Abstract: In this experimental study, I have seen that a comparative study on semiconductor laser and Helium-Neon laser is presented using the experimental techniques and tried to compare the experimental value with that of the theoretical one. On this work the wave length and beam divergence angle of the two types of lasers up to ten number of trials in the three orders, starting from 20cm to 200cm, with an interval of 20cm for each order was measured and I found that in the first and second order in the two types of laser, the wave length and the divergence angle is greater for Helium-Neon laser than semiconductor laser, thus, from this it is possible to understand that semiconductor laser is highly directional, means that it has high intensity, whereas, in the third order the Helium-Neon laser is not visible but semiconductor laser is visible, which is one of the indicator of Helium-Neon laser is not highly directional. And again, I examine that the beam divergence angle and wave length can have inverse relationship for the two types of lasers, as we see from figures 3 and 4. Thus, we concluded that the experimental result is almost agreed with that of the theoretical one.Abstract: In this experimental study, I have seen that a comparative study on semiconductor laser and Helium-Neon laser is presented using the experimental techniques and tried to compare the experimental value with that of the theoretical one. On this work the wave length and beam divergence angle of the two types of lasers up to ten number of trials in the...Show More
Abstract: The propagation characteristics and rock breaking mechanism of explosive stress wave have aroused the interests of many researchers. This work proposed a method that separates the explosion stress wave from detonation gas and designed the testing unit accordingly. It combined the resistance ultra-dynamic strain test to conduct the strain measurement on local key points and obtained the strain waveforms of representative measuring points under the explosion stress wave. The characteristics of these strain waveforms were analyzed and the energy-based spectral analysis of these waveforms was done using Matlab. Findings show that both strain peak and stress rate peak are the biggest along the slot direction, followed by that along the non-slot direction, 135° direction and 45° direction in a descending order; the similar low-frequency band was detected at the measuring point with the same distance to the explosion source, while the high-frequency band was unevenly distributed. In the rock breaking experiment under the stress wave of slotted cartridge, with regards to the measuring points at the same distance to borehole, the similar low-frequency bands appeared and concentrated in 292.8-448Hz. The included angle between each measuring point and the slot was different, which impacted the propagation of stress wave to some extent and resulted in uneven distribution of the high-frequency bands.Abstract: The propagation characteristics and rock breaking mechanism of explosive stress wave have aroused the interests of many researchers. This work proposed a method that separates the explosion stress wave from detonation gas and designed the testing unit accordingly. It combined the resistance ultra-dynamic strain test to conduct the strain measuremen...Show More
