نتایج جستجو برای: alkali metal alloy
تعداد نتایج: 257426 فیلتر نتایج به سال:
Background: Orthodontics is a part of dentistry that includes preventive methods and correction of dental irregularities that need to be repositioned by functional and mechanical tools to provide an ideal occlusion and a beautiful face for patients. There are currently four metal arch wires used in orthodontic treatment: stainless steel alloy, cobalt-chromium alloy, nickel-titanium alloy, and b...
The mechanisms of the carboxylations of lithium, potassium, rubidium, and cesium phenoxides are investigated by means of the DFT method with the LANL2DZ basis set. It is shown that the reactions of all alkali metal phenoxides with carbon dioxide occur via very similar reaction mechanisms. The reactions can proceed in the ortho and para positions. The exception is lithium phenoxide which yields ...
BACKGROUND The purpose of this study was to evaluate and compare the micro tensile bond strength of two metal bonding resin cements to sandblasted cobalt chromium alloy. MATERIALS & METHODS Eight, Cobalt chromium alloy blocks of dimensions 10x5x5 mm were cast, finished and polished. One of the faces of each alloy block measuring 5x5mm was sandblasted with 50 μm grit alumina particles. The all...
A unique approach for obtaining bright and efficient saturated green phosphors for alternating-current thin-film electroluminescent ~ACTFEL! device applications is presented. The approach involves color-shifting blue SrS:Cu,F ACTFEL phosphors into the green region of the spectrum via the incorporation of alkali metal ions into the SrS lattice. Alkali metals are incorporated into SrS:Cu,F phosph...
We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M(1)); and 1 alkali, alkaline earth or 3d/4d transition metal atom (M(2)) plus two to five (BH(4))(-) groups, i.e., M(1)M(2)(BH(4))(2-5), using a number ...
Comparison of free energies between different phases and compositions underlies the prediction alloy phase diagrams. To allow direct comparison, consistent reference points for or enthalpies are required, entropy must be placed on an absolute scale, yielding energies. Here we derive liquids from ab initio molecular dynamics by combining directly simulated with derived densities pair correlation...
The purpose of this study was to evaluate the effects of the rate of argon gas flow on joint strength in the laser-welding of cast metal plates and to measure the porosity. Two cast plates (Ti and Co-Cr alloy) of the same metal were abutted and welded together. The rates of argon gas flow were 0, 5 and 10 L/min for the Co-Cr alloy, and 5 and 10 L/min for the Ti. There was a significant differen...
Nine 35% Ag-30% Pd-20% Au-15% Cu alloys containing 2, 4 and 6 mass% of Sn, Ga or In as an additive metal were experimentally prepared to investigate the effects of different additives and their content on the physical and mechanical properties as well as the bond with a ultra-low fusing ceramic. Both the different additives and their content or either of these two factors significantly influenc...
Quantum Monte Carlo methods are used to investigate the binding of a positron to the alkali-metal hydrides, XH (X = Na and K). We obtain positron affinities for the NaH and KH molecules of 1.422(10) eV and 2.051(39) eV, respectively. These are considerably larger than the previous results of 1.035 eV and 1.273 eV obtained from multireference single- and double-excitation configuration interacti...
The Fermi-contact interaction that characterizes collisional spin exchange of a noble gas with an alkali-metal vapor also gives rise to NMR and EPR frequency shifts of the noble-gas nucleus and the alkali-metal atom, respectively. We have measured the enhancement factor κ0 that characterizes these shifts for Rb-129Xe to be 493±31, making use of the previously measured value of κ0 for Rb-3He. Th...
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