Guilin University of Aerospace Technology (GUAT) is a public university in Guilin, Guangxi, China.GUAT offers Bachelor's degrees and higher education diplomas in engineering and technology, as well as management, business and arts. GUAT was founded in 1979 and run by the former Aerospace Ministry of China, and has over 10,000 students.
In this study, the shrinkage evolution characteristics of Red Clay under Wetting–Drying Cycles were systematically analyzed through laboratory tests. The results indicate that the shrinkage deformation of Red Clay exhibits an S-shaped nonlinear growth trend characterized by "fast first and then slow". Specifically, it can be divided into three stages: during the initial response stage, samples with high water content and low dry density exhibit larger shrinkage increments; a significant transition occurs during the rapid change stage; and in the stabilization stage, it completely transforms into the opposite correspondence. To address the prediction challenges posed by the small-sample size and high volatility, an Empirical Bayes residual-corrected grey prediction model, EBGM(1,1), was constructed. The results indicate that, across the entire sample, the Mean Absolute Percentage Error (MAPE) for both the linear and volumetric shrinkage rates of the modified model decreased by approximately 50
This study investigates the effectiveness of a single-degree-of-freedom (SDOF) tuned vibration absorber (TVA) in reducing vibrational amplitudes in fluid-conveying pipes. Using Euler-Bernoulli beam theory, equations of motion for both the pipe and TVA are developed, then discretized and solved via the Galerkin method, incorporating the first four vibrational modes. An analytical expression for natural frequencies under simply supported boundary conditions is also derived to support optimal TVA design. Numerical results are validated and followed by a parametric analysis illustrating that increased fluid velocity amplifies vibrations. However, a well-designed TVA can reduce these amplitudes by up to 80
To compensate for the large positive temperature coefficient of resonant frequency in the La0.5Na0.5TiO3 perovskite structure ceramic material, laminated La0.5Na0.5TiO3–Sm0.5Li0.5TiO3 (LNT–SLT) microwave dielectric ceramic systems were designed with tunable layer mass fractions. Among the various compositions of xgLNT-(2−x)gSLT (x = 0.5, 0.6, 0.7, 0.8 and 0.9, where ‘g’ denotes grams) and sintering temperatures of 1200–1400 °C, the most noteworthy results indicate that interfacial diffusion of A-site cations contributes to the development of a chemically graded region, which becomes more pronounced at higher sintering temperatures (1300–1400 °C). Additionally, relatively higher sintering temperatures intensify this interfacial diffusion and structural disorder, ultimately leading to a decrease in Q × f values in the xgLNT-(2−x)gSLT (x = 0.7) from 1421.1 to 440.6 GHz. Microwave dielectric measurements reveal that the temperature coefficient of frequency (τf) varies approximately linearly with increasing LNT content, wherein the sample with x = 0.5 sintered at 1250 °C for 4 h achieves a near-zero τf value of approximately − 3.1 ppm/°C and a high εr 76.5, thus demonstrating superior temperature stability. Moreover, this study presents a promising strategy for the development of advanced bilayer ceramic systems and highlights their potential in communication devices.
This study develops a dynamic framework to examine the co-evolution between technology applicability and enterprise innovation strategies within knowledge networks. Departing from traditional static models, we conceptualize technology applicability as an endogenous construct shaped by network position, adoption patterns, and intrinsic technological characteristics. A three-equation system is formulated to capture the bidirectional relationships among innovation strategies, network centrality, and evolving technology applicability. Empirical validation is conducted using longitudinal data from the USPTO, NBER, and Compustat, incorporating patent citation networks and firm-level innovation metrics. The findings provide evidence consistent with threshold effects, feedback loops, and non-linear dynamics: firms with high absorptive capacity respond more intensively to technology applicability signals, leading to structural shifts in knowledge diffusion. Moreover, the interaction between network centrality and technology applicability appears to explain persistent heterogeneity in innovation outcomes. These results offer a framework for understanding co-evolutionary dynamics in innovation ecosystems and suggest practical implications for strategic innovation management and policy design.
To promote the engineering application of casing treatment, this paper proposes the concept of discrete circumferential groove casing treatment. Taking a high-speed subsonic axial compressor rotor as the research object, with the circumferential treatment range fixed at 1/3, a multi-channel unsteady numerical simulation method is employed to investigate the effects of four circumferential groove casing treatment configurations with different distribution patterns on the aerodynamic performance and stability margin of the compressor. The results indicate that the distribution pattern of casing treatment has little impact on the total pressure ratio and adiabatic efficiency of the compressor but has a significant effect on its stability margin. The discrete casing treatment periodically connects the pressure surface and suction surface of the blade tip, reduces the pressure difference, weakens the mass flow rate and momentum of the tip leakage flow, and improves the tip flow state of several channels, which is the fundamental reason for the expansion of the compressor stability margin. In the six-channel simulation, the casing treatment structure distributed with an interval of one pitch exhibits the best stability expansion effect, with the overall stability margin improvement reaching 6.49
