Papers by Keyword: Surface

Abstract: Superior quality dental implant surface was achieved by an air-isolation technique of sand-blasted, large-grit, acid-etched (SLA) treatment. The experiment was conducted in an air-isolation conditions of sand-blasting and acid-etching. The surface microstructures, chemical compositions, and bioactive properties of treated Ti-6Al-4V implants were examined using scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and simulated body fluid (SBF) immersion test. Research results revealed that the air-isolation SLA (A-SLA) treated implant, which was coated with SBF thin liquid film and sandblasted for 20 s, exhibited better hydroxyapatite (HA)-inducing ability owing to its favorable wettability.

Abstract: There is a relationship between pores and inclusions. As hypothesis goes, inclusions have an affinity to gather inside the pores and form clusters. Focus of this paper is how solidified dendritic structure affects the pressure field in the liquid and pore precipitation in austenitic stainless steel. Steel sample is a continuously cast bloom. Temperature profile and width of the mushy zone of the strand is modeled according to a constant temperature at the strands surface. Thermal analysis has been performed with differential thermal analysis (DTA) and differential scanning calorimeter (DSC). Dendrite arm spacing (DAS) is measured with light optical microscopy (LOM) and scanning electron microscopy (SEM). DAS is represented as the weight average of the distance between parallel sets of primary dendrite stems. Pressure field is calculated based on Darcys law. Pore formation is described through segregation of the gas components and pressure field in the liquid.

Abstract: We controlled morphologies of F-doped SnO₂ (FTO) thin films via an electrochemical method. To obtain rough and porous surface of the FTO thin films, a potentiostat/galvanostat was used. Field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were employed to demonstrate the morphological changes of FTO surface. The electrical and optical properties of the FTO thin films were analyzed using Hall effect measurement system and UV-vis spectrophotometry. Also, morphology controlled the FTO thin films would be applied to dye-sensitized solar cells.

Abstract: In this study, shell powder was modified by sodium stearate surface modifier for improving the compatibility of SP with polymer materials. The surface modifiers influence on the physical and chemical properties of SP were studied by scanning electron microscope (SEM), fourier infrared spectrum (FT-IR), surface contact angle meter, XRD diffraction analysis meter and other modern instruments and analysis method. The results showed that the surface modifier was successfully coupled to the shell powder surface. After surface modifier modification, the interfacial compatibility of the shell powder with polymer materials was effectively improved. The contact angle of shell powder surface increased from 73.5 ° to 110.8 ° , along with the dosage of sodium stearate surface modifier was 4.0%. All results suggested that modified shell powder is promising for using as a reinforcement filler in polymer materials.

Abstract: Laser surface hardening is an advanced method of surface treatment of structural steels with a great potential for wide industrial applications. The technology is quite new and so, investigations have to be performed in order to gain a comprehensive knowledge about effects on microstructure, hardness, surface properties of treated materials, but also mechanical an particularly fatigue properties. Concerning fatigue resistance of material treated with this technology, results and knowledge recently published in the literature indicate that fatigue resistance can be either reduced or increased, even considerably, depending on numerous parameters of basic material, laser hardening parameters etc. This contribution contains results of a partial study of effect of laser hardening of relatively small specimens on fatigue resistance of 42CrMo4 steel. Two different parameters of the treatment were used, namely two speeds of laser beam on the material surface at constant beam energy. Unlike the lower speed, when fatigue resistance was slightly reduced, higher speed of laser beam resulted in a slight increase of fatigue resistance and fatigue limit. The results are discussed considering an occurrence of residuals stresses. Key words: Laser hardening, residual stress, lifetime, fatigue, fracture, microstructure, surface

Abstract: The paper deals with the problematic of contact comfort as a part of body conscious design/ human-centred design. Contact comfort consist of a combination of balanced surface temperature, heat transmission, surface roughness, surface elasticity/hardness, sorption activity of the surface in terms of vapour/fluids absorbance, sorption activity of the surface in terms of absorbing the external moisture (e.g. sweat or humidity of air/its condensates), having control over body position, possibilities of maintenance and visual comfort connected with cultural background of users, individual mental and physical setting that is creating overall feeling of comfort. All these parameters are measurable and it is possible to optimize them with an aim to get good solutions that are providing higher contact comfort.Roughness is extremely important for overall feeling of contact comfort it has direct relation also to the other features. The current paper presents also the methodology and results of the pilot study of contact comfort. .Different wood based materials and wood species with different types of surface finishing in comparison with other materials were investigated by using a test chair.

Abstract: Epitaxial layers grown on mechanically lapped 4H-SiC (0001) substrates were analyzed by using scanning ion microscopy (SIM), photoluminescence (PL) mapping and transmission electron microscopy (TEM). Even in the use of substrates with standard nitrogen concentration of 1.3 × 10¹⁹ cm^-3, double Shockley-type stacking faults were observed to be formed in the epitaxial layer from the interface between the epitaxial layer and the substrate without any external stresses. Surface damaged layer seems to cause the formation of not only 2SSFs but also threading edge dislocation (TED) half-loops during epitaxial growth.

Abstract: In order to obtain the maximum amounts of amino functional groups with low temperature ammonia plasma surface treatment on PAN-based carbon fiber, the influence of processing temperature and time were researched in this paper. By using X-ray photoelectron spectroscopy (XPS) method, the-NH₂(-NH)/ C-C atomic ratio of untreated and treated fiber was analyzed. Results show that processing temperature is a key factor as intensity of the N1s peak increases gradually while processing temperature improves, furthermore, when temperature is 175°C, the most intensity of the N1s peak is obtained. Low temperature ammonia plasma surface treatment method has given a new approach to surface functionalized treatment of carbon fiber.

Abstract: The diffusion bonding of Ti to Ti, Ti-Cu alloy at different temperatures ranging from 673 K to 923 K under an applied stress of 100 MPa for 1 h was studied. The observation of the microstructure reveals that sound joints between the Ti-Ti and dissimilar titanium/Copper metals sheet were successfully joined by diffusion bonding process. Ti-Cu alloy without any pores or cracks can be achieved through diffusion bonding at temperatures over 873 K under the applied stress of 100 MPa for 1 h. The bond is composed of the zones, and its width increases with the increase of bonding temperature. The Micro hardness at the interface of joints bonded under different conditions was evaluated through Micro hardness testing and the fracture mode was analyzed by SEM observation.

Abstract: This paper describes a method for visual reconstruction and analysis of the surface of earthworm in AVS/Express, Advanced Visual System's new visualization development tool. The digital measurements of surfaces of the earthworm were carried out using a three-dimensional laser scanner. Detailed information on the point clouds, the scanning digital data of the surface of the earthworm were obtained by importing and analyzing those point clouds in AVS/Express. Methods and results presented in this paper proved to be potentially useful for analyzing the feature of biological prototype, optimizing the mathematical model and affording deformable physical model to bionic engineering, this would have significant implications to the research of biological coupling theory and technological creation in bionic engineering.