Search results for " density"
showing 10 items of 2709 documents
Immobilization of BMP‐2, BMP‐7 and alendronic acid on titanium surfaces: Adhesion, proliferation and differentiation of bone marrow‐derived stem cells
2019
This study analyzed the influence of titanium (TiO2 ) surface modifications with two osteogenic proteins (BMP-2, BMP-7) and an anti-osteoclastic drug (alendronic acid [AA]) on sandblasted/acid-etched (SLA) and plain TiO2 (PT) on cell adhesion, proliferation and differentiation (alkaline phosphatase [AP] and osteocalcin [OC]) of bone-marrow derived stem cells (BMSCs) after 1, 3 and 7 days in-vitro. Initially, AA surfaces showed the highest cell number and surface coverage. At day 3 and 7, BMP and AA-modified surfaces exhibited a significantly enhanced cell growth. For proliferation, at days 3 and 7, an enhancement on BMP-2, BMP-7 and AA-surfaces was seen. At day 7, SLA also showed a higher p…
Nanogoniometry with scanning force microscopy: a model study of CdTe thin films.
2007
In this paper scanning force microscopy is combined with simple but powerful data processing to determine quantitatively, on a sub-micrometer scale, the orientation of surface facets present on crystalline materials. A high-quality scanning force topography image is used to determine an angular histogram of the surface normal at each image point. In addition to the known method for the assignment of Miller indices to the facets appearing on the surface, a quantitative analysis is presented that allows the characterization of the relative population and morphological quality of each of these facets. Two different CdTe thin films are used as model systems to probe the capabilities of this met…
Energy models for fatigue life estimation under uniaxial random loading. Part I: The model elaboration
2001
The paper contains analysis of the energy models for the fatigue life assessment under uniaxial stress state. From the simulation tests it appears that taking into account the stress and strain signs during determination of the energy density allows one to distinguish the strain energy density at the tension and compression path. Under random loading with the zero expected values for Gaussion processes it leads to the centered stochastic process. A new (basic for damage cumulation) material characteristic can be easily determined by rescaling the widely used standard stress and strain characteristics of cyclic fatigue. A new model of the fatigue life determination has been proposed. This mo…
Variable magnification digital in-line holographic microscopy
2019
We present a new layout providing different magnifications and resolution capabilities in lensless imaging by using an electrically tunable lens (ETL). Experimental validation is reported using a resolution test target and prostate cancer cells.
Particle suspension in top-covered unbaffled tanks
2010
Abstract Unbaffled stirred tanks are seldom employed in the process industry as they are considered poorer mixers than baffled vessels. However, they may be expected to provide significant advantages in a wide range of applications (e.g. crystallization, food and pharmaceutical processes, etc.), where the presence of baffles is often undesirable. In the present work solid–liquid suspension in an unbaffled stirred tank is investigated. The tank was equipped with a top-cover in order to avoid vortex formation. A novel experimental method (the “steady cone radius method”, SCRM) is proposed to determine experimentally the minimum impeller speed at which solids are completely suspended. Experime…
X-ray imaging of the heating zone of non-normal incidence pumped XRL plasma
2006
Soft x-ray emission, above 600 eV, from a grazing incidence pumped Ni-like Mo x-ray laser (GRIP-XRL) [1] plasma was investigated. Using a pinhole camera looking along the target surface, perpendicular to the direction of the XRL emission, spatially-resolved information was obtained with a resolution which was limited only by the pinhole size of 10 μm. The relative distance from the target surface to the plasma zone heated by th e picosecond pulse was investigated for different GRIP angles, energy ratios and delays between the plasma producing and the plasma heating pulses.
Ab Initio Simulation of Attosecond Transient Absorption Spectroscopy in Two-Dimensional Materials
2018
We extend the first-principles analysis of attosecond transient absorption spectroscopy to two-dimensional materials. As an example of two-dimensional materials, we apply the analysis to monolayer hexagonal boron nitride (h-BN) and compute its transient optical properties under intense few-cycle infrared laser pulses. Nonadiabatic features are observed in the computed transient absorption spectra. To elucidate the microscopic origin of these features, we analyze the electronic structure of h-BN with density functional theory and investigate the dynamics of specific energy bands with a simple two-band model. Finally, we find that laser-induced intraband transitions play a significant role in…
Single molecule imaging using a highly confined optical field at a triangular aperture
2005
We demonstrate that scanning near-field optical microscopy based on a probe with a triangular aperture is capable of imaging single fluorescent molecules with an optical resolution of 30 nm. Numerical simulations agree well with experiment.
Detection of defects buried in metallic samples by scanning microwave microscopy
2011
This paper reports the local detection of buried calibrated metal defects in metal samples by a new experimental technique, scanning microwave microscopy. This technique combines the electromagnetic measurement capabilities of a microwave vector network analyzer with the subnanometer-resolution capabilities of an atomic force microscope. The network analyzer authorizes the use of several frequencies in the range 1--6 GHz, allowing three-dimensional tomographical investigation, which is useful for the detection of bulk defects in metal materials.
Dynamic doping in bright and stable light emitting electrochemical cells.
2013
By using fast current density and luminance versus voltage (JL-V) analysis the device operation of sandwiched light emitting electrochemical cells (LECs) during their normal voltage driving operation mode is studied. In LECs the application of a voltage results in the movement of ions changing the state of the device, as a result the JL-V scans need to be performed fast and meet certain conditions to be meaningful. Space-charge limited current behavior is observed once the injection barriers are overcome. The increase of the current density after this point imply that the effective thickness of the devices is reduced which indicates the formation of more conductive regions adjacent to the e…