Using data from the James Webb Space Telescope,which was launched by NASA in 2021,scientists determined that an exoplanet(a planet outside our solar system)has the conditions needed to support life.The planet,called L...Using data from the James Webb Space Telescope,which was launched by NASA in 2021,scientists determined that an exoplanet(a planet outside our solar system)has the conditions needed to support life.The planet,called LHS 1140 b,is known as an“eyeball”planet because it resembles a giant human eye.It is about 50 light-years from Earth.展开更多
Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched.Two Mars exploration missions are designed to investigate geological s...Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched.Two Mars exploration missions are designed to investigate geological structure,the material on Martian surface,and retrieve returned samples.The asteroids and main belt comet exploration is expected to explore two objects within 10 years.The small-body mission will aim to land on the asteroid and get samples return to Earth.The basic physical characteristics of the two objects will be obtained through the mission.The exploration of Jupiter system will characterize the environment of Jupiter and the four largest Moons and understand the atmosphere of Jupiter.In addition,we further introduce two space-based exoplanet survey by 2030,Miyin Program and Closeby Habitable Exoplanet Survey(CHES Mission).Miyin program aims to detect habitable exoplanets using interferometry,while CHES mission expects to discover habitable exoplanets orbiting FGK stars within 10 pc through astrometry.The above-mentioned missions are positively to achieve breakthroughs in the field of planetary science.展开更多
A finite element model of one-arm planet carrier was built, and influence of structural parameters on strength and stiffness for one-arm planet carrier was analyzed. The stress and deformation of the round structure a...A finite element model of one-arm planet carrier was built, and influence of structural parameters on strength and stiffness for one-arm planet carrier was analyzed. The stress and deformation of the round structure and the triangle structure for one-arm planet carrier were analyzed and compared. The finite element model of the same specifications arms planet carrier was established, and influence of the connecting slab thickness and input side plate thickness on strength and stiffness for arms planet carrier was analyzed. Strength, stiffness and mass for one-arm and arms planet carrier in the same specifications were analyzed and compared.展开更多
Considering the effect of planet's number on the dynamic characteristics of the planetary gear system, a translationtorsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the an...Considering the effect of planet's number on the dynamic characteristics of the planetary gear system, a translationtorsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the analysis of numerical solution, the results show that 1) When the planet's number is more than 3, the order of the natural frequency will become the same; 2) When the planet's number increases, the natural frequencies of planet mode remain invariant, but when it comes to rotational mode and translational mode, the higher order natural frequencies increase and the lower order natural frequencies decrease; 3) The planet's number has a great impact on the higher order natural frequencies and a little impact on the lower order natural frequencies; and 4) To avoid the resonance, we can appropriately increase or decrease the number of the planet.展开更多
Deep dielectric charging/discharging,caused by high energy electrons,is an important consideration in electronic devices used in space environments because it can lead to spacecraft anomalies and failures.The Jovian p...Deep dielectric charging/discharging,caused by high energy electrons,is an important consideration in electronic devices used in space environments because it can lead to spacecraft anomalies and failures.The Jovian planets,including Saturn,Uranus,Neptune and Jupiter’s moons,are believed to have robust electron radiation belts at relativistic energies.In particular,Jupiter is thought to have caused at least 42 internal electrostatic discharge events during the Voyager 1 flyby.With the development of deep space exploration,there is an increased focus on the deep dielectric charging effects in the orbits of Jovian planets.In this paper,GEANT4,a Monte Carlo toolkit,and radiation-induced conductivity(RIC)are used to calculate deep dielectric charging effects for Jovian planets.The results are compared with the criteria for preventing deep dielectric charging effects in Earth orbit.The findings show that effective criteria used in Earth orbit are not always appropriate for preventing deep dielectric charging effects in Jovian orbits.Generally,Io,Europa,Saturn(R_S=6),Uranus(L=4.73)and Ganymede missions should have a thicker shield or higher dielectric conductivity,while Neptune(L=7.4)and Callisto missions can have a thinner shield thickness or a lower dielectric conductivity.Moreover,dielectrics grounded with double metal layers and thinner dielectrics can also decrease the likelihood of discharges.展开更多
Small planetary bodies usually have irregular shapes.If they are large enough to be heated to a partial melting status,the deforming force of gravity could overcome the internal forces and make the shape transfigure f...Small planetary bodies usually have irregular shapes.If they are large enough to be heated to a partial melting status,the deforming force of gravity could overcome the internal forces and make the shape transfigure from potato-like to spherical.We have developed a model to calculate the thermal history of a planetoid and apply the model to asteroids,since ample evidence has shown that many asteroids could have undergone differentiation.After revealing the relation between the shape and the ratio of the melt part,we also examine the surface roughness of these asteroids and suggest that 280km would be a critical radius for an asteroid to develop a virtually globular contour.展开更多
WE ALL HAVE A BIG RESPONSIBILITY: TO DESIGN EXCELLENT FASHION AND CONTRIBUTE TO SAVING OUR EARTH. THE DIALOGUE THAT SPRINGS FROM EVENTS LIKE THE PRESENTATION OF THE TRENDS IS AN IMPORTANT TOOL FOR THE ENTIRE FASHION I...WE ALL HAVE A BIG RESPONSIBILITY: TO DESIGN EXCELLENT FASHION AND CONTRIBUTE TO SAVING OUR EARTH. THE DIALOGUE THAT SPRINGS FROM EVENTS LIKE THE PRESENTATION OF THE TRENDS IS AN IMPORTANT TOOL FOR THE ENTIRE FASHION INDUSTRY On October 25,2017,the route to the 26th edition of Milano展开更多
https://www.sciencedirect.com/journal/energy-and-buildings/vol/316/suppl/C Volume 316,1 August 2024[OA](1) Energy demand parametric analysis and geothermal heat exchanger design applied to a nearly zero energy PV buil...https://www.sciencedirect.com/journal/energy-and-buildings/vol/316/suppl/C Volume 316,1 August 2024[OA](1) Energy demand parametric analysis and geothermal heat exchanger design applied to a nearly zero energy PV building in northern Italy by Antonella Priarone,Marco Fossa,Stefano Morchio,et al,Article 114292Abstract:Nearly-Zero-Energy and Zero-Emission Buildings are one fundamental part of the world strategies addressed at mitigating the global warming trend and coping with the goal of setting1.5℃the planet temperature increase with respect to the preindustrial conditions.The present paper refers to a specific case study,the Smart Energy Building (SEB) located in the Savona Campus of the University of Genoa.展开更多
Researchers at Lund University in Sweden have now succeeded in making new viscose-from wornout cotton sheets.Old textiles around the world end up at the rubbish tip and are often burned.In Sweden,they are generally bu...Researchers at Lund University in Sweden have now succeeded in making new viscose-from wornout cotton sheets.Old textiles around the world end up at the rubbish tip and are often burned.In Sweden,they are generally burned to produce district heating.Extensive development work is being conducted to give old clothes and textiles a worthier end.The planet really needs recycled textiles,as it takes a lot of energy,water and land to cultivate cotton and other plant sources for textiles.However,there are many challenges.展开更多
Astronomy is the science of stars,planets and space.Someone who studies astronomy is an astronomer.Yes!Now is a very exciting time for astronomers.In early 2017,seven planets were discovered around a star called TRAPP...Astronomy is the science of stars,planets and space.Someone who studies astronomy is an astronomer.Yes!Now is a very exciting time for astronomers.In early 2017,seven planets were discovered around a star called TRAPPIST-1.These planets are a similar size to our planet,Earth,and we believe that at least three of these planets possibly have water.展开更多
文摘Using data from the James Webb Space Telescope,which was launched by NASA in 2021,scientists determined that an exoplanet(a planet outside our solar system)has the conditions needed to support life.The planet,called LHS 1140 b,is known as an“eyeball”planet because it resembles a giant human eye.It is about 50 light-years from Earth.
基金Supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences(XDB41000000)the National Natural Science Foundation of China(11773081,11573073)CAS Interdisciplinary Innovation Team,Foundation of Minor Planets of the Purple Mountain Observatory and Youth Innovation Promotion Association。
文摘Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched.Two Mars exploration missions are designed to investigate geological structure,the material on Martian surface,and retrieve returned samples.The asteroids and main belt comet exploration is expected to explore two objects within 10 years.The small-body mission will aim to land on the asteroid and get samples return to Earth.The basic physical characteristics of the two objects will be obtained through the mission.The exploration of Jupiter system will characterize the environment of Jupiter and the four largest Moons and understand the atmosphere of Jupiter.In addition,we further introduce two space-based exoplanet survey by 2030,Miyin Program and Closeby Habitable Exoplanet Survey(CHES Mission).Miyin program aims to detect habitable exoplanets using interferometry,while CHES mission expects to discover habitable exoplanets orbiting FGK stars within 10 pc through astrometry.The above-mentioned missions are positively to achieve breakthroughs in the field of planetary science.
基金Funded by National Science and Technology Support Program(Grant No.2013BAF01B05)Zhengzhou Science and Technology Project(Grant No.121PZDGG255)
文摘A finite element model of one-arm planet carrier was built, and influence of structural parameters on strength and stiffness for one-arm planet carrier was analyzed. The stress and deformation of the round structure and the triangle structure for one-arm planet carrier were analyzed and compared. The finite element model of the same specifications arms planet carrier was established, and influence of the connecting slab thickness and input side plate thickness on strength and stiffness for arms planet carrier was analyzed. Strength, stiffness and mass for one-arm and arms planet carrier in the same specifications were analyzed and compared.
基金Funded by the Key Research and Development Project in Henan Province(No.142102210067)
文摘Considering the effect of planet's number on the dynamic characteristics of the planetary gear system, a translationtorsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the analysis of numerical solution, the results show that 1) When the planet's number is more than 3, the order of the natural frequency will become the same; 2) When the planet's number increases, the natural frequencies of planet mode remain invariant, but when it comes to rotational mode and translational mode, the higher order natural frequencies increase and the lower order natural frequencies decrease; 3) The planet's number has a great impact on the higher order natural frequencies and a little impact on the lower order natural frequencies; and 4) To avoid the resonance, we can appropriately increase or decrease the number of the planet.
基金supported by Beijing Municipal Natural Science Foundation-Quantitative Research on Mitigating Deep Dielectric Charging Effects in Jupiter orbits(No.3184048)National Key Scientific Instrument and Equipment Development Projects,China(No.2012YQ03014207)。
文摘Deep dielectric charging/discharging,caused by high energy electrons,is an important consideration in electronic devices used in space environments because it can lead to spacecraft anomalies and failures.The Jovian planets,including Saturn,Uranus,Neptune and Jupiter’s moons,are believed to have robust electron radiation belts at relativistic energies.In particular,Jupiter is thought to have caused at least 42 internal electrostatic discharge events during the Voyager 1 flyby.With the development of deep space exploration,there is an increased focus on the deep dielectric charging effects in the orbits of Jovian planets.In this paper,GEANT4,a Monte Carlo toolkit,and radiation-induced conductivity(RIC)are used to calculate deep dielectric charging effects for Jovian planets.The results are compared with the criteria for preventing deep dielectric charging effects in Earth orbit.The findings show that effective criteria used in Earth orbit are not always appropriate for preventing deep dielectric charging effects in Jovian orbits.Generally,Io,Europa,Saturn(R_S=6),Uranus(L=4.73)and Ganymede missions should have a thicker shield or higher dielectric conductivity,while Neptune(L=7.4)and Callisto missions can have a thinner shield thickness or a lower dielectric conductivity.Moreover,dielectrics grounded with double metal layers and thinner dielectrics can also decrease the likelihood of discharges.
基金Supported by the National Natural Science Foundation of China under Grant Nos 41074118 and 40890163the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant Nos KJCX2-YW-T13-3 and KZCX2-EW-QN501.
文摘Small planetary bodies usually have irregular shapes.If they are large enough to be heated to a partial melting status,the deforming force of gravity could overcome the internal forces and make the shape transfigure from potato-like to spherical.We have developed a model to calculate the thermal history of a planetoid and apply the model to asteroids,since ample evidence has shown that many asteroids could have undergone differentiation.After revealing the relation between the shape and the ratio of the melt part,we also examine the surface roughness of these asteroids and suggest that 280km would be a critical radius for an asteroid to develop a virtually globular contour.
文摘WE ALL HAVE A BIG RESPONSIBILITY: TO DESIGN EXCELLENT FASHION AND CONTRIBUTE TO SAVING OUR EARTH. THE DIALOGUE THAT SPRINGS FROM EVENTS LIKE THE PRESENTATION OF THE TRENDS IS AN IMPORTANT TOOL FOR THE ENTIRE FASHION INDUSTRY On October 25,2017,the route to the 26th edition of Milano
文摘https://www.sciencedirect.com/journal/energy-and-buildings/vol/316/suppl/C Volume 316,1 August 2024[OA](1) Energy demand parametric analysis and geothermal heat exchanger design applied to a nearly zero energy PV building in northern Italy by Antonella Priarone,Marco Fossa,Stefano Morchio,et al,Article 114292Abstract:Nearly-Zero-Energy and Zero-Emission Buildings are one fundamental part of the world strategies addressed at mitigating the global warming trend and coping with the goal of setting1.5℃the planet temperature increase with respect to the preindustrial conditions.The present paper refers to a specific case study,the Smart Energy Building (SEB) located in the Savona Campus of the University of Genoa.
文摘Researchers at Lund University in Sweden have now succeeded in making new viscose-from wornout cotton sheets.Old textiles around the world end up at the rubbish tip and are often burned.In Sweden,they are generally burned to produce district heating.Extensive development work is being conducted to give old clothes and textiles a worthier end.The planet really needs recycled textiles,as it takes a lot of energy,water and land to cultivate cotton and other plant sources for textiles.However,there are many challenges.
文摘Astronomy is the science of stars,planets and space.Someone who studies astronomy is an astronomer.Yes!Now is a very exciting time for astronomers.In early 2017,seven planets were discovered around a star called TRAPPIST-1.These planets are a similar size to our planet,Earth,and we believe that at least three of these planets possibly have water.
