The spin-exchange relaxation-free atomic gyroscope,with its exceptionally high theoretical precision,demonstrates immense potential to become the next-generation strategic-grade gyroscope.However,due to technological ...The spin-exchange relaxation-free atomic gyroscope,with its exceptionally high theoretical precision,demonstrates immense potential to become the next-generation strategic-grade gyroscope.However,due to technological noise,there is still a significant gap between its actual precision and theoretical precision.This study identifies the key factor limiting the precision of the SERF gyroscope as coupling noise.By optimizing the detection loop structure,a distinction between the dual-axis signals'response to optical and magnetic fields was achieved-where the optical errors responded similarly,while the response to magnetic noise was opposite.Based on the differences in the optical-magnetic response of the dual-axis signals,empirical mode decomposition was used to decompose the dual-axis gyroscope signals into multiple intrinsic mode functions,and Allan deviation analysis was applied to analyze the noise characteristics of the intrinsic mode functions over various periods.This study successfully reveals that optical errors caused by thermal-optical coupling and long-period magnetic noise induced by thermal-magnetic coupling are the dominant factors limiting the long-term stability of the SERF gyroscope.Based on these analyses,the study concludes that to achieve strategic-grade precision for the SERF gyroscope,it is essential to effectively address the noise issues caused by multi-physical field couplings.展开更多
This study focuses on the distribution of high-resistance media(pores and spinels)within ZnO varistors and explores the mechanical and electrical failure mechanisms of varistors under different pulse actions.Micro-CT ...This study focuses on the distribution of high-resistance media(pores and spinels)within ZnO varistors and explores the mechanical and electrical failure mechanisms of varistors under different pulse actions.Micro-CT technology revealed that the proportion of high-resistance media in the edge area is much higher than in the internal area.Simulation results indicated that a high porosity significantly increased temperature rise and thermal stress concentration,while a high spinel proportion exacerbated current concentration but had a relatively minor impact on the distribution of temperature rise and thermal stress.Under an electric field of 1000-1250 V/mm,pores transition from an insulating state to a conductive state,especially in the edge area,leading to concentrated temperature rise and thermal stress.Once the thermal stress exceeded the critical value of the mechanical strength of the pores,cracking failure occurred.The high spinel proportion in the edge area further intensified current concentration under high electric fields,working together with the conductivity of the pores to produce a significant local temperature rise,melting grain structure,and ultimately leading to puncture failure.This study provides a new perspective for understanding the failure mechanism of ZnO varistors and lays a theoretical foundation for the development of varistor materials with high energy absorption capacity.展开更多
<div style="text-align:justify;"> Rainfall infiltration is a porous medium flow problem with variable saturation. Based on the theoretical analysis of the flow field, electrical conductivity of rocks, ...<div style="text-align:justify;"> Rainfall infiltration is a porous medium flow problem with variable saturation. Based on the theoretical analysis of the flow field, electrical conductivity of rocks, the electrical field, the paper simulates the coupling relationship between the water saturation in soil and the apparent resistivity distribution. It combines the Richards equation, the Archie formula and the Laplace equation. The experiment simulates the potential field data by the Wenner setting in electrical exploration on a two-layer geologic model with continuous rainfall during 5 days, which shows that the effective saturation in soil is increasing with the rainfall time, while the apparent resistivity is decreasing. This can provide a theoretical basis for the analyzing the rainfall infiltration and porosity of the soil by using high-density electrical method in the future. </div>展开更多
基金supported by Hefei National Laboratory,Innovation Program for Quantum Science and Technology(2021ZD0300400/2021ZD0300402)the Beijing Natural Science Foundation(3252013)the China Postdoctoral Science Foundation(2024T171116).
文摘The spin-exchange relaxation-free atomic gyroscope,with its exceptionally high theoretical precision,demonstrates immense potential to become the next-generation strategic-grade gyroscope.However,due to technological noise,there is still a significant gap between its actual precision and theoretical precision.This study identifies the key factor limiting the precision of the SERF gyroscope as coupling noise.By optimizing the detection loop structure,a distinction between the dual-axis signals'response to optical and magnetic fields was achieved-where the optical errors responded similarly,while the response to magnetic noise was opposite.Based on the differences in the optical-magnetic response of the dual-axis signals,empirical mode decomposition was used to decompose the dual-axis gyroscope signals into multiple intrinsic mode functions,and Allan deviation analysis was applied to analyze the noise characteristics of the intrinsic mode functions over various periods.This study successfully reveals that optical errors caused by thermal-optical coupling and long-period magnetic noise induced by thermal-magnetic coupling are the dominant factors limiting the long-term stability of the SERF gyroscope.Based on these analyses,the study concludes that to achieve strategic-grade precision for the SERF gyroscope,it is essential to effectively address the noise issues caused by multi-physical field couplings.
基金National Natural Science Foundation of China(Youth Fund Program),Grant/Award Number:52107158Natural Science Foundation of Sichuan Province,Grant/Award Number:2024NSFSC0116Project of‘Gathering Resources to Prosper Sichuan’,Grant/Award Number:25JYXC0046。
文摘This study focuses on the distribution of high-resistance media(pores and spinels)within ZnO varistors and explores the mechanical and electrical failure mechanisms of varistors under different pulse actions.Micro-CT technology revealed that the proportion of high-resistance media in the edge area is much higher than in the internal area.Simulation results indicated that a high porosity significantly increased temperature rise and thermal stress concentration,while a high spinel proportion exacerbated current concentration but had a relatively minor impact on the distribution of temperature rise and thermal stress.Under an electric field of 1000-1250 V/mm,pores transition from an insulating state to a conductive state,especially in the edge area,leading to concentrated temperature rise and thermal stress.Once the thermal stress exceeded the critical value of the mechanical strength of the pores,cracking failure occurred.The high spinel proportion in the edge area further intensified current concentration under high electric fields,working together with the conductivity of the pores to produce a significant local temperature rise,melting grain structure,and ultimately leading to puncture failure.This study provides a new perspective for understanding the failure mechanism of ZnO varistors and lays a theoretical foundation for the development of varistor materials with high energy absorption capacity.
文摘<div style="text-align:justify;"> Rainfall infiltration is a porous medium flow problem with variable saturation. Based on the theoretical analysis of the flow field, electrical conductivity of rocks, the electrical field, the paper simulates the coupling relationship between the water saturation in soil and the apparent resistivity distribution. It combines the Richards equation, the Archie formula and the Laplace equation. The experiment simulates the potential field data by the Wenner setting in electrical exploration on a two-layer geologic model with continuous rainfall during 5 days, which shows that the effective saturation in soil is increasing with the rainfall time, while the apparent resistivity is decreasing. This can provide a theoretical basis for the analyzing the rainfall infiltration and porosity of the soil by using high-density electrical method in the future. </div>
