Experimental and numerical simulation study of perforation effect of steel pipes subject to the impact loadings of ASC and LSC jets

The perforation effect of steel pipes subjected to the circular-shaped charge (ASC) and linear-shaped charge (LSC) jet were studied by experimental research, and the explicit nonlinear dynamic finite element computer code LS-DYNA was adapted to study the nonlinear responses of the steel pipes, which subjected to the impact of the two different jets, using Lagrangian-Eulerian coupling method. The deformation process and the stress of the steel pipes were described and analyzed, and the simulation results are in good agreement with the experiment data. The studies indicated that under the impact of ASC jet, the steel pipe got a circular incision and a deformation process of local perforation, flocculent shear lip forming and axial shock. Under the impact of LSC jet, the steel pipe got a ship-type incision and a deformation process of coupling of local perforation and dent, whole bending and radial shock. The formation of flocculent shear lip attributes to the radial stress concentration. Under the impact of LSC jet, the whole bending leads to the axial stretch and tearing of the cut tip, and there is a bigger radial plastic deformation area than the damage effect for the impact of ASC jet

Numerical analysis of vibration-isolating effect of vibration-isolating slot under buried pipe subjected to millisecond blasting

Research on vibration-isolating effects of vibration-isolating slot on buried pipe can be done by numerical method, without being disturbed by external environmental factors. It has measured data without relatively high experiment cost and analyzed the influence of some key parameters according to the results of numerical simulation. The results show that the vibration speed of the pipeline with vibration-isolating slot tends to have a larger decrease than those without vibration-isolating slot. What’s more, the homogeneous explosive charge is discrepant in different working conditions, but the vibration-isolating ratio is similar in the vibration-isolating slot with same structure parameter. The millisecond blasting is hardly affected by total explosive charge. But the blasting seismic intensity is influenced by explosive charge in each stage directly

A Comprehensive Analysis of the CaMK2A Gene and Susceptibility to Alzheimer’s Disease in the Han Chinese Population

There is ample evidence suggesting that calcium/calmodulin-dependent protein kinase II alpha (CaMK2A) may play an important role in the pathophysiology of Alzheimer’s disease (AD). This genetic study aimed to investigate whether CaMK2A confers susceptibility to the development of AD in the Han Chinese population. A total of seven single nucleotide polymorphisms (SNPs) within CaMK2A were screened in two independent cohorts from southwestern China (333 AD patients and 334 controls) and eastern China (382 AD patients and 426 controls) to discern the potential association between this gene and AD. In addition, a cross-platform normalized expression resource was used to investigate whether CaMK2A is differentially expressed in the brain between individuals with AD and the controls. In addition, expression quantitative trait loci (eQTL) analysis was used to explore the differences in CaMK2A expression in the brain among different genotypes. The cross-platform normalized data showed significant differences in CaMK2A expression in the hippocampus, entorhinal cortex and temporal cortex between the AD patients and the control subjects (|log FC| > 0.1, P < 0.05); however, only the differences in the hippocampus and temporal cortex remained after the multiple comparisons correction [false discovery rate (FDR)-corrected, P < 0.05]. The frequency of the rs4958445 genotype was significantly different between the AD subjects and the controls from southwestern China (P = 0.013, P = 0.034 after FDR correction). When the two samples were combined, rs4958445 still showed a significant association with AD (P = 0.044). Haplotype analysis indicated that the T-A-C-A-T-C-C and T-G-C-A-T-C-C haplotypes in the southwestern cohort and the T-G-C-G-C-T-C haplotype in the eastern cohort, consisting of rs10051644, rs6869634, rs3797617, rs3756577, rs4958445, rs10515639 and rs6881743, showed a significant association with AD (P = 0.037, P = 0.026 and P = 0.045, respectively). Furthermore, the brain eQTL analysis revealed a significant association between the rs4958445 polymorphism and CaMK2A expression in the inferior olivary nucleus (P = 0.029). Our results suggest an important role for CaMK2A in the pathophysiology of AD in the Han Chinese population, especially the southwestern population

Book Review: Traugott (2022). <i>Discourse Structuring Markers in English. A Historical Constructionalist Perspective on Pragmatics</i>. Amsterdam and Philadelphia: John Benjamins. ISBN: 978-90-272-1091-3

The cognitive-constructionist approach to language has significantly gained prominence, with recent developments expanding its exploration into language change [...

初始/持续因果关系的理论研究及其最新进展

Causation has been a hot topic in a few disciplines. The research on onset/extended causation is a development to causational theories, which attracts great concerns and heated discussion. However, little research has been done on this topic at home. Therefore, it’s of critical significance to introduce onset/extended causation and review the criticism. This article first introduces the definition of onset/extended causation, and then summarizes their distinctive attributes. Previous resear-ches in philosophy and linguistics are focused on and reviewed in detail. Finally, several questions requiring further attention and exploration are also proposed