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After a long period of geological tectonic action, the rock mass develops defects such as pores and fissures of different sizes and scales. The mechanical properties of the rock are largely affected by these discontinuous structures, and there will be obvious stress concentration at the edge of the hole inside the rock. Under the action of concentrated stress, cracks initiate, expand, and penetrate from the edge of the hole to form the final fracture surface and cause instability and failure of the rock mass. In practical engineering, due to the limitation of various factors, it is impossible to conduct uniaxial compressive strength test for each geotechnical engineering. Therefore, the rock in the weak part of the project can be selected as the test specimen before the indoor physical tests. In this paper, the static uniaxial compression test of specimens with circular holes with different diameters is carried out. Digital Image Correlation (DIC) monitoring system is used to observe the test process in real time; then, the data from uniaxial compression test and DIC monitoring test are obtained. At the same time, the macroscopic failure characteristics and crack propagation law of rock specimens are obtained, and the evolution law of strain field during the failure process of rock specimens is also obtained. Meanwhile, Realistic Failure Process Analysis (RFPA) is carried out to verify the accuracy of static uniaxial compression physical tests numerically. Physical tests show that the uniaxial compressive strength of marble specimens with circular holes and the dispersion of measured peak stress data decrease with the increase of hole diameter. The main failure type of marble specimens with circular holes is tension shear failure; the macroscopic failure zone of the sample, the strain field localization zone, and the maximum shear stress field of the numerical test are distributed in a semi-“X” shape with the hole as the center. The localization zone of the strain field on the specimen is usually the region of crack initiation, propagation, and penetration on the surface of the marble specimens. It also shows that specimen breaks in the radial direction along the y-axis of the circular hole, and cracks connecting both ends of the circular hole and the specimen are generated on the specimen. It is of great theoretical value and practical significance to the influence of the cavities in the rock specimens on the stress and strain characteristics and the initiation, propagation, and penetration modes.

The two genera, Chaenotetrastichus Graham and Styotrichia LaSalle (Chalcidoidea: Eulophidae: Tetrastichinae), are newly recorded from the Oriental region, based on material reared from the pupae of Auplopus carbonarius (Scopoli) (Hymenoptera: Pompilidae) and a Pisoxylon species (Hymenoptera: Crabronidae), respectively, collected using trap-nests. Styotrichia pisoxylona Cao & Zhu sp. nov. is described and illustrated as a gregarious endo-parasitoid of Pisoxylon sp. The generic diagnosis, biology, and distribution of Chaenotetrastichus and Styotrichia are updated. All described species of the two genera are reviewed and a key to them is provided. Based on morphology and available sequences of the D2 expansion region of 28S ribosomal DNA (28S D2), the relationships between the two genera and other members of the subfamily Tetrastichinae are tentatively discussed. The phylogenetic analysis of 28S D2 confirms that the two genera with enlarged mandibles, which are associated with aculeate Hymenoptera, are not closely related. DNA barcodes (mitochondrial cytochrome c oxidase I, COI) of the newly described species and C. semiflavus (Girault) are provided and analyzed alongside publicly available COI sequences of related taxa. The result suggests that the genetic or species diversity of Chaenotetrastichus is underestimated. [ABSTRACT FROM AUTHOR]

A stable and highly active core‐shell heterostructure electrocatalyst is essential for catalyzing oxygen evolution reaction (OER). Here, a dual‐trimetallic core‐shell heterostructure OER electrocatalyst that consists of a NiFeWS2 inner core and an amorphous NiFeW(OH)z outer shell is designed and synthesized using in situ electrochemical tuning. The electrochemical measurements of different as‐synthesized catalysts with a similar mass loading suggest that the core‐shell Ni0.66Fe0.17W0.17S2@amorphous NiFeW(OH)z nanosheets exhibit the highest overall performance compared with that of other bimetallic reference catalysts for the OER. Additionally, the nanosheet arrays were in situ grown on hydrophilic‐treated carbon paper to fabricate an integrated three‐dimensional electrode that affords a current density of 10 mA cm−2 at a small overpotential of 182 mV and a low Tafel slope of 35 mV decade−1 in basic media. The Faradaic efficiency of core‐shell Ni0.66Fe0.17W0.17S2@amorphous NiFeW(OH)z is as high as 99.5% for OER. The scanning electron microscope, transmission electron microscope, and X‐ray photoelectron spectroscopy analyses confirm that this electrode has excellent stability in morphology and elementary composition after long‐term electrochemical measurements. Importantly, density functional theory calculations further indicate that the core‐shell heterojunction increased the conductivity of the catalyst, optimized the adsorption energy of the OER intermediates, and improved the OER activity. This study provides a universal strategy for designing more active core‐shell structure electrocatalysts based on the rule of coordinated regulation between electronic transport and active sites. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Animal Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)