2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)最新文献
Pub Date : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234914
H. Kishi, T. Tsurumi, Takayuki Gotoh, K. Morita, Y. Iwazaki
We investigated the effect of AC and Uni-Polar polarization on piezoelectric properties of multilayer ceramics using three types of Ferroelectric materials, such as BT, LNKN and PZT based systems. We found LNKN and PZT systems showed both AC and Uni-Poling effect that showed high d31* value comparable to DC polarization. Especially, PZT systems showed AC and Uni-Polling effect in the wide frequency range, even at a high frequency of 20 kHz, which indicates that it can be polarized in an extremely short time of 0.1 ms. The mechanisms of polarization in these materials will be discussed.
{"title":"Study on Polarization Behavior of Multilayer Ceramics Using Various Ferroelectric Materials","authors":"H. Kishi, T. Tsurumi, Takayuki Gotoh, K. Morita, Y. Iwazaki","doi":"10.1109/IFCS-ISAF41089.2020.9234914","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234914","url":null,"abstract":"We investigated the effect of AC and Uni-Polar polarization on piezoelectric properties of multilayer ceramics using three types of Ferroelectric materials, such as BT, LNKN and PZT based systems. We found LNKN and PZT systems showed both AC and Uni-Poling effect that showed high d31* value comparable to DC polarization. Especially, PZT systems showed AC and Uni-Polling effect in the wide frequency range, even at a high frequency of 20 kHz, which indicates that it can be polarized in an extremely short time of 0.1 ms. The mechanisms of polarization in these materials will be discussed.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"61 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88800222","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234903
A. Pluteshko
The paper presents a method of low phase noise frequency division using PLL technique. The condition that provides for the residual phase noise comparable to the regenerative frequency divider (RFDiv) performance is given. The advantages over the RFDiv are shown. Some of these include the easier achievable frequency division ratios larger than 2 and the optimal performance not requiring the circuit adjustment. The measured data on the residual phase noise of the PLL frequency divider by 10 are presented. These show that the measurement setup noise floor of −139 dB(rad2/Hz) at 10 Hz offset is virtually unaffected by the noise of the divider.
{"title":"Low Phase Noise Frequency Division Using PLL","authors":"A. Pluteshko","doi":"10.1109/IFCS-ISAF41089.2020.9234903","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234903","url":null,"abstract":"The paper presents a method of low phase noise frequency division using PLL technique. The condition that provides for the residual phase noise comparable to the regenerative frequency divider (RFDiv) performance is given. The advantages over the RFDiv are shown. Some of these include the easier achievable frequency division ratios larger than 2 and the optimal performance not requiring the circuit adjustment. The measured data on the residual phase noise of the PLL frequency divider by 10 are presented. These show that the measurement setup noise floor of −139 dB(rad2/Hz) at 10 Hz offset is virtually unaffected by the noise of the divider.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"80 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83523755","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234863
Wen-Hung Tseng, Shinn-Yan Lin
In this paper, we introduce a cost-effective calibration procedure of moving a portable cesium clock to meet the requirements of remote time-scale calibration in Taiwan. By setting some reasonable limits, e.g., a limit of 30 hours allowed for the elapsed round-trip time, the expanded time uncertainty with a coverage factor of $mathrm{k}=2$ is estimated as 7.36 ns for the calibration. The procedure also allows us to complete a calibration trip between TL and one of the most laboratories in the western part of Taiwan with a car.
{"title":"Remote Calibration of Time Scale Difference by Moving a Portable Cesium Clock","authors":"Wen-Hung Tseng, Shinn-Yan Lin","doi":"10.1109/IFCS-ISAF41089.2020.9234863","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234863","url":null,"abstract":"In this paper, we introduce a cost-effective calibration procedure of moving a portable cesium clock to meet the requirements of remote time-scale calibration in Taiwan. By setting some reasonable limits, e.g., a limit of 30 hours allowed for the elapsed round-trip time, the expanded time uncertainty with a coverage factor of $mathrm{k}=2$ is estimated as 7.36 ns for the calibration. The procedure also allows us to complete a calibration trip between TL and one of the most laboratories in the western part of Taiwan with a car.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"21 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86288317","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234898
Ryoma Miyake, M. Kiuchi, S. Yoshida, Shuji Tanaka, G. Fox
A commercially produced monocrystalline-like epitaxial PZT film is described for piezoelectric MEMS applications. Films with a thickness of $1 mu mathrm{m}$ to $2 mu mathrm{m}$ exhibit a typical transverse piezoelectric d31 coefficient of −185 pm/V, relative dielectric permittivity of 430 and dielectric loss of 0.015. These films are commercially available for piezoelectric MEMS device development and production.
描述了一种用于压电MEMS应用的商业生产的单晶样外延PZT薄膜。厚度为$1 mu mathm {m}$至$2 mu mathm {m}$的薄膜，典型的横向压电d31系数为- 185 pm/V，相对介电常数为430，介电损耗为0.015。这些薄膜可用于压电MEMS器件的开发和生产。
{"title":"Commercial Production of Epitaxial PZT for Piezoelectric MEMS Applications","authors":"Ryoma Miyake, M. Kiuchi, S. Yoshida, Shuji Tanaka, G. Fox","doi":"10.1109/IFCS-ISAF41089.2020.9234898","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234898","url":null,"abstract":"A commercially produced monocrystalline-like epitaxial PZT film is described for piezoelectric MEMS applications. Films with a thickness of $1 mu mathrm{m}$ to $2 mu mathrm{m}$ exhibit a typical transverse piezoelectric d31 coefficient of −185 pm/V, relative dielectric permittivity of 430 and dielectric loss of 0.015. These films are commercially available for piezoelectric MEMS device development and production.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"27 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79126491","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234834
Ernest Ting-Ta Yen, Benyong Zhang, D. Griffith, Keegan Martin, M. Chowdhury, J. Segovia-Fernandez, Trevor Tarsi, B. Goodlin, B. Cook, R. Jackson
This paper introduces TI's mirror-encapsulated bulk acoustic wave (BAW) resonator technology and two novel system applications. Similar to other BAW resonators, the dual-Bragg acoustic resonator (DBAR) utilizes piezoelectric aluminum nitride (AIN) thin film between two metal electrodes. However, the DBAR operation requires no cavity on either side of the resonant body. This unique micro-acoustic resonator technology enables cost-effective system integration in mass production. The first system application is a novel network synchronizer based on an integrated ultra-low noise voltage-controlled BAW oscillator (VCBO). When operating as a jitter cleaner, the synthesized output clock rms jitter can be reduced to less than 60 fs (12 kHz–20 MHz). The second application uses this 2.5 GHz DBAR-oscillator as a high-frequency reference clock, achieving a ±30 ppm Bluetooth Low Energy (BLE) compliant crystal-less radio.
{"title":"High-frequency Reference System Implementations Utilizing Mirror-encapsulated BAW Resonators","authors":"Ernest Ting-Ta Yen, Benyong Zhang, D. Griffith, Keegan Martin, M. Chowdhury, J. Segovia-Fernandez, Trevor Tarsi, B. Goodlin, B. Cook, R. Jackson","doi":"10.1109/IFCS-ISAF41089.2020.9234834","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234834","url":null,"abstract":"This paper introduces TI's mirror-encapsulated bulk acoustic wave (BAW) resonator technology and two novel system applications. Similar to other BAW resonators, the dual-Bragg acoustic resonator (DBAR) utilizes piezoelectric aluminum nitride (AIN) thin film between two metal electrodes. However, the DBAR operation requires no cavity on either side of the resonant body. This unique micro-acoustic resonator technology enables cost-effective system integration in mass production. The first system application is a novel network synchronizer based on an integrated ultra-low noise voltage-controlled BAW oscillator (VCBO). When operating as a jitter cleaner, the synthesized output clock rms jitter can be reduced to less than 60 fs (12 kHz–20 MHz). The second application uses this 2.5 GHz DBAR-oscillator as a high-frequency reference clock, achieving a ±30 ppm Bluetooth Low Energy (BLE) compliant crystal-less radio.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"8 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87486341","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234879
D. Lehninger, T. Ali, R. Olivo, M. Lederer, T. Kämpfe, K. Mertens, K. Seidel
The discovery of ferroelectricity in thin films of doped hafnium oxide has led to a renaissance of ferroelectric (FE) memory concepts. Compared to all inspected dopants, zirconium doped hafnium oxide (HZO) crystallizes at the lowest temperatures. Thus, this material system is ideal for the implementation of FE functionalities into the back-end-of-line (BEoL). So far, the FE phase is achieved by rapid thermal annealing (RTA) of prior amorphous HZO films. Recently, it was shown that a sole furnace anneal at 400°C is sufficient to functionalize the films. Herein, a wide range of annealing conditions are compared in order to further reduce the thermal budget and the number of process steps. It is found that furnace-annealing at 300°C for 1 h crystallizes the HZO films in the FE phase. With respect to crystallinity, these films show no significant degradation compared to films annealed at 400°C. Nevertheless, the remanent polarization reduces slightly with temperature, but is still sufficient even at 300°C.
{"title":"Furnace annealed HfO2-Films for the Integration of Ferroelectric Functionalities into the BEoL","authors":"D. Lehninger, T. Ali, R. Olivo, M. Lederer, T. Kämpfe, K. Mertens, K. Seidel","doi":"10.1109/IFCS-ISAF41089.2020.9234879","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234879","url":null,"abstract":"The discovery of ferroelectricity in thin films of doped hafnium oxide has led to a renaissance of ferroelectric (FE) memory concepts. Compared to all inspected dopants, zirconium doped hafnium oxide (HZO) crystallizes at the lowest temperatures. Thus, this material system is ideal for the implementation of FE functionalities into the back-end-of-line (BEoL). So far, the FE phase is achieved by rapid thermal annealing (RTA) of prior amorphous HZO films. Recently, it was shown that a sole furnace anneal at 400°C is sufficient to functionalize the films. Herein, a wide range of annealing conditions are compared in order to further reduce the thermal budget and the number of process steps. It is found that furnace-annealing at 300°C for 1 h crystallizes the HZO films in the FE phase. With respect to crystallinity, these films show no significant degradation compared to films annealed at 400°C. Nevertheless, the remanent polarization reduces slightly with temperature, but is still sufficient even at 300°C.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"52 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90928160","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234816
Hyunwook Park, J. Tallant, Xianli Zhang, J. Noble, D. Guan, N. Dao, K. Overstreet
Ion traps are a rugged, proven technology that supports high-performance and manufacturable time keeping solutions. Our approach to this implementation is based on the 12.6 GHz hyperfine transition of 171Yb+ ions confined in a linear Paul trap. We report an instability of $6times 10^{-13} tau^{-1/2}$ up to averaging time $tau=100 mathrm{s}$ in the presence of buffer gas, which is a 40% improvement from our previous report. The ion trap is implemented in a 2U-compatible enclosure, which is characterized by ion storage times >95 days and Allan deviation down to $4 times 10^{-15}$ at $tau=2times 10^{5} mathrm{s}$.
{"title":"171Yb+ Microwave Clock for Military and Commercial Applications","authors":"Hyunwook Park, J. Tallant, Xianli Zhang, J. Noble, D. Guan, N. Dao, K. Overstreet","doi":"10.1109/IFCS-ISAF41089.2020.9234816","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234816","url":null,"abstract":"Ion traps are a rugged, proven technology that supports high-performance and manufacturable time keeping solutions. Our approach to this implementation is based on the 12.6 GHz hyperfine transition of 171Yb+ ions confined in a linear Paul trap. We report an instability of $6times 10^{-13} tau^{-1/2}$ up to averaging time $tau=100 mathrm{s}$ in the presence of buffer gas, which is a 40% improvement from our previous report. The ion trap is implemented in a 2U-compatible enclosure, which is characterized by ion storage times >95 days and Allan deviation down to $4 times 10^{-15}$ at $tau=2times 10^{5} mathrm{s}$.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"31 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79131255","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234842
H. Pak, Adam Michael Jarrett
This paper reports the development and optimization of a 9x7mm OCXO using an AT strip crystal mounted within an isothermal envelope to minimize the effects of mechanical stress on the crystal blank. This concept can be realized by using Finite Element Method (FEM) as a design aid to achieve low and symmetrical thermal gradients across the quartz blank. As a result, it yields stability suitable for high-volume, low-cost telecommunication applications.
{"title":"Design Optimization for High-Volume, Low-Cost 9x7 OCXO","authors":"H. Pak, Adam Michael Jarrett","doi":"10.1109/IFCS-ISAF41089.2020.9234842","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234842","url":null,"abstract":"This paper reports the development and optimization of a 9x7mm OCXO using an AT strip crystal mounted within an isothermal envelope to minimize the effects of mechanical stress on the crystal blank. This concept can be realized by using Finite Element Method (FEM) as a design aid to achieve low and symmetrical thermal gradients across the quartz blank. As a result, it yields stability suitable for high-volume, low-cost telecommunication applications.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"62 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78699168","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234853
Tiantian Shi, Jianxiang Miao, D. Pan, Jingbiao Chen
The hyperfine structure (hfs) of Cs 7P1/2 state is measured utilizing four-level active optical clock. Combing the Doppler effect and the active stimulated emission, the accuracy of Cs 7P1/2 hfs is expected to be optimized. The correction terms of experimental results, such as cavity-pulling effect, light shift and collision shift, are analyzed. Such a scheme can be widely extended to other alkali-metal atoms to enrich the measurements of hfs.
{"title":"Hyperfine-structure Measurement of the 7P1/2 State in 133Cs Based on the Active Optical Clock","authors":"Tiantian Shi, Jianxiang Miao, D. Pan, Jingbiao Chen","doi":"10.1109/IFCS-ISAF41089.2020.9234853","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234853","url":null,"abstract":"The hyperfine structure (hfs) of Cs 7P1/2 state is measured utilizing four-level active optical clock. Combing the Doppler effect and the active stimulated emission, the accuracy of Cs 7P1/2 hfs is expected to be optimized. The correction terms of experimental results, such as cavity-pulling effect, light shift and collision shift, are analyzed. Such a scheme can be widely extended to other alkali-metal atoms to enrich the measurements of hfs.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"7 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83434532","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 : 2020-07-01DOI: 10.1109/IFCS-ISAF41089.2020.9234878
F. Constantin
Precision measurements of the molecular iodine optical transitions can be exploited for constraining a possible time variation of the fundamental constants. The sensitivities of the molecular frequencies to a variation of the proton-to-electron mass ratio and of the fine structure constant are calculated. Compact molecular iodine clocks, designed for space applications with improved stability performances, enable fractional frequency reproducibility at the 10−15 level. The comparison of the optical iodine clocks based on transitions at 532 nm, 514 nm and 502 nm with the Cs frequency standard can constrain a fractional time variation of the proton-to-electron mass ratio and of the fine structure constant at the 10−14 yr−1 level.
{"title":"Towards Probing a Variation of Fundamental Constants with Optical Clock Transitions of 127I2","authors":"F. Constantin","doi":"10.1109/IFCS-ISAF41089.2020.9234878","DOIUrl":"https://doi.org/10.1109/IFCS-ISAF41089.2020.9234878","url":null,"abstract":"Precision measurements of the molecular iodine optical transitions can be exploited for constraining a possible time variation of the fundamental constants. The sensitivities of the molecular frequencies to a variation of the proton-to-electron mass ratio and of the fine structure constant are calculated. Compact molecular iodine clocks, designed for space applications with improved stability performances, enable fractional frequency reproducibility at the 10−15 level. The comparison of the optical iodine clocks based on transitions at 532 nm, 514 nm and 502 nm with the Cs frequency standard can constrain a fractional time variation of the proton-to-electron mass ratio and of the fine structure constant at the 10−14 yr−1 level.","PeriodicalId":6872,"journal":{"name":"2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF)","volume":"63 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91085356","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：