Shock wave driven out by a piston in a mixture of a non-ideal gas and small solid particles under the influence of the gravitation field with monochromatic radiation

Similarity solutions for a spherical shock wave in a mixture of small solid particles of micro size and a non-ideal gas are discussed under the influence of the gravitational field with monochromatic radiation. The solid particles are uniformly distributed in the mixture, and the shock wave is assumed to be driven by a piston. It is assumed that the equilibrium flow-conditions are maintained and the moving piston continuously supplies the variable energy input. Due to the central mass ($\overline{m}$) at the origin (Roche model), the medium is considered to be under the influence of the gravitational field. In comparison to the attraction of the central mass at the origin, the gravitational effect of the mixture itself is neglected. The density of the undisturbed medium is assumed to be constant in order to obtain the self-similar solutions. The effect of the parameter of non-idealness of the gas $\overline{b}$, the mass concentration of solid particles in the mixture μ_p, the ratio of the density of solid particles to the initial density of the gas G_a and the gravitational parameter G₀ are obtained. It is shown that due to an increase in the gravitational parameter the compressibility of the medium at any point in the flow field behind the shock front decrease and the flow variables velocity, pressure, radiation flux and shock strength are increased. Also, an increase in the ratio of the density of solid particles to the initial density of the gas G_a and the gravitational parameter G₀ has the same effect on the shock strength and the reverse effect on the compressibility. The non-idealness of the gas causes a decrease in the shock strength and widens the disturbed region between the piston and the shock.     

救生潜艇对接时冲击过程的分析

本文分析了救生潜艇在对接时的冲击过程.文中给出了计算液压缓冲器的变形和艇的冲击加速度的方法.计算中考虑了液压缸的非线性特性和大变形引起的几何非线性.     

瓦斯爆炸对巷道壁面损伤破坏的数值模拟研究

为了研究巷道内瓦斯爆炸冲击波对巷道壁面结构的损伤破坏,利用ANSYS/LS-DYNA建立巷道瓦斯爆炸物理模型和数学模型,对掘进巷道瓦斯爆炸冲击波破坏特性进行数值模拟研究。结果表明:在巷道壁面边缘位置和中心位置超压测值较大,其壁面损伤相对更为严重;冲击波在巷道轴向壁面也会出现反射和叠加,导致整体超压峰值上下振荡波动;瓦斯爆炸后冲击波向开口方向传播,瓦斯区壁面受到的载荷最大,并逐渐向空气区加载扩散;随着爆炸冲击波能量衰减,而应力持续加载在壁面结构,压力集中对壁面结构施加静态破坏,最后超过其承受能力,导致巷道失稳破坏。研究结果可为优化巷道结构的设计提供理论参考。     

双筒液压减振器异响的计算机仿真研究

利用基于Bouc-wen滞回环的非线性减振器模型对减振器进行计算机仿真分析,发现减振器可变阻尼力的减小是减振器异响产生的原因,同时给出了避免可变阻尼力减小的方法.     

稠密氦气物态方程研究

用二级氢气炮作为冲击压缩加载工具和多通道瞬态辐射高温计作为主要测量系统,测量了冲击压缩氦气等离子体的光辐亮度历史（初始温度293K,初始压力为1.2MPa）。根据实测记录信号波形的有关特征量,计算得到了氦等离子体的Hugoniot物态方程（含冲击温度）。结果发现：实测Hugoniot物态方程可用Saha方程加Debye-Huckel修正物理模型解释。     

Shock Formation for 2D Isentropic Euler Equations with Self-similar Variables

The author studies the 2D isentropic Euler equations with the ideal gas law. He exhibits a set of smooth initial data that give rise to shock formation at a single point near the planar symmetry. These solutions to the 2D isentropic Euler equations are associated with non-zero vorticity at the shock and have uniform-in-time 1 3-H¨older bound. Moreover, these point shocks are of self-similar type and share the same profile, which is a solution to the 2D self-similar Burgers equation. The proof of the solutions, following the 3D construction of Buckmaster, Shkoller and Vicol (in 2023), is based on the stable 2D self-similar Burgers profile and the modulation method.     

Recent studies on advance spectroscopic techniques for the identification of microorganisms: A review

The continuous development of resistance to antibiotic drugs by microorganisms causes high mortality and morbidity. Pathogens with distinct features and biochemical abilities make them destructive to human health. Therefore, early identification of the pathogen is of substantial importance for quick ailments and healthcare outcomes. Several phenotype methods are used for the identification and resistance determination but most of the conventional procedures are time-consuming, costly, and give qualitative results. Recently, great focus has been made on the utilization of advanced techniques for microbial identification. This review is focused on the research studies performed in the last five years for the identification of microorganisms particularly, bacteria using advanced spectroscopic techniques including mass spectrometry (MS), infrared (IR) spectroscopy, Raman spectroscopy (RS), and nuclear magnetic resonance (NMR) spectroscopy. Among all the techniques, MS techniques, particularly MALDI-TOF/MS have been widely utilized for microbial identification. A total of 44 bacteria i.e., 6 Staphylococcus spp., 3 Enterococcus spp., 6 Bacillus spp., 4 Streptococcus spp., 6 Salmonella spp., and one from each genus including Escherichia, Acinetobacter, Pseudomonas, Proteus, Clostridioides, Candida, Brucella, Burkholderia, Francisella, Yersinia, Moraxella, Vibrio, Shigella, Serratia, Citrobacter, and Haemophilus (spp.) were discussed in the review for their identification using the above-mentioned techniques. Among all the identified microorganisms, 21% of studies have been conducted for the identification of E. coli, 14% for S. aureus followed by 37% for other microorganisms.