The CASTRIP* process produces a range of high strength Ultra-thin Cast Strip (UCS) products (380-550 MPa) in thicknesses between 0.9 mm and 1.5 mm, which is very challenging to produce via conventional hot and cold ro...The CASTRIP* process produces a range of high strength Ultra-thin Cast Strip (UCS) products (380-550 MPa) in thicknesses between 0.9 mm and 1.5 mm, which is very challenging to produce via conventional hot and cold rolled processing routes. The twin roll CASTRIP process fully exploits the hardenability and strengthening potential of Nb in a low C-Mn-Nb-V microalloyed steel type. Significant microstructural strengthening from solute Nb was obtained, even at low microalloying levels, as well as modest Mn additions, through enhancing the hardenability and further strengthening was obtained in coated products by exploiting age hardening during processing on a continuous hot dip galvanising line. Atom probe tomography and TEM determined that Nb was retained in solid solution and subsequent age hardening resulted from the formation of Nb and V rich nanosized particles. Age hardening was achieved without loss of ductility producing galvanised strip with an excellent strength-ductility combination (Y.S. 】600 MPa, T.E. 】10%).展开更多
In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's modulus.However,for dis...In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's modulus.However,for dispersive tssues,the displacement pulse is highly damped and distorted during propagation,diminishing the ffectiveness of peak tracking approaches,and leading to biased cstimates of wave speed.Further,plane wave propagation is sometimes assumed,which contributes to estimation erors.Therefore,we invert a wave propagation model that incorpo-rates propagation,decay,and distortion of pulses in a dispersive media in order to accurately estimate its elastic and viscous components.The model uses a general first-order approximation of dispersion,avoiding the use of any particular rheological model of tisue.Experiments are conducted in elastic and viscoelastic tissue mimicking phantoms by producing a Gaussian push using acoustic radiation force excitation and measuring the wave propagation using a Fourier domain optical coherence tomography system.Results confirmed the ffectiveness of the inversion method in est imat ing viscoelastic parameters in both the viscoelastic and elastic phantoms when compared to mechanical measurements.Finally,the viscoelastic characterization of a fresh porcine comea was conducted.Preliminary results validate this approach when compared to other methods.展开更多
文摘The CASTRIP* process produces a range of high strength Ultra-thin Cast Strip (UCS) products (380-550 MPa) in thicknesses between 0.9 mm and 1.5 mm, which is very challenging to produce via conventional hot and cold rolled processing routes. The twin roll CASTRIP process fully exploits the hardenability and strengthening potential of Nb in a low C-Mn-Nb-V microalloyed steel type. Significant microstructural strengthening from solute Nb was obtained, even at low microalloying levels, as well as modest Mn additions, through enhancing the hardenability and further strengthening was obtained in coated products by exploiting age hardening during processing on a continuous hot dip galvanising line. Atom probe tomography and TEM determined that Nb was retained in solid solution and subsequent age hardening resulted from the formation of Nb and V rich nanosized particles. Age hardening was achieved without loss of ductility producing galvanised strip with an excellent strength-ductility combination (Y.S. 】600 MPa, T.E. 】10%).
文摘In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's modulus.However,for dispersive tssues,the displacement pulse is highly damped and distorted during propagation,diminishing the ffectiveness of peak tracking approaches,and leading to biased cstimates of wave speed.Further,plane wave propagation is sometimes assumed,which contributes to estimation erors.Therefore,we invert a wave propagation model that incorpo-rates propagation,decay,and distortion of pulses in a dispersive media in order to accurately estimate its elastic and viscous components.The model uses a general first-order approximation of dispersion,avoiding the use of any particular rheological model of tisue.Experiments are conducted in elastic and viscoelastic tissue mimicking phantoms by producing a Gaussian push using acoustic radiation force excitation and measuring the wave propagation using a Fourier domain optical coherence tomography system.Results confirmed the ffectiveness of the inversion method in est imat ing viscoelastic parameters in both the viscoelastic and elastic phantoms when compared to mechanical measurements.Finally,the viscoelastic characterization of a fresh porcine comea was conducted.Preliminary results validate this approach when compared to other methods.
