Abstract The interfacial stress in a carbon fiber-reinforced polymer (CFRP) plate for strengthening the top flange of a box-girder bridge was theoretically investigated. According to the force analysis results of the box-girder structure, the most unfavorable force area was selected for modeling analysis. Using the simplified beam model, a CFRP plate-concrete interfacial-stress calculation model was derived, and the closed-form solution of the calculation model was obtained. Equivalent simplified test specimens were designed according to the box-girder structure to verify the reliability of the theoretical model. Then, four-point bending tests of the sample were performed. In these tests, the debonding failure modes and strain in the CFRP plate were examined. The CFRP plate-concrete interfacial stress was calculated according to the strain data of the CFRP plate in the experimental tests. Then compared the experimental results with the theoretical results. Furthermore, the corresponding interfacial stresses were calculated and compared according to the different load levels specified in the code. A series of theoretical and experimental comparisons were performed to verify the reliability of the proposed CFRP-concrete interfacial stress closed-form solution model.

Abstract This paper investigated the fatigue properties and theoretical research on Carbon-Fiber-Reinforced Polymer (CFRP) RC bridge roof with new deck-pavement material. Two deck pavement schemes of CFRP-reinforced specimens were designed and tested. Four-point flexural fatigue tests were carried out on the specimens. The fatigue crack propagation, the deflection development and the CFRP strain under bridge fatigue load were researched. The test results show that the CFRP plate-reinforced specimens crack resistance performance can be improved and can bear the fatigue test load of two million times. Combined with the characteristics of the crack growth rate and fatigue damage accumulation of CFRP plate-reinforced bridge roof specimens, the fatigue life prediction analytical model for CFRP plate reinforced RC bridge roof was obtained. The fatigue life prediction model agrees well with the experimental results. The model proposed in this paper could be applied to predict the fatigue life of the CFRP plate-reinforced RC bridge roofs.

Abstract The bond-slip relationship of Carbon Fiber Reinforced Polymer (CFRP) plate-concrete after the influence of high temperature action of Stone Mastic Asphalt (SMA) paving was investigated in this article. Two groups of double shear specimens with different bonding length were designed and tested. Based on the test results, the failure modes of specimens, the strain distribution and the shear stress of CFRP-concrete interface were analyzed. Considering the influence of high temperature, the interfacial bond-slip constitutive model of CFRP plate and concrete after high temperature action of SMA paving construction was proposed. The proposed model can reflect the nonlinearity and interface softening behaviour of the CFRP plate-concrete interface constitutive relationship under special environment. Through the comparative study of exixting constitutive models, the interface bond-slip constitutive model proposed in this paper considers the effect of high temperature and has good agreement with the test results.

Abstract This paper investigates the crack and mechanical behavior of CFRP plate-reinforced bridge roof under high temperature with different anchoring measures. Six CFRP-reinforced test beams with different anchoring schemes were designed and constructed. The beam specimens, after the high temperature effects, were tested under four-point bending loads. The crack propagation, beam deflection, mid-span strain and the damage modes were observed and recorded until failure. The stiffness variation and the debonding failure mechanism of the test beams were comparatively investigated. The results indicate that the debonding bearing capacity of the specimens can be improved by the additional anchoring measures. The concrete shrinkage at the crack and the average crack spacing are more effectively reduced, when the additional anchoring measures are placed at the mid-span and the support position. In addition, a theoretical model is proposed for calculating the intermediate crack debonding bearing capacity. Based on the comparative analysis of various models and test results, it is shown that the proposed model could accurately calculate the intermediate crack debonding bearing capacity of the test specimens.

Abstract A balanced-to-single-ended (BTSE) Wilkinson power divider of planar microstrip structure is proposed in this paper. It has a balanced input and two single-ended outputs. Cascade of a balun and a conventional power divider can be replaced by this proposed structure. Based on the theory of mixed-mode S parameters and the admittance matrix method, the critical parameters are determined. The four-port network is analyzed by simplifying it to two-port network with other ports matched at the central frequency. Then the key parameters are derived and the impact of a freely selected variable on the bandwidth is also discussed. An example of 2.4GHz BTSE power divider is designed. The simulated and measured results show the effectiveness of the method: differential-mode transmissions are better than −3.25dB, common-mode transmissions are lower than −28.6dB, common-mode return loss is −0.10dB, differential-mode return loss and isolation is lower than −23.7dB. While the operating bandwidth is 20%.

Background Fatty acid synthase (FAS) is a key enzyme of de novo lipogenesis (DNL), which has been cloned from several species: Gallus gallus, Mus musculus, Homo sapiens, but not from Anas platyrhynchos. The current study was conducted to obtain the full-length coding sequence of Peking duck FAS and investigate its expression during adipocyte differentiation. Results We have isolated a 7654 bp fragment from Peking duck adipocytes that corresponds to the FAS gene. The cloned fragment contains an open reading frame of 7545 bp, encodes a 2515 amino acid protein, and displays high nucleotide and amino acid homology to avian FAS orthologs. Twelve hour treatment of oleic acid significantly up-regulated the expression of FAS in duck preadipocytes (P < 0.05). However, 1000 µM treatment of oleic acid exhibited lipotoxic effect on cell viability (P < 0.05). In addition, during the first 24 h of duck adipocyte differentiation FAS was induced; however, after 24 h its expression level declined (P < 0.05). Conclusion We have successfully cloned and characterized Peking duck FAS. FAS was induced during adipocyte differentiation and by oleic acid treatment. These findings suggest that Peking duck FAS plays a similar role to mammalian FAS during adipocyte differentiation.

In the present study, we investigated the application of 13 short tandem repeat (STR) loci (D13S317, D7S820, TH01, D16S539, CSFIPO, VWA, D8S1179, TPOX, FGA, D3S1358, D21S11, D18S51 and D5S818) routinely used in forensic analysis, for delineating population relationships among seven human populations representing the two major geographic groups, namely the southern and northern Chinese. The resulting single topology revealed pronounced geographic and population partitioning, consistent with the differences in geographic location, languages and eating habits. These findings suggest that forensic STR loci might be particularly powerful tools in providing the necessary fine resolution for reconstructing recent human evolutionary history.