STRENGTH PROPERTIES ANALYSIS OF J55 TUBING PREMIUM CONNECTION

Objective Analysis of torque screwing performance and four kinds of ultimate failure stress distribution of the J55 high strength no shoulder tubing premium connection,the inner wall of the tubing connection is smooth and alignment in favor of the eccentric wear of pumping rod. Methods Establish theoretical model for the specifications of 73. 02 × 5. 51 mm J55 high strength special thread joint pipe,stress analysis、four kinds of limit load failure（ stretched to failure、compressed to failure、internal pressure to failure、external pressure to failure） stress distribution and the theoretical limit failure load analysis,stress distribution and rationality analysis of threaded joints under various conditions of the whole stress,the stress analysis of sealing ring contact. Results The finite element analysis shows that the stress distribution of the oil pipe torque screwing was reasonable,sealing rings were kept in high contact stress,and joints on the top end of the face as a assisting seal has been maintained at high pressure,the main seal and end assisting seal of Teflon seal ring were work together,the joints shows good sealing ability. The failure of four kinds of limit load（ respectively as 408. 9 k N、584. 1 k N、84. 0 MPa、87. 0 MPa） are better than the strength requirements of the round thread in the API standard. The stress distribution of the threaded joint is reasonable. Conclusion The middle diameter of the threaded joint during the torque screwing can be reduced appropriately,in order to improve the performance of anti adhesion; in four kinds of limit load failure mode,the performance of high strength and special screw thread joint is good,accord with strength requirement of the specification of round thread in the API standard; the main seal and auxiliary seal effect of sealing ring is good

Key role of Nb5+ in achieving water-resistant red emission in K2Ta1-xNbxF7:Mn4+ phosphors

Mn4+-activated fluoride is one of the most important red phosphors for white light-emitting diodes (WLEDs) with high color rendering index (CRI). Due to a lack of water resistance, their potential applications are limited. Although surface coating strategies improve the waterproof stability of fluoride red phosphors, they have downsides. It was found that Nb5+ plays an important role in improving the water resistance of Mn4+-activated oxyfluorides by preventing the hydrolysis of [MnF6]2-. In this work, the influence of Nb5+ on the waterproof stability of Mn4+-activated fluorides was explored. A set of synthesized K2Ta1-xNbxF7:Mn4+ phosphors exhibit tunable and superior water resistance. The photoluminescence (PL) intensity of the representative sample K2Ta0.6Nb0.4F7:5%Mn4+ remains nearly 100% of its initial value even after being immersed in water for 60 min, which is significantly higher than the commercial K2SiF6:Mn4+ red phosphor (8.7%). Our findings open up new possibilities for the development of waterproof fluoride red phosphors. © 2023 Elsevier Ltd and Techna Group S.r.l

Analysis of the role of Purα in the pathogenesis of Alzheimer's disease based on RNA-seq and ChIP-seq

Abstract Purine rich element binding protein A (Purα), encoded by the Purα gene, is an important transcriptional regulator that binds to DNA and RNA and is involved in processes such as DNA replication and RNA translation. Purα also plays an important role in the nervous system. To identify the function of Pura, we performed RNA sequence (RNA-seq) analysis of Purɑ-KO mouse hippocampal neuron cell line (HT22) to analyze the effect of Purα deletion on neuronal expression profiles. And combined with ChIP-seq analysis to explore the mechanism of Purα on gene regulation. In the end, totaly 656 differentially expressed genes between HT22 and Purα-KO HT22 cells have been found, which include 7 Alzheimer’s disease (AD)-related genes and 5 Aβ clearance related genes. 47 genes were regulated by Purα directly, the evidence based on CHIP-seq, which include Insr, Mapt, Vldlr, Jag1, etc. Our study provides the important informations of Purα in neuro-development. The possible regulative effects of Purα on AD-related genes consist inthe direct and indirect pathways of Purα in the pathogenesis of AD