The UV-2600 ultraviolet(UV)spectrophotometer and the UV sunscreen index analyzer SolarLight Model 601 were used to test the UV absorption capacity and the UV damage alleviating effect of commonly used raw materials,an...The UV-2600 ultraviolet(UV)spectrophotometer and the UV sunscreen index analyzer SolarLight Model 601 were used to test the UV absorption capacity and the UV damage alleviating effect of commonly used raw materials,and the Hen’s Egg Test-Chorioallantoic Membrane were also processed to assess the mildness.As a result,bisabolol,pongamia pinnata seed extract,pterocarpus marsupium bark extract and other materials were screened as the effective and gentle sunscreen synergistic ingredients.展开更多
Stringent attitude determination accuracy is required for the development of the advanced space technologies and thus the accuracy improvement of digital sun sensors is necessary.In this paper,we presented a proposal ...Stringent attitude determination accuracy is required for the development of the advanced space technologies and thus the accuracy improvement of digital sun sensors is necessary.In this paper,we presented a proposal for measurement error analysis of a digital sun sensor.A system modeling including three different error sources was built and employed for system error analysis.Numerical simulations were also conducted to study the measurement error introduced by different sources of error.Based on our model and study,the system errors from different error sources are coupled and the system calibration should be elaborately designed to realize a digital sun sensor with extra-high accuracy.展开更多
Correlations between the rotations of the terrestrial planets in our solar system and the magnetic field of the Sun have been previously noted. These correlations account for the opposite rotation of Venus as a result...Correlations between the rotations of the terrestrial planets in our solar system and the magnetic field of the Sun have been previously noted. These correlations account for the opposite rotation of Venus as a result of the magnetic field of the Sun being dragged across the conducting core of Venus. Currently, the Sun’s magnetic field is not sufficiently strong to account for the proposed correlations. But recently meteorite paleomagnetism measurements have indicated that during the Sun’s formation the magnetic field of the Sun was of sufficient strength to have resulted in the observed correlations. Also, dating back to the Sun’s formation are measurements showing that the Sun’s core rotates four times faster than the Sun’s surface. Both the counter rotation of Venus and the initial period of strong Sun magnetic fields are believed to be relics of the time period when the Sun’s core to surface differential rotation was established. As a part of these correlations, it was hypothesized that for a terrestrial planet to exhibit a magnetosphere, the average density must be ≥5350 ± 50 kg/m<sup>3</sup>. On this basis, only the Earth and Mercury would have formed initial magnetospheres, while Venus, Mars, and the “Moon” would not have developed magnetospheres. For such correlations to still be present today requires our Sun to have been formed as a sole star and with what might be termed a friendly Jupiter. Otherwise, the observed correlations would have been disrupted over time.展开更多
Energy crisis promotes the development of renewable energy, especially the solar energy. Sun tracking system proposed in this paper is such a device for efficiency improvement. This closed loop tracking system with tw...Energy crisis promotes the development of renewable energy, especially the solar energy. Sun tracking system proposed in this paper is such a device for efficiency improvement. This closed loop tracking system with two axis sun tracking method is controlled by a programmable logic controller (PLC) and is used for a large dish solar collector. A combination tracking mode combined active and passive tracking methods used in the design make the tracker efficient whatever the circumstances. Two stepper motors and two reduction boxes move the device towards the sun with chain transmission. Besides sun tracking, the system also has functions of overheat monitoring, wind speed monitoring and measurement of illumination.展开更多
The 40-acre factory compound, huge storehouses, modern production and distribution lines, and hard-working staff members, all these impressed me so much when I took an interview event with Sun Yingbin, logistics manag...The 40-acre factory compound, huge storehouses, modern production and distribution lines, and hard-working staff members, all these impressed me so much when I took an interview event with Sun Yingbin, logistics manager of century-old tea brand Wuyutai, in its logistics and distribution center in the suburb of Beijing.展开更多
Asteroid exploration trajectories which start from a lunar orbit are investigated in this work.It is assumed that the probe departs from lunar orbit and returns to the vicinity of Earth,then escapes from the Earth by ...Asteroid exploration trajectories which start from a lunar orbit are investigated in this work.It is assumed that the probe departs from lunar orbit and returns to the vicinity of Earth,then escapes from the Earth by performing a perigee maneuver.A low-energy transfer in Sun-EarthMoon system is adopted.First,the feasible region of lowenergy transfer from lunar orbit to perigee within 5 000 km height above the Earth surface in Sun-Earth-Moon system is calculated and analyzed.Three transfer types are found,i.e.,large maneuver and fast transfers,small maneuver and fast transfers,and disordered and slow transfers.Most of feasibility trajectories belong to the first two types.Then,the lowenergy trajectory leg from lunar orbit to perigee and a heliocentric trajectory leg from perigee to asteroid are patched by a perigee maneuver.The optimal full-transfer trajectory is obtained by exploiting the differential evolution algorithm.Finally,taking 4179 Toutatis asteroid as the target,some low-energy transfer trajectories are obtained and analyzed.展开更多
The Measures on Aid and Management for Urban Vagrants and Beggars, issued by the State Council in mid-July, took effect on August 1. It marks a further improvement of China’s mechanism to aid urban vagrants and begga...The Measures on Aid and Management for Urban Vagrants and Beggars, issued by the State Council in mid-July, took effect on August 1. It marks a further improvement of China’s mechanism to aid urban vagrants and beggars. The new regulation has been enacted to replace the two-decade-old Measures for the Internment and Deportation of Urban Vagrants and Beggars. This policy reform has stemmed from the astounding case of Sun Zhigang, a young man that was brutally beaten to death while in custody at the Guangzhou Detention Center.展开更多
This study analyzes the evolution and dynamics of intensity oscillations in coronal sunspots and their surroundings using multi-wavelength image data from the Atmospheric Imaging Assembly(AIA)and Helioseismic and Magn...This study analyzes the evolution and dynamics of intensity oscillations in coronal sunspots and their surroundings using multi-wavelength image data from the Atmospheric Imaging Assembly(AIA)and Helioseismic and Magnetic Imager(HMI)on board the Solar Dynamics Observatory(SDO).Intensity time series were extracted and analyzed from consecutive macropixels along thin coronal loop paths originating in a quiet sunspot.Fourier and wavelet analyses of corrected intensity time series reveal dominant 3 and 5 minute oscillations.Signals were filtered using the Fourier and inverse transforms to isolate narrow bands around the dominant oscillation periods.Diagrams and time-distance maps of intensity time series were plotted for Fourierfiltered AIA 131A,171A,193A,and 211A channels,along with SDO/HMI magnetograms and dopplergrams at 6173A.The plots clearly show propagating oscillations with amplitude modulation(AM)across all macropixels along selected coronal paths in nearly all AIA and HMI channels.The phase speeds of the filtered oscillations,measured via slope calculations in time-distance maps,indicate that the intensity disturbances are slow magneto-acoustic waves.These results suggest that AM likely arises from the superposition of counterpropagating waves with slightly different frequencies(beta-like phenomena)due to Doppler shifts from background plasma flow along loop paths.Validating this hypothesis could establish AM's significance in solar coronal seismology for determining background plasma flow speed,the source of long-period oscillations,and coronal plasma heating mechanisms.展开更多
We analyze the periodic orbits, quasi periodic orbits and chaotic orbits in the photo gravitational Sun-Saturn system incorporating actual oblateness of Saturn in the planar circular restricted three body problem. In ...We analyze the periodic orbits, quasi periodic orbits and chaotic orbits in the photo gravitational Sun-Saturn system incorporating actual oblateness of Saturn in the planar circular restricted three body problem. In this paper, we study the effect of solar radiation pressure on the location of Sun centered and Saturn centered orbits, its diameter, semi major axis and eccentricity by taking different values of solar radiation pressure q and different values of Jacobi constant “C”, and by considering actual oblateness of Saturn using Poincare surface of section (PSS) method. It is ob-served that by the introduction of perturbing force due to solar radiation pressure admissible range of Jacobi constant C decreases, it is also observed that as value of C decreases the number of islands decreases and as a result the number of periodic and quasi periodic orbits decreases.Fur-ther, the periodic orbits around Saturn and Sun moves towards Sun by decreasing perturbation due to solar radiation pressure q for a specific choice of Jacobi constant C. It is also observed that due to solar radiation pressure, semi major axis and eccentricity of Sun centered periodic orbit reduces, whereas, due to solar radiation pressure uniform change in semi major axis and eccen-tricity of Saturn centered periodic orbits is observed.展开更多
文摘The UV-2600 ultraviolet(UV)spectrophotometer and the UV sunscreen index analyzer SolarLight Model 601 were used to test the UV absorption capacity and the UV damage alleviating effect of commonly used raw materials,and the Hen’s Egg Test-Chorioallantoic Membrane were also processed to assess the mildness.As a result,bisabolol,pongamia pinnata seed extract,pterocarpus marsupium bark extract and other materials were screened as the effective and gentle sunscreen synergistic ingredients.
基金the financial support by the National 863 Project ( No. 2012AA121503 )the China NSF projects ( No. 61377012 , No. 61505094 )China Postdoctoral Science Foundation funded project ( 2015M571034 )
文摘Stringent attitude determination accuracy is required for the development of the advanced space technologies and thus the accuracy improvement of digital sun sensors is necessary.In this paper,we presented a proposal for measurement error analysis of a digital sun sensor.A system modeling including three different error sources was built and employed for system error analysis.Numerical simulations were also conducted to study the measurement error introduced by different sources of error.Based on our model and study,the system errors from different error sources are coupled and the system calibration should be elaborately designed to realize a digital sun sensor with extra-high accuracy.
文摘Correlations between the rotations of the terrestrial planets in our solar system and the magnetic field of the Sun have been previously noted. These correlations account for the opposite rotation of Venus as a result of the magnetic field of the Sun being dragged across the conducting core of Venus. Currently, the Sun’s magnetic field is not sufficiently strong to account for the proposed correlations. But recently meteorite paleomagnetism measurements have indicated that during the Sun’s formation the magnetic field of the Sun was of sufficient strength to have resulted in the observed correlations. Also, dating back to the Sun’s formation are measurements showing that the Sun’s core rotates four times faster than the Sun’s surface. Both the counter rotation of Venus and the initial period of strong Sun magnetic fields are believed to be relics of the time period when the Sun’s core to surface differential rotation was established. As a part of these correlations, it was hypothesized that for a terrestrial planet to exhibit a magnetosphere, the average density must be ≥5350 ± 50 kg/m<sup>3</sup>. On this basis, only the Earth and Mercury would have formed initial magnetospheres, while Venus, Mars, and the “Moon” would not have developed magnetospheres. For such correlations to still be present today requires our Sun to have been formed as a sole star and with what might be termed a friendly Jupiter. Otherwise, the observed correlations would have been disrupted over time.
文摘Energy crisis promotes the development of renewable energy, especially the solar energy. Sun tracking system proposed in this paper is such a device for efficiency improvement. This closed loop tracking system with two axis sun tracking method is controlled by a programmable logic controller (PLC) and is used for a large dish solar collector. A combination tracking mode combined active and passive tracking methods used in the design make the tracker efficient whatever the circumstances. Two stepper motors and two reduction boxes move the device towards the sun with chain transmission. Besides sun tracking, the system also has functions of overheat monitoring, wind speed monitoring and measurement of illumination.
文摘The 40-acre factory compound, huge storehouses, modern production and distribution lines, and hard-working staff members, all these impressed me so much when I took an interview event with Sun Yingbin, logistics manager of century-old tea brand Wuyutai, in its logistics and distribution center in the suburb of Beijing.
基金supported by the National Basic Research Programof China(973 Program)(2012CB720000)the National Natural Science Foundation of China(11102020)+1 种基金Program for New Century Excellent Talents in UniversityBeijing Higher Education Young Elite Teacher Project and China Scholarship Council
文摘Asteroid exploration trajectories which start from a lunar orbit are investigated in this work.It is assumed that the probe departs from lunar orbit and returns to the vicinity of Earth,then escapes from the Earth by performing a perigee maneuver.A low-energy transfer in Sun-EarthMoon system is adopted.First,the feasible region of lowenergy transfer from lunar orbit to perigee within 5 000 km height above the Earth surface in Sun-Earth-Moon system is calculated and analyzed.Three transfer types are found,i.e.,large maneuver and fast transfers,small maneuver and fast transfers,and disordered and slow transfers.Most of feasibility trajectories belong to the first two types.Then,the lowenergy trajectory leg from lunar orbit to perigee and a heliocentric trajectory leg from perigee to asteroid are patched by a perigee maneuver.The optimal full-transfer trajectory is obtained by exploiting the differential evolution algorithm.Finally,taking 4179 Toutatis asteroid as the target,some low-energy transfer trajectories are obtained and analyzed.
文摘The Measures on Aid and Management for Urban Vagrants and Beggars, issued by the State Council in mid-July, took effect on August 1. It marks a further improvement of China’s mechanism to aid urban vagrants and beggars. The new regulation has been enacted to replace the two-decade-old Measures for the Internment and Deportation of Urban Vagrants and Beggars. This policy reform has stemmed from the astounding case of Sun Zhigang, a young man that was brutally beaten to death while in custody at the Guangzhou Detention Center.
文摘This study analyzes the evolution and dynamics of intensity oscillations in coronal sunspots and their surroundings using multi-wavelength image data from the Atmospheric Imaging Assembly(AIA)and Helioseismic and Magnetic Imager(HMI)on board the Solar Dynamics Observatory(SDO).Intensity time series were extracted and analyzed from consecutive macropixels along thin coronal loop paths originating in a quiet sunspot.Fourier and wavelet analyses of corrected intensity time series reveal dominant 3 and 5 minute oscillations.Signals were filtered using the Fourier and inverse transforms to isolate narrow bands around the dominant oscillation periods.Diagrams and time-distance maps of intensity time series were plotted for Fourierfiltered AIA 131A,171A,193A,and 211A channels,along with SDO/HMI magnetograms and dopplergrams at 6173A.The plots clearly show propagating oscillations with amplitude modulation(AM)across all macropixels along selected coronal paths in nearly all AIA and HMI channels.The phase speeds of the filtered oscillations,measured via slope calculations in time-distance maps,indicate that the intensity disturbances are slow magneto-acoustic waves.These results suggest that AM likely arises from the superposition of counterpropagating waves with slightly different frequencies(beta-like phenomena)due to Doppler shifts from background plasma flow along loop paths.Validating this hypothesis could establish AM's significance in solar coronal seismology for determining background plasma flow speed,the source of long-period oscillations,and coronal plasma heating mechanisms.
文摘We analyze the periodic orbits, quasi periodic orbits and chaotic orbits in the photo gravitational Sun-Saturn system incorporating actual oblateness of Saturn in the planar circular restricted three body problem. In this paper, we study the effect of solar radiation pressure on the location of Sun centered and Saturn centered orbits, its diameter, semi major axis and eccentricity by taking different values of solar radiation pressure q and different values of Jacobi constant “C”, and by considering actual oblateness of Saturn using Poincare surface of section (PSS) method. It is ob-served that by the introduction of perturbing force due to solar radiation pressure admissible range of Jacobi constant C decreases, it is also observed that as value of C decreases the number of islands decreases and as a result the number of periodic and quasi periodic orbits decreases.Fur-ther, the periodic orbits around Saturn and Sun moves towards Sun by decreasing perturbation due to solar radiation pressure q for a specific choice of Jacobi constant C. It is also observed that due to solar radiation pressure, semi major axis and eccentricity of Sun centered periodic orbit reduces, whereas, due to solar radiation pressure uniform change in semi major axis and eccen-tricity of Saturn centered periodic orbits is observed.
