The line-of-sight (LOS) stabilization control is required to isolate LOS from the movement and vibration of carrier and ensure pointing and tracking for target in electro-optical tracking system. In this paper, a fractional-order PI (FOPI) controller is applied in the design of stabilization loop of LOS stabilization system based on the analysis of the fractional calculus theory. This controller exhibits excellent performance even in presence of nonlinearity and uncertainty. Details of this controller along with the performance comparisons between FOPI and conventional integer-order PI (IOPI) are presented. Simulation results indicate that the FOPI controller can improve the carrier disturbance rejection performance of LOS stabilization system.
In this paper, polyethylenepolyamine and hexanedioic acid were used in the polycondensation reaction for Polyamide-Polyamsne, which is the intermediate product that synthesis of Polyamide-Polyamsne-Epichlorohydrin. The difference and contact between polyethylenepolyamine, diethylenetriamine (DETA) and triethylenetetramine (TAPA) in the polycondensation reaction were compared. The exploration of the polycondensation reaction was discussed. The reaction between polyethylenepolyamine and hexanedioic acid was similar to the reaction between hexanedioic acid and DETA to TAPA. The appropriate conditions of polycondensation reaction were as following: The molar ratio of polyethylene polyamine and hexanedioic acid was 1:1. The polyamide-polyamine were synthesized by keeping 130 ~ 1350C for the first 30min, then increasing to 1600C and keeping for 2h. The solid content was about 50 %. And through theoretical analysis of gel, the degree of polymerization of Polyamine polyamide intermediate increases with increase the degree of reaction.
Rare earth/calcium phosphate composite coatings were fabricated on the surface of Ti-6Al-4V
by micro-arc oxidation (MAO) technique. The wear properties and corrosion resistant of rare earth/
calcium phosphate composite coatings in the simulated body fluid (SBF) have been investigated and the
bioactivity of the composite coatings were evaluated. The results show that the friction coefficient of the
composite coatings in the SBF is only 0.15~0.18 and the anode polarization potential of the coating has
been obviously enhanced about 0.18V compared with that of coatings of calcium phosphate coatings. So
the composite coatings have excellent wear and corrosion resistant properties. XRD analysis indicates
that the composite coatings can induce hydroxyapatite to form on its surface after soaked in SBF for 9d,
which shows that the composite coatings own good bioactivity.
Most colleges and universities have built a database of student achievement, but only a simple query and statistical operations, while hiding behind the data in these achievements even more valuable information has not been excavated and use. To solve this problem, this paper proposes the use of data mining association mining method on student achievement dig deeper; get relevant information between different courses for school administrators in decision analysis, the teacher's lesson plans and student learning arrangements.
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