287 research outputs found

    Using the FY-3E satellite hyperspectral infrared atmospheric sounder to quantitatively monitor volcanic SO2

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    The Hyperspectral Infrared Atmospheric Sounder Type II (HIRAS-II) aboard the Fengyun 3E (FY-3E) satellite provides valuable data on the vertical distribution of atmospheric states. However, effectively extracting quantitative atmospheric information from the observations is challenging due to the large number of hyperspectral sensor channels, inter-channel correlations, associated observational errors, and susceptibility of the results to influence by trace gases. This study explores the potential of FY-3E/HIRAS-II to atmospheric loadings of SO2 from volcanic eruption. A methodology for selecting SO2 sensitive channels from the large number of hyperspectral channels recorded by FY-3E/HIRAS-II is presented. The methodology allows for the selection of SO2-sensitive channels that contain similar information on variations in atmospheric temperature and water vapor for minimizing the influence of atmospheric water vapor and temperature to SO2. A sensitivity study shows that the difference in brightness temperature between the experimentally selected SO2 sensitive channels and the background channels effectively removes interference signals from surface temperature, atmospheric temperature, and water vapor during SO2 detection and inversion. A positive difference between near-surface atmospheric temperature and surface temperature enables the infrared band to capture more SO2 information in the lower and middle layers. The efficacy of FY-3E/HIRAS-II SO2 sensitive channels in quantitively monitor volcanic SO2 is demonstrated using data from the 29 April 2024 eruption of Mount Ruang in Indonesia. Using FY-3E/HIRAS-II measurements, the spatial distribution and quantitatively information of volcanic SO2 are easily observed. The channel selection can significantly enhance the computation efficiency while maintain the accuracy of SO2 detection and retrieval, despite the large volume of data

    Effects of experimental parameters on elemental analysis of coal by laser-induced breakdown spectroscopy

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    The purpose of this work is to improve the precision of the elemental analysis of coal using laser-induced breakdown spectroscopy (LIBS). The LIBS technique has the ability to allow simultaneous elemental analysis and on-line determination, so it could be used in the elemental analysis of coal. Organic components such as C, H, O, N and inorganic components such as Ca, Mg, Fe, Al, Si, Ti, Na, and K of coal have been identified. The precision of the LIBS technique depends strongly on the experimental conditions, and the choice of experimental parameters should be aimed at optimizing the repeatability of the measurements. The dependences of the relative standard deviation (RSD) of the LIBS measurements on the experimental parameters including the sample preparation parameters, lens-to-sample distance, sample operation mode, and ambient gas have been investigated. The results indicate that the precision of LIBS measurements for the coal sample can be improved by using the optimum experimental parameters

    Matrix Effect on Laser Induced Breakdown Spectroscopy of Fine Coal

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    peer reviewedThe feasibility of laser—induced breakdown spectroscopy as a diagnostic tool for elementary analysis was documented widely,as well as the matrix effect of target material was proved to be remarkable impact on the spectral analysis. The influence of physical characteristics of fine coal,including particle size and area density,on the emission spectrum was surveyed,such as spectral intensity,standard deviation of characteristic spectrum and the detection threshold.An intense laser radiation with a wavelength of 1064 nm was used to ablate fine coal to form plasma plume,and the emission spectrum emitted as the plasma cooling of was analyzed by high—resolution echelle grating spectrometer coupled to intensified CCD camera.The results suggest that moderate particle size and material density are more advantageous to quantitative analysis of coal by laser—induced breakdown spectroscopy than the smallest or biggest size,which can be interpretable by heat—transfer mechanism in target after a shot of laser pulse

    Influence of coal characteristics on laser-induced plasmas

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    peer reviewedEight kinds of typical coal samples were chosen for studying the influence of coal characteristics on laser—induced plasmas.Element analysis and industry analysis were carried out for every sample.Experimental study on the interaction between laser and different coal samples was completed,and factors affecting laser plasma were analyzed,such as coal moisture and coal dust.The experiment result indicates that the coal samples with different coalification degrees have different plasma time—resolved spectral characteristics,all of them tend to rise at the beginning of plasma formation (< 1us),then with the decay of plasmas emission.they tend to decrease in about 1us,while secondary ionization occurs in highly coalificated coals after 2 us.The plasma temperature differs from one kind to another,the higher the coalification degree is,the higher the plasma temperature will be

    Effect of Ultra-fast chilling on the expression of glycolytic enzymes in fresh mutton

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    The pH value, glucose content, glycolytic potential, and expression levels of five glycolytic enzymes in lamb longissimus dorsi muscle at different time after slaughter were compared and analyzed, which treated at different cooling rates and stored at different temperatures. The impact of two steps in the process of ultra-fast chilling on the expression levels of glycolytic enzymes was determined. The regulatory mechanism of ultra-fast chilling on the glycolytic rate was elucidated from the perspective of protein expression. The results showed that ultra-fast chilling treatment significantly delayed the decrease of pH and the increase of glycolytic rate, promoted the expression levels of aldolase (ALDOA), glycogen phosphorylase (PYGM), and triosephosphate isomerase (TPI1), and inhibited the expression levels of phosphofructokinase (PFKM) and phosphoglycerate kinase (PGK). After cooling treatment, refrigeration and controlled freezing-point storage delayed glycolysis by inhibiting the expression level of PGK, without altering the effect of ultra-fast chilling. The expression level of PFKM was positively correlated with the rate of glycolysis at different temperatures. It was found that different glycolytic enzymes had different responses to temperature changes. Ultra-fast chilling affected energy supply and demand by changing the expression of enzymes involved in glycolysis. The high expression level of PFKM was associated with fast glycolysis. PFKM can be regarded as a key enzyme in the ultra-fast chilling process

    Recent Advances in Soft Biological Tissue Manipulating Technologies

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    Biological soft tissues manipulation, including conventional (mechanical) and nonconventional (laser, waterjet and ultrasonic) processes, is critically required in most surgical innervations. However, the soft tissues, with their nature of anisotropic and viscoelastic mechanical properties, and high biological and heat sensitivities, are difficult to manipulated. Moreover, the mechanical and thermal induced damage on the surface and surrounding tissue during the surgery can impair the proliferative phase of healing. Thus, understanding the manipulation mechanism and the resulted surface damage is of importance to the community. In recent years, more and more scholars carried out researches on soft biological tissue cutting in order to improve the cutting performance of surgical instruments and reduce the surgery induced tissue damage. However, there is a lack of compressive review that focused on the recent advances in soft biological tissue manipulating technologies. Hence, this review paper attempts to provide an informative literature survey of the state-of-the-art of soft tissue manipulation processes in surgery. This is achieved by exploring and recollecting the different soft tissue manipulation techniques currently used, including mechanical, laser, waterjet and ultrasonic cutting and advanced anastomosis and reconstruction processes, with highlighting their governing removal mechanisms as well as the surface and subsurface damages

    Acetylation and Phosphorylation Regulate the Role of Pyruvate Kinase as a Glycolytic Enzyme or a Protein Kinase in Lamb.

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    peer reviewedProtein post-translational modifications (PTMs) play an essential role in meat quality development. However, the effect of specific PTM sites on meat proteins has not been investigated yet. The characteristics of pyruvate kinase M (PKM) were found to exhibit a close correlation with final meat quality, and thus, serine 99 (S99) and lysine 137 (K137) in PKM were mutated to study their effect on PKM function. The structural and functional properties of five lamb PKM variants, including wild-type PKM (wtPKM), PKM_S99D (S99 phosphorylation), PKM_S99A (PKM S99 dephosphorylation), PKM_K137Q (PKM K137 acetylation), and PKM_K137R (PKM K137 deacetylation), were evaluated. The results showed that the secondary structure, tertiary structure, and polymer formation were affected among different PKM variants. In addition, the glycolytic activity of PKM_K137Q was decreased because of its weakened binding with phosphoenolpyruvate. In the PKM_K137R variant, the actin phosphorylation level exhibited a decrease, suggesting a low kinase activity of PKM_K137R. The results of molecular simulation showed a 42% reduction in the interface area between PKM_K137R and actin, in contrast to wtPKM and actin. These findings are significant for revealing the mechanism of how PTMs regulate PKM function and provide a theoretical foundation for the development of precise meat quality preservation technology
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