Optical sampling based on ultrafast optical nonlinearities is a useful technique to monitor the waveforms of ultrashort optical pulses. In this paper, we present a new implementation of optical waveform sampling systems by employing our newly constructed free-running mode-locked fibre laser with a tunable repetition rate and a low timing jitter, an all-optical waveform sampler with a highly nonlinear fibre (HNLF), and our developed computer algorithm for optical waveform display and measurement, respectively. Using a femtosecond fibre laser to generate the highly stable optical sampling pulses and exploiting the four-wave mixing effect in a 100 m-long HNLF, we successfully demonstrate the all-optical waveform sampling of a 10 GHz optical clock pulse sequence with a pulse width of 1.8 ps and a 80 Gbit/s optical data signal, respectively. The experimental results show that waveforms of the tested optical pulse signals are accurately reproduced with a pulse width of 2.0 ps. This corresponds to a temporal resolution of 0.87 ps for optical waveform measurement. Moreover, the optical eye diagram of a 10Gbit/s optical data signal with a 1.8 ps pulse width is also accurately measured by employing our developed optical sampling system.
Due to the characteristics of color vegetation canopy images which have multiple details and Gaussion noise interference, the adaptive mean filtering (AMF) algorithm is used to perform the denoising experiments on noised images in RGB and YUV color space. Based on the single color characteristics of color vegetation canopy images, a simplified AMF algorithm is proposed in this paper to shorten the overall running time of the denoising algorithm by simplifying the adaptive denoising processing of the component V, which contains less image details. Experimental results show that this method can effectively reduce the running time of the algorithm while maintaining a good denoising effect.
The friction and wear properties of 201HT aluminum alloys and the corresponding competitive coupons were tested on an electrohydraulic
servo face friction and wear testing machine (MM-U10G). The microstructures of the competitive coupons were investigated by
scanning electron microscopy (SEM) and consequently the corresponding friction and wear mechanisms were studied. The results
demonstrated that: (1) the best competitive material of friction and wear performance of the 201HT was the 201HTC. (2) the 201HTC
modified by carbon following the initial mill for oil storage of the micro-groove to be produced, increased the corresponding lubrication
performance reduced the friction coefficient and wear rate effectively. (3) the 201HT-201HTC could obtain both better friction and wear
mainly due to the initial process of grinding following the 201HT plastic deformation occurred in the surface and the formation of a series
of re-melting welding points, whereas the 201HT material hardness would be similar to the 201HTC material hardness, which led into the
competitive material friction and wear performance improvement.
Telomerase reverse transcriptase (TERT) vectors were transfected into bone marrow mesen- chymal stem cells (BMSCs) which were then cultured and selected to establish TERT-BMSC cell lines whilst sequencing BMSCs and TERT-BMSCs via transcriptome in this study to explore their regulatory mechanism and effect on osteogenic differentiation after TERT ectopic expres- sion in sheep BMSCs. After sequencing and analysing differential genes, PI3K/Akt signalling pathway related to osteogenic differentiation was investigated. Western blot was used before and after applying the PI3K/Akt signalling pathway inhibitor LY294002 to detect protein expression levels of AKT and p-AKT. On the twenty-first day of osteogenic differentiation, RT-qPCR and Western blot were used to detect mRNA and protein expression levels of RUNX2 and OPN and alizarin red staining was utilised to analyse calcium salt deposition. Results showed that pro- tein expression levels of AKT and p-AKT were significantly up-regulated, mRNA and protein expression levels of RUNX2 and OPN increased and calcium salt deposition increased after ectopic expression of TERT. After applying LY294002, the protein expression of AKT and p-AKT was down-regulated, mRNA and protein expression levels of RUNX2 and OPN were reduced and calcium salt deposition was reduced. These results confirmed the stable integration and expression of the exogenous TERT gene in BMSCs to promote the differentiation of BMSC osteoblasts, which may be mediated by the PI3K/Akt signalling pathway.
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