Zeolites belong to a most prominent class of nanoporous materials which have been considered as potential sorbents for hydrogen storage. The adsorption of hydrogen molecules on MFI, MOR and LTA zeolites, which encompass a range of different pore structure and chemical composition, has been simulated employing Grand Canonical Monte Carlo (GCMC) method. We compare their capacities of hydrogen storage at different temperatures and pressures. The results show that the adsorbed amounts is in order of LTA>MOR>MFI at the same condition. The effects of pore structure of zeolites, temperature and pressure on the hydrogen adsorption has been examined. The results clearly show that: (1) the temperature effect on the adsorption decreases with decreasing in the number of hydrogen molecules adsorbed. (2) A large volume of micropores and a suitable diameter near to the kinetic diameter of a hydrogen molecule are important for improving the hydrogen-storage capacity of zeolites. Based on this, we can conclude that the LTA zeolite with a large pore volume and a suitable channel diameter exhibits a most efficient hydrogen storage capacity than MOR and MFI zeolites.
Using first-principles density-functional theory investigate (5, 5) capped single-walled carbon nanotubes adsorbed at one end by hydrogen molecule with and without an applied electric field. It is found that the structure of carbon nanotubes with hydrogen molecules is stable under field-emission conditions. The induced dipole moments is the direction of the applied electric field,and the LUMO-HOMO energy gaps decrease. These results elucidate that the field-emission properties of carbon nanotubes can be enhanced by the adsorption of hydrogen molecules, and are consistent with the experimental results.
Carbon nanotubes(CNTs) films were fabricated by microwave plasma chemical vapor deposition (MPCVD) on stainless steel substrates. In order to study the reason that its emission current weakens, the CNTs films were treated by hydrogen plasma. The research discovered that the hydrogen plasma treatment to the carbon nanotubes films reduced the surface work function of the film and its filed emission current, this mainly due to the etching of hydrogen plasma to sp2 carbon on the surface, it leads emission area to decrease.
Chongqing Fuling Fifth landslide is a large landslide along the layers of rock. It has the following characteristics such as high sliding speed, serious damage and other characteristics. Based on landslide characteristics and governance requirements, we set three governance programs. Considering the function and cost, we use DARE method for value engineering analysis. The analysts believe that an optimum solution can be given priority, and the program has also been recommended by the review panel members unanimously approved. Upon completion of the large program selection, we further analyzed the principle of value for the selected program to optimize the sub-projects, which achieved good economic and social benefits of cost-effectiveness.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.