Abstract: The present invention is: a pearlitic steel rail excellent in wear resistance and ductility, characterized in that, in a steel rail having pearlite structure containing, in mass, 0.65 to 1.40% C, the number of the pearlite blocks having grain sizes in the range from 1 to 15 ?m is 200 or more per 0.2 mm2 of an observation field at least in a part of the region down to a depth of 10 mm from the surface of the corners and top of the head portion; and a method for producing a pearlitic steel rail excellent in wear resistance and ductility, characterized by, in the hot rolling of said steel rail, applying finish rolling so that the temperature of the rail surface may be in the range from 850° C. to 1,000° C. and the sectional area reduction ratio at the final pass may be 6% or more, and then applying accelerated cooling to the head portion of said rail at a cooling rate in the range from 1 to 30° C./sec. from the austenite temperature range to at least 550° C.

Abstract: The present invention is: a pearlitic steel rail excellent in wear resistance and ductility, characterized in that, in a steel rail having pearlite structure containing, in mass, 0.65 to 1.40% C, the number of the pearlite blocks having grain sizes in the range from 1 to 15 ?m is 200 or more per 0.2 mm2 of an observation field at least in a part of the region down to a depth of 10 mm from the surface of the corners and top of the head portion; and a method for producing a pearlitic steel rail excellent in wear resistance and ductility, characterized by, in the hot rolling of said steel rail, applying finish rolling so that the temperature of the rail surface may be in the range from 850° C. to 1,000° C. and the sectional area reduction ratio at the final pass may be 6% or more, and then applying accelerated cooling to the head portion of said rail at a cooling rate in the range from 1 to 30° C./sec. from the austenite temperature range to at least 550° C.

Abstract: The present invention is: a pearlitic steel rail excellent in wear resistance and ductility, characterized in that, in a steel rail having pearlite structure containing, in mass, 0.65 to 1.40% C, the number of the pearlite blocks having grain sizes in the range from 1 to 15 &mgr;m is 200 or more per 0.2 mm2 of an observation field at least in a part of the region down to a depth of 10 mm from the surface of the corners and top of the head portion; and a method for producing a pearlitic steel rail excellent in wear resistance and ductility, characterized by, in the hot rolling of said steel rail, applying finish rolling so that the temperature of the rail surface may be in the range from 850° C. to 1,000° C. and the sectional area reduction ratio at the final pass may be 6% or more, and then applying accelerated cooling to the head portion of said rail at a cooling rate in the range from 1 to 30° C./sec. from the austenite temperature range to at least 550° C.

Abstract: A silicon nitride powder prepared by nitriding a metallic silicon powder and having the following physical characteristics (1) to (3):(1) the oxygen content in the form of a solid solution is at most 0.5% by weight,(2) the specific surface area is from 6 to 16 m.sup.2 /g, and(3) the content of fine powder of at most 0.2 .mu.m is at most 7% by volume.

Abstract: An absorption profile indicative of a relation in atomic absorption spectroscopy between the absorbance of a desired element and time has a constant half-width independent of the concentration of the desired element in a sample, and hence the half-width of absorption profile with respect to the desired element can be previously determined from data which is obtained by the measurement of a standard sample. In an atomic absorption spectrophotometer herein disclosed, the half-width of absorption profile is previously determined in the above-mentioned manner, and the true peak value of an absorption profile obtained by measuring a sample which contains the desired element at a high concentration, is calculated using the time width of this absorption profile at a predetermined absorbance and the previously-determined half-width.

Abstract: In a method of analyzing a sample by measuring retention time of the components of the sample, a method of ananlysis by chromatogram which displays schematic chromatograms related to particular fillers and particular object components to be analyzed, relying upon the retention time and half widths of various object components to be analyzed that have been stored and are related to various fillers to be charged into the separation column. The invention further deals with a chromatogram analysis apparatus comprising means which stores the retention time and half widths of objects components to be analyzed related to various fillers that are to be charged into the separation column, and means which prepares schematic chromatograms related to particular fillers. Schematic chromatograms are displayed to efficiently and quickly select a filler that is suited for the analysis of saccharide. The apparatus for analysis can be used independently, or as a component of the chromatograph data processor.

Abstract: An ampoule shaped electrodeless discharge tube, including a large-diameter portion and a small-diameter portion, is filled with luminous elements and inactive gas. The discharge tube is placed in a housing having a lighting window from which the light emitted by the elements is extracted. A high-frequency coil is wound around the large diameter portion at the middle portion of the discharge tube. A partition wall provided in the housing partitions the housing into a first and a second compartments. The middle portion of the discharge tube and the small diameter portion are placed in the first compartment, while the end portion of the discharge tube opposite to the small-diameter portion is placed in the second compartment, and is cooled with air-flow flowing from the inlet to the outlet, both of which are formed to the housing. When high-frequency power is supplied to the coil, the luminous elements in the discharge tube is excited to luminesce.