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To adapt to the complex and changing environment, the artillery often needs to be launched at different ambient temperatures, and different temperatures can have complex effects on the muzzle flow characteristics. It is crucial to fully understand the effect of ambient temperature on the muzzle flow field characteristics, which will help optimize the design of the propellant charge and improve the stability and consistency of the ballistic trajectory. Therefore, the internal and intermediate ballistic trajectories of the artillery are simulated to investigate the effect of ambient temperature on muzzle flow development and the phenomenon of secondary combustion. A set of internal ballistic equations is used to provide precise velocity and pressure as the projectile moves to the muzzle. By coupling the van der Waals gas state equation and a detailed chemical reaction kinetic model, the multispecies Navier–Stokes equations with complex chemical reactions were solved. The established numerical model is validated by comparing it with experimental results. The results demonstrate that the shock wave propagation speed gradually increases and the shock wave intensity gradually decreases with the increase in ambient temperature. The initial formation time of Mach disk lags, and the diameter of the Mach disk decreases with increasing temperature, while the displacement of the Mach disk increases with increasing temperature. The structure of muzzle flash is synchronized with the Mach disk structure; the lower the temperature, the "shorter and fatter" the flash is. [ABSTRACT FROM AUTHOR]

The mountain area is faced with complex coJdjtions sucn as vertical and horizontal valleys, complex geologd topography, Vmny earthquake fault zones, high seismic intensityfriBk ecologyBkcriangeable climate. The traditional concrete bridgee heavy weilrhigh consumption of sand and gravel materials, large structural dimensions of steel box composite bridges, high steel consumption, and poor overall horizontal performance of steel plate composite beams, which are not suitable for mountain construction conditions. Thejefore, based onthe construction environment and application requirements of highway bridges in mountainous areas, the structural scheme of steeHX-steel pete composite beam is put forward in this paper, and the design 50 m landaTa-span steel box-steel plate composite beam is studied. Jrfl®iesu[ts show that the steel box-steel plate composite beam structure scheme is adopted, which has excellent mechanical characteristics of steel box girder and k simple structure of steel plate girder. It has the mechanical characteristics of balancidtransverse force and excellent longitudinal force", so it is a reasonable choice for small radius curved beam bridge in a mountainous area, so it is a reasonable choice for small radius curved beam bridge in a mountainous area. The steel box-steel plate composite beam adopts the integrated technology of manufacture, transportation and installation, which can better meet the road transport conditions in the mountain area. The longitudinal assembly of the manufacturing unit as the installation unit can ensure the rapid and high-precision installation of the construction site, and the assembly construction of the bridge in the mountain area has been realized. The technical and economic comparison shows that the mechanical performance of steel box-steel plate composite beam is similar to that of steel box beam and obviously better than that of steel plate girder. The steel consumption and construction period of steel box- steel plate composite beam are similar to that of steel plate girder, and are significantly less than that of the steel box girder. Therefore, the steel box- steel plate composite beam is a good choice for mountain bridge construction. [ABSTRACT FROM AUTHOR]

Inner Mongolia traditional dairy products are high quality medium for lactic acid bacteria. In order to preserve lactic acid bacteria resources in camel dairy products in Alxa region of Inner Mongolia and study the microbial diversity, the pure culture method and metagomic sequencing technology were respectively used to evaluate and preserve. Metage-nomic results showed that the microbial diversity of fresh camel milk was significantly higher than that of sour camel milk, and 157 species were identified from 18 samples. Lactococcus lactis (13.22% ) and Acinetobacter guillouiae (10.65%) were the dominant species. The dominant species were Lactobacillus helveticus (72.66%), Lactobacillus kefi-ranofaciens (8.32%) and Lactococcus lactis (4.28%). A total of 121 strains of Lactobacillus were further isolated from the samples by pure culture and identified as 14 species of 4 genera, in which the dominant specie of fresh camel milk is Lactococcus lactis (62.00%). The dominant species were the Lactobacillus helveticus (40.00%) and the Lactobacillus ke-firanofaciens (19.00%), which were consistent with the metapomic results. The combination of metagomic sequencing and pure culture method effectively realized the microbial diversity analysis and Lactobacillus resource mining of camel milk samples, providing a theoretical basis for the industrial production of camel milk and the utilization of lactobacillus resources. [ABSTRACT FROM AUTHOR]

A series of comb polymers poly(2-(dimethylamino)ethyl methacrylate (DMAEMA)-co-methacrylic acid (MAA)-co-methoxy polyethylene glycol methacrylate (MPEGMA)) (poly(DMAEMA-MAA-MPEGMA, DMM) were synthesized and used as N-methyl-2-pyrolidinone (NMP)-based lithium iron phosphate (LFP) suspension dispersants. The effects of the grafting density of the carboxyl group as the anchoring group and the chain length of the side chain of PEG, which plays the role of spatial site resistance, on the rheological properties and suspension stability of the slurry were systematically investigated. By investigating the adsorption amount and thickness of DMM on the LFP surface, combined with calculations based on the scalar law and Flory theory, the molecular structure of the comb polymer dispersant was revealed to influence the adsorption and dispersion performance. The dispersion of LiFePO4 was due to the synergistic effects of adsorption and steric hindrance effect, which resulted that dispersants with medium carboxyl density and PEG side chain length can improve the dispersion performance and stability. [ABSTRACT FROM AUTHOR]

The Modular and Integrated Data Assimilation System (MIDAS) software (version 3.9.1) is described in terms of its range of functionality, modular software design, parallelization strategy, and current uses within real-time operational and experimental systems. MIDAS is developed at Environment and Climate Change Canada for both operational and research applications, including all atmospheric data assimilation (DA) elements of the numerical weather prediction systems. The software is designed to be sufficiently general to enable other DA applications, including atmospheric constituents (e.g. ozone), sea ice, and sea surface temperature. In addition to describing the current MIDAS applications, a sample of the results from these systems is presented to demonstrate their performance in comparison with either systems from before the switch to using MIDAS software or similar systems at other NWP centres. The modular software design also allows the code that implements high-level components (e.g. observation operators, error covariance matrices, state vectors) to easily be used in many different ways depending on the application, such as for both variational and ensemble DA algorithms; for estimating the observation impact on short-term forecasts; and for performing various observation pre-processing procedures. The use of a single common DA software for multiple components of the Earth system provides both practical and scientific benefits, including the facilitation of future research on DA approaches that explicitly include the coupled connections between multiple Earth system components. To this end, work is currently underway to allow the use of MIDAS DA algorithms for initializing both deterministic and ensemble three-dimensional ocean model forecasts. [ABSTRACT FROM AUTHOR]

Most annual studies of tintinnid and phytoplankton in coastal habitats are influenced by alien species introduced by water masses exchange, and therefore cannot be used as direct evidence for exploring the mechanism of annual succession in indigenous community. For brackish communities, very limited annual studies exist because of the difficulty of conducting stable sampling in the transition between freshwater and seawater. The special topography of Xiangshan Bay isolates the external water mass and provides a suitable habitat for exploring the annual succession mechanism of the brackish tintinnid community. In this study, samples were collected from seven stations in Tie Harbor, Xiangshan Bay (East China Sea) during 10 months from 2022 to 2023. A total of 23 tintinnid species of five genera were identified throughout the year. These tintinnid species can be clustered into four seasonal groups, winter, summer, autumn and spring-autumn, with three temperature preferences. The Lorica Oral Diameter (LOD) size-class of each tintinnid species, which determines the food item size of tintinnid, separated their different ecological niches within each seasonal group. The seasonal succession of tintinnid community in Xiangshan Bay was organized by both temperature preference and LOD size of the tintinnid species. [ABSTRACT FROM AUTHOR]