نتایج جستجو برای: bar metal
تعداد نتایج: 226489 فیلتر نتایج به سال:
A microporous metal-organic framework, PCN-14, based on an anthracene derivative, 5,5'-(9,10-anthracenediyl)di-isophthalate (H4adip), was synthesized under solvothermal reaction conditions. X-ray single crystal analysis revealed that PCN-14 consists of nanoscopic cages suitable for gas storage. N2-adsorption studies of PCN-14 at 77 K reveal a Langmuir surface area of 2176 m2/g and a pore volume...
Several techniques exist for the repair of complex pectus excavatum. The placement of retrosternal metal bars improves the results by reducing the recurrence rate, but entails several possible risks, complications and disadvantages. A new method, specifically conceived for the repair of severe, asymmetric forms in adult patients, is reported. The corrected bone is fixed in the proper position b...
An all-metal lateral spin-valve structure has been fabricated with a medial Copper nano-ring to split the diffusive spin-current path. We have demonstrated significant modulation of the non-local signal by the application of a magnetic field gradient across the nano-ring, which is up to 30% more efficient than the conventional Hanle configuration at room temperature. This was achieved by passin...
Pressure-composition isotherm measurements show that the ternary lanthanum palladium silicide phase La3Pd5Si absorbs reversibly up to 5 hydrogen atoms per formula unit at 550 K and 14 bar hydrogen pressure. In-situ synchrotron and neutron powder diffraction reveals three phases, an alpha-phase having the limiting composition La3Pd5SiD approximately 1.6 at low deuterium pressure (at up to 9.5 ba...
We investigate the ability of counting rules drafted from engineering to predict the flexibility or rigidity of bar-and-joint or body-and-joint assemblies representing metal organic frameworks. We show that while scalar counting rules are not reliable, group-theoretical approaches are able to disentangle mechanisms from states of self-stress and to predict the existence of flexible mechanisms. ...
The MaxPHOX-Ir catalyst system provided the highest selectivity ever reported for the reduction of cyclic enamides derived from α- and β-tetralones. This result indicates that iridium catalysts are also proficient in reducing alkenes bearing metal-coordinating groups. In the present system, selectivity was pressure-dependent: In most cases, a decrease in the H2 pressure to 3 bar resulted in an ...
Saturation H2 uptake in a series of microporous metal-organic frameworks (MOFs) has been measured at 77 K. Saturation pressures vary between 25 and 80 bar across the series, with MOF-177 showing the highest uptake on a gravimetric basis (7.5 wt %) and IRMOF-20 showing the highest uptake on a volumetric basis at 34 g/L. These results demonstrate that maximum H2 storage capacity in MOFs correlate...
A zeolite-like microporous tetrazole-based metal-organic framework (MOF) with 24 nuclear zinc cages was synthesized and characterized. It exhibits high CO(2) adsorption capacity up to 35.6 wt % (8.09 mmol/g) and excellent CO(2)/CH(4) selectivity at 273 K/1 bar, being among the highest values known to date. Theoretical calculations based on simulated annealing techniques and periodic DFT reveale...
Nevertheless, in order to respond to the economic and environmental criteria, hydrogen production and storage have to be improved. This work focuses on gaseous storage under high pressure (700 bar) using a type III vessel (figure 1) that is to say composed of a metal liner – which prevents gas diffusion – and of a composite laminate wrapped by filament winding – which is used as a mechanical st...
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