Search

Previous research has demonstrated that distorted images caused by turbid media can be reconstructed by turbid lens imaging (TLI) method. In this way, it’s critical to accurately obtain the transmission matrix (TM) of turbid media. In this letter, we propose an improved method which is still based on Hilbert transform to get the transmission matrices, but it will use four images for each transmission matrix element to eliminate the influence of speckle intensity variation. In addition, a Hanning window filter is introduced to reduce the white Gaussian noise of original images to improve the result of TLI method. [ABSTRACT FROM AUTHOR]

Comparisons were made among the evaluation models of fatigue crack growth in various codes, standards, and guidelines, to illustrate the significance of transition point in accuracy. A new bilinear model was established with transition point and fatigue threshold fully considered, and was found more accurate than existing codes and standards for evaluation of fatigue crack growth behavior in both Paris and near-threshold regimes. • Conservativeness in existing codes and standards for fatigue crack growth assessment was compared. • Transition point in fatigue crack growth was found significant in assessment accuracy. • A new bilinear model for fatigue crack growth evaluation was developed. [ABSTRACT FROM AUTHOR]

• m -ln C relationship was correlated well with transition behavior of FCG curve. • A master curve for transition behavior of FCG curve was found. • Crack closure was considered for transition point modeling for the first time. • A new model for transition point prediction was established. The transition behavior of fatigue crack growth was investigated using data from a CrNiMoV steel welded joint. The m -ln C was linearly correlated under a given stress ratio in both Paris and near-threshold regimes, where the coordinate of transition point was found as slope and intercept of m -ln C relationship. All m -ln C curves tended to pass through one fixed point, (m 0 , lnC 0), and a master curve for transition point was determined. A new model for transition point prediction was established which had significance in accurate fatigue life assessment on the basis of the bilinear approach. [ABSTRACT FROM AUTHOR]

Selenization is a key process to prepare Cu 2 ZnSnS x Se 4-x (CZTSSe) thin films from sulfide for high efficient solar cell. To explore the effect of annealing atmosphere on the substitution of S by Se in Cu 2 ZnSnS 4 (CZTS) thin films, different selenization atmosphere (Vacuum or Ar) are used. By examining the annealed sample, it is found that selenization under Ar atmosphere replaces S with Se more efficiently, resulting large grain and small band-gap. The reaction kinetics has been studied to explore such phenomena. It demonstrates that the substitution reaction is enhanced when the flowing Ar carries off S gas. Finally, the effect of annealing atmosphere on oxide-based CZTSSe devices has also been studied. The Vacuum selenized CZTSSe device shows a higher efficiency of 4.4%, due to the more appropriate band-gap. To the best of our knowledge, this is the best device performance in oxides nanoparticles-derived CZTSSe solar cell. [ABSTRACT FROM AUTHOR]

The inhomogeneity distribution of applied magnetic field along longitudinal direction above permanent magnetic guideway (PMG) reduces the levitation stability of the high- T c superconductor (HTS) maglev system. In order to explore and reveal the inhomogeneity distribution of magnetic field along longitudinal direction above PMG and its causes, as well as its influence on the static levitation force of YBa 2 Cu 3 O 7- x (YBCO) bulk, the theoretical model is built by COMSOL Multiphysics to simulate the longitudinal distribution of magnetic field above the PMG and the static levitation force of the YBCO bulk. Furthermore, a three-axis motion experimental platform is designed and built to measure the longitudinal distribution of magnetic field, upper surface profile of the PMG and static levitation force of the YBCO bulk by the corresponding testing equipment. It is shown in this study that, in the assembly processing of PMG, the surface of permanent magnet (PM) is sloping along the longitudinal direction, and there are gaps and damage between adjacent PMs. The simulation and experimental results show that these multiple defects lead to inhomogeneity distribution of magnetic field along the longitudinal direction and the attenuation at the joints, resulting in the difference in the static levitation force of YBCO bulk at different longitudinal positions of the PMG. The results could provide a reference for the further design and practical application of higher performance PMG. [ABSTRACT FROM AUTHOR]