With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital ro...With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital role in the regulation of light in buildings,vehicles,and aircrafts.There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation.In this context,liquid crystals(LCs),owing to their rich responsiveness and unique optical properties,have been considered among the best candidates for advanced light protection materials.In this review,we provide an overview of advances in research on LC-based methods for protection against light.First,we introduce the characteristics of different light sources and their protection requirements.Second,we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection.In addition,we discuss current light protection strategies based on liquid crystal materials for different applications.Finally,we discuss the problems and shortcomings of current strategies.We propose several suggestions for the development of liquid crystal materials in the field of light protection.展开更多
A novel multispectral smart window has been proposed,which features dynamic modulation of light transmittance and effective shielding against electromagnetic microwave radiation.This design integrates liquid crystal d...A novel multispectral smart window has been proposed,which features dynamic modulation of light transmittance and effective shielding against electromagnetic microwave radiation.This design integrates liquid crystal dynamic scattering and dye doping techniques,enabling the dual regulation of transmittance and scattering within a singlelayer smart window.Additionally,the precise control of conductive film thickness ensures the attainment of robust microwave signal shielding.We present a theoretical model for ion movement in the presence of an alternating electric field,along with a novel approach to manipulate negative dielectric constant.The proposed model successfully enables a rapid transition between light transparent,absorbing and haze states,with an optimum drive frequency adjustable to approximately 300 Hz.Furthermore,the resistive design of the conductive layer effectively mitigates microwave radiation within the 2−18 GHz range.These findings offer an innovative perspective for future advancements in environmental construction.展开更多
Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working...Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working of the two principles.With aid of the wideband characteristic of bilateral complementary structure,we propose a strategy to design wideband absorptive elements with large reflection phase differences.For proof of concept,the proposed elements are arranged in a rectangular grid by optimizing scattering field distribution.The proposed diffusion metabsorber achieves over 20-dB scattering field reduction in the range of 8.5–20.3 GHz with good polarization stability and high angular insensitivity of up to±40°,which has been verified by real experiments.Furthermore,the proposed design strategy exhibits the potential to further reduce electromagnetic wave reflection,and the optical transparent characteristic is promising for window applications.展开更多
In this paper,a 3D meta-atom-based structure is constructed for the multifunctional compatible design of visible,infrared,and microwave.To achieve high performance,a novel dispersion tailoring strategy is proposed.Thr...In this paper,a 3D meta-atom-based structure is constructed for the multifunctional compatible design of visible,infrared,and microwave.To achieve high performance,a novel dispersion tailoring strategy is proposed.Through the incorporation of multiple controllable losses within the 3D meta-atom,the dispersion characteristics are tailored to the desired target region.The effectiveness of the strategy is verified with an error rate of less than5%.A proof-of-concept prototype is designed and fabricated,exhibiting high visible transparency,low infrared emission of 0.28,and microwave ultra-broadband absorption with a fractional bandwidth of 150%under 2.7 to18.7 GHz.This work contributes a novel design strategy for the development of high-performance multispectral stealth materials with wide applications.展开更多
The accuracy of a fracture reduction robot(FRR)is critical for ensuring the safety of surgery.Improving the repositioning accuracy of a FRR,reducing the error,and realizing a safer and more stable folding motion is cr...The accuracy of a fracture reduction robot(FRR)is critical for ensuring the safety of surgery.Improving the repositioning accuracy of a FRR,reducing the error,and realizing a safer and more stable folding motion is critical.To achieve this,a sparrow search algorithm(SSA)based on the Levy flight operator was proposed in this study for self-tuning the robot controller parameters.An inverse kinematic analysis of the FRR was also performed.The robot dynamics model was established using Simulink,and the inverse dynamics controller for the fracture reduction mechanism was designed using the computed torque control method.Both simulation and physical experiments were also performed.The actual motion trajectory of the actuator drive rod and its error with a desired trajectory was obtained through simulation.An optimized Levy-sparrow search algorithm(Levy-SSA)crack reduction robot controller demonstrated an overall reduction of two orders of magnitude in the reduction error,with an average error reduction of 98.74%compared with the traditional unoptimized controller.The Levy-SSA increased the convergence of the crack reduction robot control system to the optimal solution,improved the accuracy of the motion trajectory,and exhibited important implications for robot controller optimization.展开更多
基金supported by the following grants:Key Project of National Natural Science Foundation of China(Grant No.52032004)National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.51625201)+4 种基金National Natural Science Funds of China(Grant No.52102039)China Postdoctoral Science Foundation(Grant No.2021M700036)The Open Fund of State Key Laboratory of Advanced Welding and Joining(Grant No.AWJ-22Z04)National Defense Supporting Scientific Research Projects(186)Keypoint Research and Invention Program of Heilongjiang Province(GA21D001).
文摘With the development of optical technologies,transparent materials that provide protection from light have received considerable attention from scholars.As important channels for external light,windows play a vital role in the regulation of light in buildings,vehicles,and aircrafts.There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation.In this context,liquid crystals(LCs),owing to their rich responsiveness and unique optical properties,have been considered among the best candidates for advanced light protection materials.In this review,we provide an overview of advances in research on LC-based methods for protection against light.First,we introduce the characteristics of different light sources and their protection requirements.Second,we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection.In addition,we discuss current light protection strategies based on liquid crystal materials for different applications.Finally,we discuss the problems and shortcomings of current strategies.We propose several suggestions for the development of liquid crystal materials in the field of light protection.
基金the financial supports from the National Key Research and Development Program of China(Grant No.2023YFB3811600)the National Science Fund for Distinguished Young Scholars(Grant No.51625201)+6 种基金State Key Program of National Natural Science of China(Grant No.52032004)National Youth Science Funds of China(Grant No.52102039)Key Research and Development Program of Heilongjiang Province(Grant No.GA21D001,2022ZX06C05)the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2022011)the Major Program of Harbin Institute of Technology(Grant NO.2023FRFK01002)the Fundamental Research Funds for the Central Universities(2022FRFK060026)the National Youth Science Funds of China(Grant No.52302172).
文摘A novel multispectral smart window has been proposed,which features dynamic modulation of light transmittance and effective shielding against electromagnetic microwave radiation.This design integrates liquid crystal dynamic scattering and dye doping techniques,enabling the dual regulation of transmittance and scattering within a singlelayer smart window.Additionally,the precise control of conductive film thickness ensures the attainment of robust microwave signal shielding.We present a theoretical model for ion movement in the presence of an alternating electric field,along with a novel approach to manipulate negative dielectric constant.The proposed model successfully enables a rapid transition between light transparent,absorbing and haze states,with an optimum drive frequency adjustable to approximately 300 Hz.Furthermore,the resistive design of the conductive layer effectively mitigates microwave radiation within the 2−18 GHz range.These findings offer an innovative perspective for future advancements in environmental construction.
基金Key Project of National Natural Science Foundation of China(52032004)National Natural Science Foundation for Distinguished Young Scholars of China(51625201)Shanghai Pujiang Program(20PJ1411400)。
文摘Both absorption and diffuse reflection can effectively suppress microwave backward reflection.However,the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working of the two principles.With aid of the wideband characteristic of bilateral complementary structure,we propose a strategy to design wideband absorptive elements with large reflection phase differences.For proof of concept,the proposed elements are arranged in a rectangular grid by optimizing scattering field distribution.The proposed diffusion metabsorber achieves over 20-dB scattering field reduction in the range of 8.5–20.3 GHz with good polarization stability and high angular insensitivity of up to±40°,which has been verified by real experiments.Furthermore,the proposed design strategy exhibits the potential to further reduce electromagnetic wave reflection,and the optical transparent characteristic is promising for window applications.
基金Open Fund of Key Laboratory(JZX7Y201911SY008601)Key Project of National Natural Science Foundation of China(52032004)National Natural Science Foundation for Distinguished Young Scholars of China(51625201)。
文摘In this paper,a 3D meta-atom-based structure is constructed for the multifunctional compatible design of visible,infrared,and microwave.To achieve high performance,a novel dispersion tailoring strategy is proposed.Through the incorporation of multiple controllable losses within the 3D meta-atom,the dispersion characteristics are tailored to the desired target region.The effectiveness of the strategy is verified with an error rate of less than5%.A proof-of-concept prototype is designed and fabricated,exhibiting high visible transparency,low infrared emission of 0.28,and microwave ultra-broadband absorption with a fractional bandwidth of 150%under 2.7 to18.7 GHz.This work contributes a novel design strategy for the development of high-performance multispectral stealth materials with wide applications.
基金supported by the Natural Science Foundation of Guangdong Province(2022A1515010487)Shenzhen Science and Technology Innovation Program(JCYJ20210324103800001)Shenzhen Science and Technology Innovation Program(JCYJ20220530112609022).
文摘The accuracy of a fracture reduction robot(FRR)is critical for ensuring the safety of surgery.Improving the repositioning accuracy of a FRR,reducing the error,and realizing a safer and more stable folding motion is critical.To achieve this,a sparrow search algorithm(SSA)based on the Levy flight operator was proposed in this study for self-tuning the robot controller parameters.An inverse kinematic analysis of the FRR was also performed.The robot dynamics model was established using Simulink,and the inverse dynamics controller for the fracture reduction mechanism was designed using the computed torque control method.Both simulation and physical experiments were also performed.The actual motion trajectory of the actuator drive rod and its error with a desired trajectory was obtained through simulation.An optimized Levy-sparrow search algorithm(Levy-SSA)crack reduction robot controller demonstrated an overall reduction of two orders of magnitude in the reduction error,with an average error reduction of 98.74%compared with the traditional unoptimized controller.The Levy-SSA increased the convergence of the crack reduction robot control system to the optimal solution,improved the accuracy of the motion trajectory,and exhibited important implications for robot controller optimization.
