The concrete arch bridge is a natural and appropriate structural solution,aesthetically pleasing and easily integrated into the environment,especially in mountainous and island areas.However,construction difficulty an...The concrete arch bridge is a natural and appropriate structural solution,aesthetically pleasing and easily integrated into the environment,especially in mountainous and island areas.However,construction difficulty and cost will increase with heavy self-weight when the span enlarges.A potential solution is to use a composite box arch ring with steel web-concrete flange.Taking Wanzhou Yangtze River Bridge(the longest concrete arch bridge in the world with a main span of 420 m)as a prototype,trial designs of a composite box arch with steel webs(including corrugated steel webs and plain steel webs)and concrete flanges were carried out.Comparison of quantities and structural behaviors of the prototype concrete arch with the two trial designed composite arch was presented.It is shown that the selfweight of the composite arch can reduce about 28%and the structures can meet the design requirements,therefore it is possible to use the two composite arches in long span arch bridges.展开更多
N-Acety-L-cysteine(NAC),enriched with multiple electron-rich groups involving-SH,-C=O,and-COOH,exhibits strong affinities to transition metal ions.Herein,NAC was adopted as the stabilizing agent to synthesize a series...N-Acety-L-cysteine(NAC),enriched with multiple electron-rich groups involving-SH,-C=O,and-COOH,exhibits strong affinities to transition metal ions.Herein,NAC was adopted as the stabilizing agent to synthesize a series of peroxidase-like Pt nanoclusters(NCs)with different physicochemical properties.Both the cluster size and the charge state of NAC-Pt NCs are highly dependent upon the molar ratio of[K_(2)PtCl_(4)]/[NAC],contributing to different peroxidase mimicking activities.The most active Pt nanozyme(~1.7 nm),composed of 60%metallic Pt^(0) and 40%positively charged Pt^(2+)respectively,exhibits the K_(m) of 0.132 mM for 3,3′,5,5′-tetramethylbenzidine and 35 mM for H_(2)O_(2).Based on the heparin-activated enzymatic activ-ity of NAC-Pt at pH 6.0,an ultrasensitive test was established for quantitative determination of heparin,giving the linear response of 0.5-20μg/mL as well as the limit of detection of 2×10^(−3)μg/mL.This proposed method is also applicable in biological fluid for practical applications.Such a colorimetric method possesses several advantages involving high sensitiv-ity,short response,eco-friendly synthesis,low consumption of material and energy,free of expensive instrument,as well as simple operation.展开更多
基金This work was supported by the International Science and Technology Cooperation Projects(No.2009DFA72220)Shanghai Post-Doctoral Projects(No.10R21416100).
文摘The concrete arch bridge is a natural and appropriate structural solution,aesthetically pleasing and easily integrated into the environment,especially in mountainous and island areas.However,construction difficulty and cost will increase with heavy self-weight when the span enlarges.A potential solution is to use a composite box arch ring with steel web-concrete flange.Taking Wanzhou Yangtze River Bridge(the longest concrete arch bridge in the world with a main span of 420 m)as a prototype,trial designs of a composite box arch with steel webs(including corrugated steel webs and plain steel webs)and concrete flanges were carried out.Comparison of quantities and structural behaviors of the prototype concrete arch with the two trial designed composite arch was presented.It is shown that the selfweight of the composite arch can reduce about 28%and the structures can meet the design requirements,therefore it is possible to use the two composite arches in long span arch bridges.
基金This study was funded by National Natural Science Foundation of China(21878225,21776215).
文摘N-Acety-L-cysteine(NAC),enriched with multiple electron-rich groups involving-SH,-C=O,and-COOH,exhibits strong affinities to transition metal ions.Herein,NAC was adopted as the stabilizing agent to synthesize a series of peroxidase-like Pt nanoclusters(NCs)with different physicochemical properties.Both the cluster size and the charge state of NAC-Pt NCs are highly dependent upon the molar ratio of[K_(2)PtCl_(4)]/[NAC],contributing to different peroxidase mimicking activities.The most active Pt nanozyme(~1.7 nm),composed of 60%metallic Pt^(0) and 40%positively charged Pt^(2+)respectively,exhibits the K_(m) of 0.132 mM for 3,3′,5,5′-tetramethylbenzidine and 35 mM for H_(2)O_(2).Based on the heparin-activated enzymatic activ-ity of NAC-Pt at pH 6.0,an ultrasensitive test was established for quantitative determination of heparin,giving the linear response of 0.5-20μg/mL as well as the limit of detection of 2×10^(−3)μg/mL.This proposed method is also applicable in biological fluid for practical applications.Such a colorimetric method possesses several advantages involving high sensitiv-ity,short response,eco-friendly synthesis,low consumption of material and energy,free of expensive instrument,as well as simple operation.
