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The pump source, gain material, and resonant cavity are the three elements that make up a laser. Due to the selective effect of the resonant cavity on the lasing frequency, multi longitudinal mode operation is one of the characteristics of fiber lasers based on traditional resonant cavity structures, manifested as periodic beat peaks in the radio frequency (RF) spectrum and periodic fluctuations i...
Recently, Zhang Xin's research team from the Institute of Oceanography, Chinese Academy of Sciences, based on the in-situ laser Raman spectroscopy technology, made new progress in the in-situ recognition and quantification of methane carbon isotopes by using the significant differences in the Raman spectra of methane carbon isotopes (13CH4 and 12CH4). The relevant results were recently published i...
IntroductionThe small hole mode swing laser welding has gained increasing recognition due to its ability to bridge gaps, refine microstructures, and enhance the mechanical properties of welds. However, the effects of amplitude, frequency, welding speed, laser beam power, and beam radius on heat flux distribution, melting mode, and three-dimensional temperature field have not been well understood. ...
The fully 3D printed electric spray engine is suitable for small satellite in orbit maneuver, and its production cost is only a small part of that of traditional thrusters.Image source: Massachusetts Institute of Technology, USAThe Massachusetts Institute of Technology team recently demonstrated an electric spray engine made entirely of 3D printing technology, which can be propelled by emitting ...
According to a recent study published in the journal Science Advances, it reveals how early mammals grew and developed during critical periods of their long 'life history'. A research team including Queen Mary University of London used synchrotron X-ray tomography technology to image the growth rings in fossilized tooth roots, in order to infer the lifespan, growth rate, and even sexual maturity t...