Dynamic X-ray speckle-tracking imaging with high-accuracy phase retrieval based on deep learning.

Speckle-tracking X-ray imaging is an attractive candidate for dynamic X-ray imaging owing to its flexible setup and simultaneous yields of phase, transmission and scattering images. However, traditional speckle-tracking imaging methods suffer from phase distortion at locations with abrupt changes in density, which is always the case for real samples, limiting the applications of the speckle-tracking X-ray imaging method. In this paper, we report a deep-learning based method which can achieve dynamic X-ray speckle-tracking imaging with high-accuracy phase retrieval. The calibration results of a phantom show that the profile of the retrieved phase is highly consistent with the theoretical one. Experiments of polyurethane foaming demonstrated that the proposed method revealed the evolution of the complicated microstructure of the bubbles accurately. The proposed method is a promising solution for dynamic X-ray imaging with high-accuracy phase retrieval, and has extensive applications in metrology and quantitative analysis of dynamics in material science, physics, chemistry and biomedicine.

Taurine as a powerful passivator of perovskite layer for efficient and stable perovskite solar cells.

Due to the ionic lattice property and the solution manufacture process of the perovskite light absorbing layer, there are several intrinsic defects (such as vacancies and low coordination Pb2+ and I-) in perovskite films, which cause undesired photon-generated carrier recombination in the perovskite solar cells (PSCs) and seriously affect the power conversion efficiency (PCE) of devices. Defect passivation strategy is one of the most effective ways to eliminate the defects in perovskite films. Herein, a multifunctional Taurine molecule was introduced into CH3NH3PbI3 (MAPbI3) perovskite precursor solution to passivate the defects. It was found that Taurine with sulfonic acid (-SOOOH) and amino (-NH2) groups can bind with uncoordinated Pb2+ and I- ions, respectively, which can significantly reduce the defect density and suppress the carrier non-radiative recombination. Under atmospheric environment, non-hole transport layer FTO/TiO2/perovskite/carbon structure PSCs were prepared. The device with Taurine showed a PCE of 13.19%, which is 17.14% higher than that of the control device (11.26%). With the suppressed defects, the Taurine passivated devices also showed enhanced device stability. The unencapsulated Taurine passivated device stored in ambient air after 720 h (temp. ∼25 °C and RH ∼25%) maintained 58.74% original PCE, while that of the control device was only about 33.98%.

Real-time X-ray imaging of mouse cerebral microvessels in vivo using a pixel temporal averaging method.

Rodents are used extensively as animal models for the preclinical investigation of microvascular-related diseases. However, motion artifacts in currently available imaging methods preclude real-time observation of microvessels in vivo. In this paper, a pixel temporal averaging (PTA) method that enables real-time imaging of microvessels in the mouse brain in vivo is described. Experiments using live mice demonstrated that PTA efficiently eliminated motion artifacts and random noise, resulting in significant improvements in contrast-to-noise ratio. The time needed for image reconstruction using PTA with a normal computer was 250 ms, highlighting the capability of the PTA method for real-time angiography. In addition, experiments with less than one-quarter of photon flux in conventional angiography verified that motion artifacts and random noise were suppressed and microvessels were successfully identified using PTA, whereas conventional temporal subtraction and averaging methods were ineffective. Experiments performed with an X-ray tube verified that the PTA method could also be successfully applied to microvessel imaging of the mouse brain using a laboratory X-ray source. In conclusion, the proposed PTA method may facilitate the real-time investigation of cerebral microvascular-related diseases using small animal models.

Enhanced adsorption of sulfonamides by a novel carboxymethyl cellulose and chitosan-based composite with sulfonated graphene oxide.

A novel multiple active sites sponge was fabricated from carboxymethyl cellulose (CMC) and genipin crosslinked carboxyalkyl-chitosan (GCC) combined with sulfonated graphene oxide (CMC/SGO-GCC) and used as a material for adsorbing sulfonamide antibiotics. The GO contains a variety of carboxyl and hydroxyl groups, which can interact with the hydroxyl groups of chitosan and CMC to form strong hydrogen bonds. This adsorption process is spontaneous and pH dependent, and shows high sulfamethoxazole (SMX) and sulfapyridine (SPD). Removal efficiency from aqueous solutions. Equilibrium adsorption studies showed that the maximum adsorption capacities of SMX and SPD decreased from 312.28 to 272.83 mg/g and 161.89 to 146.56 mg/g, respectively, as the temperature increased from 298 to 318 K. Reusability experiments indicated that CMC/SGO-GCC maintained a high adsorption capacity for SMX and SPD upon its reuse. This study shows that CMC/SGO-GCC is an ideal material for adsorbing SMX and SPD.

High-precision speckle-tracking X-ray imaging with adaptive subset size choices.

Speckle-tracking imaging has the advantages of simple setup and high-sensitivity to slowly varying phase gradients. Subset size choice is regarded as a trade-off problem for speckle-tracking X-ray imaging where one needs to balance the spatial resolution and accuracy, where the subset was defined as the region of interest of windowing choice for digital image correlation algorithm. An adaptive subset size choice method based on a Fourier transform for effectively detecting sample phase information without foreknowledge of the sample structure is presented in this study. The speckle-tracking phase-contrast and the form of dark-field imaging based on this method have the advantages of (i) high resolution and time saving compared to large subset choice and (ii) partially improvement the influence from experimental noises, background fluctuations, and false signals compared to small subset choice at the same time. This method has proven to be particularly robust in the experimental condition of poor signal-to-noise ratio. The proposed method may be expanded to all speckle-based imaging methods and other imaging techniques based on the subset or window matching.

Comprehensive characterization of TSV etching performance with phase-contrast X-ray microtomography.

Comprehensive evaluation of through-silicon via (TSV) reliability often requires deterministic and 3D descriptions of local morphological and statistical features of via formation with the Bosch process. Here, a highly sensitive phase-contrast X-ray microtomography approach is presented based on recorrection of abnormal projections, which provides comprehensive and quantitative characterization of TSV etching performance. The key idea is to replace the abnormal projections at specific angles in principles of linear interpolation of neighboring projections, and to distinguish the interface between silicon and air by using phase-retrieval algorithms. It is demonstrated that such a scheme achieves high accuracy in obtaining the etch profile based on the 3D microstructure of the vias, including diameter, bottom curvature radius, depth and sidewall angle. More importantly, the 3D profile error of the via sidewall and the consistency of parameters among all the vias are achieved and analyzed statistically. The datasets in the results and the 3D microstructure can be applied directly to a reference and model for further finite element analysis. This method is general and has potentially broad applications in 3D integrated circuits.

Removal of pharmaceuticals by novel magnetic genipin-crosslinked chitosan/graphene oxide-SO3H composite.

A novel magnetic adsorbent genipin-crosslinked chitosan/graphene oxide-SO3H (GC/MGO-SO3H) composite was prepared and used as adsorbents of environmental pollutant. The GC/MGO-SO3H exhibit typical superparamagnetic behavior. The adsorption characteristics of GC/MGO-SO3H composite to pharmaceuticals were investigated through batch experiments. The maximum adsorption capacity of ibuprofen and tetracycline increases from 113.27 to 138.16 mg/g and 473.25 to 556.28 mg/g with the increase in temperature from 298 to 313 K. The adsorption kinetics and isotherms were investigated in detail to reveal that the kinetics and equilibrium adsorptions are well described by pseudo-second-order kinetic and Freundlich isotherm model, respectively. This study has demonstrated that the GC/MGO-SO3H composite could be utilized as an efficient and with high speed.

CeO2 Nanorods Embedded in Ni(OH)2 Matrix for the Non-Enzymatic Detection of Glucose.

The electrode based on cerium oxide (CeO2) nanorods embedded in nickel hydroxide (Ni(OH)2) matrix were prepared and used for detecting glucose non-enzymatically. The materials were characterized by X-ray diffraction, transmission electron microscopy (TEM), and so on. The results indicate that the response of CeO2/Ni(OH)2 nanocomposite are significantly improved due to the synergetic effect between CeO2 and Ni(OH)2. The optimum CeO2/Ni(OH)2 nanocomposite electrode exhibits a detection range from 2 µM to 6.62 mM, a sensitivity of 594 µA mM-1 cm-2, an estimated detection limit of 1.13 µM, and a response time less than 5 s. In addition, this biosensor also shows good selectivity, long term stability, and accurate measurement in juice on sale.