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Xinyang Yin,Hanqiong Wang,Jinguang Yang,Yan Liu,Yang Zhao,Jinhu Yang Techno-Press 2023 Advances in aircraft and spacecraft science Vol.10 No.3
In order to improve aerodynamic performance of multi-stage axial flow turbines used in aircraft engines, a one-dimensional aerodynamic design and optimization framework is constructed. In the method, flow path is generated by solving mass continuation and energy conservation with loss computed by the Craig & Cox model; Also real gas properties has been taken into consideration. To obtain an optimal result, a multi-objective genetic algorithm is used to optimize the efficiencies and determine values of various design variables; Final design can be selected from obtained Pareto optimal solution sets. A three-stage axial turbine is used to verify the effectiveness of the developed optimization framework, and designs are checked by three-dimensional CFD simulation. Results show that the aerodynamic performance of the optimized turbine has been significantly improved at design point, with the total-to-total efficiency increased by 1.17% and the total-to-static efficiency increased by 1.48%. As for the off-design performance, the optimized one is improved at all working points except those at small mass flow.
Liu XiYue,Yang Jia,Wang YuanQing,Ye YiCong,Li JinGuang,Sun Tong 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.4
To investigate the fracture initiation mechanisms and establish the relationship between the ductile fracture mechanism and macro stress–strain for high-strength structural steel, the mechanical response and fracture behavior of Q460C steel and its butt welds were studied via tests, numerical analysis and scanning electron microscopy (SEM) in this paper. The mechanical properties of high-strength steel (HSS) under diff erent stress triaxialities were studied by uniaxial tensile tests on standard specimens and notched round rods. The fi nite element model is set up according to the characteristic length which is based on SEM observations. By combining experimental results and numerical simulations, the constitutive model and fracture prediction model were established. The relationship between the ductile fracture mechanism and the macro stress strain was obtained. The toughness parameters of the micromechanical model of Q460C steel and its welded joints were compared with those of Q345 steel and seven other types of structural steel from the United States and Japan. The results show that the characteristic length of the crack tip is the key factor aff ecting the accuracy of predicting fracture toughness under a large stress–strain gradient. The toughness predicted by the model is in good agreement with the traditional fracture toughness test results when taking the average value. The experimental results and fi nite element analysis verifi ed the eff ectiveness of the VGM and SMCS micromechanical models in predicting the fracture toughness of Q460C steel and its welded joints, which can provide a theoretical basis and practical guidance for the anti-fracture design and application of HSS structures.
Aerodynamic topology optimization on tip configurations of turbine blades
Min Zhang,Yan Liu,Jinguang Yang,Yuefang Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7
The topology optimization (TopOpt) is adopted in this article to design tip geometries of a turbine blade. Its principle is to modify the porosity, which is one for fluid and is zero for solid. A CFD method coupled with source terms is implemented for numerical simulations. Moreover, to update the porosity, a quasi-sensitivity and an adjoint sensitivity analysis schemes are integrated with the method of moving asymptotes algorithm, respectively. The TopOpt is conducted to design the tip profile of a 2D tip model and of nine axial sections in a 3D turbine blade. Optimized tips are reconstructed and their performance is verified by experiments and CFD. Results indicate that the re-designed novel tip, which has a convexconcave-convex form and is different from flat and cavity tips, has good performance due to getting rid of flow separations above the tip. Hence, the optimized tip can lower total pressure loss in the gap region.
Lusha Ji,Cheng-Chao Zheng,Rui Xu,Longtao Lu,Jiedao Zhang,Guodong Yang,Jinguang Huang,Changai Wu 한국분자세포생물학회 2013 Molecules and cells Vol.36 No.2
Nuclear matrix attachment regions (MARs) regulate the higher-order organization of chromatin and affect the expression of their flanking genes. In this study, a tobacco MAR, TM6, was isolated and demonstrated to remarkably increase the expression of four different promoters that drive gusA gene and adjacent nptII gene. In turn, this expression enhanced the transformation frequency of transgenic tobacco. Deletion analysis of topoisomerase II-binding site, AT-rich element, and MAR recognition signature (MRS) showed that MRS has the highest contribution (61.7%) to the TM6 sequence-mediated transcription activation. Micrococcal nuclease (MNase) accessibility assay showed that 35S and NOS promoter regions with TM6 are more sensitive than those without TM6. The analysis also revealed that TM6 reduces promoter DNA methylation which can affect the gusA expression. In addition, two to-bacco chromatin-associated proteins, NtMBP1 and NtHMGB, isolated using a yeast one-hybrid system, specifically bound to the TM6II-1 region (761 bp to 870 bp) and to the MRS element in the TM6II-2 (934 bp to 1,021 bp) region, respectively. We thus suggested that TM6 mediated its chromatin opening and chromatin accessibility of its flanking promoters with consequent enhancement of transcription.
Jin, Guang,Bae, Eun Young,Yang, Enyue,Lee, Eung Bae,Lee, Won-Kee,Choi, Jin Eun,Jeon, Hyo-Sung,Yoo, Seung Soo,Lee, Shin Yup,Lee, Jaehee,Cha, Sung Ick,Kim, Chang Ho,Cho, Sukki,Jheon, Sanghoon,Park, Jae Lippincott Williams Wilkins 2012 JOURNAL OF THORACIC ONCOLOGY Vol.7 No.5
<P>The 15q25 region has been associated with lung-cancer risk and might also be associated with the prognosis of lung cancer. This study was conducted to determine the impact of a functional polymorphism in the CHRNA3 gene on chromosome 15q25 in the survival of patients with early-stage non-small-cell lung cancer (NSCLC).</P>