Conjugated microporous polymers (CMPs) are attracting increasing attention in chemical sensing due to their extended π-conjugated framework, permanent microporous structure, and large specific surface area. However, the extremely poor solubility and processability of CMPs, as well as the serious fluorescence quenching caused by aggregation, restrict their practical applications. Herein, a high-luminescence CMP film is constructed based on a novel dendrimer (TPETCz) featured by its central tetraphenylethylene "core" with aggregation-induced emission effect and its highly electro-active "branches." High specific surface area CMP films for analyte diffusion are fabricated by a facile in situ electropolymerization method. These dendrimerbased CMP films exhibit superior sensitivity to volatile organic compounds (VOCs). More importantly, 18 types, the most types reported, of VOC vapors are precisely distinguished by the linear discriminant analysis by establishing a 2D fluorescence sensor array based on the CMP films and the dendrimer monomer films.

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In recent years, hydropneumatic suspension (HPS) has come into widespread use for improving the ride comfort and handling of mining dump trucks and off-road vehicles. Therefore, it is critical to improve the mathematical modeling accuracy to enhance the design and control efficiency and accuracy of HPS. This paper aims to propose a model for improving the modeling precision by considering the effect of different factors on HPS characteristics. A computational fluid dynamic (CFD) model of a HPS was developed, and the volume of fluid (VOF) method was used for the transient calculations in order to simulate the fluid dynamic characteristics and determine the damping and stiffness forces of HPS. The effect of temperature, oil viscosity, nitrogen dissolution rate, and suspension vibration speed on the nonlinear characteristics of HPS was investigated. A limited number of simulation sample points were designed based on the variation ranges of the above factors using the design of experiment (DOE) method. The corresponding damping and stiffness force of each sample point were calculated by CFD simulation. The obtained simulation data were utilized for the fitting of a Kriging model. The results demonstrated that the Kriging model can provide high accuracy, with a prediction error lower than 5%. The proposed modeling method of the HPS nonlinear characteristics is highly efficient, accurate, and faster than traditional methods.

Delay time is an important factor in the quality of bench blasting. The development and application of electronic detonators make it possible to control the timing of detonation by a highly precise delay time. It is an easily achievable way to seek a better blast fragmentation by controlling the delay time. In order to investigate the influence of delay time on rock fragmentation, eight experiments on bench blasting models with double holes were carried out. The average weight of 4.59 g of pentaerythritol tetranitrate (PETN) was charged into each blast hole with a diameter of 10 mm. Delay times between the double holes were set as: 13.69, 27.36, 54.72, 60, 90, 120, 180, and 339.6 µs. During blast loading, the breakage processes of specimens were captured in detail by high-speed cameras. Full-field strains on the bench slope were analyzed by the three-dimensional digital image correlation (3D-DIC) technique. After each experiment, the coarse fragments were backfilled into the post-blast specimen to observe and record the bench slope’s final breakage pattern. The experimental results showed that the fragmentation of the bench slope transformed from horizontal crack dominance to vertical crack dominance as the delay time increased. In addition, post-blast fragments were collected and sieved, including fine materials. In the premise of approximate excavation, the optimum delay time was 180 µs. Compared to short delay times such as 27.36 µs, x50 was improved by approximately 25% at the delay time of 180 µs. The results showed a significant difference and great improvement in fragmentation when the delay times were in the time range of no-shock-wave interaction compared to interactions. When determining the optimum delay time in multi-hole blasting, except for the stress wave interaction, factors such as crack propagation should also be considered. The results of experiments could contribute to references for relevant research.

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