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To further explore the metabolism of Lycium barbarum polysaccharides, the cell wall microstructure of Lycium barbarum fruits in different growth periods was observed by transmission electron microscopy, and the cell wall polysaccharide content and its degrading enzyme activity were extracted by chemical method. The changes of polysaccharide components in cell wall of Lycium barbarum fruits in different growth periods were analyzed by microcopolymer Raman spectroscopy. The correlation between the content of polysaccharide in cell wall and the activity of degrading enzyme was analyzed. The results showed that the changes of cell wall structure mainly occurred during 28~35 d, with the cell wall becoming significantly thinner, pectin degrading, and the cell wall structure gradually collapsing. Cell wall material (CWM) content increased first and then decreased, and water-soluble pectin (WSP) content increased significantly (P

In order to study the distribution characteristics of the “three zones” of coal spontaneous combustion in the goaf of double cut roof retained roadway, taking the working face 4502 of Shaqu No.1 Mine as the engineering background, a combination of on-site monitoring and numerical simulation was adopted to study the air leakage law and the distribution characteristics of the “three zones” of coal spontaneous combustion in the goaf of the working face 4502 with double cut roof retained roadway. The results show that the main air leakage areas in the goaf of the double cut roof retaining roadway are the corners of the working face and the retaining roadways on both sides. The air flow mainly leaks into the goaf from the corners on both sides, and there is air exchange between the goaf and the retaining roadways on both sides. There is a slender oxidation zone on the side of the double retaining roadway, and the oxidation zone is distributed in a U-shaped throughout the goaf. At different stages of mining, there are significant differences in the distribution of the “three zones” of coal spontaneous combustion in the working face with double cut roof retaining roadway. In the initial stage of mining, it is necessary to strengthen the prevention and control of coal spontaneous combustion within a range of 5 m on the side of the double cut roof retaining roadway and 32-65 m in the middle of the goaf. In the middle and later stages of mining, it is necessary to strengthen the prevention and control of coal spontaneous combustion within a range of 2.5 m on the side of the transportation retaining roadway, within a range of 12 m after 38 m from the track retaining roadway, and within a range of 30-80 m in the middle of the goaf.

This paper reviews the multiple rounds of upgrades of the hydraulic fracturing technology used in the Gulong shale oil reservoirs and gives suggestions about stimulation technology development in relation to the production performance of Gulong shale oil wells. Under the control of high-density bedding fractures, fracturing in the Gulong shale results in a complex fracture morphology, yet with highly suppressed fracture height and length. Hydraulic fracturing fails to generate artificial fractures with sufficient lengths and heights, which is a main restraint on the effective stimulation in the Gulong shale oil reservoirs. In this regard, the fracturing design shall follow the strategy of “controlling near-wellbore complex fractures and maximizing the extension of main fractures”. Increasing the proportions of guar gum fracturing fluids, reducing perforation clusters within one fracturing stage, raising pump rates and appropriately exploiting stress interference are conducive to fracture propagation and lead to a considerably expanded stimulated reservoir volume (SRV). The upgraded main hydraulic fracturing technology is much more applicable to the Gulong shale oil reservoirs. It accelerates the oil production with a low flowback rate and lifts oil cut during the initial production of well groups, which both help to improve well production. It is suggested to optimize the hydraulic fracturing technology in six aspects, namely, suppressing propagation of near-wellbore microfractures, improving the pumping scheme of CO2, managing the perforating density, enhancing multi-proppant combination, reviewing well pattern/spacing, and discreetly applying fiber-assisted injection, so as to improve the SRV, the distal fracture complexity and the long-term fracture conductivity.

In order to improve the mechanical properties, water resistance and barrier properties of rice bran protein (RBP) film, glycosylated RBP (RBP-G) film and RBP-G-chitosan composite (RBP-G-CS) film were prepared. The effects of the mass ratio of glucose to RBP and the mass ratio of RBP-G to chitosan on the mechanical properties of the films were investigated. The color, transparency, water resistance, water vapor permeability and thermal characteristics of RBP, RBP-G and RBP-G-CS films prepared under the optimal conditions were compared and analyzed. The structure of the films was characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The results showed that the mechanical properties of RBP-G film with a glucose to RBP ratio of 1:1 were obviously improved, and the tensile strength increased by 28.00% and the elongation at break by 33.13% compared with RBP film. RBP-G-CS film with a RBP-G to chitosan ratio of 1:1 had better mechanical properties, and its tensile strength and elongation at break increased by 197.33% and 84.42% compared with RBP film, respectively. The transparency, water resistance, barrier properties and thermal properties of RBP-G-CS film were significantly improved (P < 0.05). The structure of RBP-G-CS film was uniform and compact, owing to the strong hydrogen bonding forces. These results show that glycosylation modification can improve the performance of RBP film, and a good combination of modified RBP and chitosan can greatly improve the mechanical properties and water resistance of the film.

The original MTRNN query algorithm dose not filter any data in the search space, so it is very inefficient. Based on MTRNN query, this paper developed a closed region and open region pruning strategy with R-tree, and then presented a filtering algorithm to reduce the search space by constructing closed regions and open regions. The filtering effect of the algorithm was obvious on large data for MTRNN queries. Finally, the experimental results demonstrate the filtering algorithm's effectiveness. [ABSTRACT FROM AUTHOR]

This study proposed a non-destructive method for rapid freshness evaluation of green bean based on Raman spectroscopy. The Raman spectra of green bean with different storage times were collected, its physicochemical indicators reflecting changes in freshness including mass loss rate, total color difference (∆E), hardness, ascorbic acid content and chlorophyll content were measured, and chemometrics methods were used to associate the spectral data with the physicochemical data. The effectiveness of different spectral pretreatments such as baseline correction (BL), Gaussian filter (GF), normalization (NL) and standard normal variable (SNV) was compared, and partial least squares regression (PLSR) and principal component regression (PCR) were used individually to establish freshness prediction models will all or selected wavenumbers. Moreover, the regression coefficient (RC) method was used to select the characteristic Raman wavenumbers. The simplified PLSR model for each freshness indicator showed a correlation coefficient of calibration set (rc) of greater than 0.92, a correlation coefficient of prediction set (rp) of greater than 0.89, and a residual predictive deviation (RPD) of greater than 2.0. The rc and rp of the PCR model were greater than 0.79 and 0.73, respectively. Therefore, the results of this study indicate that Raman spectroscopy allows non-destructive and rapid detection of the freshness of green bean.