Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-criticaldensity plasmas.It is found theoretically and numerically that the radiation pressure of a circularly po...Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-criticaldensity plasmas.It is found theoretically and numerically that the radiation pressure of a circularly polarized laser pulse first compresses the plasma electrons to form a dense flying mirror with a relativistic high speed.The pulse reflected by the mirror is red-shifted to the mid-infrared range.Full three-dimensional simulations demonstrate that the central wavelength of the mid-infrared pulse is tunable from 3µm to 14µm,and the laser energy conversion efficiency can reach as high as 13%.With a 0.5–10 PW incident laser pulse,the generated mid-infrared pulse reaches a peak power of 10–180 TW,which is interesting for various applications in ultrafast and high-field sciences.展开更多
American Hollywood animated films have conquered the world.In recent years,many successful works have appeared in domestic animated films,bringing new vitality to the Chinese animated film industry.Based on Lacan’s M...American Hollywood animated films have conquered the world.In recent years,many successful works have appeared in domestic animated films,bringing new vitality to the Chinese animated film industry.Based on Lacan’s Mirror Stage Theory,this study attempts to start from the bravery of Judy and Nezha,the protagonists of Zootopia(2016)and Nezha(2019).It analyzes and compares their embodiment,formation,influence and reflection with real society to solve the problems of the two brave characters’formation causes,characteristic differences and social influences,including racial discrimination,individualism in American society and family problems in Chinese society.This study sheds light on the transmission of intercultural values in animated films.展开更多
A mirror mode wave is a fundamental magnetic structure in the planetary space environment that is persistently compressed by solar wind,especially in the magnetosheath.Mirror modes have been widely identified in the m...A mirror mode wave is a fundamental magnetic structure in the planetary space environment that is persistently compressed by solar wind,especially in the magnetosheath.Mirror modes have been widely identified in the magnetosheaths of the Earth and other planets in the solar system,yet the understanding of mirror mode waves on extraterrestrial planets is not as comprehensive as that on the Earth.Using magnetic field data collected by the Cassini spacecraft,we found peak and dip types according to the magnetic morphology(i.e.,structures with higher or lower magnetic strengths than the background field).Moreover,mirror mode waves and electromagnetic ion cyclotron waves were found one after the other,implying that the two wave modes may evolve into one another in the Kronian magnetosheath.The results indicate that many fundamental plasma processes associated with the mirror mode structure exist in the Kronian magnetosheath.The energy conversion in Saturn’s magnetosheath may provide key insights that will aid in understanding giant planetary magnetospheric processes.展开更多
Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical sur...Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical surfaces,and the incorporation of the deformable mirror.Typically,voice-coil actuators are used,which require additional position sensors,internal control electronics,and cooling systems,leading to a very complex structure.Piezoelectric deformable secondary mirror technologies were proposed to overcome these problems.Recently,a high-order piezoelectric deformable secondary mirror has been developed and installed on the 1.8-m telescope at Lijiang Observatory in China to make it an adaptive telescope.The system consists of a 241-actuator piezoelectric deformable secondary mirror,a 192-sub-aperture Shack-Hartmann wavefront sensor,and a multi-core-based real-time controller.The actuator spacing of the PDSM measures 19.3 mm,equivalent to approximately 12.6 cm when mapped onto the primary mirror,significantly less than the voicecoil-based adaptive telescopes such as LBT,Magellan and VLT.As a result,stellar images with Strehl ratios above 0.49 in the R band have been obtained.To our knowledge,these are the highest R band images captured by an adaptive telescope with deformable secondary mirrors.Here,we report the system description and on-sky performance of this adaptive telescope.展开更多
Since it was first described as a method to treat phantom limb pain, mirror therapy(MT) has been applied in many areas of rehabilitation. Its seminal application with the aim of restoring motor function following stro...Since it was first described as a method to treat phantom limb pain, mirror therapy(MT) has been applied in many areas of rehabilitation. Its seminal application with the aim of restoring motor function following stroke is considered to be that of Altschuler et al.(1999).展开更多
We study the space of stability conditions on K3 surfaces from the perspective of mirror symmetry. This is done in the attractor backgrounds(moduli). We find certain highly non-generic behaviors of marginal stability ...We study the space of stability conditions on K3 surfaces from the perspective of mirror symmetry. This is done in the attractor backgrounds(moduli). We find certain highly non-generic behaviors of marginal stability walls(a key notion in the study of wall crossings)in the space of stability conditions. These correspond via mirror symmetry to some nongeneric behaviors of special Lagrangians in an attractor background. The main results can be understood as a mirror correspondence in a synthesis of the homological mirror conjecture and SYZ mirror conjecture.展开更多
Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems,which probe electron temperature and density during inertial confinement fusion processes.In this study,aperiodic Mo/B_(4)C multi...Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems,which probe electron temperature and density during inertial confinement fusion processes.In this study,aperiodic Mo/B_(4)C multilayer mirrors of varied thick-nesses were investigated for X-ray plasma diagnostics at the 9.67-keV W-Lβline.The thickness distribution of the aperiodic multilayers was designed using the first Bragg diffraction condition and then optimized through a simplex algorithm to realize a narrow bandwidth and consistent spectral response.To enhance spectral accuracy,further refinements were undertaken by matching the grazing incidence X-ray reflectivity data with actual structural parameters.X-ray reflectivity measurements from the SSRF synchrotron radiation facility on the optimized sample showed a reflectivity of 29.7±2.6%,flat-band range of 1.3 keV,and bandwidth of 1.7 keV,making it suitable for high-temperature plasma diagnostics.The study explored the potential of predicting the 9.67 keV reflectivity spectrum using the fitting data from the grazing incidence X-ray reflectivity curves at 8.05 keV.Additionally,the short-term thermal stability of an aperiodic multilayer was assessed using temperature-dependent in situ X-ray measurements.Shifts in the reflectivity spectrum during annealing were attributed to interdiffusion and interfacial relaxation.The research team recommends the aperiodic Mo/B_(4)C multilayer mirror for operations below 300℃.展开更多
Stabilization of the axisymmetric magnetic mirror relies on the pressure-weighted magnetic field curvature.We report a new experiment by configuring a magnetic cusp structure to stabilize m=1 interchange mode in the K...Stabilization of the axisymmetric magnetic mirror relies on the pressure-weighted magnetic field curvature.We report a new experiment by configuring a magnetic cusp structure to stabilize m=1 interchange mode in the KMAX tandem mirror.The cusp configuration is formed by reversing currents in the two side cell coils,and a stronger cusp can lead to a more stable plasma once the null point of the cusp is less than 35–40 cm away from the device axis.The density fluctuations measured by four axial Langmuir probes are mitigated by 70%–80%.The stabilization effect is consistent with the prediction of a theoretical calculation.展开更多
The nuclear charge radius plays a vital role in determining the equation of state of isospin asymmetric nuclear matter.Based on the correlation between the differences in charge radii of mirror-partner nuclei and the ...The nuclear charge radius plays a vital role in determining the equation of state of isospin asymmetric nuclear matter.Based on the correlation between the differences in charge radii of mirror-partner nuclei and the slope parameter(L)of symmetry energy at the nuclear saturation density,an analysis of the calibrated slope parameter L was performed in finite nuclei.In this study,relativistic and nonrelativistic energy density functionals were employed to constrain the nuclear symmetry energy through the available databases of the mirror-pair nuclei^(36)Ca–^(36)S,^(38)Ca–^(38)Ar,and ^(54)Ni–^(54)Fe.The deduced nuclear symmetry energy was located in the range 29.89–31.85 MeV,and L of the symmetry energy essentially covered the range 22.50–51.55 MeV at the saturation density.Moreover,the extracted L_(s) at the sensitivity density p_(s)=0.10 fm^(-3) was located in the interval range 30.52–39.76 MeV.展开更多
Humans are able to overcome sensory perturbations imposed on their movements through motor learning. One of the key mechanisms to accomplish this is sensorimotor adaptation, an implicit, error-driven learning mechanis...Humans are able to overcome sensory perturbations imposed on their movements through motor learning. One of the key mechanisms to accomplish this is sensorimotor adaptation, an implicit, error-driven learning mechanism. Past work on sensorimotor adaptation focused mainly on adaptation to rotated visual feedback—A paradigm known as visuomotor rotation. Recent studies have shown that sensorimotor adaptation can also occur under mirror-reversed visual feedback. In visuomotor rotation, sensorimotor adaptation can be driven by both endpoint and online feedback [1] [2]. However, it’s not been clear whether both kinds of feedback can similarly drive adaptation under a mirror reversed perturbation. We performed a study to establish what kinds of feedback can drive adaptation under mirror reversal. In the first two conditions, the participants were asked to ignore visual feedback. In the first condition, we provided mirror reversed online feedback and endpoint feedback. We reproduced previous findings showing that online feedback elicited adaptation under mirror reversal. In a second condition, we provided mirror reversed endpoint feedback. However, in the second condition, we found that endpoint feedback alone failed to elicit adaptation. In a third condition, we provided both types of feedback at the same time, but in a conflicting way: endpoint feedback was non-reversed while online feedback was mirror reversed. The participants were asked to ignore online visual feedback and try to hit the target with help from veridical endpoint feedback. In the third condition, in which veridical endpoint feedback and mirror reversed online feedback were provided, adaptation still occurred. Our results showed that endpoint feedback did not elicit adaptation under mirror reversal but online feedback did. This dissociation between effects of endpoint feedback and online feedback on adaptation under mirror reversal suggests that adaptation under these different kinds of feedback might in fact operate via distinct mechanisms.展开更多
In the eyes of Croatian archaeologist Goran Durdevic,an ancient mirror can also reflect cultural exchanges along the ancient Silk Road.GORAN Durdevic,aged 35,is an archaeolo-gist from Croatia.Since 2013,following the ...In the eyes of Croatian archaeologist Goran Durdevic,an ancient mirror can also reflect cultural exchanges along the ancient Silk Road.GORAN Durdevic,aged 35,is an archaeolo-gist from Croatia.Since 2013,following the launch of the Belt and Road Initiative(BRI),there has been increasing cooperation between Chinese universities and those in B&R member countries.is entailed some Chinese universities expanding enrollment to include international students from those countries.In 2017,Goran,who was in Croatia at the time,saw the news of the enrollment and applied to study at the School of History at Capital Normal University in Beijing,China.During his six-year stay in China,he carried out comparative research on bronze mirrors from the Chinese Han Dynasty(206 BC-AD 220)and ancient Rome.When it comes to the Chinese and Western allusions pertaining to mirrors,Goran can name a list of ancient Chinese philosophies which are inspiring to him.“In the Tang Dynasty(618-907),people believed that by using copper as a mirror,one could check one’s physical appearance;by using people as a mirror,one could understand gains and losses;and by using history as a mirror,one could know the rise and fall of regimes.”展开更多
Understanding the China-U.S. relations from a historical perspective.WHEN President Xi Jinping met his U.S. counterpart Joe Biden on the sidelines of the G20 Summit in Bali in November, 2022, he said, "History is...Understanding the China-U.S. relations from a historical perspective.WHEN President Xi Jinping met his U.S. counterpart Joe Biden on the sidelines of the G20 Summit in Bali in November, 2022, he said, "History is the best textbook. We should take it as a mirror and let it guide the future."展开更多
The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has ...The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has met the engineering requirements on the ground will change, seriously affecting the imaging quality. In order to eliminate the influence of gravity and to ensure the consistency of space and ground, gravity unloading must be performed. In order to meet the requirements of processing and testing for the large aperture space mirror in the state of vertical optical axis, a universal gravity unloading device was proposed. It was an active support and used air cylinders to provide accurate unloading force. First, the design flow of gravity unloading was introduced;then the detailed design of the mechanical structure and control system was given;then the performance parameters of the two types of cylinders were tested and compared, including the force-pressure relationship curve and the force-position relationship curve;finally, the experimental verification of the gravity unloading device was carried out;for a mirror with an aperture of ?2100 mm, the gravity unloading device was designed and a vertical detection optical path was built. The test results showed that by using this gravity unloading device, the actual processing surface accuracy of the mirror was better than 1/50λ-RMS, which met the application requirement of the optical system. Thus, it can be seen that using this gravity unloading device can effectively unload the gravity of the mirror and realize the accurate processing and measurement of the mirror surface. .展开更多
Jane Eyre,a historic Mirror is from 3 aspects to illustrate the author's point of view in details,and the emphasis is according to the background of Victorian Age to express the society,the religion and the people...Jane Eyre,a historic Mirror is from 3 aspects to illustrate the author's point of view in details,and the emphasis is according to the background of Victorian Age to express the society,the religion and the people's spiritual and physical life of that time.展开更多
Two important motifs of The Magic Toyshop,mirrors and puppets,are highly symbolic.They,especially mirrors,play an important role in revealing the theme of Melanie’s growing pains at the cusp of adulthood.From narciss...Two important motifs of The Magic Toyshop,mirrors and puppets,are highly symbolic.They,especially mirrors,play an important role in revealing the theme of Melanie’s growing pains at the cusp of adulthood.From narcissistic proclivities to first“sexual”transgression,from falling victim to Uncle Philip’s manipulation to rebellion against him with her“hero”Finn,the hero⁃ine went through one hardship after another,gradually grew out of her reflection in the mirror and entered the adult world.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12375244,12135009,and 12275356)the Hunan Provincial Innovation Foun-dation for Postgraduate(Grant Nos.CX20210062 and CX20230006).
文摘Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-criticaldensity plasmas.It is found theoretically and numerically that the radiation pressure of a circularly polarized laser pulse first compresses the plasma electrons to form a dense flying mirror with a relativistic high speed.The pulse reflected by the mirror is red-shifted to the mid-infrared range.Full three-dimensional simulations demonstrate that the central wavelength of the mid-infrared pulse is tunable from 3µm to 14µm,and the laser energy conversion efficiency can reach as high as 13%.With a 0.5–10 PW incident laser pulse,the generated mid-infrared pulse reaches a peak power of 10–180 TW,which is interesting for various applications in ultrafast and high-field sciences.
文摘American Hollywood animated films have conquered the world.In recent years,many successful works have appeared in domestic animated films,bringing new vitality to the Chinese animated film industry.Based on Lacan’s Mirror Stage Theory,this study attempts to start from the bravery of Judy and Nezha,the protagonists of Zootopia(2016)and Nezha(2019).It analyzes and compares their embodiment,formation,influence and reflection with real society to solve the problems of the two brave characters’formation causes,characteristic differences and social influences,including racial discrimination,individualism in American society and family problems in Chinese society.This study sheds light on the transmission of intercultural values in animated films.
基金Z.Y.acknowledges the National Natural Science Foundation of China(Grant No.42074211)the Key Research Program of the Institute of Geology&Geophysics,Chinese Academy of Sciences(Grant No.IGGCAS-201904).
文摘A mirror mode wave is a fundamental magnetic structure in the planetary space environment that is persistently compressed by solar wind,especially in the magnetosheath.Mirror modes have been widely identified in the magnetosheaths of the Earth and other planets in the solar system,yet the understanding of mirror mode waves on extraterrestrial planets is not as comprehensive as that on the Earth.Using magnetic field data collected by the Cassini spacecraft,we found peak and dip types according to the magnetic morphology(i.e.,structures with higher or lower magnetic strengths than the background field).Moreover,mirror mode waves and electromagnetic ion cyclotron waves were found one after the other,implying that the two wave modes may evolve into one another in the Kronian magnetosheath.The results indicate that many fundamental plasma processes associated with the mirror mode structure exist in the Kronian magnetosheath.The energy conversion in Saturn’s magnetosheath may provide key insights that will aid in understanding giant planetary magnetospheric processes.
基金funded by the National Natural Science Foundation of China(No.11733005,12173041,11727805)Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2020376)Frontier Research Fund of Institute of Optics and Electronics,Chinese Academy of Sciences(No.C21K002).
文摘Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical surfaces,and the incorporation of the deformable mirror.Typically,voice-coil actuators are used,which require additional position sensors,internal control electronics,and cooling systems,leading to a very complex structure.Piezoelectric deformable secondary mirror technologies were proposed to overcome these problems.Recently,a high-order piezoelectric deformable secondary mirror has been developed and installed on the 1.8-m telescope at Lijiang Observatory in China to make it an adaptive telescope.The system consists of a 241-actuator piezoelectric deformable secondary mirror,a 192-sub-aperture Shack-Hartmann wavefront sensor,and a multi-core-based real-time controller.The actuator spacing of the PDSM measures 19.3 mm,equivalent to approximately 12.6 cm when mapped onto the primary mirror,significantly less than the voicecoil-based adaptive telescopes such as LBT,Magellan and VLT.As a result,stellar images with Strehl ratios above 0.49 in the R band have been obtained.To our knowledge,these are the highest R band images captured by an adaptive telescope with deformable secondary mirrors.Here,we report the system description and on-sky performance of this adaptive telescope.
文摘Since it was first described as a method to treat phantom limb pain, mirror therapy(MT) has been applied in many areas of rehabilitation. Its seminal application with the aim of restoring motor function following stroke is considered to be that of Altschuler et al.(1999).
文摘We study the space of stability conditions on K3 surfaces from the perspective of mirror symmetry. This is done in the attractor backgrounds(moduli). We find certain highly non-generic behaviors of marginal stability walls(a key notion in the study of wall crossings)in the space of stability conditions. These correspond via mirror symmetry to some nongeneric behaviors of special Lagrangians in an attractor background. The main results can be understood as a mirror correspondence in a synthesis of the homological mirror conjecture and SYZ mirror conjecture.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Nos.11875204 and U1932167)Fundamental Research Funds for the Central Universities(Nos.22120210446 and 22120180070)the Presidential Foundation of China Academy of Engineering Physics(No.YZJJLX2019011).
文摘Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems,which probe electron temperature and density during inertial confinement fusion processes.In this study,aperiodic Mo/B_(4)C multilayer mirrors of varied thick-nesses were investigated for X-ray plasma diagnostics at the 9.67-keV W-Lβline.The thickness distribution of the aperiodic multilayers was designed using the first Bragg diffraction condition and then optimized through a simplex algorithm to realize a narrow bandwidth and consistent spectral response.To enhance spectral accuracy,further refinements were undertaken by matching the grazing incidence X-ray reflectivity data with actual structural parameters.X-ray reflectivity measurements from the SSRF synchrotron radiation facility on the optimized sample showed a reflectivity of 29.7±2.6%,flat-band range of 1.3 keV,and bandwidth of 1.7 keV,making it suitable for high-temperature plasma diagnostics.The study explored the potential of predicting the 9.67 keV reflectivity spectrum using the fitting data from the grazing incidence X-ray reflectivity curves at 8.05 keV.Additionally,the short-term thermal stability of an aperiodic multilayer was assessed using temperature-dependent in situ X-ray measurements.Shifts in the reflectivity spectrum during annealing were attributed to interdiffusion and interfacial relaxation.The research team recommends the aperiodic Mo/B_(4)C multilayer mirror for operations below 300℃.
基金the National Key R&D Program of China(No.2017YFE0301802)National Natural Science Foundation of China(No.12175226).
文摘Stabilization of the axisymmetric magnetic mirror relies on the pressure-weighted magnetic field curvature.We report a new experiment by configuring a magnetic cusp structure to stabilize m=1 interchange mode in the KMAX tandem mirror.The cusp configuration is formed by reversing currents in the two side cell coils,and a stronger cusp can lead to a more stable plasma once the null point of the cusp is less than 35–40 cm away from the device axis.The density fluctuations measured by four axial Langmuir probes are mitigated by 70%–80%.The stabilization effect is consistent with the prediction of a theoretical calculation.
基金supported by the Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences,the National Natural Science Foundation of China(Nos.12135004,11635003,11961141004,12275025,and 11975096)the Fundamental Research Funds for Central Universities(No.2020NTST06).
文摘The nuclear charge radius plays a vital role in determining the equation of state of isospin asymmetric nuclear matter.Based on the correlation between the differences in charge radii of mirror-partner nuclei and the slope parameter(L)of symmetry energy at the nuclear saturation density,an analysis of the calibrated slope parameter L was performed in finite nuclei.In this study,relativistic and nonrelativistic energy density functionals were employed to constrain the nuclear symmetry energy through the available databases of the mirror-pair nuclei^(36)Ca–^(36)S,^(38)Ca–^(38)Ar,and ^(54)Ni–^(54)Fe.The deduced nuclear symmetry energy was located in the range 29.89–31.85 MeV,and L of the symmetry energy essentially covered the range 22.50–51.55 MeV at the saturation density.Moreover,the extracted L_(s) at the sensitivity density p_(s)=0.10 fm^(-3) was located in the interval range 30.52–39.76 MeV.
文摘Humans are able to overcome sensory perturbations imposed on their movements through motor learning. One of the key mechanisms to accomplish this is sensorimotor adaptation, an implicit, error-driven learning mechanism. Past work on sensorimotor adaptation focused mainly on adaptation to rotated visual feedback—A paradigm known as visuomotor rotation. Recent studies have shown that sensorimotor adaptation can also occur under mirror-reversed visual feedback. In visuomotor rotation, sensorimotor adaptation can be driven by both endpoint and online feedback [1] [2]. However, it’s not been clear whether both kinds of feedback can similarly drive adaptation under a mirror reversed perturbation. We performed a study to establish what kinds of feedback can drive adaptation under mirror reversal. In the first two conditions, the participants were asked to ignore visual feedback. In the first condition, we provided mirror reversed online feedback and endpoint feedback. We reproduced previous findings showing that online feedback elicited adaptation under mirror reversal. In a second condition, we provided mirror reversed endpoint feedback. However, in the second condition, we found that endpoint feedback alone failed to elicit adaptation. In a third condition, we provided both types of feedback at the same time, but in a conflicting way: endpoint feedback was non-reversed while online feedback was mirror reversed. The participants were asked to ignore online visual feedback and try to hit the target with help from veridical endpoint feedback. In the third condition, in which veridical endpoint feedback and mirror reversed online feedback were provided, adaptation still occurred. Our results showed that endpoint feedback did not elicit adaptation under mirror reversal but online feedback did. This dissociation between effects of endpoint feedback and online feedback on adaptation under mirror reversal suggests that adaptation under these different kinds of feedback might in fact operate via distinct mechanisms.
文摘In the eyes of Croatian archaeologist Goran Durdevic,an ancient mirror can also reflect cultural exchanges along the ancient Silk Road.GORAN Durdevic,aged 35,is an archaeolo-gist from Croatia.Since 2013,following the launch of the Belt and Road Initiative(BRI),there has been increasing cooperation between Chinese universities and those in B&R member countries.is entailed some Chinese universities expanding enrollment to include international students from those countries.In 2017,Goran,who was in Croatia at the time,saw the news of the enrollment and applied to study at the School of History at Capital Normal University in Beijing,China.During his six-year stay in China,he carried out comparative research on bronze mirrors from the Chinese Han Dynasty(206 BC-AD 220)and ancient Rome.When it comes to the Chinese and Western allusions pertaining to mirrors,Goran can name a list of ancient Chinese philosophies which are inspiring to him.“In the Tang Dynasty(618-907),people believed that by using copper as a mirror,one could check one’s physical appearance;by using people as a mirror,one could understand gains and losses;and by using history as a mirror,one could know the rise and fall of regimes.”
文摘Understanding the China-U.S. relations from a historical perspective.WHEN President Xi Jinping met his U.S. counterpart Joe Biden on the sidelines of the G20 Summit in Bali in November, 2022, he said, "History is the best textbook. We should take it as a mirror and let it guide the future."
文摘The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has met the engineering requirements on the ground will change, seriously affecting the imaging quality. In order to eliminate the influence of gravity and to ensure the consistency of space and ground, gravity unloading must be performed. In order to meet the requirements of processing and testing for the large aperture space mirror in the state of vertical optical axis, a universal gravity unloading device was proposed. It was an active support and used air cylinders to provide accurate unloading force. First, the design flow of gravity unloading was introduced;then the detailed design of the mechanical structure and control system was given;then the performance parameters of the two types of cylinders were tested and compared, including the force-pressure relationship curve and the force-position relationship curve;finally, the experimental verification of the gravity unloading device was carried out;for a mirror with an aperture of ?2100 mm, the gravity unloading device was designed and a vertical detection optical path was built. The test results showed that by using this gravity unloading device, the actual processing surface accuracy of the mirror was better than 1/50λ-RMS, which met the application requirement of the optical system. Thus, it can be seen that using this gravity unloading device can effectively unload the gravity of the mirror and realize the accurate processing and measurement of the mirror surface. .
文摘Jane Eyre,a historic Mirror is from 3 aspects to illustrate the author's point of view in details,and the emphasis is according to the background of Victorian Age to express the society,the religion and the people's spiritual and physical life of that time.
文摘Two important motifs of The Magic Toyshop,mirrors and puppets,are highly symbolic.They,especially mirrors,play an important role in revealing the theme of Melanie’s growing pains at the cusp of adulthood.From narcissistic proclivities to first“sexual”transgression,from falling victim to Uncle Philip’s manipulation to rebellion against him with her“hero”Finn,the hero⁃ine went through one hardship after another,gradually grew out of her reflection in the mirror and entered the adult world.
