We report a widely tunable narrowband terahertz (THz) source via difference frequency generation (DFG). A narrowband THz source uses the output of dual seeded periodically poled lithium niobate (PPLN) optical parametric generators (OPG) combined in the nonlinear crystal 4-dimthylamino-N-methyl-4-stilbazolium-tosylate (DAST). We demonstrate a seamlessly tunable THZ output that tunes from 1.5 THz...

BACKGROUND Derivatives of D-glucosamine and D-galactosamine represent an important family of the cell surface glycan components and their fluorinated analogs found use as metabolic inhibitors of complex glycan biosynthesis, or as probes for the study of protein-carbohydrate interactions. This work is focused on the synthesis of acetylated 3-deoxy-3-fluoro, 4-deoxy-4-fluoro and 3,4-dideoxy-3,4-d...

Organic crystals of trans-4-[4-(dimethylamino)-N-methylstilbazolium] p-tosylate (DAST) with enhanced nonlinear optical properties were successfully prepared at the nanometre scale due to the influence of a carbosiloxane dendrimer (CSiO-D).

The first example of DAST-promoted Beckmann rearrangement/intramolecular cyclization of acyclic ketoximes is described. This unique protocol represents a direct and effective pathway to 2-oxazolines, benzimidazoles and benzoxazoles in moderate to good yields.

It has been shown that the spectrum of intense few-cycle terahertz radiation generated in a DAST organic crystal can be controlled by chirping 1.24-μm pump femtosecond laser chromium forsterite system. found an increase linear chirp generating results narrowing and its redshift. The simulation generation within model three-wave mixing this effect is due to change phase matching width degenerate...

We start with a combinatorial definition of I-sign types which are a generalization of the sign types indexed by the root system of type Al (I ⊂ N finite). Then we study the set DI p of I-sign types associated to the partial orders on I. We establish a 1-1 correspondence between D [n] p and a certain set of convex simplexes in a euclidean space by which we get a geometric distinction of the sig...

High-energy terahertz pulses are produced by optical rectification (OR) in organic crystals 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) and 4-N, N-dimethylamino-4'-N'-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) by a Ti:sapphire amplifier system with 0.8 μm central wavelength. The simple scheme provides broadband spectra between 1 and 5 THz, when pumped by a collimate...

A new class of full diversity space-time codes is proposed that leads to a significantly smaller Peak-to-Mean Envelope Power Ratio (PMEPR) compared to the recently invented Diagonal Algebraic SpaceTime (DAST) and Threaded Algebraic Space-Time (TAST) codes. Moreover, the proposed “Low PMEPR Space-Time” (LPST) codes exhibit identical performance and decoding complexity compared to the TAST codes....

Computing the similarity between two protein structures is a crucial task in molecular biology, and has been extensively investigated. Many protein structure comparison methods can be modeled as maximum clique problems in specific k-partite graphs, referred here as alignment graphs. In this paper, we propose a new protein structure comparison method based on internal distances (DAST), which mai...