The control of impurities in Formulated products and Active Pharmaceutical ingredient’s were regulated by various regulatory authorities like US-FDA,ICH,MHRA,TGA etc.As per International Conference on Harmonization guidelines, the Impurity may be defined as any component of new drug product that is not the drug substance or an excipient in drug product. Nowadays apart from purity profile there ...

In wide bandgap GaN a large number of interesting and important scientific questions remain to be answered. For example, the large free electron concentration reaching 1019 to 1020 cm-3 in nominally undoped material are ascribed to intrinsic defects because no chemical impurity has been found at such high concentrations. According to theoretical models a nitrogen vacancy acts as a donor but its...

Electronic structures of zigzag edged graphene nanoribbons (ZGNRs) doped with boron (B) or nitrogen (N) atoms are investigated by spin polarized first-principles calculations. We find that ZGNRs can be tuned to be either semiconducting, half-metallic, or metallic by controlling the distance of the impurity atoms to the edges. A new scheme is identified to achieve full half-metallicity in ZGNRs ...

High-quality InN epitaxial films have been grown by nitrogen-plasma-assisted molecular-beam epitaxy on Si~111! substrates using a double-buffer technique. Growth of a ~0001!-oriented single crystalline wurtzite–InN layer was confirmed by reflection high-energy electron diffraction, x-ray diffraction, and Raman scattering. At room temperature, these films exhibited strong near-infrared ~0.6–0.9 ...

A 100 MeV electron laser wakefield injector based on a sub-millimeter gas cell is presented. The gas cell, used mainly to overcome the density inhomogeneity associated with gas jets, is capable of yielding a homogeneous plasma source with densities less than 2 x 10 cm. Sharp step plasma density boundaries were obtained by using the laser to drill the gas cell pinholes as small as 100 μm in diam...

The luminescence of amorphous silicon layers either implanted with Er or co-implanted with Er and O has been studied by photoluminescence (PL) and cathodoluminescence (CL) in the scanning electron microscope. Annealing in nitrogen causes the formation of oxide species and Er-Si complexes or precipitates as well as spectral changes in the visible and infrared ranges. The main CL emission takes p...

Boron nitride ~BN! thin films ~containing mixed cBN/hBN phase! have been deposited on Si~100! substrates using neutralized nitrogen beam and electron beam evaporation of boron. All as-deposited BN films were p type with a room-temperature carrier concentration in the range of 5310 to 1310 cm. The Mg-doped BN films showed carrier concentrations in the range of 1.2 310 cm to 5.2310 cm when the Mg...

Exploiting a controllable technique for red and blue shifting of quantum well’s bandgap energy, we have fabricated LED sources accessing a wide frequency spectrum along with all-optical intensity modulator devices. . We demonstrate bandgap tuning of InGaAsP multiple quantum well structures by utilizing an impurity free vacancy diffusion technique. Substantial modification of the bandgap energy ...

We study the structure and stability of nonlinear impurity modes in the discrete nonlinear Schrödinger equation with a single on-site nonlinear impurity emphasizing the effects of interplay between discreteness, nonlinearity, and disorder. We show how the interaction of a nonlinear localized mode (a discrete soliton or discrete breather) with a repulsive impurity generates a family of stationar...

The binding energy of ground state for hydrogenic impurity in multiple quantum dots is calculated in the framework of effective-mass approximation and using a variational method. It is shown that the binding energy is a function of the size of dots, impurity position and external fields strength. The binding energy has a maximum value when the impurity is located on the center of dots and decre...