HS0507+0434 and HS 2240+1234 are two new common proper motion pairs of DA white dwarfs, discovered by the Hamburg Quasar Survey. Our model atmosphere analysis shows that HS 0507+0434A has an effective temperature of 20000K and is remarkably young (τcool <1Gyr) compared to the average cooling time of all known wide double degenerates (≈ 3Gyr). The cooler B component of HS 0507+0434 is particular...

Assessment of groundwater quality is important for drinking water, especially rural populations. The aim this study was to assess the human consumption by integrating water index with geographic information system (GIS) eventual interpretation Meknes area quality. Eight wells and two springs were investigated between February 2013 2014. In light analysis results, spatial distribution maps chose...

The iron phosphates [C4H12N2][Fe (H2O)6](HPO4)2 (1), 3 ‘{[NH4][Fe III 2(OH)(PO4)2(H2O)]?H2O} (2) and 3 ‘{[C4H12N2][Fe III 3(PO4)3(HPO4)(H2O)]?y0.25H2O}, (3) were synthesized by hydrothermal methods and their single-crystal X-ray structures were determined. While compound 1 is only an extended hydrogen bonded network of its three ionic building blocks, compounds 2 and 3 are three-dimensional ope...

The proton transfer reaction of H3O 1 and NH3 was studied using the crossed molecular beam technique at relative energies of 0.41, 0.81, and 1.27 eV. At all three energies, the center-of-mass flux distribution of the product ion NH4 1 exhibits sharply asymmetry, and the maximum is close to the velocity and direction of the precursor ammonia beam. The reaction transforms almost all of the 1.69 e...

MnO2 was synthesised as a catalyst support material using a hydrothermal method. This involved reacting MnSO4⋅H2O and (NH4)2S2O8 at 120 °C for a range of crystallisation times, which affords control over the morphology and phase composition of the MnO2 formed. Gold was deposited on these supports using sol-immobilisation, impregnation and deposition precipitation methods, and the resultant mate...

A hybrid quantum mechanical molecular mechanical ~QMMM! approach is used to study H3O , H2O, NH4 1 , NH3 , Cl , HCl, F, HF, CH3COO , CH3COOH, Ag 1 and glycine in both zwitterionic and nonzwitterionic forms in water. The free energies of hydration of these species are presented and are shown to compare favorably with experimental values. The difference in water– glycine interaction energy betwee...

In previous researches, there are few studies on the mechanisms involved in liquid-liquid doping techniques for preparing oxide particle doped tungsten powders. this research, based different polytungstate species, three liquid–liquid synthesizing precursor powders were proposed and compared. The extremely homogeneous hexagonal (NH4)0.33WO3·H2O microspheres flaky (NH4)6H2W12O40·5H2O synthesized...

The dielectric and pyroelectric properties of ammonium hydrogen-DL-malate monohydrate NH® (OOCCHOHCH2COOH) • H 2 0 were studied as a function of temperature and crystallographic direction. The components of the dielectric tensor at room temperature are within the limits 5.9 S e ^ 8.6. The pyroelectric coefficient \p\ increases from « 18 (iC m~ K at T = 100 K to 32 (iC m" K at room temperature. ...