The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has ...The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has met the engineering requirements on the ground will change, seriously affecting the imaging quality. In order to eliminate the influence of gravity and to ensure the consistency of space and ground, gravity unloading must be performed. In order to meet the requirements of processing and testing for the large aperture space mirror in the state of vertical optical axis, a universal gravity unloading device was proposed. It was an active support and used air cylinders to provide accurate unloading force. First, the design flow of gravity unloading was introduced;then the detailed design of the mechanical structure and control system was given;then the performance parameters of the two types of cylinders were tested and compared, including the force-pressure relationship curve and the force-position relationship curve;finally, the experimental verification of the gravity unloading device was carried out;for a mirror with an aperture of ?2100 mm, the gravity unloading device was designed and a vertical detection optical path was built. The test results showed that by using this gravity unloading device, the actual processing surface accuracy of the mirror was better than 1/50λ-RMS, which met the application requirement of the optical system. Thus, it can be seen that using this gravity unloading device can effectively unload the gravity of the mirror and realize the accurate processing and measurement of the mirror surface. .展开更多
Objective:To evaluate the effects of action observation therapy,which is based on mirror neuron theory,on upper limb function and activities of daily living in patients with stroke.Methods:Sixty-one patients with stro...Objective:To evaluate the effects of action observation therapy,which is based on mirror neuron theory,on upper limb function and activities of daily living in patients with stroke.Methods:Sixty-one patients with stroke were randomly divided into two groups;those in the control group received routine rehabilitation treatment and nursing,whereas those in the experimental group additionally received eight weeks of action observation therapy for 30 min,six times per week.Patients receiving action observation therapy watched videos depicting a model performing specific motor actions typically performed in daily life before enacting the same actions themselves.All patients were assessed using the FugleMeyer assessment,Barthel index and the modified Ashworth scale at baseline and at eight weeks,after treatment.Results:After the eight weeks of treatment,both groups of patients exhibited significant improvement in all the measurements(all p<0.05).Furthermore,the FugleMeyer assessment,Barthel index and modified Ashworth scale scores were significantly higher in the experimental group compared to the control group(all p<0.05).Conclusion:Action observation therapy significantly improves upper extremity motor function and performance of activities of daily living,and alleviates upper limb spasticity in patients with stroke.展开更多
Mirror neuron system can be activated by observation and execution of an action.It has an important function of action understanding.We investigated brain activations in humans by observing the strength of a hand gras...Mirror neuron system can be activated by observation and execution of an action.It has an important function of action understanding.We investigated brain activations in humans by observing the strength of a hand grasp using functional magnetic resonance imaging.Twenty right-handed healthy individuals,consisting of 10 males and 10 females,aged 22.40 ± 2.04 years,were recruited into this study from September to November 2017 via posters.Light hand grasp task video showed a hand lightly grasping and releasing a ball repeatedly.Powerful hand grasp task video showed a hand tightly grasping and releasing a ball repeatedly.Functional magnetic resonance imaging block design paradigm comprised five stimulation blocks alternating with five baseline blocks.Stimulation blocks were presented with two stimulus tasks,consisting of a light grasp and a powerful grasp.Region of interest was defined around the inferior parietal lobule,inferior frontal gyrus,and superior temporal sulcus which have been called mirror neuron system.The inferior parietal lobule,fusiform,postcentral,occipital,temporal,and frontal gyri were activated during light and powerful grasp tasks.The BOLD signal response of a powerful grasp was stronger than that of a light grasp.These results suggest that brain activation of the inferior parietal lobule,which is the core brain region of the mirror neuron system,was stronger in the powerful grasp task than in the light grasp task.We believe that our results might be helpful for instructing rehabilitation of brain injury.This study was approved by the Institutional Review Board of Daegu Oriental Hospital of Daegu Haany University on September 8,2017 (approval No.DHUMC-D-17020-PRO-01).展开更多
We present a spatiotemporal model of pulse amplification in the double-pass active mirror(AM)geometry.Three types of overlap condition are studied,and the spatiotemporal scaling under the four-pulse overlapping(4 PO)c...We present a spatiotemporal model of pulse amplification in the double-pass active mirror(AM)geometry.Three types of overlap condition are studied,and the spatiotemporal scaling under the four-pulse overlapping(4 PO)condition is fully characterized for the first time,by mapping the temporal and spatial segments of beam to the instantaneous gain windows.Furthermore,the influence of spatiotemporal overlaps on the amplified energy,pulse distortion and intensity profile is unraveled for both AM and zigzag configurations.The model,verified by excellent agreement between the predicted and measured results,can be a powerful tool for designing and optimizing high energy multi-pass solid-state laser amplifiers with AM,zigzag and other geometries.展开更多
A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd dope...A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd doped. When the pump energy was 26.8 J and the input energy was 0.3 J, the output pulse energy reached 5.4 J, and the pulse width of 11.3 ns at a 5 Hz repetition rate was obtained for the two gain modules in three-pass amplification, with corresponding optical-to-optical efficiency of 21.2%. The beam quality was measured as M_x^2=2.48 and M_y^2=2.43 in horizontal and vertical directions, respectively.展开更多
文摘The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has met the engineering requirements on the ground will change, seriously affecting the imaging quality. In order to eliminate the influence of gravity and to ensure the consistency of space and ground, gravity unloading must be performed. In order to meet the requirements of processing and testing for the large aperture space mirror in the state of vertical optical axis, a universal gravity unloading device was proposed. It was an active support and used air cylinders to provide accurate unloading force. First, the design flow of gravity unloading was introduced;then the detailed design of the mechanical structure and control system was given;then the performance parameters of the two types of cylinders were tested and compared, including the force-pressure relationship curve and the force-position relationship curve;finally, the experimental verification of the gravity unloading device was carried out;for a mirror with an aperture of ?2100 mm, the gravity unloading device was designed and a vertical detection optical path was built. The test results showed that by using this gravity unloading device, the actual processing surface accuracy of the mirror was better than 1/50λ-RMS, which met the application requirement of the optical system. Thus, it can be seen that using this gravity unloading device can effectively unload the gravity of the mirror and realize the accurate processing and measurement of the mirror surface. .
基金supported by funds from the Jaxing City Science and Technology Plan Project of Zhejiang province(2014AY21031-9)Zhejiang Provincial National Science Foundation of China(LY12H17004)the National Natural Science Foundation of China(81201504).
文摘Objective:To evaluate the effects of action observation therapy,which is based on mirror neuron theory,on upper limb function and activities of daily living in patients with stroke.Methods:Sixty-one patients with stroke were randomly divided into two groups;those in the control group received routine rehabilitation treatment and nursing,whereas those in the experimental group additionally received eight weeks of action observation therapy for 30 min,six times per week.Patients receiving action observation therapy watched videos depicting a model performing specific motor actions typically performed in daily life before enacting the same actions themselves.All patients were assessed using the FugleMeyer assessment,Barthel index and the modified Ashworth scale at baseline and at eight weeks,after treatment.Results:After the eight weeks of treatment,both groups of patients exhibited significant improvement in all the measurements(all p<0.05).Furthermore,the FugleMeyer assessment,Barthel index and modified Ashworth scale scores were significantly higher in the experimental group compared to the control group(all p<0.05).Conclusion:Action observation therapy significantly improves upper extremity motor function and performance of activities of daily living,and alleviates upper limb spasticity in patients with stroke.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(No.2017R1D1A1B03033985to MYL)+1 种基金the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(No.2018R1A5A2025272to MYL)
文摘Mirror neuron system can be activated by observation and execution of an action.It has an important function of action understanding.We investigated brain activations in humans by observing the strength of a hand grasp using functional magnetic resonance imaging.Twenty right-handed healthy individuals,consisting of 10 males and 10 females,aged 22.40 ± 2.04 years,were recruited into this study from September to November 2017 via posters.Light hand grasp task video showed a hand lightly grasping and releasing a ball repeatedly.Powerful hand grasp task video showed a hand tightly grasping and releasing a ball repeatedly.Functional magnetic resonance imaging block design paradigm comprised five stimulation blocks alternating with five baseline blocks.Stimulation blocks were presented with two stimulus tasks,consisting of a light grasp and a powerful grasp.Region of interest was defined around the inferior parietal lobule,inferior frontal gyrus,and superior temporal sulcus which have been called mirror neuron system.The inferior parietal lobule,fusiform,postcentral,occipital,temporal,and frontal gyri were activated during light and powerful grasp tasks.The BOLD signal response of a powerful grasp was stronger than that of a light grasp.These results suggest that brain activation of the inferior parietal lobule,which is the core brain region of the mirror neuron system,was stronger in the powerful grasp task than in the light grasp task.We believe that our results might be helpful for instructing rehabilitation of brain injury.This study was approved by the Institutional Review Board of Daegu Oriental Hospital of Daegu Haany University on September 8,2017 (approval No.DHUMC-D-17020-PRO-01).
基金National Key Research and Development Program of China(No.2017YFB0405100)National Natural Science Foundation of China(No.61975087)Beijing Young Talents Support Project(No.2017000020124G044)。
文摘We present a spatiotemporal model of pulse amplification in the double-pass active mirror(AM)geometry.Three types of overlap condition are studied,and the spatiotemporal scaling under the four-pulse overlapping(4 PO)condition is fully characterized for the first time,by mapping the temporal and spatial segments of beam to the instantaneous gain windows.Furthermore,the influence of spatiotemporal overlaps on the amplified energy,pulse distortion and intensity profile is unraveled for both AM and zigzag configurations.The model,verified by excellent agreement between the predicted and measured results,can be a powerful tool for designing and optimizing high energy multi-pass solid-state laser amplifiers with AM,zigzag and other geometries.
文摘A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd doped. When the pump energy was 26.8 J and the input energy was 0.3 J, the output pulse energy reached 5.4 J, and the pulse width of 11.3 ns at a 5 Hz repetition rate was obtained for the two gain modules in three-pass amplification, with corresponding optical-to-optical efficiency of 21.2%. The beam quality was measured as M_x^2=2.48 and M_y^2=2.43 in horizontal and vertical directions, respectively.
