This paper presents an analysis of the motion of an neutral impurity species in a nanometer scale 4He cluster, extending a previous study of the dynamics of an ionic impurity. It is shown that for realistic neutral impurity–He potentials, such as those of SF6 and OCS, the impurity is kept well away of the the surface of the cluster by long range induction and dispersion interactions with He, bu...

This paper presents an analysis of the motion of a neutral impurity species in a nanometre scale He cluster, extending a previous study of the dynamics of an ionic impurity. It is shown that for realistic neutral impurity± He potentials, such as those of SF6 and OCS, the impurity is kept well away from the surface of the cluster by long range induction and dispersion interactions with He, but t...

Using an asymptotic solution of the M -impurity thermodynamics of a dilute s-d system, the impurity energy and impurity heat capacity ∆C(T ) are derived for dilute magnetic alloys with spin 1/2 and spin 3/2 impurities. The parameters which enter ∆C are adjusted to fit experimental data on impurity heat capacity of CuCr and (La1−xCex) Al2. Agreement is satisfactory for CuCr, at temperatures belo...

in this paper, the electronic eigenstates and energy spectra of single and two-interacting electrons confined in a concentric double quantum rings with a perpendicular magnetic field in the presence of         on-center donor and acceptor impurities are calculated using the exact diagonalization method. for a single electron case, the binding energy of on-center donor and acceptor impurities ar...

A sensitive and stable High Performance liquid chromatographic method has been developed for the identification of three process related impurities viz impurity-A, impurity-B and impurity-C in Dapoxetine hydrochloride. The method was optimized based on the peak shape and resolution of impurity-A, impurity-B and impurity-C. Phenomenex Luna C18 column (250mm×4.6 mm, 5um) was used for optimization...

Local magnetic properties around a nonmagnetic impurity are investigated in high-Tc cuprate superconductors. We consider a model two-dimensional dx2−y2-wave superconductor with strong antiferromagnetic (AF) spin fluctuations and calculate the spin susceptibility around the impurity. We show that the uniform susceptibility (χ(0)), which is usually suppressed in spin-singlet superconductivity, is...

I N T RO DU C T IO N A company that manufactures drug product or drug substance has a vested interest in determining the impurities associated with their compounds. The analysis of impurities can be a very labor-intensive task involving method development, impurity synthesis, isolation techniques, and various analytical approaches to determine the unambiguous identification of the impurity of i...

This study details the isolation, identification, and characterization of ambroxol's unknown impurity. One unknown impurity of ambroxol was formed in the formulated drug under stress conditions [40°C /75% relative humidity (RH) for 6 months] with the relative retention time (RRT) 0.68 in RP-HPLC. The impurity was enriched by exposing it to heat and it was isolated by using preparative HPLC. The...

Although in vitro transport/inhibition studies are commonly performed on impure drug candidates to screen for pharmacokinetic properties in early development, quantitative guidelines concerning acceptable impurity levels are lacking. The broad goal was to derive models for the effect of impurity on transport and inhibition studies and identify the maximum allowable impurity level that does not ...