[en] The structure of the wide resonance θ(1720) produced in J/ψ hadronic decays is studied by using the generalized moment analysis. Since the production ratio of the f'₂(1525) is very small in the process J/ψ → ωθ(1720) we may neglect the influence of the f'₂(1525). Whereas the production ratio of the f'₂(1525) is larger in the process J/ψ → ψθ(1720), we must consider the coherence effects of the f'₂(1525). From the studies of the two processes and the corresponding J/ψ radiative decay we are able to understand the structure of the wide resonance θ(1720) better

[en] The structure of the wide resonance θ(1720) produced in J/ψ radiative decay is studied by using moment analysis. Since the f₂^'(1525) and θ(1720) resonances overlap in this mass region, two three-states coupling structure modes 2⁺⁺(f₂^'(1525)) + 0⁺⁺ + 0⁺⁺ and 2⁺⁺(f₂^'(1525)) + 0⁺⁺ + 2⁺⁺ are discussed. It is helpful to make clear the structure of the wide resonance θ(1720), and to determine masses, widths, spins and other important properties of the two resonance states, for example G(1590) and f₂(1720),in order to understand the two interesting states better

[en] The difficulty in infrared and radar fusion target detection lies in the pre-processing steps such as sample reduction and feature reduction of heterogeneous sensors. For the problem of data volume redundancy, HVS sample reduction is proposed to reduce the amount of data in the infrared data set. Infrared and radar joint feature vectors are constructed through nearest neighbor data association. For the problem of feature redundancy, a weighted mutual information feature selection method based on prior information is proposed according to the difference of feature sources. The fusion data set is then used for classification. The experiments show that the HVS-based sample reduction and the prior weighted feature selection achieved a higher detection probability and a shorter detection time, and improved the robustness in the case of large differences between the training set and the test set.

[en] In the infrared small target detection, the clutter formed by buildings, trees and protruding clouds is densely distributed and difficult to filter out. The hysteresis threshold detection algorithm utilizes the geometric features of small target to reduce false alarms. Images are filtered in multiple scales, the location and scale of the points of interest are extracted by non-maximum suppression. To determine the connection state of the focus and clutter, local gradient second-order origin moment is proposed to eliminate strong edges. The hysteresis threshold segmentation is performed to exclude stubborn false alarms and detect small targets. Experiments show that the proposed algorithm has a significant effect in removing false alarms, and achieves both the high detection probability and low false alarm probability.

[en] Fourier single-pixel imaging (FSI) has been proven capable of acquiring excellent image quality when is sampled the fully information in Fourier domain. However, when the sampling measurements is limited, image reconstruction by applying inverse Fourier transform algorithm would result in the severe ringing effect and the loss of image details. In this report, we propose a new algorithm for FSI reconstruction based on compressed sensing theory, which utilizes joint discrete gradient and non-local self-similarity priors, thus substantially using the prior knowledge of natural images in reconstruction process. Both the results of computational simulations and experiments demonstrate the efficacy of the proposed algorithm.

[en] The distributions of the pseudorapidity gap length between two particles, which included (K-1) particles between them, and many-particle pseudorapidity correlation functions have been calculated by using the experimental data of the charged particles pseudorapidity distributions produced in 400 GeV/c pp collisions. The Monte Carlo simulations for the experimental data have been made based on a cluster model. The average cluster size has been estimated

[en] Gradient ghost imaging (GGI) is a new imaging method that can directly extract the edge of a target from the correlation of light intensity fluctuations. However, there are problems of poor image quality and practicability in GGI. The corner point is an important target feature and has important applications in the fields of image processing and machine vision. In this paper, we propose a corner detection scheme that combines a corner detection algorithm based on curvature scale space with a GGI system, which can directly extract corner points from the reconstruction results of ghost imaging. A simulation and experimental results show that our method can acquire precise and robust corner information of an unknown target in undersampled cases, which promotes the practical development of ghost imaging. (paper)

[en] Chiral liquid crystal polymers (CLCPs) with spontaneous ordered structure, unique optical properties and high flexibility are promising smart materials. However, their broad application is inevitably limited by the single attribute of chiral mesophase in the cases of fabricating functional materials with multiple attributes. In this work, a novel and effective method of modifying CLCPs by charged two-dimensional (2D) zirconium phosphate (ZrP) nanoplatelets is established. ZrP nanoplatelets can be incorporated into the matrix of CLCPs by the host-guest effect. The dispersed ZrP nanoplatelets can increase the glass transition temperature due to the steric hindrance. The incorporation of ZrP nanoplatelets can increase the thermal decomposition temperature of CLCPs from 274.2 °C to 316.9 °C when the ZrP content ranging from 0 wt% to 20 wt%. The CLCP-ZrP nanocomposites exhibit typical thermochromism in the visible light region in response to temperature. The intercalation of ZrP nanoplatelets can tune the wettability of CLCPs from hydrophobicity to hydrophilicity, the contact angles are within the range from 26.25° to 110.0°. We believe the modification of CLCPs by ZrP nanoplatelets paves the way to functionalize polymer matrix by a variety of novel 2D materials, such as black phosphorus, MXenes and transition-metal dichalcogenides, and to fabricate multifunctional nanocomposites. (paper)

[en] Highlights: • LED cooling by thermoelectric cooler integrated microchannel heat sink is proposed. • The relative importance of the factors was revealed by the Taguchi method. • The proposed LED + TEC + WMHS device showed excellent cooling performance. • The LED headlight can be cooled to temperature lower than the coolant temperature. • Cooling system and factor levels for different applications were recommended. -- Abstract: Effective thermal management is crucial for light-emitting diodes (LED). Thermoelectric cooler (TEC) and microchannel heat sink (MHS) have been demonstrated to be effective for thermal management of LED. However, neither the combination of these two methods, nor the dominant factors which could be effectively adjusted to control the LED temperature, have been reported. In this study, a cooling device integrating TEC and water-cooled microchannel heat sink (WMHS) is proposed to improve the thermal management of high-power LED headlights. The start-up performance of the proposed device, LED + TEC + WMHS, was evaluated and compared with three different systems, namely LED + WMHS, LED + AHS (air-cooled heat sink), and LED + TEC + AHS. Experimental results have demonstrated the best performance of the LED + TEC + WMHS device. Orthogonal experiments based on the Taguchi method were conducted to reveal dominant factors among four variables, including TEC current, water inlet temperature, water flow velocity, and ambient temperature. The results show that effects of all the factors were significant while the TEC current has most important influence on the performance. The variation of the thermal management performance with the levels of the factors were investigated. The LED temperature was only 60.0 °C even at severe working conditions (T_a = 80 °C, T_i = 55 °C) and moderate cooling input (I_TEC = 2 A, u = 0.49 m/s), indicating great thermal management performance of the proposed method. Choosing a cooling system and adjusting the factor levels for different applications were recommended.

[en] The ability to control the dynamics of self-assembly of anisotropic nanoparticles over multiple length scales by application of external fields is an important technological and fundamental challenge in colloidal science and soft condensed matter physics. Here we demonstrate the controlled assembly of two-dimensional (2D) colloidal liquid crystals under the influence of gravity and an external magnetic field. Due to the positive anisotropy of diamagnetic susceptibility (▵χ  >  0), the colloidal nanoplates of monolayer zirconium phosphate could exhibit intriguing alignment with their normals parallel to the magnetic field, thus transforming the multi-domain nematic phase into a mono-domain superstructure. Interestingly, the quasi-equilibrium states of such 2D soft materials under the prolonged gravity-induced sedimentation were found to generate a rich pattern of interference color bands (referred to as rainbows in a vial) upon under the effect of an aligning magnetic field. The birefringence measurement of the resulting color bands suggested quadratically decreasing volume fraction with sample height. The osmotic pressure (П) as a function of nanoplate volume fraction (ϕ) is found to agree with the theoretical prediction of the equation of state of the nematic phase of hard nanoplates, with a positive deviation at higher volume fractions. To the best of our knowledge, such field-driven dynamic formation of rich interference color bands, imitating almost the full spectrum of Michel-Levy interference bands, which was a pure mathematical representation, is experimentally achieved for the first time in a single sample. (paper)