Abstract: An object is to prevent eavesdropping in quantum key distribution. A decoding unit decodes a quantum signal incident thereinto. A plurality of detect photons of the decoded quantum signal output from the decoding unit. A signal processing unit detects bits of the decoded quantum signal based on photon detection results of the plurality of detectors. A control unit perform switching processing by switching destinations to which two decoded quantum signals corresponding to one encoding basis are output between the plurality of detectors, and switching the bits detected by the signal processing unit based on the respective photon detection results of the plurality of detectors.

Abstract: An object is to prevent eavesdropping in quantum key distribution. A photon detector outputs an output current indicating a result of detecting a quantum signal. A current-voltage conversion unit converts the output current into an output voltage signal. An analog-to-digital converter outputs an output voltage signal obtained by analog-digital conversion of the output voltage signal. A signal processing unit performs predetermined signal processing on the output voltage signal, and outputs a photon detection signal indicating a result of detecting the quantum signal. When a time difference between a timing at which the quantum signal is incident into the photon detector and a reference timing determined based on a clock signal is not within a determination range, the photon detection signal is not output from the signal processing unit.

Abstract: A polyester product is treated with a treatment liquid containing at least one of dibromophenyl derivatives represented by the following general formula: ##STR1## wherein Y is --SO.sub.2 -- or --C(CH.sub.3).sub.2 --, each of R.sub.1 and R.sub.2 is --H, --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7 OH, --CH.sub.2 CH.sub.2 Br or --(CH.sub.2 CH.sub.2 O).sub.n H and n is a positive integer of from 1 to 9 to obtain a flame retardant polyester fiber product. The polyester product may be further treated with an oligomer of vinyl phosphonate which is present either in the above treatment liquid with the dibromophenyl derivative or in a separate treatment bath from the above treatment liquid.

Abstract: A fabric is coated with a composition which comprises a thermoplastic polyurethane and a sulfone having the following general formula ##STR1## wherein R represents --H, --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7 OH, --CH.sub.2 CH.sub.2 Br or --(CH.sub.2 CH.sub.2 O).sub.n H and n is a integer of 1 to 5, and preferably a polyisocyanate as a cross-linking agent.

Abstract: A fabric is coated with a composition which comprises a thermoplastic polyurethane and 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane derivative having the following general formula ##STR1## wherein each n1 and n2 represents zero or a positive integer and n1 + n2 is zero or one of the integers from 1 to 8, and preferably a polyisocyanate as a cross-linking agent.

Abstract: A polyester article is treated with an aqueous emulsion of a halogenated phosphoric ester to retard its flammability. The aqueous emulsion is prepared by emulsifying a halogenated phosphoric ester with a nonionic surfactant derived from a phosphoric ester.