Inhibition of decoherence due to decay in a continuum

We propose a scheme for slowing down decay into a continuum. We make use of a sequence of ultrashort 2pi pulses applied on an auxiliary transition of the system so that there is a destructive interference between the two transition amplitudes--one before the application of the pulse and the other after the application of the pulse. We give explicit results for a structured continuum. Our scheme can also inhibit unwanted transitions.     

OH sensor based on ultraviolet, continuous-wave absorption spectroscopy utilizing a frequency-quadrupled, fiber-amplified external-cavity diode laser

The development of an all-solid-state cw laser system for optical absorption measurements of the OH radical in the UV spectral range is described. The tunable output of a 1064-nm external-cavity diode laser is amplified by use of a Nd:doped, double-clad fiber amplifier. The amplified near-IR radiation is frequency doubled by a periodically poled lithium niobate crystal and then quadrupled in a beta-barium borate crystal. The design and operation of the system and measurements of OH absorption in the (2, 0) band of the A(2)?(+)- X(2)? electronic transition are discussed.     

Some insights in the sonochemical preparation of cobalt nano-particles

The preparation of cobalt nano-particles from a solution of Co(CO)₃(NO) in n-decane under ultrasonication with a frequency of 20 kHz yielded cobalt particles of a size of ca. 5 nm. The presence of either silica or oleic acid in the solution reduced the particle size to ca. 3 and 2 nm, respectively. The resulting particle size is independent of the ultrasonication time, initial Co(CO)₃(NO) concentration, ultrasound intensity and solution temperature. It is postulated that bubble collapse generates multiple nucleation sites resulting in the formation of cobalt particles with a rather uniform particle size distribution.     

VEGFR-2 targeted cellular delivery of doxorubicin by gold nanoparticles for potential antiangiogenic therapy

We report a novel gold nanobioconjugate system that achieves targeted delivery of the small molecule drug doxorubicin to endothelial cells using anti-VEGFR-2 antibody conjugated gold nanoparticles (GNPs). The reported nanobioconjugate system combines the inherent ability of GNPs to undergo high levels of derivatization with the precision of antibody recognition of a cell surface antigen. Transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS) confirmed intracellular presence of the GNPs. Using a VEGFR-2 expressing cell line and a cell line that is negative for the receptor, in combination with competition assay we established the cell specific targeted delivery of the nanobioconjugate. The nanobioconjugate system described here may have potential drug delivery applications for antiangiogenic cancer therapy.     

An analysis of Y2O3:Eu thin films for thermographic phosphor applications

A comparative study of the luminescent properties of Y₂O₃:Eu³⁺ phosphor powders and thin films sputtered from targets prepared from combustion synthesized powders is reported. Thin films of (Y_0.96Eu_0.04)₂O₃ were deposited on silicon substrates. Films deposited at 600 °C had both monoclinic and cubic phases of Y₂O₃, which developed to an oriented cubic phase after annealing. Films and powders showed a linear dependence of the intensity of the ⁵D₇→⁷F₂ (611 nm) transition with temperature in the range 26-660 °C with an average rate of change of 1.8×10⁻⁴ °C⁻¹. The rate of change appears to be dependent on the Eu³⁺ concentration. This work shows that these thin films can be used as thermographic phosphors for remote temperature measurements.     

CARS methane spectra: Experiments and simulations for temperature diagnostic purposes

CARS laboratory experiments were done in the 2905–2925 cm⁻¹ range, in the vicinity of the ν₁ band of the methane molecule, for pressures ranging from 1 to 50 bar, and temperatures up to 1100 K. These experiments were carried out in order to retrieve the pressure evolution of the CH₄ spectrum, as well as to confirm its temperature dependance. After a brief recall on the theory used to compute pressure broadening coefficients and relaxation rates, we consider the ν₃ and ν₄ infrared bands of methane for benchmark calculations purposes. Next, we present recent experimental CARS spectra and calculated ones. Lastly, we discuss flame experiments as well as comparisons of temperature retrieval using N₂ and CH₄ as probe molecules.