Supporting Structure of Steel Corrugated Plate-Mold Bag Concrete and Its Application in a Circular Shaft

To cater to the problems of a poor working environment, a large amount of rebound, and the high energy consumption of sprayed concrete in tunnel engineering, this paper proposes a new support scheme with a steel corrugated plate combined with mold bag concrete. Analytical solutions of stresses for steel corrugated plate and mold bag concrete were deduced based on the thin-walled cylinder, and then their strength safety factors were presented. Subsequently, a series of numerical simulations were conducted to investigate the mechanical performance of the third ring of the main structure based on the ‘load-structure’ 3D model. The numerical results were verified using the classical theoretical analysis and the proposed model, and then parametric studies were performed through the numerical method. Finally, field tests in a circular shaft were carried out to verify the feasibility of the structure and process and the engineering effect. The results show that the combination of steel corrugated plate and mold bag concrete is feasible and can realize rapid support technology for underground engineering, which provides a new idea for the supporting technology of underground engineering such as tunnels

A convex nonlocal total variation regularization algorithm for multiplicative noise removal

Abstract This study proposes a nonlocal total variation restoration method to address multiplicative noise removal problems. The strictly convex, objective, nonlocal, total variation effectively utilizes prior information about the multiplicative noise and uses the maximum a posteriori estimator (MAP). An efficient iterative multivariable minimization algorithm is then designed to optimize our proposed model. Finally, we provide a rigorous convergence analysis of the alternating multivariable minimization iteration. The experimental results demonstrate that our proposed model outperforms other currently related models both in terms of evaluation indices and image visual quality

Stepwise Synthesis of Au@CdS-CdS Nanoflowers and Their Enhanced Photocatalytic Properties

Abstract Fabrication of hybrid nanostructures with complex morphologies and high photocatalytic activity is a difficult challenge because these particles require extremely high preparation skills and are not always practical. Here, hierarchical flower-like Au@CdS-CdS nanoparticles (Au@CdS-CdS nanoflowers) have been synthesized using a stepwise method. The Au@CdS-CdS nanoflowers are consisted of Au core, CdS shell, and CdS nanorods. The UV-Vis absorption range of the Au@CdS-CdS nanoflowers reaches up to 850 nm which covers the whole visible range (400–760 nm). Photoinduced charge transfer property of Au@CdS-CdS nanoflowers was demonstrated using photoluminescence (PL) spectroscopy. Compared to CdS counterparts and Au@CdS counterparts, Au@CdS-CdS nanoflowers demonstrated the highest photocatalytic degradation rate under irradiation of λ = 400–780 nm and λ = 600–780 nm, respectively. Based on structure and morphology analyses, we have proposed a possible formation mechanism of the hybrid nanostructure which can be used to guide the design of other metal-semiconductor nanostructures with complex morphologies

Formation of infrared solitons in graphene ensemble under Raman excitation

The formation of infrared solitons in graphene under Raman excitation is investigated using density-matrix approach. We find that the unique band structure and selection rules for the optical transitions near the Dirac point can result in extremely strong optical nonlinearity. Theoretical investigations with the aid of slowly varying envelope approximation and perturbation theory clearly indicate the existence of bright and dark solitons in Landau-quantized graphene. Actually, the formation of spatial soliton in such a material is the consequence of the balance between nonlinear effects and the dispersion properties. Also, the corresponding carrier frequency is tunable in the infrared range. These results can make us know better the crossover between optical solitons and graphene metamaterials. The predicted nonlinear optical effect in graphene may provide a new possibility for designing high-fidelity graphene-based information processing device

Genomic analysis, trajectory tracking, and field surveys reveal sources and long-distance dispersal routes of wheat stripe rust pathogen in China

Identifying sources of phytopathogen inoculum and determining their contributions to disease outbreaks are essential for predicting disease development and establishing control strategies. Puccinia striiformis f. sp. tritici (Pst), the causal agent of wheat stripe rust, is an airborne fungal pathogen with rapid virulence variation that threatens wheat production through its long-distance migration. Because of wide variation in geographic features, climatic conditions, and wheat production systems, Pst sources and related dispersal routes in China are largely unclear. In the present study, we performed genomic analyses of 154 Pst isolates from all major wheat-growing regions in China to determine Pst population structure and diversity. Through trajectory tracking, historical migration studies, genetic introgression analyses, and field surveys, we investigated Pst sources and their contributions to wheat stripe rust epidemics. We identified Longnan, the Himalayan region, and the Guizhou Plateau, which contain the highest population genetic diversities, as the Pst sources in China. Pst from Longnan disseminates mainly to eastern Liupan Mountain, the Sichuan Basin, and eastern Qinghai; that from the Himalayan region spreads mainly to the Sichuan Basin and eastern Qinghai; and that from the Guizhou Plateau migrates mainly to the Sichuan Basin and the Cen-tral Plain. These findings improve our current understanding of wheat stripe rust epidemics in China and emphasize the need for managing stripe rust on a national scale