This study aimed to determine the impact of dentinal tubule orientation on dentin bond strength to provide a reference for clinical cavity preparation in resin-bonded restoration. Patients aged 13-16 years were selected, including 18 males and 21 females. Forty-eight human maxillary first premolars from orthodontic extractions were chosen to prepare the test models with the dentinal tubule orientations perpendicular and parallel to the bonding substrate. The test models in the vertical and parallel groups were divided into three groups: total-etching with 20% phosphoric acid, total-etching with 35% phosphoric acid and self-etching, with the dentinal tubule surfaces bonded with composite resin blocks in each group. After the standard test models of dentinal tubule-composite resin blocks were placed in distilled water and stored at 37°C for 24 h, shearing tests were performed using a universal material testing machine at a crosshead speed of 0.5 mm/min. The bond strength values in the vertical group were 19.33±1.59 MPa for the 20% phosphoric acid group, 21.39±2.34 MPa for the 35% phosphoric acid group, and 16.88±1.54 MPa for the self-etching group. The bond strength values in the parallel group were 24.53±1.99 MPa for the 20% phosphoric acid group, 25.16±2.88 MPa for the 35% phosphoric acid group, and 20.83±1.99 for the self-etching group. After using same total-etching adhesive, the shear bond strength of the parallel group was higher than that of the vertical group, and the difference was statistically significant (P<0.05). Regardless of vertical group or parallel group, the difference in the bond strength value between the total-etching groups and the self-etching group was statistically significant (P<0.05). It was concluded that the dentin bonding substrate which was parallel to the direction of the dentin tubule achieved an improved bond strength; the total-etching adhesives achieved higher bond strengths in dentin bond than the self-etching adhesives.

In the process of urban construction, the implementation of various engineering projects will lead to a series of social problems. If these problems are not effectively resolved, they will be further upgraded into social risks and have a negative impact on social order. At present, China’s social risk assessment methods mainly include expert scoring and expert sorting. The paper takes the method of expert sorting as the main research object. Based on the ordered voting model, this paper further analyses the scientific nature of the ranking method from the aspects of single index evaluation and multi-index evaluation.

The government website is an important tool for the government to improve administrative efficiency and public service. Just as traditional government management needs performance evaluation, government websites also need performance evaluation. Based on the theory of Balanced Scorecard (BSC), this article puts forward a set of BSC performance evaluation index system for government websites and uses analytic hierarchy process (AHP) to establish the weight of all levels of indicators in the system. According to the characteristics of website performance evaluation, the qualitative and quantitative indicators are disposed in a unified fuzzy processing, and the performance of government websites is evaluated objectively and impartially by multi-level fuzzy evaluation method, which provides a scientific and feasible method for promoting the performance of government websites.

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Through laboratory experiments, a green cross-linked movable gel has been developed, which has been used for reservoir profile modification. The main agent of gel is hydrophobic associating polymer, concentration is 3000mg/L; the cross-linking agent is Aluminum citrate from complex of Aluminum ion and citric acid root ion. The best molar ratio of aluminum ions and citrate ions is 1.5:1 in complex reaction, the amount is 140mg/L; the retarder is tartaric acid sodium, the amount is 150mg/L; The stabilizer is thiourea, the amount is 800mg/L; The strength of the green cross-linked movable gel is 3.12×104mPa.s, gelling time 36h, Stable time 160d; It is suitable for low-temperature reservoir profile modification, and salt resistance is good. Laboratory experiments show that the green cross-linked movable gel have strong plugging capacity and improving profile ability. The green cross-linked movable gel has strong three dimensional network structure, which be observed through the environmental scanning electron microscopy.