The quantum entangled photon-pair source,as an essential component of optical quantum systems,holds great potential for applications such as quantum teleportation,quan-tum computing,and quantum imaging.The current wor...The quantum entangled photon-pair source,as an essential component of optical quantum systems,holds great potential for applications such as quantum teleportation,quan-tum computing,and quantum imaging.The current workhorse technique for preparing photon pairs involves performing spon-taneous parametric down conversion(SPDC)in bulk nonlinear crystals.However,the current power consumption and cost of preparing entangled photon-pair sources are relatively high,pos-ing challenges to their integration and scalability.In this paper,we propose a low-power system model for the quantum entan-gled photon-pair source based on SPDC theory and phase matching technology.This model allows us to analyze the per-formance of each module and the influence of component cha-racteristics on the overall system.In our experimental setup,we utilize a 5 mW laser diode and a typical type-II barium metabo-rate(BBO)crystal to prepare an entangled photon-pair source.The experimental results are in excellent agreement with the model,indicating a significant step towards achieving the goal of low-power and low-cost entangled photon-pair sources.This achievement not only contributes to the practical application of quantum entanglement lighting,but also paves the way for the widespread adoption of optical quantum systems in the future.展开更多
When the distribution of the sources cannot be estimated accurately, the ICA algorithms failed to separate the mixtures blindly. The generalized Gaussian model （GGM） is presented in ICA algorithm since it can model ...When the distribution of the sources cannot be estimated accurately, the ICA algorithms failed to separate the mixtures blindly. The generalized Gaussian model （GGM） is presented in ICA algorithm since it can model non- Ganssian statistical structure of different source signals easily. By inferring only one parameter, a wide class of statistical distributions can be characterized. By using maximum likelihood （ML） approach and natural gradient descent, the learning rules of blind source separation （BSS） based on GGM are presented. The experiment of the ship-radiated noise demonstrates that the GGM can model the distributions of the ship-radiated noise and sea noise efficiently, and the learning rules based on GGM gives more successful separation results after comparing it with several conventional methods such as high order cumnlants and Gaussian mixture density function.展开更多
Most of the near-field source localization methods are developed with the approximated signal model,because the phases of the received near-field signal are highly non-linear.Nevertheless,the approximated signal model...Most of the near-field source localization methods are developed with the approximated signal model,because the phases of the received near-field signal are highly non-linear.Nevertheless,the approximated signal model based methods suffer from model mismatch and performance degradation while the exact signal model based estimation methods usually involve parameter searching or multiple decomposition procedures.In this paper,a search-free near-field source localization method is proposed with the exact signal model.Firstly,the approximative estimates of the direction of arrival(DOA)and range are obtained by using the approximated signal model based method through parameter separation and polynomial rooting operations.Then,the approximative estimates are corrected with the exact signal model according to the exact expressions of phase difference in near-field observations.The proposed method avoids spectral searching and parameter pairing and has enhanced estimation performance.Numerical simulations are provided to demonstrate the effectiveness of the proposed method.展开更多
The development of 3D geological models involves the integration of large amounts of geological data,as well as additional accessible proprietary lithological, structural,geochemical,geophysical,and borehole data.Luan...The development of 3D geological models involves the integration of large amounts of geological data,as well as additional accessible proprietary lithological, structural,geochemical,geophysical,and borehole data.Luanchuan,the case study area,southwestern Henan Province,is an important molybdenum-tungsten -lead-zinc polymetallic belt in China.展开更多
【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征,【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础,选取代表性水文系列,结合入库污染负荷计算模型,构建了污染负荷量及入库强度的面源污染关...【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征,【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础,选取代表性水文系列,结合入库污染负荷计算模型,构建了污染负荷量及入库强度的面源污染关键源区识别技术流程,并在数据条件较为完备的沙河水库流域进行验证。【结果】结果表明:沙河水库流域总氮(Total Nitrogen,TN)入库负荷总量为198.34 t/a,面源污染占比为86.53%,流域内茶园TN负荷量贡献率最大,占比为23.84%;TN负荷量在丰水年和特丰水年比枯水年上升58.06%和289.09%,在年内丰水期TN月均负荷量比平水期和枯水期分别高出75.24%和372.51%;河道削减TN负荷量为33.58 t/a,削减比例为14.48%;子流域TN入库产污强度变化范围为0.36~4.73 t/km^(2)。面源污染排放入库低值区主要位于流域南部,高值区主要位于近库区域,沙河西和沙河东控制分区单位面积TN入库强度显著高于流域南部。【结论】针对高产污地类、高产污区域及高产污时段应提高面源污染防控力度;建立的技术流程可有效识别和科学解析流域面源污染关键源区,为流域水环境开展面源污染防治和生态适应性开发提供一定技术支持,使相关工作开展更加有的放矢。展开更多
文摘The quantum entangled photon-pair source,as an essential component of optical quantum systems,holds great potential for applications such as quantum teleportation,quan-tum computing,and quantum imaging.The current workhorse technique for preparing photon pairs involves performing spon-taneous parametric down conversion(SPDC)in bulk nonlinear crystals.However,the current power consumption and cost of preparing entangled photon-pair sources are relatively high,pos-ing challenges to their integration and scalability.In this paper,we propose a low-power system model for the quantum entan-gled photon-pair source based on SPDC theory and phase matching technology.This model allows us to analyze the per-formance of each module and the influence of component cha-racteristics on the overall system.In our experimental setup,we utilize a 5 mW laser diode and a typical type-II barium metabo-rate(BBO)crystal to prepare an entangled photon-pair source.The experimental results are in excellent agreement with the model,indicating a significant step towards achieving the goal of low-power and low-cost entangled photon-pair sources.This achievement not only contributes to the practical application of quantum entanglement lighting,but also paves the way for the widespread adoption of optical quantum systems in the future.
文摘When the distribution of the sources cannot be estimated accurately, the ICA algorithms failed to separate the mixtures blindly. The generalized Gaussian model （GGM） is presented in ICA algorithm since it can model non- Ganssian statistical structure of different source signals easily. By inferring only one parameter, a wide class of statistical distributions can be characterized. By using maximum likelihood （ML） approach and natural gradient descent, the learning rules of blind source separation （BSS） based on GGM are presented. The experiment of the ship-radiated noise demonstrates that the GGM can model the distributions of the ship-radiated noise and sea noise efficiently, and the learning rules based on GGM gives more successful separation results after comparing it with several conventional methods such as high order cumnlants and Gaussian mixture density function.
基金supported by the Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space(KF20202109)the National Natural Science Foundation of China(82004259)the Young Talent Training Project of Guangzhou University of Chinese Medicine(QNYC20190110).
文摘Most of the near-field source localization methods are developed with the approximated signal model,because the phases of the received near-field signal are highly non-linear.Nevertheless,the approximated signal model based methods suffer from model mismatch and performance degradation while the exact signal model based estimation methods usually involve parameter searching or multiple decomposition procedures.In this paper,a search-free near-field source localization method is proposed with the exact signal model.Firstly,the approximative estimates of the direction of arrival(DOA)and range are obtained by using the approximated signal model based method through parameter separation and polynomial rooting operations.Then,the approximative estimates are corrected with the exact signal model according to the exact expressions of phase difference in near-field observations.The proposed method avoids spectral searching and parameter pairing and has enhanced estimation performance.Numerical simulations are provided to demonstrate the effectiveness of the proposed method.
文摘The development of 3D geological models involves the integration of large amounts of geological data,as well as additional accessible proprietary lithological, structural,geochemical,geophysical,and borehole data.Luanchuan,the case study area,southwestern Henan Province,is an important molybdenum-tungsten -lead-zinc polymetallic belt in China.
文摘【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征,【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础,选取代表性水文系列,结合入库污染负荷计算模型,构建了污染负荷量及入库强度的面源污染关键源区识别技术流程,并在数据条件较为完备的沙河水库流域进行验证。【结果】结果表明:沙河水库流域总氮(Total Nitrogen,TN)入库负荷总量为198.34 t/a,面源污染占比为86.53%,流域内茶园TN负荷量贡献率最大,占比为23.84%;TN负荷量在丰水年和特丰水年比枯水年上升58.06%和289.09%,在年内丰水期TN月均负荷量比平水期和枯水期分别高出75.24%和372.51%;河道削减TN负荷量为33.58 t/a,削减比例为14.48%;子流域TN入库产污强度变化范围为0.36~4.73 t/km^(2)。面源污染排放入库低值区主要位于流域南部,高值区主要位于近库区域,沙河西和沙河东控制分区单位面积TN入库强度显著高于流域南部。【结论】针对高产污地类、高产污区域及高产污时段应提高面源污染防控力度;建立的技术流程可有效识别和科学解析流域面源污染关键源区,为流域水环境开展面源污染防治和生态适应性开发提供一定技术支持,使相关工作开展更加有的放矢。
