Papers by Keyword: Nano

Abstract: Osteoporosis (OP) is a systemic metabolic disease identified with decrease of bone mineral density and deterioration of microstructure leading to fragility fractures in elderly. Boron (B) is assumed to stimulate osteoblasts. Hydroxyapatite (HAp) is clinically used to conduct bone regeneration and improves implant integration. Nano(n)-HAp expands the surface area for cell adhesion and may improve bone regeneration and tissue integration. The objective of this study was to examine the adhesion, proliferation and differentiation of B-n-HAp with mesenchymal stem cells (MSC’s). Human bone marrow derived MSC’s phenotype was assessed using scanning and transmission electron microscopy after combining with B-n-HAp and n-HAp. Cell adhesion and proliferation potential of these ceramics was examined with the real time cell analysis (xCELLigence, Roche Applied Science and ACEA Bioscience, USA) system and adipogenic-osteogenic differentiation was analyzed with morphological and quantitative methods. MSC’s adhesion and proliferation rates (cell index, 4.50) were higher than controls (cell index, 4.00). Adipogenic and osteogenic differentiation potential of MSC’s remained unchanged in the presence of B-n-HAp ceramics. In conclusion, B-n-HAp stimulates MSC’s adhesion, proliferation and differentiation and has a potential to regenerate bone tissue.

Abstract: Lizardite were synthesized by hydrothermal reaction in an Fe³⁺ doped solution/environment using nanometer SiO₂ and MgO as precursors. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR). The results show that: the synthetic samples are lizardite with a thickness ranging from 60 nm to 200 nm in the temperature range 200°C~230°C.

Abstract: Porous concrete pavement is being used as one of the solution to decrease the storm water runoff by capturing and allowing rain water to drain into the land surface. The main problem of porous concrete pavement is the strength itself. The objective of this paper is to review the use and performance of nanosilica in porous concrete pavement. From the literature review of the previous research, it was found that the conventional porous concrete pavement doesn't has good strength for pavement purpose. An addition of nanomaterial will improve the physical and chemical properties of the porous concrete pavement.

Abstract: Nano agnesium phosphate (n-MP) was synthesized using a chemical precipitation method. The results revealed that the synthesized n-MP with the mean particle size of 79 nm and could be degradable in PBS solution with the weight loss was 70.4w% after soaking for 60 days. The extracts of n-MP caused no cytotoxicity on L929 cells, revealing good biocompatibility, which satisfied the relevant criterion on biomaterials.

Abstract: The paper is concerned on the properties of the new ideal circuit element, a memristor. We proposed memristor with nanothin three layers of Pt/ TiO_2-x/TiO₂/TiO_2+x/Pt sandwiched structure in this paper,based on study of the working principles of HP memristor. As the new TiO_2+x layer and its expansion effect,the switching speed of the new structure memristor mentioned would be faster. The paper gives the test result and mechanism of the new structure memristor, such as characteristic analysis results of Pt nanowire, memristor, repetitiveness and V-I characteristic hysteretic curve of three layers memristor by using semiconductor tester.

Abstract: In this work, we report two methods to fabricate the nanophase-change memory: (1) electron beam lithography (EBL) using the positive resist ZEP-520A followed by phase change material deposition and lift-off processes, (2) EBL using the negative resist hydrogen silsesquioxane (HSQ) followed by reactive ion etching (RIE) after phase change material deposition. For the former method, the optimized exposure dosage is around 40 μC/cm² and the finest nanowire is about 80 nm in width. On the other hand, the latter method shows that the finest nanowire can be as small as about 15 nm in width after RIE process and the optimized exposure dosage is around 2.0 mC/cm². In this case, collapse-preventing pattern becomes necessary for fabrication of such a fine nanowire.

Abstract: The aims of this study are to fabricate Ti/APC-2 hybrid composite laminates with and without (W/WO) nanoparticles and investigate the mechanical properties of laminates with single-edged cracks due to both tensile and cyclic tests. The mechanical properties such as ultimate tensile strength and longitudinal stiffness of original composite laminates W/WO nanoparticles were first obtained from the static tensile tests. However, the load-displacement diagrams were plotted for the crack laminates. The constant stress amplitude tension-tension cyclic tests were conducted to receive the S-N curves and fatigue data. The ultimate strengths for both Ti/APC-2 composite laminates W/WO nanoparticles were very close at varied crack length. Ti/APC-2 cross-ply nanocomposite laminates had better fatigue resistance than that of laminates without nanoparticles. The longer the crack length is, the more their properties are reduced. Also, the values of fracture toughness of both hybrid cracked laminates W/WO nanoparticles were obtained by rule of mixtures and found acceptable. Finally, in predicting crack growth rate and residual life, instead of commonly used Paris Law for metals, the modified method was adopted for hybrid cracked laminates. The prediction is not satisfactorily acceptable, even if most results are in good agreement with empirical data.

Abstract: nanohydroxyapatite (n-HAP) was coated on to AZ31 magnesium alloy in order to reduce the surface corrosion rate and enhance the bio-compatibility. N-HAP was successfully coated by pulse electrodeposition technique. Morphology and composition of the coatings were investigated by scanning electron microscopy and X-ray diffraction methods, respectively. The corrosion behaviors of the coatings were studied by tafel polarization and impedance spectroscopy tests. Results demonstrated that the porosity of the nanostructure coating decrease in comparison with micro structure coating and therefore, corrosion resistance of AZ31 was improved significantly. Also, the adhesion of nanostructure coating was increased and thus it can be introduced as a suitable coating for body implants.

Abstract: The micro GEM is a position sensitive gas electron multiplier detector with high-density and regular arrangement of holes inside a insulation foil The new idea for decreasing the applied voltage with the same electric field and also get rid of the complexity of producing regular arrangement of micro holes, is the dimension reduction of the GEM to the range of nanometer. The proposed method for producing this nanostructure is anodization of the aluminium. The simulation results show that although the nanoGEM has typically less gain in comparison to micro GEM, but with applied voltages in order of few Volts, high gains can be achieve by multiple nanoGEMs. This novel idea which can be used for production of low voltage and portable position sensitive detectors has higher spatial resolution in comparison to commercial ones.

Abstract: In this work, we use 3D finite difference time domain (3D-FDTD) to calculate the plasmon resonance effect for a single silver hemisphere in which the palsmon line shape have distinct peaks when the particles are located on a glass substrate. The dependence of the resonance on hemisphere size and the ratio of height over radius are characterized, and it is found that the surface interface effect played an important role on the plasman resonace effect for a single silver hemisphere.