During heat treatment processing, microstructures of heat affected zone （HAZ） were formed in X80 pipe- line steel. After observation by optical microscopy, scanning electron microscopy and transmission electron micr...During heat treatment processing, microstructures of heat affected zone （HAZ） were formed in X80 pipe- line steel. After observation by optical microscopy, scanning electron microscopy and transmission electron microsco- py, microstructure of the as-received X80 steel was confirmed to be acicular ferrite, while the microstructures of quenched, normalized and annealed X80 steels were lath bainite, granular ferrite and quasi-polygonal ferrite, respec- tively. After immersion in the simulated acidic soil solution for 48 h, corrosion rates of these four steels were deter- mined by mass loss measurements and corrosion products were examined by Raman spectroscopy and X-ray photoe lectron spectroscopy. Scanning vibrating electrode technique was used to characterize the micro-galvanic corrosion be- haviors of the synthetic bimetallic electrodes which were formed by coupling each of the simulated HAZ microstruc- tures with the as-received steel in direct physical and electric contact. It is demonstrated that the as-received steel acts as cathode in the as-received/quenched and as-received/normalized couples, while the annealed steel acts as cathode when coupling with the as received steel. The distinction of current density between the galvanic couples reduces with prolonging the immersion time.展开更多
Mechanically stretchable photonics provides a new geometric degree of freedom for photonic system design and foresees applications ranging from artificial skins to soft wearable electronics.Here we describe the design...Mechanically stretchable photonics provides a new geometric degree of freedom for photonic system design and foresees applications ranging from artificial skins to soft wearable electronics.Here we describe the design and experimental realization of the first single-mode stretchable photonic devices.These devices,made of chalcogenide glass and epoxy polymer materials,are monolithically integrated on elastomer substrates.To impart mechanical stretching capability to devices built using these intrinsically brittle materials,our design strategy involves local substrate stiffening to minimize shape deformation of critical photonic components,and interconnecting optical waveguides assuming a meandering Euler spiral geometry to mitigate radiative optical loss.Devices fabricated following such design can sustain 41%nominal tensile strain and 3000 stretching cycles without measurable degradation in optical performance.In addition,we present a rigorous analytical model to quantitatively predict stressoptical coupling behavior in waveguide devices of arbitrary geometry without using a single fitting parameter.展开更多
基金Sponsored by National Natural Science Foundation of China(51171025,51131001)Beijing Postdoctoral Research Foundation of China(2013M540829)
文摘During heat treatment processing, microstructures of heat affected zone （HAZ） were formed in X80 pipe- line steel. After observation by optical microscopy, scanning electron microscopy and transmission electron microsco- py, microstructure of the as-received X80 steel was confirmed to be acicular ferrite, while the microstructures of quenched, normalized and annealed X80 steels were lath bainite, granular ferrite and quasi-polygonal ferrite, respec- tively. After immersion in the simulated acidic soil solution for 48 h, corrosion rates of these four steels were deter- mined by mass loss measurements and corrosion products were examined by Raman spectroscopy and X-ray photoe lectron spectroscopy. Scanning vibrating electrode technique was used to characterize the micro-galvanic corrosion be- haviors of the synthetic bimetallic electrodes which were formed by coupling each of the simulated HAZ microstruc- tures with the as-received steel in direct physical and electric contact. It is demonstrated that the as-received steel acts as cathode in the as-received/quenched and as-received/normalized couples, while the annealed steel acts as cathode when coupling with the as received steel. The distinction of current density between the galvanic couples reduces with prolonging the immersion time.
基金support is provided by the National Science Foundation under award numbers 1453218,1506605,and 1351875facility support by the MIT Microsystems Technology Laboratories and the Harvard University Center for Nanoscale Systemssupported by the National Science Foundation under award 0335765.
文摘Mechanically stretchable photonics provides a new geometric degree of freedom for photonic system design and foresees applications ranging from artificial skins to soft wearable electronics.Here we describe the design and experimental realization of the first single-mode stretchable photonic devices.These devices,made of chalcogenide glass and epoxy polymer materials,are monolithically integrated on elastomer substrates.To impart mechanical stretching capability to devices built using these intrinsically brittle materials,our design strategy involves local substrate stiffening to minimize shape deformation of critical photonic components,and interconnecting optical waveguides assuming a meandering Euler spiral geometry to mitigate radiative optical loss.Devices fabricated following such design can sustain 41%nominal tensile strain and 3000 stretching cycles without measurable degradation in optical performance.In addition,we present a rigorous analytical model to quantitatively predict stressoptical coupling behavior in waveguide devices of arbitrary geometry without using a single fitting parameter.
