Produced by the Beijing Taidu Automobile Safety Equipment Manufacture Co. Ltd., the Taidu electronic anti-theft alarm system has a single key system and easy operation. The system has a cover to protect it from accide...Produced by the Beijing Taidu Automobile Safety Equipment Manufacture Co. Ltd., the Taidu electronic anti-theft alarm system has a single key system and easy operation. The system has a cover to protect it from accidental triggering. Indicators display its remote control function, controlling all the locking and unlocking actions for an automobile’s doors within a range of 50 metres. The system has a展开更多
Two-dimensional（2D） topological insulators（TTs,or quantum spin Hall insulators） are special insulators that possess bulk 2D electronic energy gap and time-reversal symmetry protected one-dimensional（1D） edge sta...Two-dimensional（2D） topological insulators（TTs,or quantum spin Hall insulators） are special insulators that possess bulk 2D electronic energy gap and time-reversal symmetry protected one-dimensional（1D） edge state.Carriers in the edge state have the property of spin-momentum locking,enabling dissipation-free conduction along the 1D edge.The existence of 2D TIs was confirmed by experiments in semiconductor quantum wells.However,the 2D bulk gaps in those quantum wells are extremely small,greatly limiting potential application in future electronics and spintronics.Despite this limitation,2D TIs with a large bulk gap attracted plenty of interest.In this paper,recent progress in searching for TIs with a large bulk gap is reviewed briefly.We start by introducing some theoretical predictions of these new materials and then discuss some recent important achievements in crystal growth and characterization.展开更多
A low-noise photodetector is a basic tool for the research of quantum information processing. We present a specially designed low-noise photoelectric detector with a bandwidth of 130 MHz, using a transimpedance amplif...A low-noise photodetector is a basic tool for the research of quantum information processing. We present a specially designed low-noise photoelectric detector with a bandwidth of 130 MHz, using a transimpedance amplification circuit. Based on the detailed calculation of the dependence on each parameter of the detector,a useful method of how to design a low-noise and broadband photodetector is provided. When the optical power is between 1.0 and 16 m W, the photodetector has a good linear response to the injected light. Its electronics noise power is below-77 d Bm, which is within the whole bandwidth. When the incident light power is 2 m W, the output noise powers are 10.0, 8.0, and 6.0 d B higher than the corresponding electronics noise within the bandwidth of 1–50, 50–90, and 90–130 MHz, respectively, which is in good agreement with the theoretical prediction.Thus, this photoelectric detector could have good application prospects in quantum communication and an optical cavity locking system.展开更多
文摘Produced by the Beijing Taidu Automobile Safety Equipment Manufacture Co. Ltd., the Taidu electronic anti-theft alarm system has a single key system and easy operation. The system has a cover to protect it from accidental triggering. Indicators display its remote control function, controlling all the locking and unlocking actions for an automobile’s doors within a range of 50 metres. The system has a
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1632272,11574201,and 11521404)support from the Changjiang Scholars Program,Chinathe Program for Professor of Special Appointment(Eastern Scholar),China
文摘Two-dimensional（2D） topological insulators（TTs,or quantum spin Hall insulators） are special insulators that possess bulk 2D electronic energy gap and time-reversal symmetry protected one-dimensional（1D） edge state.Carriers in the edge state have the property of spin-momentum locking,enabling dissipation-free conduction along the 1D edge.The existence of 2D TIs was confirmed by experiments in semiconductor quantum wells.However,the 2D bulk gaps in those quantum wells are extremely small,greatly limiting potential application in future electronics and spintronics.Despite this limitation,2D TIs with a large bulk gap attracted plenty of interest.In this paper,recent progress in searching for TIs with a large bulk gap is reviewed briefly.We start by introducing some theoretical predictions of these new materials and then discuss some recent important achievements in crystal growth and characterization.
基金supported by the Key Project of the Ministry of Science and Technology of China(No.2016YFA0301402)the Natural Science Foundation of China(Nos.11322440,11474190,and 11304190)+1 种基金the FOK YING TUNG Education Foundation,Natural Science Foundation of Shanxi Province(No.2014021001)the Program for Sanjin Scholars of Shanxi Province
文摘A low-noise photodetector is a basic tool for the research of quantum information processing. We present a specially designed low-noise photoelectric detector with a bandwidth of 130 MHz, using a transimpedance amplification circuit. Based on the detailed calculation of the dependence on each parameter of the detector,a useful method of how to design a low-noise and broadband photodetector is provided. When the optical power is between 1.0 and 16 m W, the photodetector has a good linear response to the injected light. Its electronics noise power is below-77 d Bm, which is within the whole bandwidth. When the incident light power is 2 m W, the output noise powers are 10.0, 8.0, and 6.0 d B higher than the corresponding electronics noise within the bandwidth of 1–50, 50–90, and 90–130 MHz, respectively, which is in good agreement with the theoretical prediction.Thus, this photoelectric detector could have good application prospects in quantum communication and an optical cavity locking system.
