Thermo-optic coefficient of chemical vapor deposited graphene multilayers

Observation of strong inelastic light-matter interaction and large thermal conductivity of novel two-dimensional graphene has invigorated the present research. Herein, the thermo-optic coefficient of graphene multilayers is obtained from their nonlinear refraction coefficients calculated from Z-scan experiment in closed aperture geometry. The refractive optical nonlinearity was obtained employing a continuous wave He-Ne laser and occurs due to thermal lensing effect. The graphene multilayers behave as the diverging (concave) lens giving rise to self-defocusing effect leading to negative sign of refractive nonlinearity. Accordingly, a large negative thermo-optic coefficient (-2.43×10-3 K-1) inferred for the graphene multilayers suggests its utility for thermo-optic device applications. Keywords: Graphene, Optical Nonlinearity, Thermal lens, Self-defocusing, Thermo-optic coefficient

Pulsed Laser Deposited Nickel Doped Zinc Oxide Thin Films: Structural and Optical Investigations

Structural and optical studies has been done on Nickel doped Zinc Oxide (NixZn1 – xO, x 0.03, 0.05 and 0.07 by weight) thin films prepared by pulsed laser deposition technique. The films are characterized by X-ray diffraction, Uv-vis spectroscopy, X-ray photoelectron spectroscopy. We observed a slight red shift in the optical band gap in the NiZnO subsequent to Ni doping. This shift can be assigned due to the sp-d exchange interaction of Ni- d states with s and p-states of ZnO. Also X-ray photoelectron spectroscopy studies show that Ni has well substituted in + 2 oxidation state by replacing Zn2+. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3101

Genetics of Alcoholism

Purpose of Review We review the search for genetic variants that affect the risk for alcohol dependence and alcohol consumption. Recent Findings Variations in genes affecting alcohol metabolism (ADH1B, ALDH2) are protective against both alcohol dependence and excessive consumption, but different variants are found in different populations. There are different patterns of risk variants for alcohol dependence vs. consumption. Variants for alcohol dependence, but not consumption, are associated with risk for other psychiatric illnesses. Summary ADH1B and ALDH2 strongly affect both consumption and dependence. Variations in many other genes affect both consumption and dependence—or one or the other of these traits—but individual effect sizes are small. Evidence for other specific genes that affect dependence is not yet strong. Most current knowledge derives from studies of European-ancestry populations, and large studies of carefully phenotyped subjects from different populations are needed to understand the genetic contributions to alcohol consumption and alcohol use disorders

Structural and Optical Studies of Magnesium Doped Zinc Oxide Thin Films

The paper describes the structural and optical properties of Magnesium doped Zinc Oxide (Mg 3.5 %, 6 %, 9 %, 12 % by weight) thin films prepared by pulsed laser deposition technique. The samples are characterized by X-ray diffraction technique, Ultra-violet visible absorption spectroscopy, X-ray photoelectron spectroscopy. X-ray diffraction results reveal the polycrystalline nature of samples with no impurity or secondary phase formation. Ultra-violet visible absorption spectroscopy studies show the blue shift in the optical band gap subsequent to Mg doping. X-ray photoelectron spectroscopy results reveal the replacement of Zn2+ cation by Mg2+ ion. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3101