ABSTRACT
The mechanical performance of curved bridges under the action of an earthquake is complex. To obtain the influence of seismic parameters on the seismic response of curved girder bridges, this paper relies on a large slope small-radius curved steel box girder bridge (LSCGB) and selects seismic wave incidence angle, vertical component of ground motion, and site category as seismic parameters to carry out nonlinear time history analysis. Based on the analysis results of the case bridge, it is shown that the torsional vibration of the first 10 modes of LSCGB is significant, the modes are dispersed, and the contribution of high-order modes of vibration cannot be ignored. The most unfavorable seismic wave incidence angle is in the direction of 45°â¼60° counterclockwise Angle from the central connection line of Pier No. 1 and Pier No. 4 of the bridge. The seismic response of the curved bridge components increases with the vertical seismic intensity, and the influence on displacement responses is more significant. The basic vibration period of curved girder bridges built on soft soil sites is extended by approximately 18.23%, and the seismic response of key components increases with the softening of the site soil. Therefore, when analyzing the seismic response of LSCGBs, the influence of vertical component of ground motion and site category should not be ignored.
Subject(s)
Earthquakes , Vibration , Motion , Models, Theoretical , SteelABSTRACT
A facile and efficient radical tandem vinylogous aldol and intramolecular [2 + 2] cycloaddition reaction for direct synthesis of cyclobutane-containing benzocyclobutenes (BCBs) under extremely mild conditions without using any photocatalysts is reported. This approach exhibited definite compatibility with functional groups and afforded new BCBs with excellent regioselectivity and high yields. Moreover, detailed mechanism studies were carried out both experimentally and theoretically. The readily accessible, low-cost, and ecofriendly nature of the developed strategy will endow it with attractive applications in organic and medicinal chemistry.
ABSTRACT
OBJECTIVE: To verify the effects of treatment with blood transfusion and scopolamine on severe chlorphenamidine poisoning (SCP). METHODS: 400 patients with severe oral chlorphenamidine poisoning were randomly divided into two groups. 200 patients (Group I) were treated with the traditional combined therapy including gastrolavage, purgation and taking redox agent (methylene blue and vitamin C) while the other 200 patients (Group II) in addition to the above mentioned therapy, received blood transfusion and scopolamine injection. RESULTS: The cure rate of Group II was 99.5% and significantly higher than that of Group I (91.0%, P < 0.01). The average time of improving in health in Group II [(8.71 +/- 1.49) h] was obviously shorter than those in Group I [(10.65 +/- 1.72) h, P < 0.01]. Blood methemoglobin concentrations in Group II at 3, 7, 12, 24 h after admission [(43.58 +/- 2.69), (34.21 +/- 2.30), (20.60 +/- 4.03), (13.50 +/- 1.65) g/L respectively] were obviously lower than those in Group I [(54.42 +/- 12.79), (42.17 +/- 22.34), (30.66 +/- 17.67), (19.01 +/- 0.61) g/L respectively, P < 0.01]. CONCLUSION: Blood transfusion and scopolamine had distinctive therapeutic effect on SCP to makeup the deficiency of redox agent. Combination of three therapies may potentiate the detoxication for chlorphenamidine.