Based on the periodic oscillation of the stable acoustic cavitation bubble, we present a precise measure-ment technique for the bubble evolution. This technique comprises the lighting engineering of pulsing laser beam...Based on the periodic oscillation of the stable acoustic cavitation bubble, we present a precise measure-ment technique for the bubble evolution. This technique comprises the lighting engineering of pulsing laser beam whose phase can be digitally shifted, and the long distance microphotographics. We used a laser, an acousto-optic modulator, a pulse generator, and a long distance microscope. The evolution of a levitated bubble can be directly shown by a series of bubble’s images at different phases. Numerical simulation in the framework of the Rayleigh-Plesset bubble dynamics well supported the experimental result, and the ambient radius of the bubble, an important parameter re-lated to the mass of the gas inside the bubble, was obtained at the same time.展开更多
Simultaneous wireless information and power transfer(SWIPT)architecture is commonly applied in wireless sensors or Internet of Things(IoT)devices,providing both wireless power sources and communication channels.Howeve...Simultaneous wireless information and power transfer(SWIPT)architecture is commonly applied in wireless sensors or Internet of Things(IoT)devices,providing both wireless power sources and communication channels.However,the traditional SWIPT transmitter usually suffers from cross-talk distortion caused by the high peak-to-average power ratio of the input signal and the reduction of power amplifier efficiency.This paper proposes a SWIPT transmitting architecture based on an asynchronous space-time-coding digital metasurface(ASTCM).High-efficiency simultaneous transfer of information and power is achieved via energy distribution and information processing of the wireless monophonic signal reflected from the metasurface.We demonstrate the feasibility of the proposed method through theoretical derivations and experimental verification,which is therefore believed to have great potential in wireless communications and the IoT devices.展开更多
In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) wi...In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.10434070 and 10174036).
文摘Based on the periodic oscillation of the stable acoustic cavitation bubble, we present a precise measure-ment technique for the bubble evolution. This technique comprises the lighting engineering of pulsing laser beam whose phase can be digitally shifted, and the long distance microphotographics. We used a laser, an acousto-optic modulator, a pulse generator, and a long distance microscope. The evolution of a levitated bubble can be directly shown by a series of bubble’s images at different phases. Numerical simulation in the framework of the Rayleigh-Plesset bubble dynamics well supported the experimental result, and the ambient radius of the bubble, an important parameter re-lated to the mass of the gas inside the bubble, was obtained at the same time.
基金supported by the Program of Song Shan Laboratory(included in the management of Major Science and Technology Program of Henan Province)(Nos.221100211300-03 and 221100211300-02)the National Key Research and Development Program of China(No.2018YFA0701904)+5 种基金the National Natural Science Foundation of China(Nos.62288101,61731010,62201139,and U22A2001)the 111 Project(No.111-2-05)the Jiangsu Province Frontier Leading Technology Basic Research Project(No.BK20212002)the Fundamental Research Funds for the Central Universities(No.2242022k60003)the National Natural Science Foundation(NSFC)for Distinguished Young Scholars of China(No.62225108)the Southeast University-China Mobile Research Institute Joint Innovation Center(No.R207010101125D9).
文摘Simultaneous wireless information and power transfer(SWIPT)architecture is commonly applied in wireless sensors or Internet of Things(IoT)devices,providing both wireless power sources and communication channels.However,the traditional SWIPT transmitter usually suffers from cross-talk distortion caused by the high peak-to-average power ratio of the input signal and the reduction of power amplifier efficiency.This paper proposes a SWIPT transmitting architecture based on an asynchronous space-time-coding digital metasurface(ASTCM).High-efficiency simultaneous transfer of information and power is achieved via energy distribution and information processing of the wireless monophonic signal reflected from the metasurface.We demonstrate the feasibility of the proposed method through theoretical derivations and experimental verification,which is therefore believed to have great potential in wireless communications and the IoT devices.
基金Support to the SatNEx-Ⅲ Network of Experts (SatNEx-Ⅲ) CoO2,2011-2012
文摘In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates.
