Investigation of flow field characteristics and performance of carbon-hydrogen/oxygen-rich air rotating detonation engine

Numerical simulations were conducted to investigate the flow field characteristics and performance of a carbon-hydrogen/oxygen-rich air rotating detonation engine (RDE). Three distinct flow field structures were observed in the gas-solid two-phase RDE. The results show that reducing the hydrogen equivalence ratio and particle diameter both contribute to the transition from gas-phase single-front detonation to gas-solid two-phase double-front detonation and further to gas-solid two-phase single-front detonation. The effects of solid fuel particle diameter and hydrogen equivalence ratio on the flow field characteristics and performance are revealed. The results show that reducing the particle diameter enhances the speed of the two-phase detonation wave, improves the pressure gain in the combustion chamber, and increases the specific impulse. Decreasing the hydrogen equivalence ratio reduces the detonation wave speed, enhances the stability of the detonation flow field, increases the pressure gain in the detonation wave and combustion chamber and boosts thrust. Furthermore, the selection of operational conditions to ensure stable operation and optimal performance of the RDE is discussed. In order to take into account the requirements of stability, pressure gain performance and propulsion performance, two-phase single-front detonation should be realized in gas-solid two-phase RDE, and smaller hydrogen equivalent ratio and appropriate particle diameter should be selected. According to the conclusion of this study, the particle diameter should be 0.5-1 {\mu}m. Under such conditions, the detonation flow field demonstrates good stability, allowing the RDE to achieve higher pressure gain and specific impulse while maintaining stable operation

A comparative study of prepulse inhibition in children with first episode schizophrenia and normal children

Objective·To explore the characteristics of sensory gating and its variation in children with first episode schizophrenia (COS) by using a new technique of prepulse suppression (PI).Methods·By using the ERP recording and analysis system of brain products, PI was detected in 56 patients with COS and 38 healthy children (NC) using the paradigm of single strong stimulus and weak stimulus+strong stimulus. The patients′ performance was comprehensively evaluated with Positive and Negative Syndrome Scale (PANSS), Social Disability Screening Schedule (SDSS), Social Adjustment Rating Scale (SSRS), and Family Interview Schedule (FIS).Results·The social objective support formed by summing up the above scales was compared with the quantitative stanard of social support [the standard of social support scale was (8±2) points, and the value of COS group was (10±3) points], and the difference was statistically significant (P=0.007). No correlation was found between PI and PANSS total score and each factor score (all P>0.05). The latency of startle reflex in the COS group was longer than that in the NC group [the NC group was (86±11) ms, the COS group was (97±13) ms, P=0.001]. In the COS group, the amplitude of startle reflex of weak stimulus+strong stimulus was higher, and the latency was longer than that of the NC group [NC group: (39±12) μV, COS group (47±21) μV, P=0.007; the latency of the normal group was (84±17) ms, and that of the COS group was (97±20) ms, P=0.003]. PI inhibition rate in the COS group was lower than that in the NC group [(66±32) % in the NC group, (43±37) % in the COS group, P=0.000].Conclusion·COS patients have the same PI abnormality as adult schizophrenia. The change of PI inhibition may be the result of biological markers reflecting the change of agitated emotion in COS patients