Abstract: The invention describes the synthesis of novel mono-amine and di-amine derivatives of hexa-nitro-hexaazaisohexawurtzitane (CL-20). The synthesis is affected by the novel use of fluoroacylating compounds to protect the secondary amine groups of acylated precursors to CL-20 against nitrolysis. In so doing the mono-amine and di-amine derivatives of CL-20 are rendered and which in turn may be subsequently utilized as intermediates to generate further novel derivatives with differing physical and chemical properties to the parent compound. Formula (I), wherein: —X?H, and Y?H or NO2.

Abstract: A navigation system comprising an RLG (6), means for inducing an oscillatory phase change in the output of the laser of the RLG which simulates an oscillatory dither whose amplitude is in excess of the sum of a defined lock-in range and a defined, narrower control zone, and means (3) for activating said oscillatory dither when the rotation rate applied to said RLG is within said control zone but to apply to the laser output a dither fixed at its full amplitude in the sense of the rotation rate applied to the RLG whenever said rotation rate is outside said defined control zone. Means (9) are preferably provided for applying to the laser output a dither output fixed at its full amplitude in the opposite sense and for the same period as a fixed dither output has previously been applied, provided that the applied rate is not outside said control zone in the original sense.

Abstract: A non-linear optical device comprises a crystalline, second harmonic generator material mounted in the optical path of a laser, in which the crystalline material consists of a slat of a chiral carboxylic acid and an organic nitrogenous base which has a noncentrosymmetric crystal structure.

Abstract: A thermal detector comprises a thin film diode transistor coated with infrared absorbent material, and mounted on a thermally insulating support such as silicon oxide, foam glass or foam plastics material. The support may be recessed to improve insulation. The detector may be an array of diodes or transistors, and the diodes may be LEDs. Addressing may be line-by-line or co-ordinate selection. A transistor detector array may be arranged for signal integration and sample switching. A chopper may be used to modulate radiation illuminating the detector, whose output is fed to subtractive circuitry. Alternatively, a transistor detector array may incorporate additional transistors for bias current subtraction, each detecting transistor forming a long-tailed pair configuration with a respective additional transistor.