Effect of Groove Texture on Deformation and Sealing Performance of Engine Piston Ring

During the present study, a double groove texture was designed on the surface of a piston ring to improve the sealing performance between the piston ring and cylinder liner. The experimental design method was used to fabricate the test plan according to the groove width, depth, and spacing. By using the thermal–structural coupling analysis method, the finite element analysis of the standard piston ring and the textured piston ring was carried out to simulate the deformation state of the cylinder liner system of the piston ring group during the working stroke. The piston rings with different parameters designed by the test scheme were manufactured by wire electrical discharge machining, and the self-made experiment device carried out the sealing test. The results showed that the groove texture could improve the sealing performance of the piston ring, and the analyzed results demonstrated that the groove texture had little effect on the maximum deformation of the piston ring. Still, it could significantly reduce the minimum deformation of the piston ring group. A piston ring with groove texture would improve the sealing performance and reduce the deformation during the work stroke. During the test, the average deformation of the No.7 piston ring group, with a groove depth of 1 mm, a groove width of 0.5 mm, and a groove spacing of 0.1 mm, was the smallest, about 29.6% lower than that of the standard piston ring group. The sealing performance of the No.7 piston ring group was the best, and the reduction rate of the top gas leakage rate was 52.18%. During the present study, the sealing performance of the piston ring was improved by designing the grooved structure on the piston ring surface, thereby improving the fuel economy and power performance of the engine. The present study could provide a reference for the engineering field to design a piston ring with high sealing performance

Influence of CO2-wettability on CO2 migration and trapping capacity in deep saline aquifers

CO2 migration and trapping capacity in deep saline aquifers are highly influenced by various rock and fluid parameters. One of the key parameters, which has received little attention, is CO2-wettability. We thus simulated the behavior of a CO2 plume in a deep saline aquifer as a function of rock wettability and predicted various associated CO2 migration patterns and trapping capacities. We clearly show that CO2-wet reservoirs are most permeable for CO2; CO2 migrates furthest upwards and the plume has a candle-like shape, while in a water-wet reservoir the plume is more compact and rain-drop shaped. Furthermore, higher residual trapping capacities are achieved in water-wet rock, while solubility trapping is more efficient in CO2-wet rock. We thus conclude that rock wettability has a highly significant impact on both CO2 migration and trapping capacities and that water-wet reservoirs are preferable CO2 sinks due to their higher storage capacities and higher containment security

Exploration of n- and p-type doping for two-dimensional gallium nitride: charged defect calculation with first principles

The calculation of charge transition energy level (CTL) and defect formation energy are of significance to explore potential n-type or p-type doping in materials. Based on the first-principles method, this paper systematically studied the structural, magnetic, and defect properties of 12 kinds of dopants in the two-dimensional hexagonal gallium nitride (2D h-GaN) system. The results show that the most stable charge states (MSCSs) for n-type systems are 0 and 1+, and all the n-type substitutes act as shallow donors. The MSCSs of the p-type systems are 1−, 0 and 1+, and the acceptor ionization energy is distributed higher than the valence band maximum (VBM) from ~1.25 to 2.85 eV, acting as deep acceptors, which will capture electrons (holes) in n-(p-type) 2D h-GaN and affect the carrier conductivity. Thus, it is difficult to achieve p-type doping through a single defect in 2D h-GaN, and complex defects are necessary to achieve p-type doping experimentally

Correlation between heparanase gene polymorphism and susceptibility to endometrial cancer

Abstract Background Endometrial cancer is one of the three most common malignancies in the female genital tract. Previous studies have demonstrated the association between heparanase (HPSE, OMIM 604,724) single‐nucleotide polymorphism (SNP) and cancer risk in several cancers. However, its role in endometrial cancer remains unclear. The present study investigated the effects of HPSE SNPs on the susceptibility and clinicopathological parameters in patients with endometrial cancer. Methods HPSE SNPs of rs4693608 (G > A) and rs4364254 (C > T) were analyzed using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) assay in 270 endometrial cancer patients and 320 healthy controls. Results The investigation indicated that the HPSE SNP rs4693608 with GG showed a protective effect from EC in both codominant (adjusted OR = 0.41, 95%CI = 0.21–0.81, p = .026) and recessive models (adjusted OR = 0.43, 95%CI = 0.22–0.82, p = .0076). No significant differences were found in the incidences of EC patients with the rs4364254 polymorphisms compared to controls. Moreover, a significantly increased distribution of A/A (rs4693608) was observed in patients with grade ≥ 2 (p = .03) and in patients with positive cervical invasion (p = .042) while patients with T/C (rs4364254) had lower tumor grade. Conclusion Our study suggested that HPSE SNP of rs4693608 correlated strongly with susceptibility to EC, and HPSE SNPs might be a potential biomarker for prognosis of endometrial cancer

Discussion on Chinese Ancient Literature Translation Based on the English Translation of the Book of Songs

The Book of Songs is an important part of Chinese traditional culture and enjoys a high reputation at home and abroad. This article is based on Turi’s theory of translation norms, and takes the English translation of The Book of Songs · Jing Jing by Richard Jacob and Xu Yuanchong as the research object. Comparative studies are made on the historical nature of understanding, the normativeness of translation, and the application of the fusion of horizons in the two versions of the Book of Songs. Incorporating history into translation brings the translation closer to the roots of history. The comparative research method proposed in this article can be widely used in various ancient literature studies, and has important theoretical and application values

Campus Economic Analysis Based on K-Means Clustering and Hotspot Mining

With the advent of the era of big data and the development and construction of smart campuses, the campus is gradually moving towards digitalization, networking and informationization. The campus card is an important part of the construction of a smart campus, and the massive data it generates can indirectly reflect the living conditions of students at school. In the face of the campus card, how to quickly and accurately obtain the information required by users from the massive data sets has become an urgent problem that needs to be solved. This paper proposes a data mining algorithm based on K-Means clustering and time series. It analyzes the consumption data of a college student’s card to deeply mine and analyze the daily life consumer behavior habits of students, and to make an accurate judgment on the specific life consumer behavior. The algorithm proposed in this paper provides a practical reference for the construction of smart campuses in universities, and has important theoretical and application values