The screw-type ultrasonic motor was successfully used in fields of optical focusing system, medical instruments, and so on. In this paper, a cylindrical screw-type ultrasonic motor driven by six transducers is proposed. The motor mainly contains six fixed parts, twelve piezoelectric plates, six transducers, an elastomer and a screw shaft. The piezoelectric plates are bonded to the opposite outside surfaces of transducers and the d31 working mode is adopted. A traveling wave processing along circumferential direction of the elastomer is composited to drive screw shaft and the rotary-linear output motion is achieved without additional conversion mechanism. The motor is designed and its exciting mode is clarified in detail. The vibration performance of the motor is analyzed using Finite Element Method (FEM). The prototype is fabricated and tested. The testing results indicate that the vibration performance of the motor is in good agreement with the simulation results.
{"title":"Design and analysis of a cylindrical screw-type ultrasonic motor driven by six transducers","authors":"Ting-hai Cheng, Liang Wang, Mengfei Yin, Zhaoyang Song, Dong Zhu","doi":"10.1109/SPAWDA.2015.7364513","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364513","url":null,"abstract":"The screw-type ultrasonic motor was successfully used in fields of optical focusing system, medical instruments, and so on. In this paper, a cylindrical screw-type ultrasonic motor driven by six transducers is proposed. The motor mainly contains six fixed parts, twelve piezoelectric plates, six transducers, an elastomer and a screw shaft. The piezoelectric plates are bonded to the opposite outside surfaces of transducers and the d31 working mode is adopted. A traveling wave processing along circumferential direction of the elastomer is composited to drive screw shaft and the rotary-linear output motion is achieved without additional conversion mechanism. The motor is designed and its exciting mode is clarified in detail. The vibration performance of the motor is analyzed using Finite Element Method (FEM). The prototype is fabricated and tested. The testing results indicate that the vibration performance of the motor is in good agreement with the simulation results.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114071833","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364488
Fan Lu, Xiujuan Lin, Bo Geng, Yang Li, Shi-feng Huang
Piezoelectric fiber composites (PFCs) were fabricated by cutting-filling methods to be used as acoustic emission (AE) sensors. The AE sources were simulated by pencil lead broken, the AE signals were collected in the test plate and the linear localization of sound source was measured based on acoustic emission technology. The results showed that the obtained AE signal amplitudes and voltages of PFCs exhibited dependence on the measuring distances and angles. The AE signal amplitudes were different in the orthogonal direction which indicated that the PFCs exhibited well orthotropic property. The attenuation curves showed that the trend of signal attenuation gradually slowed down as the distance increased. The lead broken signals were acquired by the sensors for each time and the accuracy of linear positioning was above a percentage of 95, which indicated that the PFCs possessed good sensitivity and good signal responses to achieve the purpose of positioning and had high accuracy in the process of linear localization.
{"title":"Acoustic emission signal response of piezoelectric fiber composites","authors":"Fan Lu, Xiujuan Lin, Bo Geng, Yang Li, Shi-feng Huang","doi":"10.1109/SPAWDA.2015.7364488","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364488","url":null,"abstract":"Piezoelectric fiber composites (PFCs) were fabricated by cutting-filling methods to be used as acoustic emission (AE) sensors. The AE sources were simulated by pencil lead broken, the AE signals were collected in the test plate and the linear localization of sound source was measured based on acoustic emission technology. The results showed that the obtained AE signal amplitudes and voltages of PFCs exhibited dependence on the measuring distances and angles. The AE signal amplitudes were different in the orthogonal direction which indicated that the PFCs exhibited well orthotropic property. The attenuation curves showed that the trend of signal attenuation gradually slowed down as the distance increased. The lead broken signals were acquired by the sensors for each time and the accuracy of linear positioning was above a percentage of 95, which indicated that the PFCs possessed good sensitivity and good signal responses to achieve the purpose of positioning and had high accuracy in the process of linear localization.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130389378","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364543
Zia Irfan Ahmad, Kun Wang, M. Liu
High ac voltage measurement with known methods requires source loading and problem of potential high current flowing through the measuring circuit or device. This paper describes a novel method to measure medium to high ac signal, its voltage and frequency. The sensor developed is capable to measure high ac voltage signals continuously independent of the temperature effect. It is capable to measure voltage and frequency without loading the source i.e. the source input voltage applied need not be sinked through any resistance or other circuit for its operation. Hence it is a single ended measurement technique and high voltage signal can be measured by probing any potential voltage point.
{"title":"High voltage and frequency sensing based on PZT ceramic linear coupling","authors":"Zia Irfan Ahmad, Kun Wang, M. Liu","doi":"10.1109/SPAWDA.2015.7364543","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364543","url":null,"abstract":"High ac voltage measurement with known methods requires source loading and problem of potential high current flowing through the measuring circuit or device. This paper describes a novel method to measure medium to high ac signal, its voltage and frequency. The sensor developed is capable to measure high ac voltage signals continuously independent of the temperature effect. It is capable to measure voltage and frequency without loading the source i.e. the source input voltage applied need not be sinked through any resistance or other circuit for its operation. Hence it is a single ended measurement technique and high voltage signal can be measured by probing any potential voltage point.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132568321","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364539
Jun-nan Jia, M. Zhao, C. Fan, GuangTao Xu
The measurement of mechanical and electrical properties has become an important topic in studying low-dimensional piezoelectric materials. In this paper, the analytical solution of a piezoelectric beam is derived based on the Bernoulli hypothesis and the three-dimensional constitutive equations. The bending behaviors of the piezoelectric cantilever beam with and without electrodes are studied. It is found that the form of the governing equations and final solutions for the piezoelectric beam is similar to the one for an elastic beam by defining the equivalent bending stiffness.
{"title":"A new discovery of bending behaviors of low-dimensional piezoelectric materials","authors":"Jun-nan Jia, M. Zhao, C. Fan, GuangTao Xu","doi":"10.1109/SPAWDA.2015.7364539","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364539","url":null,"abstract":"The measurement of mechanical and electrical properties has become an important topic in studying low-dimensional piezoelectric materials. In this paper, the analytical solution of a piezoelectric beam is derived based on the Bernoulli hypothesis and the three-dimensional constitutive equations. The bending behaviors of the piezoelectric cantilever beam with and without electrodes are studied. It is found that the form of the governing equations and final solutions for the piezoelectric beam is similar to the one for an elastic beam by defining the equivalent bending stiffness.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128861012","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364472
Long-fei Li, Yong-qiang Guo
A hybrid method, which combines the method of reverberation-ray matrix (MRRM) and the transfer matrix method (TMM), is presented for the analysis of longitudinal-wave bands in periodic piezoelectric rods. The unit cell of the periodic rods is made of alternate piezoelectric and elastic rods modeled by the Love Rod Theory. The transversal effect of the piezoelectric rods is exploited. The MRRM is introduced to derive the member transfer matrix of the constituent rods. The global transfer matrix of the unit cell is obtained by further considering the continuous conditions between the adjacent rods. Due to the Floquet-Bloch principle, the propagation constants are found to be the natural logarithm of the eigenvalues of the global transfer matrix. The frequency spectra representing the longitudinal-wave bands can then be drawn. Numerical examples are given to validate the proposed hybrid method and to illustrate the influences of high frequency, the Poisson's effect of the constituent rods, the thickness of the electrodes and the applied electric capacity and voltage on the frequency bands. These effects can be used to passively or actively tune the longitudinal-wave bands in periodic piezoelectric composite structures.
{"title":"Analyzing and tuning longitudinal-wave bands in periodic piezoelectric rods","authors":"Long-fei Li, Yong-qiang Guo","doi":"10.1109/SPAWDA.2015.7364472","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364472","url":null,"abstract":"A hybrid method, which combines the method of reverberation-ray matrix (MRRM) and the transfer matrix method (TMM), is presented for the analysis of longitudinal-wave bands in periodic piezoelectric rods. The unit cell of the periodic rods is made of alternate piezoelectric and elastic rods modeled by the Love Rod Theory. The transversal effect of the piezoelectric rods is exploited. The MRRM is introduced to derive the member transfer matrix of the constituent rods. The global transfer matrix of the unit cell is obtained by further considering the continuous conditions between the adjacent rods. Due to the Floquet-Bloch principle, the propagation constants are found to be the natural logarithm of the eigenvalues of the global transfer matrix. The frequency spectra representing the longitudinal-wave bands can then be drawn. Numerical examples are given to validate the proposed hybrid method and to illustrate the influences of high frequency, the Poisson's effect of the constituent rods, the thickness of the electrodes and the applied electric capacity and voltage on the frequency bands. These effects can be used to passively or actively tune the longitudinal-wave bands in periodic piezoelectric composite structures.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123528729","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364449
Lu Han, Weiqing Huang, Yin Wang
This study presents a new type of linear motor based on the micro-vibration of piezoelectric stacks. The working mechanism of the motor was analyzed. Then the clamping structure and overall structure of motor was designed. Further, the best size of the flexible structures was obtained by means of finite element analysis method on the clamping structure. The prototype was manufactured and tested. Then the speed characteristic curve of motor is analyzed. The experimental results on the prototype verify the feasibility of the scheme, by applying voltage signal of peak to peak value 100V and frequency of 150 Hz, the no-load speed is 1.23 mm/s and the thrust is 1.6 N, and it meets the basic requirement of the precision of linear feed system.
{"title":"Clamp stepper piezoelectric linear motor with composite of two amplifications","authors":"Lu Han, Weiqing Huang, Yin Wang","doi":"10.1109/SPAWDA.2015.7364449","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364449","url":null,"abstract":"This study presents a new type of linear motor based on the micro-vibration of piezoelectric stacks. The working mechanism of the motor was analyzed. Then the clamping structure and overall structure of motor was designed. Further, the best size of the flexible structures was obtained by means of finite element analysis method on the clamping structure. The prototype was manufactured and tested. Then the speed characteristic curve of motor is analyzed. The experimental results on the prototype verify the feasibility of the scheme, by applying voltage signal of peak to peak value 100V and frequency of 150 Hz, the no-load speed is 1.23 mm/s and the thrust is 1.6 N, and it meets the basic requirement of the precision of linear feed system.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117210152","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364481
Ding-wen Wang, Yingxiang Liu, Weishan Chen, Jun-kao Liu
A new bending-hybrid-modes piezoelectric actuator was designed, and analyzed. The two operating principles using the whole piece of PZT ceramic plates were discussed, and compared with the traditional operating principle using the half piece of PZT ceramics. The effects of the no polarization part on the bending resonance frequencies were studied by modal analysis. Then, harmonic analysis was developed to obtain the electromechanical coupling factor. The effect of the size of no polarization part on the electromechanical coupling factor was obtained. As last, the vibration trajectories of the two tip ends were investigated by transient analysis. The two tip ends generated elliptical movements when the two bending vibrations were superimposed. The study gives detail discussion about the exciting methods for bending vibration of a bolt-clamped transducer. The analysis results can guide the design of the piezoelectric actuator using bending hybrid modes.
{"title":"Study on the exciting method for piezoelectric actuator using bending hybrid modes","authors":"Ding-wen Wang, Yingxiang Liu, Weishan Chen, Jun-kao Liu","doi":"10.1109/SPAWDA.2015.7364481","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364481","url":null,"abstract":"A new bending-hybrid-modes piezoelectric actuator was designed, and analyzed. The two operating principles using the whole piece of PZT ceramic plates were discussed, and compared with the traditional operating principle using the half piece of PZT ceramics. The effects of the no polarization part on the bending resonance frequencies were studied by modal analysis. Then, harmonic analysis was developed to obtain the electromechanical coupling factor. The effect of the size of no polarization part on the electromechanical coupling factor was obtained. As last, the vibration trajectories of the two tip ends were investigated by transient analysis. The two tip ends generated elliptical movements when the two bending vibrations were superimposed. The study gives detail discussion about the exciting methods for bending vibration of a bolt-clamped transducer. The analysis results can guide the design of the piezoelectric actuator using bending hybrid modes.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125180240","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364484
Yao Wang, Zai-lin Yang, Jian-wei Zhang, Fa-qiang Qiu, Xu-sheng Luo
The reflection and refraction of SH plane wave at the interface between two inhomogeneous half-spaces are studied in this paper, where the distributions of shear modulus and mass density all obey the parabolic functions. Based on the fundamental solution of the wave equation, the general formulations of incident wave, reflected wave and transmitted wave are given. Substituting the formulations into the boundary condition at the interface, the unknown coefficients are obtained, where the absolute values of these coefficients represent the amplitudes of reflected wave and transmitted wave. A series of parametric discussion are made to exhibit the effect on the reflection and refraction by wave number, incident angle and material properties.
{"title":"Reflection and refraction of SH plane waves at the interface between two inhomogeneous half-spaces","authors":"Yao Wang, Zai-lin Yang, Jian-wei Zhang, Fa-qiang Qiu, Xu-sheng Luo","doi":"10.1109/SPAWDA.2015.7364484","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364484","url":null,"abstract":"The reflection and refraction of SH plane wave at the interface between two inhomogeneous half-spaces are studied in this paper, where the distributions of shear modulus and mass density all obey the parabolic functions. Based on the fundamental solution of the wave equation, the general formulations of incident wave, reflected wave and transmitted wave are given. Substituting the formulations into the boundary condition at the interface, the unknown coefficients are obtained, where the absolute values of these coefficients represent the amplitudes of reflected wave and transmitted wave. A series of parametric discussion are made to exhibit the effect on the reflection and refraction by wave number, incident angle and material properties.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133760815","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364528
Ben-jie Ding, Jianke Du, J. Lou, Ji Wang, T. Ma, Bin Huang, Li-wen He
It has been discovered that laminate composites of longitudinally magnetized magnetostrictive and transversely poled piezoelectric layers have a giant magneto-electric effect under a low bias magnetic field. The maximum induced magnetoelectric coupling coefficient at resonance is 3.66 V/(cm×Oe), which is over 11 times higher than magnetoelectric coupling coefficient at sub-resonance frequency. The results reveal that laminated of PMN-PT and Terfenol-D have a high sensitivity of less than 10-6T to a DC magnetic field.
{"title":"Vibration of magnetoelectric laminate composite PMN-PT under bias magnetic fields","authors":"Ben-jie Ding, Jianke Du, J. Lou, Ji Wang, T. Ma, Bin Huang, Li-wen He","doi":"10.1109/SPAWDA.2015.7364528","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364528","url":null,"abstract":"It has been discovered that laminate composites of longitudinally magnetized magnetostrictive and transversely poled piezoelectric layers have a giant magneto-electric effect under a low bias magnetic field. The maximum induced magnetoelectric coupling coefficient at resonance is 3.66 V/(cm×Oe), which is over 11 times higher than magnetoelectric coupling coefficient at sub-resonance frequency. The results reveal that laminated of PMN-PT and Terfenol-D have a high sensitivity of less than 10-6T to a DC magnetic field.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126511098","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364491
Di Wu, Liangliang Zhang, Wenshuai Xu, Yang Gao
By using the general solutions of one-dimensional quasicrystals with piezoelectric effect and introducing four potential functions, the plane problem of orthorhombic piezoelectric QCs subjected to the point forces and point charge is taken into account. The fundamental solutions in a closed form are obtained and the numerical results are given. The mechanical behaviors of 1D piezoelectric QC with different material constants are studied. Moreover, some valuable conclusions are obtained.
{"title":"Fundamental solutions of plane problem of one-dimensional quasicrystal with piezoelectric effect","authors":"Di Wu, Liangliang Zhang, Wenshuai Xu, Yang Gao","doi":"10.1109/SPAWDA.2015.7364491","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364491","url":null,"abstract":"By using the general solutions of one-dimensional quasicrystals with piezoelectric effect and introducing four potential functions, the plane problem of orthorhombic piezoelectric QCs subjected to the point forces and point charge is taken into account. The fundamental solutions in a closed form are obtained and the numerical results are given. The mechanical behaviors of 1D piezoelectric QC with different material constants are studied. Moreover, some valuable conclusions are obtained.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125368004","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：