We consider the application of a perfectly matched layer (PML) technique applied in Cartesian geometry to approximate solutions of the acoustic scattering problem in the frequency domain. The PML is viewed as a complex coordinate shift (“stretching”) and leads to a variable complex coefficient equation for the acoustic wave posed on an infinite domain, the complement of the bounded scatterer. T...

Zinc oxide thin films have been obtained on bare and GaN buffer layer decorated Si (111) substrates by pulsed laser deposition (PLD), respectively. GaN buffer layer was achieved by a two-step method. The structure, surface morphology, composition, and optical properties of these thin films were investigated by X-ray diffraction, field emission scanning electron microscopy, infrared absorption s...

We present a review on the accuracy of asymptotic models for the scattering problem of electromagnetic waves in domains with thin layer. These models appear as first order approximations of the electromagnetic field. They are obtained thanks to a multiscale expansion of the exact solution with respect to the thickness of the thin layer, that makes possible to replace the thin layer by approxima...

There has been a tendency to discount thin-layer chromatography (TLC) in recent years because of the availability of high-performance liquid chromatography (HPLC) methods that appeared to offer greater versatility and ease of quantification, amongst other reasons. However, TLC has made a comeback, largely because of the high reproducibility and lower costs of commercial pre-coated plates. It is...

Thin layer chromatography (TLC) is a useful technique for the separation and identification of compounds in mixtures. TLC is used routinely to follow the progress of reactions by monitoring the consumption of starting materials and the appearance of products. Commercial applications of TLC include the analysis of urine for evidence of "doping", the analysis of drugs to establish purity or ident...

Ceramides with mono-, di-, and trihydroxy long-chain bases, and normal (saturated and unsaturated), branched-chain, and 2-hydroxy fatty acids have been analyzed by thin-layer chromatography. In most cases the compounds were also run as acetates. Borate, arsenite, and silver ions were used as complexing agents, and the effects of number, position, and stereochemistry of hydroxy groups, and of un...

The various OPLC andRPC techniques are compared in Table 1. Study of the data shows that OPLC is an excellent technique for analytical separations and that RPC is more ideally suited as a preparative method for isolation of compounds from biological matrices. The advantage of combining online and ofSine separations and two-dimensional development can also be exploited in OPLC. The advantage of ...

During the hypersonics activities of the 1960s, thin shock-layer theory was developed as a rst-order correction to Newtonian theory, in the hope of gaining insight into eÆcient lift at very high speeds. The wings are limited to conical geometry, but can have arbitrary transverse camber. Good predictions were made of the forces generated by delta and caret wings, but no optimization studies were...

The intermetallic compounds formed during the diffusion soldering of a Bi2Te2.55Se0.45 thermoelectric material with a Cu electrode are investigated. For this bonding process, Bi2Te2.55Se0.45 was pre-coated with a 1 μm Sn thin film on the thermoelectric element and pre-heated at 250 ̋C for 3 min before being electroplated with a Ni barrier layer and a Ag reaction layer. The pre-treated thermoele...