Disclosed are novel benzo-, naphtho- and phenanthrochromenes substituted by carbamated or ureated phenyls having the following general formula :wherein R1 represents a grouptheir preparation, photochromic compositions and articles containing them. Actual NOx emissions produced by the engine are filtered using a variable NOx time constant in turn correlated to the reductantNOx storage capacity of the reducing catalyst at its current temperature to account for changes in the SCR system attributed to NOx transient emissions. At least one second limb has both a distal portion and a proximal portion coupled to the second side of the center support. The optimized correction is then followed by a complementary refractive correction \u201cd2\u201d wherein stromal tissue is weakened with Laser Induced Optical Breakdown. The phase windings of the first and second wye windings are configured by connecting two winding portions in parallel, and those two winding portions are configured such that distributions of radial positions inside slots of conductor wires that constitute the winding portions are equal. A recess is provided between the rotor and a slide face of the brush and the commutator, where powder produced by abrasion at the brush may enter into a motor and increase sliding resistance of the rotor.