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In the present study,the modified magnesium hydroxide was prepared by precipitation method using Mg(NO3), NaOH, and silane coupling 702 modifier as raw materials. The optimal reaction conditions were obtained as follows: sodium hydroxide was added to magnesium nitrate solution by dropping, the dropping speed of sodium hydroxide was 2ml/min, the reaction temperature was 60℃, and the ratio of modifier dosage to total solution volume was 7/100(g/ml). The oil absorption value and XRD were used to characterize the modified Mg(OH)2. In the application, the modified magnesium hydroxide was mixed with pentaerythritol octahydrogen tetraphosphate(PEPA) and applied to nylon 66(PA66).The flame retardancy and mechanical properties of the nylon 66(PA66)composite were studied.

Ethyl cyanoacetate is an important chemical intermediate and has been used widely. Ethyl cyanoacetate was prepared by esterification of cyanoacetic acid and absolute ethanol with mixed catalyst (the same proportion of silicotungstic and p-toluene sulfonic acid as catalyst). The influence factors of the amount of catalyst, n(cyanoacetic acid): n ( absolute ethanol), reaction time and reaction temperature on the esterification rate was investigated by orthogonal experiment of four factors and three levels. The product was analyzed by gas chromatography to determine the optimum reaction conditions.

Aircrafts maintenance, temporary airport closures are common factors that disrupt normal flight schedule. The aircraft route recovery aims to recover original schedules by some strategies, including flights swaps, and cancellations, which is a NP-hard problem. This paper proposes an improved heuristic procedure based on Greedy Random Adaptive Search Procedure (GRASP) to solve this problem. The effectiveness and high global optimization capability of the heuristic is illustrated through experiments based on large-scale problems. Compared to the original one, it is shown that the improved procedure can find feasible flight recovered schedules with lower cost in a short time.

A kind of UAV electric servo detection system based on Virtual Instrument is designed in this paper, including the hardware platform based on PC-DAQ virtual instrument architecture and the software platform based on LabVIEW function, structure and system implementation methods. The function, structure and system implementation method of software platform is also described. The gear limits checking, zero testing, time domain characteristics test results showed that the system achieves testing requirements well, and can complete detection of electric steering gear automatically, fast, easy and accurate.

The blank size, determining the deformation degree and the ratio of axial to radial feed amount of the radial-axial ring rolling process for TA15 titanium alloy, has a strong effect on the grain size and volume fraction of primary α phase, which determine the mechanical properties of the rolled ring. In this paper, a macro-micro 3D-FE model of the radial-axial ring rolling of TA15 titanium alloy has been developed under ABAQUS software. The ring blank transferring from heating furnace to rolling mill, rolling and cooling after rolling during the whole process are considered in the FE model. And multiple blanks with different rolling ratios and ratios of axial to radial feed amount are designed for a desired TA15 titanium alloy ring. Then, the effects of the blank size on the grain size and volume fraction of primary α phase in the rolled ring are investigated by comprehensive FE simulations. Finally, the optimum blank sizes are obtained by evaluating both the volume fraction of primary α phase and the distribution uniformities of grain size and volume fraction of primary α phase.

In this work, an analytical study of the macroscopic deformation and microstructure evolution of Ti-6Al-2Zr-1Mo-1V alloys during rolling-spinning forming process was performed by developing Finite Element (FE) modeling using the ABAQUS/Explicit platform. The developed FE model was validated by comparing with experimental results. To investigate the shearing deformation during rolling-spinning process, representative nodes were selected in the FE model. The shearing strains of these nodes were obtained by modeling. The influence of shearing deformation in rolling-spinning forming process on microstructures was also analyzed. An optimal selection of process parameters was obtained to achieve better microstructure.

Modeling sheet metal forming operations requires understanding of plastic behaviors of sheet metals along non-proportional strain paths. The plastic behavior under reversed uniaxial loading is of particular interest because of its simplicity of interpretation and its application to material elements drawn over a die radius and underwent repeated bending. However, the attainable strain is limited by failures, such as buckling and in-plane deformation, dependent on clearances and side forces. In this study, a finite element (FE) model was established for the compression process of sheet specimens, to probe the deformation behavior. The results show that: With the decrease of the clearance from a very large value to a very small value, four defects modes, including plastic t-buckling, micro-bending, w-buckling, and in-plane compression deformation will occur. With the increase of the side force from a very small value to a very large value, plastic t-buckling, w-buckling, uniform deformation, and in-plane compression will occur. The difference in deformation behaviors under these two parameters indicates that the successful compression process without failures for sheet specimens only can be carried out under a reasonable side force.