Modeling on Heterogeneous Structure in Acceleration Regime of Gas-Solid Riser Flows

Recent measurement of solid concentration in gas-solid riser flows by Electric Capacitance Tomography (ECT) reveals a strong heterogeneous structure, typically represented by a core-annulus-wall zone pattern. In this paper we present a mechanistic model in which the formation of the heterogeneous structure is due to the radial migration of solid flow from the wall toward center as well as due to the non-uniform acceleration of solids across the cross-section near the bottom of the riser. Firstly we present the general governing equations and discuss problem closure; then a simplified model with one-way flow coupling between the wall region and the core-annulus region is proposed to simulate the formation and development process of heterogeneous flow structures in the riser. Typical results of the three-zone flow structure along the riser are illustrated, which include the axial distributions of solids concentration and phase velocities in each zone, in addition to the pressure distributions. The model is also validated against the ECT measurements

Diffusion Models and Semi-Supervised Learners Benefit Mutually with Few Labels

In an effort to further advance semi-supervised generative and classification tasks, we propose a simple yet effective training strategy called dual pseudo training (DPT), built upon strong semi-supervised learners and diffusion models. DPT operates in three stages: training a classifier on partially labeled data to predict pseudo-labels; training a conditional generative model using these pseudo-labels to generate pseudo images; and retraining the classifier with a mix of real and pseudo images. Empirically, DPT consistently achieves SOTA performance of semi-supervised generation and classification across various settings. In particular, with one or two labels per class, DPT achieves a Fr\'echet Inception Distance (FID) score of 3.08 or 2.52 on ImageNet 256x256. Besides, DPT outperforms competitive semi-supervised baselines substantially on ImageNet classification tasks, achieving top-1 accuracies of 59.0 (+2.8), 69.5 (+3.0), and 74.4 (+2.0) with one, two, or five labels per class, respectively. Notably, our results demonstrate that diffusion can generate realistic images with only a few labels (e.g., <0.1%) and generative augmentation remains viable for semi-supervised classification. Our code is available at https://github.com/ML-GSAI/DPT.Comment: Accepted to NeurIPS 202

Rare Earth Eu Doped PtRu/C Catalysts and Their Properties for Methanol Electrooxidation

Commercially available PtRu/C catalyst was doped with Eu by chemical reduction and sintering, resulting in PtRuEux/C catalysts with different Eu contents. The catalysts were characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Results showed that Eu doping did not change the average size of the PtRu/C catalysts (ca 3 nm), and their surfaces were modified by both Eu metal and oxide. Cyclic voltammetry and chronoamperometry demonstrated that the activity of the PtRuEux/C catalysts was higher than that of commercial PtRu/C for methanol electrooxidation. Among the PtRuEux/C catalysts, PtRuEu0.3/C exhibited the best performance. The electrocatalytic oxidation of methanol on the catalyst was further investigated by in situ Fourier transform infrared (FTIR) spectroscopy at molecular level. Results indicated that the adsorbed species derived from the dissociative adsorption of methanol on the catalysts were linear. bonded CO (COL). Eu doping decreased the oxidation potential of COL and thus significantly enhanced the activity of the catalysts and their tolerance to CO.National Natural Science Foundation of China [20833005, 20828005]; Scientific Research Foundation, Ministry of Education ; Opening Foundation of the State Key Laboratory for Physical Chemistry of Solid Surface of Xiamen University ; Innovation Project of Guangxi Graduate Education, Chin

catena-Poly[[aqua­dioxidouranium(VI)]-μ3-4,4′-oxydibenzoato]

The title compound, [UO2(C14H8O5)(H2O)]n, is a polymeric UO2 complex bridged by 4,4′-oxydibenzoate ligands. One carboxyl­ate group of the bridging ligand chelates a uranyl cation while the other carboxyl­ate group of the ligand bridges two other two uranyl cations, forming a double-chain polymeric structure. The central UVI atom is seven-coordin­ated in a distorted UO7 penta­gonal-bipyramidal geometry. In the crystal structure, O—H⋯O hydrogen bonding links the polymeric chains into a three-dimensional supra­molecular framework. Within the bridging ligand, the two benzene rings are oriented at a dihedral angle of 59.0 (2)°

Iron and Alzheimer’s Disease: From Pathogenesis to Therapeutic Implications

As people age, iron deposits in different areas of the brain may impair normal cognitive function and behavior. Abnormal iron metabolism generates hydroxyl radicals through the Fenton reaction, triggers oxidative stress reactions, damages cell lipids, protein and DNA structure and function, and ultimately leads to cell death. There is an imbalance in iron homeostasis in Alzheimer’s disease (AD). Excessive iron contributes to the deposition of β-amyloid and the formation of neurofibrillary tangles, which in turn, promotes the development of AD. Therefore, iron-targeted therapeutic strategies have become a new direction. Iron chelators, such as desferoxamine, deferiprone, deferasirox, and clioquinol, have received a great deal of attention and have obtained good results in scientific experiments and some clinical trials. Given the limitations and side effects of the long-term application of traditional iron chelators, alpha-lipoic acid and lactoferrin, as self-synthesized naturally small molecules, have shown very intriguing biological activities in blocking Aβ-aggregation, tauopathy and neuronal damage. Despite a lack of evidence for any clinical benefits, the conjecture that therapeutic chelation, with a special focus on iron ions, is a valuable approach for treating AD remains widespread