Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide i...Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.展开更多
An indoor positioning method for robots is presented to improve the precision of displacement measurement using only low-cost inertial measurement units(IMUs).Firstly,a high-fidelity displacement estimation for linear...An indoor positioning method for robots is presented to improve the precision of displacement measurement using only low-cost inertial measurement units(IMUs).Firstly,a high-fidelity displacement estimation for linear motion is proposed.A new robot motion model is designed as well as an axis alignment that only uses a single axis of the accelerometer.The integral error of velocity is eliminated by a new subsection calculation method.Two complementary IMUs are combined by assigning them different weights to obtain high accuracy displacement results.Secondly,an orientation estimation based on a fusion filter for the steering motion is proposed.Experiments show that the proposed method significantly improves the accuracy of linear motion measurement and is effective for the indoor positioning of a robot.展开更多
The Quantum Science Experiment Satellite(QUSES) is the first satellite deployed successfully in nearEarth space for quantum scientific experiments in the world, in which experimental study on the fundamental questions...The Quantum Science Experiment Satellite(QUSES) is the first satellite deployed successfully in nearEarth space for quantum scientific experiments in the world, in which experimental study on the fundamental questions of quantum mechanics can be done under the condition of a spatial scale about 500-2000 km. QUSES is performing a Quantum Key Distribution(QKD) experiment from satellite to ground station for testing of the global quantum secure communication network, and performing a Quantum Entanglement Distribution(QED) and Quantum Teleportation(QT) experiments with the purpose of testing the completeness of quantum mechanics theory at a sufficient spatial scale. The payload of QUSES is com posed of a Quantum Key Transceiver(QKT), a Quantum Entanglement Transmitter(QET), a Quantum Entangled-photon Source(QES), a Quantum Experiment Control Processor(QCP) and a Coherent laser Communication Terminator(CCT). This paper introduces the technical scheme of QUSES, including the requirement analysis, composi tion, technical innovation, on-orbit status and prospect of development for the future.展开更多
基金supported by the National Key R&D Program of China(No.2021YFA1501002)Thousand Talents Program for Distinguished Young Scholars.X.Li thanks the National Natural Science Foundation of China(No.22309021).
文摘Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.
基金National Natural Science Foundation of China(61375103,61533004,61320106012,and 61321002)the 863 Program of China(2014AA041602,2015AA042305 and 2015AA043202)+2 种基金the Key Technologies Research and Development Program(2015BAF13B01 and 2015BAK35B01)the Beijing Municipal Science and Technology Project(D161100003016002)the "111" Project under Grant B08043
文摘An indoor positioning method for robots is presented to improve the precision of displacement measurement using only low-cost inertial measurement units(IMUs).Firstly,a high-fidelity displacement estimation for linear motion is proposed.A new robot motion model is designed as well as an axis alignment that only uses a single axis of the accelerometer.The integral error of velocity is eliminated by a new subsection calculation method.Two complementary IMUs are combined by assigning them different weights to obtain high accuracy displacement results.Secondly,an orientation estimation based on a fusion filter for the steering motion is proposed.Experiments show that the proposed method significantly improves the accuracy of linear motion measurement and is effective for the indoor positioning of a robot.
文摘The Quantum Science Experiment Satellite(QUSES) is the first satellite deployed successfully in nearEarth space for quantum scientific experiments in the world, in which experimental study on the fundamental questions of quantum mechanics can be done under the condition of a spatial scale about 500-2000 km. QUSES is performing a Quantum Key Distribution(QKD) experiment from satellite to ground station for testing of the global quantum secure communication network, and performing a Quantum Entanglement Distribution(QED) and Quantum Teleportation(QT) experiments with the purpose of testing the completeness of quantum mechanics theory at a sufficient spatial scale. The payload of QUSES is com posed of a Quantum Key Transceiver(QKT), a Quantum Entanglement Transmitter(QET), a Quantum Entangled-photon Source(QES), a Quantum Experiment Control Processor(QCP) and a Coherent laser Communication Terminator(CCT). This paper introduces the technical scheme of QUSES, including the requirement analysis, composi tion, technical innovation, on-orbit status and prospect of development for the future.
