has changed course and will have a vote tomorrow on another $60 billion for that war. and tonight, ukraine is making a desperate plea. president zelenskyy says that without more air defense systems, ukraine won t be able to hold off russian attacks. with me now is retired lieutenant colonel alexander vindman. he s the former european affairs director for the national security council and is a senior adviser. now to vote vats, he also has just returned from a trip to you crane kernel vindman, thanks for joining us. you ve been to ukraine quite a lot throughout this war. how was the situation on the ground today? different i think this was a bit of a wake-up call this visit you could sense it in the engagements with the armed forces. they re having a hard time contending with the russian onslaught the lack of artillery, ammunition being provided by the us and the west has really was one of the contributing factors to the fall of the city of dft in the
We theoretically devised a novel complex by decorating Li atoms on the α-C3N2 for hydrogen storage, employing first-principles calculations. The findings reveal that: Li can be securely adsorbed onto the α-C3N2; the Li@α-C3N2 exhibits commendable thermal stability and boasts an excellent electronic structure due to the sp2 hybridization, making it highly conducive to hydrogen adsorption; the Li@α-C3N2 can adsorb 12 H2, achieving a capacity of 5.7 wt%; the average adsorption energy (0.215 eV ∼ 0.228 eV) falls within reversible hydrogen-storage range; the corresponding desorption temperature ranges from 277 K to 293 K. Additionally, the storage capacity of the Li@α-C3N2 can be as high as 5.7 wt% at 300 K and 10 bar. The adsorption mechanism can be attributed to a combination of electrostatic interactions, orbital interactions and van der Waals interactions between the substrate and hydrogen molecules.
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Under the background of energy crisis, hydrogen owns the advantage of high combustion and shows considerable environment friendliness; however, to fully utilize this novel resource, the major hurdle lies in its delivery and storage. The development of the in-depth yet systematical methodology for two-dimensional (2D) storage media evaluation still remains to be challenging for computational scientists. In this study, we tried our proposed evaluation protocol on a 2D material, g-C3N5, and its hydrogen storage performance was characterized; and with addition of Li atoms, the changes of its electronical and structural properties were detected. First-principles simulations were conducted to verify its thermodynamics stability; and, its hydrogen adsorption capacity was investigated qualitatively. We found that the charges of the added Li atoms were transferred to the adjacent nitrogen atoms from g-C3N5, with the formation of chemical interactions. Thus, the isolated metallic sites tend to s