Experimental Study and Failure Criterion Analysis of Rubber Fibre Reinforced Concrete under Biaxial Compression-Compression

In order to examine the biaxial compression-compression properties of rubber fibre reinforced concrete(RFRC),an experimental study on RFRC under different lateral compressive stresses was carried out by considering different rubber replacement rates and polypropylene fibre contents.The failure modes and mechanical property parameters of different RFRC working conditions were obtained from the experiment to explore the effects of rubber replacement rate and polypropylene fibre content on the biaxial compression-compression properties of RFRC.The following conclusions were drawn.Under the influence of lateral compressive stress,the biaxial compression-compression failure mode gradually developed from a columnar pattern to a flaky pattern,suggesting that the incorporation of rubber and polypropylene fibres into the concrete resulted in a significant change in the development of cracks.For different rubber replacement rates and polypropylene fibre contents,the vertical compressive stress exhibited the same developing trend under the influence of lateral compressive stress.Specifically,the lateral compressive stress imposed the minimum effect on the vertical compressive stress when the rubber replacement rate and polypropylene fibre content were 20%and 0.4%,respectively,and imposed the maximum effect when the rubber replacement rate and polypropylene fibre content were 20%and 0%,respectively.With the increase of rubber replacement rate,the vertical peak stress was significantly reduced,which implies that an appropriate amount of polypropylene fibres can increase the vertical peak stress to a certain extent.Then,the biaxial compression-compression mechanism of RFRC was analysed from the microscopic level by using scanning electron microscope(SEM).Meanwhile,based on Kupfer’s biaxial compression-compression failure criterion and the octahedral stress space,a biaxial compression-compression failure criterion for RFRC was proposed,which was proven to have good applicability.The research results of this study provide important theoretical basis for the engineering application and development of RFRC.

Comparative analyses of aging-related genes in long-lived mammals provide insights into natural longevity

Extreme longevity has evolved multiple times during the evolution of mammals,yet its underlying molecular mechanisms remain largely underexplored.Here,we compared the evolution of 115 aging-related genes in 11 long-lived species and 25 mammals with non-increased lifespan(control group)in the hopes of better understanding the common molecular mechanisms behind longevity.We identified 16 unique positively selected genes and 23 rapidly evolving genes in long-lived species,which included nine genes involved in regulating lifespan through the insulin/IGF-1 signaling(IIS)pathway and 11 genes highly enriched in immune-response-related pathways,suggesting that the IIS pathway and immune response play a particularly important role in exceptional mammalian longevity.Interestingly,11 genes related to cancer progression,including four positively selected genes and seven genes with convergent amino acid changes,were shared by two or more long-lived lineages,indicating that long-lived mammals might have evolved convergent or similar mechanisms of cancer resistance that extended their lifespan.This suggestion was further corroborated by our identifi-cation of 12 robust candidates for longevity-related genes closely related to cancer.

广告态度和广告支出对品牌资产的影响研究

通过对在校大学生的实证研究探讨了广告态度和广告支出对品牌资产的影响,并比较了广告态度维度和广告支出对品牌资产维度的影响差异。研究结果表明:广告态度与广告支出均对品牌资产的某些维度产生直接影响,其中广告态度中的实用性显著正向影响品牌忠诚和品牌知晓/品牌联想,对感知质量没有显著影响;广告态度中的享乐性显著正向影响感知质量和品牌知晓/品牌联想,对品牌忠诚没有显著影响;广告支出仅对品牌知晓/品牌联想具有正向显著影响,对感知质量和品牌忠诚影响不显著。接着对广告支出和广告态度对品牌资产的影响力进行了比较,结果表明,广告支出对品牌知晓/品牌联想的影响最大,其次是广告享乐性,最后是广告实用性。同时研究证实了品牌资产三个维度之间的相互影响关系,其中品牌知晓/品牌联想显著正向影响感知质量和品牌忠诚,同时感知质量显著正向影响品牌忠诚。