To satisfy the need of high speed NC (numerical control) machining, an acceleration and deceleration (acc/dec) control model is proposed, and the speed curve is also constructed by the cubic polynomial. The proposed c...To satisfy the need of high speed NC (numerical control) machining, an acceleration and deceleration (acc/dec) control model is proposed, and the speed curve is also constructed by the cubic polynomial. The proposed control model provides continuity of acceleration, which avoids the intense vibration in high speed NC machining. Based on the discrete characteristic of the data sampling interpolation, the acc/dec control discrete mathematical model is also set up and the discrete expression of the theoretical deceleration length is obtained furthermore. Aiming at the question of hardly predetermining the deceleration point in acc/dec control before interpolation, the adaptive acc/dec control algorithm is deduced from the expressions of the theoretical deceleration length. The experimental result proves that the acc/dec control model has the characteristic of easy implementation, stable movement and low impact. The model has been applied in multi-axes high speed micro fabrication machining successfully.展开更多
This study introduces a MEMS accelerometer equipped with an adaptive tuning system for an electrostatic anti-spring.As the input acceleration increases,the sensitivity of the adaptive MEMS accelerometer decreases to c...This study introduces a MEMS accelerometer equipped with an adaptive tuning system for an electrostatic anti-spring.As the input acceleration increases,the sensitivity of the adaptive MEMS accelerometer decreases to compensate for the measurement range.It leverages the benefits of both conventional open-and closed-loop accelerometer designs.Comprehensive theoretical analyses and experimental tests are conducted,showing consistency between theory and experimental results.In comparison to conventional MEMS accelerometer designs,this novel MEMS accelerometer demonstrates enhanced performance.With an actuation voltage of 15.4 V and under 0 g acceleration input,the sensitivity of the accelerometer improves from 1.28 V/g to 39.43 V/g,and the spring constant is reduced from 41.0 N/m to 1.38 N/m.The noise floor also decreases from 8628 ng/√Hz(at 100 Hz)to 279 ng/√Hz(at 100 Hz).The dynamic range enhances from 127 dB to 157 dB.Besides,a hybrid continuous-time interface is utilized to apply the actuation force on the sensing comb fingers.This approach not only simplifies the circuit design but also minimizes the required die area,power consumption.The combination of these features makes the novel MEMS accelerometer both highly sensitive and large measurement range,as a promising solution for various applications.展开更多
Nitrogen narcosis is a neurological syndrome that manifests when humans or animals encounter hyperbaric nitrogen,resulting in a range of motor,emotional,and cognitive abnormalities.The anterior cingulate cortex(ACC)is...Nitrogen narcosis is a neurological syndrome that manifests when humans or animals encounter hyperbaric nitrogen,resulting in a range of motor,emotional,and cognitive abnormalities.The anterior cingulate cortex(ACC)is known for its significant involvement in regulating motivation,cognition,and action.However,its specific contribution to nitrogen narcosis-induced hyperlocomotion and the underlying mechanisms remain poorly understood.Here we report that exposure to hyperbaric nitrogen notably increased the locomotor activity of mice in a pressure-dependent manner.Concurrently,this exposure induced heightened activation among neurons in both the ACC and dorsal medial striatum(DMS).Notably,chemogenetic inhibition of ACC neurons effectively suppressed hyperlocomotion.Conversely,chemogenetic excitation lowered the hyperbaric pressure threshold required to induce hyperlocomotion.Moreover,both chemogenetic inhibition and genetic ablation of activity-dependent neurons within the ACC reduced the hyperlocomotion.Further investigation revealed that ACC neurons project to the DMS,and chemogenetic inhibition of ACC-DMS projections resulted in a reduction in hyperlocomotion.Finally,nitrogen narcosis led to an increase in local field potentials in the theta frequency band and a decrease in the alpha frequency band in both the ACC and DMS.These results collectively suggest that excitatory neurons within the ACC,along with their projections to the DMS,play a pivotal role in regulating the hyperlocomotion induced by exposure to hyperbaric nitrogen.展开更多
基金the Hi-Tech Research and Development Pro-gram (863) of China (No. 2006AA04Z233)the National NaturalScience Foundation of China (No. 50575205)the Natural ScienceFoundation of Zhejiang Province (Nos. Y104243 and Y105686),China
文摘To satisfy the need of high speed NC (numerical control) machining, an acceleration and deceleration (acc/dec) control model is proposed, and the speed curve is also constructed by the cubic polynomial. The proposed control model provides continuity of acceleration, which avoids the intense vibration in high speed NC machining. Based on the discrete characteristic of the data sampling interpolation, the acc/dec control discrete mathematical model is also set up and the discrete expression of the theoretical deceleration length is obtained furthermore. Aiming at the question of hardly predetermining the deceleration point in acc/dec control before interpolation, the adaptive acc/dec control algorithm is deduced from the expressions of the theoretical deceleration length. The experimental result proves that the acc/dec control model has the characteristic of easy implementation, stable movement and low impact. The model has been applied in multi-axes high speed micro fabrication machining successfully.
基金funded by The Science and Technology Development Fund,Macao SAR(FDCT),004/2023/SKLNational Natural Science Foundation of China(No.42204182)Knowledge Innovation Program of Wuhan-Basic Research(No.2023010201010042).
文摘This study introduces a MEMS accelerometer equipped with an adaptive tuning system for an electrostatic anti-spring.As the input acceleration increases,the sensitivity of the adaptive MEMS accelerometer decreases to compensate for the measurement range.It leverages the benefits of both conventional open-and closed-loop accelerometer designs.Comprehensive theoretical analyses and experimental tests are conducted,showing consistency between theory and experimental results.In comparison to conventional MEMS accelerometer designs,this novel MEMS accelerometer demonstrates enhanced performance.With an actuation voltage of 15.4 V and under 0 g acceleration input,the sensitivity of the accelerometer improves from 1.28 V/g to 39.43 V/g,and the spring constant is reduced from 41.0 N/m to 1.38 N/m.The noise floor also decreases from 8628 ng/√Hz(at 100 Hz)to 279 ng/√Hz(at 100 Hz).The dynamic range enhances from 127 dB to 157 dB.Besides,a hybrid continuous-time interface is utilized to apply the actuation force on the sensing comb fingers.This approach not only simplifies the circuit design but also minimizes the required die area,power consumption.The combination of these features makes the novel MEMS accelerometer both highly sensitive and large measurement range,as a promising solution for various applications.
基金supported by the National Natural Science Foundation of China(32030048,82271256,and 32171000)the Natural Science Fund for Colleges and Universities in Jiangsu Province(22KJD340001)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20211107)the Scientific Research Project of"226 Engineering"of Nantong Municipality(2020-9).
文摘Nitrogen narcosis is a neurological syndrome that manifests when humans or animals encounter hyperbaric nitrogen,resulting in a range of motor,emotional,and cognitive abnormalities.The anterior cingulate cortex(ACC)is known for its significant involvement in regulating motivation,cognition,and action.However,its specific contribution to nitrogen narcosis-induced hyperlocomotion and the underlying mechanisms remain poorly understood.Here we report that exposure to hyperbaric nitrogen notably increased the locomotor activity of mice in a pressure-dependent manner.Concurrently,this exposure induced heightened activation among neurons in both the ACC and dorsal medial striatum(DMS).Notably,chemogenetic inhibition of ACC neurons effectively suppressed hyperlocomotion.Conversely,chemogenetic excitation lowered the hyperbaric pressure threshold required to induce hyperlocomotion.Moreover,both chemogenetic inhibition and genetic ablation of activity-dependent neurons within the ACC reduced the hyperlocomotion.Further investigation revealed that ACC neurons project to the DMS,and chemogenetic inhibition of ACC-DMS projections resulted in a reduction in hyperlocomotion.Finally,nitrogen narcosis led to an increase in local field potentials in the theta frequency band and a decrease in the alpha frequency band in both the ACC and DMS.These results collectively suggest that excitatory neurons within the ACC,along with their projections to the DMS,play a pivotal role in regulating the hyperlocomotion induced by exposure to hyperbaric nitrogen.
