Abstract: The present invention provides a process for producing a porous quartz glass base, which comprises hydrolyzing a silicon compound in an oxyhydrogen flame in a reaction furnace to generate and deposit fine silica particles on a starting member, thereby forming a porous quartz glass base, wherein a gas discharge pipe for discharging an unnecessary gas from the reaction furnace is heated. According to the present invention, fine silica particles can be prevented from adhering to a gas discharge pipe for discharging the unnecessary hydrogen chloride gas generated in producing a porous quartz glass base.

Abstract: The present invention provides a process for producing a porous quartz glass base, which comprises hydrolyzing a silicon compound in an oxyhydrogen flame in a reaction furnace to generate and deposit fine silica particles on a starting member, thereby forming a porous quartz glass base, wherein a gas discharge pipe for discharging an unnecessary gas from the reaction furnace is heated. According to the present invention, fine silica particles can be prevented from adhering to a gas discharge pipe for discharging the unnecessary hydrogen chloride gas generated in producing a porous quartz glass base.

Abstract: A business supporting system extracts prospective customers to whom purchase of a new product is to be proposed, based on properties of products, relations between the products, purchase history and so forth. Moreover, prospective customers may be extracted based on results of previous purchases, accounting data analysis and customer trouble analysis, so as to meet requirements of a seller and to also meet the needs of customers. Extracting conditions can be defined at the seller's option.