This paper addresses the problem of four-dimensional angle and Doppler frequency estimation for bistatic multiple-input multiple-output （MIMO） radar with arbitrary arrays in spatial co- lored noise. A novel method f...This paper addresses the problem of four-dimensional angle and Doppler frequency estimation for bistatic multiple-input multiple-output （MIMO） radar with arbitrary arrays in spatial co- lored noise. A novel method for joint estimation of Doppler fre- quency, two-dimensional （2D） direction of departure and 2D direc- tion of arrival based on the propagator method （PM） for arbitrary arrays is discussed. A special matrix is constructed to eliminate the influence of spatial colored noise. The four-dimensional （4D） angle and Doppler frequency are extracted from the matrix and the three- dimensional （3D） coordinates of the targets are then calculated on the basis of these angles. The proposed algorithm provides a lower computational complexity and has a parameter estimation very close to that of the ESPRIT algorithm and the DOA-matrix al- gorithm in the high signal to noise ratio and the Cramer-Rao bound （CRB） is given. Furthermore, multi-dimensional parameters can be automatically paired by this algorithm to avoid performance degra- dation resulting from wrong pairing. Simulation results demonstrate the effectiveness of the proposed method.展开更多
Based on the origin and development of landscape urbanism,with several representative cases,this paper introduces the origin of ecological urbanism,as well as the main concepts and strategies,and then compared the cha...Based on the origin and development of landscape urbanism,with several representative cases,this paper introduces the origin of ecological urbanism,as well as the main concepts and strategies,and then compared the changes from Landscape Urbanism to Ecological Urbanism.At last,this paper discusses its enlightenment on China’s urban construction and landscape development with the focus on the actual situation in China.展开更多
The anomalous Hall effect(AHE)that associated with the Berry curvature of occupied electronic states in momentum-space is one of the intriguing aspects in condensed matter physics,and provides an alternative for poten...The anomalous Hall effect(AHE)that associated with the Berry curvature of occupied electronic states in momentum-space is one of the intriguing aspects in condensed matter physics,and provides an alternative for potential applications in topological electronics.Previous experiments reported the tunable Berry curvature and the resulting magnetization switching process in the AHE based on strain engineering or chemical doping.However,the AHE modulation by these strategies are usually irreversible,making it difficult to realize switchable control of the AHE and the resultant spintronic applications.Here,we demonstrated the switchable control of the Berry-curvature-related AHE by electrical gating in itinerant ferromagnetic Cr_(7)Te_(8)with excellent ambient stability.The gate-tunable sign reversal of the AHE can be attributed to the redistribution of the Berry curvature in the band structure of Cr_(7)Te_(8)due to the intercalation-induced change in the Fermi level.Our work facilitates the applications of magnetic switchable devices based on gate-tunable Berry curvature.展开更多
In this paper a label-free fluorescent sensor for probing the interaction between heparin and protein was reported.Heparin,the bioactive polyanions,formed supramolecular assemblies with cationic surfactant cetyltrimet...In this paper a label-free fluorescent sensor for probing the interaction between heparin and protein was reported.Heparin,the bioactive polyanions,formed supramolecular assemblies with cationic surfactant cetyltrimethyl ammonium bromide (CTAB).The environment-dependent dye pyrene,encapsulated in hydrophobic interiors of the supramolecular assemblies worked as the fluorescence probe.Once the heparin-binding protein was added,competing interactions of protein with heparin would weaken the interaction between CTAB and heparin.As a result,the noncovalently sequestered pyrene would be released upon disassembly and the fluorescence of the released pyrene was subsequently decreased.The binding events were exemplified by protamine and Tat peptide,these processes were also verified by DLS and TEM.Such a strategy is appealing as organic synthesis was traded off against supramolecular assembly.This label-free fluorescent system is simple,selective,convenient,and can serve as a good complement to other existing methods,also this method has the potential for preprimary drug screening.展开更多
基金supported by the National Natural Science Foundation of China(6137116961179006)+1 种基金the Jiangsu Postdoctoral Research Funding Plan(1301013B)the Nanjing University of Aeronautics and Astronautics Funding(NZ2013208)
文摘This paper addresses the problem of four-dimensional angle and Doppler frequency estimation for bistatic multiple-input multiple-output （MIMO） radar with arbitrary arrays in spatial co- lored noise. A novel method for joint estimation of Doppler fre- quency, two-dimensional （2D） direction of departure and 2D direc- tion of arrival based on the propagator method （PM） for arbitrary arrays is discussed. A special matrix is constructed to eliminate the influence of spatial colored noise. The four-dimensional （4D） angle and Doppler frequency are extracted from the matrix and the three- dimensional （3D） coordinates of the targets are then calculated on the basis of these angles. The proposed algorithm provides a lower computational complexity and has a parameter estimation very close to that of the ESPRIT algorithm and the DOA-matrix al- gorithm in the high signal to noise ratio and the Cramer-Rao bound （CRB） is given. Furthermore, multi-dimensional parameters can be automatically paired by this algorithm to avoid performance degra- dation resulting from wrong pairing. Simulation results demonstrate the effectiveness of the proposed method.
文摘Based on the origin and development of landscape urbanism,with several representative cases,this paper introduces the origin of ecological urbanism,as well as the main concepts and strategies,and then compared the changes from Landscape Urbanism to Ecological Urbanism.At last,this paper discusses its enlightenment on China’s urban construction and landscape development with the focus on the actual situation in China.
基金National Natural Science Foundation of China,Grant/Award Numbers:92365203,52072168,51861145201,12204232,52302180,92064005National Key Research and Development Program of China,Grant/Award Numbers:2021YFA1601004,2021YFA1202901。
文摘The anomalous Hall effect(AHE)that associated with the Berry curvature of occupied electronic states in momentum-space is one of the intriguing aspects in condensed matter physics,and provides an alternative for potential applications in topological electronics.Previous experiments reported the tunable Berry curvature and the resulting magnetization switching process in the AHE based on strain engineering or chemical doping.However,the AHE modulation by these strategies are usually irreversible,making it difficult to realize switchable control of the AHE and the resultant spintronic applications.Here,we demonstrated the switchable control of the Berry-curvature-related AHE by electrical gating in itinerant ferromagnetic Cr_(7)Te_(8)with excellent ambient stability.The gate-tunable sign reversal of the AHE can be attributed to the redistribution of the Berry curvature in the band structure of Cr_(7)Te_(8)due to the intercalation-induced change in the Fermi level.Our work facilitates the applications of magnetic switchable devices based on gate-tunable Berry curvature.
基金Financial support from the Natural Science Foundation of China (Nos.50830106,21174126),the China National Funds for Distinguished Young Scientists (No.51025312) and the Open Project of State Key Laboratory of Supramolecular Structure and Materials (No.sklssm201316) is gratefully acknowledged.
文摘In this paper a label-free fluorescent sensor for probing the interaction between heparin and protein was reported.Heparin,the bioactive polyanions,formed supramolecular assemblies with cationic surfactant cetyltrimethyl ammonium bromide (CTAB).The environment-dependent dye pyrene,encapsulated in hydrophobic interiors of the supramolecular assemblies worked as the fluorescence probe.Once the heparin-binding protein was added,competing interactions of protein with heparin would weaken the interaction between CTAB and heparin.As a result,the noncovalently sequestered pyrene would be released upon disassembly and the fluorescence of the released pyrene was subsequently decreased.The binding events were exemplified by protamine and Tat peptide,these processes were also verified by DLS and TEM.Such a strategy is appealing as organic synthesis was traded off against supramolecular assembly.This label-free fluorescent system is simple,selective,convenient,and can serve as a good complement to other existing methods,also this method has the potential for preprimary drug screening.
