Process for the production of oriented grain electrical steel strips, in which a silicon steel, comprising at least 30 ppm of S, is directly cast as strip 1. Because a compound of formula have an activity of regulating peroxisome proliferator activated receptor regulator, the compound of formula is useful as a hypoglycemic agent, a hypolipidemic agent, a preventive andor treatment agent for diseases associating metabolic disorders, hyperlipemia, atherosclerosis, hypertension, circulatory diseases, overeating, ischemic heart diseases, etc. Mirrors positioned at the intersection of each side of the polygon-shaped closed loop passage create an optical closed loop path through passage. The next step involves heating the first and second housing shells in the area of the seam, such that the first and second end caps are fused together.