Anisotropic structure deformation of β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine under high pressure: vibration spectra calculation and resolution based on AIMD simulation.

The phase transition of the β-HMX crystal has been widely studied under high pressure, but the microscopic transition mechanism is not sufficiently understood. In this article, we perform a series of molecular dynamics simulations focusing on structure deformation and the corresponding vibration spectra resolution of β-HMX at 0-40 GPa. Several typical pressure-induced phase transition processes are confirmed by analyzing the chemical bond, dihedral angle, charge transfer, and IR and Raman spectra.

The Structure Properties of Carbon Materials Formed in 2,4,6-Triamino-1,3,5-Trinitrobenzene Detonation: A Theoretical Insight for Nucleation of Diamond-like Carbon.

The structure and properties of nano-carbon materials formed in explosives detonation are always a challenge, not only for the designing and manufacturing of these materials but also for clearly understanding the detonation performance of explosives. Herein, we study the dynamic evolution process of condensed-phase carbon involved in 2,4,6-Triamino-1,3,5-trinitrobenzene (TATB) detonation using the quantum-based molecular dynamics method. Various carbon structures such as, graphene-like, diamond-like, and "diaphite", are obtained under different pressures.

Enhanced Effect of an External Electric Field on NHBH Dehydrogenation: an AIMD Study for Thermolysis.

How to improve the dehydrogenation properties of ammonia borane (AB, NHBH) is always a challenge for its practical application in hydrogen storage. In this study, we reveal the enhanced effect of an external electric field ( ) on AB dehydrogenation by means of the ab initio molecular dynamics method. The molecular rotation induced by an electrostatic force can facilitate the formation of the H-N···B-H framework, which would aggregate into poly-BN species and further suppress the generation of the volatile byproducts.

Anisotropic Reaction Properties for Different HMX/HTPB Composites: A Theoretical Study of Shock Decomposition.

Plastic-bonded explosives (PBXs) consisting of explosive grains and a polymer binder are commonly synthesized to improve mechanical properties and reduce sensitivity, but their intrinsic chemical behaviors while subjected to stress are not sufficiently understood yet. Here, we construct three composites of β-HMX bonded with the HTPB binder to investigate the reaction characteristics under shock loading using the quantum-based molecular dynamics method. Six typical interactions between HMX and HTPB molecules are detected when the system is subjected to pressure.

Quasi-Static Two-Dimensional Infrared Spectra of the Carboxyhemoglobin Subsystem under Electric Fields: A Theoretical Study.

There is no doubt that electric fields of a specific frequency and intensity could excite certain vibrational modes of a macromolecule, which alters its mode coupling and conformation. Motivated by recent experiments and theories, we study the mode coupling between the Fe-CO mode and CO-stretch mode and vibration energy transfer among the active site and proteins in carboxyhemoglobin (HbCO) under different electric fields using the quasi-static two-dimensional infrared spectra. This study uses iron-porphyrin-imidazole-CO and two distal histidines in HbCO as the subsystem.

[Role of macrophage migration inhibitory factor in septic shock-induced cardiovascular dysfunction: experiment with rats].

Objective: To investigate the role of macrophage migration inhibitory factor (MIF) in septic shock-induced cardiovascular dysfunction.

Methods: 56 SD rats were randomly divided into 7 equal groups: CLP group (undergoing cecal ligation and puncture so as to cause septic shock), CLP + ISO-1 group (ISO-1, was injected before and after CLP), CLP + MIF antibody group (MIF-Ab was injected before and after CLP), CLP + dexamethasone (DEX)-1, 5, and 20 groups [I, 5, or 20 mg/kg was injected 1 h after CLP), and sham operation group. Echocardiography was performed 6 h after CLP to measure the LVEDD, LVESD, FS%, CO, and PP.