In the context of research into deep nuclear waste disposal,various works have concerned the hydromechanical behavior of Boom clay,a stiff plastic clay extracted in the SCK-CEN Underground Research Laboratory near the...In the context of research into deep nuclear waste disposal,various works have concerned the hydromechanical behavior of Boom clay,a stiff plastic clay extracted in the SCK-CEN Underground Research Laboratory near the Mol City(Belgium),at a depth of 223 m.Due to some amount of smectite minerals in the clay fraction,Boom clay exhibits swelling properties when hydrated under low stresses.To investigate some aspects of the hydromechanical behavior of Boom clay,oedometer compression tests were carried out on samples of Boom clay close to saturation and submitted to an initial suction.During oedometer compression,the changes in suction with increased vertical stress are monitored by means of a high capacity tensiometer installed at the bottom of the sample.Some aspects related to hydromechanical couplings are examined through the investigation of the changes in suction during oedometer compression,a somewhat delicate and poorly documented experimental approach.A comparison is also made with a completely different soil sample under suction,i.e.a statically compacted unsaturated low plasticity silt.Some technical difficulties typical of this new experimental approach are first described in detail so as to optimize the interpretation of the data obtained.The experiment allows the determination of the point at which suction is changed to positive pressure during compression.Below this point,the ratio between the vertical stress and the change in suction are determined.Above this point,the data show that positive pore pressures are dissipated in a common way.The suction/stress behavior during unloading is also described and discussed.Finally,an interpretation in terms of microstructure effects is provided for both samples.The experimental approach initiated here seems to provide interesting further application to better understand hydromechanical couplings in natural soils in relation with suction increase during stress release.展开更多
Over the past 2 years,many DNA motors have been synthesized and run in living cells,but there are still challenges in designing integrated DNA motors self-powered to enable autonomous intracellular walking without aux...Over the past 2 years,many DNA motors have been synthesized and run in living cells,but there are still challenges in designing integrated DNA motors self-powered to enable autonomous intracellular walking without auxiliary additives.Herein,we report a smart strategy based on a DNA motor–MnO2 nanocomposite,which successfully meets these requirements of intracellular analysis and enables sensitive imaging of specific microRNAs(miRNAs)in living cells.展开更多
基金EURIDICE (European Undenground Research Infn-structure for Disposal of nuclear waste In Clay Environment, Mol, Belgium)is gatefully acknowledged for the financial support provided for this workthat is part of the fist author's PhD thesis.
文摘In the context of research into deep nuclear waste disposal,various works have concerned the hydromechanical behavior of Boom clay,a stiff plastic clay extracted in the SCK-CEN Underground Research Laboratory near the Mol City(Belgium),at a depth of 223 m.Due to some amount of smectite minerals in the clay fraction,Boom clay exhibits swelling properties when hydrated under low stresses.To investigate some aspects of the hydromechanical behavior of Boom clay,oedometer compression tests were carried out on samples of Boom clay close to saturation and submitted to an initial suction.During oedometer compression,the changes in suction with increased vertical stress are monitored by means of a high capacity tensiometer installed at the bottom of the sample.Some aspects related to hydromechanical couplings are examined through the investigation of the changes in suction during oedometer compression,a somewhat delicate and poorly documented experimental approach.A comparison is also made with a completely different soil sample under suction,i.e.a statically compacted unsaturated low plasticity silt.Some technical difficulties typical of this new experimental approach are first described in detail so as to optimize the interpretation of the data obtained.The experiment allows the determination of the point at which suction is changed to positive pressure during compression.Below this point,the ratio between the vertical stress and the change in suction are determined.Above this point,the data show that positive pore pressures are dissipated in a common way.The suction/stress behavior during unloading is also described and discussed.Finally,an interpretation in terms of microstructure effects is provided for both samples.The experimental approach initiated here seems to provide interesting further application to better understand hydromechanical couplings in natural soils in relation with suction increase during stress release.
基金support from the National Key R&D Program of China(grant no.2016YFA0201200)the National Natural Science Foundation of China(grant no.21991080)the Excellent Research Program of Nanjing University(ZYJH004).
文摘Over the past 2 years,many DNA motors have been synthesized and run in living cells,but there are still challenges in designing integrated DNA motors self-powered to enable autonomous intracellular walking without auxiliary additives.Herein,we report a smart strategy based on a DNA motor–MnO2 nanocomposite,which successfully meets these requirements of intracellular analysis and enables sensitive imaging of specific microRNAs(miRNAs)in living cells.