The hyperfine properties of a hydrogenated Fe/V superlattice

: We study the effect of hydrogen on the electronic, magnetic and hyperfine structures of an iron-vanadium superlattice consisting of three Fe monolayers and nine V monolayers. The contact charge density ({\rho}), the contact hyperfine field (Bhf) and the electronic field gradient (EFG) at the Fe sites for different H locations and H fillings are calculated using the first principle full-potential linear-augmented-plane-wave (FP-LAPW) method . It is found that sizeable changes in the hyperfine properties are obtained only when H is in the interface region.Comment: 6 pages, 2 figures, 3 tables, ICAME 2011 conference (Kobe, Japan

Cognitive function during early abstinence from opioid dependence: a comparison to age, gender, and verbal intelligence matched controls

BACKGROUND: Individuals with opioid dependence have cognitive deficits during abuse period in attention, working memory, episodic memory, and executive function. After protracted abstinence consistent cognitive deficit has been found only in executive function. However, few studies have explored cognitive function during first weeks of abstinence. The purpose of this study was to study cognitive function of individuals with opioid dependence during early abstinence. It was hypothesized that cognitive deficits are pronounced immediately after peak withdrawal symptoms have passed and then partially recover. METHODS: Fifteen patients with opioid dependence and fifteen controls matched for, age, gender, and verbal intelligence were tested with a cognitive test battery When patients performed worse than controls correlations between cognitive performance and days of withdrawal, duration of opioid abuse, duration of any substance abuse, or opioid withdrawal symptom inventory score (Short Opiate Withdrawal Scale) were analyzed. RESULTS: Early abstinent opioid dependent patients performed statistically significantly worse than controls in tests measuring complex working memory, executive function, and fluid intelligence. Their complex working memory and fluid intelligence performances correlated statistically significantly with days of withdrawal. CONCLUSION: The results indicate a rather general neurocognitive deficit in higher order cognition. It is suggested that cognitive deficit during early abstinence from opioid dependence is related to withdrawal induced neural dysregulation in the prefrontal cortex and is partly transient

Mössbauer Spectroscopy On Selectred Magnetic Compounds

The applications of magnetic materials are related to their magnetic and crystal structure as well as electronic properties. In this thesis, mainly experimental methods have been focussed on novel materials and bulk materials. A selection of materials were studied by several techniques like Mössbauer spectroscopy, X-ray and neutron diffraction and magnetisation measurements. New technology allow us to prepare artificial materials with unic magnetic properties. Magnetic multilayers are very interesting not only from phenomenological point of view but also as good applications materials. In this work will be shown some results from Fe/V and Fe/Co multilayer system The (Fe1-xMnx)3P system has been studied at both ends of the composition range. At the Fe-rich end, compounds exhibiting ferromagnetic ordering are formed, while at the Mn-rich end, an antiferromagnetic coupling was discovered. The experimental results are supported by theoretical calculations. Rare-earth compounds with focus on Fe0.65Er0.2B0.15 were studied by means of traditional Mössbauer spectroscopy, Monochromatic Circular Polarized Mössbauer Spectroscopy, X-ray diffraction and magnetic mesurements. This compound shows interesting behaviour of Fe magnetic moment at low and room temperature. The first magnetic studies on rhombohedral Li3Fe2(PO4)3 at low temperature has also been made and an antiferromagnetic structure was revealed

Studies of the Magnetite Nanoparticles by Means of Mössbauer Spectroscopy

The magnetite nanoparticles were prepared by modified Massart's method in water and in alcohol. The influence of the condition of preparation on the properties of magnetite nanoparticles were investigated by Mössbauer spectroscopy. The size of the particles were determined by transmission electron microscopy. It was shown that the particles size in the alcoholic reaction is smaller than in aqueous reaction. Moreover, the increase in the reaction time improves the stoichiometry of magnetite nanoparticles