structure was made of Pyrex 7740 glass with Ti layer as gettering material, and this cap wafer was anodically bonded with the polysilicon wafer at vacuum ambience. The measured Q-factor of the vacuum packaged DRXL was about 1/spl times/10/sup 3/ and the estimated inner pressure was about 200[mTorr]. We also achieved 73[Hz] output frequency change per unit G(9.8 m/s/sup c/) input with 12,716[Hz] nominal resonant frequency.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127849758","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838484
O. Tabata, S. Konishi, P. Cusin, Y. Ito, F. Kawai, S. Hirai, S. Kawamura
This paper reports a device with tunable bending stiffness realized by microfabrication technology. Based on the newly proposed principles, two types of devices whose bending stiffness were controlled by electrostatic force and pneumatic force were fabricated. From the analysis and experiments, the feasibility of the proposed principles were confirmed and the performances of the prototyped devices were demonstrated.
{"title":"Microfabricated tunable bending stiffness device","authors":"O. Tabata, S. Konishi, P. Cusin, Y. Ito, F. Kawai, S. Hirai, S. Kawamura","doi":"10.1109/MEMSYS.2000.838484","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838484","url":null,"abstract":"This paper reports a device with tunable bending stiffness realized by microfabrication technology. Based on the newly proposed principles, two types of devices whose bending stiffness were controlled by electrostatic force and pneumatic force were fabricated. From the analysis and experiments, the feasibility of the proposed principles were confirmed and the performances of the prototyped devices were demonstrated.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"318 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115834340","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838596
Quanfang Chen, G. Carman
A microscale tribology test system has been developed at UCLA to measure friction and wear in MEMS components. Test results indicate that microscale friction may not follow Amontons' law that states the friction force is only related to the normal force with a coefficient of friction. In this study, test data indicate that the friction coefficient is not constant and it's influenced by crystal orientation, apparent contact area, MEMS material, and fabrication process, as well as the normal force applied. Explanation for the discrepancy may be related to adhesion, which is a critical issue at microscale.
{"title":"Microscale tribology (friction) measurement and influence of crystal orientation and fabrication process","authors":"Quanfang Chen, G. Carman","doi":"10.1109/MEMSYS.2000.838596","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838596","url":null,"abstract":"A microscale tribology test system has been developed at UCLA to measure friction and wear in MEMS components. Test results indicate that microscale friction may not follow Amontons' law that states the friction force is only related to the normal force with a coefficient of friction. In this study, test data indicate that the friction coefficient is not constant and it's influenced by crystal orientation, apparent contact area, MEMS material, and fabrication process, as well as the normal force applied. Explanation for the discrepancy may be related to adhesion, which is a critical issue at microscale.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115794524","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838529
J. Ohara, K. Kano, Y. Takeuchi, N. Ohya, Y. Otsuka, S. Akita
This paper describes a new deep reactive ion etching (D-RIE) process which drastically improves the aspect ratio of the etched trench. The conventional D-RIE process obtains the high aspect ratio trench etching with the protection layer, such as a polymeric layer. The etching anisotropy is limited in this process because this protection layer prevents not only lateral etching, but also vertical etching. In contrast, the new process we developed intensively prevents lateral etching with a dual protection layer consists of a polymeric layer and a SiO/sub 2/ layer on the trench sidewall. Therefore the etching anisotropy and the aspect ratio can be improved. Furthermore, this process can only be performed by switching the introducing gas into the etching chamber.
{"title":"A new deep reactive ion etching process by dual sidewall protection layer","authors":"J. Ohara, K. Kano, Y. Takeuchi, N. Ohya, Y. Otsuka, S. Akita","doi":"10.1109/MEMSYS.2000.838529","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838529","url":null,"abstract":"This paper describes a new deep reactive ion etching (D-RIE) process which drastically improves the aspect ratio of the etched trench. The conventional D-RIE process obtains the high aspect ratio trench etching with the protection layer, such as a polymeric layer. The etching anisotropy is limited in this process because this protection layer prevents not only lateral etching, but also vertical etching. In contrast, the new process we developed intensively prevents lateral etching with a dual protection layer consists of a polymeric layer and a SiO/sub 2/ layer on the trench sidewall. Therefore the etching anisotropy and the aspect ratio can be improved. Furthermore, this process can only be performed by switching the introducing gas into the etching chamber.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114686177","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838571
H. Song, Y. Oh, I. Song, S. Kang, S. Choi, H. Kim, B. Ha, S. Baek, C. Song
A highly reliable, wafer level vacuum packaged and de-coupled vertical microgyroscope was developed. The de-coupled gyroscope which had four driving springs and two sensing springs was designed and fabricated. A new fabrication process which could realize a high aspect ratio and use a thick single crystalline silicon as a structure layer, was proposed. The vacuum environment for operating a vibratory gyroscope was accomplished with vacuum packaging at wafer level. The vacuum level of ambient pressure was about 150 mtorr. The resolution of the gyroscope was 0.013/spl deg//sec/Hz/sup 1/2/. The output nonlinearity was below 2% in /spl plusmn/100/spl deg//s full scale.
{"title":"Wafer level vacuum packaged de-coupled vertical gyroscope by a new fabrication process","authors":"H. Song, Y. Oh, I. Song, S. Kang, S. Choi, H. Kim, B. Ha, S. Baek, C. Song","doi":"10.1109/MEMSYS.2000.838571","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838571","url":null,"abstract":"A highly reliable, wafer level vacuum packaged and de-coupled vertical microgyroscope was developed. The de-coupled gyroscope which had four driving springs and two sensing springs was designed and fabricated. A new fabrication process which could realize a high aspect ratio and use a thick single crystalline silicon as a structure layer, was proposed. The vacuum environment for operating a vibratory gyroscope was accomplished with vacuum packaging at wafer level. The vacuum level of ambient pressure was about 150 mtorr. The resolution of the gyroscope was 0.013/spl deg//sec/Hz/sup 1/2/. The output nonlinearity was below 2% in /spl plusmn/100/spl deg//s full scale.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126681964","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838554
K. Takahashi, K. Nagayama, T. Asano
A novel microfluidic actuator of heater-bubble system is proposed, where a nucleated microbubble rolls right and left repeatedly without any periodic external signal, which means that such bubble motion is applicable as an oscillator. This actuation principle is based on the Marangoni effect and boiling heat transfer, which work as the attraction and release mechanisms respectively. Experimental results show that the frequency of this automatic oscillation is dependent on both bubble size and heater geometry. The surrounding liquid temperature is also a key factor for the feasibility of such motion. The major microfluidic phenomena realizing this actuator are analyzed and discussed qualitatively.
{"title":"Microfluidic oscillator using vapor bubble on thin film heater","authors":"K. Takahashi, K. Nagayama, T. Asano","doi":"10.1109/MEMSYS.2000.838554","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838554","url":null,"abstract":"A novel microfluidic actuator of heater-bubble system is proposed, where a nucleated microbubble rolls right and left repeatedly without any periodic external signal, which means that such bubble motion is applicable as an oscillator. This actuation principle is based on the Marangoni effect and boiling heat transfer, which work as the attraction and release mechanisms respectively. Experimental results show that the frequency of this automatic oscillation is dependent on both bubble size and heater geometry. The surrounding liquid temperature is also a key factor for the feasibility of such motion. The major microfluidic phenomena realizing this actuator are analyzed and discussed qualitatively.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125068484","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838489
L. Dellmann, G. Racine, N. D. de Rooij
This paper will focus on the fabrication and characterization of two types of piezoelectric motors based on the elastic force motor principle. The initial motivation for this work was the development of a motor for wristwatch applications, combining high torque (1 /spl mu/m) with low power consumption (10 /spl mu/W) and small dimensions. Previously reported motors were based on a hybrid assembly of a copper-beryllium rotor, obtained by laser cutting, and a stator consisting of a circular membrane, clamped along its border. The membrane was anisotropically etched in silicon and covered with either ZnO or PZT. We report on an improved and further miniaturized version with fully microfabricated rotors and a new stator design.
{"title":"Micromachined piezoelectric elastic force motor (EFM)","authors":"L. Dellmann, G. Racine, N. D. de Rooij","doi":"10.1109/MEMSYS.2000.838489","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838489","url":null,"abstract":"This paper will focus on the fabrication and characterization of two types of piezoelectric motors based on the elastic force motor principle. The initial motivation for this work was the development of a motor for wristwatch applications, combining high torque (1 /spl mu/m) with low power consumption (10 /spl mu/W) and small dimensions. Previously reported motors were based on a hybrid assembly of a copper-beryllium rotor, obtained by laser cutting, and a stator consisting of a circular membrane, clamped along its border. The membrane was anisotropically etched in silicon and covered with either ZnO or PZT. We report on an improved and further miniaturized version with fully microfabricated rotors and a new stator design.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"187 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116487296","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 : 2000-01-23DOI: 10.1109/MEMSYS.2000.838558
C.S.B. Lee, R. Webb, J. M. Chong, N. MacDonald
10/spl times/10 and 5/spl times/5, a high mirror fill factor (>70%), low voltage operation (<30 V), single crystal silicon (SCS) micromirror arrays have been designed, fabricated, and tested. Each mirror is 320 /spl mu/m by 170 /spl mu/m and is individually addressable. In comparison to thin film micro-mirror arrays, the SCS mirror surface is optically flat and smooth, free of residual stress, and highly reflective after the deposition of a thin aluminum layer. In addition to a flat mirror, high-aspect-ratio grating structures have been fabricated on the surface of the mirrors, enhancing the optical manipulation potential of devices.
{"title":"Single crystal silicon (SCS) micromirror arrays using deep silicon etching and IR alignment","authors":"C.S.B. Lee, R. Webb, J. M. Chong, N. MacDonald","doi":"10.1109/MEMSYS.2000.838558","DOIUrl":"https://doi.org/10.1109/MEMSYS.2000.838558","url":null,"abstract":"10/spl times/10 and 5/spl times/5, a high mirror fill factor (>70%), low voltage operation (<30 V), single crystal silicon (SCS) micromirror arrays have been designed, fabricated, and tested. Each mirror is 320 /spl mu/m by 170 /spl mu/m and is individually addressable. In comparison to thin film micro-mirror arrays, the SCS mirror surface is optically flat and smooth, free of residual stress, and highly reflective after the deposition of a thin aluminum layer. In addition to a flat mirror, high-aspect-ratio grating structures have been fabricated on the surface of the mirrors, enhancing the optical manipulation potential of devices.","PeriodicalId":251857,"journal":{"name":"Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134233129","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：