In this article, a topological sensitivity framework for far-field detection of a diamet- rically small electromagnetic inclusion is established. The cases of single and multiple measurements of the electric far-field...In this article, a topological sensitivity framework for far-field detection of a diamet- rically small electromagnetic inclusion is established. The cases of single and multiple measurements of the electric far-field scattering amplitude at a fixed frequency are tak- en into account. The performance of the algorithm is analyzed theoretically in terms of its resolution and sensitivity for locating an inclusion. The stability of the framework with respect to measurement and medium noises is discussed. Moreover, the quantitative results for signal-to-noise ratio are presented. A few numerical results are presented to illustrate the detection capabilities of the proposed framework with single and multiple measurements.展开更多
Rapid transient explosive boiling of mixed ethanol and acetone of different volume fractions were investigated experimentally. The temperature of the metal film surface irradiated by a pulse laser was measured by a fa...Rapid transient explosive boiling of mixed ethanol and acetone of different volume fractions were investigated experimentally. The temperature of the metal film surface irradiated by a pulse laser was measured by a fast-response measurement system with a platinum film resistor. The behaviors of bubbles, including their formation, growth, departure and floating-up, were observed and captured by a microscope camera system. It was found that bubble nucleation temperature depends strongly on the heating rate. Some special characteristics different from those of conventional boiling were revealed, and the factors affecting explosive boiling were studied.展开更多
A white light spectral interferometry based on a Linnik type system was established to accurately measure the thin film thickness through transparent medium.In practical work,the equivalent thickness of a beam splitte...A white light spectral interferometry based on a Linnik type system was established to accurately measure the thin film thickness through transparent medium.In practical work,the equivalent thickness of a beam splitter and the mismatch of the objective lens introduce nonlinear phase errors.Adding a transparent medium also increases the equivalent thickness.The simulation results showthat the equivalent thickness has a significant effect on thin film thickness measurements.Therefore,it is necessary to perform wavelength correction to provide a constant equivalent thickness for beamsplitters.In the experiments,some pieces of cover glasses as the transparent medium were added to the measured beam and then a standard thin film thickness of 1052.2±0.9 nm was tested through the transparent medium.The results demonstrate that our system has a nanometer-level accuracy for thin film thickness measurement through transparent medium with optical path compensation.展开更多
文摘In this article, a topological sensitivity framework for far-field detection of a diamet- rically small electromagnetic inclusion is established. The cases of single and multiple measurements of the electric far-field scattering amplitude at a fixed frequency are tak- en into account. The performance of the algorithm is analyzed theoretically in terms of its resolution and sensitivity for locating an inclusion. The stability of the framework with respect to measurement and medium noises is discussed. Moreover, the quantitative results for signal-to-noise ratio are presented. A few numerical results are presented to illustrate the detection capabilities of the proposed framework with single and multiple measurements.
基金This work was supported by the State Key Fundamental Research Plan of China(No.G2000026305)the National Natural Science Foundation of China(Grant No.50276060)the Institute of Engineering Thermophysics,the Chinese Academy of Sciences.
文摘Rapid transient explosive boiling of mixed ethanol and acetone of different volume fractions were investigated experimentally. The temperature of the metal film surface irradiated by a pulse laser was measured by a fast-response measurement system with a platinum film resistor. The behaviors of bubbles, including their formation, growth, departure and floating-up, were observed and captured by a microscope camera system. It was found that bubble nucleation temperature depends strongly on the heating rate. Some special characteristics different from those of conventional boiling were revealed, and the factors affecting explosive boiling were studied.
基金the support of The National Key Research and Development Program of China(Grant No.2017YFF0107001)the 111 Project fund(Grant No.B07014)
文摘A white light spectral interferometry based on a Linnik type system was established to accurately measure the thin film thickness through transparent medium.In practical work,the equivalent thickness of a beam splitter and the mismatch of the objective lens introduce nonlinear phase errors.Adding a transparent medium also increases the equivalent thickness.The simulation results showthat the equivalent thickness has a significant effect on thin film thickness measurements.Therefore,it is necessary to perform wavelength correction to provide a constant equivalent thickness for beamsplitters.In the experiments,some pieces of cover glasses as the transparent medium were added to the measured beam and then a standard thin film thickness of 1052.2±0.9 nm was tested through the transparent medium.The results demonstrate that our system has a nanometer-level accuracy for thin film thickness measurement through transparent medium with optical path compensation.
