GOVERNMENT CONTRACT AWARDS

* Sierracin-Sylmar, Sylmar, won a $934,980 contract from the Navy in Philadelphia for aircraft windshields.

* Arete Associates, Sherman Oaks, won a $399,000 contract from the Defense Special Weapons Agency in Alexandria, Va., for research and development.

* Semco Instruments Inc., Valencia, won a $365,484 contract from the Defense General Supply Center in Richmond, Va., for electrical components.

* Litton Systems Inc., Northridge, won a $317,783 contract from the Navy in Philadelphia for power equipment.

* Whittaker Corp., North Hollywood, won a $310,398 contract from the Defense Supply Center in Columbus, Ohio, for electrical components.

* Glesby Building Materials, Van Nuys, won a $293,319 contract from the Army in Rock Island, Ill., for construction materials.

* Litton Systems Inc., Woodland Hills, won a $192,315 contract from the Navy in Philadelphia for electrical components.

* HR Textron Inc., Valencia, won a $110,056 contract from the Defense Supply Center in Columbus, Ohio, for instruments and laboratory equipment.