نتایج جستجو برای: niobium compounds
تعداد نتایج: 229674 فیلتر نتایج به سال:
In the present research, to form niobium carbide coating on the surface of AISI L2 steel Thermo-Reactive Deposition method (TRD) in a molten bath was used. Niobium carbide coating treatment was carried out at 1173 K, 1273 K, and 1373 K for 2, 4, and 8 hours. The molten bath contained 20wt.% borax (Na2B4O7), 5 wt.% boric acid (B2O3), and 75 wt.% ferro-niobium. The presence and properties of...
The promoting effect of niobium in a Li/MgO catalyst for the oxidative coupling of methane (OCM) and for the oxidattve dehydrogenation of ethane (ODHE) has been studied in some detail. it has been found that a Li/Nb/MgO catalyst with 16 wt % niobium showed the highest activity for the C, production in the OCM reaction; the activity at 600 “C was ten times that of the Li/MgO catalyst at the same...
Weyl semimetals are expected to open up new horizons in physics and materials science because they provide the first realization of Weyl fermions and exhibit protected Fermi arc surface states. However, they had been found to be extremely rare in nature. Recently, a family of compounds, consisting of tantalum arsenide, tantalum phosphide (TaP), niobium arsenide, and niobium phosphide, was predi...
The title compounds were prepared by direct reaction of the corresponding elements at high temperature. Their structures were determined by single-crystal X-ray diffraction (Cs24Nb2In12As18, triclinic, P1, Z=1, a=9.519(4), b=9.540(5), and c=25.16(1) A, alpha=86.87(4), beta=87.20(4), and gamma=63.81(4) degrees; Cs13Nb2In6As10, triclinic, P1, Z=1, a=9.5564(5), b=9.6288(5), and c=13.9071(7) A, alp...
1- in a search directed to the reaction of compound)23(the cycloaddition reaction of 1,3- diphenylisobenzofurane)14(with p-benzoquinone)19(,followed by addition of cyclopentadiene was carried out.the specific spacial stracture of its ir,nmr,mass spectra. 2- in another attempt the kinetic stability and behavior of compounds)20(and)23(was studied.the main subject of this study was the highly reve...
In order to test the microwave properties of superconductors, we are developing a disk resonator, to be operated in the TM010 mode at 3.36 GHz. The goal is a measurement of microwave surface resistance at both low and high power, initially for niobium thin films, but eventually for other thin film superconductors. The currents in a disk resonator flow in and out radially. Edge currents are zero...
After a very active period of Niobium Titanium superconductor strand development in the mid 1980s, progress slowed as the SSC scaled up for production and emphasis moved towards guaranteeing, rather than enhancing performance. However, this period also produced several advances in the understanding of flux pinning in Niobium Titanium alloys and in the fabrication of composites containing artifi...
We calculate the electronic structure of 3d impurities in niobium and molybdenum. Our calculations rely on the local density approximation of density functional theory. Assuming a muffin-tin description of the atomic potentials, the impurity potential and the ones of the nearest neighbours are calculated self-consistently while the embedding of this perturbed cluster into the host is described ...
Recently the UHV arc technology was proposed as a possible alternative for depositing thin superconducting films of pure niobium on the inside surface of RF cavities for particle accelerators. The paper describes status of research on deposition of superconducting films for RF accelerating cavities. New UHV arc based devices with planar and cylindrical niobium cathodes are presented. The main r...
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