In order to improve the isolation effect of ultra-precision vibration isolation platform, an approach of advancing structural parameters optimization for the system based on fuzzy control is presented. This paper created a platform parametric model In ADAMS / view; completed the structural optimization under circumstances of taking the acceleration of vibration isolation platform, the system dynamic deflection and the dynamic displacement of the base as performance objective function; and applied the method of co-simulation using ADAMS and MATLAB under fuzzy control. The simulation results show that the active vibration isolation system optimized by ADAMS could effectively enhance the effect of active vibration isolation platform; the method of co-simulation provided a new way for dynamics studies of vibration isolation system.

As a preferred technology to enhance oilfield energy production, well stimulation has and will continue to have an important role in fulfilling the worlds future energy needs. Mud acid is a conventional acid system that reacts with most injurants and removes damages. However, fast reaction rate with minerals will lead to high leak-off velocity, great possibility of secondary and tertiary precipitation, lower effect of corrosion inhibitor in high temperature as well as short efficient operating range. Therefore, new kinds of acid system are required to cope with these problems above. This paper proposed three acid system with the similarity of fluorine ammonium compounds for sandstone acidizing ammonium hydrogen fluoride (AHF), ammonium fluotitanate (AFT), and ammonium fluoroborate system (AFB). Chemical structures, acidity test and solubility tests have proved the feasibility. Then, performance comparisons are conducted to prove the advantages over mud acid system.

Source of materialAmixture of N -benzyl-purin-6-amine (0.3 mmol), H 3 PMo 12 O 40 (0.1 mmol) and H 2 O(7mL) was sealed in a15mLTeflon-lined stainless steel autoclave and heated at 120°Cfor 2days. After the mixture was slowly cooled to room temperature, brown crystals were isolated by filtration and washed with distilled water (yield ca. 90 %based on Mo). DiscussionThe title crystal structure consists of aK eggin heteropolyoxometalate, [PMo 12 O 40 ] 3− anion, three protonated N-benzyl-purin-6-amine cations and five lattice water molecules. In the wellknown Keggin group, there are 12 MoO 6 octahedra and one PO4 tetrahedron. The octahedra are arranged in four groups of three edge-shared ones Mo 3 O 16 ,which are joined to each other by sharing corners. The PO 4 tetrahedron is located in the centre of the polyoxo anion by sharing its Oa toms with the four Mo 3O16 groups. The P-Odistances are in the range of 1.524 (5) . There is extensive intermolecular hydrogen bonding in the compound, via which adjacent moieties in the structure are connected, and a4-membered linear water cluster (O41, O42, O43 and O44) is formed, thus stabilizing the three-dimensional network.