To investigate the effectiveness of self-made zinc alloy sacrificial anode material for the protection of reinforcement in concrete under chlorine salt erosion environment,salt solution immersion corrosion and electro...To investigate the effectiveness of self-made zinc alloy sacrificial anode material for the protection of reinforcement in concrete under chlorine salt erosion environment,salt solution immersion corrosion and electromigration accelerated corrosion tests were used to evaluate the effectiveness of self-made zinc alloy anode with the help of relevant cathodic protection guidelines and evaluation criteria for the corrosion of reinforcement in concrete.The results showed that the protection was effective because the potential of the zinc alloy anode protection steel bar in the salt solution satis?ed the“-780 mV(SCE)”validity criterion.The self-corrosion potential(E_(corr))of the sacri?cial anode protection steel in concrete was greater than-276 mV,and the protective current density of the zinc alloy anode was 1-3μA·cm^(-2),which met the standards of EN12696-2000,further indicating that the self-made zinc alloy sacri?cial anode had a good protection combining with the polarization resistance and the appearance of the corroded surface of the steel in concrete.The microscopic morphology of the corroded surface and the composition of the corrosion products indicates that the mortar of the self-made zinc alloy anode has a lower pH than the imported anodes,so the long-term protection of the selfmade zinc alloy sacri?cial anode needs to be further improved.展开更多
To quantitatively estimate the workability of cement-based grouting material,from the perspective of rheology,the result of the static yield stress evaluated using the rate-controlled and stress-controlled modes,respe...To quantitatively estimate the workability of cement-based grouting material,from the perspective of rheology,the result of the static yield stress evaluated using the rate-controlled and stress-controlled modes,respectively,was compared using the Rheowin rheometer.Also,the correlation of workability and solid concentration of slurry with static yield stress was studied.Results show that the static yield stress of cement-based grouting slurry relates to the established slurry structure,and is the shear stress corresponding to the transformation of elastics to plastics;In rate-controlled mode,the static yield stress of the slurry is related to the shear rate.The higher the shear rate,the greater the yield stress of the slurry.For the stress-controlled mode,the result is more accurate and suitable for testing static yield stress under different water-cement ratios.Since the water-cement ratio has a good correspondence with the static yield stress and the static yield stress has a good correspondence with the slump flow of the slurry,the static yield stress is the minimum stress to be overcome when the slurry begins to flow and it reflects the yield behavior and structural stability of the cement.展开更多
Mountain Yunmeng(37°20′N,113°54′E)is 1520m above sea level and part of the Taihang Mountains.With a temperate continental monsoon climate,the mountain area belongs to the warm temperate deciduous broad-lea...Mountain Yunmeng(37°20′N,113°54′E)is 1520m above sea level and part of the Taihang Mountains.With a temperate continental monsoon climate,the mountain area belongs to the warm temperate deciduous broad-leaved forest region.This thesis was mostly based on the study of more than 2000 packages of bryophytes which were mainly collected by the authors in Mt.Yunmeng,Hebei Province.Of these specimens,there are 36 families,99 genera,and 244 species(including 17 varieties,5 formes,and 1 subspecies)which have been studied and identified.Moreover,it could be seen that Mt.Yunmeng has a diverse population of bryophytes.The bryoflora could be divided into 10 geographical elements:north temperate element make up the majority,accounting for 52.11%of the entire known bryoflora,and another belongs to the East Asian element,accounting for 19.25%.All temperate elements,not including 14 endemic to China and 31 Cosmopolitans,were added up to 188 species,which took 88.3%of all the entire known bryoflora in Mt.Yunmeng.However,there were only 11 Subtropical and Tropical elements.To all appearances,the bryoflora of Mt.Yunmeng showed obvious temperate characteristics.The authors conclude that the bryoflora in Mt.Yunmeng belongs to the middle type,between the warm and dry northern mountain area and the warm and damp southern mountain area.The microclimatic environment greatly influences the bryoflora.展开更多
为制备高性能硅(Si)基锗(Ge)外延材料,采用基于减压化学气相淀积系统(reduced pressure chemical vapor deposition,RPCVD)工艺的低温/高温(low temperature/high temperature,LT/HT)生长技术制备了厚度为1μm的Ge外延材料样品1、2,其中...为制备高性能硅(Si)基锗(Ge)外延材料,采用基于减压化学气相淀积系统(reduced pressure chemical vapor deposition,RPCVD)工艺的低温/高温(low temperature/high temperature,LT/HT)生长技术制备了厚度为1μm的Ge外延材料样品1、2,其中,LT阶段的生长温度为400~450℃,HT阶段的生长温度为700℃。通过原子力显微镜(atomic force microscope,AFM)测试得到样品1、2的材料表面粗糙度均方根(root mean square,RMS)分别为0.66、0.86 nm,样品表面光滑程度较好。同时,根据X射线衍射(X-ray diffraction,XRD)的测试结果得到样品1、2的应变度分别为0.21%、0.23%,Ge的衍射峰对称较好,表明材料结晶质量较高。通过对样品Ⅰ~Ⅳ进行热稳定性试验发现,在700℃条件下对Ge外延材料进行循环热退火,材料可以获得最好的晶体质量。展开更多
基金Funded by Gansu Provincial Department of Transport Scientific Research Project(Nos.2017-16,2017-19)Science and Technology Program of Gansu Provincial Department of Housing and Construction(No.JK2021-11)+2 种基金Science and Technology Project of Gansu Provincial Department of Transportation(No.202102)Natural Science Foundation of Gansu Province(No.20JR10RA170)Gansu Provincial Department of Transportation 2021 the First Batch of the Unveiling of the Hanging System Projects。
文摘To investigate the effectiveness of self-made zinc alloy sacrificial anode material for the protection of reinforcement in concrete under chlorine salt erosion environment,salt solution immersion corrosion and electromigration accelerated corrosion tests were used to evaluate the effectiveness of self-made zinc alloy anode with the help of relevant cathodic protection guidelines and evaluation criteria for the corrosion of reinforcement in concrete.The results showed that the protection was effective because the potential of the zinc alloy anode protection steel bar in the salt solution satis?ed the“-780 mV(SCE)”validity criterion.The self-corrosion potential(E_(corr))of the sacri?cial anode protection steel in concrete was greater than-276 mV,and the protective current density of the zinc alloy anode was 1-3μA·cm^(-2),which met the standards of EN12696-2000,further indicating that the self-made zinc alloy sacri?cial anode had a good protection combining with the polarization resistance and the appearance of the corroded surface of the steel in concrete.The microscopic morphology of the corroded surface and the composition of the corrosion products indicates that the mortar of the self-made zinc alloy anode has a lower pH than the imported anodes,so the long-term protection of the selfmade zinc alloy sacri?cial anode needs to be further improved.
基金Funded by Science and Technology Program of Gansu Provincial Department of Housing and Construction (No.JK2021-11)National Natural Science Fundation of China (No.52161007)+1 种基金Science and Technology Project of Gansu Provincial Department of TransportationNatural Science Foundation of Gansu Province (No. 20JR10RA170)。
文摘To quantitatively estimate the workability of cement-based grouting material,from the perspective of rheology,the result of the static yield stress evaluated using the rate-controlled and stress-controlled modes,respectively,was compared using the Rheowin rheometer.Also,the correlation of workability and solid concentration of slurry with static yield stress was studied.Results show that the static yield stress of cement-based grouting slurry relates to the established slurry structure,and is the shear stress corresponding to the transformation of elastics to plastics;In rate-controlled mode,the static yield stress of the slurry is related to the shear rate.The higher the shear rate,the greater the yield stress of the slurry.For the stress-controlled mode,the result is more accurate and suitable for testing static yield stress under different water-cement ratios.Since the water-cement ratio has a good correspondence with the static yield stress and the static yield stress has a good correspondence with the slump flow of the slurry,the static yield stress is the minimum stress to be overcome when the slurry begins to flow and it reflects the yield behavior and structural stability of the cement.
基金supported by the Natural Science Foundation of Hebei Province (No.301107)the Scientific and Technological Department Brainstorm Plan Project of Hebei Province (No.20034201).
文摘Mountain Yunmeng(37°20′N,113°54′E)is 1520m above sea level and part of the Taihang Mountains.With a temperate continental monsoon climate,the mountain area belongs to the warm temperate deciduous broad-leaved forest region.This thesis was mostly based on the study of more than 2000 packages of bryophytes which were mainly collected by the authors in Mt.Yunmeng,Hebei Province.Of these specimens,there are 36 families,99 genera,and 244 species(including 17 varieties,5 formes,and 1 subspecies)which have been studied and identified.Moreover,it could be seen that Mt.Yunmeng has a diverse population of bryophytes.The bryoflora could be divided into 10 geographical elements:north temperate element make up the majority,accounting for 52.11%of the entire known bryoflora,and another belongs to the East Asian element,accounting for 19.25%.All temperate elements,not including 14 endemic to China and 31 Cosmopolitans,were added up to 188 species,which took 88.3%of all the entire known bryoflora in Mt.Yunmeng.However,there were only 11 Subtropical and Tropical elements.To all appearances,the bryoflora of Mt.Yunmeng showed obvious temperate characteristics.The authors conclude that the bryoflora in Mt.Yunmeng belongs to the middle type,between the warm and dry northern mountain area and the warm and damp southern mountain area.The microclimatic environment greatly influences the bryoflora.
文摘为制备高性能硅(Si)基锗(Ge)外延材料,采用基于减压化学气相淀积系统(reduced pressure chemical vapor deposition,RPCVD)工艺的低温/高温(low temperature/high temperature,LT/HT)生长技术制备了厚度为1μm的Ge外延材料样品1、2,其中,LT阶段的生长温度为400~450℃,HT阶段的生长温度为700℃。通过原子力显微镜(atomic force microscope,AFM)测试得到样品1、2的材料表面粗糙度均方根(root mean square,RMS)分别为0.66、0.86 nm,样品表面光滑程度较好。同时,根据X射线衍射(X-ray diffraction,XRD)的测试结果得到样品1、2的应变度分别为0.21%、0.23%,Ge的衍射峰对称较好,表明材料结晶质量较高。通过对样品Ⅰ~Ⅳ进行热稳定性试验发现,在700℃条件下对Ge外延材料进行循环热退火,材料可以获得最好的晶体质量。
