61 research outputs found
Vortex solitons in dispersive nonlinear Kerr type media
We have investigated the nonlinear amplitude vector equation governing the
evolution of optical pulses in optical and UV region. We are normalizing this
equation for the cases of different and equal transverse and longitudinal size
of optical pulses, of week and strong dispersion. This gives us the possibility
to reduce the amplitude equation to different nonlinear evolution equations in
the partial cases. For some of these nonlinear equations exact vortex solutions
are found. Conditions for experimental observations of these vortices are
determined.Comment: 28 pages, 9 figures, Late
Radiation forces and confinement of neutral particles into the pulse envelope. New regime of collision ionization
The aim of this work is to find analytical expressions of the radiation force
and potential densities arising from a laser pulse propagating in a dielectric
media. In the femtosecond region the force becomes strong enough to confine
neutral particles into the pulse envelope and translate them with the group
velocity in gases. Additionally, if the trapped particles are with high
density, the probability of collision with the free atoms and molecules in air
become significant. The collision energies are in the range of 12 - 24 GeV and
high enough to ionize the neutral atoms. Thus, a new type of collision
ionization can be observed, when powerful femtosecond pulses propagate in
gaseous media.Comment: 10 pages,2 figures. arXiv admin note: text overlap with
arXiv:2004.1371
Design and implementation of a DMD based volumetric 3D display
A real image swept-volume volumetric display is developed. A piston type moving screen is used to obtain the desired volume. A commercially available DMD device is used to project 2D slices of a 3D frame. There is a varying magnification effect during the projection because of the optical design of the system; raw 3D video frames are processed by a software to generate the appropriate 2D slices by also correcting the magnification. Synchronization between the hardware and the software is achieved via a microcontroller. The overall system is capable of printing 12 3D frames per second where a 3D frame consists of 90 2D slices with a resolution varying from 512x512 to 450x450 (approx. 20M voxels per one 3D frame). Although some flickering effect is observed due to rather low 3D frame rate, results are visually satisfactory. ©2008 IEEE
Reconstruction of computer generated holograms by spatial light modulators
Computer generated holograms generated by using three different numerical techniques are reconstructed optically by spatial light modulators. Liquid crystal spatial light modulators (SLM) on transmission and on reflection modes with different resolutions were investigated. A good match between numerical simulation and optically reconstructed holograms on both SLMs was observed. The resolution of the optically reconstructed images was comparable to the resolution of the SLMs. © Springer-Verlag Berlin Heidelberg 2006
Construction of plant transformation vectors carrying beet necrotic yellow vein virus coat protein gene (ii)- plant transformation
Fragments containing the coat protein gene of beet necrotic yellow vein virus were cloned in two plant transformation vectors: pCAMBIA3301M with the bar gene as selectable marker, and pCAMBIA1304M, with resistance to hygromycin. Three constructs were made of each vector: CPL, containing coat protein gene with leader sequence; CPS with coat protein gene, and CPSas with coat protein gene in antisense orientation. Vectors pC3301MCPL, pC3301MCPS. and pC3301MCPSas were used in Agrobacterium—mediated transformation of Nicotiana tabacum (tobacco), Nicotiana excelsior and Nicotiana benthamiana. Regenerants that developed roots on selective media were tested for the presence of CP fragments and the bar gene, but most regenerants were nontransformed (50-83% escapes). After all rooted plants had been selfed, and T1 seed germinated on selective media, only plants descending from one N. excelsior regenerant transformed with pC3301MCPS were positive for presence of bar gene and CPS fragment. Tobacco and Nicotiana benthamiana were transformed with constructs pC1304MCPS and pC1304MCPSas. Transformation efficiency was much higher and approximately 50% of regenerants that rooted on media with 20 mg l−1 hygromycin were positive for the presence of CP fragments. All T1 plants were positive for presence of CP fragments
Production of {\pi}+ and K+ mesons in argon-nucleus interactions at 3.2 AGeV
First physics results of the BM@N experiment at the Nuclotron/NICA complex
are presented on {\pi}+ and K+ meson production in interactions of an argon
beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 AGeV. Transverse
momentum distributions, rapidity spectra and multiplicities of {\pi}+ and K+
mesons are measured. The results are compared with predictions of theoretical
models and with other measurements at lower energies.Comment: 29 pages, 20 figure
Probiotic lactobacilli inhibit early stages of Candida albicans biofilm development by reducing their growth, cell adhesion, and filamentation
We evaluated the inhibitory effects of the probiotic Lactobacillus species on different phases of Candida albicans biofilm development. Quantification of biofilm growth and ultrastructural analyses were performed on C. albicans biofilms treated with Lactobacillus rhamnosus, Lactobacillus casei, and Lactobacillus acidophilus planktonic cell suspensions as well as their supernatants. Planktonic lactobacilli induced a significant reduction (p\ua0\ua00.05), but significantly reduced the early stages of Candida biofilm formation (p\ua
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