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Objective: The objective of this study was to investigate the effects of wilting and additives on the fermentation quality, structural and non-structural carbohydrate composition of mulberry silages. Methods: The selected lactic acid bacteria strains Lactobacillus plantarum 'LC279063' (L1), commercial inoculant Gaofuji (GF), and Trichoderma viride cellulase (CE) were used as additives for silage preparation. Silage treatments were designed as control (CK), L1, GF, or CE under three wilting rates, that is wilting for 0, 2, or 4 hours (h). After ensiling for 30 days, the silages were analyzed for the chemical and fermentation characteristics. Results: The results showed that wilting had superior effects on increasing the non-structural carbohydrate concentration and degrading the structural carbohydrate. After ensiling for 30 days, L1 generally had a higher fermentation quality than other treatments, indicated by the lower pH value, acetic acid, propionic acid and ammonia nitrogen (NH 3 -N) content, and the higher lactic acid, water soluble carbohydrate, glucose, galactose, sucrose, and cellobiose concentration (p<0.05) at any wilting rate. Wilting could increase the ratio of lactic acid/acetic acid and decrease the content of NH 3 -N. Conclusion: The results confirmed that wilting degraded the structural carbohydrate and increased the non-structural carbohydrate; and L1 exhibited better properties in improving fermentation quality and maintaining a high non-structural carbohydrates composition compared with the other treatments.

A new particle swarm optimization based on dynamic parameter modification is proposed in this paper (Dynamic Parameter Modification Particle Swarm Optimizer, DPSO). In DPSO algorithm , is doing oscillating decay breaking through the constraint of topical linear decreasing, and the Euclidean distance and is calculated, which respectively stand for the Euclidean distances form the position of particle to the best position that the particle has passed and the best position that all the particles have passed under the time . Parameters and of topical PSO are modified dynamically based on the comparison of and in order to coordinate between global search and local search. Then find out the optimal value of Goldstein-Price function using topical PSO and the improved DPSO respectively, and the results demonstrate that compared to topical PSO, DPSO algorithm avoids falling into the local minimum and improves the search efficiency.

With the development of automotive industry of China, more and more new cars are brought out. Then more and more stylists and engineers will take part in car styling to design new car. In the process of car styling, Car aerodynamics is important to its performance. Especially for more excellent handling and stability performance, more aerodynamic analysis and optimization should been done. At first it was introduced that the process of car styling in this paper. The functions of aerodynamics in the process were indicated. Secondly some ways of aerodynamic analysis were put forward. The first one is wind tunnel test and the second one called virtual wind tunnel test. The virtual wind tunnel test is one of the best modern ways of aerodynamic design which apply in the fields of aerodynamic research widely. It was based on computational fluid dynamics. The details of the virtual wind tunnel test simulation were narrated in this paper. Applying the virtual wind tunnel test aerodynamic drag coefficient, velocity contour and pressure distribution were got. Some advices to reduce aerodynamic drag of the design car were put forward. In one word, it is one simple, effective, convenient and fast way for aerodynamic design in car styling process using virtual wind tunnel test.

With the rapid development of FSAE, the speed of racing cars has increased year by year. As the main research content of racing cars, aerodynamics has received extensive attention from foreign teams. For racing cars, the aerodynamic force on the aerodynamic device ultimately acts on the tires through the transmission of the body and the suspension. When the wheel is subjected to the vertical load generated by the aerodynamic device, the ultimate adhesion capacity of the wheel is improved. Under changing conditions, racing wheels can withstand greater lateral and tangential forces. Therefore, the effects of aerodynamics have a more significant impact on handling stability. The FSAE racing car of Jilin University was taken as the research object, and this paper combines the wind tunnel test, the numerical simulation and the dynamics simulation of the racing system. The closed-loop design process of the aerodynamics of the FSAE racing car was established, and the joint study of aerodynamic characteristics and handling stability of racing car under different body attitudes was realized. Meanwhile, the FSAE car was made the modification of aerodynamic parameter on the basis of handling stability. The results show that, after the modification of the aerodynamic parameters, the critical speed of the car when cornering is increased, the maneuverability of the car is improved, the horoscope test time is reduced by 0.525 s, the downforce of the car is increased by 11.39%, the drag is reduced by 2.85% and the lift-to-drag ratio is increased by 14.70%. Moreover, the pitching moment is reduced by 82.34%, and the aerodynamic characteristics and aerodynamic efficiency of the racing car are obviously improved. On the basis of not changing the shape of the body and the aerodynamic kit, the car is put forward to shorten the running time of the car and improve the comprehensive performance of the car, so as to improve the performance of the car in the race.

With the development of automotive technology and high-speed highway construction, the speed of the vehicles increase which cause the significant increase in the aerodynamic drag when road vehicles are moving. Thereby the power of the vehicles, fuel economy, operational stability and other properties are affected very seriously. Heavy-duty commercial vehicles as the most efficient way to transport goods on the highway are widely used, and the speed of the vehicles increases faster. Especially the demands for heavy-duty commercial vehicles are increasing in recent years. Reducing the aerodynamic drag by the analysis of external aerodynamic characteristics, improving the fuel economy and reducing energy consumption have become new research topics of heavy-duty commercial vehicles. To make the heavy-duty commercial vehicles meet the national standards of energy saving, a simplified heavy-duty commercial truck model was built in this paper. The numerical simulation of the vehicle was completed based on the theory of the aerodynamics. The aerodynamic characteristics were analyzed, according to the graphs of the pressure distribution, velocity distribution and flow visualization. To improve the aerodynamic characteristics of heavy-duty commercial vehicles, the main drag reduction measures are reducing the vortex of the cab and the container, the end of the container and the bottom of the container.

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Ni-Fe layered double hydroxide containing carbonate anion (CO32- ) has been successfully synthesized by a process of homogeneous precipitation involving urea hydrolysis under hydrothermal conditions. Factors that influence the composition and the crystallinity degree of NiFe-LDH, such as the molar fraction of urea/NO3- in solution, the total metal ion concentration in solution and the aging time, have been investigated in detail. Structure and morphology of the sample were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectra and scanning electron microscope (SEM). The results indicate NiFe-LDH with high purity present well-crystalline, uniform crystallite size