Advanced Materials Research Vol. 739

Abstract: This paper is proposed to analyze the power loss from leakage current in p-n junctions in case of non-uniform defects. The different geometry p-n junctions have been fabricated by a standard 0.8 micron CMOS technology. The diode fabricated by the ion implantation process with two different condition. The reverse current and voltage (I-V)characteristics at varied temperature of p-n junctions have been measured. The power loss coefficient can be extracted from the leakage current versus temperature. Form the derivative of leakage current with temperature, the power loss with prediction trend curve can be obtained.

Abstract: Base catalyzed sol-gel derived porous SiO₂ coatings are prospectively used as antireflective (AR) layer for encapsulating solar modules. In this paper, the properties of SiO₂ AR layers coated on solar glass by different dip-coating and annealing conditions are investigated and optimized. It is shown that the transmittance of the AR coating is affected by these preparation conditions which closely related to the thickness and surface morphology. As results, the SiO₂ coating had a better performance both in transmittance and adhesion when the dip-coating speed and the annealing temperature are 0.036mm/s and 300°C respectively. Further more, TMCS hydrophobic treatment was adopted to make the AR coating meet the demands of practical application.

Abstract: Several techniques of implant surface structuring have been used in the past to modify the surface of titanium and its alloys. We first investigated the adhesion property of human osteoblasts (MG-63) on femtosecond laser treated Ti-6Al-4V for application in dental implant. Two different kinds of surface structures were generated with varied laser fluence. (1) Laser-induced periodic surface structures (LIPSS) with a period on the sub-micron level. (2) Microscale peaks and troughs surface structures (MPTSS) with superimposed submicron and nanoscale features. According to the cell quantity and adhesion property of MG-63 on polished and structured samples, femtosecond laser treated Ti-6Al-4V with LIPSS may more suitable for applied in dental implant.

Abstract: We consider in this paper the Projective Computer Tomography (PCT) as an instrument for image reconstruction of objects with the internal simple discrete structure that consists of some separate elements inside of the homogeneous (or quasi homogeneous) substance in the considered domain. PCT consists in localization of intersections of prolongation of some known projections, obtained as images by some concrete tomography. Developed scheme is constructed as algorithms and MATLAB program package, which quality and rapidity is demonstrated on simulated numerical examples.

Abstract: Nanocomposites based on polypropylene (PP), polyamide 66 (nylon 66) and PP/nylon 66 immiscible blends containing 5wt% TiO₂ nanoparticles were prepared via melt compounding. The influences of TiO₂ on the rheology of nanocomposites and blend nanocomposites were investigated. Scanning electron microscopy results revealed the size of inclusion phase was smaller in PP/PA 66/TiO₂ 75/25/5 comparing to the PP/PA 66/TiO₂ 25/75/5. A co-continuos phase was observed at 50/50 composition. Melt dynamic rheology showed that the moduli of the PP increased with incorporation of TiO₂ nanoparticles at the moderate frequencies, while this effect was reverse in PA 66 nanocomposite. Several rheological and rheo-morphological models were used for prediction of rheological parameters. The well-known models for rheology of suspensions proposed by Einstein, Roscope and Eilers-van Dijck were successful for prediction of viscosity of PA nanocomposite. Palierne model was fitted to the experimental values especially for the: PP/PA 66/ TiO₂ 25/75/5 blend nanocomposite.

Abstract: The effect of several types of nanoparticles on the rheological properties of polycarbonate (PC) was compared. Four polycarbonate nanocomposites containing 5 wt% of layered silica (SiO₂), Iron oxide (Fe₃O₄), Iron oxide (α-Fe₂O₃), cupric oxide (CuO) nanoparticles were prepared via melt compounding at 260 °C. Compression molded samples were prepared and the dynamic rheological properties of the nanocomposites were investigated. The incorporation of the nanoparticles increased the storage modulus and consequently decreased the damping factor. In the Cole-Cole plot, PC filled layered silica and Fe₂O₃ nanoparticles showed more semi-circle pattern comparing to that of other nanocomposites implied more compatibility between PC and layered silica and also Fe₂O₃ nanofillers. While other nanocomposites showed more deviation from this pattern. Rotational mode in rheological studies showed that at low shear rate the viscosities of nanocomposites are higher than that of pure Polycarbonate. While at higher shear rate the viscosity of filled samples tend to approach the viscosity of pure PC.

Abstract: The phase diagram was experimentally determined by measuring the melting process for butylated hydroxytoluene (BHT)/paracresol system with differential scanning calorimeter (DSC). It was confirmed that this system is a binary eutectic system. Experimental results showed that the binary system is completely miscible in the liquid state and completely immiscible in the solid state. The compositions of the eutectic point were 28.37/ 71.63(BHT /Paracresol, mass percent) in the T-X phase diagram. The phase diagram data was modeled by different models, and it was found that Wilson model give better description of the experimental data.

Abstract: Parallel extrusion is a combined extrusion process for forming round-fin heat sink on thick metal sheets. In this paper, the parallel extrusion has been applied to manufacture the round-fin heat sink in the automotive lighting. Numerical simulations on the round-fin heat sink forming using the software DEFORM were carried out. The tooling structure with counterpressure on the heat sink formation was investigated. The results show that the tooling structure with counterpressure is helpful to the formation of round-fin heat sink, which not only ensures the height of each round-fin on the heat sink is uniform but also retards the initiation of flow-through on the reverse side of round-fin. In addition, the experiments of press forging process were conducted to validate the finite element analysis, it is shown that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin, and the simulation results are in good agreement with the experimental data.

Abstract: In this work, B₄C porous ceramics reinforced alumium composite was fabricated by the sponge impregnant method and pressureless infiltration technique. The wettability of aluminum on B₄C, the component and the wear resistance of the composite were studied .The result indicates that the infiltration temperature is determined 1200 centigrade and there are mainly Al, B₄C, Al₃BC , no AL₄C₃ in the experimental composite, the wear resistance of B₄C/AL composite is 25 to 30 times higher than that of the alumium.

Abstract: Selecting effective xenon adsorbents is important for preventing significant global nuclear proliferation. The adsorption capacity of coconut shell activated carbons (SAC),zeolite 10X,zeolite 5A, zeolite 13X were researched and the Xenon adsorption of the coconut shell activated carbon modified by KOH(SAC/KOH-1 and SAC/KOH-2) were compared in this paper. The factors of temperature and flow rate that influenced the dynamic adsorption of xenon by 10X were discussed. The order of the Xenon adsorption capacity is as follows: zeolite 10X, SAC/KOH-2, SAC/KOH-1, SAC, zeolite 13X, zeolite 5A.