We report on how to increase transmittance of a 0.2 mm thick polycarbonate (PC) film by periodic subwavelength anti-reflection structures in the visible spectral range. Subwavelength anti-reflection structures like mo...
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We successfully engineered Si nano-columns with different cross-sectional geometries by e-beam evaporation with an angle between source and substrate. The Si nano-columns were grown as pillars with square, triangle an...
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We successfully engineered Si nano-columns with different cross-sectional geometries by e-beam evaporation with an angle between source and substrate. The Si nano-columns were grown as pillars with square, triangle and linear cross sections in in-plane. Mesenchymal stem cells (MSCs) isolated from the bone marrow stroma of young adult rats were cultured on these different Si nanosurfaces. We found that the behaviour of MSCs highly depended on the geometry of nano-topography so that mesenchymal stem cells were differentiated and induced CaP precipitation on square-cross-sectional Si nano-columns without growth factor in the culture medium.
A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN su...
A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN substrates rests in the application of halide vapor phase epitaxy (HVPE) to produce GaN films at high growth rates. In this paper, we describe the growth of thick GaN films via the HVPE technique on (0001) sapphire and (111) Si substrates. At a temperature of 1030°C, films are grown at rates between 70 and 90 μm/hr, yielding total thicknesses exceeding 200 μm on sapphire. DCXRD measurements of GaN/sapphire indicate FWHM values less than 220 arcsec on 180 μm thick films. Room temperature PL measurements of GaN/sapphire indicate strong emission at 3.41 eV, with a FWHM value of 65 meV. Moreover, no detectable deep level emission was found in room temperature PL measurement. Under optimized conditions, films are morphologically smooth and optically clear. The GaN morphology appears to be a strong function of the initial nucleation conditions, which in turn are strongly affected by the partial pressure of GaCl. HVPE growth on (111) Si substrates is accomplished using an AlN MOVPE buffer layer.
In most of the ternary (and higher-order) ferromagnetic shape memory alloys (FSMAs) with compositions close to the A2BC stoichiometry, the austenite phase exhibits L21-type ordering. Recent investigations of the Co-Ni...
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In most of the ternary (and higher-order) ferromagnetic shape memory alloys (FSMAs) with compositions close to the A2BC stoichiometry, the austenite phase exhibits L21-type ordering. Recent investigations of the Co-Ni-Ga FSMA system, however, suggest that the austenite phase has B2-type ordering, although definite confirmation remains elusive. In this work, we present a theoretical investigation of the effect of configurational order on the magnetic properties of the ordered (L21) and disordered (B2) FSMA Co2NiGa. Through the use of calculations based on density functional theory, we predict the structural and magnetic properties (including magnetic exchange constants) of ordered and disordered Co2NiGa alloys. We validate our calculation of the magnetic exchange constants by extracting the Curie temperatures of the austenite and martensite structures and comparing them to experimental results. By constructing a q-state Potts magnetic Hamiltonian and through the use of lattice Monte Carlo simulation, we predict the finite-temperature behavior of the magnetization and magnetic susceptibility as well as the magnetic specific heat and entropy. The role of configurational order in the magnetic properties of the phases involved in the martensitic phase transformation is discussed, and predictions of the magnitude of the magnetic contributions to the transformation entropy are presented. The calculations are compared to experimental information available in the literature as well as experiments performed by the authors. It is concluded that in FSMAs magnetism plays a fundamental role in determining the relative stability of the austenite and martensite phases, which in turn determines the martensitic transformation temperature Ms, irrespective of whether magnetic fields are used to drive the transformation.
Lithological information, rock mass fracture data and discontinuity shear strength obtained through field investigations have been used to conduct block theory analyses for the rock slopes that exist in the dam site t...
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The equations exist in the literature to estimate corrected mean trace length and corrected two dimensional density of a discontinuity set using area sampling technique are critically reviewed. A shortcoming that exis...
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The multi-luminophore lifetime determination (MLD) technique uses a simple window sum correction to calculate the true lifetime of two temporally-distinct luminophores using time-domain techniques. This method offers ...
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ISBN:
(纸本)9781424492909
The multi-luminophore lifetime determination (MLD) technique uses a simple window sum correction to calculate the true lifetime of two temporally-distinct luminophores using time-domain techniques. This method offers advantages over traditional fitting methods because it can quickly calculate lifetime for optimal use in applications which require the ability to monitor dynamic changes, such as multi-analyte sensing. Measurement error can be reduced if sampling parameters such as window width are chosen appropriately.
Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. A...
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Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. At varying peak fluences morphology is seen where the tubes are ejected from the substrate or formed into long, parallel structures of SWNT’s. These structures have been created on both glass substrates and carbon grids. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) investigation of the structures reveal that they are composed of bundled nanotubes typically 400 nm – 1 micron long. Large-area laser patterning of the film allows for structuring of the film without detrimental decreases in conductivity.
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