A specimen collected from the Lower Cretaceous Yixian Formation of western Liaoning, China, represents a new genus and species of troodontid theropod. The new taxon is named and described on the basis of the holotype ...A specimen collected from the Lower Cretaceous Yixian Formation of western Liaoning, China, represents a new genus and species of troodontid theropod. The new taxon is named and described on the basis of the holotype and the only known specimen, which comprises an articulated skeleton with the presacral vertebral, shoulder girdle and forelimbs missing as preserved. Diagnostic features of the new species include nasals that are sinusoid in lateral view, absence of a passage connecting the antorbital and maxillary fenestrae, relatively large teeth, plate-like chevrons forming a band along most of the length of the tail, and a long neck between the femoral head and shaft. The temporal constraints of the three paravian groups (Troodontidae, Dromaeosauridae and Aves) combined with the character distributions among the earliest known troodontids indicate a rapid evolution at the base of the Troodontidae.展开更多
Pygostyle was previously considered as a unique structure of ornithothoracine birds, used to maneuver tail feathers. A similar structure from an oviraptorosaurian dinosaur was considered functionally associated with t...Pygostyle was previously considered as a unique structure of ornithothoracine birds, used to maneuver tail feathers. A similar structure from an oviraptorosaurian dinosaur was considered functionally associated with the rectrices as in birds. We report a pygostyle-like structure from a therizinosauroid dinosaur. The presence of filamentous integuments, but absence of rectrices, on the tail of this therizinosauroid, combined with other lines of evidence, suggests that the initial function of the pygostyle was not related to the rectrices.展开更多
A new specimen consisting of a complete skull and lower jaw was discovered from the Lujiatun bed of the Lower Cretaceous Yixian Formation in the Lujiatun site, Beipiao, western Liaoning Province. It represents an adul...A new specimen consisting of a complete skull and lower jaw was discovered from the Lujiatun bed of the Lower Cretaceous Yixian Formation in the Lujiatun site, Beipiao, western Liaoning Province. It represents an adult specimen of Hongshanosaurus houi. Comparative studies show that Hongshanosaurus is distinguishable from its sister taxon Psittacosaurus by having the preorbital portion about half of the basal skull length, and the elliptical external naris, orbit, and a lower temporal fenestra oriented caudodorsally.展开更多
Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impac...Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impact of different synthetic strategies on the fundamental nature of NCs,such as nonradiative recombination centers,remains poorly understood.In this study,we investigated the photophysical properties of CsPbBr_(3) NCs synthesized using two distinct methods,hot injection and ligand-assisted reprecipitation,at the individual particle level.We observed different blinking behaviors under specific photoexcitation power densities and proposed,through intensity-lifetime analysis and Monte-Carlo simulations,that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels,which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs.Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs,with significant implications for their use in optoelectronic and other technological applications.展开更多
To the Editor:Multiple myeloma(MM)is a plasma cell disease that remains incurable.Novel anti-MMtherapies are currently in clinical research,including CAR-T therapy,bispecific antibodies,and XPO1 inhibitors1.XPO1 is a ...To the Editor:Multiple myeloma(MM)is a plasma cell disease that remains incurable.Novel anti-MMtherapies are currently in clinical research,including CAR-T therapy,bispecific antibodies,and XPO1 inhibitors1.XPO1 is a nuclear export protein that helps leucine-rich proteins transport from the nucleus to the cytoplasm.XPO1 is highly expressed in patients with MM and XPO1 overexpression is associated with short PFS and OS^(2).These observations suggest that XPO1 has considerable value as a therapeutic target for patients with MM.展开更多
A DC current sensor based on an optically pumped atomic magnetometer is proposed.It has a high linearity in a wide operation range,since the magnetometer measures the absolute magnitude of the magnetic field produced ...A DC current sensor based on an optically pumped atomic magnetometer is proposed.It has a high linearity in a wide operation range,since the magnetometer measures the absolute magnitude of the magnetic field produced by the current to be measured.The current sensor exhibits a high accuracy with a non-moment solenoid and magnetic shielding to suppress the influence from the environment.The absolute error of the measured current is below 0.08 m A when the range is from 7.5 m A to 750 m A.The relative error is 5.54×10^-5 at 750 m A.展开更多
To efficiently plan the point-to-point path for a 7-degrees-of-freedom(7-DOF)free-floating space manipulator system,a path planning method based on Legendre pseudospectral convex programming(LPCP)is proposed.First,the...To efficiently plan the point-to-point path for a 7-degrees-of-freedom(7-DOF)free-floating space manipulator system,a path planning method based on Legendre pseudospectral convex programming(LPCP)is proposed.First,the non-convex dynamics are approximated by utilizing the first-order Taylor expansion in the vicinity of the initial guess path,which results in a convex system.Next,the linearized dynamics are discretized at Legendre-Gauss-Lobatto collocation points to transcribe the differential equations to a set of equality constraints.To obtain a reliable initial guess trajectory,the auxiliary path planning problem of the 7-DOF space manipulator with a fixed base is initially resolved.Additionally,the penalty function method is introduced to enhance the convergence performance of the LPCP.Finally,simulation results show that the proposed algorithm in this paper can generate the point-to-point path and has higher computational efficiency than the general sequential convex programming method while ensuring optimality.展开更多
This paper presents a novel hybrid method to design the continuous and accurate multi-gravity-assist trajectory for a high-fidelity dynamics.The gravitational perturbation of the primary body is considered during the ...This paper presents a novel hybrid method to design the continuous and accurate multi-gravity-assist trajectory for a high-fidelity dynamics.The gravitational perturbation of the primary body is considered during the gravity assistance.The pseudostate technique is applied to approximate the gravity-assisted trajectory,where the optimal sweepback duration is solved using a trained deep neural network.The major factors that affect the optimal sweepback duration of the approach and departure segments are investigated.The results show that the optimal sweepback duration of the approach segment only relies on the shape of the approach trajectory and is independent of the flight time.Then,a gravity-assisted trajectory patched strategy and a hybrid algorithm combining the particle swarm optimization and the sequential quadratic programming are developed to optimize the multi-gravity-assist trajectory.The proposed hybrid method is applied to the Europa orbiter mission.In comparison with the traditional patched conic method,this method demonstrates outstanding performance on accuracy and significantly reduces the computational time and complexity of the trajectory correction with the high-fidelity dynamics.展开更多
Through wet-chemical assembly methods, gold nanorods were placed close to each other and formed a dimer with a gap distance *1 nm, and hence degenerated plasmonic dipole modes of individual nanorods coupled together t...Through wet-chemical assembly methods, gold nanorods were placed close to each other and formed a dimer with a gap distance *1 nm, and hence degenerated plasmonic dipole modes of individual nanorods coupled together to produce hybridized bonding and antibonding resonance modes. Previous studies using a condenser for illumination result in averaged signals over all excitation angles. By exciting an individual dimer obliquely at different angles, we demonstrate that these two new resonance modes are highly tunable and sensitive to the angle between the excitation polarization and the dimer orientation, which follows cos2 u dependence. Moreover, for dimer structures with various structure angles, the resonance wavelengths as well as the refractive index sensitivities were found independent of the structure angle. Calculated angle-resolved plasmonic properties are in good agreement with the measurements. The assembled nanostructures investigated here are important for fundamental researches as well as potential applications when they are used as building blocks in plasmon-based optical and optoelectronic devices.展开更多
Station-keeping(SK) is indispensable in actual geostationary(GEO) satellite missions. Due to the luni-solar gravity perturbations, the inclination of a GEO satellite suffers the issues of secular drift and long-period...Station-keeping(SK) is indispensable in actual geostationary(GEO) satellite missions. Due to the luni-solar gravity perturbations, the inclination of a GEO satellite suffers the issues of secular drift and long-period oscillation. Current north-south(NS)SK strategies maintain the GEO satellite’s orbit with high accuracy but low fuel efficiency. In this work, an efficient highaccuracy NS-SK strategy is developed for the GEO satellites. First, an averaging method is employed to decrease the accumulation of the secular drift within a one-solar-day SK cycle, while the long-period oscillation caused by the solar gravity is damped to further improve the orbital accuracy using the impulse and finite-thrust propulsions. Second, we contribute a fueloptimal cycle that reduces the fuel consumption and a fixed-interval cycle that executes SK control in fixed time interval every day to further enhance the proposed NS-SK strategy. Numerical simulations show that the improved strategy can achieve highaccuracy NS-SK with little fuel consumption. Moreover, results also demonstrate that the fixed-interval cycle can reach higher NS-SK accuracy while consuming less fuel.展开更多
Ancient books that record the history of different periods are precious for human civilization.But the protection of them is facing serious problems such as aging.It is significant to repair the damaged characters in ...Ancient books that record the history of different periods are precious for human civilization.But the protection of them is facing serious problems such as aging.It is significant to repair the damaged characters in ancient books and restore their original textures.The requirement of the restoration of the damaged character is keeping the stroke shape correct and the font style consistent.In order to solve these problems,this paper proposes a new restoration method based on generative adversarial networks.We use the shape restoration network to complete the stroke shape recovery and the font style recovery.The texture repair network is responsible for reconstructing texture details.In order to improve the accuracy of the generator in the shape restoration network,we use the adversarial feature loss(AFL),which can update the generator and discriminator synchronously to replace the traditional perceptual loss.Meanwhile,the font style loss is proposed to maintain the stylistic consistency for the whole character.Our model is evaluated on the datasets Yi and Qing,and shows that it outperforms current state-of-the-art techniques quantitatively and qualitatively.In particular,the Structural Similarity has increased by 8.0%and 6.7%respectively on the two datasets.展开更多
Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source a...Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source and difficulties of controllable formation of morphology and size. Herein, one-pot biosynthesis of gold nanoplates is proposed, in which cheap yeast was extracted as a green precursor. The morphologies and sizes of the gold nanostructures can be controlled via varying the pH value of the biomedium. In acid condition, gold nanoplates with side length from 1300 ± 200 to 300 ± 100 nm and height from 18 to 15 nm were obtained by increasing the pH value. Whereas, in neutral or basic condition, only gold nanoflowers and nanoparticles were obtained. It was determined that organic molecules, such as succinic acid, lactic acid, malic acid, and glutathione, which are generated in metabolism process, played important role in the reduction of gold ions. Besides, it was found that the gold nanoplates exhibited plasmonic property with prominent dipole infrared resonance in near-infrared region, indicating their potential in surface plasmon-enhanced applications, such as bioimaging and photothermal therapy.展开更多
From March 20,2019 to April 30,2019,the 10th China Trajectory Optimization Competition(CTOC10)was jointly held by the Chinese Society of Theoretical and Applied Mechanics and Nanjing University of Aeronautics and Astr...From March 20,2019 to April 30,2019,the 10th China Trajectory Optimization Competition(CTOC10)was jointly held by the Chinese Society of Theoretical and Applied Mechanics and Nanjing University of Aeronautics and Astronautics.The CTOC10 focused on trajectory optimization for Jovian exploration.The team from Harbin Institute of Technology won the first prize.In this paper,first,the history of the CTOC is presented.Subsequently,the mission of the CTOC10 is introduced,and an account of the final rankings of the competition is given.Finally,trajectory optimization methods are discussed,and suggestions for practical missions are provided.展开更多
基金the National Natural Science Foundation of ChinaNational Geographic Socicty+1 种基金Special Funds for Major State Basic Research Projects of China Chinese Acalemy of Sciences for financial support.
文摘A specimen collected from the Lower Cretaceous Yixian Formation of western Liaoning, China, represents a new genus and species of troodontid theropod. The new taxon is named and described on the basis of the holotype and the only known specimen, which comprises an articulated skeleton with the presacral vertebral, shoulder girdle and forelimbs missing as preserved. Diagnostic features of the new species include nasals that are sinusoid in lateral view, absence of a passage connecting the antorbital and maxillary fenestrae, relatively large teeth, plate-like chevrons forming a band along most of the length of the tail, and a long neck between the femoral head and shaft. The temporal constraints of the three paravian groups (Troodontidae, Dromaeosauridae and Aves) combined with the character distributions among the earliest known troodontids indicate a rapid evolution at the base of the Troodontidae.
基金supported by grants from the National Natural Science Foundation of China(No.40125006)the Special Funds for Major State Basic Research Projects of China(No.G2000077700)the Chinese Academy of Sciences(No.KZCX3-J-03).
文摘Pygostyle was previously considered as a unique structure of ornithothoracine birds, used to maneuver tail feathers. A similar structure from an oviraptorosaurian dinosaur was considered functionally associated with the rectrices as in birds. We report a pygostyle-like structure from a therizinosauroid dinosaur. The presence of filamentous integuments, but absence of rectrices, on the tail of this therizinosauroid, combined with other lines of evidence, suggests that the initial function of the pygostyle was not related to the rectrices.
文摘A new specimen consisting of a complete skull and lower jaw was discovered from the Lujiatun bed of the Lower Cretaceous Yixian Formation in the Lujiatun site, Beipiao, western Liaoning Province. It represents an adult specimen of Hongshanosaurus houi. Comparative studies show that Hongshanosaurus is distinguishable from its sister taxon Psittacosaurus by having the preorbital portion about half of the basal skull length, and the elliptical external naris, orbit, and a lower temporal fenestra oriented caudodorsally.
基金supported by the National Natural Science Foundation of China(Nos.22073046,62011530133)the Fundamental Research Funds for the Central Universities(Nos.020514380256,020514380278)+1 种基金the Double-Innovation Doctor Program of Jiangsu Province,China(No.JSSCBS20211151)the Funding for School-level Research Projects of Yancheng Institute of Technology(No.xjr2021062).
文摘Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impact of different synthetic strategies on the fundamental nature of NCs,such as nonradiative recombination centers,remains poorly understood.In this study,we investigated the photophysical properties of CsPbBr_(3) NCs synthesized using two distinct methods,hot injection and ligand-assisted reprecipitation,at the individual particle level.We observed different blinking behaviors under specific photoexcitation power densities and proposed,through intensity-lifetime analysis and Monte-Carlo simulations,that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels,which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs.Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs,with significant implications for their use in optoelectronic and other technological applications.
基金supported by grants from the National Natural Science Foundation of China(Nos.82070223 and 82370205)the Social Development Project of Jiangsu Science and Technology Plan(No.BE2022810,China).
文摘To the Editor:Multiple myeloma(MM)is a plasma cell disease that remains incurable.Novel anti-MMtherapies are currently in clinical research,including CAR-T therapy,bispecific antibodies,and XPO1 inhibitors1.XPO1 is a nuclear export protein that helps leucine-rich proteins transport from the nucleus to the cytoplasm.XPO1 is highly expressed in patients with MM and XPO1 overexpression is associated with short PFS and OS^(2).These observations suggest that XPO1 has considerable value as a therapeutic target for patients with MM.
文摘A DC current sensor based on an optically pumped atomic magnetometer is proposed.It has a high linearity in a wide operation range,since the magnetometer measures the absolute magnitude of the magnetic field produced by the current to be measured.The current sensor exhibits a high accuracy with a non-moment solenoid and magnetic shielding to suppress the influence from the environment.The absolute error of the measured current is below 0.08 m A when the range is from 7.5 m A to 750 m A.The relative error is 5.54×10^-5 at 750 m A.
基金supported by the National Natural Science Foundation of China(grant no.11972182)the Science and Technology on Space Intelligent Control Laboratory(nos.HTKJ2022KL502014 and 2021-JCJQ-LB-010-08).
文摘To efficiently plan the point-to-point path for a 7-degrees-of-freedom(7-DOF)free-floating space manipulator system,a path planning method based on Legendre pseudospectral convex programming(LPCP)is proposed.First,the non-convex dynamics are approximated by utilizing the first-order Taylor expansion in the vicinity of the initial guess path,which results in a convex system.Next,the linearized dynamics are discretized at Legendre-Gauss-Lobatto collocation points to transcribe the differential equations to a set of equality constraints.To obtain a reliable initial guess trajectory,the auxiliary path planning problem of the 7-DOF space manipulator with a fixed base is initially resolved.Additionally,the penalty function method is introduced to enhance the convergence performance of the LPCP.Finally,simulation results show that the proposed algorithm in this paper can generate the point-to-point path and has higher computational efficiency than the general sequential convex programming method while ensuring optimality.
基金supported by the National Natural Science Foundation of China(Grant No.61273051)the Qing Lan Project,Funding for Outstanding Doctoral Dissertation in NUAA(Grant No.BCXJ19-12)the State Scholarship from China Scholarship Council(Grant No.201906830066)。
文摘This paper presents a novel hybrid method to design the continuous and accurate multi-gravity-assist trajectory for a high-fidelity dynamics.The gravitational perturbation of the primary body is considered during the gravity assistance.The pseudostate technique is applied to approximate the gravity-assisted trajectory,where the optimal sweepback duration is solved using a trained deep neural network.The major factors that affect the optimal sweepback duration of the approach and departure segments are investigated.The results show that the optimal sweepback duration of the approach segment only relies on the shape of the approach trajectory and is independent of the flight time.Then,a gravity-assisted trajectory patched strategy and a hybrid algorithm combining the particle swarm optimization and the sequential quadratic programming are developed to optimize the multi-gravity-assist trajectory.The proposed hybrid method is applied to the Europa orbiter mission.In comparison with the traditional patched conic method,this method demonstrates outstanding performance on accuracy and significantly reduces the computational time and complexity of the trajectory correction with the high-fidelity dynamics.
基金supported by the National Natural Science Foundation of China (NSFC) (grant no. 61178014, 11274231, and 21271181)the key project of the Ministry of Education of China under grant 109061+1 种基金Ministry of Science and Technology of China (Inter-governmental S&T Cooperation Project, grant no. 6–10)Thousand Youth Talents Program of China
文摘Through wet-chemical assembly methods, gold nanorods were placed close to each other and formed a dimer with a gap distance *1 nm, and hence degenerated plasmonic dipole modes of individual nanorods coupled together to produce hybridized bonding and antibonding resonance modes. Previous studies using a condenser for illumination result in averaged signals over all excitation angles. By exciting an individual dimer obliquely at different angles, we demonstrate that these two new resonance modes are highly tunable and sensitive to the angle between the excitation polarization and the dimer orientation, which follows cos2 u dependence. Moreover, for dimer structures with various structure angles, the resonance wavelengths as well as the refractive index sensitivities were found independent of the structure angle. Calculated angle-resolved plasmonic properties are in good agreement with the measurements. The assembled nanostructures investigated here are important for fundamental researches as well as potential applications when they are used as building blocks in plasmon-based optical and optoelectronic devices.
基金supported by the National Natural Science Foundation of China(Grant No.61273051)Qing Lan Projectthe Funding for Outstanding Doctoral Dissertation in Nanjing University of Aeronautics and Astronautics(NUAA)(Grant No.BCXJ19-12)。
文摘Station-keeping(SK) is indispensable in actual geostationary(GEO) satellite missions. Due to the luni-solar gravity perturbations, the inclination of a GEO satellite suffers the issues of secular drift and long-period oscillation. Current north-south(NS)SK strategies maintain the GEO satellite’s orbit with high accuracy but low fuel efficiency. In this work, an efficient highaccuracy NS-SK strategy is developed for the GEO satellites. First, an averaging method is employed to decrease the accumulation of the secular drift within a one-solar-day SK cycle, while the long-period oscillation caused by the solar gravity is damped to further improve the orbital accuracy using the impulse and finite-thrust propulsions. Second, we contribute a fueloptimal cycle that reduces the fuel consumption and a fixed-interval cycle that executes SK control in fixed time interval every day to further enhance the proposed NS-SK strategy. Numerical simulations show that the improved strategy can achieve highaccuracy NS-SK with little fuel consumption. Moreover, results also demonstrate that the fixed-interval cycle can reach higher NS-SK accuracy while consuming less fuel.
基金the National Social Science Foundation of China under Grant 19BYY171the Fundamental Research Funds for the Central Universities under Grant XDJK2013C117+4 种基金Ph.D.Fund of Southwest University No.20130553China Postdoctoral Science Foundation under Grant 2015M580765Chongqing Postdoctoral Science Foundation under Grant Xm2016041Chongqing Natural Science Foundation(cstc2019jcyj-msxmX0130)Chongqing City science and technology education research projects(KJQN201801901).
文摘Ancient books that record the history of different periods are precious for human civilization.But the protection of them is facing serious problems such as aging.It is significant to repair the damaged characters in ancient books and restore their original textures.The requirement of the restoration of the damaged character is keeping the stroke shape correct and the font style consistent.In order to solve these problems,this paper proposes a new restoration method based on generative adversarial networks.We use the shape restoration network to complete the stroke shape recovery and the font style recovery.The texture repair network is responsible for reconstructing texture details.In order to improve the accuracy of the generator in the shape restoration network,we use the adversarial feature loss(AFL),which can update the generator and discriminator synchronously to replace the traditional perceptual loss.Meanwhile,the font style loss is proposed to maintain the stylistic consistency for the whole character.Our model is evaluated on the datasets Yi and Qing,and shows that it outperforms current state-of-the-art techniques quantitatively and qualitatively.In particular,the Structural Similarity has increased by 8.0%and 6.7%respectively on the two datasets.
基金supported by the National Key Research and Development Program of China(2016YFC0102700)National Natural Science Foundation of China(21171117,21271181,21473240,and 81270209)+1 种基金Medical-Engineering Crossover Fund of Shanghai Jiao Tong University(YG2015MS51 and YG2014MS66)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning
文摘Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source and difficulties of controllable formation of morphology and size. Herein, one-pot biosynthesis of gold nanoplates is proposed, in which cheap yeast was extracted as a green precursor. The morphologies and sizes of the gold nanostructures can be controlled via varying the pH value of the biomedium. In acid condition, gold nanoplates with side length from 1300 ± 200 to 300 ± 100 nm and height from 18 to 15 nm were obtained by increasing the pH value. Whereas, in neutral or basic condition, only gold nanoflowers and nanoparticles were obtained. It was determined that organic molecules, such as succinic acid, lactic acid, malic acid, and glutathione, which are generated in metabolism process, played important role in the reduction of gold ions. Besides, it was found that the gold nanoplates exhibited plasmonic property with prominent dipole infrared resonance in near-infrared region, indicating their potential in surface plasmon-enhanced applications, such as bioimaging and photothermal therapy.
基金This work was partially supported by the National Natural Science Foundation of China(No.11972182)sponsored by the Qing Lan Project,funded by the Science and Technology on Space Intelligent Control Laboratory(No.KGJZDSYS-2018-11)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX200220)Funding for Outstanding Doctoral Dissertation in NUAA(No.BCXJ19-12).The authors fully appreciate their financial supports.
文摘From March 20,2019 to April 30,2019,the 10th China Trajectory Optimization Competition(CTOC10)was jointly held by the Chinese Society of Theoretical and Applied Mechanics and Nanjing University of Aeronautics and Astronautics.The CTOC10 focused on trajectory optimization for Jovian exploration.The team from Harbin Institute of Technology won the first prize.In this paper,first,the history of the CTOC is presented.Subsequently,the mission of the CTOC10 is introduced,and an account of the final rankings of the competition is given.Finally,trajectory optimization methods are discussed,and suggestions for practical missions are provided.
