Abstract: The present invention provides a novel dipeptide compound or pharmaceutically acceptable salt thereof which exhibits an excellent HIV protease inhibitory activity and an excellent bioavailability from digestive tracts, and an anti-AIDS agent comprising said dipeptide compound as an effective ingredient.General formula (I): ##STR1## (wherein R.sub.1 represents 5-membered or 6-membered monocyclic hydrocarbon group or heterocyclic group wherein more than one carbon atom of said monocyclic hydrocarbon group is substituted with hetero atom. X represents methylene group (--CH.sub.2 --), chloromethylene group(--CH(Cl)--), oxygen atom sulfur atom or sulfonyl group (--SO.sub.2 --). R.sub.21 and R.sub.22 each represents hydrogen atom or aliphatic hydrocarbon group having 1-6 carbons. R.sub.3 represents aliphatic hydrocarbon group or monovalent group derived from aromatic monocyclic hydrocarbon having 1-6 carbons.

Abstract: A novel method is proposed for concurrently producing a metallic copper powder and a valuable chloride of a metal other than copper, e.g., manganese, zinc, cobalt, nickel and tin, from a depleted aqueous etching solution containing copper (II) chloride as discharged from the etching process in the manufacture of copper-foiled printed circuit boards. The inventive method also contributes to solve the problem for the disposal of such a waste solution without causing the troubles in connection with environmental pollution. The inventive method comprises the steps of: treating the waste solution with an active carbon so as to remove organic impurities; admixing the solution with a powder, granules or flakes of the above mentioned metal so as to precipitate the copper value in the metallic form, instead, giving an aqueous solution of the chloride of the added metal; and separating the copper metal powder and the chloride solution.

Abstract: An information processing system including an input/output section, a memory section, and a data processing section for communicating data via the memory section in block units between the input/output section and the data processing section to effect a processing characterized in that a signal indicating an end of the processing in block units is supplied from the data processing section to the input/output section and that a processing start timing signal formed depending on the signal indicating the processing end delivered from the output section is delivered to the data processing section, the processing start timing signal being synchronized with a data block period.

Abstract: An information processing apparatus comprising a program supplying portion, write signal generator, and a data processor, which includes a microprogram controller, microprogram memory, arithmetic unit, and a selector for selecting in an alternative way an address from the microprogram controller and an address from the program supplying portion and supplying the same to the microprogram memory.