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A severe convective weather event occurred in the Arksu area of Xinjiang on 7 June 2017. In this event, two α-mesoscale convection systems (MCS) and their merging and development caused gale, hailstorm, and short-time heavy precipitation at several stations. The objective of this study is to determine the distribution characteristics of cloud-to-ground (CG) lightning and its relationship with cloud top brightness temperature (TBB) and the development of radar echo and convective system in this event, and to deepen the understanding of the characteristics of CG lightning activity. Using the lightning locating data over Xinjiang, the TBB data from FY-4A, the Doppler weather radar data, and other data, we conducted an analysis of the characteristics of CG lightning activity during this event. The results show that (1) the CG lightning activity concentrates on the warm advection side of the low-level shear line due to the obviously wetter lower and middle troposphere and the stability and continuance of the mesoscale shear line in the lower troposphere. (2) During the event, the CG lightning is mainly negative CG lightning, and its intensity is higher in the east and lower in the west of the Arksu area. There is a certain negative correlation between the CG lightning intensity and the CG lighting density. The large-scale strong wind near the ground has a strong linear correlation with the leap of CG lightning frequency and the decreasing of positive CG lightning proportion. (3) Most of CG lightning distributes in the areas where TBB is less than or equal to -40℃. The frequency of CG has positive and negative correlations with the cloud cluster areas with TBB ≤ -40℃ and the TBB minimum value, respectively. (4) During the period affected by MCS, most of the negative and positive CG lightning occur in the echo areas of 6-20 dBz and 11-15 dBz, respectively. Both the generation and development and the mature stages of convection, the peak value of vertical integrated liquid water content (VIL) appears 12-20 min earlier than the sharp increasing of CG lightning frequency. There are positive and negative correlations between CG lightning frequency and echo top height at the generation and development and the mature stages of convection, respectively.

The Central Asian vortex is a cut-off vortex system with regional characteristics formed under the background of arid climate and unique geographical structure in Central Asia. It has an important impact on the weather and climate in Xinjiang, and even the weather and climate in the Middle East of China. Since 1960s, Chinese meteorologists have conducted preliminary research on its synoptic characteristics. Until 2000, with the continuous enrichment of observation data and the development of meteorological theory, Chinese meteorologists have conducted in-depth research on its definition, classification, activity characteristics, formation mechanism and its impacts on heavy precipitation in Xinjiang. This study reviews and summarizes the research on the Central Asian vortex system and its influence mechanism on precipitation in Xinjiang in recent 20 years. This study also reviews the synoptic condition and water vapor characteristics of typical rainstorm weather, the mesoscale system related to rainstorm and short-term heavy rainfall, and the synergy of rainstorm multi-scale weather system under the background of the Central Asian vortex, and puts forward the scientific problems that need to be further studied in the end.

This paper addresses the problem of high-resolution imaging of shadowed multiple-targets with limited labeled data, by proposing a transfer-learning-based method for through-the-wall radar imaging. First, a generative adversarial sub-network is developed to facilitate the migration of labeled simulation data to measured data, overcoming the difficulty of generating labeled data. This method incorporates an attention mechanism, adaptive residual blocks, and a multi-scale discriminator to improve the quality of image migration. It also incorporates a structural consistency loss function to minimize perceptual differences between images. Finally, the labeled data are used to train the through-the-wall radar target-imaging sub-network, achieving high-resolution imaging of multiple targets through walls. Experimental results show that the proposed method effectively reduces discrepancies between simulated and obtained images, and generates pseudo-measured images with labels. It systematically addresses issues such as side/grating ghost interference, target image defocusing, and multi-target mutual interference, significantly improving the multi-target imaging quality of the through-the-wall radar. The imaging accuracy achieved is 98.24%, 90.97% and 55.17% for single, double, and triple-target scenarios, respectively. Compared with CycleGAN, the imaging accuracy for the corresponding scenarios is improved by 2.29%, 40.28% and 15.51%, respectively.

This study evaluated the juice processing characteristics of seven typical blueberry fruit cultivars: Windsor, Susieblue, Lanmei 1, Sharpblue, Sweetheart, Titan, and Gardenblue from three major strains (Southern highbush, Northern highbush and rabbiteye). The juice yield, color, physicochemical properties, functional component contents and antioxidant capacities were analyzed. In addition, correlation, factor, and cluster analyses were used to evaluate comprehensively the suitability of each cultivar for juice processing. The results indicated significant differences in the juice processing characteristics of the blueberry cultivars (PTitan>Lanmei 1>Windsor>Sharpblue>Susieblue>Sweetheart. Among the seven blueberry cultivars, the most suitable for juice processing was Gardenblue, followed by Titan. This study provides a theoretical reference for selecting blueberry cultivars for juice processing.

In order to improve the drying quality of rice, Indica and japonica hybrid rice were taken as the object and evaluated by waist burst rate, head rice rate, energy consumption and drying time in this experiment. Single factor and response surface analysis were combined to optimize the drying process. The effects of variable temperature-tempering drying on proteins structure and thermal properties of indica and japonica hybrid rice were investigated by differential scanning calorimetry. Fourier infrared spectroscopy and fluorescence spectroscopy. The results showed variable temperature-tempering drying (temperature range 30~60 ℃) that under the conditions of temperature rise 5 ℃, wind speed 1 m/s and tempering ratio 0.6, the rice could be kept in the glassy state, and the waistband burst rate and head rice rate after drying were 79.89% lower and 39.54% higher than those in the constant temperature group (60 ℃), respectively. Under these conditions, the polarity of rice proteins decreased and intermolecular aggregation occured, which improved the thermal stability of rice proteins, and the α-helix content increased from 16.21% to 17.64%. Scanning electron microscope results showed that the surface structure of protein was not significantly affected by variable temperature-tempering drying. The experiment explored and verified the drying mechanism of hybrid rice with variable temperature-tempering drying, which would provide a theoretical and practical reference for the research of high quality drying of hybrid rice.

In order to investigate the effects of different storage temperatures on the storage quality and enzyme activities of Fritillaria thunbergii Miq from the soil, which were stored at 0, 5, 10 and 20 ℃ for 90 d. The changes in weight loss, sensory quality, color, hardness, total polysaccharides, alkaloids, malondialdehyde (MDA) contents, polyphenol oxidase (PPO), peroxidase (POD) and superoxide dismutase (SOD) activities of Fritillaria thunbergii Miq were explored at different storage temperatures. The results showed that the weight loss rate of Fritillaria thunbergii Miq at 0 ℃ for 90 d was only 7.17%, which was significantly lower than that at 5, 10 and 20 ℃ (9.92%, 19.77% and 30.28%) (P

This study analyzed the differential composition between from concentrate (FC) and not from concentrate (NFC) bayberry juices by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). NFC and FC bayberry juice were distinguished from each other by orthogonal partial least squares discriminant analysis, and 9 compounds that significantly differed in abundance between them were selected and identified according to the variable importance in the projection and the fold-change. By comparison, the content of antioxidant active components such as 4-sulfobenzoate, 5-methyltetrahydrofolic acid, cyanidin, daphnoretin, xanthotoxol and isoxanthopterin in FC bayberry juice were relatively low, whereas the bitter substances (neohesperidin, hesperidin and quercetin-3-O-neohesperidin) were relatively high. Metabolic pathways were analyzed on account of differential metabolites and five metabolic pathways with great differences were identified, among which phenylalanine metabolism, biosynthesis of flavonoids and flavonols were the key metabolic pathways of different metabolites in NFC and FC bayberry juice. This study revealed the difference of metabolites between NFC and FC bayberry juice, which provided theoretical reference for the processing and identification of NFC bayberry juice.

Fruit maturity is a major factor associated with the final juice’s flavor quality. To explore the flavor changes and differences of the honey peach juice processed from different maturities, ‘Hujingmilu’ honey peaches from three different maturities were selected for the study. Flavor profiles of honey peach juice with different maturities were separated and identified by high-performance liquid chromatography (HPLC) and gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that sucrose and malate were the major accumulation forms in mature fruits. 70% maturity fruit juice had the lowest total sugar and total acid content. The total sugar (112.58 mg/g FW), sweetness value (99.40), sugar-acid ratio (15.57), and sweet-acid ratio (13.74) of the 80% maturity fruit juice were relatively high, and the sweet and sour flavor was strong. Meanwhile, the relative content of alcohol (11.79%) in 80% maturity fruit juice was higher, giving the juice a strong fruity and sweet aroma. The sweetness value (93.35), sugar-acid ratio (13.38), and sweet-acid ratio (11.93) of the 90% maturity fruit juice were the lowest. As the maturity increased, the ester content gradually increased, while the aldehyde content gradually decreased. The principal component analysis showed that 80% maturity fruit juice was suitable for processing high-quality honey peach juice, with a suitable sweet-sour taste, and strong fruity, floral aromas. This study provides theoretical and data support for the research and development of honey peach juice based on natural flavor.

In order to determine the effect of high pressure homogenization (HPH) on the stability and quality of not-from-concentrate (NFC) cloudy honey peach juice, the samples were subjected to HPH processing with 20~40 MPa for 1~2 successive passes. The changes in turbidity, centrifugation precipitating rate, particle size distribution, Zeta potential, water soluble pectin content, pectin methylesterase (PME) activity, pH, total soluble solids (TSS), total acidity (TA), TSS/TA, reducing sugar content, color, total phenol and VC content were evaluated. The results showed that HPH could effectively improve the stability of NFC cloudy honey peach juice. With the treatment of 30~40 MPa/1 and 20~40 MPa/2, the centrifugation precipitating rates significantly decreased by 13.49%~24.22% (P0.05). HPH decreased the pH, TSS, TA, total phenol and VC content with increasing pass number (P

In order to study the effect of high pressure processing on water bamboo (Zizania caduciflora L.) juice, this study compared the effects of high pressure processing (HPP, 400~500 MPa/5~10 min) and conventional heat treatment (TP, 80 ℃/10 min) on the physicochemical quality, nutritional components, antioxidant properties and volatile flavor components of non-concentrated reduced (NFC) water bamboo juice. The results showed that the sensory quality of heat-treated water bamboo juice was reduced and significant stratification occurred, while HPP treatment had no significant effect on pH, soluble solids and titratable acid content in water bamboo juice (P>0.05), and reduced stratification and improved the sensory quality of water bamboo juice. Meanwhile, compared with TP treatment, HPP treatment could better maintain the total phenols, flavonoids and DPPH free radical scavenging rate in water bamboo juice. In addition, gas chromatography-ion mobility chromatography (GC-IMS) flavor analysis showed that HPP increased the fruit and herbaceous aromas in water bamboo juice, which enhanced the flavor of water bamboo juice. In conclusion, compared with the traditional TP treatment, the HPP treatment had significant advantages in maintaining the quality characteristics, antioxidant and flavor of water bamboo juice.

The application of the cast WC, the Co powder coated cast WC and the Ni powder coated cast WC particles in diamond saw blades were studied, and their effects on the mechanical properties, the micro morphologies and the cutting properties of the diamond saw blade matrix were explored. The results show that when the mass ratio of the three kinds of WC material to the metal powder is 3∶1, the hardness of the three kinds of matrix is equivalent. The bending strength of the matrix containing Co powder coated cast WC is the highest, the interface between the WC particles and the matrix is the closest, and the microstructure of the matrix is the densest. The bending strength of the matrix containing Ni powder coated cast WC is the second. The matrix with only cast WC has the worst bending strength. Compared with the saw blade with only cast WC added, the cutting life of the saw blade with Co powder coated cast WC is the longest and increases by 40%.

In this paper, the “sonar percolation detection or logging” technology, which has emerged recently, is questioned from the aspects of test principle and calculation method, and the serious problems of this technology are pointed out. It is considered that sonar technology can not be used for seepage testing.