18 research outputs found
Experimental investigation of the tribological property of low viscosity lubricant under micro confined space
Biotribological behaviour of Vitamin E-blended highly cross-linked UHMWPE in a hip joint simulator
Influence of Test Parameters on the Evaluation of Chocolate Silkiness Using the Tribological Method
Silkiness is an extremely important attribute in high-end chocolate, and tribology is one of the commonly used methods of evaluating certain properties of the relevant food. In this study, based on three commercial chocolates of the same brand, the silky sensation was assessed by means of the professional sensation evaluation method. Artificial saliva was employed to obtain the mixed solutions with different chocolates, and their viscosity and coefficient of friction (CoF) were measured under different test parameters. The correlation of chocolate silkiness with the viscosities and average CoFs (aCoFs) are later discussed. The results showed that the silkiness of the three chocolates were negatively correlated with cocoa concentration and weakly correlated with viscosity. As the chocolate percentage decreased, the aCoF of the mixed solutions decreased, but the aCoF of the mixed solutions increased in relation to the cocoa concentration. In combination with the correlation coefficient of chocolate silkiness with the aCoFs, it was considered that 75% chocolate solutions using the Two-PDMS pair could be representative of the silkiness characteristic in oral processing at suitable operated parameters. The study results provide an insight into the rapid evaluation and development of similar attributes of high-end food
Optimization of CMP processing parameters for Si based on response surface method
To improve the polishing efficiency and precision, the optimum processing parameters of Si in the chemical mechanical polishing (CMP) process were analysed by CMP experiments and response surface methodology. The results show that polishing pressure has the largest influence on the material removal rate and surface roughness of Si polishing. The second largest influential factor is polishing rotational speed and the third is polishing fluid flow rate. The prediction models of material removal rate and surface roughness are established. The optimum processing parameters are obtained when the polishing pressure is 48.3 kPa, polishing rotational speed is 70 r/min and polishing fluid flow rate is 65 mL/min with the prediction models and by experiments. With these processing parameters, the material removal rate and surface roughness are 1 058.2 nm/min and 0.771 nm, respectively
Defect Detection for Metal Base of TO-Can Packaged Laser Diode Based on Improved YOLO Algorithm
Defect detection is an important part of the manufacturing process of mechanical products. In order to detect the appearance defects quickly and accurately, a method of defect detection for the metal base of TO-can packaged laser diode (metal TO-base) based on the improved You Only Look Once (YOLO) algorithm named YOLO-SO is proposed in this study. Firstly, convolutional block attention mechanism (CBAM) module was added to the convolutional layer of the backbone network. Then, a random-paste-mosaic (RPM) small object data augmentation module was proposed on the basis of Mosaic algorithm in YOLO-V5. Finally, the K-means++ clustering algorithm was applied to reduce the sensitivity to the initial clustering center, making the positioning more accurate and reducing the network loss. The proposed YOLO-SO model was compared with other object detection algorithms such as YOLO-V3, YOLO-V4, and Faster R-CNN. Experimental results demonstrated that the YOLO-SO model reaches 84.0% mAP, 5.5% higher than the original YOLO-V5 algorithm. Moreover, the YOLO-SO model had clear advantages in terms of the smallest weight size and detection speed of 25 FPS. These advantages make the YOLO-SO model more suitable for the real-time detection of metal TO-base appearance defects
Influence of Test Parameters on the Evaluation of Chocolate Silkiness Using the Tribological Method
Silkiness is an extremely important attribute in high-end chocolate, and tribology is one of the commonly used methods of evaluating certain properties of the relevant food. In this study, based on three commercial chocolates of the same brand, the silky sensation was assessed by means of the professional sensation evaluation method. Artificial saliva was employed to obtain the mixed solutions with different chocolates, and their viscosity and coefficient of friction (CoF) were measured under different test parameters. The correlation of chocolate silkiness with the viscosities and average CoFs (aCoFs) are later discussed. The results showed that the silkiness of the three chocolates were negatively correlated with cocoa concentration and weakly correlated with viscosity. As the chocolate percentage decreased, the aCoF of the mixed solutions decreased, but the aCoF of the mixed solutions increased in relation to the cocoa concentration. In combination with the correlation coefficient of chocolate silkiness with the aCoFs, it was considered that 75% chocolate solutions using the Two-PDMS pair could be representative of the silkiness characteristic in oral processing at suitable operated parameters. The study results provide an insight into the rapid evaluation and development of similar attributes of high-end food
Preparation of homogeneous sub-micron cerium oxide polishing powder
To obtain homogeneous submicron cerium dioxide (CeO2) polishing powder, CeO2 was synthesized by solvothermal reaction using cerium nitrate (Ce(NO3)3·6H2O) as cerium resource and alcohol-water mixed solution as solvent. The phase composition and morphology of CeO2 were characterized by X-ray diffraction (XRD), laser particle size analyzer and scanning electron microscope (SEM). The formation process of CeO2 particles was analyzed by changing the concentration of Ce3+ and alcohol-water ratio. The synthesized CeO2 was used for chemical mechanical polishing (CMP) Si-face of 6H-SiC. The polishing characteristics were tracked by atomic force microscopy (AFM) and electronic balance. The results indicates that when the Ce3+ concentration is 0.10 mol/L and alcohol/water volume ratio is 3∶1, the as-prepared particles have regular morphology, moderate particle size and uniform particle size distribution. After polished by using the as-prepared CeO2, the Ra of wafer surface reached 0.243 nm and the dMRR 287 nm/h. The as-prepared CeO2 can be used for chemical mechanical polishing
Investigation of Protein Adsorption Mechanism and Biotribological Properties at Simulated Stem-Cement Interface
Molecular Dynamics Simulation Study on the Interactions of Mixed Cationic/Anionic Collectors on Muscovite (001) Surface in Aqueous Solution
In this study, the adsorption mechanisms of dodecylamine hydrochloride(DDAHC), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate(SDBS), and their mixed anionic/cationic collectors at ten different molar ratios on a muscovite (Mcv) surface in neutral aqueous solution were assessed by molecular dynamics simulations (MDS). According to the snapshot, interaction energy, radial distribution function (RDF), and density profile between the Mcv surface and collector molecules, the individual DDAHC collector was an effective collector for the flotation of Mcv. The molar ratio of anionic/cationic collectors was determined to be an essential factor in the flotation recovery of Mcv. The DDAHC collector was involved in the adsorption of the mixed anionic/cationic collectors on the Mcv (001) surface, whereas SDS and SDBS collectors were co-adsorbed with DDAHC. The mixed cationic/anionic collector showed the best adsorption on the Mcv surface in a molar ratio of 2. Additionally, SDBS, which has one more benzene ring than SDS, was more likely to form spherical micelles with DDAHC, thus resulting in better adsorption on the Mcv surface. The results of micro-flotation experiments indicated that the DDAHC collector could improve the flotation recovery of Mcv in neutral aqueous solution, which was in agreement with MDS-derived findings. In conclusion, DDAHC alone is the optimum collector for Mcv flotation under the neutral aqueous conditions, while the mixture of DDAHC and SDBS collectors (molar ratio = 2:1) exhibits the similar flotation performance
Improving the Tribological Performance of Phosphate-Bonded Coatings Reinforced by Carbon Fiber/Graphene Oxide
To enhance the interfacial bond strength of carbon fiber
(CF),
graphene oxide (GO) was grafted onto the CF surface byγ-aminopropyl
triethoxysilane, and CF modified with GO (CF-GO) was added into the
phosphate-bonded coating as a reinforcement to improve the tribological
properties of the coating. In addition, the evolution of the physiochemical
structure of CF before and after the modification was investigated
by Fourier transform infrared spectroscopy, X-ray diffraction analysis,
X-ray photoelectron spectroscopy, and scanning electron microscopy.
The results show that GO and CF are chemically bonded together, and
the CF surface becomes rough due to the presence of GO, enhancing
mechanical engagement to improve the interfacial bond between CF-GO
and the coating matrix, which is improved by the CF pull-out test.
Tribological tests were conducted to investigate the wear behavior
of the coating. The friction coefficient of the coating decreases
with the increase of CF-GO. Besides, the wear rate of the coating
shows similar trends with the addition of CF-GO. The addition of 15
wt % CF-GO has reduced the coefficient of friction and wear rate of
the coating by approximately 18 and 40%, respectively, when compared
to those of the coating without GO-CF. The related mechanisms are
also clarified