Abstract.The manganese(II) coordination polymer [Mn(2-Meimi) 2 (μ 1,1 -N 3 ) 2 ] n ·nH 2 O (1) (Meimi = 2-methyl-imidazole) with μ 1,1 -N 3 (end-on, EO) bridge was synthesized by hydrothermal reaction of MnCl 2 , NaN 3 , and Meimi. It was characterized by elemental analysis, IR spectroscopy, powder XRD, and magnetic measurements. Single crystal X-ray analysis revealed that compound 1 features

Laser welding with hot wire addition is a new type of welding method. In order to search for appropriate laser welding technological parameters, main technological parameters have ran orthogonal optimization tests, root face layers have ran orthogonal experiments, impacts on root face forming qualities of technological parameters have been analyzed. Experimental results show that, the most influential technological parameter of weld width is welding speed, by lowering welding speed heat heat input in per unit of time will be increased, weld width decreases with the increase of defocusing amount and decrease of density of power.

A lap welding experiment of DP590 steel and 6061 aluminum plate is carried out by using Heating Friction Stir Spot Welding (HFSSW) to study the influence of welding parameters on the forming quality. The results show that a lap joint with better forming can be obtained for the dissimilar metal of steel and aluminum. Under the condition that the rotating speed of the stirring tool is 1000r/min, the penetration depth, 0.2mm, the dwell time, 90s, the welding pressure, 0.2Mp, and the flow rate of cooling air, 20L/min, the forming quality of the surface of the joint line is good & bright, and the exit hole is also smaller. The mechanism of heat production is revealed in the following: the main heat is produced by the friction between the stirring tool shoulder and the welded part & between the probe and the welded part as well as by the latent heat resulted from the plastic deformation of the material in joint line during welding.

Laser bonding welding test of the lap joint between steel and Al was conducted. The microstructure analysis is carried out by means of metallographic microscope, which provides an important theoretical and experimental basis for the popularization and application of laser welding of steel / aluminum dissimilar metal structures. The results showed that under the conditions of 1650W laser power, 35m/s welding speed, +3mm defocus amount and 25L/min flow rate of Ar as the protective gas, there are no cracks, pores and inclusions in the weld zone. The fusion line is smooth and smooth. Under the conditions of 1650W laser power, 38m/s welding speed, +3mm defocus amount and 25L/min flow rate of Ar as the protective gas, the overall appearance of the weld zone of the laser welding joint, there are serious cracks, pores and other defects in the weld area. In the P=1680W, V=35mm/s, f=+1mm, q=20L/min, the crystal structure appeared, in the process of cooling, the crack expands and forms a radial shape under the action of internal stress.