Meiguang Zhang

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Additional electrons can drastically change the bonding trend of light elements. For example, N atoms in alkali metal azides form the linear N3(-) anions instead of N2 molecules with the introduction of additional electrons. The effect of the additional electrons on the polymerization of N under pressure is important and thus far unclear. Using first(More)
The search for novel superhard materials with special structures and improved thermal stability and hardness remains considerably experimental and theoretical challenges. Recent reports proposed that higher carbon content in ternary B2CxO compounds, which are isoelectronic with diamond, would lead to increased strength and hardness. This notion was derived(More)
Motivated by a recently predicted structure of diamond-like BC 2 with a high claimed hardness of 56 GPa (J., we focus on whether this tetragonal BC 2 (t-BC 2) is superhard or not in spite of such an ultrahigh theoretical hardness. The mechanical properties of t-BC 2 were thus further extended by using the first principles in the framework of density(More)
Recently, a new high-pressure semiconductor phase of Ca 2 C (space group Pnma) was successfully synthesized, it has a low-pressure metallic phase (space group C2/m). In this paper, a systematic investigation of the pressure-induced phase transition of Ca 2 C is studied on the basis of first-principles calculations. The calculated enthalpy reveals that the(More)
Hair cells in posthatch chickens regenerate spontaneously through mitosis or the transdifferentiation of supporting cells in response to antibiotic injury. However, how embryonic chicken cochleae respond to antibiotic treatment remains unknown. This study is the first to indicate that unlike hair cells in posthatch chickens, the auditory epithelium was free(More)
Motivated by recent successful synthesis of transition metal dinitride TiN2, the electronic structure and mechanical properties of the discovered TiN2 and other two family members (ZrN2 and HfN2) have been thus fully investigated by using first-principles calculations to explore the possibilities and provide guidance for future experimental efforts. The(More)
First-principles calculations were employed to study the mechanical properties for the recently proposed tetragonal B4CO4 (t-B4CO4). The calculated structural parameters and elastic constants of t-B4CO4 are in excellent agreement with the previous results, indicating the reliability of the present calculations. The directional dependences of the Young’s(More)
Using the particle swarm optimization technique, we proposed a cubic superhard phase of C 3 N (cC 3 N) with an estimated Vicker's hardness of 65 GPa, which is more energetically favorable than the recently proposed o-C 3 N. The cC 3 N is the most stable phase in a pressure range of 6.5–15.4 GPa. Above 15.4 GPa, the most energetic favorable high pressure(More)
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