Abstract: An organophosphorus compound having the formula: ##STR1## wherein each of X.sub.1, X.sub.2 and X.sub.3 is a hydrogen atom; an alkyl, alkoxy or alkenyl group which may be substituted by halogen, alkoxy, alkylthio, cycloalkyl or phenyl; a phenyl group which may be substituted by halogen; or a cycloalkyl group, each of Y.sub.1, Y.sub.2 and Y.sub.3 is an oxygen atom or a sulfur atom, Z is a carbonyl group; or a methylene group which may be substituted by a cycloalkyl group, by a phenyl group which may be substituted by halogen, or by an alkyl, alkoxy or alkenyl group which may be substituted by halogen, alkoxy alkylthio, cycloalkyl or phenyl, and each of R.sub.1 and R.sub.2 is an alkyl group which may be substituted by halogen, alkoxy or alkylthio.

Abstract: An organophosphorus compound represented by the general formula: ##STR1## where each of X.sub.1 and X.sub.3 is a hydrogen atom; an alkyl or alkoxy group which may be substituted by halogen, alkoxy, alkylthio, phenoxy, halogenated phenoxy, phenylthio or halogenated phenylthio; a carboxyl group; an alkoxycarbonyl group; or a phenyl group which may be substituted by halogen, each of X.sub.2 and X.sub.4 is a hydrogen atom or an alkyl group, provided that X.sub.2 and X.sub.3 may together form an alkylene group, each of Y.sub.1, Y.sub.2 and Z is an oxygen atom or a sulfur atom, and each of R.sub.1 and R.sub.2 is an alkyl group.

Abstract: A 2-substituted-5-trifluoromethylpyridine compound represented by Formula (I): ##STR1## wherein X is a hydrogen atom or a halogen atom, and Y is a cyano group or a carboxy group, provided that Y is a cyano group, then X is a halogen atom, or a salt thereof, and a process for the production of the same. This compound is useful as an intermediate for the production of various fine chemicals.

Abstract: A novel O-(N-alkoxy-pyridinecarboximidoyl)-phosphate represented by the following formula: ##STR1## wherein X is a halogen atom, a lower alkyl group, a lower acyloxy group, a trifluoromethyl group or a nitro group; Y is an oxygen atom or a sulfur atom; R is a lower alkyl group; n is an integer of 0 to 3; and Z.sub.1 and Z.sub.2 are each a lower alkoxy group, a lower alkylthio group, a phenyl group which may be substituted by a lower alkyl group, a phenoxy group, a haloalkoxy group or a lower alkylamino group, useful as an active ingredient of insecticides or acaricides.

Abstract: A boost compensator controls the position of a fuel injection control rack in response to the induction air pressure and a centrifugal flyweight assembly increases the fuel injection volume when the engine speed is below a predetermined value. The boost compensator is provided with a releasing spring so that the control rack can be moved by the flyweight assembly independently of the boost compensator. An engine oil pressure sensor provides a maximum fuel injection volume for starting the engine when the oil pressure is zero and automatically decreases the fuel injection volume as the engine starts and the oil pressure rises to an operating value.