This work was focused on the model-based design method of two-axis four-actuator(TAFA) fast steering mirror system(FSM), in order to improve the design efficiency. The structure and operation principle commonality of ...This work was focused on the model-based design method of two-axis four-actuator(TAFA) fast steering mirror system(FSM), in order to improve the design efficiency. The structure and operation principle commonality of normal TAFA FSM were investigated. Based on the structure and the commonality, the conditions of single-axis idea, high-frequency resonance and coupling were modeled gradually. Combining these models, a holonomic system model was established to reflect and predict the performance of TAFA FSM. A model-based design method was proposed based on the holonomic system model. The design flow and design concept of the method were described. In accordance with the method, a TAFA FSM was designed. Simulations and experiments of the FSM were done, and the results of them were compared. The compared results indicate that the holonomic system model can well reflect and predict the performance of TAFA FSM. The bandwidth of TAFA FSM is more than 250 Hz; adjust time is less than 15 ms;overshoot is less than 8%; position accuracy is better than 10 μrad; the FSM prototype can satisfy the requirements.展开更多
The TMT tertiary mirror system is facing a challenge of a rigid requirement for image jitter performance. The design of the mechanical structure and the devices selection will affect the image motion jitter for the te...The TMT tertiary mirror system is facing a challenge of a rigid requirement for image jitter performance. The design of the mechanical structure and the devices selection will affect the image motion jitter for the telescope observation. In this paper, a jitter test experiment has been done on a similar configuration telescope to support the design of the TMT tertiary mirror system. A method of position tracking is explored for jitter test using a 32bit absolute angle encoder. Several kinds of disturbance sources which can affect the system jitter have been discussed. According to the experimental results, during the low speed tracking, the jitter is less than 10 milliarcsec RMS, and the design of the system can meet the jitter requirement the TMT tertiary mirror system. The NFIRAOS error rejection transfer function is given for the further correction of jitter.展开更多
To solve the rate-dependent hysteresis compensation problem in fast steering mirror(FSM) systems, an improved Prandtl-Ishlinskii(P-I) model is proposed in this paper. The proposed model is formulated by employing a li...To solve the rate-dependent hysteresis compensation problem in fast steering mirror(FSM) systems, an improved Prandtl-Ishlinskii(P-I) model is proposed in this paper. The proposed model is formulated by employing a linear density function into the STOP operator. By this way, the proposed model has a relatively simple mathematic format, which can be applied to compensate the rate-dependent hysteresis directly. Adaptive differential evolution algorithm is utilized to obtain the accurate parameters of the proposed model. A fast steering mirror control system is established to demonstrate the validity and feasibility of the improved P-I model. Comparative experiments with different input signals are performed and analyzed, and the results show that the proposed model not only suppresses the rate-dependent hysteresis effectively, but also obtains high tracking precision.展开更多
An advanced deformable Kirkpatrick–Baez(K-B)mirror system was developed,equipped with high-speed piezoelectric actuators,and designed to induce beam decoherence and significantly enhance the quality of X-ray imaging ...An advanced deformable Kirkpatrick–Baez(K-B)mirror system was developed,equipped with high-speed piezoelectric actuators,and designed to induce beam decoherence and significantly enhance the quality of X-ray imaging by minimizing undesirable speckles in synchrotron radiation or free-electron laser facilities.Each individual mirror is engineered with 36 independent piezoelectric actuators that operate in a randomized manner,orchestrating the mirror surface to oscillate at a high frequency up to 100 kHz.Through in situ imaging single-slit diffraction measurement,it has been demonstrated that this high-frequency-vibration mirror system is pivotal in disrupting the coherent nature,thereby diminishing speckle formation.The impact of the K-B mirror system is profound,with the capability to reduce the image contrast to as low as 0.04,signifying a substantial reduction in speckle visibility.Moreover,the coherence of the X-ray beam is significantly lowered from an initial value exceeding 80%to 13%.展开更多
Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number...Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number of actuators,and there are problems with structural coupling and large temperature increases in their internal coils.Additionally,parameters of the traditional proportional integral derivative(PID)control cannot be adjusted in real-time to adapt to system changes.These problems can be addressed by introducing fuzzy control methods.A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process,and a prototype platform has been established to verify the effectiveness and robustness of this process.Experimental tests compare the control performance of traditional and fuzzy proportional integral derivative(Fuzzy-PID)controllers,showing that,in system step response tests,the fuzzy control system reduces rise time by 20.25%,decreases overshoot by 78.24%,and shortens settling time by 67.59%.In disturbance rejection experiments,fuzzy control achieves a 46.09%reduction in the maximum deviation,indicating stronger robustness.The Fuzzy-PID controller,based on table lookup,outperforms the standard controller significantly,showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.展开更多
[Objectives]To investigate the evidence-based effect of virtual reality-based mirror therapy system(VR-MT)on upper extremity function among stroke patients.[Methods]A systematic electronic searching of the Medline,Pub...[Objectives]To investigate the evidence-based effect of virtual reality-based mirror therapy system(VR-MT)on upper extremity function among stroke patients.[Methods]A systematic electronic searching of the Medline,PubMed,Web of Science and CNKI was initially performed up to June 10,2024.The risk of bias of the included studies was evaluated using RevMan 5.4 software based on the Cochrane Handbook for Systematic Reviews.The random-effects model or fixed-effects models was employed to estimate the standardized mean difference(SMD).The subgroup analyses were conducted exploring theVR-MT type(immersive or non-immersive)and comparing with MT or control group.[Results]In total 8 studies with a total of 273 stroke patients were included in this review.The pooled analysis of these trials showed a statistically significant enhancement inFMA-UE scores(6 studies,SMD=0.72,[95%CI 0.37 to 1.06];P<0.0001,I^(2)=31%)and Box and Block Test(BBT)(3 studies,SMD=0.49,[95%C/0.05 to 0.93];P=0.03,I^(2)=0%),rather than Manual Function Test(MFT)scores(3 studies,SMD=0.38,[95%CI-0.09 to 0.84];P=0.11,I^(2)=0%)following the application of reality-based mirror therapy.Additionally,the subgroup analysis results indicated that immersive VR-MT can significantly improve FMA-UE(5studies,SMD=0.73,[95%CI 0.24 to 1.23];P=0.004,I^(2)=43%).In contrast,the overall effect of non-immersive VR-MT was non-significant(2 studies,SMD=0.33,[95%CI-0.69 to 1.34];P=0.53,I^(2)=72%).[Conclusions]In this systematic review and meta-analysis,our findings indicate that immersiveVR-MT has the potential to improve upper extremity function among stroke patients.展开更多
Animated block-buster Ne Zha2 is the first non-Hollywood movie to be part of the.top 10 list and is already the highest-grossing animated movie of all time.If Ne Zha 2 has a bigger international rollout,it will be int...Animated block-buster Ne Zha2 is the first non-Hollywood movie to be part of the.top 10 list and is already the highest-grossing animated movie of all time.If Ne Zha 2 has a bigger international rollout,it will be interesting to see how far its initial momentum can take it.展开更多
The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass formula.We observe that for heavy nuclei at the neutron drip line,the Coulomb e...The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass formula.We observe that for heavy nuclei at the neutron drip line,the Coulomb energy heightened by an aug-mented charge could not be mitigated completely by symmetry energy because of isospin asymmetry saturation but is resisted complementally by strong nuclear deformation.The positions of saltation for the difference in proton numbers between two neighboring nuclei at the neutron drip line,and the isospin asymmetry of the neutron drip-line nucleus as a function of the neutron number distinctly correspond to the known magic numbers,which can serve as a reference to verify the undeter-mined neutron magic number.Through fitting of the binding energy difference between mirror nuclei(BEDbMN),a set of Coulomb energy coefficients with greater accuracy is obtained.A high-precision description of the BEDbMN is useful for accurately determining the experimentally unknown mass of the nucleus close to the proton drip line if the mass of its mirror nucleus is measured experimentally.展开更多
Computer-aided diagnosis(CAD)can detect tuberculosis(TB)cases,providing radiologists with more accurate and efficient diagnostic solutions.Various noise information in TB chest X-ray(CXR)images is a major challenge in...Computer-aided diagnosis(CAD)can detect tuberculosis(TB)cases,providing radiologists with more accurate and efficient diagnostic solutions.Various noise information in TB chest X-ray(CXR)images is a major challenge in this classification task.This study aims to propose a model with high performance in TB CXR image detection named multi-scale input mirror network(MIM-Net)based on CXR image symmetry,which consists of a multi-scale input feature extraction network and mirror loss.The multi-scale image input can enhance feature extraction,while the mirror loss can improve the network performance through self-supervision.We used a publicly available TB CXR image classification dataset to evaluate our proposed method via 5-fold cross-validation,with accuracy,sensitivity,specificity,positive predictive value,negative predictive value,and area under curve(AUC)of 99.67%,100%,99.60%,99.80%,100%,and 0.9999,respectively.Compared to other models,MIM-Net performed best in all metrics.Therefore,the proposed MIM-Net can effectively help the network learn more features and can be used to detect TB in CXR images,thus assisting doctors in diagnosing.展开更多
In this note we describe a logarithmic version of mirror Landau-Ginzburg model for semi-projective toric manifolds and show in an elementary and explicit way that the state space ring of the Landau-Ginzburg mirror is ...In this note we describe a logarithmic version of mirror Landau-Ginzburg model for semi-projective toric manifolds and show in an elementary and explicit way that the state space ring of the Landau-Ginzburg mirror is isomorphic to the C-valued cohomology of the toric manifold.展开更多
High-power laser systems have opened new frontiers in scientifi research and have revolutionized various scientifi fields offering unprecedented capabilities for understanding fundamental physics and allowing unique a...High-power laser systems have opened new frontiers in scientifi research and have revolutionized various scientifi fields offering unprecedented capabilities for understanding fundamental physics and allowing unique applications.This paper details the successful commissioning of the 1 PW experimental area at the Extreme Light Infrastructure–Nuclear Physics(ELI-NP)facility in Romania,using both of the available laser arms.The experimental setup featured a short focal parabolic mirror to accelerate protons through the target normal sheath acceleration mechanism.Detailed experiments were conducted using various metallic and diamond-like carbon targets to investigate the dependence of the proton acceleration on different laser parameters.Furthermore,the paper discusses the critical role of the laser temporal profil in optimizing proton acceleration,supported by hydrodynamic simulations that are correlated with experimental outcomes.The finding underscore the potential of the ELI-NP facility to advance research in laser–plasma physics and contribute significantl to high-energy physics applications.The results of this commissioning establish a strong foundation for experiments by future users.展开更多
In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,p...In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,parallel-connected independent-excitation direct-current(DC)motors for mud pumps,that are supplied by a single power converter.This configuration results in electrical power imbalance,thus reducing its efficiency.This paper investigates this power imbalance issue in such legacy DC mud pump drive systems and offers an innovative solution in the form of a closed-loop control system for electrical load balancing.The paper first analyzes the drilling fluid circulation and electrical drive layout to develop an analytical model that can be used for electrical load balancing and related energy efficiency improvements.Based on this analysis,a feedback control system(so-called“current mirror”control system)is designed to balance the electrical load(i.e.,armature currents)of parallel-connected DC machines by adjusting the excitation current of one of the DC machines,thus mitigating the power imbalance of the electrical drive.Theproposed control systemeffectiveness has been validated,first through simulations,followed by experimental testing on a deep drilling rig during commissioning and field tests.The results demonstrate the practical viability of the proposed“current mirror”control system that can effectively and rather quickly equalize the armature currents of both DC machines in a parallel-connected electrical drive,and thus balance both the electrical and mechanical load of individual DC machines under realistic operating conditions of the mud pump electrical drive.展开更多
Mirror neuron system （MNS） represents one past decade, and it has been found to involve in multiple of the most important discoveries of cognitive neuroscience in the aspects of brain functions including action unde...Mirror neuron system （MNS） represents one past decade, and it has been found to involve in multiple of the most important discoveries of cognitive neuroscience in the aspects of brain functions including action understanding, imitation, language understanding, empathy, action prediction and speech evolution. This manuscript reviewed the function of MNS in action understanding as well as language evolution, and specifically assessed its roles as the bridge from body language to fluent speeches. Then we discussed the speech defects of autism patients due to the disruption of MNS. Finally, given that MNS is plastic in adult brain, we proposed MNS targeted therapy provides an efficient rehabilitation approach for brain damages conditions as well as autism patients.展开更多
This paper presents the design of an experimental battlefield dynamic scanning and staring imaging system based on a fast steering mirror(FSM), which is capable of real-time monitoring of hot targets and wide-area rec...This paper presents the design of an experimental battlefield dynamic scanning and staring imaging system based on a fast steering mirror(FSM), which is capable of real-time monitoring of hot targets and wide-area reconnaissance of hot regions. First,the working principle and working sequence of the FSM are briefly analyzed. The mathematical model of the FSM system is built by modeling its dynamic and electrical properties, and the rationality of the model is validated by means of model identification. Second,the influence of external sources of disturbance such as the carrier and moment on the control precision of the FSM is effectively suppressed by the jointly controlling of proportional integral(PI)and disturbance observer(DOB), thus realizing a high precision and strong robustness control of the FSM system. Then, this paper designs an experimental prototype and introduces a special optical structure to enable the infrared camera to share the FSM with the visible light camera. Finally, the influence of the velocity difference between the mirror of the FSM and the rotating platform on the imaging quality of the system is experimentally analyzed by using the image sharpness evaluation method based on point sharpness. A good dynamic scanning and staring imaging result is achieved when the velocity of these two components correspond.展开更多
We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors （DMs） in a woofer-tweeter adaptive optics system. This algorithm can directly use the woofer＇s response matrix mea...We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors （DMs） in a woofer-tweeter adaptive optics system. This algorithm can directly use the woofer＇s response matrix measured from a Shack-Hartmann wave-front sensor to construct a slope-based orthogonal basis, and then selectively distribute the large- amplitude low-order aberration to woofer DM and the remaining aberration to tweeter DM through the slope-based orthogonal basis. At the same moment, in order to avoid the two DMs generating opposite compensation, a constraint matrix used to reset tweeter control vector is convenient to be calculated with the slope-based orthogonal basis. Numeral simulation demonstrates that this algorithm has a good performance to control the adaptive optics system with dual DMs simultaneously. Compared with the typical decoupling algorithm, this algorithm can take full use of the compensation ability of woofer DM and release the stroke of tweeter DM to compensate high-order aberration. More importantly, it does not need to measure the accurate shape of tweeter＇s influence function and keeps better performance of restraining the coupling error with the continuous-dynamic aberration.展开更多
The mirror neuron system （MNS） was first discovered in non-human primates; these neurons fire when a monkey performs an action or observes another monkey （or even some people） performing that same action. Recent f...The mirror neuron system （MNS） was first discovered in non-human primates; these neurons fire when a monkey performs an action or observes another monkey （or even some people） performing that same action. Recent findings have suggested that neural rehabilitation might be achieved through the activation of the MNS in patients after stroke. We propose two major mechanisms （one involving adult neurogenesis and another involving brain-derived neurotrophic factor） that may underlie the activation, modulation and experience-dependent plasticity in the MNS, for further study on promoting central nerve functional reconstruction and rehabilitation of patients with central nervous system injury.展开更多
A modeling method is proposed for a dynamic fast steering mirror(FSM) system with dual inputs and dual outputs. A physical model of the FSM system is derived based on first principles, describing the dynamics and coup...A modeling method is proposed for a dynamic fast steering mirror(FSM) system with dual inputs and dual outputs. A physical model of the FSM system is derived based on first principles, describing the dynamics and coupling between the inputs and outputs of the FSM system. The physical model is then represented in a state-space form. Unknown parameters in the state-space model are identified by the subspace identification algorithm, based on the measured input-output data of the FSM system. The accuracy of the state-space model is evaluated by comparing the model estimates with measurements. The variance-accounted-for value of the state-space model is better than 97%, not only for the modeling data but also for the validation data set, indicating high accuracy of the model. Comparison is also made between the proposed dynamic model and the conventional static model, where improvement in model accuracy is clearly observed. The model identified by the proposed method can be used for optimal controller design for closed-loop FSM systems. The modeling method is also applicable to FSM systems with similar structures.展开更多
Previous studies have demonstrated that hand shadows may activate the motor cortex associated with the mirror neuron system in human brain. However, there is no evidence of activity of the human mirror neuron system d...Previous studies have demonstrated that hand shadows may activate the motor cortex associated with the mirror neuron system in human brain. However, there is no evidence of activity of the human mirror neuron system during the observation of intransitive movements by shadows and line drawings of hands. This study examined the suppression of electroencephalography mu waves （8-13 Hz） induced by observation of stimuli in 18 healthy students. Three stimuli were used： real hand actions, hand shadow actions and actions made by line drawings of hands. The results showed significant desynchronization of the mu rhythm （＂mu suppression＂） across the sensodmotor cortex （recorded at C3, Cz and C4）, the frontal cortex （recorded at F3, Fz and F4） and the central and right posterior parietal cortex （recorded at Pz and P4） under all three conditions. Our experimental findings suggest that the observation of ＂impoverished hand actions＂, such as intransitive movements of shadows and line drawings of hands, is able to activate widespread cortical areas related to the putative human mirror neuron system.展开更多
By using a rotating hexahedral mirror placed in front of the objective lens and two sets of visible and ultraviolet monochromators coupled with a branchy quartz fiber bundle, a space-time resolved spectroscopic system...By using a rotating hexahedral mirror placed in front of the objective lens and two sets of visible and ultraviolet monochromators coupled with a branchy quartz fiber bundle, a space-time resolved spectroscopic system has been developed on the HT-7 superconducting tokamak. A center monitoring system has been used including a Helium-Neon laser and a photodiode detector to indicate the absolute position of the measurement in order to reduce the error caused by the uncertain emissive position of the plasma. By using the asymmetric Abel inversion, the space-time resolved local emission coefficients of the spectroscopic line emissions have been obtained. Presented in this article are simultaneous measurements of two spectral line emissions such as CV-227.1 nm and OV-278.1 nm during a single plasma discharge on the HT-7. Experimental results indicate that the time resolution is better than 3 ms, the space resolution is better than 1.5cm, the ratio of signal to background is better than 10：1, and the relative error of chord-integrated emission profile is less than 10%. Compared to traditional multichannel detecting systems, this system has considerably improved measurement efficiency, reduced uncertainty, and is therefore suitable for transport studies of global particles and impurities.展开更多
We introduce an asymmetrical mirror design to a 140 GHz TE_（22,6） quasi-optical（QO） mode converter system to correct the asymmetry of the beam＇s field distribution caused by the Denisov launcher. By such optimiza...We introduce an asymmetrical mirror design to a 140 GHz TE_（22,6） quasi-optical（QO） mode converter system to correct the asymmetry of the beam＇s field distribution caused by the Denisov launcher. By such optimization, the output beam with better symmetrical distribution is obtained at the system＇s output window. Based on the calculated results,the QO mode converter system＇s performance is already satisfying without iterative phase correction. Scalar and vector correlation coefficients between the output beam and the fundamental Gaussian beam are respectively 98.4% and 93.0%,while the total power transmission efficiency of the converter system is 94.4%. The assistance of optical ray tracing to the design of such QO mode converters is introduced and discussed as well.展开更多
基金Projects(51135009)supported by the National Natural Science Foundation of China
文摘This work was focused on the model-based design method of two-axis four-actuator(TAFA) fast steering mirror system(FSM), in order to improve the design efficiency. The structure and operation principle commonality of normal TAFA FSM were investigated. Based on the structure and the commonality, the conditions of single-axis idea, high-frequency resonance and coupling were modeled gradually. Combining these models, a holonomic system model was established to reflect and predict the performance of TAFA FSM. A model-based design method was proposed based on the holonomic system model. The design flow and design concept of the method were described. In accordance with the method, a TAFA FSM was designed. Simulations and experiments of the FSM were done, and the results of them were compared. The compared results indicate that the holonomic system model can well reflect and predict the performance of TAFA FSM. The bandwidth of TAFA FSM is more than 250 Hz; adjust time is less than 15 ms;overshoot is less than 8%; position accuracy is better than 10 μrad; the FSM prototype can satisfy the requirements.
基金Sponsored by the National Natural Science Foundation of China( Grant No.11403022).
文摘The TMT tertiary mirror system is facing a challenge of a rigid requirement for image jitter performance. The design of the mechanical structure and the devices selection will affect the image motion jitter for the telescope observation. In this paper, a jitter test experiment has been done on a similar configuration telescope to support the design of the TMT tertiary mirror system. A method of position tracking is explored for jitter test using a 32bit absolute angle encoder. Several kinds of disturbance sources which can affect the system jitter have been discussed. According to the experimental results, during the low speed tracking, the jitter is less than 10 milliarcsec RMS, and the design of the system can meet the jitter requirement the TMT tertiary mirror system. The NFIRAOS error rejection transfer function is given for the further correction of jitter.
基金supported by the Twelfth Five Year Research Project(No.2015syhz0023)
文摘To solve the rate-dependent hysteresis compensation problem in fast steering mirror(FSM) systems, an improved Prandtl-Ishlinskii(P-I) model is proposed in this paper. The proposed model is formulated by employing a linear density function into the STOP operator. By this way, the proposed model has a relatively simple mathematic format, which can be applied to compensate the rate-dependent hysteresis directly. Adaptive differential evolution algorithm is utilized to obtain the accurate parameters of the proposed model. A fast steering mirror control system is established to demonstrate the validity and feasibility of the improved P-I model. Comparative experiments with different input signals are performed and analyzed, and the results show that the proposed model not only suppresses the rate-dependent hysteresis effectively, but also obtains high tracking precision.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFA1608604)the National Natural Science Foundation of China(Grant Nos.12175294 and 12235011)the Natural Science Foundation of Shanghai Municipality(Grant No.21ZR1471500).
文摘An advanced deformable Kirkpatrick–Baez(K-B)mirror system was developed,equipped with high-speed piezoelectric actuators,and designed to induce beam decoherence and significantly enhance the quality of X-ray imaging by minimizing undesirable speckles in synchrotron radiation or free-electron laser facilities.Each individual mirror is engineered with 36 independent piezoelectric actuators that operate in a randomized manner,orchestrating the mirror surface to oscillate at a high frequency up to 100 kHz.Through in situ imaging single-slit diffraction measurement,it has been demonstrated that this high-frequency-vibration mirror system is pivotal in disrupting the coherent nature,thereby diminishing speckle formation.The impact of the K-B mirror system is profound,with the capability to reduce the image contrast to as low as 0.04,signifying a substantial reduction in speckle visibility.Moreover,the coherence of the X-ray beam is significantly lowered from an initial value exceeding 80%to 13%.
基金supported by the National Key R&D Program of China (2022YFA1603001,2021YFC2801402)the National Nature Science Foundation of China (12073053)the Science and Technology Plan of Inner Mongolia (2021GG0245).
文摘Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number of actuators,and there are problems with structural coupling and large temperature increases in their internal coils.Additionally,parameters of the traditional proportional integral derivative(PID)control cannot be adjusted in real-time to adapt to system changes.These problems can be addressed by introducing fuzzy control methods.A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process,and a prototype platform has been established to verify the effectiveness and robustness of this process.Experimental tests compare the control performance of traditional and fuzzy proportional integral derivative(Fuzzy-PID)controllers,showing that,in system step response tests,the fuzzy control system reduces rise time by 20.25%,decreases overshoot by 78.24%,and shortens settling time by 67.59%.In disturbance rejection experiments,fuzzy control achieves a 46.09%reduction in the maximum deviation,indicating stronger robustness.The Fuzzy-PID controller,based on table lookup,outperforms the standard controller significantly,showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.
文摘[Objectives]To investigate the evidence-based effect of virtual reality-based mirror therapy system(VR-MT)on upper extremity function among stroke patients.[Methods]A systematic electronic searching of the Medline,PubMed,Web of Science and CNKI was initially performed up to June 10,2024.The risk of bias of the included studies was evaluated using RevMan 5.4 software based on the Cochrane Handbook for Systematic Reviews.The random-effects model or fixed-effects models was employed to estimate the standardized mean difference(SMD).The subgroup analyses were conducted exploring theVR-MT type(immersive or non-immersive)and comparing with MT or control group.[Results]In total 8 studies with a total of 273 stroke patients were included in this review.The pooled analysis of these trials showed a statistically significant enhancement inFMA-UE scores(6 studies,SMD=0.72,[95%CI 0.37 to 1.06];P<0.0001,I^(2)=31%)and Box and Block Test(BBT)(3 studies,SMD=0.49,[95%C/0.05 to 0.93];P=0.03,I^(2)=0%),rather than Manual Function Test(MFT)scores(3 studies,SMD=0.38,[95%CI-0.09 to 0.84];P=0.11,I^(2)=0%)following the application of reality-based mirror therapy.Additionally,the subgroup analysis results indicated that immersive VR-MT can significantly improve FMA-UE(5studies,SMD=0.73,[95%CI 0.24 to 1.23];P=0.004,I^(2)=43%).In contrast,the overall effect of non-immersive VR-MT was non-significant(2 studies,SMD=0.33,[95%CI-0.69 to 1.34];P=0.53,I^(2)=72%).[Conclusions]In this systematic review and meta-analysis,our findings indicate that immersiveVR-MT has the potential to improve upper extremity function among stroke patients.
文摘Animated block-buster Ne Zha2 is the first non-Hollywood movie to be part of the.top 10 list and is already the highest-grossing animated movie of all time.If Ne Zha 2 has a bigger international rollout,it will be interesting to see how far its initial momentum can take it.
基金supported by the Ministry of Science and Technology of China(No.2022YFE0103400)Natural Science Foundation of Guangxi Province(No.2021GXNSFAA196052)National Natural Science Foundation of China(No.11965004).
文摘The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass formula.We observe that for heavy nuclei at the neutron drip line,the Coulomb energy heightened by an aug-mented charge could not be mitigated completely by symmetry energy because of isospin asymmetry saturation but is resisted complementally by strong nuclear deformation.The positions of saltation for the difference in proton numbers between two neighboring nuclei at the neutron drip line,and the isospin asymmetry of the neutron drip-line nucleus as a function of the neutron number distinctly correspond to the known magic numbers,which can serve as a reference to verify the undeter-mined neutron magic number.Through fitting of the binding energy difference between mirror nuclei(BEDbMN),a set of Coulomb energy coefficients with greater accuracy is obtained.A high-precision description of the BEDbMN is useful for accurately determining the experimentally unknown mass of the nucleus close to the proton drip line if the mass of its mirror nucleus is measured experimentally.
基金supported by the Joint Fund of the Ministry of Education for Equipment Pre-research(No.8091B0203)National Key Research and Development Program of China(No.2020YFC2008700)。
文摘Computer-aided diagnosis(CAD)can detect tuberculosis(TB)cases,providing radiologists with more accurate and efficient diagnostic solutions.Various noise information in TB chest X-ray(CXR)images is a major challenge in this classification task.This study aims to propose a model with high performance in TB CXR image detection named multi-scale input mirror network(MIM-Net)based on CXR image symmetry,which consists of a multi-scale input feature extraction network and mirror loss.The multi-scale image input can enhance feature extraction,while the mirror loss can improve the network performance through self-supervision.We used a publicly available TB CXR image classification dataset to evaluate our proposed method via 5-fold cross-validation,with accuracy,sensitivity,specificity,positive predictive value,negative predictive value,and area under curve(AUC)of 99.67%,100%,99.60%,99.80%,100%,and 0.9999,respectively.Compared to other models,MIM-Net performed best in all metrics.Therefore,the proposed MIM-Net can effectively help the network learn more features and can be used to detect TB in CXR images,thus assisting doctors in diagnosing.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.12201314).
文摘In this note we describe a logarithmic version of mirror Landau-Ginzburg model for semi-projective toric manifolds and show in an elementary and explicit way that the state space ring of the Landau-Ginzburg mirror is isomorphic to the C-valued cohomology of the toric manifold.
基金supported by the Extreme Light Infrastructure–Nuclear Physics(ELI-NP)PhaseⅡa project co-finance by the Romanian Government and the European Union through the European Regional Development Fund,by the Romanian Ministry of Education and Research CNCS-UEFISCDI(Project No.PN-ⅡIP4-IDPCCF-2016-0164)+1 种基金Nucleu Projects(Grant No.PN 23210105 and 19060105)supports ELI-NP through IOSIN funds as a Facility of National Interest。
文摘High-power laser systems have opened new frontiers in scientifi research and have revolutionized various scientifi fields offering unprecedented capabilities for understanding fundamental physics and allowing unique applications.This paper details the successful commissioning of the 1 PW experimental area at the Extreme Light Infrastructure–Nuclear Physics(ELI-NP)facility in Romania,using both of the available laser arms.The experimental setup featured a short focal parabolic mirror to accelerate protons through the target normal sheath acceleration mechanism.Detailed experiments were conducted using various metallic and diamond-like carbon targets to investigate the dependence of the proton acceleration on different laser parameters.Furthermore,the paper discusses the critical role of the laser temporal profil in optimizing proton acceleration,supported by hydrodynamic simulations that are correlated with experimental outcomes.The finding underscore the potential of the ELI-NP facility to advance research in laser–plasma physics and contribute significantl to high-energy physics applications.The results of this commissioning establish a strong foundation for experiments by future users.
文摘In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,parallel-connected independent-excitation direct-current(DC)motors for mud pumps,that are supplied by a single power converter.This configuration results in electrical power imbalance,thus reducing its efficiency.This paper investigates this power imbalance issue in such legacy DC mud pump drive systems and offers an innovative solution in the form of a closed-loop control system for electrical load balancing.The paper first analyzes the drilling fluid circulation and electrical drive layout to develop an analytical model that can be used for electrical load balancing and related energy efficiency improvements.Based on this analysis,a feedback control system(so-called“current mirror”control system)is designed to balance the electrical load(i.e.,armature currents)of parallel-connected DC machines by adjusting the excitation current of one of the DC machines,thus mitigating the power imbalance of the electrical drive.Theproposed control systemeffectiveness has been validated,first through simulations,followed by experimental testing on a deep drilling rig during commissioning and field tests.The results demonstrate the practical viability of the proposed“current mirror”control system that can effectively and rather quickly equalize the armature currents of both DC machines in a parallel-connected electrical drive,and thus balance both the electrical and mechanical load of individual DC machines under realistic operating conditions of the mud pump electrical drive.
基金Sci-ence Foundation of Ministry of Education of China (No.FBB011469)
文摘Mirror neuron system （MNS） represents one past decade, and it has been found to involve in multiple of the most important discoveries of cognitive neuroscience in the aspects of brain functions including action understanding, imitation, language understanding, empathy, action prediction and speech evolution. This manuscript reviewed the function of MNS in action understanding as well as language evolution, and specifically assessed its roles as the bridge from body language to fluent speeches. Then we discussed the speech defects of autism patients due to the disruption of MNS. Finally, given that MNS is plastic in adult brain, we proposed MNS targeted therapy provides an efficient rehabilitation approach for brain damages conditions as well as autism patients.
基金supported by the National Defense Pre-research Project of China during the 12th Five-year Plan Period(4040570201)Innovation Project of Military Academy(ZYX14060014)
文摘This paper presents the design of an experimental battlefield dynamic scanning and staring imaging system based on a fast steering mirror(FSM), which is capable of real-time monitoring of hot targets and wide-area reconnaissance of hot regions. First,the working principle and working sequence of the FSM are briefly analyzed. The mathematical model of the FSM system is built by modeling its dynamic and electrical properties, and the rationality of the model is validated by means of model identification. Second,the influence of external sources of disturbance such as the carrier and moment on the control precision of the FSM is effectively suppressed by the jointly controlling of proportional integral(PI)and disturbance observer(DOB), thus realizing a high precision and strong robustness control of the FSM system. Then, this paper designs an experimental prototype and introduces a special optical structure to enable the infrared camera to share the FSM with the visible light camera. Finally, the influence of the velocity difference between the mirror of the FSM and the rotating platform on the imaging quality of the system is experimentally analyzed by using the image sharpness evaluation method based on point sharpness. A good dynamic scanning and staring imaging result is achieved when the velocity of these two components correspond.
基金Project supported by the Key Scientific Equipment Development Project of China(Grant No.ZDYZ2013-2)the National High-Tech R&D Program of China(Grant Nos.G128201-G158201 and G128603-G158603)+2 种基金the Innovation Fund of Chinese Academy of Science(Grant No.CXJJ-16M208)the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe Outstanding Young Scientists,Chinese Academy of Sciences
文摘We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors （DMs） in a woofer-tweeter adaptive optics system. This algorithm can directly use the woofer＇s response matrix measured from a Shack-Hartmann wave-front sensor to construct a slope-based orthogonal basis, and then selectively distribute the large- amplitude low-order aberration to woofer DM and the remaining aberration to tweeter DM through the slope-based orthogonal basis. At the same moment, in order to avoid the two DMs generating opposite compensation, a constraint matrix used to reset tweeter control vector is convenient to be calculated with the slope-based orthogonal basis. Numeral simulation demonstrates that this algorithm has a good performance to control the adaptive optics system with dual DMs simultaneously. Compared with the typical decoupling algorithm, this algorithm can take full use of the compensation ability of woofer DM and release the stroke of tweeter DM to compensate high-order aberration. More importantly, it does not need to measure the accurate shape of tweeter＇s influence function and keeps better performance of restraining the coupling error with the continuous-dynamic aberration.
基金Science Foundation of Ministry of Education of China,No.FBB011469Hangzhou Municipal Natural Science Foundation, No.0737XP39Foundation of Hong Kong Special Administrative Region(RGC)
文摘The mirror neuron system （MNS） was first discovered in non-human primates; these neurons fire when a monkey performs an action or observes another monkey （or even some people） performing that same action. Recent findings have suggested that neural rehabilitation might be achieved through the activation of the MNS in patients after stroke. We propose two major mechanisms （one involving adult neurogenesis and another involving brain-derived neurotrophic factor） that may underlie the activation, modulation and experience-dependent plasticity in the MNS, for further study on promoting central nerve functional reconstruction and rehabilitation of patients with central nervous system injury.
基金supported by the National Natural Science Foundation of China(No.11304278)the National High-Tech R&D Program(863)of China(No.2014AA093400)
文摘A modeling method is proposed for a dynamic fast steering mirror(FSM) system with dual inputs and dual outputs. A physical model of the FSM system is derived based on first principles, describing the dynamics and coupling between the inputs and outputs of the FSM system. The physical model is then represented in a state-space form. Unknown parameters in the state-space model are identified by the subspace identification algorithm, based on the measured input-output data of the FSM system. The accuracy of the state-space model is evaluated by comparing the model estimates with measurements. The variance-accounted-for value of the state-space model is better than 97%, not only for the modeling data but also for the validation data set, indicating high accuracy of the model. Comparison is also made between the proposed dynamic model and the conventional static model, where improvement in model accuracy is clearly observed. The model identified by the proposed method can be used for optimal controller design for closed-loop FSM systems. The modeling method is also applicable to FSM systems with similar structures.
基金supported by the grants from the National Natural Science Foundation of China,No.60775019,60970062 and 61173116the Research Fund for the Doctoral Program of Higher Education of China,No.201100702110014
文摘Previous studies have demonstrated that hand shadows may activate the motor cortex associated with the mirror neuron system in human brain. However, there is no evidence of activity of the human mirror neuron system during the observation of intransitive movements by shadows and line drawings of hands. This study examined the suppression of electroencephalography mu waves （8-13 Hz） induced by observation of stimuli in 18 healthy students. Three stimuli were used： real hand actions, hand shadow actions and actions made by line drawings of hands. The results showed significant desynchronization of the mu rhythm （＂mu suppression＂） across the sensodmotor cortex （recorded at C3, Cz and C4）, the frontal cortex （recorded at F3, Fz and F4） and the central and right posterior parietal cortex （recorded at Pz and P4） under all three conditions. Our experimental findings suggest that the observation of ＂impoverished hand actions＂, such as intransitive movements of shadows and line drawings of hands, is able to activate widespread cortical areas related to the putative human mirror neuron system.
基金The project supported by National Natural Science Foundation of China (No. 10475078)
文摘By using a rotating hexahedral mirror placed in front of the objective lens and two sets of visible and ultraviolet monochromators coupled with a branchy quartz fiber bundle, a space-time resolved spectroscopic system has been developed on the HT-7 superconducting tokamak. A center monitoring system has been used including a Helium-Neon laser and a photodiode detector to indicate the absolute position of the measurement in order to reduce the error caused by the uncertain emissive position of the plasma. By using the asymmetric Abel inversion, the space-time resolved local emission coefficients of the spectroscopic line emissions have been obtained. Presented in this article are simultaneous measurements of two spectral line emissions such as CV-227.1 nm and OV-278.1 nm during a single plasma discharge on the HT-7. Experimental results indicate that the time resolution is better than 3 ms, the space resolution is better than 1.5cm, the ratio of signal to background is better than 10：1, and the relative error of chord-integrated emission profile is less than 10%. Compared to traditional multichannel detecting systems, this system has considerably improved measurement efficiency, reduced uncertainty, and is therefore suitable for transport studies of global particles and impurities.
基金Project supported by the National Natural Science Foundation of China(Grant No.61671032)
文摘We introduce an asymmetrical mirror design to a 140 GHz TE_（22,6） quasi-optical（QO） mode converter system to correct the asymmetry of the beam＇s field distribution caused by the Denisov launcher. By such optimization, the output beam with better symmetrical distribution is obtained at the system＇s output window. Based on the calculated results,the QO mode converter system＇s performance is already satisfying without iterative phase correction. Scalar and vector correlation coefficients between the output beam and the fundamental Gaussian beam are respectively 98.4% and 93.0%,while the total power transmission efficiency of the converter system is 94.4%. The assistance of optical ray tracing to the design of such QO mode converters is introduced and discussed as well.
