西安航空职业技术学院是一所全日制公办普通高等职业院校，坐落于陕西省西安市，是国家示范性高等职业院校，教育部第二批现代学徒制试点单位，教育部“高端技能型、应用型人才联合培养百千万交流计划”项目院校，被国家发改委、教育部确定为“十三五”产教融合发展工程规划项目建设单位，被教育部、财政部确定为“中国特色高水平高职学校和专业建设计划”立项建设单位；被陕西省遴选为优质院校立项建设单位、陕西省普通高校一流高职院校建设单位。学校始于1958年创建的第三机械工业部阎良第一航空工业工人技术学校，1979年更名为空军航空工程部第三技工学校。1985年学校改制为全日制中等专业学校，1994年更名为空军西安航空工程学校。2001年由空军移交陕西省管理，升格为高等职业院校，定名西安航空职业技术学院。据2020年2月学校官网显示，学校有南、北、东3个校区，占地面积1000余亩；设有8个二级学院，50余个专科专业；有专、兼任教师750名，在校生12000余人。
This study employed hot isostatic pressing (HIP) to reduce defects in cast aluminum alloys and investigated the influence of HIP holding temperature on the microstructure, mechanical properties, and corrosion resistance of the alloys. Different HIP temperatures were applied to the aluminum alloys, and the resulting changes in grain size, secondary phase distribution, and material properties were analyzed. The microstructure of the materials was observed and analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), and optical microscopy (OM). Electrochemical corrosion (EC) technology was utilized to fit polarization curves and equivalent circuit models, confirming the dissolution of secondary phases and the improvement of corrosion resistance. The results indicated that HIP treatment significantly improved the microstructure of the alloys, especially at HIP temperatures of 515 °C and 525 °C, where grain refinement was obvious and the distribution of secondary phases became more uniform. Tensile strength and corrosion resistance were also enhanced. Additionally, this study further analyzed the evolution of grain boundary phases and their corresponding corrosion mechanisms.
To address the issues of low search efficiency, poor convergence accuracy, and susceptibility to local optima in the sand cat swarm optimization (SCSO) algorithm, this paper proposes a modified sand cat swarm optimization algorithm incorporating gold exploration strategy and sparrow alert mechanism, termed the GE-SA ISCSO algorithm. Firstly, Bernoulli chaotic mapping is employed to generate a more uniformly distributed initial population. Secondly, the gold exploration strategy is embedded into the position update formula of sand cats, providing more candidate search directions for locating prey. After the SCSO algorithm search phase is completed, a sparrow alert mechanism is further introduced to accelerate convergence and enhance the ability to escape local optima. To verify the effectiveness and superiority of GE-SA ISCSO, comparative tests are conducted on 21 classical benchmark functions and the CEC2022 test set function against several metaheuristic optimization algorithms. The performance of GE-SA ISCSO is evaluated using the Wilcoxon rank sum test, box plot analysis, and five qualitative methods. Test results show that GE-SA ISCSO achieves higher convergence accuracy, faster convergence speed, and a stronger capability to avoid local optimal solutions, demonstrating outstanding performance in solving complex numerical optimization problems. In addition, six engineering design problems and a photovoltaic power forecasting task are introduced to further assess the comprehensive performance of the proposed algorithm. For all six engineering design problems, GE-SA ISCSO attains the best results among all comparative algorithms, exhibiting excellent optimization capability. In particular, compared with the original the SCSO algorithm, the best objective values obtained by GE-SA ISCSO are reduced by 15.42
In order to optimize the porous structure and impurity phase caused by lithium volatilization, zirconium deficiency and sintering agent addition were adopted simultaneously to prepare Li2Mg3Zr0.94O6—x LiF(x = 0w–5t.
To reduce the windage loss caused by hydrodynamic behavior, this study optimizes the parameters of the windshield based on the analysis of the drag reduction mechanism of the windshield. CFD was used to analyze the flow field characteristics to study the influence of the windshield on the motion state of the fluid around the gears and to clarify the drag reduction mechanism of the windshield. The control variable method is adopted to study the influence of the opening at the meshing area of the gear pair and the oil drainage groove on the drag reduction effect of the windshield to optimize the design parameters of the windshield. The research results show that: the drag reduction effect is optimal when the windshield covers the three surfaces of the spiral bevel gear, and the windage power loss is minimized when the gap between the windshield and the gear surface is 1 mm. Without affecting the meshing motion of the gear pair, the smaller the meshing opening, the smaller the windage of the gear pair. When an oil drainage groove with a 10 degrees sector-shaped opening is designed at the position where the included angle between the meshing-out side of the gear pair and meshing center is 45 degrees, the drag reduction effect of the windshield is the best.
In this study, the surface tension of molten slag was measured using the hanging ring method. Based on the ion and molecular coexistence theory (IMCT), an activity prediction model for the CaO-SiO2-MgO-Al2O3-CaF2 slag system was established, and a corresponding surface tension model was subsequently derived. The investigation explores the effects of basicity R = (w(CaO)/w(SiO2)), the mass ratio w(MgO)/w(Al2O3), and the Al2O3 mass fraction (w, mass fraction of the corresponding oxide). Results show that the surface tension increases with higher values of R, w(MgO)/w(Al2O3), and w(Al2O3) content. The proposed model exhibits high predictive accuracy and provides a reliable tool for evaluating the surface tension of multicomponent blast furnace slags.
