Abstract: A case nitrided aluminum product is produced by contacting an aluminum product with a nitriding agent at a part of a surface thereof at least, and by nitriding the aluminum product at the surface with an ambient gas at a temperature of a melting point of the aluminum product or less while keeping the aforementioned contact. The nitriding agent includes an aluminum powder, and the ambient gas virtually includes a nitrogen gas. The resulting nitriding layer has a depth of 5 micrometers or more, and it exhibits a case hardness of from 250 to 1,200 mHv. Thus, it is possible to form the deep and hard nitriding layer on the aluminum product with ease under the conditions where it has been said to be too difficult to nitride aluminum products. The case nitrided aluminum product can appropriately make sliding parts which require high wear resistance.

Abstract: The surface of material containing a hydrogen storage alloy are treated with an organometallic compound to provide the alloy with corrosion resistance.

Abstract: A method is disclosed for calibrating a reflectometer using black and white references observed in locations optically different from the sample location. Dark and light standards are selected to have reflectance values, while examined in the detection location of the test elements, that are within .+-.0.005 and .+-.0.05 of the values of the black and white references, respectively, when examined in a location displaced from the detection location of the test elements. Such standards are then read on a referee reflectometer having "ideal" black and white references, and the reflectances so read on the referee reflectometer are recorded for use as calibrating factors in making reflectance readings for the test elements.

Abstract: In an optical detection system for detecting a feature located at a predetermined lateral position on a banknote, for example, the banknote is moved along a flow path and a series of light receivers are arranged transversely across that portion of the flow path which the feature is expected to occupy, so that different ones of the light receivers will respond to the feature in the banknote depending on the lateral offset of the banknote at that portion of the flow path. The margins of the note are utilized in the detection system to gate the said light receivers so that for any position of lateral offset of the banknote only that light receiver which responds to the said feature of the banknote will produce an effective output signal. In the embodiment of FIG. 1, two sets of fibre optics are used to effect this gating, one set having its first ends (S1 to S5) opposite a light source at one margin of the sheet and its other ends (F1 to F5) adjacent the above mentioned light receivers (F1' to F5').

Abstract: A thin, compact reflectometer is adapted to support and position a generally planar test element in a predetermined, generally horizontal plane during usage. The reflectometer includes a light source and a detector having major portions of their respective illumination and detection axes extending generally parallel to a planar reflectometer-positioning portion on one of two major surfaces of the reflectometer.