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Chip junction temperature is a key factor affecting the normal operation of the chip. The development of integrated circuit technology brings about high integration and low cost, but it also puts forward higher requirements for the cooling system. This paper focuses on the air cooling of the chip, builds a hardware test platform based on MCS-52, the general name of the intel series microcontroller unit, and sets up a mathematical model of the air cooling process of the chip on the MATLAB platform based on the principle of energy conservation, heat transfer theory and finite element method. By proposing the equivalent convective heat transfer coefficient, the thermal resistance of the system can be well estimated. This model can easily realize the joint simulation of chip, heat radiator and control strategy, which overcomes the disadvantage that traditional finite element simulation software are difficult to combine with control strategy. In addition, based on the model, the proportional integral differential (PID) control parameters are automatically optimized, achieving excellent temperature control effect, and proving the feasibility of optimizing the control parameters through the model.

Combining shape memory alloy (SMA) and carbon fiber-reinforced polymer (CFRP) sheet can achieve a self-stressing SMA-CFRP composite, providing an innovative prestressing method for steel elements. This study applied SMA(Ni–Ti–Nb) wires and CFRP sheets to achieve composite strengthening for notched steel beams. The effectiveness of SMA-CFRP composite for flexural strengthening of notched steel beams was evaluated, and the formula for the maximum allowable moment of the strengthened beams with SMA-CFRP composites was proposed. The four-point bending test results showed that the ultimate load and flexural stiffness of the strengthened beams with SMA-CFRP composites increased by 79.2% and 57.9% more than those of the unstrengthened beams. By comparison, the CFRP-only and SMA-only strengthened beams merely achieved half the ultimate load and flexural stiffness over the strengthened beams with SMA-CFRP composite. Besides, compared to the unstrengthened beams, the notch tip yield load for the strengthened beam with SMA-CFRP composite was increased by 230%, while the notch tip yield load for strengthened beams with CFRP-only and SMA-only just increased by 70% and 125%. These indicate that the SMA-CFRP composite strengthening can significantly delay crack propagation and improve the load capacity and stiffness of notched steel beams. Moreover, the analytical results of the maximum allowable moment were in good agreement with experimental results, indicating the accuracy of the proposed analytical equations.

Sorghum has a long history of cultivation and is an important food and economic crop. It can be divided into glutinous and non-glutinous varieties according to the starch structure and content. Rapid discrimination between the two would help the winemaking, feed, and food industries complete purchase pricing, ingredients, and quality control. In this study, 38 different samples were acquired, including 14 glutinous and 24 non-glutinous sorghum samples. Near infrared (NIR) spectra of glutinous and non-glutinous sorghum, pre-treated using the standard normal variable (SNV) transformation were found to have slightly different absorbances in the combination and first overtone bands. Based on the distribution of the starch-related and hydrogen-containing groups in the NIR region, it was concluded that glutinous sorghum has more C-O and C-C groups than non-glutinous sorghum. This study proposes an approach based on typical samples and direct calibration (TSDC) for binary discrimination. The TSDC approach consists of three functions. First, typical samples of two types of samples were selected. Second, typical type samples are used as dependent variables, predicted samples are used as independent variables, and formula regression is used to obtain fitted coefficients. Finally, if the formula regression model has no solution or the fitted coefficient is 1, typical type samples are reselected. Using the TSDC approach, discrimination accuracy can achieve 100% accuracy at 0.5 threshold. A larger threshold can be set to select better type characteristic predicted samples for discrimination. The TSDC approach can build excellent model through real relevance between the NIR spectra and the properties of interest, and the use of typical type samples greatly reduces modeling work compared with complex pattern recognition methods, especially for highly varied agricultural products. Therefore, it can efficiently propel the application and development of NIR detection technology. More research is required to apply the TSDC approach to three types of samples.

Study of life history strategies may help predict the performance of microorganisms in nature by organizing the complexity of microbial communities into groups of organisms with similar strategies. Here, we tested the extent that one common application of life history theory, the copiotroph-oligotroph framework, could predict the relative population growth rate of bacterial taxa in soils from four different ecosystems. We measured the change of in situ relative growth rate to added glucose and ammonium using both 18O–H2O and 13C quantitative stable isotope probing to test whether bacterial taxa sorted into copiotrophic and oligotrophic groups. We saw considerable overlap in nutrient responses across most bacteria regardless of phyla, with many taxa growing slowly and few taxa that grew quickly. To define plausible life history boundaries based on in situ relative growth rates, we applied Gaussian mixture models to organisms’ joint 18O–13C signatures and found that across experimental replicates, few taxa could consistently be assigned as copiotrophs, despite their potential for fast growth. When life history classifications were assigned based on average relative growth rate at varying taxonomic levels, finer resolutions (e.g., genus level) were significantly more effective in capturing changes in nutrient response than broad taxonomic resolution (e.g., phylum level). Our results demonstrate the difficulty in generalizing bacterial life history strategies to broad lineages, and even to single organisms across a range of soils and experimental conditions. We conclude that there is a continued need for the direct measurement of microbial communities in soil to advance ecologically realistic frameworks.