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Abstract. Proof-Carrying Code brings two big challenges to the research field of programming languages. One is to seek more expressive logics or type systems to specify or reason about the properties of lowlevel or high-level programs. The other is to study the technology of certifying compilation in which the compiler generates proofs for programs with annotations. This paper presents our progress in the above two aspects. A pointer logic was designed for PointerC (a C-like programming language) in our research. As an extension of Hoare logic, our pointer logic expresses the change of pointer information for each statement in its inference rules to support program verification. Meanwhile, based on the ideas from CAP (Certified Assembly Programming) and SCAP (Stack-based Certified Assembly Programming), a reasoning framework was built to verify the properties of object code in a Hoare style. And a certifying compiler prototype for PointerC was implemented based on this framework. The main contribution of this paper is the design of the pointer logic and the implementation of the certifying compiler prototype. In our certifying compiler, the source language contains rich pointer types and operations and also supports dynamic storage allocation and deallocation.

The tribological performance of a compression ring-cylinder liner system (CRCL) is numerically studied. A thermal-mixed lubrication model is developed for the lubrication analysis of the CRCL with consideration of the cylinder liner deformation. An oil transport model coupled with a mass conservation cavitation algorithm is employed to predict the oil consumption and the transition between the fully flooded lubrication condition and starved lubrication condition. On this basis, the effects of the oil supply and cylinder liner deformation on the frictional characteristics are investigated under cold and warm engine conditions. The results show that the cylinder liner deformation and oil supply have great influence on the tribological performance of the CRCL. Better tribological performance and lower oil consumption can be obtained by reasonably controlling the oil supply.

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Some laboratory experiments are carried out to study the effect of different refractories on the original and exogenous inclusions in Si-Mn-killed steel. As expected, it is found that Al 2 O 3 refractory causes high melting points of both SiO 2 -Al 2 O 3 -MnO system and SiO 2 -Al 2 O 3 -CaO system inclusions, while MgO crucible reduces the melting points of both systems of inclusions to a certain extent. The purity of MgO refractory is crucial for tire cord steel grades, and even 0.3% of Al 2 O 3 impurity in refractory results in an evident increase (by 10%-20%) of Al 2 O 3 content in the inclusions. Similar to Al-killed steel grades, MgO·Al 2 O 3 spinel can also be stable in Si-Mn-killed steel due to the effect of MgO refractory, and MgO and Al 2 O 3 inclusions can transform into MgO·Al 2 O 3 spinel. These inclusions should be strictly controlled during refining process. High-purity and high-quality MgO refractory as well as high-quality alloys are recommended for Si-Mn-killed steel grades, and Al 2 O 3 -based refractory should be avoided.