哈尔滨应用职业技术学院

In this work, the spreading behavior of a Zn solder droplet on TC4 sheet with the help of ultrasonic was studied. Results show that the solder spreads rapidly with the help of ultrasonic due to the high acoustic pressure formed in the droplet center. The spreading center shows complete wetting, while the near-center-region shows spot wetting when using short ultrasonic time. Prolonging the ultrasonic action time contributes the interaction of Zn and Ti at the spreading center, forming intermetallic compound (IMC). The oxide layer remains intact at the spreading front when changing ultrasonic times. Thick IMCs with cracks form when using ultrasonic time longer than 5 s. TC4 substrate and TiZn3 have similar hardness, TiZn3 and TiZn IMC have similar modulus.

The seismic performance of masonry-infilled reinforce concrete (RC) frame buildings is an intricate issue due to the variety and complexity failure mechanisms observed on this type of buildings during an earthquake, mainly due to wall-frame interaction. This leads to seriously damaged infill walls and it can produce large economic losses and even jeopardize human lives in an earthquake event. For this reason, in this study a new type of flexible connection able to reduce the wall-frame interaction, and consequently improving the overall seismic performance of the structure is examined. The research encompasses both experimental and numerical analyses of three distinct cases: a rigid connection (Case 1), a traditionally flexible connection (Case 2), and the new proposed type of flexible connection (Case 3). The in-plane and out-of-plane seismic performance is analyzed and compared for these cases. As a result of the study, the new type of flexible connection effectively reduced in-plane damage of the infill walls and minimized undesirable infill-frame interaction. Compared with rigid and traditional connections, the energy dissipation capacity increased by 37.7% and 3.5% for the masonry-infilled RC frame structure with a new flexible connection. At the same time, the out-of-plane strength and stiffness of the new flexible connection increased by 119.8% and 104.2% in the same prior in-plane drift ratio than that of traditional flexible connection. It is concluded that the steel cable structure (the U-bars are connected to the frames to ensure out-of-plane stability of infill walls.) can improve the restraint of frames on infill walls, which is beneficial to development of out-of-plane horizontal arch mechanism.

Micro-arc oxidation (MAO) is one of the most effective techniques for producing ceramic coatings on metal surfaces and is widely used for metal surface modification. However, energy is wasted due to the dispersion of energy when handling large workpieces. Scanning micro-arc oxidation (SMAO) is a coating process developed based on conventional micro-arc oxidation, where electrode confinement is carried out during the scanning process thus saving energy. In this paper, SMAO is further investigated and simulated using simulation software, which greatly saves the experimental cost. The results show that increasing the number of scans increases the thickness of the micro-arc oxidized film, while the scanning speed is the opposite. Both anodic oxidation and passivation zones exist at the periphery of the SMAO region, the roughness of the SMAO film layer decreases from the center to the edge, and the anodic oxidation reaction mainly occurs at the edge zone of the discharge region. The thickness of the film layer is about 17 um in a single scan, and the thickness of the film layer can reach 50 um after several scans, and there is a porous structure on its surface, which is favorable for the adsorption and diffusion of gas molecules. The results show that SMAO is suitable for producing large-volume and large-area metal surface coating, and it is a feasible metal surface coating process.

In the milling process of thin-walled parts, chatter is very easy to occur, which has a very adverse impact on the surface quality and machining efficiency of the workpiece. In order to solve the problem of low accuracy of milling state identification caused by few initial samples and dynamic changes in the milling process, a hybrid online evolutionary chatter identification model combining unsupervised learning and supervised learning was proposed. First of all, aiming at the problem that traditional K-means algorithm is difficult to adapt to online dynamic clustering of milling chatter, an online incremental-sparse K-means algorithm (ISK-Means) was proposed, and the dynamic incremental-sparse strategy of K-means was designed. Second, aiming at the problem that the online sequential extreme learning machine (OS-ELM) algorithm directly adds its predicted samples to the training sample set during the incremental learning process, and the pseudo-samples in the training sample set would lead to the degradation of the OS-ELM model, a hybrid online evolutionary chatter identification model combining the ISK-means and the OS-ELM was proposed, and the online identification and evolution strategy was designed. Finally, the experimental results show that the ISK-means algorithm can greatly improve the clustering efficiency and is suitable for milling chatter online dynamic clustering. Meanwhile, compared with the existing model, the recognition accuracy of the hybrid online evolutionary chatter recognition model combined with ISK-means algorithm and OS-ELM algorithm is improved by 1.31%. This is of great significance for the online control of subsequent chatter.

As a new food raw material, Acer truncatum seed has been used in the production of edible oil. However, the research on the processing residue (seed meal) has not been reported. The Acer truncatum seed meal was hydrolyzed by seven enzymes and the enzymic polypeptides obtained were characterized by thermogravimetric analysis, gel permeation chromatography, fourier transform infrared spectroscopy and zeta pals dynamic light scattering. In addition, the degree of hydrolysis, amino acid composition, antioxidant activity, α-glucosidase inhibition activity and α-amylase inhibition activity of enzymatic polypeptide were evaluated. The results showed that the yields, average molecular weights, average particle sizes and zeta potentials of enzymic polypeptides obtained were 20.5–40.2