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| 1 | Mission Design of an Aperture-Synthetic Interferometer System for Space-Based Exoplanet Exploration显示文摘In recent years,exoplanet detection has become the technological frontier in the field of astronomy,because it provides evidence of the origin of life and the future human habitable exoplanet.Deploying several satellites to form an aperture-synthetic interferometer system in space may help discover“another Earth”via interferometry and midinfrared broadband spectroscopy.This paper analyzes a space-based exoplanet exploration mission in terms of the scientific background,mission profile,trajectory design,and orbital maintenance.First,the system architecture and working principle of the interferometer system are briefly introduced.Secondly,the mission orbit and corresponding transfer trajectories are discussed.The halo orbit near the Sun-Earth L2(SEL2)orbit is chosen as the candidate mission orbit.The low-energy transfer via stable invariant manifold with multiple perigees is designed,and the proper launch windows are presented.A speed increment less than 10 m/s is imposed for each transfer to achieve the insertion of the halo orbit.Finally,the tangent targeting method(TTM)is applied for high-precision formation maintenance with the whole velocity increments of less than 5×10^(−4)m/s for each spacecraft when the error bound is 0.1 m.The overall fuel budget during the mission period is evaluated and compared.The design in this paper will provide technical support and reliable reference for future exoplanet exploration missions. | Feida Jia Xiangyu Li Zhuoxi Huo Dong Qiao | 2022 | Space(Science & Technology)2022，，1： | 1 |
| 2 | Bexarotene improves motor function after spinal cord injury in mice显示文摘Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with spinal cord injury.Bexarotene,a type of retinoid,exerts therapeutic effects on patients with cutaneous T-cell lymphoma and Parkinson's disease.Bexarotene has been proven to promote autophagy,but it has not been used in the treatment of spinal cord injury.To investigate the effects of bexarotene on spinal cord injury,we established a mouse model of T11–T12 spinal cord contusion and performed daily intraperitoneal injection of bexarotene for 5 consecutive days.We found that bexarotene effectively reduced the deposition of collagen and the number of pathological neurons in the injured spinal cord,increased the number of synapses of nerve cells,reduced oxidative stress,inhibited pyroptosis,promoted the recovery of motor function,and reduced death.Inhibition of autophagy with 3-methyladenine reversed the effects of bexarotene on spinal cord injury.Bexarotene enhanced the nuclear translocation of transcription factor E3,which further activated AMP-activated protein kinase-S-phase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signaling pathways.Intravenous injection of transcription factor E3 sh RNA or intraperitoneal injection of compound C,an AMP-activated protein kinase blocker,inhibited the effects of bexarotene.These findings suggest that bexarotene regulates nuclear translocation of transcription factor E3 through the AMP-activated protein kinase-Sphase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signal pathways,promotes autophagy,decreases reactive oxygen species level,inhibits pyroptosis,and improves motor function after spinal cord injury. | Xingyu Wang Zhihao Shen Haojie Zhang Hao-Jie Zhang Feida Li Letian Yu Hua Chen Kailiang Zhou Hui Xu Sunren Sheng | 2023 | Neural Regeneration Research2023，18，12： | 1 |
| 3 | CEO Gender,Ethical Leadership,and Accounting Conservatism显示文摘 | Simon S M Ho Annie Yuansha Li Kinsun Tam Feida Zhang | 2014 | Journal of Business Ethics2014，127，2： | 1 |
| 4 | Does accounting conservatism improve the corporate information envi- ronment 显示文摘 | Hu Jinshuai Li Annie Yuansha Zhang Feida | 2014 | Joumal of International Accounting Auditing & Taxation2014，23，01： | 1 |
| 5 | Defects production and mechanical properties of typical metal engineering materials under neutron irradiation显示文摘Maintaining the safety and reliability of nuclear engineering materials under a neutron irradiation environment is significant. Atomic-scale simulations are conducted to investigate the mechanism of irradiation-induced vacancy formation in CLAM, F82 H and α-Fe with different neutron energies and objective laws of the effect of vacancy concentration on mechanical properties of α-Fe. Damage of these typical metal engineering materials caused by neutrons is mainly displacement damage, while the displacement damage rate and the non-ionizing effect of neutrons decrease with the increase of neutron energy. The elastic modulus, yield strength, and ultimate strength of α-Fe are in the order of magnitude of GPa. However, the elastic modulus is not constant but decreases with the increase of strain at the elastic deformation stage. The ultimate strength reaches its maximum value when vacancy concentration in α-Fe is 0.2%. On this basis, decreasing or increasing the number of vacancies reduces the ultimate strength. | LIU Jian TANG XiaoBin CHEN FeiDa HUANG Hai LI Huan YANG YaHui | 2015 | Science China(Technological Sciences)2015，58，10： | 0 |
| 6 | Regularized focusing inversion for large-scale gravity data based on GPU parallel computing显示文摘Processing large-scale 3-D gravity data is an important topic in geophysics field. Many existing inversion methods lack the competence of processing massive data and practical application capacity. This study proposes the application of GPU parallel processing technology to the focusing inversion method, aiming at improving the inversion accuracy while speeding up calculation and reducing the memory consumption, thus obtaining the fast and reliable inversion results for large complex model. In this paper, equivalent storage of geometric trellis is used to calculate the sensitivity matrix, and the inversion is based on GPU parallel computing technology. The parallel computing program that is optimized by reducing data transfer, access restrictions and instruction restrictions as well as latency hiding greatly reduces the memory usage, speeds up the calculation, and makes the fast inversion of large models possible. By comparing and analyzing the computing speed of traditional single thread CPU method and CUDA-based GPU parallel technology, the excellent acceleration performance of GPU parallel computing is verified, which provides ideas for practical application of some theoretical inversion methods restricted by computing speed and computer memory. The model test verifies that the focusing inversion method can overcome the problem of severe skin effect and ambiguity of geological body boundary. Moreover, the increase of the model cells and inversion data can more clearly depict the boundary position of the abnormal body and delineate its specific shape. | WANG Haoran DING Yidan LI Feida LI Jing | 2019 | Global Geology2019，22，3： | 0 |
| 7 | Efficient optimization method for variable-specific-impulse low-thrust trajectories with shutdown constraint显示文摘This paper develops a sequential convex programming(SCP)-based method to solve the minimum-fuel variable-specific-impulse low-thrust transfer problem considering shutdown constraint,with emphasize on improving the computational efficiency.The variable parameter engine is more applicable for many low-thrust scenarios,therefore,both a continuously variable model and a ladder variable model are adopted.First,the original problem is convexified by processing the constraint feasible domain,which is composed of the nonlinear dynamic equations and second-order equality constraint,into convex sets.Then,the approximation is generated to close the optimal solution of the low-thrust problem by iteratively solving the convexified subproblem.Moreover,the switching self-detection and adaptive node refinement methods are presented,which can improve the accuracy of the solution and accelerate the convergence during the approximation process and is especially necessary and effective in the scenarios with shutdown constraint.In numerical simulations,the comparison with the homotopic approach shows that the proposed method only needs 4%computational time as that of the homotopic approach,and two variable-specificimpulse examples further demonstrate the effectiveness and efficiency of the proposed method. | JIA FeiDa QIAO Dong HAN HongWei LI XiangYu | 2022 | Science China(Technological Sciences)2022，65，3： | 0 |
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