Abstract: A method for operating a shaft furnace which comprises charging the furnace with an iron source having a low degree of metallization and thus requiring reduction, an iron source having a high degree of metallization and thus requiring nothing but melting, and a solid fuel, and blowing an oxygen-containing gas at ordinary or higher temperature up to 600.degree. C. into the furnace through tuyeres to reduce and melt the iron sources. The optimal values of .eta.co (gas utilization factor) are determined from the average degree of metallization of the iron sources, and the shaft furnace is controlled so that the effluent gas from the furnace has the optimal .eta.co values. The control is accomplished by regulating the height of the charge, regulating the height of the coke bed, etc., using multistage tuyeres, and radially partitioning the charge. Thus, the iron sources can be efficiently reduced and melted at a low fuel ratio.

Abstract: An electronic component carrier includes an elongated substrate having a series of electronic component-setting portions spaced from one another at a predetermined interval along the length of the substrate. The substrate has push bar-insertion holes formed therethrough and disposed respectively at the electronic component-setting portions. Adhesive layers are formed respectively on surfaces of the electronic component-setting portions. The electronic components are adapted to be bonded respectively to the electronic component-setting portions through the adhesive layers. A push bar is adapted to be inserted into the push bar-insertion hole so as to be engaged with the electronic component to release the same from the adhesive layer.