Advanced Materials Research Vols. 47-50

Abstract: Dental porcelain fused to metals (PFM) is one of the most widely applied restoration material, because of its excellent esthetics, biocompatibility and wear resistance [1, 2]. In the literature of specialty (dentistry) there is not made a clear distinction between porcelain and ceramic, while referring to ceramics as being all these materials derived from mixtures of metallic oxides, being in opposition with metal alloys [3-5]. The aim of this study was to obtain and characterize dental porcelains, dentine type, in the following oxide system: SiO2-K2O-Al2O3-Na2O-B2O3-MgOCaO, reinforced with nanometric particles of monoclinic zirconia. The method selected for the preparation of the porcelain powders is through solid-state reactions.

Abstract: The aim of the study was the synthesis and characterization of bioactive osteoinductive glasses, in the SiO2 – CaO – P2O5 system. In order to maintain the bioactive character of bioglasses, for SiO2 contents higher than 60%, the sol – gel method was used for preparation. On the obtained powders, thermal, grain size and X - ray diffraction analysis were performed. The X - ray diffraction emphasized the formation of phosphate phases, whose proportion decreases as the silica content is increased. Later, the powders were thermally treated at temperatures between 1000 and 14000C, the phase composition evolution being monitored through XRD analysis. On the powder suspensions in physiological serum, the evolution of pH was investigated, in order to establish the chemical stability. The behavior of the obtained powders in physiological medium was studied, by immersing samples in simulated body fluid and excerpted after different periods of time.

Abstract: Extrusion screw that is used on market of present extrusion molding catapult is divided by single-axle extrusion screw and multi-axles extrusion screw. Simulation technique of screw that is used in extrusion molding has become so far various. Consist of that analyze third dimension model and that analyze two-dimension model but most Analysis that display dynamic characteristic of screw inside of heat and flow in detail was not until present. Transfer of polymer site that typical single-axle extrusion screw that is analysis target of this treatise is mixed in most melting state is good, but has some controversial points. First melting transfer of balance that is not done difficult. Second melting causes effect that weaken mechanical special quality of screw by power excessive last month if heighten the screw speed to increase amount of done balance. Third Screw dynamic characteristic symptoms by thermal expansion that happen in screw of heater is fallen.

Abstract: Importance on the detection of corrosion-related defect is undeniable from the fact that it can prevent significant economic loss and enhanced safety in mechanical equipments, pipes, ships, bridges, and other applications. Conventionally researched measurement methods for defect and thinning from corrosion are acoustic emission, EMAT using ultrasound, laser induced ultrasound, etc. However, these non-destructive testing methods have the shortcoming of accessibility to on-site. For instance, EMAT should be close to several millimeters to generate magnetic field in structure. For laser application, it can be applied to remote non-destructive testing, but some defect might not be possible to be detected by the surface condition of structure. In this study, infrared thermography camera is utilized to determine the degree of corrosion on paint-coated metal. In addition, fundamental researches to develop corrosion detection system for on-site metallic structure are conducted to provide the applicability of IR camera and possibility of thermal analysis method.

Abstract: Ultrasmall superparamagnetic iron oxide nanoparticles (USPION) as magnetic resonance imaging were synthesized through a sonochemical co-precipitation method with poly (ethyleneimine) (PEI). The size of the USPION was controlled by poly (ethyleneimine) (PEI) contents, ultrasonic exposure time, and Na4OH concentration. The characteristics of PEI-USPION were studied by X-ray diffractometry, magnetic property measurement system, scanning electron microscopy, transmission electron microscopy, and particle size analysis. The PEI-USPION had an average size of 5~10nm with a narrow size distribution, a perfect magnetite crystal structure, and high saturation magnetization.

Abstract: Ultra-small and well dispersed silver nanoparticles were prepared by mixing AgNO3 in PEI (polyethylenimine) solution. Particle size analysis and transmission electron microscopy confirmed that the average diameters of PEI/silver nanoparticles are 20-40 nm. The ultra-small silver nanoparticles had an antimicrobial activity in the aqueous solution at the concentration over 0.0105% by M.I.C test. Suggestively, the PEI/silver nanoparticles have potentials for development of wound dressings.

Abstract: The Fe50Co50 magnetic films were prepared by magnetron sputtering onto glass substrates. The structural and magnetic properties of the films were investigated as a function of annealing temperature and annealing time. It is found that the films have the better crystallization orientation after annealing. The in-plane coercivity Hc reduces with increasing annealing temperature and annealing time. Coercivity reaches the minimum in the sample annealed at 600°C for 2h. Meanwhile, the saturation magnetization Ms increases with increasing annealing temperature as a whole. A scanning probe microscope was used to scan surface morphology and magnetic domain structures. After annealing, the domain size becomes larger and the contrast of domains increases.

Abstract: The subsidence rate of nanometer particles in liquid is determined by their Brownian movement, liquid drag force and gravity. The paper utilized the relation between temperature and the Brownian movement that the Einstein’s Brownian motion equation reveals. One new method for temperature measurement is proposed which based on the subsidence rate of nanometer particles. The Einstein’s classical theory can connect with contemporary nanometer technology, it have new application.

Abstract: Iron-doped titanium nitride films deposed on glass substrates were prepared by magnetron sputtering technique. X-ray diffraction (XRD) was employed to analyze the phases existed in the films. Investigations have shown that as-deposited films were XRD-amorphous, and the TiN phase was formed in the film after additional annealing. It was found that iron-doped TiN films preserved the same crystal structure as TiN. The ferromagnetic properties of iron doped TiN films have been measured using vibrating sample magnetometer (VSM), and the electric resistances of the films were also determined by IR four-probe methods. The experiment results proved that the iron-doped TiN films possessed ferromagnetic property with low electric resistance at room temperature. It was investigated that the saturation magnetization was about 2.21×108 A/m, the coercivity about 23 kA/m, and the electric resisitivity 1.401×10-6 3•m for typical Fe-doped-TiN-films sample.

Abstract: Objectives: This report presents toxicological profile available on a superparamagnetic iron oxide (SPIO) nanoparticle in vivo.