ABSTRACT
The rocket sled, as a ground dynamic test system, combines the characteristics of the wind tunnel test and the flight test. However, some practical factors, such as shock wave interference, ground effect, and high-intensity aerodynamic noise will cause serious interference and even failure of the uniformly distributed sensors during horizontal sliding in a wide speed range. The AGARD HB-2 standard model is employed as the payload to simulate the aerodynamic and aeroacoustic characteristics during the variable acceleration period, aiming to optimize the test sensors layout. It is observed that in the high Mach number flow fields, strong coupling behaviors among complex waves will occur. The peak of wake vortex strength will appear at 1.5 s and gradually diminish over time. In addition, when the vortex between the load and the booster is monitored, its position shifts forward in the subsonic stage, then gradually moves backward and expands in the supersonic stage. Acoustic directivity is pronounced at subsonic and transonic speeds, pointing towards 75° and 135° relative to the sliding speed, respectively. These results can provide technical support for sensor layout and high-precision testing in rocket sled tests.
ABSTRACT
In this work, sol-gel and chemical etching methods are adopted to synthesize zinc hydroxystannate materials. Cubic tin dioxide and zinc stannate composite materials with a definite structure are successfully prepared at varied annealing temperatures and times by using the synthesized zinc hydroxystannate as a sacrificial template. After a gas sensing test, tin dioxide and zinc stannate composite samples etched at 650 °C and annealed for 4 h exhibit a strong response and outstanding selectivity to hydrogen peroxide. Furthermore, the samples prepared under such conditions demonstrate long-term stability, and also a specified level of tolerance after the humidity stability test. Moreover, because of the simple preparation method and rapid detection of hydrogen peroxide, it is worth noting that samples prepared following the etching process at the 650 °C annealing temperature for 4 h exhibit the significant benefits of tin dioxide and zinc stannate composites. In this modern era, this research emphasizes the sample's potential for the rapid identification and detection of hydrogen peroxide.