Qikun Pan

Facile synthesis of a continuous thin Cu(bipy)2(SiF6) membrane with selectivity towards hydrogen

Cu(bipy)2(SiF6) is a highly porous metal–organic framework (MOF) and represents a prototypal “pillared sheet” platform offering opportunities to control the pore sizes. Its structural features, low cost and facile synthesis make it a great candidate to fabricate membranes for gas separation. The key to obtaining thin, continuous Cu(bipy)2(SiF6) membranes is to control the Cu(bipy)2(SiF6) crystal growth and enhance the binding between membrane and substrate. Here we explored a new route by direct synthesis and successfully obtained a continuous thin Cu(bipy)2(SiF6) membrane on a macroporous glass-frit disk with high robustness. It is speculated that the SiF62− used to construct the Cu(bipy)2(SiF6) membrane came from the fluorinated substrate. The Cu(bipy)2(SiF6) membrane shows the separation factors of H2–CO2, H2–CH4 and H2–N2 are 8.0, 7.5, and 6.8 respectively at 293 K and 1 bar with H2 permeance of 2.7 × 10−7 mol m−2 s−1 Pa−1 as well as high thermal stability. We expect to explore more membranes of Cu(bipy)2(SiF6) analogues with tuneable pore sizes using this route and to obtain membranes with higher gas separation performance.

Experimental study on non-chain electric-discharge pulsed DF laser

The working mechanism of the non-chain pulsed DF laser is analyzed in this paper, then the glow discharge with the method of UV-preionized discharge is displayed, and finally the experimental investigation on the output characteristics of non-chain pulsed DF laser is done. With SF6, which is non-toxic and non-corrosive, and D2 as the active medium, the dependence of the output characteristics of pulsed DF laser on the gas mixture ratio and the total pressure are investigated. In the experiment, the optimal gas mixture ratio of SF6-D2 and total pressure are 10:1 and 10.5kPa, respectively. At the same time, by making a measurement on the output spectrum of DF laser with a DF laser spectrum analyzer, 17 P-branch transition lines are achieved and the majority of output energy is concentrated on several lines near the 3.876μm line. The laser beam divergence angles in horizontal and vertical directions are 1mrad by using the laser spot ablation method. At the charging voltage of 39kV, under the best working condition(SF6: D2 = 10:1, Ptotal= 10.5kPa), the maximum single pulse output energy of 3.58J, pulse duration of 215ns, peak power of 16.65 MW, and electro-optical conversion efficiency of 2.08%, are obtained.