Spin-polarised local density functional cluster calculations are carried out on iso-(S=1/2) lies at the T d site. Ni ? s (S=3/2) is shown to be stable and remains on-site in agreement with experimental results. Donor-acceptor complexes of Ni, namely Ni + i-B ? s , Ni ? s-N + s and Ni + s-B ? s are stable trigonal defects which have a number of gap levels. Optical transitions are expected betwee...

Spin-polarized local density functional cluster calculations are carried out on substitutional Ni and Ni-H 2 complexes. We nd that Ni ? undergoes a Jahn-Teller distortion along h100i with Ni moving slightly along the cube axis. The distorted state gives b 1 ; b 2 and a 1 levels in ascending order of energies within the gap in agreement with experiment. Several candidate NiH 2 defects are invest...

in this research, tribological characteristics of ni-p electroless coating and double-layered ni-p/ni-b electroless coating were studied. for this purpose, ni-p electroless coating with 25 μm thickness was initially applied to the surface of steel ck45 samples; then, a double-layered ni-p/ni-b electroless coating, including inner layer of ni-p with 15 μm thickness and outer layer of ni-b with 1...

Hyperaccumulated elements such as Ni may defend plants against some natural enemies whereas other enemies may circumvent this defense. The Ni hyperaccumulator Berkheya coddii Roessler (Asteraceae) is a host plant species for Chrysolina clathrata (Clark), which suffers no apparent harm by consuming its leaf tissue. Beetle specimens collected from B. coddii had a whole body Ni concentration of 26...

The Ni–Al–Ti system contains three intermetallic phases, c=, b, and b= which have complementary properties. The objective of the present investigation was to coextrude these three phases to form a metal–metal composite (MeMeC) and investigate the mechanical properties and failure mechanisms of such a material. High strengths, comparable with that of the strongest constituent phase, have been re...

Exposure of the hyperaccumulator Alyssum lesbiacum to nickel (Ni) is known to result in a dose-dependent increase in xylem sap concentrations of Ni and the chelator free histidine (His). Addition of equimolar concentrations of exogenous L-His to an Ni-amended hydroponic rooting medium enhances Ni flux into the xylem in the nonaccumulator Alyssum montanum, and, as reported here, in Brassica junc...

the stability constants of species present in the systems ni(ii)-pyridoxamine(pym)(a) and ni(ii)-pyridoxamine(pym)(a)-imidazole containing ligands(b) [b = imidazole(him),  benzimidazole(bim), histamine(hist) and l-histidine(his)] have been determined ph-metrically using the miniquad computer program. the existence of the species niah, nia and nia2 was proven for the ni(ii)-pym(a) system, wherea...

We wish to reduce the number of parameters in the model and make it so that the model is more easily comparable to our previous work [1]. To do this we first look at the nonspatial single morph model which is given by: Ni(t+ 1) = (1 + b)Ni(t) exp(−mi −mi (1 + b)Nt) For the purpose of this model we want the carrying capacity K to be fixed by the equilibrium population density. We therefore calcu...