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In order to estimate and optimize the static and dynamic characteristics of machine tool, the full parameterized FEM model of it is established and studied in the paper. After the FEM analysis of bed, this paper takes a machine bed as example, presents a method of combination of BP Neural-Network(NN) and Genetic-Algorithm(GA) to optimize dynamic characteristics and realizes the structural optimization of the bed. It proved that this method takes less time, and more precision compared to traditional method.

In order to reduce the concentration of explosive gas, experimental research was carried out on the high pressure secondary rotating water jet ventilation characteristic, and the principle of high pressure secondary rotating water jet ventilation was analyzed. Experiments of the relationship between pressure and the suction air flow characteristics were carried out with different structure of jet pipe, different structure of nozzles, different throat in high pressure single rotating water jet ventilation, and the secondary rotating ventilation characteristic were tested with different guide vane angle. The results show that the air-sucking quantity approximatively increased with water pressure in accordance with parabola in the high press secondary rotating water jet ventilator, the air-sucking quantity of different structure of jet pipe was not same, the air-sucking quantity was significantly greater than that of swirl nozzle, the secondary rotary ventilation acts on the larger range.

In order to improve the cooling effect and practical applicability of falling temperature technique on high-temperature workplaces, the aeration and cooling principle of the high pressure water rotational jetting ventilation were analysed, and the experimental study was carried out. The results show that water pressure and cooling rate are an approximation of parabolic growth relationship, different structure of jet tube and temperature difference on water and gas also have an obvious effect on the cooling amplitude and air quantity. the guide vanes installed may improve effect of ventilation and cooling the capacity on high pressure water rotational jetting.

Boundary separation Approaching Rapid Casting is present. In this method, the 3-D CAD model of casting mould is sliced with certain thickness, and the 2-D profile of every slice is converted into the NC code automatically by computer. For case study, taking coated sand as material, casting moulds of propeller was made rapidly by self-developed laser rapid prototyping system. The casting test showed that this method can produce good quality parts. Boundary separation Approaching Rapid Casting with the characteristics of high production efficiency can cast products with complex cured surfaces in multi-variety and small batch, and it is a great significance in reducing the cost and shortening the cycle of new products development.

A series of phosphors with the composition of Y2.95-xCaxAl5-xSixO12: Ce3+0.05 (x=0, 0.15, 0.30, 0.45, 0.60, 0.75) were synthesized with conventional solid state reactions. The results of XRD patterns show that in a certain extent, the co-substitution of Ca2+ and Si4+ does not change the garnet structure of samples, while results in the shrink of crystal lattice(The cell parameter of phosphors decreases with the increment of co-substitution content monotonically. The former is in linear with the latter). The measurement of the excitation and emission spectra shows that the co-substitution of Ca2+ and Si4+ make the emission peak move to short wavelength. The amount of blue shift is also in linear with the co-substitution content.

An integrated digital routine is applied in the near net shape manufacturing of marine propeller. Firstly, the 3D CAD file of propeller is created by parametric modeling. Secondly, the propeller casting process is simulated using CAE software, through which an optimized casting scheme is obtained. Thirdly, fabricates the mold using laser rapid prototyping and cast the metal propeller. Finally, evaluate the casting precision performance. CAD, CAE and CAM are integrated in this process. The dimensional accuracy of the final piece is controlled within 1mm and its surface roughness achieves Ra 6.3μm. The result shows that the pattern-less casting of propeller can be achieved by this method, reducing cost and performing high accuracy.

A novel orthogonal 5-DOF parallel manipulator was proposed, and the statics equations of the 5-DOF parallel manipulator were derived in closed forms based on its layout feature, then the statics transmission indices wer defined, and discussed in detail. It can provide theoretical base for the applications of the 5-DOF parallel machine tool. The novel 5-DOF parallel manipulator can be used as the precision platform in which the requirements for high stiffness, high accuracy and good technological efficiency.