We demonstrate an efficient approach to realizing an extra-cavity, synchronously pumped, stimulated Raman cascaded process under low repetition frequency (1 kHz) pump conditions. We also construct a compact KGd(WO4)2 (KGW) crystal picosecond Raman laser that has been configured as the developed method. A pulse-train green laser pumped the corresponding 70 mm long KGW crystal Raman cavity. The pulse train contains six pulses, about 800 ps separated, for every millisecond; thus, it can realize synchronous pumping between pump pulse and the pumped Raman cavity. The investigated system produced a collinear Raman laser output that includes six laser lines covering the 532 to 800 nm spectra. This is the first report on an all-solid-state, high-average-power picosecond collinear multi-wavelength (more than three laser components) laser to our knowledge. This method has never been reported on before in the synchronously pumped stimulated Raman scattering (SRS) realm.
In construction, concrete compatibility is an important comprehensive index to ensure the construction, and the concrete slump is an important criterion to judge concrete compatibility in the actual construction process. In this study, we propose to extract new data sets from concrete mixing video sequences and correlate the image features characterized in the concrete mixing and transportation process with the concrete performance features, starting from the concrete transportation process [1]. First, the UNet network model for semantic segmentation is used to identify and locate the concrete regions, and the localized concrete regions are zoomed in using interpolation; then the ResNet image classification network is used to determine the slump category of the processed concrete regions; finally, the results of the semantic segmentation network and the image classification network are fused to obtain the final concrete slump detection results. The experimental results demonstrate that the proposed method can guarantee real-time concrete slump detection with improved accuracy.
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