Experimental Observation of Phase Transition in Sb203 under High Pressure

The in situ high-pressure behavior of the semiconductor antimony trioxide （Sb2O3） iS investigated by the Raman spectroscopy techniques and angle-dispersive synchrotron x-ray powder diffractfon in a diamond anvil cell up to 31.5 and 30.7 GPa, respectively. New peaks observed in the external lattice mode range in the Raman spectra at 13.5 GPa suggest that the structural phase transition occurs. The group mode （140 cm^-1） in Sb2O3 exhibits anomalous pressure dependence; that is, the frequency decreases gradually with the increasing pressure. High pressure synchrotron x-ray diffraction measurements at room temperature reveal that the transition from the orthorhombic structure to high-pressure new phase occurs at about 14.2 GPa, corresponding to the softening of the group optic mode （140cm^-1）.

Structural Phase Transitions of ZnTe under High Pressure Using Experiments and Calculations

The pressure-induced structural transitions of ZnTe are investigated at pressures up to 59.2 GPa in a diamond anvil cell by using synchrotron powder x-ray diffraction method. A phase transition from the initial zinc blende （ZB, ZnTe-Ⅰ） structure to a cinnabar phase （ZnTe-Ⅱ） is observed at 9.6 GPa, followed by a high pressure orthorhombic phase （ZnTe-Ⅲ） with Cmcm symmetry at 12.1 GPa. The ZB, cinnabar （space group P3121）, Cmcm, P31 and rock salt structures of ZnTe are investigated by using density functional theory calculations. Based on the experiments and calculations, the ZnTe-Ⅱ phase is determined to have a cinnabar structure rather than a P3 1 symmetry.

Experimental study of compressible boundary layer on a cone at angles of attack

Experimental study was conducted for boundarylayers on a sharp 5° half-angle cone of 400mm length at angles of attack. The model was tested in the T-326 hypersonic wind tunnel （ITAM） at freestream Mach number M = 5.95. Mean and fluctuation wall characteristics of the boundary layer are measured at 0°, 2°, 3° and 4° angles of attack for different stagnation pressures. Pulsation measurements are carried out by means of ALTP sensor. Pressure and temperature distributions along the model are obtained, and transition beginning and end locations have been found. Boundary layer stabilization with the increase of angle of attack and the decrease of stagnation pressure is observed. High frequency pulsations inherent to hypersonic boundary layer （second mode） have been detected.

Deflagration-to-detonation transition process for spherical aluminum dust/epoxypropane mist/air mixtures in a large-scale experimental tube

The deflagration-to-detonation transitions (DDTs) for clouds of spherical aluminum dust (SAD) mixed with air or epoxypropane mist (EPM) and air were investigated in a 29.6-m-long experimental tube of 199 mm in diameter. The clouds formed through the injection of SAD and SAD/liquid epoxypropane samples into the experimental tube. Explosions of the SAD/air mixture were initiated using a 7-m-long EPM/air cloud explosion ignited by a 40-J electric spark. Explosions in SAD/EPM/air clouds were initiated using a 1.2-m EPM/air cloud explosion ignited by a 40-J electric spark initiated using a 40-J electric spark. Self-sustained detonation waves formed in SAD/EPM/air mixtures instead of in SAD/air mixtures. The stages and characteristics of the DDT process in SAD/air and SAD/EPM/air mixtures were studied and analyzed. Self-sustained detonation was evident from the existence of a transverse wave and a cellular structure. Moreover, a retonation wave formed during the DDT process in SAD/EPM/air clouds.

Deformed dispersion relation constraint with hydrogen atom 1S-2S transition

We use the latest results of the ultra-high accuracy 1S-2S transition experiments in the hydrogen atom to constrain the forms of the deformed dispersion relation in the non-relativistic limit.For the leading correction of the non-relativistic limit,the experiment sets a limit at an order of magnitude for the desired Planck-scale level,thereby providing another example of the Planck-scale sensitivity in the study of the dispersion relation in controlled laboratory experiments.For the next-to-leading term,the bound is two orders of magnitude away from the Planck scale,however it still amounts to the best limit,in contrast to the previously obtained bound in the non-relativistic limit from the cold-atom-recoil experiments.