A combined immersed boundary–lattice Boltzmann approach is used to simulate the dynamics of the fluid–structure interaction of a hollow sealing strip under the action of pressure difference. Firstly, the multiple relaxation times LBM model, hyper-elastic material model and immersed boundary method were deduced. According to the strain characteristics of hyper-elastic materials and the specific situation of friction between the elastic boundary and solid boundary, the internal force and the external force on the immersed boundary were discussed and deduced, respectively. Then, a 2D calculation model of the actual hollow sealing strip system was established, during which technical problems such as the equivalent wall thickness of the sealing strip and the correction of the stiffness of the contact corner were solved. The reliability of the model was verified by comparing results of FEM simulation of quasi-static deformation. Following this, the simulation results of three typical cases of sealing strips were presented. The results show that when the sealing strip fails, there will be a strong coupling phenomenon between the flow field and the sealing strip, resulting in the oscillation of the flow field and the sealing strip at the same frequency.

To evaluating and measure the security of an enterprise or a public network is an important step for the security of network itself and defence outside threat. So many of the current research in cyber analysis were focusing on it. In the field of network security, others have used CVSS, security metrics and attack graph to evaluate software systems or automation systems. However, no article has used these methods to study the SME(small and medium-sized enterprises) network, and there is no complete set of methods to evaluate the topology of the SME network, as well as which security metrics to use to evaluate the network and which metrics are the most important, there is no conclusion at present. Therefore, this paper will use the research results mentioned above to focus on solving this problem. In this paper, first of all, we tried different network constructing technique, and used attack graph to generate the absorbing Markov chain model, then calculated the security metrics base on CVSS. Finally, we analyzed the meaning of different metrics and the score of each of them and gave the suggestion for improvement for this network. Finally, we found that when faced with the network topology of small and medium-sized enterprises, the various metrics are only relatively important, and there are no completely unimportant metrics. Therefore, security engineers need to model the topology structure of the network and use tools to generate the attack graph, calculate the security metrics and make adjustments when building the network. Security engineers need to comprehensively consider various metrics to adjust and analyse the network to determine the security of the network, instead of adjusting the network after it's built.

To reduce the cost of high-viscosity modifier (HVM) and alleviate white pollution problems, we prepared the environment-friendly HVM (E-HVM) by using waste-low density polyethylene/styrene-butadiene-styrene (waste-LDPE/SBS) composite. The physical characteristics of the E-HVM modifier were first investigated. Additionally, the effects of E-HVM modifier dosage (8 wt% to 20 wt%) on the rheological properties and microstructure of asphalt were, respectively, researched by dynamic shear rheometer (DSR), bending beam rheometer (BBR), and fluorescence microscopy (FM). The results show that the E-HVM modifier has lower molecular weight, and its distribution is wider than that of the Tafpack-Super (TPS) modifier; thus, the E-HVM modifier had better compatibility with asphalt, which has also been proven by FM images. Due to these reasons, the E-HVM modifier improves the high-temperature performances of asphalt more effectively than the TPS modifier, which is shown by the higher dynamic viscosity (60 °C) and G* and the lower and Jnr (τ). Furthermore, compared to TPS modified asphalt, E-HVM modified asphalt also has a higher fatigue life at different strain levels (2.5% and 5.0%), but worse low-temperature performance. Following a comprehensive consideration of performances, the reasonable dosage range of E-HVM modifier is 12 wt% to 16 wt%.

Immersed boundary-lattice Boltzmann method was used to study the failure of automobile door sealing strip considering fluid-structure interaction under pressure difference. Based on the actual vehicle model, a two-dimensional calculation model of simplified automobile door sealing strip was established by using immersed boundary method, and practical problems such as the equivalent sealing strip wall thickness correction, wall friction, and pressure balance holes were solved. The accuracy of the model was verified by finite element method. The unsteady pressure outside the vehicle was obtained by CFD and verified by wind tunnel experiment, which could be used as references for setting boundary conditions. In the process of studying the seal failure, by setting the average value, the fluctuation amplitude and the frequency of pressure difference, an automatic iterative program was compiled to obtain the failure situations of the seal under critical pressure difference conditions. The results show that the constant value of the unsteady pressure outside vehicle is the dominant factor, then the coupling between the unsteady pressure frequency and the sealing strip natural frequency, or the increase of the fluctuation range will aggravate seal failure.

Double Reduction Policy has strongly affected the education industry in China, especially to those mainly rely on the revenue coming from K-12 education. Since the policy prohibits education organizations gaining revenue from academic tutoring including K-12 education. Thus, many education giant companies bankrupted while New Oriental re-emerged through this crisis. The reason behind this phenomenon is worth exploring. Therefore, this study will investigate the case of New Oriental to analyze how they catch up the opportunity in this crisis. This article will mainly focus on two parts that the success of its business restructuring and its attempt to enter the live-streaming selling market. Specifically, Quantitative Analysis is presented to compare the financial data before and after business restructuring. EFE and IFE matrix method are adopted to analyze the external and internal environment of New Oriental. In addition, SWOT analysis is used to weigh the pros and cons of entering the live-streaming selling markets. According to the analysis, threat and opportunity coexist and New oriental make full use of its strengths to re-emerge under Double Reduction Policy. The basic strategy is following the relevant national policies. In addition, this paper also provides some investment suggestions for those are still struggling to survive from the change. These results shed light on research the impact of national policy to the educational industry.