This paper presents a synthetic aperture radar (SAR) system and processing algorithm for automotive applications using short range vehicle-mounted Frequency Modulation Continuous Wave (FMCW) radar. Aiming at real-time high resolution vehicle-borne SAR imaging, the combines advantages of accurate focusing wavenumber domain algorithms with precision motion compensation by utilizing only knowledge vehicle's velocity angular velocity. We present measurement results collected during various...

ABSTRACT Fatigue performance of reinforced concrete (RC) components strengthened with fibre polymer (FRP) is largely improved. However, temperature changes service environment have a great effect on the fatigue behaviour RC FRP. Concerning about variations in subtropical areas such as South China, this paper analyses beams carbon laminate (CFL) from experimental studies and theoretical analysis under four different temperatures (5 °C, 20 50 80 °C) five stress levels (0.60, 0.66, 0.72, 0.78,...

To improve the understanding of optical image resolution transmission-mode GaAs photocathode, by establishing surface scattering analysis model AlGaAs window layer, we have researched effect height distribution variance σ on transfer function (STF) and point spread (PSF) photocathode. The simulation results show that decrease is beneficial to resolution. This improvement mainly attributed in input light energy attenuation spatial diffusion caused smaller σ, thus signal noise ratio degraded increased.

The embedding-based speaker verification (SV) technology has witnessed significant progress due to the advances of deep convolutional neural networks (DCNN). However, how improve discrimination embedding in open world SV task is still focus current research community. In this paper, we discriminative power from three-fold: (1) NeXtVLAD introduced aggregate frame-level features, which decomposes high-dimensional features into a group low-dimensional vectors before applying VLAD aggregation....

An infrared perfect absorber structure is designed based on GaAs/Au/SiO2 metamaterial with numerical simulation, in which gold split ring resonators (SRR) embedded the GaAs layer. The absorption exceeds 99% at 1360 nm under plane wave excitation its polarization perpendicular to opening direction of SRR. When parallel direction, 97% and 56% 970 2070 nm, respectively, realize dual-band absorption. peaks are effectively modulated by controlling surface current density distribution resonant...

Ultrashort multi-ke V x-ray pulses are generated by electron plasma produced the irradiation of femtosecond on metals. These sub-picosecond have extended field spectroscopy into time domain. However, pulse-to-pulse instability and long data acquisition restrict application ultrashort systems operating at low repetition rates. Here we report performance a laser plasma-induced hard source that operates 1-k Hz rate, provides flux 2.0 × 1010 photons/s Cu Kαradiation. Using this system for...

In the preparation process of negative electron affinity GaAs photocathodes, p-type doped property is beneficial to photoemission, and doping element usually Be or Zn. fact, C-doped material has been widely used due its high activation rate, extremely low diffusion coefficient, good thermal stability, whereas influence mechanism C dopant on performance photocathode still unclear. order investigate substitutional effect GaAs, electronic structures optical properties along with angular...

Due to the excellent quantum conversion and spectral response characteristics of AlGaN photocathode, it has become most promising III-V group semiconductor photocathode in solar-blind signal photoconversion devices ultraviolet band. Herein, influence factors time-resolved are researched by solving photoelectron continuity equation flow density equation, such as AlN/AlGaN interface recombination rate, electron diffusion coefficient, activation layer thickness. The results show that time...

The AlGaN photocathode with a superlattice emission layer was grown by metal organic chemical vapor deposition. existence of the structure confirmed using transmission electron microscope, and its optical electrical properties were measured. results showed that introduction can reduce transmittance reflectance at 275 nm improve absorption incident light. In particular, Hall measurement indicate significantly increase concentration holes in material. activation experiment demonstrated...

Peeling along the interface between FRP and concrete under fatigue load is common failure pattern for RC structures strengthened with FRP. In this paper, five groups specimens were subjected to study mechanism bonding carbon fiber laminate (CFL) concrete. The Δσ~N curves derived from experiments, laws of strains slip on analyzed in paper.

In this work, the compression behaviour of Xinjiang poplar column was reinforced by basalt fibre polymer (BFRP) strips with different configurations, and thenumerical simulations were performed on axial eccentric compressions columns unreinforced BFRP to assess effect bearing capacity deformation columns. The results show that use reinforce effectively improves its compressive (axial compression) andbending (eccentric compression), at same time, stiffness strengthened increased bonding area BFRP.

Steel fiber reinforced polymer high strength structural concrete (SPHSC) is a new composite material which used in long-span bridge structures invented by this research team. Based on the material, experiments of stress-strain full curves under uniaxial compression were carried out. The achieved from simple improved method. By method theoretical derivation and experimental data fitting, constitutive equation SPHSC contains only two undetermined parameters compressive parameter steel was...

Ground-based space target pulse measurement radar searches and captures medium-and high-orbit targets, there are some problems in radial range measurement, such as ambiguity low echo signal-to-noise ratio. In order to solve the above problems, a coherent accumulation deblurring method based on pseudo code phase modulation is proposed. This makes full use of good autocorrelation m-sequence. Firstly, transmitted modulated by m-sequence pseudo-code, then collected signal compensated pseudo-code...

C-doped GaAs is considered a potential material for negative electron affinity photocathodes, where the p-type doped property beneficial to photoemission. To clarify stability and efficiency during Cs/O activation, gradient concentration of Cs adsorption co-adsorption models are established. The work function, energy, surface dipole moment intensified by first principles calculation based on density functional theory. Experimental results demonstrate that activation effectively enhances...

To enhance the spatial resolution capability of transmission-mode NEA GaAs photocathodes, this study employed a white-light interferometer to measure surface configurations photocathode components post thermal compression bonding. Precise fitting was achieved using Zernike polynomials, successfully deriving polynomial coefficients. Further, these calculated results were integrated into optical design software for modeling, aiming elucidate relationship between photocathode's transfer...

Expanded target data association algorithm for wideband radar is researched. A mixed proposed which mix high resolution range profile (HRRP) feature aided with traditional joint probability (JPDA) algorithm. It indicates that the can combine advantages of two algorithms and insure validity association.

To discover the fatigue behavior and durability of new type fiber concrete named “steel reinforced polymer high strength (SFPHC)”, considering climatic conditions in Guangdong Province, using research method theoretical analysis combined with experimental study, thermal SFPHC used bridge superstructure three different temperatures (20°C，50°C，80°C) is discussed compared C60 which has similar static mechanical properties at room temperature. The results show that performance can be described...