The sealing integrity of cement sheath in offshore wells is seriously threatened under high-temperature conditions,resulting in gas channeling and other problems.Given the lack of experimental results,in this study re...The sealing integrity of cement sheath in offshore wells is seriously threatened under high-temperature conditions,resulting in gas channeling and other problems.Given the lack of experimental results,in this study relevant samples of a cement slurry sealing section of a typical offshore high-temperature well have been prepared and analyzed.In particular,the mechanical properties have been assessed with a triaxial pressure servo instrument and a high-temperature curing kettle.The density and the Poisson’s ratio of the samples have also been tested.The stress-strain curve has been drawn to obtain the elastic modulus and the compressive strength.The rock brittleness index has been calculated according to the measured elastic modulus and the Poisson’s ratio,together with the brittleness and the compressibility of the cement samples.The test results show that the mechanical properties and bonding strength of the cement samples are optimal at 130°C,medium at 150°C,and poor at 180°C.展开更多
Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbon...Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbonation methods was tested through XRD and SEM,the mechanical property and microstructure of recycled powder mortar with three replacement rates were studied by ISO method and SEM,and the strengthening mechanism was analyzed.The results showed that the mechanical property of recycled powder mortar decreased with the increasing of replacement rate.It is suggested that the replacement rate of recycled powder should not exceed 20%.The strength index and activity index of carbonated recycled powder mortar were improved,in which the flexural strength was increased by 27.85%and compressive strength was increased by 20%at the maximum.Recycled powder can be quickly and completely carbonated,and the improvement effect of CH pre-soaking carbonation was the best.The activity index of carbonated recycled powder can meet the requirements of Grade II technical standard for recycled powder.Microscopic results revealed the activation mechanism of carbonated recycled powder such as surplus calcium source effect,alkaline polycondensation effect and carbonation enhancement effect.展开更多
Novel transparent ceramics of Zr4+ doped Ba(Mg,Ta)O3(BMT)with a high refractive index of 2.037 at 587.56 nm were successfully fabricated via high temperature solid-state-reaction sintering method.To make it transparen...Novel transparent ceramics of Zr4+ doped Ba(Mg,Ta)O3(BMT)with a high refractive index of 2.037 at 587.56 nm were successfully fabricated via high temperature solid-state-reaction sintering method.To make it transparent,the pure cubic Ba(Zr,Mg,Ta)O3 phases(BZMT)were realized in advance by skillfully modulating the lattice structure of BMT from trigonal symmetric to cubic symmetric through doping Zr4+ into the lattice of BMT crystal.Highly optical transmittance of 74% at 650 n,,which hit the upper limit of the theory,was achieved for BZMT.Both abbe number of 23.4 and the bandgap Eg of 3.22 eV have been calculated.展开更多
A semi-parametric single-index model based approach was proposed for prediction of mechanical properties of hot rolled strip. Based on industrial production data, a semi-parametric single-index model was developed by ...A semi-parametric single-index model based approach was proposed for prediction of mechanical properties of hot rolled strip. Based on industrial production data, a semi-parametric single-index model was developed by choo-sing the appropriate kernel function and window width to predict the yield strength, tensile strength and elongation. When data samples are limited, compared with regression method and neural network method, the prediction results show that the semi-parametric single-index model based method is more adaptive and the prediction performance is superior to those by both regression and neural network methods.展开更多
基金The authors gratefully acknowledge the research project from Engineering Research Center of Rock-Soil Drilling&Excavation and Protection,Ministry of EducationChina University of Geosciences,Wuhan(Grant No.202106).
文摘The sealing integrity of cement sheath in offshore wells is seriously threatened under high-temperature conditions,resulting in gas channeling and other problems.Given the lack of experimental results,in this study relevant samples of a cement slurry sealing section of a typical offshore high-temperature well have been prepared and analyzed.In particular,the mechanical properties have been assessed with a triaxial pressure servo instrument and a high-temperature curing kettle.The density and the Poisson’s ratio of the samples have also been tested.The stress-strain curve has been drawn to obtain the elastic modulus and the compressive strength.The rock brittleness index has been calculated according to the measured elastic modulus and the Poisson’s ratio,together with the brittleness and the compressibility of the cement samples.The test results show that the mechanical properties and bonding strength of the cement samples are optimal at 130°C,medium at 150°C,and poor at 180°C.
基金Funded by Joint Funds of the National Natural Science Foundation of China(No.U1904188)Jiangxi Provincial Department of Education Science and Technology Project(Nos.GJJ171079,GJJ181023 and GJJ181022)。
文摘Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbonation methods was tested through XRD and SEM,the mechanical property and microstructure of recycled powder mortar with three replacement rates were studied by ISO method and SEM,and the strengthening mechanism was analyzed.The results showed that the mechanical property of recycled powder mortar decreased with the increasing of replacement rate.It is suggested that the replacement rate of recycled powder should not exceed 20%.The strength index and activity index of carbonated recycled powder mortar were improved,in which the flexural strength was increased by 27.85%and compressive strength was increased by 20%at the maximum.Recycled powder can be quickly and completely carbonated,and the improvement effect of CH pre-soaking carbonation was the best.The activity index of carbonated recycled powder can meet the requirements of Grade II technical standard for recycled powder.Microscopic results revealed the activation mechanism of carbonated recycled powder such as surplus calcium source effect,alkaline polycondensation effect and carbonation enhancement effect.
基金Supported by the National Key Research and Development Program of China(2017YFB0403200)
文摘Novel transparent ceramics of Zr4+ doped Ba(Mg,Ta)O3(BMT)with a high refractive index of 2.037 at 587.56 nm were successfully fabricated via high temperature solid-state-reaction sintering method.To make it transparent,the pure cubic Ba(Zr,Mg,Ta)O3 phases(BZMT)were realized in advance by skillfully modulating the lattice structure of BMT from trigonal symmetric to cubic symmetric through doping Zr4+ into the lattice of BMT crystal.Highly optical transmittance of 74% at 650 n,,which hit the upper limit of the theory,was achieved for BZMT.Both abbe number of 23.4 and the bandgap Eg of 3.22 eV have been calculated.
基金Item Sponsored by National Key Technology Research and Development Program of China (2006BAE03A09)National Natural Science Foundation of China ( 61203219 )
文摘A semi-parametric single-index model based approach was proposed for prediction of mechanical properties of hot rolled strip. Based on industrial production data, a semi-parametric single-index model was developed by choo-sing the appropriate kernel function and window width to predict the yield strength, tensile strength and elongation. When data samples are limited, compared with regression method and neural network method, the prediction results show that the semi-parametric single-index model based method is more adaptive and the prediction performance is superior to those by both regression and neural network methods.
