Abstract: A graphene and in-situ nano-ZrB2 particle-co-reinforced aluminum matrix composite (AMC) and a preparation method thereof are provided. The preparation method includes: heating an aluminum alloy for melting, adding potassium fluoroborate and potassium fluorozirconate to produce ZrB2 particles in-situ, additionally adding a mixture of pre-prepared copper-coated graphene and an aluminum powder, and stirring with an electromagnetic field for uniform dispersion; and ultrasonically treating the resulting melt to improve the dispersion of the in-situ nano-ZrB2 particles and the graphene, casting for molding to obtain a casting, and subjecting the casting to homogenization and rolling for deformation to obtain the graphene and in-situ nano-ZrB2 particle-co-reinforced AMC. The in-situ generation of the reinforcement nano-ZrB2 particles in an aluminum alloy melt increases the number of interfaces in the composite and also increases the dislocation density.

Abstract: A graphene and in-situ nano-ZrB2 particle-co-reinforced aluminum matrix composite (AMC) and a preparation method thereof are provided. The preparation method includes: heating an aluminum alloy for melting, adding potassium fluoroborate and potassium fluorozirconate to produce ZrB2 particles in-situ, additionally adding a mixture of pre-prepared copper-coated graphene and an aluminum powder, and stirring with an electromagnetic field for uniform dispersion; and ultrasonically treating the resulting melt to improve the dispersion of the in-situ nano-ZrB2 particles and the graphene, casting for molding to obtain a casting, and subjecting the casting to homogenization and rolling for deformation to obtain the graphene and in-situ nano-ZrB2 particle-co-reinforced AMC. The in-situ generation of the reinforcement nano-ZrB2 particles in an aluminum alloy melt increases the number of interfaces in the composite and also increases the dislocation density.

Abstract: Generating pseudorandom test items for software testing of an Application Under Test (AUT) is provided. In one example, a method comprises selecting an oracle of one or more oracles within a test provider directory structure, the oracle defining one or more logical paths each comprising one or more test conditions and an expected result. A pseudorandom test item having an initial state of empty is generated, and a logical path of the one or more logical paths is selected. The one or more test conditions of the logical path are translated into a constraint. Based on the constraint, a pseudorandom test input is generated and stored in the pseudorandom test item in association with the expected result corresponding to the logical path.

Abstract: Generating pseudorandom test items for software testing of an Application Under Test (AUT) is provided. In one example, a method comprises selecting an oracle of one or more oracles within a test provider directory structure, the oracle defining one or more logical paths each comprising one or more test conditions and an expected result. A pseudorandom test item having an initial state of empty is generated, and a logical path of the one or more logical paths is selected. The one or more test conditions of the logical path are translated into a constraint. Based on the constraint, a pseudorandom test input is generated and stored in the pseudorandom test item in association with the expected result corresponding to the logical path.