Abstract: An optoelectronic device (LV) with a reflective composite material (V) having a carrier (1) consisting of aluminium, having an interlayer (2) composed of aluminium oxide present on one side (A) of the carrier (1) and having a reflection-boosting optically active multilayer system (3) that has been applied via the interlayer (2). The interlayer (2) consisting of aluminium oxide has a thickness (D2) in the range from 5 nm to 200 nm and that, on the opposite side (B) of the carrier (1) from the reflection-boosting optically active multilayer system (3), a superficial layer (9) of a metal or metal alloy having, at 25° C., a specific electrical resistivity of not more than 1.2*10?1 ?mm2/m has been applied. The thickness (D9) of the superficially applied layer (9) is in the range from 10 nm to 5.0 ?m.

Abstract: Method for monitoring the velocity of growing polymer particles flowing in a two-phase stream during a polymerization process, said method comprising measuring the degree of attenuation in the propagation of light in said two-phase stream by means of a photometric instrument, said photometric instrument comprising: one or more transmitting optical waveguides connecting one or more light sources to said two-phase stream, one or more receiving optical waveguides connecting said two-phase stream to a light detector.