This study explores an improved method of welding austenitic stainless steel. The method uses two series connected arcs to weld the workpiece simultaneously from opposite sides. Owing to this arc configuration, the welding current is forced to flow from one arc to the other through the workpiece. It is known that such current flow concentrates the arcs and thus improves the penetration capability. Also, the current flowing through the workpiece generates fluid flow within the weld pool. In addition, owing to the use of the two opposite arcs, the heating tends to be symmetric. In addition to the increased penetration, the use of this method for welding austenitic stainless steel results in improved microstructure in the resultant welds because of an increased columnar to equiaxed transition and a decreased angular distortion, which sometimes induces solidification cracking.

利用扩散火焰合成碳纳米管是一项新的技术和方法。介绍了这种新方法的基本原理，较系统地研究了火焰参数、基板材料、合成时间等对碳纳米管形态的影响。初步研究表明它在无外加催化剂的情况下也能合成碳纳米管，具有“自生催化”的特点。

Due to its popularity and high crack sensitivity, 6061 aluminum alloy was selected as a test material for the newly developed double-sided arc welding (DSAW) process. The microstructure, crack sensitivity, and porosity of DSAW weldments were studied systematically. The percentage of fine equiaxed grains in the fully penetrated welds is greatly increased. Residual stresses are reduced. Porosity in the welds is reduced and individual pores are smaller. It was also found that the shape and size of porosity is related to solidification substructure. In particular, a weld metal zone with equiaxed grains tends to form small and dispersed porosity, whereas elongated porosity tends to occur in columnar grains.

This paper introduces a process to synthesize well aligned carbon nanotubes (CNTs) from ethanol flames by using a uniform electric field generated from a DC power supply. It has been found that (1) comparing with the other processes a small electric field is enough to align CNTs; (2) the synthesis process becomes more controllable and repeatable; (3) the electric field also improves the diameter uniformity and the crystallinity of graphite sheets. It is thought that the alignment mechanism is due to the electrostatic force acting upon the catalyst particles at the tips of CNTs. The present process has advantages such as convenience of applying electric field, simple experiment set-up, and large area synthesis of well aligned CNTs.