With the development of human spaceflight,the impact of the microgravity environment in space stations on the work and life of astronauts has received increasing attention.For astronauts,establishing stable and switch...With the development of human spaceflight,the impact of the microgravity environment in space stations on the work and life of astronauts has received increasing attention.For astronauts,establishing stable and switchable attachments to multiple surfaces in an orbiting space station is important and yet a great challenge.Here,inspired by the variable stiffness structures of biological adhesion organs with different functional directions,a multi-modulus adhesive unit is designed.The low-modulus adhesive layer provides good adaptability by mimicking the soft bottom of the rock-climbing loach suction cups and the setae on the gecko’s toes;the high-modulus flat substrate provides good stiffness to suppress deformation;the elasticity adaption layer reduces preload required for attachment to uneven surfaces like gecko muscular tissues,and the detachment switch made from nylon rope allows switching the adhesion force by adjusting the angle of force.Experiments in simulated microgravity environments demonstrate the ability of the adhesive shoes to rapidly generate strong and switchable adhesion and friction on rough surfaces,and tests in China's space station show that adhesive shoes based on multi-mechanism adhesion are a viable option for lower limb muscle exercising.展开更多
Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid ...Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.展开更多
Complex plasma fluctuation processes have been extensively studied in many aspects,especially lattice waves in strongly coupled plasma crystals,which are of great significance for understanding fundamental physical ph...Complex plasma fluctuation processes have been extensively studied in many aspects,especially lattice waves in strongly coupled plasma crystals,which are of great significance for understanding fundamental physical phenomena.A challenge of experimental investigations in two-dimensional strongly coupled complex plasma crystals is to keep the main body and foreign particles of different masses on the same horizontal plane.To solve the problem,we have proposed a potential well formed by two negatively biased grids to bind the negatively charged particles in a two-dimensional(2D)plane,thus achieving a 2D plasma crystal in the microgravity environment.The study of such phenomena in complex plasma crystals under microgravity environment then becomes possible.In this paper,we focus on the continuum spectrum,including both phonon and optic branches of the impurity mode in a 2D system in microgravity environments.The results show the dispersion relation of the longitudinal and transverse impurity oscillation modes and their properties.Considering the macroscopic visibility of complex mesoscopic particle lattices,theoretical and experimental studies on this kind of complex plasma systems will help us further understand the physical nature of a wide range of condensed matters.展开更多
基金supported by the National Natural Science Foundation of China(nos.52075249 and 62233008)the Space Medical Experiment Project of China Manned Space Program(no.HYZHXM01009).
文摘With the development of human spaceflight,the impact of the microgravity environment in space stations on the work and life of astronauts has received increasing attention.For astronauts,establishing stable and switchable attachments to multiple surfaces in an orbiting space station is important and yet a great challenge.Here,inspired by the variable stiffness structures of biological adhesion organs with different functional directions,a multi-modulus adhesive unit is designed.The low-modulus adhesive layer provides good adaptability by mimicking the soft bottom of the rock-climbing loach suction cups and the setae on the gecko’s toes;the high-modulus flat substrate provides good stiffness to suppress deformation;the elasticity adaption layer reduces preload required for attachment to uneven surfaces like gecko muscular tissues,and the detachment switch made from nylon rope allows switching the adhesion force by adjusting the angle of force.Experiments in simulated microgravity environments demonstrate the ability of the adhesive shoes to rapidly generate strong and switchable adhesion and friction on rough surfaces,and tests in China's space station show that adhesive shoes based on multi-mechanism adhesion are a viable option for lower limb muscle exercising.
基金supported by the Natural Science Foundation of China(No.51706190)the State Scholarship Fund of China Scholarship Council。
文摘Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.
基金supported by“Undergraduate Innovation and Entrepreneurship Training Program”at Harbin Institute of Technology。
文摘Complex plasma fluctuation processes have been extensively studied in many aspects,especially lattice waves in strongly coupled plasma crystals,which are of great significance for understanding fundamental physical phenomena.A challenge of experimental investigations in two-dimensional strongly coupled complex plasma crystals is to keep the main body and foreign particles of different masses on the same horizontal plane.To solve the problem,we have proposed a potential well formed by two negatively biased grids to bind the negatively charged particles in a two-dimensional(2D)plane,thus achieving a 2D plasma crystal in the microgravity environment.The study of such phenomena in complex plasma crystals under microgravity environment then becomes possible.In this paper,we focus on the continuum spectrum,including both phonon and optic branches of the impurity mode in a 2D system in microgravity environments.The results show the dispersion relation of the longitudinal and transverse impurity oscillation modes and their properties.Considering the macroscopic visibility of complex mesoscopic particle lattices,theoretical and experimental studies on this kind of complex plasma systems will help us further understand the physical nature of a wide range of condensed matters.
