Search Results

You are looking at 1 - 7 of 7 items

  • Author: Jiao Ji x
Clear All Modify Search

Abstract

Magnesium hydroxide [Mg(OH)2] with high flame retardant efficiency filled polypropylene (PP) composites were prepared using a twin-screw extruder. The impact fracture behavior of the composites was measured at room temperature. It was found that the toughening effect of the filler content on the PP resin was significant. The V-notched Izod impact strength of the PP/Mg(OH)2 composites showed a nonlinear increase with increase in filler weight fraction (ϕ f), as ϕ f was <15%, and then it decreased slightly; When ϕ f was <15%, the V-notched Charpy impact strength of the PP/Mg(OH)2 composite also increased nonlinearly, then it decreased slightly. The impact fracture surface was observed by means of a scanning electronic microscope, to understand the toughening mechanisms for the composite systems.

Abstract

Acrylonitrile-butadienestyrene (ABS)/poly(methylmethacrylate) (PMMA)/ethylene methacrylate (EMA) composites were prepared with different blending sequences. All ABS/PMMA/EMA copolymers were designed to achieve the same total chemical composition, in which ABS/PMMA was equal to 80/20 and EMA was fixed at 6 wt%. The effects of different blending sequences on the mechanical and optical properties of ABS/PMMA/EMA blends were investigated. Results indicated that the tensile strengths of ABS/PMMA/EMA blends with different blending sequences were slightly affected, whereas the Izod impact strength of blends significantly varied. The impact toughness of the blends, in which PMMA/EMA was initially blended and then combined with ABS, was approximately twice that of the other blends. This blending sequence also had surface glossiness that was superior to those of the other blends. Differential scanning calorimetry and scanning electron microscopy further revealed that blending sequence influenced the phase miscibility and dispersion of the blends, which led to different mechanical and optical properties.

Abstract

Treatment of cis-[RuCl2(phen)2]·2H2O (phen=1,- 10-phenanthroline) with 1-(2,6-diisopropylphenoxy)-4-phenylphthalazine (HL1) or 1-(2,6-dimethylphenoxy)-4-phenylphthalazine (HL2) in the presence of AgPF6 afforded two cyclometalated ruthenium(II) complexes, [Ru(κ 2-C,N-L1)(phen)2](PF6) (1) and [Ru(κ 2-C,N-L2)(phen)2](PF6) (2), respectively. The two complexes have been characterized by UV–vis and luminescence spectroscopy. The structure of 1·1.5H2O has been determined by single-crystal X-ray diffraction.

Abstract

Gas turbine engine gas path fault diagnosis is closely related technology that assists operators in managing the engine units. However, the performance gradual degradation is inevitable due to the usage, and it result in the model mismatch and then misdiagnosis by the popular model-based approach. In this paper, an on-line integrated architecture based on nonlinear model is developed for gas turbine engine anomaly detection and fault diagnosis over the course of the engine's life. These two engine models have different performance parameter update rate. One is the nonlinear real-time adaptive performance model with the spherical square-root unscented Kalman filter (SSR-UKF) producing performance estimates, and the other is a nonlinear baseline model for the measurement estimates. The fault detection and diagnosis logic is designed to discriminate sensor fault and component fault. This integration architecture is not only aware of long-term engine health degradation but also effective to detect gas path performance anomaly shifts while the engine continues to degrade. Compared to the existing architecture, the proposed approach has its benefit investigated in the experiment and analysis.

Abstract

Microscopic electron properties of α-hexahydro-1,3,5-trinitro-1,3,5-triazine (α-RDX) with different shock wave velocities have been investigated based on molecular dynamics together with multi-scale shock technique. The studied shock wave velocities are 8, 9 and 10 km ⋅ s−1. It has been said that the shock sensitivity and reaction initiation of explosives are closely relevant with their microscopic electron properties. The reactions, including the reaction products, which are counted from the trajectory during the simulations are analysed first. The results showed that the number of the products strictly rely on shock wave velocities. The reaction rates and decomposition rates are also studied, which showed the differences between the different shock velocities. The results of electron properties show that α-RDX is a wide-gap insulator in the ground state and the metallisation conditions of shocked RDX are determined, which are lower than under-static high pressure.

Abstract

Chinese biochemical engineering is committed to supporting the chemical and food industries, to advance science and technology frontiers, and to meet major demands of Chinese society and national economic development. This paper reviews the development of biochemical engineering, strategic deployment of these technologies by the government, industrial demand, research progress, and breakthroughs in key technologies in China. Furthermore, the outlook for future developments in biochemical engineering in China is also discussed.