ABSTRACT:We synthesized an epoxy matrix composite adhesive containing aluminum nitride (AlN) powder, which was used for thermal interface materials (TIM) in high power devices. The experimental results revealed that adding AlN fillers into epoxy resin was an effective way to boost thermal conductivity and maintain electrical insulation. We also discovered a proper coupling agent that reduced the viscosity of the epoxy-AlN composite by AlN surface treatment and increased the solid loading to 60 vol %. For the TIM sample made with the composite adhesive, we obtained a thermal conductivity of 2.70 W/(m K), which was approximately 13 times larger than that of pure epoxy. The dielectric strength of the TIM was 10 to 11 kV/mm, which was large enough for applications in high power devices. Additionally, the thermal and insulating properties of the TIM did not degrade after thermal shock testing, indicating its reliability for use in power devices.

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As fresh agricultural products are perishable and vulnerable, reducing inventory cost is a strategic target for supply chain enterprises. How to design a reliable multi-echelon inventory control policy is still a great challenge. Therefore, the inventory cost of a three-level fresh agricultural products inventory system was firstly mathematically analyzed. Then, the simulation-based optimization model of the multi-echelon inventory system for fresh agricultural products was proposed by using the Flexsim simulation software and the improved particle swarm optimization algorithm. Finally, the multi-echelon inventory system is simulated based on a large number of survey data. Simulation results demonstrate that the proposed simulation-based optimization model of multi-echelon inventory system for fresh agricultural products can provide decision-making and technical support for the formulation of inventory control policy, and also it shows that the modeling of system simulation is an effective method to solve the problem of complex system.

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Time–temperature indicators (TTIs) can monitor the quality and safety of food. A new temperature–time point comparison method was proposed to match TTIs with food. This method omits the step of calculating activation energy (Ea). It only compares the difference between TTI response time and food shelf life to determine their matching degree. Taking gold nanoparticle‐based TTIs and muffins as experimental objects, the new and the traditional matching methods were used to match the absorbance of TTI and the peroxide value of muffins. The two results are not significantly different. TTIs with gelatin solution and gold precursor solution concentration of 150.00  and 2.05 mg/mL, respectively, can show the quality of muffins. TTIs changed from light yellow to pink and finally appeared deep purple. The deep purple represented spoilage and inedibility of muffins. Comparing Ea of food and that of TTIs can preliminarily evaluate their matching degree, improving the experiment efficiency. Hence, it is reasonable to use the traditional matching method in most cases, and use the new method only when Ea of food cannot be obtained. Practical Application The deterioration rate of food is usually calculated by developing kinetic models of characteristic quality parameters. When the reaction rate is unavailable or inaccurate, the activation energy of food cannot be obtained. In this case, it is impossible to match TTIs with food based on the traditional method. This research develops a new matching method and helps TTIs and food to be matched without considering activation energy. It will promote the application of TTIs in more products.

In this study, we performed electric pulse treatment (EPT) on the cold-rolled pure copper sheets. And the effects of the current density of EPT on the microstructure and mechanical properties of the cold-rolled pure copper sheets were investigated. It has been found that the change in the current density of EPT has a remarkable influence on the surface temperature, microstructure, strength, plasticity and microhardness of the samples. Compared with the untreated sample, the elongation after fracture increased by about 3.2 times at a current density of 200A/mm2, whereas the ultimate tensile strength decreased by only 38.0%. Microstructures indicate that the electric pulse can induce rapid recrystallization in cold-rolled pure copper sheets within a short time, while reducing the dislocation density, weakening the rolling textures and increasing microstructure uniformity, thereby improving the plasticity of the material. Therefore, the present research has the potential to provide an effective alternative way to the traditional heat treatment of copper sheets and strips.