New-old concrete composite system usually exists in concrete repairing structure.In the present work,series of experiments were carried out to investigate permeability and ion diffusion properties of new-old concrete ...New-old concrete composite system usually exists in concrete repairing structure.In the present work,series of experiments were carried out to investigate permeability and ion diffusion properties of new-old concrete composite by measuring 6-hour coulomb charge and chloride diffusivity.The interrelation among transport properties of new-old composites,new,and old concretes was also discussed.Results indicate that the permeability and chloride diffusivity of new-old concrete composite system closely interrelate to the corresponding new concrete and old concrete.The interfacial transition zone between new concrete and old concrete greatly influences the transport property of new-old concrete system.Compared with the corresponding new concrete and old concrete lower permeability and diffusivity values for the new-old concrete composites can be achieved by choosing suitable new concrete.It is possible to design the tailor-made new-old concrete composite system for repair given the transport property.展开更多
To obtain the influence rules of the coating parameters of a long-period fiber grating(LPFG)with respect to temperature,strain and refractive index sensing properties,based on the mode coupling theory,a strict four-la...To obtain the influence rules of the coating parameters of a long-period fiber grating(LPFG)with respect to temperature,strain and refractive index sensing properties,based on the mode coupling theory,a strict four-layer theorietical model of a metal film coated LPFG is established,and these parameters that affect the spectral characteristics of the metal film coated LPFG are studied.The simulation results show that there is an optimal metal film thickness on the surface of the LPFG that will induce the surface-plasmon resonance(SP R)effect,which results in higher sensitivity to the environmental temperature and refractive index but has little influence on the strain There is theoretical evidence that when the silver thickness is between0.8and1.2nm,the refractive index sensitivity will reach the peak point of42.4026,at which the refractive index sensor sensitivity is increased by4.S%.The theoretical results of coating a long-period fiber grating provide a good theoretical basis and guidance for LPFG design and parameters optimization展开更多
For the development of ultra-sensitive electrical bio/chemical sensors based on nanowire field effect transistors （FETs）, the influence of the ions in the solution on the electron transport has to be understood. For...For the development of ultra-sensitive electrical bio/chemical sensors based on nanowire field effect transistors （FETs）, the influence of the ions in the solution on the electron transport has to be understood. For this purpose we establish a simulation platform for nanowire FETs in the liquid environment by implementing the modified Poisson-Boltzmann model into Landauer transport theory. We investigate the changes of the electric potential and the transport characteristics due to the ions. The reduction of sensitivity of the sensors due to the screening effect from the electrolyte could be successfully reproduced. We also fabricated silicon nanowire Schottky-barrier FETs and our model could capture the observed reduction of the current with increasing ionic concentration. This shows that our simulation platform can be used to interpret ongoing experiments, to design nanowire FETs, and it also gives insight into controversial issues such as whether ions in the buffer solution affect the transport characteristics or not.展开更多
基金Project(2013CB036201)supported by the National Basic Research Program of ChinaProject(51178467)supported by National Natural Science Foundation of ChinaProject(NCET-10-0839)supported by Program for New Century Excellent Talents in University,China
文摘New-old concrete composite system usually exists in concrete repairing structure.In the present work,series of experiments were carried out to investigate permeability and ion diffusion properties of new-old concrete composite by measuring 6-hour coulomb charge and chloride diffusivity.The interrelation among transport properties of new-old composites,new,and old concretes was also discussed.Results indicate that the permeability and chloride diffusivity of new-old concrete composite system closely interrelate to the corresponding new concrete and old concrete.The interfacial transition zone between new concrete and old concrete greatly influences the transport property of new-old concrete system.Compared with the corresponding new concrete and old concrete lower permeability and diffusivity values for the new-old concrete composites can be achieved by choosing suitable new concrete.It is possible to design the tailor-made new-old concrete composite system for repair given the transport property.
基金National Natural Science Foundation of China(No.51309001)Scientific Research Key Project of Anhui Province(No.KJ2017A041)
文摘To obtain the influence rules of the coating parameters of a long-period fiber grating(LPFG)with respect to temperature,strain and refractive index sensing properties,based on the mode coupling theory,a strict four-layer theorietical model of a metal film coated LPFG is established,and these parameters that affect the spectral characteristics of the metal film coated LPFG are studied.The simulation results show that there is an optimal metal film thickness on the surface of the LPFG that will induce the surface-plasmon resonance(SP R)effect,which results in higher sensitivity to the environmental temperature and refractive index but has little influence on the strain There is theoretical evidence that when the silver thickness is between0.8and1.2nm,the refractive index sensitivity will reach the peak point of42.4026,at which the refractive index sensor sensitivity is increased by4.S%.The theoretical results of coating a long-period fiber grating provide a good theoretical basis and guidance for LPFG design and parameters optimization
文摘For the development of ultra-sensitive electrical bio/chemical sensors based on nanowire field effect transistors （FETs）, the influence of the ions in the solution on the electron transport has to be understood. For this purpose we establish a simulation platform for nanowire FETs in the liquid environment by implementing the modified Poisson-Boltzmann model into Landauer transport theory. We investigate the changes of the electric potential and the transport characteristics due to the ions. The reduction of sensitivity of the sensors due to the screening effect from the electrolyte could be successfully reproduced. We also fabricated silicon nanowire Schottky-barrier FETs and our model could capture the observed reduction of the current with increasing ionic concentration. This shows that our simulation platform can be used to interpret ongoing experiments, to design nanowire FETs, and it also gives insight into controversial issues such as whether ions in the buffer solution affect the transport characteristics or not.
