Search

This study analyzes the large deformation failure mode and mechanical mechanism of tunnel surrounding rock, with an aim to lessen the damage of high ground stress soft rock tunnel support structure and large deformation of surrounding rock in southwest mountainous area, with Yunnan Changning Tunnel as example for analysis, This paper investigates NPR anchor cable stress compensation support for soft rock tunnel.First, we analyzed the geological conditions and causes of failure of the tunnel through field survey and indoor test.Then, we looked at the main control factors affecting the stability of surrounding rock and the failure mode of surrounding rock of Changning Tunnel.Next, this study proposed the stress compensation support technology with NPR anchor cable as the core.Finally, we analyzed the control effect of surrounding rock of Changning Tunnel under the condition of NPR anchor mesh coupling support through field test.Results show that the main failure modes of the surrounding rock of Changning Tunnel are the compression bending of rock strata and the shear slip between layers.The stress compensation support technology with NPR anchor cable as the core works to effectively control the large deformation of the tunnel surrounding rock in the initial support.The maximum deformation of the tunnel surrounding rock is controlled from 2 150 mm to less than 100 mm, which demonstrates significant control effect.The research results can provide reference for the prevention and control of large deformation of soft rock tunnel.

Climate change has profound effects on the distribution of kelp forests in the Arctic and sub‐Arctic. However, studies on the responses of kelps to climate change, particularly along the sub‐Arctic regions of the Alaska coast, are limited. Eualaria fistulosa is a foundational kelp species in the Aleutian Islands, with an east–west distribution that extends from Japan to southern southwest Alaska. In this study, we utilized a species distribution model (SDM) to explore changes in the future habitat suitability of E. fistulosa under contrasting Shared Socioeconomic Pathway (SSP) scenarios. Our model exhibited relatively high predictive performance, validating our SDM predictions. Notably, the SDM results indicate that minimum sea surface temperature, annual range in sea surface temperatures, and annual mean current velocities are the three most important predictor variables determining E. fistulosa's distribution. Furthermore, the projected geographic distribution of Eualaria is generally consistent with its observed occurrence records. However, under high emission scenarios (SSP5‐8.5), E. fistulosa is predicted to contract its distribution range by 9.0% by 2100, with widespread disappearance along the southeast Alaskan coast and limited northward migration to Kamchatka Krai in Russia and Bristol Bay in Alaska. These findings contribute valuable insights for conservation strategies via addressing climate‐induced alterations in sub‐Arctic kelp distribution. [ABSTRACT FROM AUTHOR]

In perovskite solar cells (PSCs), the selection of the hole‐transport material (HTM) markedly influences both the achievement of high efficiency and overall stability. This study outlines the synthesis of a dopant‐free HTM founded on the donor–acceptor1–acceptor2 (D–A1–A2)‐conjugated structure and its integration into PSCs. The ensuing PSCs showcase a power conversion efficiency of 17.8%, comparable to NiOx inorganic HTM‐based devices and surpassing poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate polymeric HTM‐based devices. The efficiency comparable to NiOx is attributed to the efficient hole extraction and transport facilitated by the conjugated π junctions in the specifically designed structure. Furthermore, these devices exhibit enhanced stability, maintaining 95% of their initial performance for 60 d in an N2 atmosphere without encapsulation. The improved stability primarily arises from the hydrophobic nature of the HTM. The larger π‐conjugated molecules lead to a denser film by reducing intermolecular space, effectively retarding water intrusion and providing superior protection to the perovskite layer. Thus, the dopant‐free D–A1–A2 HTM with an extended conjugated π structure not only effectively enhances device efficiency but also substantially improves device stability. [ABSTRACT FROM AUTHOR]