Abstract. With the increasing of the amount of the scientific papers, it is very important and difficult for paper-sharing platforms to recommend related papers accurately for users. This paper tackles the problem by proposing a method that models user historical behavior. Through collecting the operations on scientific papers of online users and carrying on the detailed analysis, we build preference model for each user. The personalized recommendation model is constructed based on contentbased filtering model and statistical language model.. Experimental results show that users' historical behavior plays an important role in user preference modeling and the proposed method improves the final predication performance in the field of technical papers recommendation.

No abstract

The corrosion behavior of 3% Cr steel is tested by a high-temperature/high-pressure autoclave. The corrosion environment is categorized into CO 2 -alone and CO 2 /H 2 S conditions. At 90°C, with the addition of H 2 S to the CO 2 , the surface corrosion condition improved greatly, and the corrosion rates declined compared with the CO 2 -alone condition. Under CO 2 /H 2 S condition, with an increasing CO 2 /H 2 S partial-pressure ratio, the corrosion rate reached a peak value at pCO 2 /pH 2 S=100, and then declined. Through the analysis of the corrosion products of the samples in different conditions by scanning electron microscope (SEM), EDS, and X-ray-diffraction (XRD) methods, it was found that the inner film is finer and denser than the outer scale. The partial-pressure ratio of H 2 S corrosion regime should be between 10 and 100 and is not the previous 200.

No abstract

An experimental study was carried out to assess the effects of silty sand on the CO 2 corrosion behavior of 1 wt% Cr (1Cr) and 3 wt% Cr (3Cr) tubing steel under 0.5 MPa CO 2 at 100°C and 1.5 m/s flow velocity. The 1Cr and 3Cr specimens both suffered general corrosion, but the surface was coarser in the pure CO 2 corrosion environment. Under silty sand conditions, severe pitting corrosion occurred on the 1Cr specimens and some acicular pitting appeared on the 3Cr specimens. The average corrosion rates of 1Cr and 3Cr steels increased by factors of 3 and 1.6, respectively. The corrosion products were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and electrical impedance spectroscopy (EIS). The results show that silty sand acts as an inclusion in corrosion product films and reduces the homogeneity and density of the products, rather than abrading the corrosion film. Ion-diffusion channels may build up around the irregular silty sand; this would degrade the protective capabilities of the product films and aggravate corrosion. low-Cr tubing steel, CO 2 corrosion, silty sand, ion-diffusion channel Citation:Yan W, Deng J G, Li X R, et al. Effects of silty sand on CO 2 corrosion behavior of low-Cr tubing steel. Chin Sci Bull, 2012, 57: 927-934,

No abstract

No abstract

No abstract